JP2012015041A - Electrode-film-frame assembly, manufacturing method thereof, and fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode-film-frame assembly capable of further improving power generation performance.SOLUTION: In the electrode-film-frame assembly, a frame body 6 formed in a peripheral part 5E of a film electrode assembly 5 is configured so as to include an architrave-shaped handling part 61 and an architrave-shaped leakage prevention part 62. In order that each part can attain its function, the handling part 61 comprises thermoplastic resin with high elastic modulus comprising polypropylene filled with glass filler, and the leakage prevention part 62 comprises thermoplastic elastomer with low elastic modulus not filled with the glass filler.

Description

  The present invention relates to a fuel cell used as a driving source for a mobile body such as an automobile, a distributed power generation system, a household cogeneration system, and the like, and in particular, an electrode-membrane-frame assembly provided in the fuel cell and its manufacture. Regarding the method.

  BACKGROUND ART A fuel cell (for example, a polymer electrolyte fuel cell) is an apparatus that generates electric power and heat simultaneously by electrochemically reacting a fuel gas containing hydrogen and an oxidant gas containing oxygen such as air. It is.

  A fuel cell is generally configured by stacking a plurality of cells and pressurizing them with a fastening member such as a bolt. One cell is configured by sandwiching a membrane electrode assembly (hereinafter referred to as MEA: Membrane-Electrode-Assembly) between a pair of plate-like conductive separators. The MEA is held at its peripheral edge (also referred to as an outer edge) by a resin frame formed into a frame shape in order to improve handling properties. Here, the MEA including the frame is referred to as an electrode-membrane-frame assembly.

  The MEA includes a polymer electrolyte membrane whose peripheral portion is supported by the frame body, and a pair of electrode layers that are formed on both surfaces of the electrolyte membrane and disposed on the inner side of the frame body. The pair of electrode layers includes a catalyst layer made of platinum or the like formed on both surfaces of the polymer electrolyte membrane and a porous and conductive gas diffusion layer formed on the catalyst layer. When the fuel gas or the oxidant gas comes into contact with the pair of electrode layers, an electrochemical reaction is generated, and electric power and heat are generated. On the other hand, a gasket for sealing between the separator and the frame is provided on the surface of the frame, and leakage of fuel gas and oxidant gas to the outside is blocked or suppressed by the gasket.

  As the fuel cell having the above structure, for example, there is one disclosed in Patent Document 1 (International Publication No. WO2009 / 072291). In Patent Document 1, a primary molded body and a secondary molded body are formed by injection molding a secondary molded body on the other surface of the MEA after disposing a primary molded body on one surface of the MEA in the periphery of the MEA. It is disclosed that a frame is formed by integrating a body.

International Publication Number WO2009 / 072291

However, the conventional fuel cell has a problem that the power generation performance is not sufficient.
Accordingly, an object of the present invention is to provide an electrode-membrane-frame assembly, a method for producing the same, and a fuel cell that can further improve power generation performance.

In order to achieve the above object, the present invention is configured as follows.
According to the present invention, the first catalyst layer disposed on the first main surface of the polymer electrolyte membrane, the first gas diffusion layer disposed on the main surface of the first catalyst layer, and the first of the electrolyte membrane. A resin frame is formed at the peripheral edge of the membrane electrode assembly having the second catalyst layer disposed on the main surface of the second gas layer and the second gas diffusion layer disposed on the main surface of the second catalyst layer. Electrode-membrane-frame assembly, comprising:
The frame has a frame-shaped handling portion and a frame-shaped leak prevention portion made of different resin materials,
The handling portion is disposed on the first main surface side of the electrolyte membrane so that a peripheral edge portion of the electrolyte membrane and an inner edge portion of the handling portion overlap when viewed from the thickness direction of the electrolyte membrane,
The leak prevention portion is disposed on the second main surface side of the electrolyte membrane so that a peripheral edge portion of the electrolyte membrane and an inner edge portion of the leak prevention portion overlap each other when viewed from the thickness direction of the electrolyte membrane. Yes,
An electrode-membrane-frame assembly is provided.

  According to the electrode-membrane-frame assembly of the present invention, the frame is configured to have a handling part and a leak prevention part, and the handling part and the leak prevention part are made of different resin materials. . That is, the frame body is configured to have two parts, a part mainly responsible for the strength as the frame body and the handleability of the electrode-membrane-frame assembly, and a part mainly responsible for preventing cross leak. Thereby, the power generation performance of the fuel cell can be further improved while ensuring the desired handling property.

1 is a perspective view schematically showing a part of a structure of a fuel cell having an electrode-membrane-frame assembly according to a first embodiment of the present invention. FIG. 2 is a plan view schematically showing the configuration of the electrode-membrane-frame assembly in FIG. 1. It is the II-II sectional view taken on the line of FIG. It is a top view which shows the surface structure by the side of the anode separator of the electrode-membrane-frame assembly of FIG. FIG. 2 is a plan view showing the surface structure of the electrode-membrane-frame assembly of FIG. 1 on the cathode palator side. It is a side view which shows a mode that the handling part of a frame is hold | maintained at the holding member. It is a side view which shows a mode that the handling part of a frame is hold | maintained at the holding member different from FIG. It is a schematic cross section which expands and shows the manufacturing process of the electrode-membrane-frame assembly concerning 1st Embodiment of this invention, and the junction part of the peripheral part of MEA and a frame. It is a schematic cross section which shows the process of following FIG. 8A. It is a schematic cross section which shows the process of following FIG. 8B. It is a top view which shows typically the structure of the electrode-membrane-frame assembly concerning 2nd Embodiment of this invention. It is the IV-IV sectional view taken on the line of FIG. It is a schematic cross section which expands and shows the manufacturing process of the electrode-membrane-frame assembly concerning 2nd Embodiment of this invention, and the junction part of the peripheral part of MEA and a frame. It is a schematic cross section which shows the process of following FIG. 11A. It is a schematic cross section which shows the process following FIG. 11B. It is a schematic cross section which shows the process of following FIG. 11C. It is an expanded sectional view showing typically the modification of the electrode-membrane-frame assembly concerning a 1st embodiment of the present invention. It is an expanded sectional view showing typically the modification of the electrode-membrane-frame assembly concerning a 2nd embodiment of the present invention. It is a top view of the electrode-membrane-frame assembly concerning the Example of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG.

