JP2015050056A - Fuel cell and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to suppress gas permeation from an outer peripheral part of a gas diffusion layer as much as possible with a simple configuration and process.SOLUTION: An electrolyte membrane-electrode structure 12 constituting a fuel cell 10 includes an anode electrode 40 and a cathode electrode 42. The anode electrode 40 and the cathode electrode 42 include a first gas diffusion layer 40b and a second gas diffusion layer 42b constituted of a porous sheet obtained by forming a paste containing a carbon material and a non-hydrophilic resin in a sheet shape. A first gas impermeable sheet 44a and a second gas impermeable sheet 44b are joined to a first gas impermeable processed part 40bs and a second gas impermeable processed part 42bs formed in outer peripheral parts of the first gas diffusion layer 40b and the second gas diffusion layer 42b.

Description

  The present invention relates to a fuel cell in which an electrolyte membrane / electrode structure in which an electrode having an electrode catalyst layer and a gas diffusion layer is provided on both surfaces of a solid polymer electrolyte membrane, and a separator, and a method for manufacturing the same.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell has an electrolyte membrane / electrode structure (MEA) in which an anode electrode and a cathode electrode each made of an electrode catalyst (electrode catalyst layer) and porous carbon (gas diffusion layer) are disposed on both sides of a solid polymer electrolyte membrane. ). The electrolyte membrane / electrode structure constitutes a power generation cell by being sandwiched between separators (bipolar plates). Normally, in a fuel cell, a fuel cell stack in which a predetermined number of power generation cells are stacked is used as, for example, an in-vehicle fuel cell stack.

  In the electrolyte membrane / electrode structure, the fuel gas and the oxidant gas are easy to permeate, and it is necessary to suppress the mixing of the fuel gas and the oxidant gas between the two electrodes (so-called cross leak). For this reason, for example, an electrode-electrolyte membrane assembly disclosed in Patent Document 1 is known.

  In this electrode-electrolyte membrane assembly, the catalyst layer and the gas barrier resin film are formed to have the same film thickness on one or both surfaces of the polymer electrolyte membrane, and the gas diffusion base material is further formed on the catalyst layer and the gas barrier resin film. Is formed. And the gas barrier resin film is formed in the outer peripheral part of the catalyst layer, and the said gas barrier resin film contains the heat adhesive resin film.

Japanese Patent No. 5130690

  By the way, in the fuel cell, the thickness of the catalyst layer is often configured to be considerably thin. For this reason, the gas barrier resin film which goes around the catalyst layer and is interposed between the polymer electrolyte membrane and the gas diffusion base material needs to be formed in a considerably thin shape. Therefore, the thin gas barrier resin film has a problem that a desired gas impermeability function cannot be obtained.

  The present invention solves this type of problem, and provides a fuel cell capable of suppressing gas permeation from the outer periphery of a gas diffusion layer as much as possible with a simple configuration and process, and a method for manufacturing the same. The purpose is to provide.

  The present invention relates to a fuel cell in which an electrolyte membrane / electrode structure in which electrodes having an electrode catalyst layer and a gas diffusion layer are provided on both sides of a solid polymer electrolyte membrane, and a separator, and a method for manufacturing the same. .

  In this fuel cell, the gas diffusion layer is composed of a porous sheet in which a paste containing a carbon material and a non-hydrophilic resin is formed into a sheet shape. And the thin part thinner than a center part is formed in the outer peripheral part of a porous sheet by press work, and the gas impervious sheet is joined to the said thin part.

  In this fuel cell, it is preferable that the gas impermeable sheet is bonded to at least one of the electrode catalyst layer side surface and the separator side surface in the thin portion.

  Furthermore, this manufacturing method has the process of forming the porous sheet | seat which is a gas diffusion layer by forming the paste containing a carbon material and non-hydrophilic resin in a sheet form. This manufacturing method then has a step of providing a thin portion thinner than the central portion on the outer peripheral portion of the porous sheet and joining a gas-impermeable sheet to the thin portion.

  Furthermore, in this manufacturing method, a thin-walled portion is provided on the outer peripheral portion of the porous sheet by performing a pressing process in a state in which the gas-impermeable sheet is disposed on the outer peripheral portion of the porous sheet, and the gas impermeable sheet is provided. It is preferable to press-bond the transmission sheet.

