JP2010170914A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell capable of restraining effectively an end part of an expansion metal from being pierced into a diffusion layer base material or a current collecting layer, while maintaining a compression force to a desired value, when stacked, so as to make excellent crossleakage durability. <P>SOLUTION: An electrode body 10 is formed of a film electrode joined body 3, and the gas diffusion layers 4, 4 on an anode side and a cathode side for clamping the film electrode joined body 3, a fuel cell 100 is formed by clamping the electrode body 10 by the expansion metals 5, 5A and separators 7, 7 of forming a gas flow passage layer, and the fuel cells 100 are layered to form the fuel cell. The end part 51a of the expansion metal 5 with a relatively narrow end part area, and one part of the end part 51Aa of the expansion metal 5A with a relatively wide end part area, are matched in a layered direction of the fuel cells 100, in a posture in which the expansion metals 5, 5A on the anode side and the cathode side contacts with the gas diffusion layers 4, 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell, and more particularly to a fuel cell including a porous metal body made of expanded metal as a gas flow path layer.

  A fuel cell of a polymer electrolyte fuel cell includes a membrane electrode assembly (MEA) from an ion-permeable electrolyte membrane and an anode-side and cathode-side catalyst layer (electrode layer) sandwiching the electrolyte membrane. Gas diffusion layers (GDL: Gas Diffusion Layer) for collecting electricity generated by electrochemical reaction while providing fuel gas or oxidant gas to the membrane electrode assembly Is sandwiched to form an electrode body (MEGA), and this electrode body is configured by sandwiching a separator in which linear or meandering gas flow channel grooves are integrally formed. As this separator, there is also a so-called flat type separator in which the gas flow path layer is formed from, for example, an expanded metal or a metal foam sintered body disclosed in Patent Document 1 and separated from the separator. The fuel cell stack is formed by stacking a predetermined number of the fuel cells according to required power.

  In the fuel cell described above, hydrogen gas or the like is provided as a fuel gas to the anode electrode, oxygen or air is provided as the oxidant gas to the cathode electrode, and each electrode has its own gas channel layer (or the gas channel of the separator). The gas flows in the in-plane direction at the groove), and then the gas diffused in the gas diffusion layer is guided to the catalyst layer to cause an electrochemical reaction.

  In assembling the fuel cell, a predetermined number of fuel cells are stacked and stacking is performed by applying a given compressive force from both side ends via tension plates. This compressive force enhances the adhesion at the interface between the constituent members of the fuel cell (such as between the separator and the gas diffusion layer, or between the gas diffusion layer and the membrane electrode assembly), thereby enabling contact resistance at the interface. The size is adjusted so as to reduce it. Furthermore, the relative compressive force at the component interface changes depending on the usage environment of the fuel cell (for example, the component member expands or the gas pressure increases in a high temperature environment during high load power generation). Since the relative compressive force changes with the thickness reduction of the accompanying component, the compressive force desired for stacking is set in consideration of these factors.

  When the compressive force acts on each fuel cell at the time of stacking, the compressive force is transmitted to the membrane electrode assembly and the gas diffusion layer through the gas flow path layer made of a separator or a metal porous body as its constituent members.

  Examples of the metal porous body forming the gas flow path layer include the expanded metal and the metal foam sintered body described above. For example, in the fuel cell having the gas flow path layer made of expanded metal, the above compressive force is expanded metal. It is easy to understand that it acts from the edge of the electrode body side to the gas diffusion layer, for example. This will be described with reference to FIG. 4 illustrating the structure of the fuel cell on the cathode side. In the illustrated fuel cell, a membrane electrode assembly a is formed from an electrolyte membrane a1 and a cathode-side and anode-side catalyst layer a2, and this is formed into a cathode comprising a diffusion layer base material b1 and a current collecting layer b2 (MPL). An electrode body c is formed by sandwiching the gas diffusion layer b on the side and the anode side, an expanded metal e serving as a gas flow path layer contacts the gas diffusion layer b, and a flat type separator having a three-layer structure, for example, The fuel cell is constituted by contact of f. In general, a protective film d is interposed between the diffusion layer substrate b1 and an exposed region of the peripheral edge of the electrolyte membrane a1 that is not covered with the catalyst layer a2, and this is the diffusion layer substrate. It effectively protects the fluff protruding from d1 from piercing the electrolyte membrane a1.

