JP6115414B2 - Membrane electrode structure and method for producing membrane electrode structure - Google Patents

Description

  The present invention relates to a membrane electrode structure in a polymer electrolyte fuel cell and a method for producing the membrane electrode structure.

  A fuel cell that reacts a fuel such as hydrogen with an oxidant such as oxygen and directly converts the resulting chemical energy into electrical energy, depending on the type of electrolyte used, alkaline, phosphoric acid, solid polymer, molten It is classified into carbonate form and solid oxide form. The polymer polymer fuel cell (PEFC) has a shorter start-up time than other fuel cells, and can operate in a low-temperature environment, has a high output density, and can be downsized. Since it can be reduced in weight, it is expected to be applied as a portable power source, a household power source, and an in-vehicle power source.

  A polymer electrolyte fuel cell includes a membrane electrode assembly (MEA) having a structure in which a membrane electrode assembly in which a pair of catalyst layers are stacked on both surfaces of an electrolyte membrane is sandwiched between gas diffusion layers, and a pair of membrane electrode assemblies (MEA). It is sandwiched between separators. One separator has a gas flow path for supplying a fuel gas containing hydrogen to one catalyst layer of the membrane electrode structure, and the other separator is an oxidant gas containing oxygen in the other catalyst layer A gas flow path for supplying is formed. A structure in which this membrane electrode structure is sandwiched between a pair of separators is called a unit cell (cell), and is a unit constituting a fuel cell.

  The membrane electrode structure may include a gasket. Gaskets constituting a part of the membrane electrode structure are required to support the electrolyte membrane and to contribute to the suppression of oxygen leak and hydrogen leak and the maintenance of the humidity of the electrolyte membrane. From the viewpoint of process cost, a membrane electrode structure with a small number of parts and easy assembly is desired, and a membrane electrode structure that can be produced by lamination is advantageous in manufacturing.

  A polymer electrolyte fuel cell is used by stacking a plurality of single cells (hereinafter referred to as “stack”) for the purpose of increasing output density and making the entire fuel cell compact. The number of stacks varies depending on the power required. For portable power sources of general portable electric devices, several to about 10 sheets, for cogeneration stationary electric and hot water supply machines, about 60 to 90 sheets, and for automobile applications, 250 sheets. From about 400 to 400. In order to increase the output, it is necessary to increase the number of stacks, so the cost of the single cell (cell) greatly affects the cost of the entire fuel cell. From the viewpoint of process cost, it is desired that the membrane electrode structure of a polymer electrolyte fuel cell has a small number of parts and can be easily assembled.

A conventional membrane electrode structure employs a structure in which the periphery of the electrolyte membrane is sealed in order to protect the electrolyte membrane and suppress oxygen leakage and hydrogen leakage (see, for example, Patent Document 1). In Patent Document 1, after the membrane electrode structure is formed, resin molding is performed using a liquid sealing material such as an elastomer by a method such as injection molding, and sealing is performed by wrapping the outer periphery of the peripheral portion of the electrolyte membrane. The technology to do is described.
Moreover, the sealing method of the peripheral part of the electrolyte membrane different from said sealing form is also known (for example, refer patent document 2). Patent Document 2 describes a technique for sealing a peripheral portion of an electrolyte membrane by forming a reinforcing sheet having a weld layer on a peripheral portion on a gasket and welding the weld layer and the membrane electrode structure. .

JP 2006-92924 A JP 2009-81118 A

However, the elastomer used for the resin mold is expensive as a gasket, and further, it is necessary to take steps such as injection molding in order to arrange the gasket so as to wrap around the peripheral portion of the electrolyte membrane. The first technique is not suitable for mass production.
Further, in the method of forming a reinforcing sheet having a welded layer on the peripheral edge on the gasket, a reinforcing sheet and a welded layer are required in addition to the gasket, and an increase in the number of parts cannot be avoided. Is disadvantageous in terms of process costs.
As described above, the sealing of the peripheral portion of the electrolyte membrane in the conventional membrane electrode structure has a problem that it has a large number of parts, is complicated to assemble, is expensive, and is not suitable for mass production. there were.
Accordingly, the present invention provides a membrane electrode structure in which the periphery of the electrolyte membrane is sealed with a small number of parts and man-hours and a method for manufacturing the membrane electrode structure in order to solve the above-described problems of the prior art The purpose is to do.