  Moreover, in this manufacturing method, it is preferable to have the process of providing a thin part by performing press processing to the outer peripheral part of a porous sheet, and the process of joining a gas impervious sheet to the said thin part.

  Furthermore, in this manufacturing method, it is preferable that a gas-impermeable sheet is bonded to at least one of the electrode catalyst layer side surface and the separator side surface in the thin portion.

  According to the present invention, the gas diffusion layer is composed of a porous sheet in which a paste containing a carbon material and a non-hydrophilic resin is formed into a sheet shape. Therefore, unlike the gas diffusion layer composed of carbon paper, the carbon fibers at the end portions do not pierce the solid polymer electrolyte membrane, and the solid polymer electrolyte membrane can be well protected.

  In addition, a thin-walled portion whose gas permeability is reduced by pressing is formed on the outer peripheral portion of the porous sheet, and a gas-impermeable sheet is joined to the thin-walled portion. Therefore, the gas diffusion layer can be provided with a gas impermeable function by the thin wall portion and the gas impermeable sheet, and suppress gas transmission from the outer peripheral portion of the gas diffusion layer as much as possible with a simple configuration and process. It becomes possible to do.

It is a principal part disassembled perspective view of the fuel cell which concerns on the 1st Embodiment of this invention. It is the II-II sectional view taken on the line of the said fuel cell in FIG. It is a disassembled perspective explanatory drawing of the electrolyte membrane and electrode structure which comprises the said fuel cell. It is explanatory drawing of the mounting body by which the gas impervious sheet was mounted on the electroconductive porous sheet which comprises the said electrolyte membrane and electrode structure. It is explanatory drawing of the state which has arrange | positioned the said mounting body between the pressurization plates. It is explanatory drawing at the time of pressurizing between the said pressurization plates. In the manufacturing method which concerns on the 2nd Embodiment of this invention, it is explanatory drawing of the mounting body by which the sheet | seat for press was mounted on the said electroconductive porous sheet. It is explanatory drawing of the state which has arrange | positioned the said mounting body between the pressurization plates. It is explanatory drawing at the time of pressurizing between the said pressurization plates. It is explanatory drawing of the mounting body in which the other press sheet was arrange | positioned instead of the said press sheet. It is explanatory drawing of the state which has arrange | positioned the said mounting body between the pressurization plates. It is explanatory drawing at the time of pressurizing between the said pressurization plates. It is a section explanatory view of a fuel cell concerning a 3rd embodiment of the present invention. It is a section explanatory view of a fuel cell concerning a 4th embodiment of the present invention.

  As shown in FIG. 1, in the fuel cell 10 according to the first embodiment of the present invention, the electrolyte membrane / electrode structure 12, the anode-side separator 14 and the cathode-side separator 16 are in the standing posture in the direction of arrow A ( For example, they are stacked in the horizontal direction). By stacking the plurality of fuel cells 10 in the direction of arrow A, for example, an in-vehicle fuel cell stack is configured. The fuel cell 10 may be stacked in the direction of arrow C (vertical direction).

  The anode side separator 14 and the cathode side separator 16 have a horizontally long shape, but may have a vertically long shape. As the anode side separator 14 and the cathode side separator 16, for example, a carbon separator or a metal separator is used.

  The fuel cell 10 is provided with an oxidant gas inlet communication hole 18a and a fuel gas outlet communication hole 20b at one end edge in the arrow B direction (horizontal direction) so as to communicate with each other in the direction of arrow A which is the stacking direction. The oxidant gas inlet communication hole 18a supplies an oxidant gas, for example, an oxygen-containing gas. The fuel gas outlet communication hole 20b discharges fuel gas, for example, hydrogen-containing gas. The oxidant gas inlet communication hole 18a and the fuel gas outlet communication hole 20b are arranged in the direction of arrow C (vertical direction).

  The other end edge of the fuel cell 10 in the direction of the arrow B communicates with each other in the direction of the arrow A, the fuel gas inlet communication hole 20a for supplying the fuel gas, and the oxidant gas outlet for discharging the oxidant gas. The communication holes 18b are arranged in the direction of arrow C.

  A cooling medium inlet communication hole 22a for supplying a cooling medium is provided at one end edge (upper end edge) in the arrow C direction of the fuel cell 10. The other end edge (lower end edge) in the direction of arrow C of the fuel cell 10 is provided with a cooling medium outlet communication hole 22b for discharging the cooling medium.

