High performance energy storage devices

[0001] The present invention relates to high-performance lead-acid batteries.

[0002] There is an increasing demand for the development and introduction of vehicles that do not rely almost entirely on fossil fuels to combat air pollution in urban environments and reduce the combined consumption of limited fossil fuel resources. Such vehicles fall into three main classes: electric vehicles (EV), hybrid electric vehicles (REV) and partly hybrid electric vehicles (also known as 42 volt vehicles).

Electric and electric vehicles can accumulators, in hybrid vehicles use many different types including

Partly hybrid batteries, lead-acid vehicles. electric current can use mainly lead-acid batteries in current luxury internal engines due to lower costs. Hybrid and partially hybrid electric vehicles are based on a combination of an internal combustion engine and a battery for supplying energy. Due to the increased on-board energy demand of cars (combustion cars), the capabilities of current 14-volt alternators are close to or exceed their limits. Thus, partially hybrid electric vehicles have been developed. These partially hybrid electric vehicles use a 36-volt battery and a 42-volt alternator. Partially hybrid electric vehicles have some advantages in

Compared to existing cars with internal combustion engines, including greater use of electrically generated energy, which leads to lower emissions.

[0004] Although significant progress has been made in developing new batteries and power grids for vehicles based at least partly on electricity, the batteries used in these vehicles are still a source of many problems.

[0005] All such batteries have different requirements on the battery in terms of the current consumed and supplied when the battery is being charged at various stages of the vehicle's operation. For example, a high discharge rate from the battery is necessary to enable acceleration or engine start in electric and hybrid electric vehicles, respectively. The fast battery charging speed is associated with regenerative braking.

[0006] In a situation in which lead-acid batteries are used, especially in hybrid and partially hybrid electric vehicles, the high rate of battery discharge and charging results in the formation of a lead sulfate layer on the negative surface of the plate, and the formation of hydrogen / oxygen on the plates, negative and positive. This is mainly due to the high demand for battery power. The partial charge (PSoC) states in which these batteries usually work is 20100% for electric vehicles, 40-60% for hybrid electric vehicles, and 70-90% for partially hybrid electric vehicles. This is a state of partial load with high load (HRPSoC).

EP 2 273 602 B1

When simulated work under HRPSoC, as in the work of a hybrid and partially hybrid electric vehicle, lead-acid batteries fail prematurely mainly due to the gradual accumulation of lead sulfate on negative plate surfaces. This is because lead sulfate cannot be efficiently converted back to spongy lead during charging due to regenerative braking or by the engine. Ultimately, this lead sulphate layer develops to such an extent that the effective surface area of ​​the plate decreases significantly and the plate can no longer provide the higher currents required by the vehicle. This significantly reduces the potential battery life.

[0007] In other technical fields, including mobile or cellular phone techniques, it would be beneficial to develop alternative types of batteries that offer increased total usage and operation time meeting the various energy requirements of the device.

[0008] Accordingly, there is a need for modified batteries, including lead-acid batteries, which have increased lifetime and / or improved overall performance compared to current batteries.

Summary of the Invention [0009] According to one aspect, there is provided a lead-acid battery comprising:

• at least one negative lead-based electrode;

• at least one positive lead dioxide electrode;

• at least one capacitor electrode, and

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• electrolyte in contact with the electrodes;

wherein the battery portion is formed by a lead-based negative electrode and a positive lead dioxide electrode; and the asymmetrical capacitor portion is formed by a capacitor electrode and one of the electrodes: a negative lead-based electrode or a positive lead dioxide electrode; and wherein all negative electrodes are connected to the negative rail, and all positive electrodes are connected to the positive rail, wherein the electrolyte is sulfuric acid.

[0010] According to this aspect, each of the capacitor electrodes may be separately a positive or negative electrode. [0011] In one embodiment, the capacitor electrode is a negative capacitor electrode. In this embodiment, the lead dioxide battery part and the asymmetrical condenser part of the lead-acid battery are connected in parallel into one common unit. As a result, the asymmetrical capacitor portion preferably draws or releases a charge during high current charging or discharging. This is because the asymmetrical capacitor part has a lower internal resistance than the battery part, and the first will absorb and release the load during fast charging (e.g. during regenerative braking) or during quick discharge (e.g. during acceleration of the vehicle and starting the engine). As a result, the asymmetrical capacitor part will share fast operation with the lead-acid battery part, which will ensure a much longer life for the lead-acid battery. This is all achieved without any control

Electronic or switching between the battery and capacitor parts.