  In order to solve the above problems, a method for manufacturing a membrane electrode assembly according to one aspect of the present invention includes a first step of forming a sheet-like member formed by attaching and integrating a gasket to a gas diffusion layer, and a pair of the sheets A membrane electrode assembly having a second step of joining the sheet-like members and joining a part of the peripheral portions of the sheet-like members in the circumferential direction, and a pair of catalyst layers arranged with the electrolyte membrane sandwiched therebetween Is sandwiched between the pair of sheet-like members joined together, and the remaining circumferential portions of the two sheet-like members are joined together to seal the membrane electrode assembly in the pair of sheet-like members. And a third step of stopping.

In the method of manufacturing a membrane electrode structure, the membrane electrode assembly includes a pair of catalyst layers arranged in a portion excluding the peripheral portions on both surfaces of the electrolyte membrane, and an outer periphery of the peripheral portions of the pair of catalyst layers. On the side, a gasket for a joined body surrounding the peripheral edge portions of the pair of catalyst layers in the circumferential direction may be disposed.
In the method of manufacturing the membrane electrode structure, the gasket attached to the gas diffusion layer in the first step is a sealing gasket, and in the first step, the outer periphery of the gas diffusion layer is surrounded. After disposing the sealing gasket, an integration gasket is disposed so as to straddle the gas diffusion layer and the sealing gasket, and the gas diffusion layer and the sealing gasket are separated by the integration gasket. It may be integrated.

Further, in the method of manufacturing the membrane electrode structure, the sheet-like member has a substantially rectangular shape, and in the second step, of the sealing gasket arranged on a peripheral portion of the sheet-like member, the opposing surface Only the two sides to be joined may be joined to join the pair of sheet-like members.
In the method of manufacturing a membrane electrode structure, the sealing gasket is made of a thermoplastic resin, the integration gasket is made of a thermosetting resin, and the sealing is performed in the second step. You may weld and join only two sides which oppose among stop gaskets.
Moreover, the manufacturing method of the said membrane electrode structure may weld only two sides which oppose among the said gaskets for sealing.
Further, in the method of manufacturing the membrane electrode structure, in the third step, the portion of the sealing gasket that has not been welded in the second step is welded, so that the membrane electrode assembly is bonded to the pair of gaskets. You may seal in a sheet-like member.

The membrane electrode assembly according to one aspect of the present invention includes a membrane electrode assembly having an electrolyte membrane and a pair of catalyst layers arranged with the electrolyte membrane interposed therebetween, and a sealing covering the entire membrane electrode assembly The sealing layer includes a pair of gas diffusion layers disposed across the membrane electrode assembly, a peripheral portion of the membrane electrode assembly, and the pair of gases A sealing gasket that surrounds the peripheral edge of the diffusion layer in the circumferential direction, and an integral unit that integrates the sealing gasket and the gas diffusion layer so as to straddle the sealing gasket and the gas diffusion layer And a gasket.
In the membrane electrode assembly, the pair of catalyst layers is disposed in a portion excluding the peripheral portions on both surfaces of the electrolyte membrane, and the peripheral edges of the pair of catalyst layers are arranged on the outer peripheral side of the peripheral portions of the pair of catalyst layers. A bonded gasket that surrounds the portion in the circumferential direction may be disposed.

  According to the method for producing a membrane electrode structure of the present invention, a membrane electrode assembly and a pair of sheet-like members integrated with a gas diffusion layer and a gasket are joined in a separate process. It is possible to simplify the process for stacking the membrane electrode structures. Therefore, the manufacturing method of the membrane electrode structure of the present invention is suitable for mass production, and the membrane electrode structure can be manufactured easily and inexpensively.