  A fuel gas passage 24 communicating with the fuel gas inlet communication hole 20a and the fuel gas outlet communication hole 20b extends in the direction of arrow B on the surface 14a of the anode separator 14 facing the electrolyte membrane / electrode structure 12. Provided. An inlet buffer portion 24 a is provided on the inlet side of the fuel gas passage 24, while an outlet buffer portion 24 b is provided on the outlet side of the fuel gas passage 24.

  An oxidant gas flow path 30 communicating with the oxidant gas inlet communication hole 18a and the oxidant gas outlet communication hole 18b is formed in the direction of arrow B on the surface 16a of the cathode separator 16 facing the electrolyte membrane / electrode structure 12. It is extended and provided. The oxidant gas channel 30 is configured in the same manner as the fuel gas channel 24, and a detailed description thereof is omitted.

  The anode-side separator 14 and the cathode-side separator 16 integrally form a cooling medium flow path 32 between the faces 14b, 16b facing each other. The cooling medium flow path 32 is provided extending in the direction of arrow C.

  A first seal member 34 is integrally or individually provided on the surfaces 14 a and 14 b of the anode separator 14 so as to go around the outer peripheral edge of the anode separator 14. On the surfaces 16a and 16b of the cathode side separator 16, a second seal member 36 is integrally or individually provided around the outer peripheral edge of the cathode side separator 16.

  For the first seal member 34 and the second seal member 36, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  The electrolyte membrane / electrode structure 12 has a horizontally long shape, for example, a solid polymer electrolyte membrane 38 in which a thin film of perfluorosulfonic acid is impregnated with water, and an anode electrode 40 sandwiching the solid polymer electrolyte membrane 38. And a cathode electrode 42. The outer dimensions of the solid polymer electrolyte membrane 38 are set larger than the outer dimensions of the anode electrode 40 and the cathode electrode 42. Note that the anode electrode 40 and the cathode electrode 42 may be configured to have a so-called step MEA by being set to have different sizes. As the solid polymer electrolyte membrane 38, an HC (hydrocarbon) electrolyte is used in addition to a fluorine electrolyte.

  As shown in FIG. 2, the anode electrode 40 includes a first electrode catalyst layer 40a formed on one surface 38a of the solid polymer electrolyte membrane 38, and a microporous layer (MPL) composed of a conductive porous sheet. ) (Micro Porous Layer). The conductive porous sheet is obtained by forming a paste containing a carbon material and a non-hydrophilic resin into a sheet shape. Similarly, the cathode electrode 42 includes a second electrode catalyst layer 42a formed on the other surface 38b of the solid polymer electrolyte membrane 38, and a microporous layer (MPL) composed of a conductive porous sheet. 2 gas diffusion layers 42b.

  The first gas diffusion layer 40b and the second gas diffusion layer 42b have a thickness in the range of 50 μm to 250 μm, preferably 80 μm to 180 μm, and contain an electron conductive substance and a non-hydrophilic resin (water repellent resin). It has conductivity. As the electron conductive substance, for example, carbon fiber or carbon powder (carbon black, furnace black, acetylene black, carbon nanotube, etc.) is used alone or in combination of two or more. Non-hydrophilic resins include crystalline fluororesin (ETFT) (tetrafluoroethylene / ethylene copolymer), PVDF (polyvinylidene fluoride), PVF (polyvinyl fluoride), ECTFE (chlorotrifluoroethylene / ethylene copolymer). ), PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), amorphous fluororesin and silicone resin, polyethylene, Contains at least one such as polypropylene.

  As shown in FIGS. 2 and 3, the outer peripheral portion of the first gas diffusion layer 40b and the outer peripheral portion of the second gas diffusion layer 42b are first thin portions having a frame shape that is thinner than the central portion by press working. A gas impermeable processing unit 40bs and a second gas impermeable processing unit 42bs are formed. The first gas impermeable processing unit 40bs and the second gas impermeable processing unit 42bs are in contact with the solid polymer electrolyte membrane 38, and a space is provided between the anode side separator 14 side and the cathode side separator 16.