[0012] According to one embodiment, the positive electrode is common to two parts and is sandwiched between a lead-based negative electrode and a negative capacitor electrode.

[0013] It should be understood that an inverse system can be used in which the lead-based negative electrode is a common electrode. A lead-based negative electrode will define an asymmetrical capacitor with a positive capacitor electrode.

[0014] Preferably, the lead-acid battery comprises an alternating series of positive and negative electrodes. Of the alternating electrodes, each can be a battery electrode, a capacitor electrode, or a combined battery / capacitor electrode. These types of electrodes will be described in detail below.

[0015] As an additional feature of the invention, it has been found that if there is a mismatch in the potential window or range of potentials of one of the electrodes, hydrogen gas evolution may occur. This is especially the case when the cell voltage is greater than the electrode potential range. The evolution of hydrogen gas is undesirable because it leads to premature battery failure at the electrode, where gassing occurs.

[0016] To avoid mismatching, according to another embodiment, at least one of the negative capacitor electrodes comprises a large surface area capacitor material, and one or more additives selected from oxides, hydroxides or sulfates of lead, zinc, cadmium, silver and bismuth. The extras are

Preferably added in the form of oxides. The additives are preferably lead and / or zinc additives, most preferably lead and / or zinc oxide.

[0017] Mismatch can also occur at the positive capacitor electrode. Thus, in accordance with one embodiment in which the battery comprises a positive capacitor electrode, the positive capacitor electrode includes:

capacitor material with a large surface area,

Pb2O3, antimony oxide, hydroxide or sulfate, and optionally one or more additives selected from iron and lead oxides, hydroxides and sulfates. [0018] According to an additional feature of the invention, new capacitor electrodes based on the above idea are also described. The new negative capacitor electrode contains a current collector and a pasty coating, the pasty coating containing a large surface area capacitor material, a binder and 5-40% by weight, based on the weight of the pasty coating, additive or mixture of additives selected from oxides, hydroxides or sulfates, zinc, cadmium, silver and bismuth, provided that the additive contains at least one lead or zinc oxide, hydroxide or sulfate.

[0019] The new positive capacitor electrode comprises a current collector and a paste-like coating, the paste-like coating containing a large surface area capacitor material, a binder and 10-40% by weight, based on the weight of the paste-like coating, of a mixture of additives including: Pb2O3, oxide, hydroxide or antimony sulfate, and

Optionally one or more iron and lead oxides, hydroxides or sulfates.

Brief description of the drawings [0020]

Figure 1 is a schematic side view of a lead-acid battery in accordance with one embodiment of the invention;

Figure 2 is a schematic top view of the lead-acid battery of figure 1;

Figure 3 is a graph representing the current profile of a single cycle test run on the battery of the embodiment of figures 1 and 2;

Figure 4 is a graph representing the duty cycles of the battery of figures 1 and 2 and the comparative battery;

Figure 5 is a schematic side view of a lead-acid battery in accordance with a second embodiment of the invention;

Figure 6 is a schematic side view of one of the negative electrodes of the lead-acid battery of figure

5;

Figure 7 is a graph representing the rate of hydrogen evolution from a negative capacitor electrode according to the fourth embodiment of the invention, compared to a standard carbon electrode and a standard lead-based negative electrode;

Figure 8 is a schematic side view representing the battery electrode system according to the third embodiment of the invention.

Detailed description of the invention

[0021] The present invention is described below in further detail with reference to preferred embodiments of the invention.

[0022] For the avoidance of doubt, except where the context requires otherwise due to a special expression or the necessary implication, the word "include" or include ", or variations such as" includes "or" includes "or" containing "or" including "applies in an inclusive sense, i.e. to indicate the presence of given features, but not to exclude the presence or addition of further features in various embodiments of the invention.

General features [0023] The term "lead-acid battery" is used in the broadest sense to include any unit containing one or more lead-acid battery cells.

[0024] The lead-acid batteries described contain at least one lead-based negative electrode or area, at least one lead-based positive electrode or area, and at least one negative electrode or area capacitor.