  The present inventors diligently studied the cause of insufficient power generation performance in the conventional fuel cell. As a result, the following knowledge was obtained.

Since the frame is provided in order to improve the handling property of the MEA at the time of assembling the cell, high strength is required. For this reason, the frame is configured, for example, by mixing an inorganic reinforcing material such as a glass filler in a thermoplastic resin such as polypropylene. However, when a secondary molded body is injection molded using a thermoplastic resin mixed with a reinforcing material such as a glass filler, the reinforcing material may damage the polymer electrolyte membrane due to the injection pressure, and the polymer electrolyte membrane may be deteriorated. is there. When the polymer electrolyte membrane deteriorates, a cross leak (gas short circuit) occurs and the power generation performance of the fuel cell decreases.
Based on these points, the inventors have reached the present invention described below.

According to the first aspect of the present invention, the first catalyst layer disposed on the first main surface of the polymer electrolyte membrane, the first gas diffusion layer disposed on the main surface of the first catalyst layer, A membrane electrode assembly having a second catalyst layer disposed on the second main surface of the electrolyte membrane and a second gas diffusion layer disposed on the main surface of the second catalyst layer is made of resin at a peripheral portion. An electrode-membrane-frame assembly in which a frame is formed,
The frame has a frame-shaped handling portion and a frame-shaped leak prevention portion made of different resin materials,
The handling portion is disposed on the first main surface side of the electrolyte membrane so that a peripheral edge portion of the electrolyte membrane and an inner edge portion of the handling portion overlap when viewed from the thickness direction of the electrolyte membrane,
The leak prevention portion is disposed on the second main surface side of the electrolyte membrane so that a peripheral edge portion of the electrolyte membrane and an inner edge portion of the leak prevention portion overlap each other when viewed from the thickness direction of the electrolyte membrane. Yes,
An electrode-membrane-frame assembly is provided.

  According to a second aspect of the present invention, there is provided the electrode-membrane-frame assembly according to the first aspect, wherein an elastic modulus of the leak preventing portion is lower than an elastic modulus of the handling portion.

  According to the third aspect of the present invention, the peripheral edge portion of the second catalyst layer is disposed outside the peripheral edge portion of the second gas diffusion layer when viewed from the thickness direction of the electrolyte membrane, and the second catalyst layer The electrode-membrane-frame assembly according to the first or second aspect is provided in which a part of the resin material constituting the leak preventing portion is mixed on the main surface of the peripheral portion of the layer.

  According to the fourth aspect of the present invention, the peripheral portion of the first catalyst layer is disposed outside the peripheral portion of the first gas diffusion layer when viewed from the thickness direction of the electrolyte membrane, and the first catalyst layer The electrode-membrane-frame assembly according to the third aspect is provided, in which a part of the resin material constituting the handling portion is not mixed on the main surface of the peripheral portion of the layer.

According to a fifth aspect of the present invention, the handling part is made of a thermoplastic resin,
The leak prevention part is made of a thermoplastic elastomer,
The electrode-membrane-frame assembly according to any one of the first to fourth aspects is provided.

According to the sixth aspect of the present invention, the handling part includes an inorganic reinforcing material,
The leak prevention part provides the electrode-membrane-frame assembly according to any one of the first to fifth aspects, which is included in the inorganic reinforcing material at a lower content than the handling part.

  According to a seventh aspect of the present invention, there is provided the electrode-membrane-frame assembly according to the sixth aspect, wherein the leak preventing part does not include the inorganic reinforcing material.

  According to the eighth aspect of the present invention, in any one of the first to seventh aspects, the resin material constituting the handling part and the resin material constituting the leak prevention part include at least one type of the same component. The description provides an electrode-membrane-frame assembly.

According to the ninth aspect of the present invention, the handling part is composed of an olefinic thermoplastic resin,
The leak prevention part is composed of an olefin-based thermoplastic elastomer,
The electrode-membrane-frame assembly according to any one of the first to eighth aspects is provided.

  According to a tenth aspect of the present invention, there is provided a fuel cell comprising the electrode-membrane-frame assembly according to any one of the first to ninth aspects.

According to an eleventh aspect of the present invention, the first catalyst layer disposed on the first main surface of the polymer electrolyte membrane, the first gas diffusion layer disposed on the main surface of the first catalyst layer, A frame body is provided at a peripheral portion of a membrane electrode assembly having a second catalyst layer disposed on the second main surface of the electrolyte membrane and a second gas diffusion layer disposed on the main surface of the second catalyst layer. A method for producing a formed electrode-membrane-frame assembly, comprising:
The manufacturing method includes:
When viewed from the thickness direction of the electrolyte membrane, a resin material is used so that the peripheral edge portion of the electrolyte membrane and the inner edge portion of the frame-shaped handling portion constituting a part of the frame body overlap each other. Forming the handling part on the main surface side of 1,
The resin material that constitutes the handling portion so that a peripheral edge portion of the electrolyte membrane overlaps with an inner edge portion of a frame-shaped leak prevention portion that constitutes the other portion of the frame body as viewed from the thickness direction of the electrolyte membrane. Forming the leak preventing portion on the second main surface side of the electrolyte membrane using a resin material having a lower elastic modulus than
A method for producing an electrode-membrane-frame assembly is provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
The structure of the fuel cell having the electrode-membrane-frame assembly according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view schematically showing a part of the structure of a fuel cell having an electrode-membrane-frame assembly according to the first embodiment. 2 is a plan view schematically showing the configuration of the electrode-membrane-frame assembly of FIG. 1, and FIG. 3 is a cross-sectional view taken along the line II-II of FIG. FIG. 4 is a plan view showing the surface structure of the electrode-membrane-frame assembly of FIG. 1 on the anode separator side. FIG. 5 is a plan view showing the surface structure of the electrode-membrane-frame assembly of FIG.

