Fuel cell and method for making such a cell with large active surface and reduced volume
Abstract
Method of manufacturing a fuel cell, said battery comprising a set of elementary cells electrically connected to each other, each elementary cell comprising at least three layers, that is to say a membrane layer placed between a first electrode layer and a second electrode layer , said procedure successively comprising the following steps: - a stage of realization of a plurality of holes (1, 10) in at least two supports (9), each hole leading out of both sides of two opposite faces (9a, 9b) of each support, by means of a first section (1a) of hole and a second section (1b) of hole and each hole having a lateral surface (1c), - a stage of realization of elementary cells on the lateral surface (1c) of each of said holes, - a stage of realization, in at least one of said opposite faces of each support, of a network of electrical connections (11, 12), and of a reagent distribution network, said networks joining the elementary cells between them, constituting the assembly formed by a support, by elementary cells and by said networks a base module (9 ''), - an assembly stage of at least two base modules (9 ''), so that the elementary cells of each base module are placed opposite each other with the elementary cells of the adjacent base module (s); said method being characterized in that, during the stage of realization of the plurality of holes, each hole is made such that at least one of said first or second orifice section (1a, 1b) of each hole has a surface less than the surface of at least one section of said hole taken in a plane parallel to said opposite faces and because, for each hole, The first or second hole section has a surface less than the surface of the other hole section.

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Projected expiry passed 15 November 2022, 3.9 years ago.
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20 claims: 5 independent, 15 dependent
- 1ES 2 289 179 T3 REIVINDICACIONES 1. Procedimiento de fabricación de una pila de combustible, comprendiendo dicha pila un conjunto de células elementales conectadas eléctricamente entre ellas, comprendiendo cada célula elemental al menos tres capas, es decir una capa de membrana colocada entre una primera capa de electrodo y una segunda capa de electrodo, comprendiendo dicho procedimiento sucesivamente las siguientes etapas:- una etapa de realización de una pluralidad de agujeros (1, 10) en al menos dos soportes (9), desembocando cada agujero, de una y otra parte de dos caras opuestas (9a, 9b) de cada soporte, mediante una primera sección (1a) de orificio y una segunda sección (1b) de orificio y presentando cada agujero un superficie lateral (1c), - una etapa de realización de células elementales en la superficie lateral (1c) de cada uno de dichos agujeros, - una etapa de realización, en al menos una de dichas caras opuestas de cada soporte, de una red de conexiones eléctricas (11, 12), y de una red de distribución de reactivos, uniendo dichas redes las células elementales entre ellas, constituyendo el conjunto formado por un soporte, por unas células elementales y por dichas redes un módulo (9') de base, - una etapa de ensamblaje de al menos dos módulos (9') de base, de manera que las células elementales de cada módulo de base sean colocadas enfrente con las células elementales del (de los) módulo(s) de base adyacente(s);estando caracterizado dicho procedimiento porque, durante la etapa de realización de la pluralidad de agujeros, cada agujero está realizado de tal manera que al menos una de dichas primera o segunda sección (1a, 1b) de orificio de cada agujero presenta una superficie inferior a la superficie de al menos una sección de dicho agujero tomada en un plano paralelo a dichas caras opuestas y porque, para cada agujero, la primera o segunda sección de orificio presenta una superficie inferior a la superficie de la otra sección de orificio.
- 2Procedimiento de fabricación de una pila de combustible según la reivindicación 1, caracterizado porque los agujeros son casi troncocónicos.
- 3Procedimiento de fabricación de una pila de combustible según la reivindicación 1, caracterizado porque los agujeros tienen casi una forma de pirámide truncada.
- 4Procedimiento de fabricación de una pila de combustible, según una cualquiera de las reivindicaciones 1 a 3, caracterizado porque cada agujero practicado en cada soporte presenta una primera sección de orificio y una segunda sección de orificio de superficies inferiores a la superficie lateral de dicho agujero.
- 5Procedimiento de fabricación de una pila de combustible, según una cualquiera de las reivindicaciones 1 a 4, caracterizado porque los agujeros, realizados en cada soporte, son efectuados por grabado.
- 6Procedimiento de fabricación de una pila de combustible, según la reivindicación 1 a 4 caracterizado porque los agujeros, realizados en cada soporte, son efectuados por ablación láser.
- 7Procedimiento de fabricación de una pila de combustible, según una cualquiera de las reivindicaciones precedentes, caracterizado porque el soporte está constituido por un material elegido en un grupo constituido por el silicio, tal como el silicio poroso, el grafito, las cerámicas, los polímeros.
- 8Procedimiento de fabricación de una pila de combustible según una cualquiera de las reivindicaciones precedentes, caracterizado porque la realización de las células elementales se efectúa por depósito sucesivo, en la superficie lateral de cada uno de dichos agujeros, de al menos tres capas, para constituir la primera capa de electrodo, la capa de membrana, la segunda capa de electrodo.