[0025] Each of these types of electrodes is described below, followed by the idea of ​​the electrode area.

Electrode structure [0026] The electrodes generally comprise a current collector (otherwise known as a grid or plate), with an active electrode material applied thereto. The active electrode material is most often applied as a paste to a current collector, and in this specification the term paste applies to all such containing active material

Compositions applied in any way to the current collector. The term "based" used in the context of electrodes is intended to refer to active electrode material. This term is used to avoid the suggestion that the electrode is made entirely of active material because it is not. The term is also intended to indicate that the active material of a given electrode may contain additives or materials other than the active material specifically mentioned.

Lead and lead dioxide electrodes.

[0027] Lead and lead dioxide electrodes may be of any system or type suitable for use in a lead-acid battery. Generally, such electrodes are in the form of a metal grid (usually made of lead or lead alloy) supporting the electrochemically active material (lead or lead dioxide) which is applied as a paste on the grid. The paste application operation is well known in the art. Although any suitable lead or lead dioxide known in the art may be used, it would be preferable to use the lead compositions disclosed in the co-pending application PCT / AU2003 / 001404 (claiming priority from Australian Patent Application AU 2002952234) published as WO 2004/038051. it should be noted that, prior to forming the battery, the active material may not be in active form (i.e. may not be in the form of metal, or in the form of dioxide) Thus, the terms include those other forms that convert to metallic lead or lead dioxide when the battery is formed.

Capacitor electrodes

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[0028] Capacitor electrodes similarly comprise a current collector and an active material coating. It is usually applied as a paste.

[0029] The term "capacitor" is used in the context of electrodes to describe electrodes that store energy due to the capacity of the double layer of the particle / solution interface between materials with a large surface area and an electrolyte solution.

[0030] There are two main classes of capacitors. One class is "double layer capacitors" (otherwise known as "asymmetrical capacitors") containing two such electrodes, one as positive and the other as negative. The second class are asymmetrical capacitors, which are also referred to as hybrid capacitors, "ultracapacitors" and "supercapacitors".

[0031] Asymmetrical capacitors comprise one electrode storing energy in the capacity of a double layer at the particle / solution interface, and a second electrode, i.e. a Faradejan or battery type electrode, which stores energy pseudo-capacitance. The prefixes 'ultra' and 'super' are sometimes used to generically describe asymmetrical capacitors, and sometimes to designate such a capacitor with great storage capacity. In this application, the prefix "ultra" is most commonly used in the first sense, but is sometimes used in the second sense, as the capacitance of the capacitor parts of the batteries of the present invention is preferably high. Asymmetrical capacitor portions preferably contain

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EP 2 273 602 B1 capacitor, ultra capacitor.

more preferably [0032]

Generally, as for lead and lead oxide electrodes, the capacitor electrode includes a metal grate (usually lead alloy) and a paste coating containing condenser material, usually with a binder. Carboxymethyl cellulose and neoprene are examples of suitable binders for paste compositions.

[0033] The capacitor electrode conveniently contains materials with a large surface area (or for high loads) suitable for use in materials are well known in capacitors. Such this area. Such materials for high-capacity capacitors include high surface area carbon, ruthenium oxide, silver oxide, cobalt oxide and conductive polymers.

Preferably, the negative capacitor electrode comprises a carbon material with a large surface area. Examples of carbon materials with a large surface area are activated carbon, soot, amorphous carbon, carbon nanoparticles, carbon nanotubes, carbon fibers and mixtures thereof.

[0034] Often mixtures of materials are used to achieve the right balance between surface area (and thus capacity) and conductivity. Currently, due to costs, activated carbon is the most suitable source. Some suitable activated carbon is coal with a specific surface area between 1000 and 2500 m²/ g, preferably 1000-2000 m²/ G. This material is conveniently used in combination with more conductive material such as carbon black. One of the appropriate carbon blacks has a specific surface area of ​​60-1000 m²/ G. One right

The mixture of these materials contains 5-20% carbon black, 40-80% activated carbon, 0-10% carbon fibers, and 5-25% residual binder. All measurements are by weight unless otherwise stated.

