Electrically rechargeable, metal anode cell and battery systems and methods

[0001] The invention relates to an electrically rechargeable battery and a storage battery assembly.

BACKGROUND OF THE INVENTION [0002] The combination of an aging electrical network infrastructure and the integration of discontinuous generation sources from large-scale renewable energy resources (such as wind, sun and ocean waves) has increased the significant need to develop effective energy storage technologies to achieve grid power stability and changes in supply electricity during peak and off-peak periods. Electricity suppliers are looking for ways to add clean energy to the grid, preventing interruptions in energy supply, and managing peak loads cost-effectively without adding additional generation capacity. Batteries are key elements in the development and large-scale use of renewable energy sources, such as wind farms and solar farms.

[0003] To date, no single battery system in this application has been successful on the market. There are many reasons for this. One reason is the high cost of existing battery systems. Consequently, electricity suppliers prefer the use of gas turbines to supply peak power to the grid when needed. However, gas turbines are not as versatile or useful as proper storage devices such as batteries. The second reason is that the life cycle of current batteries is too short, which means that the real operating costs are much higher than the initial cost of the battery. Another reason is that many batteries (such as sodium-sulfur batteries) operate at elevated temperatures, contain hazardous chemicals, or may undergo secondary harmful chemical reactions, such as those found in lithium-based batteries. In short, there is currently no battery technology available on the market that would offer batteries of a suitable size for large scale, adequate performance and long life cycle related to discharging / charging at a cost-effective price and an appropriate lifetime for electricity suppliers.

[0004] Ideally, the electrochemical charging of a cell or battery is such that 60% or more, preferably 80% or more, and more preferably 90% or more of the discharge capacity of the cell or battery may be available again for useful discharge capacity during the electrochemical period charging of one hour or less, and preferably within 30 minutes or less.

[0005] There is therefore a need for improved battery systems. There is also a need for battery configurations that are cost effective.

[0006] DE 18 05 022 A1 relates to electrochemical cells comprising gas diffusion type electrodes that are partially immersed in the electrolyte, the remaining part of the electrode being in contact with the gas medium. In particular, DE 18 05 022 A1 discloses a charge cell comprising a metal electrode and an electrode in contact with air comprising a metal mesh as a current collector and an air-permeable hydrophobic membrane. The overflow bank configured to capture excess electrolyte that overflows from above is not described in the document.

SUMMARY OF THE INVENTION [0007] The present invention is defined by the subject matter of independent claims 1 and 7, and provides a solution to one or more of the technical problems described above.

[0008] The present invention provides a new design for the rechargeable metal anode system and battery chemistry is provided in accordance with various aspects of the present invention. This cell design with a metal anode introduces a significant number of novel and previously unexplored chemical, material, structural and structural changes. Various changes and modifications to this zinc anode battery system will be described in more detail below. In some embodiments, the metal anode cell may be a zinc-air cell. The new battery system was successfully discharged and electrically charged more than 1800 times without any signs of air cathode decay. Based on these results, a long service life is expected. Some (or all) of the changes listed here can be combined for long life cycle cell performance, which can make this zinc-air system both inexpensive and practical.

[0009] An aspect of the invention relates to a rechargeable metal anode cell, which contains a metal electrode; an air contacting electrode comprising at least one current collector having a corrosion resistant outer layer comprising titanium carbide, conductive inner layer containing titanium and an air-permeable hydrophobic membrane; an aqueous electrolyte sandwiched between a metal electrode and an air contacting electrode; and a casing supporting both a metal electrode and an electrode contacting the air in such a way, that the metal electrode and the air contacting electrode are at a constant distance from each other, to create space, in which there is a water electrolyte, which housing comprises an electrolyte management system formed entirely in the housing, which electrolyte management system includes: a drain or filling connection; overflow bank configured to capture and store aqueous electrolyte inside the cell, when the aqueous electrolyte overflows from one of the upper electrolyte tanks or covering the top of the cell arranged vertically in a pile on top of the contacting electrode of the cell, where the metal electrode is in direct contact with the aqueous electrolyte, and without ion-conducting material and electrically insulating material between the contacting air electrode, and water electrolyte, where the excess of aqueous electrolyte inside the cell is poured through the overflow bank to the drain or filling connection, which drain or filling connection allows the excess water electrolyte to drip into one of the electrolyte trapping tanks or to the underlying cell vertically stacked under the metal electrode of the cell. Also described is a rechargeable metal anode cell that may include a metal electrode; an air contacting, porous electrode containing a catalyst; and an aqueous electrolyte between the metal electrode and the air contacting, porous electrode, where the metal electrode is in direct contact with the aqueous electrolyte, and where a separator between the air contacting electrode and the metal electrode is not provided or required. In some additional embodiments, no separator is provided between the air contacting electrode and the electrolyte.

[0010] The metal may include any metal, metal alloy, intermetallic material, mishmetals or mixtures of the above-mentioned materials.

[0011] Metals may also include clad materials, where one metal is coated on another metal or other suitable conductive substrate. This may also include triple clad materials, where one metal (or metal alloy) is coated on the other metal (or a suitable conductive substrate), and in turn, a third metal (or metal alloy) is coated on top of the two metals. The underlying metal and the metal may be coated with the same metal or alloy as with any other metal or alloy. A simple example of metal cladding may include the case where metal A is coated on metal B. Metal A can be the same as metal B or it can be another metal. The triple-plated material can consist of three separate metals, for example metal C coated on top of metal A, which in turn is coated on metal B. Metal C can be either the same as metal A or B, or it can be a completely different metal. Examples may include copper or nickel coated titanium. Another suitable metal may be coated between titanium and copper. Any number of metals and / or other conductive materials may be clad, including, but not limited to, two, three, four, five, six, seven or more. Each of the clad materials and / or substrates may be any conductive material that may include, but is not limited to, metal (e.g. copper, nickel, aluminum, titanium, silver, gold, iron, steel, brass, platinum, palladium), any other electrically conductive material and / or any other material described elsewhere herein.

[0012] Intermetallic may refer to compositions that consist exclusively of metal atoms that are bonded to each other by metallic bonds in non-stoichiometric ratios. Examples may include, but are not limited to, Ag-Ni, Ag-Au, PdPt, Pt0.5Au0.5, PdNi, PdIr or AxBy, where A is ruthenium, palladium, rhenium, iridium or platinum, B is aluminum, scandium, yttrium, lanthanides, titanium, zirconium, hafnium, vanadium, niobium or tantalum, ax and y are suitable subscripts such that x and y are integers and both are greater than or equal to 1 (e.g. 1, 2, 3, 4, 5, 6, 7, 8 or the like) and x + y is greater than or equal to two.

[0013] The separator may comprise generally porous material intended to separate or electrically isolate the cathode from the anode. This material can be ion conductive, but electrically insulating. Due to the placement between the cathode and anode, the separator can reduce the convection flow by ~ 20%. The separator can reduce ion transport (more than what would have happened if the separator was not present) by ~ 15%.

[0014] The air contacting electrode may contain electrically conductive, porous material that is in contact with the air. This porosity may allow oxygen to diffuse from the air through the pores and to come into physical and electrical contact with the material in the electrode. Usually one side of the gas-contacting electrode is in contact with the gas phase (for example, the air space in the metal anode cell) and the other side is exposed to the electrolyte phase. In a bipolar cell configuration, electrical contact is provided between the electrode contacting the air of one cell and the anode of the adjacent cell.

[0015] Another aspect of the invention relates to a storage battery assembly comprising a first cell having a first metal electrode, a first air contacting electrode comprising at least one current collector having a corrosion resistant outer layer comprising titanium carbide, conductive inner layer containing titanium, and an air-permeable hydrophobic membrane, electrolyte between them and the first housing supporting both the first metal electrode and the first electrode in contact with air at a constant distance from each other, to create the first space, which contains electrolyte a first housing including a first overflow edge configured to maintain a constant electrolyte level within the first cell; a second cell having a second metal electrode, a second air contacting electrode comprising at least one current collector having a corrosion resistant outer layer comprising titanium carbide, conductive inner layer containing titanium and an air-permeable hydrophobic membrane, and a second housing supporting both the second metal electrode, as well as a second electrode that contacts the air at a constant distance from each other, to create a second space, which second housing includes a second overflow edge configured to capture excess electrolyte, which overflows through the first overflow bank and storage of the captured electrolyte inside the second space, where the metal electrode of the first cell is in contact with the air electrode of the second cell in such a way, that an air channel is formed between the metal electrode of the first cell and the electrode of the second cell contacting the air, and where both the metal electrode, as well as the air contacting electrode of the first and second links are positioned substantially horizontally.

Also described here is a rechargeable metal anode cell system comprising a metal electrode; an air contacting electrode; and an aqueous electrolyte solution at a pH in the range of from about 3 to about 10 (e.g., from about 3.5 to about 9.5, from about 4 to about 9, or from about 5 to about 8), where the battery cell system is suitable for at least 500 or more discharging and recharging cycles without physical degradation of materials or significant reduction in cell and system performance.

[0016] A set of cells may be provided in accordance with another aspect of the invention. The battery pack may contain a number of separate cells. Each cell can contain a metal electrode, an air contacting electrode containing a catalyst and a liquid electrolyte between them. The first cell can be connected to the second cell also containing a metal electrode, an air contacting electrode, and a liquid electrolyte between them. These two cells are connected in a way that the metal electrode of cell # 1 is in contact with the electrode contacting the air of cell # 2. This allows an air space or channel to be created between the # 1 cell electrode and the # 2 electrode in contact with the air. In this configuration, the metal electrode and the air contacting electrode are parallel to each other and horizontally oriented.

[0017] Also disclosed is an energy storage system comprising: a liquid electrolyte supply assembly having a flow control element that is configured to distribute (e.g., add or remove) the liquid electrolyte, as needed, to individual cells. It may include at least one connection comprising an overflow portion, where the flow control element allows excess or excess electrolyte to overflow from each individual cell in the battery if the electrolyte volumes in that cell increase significantly. It may also enable refilling of individual fire within the battery with liquid electrolyte in the event of a decrease in the volume of electrolyte in a given cell. In some embodiments, the flow regulating elements may be arranged vertically above the overflow portion.

[0018] Also disclosed herein is an energy storage method. The method may include receiving electrolyte in the electrolyte supply tank and allowing, if an electrolyte supply tank overflow occurs, some part of the electrolyte flows from the electrolyte supply tank to the underlying cell; and allowing, if an overflow occurs in the underlying cell to allow some of the electrolyte to flow from the first cell into the second cell or into the receiving tank. This electrolyte cascade effect ensures that the electrolyte levels in all cells are approximately equal and full. This can help maintain good electrical contact and approximately the same and equal electrolyte volumes even when expanding, contracting or evaporating the electrolyte.

[0019] Additional methods are also described herein. The method of storing electricity may include providing one or more bipolar electrodes contacting the air and the airspace between them. The connection of an electrode in contact with air from one cell connected with a metal electrode from another cell - can be referred to as "centroid". The "Centroid" consists of a metal electrode (generally, an anode) from one cell in electrical contact with the electrode contacting the air from the other cell. This allows an air channel to be provided between the metal electrode and the air contacting electrode. On top of one or more of these centroid extends the housing, and below these centroid extends the other housing. The first cell covers the space above the metal electrode and is surrounded by the first housing to receive liquid electrolyte. The second cell includes the space below the electrode in contact with the air closed by the second space to receive the electrolyte. In some embodiments, a centroid may be provided as described herein or illustrated elsewhere.

[0020] An industrial scale energy storage system is also described herein, which may include multiple cells containing at least one housing, where air ducts are provided between the individual links; electrolyte flow management system, which is configured to distribute the electrolyte to one or more cells or stacks of cells; and an airflow assembly configured to provide airflow through one or more air channels. In some embodiments, the electrolyte management system can be integrated into one or more enclosures.

[0021] Other objects and advantages of the invention will be more readily understood and understood when considered in conjunction with the following description and accompanying drawings. While the following description may include specific details describing specific embodiments of the invention, this should not be construed as limiting the scope of the invention, but rather as exemplary representation of potential or preferred forms. For each aspect of the invention, different variants are possible, as suggested herein, that are known to those of ordinary skill in the art. Various changes and modifications can be made within the scope of the invention without departing from its spirit.

[0022] Also disclosed is an electrically rechargeable metal anode cell or battery containing a metal electrode, an air contacting electrode; and an aqueous electrolyte placed between the metal electrode and the air contacting electrode in which the metal electrode is in direct contact with the liquid electrolyte and without ionically conductive and electrically insulating material between the air contacting electrode and the liquid electrolyte.

[0023] Certain embodiments provide a cell or battery that includes a housing supporting both a metal electrode and an air contacting electrode such that the metal electrode and the air contacting electrode are at a constant distance from each other. For example, the constant distance between the metal electrode and the air contacting electrode creates a space in which liquid electrolyte can be contained. In other examples, the housing is made at least partially of polymer material or plastic. In addition, in some examples, the housing includes a shelf that protrudes inside the battery or cell and which is in contact with the metal electrode.

[0024] In some embodiments, the metal electrode comprises zinc. In others, the metal electrode contains magnesium.

[0025] In some embodiments, the air contacting electrode comprises a matrix comprising carbon or a polymer; air-permeable hydrophobic membrane; and a corrosion resistant, electrically conductive collector.

[0026] In some embodiments, the current collector comprises a conductive material comprising expanded metal mesh, conductive shutter, fabric, foam, sheet, wire, shell, rod, wool, or any combination thereof. In some examples, the current collector contains one or more electrically conductive polymers.

[0027] In some embodiments, the evolution of gas in the form of oxygen is conducive to charging the cell or battery.

[0028] In some embodiments, the metal compound changes its oxidation state and forms a catalytic material that promotes the evolution of oxygen gas during the charging of the cell or battery.

[0029] In some embodiments, the air contacting electrode and the metal electrode are connected in a bipolar configuration. In others, the electrode contacting the air is in a horizontal position and is located above the metal electrode.

[0030] Some embodiments further include an auxiliary electrode configured to charge the cell and associated oxygen formation, which is positioned between the air contacting electrode and the metal electrode, or on both sides of the metal electrode. [0031] In some embodiments, the air contacting electrode comprises carbonaceous material. For example, an air contacting electrode comprises one or more of the following: soot, acetylene soot, thermal or furnace soot, channel soot, activated carbon, graphite, pyrolytic graphite, reticulated vitreous carbon, fluorinated carbons or vitreous carbon. In other examples, the air contacting electrode comprises carbon-based particles of various shapes and sizes that include one or more of the following: carbon nanotubes, functionalized nanotubes, carbon nanofibers, functionalized nanofibers, wires, flakes, foil, graphene or fullerenes . In addition, in some examples, the air contacting electrode comprises at least one carbon based component, wherein the resistivity of the air contacting electrode is less than 60 ohm-cm.

[0032] In other embodiments, the air contacting electrode comprises at least one carbon based component, wherein the porosity of the air contacting electrode is greater than 30%.

[0033] In some embodiments, the air contacting electrode comprises at least one electrically conductive carbon-based polymer.

[0034] Some embodiments further include a binder that provides the air contacting electrode with a tensile strength greater than about 0.137 bar (2 pounds / inch)²).

[0035] In some embodiments, the air contacting electrode comprises at least one non-carbon material.

[0036] In alternative embodiments, the air contacting electrode comprises at least one metal or non-metal oxide. For example, an air contacting electrode contains one or more metal oxides that are non-stoichiometric and have the formula Mm-xOm-y, where M is metal, O is oxygen, subscript x is 0 <x <1, subscript y has the value 0 <y <1 and the subscript m can be 1 <m <5. In other examples, the air contacting electrode comprises one or more metal or non-metal oxides belonging to the group selected from: PtO2, NiO2, Nb2Os, MOO3, ZnO2, SnO2, Fe2O3, W2O3, Al2O3, Bi2O3, Yb2O3, Ge2O3, B2O3 or CeO 2. In addition, in other embodiments, the air contacting electrode comprises doped or undoped silicon. For example, the air contacting electrode comprises one or more of the following: SiO2, aluminosilicate, ultramarine blue or Al2O3.

[0037] In some embodiments, the air contacting electrode comprises a sulfur compound. In addition, in some cases, the sulfur compound includes sulfide (e.g., SnS or TiS2).

[0038] In other embodiments, the air contacting electrode comprises a carbide of one or more of the following: metal, non-metal, or transition metal. For example, an air contacting electrode includes one or more of the following: TiC, VC, WC or BC.

[0039] In some embodiments, the air contacting electrode comprises a boride of one or more of the following: metal, non-metal or transition metal. For example, the air contacting electrode contains TiB2.

[0040] In some embodiments, the air contacting electrode comprises one or more of the following: metal, non-metal or transition metal. For example, an air contacting electrode contains one or more of the following elements: Ir, Zr, Ti, Pt, Ru, Rh, Co, Mn, V, Ce, Bi, Ag, Cu, Fe or Au. In other examples, the air contacting electrode comprises nanoparticles containing one or more of the following elements: Ir, Zr, Ti, Pt, Ru, Rh, Co, Mn, V, Ce, Bi, Ag, Cu, Fe or Au.

[0041] In some embodiments, the air contacting electrode comprises TiH2.

[0042] In some embodiments, the air contacting electrode comprises one or more metal oxides or transition metals. For example, an air contacting electrode contains one or more compounds including titanium and oxygen. In other examples, the air contacting electrode comprises one or more of the following: TiO2, Ti4O7, Ti5O8 or Ti5O9. In addition, in some examples, the air contacting electrode comprises nanometric particles comprising one or more of the following: TiO2, Ti4O7, Ti5O8 or Ti5O9.

[0043] In some embodiments, the air contacting electrode comprises one or more titanium compounds in which titanium has an average oxidation number of 4.0 or below. For example, an air contacting electrode contains one or more titanium compounds in which titanium has an average oxidation number between 3.5 and 4.0. In other examples, the air contacting electrode contains one or more titanium compounds in which titanium has an average oxidation number between 3.2 and 3.5.

[0044] In some embodiments, the air contacting electrode comprises one or more vanadium and oxygen containing compounds. For example, the air contacting electrode comprises one or more of the following vanadium compounds: vanadium (II) oxide, vanadium (III) oxide, vanadium (IV) oxide or vanadium (V) oxide. In addition, in some examples, the air contacting electrode comprises one or more vanadium and oxygen containing compounds in which the vanadium oxidation degree has an integer value in the range between 5.0 and 3.0. In alternative examples, the air contacting electrode comprises V6O13 or V5O8.

[0045] In some embodiments, the air contacting electrode comprises one or more manganese compounds in which the manganese has an oxidation state of 4.0 or below. For example, an air contacting electrode contains one or more manganese compounds in which the manganese is on an average oxidation state between 3.5 and 4.0. In other examples, the air contacting electrode comprises one or more manganese compounds in which the manganese is on an average oxidation state between 3.0 and 3.5. In addition, in some examples, the air contacting electrode comprises one or more manganese compounds in which the manganese has an average oxidation state of between 2.5 and 3.0.

[0046] In some embodiments, the air contacting electrode comprises one or more of the following: MnO2, Mn3O4, Mn5O8 or MnOx, wherein the subscript x is in the range 1.10 <x <2.01.

[0047] In some embodiments, the air contacting electrode comprises nanometric particles containing one or more manganese compounds, wherein the manganese is on an average oxidation state between 3.0 and 3.5.

[0048] In some embodiments, the air contacting electrode comprises one or more compounds including metal or transition metal and oxygen. For example, the air contacting electrode comprises one or more of the following: IrO2, RuO2, V2O5, CeO2 or RhO2. In other examples, the air contacting electrode comprises nanometric metal oxide particles comprising one or more of the following: IrO2, RuO2, V2O5, CeO2 or RhO2.

[0049] In some embodiments, the air contacting electrode comprises metal alloys or combinations of metals and metal alloys.

[0050] In some embodiments, the air contacting electrode comprises intermetallic mixed metals.

[0051] In some embodiments, the air contacting electrode includes one or more of the following: Ag-Ni; Ag-Au; PdPt; Pt0,5Au0,5; PtxY1-x where Y is selected from the group consisting of cobalt, nickel, vanadium, copper, iron, chrome, palladium, titanium, tungsten, aluminum, silver, copper, gold or combinations thereof ax is between 0.1 and 0.9; or PtxMzY1-xz, wherein M is selected from the group consisting of iridium, rhenium, cobalt and nickel and combinations thereof, Y is selected from the group consisting of cobalt, nickel, vanadium, copper, iron, chrome, palladium, titanium, tungsten, aluminum, silver, copper, gold or combinations thereof ax + z is between 0.1 and 0.9.

[0052] In some embodiments, the air contacting electrode comprises one or more metal based cyclic ring compounds that contain nitrogen groups. For example, an air contacting electrode contains porphyrin containing one or more metals or products of thermally or radiation induced decomposition of porphyrin containing one or more metals.

[0053] In some embodiments, the air contacting electrode comprises a cyclic compound or ring complex. For example, the air contacting electrode contains tetraazaazulene.

[0054] In some embodiments, the air contacting electrode comprises cobalt or a compound thereof.

[0055] In some embodiments, the air contacting electrode comprises nickel or a compound thereof.

[0056] In some embodiments, the air contacting electrode comprises nanometric transition metals.

[0057] In some embodiments, the air contacting electrode comprises a plurality of cobalt particles having an average diameter less than 1 micron.

[0058] In some embodiments, the air contacting electrode comprises one or more transition metal oxides, carbides, or borides, further comprising an electrically conductive additive.

[0059] In some embodiments, the air contacting electrode comprises manganese oxide and an electrically conductive additive. For example, the air contacting electrode contains manganese oxide and electrically conductive carbon.

[0060] In some embodiments, the air contacting electrode comprises manganese oxide and a plurality of conductive metal-containing particles.

[0061] In some embodiments, the air contacting electrode comprises manganese oxide having the general formula AaMnxMyOzSsHh; where A is selected from H, Li, Na, K, Rb,

Sr or Ag; the subscript a is 0.00 <a <1.2; Mn means manganese; M is selected from V, Ce, Bi, Ti, Fe, Co, Ni, Zr, La, Yb; O is oxygen; S is sulfur; the subscript s is 0.00 <s <0.1; H is selected from F or Cl; the subscript h is 0.00 <h <0.15; and the subscripts x, y and z are such that the entire compound is electrically neutral.

[0062] In some embodiments, the manganese compound comprises a crystallographic phase selected from: alpha, beta or gamma MnO2.

[0063] In some embodiments, the manganese compound comprises an amorphous phase.