Further, according to the method for manufacturing a membrane electrode structure of the present invention, the membrane electrode assembly is sandwiched between the pair of sheet-like members stacked and joined, and sealed in the pair of sheet-like members. Therefore, the peripheral portion of the exposed electrolyte membrane is sealed, and a membrane electrode structure excellent in prevention of oxygen leak and hydrogen leak can be manufactured with a small number of parts.
Furthermore, the membrane electrode structure of the present invention uses a gas diffusion layer and a sealing gasket that are integrated with an integration gasket, and the membrane electrode assembly and the gas diffusion layer are laminated and the periphery of the electrolyte membrane. Therefore, it is excellent in the prevention of oxygen leak and hydrogen leak, and the number of parts required for manufacturing is small and inexpensive.

It is a schematic sectional drawing of the unit cell of a polymer electrolyte fuel cell provided with the membrane electrode structure which concerns on one Embodiment of this invention. 1 is a schematic top view of a membrane electrode structure according to an embodiment of the present invention. It is a schematic sectional drawing of the membrane electrode structure which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the 1st process of the manufacturing method of the membrane electrode structure which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the 2nd process of the manufacturing method of the membrane electrode structure which concerns on one Embodiment of this invention. It is a schematic top view which shows the 3rd process of the manufacturing method of the membrane electrode structure which concerns on one Embodiment of this invention.

DESCRIPTION OF EMBODIMENTS Embodiments relating to a membrane electrode structure and a method for producing the membrane electrode structure of the present invention will be described in detail with reference to the drawings.
<About polymer electrolyte fuel cells>
FIG. 1 is a schematic cross-sectional view of a unit cell of a polymer electrolyte fuel cell including a membrane electrode structure according to an embodiment of the present invention.
As shown in FIG. 1, a unit cell 100 of a polymer electrolyte fuel cell includes a membrane electrode structure 20 and a pair of separators 30 that sandwich the membrane electrode structure 20.

<About membrane electrode structure>
Next, the configuration of the membrane electrode structure 20 according to the present embodiment will be described with reference to FIGS.
FIG. 2 is a schematic top view of the membrane electrode structure 20 according to the embodiment of the present invention, and FIG. 3 is a schematic cross-sectional view taken along line II of the membrane electrode structure 20 of FIG.
As shown in FIG. 3, the membrane electrode structure 20 includes a membrane electrode assembly 24 and a sealing layer 29 that is disposed outside the membrane electrode assembly 24 and covers the entire membrane electrode assembly 24.
The membrane electrode assembly 24 includes an electrolyte membrane 21, a cathode side catalyst layer 22a and an anode side catalyst layer 22b arranged with the electrolyte membrane 21 interposed therebetween, and joined body gaskets 23a and 23b.

The sealing layer 29 includes gas diffusion layers 28a and 28b, a sealing gasket 26, an integration gasket 27a disposed on the cathode side catalyst layer 22a side, and an integration disposed on the anode side catalyst layer 22b side. Gasket 27b.
The electrolyte membrane 21, the cathode side catalyst layer 22a, and the anode side catalyst layer 22b are substantially rectangular, and the width dimension and length dimension of the electrolyte membrane 21 are the width dimensions of the cathode side catalyst layer 22a and the anode side catalyst layer 22b. And larger than the length dimension.

  The cathode side catalyst layer 22a is disposed on a portion excluding the peripheral portion of one surface (the upper surface in FIG. 3) of the electrolyte membrane 21, and the anode side catalyst layer 22b is disposed on the other surface (in FIG. 3). The lower surface is disposed in the portion excluding the peripheral portion. The joined body gasket 23a is arranged on the outer peripheral side of the peripheral portion of the cathode side catalyst layer 22a so as to surround the peripheral portion of the cathode side catalyst layer 22a in the circumferential direction. That is, the bonded gasket 23a may be disposed on the surface of the electrolyte membrane 21 where the cathode catalyst layer 22a is not disposed so as to be in close contact with the peripheral edge of the cathode catalyst layer 22a. preferable.