The content of additives in the capacitor electrodes [0035] As described above, it has been found that if there is a mismatch in the potential window or the operating range of one of the electrodes, hydrogen and / or oxygen evolution may occur. According to one embodiment, to suppress hydrogen gassing, the negative capacitor electrodes comprise an additive or additive mixture including lead, zinc, cadmium, silver and bismuth oxide, hydroxide or sulfate, or a mixture thereof. In general, it is preferred that the additive contains at least one lead or zinc oxide, hydroxide or sulfate. For convenience, the additive is conveniently one or more oxides selected from lead oxide, zinc oxide, cadmium oxide, silver oxide and bismuth oxide. Preferably, each of the negative capacitor electrodes contains an additive in addition to the large surface area capacitor material. Because of toxicity, cadmium compounds are not preferred, so the composition preferably contains a lead and / or zinc compound, and optionally a silver compound. For reasons of cost, silver oxide and bismuth oxide are usually avoided.

[0036] Regardless of the form in which the additive is added, when the conductor comes in contact with the electrolyte - sulfuric acid, the additive can react with the electrolyte and thus transform into another metal compound derived from the initial metal oxide, sulfate or hydroxide. References to oxides, sulphates and

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The hydroxides from the additives in question should be read as including the reaction products between the additives and the electrolyte. Similarly, if, during the state of charge or discharge of the battery, the additive transforms into another form in redox reactions, references to oxides, sulphates and hydroxides should be read as including the redox reaction products of those additives.

[0037] To suppress oxygen gassing, the positive capacitor electrodes preferably comprise: a large surface area capacitor material (as described above),

Pb2O3 ("red lead"), antimony oxide, hydroxide or sulfate, and optionally one or more additives selected from iron and lead oxides, hydroxides and sulfates. [0038] The antimony compound is beneficial in suppressing (oxygen) gassing on a positive electrode if it migrates to a negative one, it has a detrimental effect on hydrogen gassing on this electrode. In the absence of an antimony binding agent with a positive capacitor electrode, when the antimony compound comes into contact with the electrolyte, it can dissolve in the electrolyte and deposit on the negative electrode when current is applied. Red lead is used to bind or prevent the transfer of antimony to a negative electrode. Lead and iron compounds (i.e. oxides, sulfates or hydroxides) are also preferred in this electrode and can also be used in a mixture of additives.

[0039] In any case, the additive is used in an amount that avoids hydrogen and oxygen gassing. There is a capacitor. However, the capacitor electrodes,

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Condenser (more preferably, the electrodes of the Pb compound of Zn compound contain

1-20%), is generally the amount increasing the window of the negative and positive capacitor electrodes from typical ± 0.9V or ± 1.0V to at least ± 1.2V, and preferably at least ± 1.3V. In general, the total oxide content may be 5-40% by weight, based on the total composition of the active material (including high surface activity material, binder, and any other ingredient in the dried paste composition).

[0040] Preferably, the addition of a negative 1-40% by weight

1-20% by weight (more preferably 1-10%), 0-5% by weight of Cd and 0-5% by weight of Ag. Preferably, the whole is in the range of 5-40% by weight mentioned above. The use of ZnO alone gives good results, as does PbO alone or a mixture of PbO and ZnO.

[0041] Preferably, the addition of a positive capacitor electrode contains 0-30% by weight Pb (preferably 1-30% by weight) in the form of an oxide (any oxide), sulfate or hydroxide, 1-10% by weight Pb2O3, 0-2% by weight Fe ( preferably 1-2% by weight) in the form of an oxide, sulfate or hydroxide and 0.05 to 1% by weight Sb in the form of an oxide, sulfate or hydroxide. Preferably, Sb is added as the oxide. Preferably the total amount is in the range of 5-40% by weight mentioned above.

Other electrodes [0042] As described in further detail below, the battery may include electrodes of other types in addition to or instead of the electrodes described above. In particular, the battery may contain one or more

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Mixed capacitor-battery electrodes, such as a positive capacitor-battery electrode.

[0043] In a situation where the positive capacitor electrode (as described above) contains lead oxide, it is converted to lead dioxide when the battery is being charged. Thus, a capacitor electrode containing a lead source that is converted to lead dioxide during battery operation can be considered a capacitor-battery electrode having some features of a capacitor electrode and a battery electrode.