[0064] In some embodiments, the air contacting electrode comprises cobalt oxides. For example, the air contacting electrode contains cobalt and oxygen, with cobalt having an oxidation number of +2 to +8. In other examples, the air contacting electrode comprises one or more of the following: CoO, CoO3, CoO4, or Co3O4. In addition, in some examples, the air contacting electrode comprises a plurality of particles containing CoO, CoO3, CoO4 or Co3O4 and having an average particle diameter less than 1 micron.

[0065] In some embodiments, the air contacting electrode comprises PbMnOx where Pb is lead, Mn is manganese, and the subscript x is a number such that the compound is electrically neutral.

[0066] In some embodiments, the air contacting electrode comprises one or more compounds having a stable combination of transition metal, oxygen and lanthanide. For example, an air contacting electrode contains a plurality of particles of one or more compounds having a stable combination of transition metal, oxygen and lanthanide, wherein the particles have an average diameter less than 1 micron. In other examples, the air contacting electrode comprises LaMnO3. In addition, in some examples, the air contacting electrode comprises LaMnO3 nanoparticles.

[0067] In some embodiments, the air contacting electrode comprises a compound having the general formula LaMxMnyO, in which La is lanthanide, M is metal, Mn is manganese, O is oxygen, and the subscripts x, y and z are numbers such that the compound is electrically stable. For example, an air contacting electrode includes one or more of: LaNi0.5Mn0.5O3, LaCu0.5Mn0.5O3, La0.8Sr0.2MnO3, La2 / 3Ca1 / 3MnO3 or La1 / 2Sr1 / 2MnO3. In other examples, the air contacting electrode contains nanoparticles: LaNi0,5Mn0,5O3, LaCu0,5Mn0,5O3, La0,8Sr0,2MnO3, La2 / 3Ca1 / 3MnO3 or La1 / 2Sr1 / 2MnO3.

[0068] In some embodiments, the air contacting electrode comprises a transition metal, an alkali or alkaline earth metal and a phosphate group having the general formula AxMyPOz in which A is an alkali or alkaline earth metal, M is a transition metal and the subscripts x and y are with numbers such that the relationship is stable and the subscript z is approximately 4.

[0069] In some embodiments, the air contacting electrode comprises LiMnPO4, LiCoPO4 or LiFePO4. For example, an air contacting electrode contains nanoparticles: LiMnPO4, LiCoPO4 or LiFePO4.

[0070] In some embodiments, the air contacting electrode comprises a compound having a combination of lanthanide, metal, transition metal oxide and halogen, with the general formula MnxMyAzOaHb, in which Mn is manganese, M is a transition metal, and A is an alkali or alkaline earth metal, O is oxygen, H is halogen, and the subscripts x, y, a and b are values ​​such that this compound is electrically stable.

[0071] In some embodiments, the air contacting electrode comprises nanoparticles of a compound having a combination of lanthanide, metal, transition metal oxide and halogen, with the general formula MnxMyAzOaHb, in which Mn is manganese, M is a transition metal, A is an alkali or alkaline earth metal , O is oxygen, H is halogen, and the subscripts x, y, a and b are values ​​such that this compound is electrically stable.

[0072] In some embodiments, the air contacting electrode comprises a compound that undergoes electrochemical reduction or oxidation, thereby providing an additional voltage plateau or additional capacity during electrical discharge. In some examples, this compound is one that, by undergoing electrochemical reduction or oxidation, effectively reduces the required cell charging potentials or increases the potential during cell discharge.

[0073] In some embodiments, the compound in the vicinity of the air contacting electrode is reduced when the cell is discharged and is reoxidized by means of an oxidizing agent or oxidizing surface, or present in a battery or cell, or introduced into a battery or cell from an external sources. In some cases, the oxidizing agent is oxygen or hydrogen peroxide. In others, the oxidizing agent is N2O or ammonium nitrate. In addition, in some cases, the oxidizing agent is a transition metal compound dissolved in the electrolyte.

[0074] In some embodiments, the battery or cell is configured to undergo one or more electrode reactions with one or more of urea, nitrate, chloride or ammonia. For example, the battery or cell is configured to undergo one or more electrode reactions with at least one of: chlorine, oxygen, hypochlorite or chloride.

[0075] In some embodiments, the current collector of the air contacting electrode is made of electrically conductive polymer.

[0076] In some embodiments, the current collector of the air contacting electrode is made of metal. For example, the current collector of the air-contacting electrode is made of titanium metal or an alloy thereof.

[0077] In some embodiments, the current collector of the air contacting electrode is made of titanium metal or titanium alloys coated with a corrosion resistant coating. For example, the current collector of the air contacting electrode is made of titanium metal or titanium alloys coated with one or more of the following: TiN, TiC, Ti, TiB2 oxycarbide, Ti2S3, NiB, CrN, pyrolytic graphite, conductive polymer or glassy carbon. In other examples, the current collector of the air contacting electrode is made of titanium coated with TiO2 and / or its suboxides. In some examples, the current collector of the air-contacting electrode is made of titanium or TiO2 coated alloys thereof and has been given better electrical conductivity by means of additives or admixtures.

[0078] In some embodiments, the current collector of the air contacting electrode is coated with an oxygen reduction or water oxidation catalyst. For example, the current collector of the air-contacting electrode is first coated with a suitable protective coating and then coated with a suitable oxygen reduction or water oxidation catalyst. For example, the current collector of the air contacting electrode contains titanium coated with an oxygen reduction or water oxidation catalyst. In other examples, the current collector of the air contacting electrode comprises a titanium coated with a protective coating and then coated with an oxygen reduction or water oxidation catalyst.

[0079] In some embodiments, the current collector of the air-contacting electrode is in the form of an electrically conductive shield, perforated film, fabric, wire, mesh or porous foam. For example, the current collector of the electrode contacting the air occurs in the form of an electrically conductive shield and is a composite containing metal and glassy carbon or graphite.

[0080] In some embodiments, the electrolyte comprises an aqueous chloride-based electrolyte. For example, the electrolyte includes a mixture of soluble chloride salts whose cations are suitable for forming soluble chloride salts in solution. In other examples, the electrolyte is an aqueous chloride-based electrolyte having a pH in the range of from about 3 to about 10. In addition, in some examples, the electrolyte is an aqueous chloride-based electrolyte having a conductivity greater than 30 (millimeters cm)^-1. In alternative examples, the electrolyte is an aqueous chloride-based electrolyte having a ratio [Cr] to [Zn ++] of 2 or more. In addition, in some examples, the electrolyte is an aqueous chloride-based electrolyte having ratios [Cl^-] to [Zn ++] of 3 or more. In other examples, the electrolyte is an aqueous chloride-based electrolyte having a ratio [Cr] to [Zn ++] of 5 or more.

[0081] In some embodiments, the electrolyte comprises a mixture of soluble salts based on at least one of the following anions: sulfates, nitrates, carbonates, hexafluorosilicates, tetrafluoroborates, methanesulfonates, permanganates, hexafluorophosphates, borates, fluorides or phosphates.

[0082] In some embodiments, the pH level of the electrolyte is such that CO2 normally present in the air is not absorbed by the electrolyte and little or no carbonates are formed.

[0083] In some embodiments, the electrolyte further comprises an additive or additive combination that improves the deposition of zinc during metallization (cell charging) on ​​a metal electrode. For example, the electrolyte further comprises an additive that includes at least one of the following: polyethylene glycols or thiourea.

[0084] In some embodiments, the electrolyte further comprises an additive that prevents the electrolyte from foaming and allows the release of any gas produced.

[0085] In some embodiments, the electrolyte contains an additive that includes one or more of the following: Simethicone, Dowex, Aloe Vera, Emulphogen, sodium dodeculfate, sulfonated castor oil, rosins, or other surfactants. [0086] In some embodiments, the electrolyte contains an additive that prevents the evolution of hydrogen during charging.

[0087] In some embodiments, the electrolyte comprises an additive that includes one or more of the following high voltage hydrogen chloride salts: tin chloride, tin nitrate, lead chloride, lead nitrate, mercury chloride, cadmium chloride, cadmium nitrate, bismuth nitrate, indium nitrate, indium chloride or bismuth chloride.

[0088] In some embodiments, the electrolyte contains an additive that prevents or minimizes the evolution of chlorine gas and / or hypochlorite during cell charging.

[0089] In some embodiments, the electrolyte comprises an electrolyte additive comprising urea.

[0090] In some embodiments, the electrolyte contains an additive that promotes the desired zinc plating or precipitation of zinc.

[0091] In some embodiments, the electrolyte contains an additive that promotes the formation of zinc deposits that have an electrochemical surface area at least two times the geometric surface area of ​​the electrode.

[0092] In some embodiments, the electrolyte comprises an additional anion comprising at least one of the following anions: benzoates, iodates, stearates, nitrates, citrates or carbonates. For example, the electrolyte contains an additive containing an anion with a pKa of 2 to 11.

[0093] In some embodiments, the electrolyte comprises a soluble manganese salt.

[0094] In some embodiments, the metal electrode further comprises a current collector formed of a metal coated with a protective or conductive coating. For example, the metal electrode further includes a current collector formed of a titanium metal with a protective coating of one or more of the following: TiC, TiN, CrN, TiB2, NiB, pyrolytic carbon, or a conductive polymer.

[0095] Also disclosed is a battery assembly including a first cell having a metal electrode, an air-contacting electrode and the electrolyte therebetween; and a second cell having a metal electrode, an electrode in contact with air and an electrolyte between them, where the metal electrode of the first cell is in contact with the electrode contacting the air of the second cell in such a way, that an air channel is formed between the metal electrode of the first cell and the electrode contacting the air of the second cell, and where both the metal and air contacting electrodes are substantially horizontally oriented.

[0096] In some embodiments, the metal electrodes and the air contacting electrodes are located substantially in a horizontal position.

[0097] In some embodiments, the metal electrode of the first cell is in contact with the electrode contacting the air of the second cell by means of a mechanical clamp around the edge of the electrode contacting the air of the first cell, thereby forming a centroid.

[0098] In some embodiments, the centroid provides a serial connection between the first link and the second link.

[0099] In some embodiments, the first cell, second cell, and one or more cells are substantially horizontally oriented and arranged in series in parallel so as to obtain the desired voltage and provide the desired current density.

[0100] In some embodiments, the gas flows in a horizontal direction in the air channel. [0101] Some embodiments further include a third cell having a metal electrode, an air-contacting electrode and the electrolyte therebetween; and the fourth cell having a metal electrode, an electrode in contact with air and an electrolyte between them, where the metal electrode of the third cell is mechanically clamped around the edge of the electrode contacting the air of the fourth cell in such a way, that an air channel is formed between the metal electrode of the third cell and the electrode contacting the air of the fourth cell, thus creating a second centroid, and where the second centroid is in electrical contact with the first centroid, thus providing an electrical connection between the first link and the second link.

[0102] Also disclosed is an energy storage system comprising an electrolyte supply assembly having a flow control element configured to evenly distribute liquid electrolyte to underlying metal-air cells; and one or more metal anode links comprising at least one common fill or drain connection having a liquid overflow portion, where the function of the flow control element is arranged vertically above the overflow portion.

[0103] In some embodiments, the flow regulating element breaks the liquid electrolyte into discrete and discrete droplets.

[0104] In some embodiments, one or more metal anode cells are horizontally oriented and stacked on top of each other.

[0105] In some embodiments, the filling or drain connections of each individual cell with a metal anode in the battery stack are oriented and stacked on top of each other, thereby creating a continuous vertical flow channel for fluid to move.

[0106] In some embodiments, the energy storage system further includes a liquid electrolyte collecting tray disposed under one or more metal anode cells. [0107] In some embodiments, the electrolyte supply assembly for delivering liquid electrolyte to individual cells is gravity driven.

[0108] In some embodiments, the physical structure of the electrolyte delivery assembly is injection molded.

[0109] In some embodiments, a plurality of separate metal anode links are stacked together under pressure.

[0110] In some embodiments, the multiple horizontally oriented metal anode cells are slightly inclined near the electrolyte supply assembly.

[0111] In some embodiments, the metal anode links are inclined upwards at an angle of 1 to 5 degrees from horizontal.

[0112] Also disclosed is an energy storage method comprising: receiving liquid electrolyte into an electrolyte supply tank; enabling, if liquid electrolyte overflows from the electrolyte supply tank, dripping the liquid electrolyte down into underlying metal anode cells; and enabling if there is further overflow of liquid electrolyte in the cells underneath with a metal anode, dripping a certain portion of the electrolyte down to the second level of the underlying metal anode cells or to the receiving tank located below the metal anode cells.

[0113] Some embodiments further include: removing liquid electrolyte from the receiving tank; treating the liquid electrolyte from the receiving tank; if necessary, adding additional components to the liquid electrolyte; and, if necessary, supplying fresh or treated liquid electrolyte to the electrolyte supply tank.

[0114] In some embodiments, the first metal anode cell and the second metal anode cell are electrically connected together in series.

[0115] In some embodiments, the first metal anode cell and the second metal anode cell have an air gap between them.

[0116] Also disclosed is an energy storage method comprising: providing one or more centroid having a metal electrode of a first cell in contact with an electrode contacting the air of the second cell, where a channel or airway is provided between the metal electrode and the air contacting electrode; and providing a first enclosure extending over one or more centroid and a second enclosure extending below one or more centroid, where the first cell covers the space above the metal electrode and surrounded by the first housing to receive the electrolyte, and the second cell includes a space under the electrode contacting the air surrounded by the second space to receive the electrolyte.

[0117] A battery stack configuration has also been disclosed comprising the arrangement of a plurality of cells arranged vertically stacked and horizontally adjacent, where the individual cells comprise a metal electrode and an air contacting electrode, and where the arrangement of the multiple cells allows electrical connections between the cells both vertically and vertically and horizontally, thus bypassing the damaged link.

[0118] In another aspect of the present invention, an industrial scale energy storage system is provided comprising: a plurality of horizontally arranged and vertically stacked cells with a metal anode containing at least one housing, where one or more air channels are provided between the cells; electrolyte flow management system, integral with one or more housings, configured to automatically distribute liquid electrolyte into the cells; and an airflow assembly configured to provide airflow through one or more channels or pathways.

BRIEF DESCRIPTION OF THE DRAWINGS [0119] Various new features of the present invention are set out in detail in the appended claims. A better understanding of the features and advantages of the present invention will be achieved by reference to the following detailed description, which sets forth illustrative forms in which the principles of the invention are applied and the accompanying drawings in which:

FIG. 1 shows rechargeable metal anode cells arranged in a horizontal orientation according to an embodiment of the invention. For each individual cell, the aerated, porous cathode can be oriented horizontally (on top), while the metal anode is horizontally (bottom). Liquid electrolyte may be contained between the aerated cathode at the top and the metal anode at the bottom. The plastic housing can tightly hold both the cathode and anode tightly in place, and can prevent liquid electrolyte from leaking from these cells. This arrangement of electrodes does not require a separation membrane between the cathode and anode. The open area or air space provided between each individual cell in the multi-cell assembly allows for free air flow in the space between these cells. While air flows between these cells, it can supply oxygen (fuel) to the porous aerated cathode that faces the airspace.

FIG. 2 shows an example of individual cells that can be stacked on top of each other. The individual cells are held together by an electrically insulating plastic housing.

FIG. 3 is an isometric view of a single cell in accordance with an embodiment of the invention. The plastic cover can hold individual electrodes.

FIG. 4A shows a system for maintaining a substantially constant and uniform electrolyte level in a group of cells that are arranged horizontally, where these cells can share a common electrolyte filling connection and a recirculation tank according to an embodiment of the invention.

FIG. 4B shows an additional system for maintaining electrolyte levels within a number of cells with adjacent cells in one plane having a common filling connection and which may contain a separate tank or loading device, where the used electrolyte can be replaced with a charged electrolyte (with metallic zinc or zinc suspension ) in accordance with another embodiment of the invention.

FIG. 5 shows an example of battery stack configuration.

FIG. 6 shows an example of a centralized electrolyte management connection for an energy storage system that allows each cell to be filled with liquid electrolyte. Excess electrolyte from one cell may cascade or overflow in a controlled manner to other cells located below in accordance with the embodiment of the invention.

FIG. 7 shows an additional view of the battery stack configuration with vertical metal electrode and air contact electrode connections as well as horizontal redundancy to allow the damaged cell to be bypassed.

FIG. 8A shows an example of an insulated cargo container and the use of an HVAC device for a battery module with a separate stack of shelves with an upper electrolyte storage tank and a lower drain being part of the electrolyte recirculation system in accordance with the embodiment of the present invention.

FIG. 8B depicts individual cell shelves at the bottom of battery modules with pipes that are part of a recirculation system on the container floor in accordance with the embodiment of the present invention.

FIG. 8C presents a series of battery modules assembled into a battery system with recirculation tanks, inverters or other power control devices.

FIG. 8D shows a top view of a battery system comprising a plurality of battery modules inside a container.

Figure 8E provides one example of an airflow assembly.

Figure 8F provides an additional view of the airflow assembly.

FIG. 8G provides an alternative example of an airflow assembly.

FIG. 8H provides one example of a battery system inside a container.

FIG. 9A provides a bottom view of the cell housing assembly or shelf with electrical connections at the end of each row that are horizontally connected.

FIG. 9B shows the cell case or shelf assembly with one or more centroid.

FIG. 10 provides a top view of four flat links arranged horizontally so as to share a common fill and outlet connection. These four, tiled links in a horizontal arrangement can be referred to as "four".

FIG. 11A shows a top view of an energy storage system with a common, shared fill and overflow connection between cells in accordance with an embodiment of the invention.

FIG. 11B shows a side view or cross-section of the energy storage system of FIG. 11A. Here, each four-cell four can be slightly tilted upwards to more easily allow any gas produced to "bounce" and release easily. Gravity helps the flow of water or liquid electrolyte from the supply of water or the electrolyte tank located above the cells to the individual cells located below.

FIG. 12 provides a schematic diagram of the structure with three electrodes for an electrically charged metal anode cell.

FIG. 13 shows an example of cell voltage as a function of time during testing in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION [0120] Although preferred embodiments of the invention have been shown and described herein, it will be apparent to those skilled in the art that such forms are provided by way of example only . Numerous variants, changes and replacements will now be available to those skilled in the art without departing from the spirit of the invention. It should be understood that the various alternatives described herein for the embodiments of the invention may be used in the practice of the invention.

[0121] The invention provides electrically charged metal anode cells and methods for connecting individual cells into battery systems. The various aspects of the invention described herein can be used for any of the specific applications set forth below, or for other types of battery systems. The invention can be used as a separate system or method, or as part of a network / industrial system or system or method for storing renewable energy. It should be understood that various aspects of the invention may be considered individually, collectively, or in combination with each other.

AND. Metal-Air Battery [0122] Metal anode batteries may include any number of battery systems that use a metal anode and a suitable cathode. An anode in a cell is an electrode where oxidation or loss of electrons occurs. The cathode in the cell is the place where these electrons are reduced or received. The cathode may contain materials that undergo electrochemical reduction by themselves. The cathode may also provide a surface or porous structure, where appropriate compounds may be reduced. As an example, the oxygen from the ambient air can be reduced on suitable catalytic or high surface area substrates. Metal-air batteries have the potential to achieve very high energy density at low costs. Accordingly, one aspect of the present invention provides a metal anode battery system that uses readily available atmospheric oxygen as a cathode reagent. Metal-air batteries are unique energy sources because one of the reagents, oxygen gas, is not stored inside the battery itself. Instead, oxygen gas, which makes up about 20 percent of the ambient air, can be taken from an unlimited amount of ambient air as needed and can get into the cell where it is reduced by means of catalytic surfaces inside the electrode contacting the air. Oxygen gas can be considered as an inexhaustible cathode reagent. Because one of the cell's reactants, oxygen gas, does not need to be stored inside the cell, special features such as total cell weight, volume or dimensions can be relatively small, and energy densities (cell capacities in ampere-hours per cell mass) can be higher than other electrochemical energy storage systems. Another advantage is the small volume and mass occupied by porous electrodes that come into contact with air. This weight and volume advantage results in better system characteristics (ampere hour / kilogram and ampere hour / liter) compared to other electrochemical energy sources.

[0123] Aerated battery systems generate electricity by electrochemically coupling the oxidation reaction on a reactive metal electrode, which acts as an anode (discharges the electrons) along with the oxygen reduction reaction (electron intake) on the porous electrode that contacts the air when the cell is discharged. The air contacting electrode may be a sheet-like element with opposing surfaces properly exposed to the atmosphere and the aqueous electrolyte of the cell. During the operation of the cell, oxygen is reduced inside the cathode, while the metal anode is oxidized, providing a useful flow of electrical current through an external circuitry connected between the anode and cathode. In some embodiments of the present invention, the air cathode may be air permeable, but substantially impermeable to the aqueous electrolyte, and may include an electrically conductive element to which an external circuitry may be connected. In one embodiment, the air cathode comprises a conductive material (e.g. carbon), an additional catalyst supporting oxygen dissociation, a hydrophobic polymeric material (e.g., finely divided polymeric material) and an optional electrically conductive element for receiving electric current, i.e. current collector.

[0124] In some embodiments, the current collector may include any type of conductive material in any suitable shape or configuration including, but not limited to: expanded metal mesh, screens, fabrics, foams, sheets, wires, shells, rods, wool or any of them connections.

[0125] In other embodiments, the anode contains zinc material (e.g., free zinc, its oxide, its alloy, or any combination thereof).

[0126] In some embodiments, the air contacting electrode comprises a suitable amount of one or more oxygen reduction catalysts. The free electrons produced from the zinc anode (oxidation) can travel through an external load to the porous air-contacting electrode, where these electrons are absorbed by the reduction reaction, thus completing the electrical circuit.

[0127] However, a key disadvantage of this type of metal / air accumulator may be that they are usually not electrically rechargeable after a large number of discharge and charge cycles. The discharge-charge cycle is defined here as one full electric discharge followed by a full electric charge. In some embodiments, a full electrical discharge can last about 6 hours, while a subsequent full charge can also last about 6 hours. This 12 hour discharging and charging cycle (with the possibility of shorter charging and discharging times to stabilize or regulate industrial electrical networks) can be characteristic and expected for a typical one full day of standby electricity service. The electric recharging capability may be necessary or highly desirable for any battery to be considered for use in electrical networks on an industrial scale. Traditional large-scale metal-air batteries are either not capable of being electrically charged at all or may only be subjected to less than a few hundred discharge and charge cycles. In addition, traditional large metal-air battery systems are not readily available on the market. To be practical in industrial applications, an electrically charged battery should provide at least 3,500 to 10,000 high-efficiency discharge and charge cycles with generally good charge / discharge performance. This corresponds to about 10 to 30 years of age.

