JP5403491B2 - Membrane electrode assembly and manufacturing method thereof - Google Patents

Description

  The present invention relates to a membrane electrode assembly used as a power generation element of a polymer electrolyte fuel cell and a method for producing the same.

  There are various types of fuel cells. Among them, polymer electrolyte fuel cells can be started at room temperature, have few problems of electrolyte dissipation, and have a high current density. As a battery element of this polymer electrolyte fuel cell, a membrane electrode assembly (MEA) comprising an electrolyte membrane sandwiched between electrode layers on the anode side and the cathode side is used.

  The membrane electrode assembly includes a pair of electrode catalyst layers that sandwich an electrolyte membrane, and a pair of gas diffusion layers that sandwich the pair of electrode catalyst layers. The gas diffusion layer is a water repellent layer and a gas diffusion base material. The water repellent layer is disposed between the electrode catalyst layer and the gas diffusion base material, thereby suppressing and preventing water condensation in the gas diffusion layer (see Patent Document 1). .

  The membrane electrode assembly as described above is provided with an anode-side and cathode-side gas seal material on the outer periphery thereof, and then a fuel cell is formed by alternately laminating with separators. At this time, the membrane electrode assembly is handled as a membrane electrode assembly with a gas seal material, but there is nothing to support the electrolyte membrane in the portion between the electrode and the gas seal material. There is a risk of damaging the electrolyte membrane.

  Therefore, in the conventional membrane electrode assembly, a protective film is arranged on both sides of the outer periphery of the electrolyte membrane, and the outer periphery of the electrolyte membrane and the protective film are sandwiched by the gas seal material, so that the portion near the gas seal material Some of the electrolyte membranes have increased mechanical strength (see Patent Document 2).

JP 2007-165025 A Japanese Patent No. 3368907

  However, in the conventional membrane electrode assembly as described above, since the protective film disposed on both sides of the electrolyte membrane is adopted as an additional component, there is a problem in that the manufacturing man-hour and cost increase accordingly. There was a problem to solve such problems.

  The present invention has been made paying attention to the above-described conventional problems, and in a membrane electrode assembly in which a gas seal material is arranged on the outer periphery, an electrolyte membrane in the vicinity of the gas seal material using existing components It is an object of the present invention to provide a membrane electrode assembly and a method for manufacturing the same, which can protect the substrate and realize reduction in manufacturing steps and costs.

The membrane electrode assembly of the present invention has an electrode catalyst layer and a water repellent layer laminated on each of the anode side and cathode side of the electrolyte membrane, and gas seals on the anode side and cathode side along the outer periphery thereof. The material is arranged. In the membrane electrode assembly, the anode side and cathode side gas seal materials are formed by bending at least one seal material , and at least the outer periphery of the electrolyte membrane and the water repellent layer is formed on the anode side and the cathode side. The structure is sandwiched between the gas seal members on the side, and the above structure is used as means for solving the conventional problems.

  The method for producing a membrane / electrode assembly of the present invention is characterized in that, when the membrane / electrode assembly is produced, the water-repellent layer and the electrode catalyst layer are joined after forming the water-repellent layer on the molding substrate. More preferably, the electrode catalyst layer is preliminarily formed on the electrolyte membrane.

The membrane electrode assembly of the present invention protects the electrolyte membrane in the vicinity of the gas seal material by using a part of the water repellent layer, which is an existing component, in the membrane electrode assembly in which the gas seal material is arranged on the outer periphery. It is possible to reduce the number of manufacturing steps and costs.
In addition, the membrane electrode assembly described above can easily align the gas seal material on the anode side and the cathode side, and can contribute to further improvement in production efficiency and further reduction in manufacturing man-hours and costs. In the portion where the bent portion of the seal material is present, leakage of the reaction gas from the central power generation region to the outside is completely prevented, so that the reliability of the fuel cell can be further improved.

  The method for producing a membrane electrode assembly of the present invention forms a water-repellent layer on a molding substrate, so that the heating temperature of the water-repellent layer can be increased, thereby strengthening the water-repellent layer. The electrolyte membrane can be reliably protected and can contribute to the reduction of manufacturing steps and costs.