  The fuel cell according to the first embodiment is a polymer that generates electric power and heat simultaneously by electrochemically reacting a fuel gas containing hydrogen and an oxidant gas containing oxygen such as air. This is an electrolyte fuel cell. The present invention is not limited to the polymer electrolyte fuel cell, and can be applied to various fuel cells.

  As shown in FIG. 1, the fuel cell is configured by stacking a plurality (for example, 60) of cells (unit cell modules) 10 that are basic unit configurations. Although not shown, a current collector plate, an insulating plate, and an end plate are attached to both ends of the stacked cells 10 group, and fastening bolts are inserted through the bolt holes 4 and fixed with nuts. Each cell 10 is fastened with a predetermined fastening force (for example, 10 kN).

  The cell 10 is configured by sandwiching the electrode-membrane-frame assembly 1 between an anode separator 2 and a cathode separator 3 which are a pair of conductive separators. As shown in FIG. 2 or 3, the electrode-membrane-frame assembly 1 is a frame formed so as to seal and hold the membrane electrode assembly 5 (hereinafter referred to as MEA) and the peripheral portion 5E of the MEA 5. 6 is provided.

  As shown in FIG. 1, each of the anode separator 2, the cathode separator 3, and the frame 6 is provided with fuel gas manifold holes 12, 22, and 32, which are a pair of through holes through which fuel gas flows. Further, as shown in FIG. 1, the anode separator 2, the cathode separator 3 and the frame 6 are provided with oxidant gas manifold holes 13, 23 and 33, respectively, which are a pair of through holes through which the oxidant gas flows. It has been. In a state where the anode separator 2, the cathode separator 3, and the frame 6 are fastened as the cell 10, the fuel gas manifold holes 12, 22, and 32 are connected to form a fuel gas manifold. Similarly, when the anode separator 2, the cathode separator 3, and the frame 6 are fastened as the cell 10, the oxidant gas manifold holes 13, 23, and 33 are connected to form an oxidant gas manifold.

  Further, as shown in FIG. 1, the anode separator 2, the cathode separator 3, and the frame 6 have cooling medium manifold holes that are two pairs of through holes through which a cooling medium (for example, pure water or ethylene glycol) flows. 14, 24 and 34 are provided. As a result, in a state where the anode separator 2, the cathode separator 3, and the frame 6 are fastened as the cell 10, these cooling medium manifold holes 14, 24, and 34 are connected to form two pairs of cooling medium manifolds. The

  Further, as shown in FIG. 1, the anode separator 2, the cathode separator 3, and the frame body 6 are provided with four bolt holes 4 in the vicinity of each corner portion. A fastening bolt is inserted into each bolt hole 4, and each cell 10 is fastened by coupling a nut to the fastening bolt.

  A fuel gas passage groove 21 is provided on the inner main surface of the anode separator 2 (surface on the electrode-membrane-frame assembly 1 side) so as to connect the pair of fuel gas manifold holes 22, 22. An oxidant gas channel groove 31 is provided on the inner main surface of the cathode separator 3 (surface on the electrode-membrane-frame assembly 1 side) so as to connect the pair of oxidant gas manifold holes 33 and 33. Yes. The fuel gas is supplied to the first gas diffusion layer 5C1 of the MEA 5 to be described later through the fuel gas channel groove 21, and the oxidant gas is supplied to the second gas diffusion layer 5C2 of the MEA 5 to be described later through the oxidant gas channel groove 31. As a result, an electrochemical reaction of the fuel cell occurs. Thereby, electric power and heat are generated simultaneously. In FIG. 4, the one-dot broken line indicates the flow direction of the fuel gas. Moreover, in FIG. 5, the one-dot broken line has shown the flow direction of oxidizing gas. 4 and 5 show that the flow directions of the fuel gas and the oxidant gas meander, the present invention is not limited to this. For example, the fuel gas channel groove 21 and the oxidant gas channel groove 31 may be formed so that the flow directions of the fuel gas and the oxidant gas are linear.

  Moreover, although not shown in figure, the cooling medium flow path groove | channel is formed in the outer main surface (back surface) of the anode separator 2 and the cathode separator 3, respectively. The cooling medium flow channel is formed so as to connect the two pairs of cooling medium manifold holes 24 and 34. That is, the cooling medium is configured to branch from the cooling medium manifold on the supply side to the cooling medium flow channel and to flow to the cooling medium manifold on the discharge side. Thereby, the cell 10 is maintained at a predetermined temperature suitable for the electrochemical reaction by utilizing the heat transfer capability of the cooling medium.

  In addition, each said hole and each groove | channel can be formed by cutting process and a shaping | molding process, for example. Moreover, each said manifold is not limited to the said structure, A various deformation | transformation is possible. For example, each manifold may have a so-called external manifold structure. 2 and 3, illustration of each hole is omitted.

  As shown in FIG. 3, the MEA 5 includes a polymer electrolyte membrane 5A that selectively transports hydrogen ions, and a pair of first and second electrode layers 5D1 and 5D2 (that is, formed on both surfaces of the electrolyte membrane 5A). Anode electrode layer and cathode electrode layer). The first electrode layer 5D1 has a two-layer structure of a first catalyst layer 5B1 and a first gas diffusion layer 5C1. Similarly, the second electrode layer 5D2 has a two-layer structure of a second catalyst layer 5B2 and a second gas diffusion layer 5C2.