[0044] The incorporation of a material with a large surface area such as carbon into some positive electrodes can be carried out to meet the need to balance the positive to negative electrode surface area ratio. In the absence of positive capacitor electrodes, negative capacitor electrodes with a large surface area increase the larger total surface area of ​​the negative electrodes compared to the positive electrodes. When there is an imbalance in the surface area, electrodes with a lower surface area fail. By increasing the surface area of ​​positive electrodes, by introducing carbon with a large surface area into certain positive electrodes, the balance is improved. [0045] In the field of the consequences of the above, those skilled in this understanding understand that the battery may comprise an alternating series of positive and negative electrodes, with the electrolyte in contact with the electrodes, and a first conductor for direct connection of positive electrodes and a second conductor for direct connection of negative electrodes, where at least one pair of adjacent positive and negative electrode areas forms a capacitor

(By storing capacitive energy), and at least one pair of adjacent positive and negative electrode areas form a battery (by storing energy as electrochemical potential between two electrode pairs).

Areas [0046] The electrodes of the present invention may be composite electrodes (i.e., they may be composites of battery electrode materials and capacitor electrode materials). References to "lead-based", "lead-dioxide" and "capacitor" electrodes include areas of the electrode that have the indicated function, regardless of whether the single electrode has other areas of another type.

[0047] According to one embodiment of the invention, electrodes having regions of different types are intentionally used. According to this embodiment, the one or more negative electrodes have at least two areas, including a material area of ​​the battery electrode and a material area of ​​the capacitor electrode. As one example, an electrode having two areas includes an electrode current collector, which may be of the type described above, having one side coated with paste material from a battery electrode (such as lead) and the opposite side coated with paste material from a negative capacitor electrode. Alternatively, the battery-type electrode containing the battery electrode material on both sides may be coated on one side or on any other area with the capacitor electrode material.

Physical configuration

[0048] The electrodes may have any suitable shape, and thus may be in the form of a flat plate or in the form of a spirally wound plate to form prismatic or spirally wound cells. Flat plates are preferred for simplifying the design.

Electrolyte [0049] For lead-acid batteries, sulfuric acid electrolyte is used.

The electrolyte may be in liquid or gel form, for example.

Rails or conductors [0050] The lead-acid battery rail can be of any suitable construction, and can be made of any suitable conductive material known in the art. The term "connected to" when used in the context of busbars refers to electrical connection, although direct physical contact is preferred. If the battery does not have the configuration of a typical lead-acid battery with rails, any conductor that does not include external circuits for the battery can be used.

Other Battery Features [0051] Generally, the battery components are included in the battery housing with additional features specific to the type of battery being used. For example, a lead-acid battery may have an electrolyte-flooded construction or with valves. When the lead-acid battery is a lead-acid battery with valves, the battery may be of any suitable construction, and may for example contain a gel electrolyte. specific

The features of the battery unit corresponding to such constructions are well known in the art. [0052] The pressure that can be used in a lead-acid battery may be in the range of 5-20 kPa for electrolyte-flooded construction and 20-80 kPa for a lead-acid battery design with valves.

Spacers [0053] Generally, each of the positive and negative electrodes is separated from adjacent electrodes by porous spacers.

[0054] The spacers maintain a suitable separation distance between adjacent electrodes. Spacers sandwiched between directly adjacent lead-based negative electrodes and lead-based positive electrodes can be made from any suitable porous material commonly used in the field, such as porous polymeric material or absorbent glass microfiber ("AGM"). The separating distance (corresponding to the thickness of the spacer) is usually from 1-2.5 millimeters for these spacers. Suitable polymer materials useful for forming spacers between the positive and negative electrodes forming the battery part are polyethylene and AGM. The polyethylene spacers are conveniently between 1 and 1.5 millimeters thick, while the AGM spacers are between 1.2 and 2.5 millimeters respectively.

[0055] For spacers sandwiched between the positive electrode and the negative electrode of the capacitor, they are conveniently much thinner than the spacers of the battery portion of the lead-acid battery. Preferably, the spacers have a thickness between 0.01 and 0.1

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Millimeter, and most preferably between 0.03 and 0.07 millimeter. These spacers are conveniently made of a microporous polymeric material, such as microporous polypropylene. Other spacers are AGMs and the thickness of this type of spacers is from 0.1 to 1 millimeter, preferably from 0.1 to 0.5 millimeter.