The top view (a) explaining one Embodiment of the membrane electrode assembly concerning this invention, sectional drawing (b) based on the AA line in FIG. A, and sectional drawing based on the BB line in FIG. (C). It is a figure which shows one Embodiment of the manufacturing method of the membrane electrode assembly concerning this invention, Comprising: It is each sectional drawing (a)-(c) explaining the manufacturing process. It is a figure which shows other embodiment of the manufacturing method of the membrane electrode assembly concerning this invention, Comprising: It is each sectional drawing (a)-(e) explaining the manufacturing process. It is a figure which shows other embodiment of the manufacturing method of the membrane electrode assembly concerning this invention, Comprising: It is each sectional drawing (a) and (b) explaining the manufacturing process. The top view explaining other embodiment of the membrane electrode assembly concerning this invention (a), sectional drawing (b) based on the CC line in FIG. A, and the cross section based on the DD line in FIG. It is a figure (c). The top view explaining other embodiment of the membrane electrode assembly concerning this invention (a), sectional drawing based on the EE line in FIG. A (b), and the cross section based on the FF line in FIG. It is a figure (c).

  Hereinafter, embodiments of a membrane electrode assembly and a method for manufacturing the same according to the present invention will be described with reference to the drawings.

  A membrane / electrode assembly M1 shown in FIG. 1 includes electrode catalyst layers 11 and 12 and water-repellent layers 21 and 22 in a laminated state on each surface of the electrolyte membrane 1 on the anode side and the cathode side. Gas diffusion layers 31 and 32 are provided outside the water repellent layers 21 and 22. The membrane electrode assembly M1 includes gas seal materials 41 and 42 on the anode side and the cathode side along the outer periphery of each layer. The membrane electrode assembly M1 has a configuration in which the outer peripheral portions of the electrolyte membrane 1 and the water repellent layers 21 and 22 are sandwiched between the gas seal materials 41 and 42. For this reason, the membrane electrode assembly M1 can also be said to be a membrane electrode assembly with a gas sealant.

  In the membrane electrode assembly M1 of this embodiment, the water repellent layers 21 and 22 are slightly larger than the electrode catalyst layers 11 and 12 and the gas diffusion layers 31 and 32, and the electrolyte membrane 1 is one larger than the water repellent layers 21 and 22. It is a big thing around. The range where all the layers are polymerized is the power generation region. The electrolyte membrane 1 and the water-repellent layers 21 and 22 have an outer peripheral portion extending outward with respect to the power generation region, and the outer peripheral portion is sandwiched between the gas seal materials 41 and 42.

  The gas seal materials 41 and 42 of this embodiment have a rectangular shape including the above-described power generation region in the center, and have a central opening Hc that exposes the power generation region. Three parts Hm are provided.

  These openings Hm communicate with each other together with the similar openings of the separator when the membrane electrode assembly M1 and separators (not shown) are alternately stacked in multiple stages to constitute a fuel cell. Form a road. That is, a fuel gas supply path and discharge path, an oxidant gas (air) supply path and discharge path, a refrigerant flow path, and the like are formed, and the fuel gas is circulated to the anode side of the membrane electrode assembly M1, An oxidant gas is circulated on the cathode side.

  Here, the material of the polymer electrolyte membrane 1 is not particularly limited, and a known material can be used, but any material having at least high proton conductivity may be used. At this time, the polymer electrolyte is roughly classified into a fluorine-based electrolyte containing a fluorine atom in the whole or a part of the polymer skeleton and a hydrocarbon electrolyte not containing a fluorine atom in the polymer skeleton.

  Specific examples of fluorine-based electrolytes include perfluorocarbon sulfonates such as Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Co., Ltd.), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), etc. Polymer, polytrifluorostyrene sulfonic acid polymer, perfluorocarbon phosphonic acid polymer, trifluorostyrene sulfonic acid polymer, ethylene tetrafluoroethylene-g-styrene sulfonic acid polymer, ethylene-tetrafluoroethylene Preferred examples include polymers and polyvinylidene fluoride-perfluorocarbon sulfonic acid polymers.

  Specific examples of the hydrocarbon electrolyte include polysulfone sulfonic acid, polyaryl ether ketone sulfonic acid, polybenzimidazole alkyl sulfonic acid, polybenzimidazole alkyl phosphonic acid, polystyrene sulfonic acid, polyether ether ketone sulfonic acid, polyphenyl. A sulfonic acid etc. are mentioned as a suitable example.