  When a predetermined number of illustrated fuel cells are stacked and stacked, a compression force P (fastening force) at the time of stacking acts on the expanded metal e and the electrode body c via the separator f. It becomes. Here, in the expanded metal e, on the side surface that comes into contact with the diffusion layer base material b1, a large number of edges protrude toward the diffusion layer base material side as shown in the figure, and the compressive force P described above applies these edges. The diffusion layer base material b1 is intensively pressed through (concentrated load P1). Here, among the expanded metals e and e on the anode side and the cathode side, the concentrated loads P1 and P1 acting from the corresponding edges may be offset as shown in the figure (separation: t). Due to the load, a shearing force acts on the membrane electrode assembly, which causes a problem that the edge of the expanded metal pierces the gas diffusion layer or the like, or the piercing of the edge is promoted. ing.

  In order to eliminate the above-mentioned problems, if the compression force at the time of stacking is reduced to prevent edge sticking, the contact resistance at the interface between the components of the fuel cell increases due to insufficient compression force (fastening force). Therefore, this is not an appropriate coping approach because it directly affects the power generation performance of the fuel cell.

JP 2005-293944 A

  The present invention has been made in view of the above-described problems, and a compressive force acts intensively from the end of the expanded metal forming the gas flow path layer while maintaining a given compressive force during stacking. Even when the diffusion layer base material of the gas diffusion layer or the diffusion layer base material is not present, the end of the expanded metal pierces the current collecting layer, and further, the membrane electrode assembly is pierced by the piercing of the end portion. It is an object of the present invention to provide a fuel cell capable of effectively suppressing problems such as damage to the gas and formation of a gas cross leak path.

  In order to achieve the above object, a fuel cell according to the present invention is an expander in which an electrode body is formed from a membrane electrode assembly and an anode-side and cathode-side gas diffusion layer sandwiching the membrane-electrode assembly to form a gas flow path layer. In a fuel cell in which a porous metal body made of metal and a separator sandwich the electrode body to form a fuel cell, and the fuel cell is laminated, gas diffusion is performed in the expanded metal on the anode side and the cathode side. The end areas of the expanded metal that are in contact with the layers are different, and in the posture in which both expanded metals are in contact with the gas diffusion layer, the end portions of the expanded metal having a relatively small end area and the end area A part of the end portion of the relatively large expanded metal coincides in the stacking direction of the fuel cells.

  The fuel cell constituting the fuel cell according to the present invention has expanded metal on the anode side and the cathode side that are different from each other in the area of the end portion where the expanded metal contacts the gas diffusion layer. This occurs when both ends (the edges) are set off as in the prior art described above by matching a part of the end with the end of the other expanded metal in the cell stacking direction. Thus, the fuel cell can effectively prevent the end of the expanded metal from sticking into the gas diffusion layer by suppressing the generation of the shearing force to be obtained.

  Here, the porous metal body made of expanded metal is intermittently sheared while continuously extruding the metal plate, and when the metal plate (metal mesh) after shearing is stretched, pores such as trapezoids and rhombuses are formed. The porous body which has is formed. When viewed in a longitudinal section, the metal mesh that defines the pores has an aspect in which inclined metal beams (the ends of the metal beams become the above-mentioned edges) are arranged intermittently. In this processing, for example, in the expanded metal in which both the anode side and the cathode side expanded metal are processed from a metal plate having the same thickness and the end contact area with the gas diffusion layer is relatively wide, The contact area can be increased by performing a process such as bending the end part or expanding the area by heating and melting. As another method, an expanded metal whose end area in contact with the gas diffusion layer is desired to be relatively wide may be processed from a thick metal plate that is relatively thicker than the other expanded metal. . In this method, the end portion after the shearing process may be further bent or heated and melted.

  Further, another embodiment of the fuel cell according to the present invention comprises a membrane electrode assembly and a current collecting layer and a diffusion layer base material disposed on either the anode side or the cathode side sandwiching the membrane electrode assembly. An electrode body is formed from a gas diffusion layer and a current collecting layer disposed on the other side, and a porous metal body made of expanded metal forming a gas flow path layer and a separator sandwich the electrode body to form a fuel cell. In the fuel cell formed by stacking the fuel battery cells, the expanded metal on the anode side and the cathode side have different end areas in contact with the gas diffusion layer or the current collecting layer, When the expanded metal is in contact with the gas diffusion layer or the current collecting layer, the end of the expanded metal having a relatively small end area and the expanded having a relatively large end area Some of the end portion of the barrel is intended to match in the laminating direction of the fuel cell.