[0128] Inside metal-air accumulators, the electrically conductive electrolyte connecting the metal electrode and the air contacting electrode is usually a liquid solution (in some forms based on water, aqueous) containing dissolved salts. Metal-air accumulators can be considered as a combination of desirable properties for both fuel cells and accumulators: metal (e.g. zinc) is a fuel, reaction rates can be adjusted by changing the air flow, and oxidized metal / electrolyte paste can be replaced with fresh metal or paste. The great benefit of metal-air cell safety is that they are inherently short-circuit proof. Because metal-air cells are limited by the amount of oxygen they can draw and use from the surrounding air, they are ultimately limited in the amount of current they can produce. When a short circuit occurs inside the cell, unlike other battery chemistry, the metal-air cell simply will not provide unlimited current - the current delivery capacity will have a maximum upper limit. This is important from a security point of view. Metal-air battery systems may include, but are not limited to, aluminum-air, magnesium-air, iron-air, lithium-air, sodium-air, titanium air, beryllium air, and zinc-air.

[0129] Zinc, in particular, has a number of advantages over other metals. It is important to emphasize that any of the forms discussed elsewhere herein may also be used in any type of metal anode battery system that may or may not contain zinc. Any reference to zinc as the anode can also be applied to any other suitable metal and vice versa. All references to zinc-air or zinc anode batteries can be used for any other metal / air battery or metal anode system. In addition, reference to water or an aqueous electrolyte does not limit the discussion to only water or water based systems. All modifications discussed herein can be easily applied to other suitable liquids and / or electrolytes.

[0130] Zinc can be a preferred material for the battery anode because it is light, non-toxic, cheap, readily available, and exhibits high electrochemical reaction rates when plating during electrochemical charging. For this reason, zinc anode cells were used as primary cells (for disposal) and recharged (reusable). Zinc anode cells can be charged mechanically or electrically. In mechanically recharged (re-fueled) cells, spent zinc can be physically removed from the cell / battery and mechanically replaced with fresh metallic zinc. Used zinc can be processed separately elsewhere back to metallic zinc. In some embodiments, such mechanically charged batteries can be used in storage network applications.

[0131] In preferred embodiments, rechargeable cells or battery cells can be used. In more practical electrically charged cells, electricity from an external source can be applied to the cell or battery, and this electricity can be converted and stored as potential chemical energy inside the cell or battery. In one type of rechargeable cell, such as a zinc-air cell, when electricity from an external source is supplied to the cell, the water in the aqueous electrolyte is oxidized (loses electrons) to produce oxygen gas in the porous electrode that contacts the air, while zinc ions in the solution can be re-deposited electrochemically (plated) back onto the metal electrode as metallic zinc. During electrochemical charging, the electrochemical processes that occur during cell discharge are reversed and the original chemical compounds are regenerated and regenerated. When charging the cell, the zinc electrode, which was an anode when the cell was discharged (lost electrons), now becomes a cathode (or an electrode that now gains electrons). The air-contacting electrode that acted as a cathode (and gained electrons) during the discharge of the cell now functions as an anode (where water loses electrons and becomes oxidized) to produce oxygen gas. Typically, alkali based aqueous electrolytes are usually used in zinc anode systems. These electrolytes are based on highly corrosive, high pH solutions, such as potassium hydroxide, KOH. [0132] During normal cell operation during cell discharge, oxygen from ambient air can be reduced (gain electrons), while the reactive metal is oxidized (lose electrons). In zinc-air cells containing an alkaline electrolyte, for example, the following simplified reactions can occur:

On the anode: 2Zn + 4OH^- > 2ZnO + 2H2O + 4e^- Eo = 1.25V

At the cathode: O2 + 2H2O + 4e-> 4OH^- Eo = 0.40V

Total Reaction: 2Zn + O2> 2ZnO E (ocv) = 1.65V [0133] In some cases, the actual anode reaction products are not simply Zno + H2o, but rather Zn (oH) 4^2-. The total anode reaction can therefore be written as:

2Zn + 8OH^- > 2Zn (OH) 4^2- + 4e [0134] The resulting zinc oxidation product, potassium zincate, may remain in solution.

[0135] Zinc-air rechargeable cells that use alkaline electrolytes can have many technical problems. The first problem is that when air enters the cell, CO2, carbon dioxide (normally present in the ambient air) can also enter and react slowly with the alkaline electrolyte to form insoluble carbonates. These insoluble carbonates precipitate inside the pores of porous electrodes in contact with air as well as in the alkaline electrolyte. This formed sludge reduces the electrical conductivity of the electrolyte and because the pores of the air contacting electrode are blocked by insoluble material, the efficiency of the air contacting electrode is significantly reduced. Although carbon dioxide, CO2 absorbing systems are used to remove CO2 from the inlet air, the additional weight and complexity of such a scrubbing system reduces the advantages of metal anode systems that use an alkaline electrolyte.

[0136] Additionally, because commonly used alkaline electrolytes tend to dilute (absorbing water from the air) in humid environments, excess water can accumulate in these battery systems, causing the porous electrode in contact with air to be flooded with water. Because air (oxygen) cannot easily diffuse through water, now less oxygen can enter and be reduced inside the porous air cathode. This can cause alkaline air cathodes to quickly lose their active properties.

[0137] Another problem with traditional zinc-air alkaline cells is that although with increasing OH concentration^- ionic conductivity and cell power efficiency are improved, and the solubility of forming zinc compounds increases. This is a dilemma in the construction of links. On the one hand, higher pH (more [OH^-]) is desirable for improving the electrical conductivity of the electrolyte and good cell capacity. The compromise is that the higher electrolyte pH (more [OH^-]) can simultaneously lead to greater solubility of the forming zinc product during discharge. This can cause greater shape changes when charging the cell - applied by plating the zinc will not be deposited back in the desired morphology - thus leading to a shorter life cycle. In other words, in a typical cell design, you can choose whether the cell has good capacity with a poor life cycle or a good life cycle with poor cell capacity. The desired combination of both good life cycle and good cell capacity is currently not available for electrochemically charged cells with a metal anode.

[0138] Yet another problem regarding the use of zinc in typical alkaline electrolytes is that, when electrically charged, the zinc applied by plating tends to migrate and change in distribution on the zinc electrode. After only a few charging cycles, zinc can settle in undesirable morphologies (e.g. as spongy, mossy, filamentous or dendritic deposits). Dendritic deposits may have long pointed growths protruding beyond the normally smooth, plated metal surface. Zinc particles irregularly deposited during plating are undesirable because they usually have a higher electrical resistance and do not mechanically adhere well to each other. These zinc particles can easily peel off metal electrodes to form isolated zinc deposits. All these factors contribute to reducing the battery capacity and reducing the output power for traditional zinc-air batteries after subsequent discharge and charging cycles.

[0139] Another challenge for zinc air cells that use alkaline electrolytes is that when the cell is discharged, there is a tendency to form zinc oxide on the zinc surface. This passivating layer increases the internal resistance of the cell, and this limits discharge rates and reduces cell efficiency.

II. Battery Electrolyte [0140] In accordance with an aspect of the invention, the battery electrolyte can be selected so as to increase the performance of a metal anode battery, such as a zinc-air battery. In some embodiments, the battery electrolyte may be a chloride-based aqueous electrolyte. In some embodiments, the electrolyte may have a pH of about 6. The electrolyte may have a pH value of 10 or less, or any other pH value mentioned herein, or less. In alternative embodiments, the electrolyte may have a pH value between 3-10, 4-9, 5-7, 5.5-6.5 or 5.75-6.25. In some embodiments, the electrolyte may have a pH of about 3, 4, 5, 5.25, 5.5, 5.75, 5.8, 5.9, 5.95, 6, 6.1, 6.2, 6.3, 6.5, 6.75, 7, 8, 9 or 10. In some embodiments, the electrolyte may be alkali. The pH may be relatively neutral pH. In some embodiments, substantially no carbonates form in the air reacting with the alkaline electrolyte due to the presence of CO2. This may occur because the electrolyte in the systems and methods described herein does not contain significant amounts of hydroxide ions. This electrolyte can allow zinc plating without forming significant dendritic shapes when plating with little or no CO2 absorption.

[0141] A chloride-based aqueous electrolyte may be used in the battery provided in accordance with the present invention. Because of the lower electrolyte pH (or very low carbon dioxide), carbon dioxide is not absorbed from the air, so insoluble carbonates are not formed either in the electrolyte or in the pores of the contacting air. In addition, since aqueous chloride-based electrolytes are commonly used in the galvanizing industry to deposit smooth and well-adherent zinc deposits, galvanizing efficiency (when charging the cell) should be significantly improved.

[0142] A preferred chloride-based electrolyte in a zinc air cell is in accordance with an embodiment of the invention. The electrolyte may comprise a mixture of one or more soluble chloride salts in aqueous solution. The soluble chloride salts may have a cation suitable to form the soluble chloride salt in aqueous solution. The cations of suitable chloride salts may include zinc, ammonium, sodium or any other large or complex cations, such as ammonium or alkylammonium, which can form soluble, stable chloride salts in aqueous solutions. The conductive electrolyte can be a mixture of soluble salts based on sulfates, nitrates, carbonates, hexafluorosilicates, tetrafluoroborates, methanesulfonates, permanganate, hexafluorophosphates, borates or phosphates, either alone or mixed together in an aqueous solution. If, for example, a mixture of electrolytes with ammonium chloride and zinc is used, the new zinc-air cell can be schematically described as:

Zn / ZnCl2, NH4Cl, H2O / O2 (Carbon) [0143] In this case, reading from left to right, the zinc or corresponding zinc alloy may be an anode. The electrolyte may contain ZnCl2 and NH4Cl and H2O. A porous carbon-based electrode in contact with air is the place where O2 is reduced when the cell is discharged and where it forms when the cell is charged.

[0144] In some embodiments, various amounts of KOH or other electrolytes may be added. An CO2 scrubber additive may be required or used for such a system because the electrolyte based on potassium hydroxide absorbs CO2. Any electrolyte known in the art can be used in conjunction with forms of the systems and methods described herein.

[0145] In some embodiments, the release of oxygen can be increased by charging the cell at low current densities. Such current densities can minimize or limit the release of Cl2, which may occur when using chloride-based electrolytes. Examples of such current densities may include values ​​from about 1 mA / cm² up to about 100 mA / cm². Such current densities may be less than, greater than or between any of the following current densities: about 1 mA / cm², 5 mA / cm², 10 mA / cm², 20 mA / cm², 30 mA / cm², 40 mA / cm², 50 mA / cm², 60 mA / cm², 70 mA / cm², 80 mA / cm², 90 mA / cm² or 100 mA / cm². The oxygen release reaction can also be enhanced by adjusting the pH of the electrolyte. In addition, oxygen release can be increased by using an electrode or catalyst intentionally designed to have low oxygen release overpotential or high chlorine oxidation overpotential.

[0146] In some embodiments, the metal electrode may be made of zinc, it may be zinc plated, or it may contain zinc in any other form, such as an alloy, or deposited by plating on another metal. According to one embodiment of the present invention, the electrolyte may comprise a mixture of about 15% zinc chloride (ZnCl2) and about 15% ammonium chloride (NH4Cl) in water by mass%. The electrolyte may alternatively comprise a mixture of about 15% zinc chloride and about 20% ammonium chloride in water by weight. In some embodiments, the aqueous electrolyte may contain different amounts of zinc chloride and ammonium chloride, and may also contain other suitable salts or chlorides such as LiCl. For example, the electrolyte may contain about 10%, 12%, 13%, 14%, 14.5%, 15%,

15.5%, 16%, 17%, 18% or 20% zinc chloride or ammonium chloride. In some embodiments, the same amount or similar amounts of zinc chloride and ammonium chloride can be provided. Other materials can be added to buffer the electrolyte. These may include ammonium citrate or other compatible buffers such as ammonium acetate or ammonium hydroxide in amounts of 1 to

2% by mass.

III. Porous Air Contact Electrode [0147] A porous, structurally compact, air contact electrode (cathode) can be manufactured using any suitable carbon-based material. The right group could include soot, acetylene soot, natural or artificial graphite, active carbon, glassy carbon carbon based polymers, functionalized or non-functionalized carbon nanoparticles (defined here as having dimensions smaller than one micrometer), functionalized or non-functionalized carbon nanotubes, carbon nanofibers, fullerenes, Graphene sheets or any other suitable combination of carbon-based matrix materials or modified carbon-based materials. Functionalized carbon may mean that carbon has been modified to contain attached side groups of other compounds. Attached compounds may include functional groups (e.g. nitrogen or fluorine containing functional groups) inside the carbon structure that can be used to construct a functional porous electrode. As an example, fluorinated carbon may have the general formula CFx where the subscript x is generally less than 1.0. The cathode may be made of composites or mixtures of any of these types of carbon, with or without a suitable binder to hold these particles together. A suitable oxygen reduction or water oxidation catalyst can be added to this carbon-based cathode.

[0148] The binder as described herein may generally include a polymeric material that helps maintain electrode integrity by introducing mechanical coherence between the electrode particles themselves, and also ensures adhesion between the electrode particles and the current collector. Basically, the binder holds the electrode particles together. The binders are usually insoluble in the materials present in the battery and are generally inert in the voltage range of the cell or battery. The percentage of polymeric binder can vary from 0.1% to 25%, and preferably from 1% to 10% of the total weight of the electrode. In some cases, the percentage of binder may be greater than and / or less than one or more of the following values: 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 17%, 20%, 22% and / or 25%. Excessive binder content can reduce the gravimetric density of the cell or battery (and generally reduces electrode conductivity), while too little binder in the electrode does not provide adequate mechanical consistency.

[0149] It is possible for one or more of the above materials to perform a multi-functional role in the battery system. These materials may behave not only as auxiliary material, i.e. conductive, dispersed phase with a large surface area, but they can also act to help catalyze both oxygen reduction and water oxidation reactions. It is also possible for some of the materials contained in the air contacting electrode to actually participate in the reduction or oxidation reactions in the cell. In this way, they can help increase the cell's capacity in ampere-hours.

[0150] Examples of materials that can catalyze oxygen reduction reactions may include, but are not limited to, special carbon-based materials or selected precious metals, precious metals such as Pt, Pd, Au, Ru or Rh, or any other metals such like Mn, V, Ce,

Bi, Ag, Cu or Fe. Combinations of these metals may also be useful. Examples may include bipolar catalysts such as PdPt or PtxY1-x in which Y is selected from the group consisting of cobalt, nickel, vanadium, copper, iron, chromium, palladium, titanium, tungsten, aluminum, silver, copper, gold or combinations thereof , ax is between 0.1 and 0.9 (e.g. 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9) . Examples may also include ternary catalysts such as

PtxMzY1-xz, where M is selected from the group consisting of iridium, rhenium, cobalt, nickel or combinations thereof, Y is selected from the group consisting of cobalt, nickel, vanadium, copper, iron, chromium, palladium, titanium, tungsten, aluminum, silver, copper, gold or combinations thereof, ax + z is between 0.1 and

0.9.

[0151] Oxides of suitable precious or non-precious metals (e.g. RuO2, IrO2 or V2O5) can also be used.

[0152] Other suitable catalysts may include combinations of various precious metals, such as Pt0.5Au0.5 (PtAu).

[0153] Other suitable catalysts may include transition metals such as Mn, Fe or Co, or V-based compounds, metal oxides, doped metal oxides, mixed metal oxides, metal-based porphyrins, or any suitable combinations thereof. Suitable materials as cathode additives may also contain various metal oxides, transition metal chalcogenides and metal particles deposited on carbon nanotubes.

[0154] The air contacting electrode matrix can also be made of non-carbon based materials. Any material that provides electrical conductivity and is stable in electrolyte solution can be used. Examples may include, but are not limited to, silicon or sulfur compounds (such as SiO2, SnS), oxides (such as aluminosilicate, ultramarine blue, Al2O3) or titanium compounds (such as Ti4O7 or Ti5O9 or TiB2). Non-carbon based long chain polymers may also be used. [0155] The air contacting electrode may be made of various mixtures or combinations of carbon-based materials with non-carbon-based materials. The air contacting electrode may be made of various mixtures or combinations of carbon-based materials and other materials described herein.

[0156] Catalyst materials added to the air contacting electrode need not act solely or simply as catalysts for oxygen reduction or water oxidation. These materials can actually take part and play a role (either partly or completely) in the proper cell discharge or cell charging reaction. By themselves participating in either a reduction or oxidation reaction, these materials can effectively provide either higher load voltages for a working cell or increased capacities in ampere-hours than would otherwise be seen in these cells. These materials may also play a role in lowering the required charging potentials. This increase in cell operating voltage, increase in cell capacity, or lower required cell charging voltages can lead to greater cell capacities, better cell cycle efficiency, greater power capacities, and improved life cycle.

[0157] As an example, MnO2 as an additive to an air contacting electrode can actually participate in the cell discharge reaction through the so-called dual injection process. This entails the introduction or intercalation of protons from the aqueous electrolyte solution and the reduction of Mn oxide by electrons from the external circuit. This dual injection process can be expressed as:

MnO2 + H + + e^- MnOOH

If the air-contacting electrode is still discharging, the MnOOH produced can be further reduced in the second stage:

MnOOH + 3H + + e^- Mn²+ + 2H2O [0158] By participating in the actual reaction, the cell capacity in ampere-hours can be increased. The advantage of Mn oxides is that they can undergo both oxidation and reduction. As a result of the oxidation of already reduced manganese oxide, the reduced manganese oxide may be regenerated and restored to its previous oxidation state and may be able to undergo further reduction reactions. Oxygen derived from either outside air or dissolved oxygen in the electrolyte (or present in the cell) can help partially reoxidize these materials during periods of lower discharge rate or during periods of non-discharge. Being reoxidized, these manganese oxides may be further available to continue the reduction, thereby providing additional cell capacity in ampere-hours. In this sense, this may allow a significant proportion of the total oxygen discharge capacity of the cell to increase.

[0159] Possible examples of such air contacting electrode additions that could participate in actual reduction / oxidation reactions may include, but are not limited to, transition metal oxides such as Fe2O3, CoO2, Co3O4, MnO2, MnOOH, Mn5O8 or CeFe2O4 . Transition metal oxides can also provide beneficial effects either by catalyzing the cell charge or cell discharge reaction, or in fact by changing the cell charge / discharge reactions by a new oxidation / reduction pair or electrochemical shift reaction, resulting in higher operating cell voltages. Examples of other suitable oxides may include the general class of Mn oxides described by the general formula MnxOy (e.g. Mn2O3, Mn3O4 or Mn5O8 and higher oxides) where subscripts x, y, z and w are any suitable set of numbers, such as (1-z / 2) <y / x <(2z / 2) and <2. Further examples of other suitable oxy-hydroxides may include the general class of Mn oxides described by the general formula MnxOy (OH) of (H2O) in (e.g. Mn2O3, Mn3O4 or Mn5O8 and higher oxides) where subscripts x and y are any suitable set of numbers, such as 1 <y / x <(2-z). Manganese can have many different degrees of oxidation. Because of the stability of these oxidation states, such as 2+, 3+ and / or 4+, any single manganese oxide composition may actually contain a stable mixture of different types of oxides, such as e.g. MnO2, Mn2O3, Mn3O4 and MnO.

[0160] It is well known that manganese oxide particles can be produced in various crystal structures. It is expected that the specific manganese oxide crystal structure will affect the catalytic and electrochemical properties as well as the cell efficiency. When manganese oxides are used alone or in combination with physical mixtures of other suitable additives (e.g. carbon, inclusion of other metals, such as W or Mo, or by adding selected oxides, sulphides or borides, such as PtO2, NiO2, V2O3, V2O5, Nb2O5, MoO3, ZnO2, SnO2, Fe2O3, W2O3, Co3O4, CoO, Al2O3, Bi2O3, Yb2O3, Ge2O3, CeO2, B2O3, ZnO, TiO2, ZrO2, TiS2 or TiB2) the connection can show improved cell efficiency and additional stability, especially in the chloride-based electrolyte. Other suitable compounds that can be used alone or added to manganese oxides may include transition metal oxides, which also contain metal. Examples may include substances such as Mn1,5Ni0,5O4 or PbMnOx, where the subscript x may be any suitable number, such as 2 <x <8 (e.g. 2, 3, 4, 5,6,7, or 8). Other examples of possible stand-alone material for air contacting electrodes or as additions to an air contacting electrode may include transition metal oxides, which also contain lanthanide groups, alone or in combination with other materials (e.g. LaMnO3 or LaMnO3 + a), where the subscript a may have appropriate values, such as a = 1 or 0 <a <1 (e.g. 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0).

[0161] Another group of materials may include compounds having a lanthanide atom, a metal, and a transition metal oxide. These compounds may have a general formula

LaMxMnyOz, where La is the appropriate element of lanthanide, M is the appropriate metal and Mn is manganese. Subscripts x, y and z may be appropriate numbers chosen so that the compound is electrically stable, such as 0 <x <1, x + y = 1, 3 <z <4. Examples of this class of compounds may include, but are not limited to such relationships as

LaNi0,5Mn0,5O3, LaCu0,5Mn0,5O3 or La0,8Sr0,2MnO3 or La2 / 3Ca1 / 3MnO3, La1 / 2Sr1 / 2MnO3. [0162] Other examples of suitable oxygen electrode additions include compounds of the general formula MnxMyOz, where Mn is manganese, M is a suitable metal (e.g. selected from the group of bismuth, indium, yttrium, yttrium or niobium), O is oxygen, and subscripts x, y and z are relevant numbers such as 0 <x <1, x + y = 1, 1 <z <4.

[0163] Another example of suitable oxygen electrode additions includes compounds of the general formula MnxMyAzOaHb, where Mn means manganese on its +4, +3 or +2 or on a fractional oxidation state between +4 and +2, M is a suitable metal or transition metal, which can be on 4+, 3+ 2+ oxidation state, like lead tin, germanium, titanium, zirconium, boron, aluminum, indium, bismuth, copper, zinc, nickel, cobalt, iron, molybdenum, yttrium, scandium, niobium, ytterbium, A is a suitable alkali or alkaline earth metal, and H is a suitable halogen. Subscripts x, y with, a and b are that the compound is electrically neutral, as for metal M with oxidation state 4+ and Mn with oxidation state 4+, 4x + 4y + z + b = 2a, just like for metal M on oxidation state 3+ and Mn on oxidation state 4+, 4x + 3y + z + b = 2a, as for metal M with oxidation state 2+ and Mn with oxidation state 4+, 4x + 2y + z + b = 2a, as for metal M with oxidation state 3+ and Mn with oxidation state 3.5+, 3.5x + 3y + z + b = 2a, as for metal M with oxidation state 4+ and Mn with oxidation state 3+, 3x + 4y + z + b = 2a, just like for metal M on oxidation state 3+ and Mn on oxidation state 3+, 3x + 3y + z + b = 2a, as for metal M on the oxidation state 2+ and Mn on the oxidation state 3+, 3x + 2y + z + b = 2a, as for metal M with oxidation state 4+ and Mn with oxidation state 2+, 2x + 4y + z + b = 2a, as for metal M on the oxidation state 3+ and Mn on the oxidation state 2+, 2x + 3y + z + b = 2a, as for metal M on the oxidation state 2+ and Mn on the oxidation state 2+, 2x + 2y + z + b = 2a, for example, such compounds may be Mno, 97Bio, o3O2H, Multiplication, 97Bio, o3Nao, o3O2Ho, 97.