  The polymer electrolyte membrane 5A is composed of a solid polymer material exhibiting proton conductivity, for example, a perfluorosulfonic acid membrane (Nafion membrane manufactured by DuPont). The first and second catalyst layers 5B1 and 5B2 are, for example, porous members mainly composed of carbon powder carrying a platinum group metal catalyst, and the first main surface or the second main surface of the polymer electrolyte membrane 5A. Formed on the surface.

  The first gas diffusion layer 5C1 has both fuel gas permeability and electron conductivity, and is formed on the main surface of the first catalyst layer 5B1. The first gas diffusion layer 5C1 has a smaller outer size than the first catalyst layer 5B1, and is disposed on the main surface of the first catalyst layer 5B1 so that the peripheral edge of the first catalyst layer 5B1 is exposed. That is, the peripheral edge portion of the first catalyst layer 5B1 is disposed outside the peripheral edge portion of the first gas diffusion layer 5C1 when viewed from the thickness direction of the polymer electrolyte membrane 5A. The second gas diffusion layer 5C2 has both oxidant gas permeability and electron conductivity, and is formed on the main surface of the second catalyst layer 5B2. The second gas diffusion layer 5C2 has a smaller outer size than the second catalyst layer 5B2, and is disposed on the main surface of the second catalyst layer 5B2 so that the peripheral edge of the second catalyst layer 5B2 is exposed. That is, the peripheral edge portion of the second catalyst layer 5B2 is disposed outside the peripheral edge portion of the second gas diffusion layer 5C2 when viewed from the thickness direction of the polymer electrolyte membrane 5A.

  As the first and second gas diffusion layers 5C1 and 5C2, for example, a porous member composed mainly of conductive particles and a polymer resin can be used without using carbon fiber as a base material. In addition, as the first and second gas diffusion layers 5C1 and 5C2, for example, a conductive base material having a porous structure, which is manufactured using a carbon woven fabric or a carbon non-woven fabric in order to provide gas permeability. It may be used.

  As shown in FIGS. 2 and 3, the frame body 6 is composed of two frame-shaped molded bodies including a handling portion 61 and a leak prevention portion 62 that are injection-molded with different resin materials.

  As shown in FIG. 6 or 7, the handling unit 61 is a part that is held by a holding member 70 a or 70 b that moves the electrode-membrane-frame assembly 1 when the cell 10 is assembled. For this reason, the handling part 61 has the intensity | strength which can maintain the shape as the electrode-membrane-frame assembly 1, ie, the intensity | strength which can suppress a bending, bending, etc. of the electrode-membrane-frame assembly 1. FIG. If the length L1 in the surface direction of the held portion 61b of the handling portion 61 that is directly held by the holding member 70a or 70b is too short, it is difficult to be held by the holding member 70a or 70b, and the desired length It is difficult to ensure strength. In particular, when the length L1 of the held portion 61b is less than 7.0 mm, it becomes difficult for the resin to flow during the injection molding of the handling portion 61, and the molding is difficult. For this reason, the length L1 of the held portion 61b is preferably secured to 8.0 mm or more.

  Moreover, the handling part 61 has a substantially L-shaped cross section, and is disposed on the peripheral edge of the first catalyst layer 5B1 in the vicinity of the first gas diffusion layer 5C1. That is, the handling unit 61 is configured such that the polymer electrolyte membrane 5A overlaps the polymer electrolyte membrane 5A and the inner edge portion (a portion near the inner edge) 61a of the handling unit 61 when viewed from the thickness direction of the polymer electrolyte membrane 5A. Are arranged on the first main surface side (the lower side in FIG. 3). The handling part 61 is formed by injection molding using a resin material. The injection molding of the handling portion 61 is performed in advance before being disposed on the peripheral edge portion of the first catalyst layer 5B1. Therefore, since the injection pressure at the time of injection molding of the handling part 61 is not applied to the polymer electrolyte membrane 5A, deterioration of the polymer electrolyte membrane 5A can be suppressed.

  The resin material used for injection molding of the handling part 61 is preferably a crystalline resin rather than an amorphous resin from the viewpoint of chemical stability, and among them, a thermoplastic resin having high mechanical strength and high heat resistance. It is preferable that For example, as the thermoplastic resin, a so-called super engineering plastic grade resin such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), liquid crystal polymer (LCP), polyether nitrile (PEN), polystyrene (PS), Shinji An tactic polystyrene resin (SPS) or the like is preferable. These have a compression modulus of several thousand to several tens of thousands of MPa and a deflection temperature under load of 150 ° C. or more, and are suitable materials for the thermoplastic resin. Moreover, even if it is a resin material currently used widely, intensity | strength can be strengthened by mixing an inorganic type reinforcing material with the said resin material. As the inorganic reinforcing material, for example, glass fiber, glass filler, calcium carbonate, basic magnesium carbonate, virophilite, zinc white, talc, mica, barium sulfate, silicic acid, silicate, kaolin clay, etc. are suitable. is there. For example, polypropylene filled with glass filler (GFPP) has a modulus of elasticity several times that of unfilled polypropylene (compression modulus of 1,000 to 1,500 MPa) and has a deflection temperature under load close to 150 ° C. Yes. Therefore, it can be suitably used as the thermoplastic resin.

  The leak prevention unit 62 has a substantially rectangular cross section, and is disposed on the periphery of the second catalyst layer 5B2 in the vicinity of the second gas diffusion layer 5C2. That is, the leak preventing unit 62 is configured such that the polymer electrolyte membrane 5A and the inner edge 62a of the leak preventing unit 62 overlap each other when viewed from the thickness direction of the polymer electrolyte membrane 5A. It is arranged on the surface side (upper side in FIG. 3). The leak prevention unit 62 is formed by injection molding using a resin material different from that of the handling unit 61. The injection molding of the leak preventing unit 62 is performed after the MEA 5 is disposed on the handling unit 61, whereby the leak preventing unit 62 and the handling unit 61 are integrated to form the frame body 6.