  The anode side electrode catalyst layer 11 and the cathode side electrode catalyst layer 12 contain an electrode catalyst and a proton conductive polymer, and if necessary, contain a water repellent material. The electrode catalyst is formed by supporting a catalyst component on a conductive material. The proton conductive polymer in the electrode catalyst layers 11 and 12 is not particularly limited, and a known one can be used, but the same materials as those used for the polymer electrolyte membrane 1 can be used, and at least high protons can be used. Any material having conductivity may be used.

  The catalyst component used for the electrode catalyst layers 11 and 12 is not particularly limited as long as it has a catalytic action on the oxygen reduction reaction in the cathode side electrode catalyst layer 12, and a known catalyst can be used. The catalyst component used in the anode-side electrode catalyst layer 11 is not particularly limited as long as it has a catalytic action for the oxidation reaction of hydrogen, and a known catalyst can be used in the same manner. Specifically, selected from platinum, ruthenium, iridium, rhodium, palladium, osmium, tungsten, lead, iron, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium, aluminum, and alloys thereof, and the like Is done. Among these, those containing at least platinum are preferably used in order to improve catalyst activity, poisoning resistance to carbon monoxide and the like, heat resistance, and the like. Furthermore, the shape and size of the catalyst component are not particularly limited, and the same shape and size as known catalyst components can be used, but the catalyst component is preferably granular.

  Any conductive material may be used as long as it has a specific surface area for supporting the catalyst component in a desired dispersed state and has sufficient electronic conductivity as a current collector. The main component is carbon. Is preferred. Specific examples include carbon particles made of carbon black, activated carbon, coke, natural graphite, artificial graphite and the like. Further, as such carbon materials, more specifically, acetylene black, Vulcan, Ketjen black, black pearl, graphitized acetylene black, graphitized Vulcan, graphitized Ketjen black, graphitized carbon, graphitized black pearl , Carbon nanotubes, carbon nanofibers, carbon nanohorns, and carbon fibrils as main components. “The main component is carbon” means that the main component contains carbon atoms, and is a concept that includes both carbon atoms and substantially carbon atoms. In some cases, elements other than carbon atoms may be included in order to improve the characteristics of the fuel cell. In addition, being substantially composed of carbon atoms means that mixing of impurities of about 2 to 3% by mass or less is allowed.

  The water repellent layers 21 and 22 are made of a conductive material and a binder material, and the material is not particularly limited, and a known material can be used. As the conductive material, the same material as the catalyst layer can be used. Binder materials include fluororesins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and polyolefins such as polypropylene and polyethylene. Examples thereof include rubbers such as resin, silicone, NBR, and SBR. Among these, PTFE is more preferably used because of excellent water repellency and corrosion resistance during electrode reaction.

   The material of the gas diffusion layers 31 and 32 is not particularly limited, and a known material can be used, but a sheet-like material made of carbon paper, nonwoven fabric, carbon fabric, paper-like paper body, felt or the like, Metal porous bodies and fabrics made of stainless steel, titanium and the like. When the gas diffusion layers 31 and 32 have excellent electron conductivity, efficient transport of electrons generated by the power generation reaction is achieved, and the performance of the fuel cell is improved. Further, when the gas diffusion layers 31 and 32 have excellent water repellency, the generated water is discharged more efficiently.

  The gas seal materials 41 and 42 are not particularly limited, and any known material can be used as long as it is impermeable to fuel gas or oxidant gas. Examples include phthalate (PEN), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF). In order to improve the adhesion of the gas seal materials 41 and 42, an adhesive layer such as a thermoplastic resin may be provided therebetween.

  The membrane electrode assembly M1 according to this embodiment has an additional component such as a conventional protective layer by the configuration in which the outer peripheral portions of the electrolyte membrane 1 and the water-repellent layers 21 and 22 are sandwiched between the gas seal materials 41 and 42. Even if not used, it is possible to prevent a situation in which the edges of the gas diffusion layers 31 and 32 and the edges of the gas seal materials 41 and 42 damage the electrolyte membrane 1. That is, the electrolyte membrane 1 in the vicinity of the gas seal materials 41 and 42 can be protected by using a part of the water-repellent layers 31 and 32 which are existing components, and both cost reduction and high durability are achieved. be able to.

  In addition, the membrane electrode assembly M1 has a function of the water repellent layers 21 and 22, that is, a function of suppressing / preventing water condensation in the gas diffusion layers 31 and 32, and realizes reduction in manufacturing man-hours and costs. be able to.