[0164] Another possible type may be a suitable transition metal, a suitable alkali or alkaline earth metal and including a phosphate group. This general class of compounds may have the general formula AxMyPO4 in which A is an alkali or alkaline earth metal and M is a suitable transition metal. The subscripts x and y are such that the compound is electrically stable, such as x + 2y = 3. Examples of this class of compounds may include LiMnPO4, LiCoPO4 and LiFePO4.

[0165] Any of the additives or catalysts described or mentioned above (alone, in combination or together with other suitable materials mentioned above) can act by catalyzing oxygen reduction reactions or water oxidation to produce oxygen. In addition, all the possible cathode additives listed above can also work to provide a new mechanism or path for the discharge or charge reaction where these materials themselves undergo a reduction or oxidation reaction, thus directly contributing to the number of coulombs carried during the cell reaction. These materials can also act as an electrochemical conveyor. For example, the material itself may be reduced during cell discharge, and then may be reoxidized (and available for further reduction reactions) by side reactions with oxygen or any other suitable oxidizing agent present in the cell. Oxygen or other oxidizing agent may be available from outside air or present in dissolved form (such as dissolved oxygen) within the liquid electrolyte. Oxygen-assisted "recharging" reaction can help increase cell charge voltage, increase cell capacity, or reduce cell charge voltage.

[0166] By undergoing valency changes during cell oxidation / reduction, these additives / catalysts can be reduced or oxidized. This reduction and oxidation reaction can lead to cells having two voltage flattens when the cell is charged / discharged. One voltage flattening could be due to the usual zinc-air cell reactions that occur during charging / discharging. Other voltage flattening could be caused by oxidation / reduction of the additive itself or a coupled shift of reaction in which the additive or parts of the additive are involved.

[0167] Any of the above-mentioned additives or catalysts may be involved in more than just one of the reaction mechanisms above. A given catalyst can act either as a direct catalyst for water oxidation or oxygen reduction, acting simultaneously or at a later time as an electrochemical reduction and oxidation conveyor to effectively increase the cell's potential under load, increase the cell's capacity in am24 per hour and / or reduce the cell's charging potential. . A particular pair of reduction and oxidation does not have to include only the selected material and oxygen. Other reducing agents (present in the cell itself or introduced from the outside) can be used effectively. [0168] Each of the various catalysts or additives described above (for example manganese oxide) could itself undergo oxidation / reduction reactions by itself by forming a reaction intermediate with any suitable cell component normally present in the cell or electrolyte, or produced in the cell or electrolyte during charging or discharging. The additive may also optionally undergo oxidation and / or reduction reactions by forming an intermediate reaction product with any product produced in the cell during cell charging or during cell discharge. [0169] As an example, the oxygen gas present in the cell can reoxidize the reduced compound. This newly oxidized compound can then be readily available to undergo further reduction reactions in the cell. This may increase the cell's capacity in ampere-hours. This reoxidation of one of the reduced components of the cell by oxygen may occur when the cell is at rest, i.e. it is not discharged, or can occur even during low-speed discharges, where oxygen reoxidation is able to compete with cell discharging rates and re-oxidize the material after it has been reduced in the cell's reaction. [0170] The oxidizing agent that helps in the regeneration of the cathode material need not be oxygen. It can be any suitable oxidizing agent present in the cell, electrolyte or introduced from outside the cell.

[0171] Examples of oxidizing agents may include KMnO4, N2O, other suitable manganese compounds, or any other suitable compound known to change the number of oxidation in solution. In particular, vanadium and iron compounds are known to occur at varying degrees of oxidation, and their well-known reduction and oxidation vapors can behave as a reduction and oxidation conveyor in this system to help re-oxidize selected air contacting electrode additives. [0172] During cell discharge at constant current, two discharge voltage regimes may occur. One lower voltage level may be due to the usual discharge reactions (e.g., oxygen reduction) normally found in an air zinc cell. Another, higher voltage level during cell discharge may be due to the fact that the catalyst and / or the additive undergo separate oxidation / reduction vapors. This can affect the extension of the cell discharge reaction, thereby increasing the cell's capacity in ampere-hours. In some cases, any number of multiple-discharge voltage regimes may occur.

[0173] It is also possible for the scenario to occur where voltage flattening at higher levels during cell discharge may result from the normal combination of two half-cell reactions: metal oxidation and oxygen reduction, while the second lower voltage flattening may result from metal oxidation and the reduction reaction of the additive itself. It can also have a general effect on prolonging the cell discharge reaction, thereby increasing the cell capacity in ampere-hours.

[0174] Similarly, when charging a cell at constant current, two charging voltage regimes may occur. One higher level of potential during electrical charging in a zinc cell may occur due to the usual reactions occurring on the air-contacting electrode when charging the zinc-air cell (i.e. water is oxidized to produce gas as oxygen). A second, lower charge voltage level may occur due to the catalyst or additive subjected to a separate oxidation reaction. In some cases, any number of rechargeable voltage regimes may occur.

[0175] It is also possible for the scenario to occur where a lower charge voltage flattening occurs due to the normal pair of reduction and oxidation of zinc and air, while a higher voltage flattening occurs due to the oxidation of a particular additive to the air contacting electrode.

[0176] The range and capacity of the cell in ampere-hours due to these new higher discharge voltage flattenings or reduced required charge in ampere-hours may depend on the amount of additive present. Since the additive itself can participate in the discharge and / or charge reaction, the duration of this additional voltage flattening will therefore depend on the amount of additive present.

[0177] The improvement in cell range and capacity in ampere-hours can also be largely independent of the amount of additive and rely heavily on one or more shift reactions where compounds of interest that are oxidized or reduced are constantly regenerated in the cell.

[0178] When discharging the cell, oxygen from the surrounding air may enter the cell through the porous air-contacting electrode and oxygen may be reduced at specially designed catalytic sites in or on the air-contacting electrode. The air contacting electrode may be a carbon-based electrode or may be based on other suitable materials. Meanwhile, on a metal electrode (which may be zinc), the zinc passes into the solution in the form of soluble zinc ions. In the presence of a chloride-based electrolyte, zinc chloride may be poorly soluble in the aqueous electrolyte. As the cell continues discharging and the formation of more zinc ions in the solution, the zinc chloride solubility limit may be exceeded. This can cause some zinc chloride to precipitate. Methods of dealing with precipitation according to an embodiment of the invention will be described in more detail below. When the cell is charged, the reverse electrochemical reaction occurs. Oxygen gas is produced by the oxidation of a liquid electrolyte on an air-contacting electrode, while the zinc metal can be regenerated (applied by plating) back onto the zinc electrode.

[0179] Simplified discharge / charging processes in the chloride electrolyte, which can have a pH of about 6, can be described by the following reactions:

When Discharging a Cell [0180]

Cathodic reaction: 2H + + I / 2O2 + 2e^- H2O

Anode reaction: Zn Zn²+ + 2e^-.

When Charging the Cell [0181]

Cathodic reaction: H2O + 2Cl^- 2HCl + I / 2O2 + 2e^-

Anode reaction: ZnCl2 + 2H⁺ + 2e Zn + 2HCl [0182] Zinc compounds generated during cell discharge in an ammonium chloride electrolyte can be more accurately described as Zn (NH3) 2Cl2.

[0183] On an air-contacting electrode, oxygen gas obtained from the surrounding air may enter the cell through an air-permeable hydrophobic membrane. When the cell is being charged, oxygen gas can be produced by water electrolysis (oxidation) on a porous electrode in contact with air. [0184] One of the side effects of the use of aqueous chloride-based electrolytes in rechargeable zinc-air battery technologies is that during charging the cell (at anode potentials), an undesirable side reaction may occur:

(1) 2Cl^- Cl2 (g) + 2e^- E0 = 1.36 V [0185] Chlorine production may be an undesirable reaction in this electrolyte system as it may reduce the overall charge efficiency of the cell. This is because electricity can be used to produce chlorine (an adverse reaction) and not to release oxygen (a desired reaction). Therefore, it may be desirable for the battery system to be designed so that when the cell is charged, the anode potentials promote oxygen release and minimize chlorine release.

(2) 2H2O 4H + + Oi (g) + 4e^- Eo = 1.23 V [0186] Oxygen release (reaction 2) is expected to mainly occur due to its lower oxidation potential (1.23 volts) because it is thermodynamically more favorable than chlorine release (reaction 1) with higher potential oxidation of 1.36 volts. However, every reaction has overpotential. The term overpotential refers to the amount of voltage (above the theoretical potential) necessary to cause a given reaction to actually occur. It turns out that the release of chlorine is a much simpler chemical reaction and has a lower overpotential than the oxidation of water to O2 (g). This means that in aqueous chloride environments, unwanted chlorine release may be more likely than oxygen release.

[0187] The chlorine produced during cell charging can dissolve in water to form hypochlorous acid, HClO. Hypochlorite ions can then decompose into chloride, several known oxidized chlorine compounds or even free dissolved gas in the form of chlorine depending on the conditions. Even if the chlorine gas as such does not remain intact, this reaction may still be undesirable in the cell because it reduces the overall charging efficiency.

[0188] There are a number of practical ways to minimize or reduce unwanted release (or improvement of oxygen production efficiency) of chlorine (or hypochlorite). Since the release of oxygen is beneficial under low current density conditions, one possibility may be to reduce the charge current density to promote the release of oxygen (instead of chlorine). In some embodiments, desirable charging current densities can be from about 10 mA / cm² up to about 200 mA / cm² and may vary depending on the application up to the maximum charging or discharging current that the battery will tolerate.

[0189] Another approach may be to adjust the pH of the electrolyte. At certain pH values, oxygen production may be more advantageous than chlorine evolution. Higher pH promotes O2 release relative to Cl2 release. The electrolyte pH can be slightly increased and buffered by the addition of ammonium hydroxide or ammonium citrate. Chlorine release promotes pH below 2. While ammonium chloride acts as a pH buffer in this system, the addition of aqueous ammonium hydroxide would increase the electrolyte pH without adversely affecting electrolyte conductivity or other performance properties.

[0190] Another approach may be to use air contacting electrodes or selected catalysts in an air contacting electrode that have high chlorine release overpotentials and / or very low oxygen release overpotentials. In this way, oxygen release is better when charging the cell. This can be achieved by modifying the electrode surface (as will be discussed in more detail below) or by adding materials such as MnO2, which are well known to have low oxygen release overpotentials. Similarly, the addition of various electrolyte salts has been shown to minimize chlorine release. Examples of such salts or chemicals may include cobalt chloride, iridium oxide (IrO2) or soluble manganese salts. In addition, there are water-soluble additives, such as urea, which are known to react with chlorine, if it is produced, to produce non-toxic, easy-to-drain gases.

[0191] However, it should be understood that an alkaline electrolyte can be used as part of the system disclosed herein if carbon dioxide is first removed from the air. If this happens, all the benefits of the link, as described here, can still be realized.

IV. Zinc-air cell with a third electrode [0192] An aspect of the invention relates to a rechargeable or reversible battery, such as a zinc-air cell, having a zinc electrode and a carbon-based cathode for electrochemical reduction of oxygen gas. This type of cathode may also be known as an air cathode because oxygen, which is chemically reduced, is usually obtained from the surrounding air.

[0193] In traditional limited metal-air charged electric cells, it is expected that the air-contacting electrodes will perform two separate, even opposing functions (hence the occasional name of the dual-function air-contacting electrode). The first function of the dual-function electrode is to allow oxygen reduction to occur during cell discharge. The second function of the bifunctional electrode is to allow the release of gas as oxygen while charging the cell.

[0194] Because the bifunctional air-contacting electrode serves many different purposes (e.g. reduction and oxidation), there are several challenges for these air contacting electrodes. First, there are only a few conductive materials that will not easily corrode in aqueous electrolytes at these wide shifts in the applied electrical potential. This corrosion is particularly common when using aqueous chloride electrolytes. This makes the selection of the current collector of the electrode in contact with air much more difficult. Secondly, the formation of oxygen bubbles during cell charging can introduce mechanical and pressure stresses in the porous carbon structure, which tend to weaken this porous electrode in contact with air.

[0195] One possible approach is not to require that the same porous air-contacting electrode serves to carry out both the oxygen reduction and oxygen production reactions. Instead, in some embodiments, a third or auxiliary electrode may be provided to the cell instead of the standard air contacting electrode. This auxiliary electrode can have only one function: for example, only cell charging and associated oxygen production or only cell discharge and oxygen reduction. Thus, one air contact electrode can only be provided to reduce oxygen during cell discharge, while the other air contact auxiliary electrode can be designed and used only to oxidize water and produce oxygen during cell charge. An auxiliary electrode designed to produce oxygen can be placed between the commonly used air contact electrode and the metal electrode or placed on both sides of the metal electrode. Since the ancillary electrode would normally only be used during cell recharging and oxygen production, it could then be optimized for recharging (oxygen production) using optimized oxygen generating catalysts, while a conventional air contact electrode would be optimized for discharging (oxygen reduction).

[0196] FIG. 12 shows an example of this new electrode configuration. FIG. 12 provides a construction diagram with three electrodes in an electrically rechargeable zinc-air cell. Here, a conventional porous electrode (AA) contacting the air and a solid zinc electrode (CC) are separated by a liquid electrolyte. A third auxiliary electrode (BB), which is only used when charging the cell, and electrically isolated from the AA electrode, can be placed between the CC electrode and the AA electrode. In some embodiments, the secondary BB electrode may be electrically isolated from the AA electrode through an insulator or through a gap / gap.

[0197] The AA electrode may be a standard porous carbon air contact electrode or any other type of air contact electrode that has been designed and optimized for oxygen reduction. The CC electrode may be a zinc metal electrode or any other metal electrode or anode as described elsewhere herein. In some cases, the third electrode, the auxiliary electrode (BB), will only be used when charging the cell. Suitable materials used to make this auxiliary electrode may include, but are not limited to, metal, metal oxide or carbon produced in the form of a screen, foil, mesh or foam, wire, expanded metal mesh, or it may be pressed or sintered metal, carbon or a suitable metal oxide. [0198] When discharging the cell, the AA and CC electrodes are connected and electric currents are generated.

[0199] When charging the cell, BB and CC electrodes can be automatically connected to the circuit using an electric switch. Electrical currents from the external circuit can be applied across these electrodes to produce oxygen gas from the aqueous solution.

[0200] By using an additional electrode system, another (probably cheaper and more efficient) electrode dedicated to the charging part of the cell can be obtained. When discharging the cell, CC and AA electrodes, connected through an external circuit, can provide electricity. The current flow can be in the same direction as in traditional cells. Oxygen from the surrounding air can be electrochemically reduced by the electrons produced on the zinc electrode.

[0201] Before charging the cell, the AA electrode may be disconnected from the circuit connecting it to the CC metal electrode (e.g. electrode) and the auxiliary, third electrode (BB) can be automatically electrically switched to the cell's electrical circuitry and connected to the metal electrode CC. Now, during charging, BB and AA electrodes are electrically connected and used. The BB auxiliary electrode may in particular be configured in a form with increased surface areas. These current collectors may be in the form of a grid, porous plates, wires, screens, foam, compacted or sintered powder, nanoparticles, strips or other suitable open structures or with a large surface area. Here, the surface area can be much larger than its geometric trace. This may allow better contact with the electrolyte so that oxygen production can be easier. The porous physical properties of this electrode are designed to allow the electrolyte to flow through it, and so that the oxygen gas produced can easily escape. Since O2 gas is produced only on this porous auxiliary electrode, the AA oxygen reduction electrode will not be damaged.

[0202] This secondary, third electrode may also be designed to contain specific catalysts to increase O2 release (catalysts having low over oxygen production potentials). In addition, this third electrode can then be protected against reverse currents when the cell is discharged using switching diodes, which allow the electrode to be used only when charging the cell.

[0203] Once the cell has been fully charged, the third (charging) BB electrode can be electrically disconnected from the cell's electrical circuit assembly, and the standard CC metal electrode and conventional air-contact AA electrode can be reconnected. [0204] When discharging the cell, the AA electrode in contact with the air and the CC metal electrode can be electrically connected.

[0205] When charging the cell, the BB electrode in contact with the air and the CC metal electrode can be electrically connected.

[0206] Any electrical switching or connection / disconnection mechanism known in the art can be used to provide the desired connections during charging and discharging. Such connections can be made in response to instructions provided by the control device.

[0207] The electrode contacting the air for recharging may be:

1. Larger than the air-contact discharge electrode to allow fast recharging at lower current densities.

2. Smaller than the air contacting discharge electrode to occupy a smaller volume and not block the air contacting electrode.

V. Metal hydrides as the battery anode [0208] In some embodiments of the invention, titanium hydride, TiH2, may be the appropriate metal electrode / anode material in the currently described horizontally configured battery.

[0209] Unlike other AB5 metal alloys for hydrogen storage, such as LaNi5, Ti powder and its hydride may be cheaper and may have higher energy densities. Also, unlike other metal electrodes that dissolve when subjected to oxidation, TiH2 does not dissolve as a result of its oxidation. TiH2 just becomes solid metallic Ti.

[0210] As an anode, during the cell discharge cycle, TiH2 can release two protons and two electrons to form metallic Ti. During charging, two protons and two electrons can be recycled to metallic Ti, and TiH2 can be produced again. Discharge / charging reactions can be:

Discharge: TiH2 Ti + 2H + + 2e^-

Charging: Ti + 2H + + 2e^- TiH2 [0211] Typical metal hydrides wear out after numerous discharge / charge cycles due to the induced mechanical stress. This may cause metal powders and metal hydrides to degrade and form smaller sizes. These smaller powders do not adhere well together, which leads to reduced electrical conductivity and poor cell performance. However, in combination with the present proposed construction of a horizontally configured cell as hereinafter referred to as where the metal electrodes are arranged horizontally, the action of gravity can help the deposition of even finely divided Ti and TiH2 powder back towards the current collector below. Even if the metal electrodes are slightly inclined, gravity should nevertheless allow Ti and TiH2 powders to settle back onto the current collector in a relatively uniform or uniform manner. Since TiH2 and Ti powders will be in close contact with each other and with the current collector, the oxidation and reduction of this metal electrode can be continued with good efficiency.

[0212] The Ti powder can also be modified by treatment with any of the various treatment methods proposed herein to give Ti greater electrical conductivity.

[0213] Titanium hydroxide can act as a standard battery or as a titanium hydride / air battery. Features or parts of the discussion for titanium hydride electrodes may also apply to zinc-air batteries or other metal anode batteries, and vice versa.

VI. Horizontal cell configuration / orientation [0214] According to another aspect of the invention, the metal anode battery system, such as the zinc-air battery system, may have a horizontal cell configuration. FIG. 1 shows rechargeable zinc-air cells arranged in a horizontal orientation according to an embodiment of the invention. The battery system may include plastic housings 100a, 100b, air contacting electrode 102a, 102b, metal electrode 104a, electrolyte 106a, 106b, and airflow channel 108a, 108b. In some embodiments, the air contacting electrode 102a, 102b may include a hydrophobic membrane 110, carbon and catalyst 112, a stretched titanium mesh 114, and conductive carbon 116. The air contacting electrode can act as a cathode when the cell is discharged. The metal electrode acts as an anode when the cell is discharged. In other words, when the cell is discharged, the air-contacting electrode acts as a cathode, while the metal electrode acts as an anode. When loading the cell, these roles are reversed. A porous, carbon, air-contacting electrode then acts as an anode (loses electrons), while a metal electrode acts as a cathode (receives and receives electrons). In some embodiments, the metal anode battery cell system may include a metal electrode, an air contacting electrode, and an aqueous electrolyte solution. In some embodiments, the electrolyte may have a pH in the range of about 3 to 10.

[0215] In some examples, the insulating plastic housing can be made of various plastics, including, but not only Noryl, polypropylene (PP), polyphenylene oxide (PPO), polystyrene (PS), high impact polystyrene (HIPS), acrylonitrile-butadiene-styrene (ABS), poly (ethylene terephthalate) (PET), polyester (PES), polyamides (PA), poly (vinyl chloride) (PVC), polyurethanes (PU), polycarbonate (PC), poly (vinylidene chloride) (PVDC), polyethylene (PE), polycarbonate / acrylonitrile butadiene styrene (PC / ABS) or any other polymer or a combination thereof. In some embodiments, the plastic used to make the housing can be selected because of its ability to tolerate high temperatures, i.e. as high as the boiling point of the electrolyte. In some embodiments, the plastic material used to make the housing can be injection molded. The plastic housing made of injection-molded plastic such as, but not limited to, Noryl can be designed to keep both the zinc electrode fixed (shown on the bottom of the cell) and the air contacting electrode. The zinc electrode at the bottom of the cell can be separated from the extending current collector screen of metallic titanium (embedded inside the bottom of the porous carbon electrode in contact with air at a fixed distance. This separation space between the zinc electrode (metal electrode / anode) and the titanium screen of the current collector for the air-contacting electrode / cathode is filled with an electrically conductive aqueous chloride electrolyte solution.

[0216] Housing 100a may surround the cell. The air contacting electrode 102a may be provided as the top layer of the cell. Metal electrode 104a may be provided as an intermediate part of the cell. An air flow duct 108b may be provided between the metal electrode 104a of the first cell and the air-contacting electrode 102b of the second cell. The electrolyte 106a may be provided inside the cell. The electrolyte 106a may be included in the housing 100a as well as in the metal layer of the electrode 104a. In alternative embodiments, the positions of the air contacting electrode and the metal electrode can be switched such that the metal electrode can be provided as an upper layer and the air contacting electrode can be provided as an intermediate part.