  In addition, when the leak prevention part 62 is injection-molded, it is preferable to mix a part of resin material which comprises the leak prevention part 62 in the main surface of the peripheral part of 2nd catalyst layer 5B2 which is porous. Thereby, the adhesiveness of the leak prevention part 62 and 2nd catalyst layer 5B2 can be improved, and the joining force of the frame 6 and MEA5 can be strengthened. In addition, since the handling part 61 is previously injection-molded, a part of resin material which comprises the handling part 61 is not mixed in the main surface of the peripheral part of 1st catalyst layer 5B1.

  As shown in FIG. 6 or FIG. 7, the leak preventing portion 62 is a portion that is not held by the holding members 70a and 70b during assembly or the like. Accordingly, since it is not necessary to increase the strength to maintain the shape of the frame body 6, the leak preventing portion 62 is formed of a resin material having a lower elastic modulus (softer) than the handling portion 61, for example, a thermoplastic elastomer. Yes. Thereby, when the cell 10 is pressure-fastened, mechanical stress (local load) applied to the peripheral portion 5E of the MEA 5 adjacent to the leak preventing portion 62 can be reduced, and crossing due to deterioration of the polymer electrolyte membrane 5A can be achieved. Leakage can be prevented. Further, since the elastic modulus of the leak preventing portion 62 is low (soft), a reaction force corresponding to the fastening load is likely to be generated, and the sealing performance of the reactive gas is enhanced, and the leak preventing effect is enhanced. In the case where the leak preventing portion 62 is formed of a material having a relatively high elastic modulus (hard), mechanical stress applied to the peripheral portion 5E of the MEA 5 at the time of pressure fastening of the cell 10 increases, and the polymer electrolyte The film 5A is easily damaged.

  In general, the elastic modulus of the resin material decreases as the amount of the inorganic reinforcing material decreases. Therefore, the elastic modulus of the leak prevention unit 62 can be made lower than that of the handling unit 61 by making the content of the reinforcing material in the leak prevention unit 62 smaller than that of the handling unit 61. Thereby, it can suppress that polymer electrolyte membrane 5A deteriorates with the reinforcing material in the leak prevention part 62, and can prevent a cross leak. The leak prevention unit 62 may not include any inorganic reinforcing material. Thereby, deterioration of the polymer electrolyte membrane 5A can be further suppressed.

  In addition, it is preferable that the length L3 in the surface direction of the leak prevention unit 62 is 4.0 mm or more so that the leak prevention unit 62 can cover the entire peripheral portion 5E of the MEA 5. Further, if the joining length L2 in the surface direction between the leak preventing portion 62 and the handling portion 61 is too short, there is a possibility that cross leak may occur. Therefore, it is preferable to secure 1.0 mm or more.

  Examples of the resin material used for the injection molding of the leak prevention unit 62 include olefin elastomer (TPO), styrene elastomer (TPS), polyester elastomer (TPEE), polyurethane elastomer (TPU), and nylon elastomer (TPA). Etc. are suitable. The olefin-based elastomer is constituted by mixing polypropylene (PP) and ethylene / propylene rubber (EPM) or ethylene / propylene / diene rubber (EPDM). The styrene elastomer is constituted by copolymerizing polystyrene (PS) and polybutadiene or polyisoprene.

  Moreover, generally, the joining force is stronger in joining the same resin materials than in joining the different resin materials. For this reason, as a resin material used for the leak prevention part 62, what contains the same homogeneous component as the resin material used for the handling part 61 is preferable. For example, when an olefinic thermoplastic resin such as polypropylene (GFPP) filled with a glass filler is used for the handling part 61, an olefinic thermoplastic such as santoprene (manufactured by AES Japan: registered trademark) is used for the leak prevention part 62. It is preferred to use an elastomer (TPO). When polystyrene (PS) is used for the handling part 61, it is preferable to use a styrene-based thermoplastic elastomer (TPS) for the leak prevention part 62.

  Next, a method for manufacturing the electrode-membrane-frame assembly 1 will be described. 8A to 8C are schematic cross-sectional views showing the manufacturing steps of the electrode-membrane-frame assembly 1 by enlarging the joint portion between the peripheral edge portion 5E of the MEA 5 and the frame body 6. FIG. Here, it is assumed that the handling unit 61 is injection-molded in advance and the MEA 5 is manufactured in advance.

  First, as illustrated in FIG. 8A, the handling unit 61 is disposed on the peripheral portion of the first catalyst layer 5B1 in the vicinity of the first gas diffusion layer 5C1 of the MEA5. At this time, since the handling part 61 is injection-molded in advance, the polymer electrolyte membrane 5A does not deteriorate even if the resin material includes an inorganic reinforcing material. Further, a part of the resin material constituting the handling part 61 is not mixed on the main surface of the peripheral edge part of the first catalyst layer 5B1.

  Next, as shown in FIG. 8B, the handling part 61 and the MEA 5 are sandwiched between the pair of molds T1, and the molten resin material is poured into the gap between the handling part 61 and the MEA 5 formed in the pair of molds T1. As a result, as shown in FIG. 8C, the leak preventing portion 62 is formed on the peripheral portion of the second catalyst layer 5B2 in the vicinity of the second gas diffusion layer 5C2 of the MEA5. At this time, the leak preventing unit 62 and the handling unit 61 are integrated to form the frame body 6. Thereby, manufacture of the electrode-membrane-frame assembly 1 is completed.