- 9Procedimiento de fabricación de una pila de combustible según la reivindicación 8, caracterizado porque la realización de las células elementales comprende además el depósito de colectores de corriente al nivel de cada capa de electrodo.
- 10Procedimiento de fabricación de una pila de combustible, según una cualquiera de las reivindicaciones 1 a 9, caracterizado porque el ensamblaje de dos módulos de base, cuando este ensamblaje se coloca enfrente de dos caras carentes de las redes definidas en la reivindicación 1, comprende sucesivamente las siguientes etapas:- una etapa de colocación, en al menos una de dichas caras carentes de redes, de una capa (13) de unión;y - una etapa de solidarización de los módulos de base, al nivel de dichas caras.
- 11Procedimiento de fabricación de una pila de combustible según una cualquiera de las reivindicaciones 1 a 9, caracterizado porque el ensamblaje de al menos dos módulos de bases, que se colocan enfrente de las caras, de las ES 2 289 179 T3 cuales al menos una está provista de una red de conexiones eléctricas y/o de distribución de los reactivos, comprende sucesivamente las siguientes etapas:- una etapa de camuflaje de la o las caras provistas de la o de las redes por una capa estanca y aislante;- una etapa de alisado de la o de las caras provistas de la o de dichas redes;- una etapa de colocación de una capa de unión en al menos una de las caras que hay que ensamblar;- una etapa de solidarización de dichas caras que hay que ensamblar de dichos módulos de base.
- 12Procedimiento de fabricación según la reivindicación 10 u 11, caracterizado porque la capa (13) de unión es una capa de constitución idéntica a la capa de membrana o una capa de un material elegido en el grupo constituido por el óxido de silicio o el nitruro de silicio.
- 13Procedimiento de fabricación de una pila de combustible según la reivindicación 10 u 11, caracterizado porque la capa de unión corresponde a un adhesivo elegido entre los epóxidos, las poliimidas, las siliconas, los polímeros acrílicos.
- 14Procedimiento de fabricación de una pila de combustible según una cualquiera de las reivindicaciones 10 a 13, caracterizado porque la etapa de solidarización se efectúa por apriete.
- 15Procedimiento de fabricación de una pila de combustible según una cualquiera de las reivindicaciones 10 a 13, caracterizado porque la etapa de solidarización se efectúa por adhesión molecular.
- 16Procedimiento de fabricación de una pila de combustible según una cualquiera de las reivindicaciones 10 a 13, caracterizado porque la etapa de solidarización se efectúa por encolado.
- 17Procedimiento de fabricación de una pila de combustible según la reivindicación 11, caracterizado porque la etapa de camuflaje, la etapa de alisado, la etapa de colocación de la capa de unión se efectúan simultáneamente por colocación de una capa única.
- 18Procedimiento de fabricación de una pila de combustible según la reivindicación 17, caracterizado porque la capa única es de constitución idéntica a la capa de membrana.
- 19Procedimiento de fabricación de una pila de combustible según la reivindicación 17, caracterizado porque la capa única es de un material elegido en el grupo constituido por el óxido de silicio y el nitruro de silicio.
- 20Pila de combustible que comprende:- al menos dos soportes (9) que comprenden una pluralidad de agujeros (1, 10), desembocando cada agujero de una y otra parte de dos caras opuestas (9a, 9b) de cada soporte, mediante una primera sección (1a) de orificio y un segunda sección (1b) de orificio y presentando cada agujero una superficie lateral (1c), - unas células elementales realizadas en la superficie lateral (1c) de cada uno de dichos agujeros, - en al menos una de dichas caras opuestas de cada soporte, una red de conexiones eléctricas (11, 12) y una red de distribución de los reactivos, uniendo dichas redes las células elementales entre ellas, constituyendo el conjunto formado por un soporte, por unas células elementales y por dichas redes un módulo de base, estando ensamblados al menos dos módulos de base de manera que las células elementales de cada módulo de base sean colocadas enfrente con las células elementales del (de los) módulo(s) de base adyacente(s);caracterizada porque cada agujero es tal que al menos una de dichas primera o segunda sección (1a, 1b) de orificio de cada agujero presenta una superficie inferior a la superficie de al menos una sección de dicho agujero tomada en un plano paralelo a dichas caras opuestas y porque, para cada agujero, la primera o segunda sección de orificio presenta una superficie inferior a la superficie de la otra sección de orificio.
Independent claims20
139 paragraphs in 6 sections, as filed
IS 2 289 179 T3
DESCRIPTION
Fuel cell and manufacturing process of such cells with a large active surface and a small volume.
Technical field
The present invention relates to a method for manufacturing a fuel cell with a large active surface and a small volume.
Therefore, the invention relates to the field of fuel cells, and more particularly to fuel cells having a solid polymer membrane as electrolyte, such as PEMFC (Protons Exchange Membrane Fuel Cell) and DMFC (Direct Methanol Fuel Cell).