  In the fuel cell constituting the fuel cell of the present embodiment, the gas diffusion layer on either the anode side or the cathode side does not include the diffusion layer base material, that is, one from the diffusion layer base material and the current collector. The fuel cell having the gas diffusion layer and the other having only the current collecting layer.

  In the present embodiment, even when a diffusion layer base material that can be elastically deformed in only one of the two electrodes exists in the constituent members of the fuel cell, the compressive force is applied to the membrane by the elastic deformation. The other diffusion layer base material is abolished under the idea that it can be uniformly applied to one surface of the electrode assembly. For example, on the cathode side where a chemical reaction between protons and oxygen occurs, the diffusion layer base is formed on the cathode side in accordance with the design philosophy of making the compressive force acting on the membrane electrode assembly as uniform as possible in the plane. A gas diffusion layer having a material is preferably provided, and only a current collecting layer is provided on the anode side.

  Here, the current-collecting layer on the electrode side that does not include the diffusion layer base material can ensure its workability (handling property), for example, by manufacturing it as a sheet (or film). A current collecting layer can be provided on one surface of the membrane electrode assembly by hot-pressing the produced film-like current collecting layer on the surface of the catalyst layer. This current collecting layer is composed of conductive materials such as platinum, palladium, ruthenium, rhodium, iridium, gold, silver, copper and their compounds or alloys, conductive carbon (carbon) materials, and fluororesins. It can be formed from a water repellent polymer.

  Further, in a preferred embodiment of the fuel cell according to the present invention, the end area of the expanded metal on the anode side is relatively large.

  As described above, in an electrode having an expanded metal with a wide end area in contact with the gas diffusion layer or the current collecting layer, the gas flowing in the layer direction of the expanded metal wraps around the end with a relatively large area. Thus, since it is provided to the membrane / electrode assembly, the gas supply efficiency to the membrane / electrode assembly is likely to decrease naturally. In addition, considering the fact that oxygen is relatively difficult to flow because of its relatively large molecules compared to hydrogen and that the generated water tends to stay on the cathode side, the end of the expanded metal on the anode side By making the area relatively large, the generation of the above-mentioned shear force is prevented without lowering the efficiency of oxygen supply to the membrane electrode assembly, and hence without reducing the power generation performance, and thus the cross leak durability. A high-performance fuel cell can be obtained.

  According to the fuel cell of the present invention described above, the compression force at the time of stacking is maintained at a desired value (reducing the compression force at the time of stacking) by a simple structural change by simply improving a part of the expanded metal structure. The end of the expanded metal is pierced into at least the power generation region of the electrode body (diffusion layer substrate or current collecting layer), and the membrane electrode assembly is damaged by the piercing of the end, It is possible to effectively solve the problem of forming a cross leak path.

  As can be understood from the above description, according to the fuel cell of the present invention, the end of the expanded metal is stuck into the diffusion layer base material or the current collecting layer while maintaining the compression force at the time of stacking at a desired value. A fuel cell that can be effectively suppressed and has excellent cross leak durability can be obtained.

It is a longitudinal cross-sectional view of one embodiment of the fuel cell constituting the fuel cell of the present invention. It is a longitudinal cross-sectional view of other embodiment of the fuel cell which comprises the fuel cell of this invention. It is a longitudinal cross-sectional view of further another embodiment of the fuel cell which comprises the fuel cell of this invention. In the conventional fuel cell, it is the figure explaining the state in which the metal porous body which consists of an expanded metal has pierced the diffusion layer base material.

  Embodiments of the present invention will be described below with reference to the drawings. In the illustrated example, the end of the expanded metal on the anode side is bent or the like, but the end of the expanded metal on the cathode side is bent or the like in addition to this form. May be.