The joined body gasket 23b is arranged on the outer peripheral side of the peripheral portion of the anode side catalyst layer 22b so as to surround the peripheral portion of the anode side catalyst layer 22b in the circumferential direction. In other words, the bonded gasket 23b may be disposed on the surface of the electrolyte membrane 21 where the anode-side catalyst layer 22b is not disposed so as to be in close contact with the peripheral portion of the anode-side catalyst layer 22b. preferable.
Since the gaskets 23a and 23b for the joined body are stronger than the electrolyte membrane 21, the membrane electrode assembly 24 is drawn when the membrane electrode assembly 24 is pulled between a pair of sheet-like members described later by the above configuration. Can be easily pulled in without bending. Therefore, the membrane electrode structure 20 can be manufactured easily.

The sealing gasket 26 is disposed so as to surround the peripheral edge of the membrane electrode assembly 24 and the peripheral edges of the gas diffusion layers 28a and 28b in the circumferential direction. At this time, it is preferable that the peripheral portions of the electrolyte membrane 21 and the bonded gaskets 23a and 23b are in close contact with the sealing gasket 26 without any gaps. With such a configuration, oxygen leakage and hydrogen leakage can be suppressed while protecting the electrolyte membrane 21. In addition, the electrolyte membrane 21 can be supported more firmly.
The gasket 27a for integration is formed on the periphery of the surface opposite to the surface facing the membrane electrode assembly 24 on both surfaces of the gas diffusion layer 28a, and on the surface of the sealing gasket 26 adjacent to the periphery. It is arranged to straddle.
The integration gasket 27b includes a peripheral portion of the opposite surface of the gas diffusion layer 28b opposite to the surface facing the membrane electrode assembly 24, and the surface of the sealing gasket 26 adjacent to the peripheral portion. It is arranged to straddle.

The gas diffusion layers 28a and 28b are arranged with the membrane electrode assembly 24 interposed therebetween. The gas diffusion layer 28a is laminated on the cathode side catalyst layer 22a, and the gas diffusion layer 28b is formed on the anode side catalyst layer 22b. Are stacked.
The gas diffusion layers 28a and 28b have a substantially rectangular shape, and the width and length are larger than the width and length of the cathode side catalyst layer 22a and the anode side catalyst layer 22b. With such a configuration, the integration gaskets 27a and 27b can be disposed without overlapping the cathode side catalyst layer 22a and the anode side catalyst layer 22b. Further, when the membrane electrode assembly 24 is drawn into a pair of sheet-like members described later, the cathode side catalyst layer 22a and the anode side catalyst layer 22b may be overlapped with the width dimension and the length dimension of the gas diffusion layers 27a, 27b. It becomes easy.

Next, the material of the membrane electrode structure 20 according to the present embodiment will be described.
The electrolyte membrane 21 may be one generally used for a polymer electrolyte fuel cell. For example, a fluorine-based electrolyte membrane or a hydrocarbon electrolyte membrane can be suitably used, and a fluorine-based electrolyte membrane is particularly desirable.
The cathode side catalyst layer 22a and the anode side catalyst layer 22b may also be those generally used for solid polymer fuel cells. For example, platinum or fine particles (average particle size) of platinum and another metal (for example, ruthenium (Ru), rhodium (Rh), molybdenum (Mo), chromium (Cr), cobalt (Co), iron (Fe), etc.)) Conductive carbon fine particles such as carbon black (the average particle diameter is preferably about 20 to 100 nm) supported on the surface and a polymer solution such as a perfluorosulfonic acid resin solution. A catalyst ink that is uniformly mixed in an appropriate solvent (such as ethanol) can be used.

The sealing gasket 26 may be one generally used for polymer electrolyte fuel cells among thermoplastic resins. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polytetrafluoroethylene (PTFE), polyimide (PI) and the like can be used.
The gaskets 27a and 27b for integration may be those commonly used for polymer electrolyte fuel cells among thermosetting resins. For example, epoxy resin (EP), phenol resin (PF), polyimide (PI), unsaturated polyester (UP), etc. can be used.

The joined gaskets 23a and 23b may be those generally used for polymer electrolyte fuel cells among thermoplastic resins. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polytetrafluoroethylene (PTFE), polyimide (PI) and the like can be used.
The gas diffusion layers 28a and 28b may be those generally used for polymer electrolyte fuel cells as long as they have at least gas permeability (breathability) and conductivity. For example, woven fabrics, non-woven fabrics (felts obtained by entanglement of carbon fibers, etc.), papers (carbon papers, etc.) made of carbon materials are widely used.