  Further, in the membrane electrode assembly M1 of this embodiment, as shown in FIG. 1B, the outer peripheral ends of the electrolyte membrane 1 and the water-repellent layers 11 and 12 are inside the outer peripheral ends of the gas seal materials 41 and 42. (Left side in the figure). Thereby, the leakage of the reaction gas from the outer peripheral ends of the electrolyte membrane 1 and the water repellent layers 11 and 12 to the outside can be reliably prevented, and the reliability of the fuel cell can be further improved.

  Further, in the membrane electrode assembly M1 of this embodiment, as shown in FIG. 1 (c), the gas seal materials 41 and 42 have an opening Hm for reaction gas circulation, and the electrolyte membrane 1 and the repellent material are repelled. The outer peripheral ends of the water layers 11 and 12 are arranged on the inner side (left side in the drawing) than the opening Hm of the gas seal materials 41 and 42. Thereby, the leakage of the reaction gas from the outer peripheral ends of the electrolyte membrane 1 and the water-repellent layers 11 and 12 to the opening Hm can be reliably prevented, and the reliability of the fuel cell can be further improved.

  Further, in the membrane electrode assembly M1 of this embodiment, as shown in FIGS. 1B and 1C, the outer peripheral end of the electrolyte membrane 1 is outside the outer peripheral ends of the water-repellent layers 11 and 12 (in the drawing). On the right). As a result, the outer peripheral ends of the anode-side and cathode-side water-repellent layers 11 and 12 are reliably cut off from the outside, and the reaction gas on the anode-side and cathode-side leaks or electricity is short-circuited beforehand. In this way, the reliability of the fuel cell can be further increased.

Said membrane electrode assembly M1 can be obtained with the manufacturing method shown in FIGS.
The membrane electrode assembly manufacturing method shown in FIG. 2 uses molding substrates 51 and 52 made of a heat-resistant release tape or the like, and after forming the water-repellent layers 21 and 22 on the molding substrates 51 and 52. The water repellent layers 21 and 22 and the electrode catalyst layers 11 and 21 are joined.

  That is, as shown in FIG. 2A, the water-repellent layers 21 and 22 are formed on the anode-side and cathode-side molding substrates 51 and 52, respectively. Specifically, for example, a paste-like water-repellent layer material is applied onto the molding substrates 51 and 52, and this is heated and pressurized to form film-like sheets, which are respectively formed as the water-repellent layers 21 and 22.

  Thereafter, as shown in FIG. 2B, the water-repellent layers 21 and 22 and the electrode catalyst layers 11 and 12 are bonded to each other by pressurization and heating. In this case, the respective electrode catalyst layers 11 and 12 are formed in advance on the electrolyte membrane 1, and the forming substrates 51 and 52 and the water repellent layers 21 and 22, and the electrolyte membrane 1 and the electrode catalyst layers 11 and 12 are respectively formed. You may make it join. Then, as shown in FIG. 2C, the respective molding substrates 51 and 52 are peeled and removed.

  In the manufacturing method of the membrane electrode assembly described above, since the water-repellent layers 21 and 22 are formed in advance on the molding substrates 51 and 52, at this stage, the heat-resistant temperature of the electrolyte membrane 1 is not restricted at all. The heating temperature and pressurizing pressure of the water layers 21 and 22 can be increased. As a result, the structure of the water repellent layers 21 and 22 is strengthened, and the electrolyte membrane 1 can be more reliably protected. Moreover, if the electrode catalyst layers 11 and 12 are formed in advance on the electrolyte membrane 1, a transfer substrate for the electrode catalyst layer is not necessary, which can contribute to further reduction in manufacturing steps and costs.

  The membrane electrode assembly shown in FIG. 3 is manufactured using the anode-side and cathode-side molding substrates 51 and 52, and after forming the water-repellent layers 21 and 22 on the molding substrates 51 and 52, respectively. Electrode catalyst layers 11 and 12 are formed on the water-repellent layers 21 and 22, respectively, and then the electrode catalyst layers 11 and 12 and the electrolyte membrane 1 are joined.

  That is, like the manufacturing method shown in FIG. 2, after forming the water repellent layers 21 and 22 on the respective molding substrates 51 and 52, as shown in FIG. 3A, the electrocatalyst ink In is applied by the spray Sp. As shown in FIG. 3B, the electrode catalyst layer 11 (12) is formed by spraying and coating.