  The first gas impermeable sheet 44a and the second gas impermeable sheet 44b are joined to the first gas impermeable processing section 40bs and the second gas impermeable processing section 42bs in correspondence with each space. That is, the first gas impermeable sheet 44a and the second gas impermeable sheet 44b are bonded (for example, press bonded) to the separator-side surfaces of the first gas impermeable processing unit 40bs and the second gas impermeable processing unit 42bs. The

  The first gas impermeable sheet 44a and the second gas impermeable sheet 44b are made of a non-hydrophilic resin. For example, crystalline fluororesin (ETFT) (tetrafluoroethylene / ethylene copolymer), PVDF (polyvinylidene fluoride), PVF (polyvinyl fluoride), ECTFE (chlorotrifluoroethylene / ethylene copolymer), PTFE (poly) At least one of tetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), amorphous fluororesin and silicone resin, polyethylene, polypropylene, etc. Contains seeds.

  The first gas impermeable sheet 44a and the second gas impermeable sheet 44b may be a film made of PEN (polyethylene naphthalate), a film made of PET (polyethylene terephthalate), or the like.

  As shown in FIG. 2, the sum of the thickness t1a of the first gas impervious treatment section 40bs and the thickness t2a of the first gas impervious sheet 44a is the same as the first gas diffusion layer 40b and the first electrode catalyst layer 40a. It is set equal to the added thickness. The sum of the thickness t1b of the second gas impermeable processing section 42bs and the thickness t2b of the second gas impermeable sheet 44b is set to be equal to the thickness obtained by adding the second gas diffusion layer 42b and the second electrode catalyst layer 42a. Is done. The surface positions of the first gas impermeable sheet 44a and the second gas impermeable sheet 44b are arranged at the same position as the surface positions of the first gas diffusion layer 40b and the second gas diffusion layer 42b, and the same plane with no step as a whole. Form.

  Next, the manufacturing method according to the first embodiment will be described below.

  First, as shown in FIG. 4, the conductive porous sheet 50 constituting the first gas diffusion layer 40b and the second gas diffusion layer 42b is produced. Specifically, after carbon black was added to an aqueous solution and dispersed by stirring, the PTFE dispersion solution was added and mixed so that the weight ratio of PTFE and carbon black was 7: 3. After PTFE and carbon black were aggregated from the obtained dispersion and subjected to a drying treatment, for example, a sheet having a thickness of 130 μm was formed, and the conductive porous sheet 50 was obtained.

  A first gas-impermeable sheet 44a is placed on one conductive porous sheet 50 to obtain a mounting body 52a, and a second gas-impermeable sheet is placed on the other conductive porous sheet 50. The sheet 44b is placed to obtain the placement body 52b (see FIG. 4). As shown in FIG. 5, the mounting bodies 52a and 52b are sandwiched between the pressure plates 54a and 54b. The pressure plates 54 a and 54 b are provided with a PTFE sheet 58 and a polyimide sheet 60 on both sides of the work paper 56. Each PTFE sheet 58 constitutes a clamping surface.

  Next, as shown in FIG. 6, a predetermined press pressure and heating temperature are applied between the pressure plates 54a and 54b. For this reason, first, the first gas impermeable sheet 44a (second gas impermeable sheet 44b) is pressurized and compressed, and is electrically conductive by the first gas impermeable sheet 44a (second gas impermeable sheet 44b). The outer peripheral part of the porous porous sheet 50 is pressed and deformed. Further, the entire conductive porous sheet 50 is pressurized and compressed between the pressure plates 54a and 54b.

  Accordingly, the central portion of the conductive porous sheet 50 is compressed to a predetermined thickness, while the outer peripheral portion is thinned, and the first gas impermeable sheet 44a (second gas impermeable sheet 44b) is formed on the outer peripheral portion. Be joined. Thus, the first gas diffusion layer 40b in which the first gas impermeability processing unit 40bs is provided on the outer peripheral portion and the first gas impervious sheet 44a is joined to the first gas impermeability processing unit 40bs is obtained. Similarly, the second gas diffusion layer 42b in which the second gas impermeable processing portion 42bs is provided on the outer peripheral portion and the second gas impermeable processing portion 42bs is joined to the second gas impermeable processing portion 42bs is obtained.

  On the other hand, the first electrode catalyst layer 40a is formed on the surface 38a of the solid polymer electrolyte membrane 38, and the second electrode catalyst layer 42a is formed on the surface 38b. Specifically, the first electrode catalyst layer 40a is prepared by, for example, preparing a catalyst paste in which a platinum catalyst and an ion conductive polymer solution are mixed, applying the catalyst paste on a PTFE sheet, and then performing a heat treatment. It is produced by. Moreover, the 2nd electrode catalyst layer 42a is produced on a PTFE sheet similarly to said 1st electrode catalyst layer 40a.