Next, the manufacturing method of the membrane electrode structure according to the present embodiment will be described with reference to FIGS.
First, as shown in FIG. 4, in the first step, sealing gaskets 26a and 26b are attached to and integrated with the gas diffusion layers 28a and 28b. Specifically, first, sealing gaskets 26a and 26b are arranged so as to surround the outer peripheries of the gas diffusion layers 28a and 28b.

Next, the integration gaskets 27a and 27b are arranged so as to straddle the gas diffusion layers 28a and 28b and the sealing gaskets 26a and 26b, and the sheet-like member 10 is formed. Specifically, the integration gaskets 27a and 27b are arranged over all the one surfaces of the sealing gaskets 26a and 26b and the peripheral portions of the gas diffusion layers 28a and 28b, and are integrated by being semi-cured. The sheet-like member 10 is produced.
At this time, when the sheet-like member 10 is viewed from the side where the integration gaskets 27a and 27b are arranged, the sealing gaskets 26a and 26b are covered with the integration gaskets 27a and 28b so that they cannot be seen. .

  In the second step, the two sheet-like members 10 produced in the first step are overlapped, and a part of the peripheral portions of the peripheral portions of the sealing gaskets 26a and 26b of both the sheet-like members 10 are joined together to form a pair. These sheet-like members are joined together to produce a sheet-like member joined body. Specifically, as shown in FIGS. 4 and 5, the pair of sheet-like members 10, 10 are opposed to each other with the surface on which the sealing gaskets 26 a, 26 b are disposed facing each other. Only two opposite sides of the inner peripheral edge are joined. Sealed gaskets 26a and 26b are integrated in the joined portions (indicated by reference numeral 26 in FIG. 5). Joining is performed by welding by fusing, for example. In addition, since the sheet-like member 10 is produced by semi-curing the integration gaskets 27a and 27b in the first step, the sheet-like member assembly is easily melted in the second step. Can do.

In the third step, the membrane electrode assembly 24 is sandwiched and sealed between the sheet-like members 10 of the sheet-like member assembly produced in the second step. This will be described with reference to FIG.
First, a membrane formed by disposing gaskets 23a and 23b for joined bodies that surround the peripheral portion in the circumferential direction on the outer peripheral side of the peripheral portion of the cathode side catalyst layer 22a and the anode side catalyst layer 22b disposed with the electrolyte membrane 21 interposed therebetween. An electrode assembly 24 is prepared (see FIG. 6A). In the membrane electrode assembly 24 of the present embodiment, the outer peripheral surface of the peripheral portion of the cathode side catalyst layer 22a and the gasket 23a for the joined body, and the outer peripheral surface of the peripheral portion of the anode side catalyst layer 22b and the gasket for the joined body. It is desirable that 23b is in close contact with no gap. Thereby, the electrolyte membrane 21 can be supported more firmly.

The membrane electrode assembly 24 is drawn and sandwiched between the sheet-like member assemblies produced in the second step (see FIG. 6B). After sandwiching the membrane electrode assembly 24 in the center of the sheet-like member assembly, a sealing layer 29 is formed by welding by sealing the sealing gaskets 26a, 26b other than the portion welded in the second step, The membrane electrode assembly 24 is sealed in the sealing layer 29. FIG. 6C shows a state where the membrane electrode assembly 24 is sealed in the sealing layer 29. Originally, the integration gasket 27a is visible on the upper surface of the membrane electrode structure 20, and the sealing gasket 26 located below the integration gasket 27a is not visible, but in FIG. For the sake of convenience, the illustration of the integration gasket 27a is omitted.
At this time, it is desirable that the outer peripheral surface of the peripheral portion of the electrolyte membrane 21 and the outer peripheral surfaces of the peripheral portions of the joined body gaskets 23a and 23b are in close contact with the sealing gasket 26 after being melted and solidified. This is because the electrolyte membrane 21 can be supported more firmly.