  Thereafter, as shown in FIGS. 3C and 3D, the electrode catalyst layers 11 and 12 and the electrolyte membrane 1 are bonded to each other with the electrolyte membrane 1 sandwiched between the anode-side and cathode-side laminates, and finally, As shown in FIG. 3E, the respective molding substrates 51 and 52 are peeled and removed.

  In the manufacturing method of the membrane electrode assembly, the water-repellent layers 21 and 22 having a strong structure can be obtained as in the manufacturing method shown in FIG. 2 and the water-repellent layer 21 is formed on the molding substrates 51 and 52. , 22 is formed, and the electrode catalyst layers 11 and 12 are formed on the water-repellent layers 21 and 22. Therefore, the transfer substrate for the electrode catalyst layers 11 and 12 is not necessary, and the manufacturing man-hours and costs can be further reduced. be able to.

  The method for manufacturing the membrane / electrode assembly shown in FIG. 4 includes the electrolyte membrane 1, the electrode catalyst layers 11 and 12, the water repellent layers 21 and 22, the gas diffusion layers 31 and 32, and the gas seal material 41 in the molds P 1 and P 2. , 42 are arranged, and these are integrated by hot pressing.

  In the method for manufacturing a membrane electrode assembly, the electrolyte membrane 1, the electrode catalyst layers 11 and 12, the water repellent layers 21 and 22, the gas diffusion layers 31 and 32, and the gas seal materials 41 and 42 are joined at the same time. As a result, it is possible to improve production efficiency and reduce manufacturing man-hours and costs.

  Further, in the above method for manufacturing a membrane / electrode assembly, the electrolyte membrane 1, the electrode catalyst layers 11, 12 and the water repellent layers 21, 22 are integrated in advance as a laminate based on the manufacturing method shown in FIGS. You can also keep it. Furthermore, a contact layer may be interposed at the joint portion of the laminate, the gas diffusion layers 31 and 32, and the gas seal materials 41 and 42.

  The basic configuration of the membrane electrode assembly M2 shown in FIG. 5 is the same as that shown in FIG. The same components as those of the previous embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The illustrated membrane electrode assembly M2 is formed by bending at least one seal material 40 by anode-side and cathode-side gas seal materials 41,.

  In this embodiment, a seal material 40 in which a central opening portion Hc on the anode side and a cathode side and an opening portion Hm for a reaction gas flow path are formed in advance is prepared, and this is folded in half to provide gas seals on the anode side and the cathode side. The materials 41 and 42 are formed. At this time, in the illustrated example, the bent portion 40a of the seal material 40 is on the long side of the gas seal materials 41 and 42 having a rectangular shape. In this way, the membrane electrode assembly M2 has a configuration in which the outer peripheral portions of the electrolyte membrane 1 and the water-repellent layers 21 and 22 are sandwiched between the gas seal materials 41 and 42.

  The membrane electrode assembly M2 having the above configuration facilitates the alignment of the anode-side and cathode-side gas seal materials 41, 42, and contributes to further improvement in production efficiency and further reduction in manufacturing man-hours and costs. Can do. Moreover, since the leakage of the reaction gas from the central power generation region to the outside is completely prevented at the portion where the bent portion 40a of the seal material 40 exists, the reliability of the fuel cell can be further improved.

  The basic structure of the membrane electrode assembly M3 shown in FIG. 6 is the same as that shown in FIG. The same components as those of the previous embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The illustrated membrane electrode assembly M3 is formed by bending at least one seal material 40 with gas seal materials 41 and 42 on the anode side and the cathode side.

  In this embodiment, a seal material 40 in which a central opening Hc on the anode side and a cathode side and an opening Hm for a reaction gas flow path are formed in advance is prepared, and this is bent at two locations and the ends are joined together. Thus, the gas seal materials 41 and 42 on the anode side and the cathode side are formed. At this time, in the illustrated example, the two bent portions 40a and 40a of the sealing material 40 are the long sides of the gas sealing materials 41 and 42 having a rectangular shape.

  Thus, the membrane electrode assembly M3 has a configuration in which the outer peripheral portions of the electrolyte membrane 1 and the water-repellent layers 21 and 22 are sandwiched between the gas seal materials 41 and 42. Further, in the membrane electrode assembly M3, as shown in FIG. 6C in particular, the joint portion 40b of the sealing material 40 is outside the outer peripheral ends of the electrolyte membrane 1 and the water repellent layer (left side in the figure). It is arranged.