Fuel cells of the solid polymer electrolyte type find their applications, particularly in land, space, maritime transport and, more particularly, in land vehicles, which are currently the subject of numerous development programs, with in order to find alternatives to the use of batteries in electric vehicles.
Prior state of the art
Generally, fuel cells are made up of a stack of elementary cells. Each of these cells comprises an anode and a cathode positioned on both sides of an electrolyte. At the anode level, oxidation of fuel occurs, such as hydrogen H<sub>2</sub>, for hydrogen cells, thus producing protons and electrons. The electrons go to the external electrical circuit, while the protons go towards the cathode, through the electrolyte, which is presented, generally in the form of an ionic conductive membrane. At the cathode level, oxidation of the oxidizer takes place, such as oxygen in the air, accompanied, in the case of hydrogen cells, by the production of water that results from the recombination of the ions produced by the reduction and of the protons.
The power densities obtained at the level of an elementary cell are very low and far insufficient to allow the operation of electrical equipment. Therefore, it is essential to assemble a significant number of these elementary cells, in order to access a significant power. Generally, the assembly is carried out by a stacking of elementary cells, the separation between the cells being carried out by means of watertight plates, called bipolar plates.
In the field of fuel cells, numerous configurations have already been proposed in the prior art.
Thus, fuel cells of medium power, that is, from 10 to 50 kW per cell, are generally manufactured by the "filter-press" association of bipolar graphite or stainless steel plates and the electrodomembrane-electrode assemblies obtained by pressing two tissue electrodes and a proton conducting NAFION® membrane.
Low-power fuel cells, that is to say 0.5 to 50 W per cell, called micro-fuel cells, require the development of architectures and procedures, often derived from microelectronics technologies. The difficulty lies in the assembly of the microelectrode with the thin film of proton conductive material. Additionally, the microelectrode must have a high electronic conductivity, a strong permeability to gas, particularly hydrogen, in the case of a PEMFC architecture, for hydrogen / air cells, a strong permeability to gas and methanol in the case of an architecture DMFC for methanol / air cells, an ability to be formed in the form of a thin layer on a small surface, a good thermomechanical resistance. The microelectrode must also have a surface suitable for depositing a catalyst in dispersed form.
In the literature, architectures based on porous silicon are distinguished in which a catalyst and then a Nafion membrane are deposited successively.<sup>®</sup> to form the electrode-membrane assembly. However, the performances of such a device are limited by the poor cohesion of the different layers, thus creating a strong interface resistance, and by a very low dispersion of the catalyst, the latter being little divided, in order to obtain a strongly deposition. electronic driver.
Different laboratories have developed technologies on non-porous silicon. A team from the Lawrence Livermore National Laboratory has thus developed a micro-fuel cell by first depositing a thin metallic layer of nickel that acts as an electronic collector on a silicon substrate. The catalyst and then the proton conductor are then deposited on the nickel. The nickel is then pierced by chemical etching to bring the catalyst and the reducing agent into contact, namely hydrogen or methanol according to the fuel cell system considered. This technique has a number of drawbacks, related in particular to the properties of nickel. Indeed, nickel is sensitive to corrosion phenomena caused by the strongly acidic character of the proton conductor. The catalyst is further dispersed weakly at the level of the perforated nickel layer, which has a poor ability to cause a homogeneous dispersion of the
ES 2 289 179 T3 reducing agent in the catalyst. Finally, this technology generates a low probability of the presence of triple points.
Patent application WO 97/11503 [1] and American patent US 5759712 [2] describe a fuel cell architecture based on the use of a micropore impregnated with a proton conductive material as the central element of a micro fuel cell system. . The different materials necessary in the formation of a fuel cell are then deposited on both sides of this substrate by classical vacuum deposition techniques. This invention has two main drawbacks, which are, on the one hand, the brittleness of the polymer substrate, especially when it is treated by aggressive vacuum deposition techniques, and, on the other hand, poor electrochemical performances, particularly related to the lack of active surface. and likewise, with the fragility of the catalyst deposit deposited directly on the proton exchange membranes.
The set of these architectures exposed has the particularity of being all smooth and does not, in fact, make it possible to obtain an electrode surface high enough to supply power to portable electronic devices.
To this end, various non-smooth geometries are proposed in the prior art.
US patents 6080501 [3], 6007932 [4] and 6001500 [5] describe a miniature fuel cell cylindrical architecture. This architecture is based on the winding of an electrode-membrane-electrode assembly conventionally used in smooth geometry around a metallic foam mandrel. However, the performances of such an assembly are mainly limited for two reasons:
- the electrode-membrane-electrode assembly, initially smooth, is not adapted to a cylindrical geometry, which makes it almost impossible to reestablish the anode-anode, cathode-cathode and membrane-membrane contacts after winding of the electrode-membrane assembly- smooth electrode;
- the current collectors are not in intimate contact with the anode and the cathode, thus generating too high interface resistances.