  Thus, according to the manufacturing method of the membrane electrode structure 20 according to the present embodiment, the membrane electrode assembly 24 and the sealing layer 29 can be manufactured in separate steps. It is possible to simplify the process of stacking 20 layers. Therefore, the membrane electrode structure 20 can be manufactured easily and inexpensively. Furthermore, since each sheet-like member 10 disposed on the front and back of the membrane electrode assembly 24 can be formed as the sealing layer 29 at a time, the manufacturing process can be simplified.

In addition, it is possible to prevent the displacement between the front and back when the sheet-like members 10 are laminated, that is, the positional deviation between the gas diffusion layers 28a and 28b after lamination.
Further, when the sealing gasket 26 is welded, the gas diffusion layers 28a and 28b are also hot-pressed together so that the gas diffusion layer 28a and the cathode side catalyst layer 22a and the gas diffusion layer 28b and the anode side catalyst layer are heated. Since the adhesion of 22b is improved, the power generation performance is improved.
In addition, since the two sides of the sheet-like member assembly are open, the membrane electrode assembly 24 can be easily disposed in the sheet-like member assembly by drawing even the non-rigid membrane electrode assembly 24. Can do.

  Furthermore, the sealing gasket 29 and the integration gaskets 27a and 27b allow the sealing layer 29 to be produced without creating a gap between these gaskets and the gas diffusion layers 28a and 28b. Furthermore, since the membrane electrode assembly 24 can be sealed with no gap in the sealing layer 29, the peripheral edge of the electrolyte membrane 21 is sealed to prevent leakage of oxygen gas and hydrogen gas. Can be provided with a small number of parts.

  Below, the manufacturing method of the membrane electrode structure of this invention is demonstrated by a specific Example. In addition, a present Example is an Example of one Embodiment of this invention, and this invention is not limited to this Example.

[Making membrane electrode assembly]
A solvent (water, 1-propano) containing carbon carrying a platinum catalyst, perfluorocarbon sulfonic acid (a Nafion (registered trademark) solution manufactured by DuPont) was used, and amorphous carbon into which a sulfonic acid group was introduced. And 2-propanol were mixed in a 1: 1: 1 (volume ratio) solvent mixture, and a planetary ball mill (Pulverisete 7 manufactured by FRITSCH) was used. The ball mill pot and balls used were made of zirconia. ) Was used for dispersion treatment to prepare a catalyst ink. The solid content in the catalyst ink was 10% by mass.

The catalyst ink produced as described above was applied onto a transfer substrate and dried to form a catalyst layer. At this time, the catalyst layer was formed so that the mass of platinum (Pt) of the catalyst layer per unit area was 0.4 mg / cm ² . The obtained catalyst layer was punched out in a square shape of 50 mm square together with the transfer substrate to obtain a transfer sheet.
Subsequently, Nafion (registered trademark) XL manufactured by DuPont Co., Ltd. was used as the electrolyte membrane, and the electrolyte membrane was sandwiched between two transfer sheets so that the catalyst layer faced both surfaces of the electrolyte membrane. Thereafter, the electrolyte membrane sandwiched between these two transfer sheets was heated at 130 ° C., and hot pressing was performed for 10 minutes under pressure to obtain a membrane electrode assembly.

[Production of sheet-like member assembly]
A 60 mm square microporous layer (MPL) treated carbon paper is placed in the hole of the frame-shaped gasket film in which square holes of 60 mm square are formed by punching, and the periphery of the gasket film and the MPL treated carbon paper (from the outer edge) A fluoroether type adhesive was applied to a thickness of 35 μm by screen printing on the inside 1 cm. Next, the adhesive was semi-cured by heating at 70 ° C. for 5 minutes, and a sheet-like member composed of a gasket film and MPL-treated carbon paper was produced. Subsequently, the two sheet-like members are arranged so that the gasket film of the sheet-like member and the MPL-treated carbon paper face each other, and the two opposite sides are melted by a fusing sealer and joined together. A sheet-like member assembly as a member was obtained.
Next, the membrane electrode assembly was drawn from the opening of the sheet member assembly, and was placed in the sheet member assembly so that the MPL-treated carbon paper and the catalyst layer of the membrane electrode assembly overlapped. While heating this at 130 degreeC, the membrane electrode structure in this invention was obtained by performing the hot press hold | maintained under pressure for 10 minutes.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for a polymer electrolyte fuel cell single cell or a stack in a polymer electrolyte fuel cell, particularly a fuel cell automobile or a household fuel cell.