  FIG. 1 is a longitudinal sectional view of an embodiment of a fuel cell constituting the fuel cell of the present invention. The structure of the fuel cell 100 shown in FIG. 1 is that a membrane electrode assembly 3 is formed from an electrolyte membrane 1 that is an ion exchange membrane and catalyst layers 2 and 2 on the cathode side and the anode side. The electrode body 10 is formed by sandwiching the gas diffusion layers 4, 4, and the electrode body 10 is sandwiched between the cathode-side and anode-side gas flow path layers 5, 5. The separators 7 and 7 having a three-layer structure are sandwiched, and a resin gasket 8 is integrally formed on the periphery of the electrode body 10. Further, the area of the catalyst layer 2 is smaller than that of the electrolyte membrane 1, and therefore, there is an exposed region where the catalyst layers 2, 2 do not exist at the periphery of the catalyst layers 2, 2 on both sides of the electrolyte membrane 1. In this exposed region, cathode-side and anode-side protective films 6, 6 are arranged to prevent fluff protruding from the gas diffusion layers 4, 4 from sticking into the electrolyte membrane 1. .

  Here, the electrolyte membrane 1 constituting the membrane electrode assembly 3 includes, for example, a fluorine ion exchange membrane having a sulfonic acid group or a carbonyl group, a substituted phenylene oxide, a sulfonated polyaryletherketone, a sulfonated polyarylethersulfone, It is formed from a non-fluorine polymer such as sulfonated phenylene sulfide. The catalyst layer 2 is a mixture of a conductive carrier (particulate carbon carrier or the like) on which a catalyst is supported, an electrolyte, and a dispersion solvent (organic solvent) to produce a catalyst solution (catalyst ink). The catalyst layer is formed by stretching this on a base material such as the electrolyte membrane 1 or the gas diffusion layer 4 in a layer shape with a coating blade to form a coating film and drying it in a hot air drying furnace or the like. Here, the electrolyte forming the catalyst solution is a proton conductive polymer, an ion exchange resin having a skeleton of an organic fluorine-containing polymer, such as a perfluorocarbon sulfonic acid resin, a sulfonated polyether ketone, a sulfonated polyether. Sulfonated plastic electrolytes such as sulfone, sulfonated polyetherethersulfone, sulfonated polysulfone, sulfonated polysulfide, sulfonated polyphenylene, sulfoalkylated polyetheretherketone, sulfoalkylated polyethersulfone, sulfoalkylated polyetherethersulfone And sulfoalkylated plastic electrolytes such as sulfoalkylated polysulfone, sulfoalkylated polysulfide, and sulfoalkylated polyphenylene. Examples of commercially available materials include Nafion (registered trademark, manufactured by DuPont) and Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.). Examples of the dispersion solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, and diethylene glycol, acetone, methyl ethyl ketone, dimethylformamide, dimethylimidazolidinone, dimethyl sulfoxide, dimethylacetamide, and N-methylpyrrolidone. , Propylene carbonate, esters such as ethyl acetate and butyl acetate, and various aromatic or halogen solvents, and these can be used alone or as a mixed solution. Furthermore, regarding a conductive carrier carrying a catalyst, examples of the conductive carrier include carbon materials such as carbon black, carbon nanotubes, and carbon nanofibers, and carbon compounds typified by silicon carbide. As this catalyst (metal catalyst), for example, any one of platinum, platinum alloy, palladium, rhodium, gold, silver, osmium, iridium, etc. can be used, preferably platinum or platinum alloy is used. It is good to do. Furthermore, as this platinum alloy, for example, platinum, aluminum, chromium, manganese, iron, cobalt, nickel, gallium, zirconium, molybdenum, ruthenium, rhodium, palladium, vanadium, tungsten, rhenium, osmium, iridium, titanium and lead An alloy with at least one of them can be mentioned.

  The gas diffusion layer 4 for diffusing and providing the oxidant gas and fuel gas flowing through the gas flow path layer 5 to the membrane electrode assembly 3 includes a diffusion layer base material 41 and a current collecting layer 42 (MPL). The diffusion layer base material 41 is not particularly limited as long as it has a low electrical resistance and can collect current. For example, a material mainly composed of a conductive inorganic substance can be cited. Examples of the conductive inorganic substance include a fired body from polyacrylonitrile, a fired body from pitch, carbon materials such as graphite and expanded graphite, nanocarbon materials thereof, stainless steel, molybdenum, titanium, and the like. The form of the conductive inorganic substance of the diffusion layer base material 41 is not particularly limited. For example, the conductive inorganic substance is used in the form of fibers or particles, but is an inorganic conductive fiber from the viewpoint of gas permeability. Fiber is preferred. As the diffusion layer base material 41 using inorganic conductive fibers, a woven fabric or non-woven fabric structure can be used, and examples thereof include carbon paper and carbon cloth. The woven fabric is not particularly limited, such as plain weaving, crest weaving, and binding weaving, and examples of the nonwoven fabric include those made by a papermaking method, a needle punching method, and a water jet punching method. Further, examples of the carbon fiber include phenol-based carbon fiber, pitch-based carbon fiber, polyacrylonitrile (PAN) -based carbon fiber, and rayon-based carbon fiber. Further, the current collecting layer 42 serves as an electrode for collecting electrons from the catalyst layers 2 and 2 on the anode side and the cathode side, and is made of platinum, palladium, ruthenium, rhodium, iridium, gold, silver, which are conductive materials. , Copper and their compounds or alloys, conductive carbon materials, and the like.