Forming lead-acid batteries [0056] After assembling the appropriate components in the battery housing, the lead-acid battery generally needs to be formed. The forming operation is well known in the art. It should be understood that references to "lead-based" and "lead-dioxide-based" materials are used to refer to lead or lead dioxide alone, metal / metal dioxide containing materials, or materials converting to lead or lead dioxide, as the case may be, electrode.

[0057] As the language used above indicates, lead acid contains at least one of each type of electrode. The number of individual cells (created by the negative and positive plates) in a battery depends on the desired voltage of each battery. For a 36-volt battery suitable for use as a partially hybrid electric vehicle battery (which can be charged up to 42 volts), this includes the use of 18 cells.

on a given battery

Electrode system [0058] For best performance according to one embodiment, the positive and negative electrodes are interlaced such that each positive electrode has one

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EP 2 273 602 B1 lead-based negative electrode on one side, and one negative electrode capacitor on the opposite side. Accordingly, the system in one embodiment has alternating positive and negative electrodes, with negative electrodes being alternatively a lead-based electrode and a negative capacitor electrode. All negative electrodes (lead and carbon) are connected to the negative rail, and the positive electrodes are connected to the positive rail, so that each battery cell and ultracapacitor cell are connected in parallel in a regular lead-acid battery.

Operation [0059] As explained above, the ultracapacitor cell in the lead-acid battery system described has a lower internal resistance than the lead-acid battery cell, and thus will be the first to absorb during quick charging (for regenerative braking charge released or during quick discharge (accelerating the vehicle and engine start). As a result, the cell of the asymmetrical capacitor will share the rapid operation of the lead-acid battery cell will provide the lead-acid battery for a much longer operating time. More specifically, the formation of battery sulfate, which the electrodes of the cells take place during lead on usually high-current battery charging and discharging, is minimized because high-current charging and discharging generally dissolves in the asymmetrical capacitor.

[0060] Each battery cell of one embodiment of the invention provides a voltage of 2 volts. A lead-acid battery according to one embodiment suitable for use in a wide range of applications for electric vehicle batteries contains 8 negative electrodes and 9 positive electrodes, with 4 negative electrodes being lead-based negative electrodes and the remaining 4 are capacitor electrodes in the system alternating. Changes in this arrangement and the relative numbers of electrodes are also appropriate as long as there is a minimum of one each electrode.

EXAMPLES Example 1 [0061] A lead-acid battery according to one embodiment of the invention suitable for testing purposes was made in the system illustrated schematically in figures 1 and 2.

[0062] Two spongy lead (negative plate) electrodes (1), two positive lead dioxide electrodes (2) and one negative carbon electrode plate (3) with a high surface area are arranged in an alternating arrangement as illustrated in figure 1 in the case of the battery (4). The positive lead dioxide electrodes (2) and the negative lead electrodes (1) were 40 millimeters wide by 68 millimeters high by 3.3 millimeters thick. The carbon electrode (3) was 40 millimeters wide by 68 millimeters high by 1.4 millimeters thick. The battery electrodes had a standard configuration and composition for lead-acid batteries, and were formed as described

In the detailed description above. The lead electrode forming techniques used in this example are further described in our pending application PCT / AU2003 / 001404 published as WO2004 / 038051. In short, the composition of the paste for the negative lead electrode contained lead oxide (1 kg), fiber 0.6 g, BaSO4 4.93 g, carbon black 0.26 g, H2SO4 (relative density 1,400) 57 cm³, water 110 cm³, acid to oxide ratio 4% and paste density 4.7 g / cm³. The composition of the paste for a positive lead dioxide electrode contained 1 kg lead oxide,₃ fiber 0.3 g, H2SO4 (relative density 1,400) 57 cm³, water ₃

130 cm³, acid to oxide ratio 4% and paste density 4.5 g / cm³. Lead oxide was converted into lead and lead dioxide by the molding techniques described in our pending application.

[0063] The capacitor electrode (3) was made of 20% ₂ soot with a specific surface area of ​​60 m² g (Denki Kagaku, Japan), 7.5% by weight carboxymethylcellulose, 7.5% by weight neoprene, and 65% by weight activated carbon with a specific surface area of ​​2 -1

2000 m² g^-1 (Kurarekemikaru Co. Ltd. Japan).