Another American team has developed a similar miniature tubular fuel cell concept. An electrode-membrane-electrode assembly is wound to form a cylinder. This is then integrated into a metal "cylinder holder" device that makes it possible to ensure the collection of the electric current. However, this type of architecture is not adapted to portable electronic devices, mainly due to the obstruction generated by the use of the "cylinder holder" system.
Patent JP 63138667 [6] presents a method for making a non-smooth cell structure, said process consisting of depositing a cell film on the internal surface of a part of the holes in a lattice support. The possibility of assembling several of these supports is also described.
However, this device, obtained by the described procedure, has the following drawbacks:
- from the fact of the configuration of the holes, more precisely from the fact that the holes have a parallelepiped shape of very little height, it is difficult to make a regular stack film deposit on the internal surface of said holes;
- due to the geometry and the arrangement of the holes in this document, it is necessary to dedicate a part of the holes of the lattice support to the transport of the reagents feeding the stack, which generates a loss of surface to deposit the films of battery and, consequently, a loss of power of said battery caused by this configuration.
Therefore, there is a real need for a fuel cell manufacturing process, which makes it possible to obtain cells that have a total volume as small as possible while preserving a high active electrode surface, and allowing the realization of a network of electrical connections. and distribution of reagents.
Furthermore, there is a need for this type of cell, which can develop electrical powers compatible with the use of said cells in the field, particularly in land transport.
Presentation of the invention
The object of the present invention is, therefore, to propose a method of manufacturing a fuel cell, adapted to everyday equipment, which responds, among other things, to the need mentioned above, and which does not present the drawbacks, the disadvantages, shortcomings and limitations of the prior art, and that it particularly makes it possible to produce a stack having an active surface much higher than its occupation surface on the ground. Additionally, the object of the present invention is to propose a method of making a fuel cell, which allows obtaining a high power cell while reserving an important space for the realization of an electrical connection network and connection of the reagents of said pile.
IS 2 289 179 T3
Finally, the object of the present invention is to provide a fuel cell that has a reduced volume, presenting a large active surface.
This object and other objects are achieved, according to the invention, by a method of manufacturing a fuel cell, said cell comprising a set of elementary cells electrically connected between them, each elementary cell comprising at least three layers, that is to say a layer membrane placed between a first electrode layer and a second electrode layer, said procedure successively comprising the following steps:
- a stage of making a plurality of holes in at least two supports, each hole opening on either side of two opposite faces of each support, through a first hole section and a second hole section and each hole presenting one lateral surface,
- a stage of making elementary cells on the lateral surface of each of said holes,
- a stage of realization, on at least one of said opposite faces of each support, of a network of electrical connections and of a reagent distribution network, said networks joining the elementary cells together, constituting the set formed by a support, by the elementary cells and by said networks a base module,
- a stage of assembling at least two base modules, so that the elementary cells of each base module are placed opposite the elementary cells of the adjacent base module (s);
said method being characterized in that, during the stage of making the plurality of holes, each hole is made in such a way that at least one of said first and / or second hole section presents a surface lower than the surface of at least one section of said hole taken in a plane parallel to said opposite faces and because, for each hole, the first or second hole section has a surface less than the surface of the other hole section.
It is specified that, according to the invention, the terminology "base module" refers to the assembly constituted by a support, in which elementary cells of battery are made, said cells being electrically connected to each other through networks of electrical connections and fed by reagent distribution networks, said networks being made at the level of at least one of the faces of the support, in which the holes are made.
It is specified that, according to the invention, the lateral surface designates the surface of the walls that delimit the hole.
It is specified that, according to the invention, the reagent distribution network designates the network, which will allow the supply of the electrodes with oxidant or reducing agent.
It is specified that, when it refers to a hole section taken in a plane parallel to the opposite faces of the support, it refers to all the sections except the hole sections mentioned above.
It is specified that, by support, it is preferably meant a support of almost parallelepiped shape.
It is specified that by active surface, it is understood, in what precedes and in what follows, the surface occupied by the electrodes, which are the seat of the electrochemical reactions of the cell.
Advantageously, holes in accordance with the present invention can be holes that are almost frustoconical in shape, or almost in the shape of a truncated pyramid.
The result of making holes with such a geometry has the following advantages:
- in relation to holes that have walls perpendicular to the support, as is the case in the realization of the Japanese document mentioned above, the fact of making holes that have a profile of holes of walls almost inclined in relation to the vertical, contributes to facilitate the deposit of the layers necessary in the constitution of elementary cells;
- in relation to holes that have walls perpendicular to the support, the fact of making holes that have a lower hole section surface in relation to the surface of the other hole section makes it possible to obtain a gain in space at the level of the faces where said holes are made, particularly at the level of the face presenting the hole sections of smaller surfaces; This site gain can be dedicated to the realization of the electrical connection network and the reagent distribution network, even in the creation of additional holes, in order to increase the active surface of the cell;
- in relation to holes that have walls perpendicular to the support, the lateral surface (or internal surface of the hole) may be more important, thus causing an increase in the active surface, insofar as the lateral surface serves as the basis for the realization of elemental cells.