[0217] In some embodiments, the air-porous electrode may be a carbon-based oxygen cathode or a polymer-based oxygen cathode having an air-permeable hydrophobic catalytic membrane and / or a corrosion-resistant current collector, where during electrical charging under potentials anode oxygen release may be beneficial. Air contact electrodes may also include any materials known in the art.

[0218] In some embodiments, low temperature gas plasma treatment can be used to significantly increase metal adhesion to various plastics. Gas plasma has been shown to improve the adhesion of vapor-deposited metals to various polymer surfaces. By treating polymer surfaces with various gas plasmas before applying structural adhesives, a stronger, more durable bond can be created. Examples of desired gas plasmas may include O2, CF4 / O2 or N2 mixtures. It is expected that this treatment will improve the adhesion of the plastic housing to the metal electrode. In both single-cell and multi-cell constructions, there can be many places within the cell piles, where the plastic surface is adhesive bonded to the metal surface by means of structural adhesives. Such a permanent seal can translate into longer cell life.

[0219] There are many clear advantages of horizontal electrode orientation. First, the horizontal configuration can allow quick and cheap connection of cells from injection molded containers or plastic housings. Another advantage is that a porous battery separator is not needed. In most batteries, separation membranes are often expensive, and puncturing such a membrane is also a key way to damage these batteries. By eliminating the need for a porous battery separator, horizontally oriented cells can be cheaper and more reliably manufactured and used. In some embodiments, the liquid electrolyte within a particular cell may directly contact the metal electrode of the same cell. In some embodiments, the liquid electrolyte may or may not directly contact the cell's porous air-contacting electrode. No separation layer is needed between the liquid electrolyte and the metal electrode. In some embodiments, no separator or separation layer can be provided between the liquid electrolyte and the metal electrode and / or the air contacting electrode. For example, a rechargeable battery cell with a metal anode that has a metal electrode, an air contacting electrode, and an aqueous electrolyte between the metal electrode and the air contacting electrode can be provided, whereby the air contacting electrode can contact the electrolyte directly and between the electrode that contacts the air and the electrolyte have no separator.

[0220] The elimination of the separation membrane between the metal electrode and the air contact is the key to lowering the battery costs to acceptable levels and helps to extend the battery life cycle so that it becomes suitable for industrial use. By orienting the cells so that the metal electrode is at the bottom, gravity helps prevent clad metal contact (and shorting) with the air contacting electrode above. In some embodiments, the metal electrode may be a zinc metal anode, and gravity may prevent contact of the deposited zinc plating with the above air contacting electrode. This creates an extremely reliable battery, because there is no membrane that could be damaged, and the cell is based on gravity to ensure proper operation. A rechargeable battery system with a metal anode can be used for a large number of discharge / charge cycles without physical material degradation or a significant decrease in the efficiency of the battery cell system. In some embodiments, the system may be suitable for about 100 or more, 200 or more, 300 or more, 350 or more, 400 or more, 450 or more, 500 or more, 700 or more, 1,000 or more, 1,500 or more, 2,000 or more, 3,000 or more, 5,000 or more, 10,000 or more, or 20,000 or more discharge / charge cycles without significant degradation. [0221] During the cell operation, the discharge reaction products may be primarily zinc chloride. When the solubility of zinc chloride exceeds its solubility limits (and because it forms in chloride-based electrolytes, the presence of chloride ions, due to the common ionic effect, will quickly exceed the solubility limits of zinc chlorides) it precipitates. Here, the horizontal configuration of the cell, together with the help of gravity, should help the deposition of the precipitating zinc chloride particles on the horizontally placed zinc metal electrode below. Because zinc chloride particles are deposited on / near the zinc electrode, zinc ions will undergo much less migration. This means that during cell charging, when the zinc settles back onto the metal electrode, there may be a loss of less zinc to other places in the cell. This leads to significantly improved efficiency of the zinc cycle and increased cell capacity. The elimination of membrane separators in rechargeable cells also means that internal losses related to resistance within cells can be minimized or reduced. This leads to higher operational potentials and smaller amounts of waste heat generated.

[0222] The horizontal geometry of the cell may also make it possible to establish a repetitive constant distance between the metal (zinc) electrode (anode) and the current collector of the contacting air. This helps regulate the electrolyte resistance more consistently. In some embodiments, the battery cell may have a housing that holds the metal electrode and the air contacting electrode at a constant distance from each other. A fixed distance can determine the space in which liquid electrolyte can be found. Secondly, in horizontal geometry, where each individual aerated electrode is at the top of the cell assembly, i.e. the air contacting electrode is facing upwards, numerous zinc-air cell assemblies can be stacked on top of each other. This not only increases the energy density (because the cells can then be tightly packed together), but also allows the design of the battery system with open air spaces between the individual cells. This open space can act as a horizontal gas flow manifold, where air can be pumped through the battery housings between individual cells to circulate air / oxygen at the top of each individual air-contacting electrode.

[0223] FIG. 2 shows an example of individual cells that can be stacked on top of each other. The cell may include a plastic housing 200a, 200b, an air contacting electrode 202a, 202b, metal electrode 204a, 204b and electrolyte 206a, 206b. The liquid electrolyte can be contained in a plastic housing and can be additionally supported by a metal electrode at the bottom of the cell. In some embodiments, the air contacting electrode may be provided above the electrolyte. The electrolyte can be pressed and held between the underlying metal electrode and the upstream air contacting electrode. One or more air flow channels 208a, 208b may be provided between individual cells. An air flow duct 208b may be provided between the metal electrode 204a and the air contacting electrode 202b.

[0224] Thus, two individual links can be separated from each other by means of a horizontal passage or air duct (not drawn to scale). This horizontal cell configuration can allow air / oxygen pumping and circulation between the cells to individual air-contacting electrodes. Air / oxygen flowing to the air contacting electrodes can enable the cells to maintain the required oxygen supply even at higher current densities, and the air flow additionally provides the cells with cooling. The air circulation need not be continuous and the air flow velocities can be carefully controlled by feedback mechanisms. In some embodiments, air can flow between individual cells in a stack entirely in the same direction for each of the air flow channels. Alternatively, the air flow between individual links in the stack can be designed to flow in different directions.

[0225] In one example, a fan (which may include axial fans, radial fans, crossflow fans), a pump, or any other suitable mechanism for producing airflow may be used. One or more actuators may be part of the airflow mechanism or may communicate with the airflow mechanism. Examples of cylinders may include, but are not limited to, motors, solenoids, linear cylinders, pneumatic cylinders, hydraulic cylinders, electric cylinders, piezo cylinders or magnets. The actuators can cause airflow based on the signal received from the controller. Actuators may or may not be connected to an energy source. One or more sensors may be provided in the cell assembly. In some embodiments, the sensors may be temperature sensors, voltage sensors, current sensors, or pH sensors. These sensors can communicate with the controller. Based on the signals received from the sensors, the controller can provide signals to air flow mechanisms that can change and / or maintain air flow between the cells. [0226] As previously mentioned, there are a number of advantages of horizontal geometry in metal anode cells.

A. Horizontal geometry may allow constant / regulated electrolyte resistance, which may require less active management of cell temperature, current density or electrolyte levels.

B. Horizontal geometry can also provide ease of physical stacking and stacking of many links.

C. There may not be a need for a battery separator, because gravity helps separate and deposit materials of different densities on a metal electrode.

D. The precipitated discharge product can be assisted by gravity, as previously mentioned, to settle as an even (or substantially even) layer on the underlying metal electrode.

E. The horizontal design may help cool the cells and may also allow more oxygen to be supplied to individual air contacting electrodes, which may allow higher currents.

F. Gravity can also help with electrolyte flow, as described later.

G. Packaging can hold the links in place.

[0227] The horizontal design of the battery need not be limited to a metal anode battery, such as a zinc-air battery. The design with horizontal cells can also be used in other battery systems, where a solid or poorly soluble discharge product is formed during cell operation or during idling. This may include, but is not limited to, lead-acid ("flooded" and VRLA) batteries, NiCad batteries, nickel metal hydride batteries, lithium ion batteries, polymer lithium ion batteries or molten salt batteries.

VII. Centroid design for inter-link connections [0228] According to an aspect of the invention, systems and methods for low-cost, scalable inter-link connections can be provided.

[0229] Connecting multiple individual cells together in series electrical connection while maintaining a horizontal geometric configuration for one or more cells (or each cell) can easily be achieved by what may be referred to as "centroid". "Centroid" can be made by taking an electrode in contact with air from one cell and folding it along both sides with a separate metal element. This metal element can be electrically connected to the cell above it or it can itself be a metal electrode for the cell above it. The space between the metal electrode (now placed on top) and the air contacting electrode (now placed below) can be separated by a thin air channel 208a, 208b that allows air to flow on top of these air contacting electrodes. This is shown in FIG. 2. The centroid subassembly obtained resembles a hat section when viewed through air path 108a, 108b (from front to back) as shown in FIG. 1. The metal electrode and the air contacting electrode can be substantially vertically aligned and horizontally oriented. [0230] FIG. 1 illustrates how the metal electrode 104a of the first cell can be clamped around the air-contacting electrode 102b of the second cell, thereby connecting the first and second cells in series. The metal electrode of the first cell and the air-contacting electrode of the second cell can be electrically connected in any number of suitable ways. For example, a metal electrode or an air contacting electrode can be clamped together, soldered together, welded together, pressed together, joined together with a conductive adhesive, soldered to each other or otherwise attached.

[0231] In some embodiments, the air contacting electrode and the metal electrode may be separated by a fixed distance, wherein the air contacting electrode may be located above the metal electrode. The constant distance may be equal across the surface of the air-contacting electrode and the metal electrode. Alternatively, the set distance may vary across the surface area of ​​the air contacting electrode and the metal electrode. In some embodiments, the fixed distance may be in a range that may include about 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 1 cm, 1.5 cm , 2 cm, 3 cm or more. The constant distance between the air contacting electrode and the metal electrode may determine the space in which the electrolyte may be contained or delivered. The air contacting electrode and the metal electrode may be part of the same cell. [0232] Any number of cells can be assembled, stacked and connected to obtain any required total operating voltage. Each plastic housing can be a common part designed to match the shape and sealing requirements of each centroid. Each centroid can have unique upper and lower elements formed in plastic. The elements formed in the plastic can be the same from cell to cell, or they can differ. The formed elements can be helpful in stacking cells and in keeping the centroid within the cells. In an automated process, cells are assembled in a modular manner, essentially by layering multiple centroid between two suitable plastic housings. This process can be repeated continuously.

[0233] FIG. 3 is a isometric view of a single cell in accordance with an embodiment of the invention. The cell may have a housing 300, a metal electrode 302, and an air contacting electrode 304. The link may have the desired shape or dimension. For example, the cell may have a rectangular shape, a square shape, a round shape, a triangular shape, a trapezoidal shape, a pentagonal shape, a hexagonal shape, or an octagonal shape. The housing can be shaped to fit around the cell.

[0234] In some embodiments, the housing 300 may have a vertical portion 312. The housing may also have a horizontal shelf 306 that may protrude into the cell. The shelf may protrude from the vertical part anywhere along the vertical part. In some embodiments, the shelf may protrude on or near the bottom of the vertical part, on or near the top of the vertical part, or on or near the center of the vertical part. A vertical portion and / or horizontal shelf may be provided along the entire circumference of the cell or may be provided along one, two, three, four or more sides of the cell. In some embodiments, one or more cell parts may or may not include housing parts (e.g. vertical and / or part of the housing shelf). In some embodiments, the shelf cross-section may be provided as a rectangle, trapezoid, square, any other quadrangle, triangle or may have any other shape. In some embodiments, the top surface of the shelf may be sloped. In some embodiments, the top surface of the shelf may be inclined down toward the center of the cell or may be inclined down to the perimeter of the cell. Alternatively, the upper surface may be flat with horizontal orientation.

[0235] In some embodiments, a metal electrode 302 may be provided below the shelf 306. In some embodiments, the metal electrode may have a horizontal orientation. The metal electrode may be touching the bottom of the shelf. In some embodiments, the metal electrode may be shaped to contact one or more vertical sides 312 of the housing. Alternatively, the metal electrode may be shaped to be in close proximity to the vertical side without contacting the vertical side. The metal electrode may be parallel or substantially parallel to the vertical side in this part.

[0236] In some embodiments, the housing may have a bottom member 314 provided on the bottom of the cell. In some embodiments, the bottom member may be a recess, groove, channel, slot or hole that can be provided in or near the bottom of the housing. The metal electrode can be shaped to fit inside the bottom element. The portion of the metal electrode that fits inside the bottom member may be parallel or substantially parallel to the surface of the metal electrode including the cell. The portion of the metal electrode that fits inside the bottom member may be perpendicular or substantially perpendicular to the portion of the metal electrode that is in contact or in close proximity to the vertical side.

[0237] In some embodiments, the air contacting electrode 304 may include a cell. The air contacting electrode may have a substantially flat configuration. In some embodiments, the air contacting electrode may contact the bottom element 314 of the cell. In some embodiments, the air contacting electrode may be fitted within the lower cell element. In some embodiments, a portion of the metal electrode 302 may be electrically connected by an electrode contacting the air inside the cell's lower element. For example, a portion of the metal electrode may be clamped around the air-contacting electrode inside the cell's lower element. In preferred embodiments, a gap may be provided between the part of the electrode in contact with air enclosing the cell and the part of the metal electrode including the cell. There may be air inside the gap. In some embodiments, air can flow inside this gap.

[0238] In some embodiments, a top element may be provided on the top of the cell. In some embodiments, the top element may be a recess, groove, channel, gap or hole, which may be on or near the top of the housing. In some embodiments, the top element may be a mirror image of the bottom element. In some embodiments, the top element may contain a metal electrode and / or an electrode contacting air above the cell. In some embodiments, the electrical contact between the metal electrode and the air contacting electrode may be pressed between the bottom element of the first cell and the top element of the second cell. In other embodiments, the top element need not be provided. Also, the plastic cell can be injection molded around centroids or other electrical connections.

[0239] Other configurations may be provided for housing components, metal electrodes, and air contacting electrodes. For example, a metal electrode may be provided on top of the shelf. An electrode contacting the air may be provided on top of the cell. Positions of metal and air contacting electrodes can be swapped.

[0240] In some embodiments, the housing may include additional molded elements, such as edge 308. The housing may also include an inclined portion 310. In some embodiments, the edge can capture electrolyte. In some embodiments, some portion of the electrolyte may be directed through the inclined portion 310 in the cell. The electrolyte may be contained in the vertical portion 312 of the cell and may be held by a portion of the metal electrode 302 including the cell. In some embodiments, the edge may allow part of the electrolyte to flow through the edge of the housing and drain below the edge of the housing. This can prevent or reduce electrolyte spillage from the cell. In some embodiments, the electrolyte can be delivered from inside the cell or it can be supplied from a source above the cell or it can be captured, held or fed into a paddle or expansion chamber, pushing up or diagonally up above the cell, so that gravity will push the electrolyte back down when there is space in the cell.

[0241] An additional advantage of the horizontal configuration is that the cell can be designed so that the management of liquid electrolyte becomes much easier. A gravity-based electrolyte management system may be provided in accordance with an embodiment of the invention. As the zinc-air battery gets discharged, the net volume of the liquid zinc electrolyte system may increase. If space is not provided for this increased volume, when the liquid electrolyte increases in volume, the pressure in the cell may increase and the liquid electrolyte may penetrate to the bottom side of the porous electrode in contact with air. This can not only cause flooding of the porous electrode contacting the air, but the pressure difference resulting from the increase in volume of the liquid electrolyte pushing against the porous electrode contacting the air can damage the delicate electrode contacting the air. In small, sealed batteries, additional space must be provided due to such an increase in the volume of liquid electrolyte. However, this extra volume can lower the overall energy density of the cell and can cause problems in a system where many cells are connected in series and all cells must maintain the correct electrolyte level. It also prevents the delivery of new liquid electrolyte to the system or the testing of liquid electrolyte.

[0242] According to an aspect of the invention, this problem can be solved by four horizontally aligned adjacent links, where all four links have a common corner. This horizontal set of four horizontal links can be referred to as "four". Where all four cells meet, these cells can share a fill or overflow or recirculation connection. Each link can be designed to have access to this small connection. Each connection can have a small overflow edge L, which can be tilted slightly above the bottom surface of each air-contacting electrode.

[0243] Figure 5 shows an example of a four-cell four, and FIG. 4A shows a cross-sectional stack of cells inside a gravity-based liquid electrolyte management system. The gravity-based liquid electrolyte management system may include a channel A for removing gas from the tank or container B, which may be in fluid communication with another tank or container C. In some embodiments, inlet or outlet D, E valves or ports D, E may be provided. In some embodiments, the additional tanks or containers F may be in combination with the main tank or container C. Any arrangement of tanks or containers can be provided. They may or may not contain filters that can capture unwanted particles. In some embodiments, the reservoir tanks may also provide the ability to add or remove any desired materials, such as electrolyte additives. As the electrolyte circulates inside the electrolyte management system, its concentration and / or composition are monitored and can be modified as needed.

[0244] The feed fluid transition channel G may supply electrolyte to the entire battery system. The return fluid passage V may return liquid electrolyte to the battery system. The fluid transition passage may include a thick-walled pipe, a thin-walled pipe, a channel, a wick, or any other assembly that can transport fluid. The electrolyte can be supplied to the upper electrolyte tank H. One or more J drain or filling connections may be provided. When the electrolyte K overflows through the tank, it can drip down into the underlying cell and be captured by the overflow bank L.

[0245] The overflow edge L can provide a constant level of liquid electrolyte, which is always in contact with all points of the bottom surface of the air contacting electrode T. P electrolyte can be supplied inside the cell. When discharging the cell, when the liquid electrolyte increases in volume, this edge may allow the excess electrolyte to drain in the horizontal "four". All this can be achieved without the required hydrostatic pressure on the electrode contacting the air. In other words, these unique connections can allow for increasing the volume of liquid electrolyte and gaseous waste while maintaining proper (and automatically regulated) electrolyte levels for each group of horizontally arranged cells. This automatic balancing of electrolyte levels can also help maintain uniform electrical performance. These connections, located in the center of each adjacent four-cell "four", can be vertically aligned directly above the other connections below (in the "four" below) to form a series of vertically oriented supply pipes. These pipes can distribute any overflowing liquid electrolyte from all the cells stacked into a small sewage tray U, located at the bottom of a given cell stack. These connections can include a prismatic M part that helps break down overflowing liquid electrolyte into tiny N drops.

[0246] The cells may comprise an air contacting T electrode and a metal R electrode, which may be connected at one or more connecting points S. An air duct 0 may be provided between the air contacting electrode and the metal electrode. In some embodiments, the air contacting electrode and the metal electrode may form a centroid. The Q housing can be provided for a cell, four or groups of cells or quadruple. The enclosures can be stacked in the battery system.

[0247] One or more valves or connections I may be provided inside the upper electrolyte tank II or drain tray U. This connection may allow the outflow of electrolyte additives and / or some electrolyte. The connection may allow gas evacuation. In some embodiments, the terminals may provide access to conductivity or pH measurements. Connections may have additional other applications.

[0248] During cell charging, when the electrolyte volumes in each cell decrease, the same fill ports can be used to add liquid electrolyte back to each cell in the "four". When charging the cell, you can start the sewage pump to fill the upper "four". The electrolyte overflowing through the highest four-cell horizontally configured four enters the drain pipe and feeds by gravity, simply filling the horizontal "four" below. This transfer can continue and lead to the filling of the next "four" below. The automatic filling of horizontal fours with liquid electrolyte can be carried out quickly, until all "four" in the vertical stack are filled (or filled) with liquid electrolyte. These filling / overflow connections can be designed to also serve a different function. A prismatic relief (M) located under each overflow edge (4-L) can help break down any liquid electrolyte into small drops (N) before they reach the specified four. This can advantageously help to break or disconnect any electrically conductive circuit that would otherwise be formed by a continuous flow of conductive liquid (i.e. a large number of connected individual drops) between individual cells. The uninterrupted flow of the conductive electrolyte could cause a large electrical short circuit in the high voltage circuit formed by the numerous cells arranged in stacks.

[0249] In vertically oriented cells, in which conventional configurations of plate types and housings are used, liquid connections between the cells can be a source of energy loss and other construction problems. The horizontal configuration described and provided in accordance with embodiments of the invention, with the filling / overflow connection described, can minimize or reduce these problems by means of an easily assembled injection molded plastic part.

[0250] The ease of assembly, modularity and scalability of this battery design is also clearly seen compared to the difficulties associated with conventional battery assemblies (see FIG. 5).

[0251] FIG. 4B illustrates an additional system for maintaining a constant electrolyte level within a plurality of stacked cells in accordance with another embodiment of the invention. The liquid battery electrolyte management system with gravity flow may include two separate systems. The first system may include a transfer station with electrolyte charging device. The second system may include a gravity flow metal anode accumulator, such as a gravitational zinc-air accumulator.

[0252] An electrolyte loading device and a transfer pump may be provided in accordance with an embodiment of the invention. The charging device can be electrically connected to a charging plug, which in turn can be connected to an energy source such as a grid / private power plant. A rectifier can be provided to convert AC electricity from the energy source to DC for charging the battery. The transfusion system with the electrolyte loading device can be used for current petrol stations, applications in residential buildings or the vehicle fleet. It can be introduced into pre-existing structures. The transfer pump may comprise one or more electrolyte conducting elements A, B, which may be a thick-walled pipe, thin-walled pipe, channel or any other fluid passageway for transferring the aqueous electrolyte. The first electrolyte carrying element may be the electrolyte supply element A. The second conducting element may be the electrolyte return B element. The electrolyte can flow from the electrolyte loading device and the transfer pump in the electrolyte supply and can flow to the electrolyte loading device and the transfer pump in the electrolyte return. In some embodiments, a pump, valve, pressure differential, or any other mechanism for causing and / or causing electrolyte flow may be provided. In some embodiments, a valve, switch, or locking mechanism may be provided that can stop and / or trigger electrolyte flow.

[0253] A metal anode battery with gravity assisted electrolyte flow may include a tube A for refilling electrolyte, spent electrolyte return pipe B, regulating valve C, electronic D controller, E pump supply line to the electrolyte storage tank F, supply cable for upper G manifolds, H1 valves 112 upper power adjustment, upper controller 11, 12 electrolyte flow, J-1 connections, J-2 J-3 storage tank K and electrolyte return line from storage tank L. In some embodiments, in the gravity-assisted flow design, gravity can push the electrolyte through the cells without having to pump the electrolyte to push through the cells. No capillary agent is required for the overflow structure of the electrolyte with gravity flow. [0254] Electrolyte filling tube A can supply liquid electrolyte to a metal anode battery with gravity flow. The regulating valve C can determine whether the electrolyte is to be delivered to the battery with a metal anode and what the electrolyte / flow velocity should be. The control valve can be directed by the electronic control D which provides instructions for the control valve. These instructions can determine which electrolyte flow the regulating valve will allow. Instructions can be provided automatically from the controller. The controller may or may not communicate with an external processor that may provide instructions to the controller. In some embodiments, the controller may have a user interface or may communicate with an external device that may have a user interface. In some embodiments, the user may be able to communicate with the user interface and may provide instructions to the controller that may affect the instructions provided to the control valve.