[0064] The spacers (5, 6) were placed between adjacent electrodes. Spacers (5) of 2 mm thick absorbent glass (AGM) microfibers were placed between lead dioxide (2) and lead (1) electrodes, and microporous polypropylene spacers (6) 0.05 mm thick were inserted between the positive electrodes (2 ) and carbon electrode (3).

[0065] The battery housing (4) was filled with sulfuric acid solution (7). Positive electrodes were connected to the positive rail (8), and negative electrodes were connected to the negative

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EP 2 273 602 B1 by rail (9). As indicated below, for comparison purposes, for the simulation of a battery that does not contain an ultracapacitor cell, the negative capacitor plate could be disconnected from the negative bus.

[0066] For testing purposes, a charging and discharging profile has been developed to simulate typical charging and discharging requirements on a 42-volt battery for a partially hybrid electric vehicle, typically used in applications for a partially hybrid electric vehicle. The profile has a short duration (2.35 minutes) and is composed of several current stages simulating the demand for battery power during vehicle operation. They are, in order:

(a ) an idle stop section involving a 2 A discharge over 60 seconds;

(b) 17.5 A high current discharge, lasting 0.5 seconds, simulating starting;

(c) discharge of the assistance power of 8.5 A for 0.5 seconds;

(d) a maximum of 14 volts / 2 A, a 70 second engine charging section simulating battery charging during standard driving conditions;

(e) a 5-second rest period; and (f) a maximum 14-volt / 2A regenerative charge period (braking for 5 seconds.

[0067] The critical stage is the start-up period during which the cell must provide 17.5 A for 0.5 seconds.

correlating with regenerative)

Testing

[0068] To test the battery life of the example, two identical batteries were prepared, and one was then modified to disconnect the negative carbon capacitor electrode from the negative rail to match the equivalent battery without the integral features of the ultracapacitor, and hereinafter referred to as "Comparative battery".

[0069] Each battery was subjected to repeated cycles of the profile illustrated in figure 3 and described above. A 1.6 volt cut-off voltage was set, which is the usual cut-off voltage value for batteries in the field of the invention, and the batteries were subjected to repeated cycles throughout the charging cycle until the lowest voltage reached the cut-off value during discharge.

[0070] The test results are illustrated in figure 4. In this figure, line 10 shows the internal battery resistance profile, line 11 shows the internal battery resistance profile of example 1, line 12 shows the minimum discharge voltage profile of the comparative battery and line 13 shows the minimum voltage profile battery discharge from example 1.

[0071] During the cycles, the following observations were made:

(i) the maximum charging voltages of the reference battery and the battery of Example 1 are maintained at 2.35 volts, as shown on line 14.

(ii) the internal resistances of both batteries increase in cycles. However, the internal resistance of the comparative battery increases faster than the battery of Example 1, for example, from 19 to 25 mΩ for the battery

Comparative and from 18 to 25 mΩ for the battery of example 1.

(iii) The minimum discharge voltages of the comparative battery and battery of Example 1 decrease in cycles, but the decrease rate is higher for the comparative battery.

[0072] The comparative battery performs about 2150 cycles, while the battery of Example 1 performs 8940 cycles before the minimum discharge voltages of each battery reach a cut-off value of 1.6 volts (represented by line 15). Thus, the cyclic battery performance of Example 1 is at least four times better than the comparative battery.

Example 2 [0073] A variant of the battery of example 1 is illustrated in figures 5 and 6. For ease of comparison, the same numbers are used to refer to the common components of two batteries.

[0074] The embodiment of this example includes three positive lead dioxide electrode plates (2) and two composite negative electrodes (16). The composite negative electrodes comprise a current collector or grille (17) with a lead-containing paste composition described above applied to one area (side) (18) and a paste containing a large surface area carbon electrode material used on the opposite side (19). The electrode formation is carried out in a manner known in the art. In a variation of this simpler embodiment, the lead-based negative electrode is made from lead applied as a paste

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Conventional techniques of dipping a portion of the main body into the lead paste material and then forming, and then the condenser material is applied as a paste to an area or areas of this lead-based negative electrode, for example to one side thereof. The positive (2) and negative composite electrodes (16) are arranged in an alternating arrangement, as illustrated in figure 5 in the case of the battery (4).