IS 2 289 179 T3
It is specified that when it refers before, by way of comparison, to holes that have walls perpendicular to the support, these holes with perpendicular walls have a section identical to the first or second hole section mentioned above.
Additionally, the advantageous character of this invention resides in the fact of assembling two or more base modules in order to further increase the active surface of the resulting stack.
Thus, the interest of the present invention is to be able, in this way, to multiply the lateral surface of the holes, arranging them facing each other, by assembling at least two base modules.
Thus, thanks to this method according to the invention, it is possible to access fuel cells with a reduced footprint on the ground, presenting a high active surface, insofar as the active surfaces of the cell are in the core of the cell. constituent material of the support.
Additionally, the fact of making, according to the invention, systems that come from the assembly of several modules, in addition to the particular geometry of certain holes, has the important advantage of facilitating the production of the active layers on the walls of said holes.
Indeed, if a single-module pile architecture is considered, the slope of the walls, for example, for holes with conical volume, would be given by the geometry, particularly the thickness of the support, and the hole section surfaces. of the holes. In such a system, it would be necessary to develop steep walls to gain active surface. On the contrary, the system that comes from the assembly of several modules, such as that envisaged by the method according to the invention, can be constituted by modules whose height is smaller (than if a single module is used) and consequently, the walls Internal holes may have a less rigid profile. For this reason, it is easier, from this system, to carry out the deposit of layers, in order to constitute the elementary cells.
According to the invention, the holes, made in each support, can be made by engraving, or even by laser ablation.
The support can be constituted, according to the invention, by a material chosen from a group consisting of silicon, such as porous silicon, graphite, ceramics, polymers.
For example, the ceramics can be made of titanium or aluminum oxide and the polymers of Teflon®, Peek® or polysulfones.
Preferably, each hole made in each support has a first hole section and a second hole section with surfaces lower than the lateral surface of said hole, which has the advantage of dedicating a wide surface of the faces of the support to the realization of the electrical connection networks and the reagent distribution networks.
The realization of elementary cells, at the level of the holes made in each support, according to the invention is carried out by successive deposition on the lateral surface of each of said holes of at least three layers, to constitute the first electrode layer, the layer membrane and the second electrode layer.
This phase of implementation may also comprise the deposition of current collectors at the level of each electrode layer.
According to the invention, the assembly of two base modules, when this assembly places two faces lacking networks opposite each other (namely the electrical connection network and the reagent distribution network), can successively comprise the following stages:
- a step of placing, on at least one of said faces devoid of said network (s), of a bonding layer; Y
- a stage of solidarity of the base modules, at the level of said faces.
According to the invention, the assembly of at least two base modules, placing faces opposite each other, of which at least one is provided with a network of electrical connections and / or a reagent distribution network, may successively comprise the following stages:
- a stage of camouflage of the face or faces provided with said or said nets by a watertight and insulating layer;
- a step of smoothing the face or faces provided with said or said nets;
- a step of placing a tie layer on at least one of the faces to be assembled;
- a stage of integrating said faces to be assembled from said base modules.
IS 2 289 179 T3
Preferably, the tie layer is identical in constitution to the membrane layer.
This particularly has the advantage of being able to place, in a single stage, the membranes on the walls of the holes and the bonding layer on the surface.
According to a variant embodiment of the invention, the bonding layer can also be an adhesive other than the membrane layer, chosen from a group consisting of epoxides, polyimides, silicones and acrylic polymers.
According to another variant of the invention, the tie layer is made of a material chosen from silicon oxide and silicon nitride.
Once the bonding layer is in place, the two base modules can be fastened together, according to the invention, by clamping.
According to another embodiment of the invention, the joining of two base modules can be done by gluing.
Finally, the solidarity can be done by molecular adhesion.
Preferably, the step of camouflage, smoothing, gluing and positioning of the tie layer are carried out simultaneously by placing a single layer.
According to a particularly advantageous embodiment of the invention, the single layer is a layer of constitution identical to the membrane layer.
According to a variant, the single layer is a bonding layer of a material chosen from silicon oxide and silicon nitride.
Another object of the present invention is to propose a fuel cell capable of being obtained by the procedure described above.
Brief description of the drawings
The invention will now be described in more detail with reference to the accompanying drawings in which:
- Figure 1 represents a sectional view of a hole with geometry in accordance with the present invention, on the side surface of which an elemental cell of stack has been made by the method of the invention.
- Figure 2 represents a gentle perspective view, which reveals an assembly of two base modules (said assembly of two base modules being called "cavity level" according to the terminology of the invention).