  Further, the first electrode catalyst layer 40a is transferred to the surface 38a of the solid polymer electrolyte membrane 38, and the second electrode catalyst layer 42a is transferred to the surface 38b, whereby a membrane electrode member is obtained. The transfer can be performed by a decal method. The first gas diffusion layer 40b is disposed on the first electrode catalyst layer 40a, while the second gas diffusion layer 42b is disposed on the second electrode catalyst layer 42a. By applying a predetermined temperature and surface pressure, these are thermocompression bonded and integrated to obtain the electrolyte membrane / electrode structure 12.

  The electrolyte membrane / electrode structure 12 is sandwiched between the anode-side separator 14 and the cathode-side separator 16, and a tightening load is applied in the stacking direction, whereby the fuel cell 10 is configured.

  The operation of the fuel cell 10 configured as described above will be described below.

  As shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 18a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 20a. Further, a cooling medium such as pure water or ethylene glycol is supplied to the cooling medium inlet communication hole 22a.

  The oxidant gas is introduced into the oxidant gas flow path 30 of the cathode-side separator 16 from the oxidant gas inlet communication hole 18a. The oxidant gas flows in the direction of arrow B along the oxidant gas flow path 30 and moves along the cathode electrode 42 of the electrolyte membrane / electrode structure 12.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 24 of the anode side separator 14 from the fuel gas inlet communication hole 20a. In the fuel gas channel 24, the fuel gas flows in the direction of arrow B, and moves along the anode electrode 40 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode electrode 42 and the fuel gas supplied to the anode electrode 40 are within the second electrode catalyst layer 42a and the first electrode catalyst layer 40a. It is consumed by the electrochemical reaction and power is generated.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 42 is discharged to the oxidant gas outlet communication hole 18b. Similarly, the fuel gas consumed by being supplied to the anode electrode 40 is discharged to the fuel gas outlet communication hole 20b.

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 22a is introduced into the cooling medium flow path 32 formed between the anode separator 14 and the cathode separator 16 adjacent to each other. In the cooling medium flow path 32, the cooling medium moves in the direction of gravity (arrow C direction). Therefore, the cooling medium is cooled over the entire power generation surface of the electrolyte membrane / electrode structure 12 and then discharged to the cooling medium outlet communication hole 22b.

  In this case, in the first embodiment, the first gas diffusion layer 40b and the second gas diffusion layer 42b are configured by the conductive porous sheet 50 in which a paste containing a carbon material and a non-hydrophilic resin is formed in a sheet shape. Has been. That is, it is composed of a microporous layer (MPL). Therefore, unlike the gas diffusion layer made of carbon paper, the carbon fiber at the end portion does not pierce the solid polymer electrolyte membrane 38, and the solid polymer electrolyte membrane 38 can be well protected. .

  Furthermore, a thin wall portion whose gas permeability is reduced by pressing is formed on the outer peripheral portion of the conductive porous sheet 50, and the thin wall portion is formed by the first gas impermeable processing portion 40bs and the second gas impermeable processing portion. 42bs is configured. The first gas impermeable sheet 44a and the second gas impermeable sheet 44b are press-bonded to the first gas impermeable processing section 40bs and the second gas impermeable processing section 42bs.

  Therefore, the first gas diffusion layer 40b can be provided with a gas impermeable function by the first gas impermeable processing section 40bs and the first gas impermeable sheet 44a. Similarly, the 2nd gas diffusion layer 42b can be provided with the gas impermeable function by the 2nd gas impermeable process part 42bs and the 2nd gas impermeable sheet | seat 44b. Thereby, the effect that it becomes possible to suppress the gas permeation from the outer peripheral part of the 1st gas diffusion layer 40b and the 2nd gas diffusion layer 42b as much as possible with a simple structure and process is acquired.

  FIG. 7 and subsequent figures are explanatory diagrams of the manufacturing method according to the second embodiment of the present invention. Note that the second embodiment may be applied to the same fuel cell 10 as in the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, as shown in FIG. 7, on the conductive porous sheet 50, a frame-shaped press sheet 62 corresponding to the first gas impermeable sheet 44a and the second gas impermeable sheet 44b is placed and mounted. The body 64 is obtained. The pressing sheet 62 is formed of, for example, glass cloth or polyimide so as not to be joined to the conductive porous sheet 50.