  The protective film 6 is made of polytetrafluoroethylene, PVDF (polyvinyl difluoride), polyethylene, polyethylene naphthalate (PEN), polycarbonate, polyphenylene ether (PPE), polypropylene, polyester, polyamide, copolyamide, polyamide elastomer, polyimide. , Polyurethane, polyurethane elastomer, silicone, silicone rubber, silicon-based elastomer and the like.

  In addition, the gasket 8 provided in a region defined by the separator 7 and the electrode body 10 at the periphery of the electrode body accommodates the electrode body in, for example, a molding die, and injection-molds a resin at the periphery. Molded. Here, the gasket 8 is formed of a resin material such as butyl rubber, urethane rubber, silicone RTV rubber, epoxy resin having methanol resistance, epoxy-modified silicone resin, silicone resin, fluorine resin, or hydrocarbon resin. The

  Further, the separator 7 is interposed between the cathode side plate 71, the anode side plate 73, and the plates 71, 73 that define the cells between adjacent fuel cells, and And a spacer 72 formed in a frame shape (endless shape) along the outer periphery contour. The plates 71 and 73 are made of a conductive metal such as stainless steel or titanium, and the spacer 72 is made of the same conductive metal or resin. In one embodiment, a large number of dimples are provided on the side surface of the plate 71 facing the plate 73, and the dimple has a height corresponding to the thickness of the spacer 72, resulting in a three-layer structure. In some cases, the tip of the dimple is brought into contact with the side surface of the plate 73 to form a coolant channel. As another form, there is a form in which a linear or meandering refrigerant flow path is formed in the spacer 72. In this three-layer structure separator, a unique manifold M is formed in which each of fuel gas, oxidant gas, and refrigerant flows into the separator and then flows out, and is in fluid communication with the manifold M formed coaxially with the gasket 8. is doing. In addition, the endless rib 81 is formed in the periphery of the manifold M among the gaskets 8, and the fluid seal structure is formed when the separator 7 presses this.

  The gas flow path layer 5 shown in FIG. 1 is formed from expanded metal. This is done by continuously extruding a metal plate on a rotating roll, intermittently performing shearing, and then stretching the metal plate (metal mesh) after shearing to form pores such as trapezoids and rhombuses. The cathode-side expanded metal 5 and the anode-side expanded metal 5A are formed. For example, when the expanded metal 5 on the cathode side is viewed in a longitudinal section, the metal mesh that defines the pores is inclined as shown in the figure by a metal beam 51, which is inclined (further edge of the end 51a of the metal beam 51). Are in contact with the diffusion layer base material 41 (not shown, but when viewed from the direction orthogonal to the figure, the metal beam defines a trapezoid or rhombus shape). A large number of pores made visible).

  On the other hand, the metal beam 51A constituting the expanded metal 5A on the anode side is bent or the like so that the end portion 51Aa in contact with the diffusion layer base material 41 widens the contact area. The contact area of the end portion 51Aa of the expanded metal 5A on the anode side with the diffusion layer base material 41 is relatively wide, so that a part of the end portion 51Aa and the metal beam of the expanded metal 5 on the cathode side facing the end portion 51Aa. As shown in the figure, the end 51a of 51 can coincide with the line L in the stacking direction (vertical direction in the figure) of the fuel cells 100. Thereby, even when the compressive force at the time of stacking acts on the fuel cell 100 and the concentrated load acts on the diffusion layer base material 41 via the end 51Aa and the end 51a, the end 51Aa and the end 51a Since there is no deviation, no shear force is generated between the two. Therefore, it is possible to effectively suppress the occurrence of cracks in the constituent members of the electrode body 10 including the diffusion layer base material 41 due to the shear force, or the promotion of crack generation.