[0255] In some embodiments, the metal-air accumulator may have an E pump that can assist in electrolyte flow and circulation. In some embodiments, the pump may be inside a storage tank K in a metal anode battery. The electrolyte return line from the storage tank L can supply electrolyte from the storage tank K to the control valve C. The electrolyte return line from the storage tank can be connected to the pump. The pump can force electrolyte to flow through the electrolyte return line to the control valve. The electronic controller may provide instructions to the control valve, which may determine whether the electrolyte can be recycled and / or the flow rate at which the electrolyte can be recycled.

[0256] A feed line may be provided to the storage tank F. The electrolyte can flow from the control valve C to the storage tank K. You can also supply the power cord to the upper G manifolds. The electrolyte can flow from the control valve to the upper manifolds. In some embodiments, one manifold may be provided. In other embodiments, a plurality of upper manifolds may be provided. The upper manifolds may or may not be in flow connection with each other. In some embodiments, the electrolyte supplied through the power line G can be regulated by one or more valves H1, H2 regulating the upper supply. In some embodiments, a regulating valve may be provided for each upper manifold. A regulating valve can regulate the electrolyte flow to each upper manifold. The electronic controller D can communicate with the upper supply control valves. The electronic controller can provide instructions for upper power control valves. In some embodiments, the instructions provided by the electronic controller may be provided by a wired connection or may be provided wirelessly.

[0257] In some embodiments, the upper electrolyte flow controllers 11, 12 can regulate the electrolyte flow from the upper manifold to the cells below. Flow controllers can break down the electrolyte into small drops that do not form a continuous electrically conductive stream. Flow controllers can regulate the speed of fluid transferred from the upper manifold to the underlying links.

[0258] In some embodiments, the upper manifold and / or storage tank K may have ports J-1, J-2, J-3. In some implementations, these connections can communicate with an electronic D controller. In some embodiments, the terminals may provide access to perform one or more measurements. Measurements can be transferred to an electronic controller that can provide instructions to other parts of the electrolyte management system. For example, based on these measurements, the electronic controller may cause adjustment of the electrolyte flow rate, adjustment of the electrolyte temperature, adjustment of the electrolyte pH or adjustment of the electrolyte composition.

[0259] An electrical connection may be provided in the battery system. For example, an electrical connection can be provided on the (+) side of the battery and an electrical connection can be provided on the (-) side of the battery, and can be connected to a second charging plug. The charging plug 2 can be connected to a wall outlet such as a private network / power plant. An AC to DC rectifier can be supplied that can convert AC from a private network / power plant to DC for charging batteries. An inverter may or may not be provided that can convert DC from batteries to AC when the batteries are discharged.

[0260] In some embodiments, the voltage of the battery system can be monitored. In some embodiments, the voltage of the entire system can be monitored or the voltage of each module can be monitored individually. When the voltage drops unexpectedly, it may indicate a problem with one or more cells. In some embodiments, the system may increase the electrolyte flow rate when the voltage drops.

[0261] In some embodiments, one or more battery and / or electrolyte properties may be monitored at a single point. For example, electrolyte pH, electrolyte temperature, electrolyte composition can be measured at a single point, such as inside a storage tank. The invention may include a simplified monitoring system that can determine whether the system needs customization without the need for expensive and complex detection systems.

VIII. Additives for Improving Zinc Plate Quality and Forming Insoluble Zinc Compounds [0262] Internal resistance (IR) losses can be kept low by applying a good quality zinc coating by plating during each recharge cycle. The key factor in the longevity of this cell is that it does not have to be the specific shape of the electrode. In this battery electrolyte, the continuously repeated cell cycle does not damage the metal electrode. The battery system may contain any number of well-known additives that can improve the deposition of zinc on the metal electrode. Examples of additives may include, but are not limited to, polyethylene glycol with different molecular weights and / or thiourea. With these additives, a fresh, smooth, even, well conductive zinc coating can be applied by plating during each cell recharge cycle. This zinc layer is therefore readily available to easily oxidize and form dissolved zinc ions the next time the cell is discharged. In this battery system, no exact physical shape is required when zinc plating. Because gravity helps keep embedded or applied by zinc plating in place, damage to the metal electrode (quite common in other battery systems) can now be minimized or reduced as an emergency mode. This helps to achieve a very long battery life. [0263] Another embodiment may include other additives that would cause the zinc ions that are produced (during oxidation on the metal electrode during cell discharge) to remain in close proximity to the metal zinc electrode or metal current collector. This is important because these zinc compounds will then be easily reduced electrically (without excessive migration) during cell charging. It would therefore be useful to have a water-soluble electrolyte additive that (being in contact with Zn ions)²⁺ formed on a metal electrode) can form insoluble zinc compounds that can precipitate at the bottom of horizontally oriented cells. Insoluble zinc compounds may remain near the zinc electrode and be more readily available for subsequent electrochemical reduction during cell charging. The battery system may include an additive that can regulate the desired precipitation. Such additives may include any of the following water-soluble compounds. Examples of water-soluble compounds that form insoluble zinc compounds include, but are not limited to: benzoates, carbonates, iodates and stearates.

[0264] In some embodiments, additives having any of the properties described herein may include, but are not limited to, urea, thiourea, polyethylene glycol, benzoates, carbonates, iodates, stearates, a water-soluble catalytic surfactant or aloe vera, alone or in combination. In some embodiments, the addition of aloe vera extract can reduce zinc corrosion.

IX. Soluble Catalysts as an Electrolyte Additive to Improve Oxygen Formation During Recharging [0265] In addition to the solid catalyst introduced into the air contacting electrode itself, other materials such as water-soluble manganese salts can be added to improve cell efficiency during recharging. Since oxygen is produced during cell recharge, it is also useful to allow oxygen bubbles to escape easily. This can be achieved by adding surfactants that act as antifoaming agents (such as Symetykon or Dowex) to break up the resulting bubbles. The battery system may include an additive that prevents foaming and allows gas release. Additives may include one or more of the following: Simethicone, Dowex, Aloe Vera or other surfactants.

[0266] The air contacting electrode can also be mounted at a small angle to the parallel plane to help remove the four bubbles from the four cells formed by oxygen bubbles through a common filling connection near the overflow bank. In some embodiments, the expanded titanium mesh may also be equipped with a slight negative relief or impressed gas release channel circumference so that it can be ensured that most of the surface area of ​​the air contacting electrode is compatible with the electrolyte. Any air bubbles or gases can easily escape through the common fill ports. These configurations will also solve flatness tolerance problems and reduce leveling problems.)

X. Urea as an Electrolyte Additive to Eliminate Chlorine Generated [0267] The battery system may include electrolyte addition to prevent or minimize the release of chlorine and / or hypochlorite during cell recharge. Urea can be added to the aqueous battery electrolyte to regulate chlorine production. Urea and chlorine can react to form chlorides and mild gaseous products (e.g. N2, CO2 and H2). If any free chlorine is generated in the electrolyte during cell charging, it can easily react with soluble urea to form additional chloride (which is already a component of the electrolyte). The gases produced from the reaction of chlorine with urea are not dangerous and can be safely removed. If urea is added to the electrolyte and is not replenished, when the cells are charged (and if chlorine gas forms), the urea may react with the chlorine produced, run out and will not be available to remove any chlorine gas produced during subsequent charging cycles.

[0268] In the cell design provided in accordance with the embodiment of the invention, the electrolytes can be tested periodically and if the chlorine levels are above a predetermined level, additional urea may be added as required. In some embodiments, the electrolytes can be tested manually. In other embodiments, one or more sensors may be provided for automatically testing chlorine levels and, if necessary, adding additional urea to react with and remove chlorine. In some embodiments, urea can be added manually as needed. In alternative forms, urea may be added automatically when chlorine levels are above a predetermined level. In some embodiments, the predetermined level may be in the range of 5 wt% urea, but will usually be a few ppm urea.

[0269] In some embodiments, the battery electrolyte system may contain an additive that can prevent the release of hydrogen during cell charge. This additive may include, but is not limited to, chloride salts with high hydrogen concentration and overpotential, such as tin chloride, lead chloride, mercury hydride, cadmium chloride or bismuth chloride.

XI. Fast Recharging with Zinc / Electrolyte Suspension [0270] Due to the horizontal design of the cell, a system can be provided in which the cells can be quickly recharged (e.g. for long range mobile applications). Zinc chloride particles formed during discharge can be quickly removed from the cells by suctioning this suspension into a waste tank or into a tank with blades. This spent electrolyte fluid can be replaced with fresh zinc pellets in the electrolyte suspension, which can be pumped back to a horizontal cell. Solid zinc particles can settle on the bottom of the cell (metal electrode). It is expected that this mechanical top-up will take several minutes.

[0271] In some embodiments, as shown in FIG. 4B, one or more horizontal cells may be located within the housing or may form part of a battery cover. The cover can be connected to the tank. In some embodiments, the spent electrolyte liquid can be returned to the tank. The electrolyte liquid can be recycled through a thick-walled pipe, thin-walled pipe, duct, return line or any other fluid transfer device. In some embodiments, the reservoir may deliver electrolyte fluid to the enclosure. The electrolyte can be delivered through a thick-walled pipe, thin-walled pipe, duct, power cord or any other fluid transfer device. In some embodiments, the same reservoir may take in spent electrolyte fluid and provide fresh electrolyte fluid. The electrolyte liquid can then be cycled within the system. In some embodiments, the tank may have one or more treatment processes in which the spent electrolyte fluid can be treated before being returned to the enclosure. For example, fresh zinc pellets can be added to the electrolyte. In other forms, various reservoirs can be used to receive spent electrolyte fluid and supply fresh electrolyte fluid. Fresh electrolyte can be supplied to the system, and spent electrolyte can be removed from the system.

[0272] The zinc chloride particles from the cell used can be regenerated locally or in a certain district plant (equivalent to a refinery or tank storage area) by well-known electrochemical techniques. Such a modification would transform this system from what was typically envisaged as a battery to a type of larger flow cell or to a zinc air fuel cell. However, all of the above advantages would still be available and a longer discharge cycle could be achieved than a discharge cycle that would only be available from the amount of zinc that would fit into each cell without external zinc circulation. Another method of refueling can be described as pumping electrolyte, where the electrolyte that has decomposed can be replaced with fresh electrolyte for quick and convenient refueling, just like in traditional pumping stations.

XII. Metal Anode Battery Housing and Assembly [0273] As previously described, the metal anode battery system may include a battery cover. This sheath may have any number of configurations that may contain one or more closed individual cells. In some embodiments, the cell itself may form part of the shield. For example, the cells can be stacked so that the cell housings can form part of the cover. In some embodiments, the cover may be liquid tight. For example, the cover may be liquid tight and / or air tight. In some embodiments, the sheath may include one or more venting mechanisms.

A. Plastic casing with a shared four-cell "four" and electrolyte filling / discharge connection system [0274] The plastic casing system and design for the cell can be optimized or improved in terms of spatial performance, strength, formability and minimized or reduced internal losses resistance due to reduced resistance between the cells.

[0275] The cell housing design, according to an embodiment of the invention, may include a common centralized electrolyte management system which may be shared by four individually enclosed, horizontally oriented cells. In other embodiments, the centralized electrolyte management system may be shared by any number of cells including, but not limited to, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty or more links. This design can enable optimal "centralized" spatial distribution, physical stacking, and electrical communication of the manifold system. [0276] FIG. 5 shows an example of a battery stack configuration for an energy storage system. The outer walls of the enclosures 500a, 500b, 500c, 500d made of plastic may form a shield wall 502. In some embodiments, the four cells 504a, 504b, 504c, 504d can form a quadruple 504 with a shared centralized electrolyte management system 506.

[0277] Any number of cells can be stacked on top of each other. For example, four cells 504c, 504e, 504f, 504g can be stacked on top of each other. In some embodiments, one or more, two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more, twelve or more, fifteen or more, twenty or more, thirty or more, or fifty or more cells can be stacked on top of each other. One or more air flow lines 508a, 508b, 508c, 508d can be provided for each cell. In order to achieve the desired voltage, many vertically stacked cells can be selected. If the vertically stacked cells are connected in series, the number of vertically stacked cells may correspond to an increased voltage level. As described elsewhere here, a centroid can be used to create a serial connection between the cells.

[0278] Any number of fours or stacks of fours may be provided adjacent. For example, the first four 504 may be adjacent to the second four 510. One or more rows of fours and / or one or more columns of fours may be provided to the energy storage system. In some embodiments, the energy storage system may contain fours in the ixj system, where i and j are any integers greater than or equal to 1, including, but not limited to, 1, 2, 3.4, 5, 6, 7, 7 , 8, 9, 10, 11, 12, 13, 14, 15 or more. In other embodiments, the links or fours may have stepped configurations, concentric configurations, or may be placed in any manner relative to each other. Slots may or may not be provided between adjacent links or fours. Alternatively, adjacent links and / or fours may be electrically connected to each other. In some embodiments, one or more links, or one or more fours, can share a common housing with an adjacent link or four. In other forms, each link or quadruple may have its own housing, which may or may not contact the housing of an adjacent link or four.

[0279] As discussed previously, any number of cells can share a common centralized liquid electrolyte management system. Four quadrilateral cells can have a common centralized electrolyte management system, forming a four. In other examples, six triangular cells may share a common centralized electrolyte management system or three hexagonal cells may share a joint centralized electrolyte management system. Any combination of cell shapes can be used, with the corner of one or more cells sharing a common centralized electrolyte management system. All references to fours can also be applied to other numbers or cell configurations that can share a common centralized electrolyte management system. Horizontal and / or vertical cross conductive connections can be provided. This can ensure connection redundancy.

B. Unique Design of the Gravity Controlled Branch Droplet System [0280] FIG. 6 shows an example of a centralized electrolyte management system for an energy storage system in accordance with an embodiment of the invention. Many cells 600a, 600b, 600c may have a common electrolyte management system. The electrolyte management system may include an edge 602a, 602b, 602c for each cell. The edge can help keep liquid electrolyte inside the cell. The electrolyte management system may also include one or more inclined or vertical parts 604a, 604b, 604c. The sloped or vertical part can direct the electrolyte to flow into the cell. In some embodiments, the combination of the edge and the inclined or vertical portion can capture the electrolyte delivered from the above cell. In some embodiments, one or more supporting protuberances 606a, 606b, 606c may be provided. The centralized electrolyte management system may also include prismatic protrusions 608a, 608b, 608c that will allow the overflowing electrolyte skapswa44 not to the underlying cells and / or the underlying electrolyte capture tank.

[0281] In one example, the electrolyte liquid may be captured by the overflow edge 602a of the first cell 600a. The electrolyte fluid may flow down the sloping or vertical portion 604a and remain inside the cell. If the liquid electrolyte spills over the first link, it may flow over the overflow edge and into the prismatic relief 608a. After flowing through the prismatic protrusion, the liquid will be captured by the edge 602d and the sloping or vertical portion 604d of the second link 600d located below the first link. The electrolyte can now be captured and contained within the second cell. If the second cell is overfilled or then overfilled, the electrolyte fluid may flow through the prismatic protrusion 608d of the second cell and may be captured by the third cell 600e or may continue to flow down to the additional cells below.

[0282] During the initial filling of the battery system with liquid electrolyte, the cells at the top may be filled first, and then the liquid electrolyte may overflow to the underlying cells or fours, which may then overflow to further underlying cells or fours, regardless of number of vertical cell layers supplied. Finally, all cells in a vertical stack configuration can be filled with electrolyte, and excess electrolyte can be captured by the bottom tray shelf below the cells.

[0283] Each of the elements of the electrolyte management system may be integrated into the cell housing or may be separate or detachable from the cell housing. In some embodiments, the components may be injection molded.

[0284] The electrolyte management system can continuously manage the levels of liquid electrolyte in each of the four-cell "fours" to ensure constant and even electrical contact with the bottom of each air electrode. A sufficient amount of electrolyte can be delivered to the cells so that the electrolytes can contact the bottom (e.g. 610a) an air contacting electrode. In some embodiments, the bottom portion may be a metal electrode / anode. In other embodiments, to ensure electrolyte contact with the lower portion 612a on the upper portion of the aerated electrolyte, a sufficient amount of electrolyte may or may not be supplied to the cell. The lower portion of the air contacting electrode may be a cathode during discharge.

[0285] FIG. 3 provides an additional view of a cell having an electrolyte management system in the corner.

[0286] In preferred embodiments, the prismatic protuberance or edge may be configured to break or disconnect any potential connection of the conductive liquid flowing between the cells. The prismatic protuberance can break apart electrolytic liquid into separate small droplets. The prismatic relief can regulate the flow rate of any overflowing electrolyte.

[0287] The electrolyte management system may be useful to enable effective management of electrolyte overflow. The overflowing electrolyte can be intercepted by the cells below or can flow down until it is intercepted by the tank below.

[0288] The electrolyte management system may also allow unwanted produced gases to be safely discharged. In some embodiments, these gases can be vented through conduits generated by the prismatic parts, both up and down.

[0289] Preferably, the electrolyte management system can supplement the cells with liquid electrolyte by means of a gravity-controlled wastewater system. Cells can be supplemented by overflow from cells located above them or from an electrolyte source. For example, as shown in FIG. 4A, the electrolyte can be supplied to the upper storage tank. The electrolyte can be delivered to the cells or storage tank in any other way.

[0290] As envisaged in embodiments of the invention, gravity assisted overflow with a common refill connection for each cell can be widespread and used in any other energy storage device in which the levels of liquid electrolyte may change during discharge and charging. Such liquid management systems need not be limited to metal-air cells, such as zinc-air cells described herein. Other types of energy storage cells can also benefit from using similar liquid management systems. The levels of liquid electrolyte can be automatically adjusted so that the liquid only touches the bottom of each individual electrode in contact with air.

[0291] An additional modification of this design involves the production of each cell with a recess recess on one side. This cavity can act as a liquid reservoir, where excess electrolyte volumes can be safely stored when needed. When the electrolyte volumes decrease, excess liquid stored in this cavity can automatically flow by gravity and be used to refill the cell, thus ensuring that all parts from the side facing the electrolyte (bottom part) of the electrode contacting the air remain in contact with the liquid electrolyte.

C. Packed Construction for Reliability [0292] FIG. 5 provides a battery stack configuration view. As previously described, in some embodiments, the outer surfaces of the cell housings may form a sheath. In some embodiments, all critical sealing surfaces may be under vertical compressive load to increase long-term seal reliability. For example, a compressive load can be applied to a cell stack that can distribute this compressive load to the housings. This causes the housings to be squeezed together and form a seal. Compressive load can be delivered in the direction in which the cell stack is compressed together. The compressive load can be delivered in a direction perpendicular to the plane formed by the metal electrode or the electrode in contact with the air in the cell. In some embodiments, the compressive load may be provided in a vertical direction.

[0293] Centroid assemblies can be layered between respective plastic housings to produce rows of separately sealed links. As discussed earlier, centroids can be made when the metal electrode of one cell is electrically connected to the electrode contacting the air of another cell. In one embodiment, this electrical connection can be formed when the metal electrode is clamped around the air-contacting electrode. This may allow serial connection between the cells. In some embodiments, a compressive force may be applied between the links. Compressive force can be applied to the connection between the metal electrode and the air contacting electrode. The application of a force that connects the metal electrode and the air contacting electrode can improve the electrical connection between the metal electrode and the air contacting electrode. In some embodiments, the contact point of the metal electrode and the air contacting electrode may be sandwiched between plastic housings, and the compressive load may provide a compressive force between the housings and the contacts. A fluid-tight seal can be created that can prevent electrolyte flow from one cell to the other through contact between the housing and the centroid. This seal can be made or reinforced with glue.

[0294] The outer and inner walls of the partitions (which may be formed by cell housings) can be structural elements designed to properly accommodate and seal the inner working elements of each cell, and to apply compressive loads to critical cell connections and sealing surfaces. This provides an easy-to-assemble, reliable structure and a favorable structural arrangement when individual links are stacked vertically. In FIG. 1 and FIG. 2 shows how individual cells can be stacked vertically. In some embodiments, the stack can be loaded with a compressive force that can be applied to housings and / or connections between metal electrodes and air contacting electrodes.

D. Metal electrode, subassembly with air contacting electrode [0295] FIG. 1 shows the connection between a metal electrode and an air contacting electrode. In some embodiments, the assembly method consists of folding by pressing a metal electrode onto an air-contacting electrode, creating an air omega profile that allows it to pass through. In some embodiments, the metal electrode may be clamped over the air contacting electrode such that part of the metal electrode contacts the edge on the first side of the air contacting electrode and the edge on the first side of the air contacting electrode. In other embodiments, the air contacting electrode may be clamped onto the metal electrode such that part of the air contacting electrode contacts the edge on the first side of the metal electrode and the edge on the first side of the metal electrode. The metal electrode and the air contacting electrode can be clamped together in any way so that they are bent or folded relative to each other in various configurations. In some embodiments, they are clamped or otherwise connected to each other so that they contact each other without requiring any folds or folds. Other methods of making the electrical connection may be used as mentioned above. [0296] Various materials can be used in the electrode assembly contacting the metal anode, which are clamped to form an electrical flow connection along both sides of the air path. In some embodiments, examples of the metal electrode materials may include zinc (such as zinc amalgam powder), or mercury. Examples of materials for the air contacting electrode may include carbon, Teflon or manganese.

[0297] The electrode assembly may be provided where the metal electrode provides a sealed floor above the electrolyte reservoir, while the air contacting electrode forms a sealed cover for the underlying electrolyte reservoir. For example, as shown in FIG. 1, the metal electrode 104a may form the floor of the electrolyte reservoir 106a. The air contacting electrode 102a may form a cover for the electrolyte reservoir. The metal electrode and / or the air contacting electrode may be sealed.

[0298] The centroid formed by the metal electrode and the air contacting electrode can have any dimensions. One or more of these dimensions (e.g., length or width) may be about ('A', Λ "1", 2 ", 3", 4 ", 5", 6 ", 7", 8 ", 9" , 10 ", 11", 12 ")" A. 1.27, 2.54, 5.08, 7.62, 10.16, 12.7, 15.24, 17.78, 20.32, 22 , 86, 25.4, 27.94,

30.48 cm or more.