- Figure 3 represents a sectional view representing an assembly resulting from the linking of two levels of cavities, said assembly being obtained by a method according to the invention.
- Figure 4 represents different assembly modes of 4 base modules.
Detailed statement of the invention
The method of manufacturing a fuel cell, according to the invention, successively comprises a step of making a plurality of holes in at least two supports, followed by a step of making elementary cells at the level of each of the holes, a stage of making, on at least one of the faces of each support, a network of cathode connections, a network of anode connections and a distribution network for the reagents, after which the assembly obtained is a base module, an assembly stage of at least two base modules, said holes being made in such a way that at least one of said first and / or second hole section of each hole has a surface lower than the surface of at least one section of said hole taken in a plane parallel to said opposite faces and wherein, for each hole, the first or second hole section has a surface less than the surface of the other hole section.
The step of producing the plurality of holes, at the level of each support, can be carried out according to any known method, for example, by means of an etching such as plasma etching or wet etching. Once the holes have been made, elementary cell cells are placed on the lateral surface of each of these holes, for example, by successive deposition on the lateral surface of each of said holes of a first electrode layer, of a membrane layer and a second electrode layer, and optionally current collectors at the level of each of the electrode layers. According to the invention, the depositing of the electrode layers can be carried out by any known method that allows access to deposits in the form of thin layers. This deposition can be effected, for example, by physical vapor deposition (PVD for Physical Vapor Deposition),
ES 2 289 179 T3 chemical vapor deposition (CVD for Chemical Vapor Deposition), centrifugal coating (spin-coating) or even by immersion of a base layer, for example platinum carbon.
According to the invention, the deposition of the membrane layer can be carried out, for example, by liquid means. The constitutive material of the membrane can be chosen, for example, from a group consisting of polyimides, polyethersulfones, polystyrenes and their derivatives, polyetherketones and their derivatives, polybenzoaxols, polybenzimidazoles and their derivatives, polyarylenes such as paraphenylenes and polyparaxylylenes.
The elementary cells thus constituted are destined to be electrically connected, in order to add the individual electrical powers of each one of them. Additionally, these cells must be fed by reagents. To do this, the method comprises a step of realizing a network of electrical connections and a network for distributing the reagents on at least one of the faces of the support.
To carry out these stages of electrical connections, photolithography techniques, by means of photosensitive resin or photosensitive dry film can be used. Etching techniques can also be considered, particularly heavy ion bombardment etching.
The realization of the reagent distribution network can be carried out by etching channels on at least one of the faces of the support, said channels ensuring the reagent channeling and said channeling can be optimized by the placement of a diffusion layer.
Figure 1 represents a hole 1 of geometry according to the present invention, the hole in the walls of which are arranged layers constituting an elementary cell, during a stage of the process of the invention.
According to this particular mode, the hole 1 has a truncated pyramidal shape, more particularly with a square base and opens from either part of the opposite faces 9a, 9b of a support 9 through a first referenced hole section 1a and a second section 1b hole, being the surface of the first hole section, in this particular case, lower than any of the hole sections taken in a plane parallel to the opposite faces mentioned above and said hole presenting a lateral surface 1c. This hole has a sloping interior profile, which helps to facilitate the stage of making the elementary cells, in relation to a hole whose walls would be perpendicular to the opposite faces of said support.
On the lateral surface 1c of this hole are successively arranged:
- an anodic current collector 2, said current collector being connected on the surface to a network of anode connections which are in the form of tracks 3;
- a first electrode layer 4, which, according to this embodiment, performs the function of anode;
- a membrane layer 5;
- a second electrode layer 6, which plays the role of cathode;
- a cathode current collector 7, connected on the surface to a network of cathode connections, which is presented in the form of tracks 8.
According to the terminology of the invention, the support, provided with holes, within which elementary cells are made constitutes a base module, said module being intended to be assembled into at least one other module, to form at least one level of cavity.
It is pointed out that the term "cavity level", used in the description of the invention, refers to the assembly resulting from the assembly of two base modules defined above.
Figure 2 makes it possible to understand, according to a particular embodiment of the invention, the way in which two base modules are assembled, referenced 9 '. Thus, this figure represents two supports 9 almost identical and parallelepiped in shape, provided with three rows of holes 10, in a truncated pyramidal shape with a square base. Each hole 10 constitutes an elementary cell such as the one previously described in figure 1, the different cells being electrically connected in series by a network of electrical connections 11, 12 (respectively anodic and cathodic) that are presented in the form of tracks, to add the active surfaces of each elemental cell. It is understood that, according to a variant of the invention, the electrical connection between the different cells can be made in parallel. For reasons of ease of representation, the reagent distribution network is not represented in this figure.