  Next, as shown in FIG. 8, the mounting body 64 is applied with a predetermined press pressure and heating temperature between the pressure plates 54a and 54b while being sandwiched between the pressure plates 54a and 54b (FIG. 8). 9). For this reason, the pressing sheet 62 is pressed and compressed, and the outer peripheral portion of the conductive porous sheet 50 is pressed and deformed by the pressing sheet 62. Further, the entire conductive porous sheet 50 is pressurized and compressed between the pressure plates 54a and 54b.

  Therefore, when the pressing sheet 62 is peeled off, the first gas diffusion layer 40b in which the first gas impervious treatment portion 40bs is provided on the outer peripheral portion is obtained. Similarly, the 2nd gas diffusion layer 42b by which the 2nd gas impermeable process part 42bs was provided in the outer peripheral part is obtained. As shown in FIG. 10, the first gas impermeable sheet 44a is placed on the first gas impermeable processing section 40bs to obtain a mounting body 66a, while the second gas impermeable processing section 42bs receives the second gas impermeable processing section 40bs. The transmissive sheet 44b is placed, and the placement body 66b is obtained.

  Therefore, as shown in FIG. 11, the mounting bodies 66a and 66b are sandwiched between the pressure plates 54a and 54b. In this state, as shown in FIG. 12, a predetermined pressing pressure and heating temperature are applied between the pressure plates 54a and 54b that sandwich the mounting bodies 66a and 66b. Thus, the first gas impermeable sheet 44a (second gas impermeable sheet 44b) is pressurized and compressed, and the first gas impermeable sheet 44a (second gas impermeable sheet 44b) is Press-bonded to the gas impermeable processing unit 40bs (second gas impermeable processing unit 42bs). The first gas impermeable sheet 44a (second gas impermeable sheet 44b) may be joined to the first gas impermeable processing section 40bs (second gas impermeable processing section 42bs) with an adhesive.

  For this reason, the first gas diffusion layer 40b in which the first gas impermeability processing unit 40bs is provided on the outer peripheral portion and the first gas impermeability processing unit 40bs is joined to the first gas impervious sheet 44a is obtained. Similarly, the second gas diffusion layer 42b in which the second gas impermeable processing portion 42bs is provided on the outer peripheral portion and the second gas impermeable processing portion 42bs is joined to the second gas impermeable processing portion 42bs is obtained.

  Further, a membrane electrode member in which the first electrode catalyst layer 40a and the second electrode catalyst layer 42a are transferred to the solid polymer electrolyte membrane 38 is manufactured. The first gas diffusion layer 40b is disposed on the first electrode catalyst layer 40a, while the second gas diffusion layer 42b is disposed on the second electrode catalyst layer 42a. By applying a predetermined temperature and surface pressure, these are thermocompression bonded and integrated to obtain the electrolyte membrane / electrode structure 12.

  As described above, in the second embodiment, gas permeation from the outer peripheral portions of the first gas diffusion layer 40b and the second gas diffusion layer 42b can be suppressed as much as possible with a simple configuration and process. The same effects as those of the first embodiment are obtained.

  FIG. 13 is an explanatory cross-sectional view of a fuel cell 80 according to the third embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the fourth embodiment described below, detailed description thereof is omitted.

  The electrolyte membrane / electrode structure 82 constituting the fuel cell 80 is formed by pressing the first gas diffusion layer 40b and the second gas diffusion layer 42b on the outer periphery of the first gas diffusion layer 40b and the second gas diffusion layer 42b by pressing. A gas impermeability processing unit 42bs1 is formed. As for the 1st gas impermeable process part 40bs1 and the 2nd gas impermeable process part 42bs1, the side contact | abutted to the solid polymer electrolyte membrane 38 comprises a recessed part.

  The first gas impermeable sheet 44a1 and the second gas impermeable sheet 44b1 are joined to the first gas impermeable processing section 40bs1 and the second gas impermeable processing section 42bs1 in contact with the solid polymer electrolyte membrane 38.

  In the fuel cell 80 configured as described above, gas permeation from the outer peripheral portions of the first gas diffusion layer 40b and the second gas diffusion layer 42b can be suppressed as much as possible with a simple configuration and process. The same effects as those of the first and second embodiments are obtained.

  FIG. 14 is an explanatory cross-sectional view of a fuel cell 90 according to the fourth embodiment of the present invention.