  In addition, at the time of the said injection molding, by mixing a part of resin material which comprises the leak prevention part 62 in a part of peripheral part of 2nd catalyst layer 5B2, the leak prevention part 62 and 2nd catalyst layer 5B2 are mixed. Adhesion is enhanced and the bonding force between the frame body 6 and the MEA 5 is enhanced. Further, by mixing the resin material in the porous second catalyst layer 5B2, the amount of pores in the second catalyst layer 5B2 is reduced, and the reaction gas is prevented from diffusing in the second catalyst layer 5B2. The This makes it possible to suppress contact between the fuel gas and the oxidant gas. Further, at the time of the injection molding, an injection pressure is applied to the peripheral portion 5E of the MEA 5, but the resin material used for the injection molding of the leak preventing portion 62 has a lower elastic modulus than that of the handling portion 61. Mechanical stress applied to the peripheral edge 5E is reduced. Therefore, deterioration due to perforation or thinning of the polymer electrolyte membrane 5A is suppressed, and cross leakage is prevented.

  According to the first embodiment, the frame 6 is configured to have the handling part 61 and the leak prevention part 62, and the handling part 61 and the leak prevention part 62 are made of different resin materials. That is, the frame body 6 is configured so as to have two parts, a part mainly responsible for the strength as the frame body 6 and the handling property of the electrode-membrane-frame assembly 1 and a part mainly responsible for preventing cross leak. Yes. Therefore, by selecting an optimal resin material for each of the handling unit 61 and the leak prevention unit 62, it is possible to maximize the respective functions. For example, by using a resin material (for example, a thermoplastic resin) having a high elastic modulus for the handling portion 61, desired handling properties can be ensured. Further, by using a resin material having a low elastic modulus (for example, a thermoplastic elastomer) for the leak prevention portion 62, the peripheral portion of the MEA 5 is provided at the time of manufacturing the frame body 6 (initial stage) and during power generation of the fuel cell (during durable operation). Such mechanical stress can be reduced and deterioration of the polymer electrolyte membrane 5A can be suppressed. Further, since the elastic modulus of the leak preventing portion 62 is low (soft), a reaction force corresponding to the fastening load is likely to be generated, and the sealing performance of the reactive gas is enhanced, and the leak preventing effect is enhanced. Therefore, the power generation performance of the fuel cell can be further improved.

  In addition, this invention is not limited to the said 1st Embodiment, It can implement in another various aspect. For example, in the first embodiment, the handling unit 61 is disposed on the anode side, and the leak prevention unit 62 is disposed on the cathode side. However, the handling unit 61 is disposed on the cathode side, and the leak prevention unit 62 is disposed on the anode side. You may arrange in.

  Moreover, in the said 1st Embodiment, although the inner edge part 61a of the handling part 61 was arrange | positioned on the peripheral part of catalyst layer 5B1, this invention is not limited to this. For example, the inner edge portion 61a of the handling portion 61 may be disposed on the first main surface of the polymer electrolyte membrane 5A. Similarly, the inner edge portion 62a of the leak preventing portion 62 may be disposed not on the second catalyst layer 5B2 but on the second main surface of the polymer electrolyte membrane 5A.

  In the first embodiment, the first catalyst layer 5B1 has the same size as the polymer electrolyte membrane 5A, but the present invention is not limited to this. For example, the size of the first catalyst layer 5B1 may be the same as the first gas diffusion layer 5C1 or smaller than the first gas diffusion layer 5C1. Similarly, the size of the second catalyst layer 5B1 may be the same as the second gas diffusion layer 5C2 or smaller than the second gas diffusion layer 5C2.

  In the first embodiment, the peripheral edge portion of the first gas diffusion layer 5C1 and the peripheral edge portion of the second gas diffusion layer 5C2 are arranged so as to coincide with each other when viewed from the thickness direction of the polymer electrolyte membrane 5A. You may arrange | position those peripheral parts by shifting in the surface direction orthogonal to a thickness direction mutually.

<< Second Embodiment >>
FIG. 9 is a plan view schematically showing the configuration of the electrode-membrane-frame assembly according to the second embodiment of the present invention, and FIG. 10 is a sectional view taken along line IV-IV in FIG. The electrode-membrane-frame assembly 1A according to the second embodiment is different from the electrode-membrane-frame assembly 1 according to the first embodiment in that the handling portion 61 and the leak prevention portion 62 are integrated. This is a point that the frame body 6A further has the joint portion 63.

  The joining part 63 is formed by injection molding using a resin material. The injection molding of the joining portion 63 is performed after the handling portion 61 is disposed on the peripheral portion of the first catalyst layer 5B1 and the leak preventing portion 62 is disposed on the peripheral portion of the second catalyst layer 5B2. The handling part 61 and the leak prevention part 62 are integrated by the joining part 63 to constitute the frame body 6A.

  In addition, when injection-molding the junction part 63, it is preferable to mix a part of resin material which comprises the junction part 62 in the main surface of the peripheral part of 2nd catalyst layer 5B2. Thereby, the adhesiveness of the junction part 63 and 2nd catalyst layer 5B2 can be improved, and the joining force of 6 A of frames and MEA5 can be strengthened. Further, by mixing the resin material in the porous second catalyst layer 5B2, the amount of pores in the second catalyst layer 5B2 is reduced, and the reaction gas is prevented from diffusing in the second catalyst layer 5B2. The This makes it possible to suppress contact between the fuel gas and the oxidant gas. Further, since the joining force between the frame 6A and the MEA 5 can be strengthened by the joining part 63, the injection molding of the leak preventing part 62 is performed in advance before being arranged on the peripheral part of the second catalyst layer 5B2. May be. In this case, since the injection pressure at the time of injection molding of the leak preventing portion 62 is not applied to the polymer electrolyte membrane 5A, deterioration due to perforation or thinning of the polymer electrolyte membrane 5A can be further suppressed. In this case, a part of the resin material constituting the leak preventing unit 62 is not mixed on the main surface of the peripheral portion of the second catalyst layer 5B2. Further, when the injection molding of the leak preventing portion 62 is performed in advance, the inorganic reinforcing material is suppressed from damaging the polymer electrolyte membrane 5A. Therefore, the leak preventing portion 62 is provided with an inorganic reinforcing material. Even if they are mixed, cross leakage can be prevented.