Prior to assembly, according to this particular embodiment of the invention, the faces devoid of electrical connection networks and distribution of reagents, of two base modules are covered with a bonding layer 13 that is impervious to reagents. This bonding layer can be, for example, the membrane layer, used particularly for its reagent-tightness properties but also a layer that has adhesive properties, said layer being constituted, for example, by a material chosen from a group constituted
ES 2 289 179 T3 for epoxides, polyimides, silicones, acrylic polymers. Note that the assembly of two base modules must be done in such a way that the holes of one base module are set opposite the holes of the adjacent base module (s), to add the active surface of one hole of one module with the Active surface of the hole of the adjacent module (s). To access this result, the base modules destined to be assembled are positioned, for example, with the help of a double-sided positioning machine, at the level of each module, with a positioning cross system.
Once the positioning has been carried out, the assembly is completed by a stage of integrating the two base modules, said stage being able to be carried out according to different techniques.
Thus, clamping can be considered, particularly when the tie layer placed on at least one of the non-mesh faces of the module does not have sufficient adhesive properties to ensure the cohesion of the two base modules.
The bonding can also be carried out by gluing. Among the feasible sizing techniques, mention may be made of molecular adhesion sizing, adhesion sizing or by welding of polymeric materials of the same nature after treatment near the glass transition temperature. For example, when the tie layer is identical in constitution to the membrane layer, said membrane being made of polymeric material, the solidification can be obtained by heat treatment of the layer at a temperature greater than or equal to the glass transition temperature of the polymer. .
According to the terminology of the invention, the assembly resulting from this step of integrating two base modules constitutes a level of cavities.
In order to obtain stacks that have an even more important relationship between active surface and floor space of said stack, it may be considered, according to the invention, to assemble more than two base modules, for example, by assembling at least two cavity levels or at least one cavity level with at least one base module.
To do this, such assembly advantageously comprises, where appropriate, a stage of camouflage of the electrical connection networks and the distribution of reagents of the faces, destined to be joined by a watertight and insulating layer, a stage of smoothing the o of the faces provided with said networks followed by a step of placing a bonding layer on at least one of the faces, intended to be united and finally by a step of bonding the faces in question.
These same steps are applicable when it comes to assembling two base modules of which at least one of the faces to be joined is provided with a network of anodic and / or cathodic connections and / or distribution of the reagents.
The camouflage stage consists, as its name indicates, in camouflaging the electrical connection networks and the reagent distribution networks, in order to avoid short-circuit problems during the joining of the two faces and reagent leakage problems. .
This stage is, for example, ensured by the placement of a watertight and insulating layer.
The smoothing step consists of flattening the surfaces of the faces provided with nets intended for bonding, for example by laying a smoothing layer or by a mechanical process such as polishing. This smoothing stage is necessary to avoid any problem of surface discontinuity during the assembly of the modules.
A particularly advantageous way of carrying out the invention consists in carrying out the camouflage, smoothing and laying stage of a bonding layer by laying a single layer, which is, for example, either a layer of constitution identical to the membrane, constituted for example by Nafion<sup>®</sup>, or else a layer of inorganic material such as a material chosen from silicon oxide, silicon nitride or even a multilayer made up of these different materials.
Figure 3 illustrates a sectional view of a stack resulting from the joining of two levels of cavities, obtained according to a particular embodiment of the invention.
The holes 14 made at the level of these different base modules are frusto-conical in shape, which corresponds to a hole geometry according to the present invention.
On the lateral surface 14a of each hole 14 one can distinguish the superposition of layers, namely a first electrode layer 15, a membrane layer 16 and a second electrode layer 17.
A layer 18, which corresponds to a watertight joining layer, ensures the tightness between two adjacent base modules 19, thus constituting, by their assembly, a level 20 of cavities. In this configuration, obtained according to a particular embodiment of the invention, layer 18 is identical in constitution to membrane layer 16. I know
ES 2 289 179 T3 points out that according to this particular embodiment, the assembly of two base modules 19, to access a level 20 of cavities, consists of assembling two faces devoid of nets.
A single layer 21, which simultaneously ensures adhesion, tightness, insulation and smoothing, ensures the assembly between two levels 20 of cavities. According to this configuration, obtained according to a particular embodiment of the invention, the single layer 21 is of identical constitution to the membrane layer 16.
The cells of the two levels of cavities are electrically linked to each other by means of networks 22, 23 of electrical connections in series.
The assembly of two base modules to form one level of cavities, as well as two levels of cavities, can be considered in different ways.
Thus, Figures 4A, 4B and 4C illustrate different sectional views of different assembly modes of four base modules. According to these particular embodiments, each of the base modules comprises a plurality of holes, said holes having a frusto-conical shape.
According to figure 4A, each of the two levels 25 of cavities results from the assembly of two base modules 24, particularly by placing them opposite the holes 26 at their bases 27 (represented in solid lines in the figure), said levels being subsequently assembled. by positioning opposite the cavities thus constituted by their vertices 28 (represented in solid lines in the figure).