100 ... Single battery (cell)
DESCRIPTION OF SYMBOLS 10 ... Sheet-like member 20 ... Membrane electrode structure 21 ... Electrolyte membrane 22a ... Cathode side catalyst layer 22b ... Anode side catalyst layer 23a ... Assembly gasket 23b ... Joining Gasket for body 24 ... Membrane electrode assembly 26 ... Gasket for sealing 26a ... Gasket for sealing 26b ... Gasket for sealing 27a ... Gasket for integration 27b ... for integration Gasket 28a ... Gas diffusion layer 28b ... Gas diffusion layer 29 ... Sealing layer 30 ... Separator

Claims (9)

A first step of forming a sheet-like member formed by attaching and integrating a gasket to the gas diffusion layer;
A second step of superposing a pair of the sheet-like members and joining a part of the circumferential direction of the peripheral portion of the two sheet-like members;
A membrane / electrode assembly having an electrolyte membrane and a pair of catalyst layers disposed between the electrolyte membranes is sandwiched between the pair of joined sheet-like members, and the circumferential portions of the peripheral portions of the two sheet-like members are sandwiched. A third step of joining the rest and sealing the membrane electrode assembly in the pair of sheet-like members;
A method for producing a membrane electrode structure, comprising:   In the membrane / electrode assembly, the pair of catalyst layers is arranged in a portion excluding the peripheral portions on both surfaces of the electrolyte membrane, and the peripheral edges of the pair of catalyst layers are arranged on the outer peripheral side of the peripheral portions of the pair of catalyst layers. The manufacturing method of the membrane electrode structure according to claim 1, wherein a gasket for a joined body surrounding the portion in the circumferential direction is arranged.   The gasket attached to the gas diffusion layer in the first step is a sealing gasket, and in the first step, the sealing gasket is disposed so as to surround the outer periphery of the gas diffusion layer, and then the gas The integration gasket is disposed so as to straddle the diffusion layer and the sealing gasket, and the gas diffusion layer and the sealing gasket are integrated by the integration gasket. The manufacturing method of the membrane electrode structure of Claim 2.   The sheet-like member has a substantially rectangular shape, and in the second step, only two opposite sides of the sealing gasket arranged on the peripheral edge of the sheet-like member are joined, The method for producing a membrane electrode structure according to claim 3, wherein the sheet-like members are joined.   The sealing gasket is made of a thermoplastic resin, the integration gasket is made of a thermosetting resin, and only two opposing sides of the sealing gasket are welded in the second step. The method of manufacturing a membrane electrode structure according to claim 4, wherein bonding is performed.   6. The method for manufacturing a membrane electrode structure according to claim 5, wherein only two opposing sides of the sealing gasket are welded by fusing.   In the third step, the membrane electrode assembly is sealed in the pair of sheet-like members by welding a portion of the sealing gasket that has not been welded in the second step. A method for producing a membrane electrode structure according to claim 5 or 6. A membrane electrode assembly comprising an electrolyte membrane and a membrane electrode assembly having a pair of catalyst layers arranged with the electrolyte membrane interposed therebetween, and a sealing layer covering the entire membrane electrode assembly,
The sealing layer includes a pair of gas diffusion layers disposed across the membrane electrode assembly, a peripheral portion of the membrane electrode assembly, and a peripheral portion of the pair of gas diffusion layers in a circumferential direction. A membrane electrode structure comprising: a gasket; and an integration gasket that is disposed so as to straddle the sealing gasket and the gas diffusion layer, and that integrates the sealing gasket and the gas diffusion layer. body.   The pair of catalyst layers are arranged in portions excluding the peripheral edge portions on both surfaces of the electrolyte membrane, and are joined to surround the peripheral edge portions of the pair of catalyst layers in the circumferential direction on the outer peripheral side of the peripheral edge portions of the pair of catalyst layers. The membrane electrode structure according to claim 8, wherein a body gasket is arranged.

Images