  As the resin material used for the injection molding of the joint part 63, a resin material containing the same components as the resin material of the handling part 61 and the resin material of the leak prevention part 62 is preferable. Thereby, the joining force of the handling part 61 and the leak prevention part 62 can be strengthened. Further, it is preferable that the content of the inorganic reinforcing material in the joint portion 63 is smaller than that in the handling portion 61. Thereby, it can suppress that 5 A of polymer electrolyte membranes deteriorate with the reinforcing material in the junction part 63. FIG. In addition, the junction part 63 does not need to contain an inorganic reinforcement material at all. Thereby, deterioration of the polymer electrolyte membrane 5A can be further suppressed.

  Next, a method for producing the electrode-membrane-frame assembly 1A will be described. FIG. 11A to FIG. 11C are schematic cross-sectional views showing each manufacturing process of the electrode-membrane-frame assembly 1A by enlarging the joint portion between the peripheral edge 5E of the MEA 5 and the frame 6A. Here, it is assumed that the handling unit 61 and the leak prevention unit 62 are injection molded in advance, and the MEA 5 is manufactured in advance.

  First, as shown in FIG. 11A, the handling unit 61 is disposed on the peripheral edge of the first catalyst layer 5B1 in the vicinity of the first gas diffusion layer 5C1 of the MEA 5. At this time, since the handling part 61 is injection-molded in advance, the polymer electrolyte membrane 5A does not deteriorate even if the resin material includes an inorganic reinforcing material. Further, a part of the resin material constituting the handling part 61 is not mixed on the main surface of the peripheral edge part of the first catalyst layer 5B1.

  Next, as illustrated in FIG. 11B, the leak prevention unit 62 is disposed on the peripheral portion of the second catalyst layer 5B2 in the vicinity of the second gas diffusion layer 5C2 of the MEA 5. At this time, since the leak preventing portion 62 is injection-molded in advance, the polymer electrolyte membrane 5A does not deteriorate even if the resin material contains an inorganic reinforcing material. In addition, a part of the resin material constituting the leak preventing unit 62 is not mixed on the main surface of the peripheral portion of the second catalyst layer 5B2.

  Next, as shown in FIG. 11C, the handling unit 61, the leak prevention unit 62, and the MEA 5 are sandwiched between the pair of molds T2, and the handling unit 61, the leak prevention unit 62, and the MEA 5 formed in the pair of molds T2. Pour molten resin material into the gap. As a result, as shown in FIG. 11D, a joint 63 is formed on the peripheral edge of the second catalyst layer 5B2 in the vicinity of the second gas diffusion layer 5C2 of the MEA 5. Further, at this time, the leak preventing portion 62 and the handling portion 61 are integrated by the joining portion 63 to constitute the frame body 6A. Thereby, the manufacture of the electrode-membrane-frame assembly 1A is completed.

  In addition, at the time of the said injection molding, the adhesiveness of the junction part 63 and 2nd catalyst layer 5B2 is mixed by mixing a part of resin material which comprises the junction part 63 in a part of peripheral part of 2nd catalyst layer 5B2. Increases, and the bonding force between the frame 6A and the MEA 5 is strengthened. Further, by mixing the resin material in the porous second catalyst layer 5B2, the amount of pores in the second catalyst layer 5B2 is reduced, and the reaction gas is prevented from diffusing in the second catalyst layer 5B2. The This makes it possible to suppress contact between the fuel gas and the oxidant gas. Further, at the time of the injection molding, an injection pressure is applied to the peripheral portion 5E of the MEA 5. However, the resin material used for the injection molding of the joint portion 63 has a lower elastic modulus than that of the handling portion 61. The mechanical stress applied to the part 5E is reduced. Therefore, deterioration due to perforation or thinning of the polymer electrolyte membrane 5A is suppressed, and cross leakage is prevented.

  In the first and second embodiments, the first and second catalyst layers 5B1 and 5B2 are formed in the same size as shown in FIGS. 3 and 10, but the present invention is not limited to this. For example, as shown in FIGS. 12 and 13, the first and second catalyst layers 5B1 and 5B2 may have different sizes. 12 and 13 show an example in which the size of the first catalyst layer 5B1 is smaller than the size of the second catalyst layer 5B2.

"Example"
Next, the electrode-membrane-frame assembly 1 according to an example of the present invention will be described with reference to FIGS. 14 is a plan view of the electrode-membrane-frame assembly 1 according to an embodiment of the present invention, FIG. 15 is a cross-sectional view taken along the line AA, and FIG. 16 is a cross-sectional view taken along the line BB. .

In the present example, the handling unit 61 was injection molded using polypropylene filled with glass filler as a resin material (manufactured by Prime Polymer Co., Ltd .: R-350G, glass filler amount 30 wt%). The injection molding of the handling part 61 was performed before disposing on the peripheral part of the first catalyst layer 5B1. The length L1 in the surface direction of the held portion 61b of the handling portion 61 was 45.5 mm in the AA cross section and 8.5 mm in the BB cross section. The length H1 in the thickness direction of the held portion 61b of the handling portion 61 was 0.77 mm in the AA section and 1.48 mm in the BB section. The length H2 in the thickness direction of the portion of the handling portion 61 that contacts the MEA 5 was 0.40 mm in the AA section and 0.88 mm in the BB section. The cross-sectional area of the handling portion 61 was 37.835 mm ^{2 in the} AA cross section and 18.740 mm ² in the BB cross section.