E. Cross Conductive Structures Between Links [0299] FIG. 7 shows an additional view of the battery stack configuration with metal electrode - air contact electrode connections. A metal electrode - air contacting electrode configuration can be provided where adjacent clamped edges or other centroid extensions overlap or touch, creating a repetitive, modular and electrically connected horizontal and vertical serial configuration.

[0300] The first cell may include housing members 700a, 700c and may have a metal electrode 702a. The metal electrode can be clamped around the air-contacting electrode 704b underneath the cell. In some embodiments, the metal electrode of the adjacent cell 702c may be clamped around the air-contacting electrode of the underlying cell 704d. In some embodiments, the electrical connection formed by the metal electrode 702a and the air contacting electrode 704b can communicate electrically with the electric connection formed by the metal electrode 704c and the air contacting electrode 704d. For example, one of the metal electrodes 702c may be in contact with the other metal electrode 702a. Alternatively, the electrical connection between adjacent links can be formed by any combination of metal electrodes and / or air contacting electrodes that contact each other. In some embodiments, the electrical connections between the top and bottom cells and adjacent cells (e.g. connection between 702c, 704d, 702a, 704b) can be provided between enclosures (e.g. 700c, 700d).

[0301] FIG. 7 shows an example of how metal and air contacting electrodes can create electrical connections by crimping and folding. However, any combination of connections between metal electrodes and air contacting electrodes that are superimposed or in contact with each other may be used in accordance with various embodiments of the invention. The positions of the metal electrodes and the air contacting electrodes may be reversed in alternative embodiments of the invention, and any discussion of the position of the metal electrodes may refer to the positions of the air contacting electrodes and vice versa.

[0302] Overlapping or otherwise susceptible edges may allow series or series-parallel electrical connection for reliability, simplicity and flexibility of the system. For example, one of the advantages of such a system may be that less wires and connection points are needed because each row in the cell housing can be electrically connected in series with overlapping crimped edges.

[0303] FIG. 9A provides a bottom view of the cell housing assembly with electrical connections. One or more cells 900a, 900b, 900c, 900d can form a four with a common electrolyte management system 902. The bottom of the cell can be made of a metal electrode. One or more elements 904a, 904b, 904c, 904d, 906a, 906b of the housing separating the cells can be provided. In some embodiments, electrical connections for adjacent cells may be provided between the cells. For example, between two or more links in a row, electrical connections can be provided, such as between the first link 900a and the second link 900b. An electrical connection can be made near the 904a housing between the cells. Electrical connections can be made between two or more links within the column, such as between the first link 900a and the second link 900c. Electrical connections can be made between the cells near housing 906a. Electrical connections can be provided for any combination of adjacent links within a row or column. [0304] In some embodiments, no electrical connections are provided between adjacent cells. In some embodiments, electrical connections can only be provided between the cells on top and those underneath forming a stack.

[0305] FIG. 9B shows one view of the housing assembly and one or more centroid. The 880 housing can be provided for one or more individual cells or fours, or multiple individual cells or fours. One or more centroid 882a, 882b may be made of a metal electrode 884 and an air contacting electrode 886. Centroid can be shaped to fit inside the housing. In some embodiments, the housing may rest on the centroids so that the side portion of the housing forms the cell wall and the centroid metal electrode forms the cell floor. Many adjacent centroids, e.g. 882a, 882b can be electrically connected to each other. For example, a centroid may have a point where the metal electrode and the air contacting electrode touch each other 888. The point of contact of the first link may be in contact with the point of contact of the second link. In some embodiments, the centroid may be formed such that an air channel 890 is provided between the metal electrode and the air contacting electrode.

[0306] Housing 880 may include an electrolyte distribution assembly 892 that may be integrally formed in the housing. The electrolyte distribution assembly may include a gap 894, which may allow the electrolyte to flow to the underlying cells. The electrolyte distribution assembly may include an overflow edge 896 that may determine when the electrolyte overflows into the gap. In some embodiments, the height of the overflow edge may provide tolerance when the cells or the entire battery system is inclined. Even if the entire battery system is sloped, if the overflow edge is high enough, enough electrolyte will be retained inside the cells before it overflows.

[0307] The housing may also include a shelf 898 that may protrude from the housing. The 884 metal electrode may contact the shelf. In some embodiments, a fluid tight seal may be formed between the metal electrode and the shelf. The contact point between the metal electrode and the air contacting electrode 888 may contact the bottom of the housing 881. The bottom of the housing can rest on top of the contact point. A fluid tight connection may or may not be formed. The lower housing portion 883 may rest on top of the contact point formed between adjacent centroids.

F. Stacking Configuration and Modular Assemblies [0308] FIG. 5 shows a design in which one plastic casing element is used, which essentially allows layering of multiple centroid between two common casings. This can advantageously provide a simplified design. For example, as shown, a housing forming a grid pattern may be provided which may include multiple cells. Enclosures with a grid pattern can be stacked on top of each other. In some embodiments, the mesh pattern enclosures can be made from a single integral part. Alternatively, mesh pattern housings can be made of many parts that can be combined with each other. Many parts may or may not be separable. Centroids 512a, 512b can be provided between enclosures 514a, 514b, 514c.

[0309] The housing design may include a water management system. A water management system may be provided in FIG. 4, which can represent water inlets, elevated overflow connections and prismatic drain edges, as previously described. A water management system can be used to provide the desired electrolyte level within one or more cells.

[0310] After stacking, the plastic housing construction can form a series of vertical thin-walled or thick-walled pipes that allow water to overflow, droplet electrolyte replenishment, and gas evacuation. As previously discussed with reference to FIG. 4 and FIG. 6, an electrolyte management system can be provided. When the housings are stacked on top of each other, an electrolyte management system can be provided for cell stacks.

[0311] The configuration of the stacked housing assembly can be both modular and effective. Plastic parts can be adapted to fit the shape of the metal electrode below and the air contact electrode above the cell below it, which can allow modular configuration with fewer parts. FIG. 1 and FIG. 2 show an example of a cell stack with components in housings that can be formed to match the connection of a metal electrode and an air contacting electrode. Depending on the shape of the connection between the metal electrode and the air-contacting electrode, the housings can be shaped to match the shape of the connection. In some embodiments, one or more protrusions, grooves, channels, protrusions, or holes may be provided on the plastic housing to provide the appropriate shape of the metal electrode and air contact electrode. In some embodiments, the complementary shape may prevent the housing from sliding horizontally in one or more directions. Each element may be integral with the cell or may be separable from the cell. In some embodiments, the housing components may be injection molded.

G. Modular assembly and use configuration [0312] Multiple battery configurations can be obtained by scaling the housing structure up or down. For example, the housing design may include a single cell housing, a four-cell housing, or multiple fours in a single housing. Housing construction for each grouping (e.g. single link, four links, many fours) can be made from a single integral part. A lternatywnie, the construction of the housing can comprise a plurality of parts.

[0313] In some embodiments, multiple enclosures adjacent to each other may also be provided. For example, many single cell housings, cell quadruple housings, or multiple quadruple housings can be provided adjacent. Enclosures supplied as adjacent may or may not be connected to each other by a connector. In some embodiments, force can be provided to hold the housings relative to each other. [0314] The enclosures can be stacked to any desired height depending on energy and storage needs. Any number of enclosures can be stacked on top of each other. For example, one or more two or more three or more four or more five or more six or more seven or more eight or more nine or more ten or more twelve or more fifteen or more twenty or more thirty or more sixty or more ninety or more, 120 or more or 150, or more housings can be stacked on top of each other. In some embodiments, each enclosure may have approximately 0.175, 0.635, 1.27, 2.54, 5.08, 7.62, 10.16, 12.7, 15.24, 17.78, 20.32, 22 , 86, 25.4 or 30.48 cm (1/8 ", 1/4", 1/2 ", 3/4", 1 ", 1.25", 1.5 ", 2", 2, 5 ", 3", 4 ", 5", 6 ", 8", 10 "or 12") in height. In some embodiments, the total height of the stack stack can be on the order of about 2.54 or more cm (inches), 7.62 (3) or more cm (inches), 15.24 (six) or more cm (inches), 30, 48 (1) or more cm (feet), 60,96 (2) or cm (more feet),

91.44 (3) or more cm (feet), 152.4 (5) or more cm (feet), 304.8 (10) or more feet or 609.6 (20) or more cm (feet).

[0315] Stacks of individual housings can be oriented in different directions to optimize air circulation. For example, air ducts may be provided between the cells. In some embodiments, air channels may be provided between the cells. For example, a continuous air channel may be formed between adjacent links. Air channels may be provided for cell columns and / or for cell rows. In some embodiments, these air channels may be parallel to each other. In other embodiments, one or more air channels may be perpendicular to each other. In some embodiments, the air channels may be formed in a straight line or in other forms the air channels may have arches or curvatures. In some embodiments, where the cells may be slightly inclined, the air channels may be substantially horizontally oriented, but have a slight rise and fall to adapt to the inclination of the cells. The air can flow in the same direction in parallel air ducts or it can flow in opposite directions. In some embodiments, the air channel may be restricted to one level. In other embodiments, channels may be provided that may allow air channel to be provided at multiple stack levels. Any combination of these configurations can be used. A stack or series of stacks can be used in different configurations and mounted in different covers. For example, stack heights may vary. Similarly, the number of cells delivered per stack level may vary. In some embodiments, individual cell sizes or shapes may be the same, while in other embodiments, the individual cell sizes or shapes may be different. The sizes of covers may vary depending on the size of the stacks. For example, a general energy storage system may have one or more dimensions (e.g. height, width, length) on the order of millimeter (mm), centimeter (cm) or meter (m) (inches, feet, tens of feet or hundreds of feet). Each dimension can be in the same order of magnitude, or it can be in different orders of magnitude. The stack or series of stacks can be configured as a fuel cell system by replacing or replenishing the electrolyte and packaging of said support systems. For example, the zinc-air fuel cell system may include adding metallic zinc and removing zinc oxide. As previously mentioned, zinc pellets can be added to the electrolyte. Zinc oxide or zinc chloride can be disposed of in a waste container.

H. Insulated cargo container and use of the HVAC machine [0316] FIG. 8A shows an example of using an insulated cargo container and HVAC device for a cell stack according to an embodiment of the invention. The 802 shield may contain multiple modules 800a, 800b, 800c. Each module may have an upper shelf 804, one or more stacks of 806 links (which may contain one or more levels / layers of individual links, four links and / or any number of links), and a lower shelf or base 808. See also FIG. 8H. Each cell stack can have a manifold, through which the electrolyte can be sent or disconnected to a given stack or section of the stack. Similarly, electrical connections can be segregated and disconnected to specific stacks.

[0317] In one example, 16 modules 800a, 800b, 800c 960 quadruple cells can be provided. Two rows can be provided, each with eight modules. In various embodiments of the invention, any number of modules can be provided, including, but not exclusively one or more two or more three or more four or more five or more six or more seven or more eight or more nine or more ten or more twelve or more fifteen or more twenty or more thirty or more fifty or more or one hundred or more modules. In some embodiments, these modules may be arranged in one or more rows and / or one or more columns. In some embodiments, these modules may be arranged in the form of an array. The cover 802 may be shaped to fit into the modules. In some embodiments, the sheath may be about 12,192, 13,716, 15.24 or 15.9696 m (40, 45, 50 or 52 feet) long.

[0318] The module may have any dimensions. In some embodiments, the module may have dimensions of about 1.27 meters (50 inches) by 1.11 meters (44 inches). In one example, the module may contain 80 or 120 or more stacks or 15 or more quadruple links. However, the module can be created from any number of levels / layers in stacks, including, but not exclusively 1 or more layers, 2 or more layers, 3 or more layers, 5 or more layers, 10 or more layers, 20 or more layers, thirty or more layers, 40 or more layers, 50 or more layers, 60 or more layers, 70 or more layers, 80 or more layers, 90 or more layers, 100 or more layers, 120 or more layers, 150 or more layers or 200 or more layers. Each layer of the stack can contain any number of single or quadruple links. For example, each stack level / layer may contain 1 or more, 2 or more 3 or more 4 or more 5 or more 6 or more 7 or more 8 or more 9 or more 10 or more 12 or more 14 or more 16 or more 20 or more 25 or more thirty or more 36 or more 40 or more 50 or more or 60 or more individual links or quad links per level / layer.

[0319] In some embodiments, the module may include an upper shelf 804. The upper shelf may be configured to receive electrolyte. In some embodiments, the upper shelf may be configured to distribute the electrolyte to one or more cells. The top shelf can be in connection with allowing flow with the electrolyte management systems in the cells. In some embodiments, the top shelf may be in fluid communication with one or more links. The top shelf may contain one or more protrusions. One or more protrusions may provide structural support for the lid over the shelf. The top shelf may contain one or more channels or grooves. In some embodiments, the top shelf may include one or more openings or conduits providing a fluid permeable connection to the underlying layers.

[0320] The module may also include a bottom shelf or stand 808. In some embodiments, the bottom shelf or stand may collect electrolyte that may overflow from the top pile. The bottom shelf or stand may contain collected electrolyte or may transfer it to another location.

[0321] The modular construction can be made to fit into various ISO standard cargo containers in an optimal way. In some embodiments, the cover may be an ISO freight container. The cover can be about 20 feet (6.1 m), 40 feet (12.2 m), 45 feet (13.7 m), 48 feet (14.6 m), and 53 feet (16.2 m). The ISO container can be approximately 12.4 m (8 ft) wide. In some embodiments, the container may be about 9 feet, 6 inches (2.9 m) or 4 feet, 3 inches (1.3 m) or 8 feet, 6 inches (2.6 m) high. The modular design can also be made to fit into any other different standard container, such as freight container. The modular design can provide the flexibility of an energy storage system to fit into pre-existing containers or structures.

[0322] For modular design, existing refrigeration and air conditioning equipment attached to insulated containers can be used as a complete HVAC solution.

[0323] Conventional cooling can be achieved by correctly positioning the cooling holes outside the housing.

[0324] In some embodiments, the battery system may include one or more battery modules, one or more electrolyte management systems, and one or more air cooling assemblies. In some embodiments, the battery module may include an upper shelf, a lower shelf, and one or more cell stacks. In some embodiments, the cell stack may include one or more layers or levels of cells. In some embodiments, one or more cell levels or layers may include a single cell, a four cell, a plurality of cells, or a plurality of cells. For example, the layer may be formed in the form of a mxn array of cells or from a mxn array of fours, where mi / or n can be independently selected from any integer greater than or equal to 1, including but not limited to 1, 2, 3, 4 , 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more. Each module may contain one or more parts of the electrolyte management system. In some embodiments, each four may share one or more parts of the electrolyte management system.

[0325] In some embodiments, the module may be a 50 kW / 300 kWh module. In other embodiments, the module may have any other power / energy. For example, the module can provide 10 kW or more, 20 kW or more, 30 kW or more, 50 kW or more, 70 kW or more, 100 kW or more, 200 kW or more, 300 kW or more, 500 kW or more, 750 kW or more, 1 MW or more, 2 MW or more, 3 MW or more, 5 MW or more,

MW or more, 20 MW or more, 50 MW or more, 100 MW or more, 200 MW or more, 500 MW or more or 1000 MW or more. The module can also supply 50 kWh or more, 100 kWh or more, 200 kWh or more, 250 kWh or more, 300 kWh or more, 350 kWh or more, 400 kWh or more, 500 kWh or more, 700 kWh or more, 1 MWh or more, 1.5 MWh or more, 2 MWh or more, 3 MWh or more, 5 MWh or more, 10 MWh or more, 20 MWh or more, 50 MWh or more, 100 MWh or more, 200 MWh or more 500 MWh or more, 1000 MWh or more, 2000 MWh or more or 5000 MWh or more.

[0326] FIG. 8B shows the bottom parts of battery modules in accordance with an embodiment of the invention. The lower portions may contain one or more 820 stacks, which may contain one or more 836 cell layers / levels. The battery module may include support 824 of the battery stack underneath the cell layers. Stack support can support the stack under the lower tank 822. The lower tank can be configured to store electrolyte that can flow from stacks. Stack support may be configured to prevent electrolyte from contacting the bottom of the stack, such as an electrode contacting air at the bottom of the stack. In other embodiments, the stack support may allow the electrolyte to contact the bottom of the stack, but may provide support to hold the stack support suspended over portions of the bottom tank.

[0327] In some embodiments, the lower electrolyte storage tank, which can be thermoformed, can absorb excess electrolyte and assist in electrolyte circulation in the battery system. For example, the lower tank may direct the electrolyte into the test tank and then into the upper tank, which may distribute the electrolyte into one or more stacks. The lower reservoir is in fluid communication with one or more fluid distribution elements 826, which may include pipes, channels, or any other fluid distribution lines known in the art.

[0328] The stack 820 inside the battery module may include one or more layers or levels 836. The level or layer may include an 830 housing. The housing can be injection molded or formed in any other way. In some embodiments, one integrally formed housing may be provided per layer or level. In other embodiments, multiple housings or separate housing parts may be provided on a layer or level. In some embodiments, the housing may include part of an electrolyte management system 832. The electrolyte management system can be integrally formed inside the housing. When the housing layers are stacked vertically, parts of the electrolyte management system can be vertically aligned and allow the electrolyte to be distributed to the 834 cells within the layers.

[0329] Link 834 can be made surrounded by a housing 830 and supported by an electrode 828. In preferred embodiments, the surface of the electrode forming the bottom of the cell may be a metal electrode. The electrolyte can flow into the cell and be supported by the electrode and contained in the housing. Any excess electrolyte may flow into the electrolyte management system 832 and may be distributed to the underlying cell or may flow all ways to the lower tank 822. [0330] FIG 8C shows a plurality of battery modules in a battery system. In some embodiments, the battery arrangement may include a cover that may include a floor 840 or base, or one or more walls 842 or coverings. As previously mentioned, in some embodiments the cover may be a standard container, such as a transport container.

[0331] The battery system may include an electrolyte management system. In certain embodiments of the invention, the electrolyte management system may include one or more tanks 844a, 844b, which may assist the circulation of electrolyte in the system or water supply or resource to provide a consistent electrolyte mixture when evaporation occurs. These tanks can help to filter the electrolyte in the system or help to supply electrolyte additives in the system. In some embodiments of the invention, one or more pumps, valves, or pressure differences, such as an overpressure source or underpressure source, may be used in the electrolyte system, thereby assisting the circulation of the electrolyte. In some embodiments of the invention, the reservoir may have an inlet and / or an outlet from the system. The inlet and / or outlet can be used to remove wastewater or filtered substances, supply additions, release gases or excess fluids, or supply fresh fluid to the system. In some embodiments, one or more electrolyte guiding elements 846 may be placed in the battery system. The electrolyte guiding element may be a pipe, a duct, or any other assembly capable of transporting fluid from the tank to the upper tanks of the stacks directly or through a manifold. Electrolyte guiding elements can transfer the electrolyte from reservoir 844a, 844b to one or more modules 850. In some embodiments, the electrolyte can be transferred to the top shelf or tank of the module. In some embodiments, the electrolyte guiding elements can be used to transfer the electrolyte from the module to the reservoir 844a, 844b. The electrolyte guiding element can transfer electrolyte from the bottom shelf or module tank to tank 844a, 844b.

[0332] The battery system may include an airflow assembly. The airflow assembly can circulate air in the battery system. In some embodiments, the airflow assembly may cause airflow in the modules. In some embodiments, the airflow assembly may cause airflow in the air tunnels between the cells. In some embodiments, one or more air tunnels may be placed between each layer of the stack. In some embodiments, the air flow tunnels may be horizontally oriented. In some embodiments, the air flow tunnels may be substantially horizontally oriented and / or may have a slight slope (e.g., 1 to 5 degrees). The airflow assembly may include a fan, pump, pressure differential, such as an overpressure source or underpressure source, or any other assembly that may cause airflow. In some embodiments, the airflow assembly may cause airflow in tunnels of one or more modules. In some embodiments, air can flow between tunnels of different modules. The cells can be configured such that air tunnels can be formed continuously between adjacent links and / or adjacent modules. In other embodiments, there may be gaps in the tunnel between the cells and / or between the modules.

[0333] In some embodiments, the battery system may also include one or more inverter assemblies 848. The inverter assembly may convert DC to AC.

[0334] FIG. 8D shows a top view of the battery system including multiple battery modules. As described earlier, a cover for the battery system can be used. The cover may include a floor 860 and / or a cover or door 862 that may include walls or ceiling. One or more 864 tanks or elements 866 carrying electrolyte such as a tube can be placed. The electrolyte guiding element can connect a reservoir with one or more 870 modules to fluid flow. In some embodiments, each module can directly connect to the possibility of fluid flow with the reservoir through the electrolyte guiding element. In some other forms, one or more modules may be directly connected to the reservoir by other modules. In some embodiments, the electrolyte guiding element may be connected to one or more modules on top of the module. The electrolyte guide may be configured to supply electrolyte to the top shelf of one or more modules.

[0335] Any number of 870 modules may be included in the battery system. For example, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, twenty one, twenty two, twenty three , twenty four, twenty five, twenty six, twenty seven, twenty eight twenty nine, thirty or more modules can be placed in the battery system. In some embodiments, the battery system may be a container with a 6-hour power supply of 1 MW. In other embodiments of the invention, the battery system may have power

100 kW, 200 kW, 300 kW, 500 kW, 700 kW, 1 MW, 2 MW, 3 MW, 5 MW, 7 MW, 10 MW,

MW, 20 MW, 30 MW or more. In some embodiments, the battery system may be a 1-hour, 2-hour, 3-hour, 4-hour, 5-hour, 6-hour, 7-hour, 8-hour, 9-hour, 10-hour, 11 system - hourly, 12-hour, 13-hour, 14-hour, 15-hour or longer.

[0336] In some embodiments, for a standard module, one or more of the following characteristics may be used: the system may have features such as 500 k - 2 MW, 2-12 MWH, and the system is expected to have a low cost . Such features are given by way of example only. They are not intended to limit the invention.

[0337] The modules may have any configuration in the battery arrangement. For example, you can place one or more rows and / or columns of modules. In some embodiments, a module matrix can be placed. For example, you can place two rows of 12 modules.

[0338] In some embodiments, the electrolyte guiding element can be a pipe that can pass over each module. In some embodiments, the pipe may be in fluid communication with each module on top of the module. The tube can carry electrolyte to the upper tray of each module. In some embodiments, the pipe can pass as a straight pipe over the first row of modules, then it can bend and twist and pass as a straight pipe over the second row of modules. Alternatively, the pipe may have any other bent or zigzag configuration.