According to FIG. 4B, each of the levels 25 of cavities results from the assembly of two modules 24, particularly by placing them opposite the holes 26 at their vertices 28, said levels being then assembled, particularly by placing them in front of the cavities thus constituted by their bases 27.
Finally, according to Figure 4C, each of the levels 25 of cavities results from the assembly of two base modules 24 by positioning opposite the holes 26, base 27 against vertex 28, said levels being then assembled by positioning opposite the base cavities 27 against vertex 28 thus formed. These different assembly variants contribute to creating complex cavities, seat of elementary cells constituting the fuel cell, with a large internal surface in relation to the surface of the hole sections of the resulting cavities. Thus, a high active surface is obtained in relation to the apparent surface of the assembly thus formed.
The invention will now be described with reference to the following illustrative and non-limiting example.
Example
The objective is to develop an active surface of 350 cm<sup>2</sup> for an apparent surface of 25 cm<sup>2</sup> and an energy of 10 Wh.
To do this, the support is a monocrystalline silicon plate 400 microns thick, with an apparent surface area of 25 cm.<sup>2</sup>, in which a network of holes is engraved. The holes are made by plasma etching and have a square section of 100 microns per side, an opening surface of 56%, the opening surface corresponding to the ratio between the hollow surface and the total surface and a reduction factor of 80 % between the entrance and exit surfaces of the holes. Therefore, the developed area is seven times larger than the apparent area. The thin layers necessary to make a fuel cell are successively deposited on the flanks of the holes, namely:
- an anode comprising, within the framework of this example, a current collector and a catalyst layer deposited by spraying an active ink;
- a thin electrolyte membrane, in the form of a thin layer of NAFION<sup>®</sup>, deposited by immersion;
- a catalyst layer deposited on the membrane to activate the reaction at the cathode level, followed by a metallic deposit, designed to ensure the collection of the electric current at the cathode level.
The anodic and cathodic connection networks are made, according to this example, on one of the faces of the support, by photolithography techniques with photosensitive resins and photosensitive dry films and the reagent distribution network by etching the channels. After these steps, a basic module is obtained.
The assembly of two base modules is carried out through layers of NAFION<sup>®</sup>, glued after heat treatment at a temperature above the glass transition temperature. A level of cavities is obtained in this way.
The assembly of several cavity levels is ensured by a layer of silicon and completed by a molecular gluing step.
IS 2 289 179 T3
Note that the precise positioning of the modules or the levels of cavities intended to be assembled is carried out with the help of a double-sided positioning machine.
Contents6
3 sheets
Sheet 1 Sheet 2 Sheet 3
17 members in 9 offices
Priority claims5
| Document | Office | Kind | Date |
|---|---|---|---|
| 0114841 | France | A | |
| 0114841 | France | A | |
| 20010014841 | France | – | |
| 028030560114841 | – | – | – |
| FR20010014841 | – | – | – |
Members17
| Document | Office | Kind | |
|---|---|---|---|
| WO03043117A2 | World Intellectual Property Organization (WIPO) | A2 | |
| FR2832549A1 | France | A1 | |
| WO03043117A3 | World Intellectual Property Organization (WIPO) | A3 | |
| FR2832549B1 | France | B1 | |
| EP1456902A2 | European Patent Office (EPO) | A2 | |
| US2005019635A1 | United States of America | A1 | |
| JP2005510019A | Japan | A | |
| CN1615557A | China | A | |
| EP1456902B1 | European Patent Office (EPO) | B1 | |
| AT367659T | Austria | T | |
| ATE367659T1 | Austria | T1 | |
| DE60221281D1 | Germany | D1 | |
| US7270686B2 | United States of America | B2 | |
| ES2289179T3This record | Spain | T3 | |
| DE60221281T2 | Germany | T2 | |
| CN100487968C | China | C | |
| JP4748937B2 | Japan | B2 |
Numbers
- Publication
- 2289179
- Publication, DOCDB
- 2289179
- Publication, EPODOC
- ES2289179T
- Application
- 2803056
- Application, DOCDB
- 02803056
- Application, EPODOC
- ES20020803056T
Titles2
- Spanish
- PILA DE COMBUSTIBLE Y PROCEDIMIENTO DE FABRICACION DE TALES PILAS DE SUPERFICIE ACTIVA IMPORTANTE Y VOLUMEN REDUCIDO.
- English
- FUEL BATTERY AND MANUFACTURING PROCEDURE OF SUCH IMPORTANT ACTIVE SURFACE BATTERIES AND REDUCED VOLUME.
Classification
- CPC, 11
- H01M8/2404
- H01M4/8605
- H01M8/0284
- H01M8/1011
- H01M8/1097
- H01M8/241
- H01M8/2455
- H01M8/1007
- Y10T29/49108
- Y02E60/50
- Y02P70/50
- IPC, 5
- H01M8 24
- H01M4 86
- H01M8 02
- H01M8 04
- H01M8 10