[0075] The positive lead dioxide electrodes (2) and the negative composite electrodes (16) of the embodiment illustrated in figure 5 are 40 millimeters wide by 68 millimeters high by 3.3 millimeters thick. The carbon electrode area (19) of the negative electrode takes 1.4 millimeters of thickness of the negative electrode.

[0076] The spacers (5, 6) are arranged between adjacent electrodes. The 2 mm thick microfibers (AGM) spacers (5) are placed between the lead dioxide electrodes (2) and the lead side (18) of the negative electrode, and the microporous polypropylene spacers (6) with a thickness of 0.05 millimeters are inserted between the positive the electrode (2) and the carbon side of the negative electrode (19).

[0077] The battery housing (4) is filled with sulfuric acid solution (7). The positive electrodes are connected to the positive rail (8) and the negative electrodes are connected to the negative rail (9).

Example 3 [0078] Further tests of the battery of example 1 showed that an improvement in the electrolyte drying state could be achieved by adjusting the rate of hydrogen evolution from the carbon electrode (3) when charging the battery so that it is

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EP 2 273 602 B1 similar to that for the negative lead electrode (1). This was achieved by replacing the carbon electrode of example 1 with a modified carbon electrode (103) with 2.5% by weight PbO and 2.5% by weight ZnO, 65% by weight activated carbon, 20% by weight carbon black and binder (10% by weight) in the paste composition .

[0079] The hydrogen evolution rates for this electrode were tested and compared with the electrode used in Example 1, as well as the hydrogen evolution rates of the negative lead electrode of Example 1. The results are shown in Figure 7, where curve 20 represents the rate of hydrogen evolution from the carbon electrode, curve 21 represents the rate of hydrogen evolution from a negative lead-acid plate, and curve 22 represents the rate of hydrogen evolution from a carbon electrode with additives. Higher current density levels recorded for a carbon electrode without the addition of oxide increases significantly at potentials falling below -1.2 V, and even more so at -1.3 V. By closer matching of the rate of hydrogen evolution from two electrodes, the battery can be operated at higher potentials without prior damage due to electrolyte drying.

[0080] The addition of CdO oxide will have a similar effect as ZnO and PbO, but due to toxicity it was not used in the tests. AgO has a similar effect, but is a costly addition and not as effective alone. In other tests, ZnO and PbO levels ranged from 1-10% and 1-20%, respectively, and AgO between 1-5%. Other oxides mentioned in the detailed description above have a similar effect as AgO.

55P36419PL00

EP 2 273 602 B1 is illustrated to understand that

Example 4 [0081] A further variation of the battery of Example 1 is illustrated in Figure 8. For ease of comparison, the same numbers are used to refer to common components of two batteries. Also, for simplicity, only the battery electrodes. The battery should also contain spacers, housing, electrolyte, busbars, terminals and other battery components common in this field.

[0082] The battery of this example contains an alternating series of positive and negative electrodes. The electrodes are, from left to right, the positive electrode (2) of the lead dioxide battery, the negative electrode (3) of the lead-based battery, the second positive electrode (2) of the lead-dioxide battery, the carbon with the addition of a negative capacitor electrode of the type described in example 3 (103), a positive capacitor-battery electrode as described below (23), a second carbon with the addition of a negative capacitor electrode of the type described in Example 3 (103), a second lead based negative electrode (3) battery and a third positive electrode (2) of lead dioxide battery. Each positive and negative electrode, respectively, positive conductor are connected to the conductor, and the battery.

[0083] The electrode (23) with negative battery-capacitor terminals contains a positive metal current collector, with a mixture of activated carbon (60% by weight), carbon black (20% by weight) and 10% by weight of lead oxide applied as a paste. The paste composition is formed from 10% by weight [5% by weight carboxymethyl cellulose and 5% by weight neoprene] agent

Binding and sintered on a current collector. The electrode has a thickness of about 0.8 mm. Gassing tests show that the inclusion of SbO and red lead in this positive capacitor electrode has a beneficial effect on gassing, and therefore these additives can also be included in the positive capacitor electrode.

[0084] The battery of this example may include further alternating positive and negative electrodes of any type. In general, it is desirable to ensure that there is a certain level of surface area matching and gassing intensity of the sum of positive and negative electrodes, and enable the required number of positive and negative electrodes to produce a battery with the desired voltage.

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55P36419PL00

EP 2 273 602 B1