  The electrolyte membrane / electrode structure 92 constituting the fuel cell 90 is formed by pressing the first gas diffusion layer 40b and the second gas diffusion layer 42b on the outer periphery of the first gas diffusion layer 40b and the second gas diffusion layer 42b by pressing. A gas impermeability processing unit 42bs2 is formed. The first gas impermeable processing unit 40bs2 and the second gas impermeable processing unit 42bs2 have recesses on both sides of the solid polymer electrolyte membrane 38 and the separator side.

  A first gas impermeable sheet 44a2 that contacts the anode separator 14 and a first gas impermeable sheet 44a3 that contacts the solid polymer electrolyte membrane 38 are joined to both sides of the first gas impermeable processing section 40bs2. A second gas impermeable sheet 44b2 that contacts the cathode separator 16 and a second gas impermeable sheet 44b3 that contacts the solid polymer electrolyte membrane 38 are joined to both sides of the second gas impermeable processing section 42bs2.

  In the fuel cell 90 configured as described above, gas permeation from the outer peripheral portions of the first gas diffusion layer 40b and the second gas diffusion layer 42b can be suppressed as much as possible with a simple configuration and process. The same effects as those of the first to third embodiments are obtained. The fuel cells 80 and 90 can be manufactured by the manufacturing method of the first embodiment, and can also be manufactured by the manufacturing method of the second embodiment.

DESCRIPTION OF SYMBOLS 10, 80, 90 ... Fuel cell 12, 82, 92 ... Electrolyte membrane and electrode structure 14, 16 ... Separator 18a ... Oxidant gas inlet communication hole 18b ... Oxidant gas outlet communication hole 20a ... Fuel gas inlet communication hole 20b ... Fuel gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication hole 24 ... Fuel gas flow path 30 ... Oxidant gas flow path 32 ... Cooling medium flow path 38 ... Solid polymer electrolyte membrane 40 ... Anode electrode 40a 42a ... Electrode catalyst layer 40b, 42b ... Gas diffusion layer 40bs, 40bs1, 40bs2, 42bs, 42bs1, 42bs2 ... Gas impervious treatment part 42 ... Cathode electrodes 44a, 44a1, 44a2, 44a3, 44b, 44b1, 44b2, 44b3 ... Gas impervious sheet 50 ... conductive porous sheet

Claims (6)

A fuel cell in which an electrolyte membrane / electrode structure in which electrodes having an electrode catalyst layer and a gas diffusion layer are provided on both sides of a solid polymer electrolyte membrane, and a separator are laminated,
The gas diffusion layer is composed of a porous sheet in which a paste containing a carbon material and a non-hydrophilic resin is formed into a sheet shape,
A fuel cell characterized in that a thin portion thinner than a central portion is formed on the outer peripheral portion of the porous sheet by pressing, and a gas-impermeable sheet is joined to the thin portion.   2. The fuel cell according to claim 1, wherein the gas impermeable sheet is bonded to at least one of the surface on the electrode catalyst layer side and the surface on the separator side in the thin portion. . An electrolyte membrane / electrode structure in which electrodes having an electrode catalyst layer and a gas diffusion layer are provided on both surfaces of a solid polymer electrolyte membrane, and a separator, and a fuel cell manufacturing method,
Forming a porous sheet as the gas diffusion layer by forming a paste containing a carbon material and a non-hydrophilic resin into a sheet shape;
A step of providing a thin portion thinner than the central portion on the outer peripheral portion of the porous sheet, and joining a gas-impermeable sheet to the thin portion;
A method for producing a fuel cell, comprising:   The manufacturing method according to claim 3, wherein the thin-walled portion is provided on the outer peripheral portion of the porous sheet by performing a press treatment in a state where the gas-impermeable sheet is disposed on the outer peripheral portion of the porous sheet, and A method for producing a fuel cell, comprising press bonding the gas impermeable sheet. In the manufacturing method according to claim 3, the step of providing the thin-walled portion by performing a press treatment on the outer peripheral portion of the porous sheet;
Bonding the gas impermeable sheet to the thin portion;
A method for producing a fuel cell, comprising:   In the manufacturing method according to any one of claims 3 to 5, the gas impermeable sheet is bonded to at least one of the surface on the electrode catalyst layer side or the surface on the separator side in the thin portion. A method for producing a fuel cell.

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