[0339] In some embodiments, the battery system may also include one or more inverter assemblies 868. The inverter assembly may convert DC to AC.

[0340] FIG. 8E shows an example of a battery system including an airflow assembly. The battery assembly may have a container with a front end and a rear end. In some embodiments, the container may be thermally insulated and / or electrically insulated. In some embodiments, the container may be a standard container, such as those previously described, or a refrigerated container. In some embodiments, the container may be about 13.4 m (40 feet) long.

[0341] One or more modules may be included in the container. In some embodiments, up to 36 modules can be placed in a container. The modules can be arranged in a container so that two rows of modules are placed, where each row has 12 modules. So the battery layout can have a layout such that it has 12 modules deep and 2 modules wide. In some embodiments, 1800 quadruple links can be placed in a module. The module can have 120 cells per height (e.g., 120 layers or levels) and can have 15 quadruple cells per layer or level. In some embodiments, the battery system can have a total of about 50,000 quadruple cells.

[0342] FIG. 8E shows an example of an airflow assembly. The airflow assembly may be placed in the container. The floor of container A may include tees, grooves, channels, projections, ridges, or other shapes. An air manifold B may be used, or a T-floor may be used in some refrigerated containers. In some embodiments, the air in the lower manifold can flow transversely. In some embodiments, air may flow toward central passage C of the air flow assembly. In some embodiments, air can float in the central passage. One or more air tunnels D may be arranged for one or more modules. The air tunnel may have a horizontal layout. Air tunnels can be placed as part of the centroid cells. Air can flow from the central passage to one or more air tunnels that channel the air transversely between the cells.

[0343] From air tunnel D, air can crosswise to peripheral passage E. One or more perimeter transitions can be placed. In some embodiments, two peripheral transitions E, F can be placed. The air may float along the peripheral passages. The perimeter passage can be placed between module K and the container wall I. In some embodiments of the system with fan or air circulation or removal, an upper air manifold H with a housing G upper air manifold can be placed. The upper air manifold can absorb air from peripheral passages. In some embodiments, a J lock may be provided to prevent air from rising from the central passage directly into the upper air manifold. This can force some air to flow into the air tunnels. In alternative embodiments of the invention, some air may rise from the central passage to the upper manifold. In some embodiments, air can flow along the length of the upper air manifold. For example, air may flow from the side of the container from the use area to the other end of the container.

[0344] FIG. 8F is an additional view of the airflow assembly. The airflow assembly may be provided in a container. The floor of container A may include tees, grooves, channels, projections, ridges, or other shapes. Air can flow along the spaces in the floor between the floor elements. The bottom airflow passage or tunnel B can be placed. In some embodiments, the air in the lower passage may flow transversely. In some embodiments, air may flow toward central passage C of the air flow assembly. In some embodiments, air can rise from the central passage. One or more air tunnels D may be arranged for one or more modules. The air tunnel may have a horizontal layout. Air tunnels can be placed as part of the centroid cells. Air can flow from the central passage to one or more air tunnels that channel the air transversely between the cells. [0345] From air tunnel D, air can crosswise to peripheral passage E. One or more perimeter transitions can be placed. The air may float along the peripheral passages. The perimeter passage can be placed between module K and the container wall I. In some embodiments, there may be an upper air manifold J with an upper air manifold housing. The upper air manifold can absorb air from peripheral passages. In some embodiments, an H lock may be provided to prevent air from rising from the central passage directly into the upper air manifold. This can force some air to flow into the air tunnels. In alternative embodiments, some air may rise from the central passage to the upper manifold. In some embodiments, air can flow along the length of the upper air manifold. For example, air may flow from the side of the container from the use area to the other end of the container.

[0346] An upper electrolyte supply tank G can be placed as part of the module. The lower tank F receiving electrolyte can also be placed as part of the module. In some embodiments, container I may rest on surface K.

[0347] In some embodiments, the supply air may be air supplied through the floor and the bottom manifold. The supply air can then rise through the central passage and pass through air tunnels. Return air can pass through the peripheral passages and flow through the upper manifold. In alternative forms of the invention, air may flow in other directions (e.g., it may be provided from the upper manifold and may flow through air tunnels in opposite directions.

[0348] FIG. 8G shows an alternative example of an airflow configuration. In some embodiments, air can flow through the length of the container and does not need to be separated laterally. Air may or may not be recycled through the length of the container.

[0349] In some embodiments, the modules can be placed on the floor of the container. In some embodiments, the floor of the container may have a T-type floor. In some embodiments, the floor may have one or more grooves, channels, slots, projections, or ridges that can support modules, providing space below the modules. In some embodiments, air can flow into the space under the modules. This can help regulate the temperature.

[0350] In some embodiments, a usable area adjacent to the modules can be placed in the container. For example, modules can be placed in a container to provide a usable area of ​​1.8 by 2.1 m (6 by 7 feet). In some embodiments, the user may be able to access the use area. The user may be able to enter the container in the use area. In some embodiments, the use area may be located at the rear end of the container.

[0351] In some embodiments, an expansion chamber may be provided in the container. The expansion chamber may protrude from the container wall at the front end. The expansion chamber can be curved and can meet the module about halfway up. In some embodiments, the air supply may be located in one part of the expansion chamber and the air inlet may be located in the other part of the expansion chamber. For example, the air supply may be located on the underside of the expansion chamber, and the air inlet may be located on top of the expansion chamber, or vice versa. In some embodiments, the air supply may include cold, treated air. The air supply may flow in the first horizontal direction through the modules located on the supply side of the expansion chamber. For example, if the air supply is placed on the underside of the expansion chamber, the air may flow horizontally in the first direction through the bottom half of the modules. Air can flow through one or more module air tunnels.

[0352] When the air reaches the usable area at the other end of the container, the air can migrate to other parts of the modules. For example, air may rise to the upper half of the modules and flow in the other direction back to the top of the expansion chamber. In some embodiments, the second direction may be horizontal and / or may be opposite to the first direction. Air can reach the return air inlet in the upper part of the expansion chamber. The expansion chamber can be located in the front end of the container. Alternatively, the air does not need to be recycled and can be taken in through the inlet on the side of the useable container. The side of the container usable area may or may not provide a second air supply that may flow back to the first air supply. The carrier unit may also be located at the front end of the container. The carrier unit may absorb inlet air and may cool it, may change and / or maintain the air temperature, may filter the air, and / or change and / or maintain the air composition. [0353] As previously described and shown in FIG. 4A, an electrolyte circulation and treatment system may be provided, consisting of several components. In some embodiments, a separate installation balance (air and water / electrolyte management system) may be made. The electrolyte circulation and treatment system may include one or more of the following:

a) A device for deionizing and / or filtering all water before entering the system.

b) Chemical tank for introducing and mixing various salts and other chemicals with deionized water. This may be part of the electrolyte.

(c) A tank or series of tanks for measuring and treating battery electrolyte.

d) Pump or series of pumps distributing electrolyte in the battery system.

e) Various sensors measuring and monitoring the total volume, temperature, electrolyte pH levels and other measures of the system operation.

f) Supply and return lines that distribute liquid electrolyte to and from the battery.

g) Various sensors and valves to regulate the flow of liquid electrolyte and to control the electrical connections from the control box.

[0354] FIG. 8H shows an example of a battery system in a container. One or more tanks (e.g., treatment / storage tank, electrolyte tank) can be used and they can be connected into one or more modules via fluid connectors and valves. For example, the electrolyte can be supplied through a manifold and then separately divided between separate fluid connectors that carry the electrolyte to each of the modules in the system. For example, each upper module tank in the system can be connected in a manner that allows fluid to flow with the manifold and can receive fluid therefrom. In some embodiments, one or more user interfaces may be provided.

[0355] In some embodiments, an airtight wall can be placed between the modules and the rest of the container. For example, you can create a service or utility area that an operator or other user can access. For example, you can create a service door that an operator or other user can enter. In some embodiments, the service or utility area may include tanks, a user interface or an electronic control system. In one example, the hermetic wall can separate the service area or utility area from the modules.

B. Air circulation and air conditioning systems [0356] FIG. 8A shows an example of an insulated cargo container and the use of an HVAC machine according to an embodiment of the invention. The energy storage system may include an air circulation and air conditioning system composed of several components. FIG. 8E shows an example of an air circulation system.

[0357] A number of air flow expansion chambers can be used to regulate and distribute the air flow evenly between the cells. Forced air cooling can be more effective than convection, especially in combination with good internal heat sinks and the style of the enclosure design with expansion chambers. Heated air can be removed from the equipment housings by fans or blowers, which can also draw cooler air into the housing through vents. Depending on the cooling requirements, low to high volumes of air can be moved through the housing.

[0358] In some embodiments, one or more temperature sensors may be used. Based on the temperature detected by the temperature sensor, fans or blowers may vary and / or behave to regulate the air flow rate. A fan system can be used that forces air through the battery.

[0359] The system may include a fresh air replenishment and filtration system for introducing oxygen, while filtering out unwanted contaminants. In some embodiments, a higher oxygen content than in ambient air may be desired.

[0360] An HVAC system can be used that measures and regulates the air temperature inside the battery cover.

[0361] The system may also include a humidity control system that moisturizes or dehumidifies the air in the battery shell. One or more humidity sensors can be placed. The humidity control system can change and / or maintain humidity based on measurements from humidity sensors.

[0362] In some embodiments, a number of sensors can be used that communicate with various other systems.

C. Electrical connections and management [0363] An electrical system can be used that facilitates the flow of energy in the battery and distributes energy between the battery and the power grid or other energy source. In some embodiments, the electrical system may determine whether to provide energy flow between the battery and the power grid or other energy source or outlet. The electrical system can determine the direction and / or amount of energy flow between the battery and the energy source or outlet.

D. Measuring and control systems [0364] A centralized measuring system may include various sensors that are connected to a computerized control system. In some embodiments, the computerized control system may include one or more processors and memory. The computerized control system can collect measurements collected from various sensors. The computerized control system can perform one or more measurement-based calculations. You can apply any algorithm, calculation or other steps using specific media read by the computer, which may contain code, logic, instructions for performing such steps. Such computer-readable media can be stored in memory. One or more processors can access and execute such memory.

[0365] The computerized control system may be combined with various other mechanical systems. In some embodiments, the computerized control system may instruct one or more mechanical systems to perform the action. For example, a computerized control system may instruct the pump to pump a larger volume of electrolyte into the top shelf. A computerized control system may recommend something to one or more valves, which can affect the distribution of electrolyte between multiple modules. In another example, a computerized control system may cause a fan to blow more slowly. In some embodiments, the computerized control system may issue one or more instructions based on measurements obtained from one or more sensors. Any instructions can be issued by the controller over a wired or wireless connection. [0366] The computerized control system may be associated with a telephone and / or cellular communication networks. In some embodiments, the computerized control system may include a processing device, such as a computer. Any discussion of the processing device or any particular type of processing device may include, but not exclusively personal computer, server computer or handheld computer; personal digital assistants (PDAs) such as a Palm or Windows device; telephones such as mobile telephones or location-recognizable mobile telephones (such as GPS); roaming device, such as a networked roaming device; a wireless device, such as a wireless e-mail device or other device capable of wireless communication with a computer network; or any other type of network device, which can communicate over the network and make electronic transactions. In some embodiments, a computerized control system may include a plurality of devices. In some cases, the computerized control system may include a client-server architecture. In some embodiments, the processing devices may be specially programmed to perform one or more steps or calculations, or perform any algorithm. The computerized control system may communicate on any network, including but not limited to cellular communication networks, other telephone networks, local area network (LAN) or wide area network (such as the Internet). Any communication can be provided via a wired connection and / or a wireless connection. [0367] In some embodiments, the user may interact with the computerized control system. The user can be remote from the computerized control system and can communicate with the computerized control system via the network. Alternatively, the user can be connected locally on the user interface of the computerized control system.

E. Environmental installation and shell configurations [0368] In general, modular batteries and their arrangements are not limited by size, volume or scale. Normal industrial cabinets, containers, buildings and other structures can be configured to contain the battery and its systems.

[0369] The battery and its assistance systems can be configured in mobile and stationary configurations. For example, the battery and its assistance systems can be located, for example, in buildings, transport containers, ships and cars.

XIV. Fuel cell configuration [0370] In accordance with some embodiments of the invention, the energy storage system described herein can be used in a fuel cell configuration. In a fuel cell configuration, each cell can be supported by supplying inlet and drain outlet valves for transferring or transfusing electrolyte. In some embodiments, it may utilize a battery electrolyte transfer system with a gravity-based flow. For example, the supply inlet may be located above the cell and the drain outlet may be located below the cell. In other embodiments of the invention, cell groups (such as fours or layers) may be supported by a feed inlet and a drain outlet.

[0371] The fuel cell configuration may provide mechanisms for removing spent electrolyte and adding fresh electrolyte via a remote control and convenient connection or transfer.

XV. Market acceptance and adaptation scenarios [0372] An energy storage system, which may include the forms discussed elsewhere herein, can be advantageously used with green energy generators. Examples of green energy generators may include wind farms, solar farms or tidal farms. The energy storage system can also be used with traditional energy generators, such as steam generators for fossil fuels or nuclear generators. In some embodiments, the energy storage system can store energy from the generator. In other embodiments of the invention, it may be possible to supplement or move the energy generated by the generator.

[0373] An energy storage system can be used in energy distribution. For example, it can be used with regional electrical equipment, local electrical equipment, remote storage and mobile storage.

[0374] The energy storage system may also find applications in energy storage, management and reserves. For example, energy storage can be used in government and military applications, commercial and industrial applications, community and institutional applications, residential and personal applications (fuel cell or battery). In some embodiments, excess energy can be stored in an energy storage system and used when needed. The energy storage system may have an energy density such as to be located in suburban substations or urban undergrounds.

[0375] Transport applications for an energy storage system can be envisaged. For example, an energy storage system can be used to power locomotives and railways. The energy storage system can also be used to ship cargo (on land or water). The energy storage system can also be used for mass transport and bus transport. For example, the energy storage system can be provided as a fuel cell or battery in a mass transit vehicle. Similarly, the energy storage system may have automotive applications and may be provided as a fuel cell or battery for a motor vehicle. Preferably, the energy storage system on the vehicle can be recharged.

XVI. The flattened structure of the four-sided pyramidal cell compensates for changes in electrolyte volumes [0376] In rechargeable zinc-air cells, electrolyte volumes are typically not constant.

[0377] During cell discharge, when metallic (relatively high density) zinc is converted into lower density zinc compounds, electrolyte volumes may increase. When charging the cell, the reverse reaction occurs and the electrolyte volumes may decrease. Electrolyte volumes may also decrease due to water evaporation.

[0378] Such changes in electrolyte volume may adversely affect cell performance. If the electrolyte volumes become too low, there may not be enough conductive electrolyte between the metal electrode and the air contacting electrode. This can increase cell resistance, which in turn can adversely affect cell performance. Similarly, if the electrolyte volumes become too high, excess electrolyte can be forced into the pores of the air contacting electrode. The electrolyte penetrating and flooding the pores of the contacting air impedes the easy diffusion of oxygen gas (and its electrochemical reduction) inside the pores. In addition, the increased volume of electrolyte increases the pressure at the electrode contacting the air and could cause mechanical damage to the electrode. This worsens the link. [0379] Controlling these constantly changing electrolyte volumes during a full battery stack operation can be accomplished using a feedback mechanism that can automatically compensate for electrolyte volume changes. When the cells need additional electrolyte (for example, when charging the cell, when the electrolyte levels fall), the electrolyte may slowly drip from the tank into individual cells. When discharging the cell, as the electrolyte volumes increase, excess electrolyte inside the cell can be directed through the overflow connection to the storage tank.

[0380] The previously described embodiments may include a quadruple link whose horizontal construction includes a fill port and a discharge port located at a node where four horizontally arranged links meet. This fill / discharge connection with light can allow the electrolyte to drip to and from individual cells as needed. When a number of these four-cell sets are stacked on top of each other, the fill / discharge connection of the upper four-cell set can be located exactly above the lower four-cell set. In this way, the number of vertically stacked four-cell sets can use a common fill / discharge connection that is connected to a common container.

[0381] Another horizontal four-cell structure may be used in accordance with another embodiment of the invention. The horizontal design may involve assembling a four-cell set so that each link in this set is slightly oblique (inclined) upwards (on one side only) towards the fill / drain connection. This can provide physical compensation for gas evolution by facilitating gas escape.

[0382] FIG. 10 illustrates a top view (looking down) of four links (Link 1, Link 2, Link 3, Link 4) in a horizontal set. The cells can be arranged so that they share a common fill and drain connection (indicated by 0). The corner of each individual link is slightly inclined upwards in the direction of 0. Thus, the corner of each individual link furthest from 0 can be inclined downwards.

[0383] Another way to visualize this construction would be to imagine four individual links arranged as a four-sided pyramid (on the top of the pyramid there would be a point where all four links meet), but instead of a sharp upward slope like in a typical pyramid, this pyramid is flattened to tilting angles only 1-5 degrees from horizontal. The angle of inclination of each individual cell in a four-cell set can be of any value, including limited to 0.25 degrees or less, 0.5 degrees or less, 0.75 degrees or less, 1 degree or less, 2 degrees or less, 3 degrees or less, 4 degrees or less, 5 degrees or less, 6 degrees or less, 7 degrees or less, or 10 degrees or less. Preferably, each link can be tilted at the same angle, although in other embodiments of the invention individual links can be tilted at different angles. This flattened structure of the four-sided pyramid is supposed to help in electrolyte management and gas evolution during discharge / charge cycles.

[0384] This is shown in side view in FIG. 11B. Here, each of the cells 1150a, 1150b, 1150c in the stack set may be slightly inclined upwards from the level towards the filling connection. In some embodiments, a slope of about 1.5 degrees can be used. Upper water tank 1152 may have one or more downpipes 1154. Drain pipes may allow a controlled amount of electrolyte to flow from the upper water tank into the cell below. In some embodiments, down pipes with an internal diameter of 3/4 "may be used.

[0385] The structure may include one or more struts 1156 in the manifold 1158. Such a manifold may provide a gap between the upper water tank and the links below. In some embodiments, the spacer may help maintain a gap between the upper water tank and individual links. In some embodiments, the spacer may provide support between the links and the upper water tank.

[0386] One or more flow regulating elements 1166 may regulate the flow rate of electrolyte supplied from the upper water tank to the underlying cells. In some embodiments, the flow regulating element may protrude or may be arranged vertically. The flow regulating element can break the electrolyte into small drops. In some embodiments, the flow regulating element may prevent the formation of an electrical connection between the electrolyte in the upper water tank and the electrolyte in any of the individual underlying cells. A drop from the flow regulating element can be captured by the underlying link. In some embodiments, the underlying links may have a connection with an overflow portion. The flow regulating elements can be arranged vertically on the overflow part. Connections of vertically placed links can also be arranged vertically. In some embodiments, the drop may flow into the cell's electrolyte pool 1160. The electrolyte from the upper link can flow to the underlying link. In some embodiments, each cell may have a cell flow control element 1164, which may also regulate the flow of electrolyte delivered to the underlying cells. The cell flow regulating element may break the electrolyte into droplets and prevent the formation of an electrical connection between the electrolyte in the cell and the electrolyte in the underlying cell. In some embodiments, the flow regulating elements may be substantially vertically aligned with the flow regulating elements above and / or below. Alternatively, they may have step alignment or other. One or more air routes 1162 can be placed between the links.

[0387] As discussed previously, the individual cells can be tilted so that the part of the cell receiving the electrolyte can be tilted upwards. The electrolyte may flow from the part of the cell receiving the electrolyte towards the other end of the cell.

[0388] The slightly inclined orientation of the cell has many clear advantages when the cells are stacked. The first advantage is the constant and repeatable cell resistance maintained between the metal electrode and the air-contacting electrode. This helps to maintain electrolyte resistance under strict control.

[0389] A second advantage includes controlling gas bubble production. During the cell charging cycles, along with the reduction of water, oxygen gas bubbles must be emitted. Such an inclined electrode design may allow easy migration of these generated gas bubbles towards the top of the electrode - near the corner of the electrode, where they can then be safely released. Easy migration of gas bubbles to one side eliminates the potential problem of increased electrolyte resistance due to entrapped gas bubbles in the electrolyte. The sloped structure may be slightly angled to allow gas escape and facilitate slurry flow in the battery flow configuration.

[0390] The third advantage is that during the charging cycles (when the electrolyte is added from the tank to each individual cell), the inclined cell design allows easy entry and filling of each individual cell with added electrolyte.

[0391] The angle of inclination for each link need not be great. It is clear that if the inclination angles of individual cells were too steep, any electrolyte added would flow towards the bottom of the cell and flood the bottom of the electrodes in contact with air. [0392] The preferred angle of inclination may be in the range of only 1-5 degrees from horizontal. This may be low enough so that the electrolyte will not generally accumulate at the bottom of each cell, but any gas bubbles generated are deflected and rise towards the top opening of the assembly and can easily lower it.

[0393] FIG. 11A shows a top view of an energy storage system in accordance with an embodiment of the present invention. In some embodiments, the energy storage system can act as flow through a cell. Alternatively, it does not have to act as a flow through the cell. The upper water tank may have a floor of 1100. A downpipe 1102 can be placed to allow the electrolyte to flow to one or more links below. In some embodiments, one or more flow regulating elements 1104 may be used to control the flow rate of the electrolyte passing to the underlying cells. In some embodiments, the flow regulating element may break the electrolyte into small drops. In some embodiments, a flow regulating element may be provided for each of the underlying links. For example, if four horizontally oriented cells (forming a flat four) share a common electrolyte management system, four flow control elements can be used. Each flow regulating element can protrude above its own respective link. Any number of flow regulating elements may be used which may or may not correspond to the number of underlying links in the layer immediately below. For example, you can place one, two, three, four, five, six, seven, eight, nine, ten or more flow regulating elements.

[0394] The quadruple link may also have a central portion that may be oblique downwards towards the link. Any electrolyte that can fall into the middle part can flow down and into the underlying cell. In some embodiments, the central portion may be injection molded.

XVI. Example [0395] In one example, a test cell can be provided. FIG. 13 shows an example of cell voltage over time in accordance with an embodiment of the invention. A test time of 350,000 seconds was used to show that the system was operating as described.

[0396] A stable voltage range was obtained from a previously tested cell. There was no physical decay in the early cell version. For example, as shown in FIG. 13, the voltage remained relatively stable for 350,000 seconds. Mostly, the voltage was between 0.9 and 2.1 volts.