  In an actual fuel cell stack, the illustrated fuel cell 100 is stacked in a number corresponding to the required power (for example, 200 to 400) to form a cell stack, end plates are arranged on both sides, Plates, insulators and the like are stacked and formed by stacking with a given compression force. A fuel cell system mounted on an electric vehicle or the like includes this fuel cell, various tanks for storing hydrogen gas and air, a blower for supplying these gases to the fuel cell, a radiator for cooling the fuel cell, a fuel The battery is generally composed of a battery that stores electric power generated by the battery, a drive motor that is driven by the electric power, and the like.

FIG. 2 is a longitudinal sectional view showing another embodiment of the fuel cell.
The fuel cell 100A and the fuel cell 100 are different in that the expanded metal 5B on the anode side is processed from a metal material thicker than the expanded metal 5 on the cathode side, and therefore the expanded metal 5B is sheared. In this stage, the width of the end portion 51Ba of the metal beam 51B is relatively large. Needless to say, the end 51Ba may be further bent.

  Also in the fuel cell 100A, in the expanded metals 5 and 5B on both the anode side and the cathode side, the end portions 51a and 51Ba of the opposing metal beams 51 and 51B coincide with each other in a line L along the cell stacking direction. Therefore, like the fuel cell 100, no shear force is generated between the two.

FIG. 3 is a longitudinal sectional view showing still another embodiment of the fuel cell.
This fuel battery cell 100B is a fuel battery cell that has expanded metal 5 and 5B having different thicknesses as in the fuel battery cell 100A, but has a structure in which the anode side diffusion layer base material is discarded. According to this fuel cell 100B, in addition to the effect of avoiding the generation of the shearing force described above, the thickness (height) of the entire fuel cell can be reduced, and thus the physique of the fuel cell stack formed by stacking the fuel cells. Reduction can also be achieved.

  According to the fuel cell 100, 100A, 100B described above, by an extremely simple structural change that only widens the area of the end portion in contact with the gas diffusion layer or the current collecting layer of the expanded metal on the anode side by bending or the like, The problem that the end portion of the expanded metal pierces the diffusion layer base material or the like due to the compressive force acting at the time of stacking, and the cross leak durability of the fuel cell stack is lowered can be effectively solved.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Electrolyte membrane, 2 ... Catalyst layer, 3 ... Membrane electrode assembly, 4 ... Gas diffusion layer, 41 ... Diffusion layer base material, 42 ... Current collection layer (MPL), 5 ... Gas flow path layer (metal porous body, (Expanded metal), 51, 51A, 51B ... metal beam, 51a, 51Aa, 51Ba ... end, 6 ... protective film, 7 ... separator, 71 ... cathode side plate, 72 ... intermediate plate, 73 ... anode side plate, 8 ... Gasket, 81 ... endless rib, 10 ... electrode body, 100, 100A, 100B ... fuel cell, M ... manifold

Claims (3)

An electrode body is formed from a membrane electrode assembly and anode-side and cathode-side gas diffusion layers sandwiching the membrane-electrode assembly, and a porous metal body made of expanded metal and a separator sandwiching the electrode body sandwiching the electrode body A fuel cell, and a fuel cell formed by stacking the fuel cells,
In the expanded metal on the anode side and the cathode side, the respective end areas in contact with the gas diffusion layer are different. The fuel cell, wherein the end of the metal and a part of the end of the expanded metal having a relatively large end area coincide with each other in the stacking direction of the fuel cells. A membrane electrode assembly, a gas diffusion layer composed of a current collection layer and a diffusion layer base material disposed on either the anode side or the cathode side sandwiching the membrane electrode assembly, and a current collection layer disposed on the other side, A fuel cell is formed by forming a fuel cell by sandwiching the electrode body with a porous metal body made of expanded metal forming a gas flow path layer and a separator, and forming a fuel cell. In batteries,
In the expanded metal on the anode side and the cathode side, the respective end areas in contact with the gas diffusion layer or the current collection layer are different, and in the posture in which both expanded metals are in contact with the gas diffusion layer or the current collection layer, the end The fuel cell, wherein the end portion of the expanded metal having a relatively small area and the part of the end portion of the expanded metal having a relatively large end area coincide with each other in the stacking direction of the fuel cells.   The fuel cell according to claim 1 or 2, wherein the end area of the expanded metal on the anode side is relatively large.

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