The leak prevention unit 62 was injection molded using Santoprene (registered trademark) 101-55 not filled with glass filler as a resin material. The injection molding of the leak preventing unit 62 was performed using the pair of molds T1 after the handling unit 61 was disposed on the peripheral portion of the first catalyst layer 5B1. The joining length L2 in the surface direction between the leak prevention unit 62 and the handling unit 61 is 1.0 mm for both the AA cross section and the BB cross section. The length L3 in the surface direction of the leak preventing portion 62 is 4.5 mm for both the AA cross section and the BB cross section. The length H3 in the thickness direction of the leak preventing portion 62 was 0.37 mm in the AA section and 0.60 mm in the BB section. The cross-sectional area of the leak preventing portion 62 was 1.595 mm ^{2 in the} AA cross section and 3.000 mm ² in the BB cross section. In this case, the ratio of the cross-sectional areas of the handling part 61 and the leak prevention part 62 is 24: 1 at the maximum and 6: 1 at the minimum.

  The first gas diffusion layer 5C1 and the second gas diffusion layer 5C2 are arranged so as to be shifted in the plane direction, and the shift amount L4 is 1.5 mm.

  It is to be noted that, by appropriately combining any of the various embodiments, the effects possessed by them can be produced.

  Since the electrode-membrane-frame assembly, the manufacturing method thereof, and the fuel cell according to the present invention can further improve the power generation performance, for example, a mobile body such as an automobile, a distributed power generation system, and a home cogeneration system It is useful for a fuel cell used as a drive source for the above.

1 Electrode-membrane-frame assembly 2 Anode separator 3 Cathode separator 4 Bolt hole 5 MEA (membrane electrode assembly)
5A polymer electrolyte membrane 5B1 first catalyst layer 5B2 second catalyst layer 5C1 first gas diffusion layer 5C2 second gas diffusion layer 5D1 first electrode layer 5D2 second electrode layer 5E peripheral edge 6 frame 10 cell 12, 22, 32 Fuel gas manifold hole 13, 23, 33 Oxidant gas manifold hole 14, 24, 34 Cooling medium manifold hole 21 Fuel gas channel groove 31 Oxidant gas channel groove 61 Handling part 62 Leak prevention part T1 Mold

Claims (11)

A first catalyst layer disposed on the first main surface of the polymer electrolyte membrane, a first gas diffusion layer disposed on the main surface of the first catalyst layer, and a second main surface of the electrolyte membrane An electrode-membrane-, in which a resin frame is formed on the peripheral edge of a membrane electrode assembly having the second catalyst layer formed and the second gas diffusion layer disposed on the main surface of the second catalyst layer A frame joined body,
The frame has a frame-shaped handling portion and a frame-shaped leak prevention portion made of different resin materials,
The handling portion is disposed on the first main surface side of the electrolyte membrane so that a peripheral edge portion of the electrolyte membrane and an inner edge portion of the handling portion overlap when viewed from the thickness direction of the electrolyte membrane,
The leak prevention portion is disposed on the second main surface side of the electrolyte membrane so that a peripheral edge portion of the electrolyte membrane and an inner edge portion of the leak prevention portion overlap each other when viewed from the thickness direction of the electrolyte membrane. Yes,
Electrode-membrane-frame assembly.   2. The electrode-membrane-frame assembly according to claim 1, wherein an elastic modulus of the leak preventing portion is lower than an elastic modulus of the handling portion.   The peripheral portion of the second catalyst layer is disposed outside the peripheral portion of the second gas diffusion layer when viewed from the thickness direction of the electrolyte membrane, and the main surface of the peripheral portion of the second catalyst layer The electrode-membrane-frame assembly according to claim 1 or 2, wherein a part of the resin material constituting the leak preventing portion is mixed.   The peripheral edge portion of the first catalyst layer is disposed outside the peripheral edge portion of the first gas diffusion layer as viewed from the thickness direction of the electrolyte membrane, and the main surface of the peripheral edge portion of the first catalyst layer has the The electrode-membrane-frame assembly according to claim 3, wherein a part of the resin material constituting the handling part is not mixed. The handling part is made of a thermoplastic resin,
The leak prevention part is made of a thermoplastic elastomer,
The electrode-membrane-frame assembly according to any one of claims 1 to 4. The handling part includes an inorganic reinforcing material,
The electrode-membrane-frame assembly according to any one of claims 1 to 5, wherein the leak prevention unit includes the inorganic reinforcing material at a lower content than the handling unit.   The electrode-membrane-frame assembly according to claim 6, wherein the leak prevention unit does not include the inorganic reinforcing material.   The electrode-membrane-frame assembly according to any one of claims 1 to 7, wherein the resin material constituting the handling part and the resin material constituting the leak prevention part contain at least one kind of the same component. The handling part is composed of an olefinic thermoplastic resin,
The leak prevention part is composed of an olefin-based thermoplastic elastomer,
The electrode-membrane-frame assembly according to any one of claims 1 to 8.   A fuel cell comprising the electrode-membrane-frame assembly according to any one of claims 1 to 9. A first catalyst layer disposed on the first main surface of the polymer electrolyte membrane, a first gas diffusion layer disposed on the main surface of the first catalyst layer, and a second main surface of the electrolyte membrane An electrode-membrane-frame assembly in which a frame is formed at the peripheral edge of a membrane electrode assembly having the second catalyst layer formed and the second gas diffusion layer disposed on the main surface of the second catalyst layer A manufacturing method of
The manufacturing method includes:
When viewed from the thickness direction of the electrolyte membrane, a resin material is used so that the peripheral edge portion of the electrolyte membrane and the inner edge portion of the frame-shaped handling portion constituting a part of the frame body overlap each other. Forming the handling part on the main surface side of 1,
The resin material that constitutes the handling portion so that a peripheral edge portion of the electrolyte membrane overlaps with an inner edge portion of a frame-shaped leak prevention portion that constitutes the other portion of the frame body as viewed from the thickness direction of the electrolyte membrane. Forming the leak preventing portion on the second main surface side of the electrolyte membrane using a resin material having a lower elastic modulus than
A method for producing an electrode-membrane-frame assembly comprising:

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