  As in the previous embodiment, the membrane electrode assembly M3 having the above configuration facilitates the alignment of the gas seal materials 41 and 42 on the anode side and the cathode side, further improving the production efficiency, This can contribute to further cost reduction. Further, in the portion where the bent portions 40a, 40a of the sealing material 40 are present, the leakage of the reaction gas from the central power generation region to the outside is completely prevented, so that the reliability of the fuel cell can be further improved. .

  Furthermore, in the membrane electrode assembly M3, since the joint portion 40b of the sealing material 40 is disposed outside the outer peripheral ends of the electrolyte membrane 1 and the water repellent layer, the dimensional accuracy of each member is temporarily lowered within an allowable range. Even when set, the junction 40b does not communicate with the outer peripheral ends of the electrolyte membrane 1 and the water-repellent layers 21 and 22, and the leakage of the reaction gas is more reliably prevented, thereby improving the reliability of the fuel cell. be able to. In addition, you may fill the clearance gap between the junction parts 40b with the adhesive agent used when joining the membrane electrode assembly M3 and a separator.

  In addition, the structure of the membrane electrode assembly and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments, and details of the structure can be appropriately changed without departing from the gist of the present invention. . For example, it is possible to adopt a configuration in which three or more outer peripheral portions including the electrolyte membrane and the water repellent layer are sandwiched by a gas seal material. In particular, in the embodiment shown in FIGS. 5 and 6, a plurality of seal materials are prepared, and these are bent in an appropriate direction and number of times to form the anode side and cathode side gas seal materials. Is also possible.

DESCRIPTION OF SYMBOLS 1 Electrolyte membrane 11 12 Electrode catalyst layer 21 22 Water-repellent layer 31 32 Gas diffusion layer 41 42 Gas seal material 40 Seal material 40b Joint part (sealing material) 51 52 Molding substrate Hm (For reaction gas circulation) Opening P1 P2 Mold M1 Membrane / electrode assembly M2 Membrane / electrode assembly M3 Membrane / electrode assembly

Claims (11)

A membrane electrode assembly in which an electrode catalyst layer and a water repellent layer are laminated on each surface of the electrolyte membrane on the anode side and cathode side, and gas seal materials on the anode side and cathode side are disposed along the outer periphery thereof. The anode-side and cathode-side gas seal materials are formed by bending at least one seal material , and at least the outer periphery of the electrolyte membrane and the water-repellent layer is formed on the anode-side and cathode-side gas seal materials. A membrane electrode assembly, characterized by being sandwiched between.   The membrane electrode assembly according to claim 1, wherein the outer peripheral ends of the electrolyte membrane and the water-repellent layer are disposed inside the outer peripheral end of the gas seal material.   The gas seal material has an opening for circulating a reaction gas, and the outer peripheral ends of the electrolyte membrane and the water-repellent layer are arranged inside the opening of the gas seal material. 2. The membrane electrode assembly according to 2.   The membrane electrode assembly according to any one of claims 1 to 3, wherein the outer peripheral end of the electrolyte membrane is disposed outside the outer peripheral end of the water repellent layer.   The membrane electrode assembly according to any one of claims 1 to 4, wherein the gas sealing material on the anode side and the cathode side is formed by folding a single sealing material in half.   5. The gas seal material on the anode side and the cathode side is formed by bending one seal material at two locations and joining the end portions to each other. Membrane electrode assembly.   7. The membrane electrode assembly according to claim 6, wherein the joint portion of the sealing material is disposed outside the outer peripheral ends of the electrolyte membrane and the water repellent layer. In manufacturing the membrane electrode assembly according to any one of claims 1 to 7,
A method for producing a membrane / electrode assembly, comprising forming a water-repellent layer on a molding substrate and then joining the water-repellent layer and the electrode catalyst layer.   The method for producing a membrane electrode assembly according to claim 8, wherein the electrode catalyst layer is formed in advance on the electrolyte membrane. In manufacturing the membrane electrode assembly according to any one of claims 1 to 7,
A method for producing a membrane / electrode assembly, comprising: forming a water-repellent layer on a molding substrate; then forming an electrode catalyst layer on the water-repellent layer; and then joining the electrode catalyst layer and the electrolyte membrane.   The membrane electrode assembly according to any one of claims 8 to 10, wherein an electrolyte membrane, an electrode catalyst layer, a water repellent layer, and a gas seal material are disposed in a mold, and then integrated by hot pressing. Production method.

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