JP2007087728A - Laminate, method of manufacturing it, as well as fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain an electrolyte film from being degraded due to product water collected at a peripheral edge part of a catalyst layer, in a laminate having an electrolyte film and a catalyst layer for an electrode. <P>SOLUTION: The method of manufacturing the laminate 20, provided with an electrolyte film 11, a catalyst layer for an electrode fitted to either face of the electrolyte film 11, and a diffusion layer 13 jointed to the electrolyte film 11 through the catalyst layer 12, includes a crimping process carrying out crimping in such a condition that a vicinity of an interface (a region A) of the electrolyte film 11 with a peripheral edge part 12a of the catalyst layer 12 is to be nearly a plane. By making the vicinity of the interface of the electrolyte film 11 with the periphery edge part 12a of the catalyst layer 12 nearly plane, product water is restrained from collecting at the periphery edge part 12a of the catalyst layer 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laminate, a manufacturing method thereof, and a fuel cell.

A solid polymer electrolyte fuel cell is composed of a membrane-electrode assembly (MEA) consisting of an electrolyte membrane and an electrode catalyst layer, and a membrane / electrode / diffusion layer junction formed by joining a diffusion layer to the membrane / electrode assembly (MEA). The body (MEGA: Membrane-Electrode-Gas diffusion layer Assembly) is provided. In recent years, there has been proposed a method for producing a membrane / electrode / diffusion layer assembly by press-bonding an electrolyte membrane, an electrode catalyst layer, and a diffusion layer such as a carbon cloth by a hot press method ( For example, see Patent Document 1.)
Japanese Patent No. 3492385

  Incidentally, the electrode catalyst layer constituting the membrane-electrode assembly is generally smaller in area than the electrolyte membrane. Therefore, the peripheral portion of the membrane / electrode assembly is composed only of the electrolyte membrane, and the thickness of the peripheral portion is thinner than the central portion formed of the electrolyte membrane and the catalyst layer.

  For this reason, the diffusion layer 130 is formed on the membrane-electrode assembly 100 including the electrolyte membrane 110 and the catalyst layer 120 as shown in FIG. , The gap 200 is formed between the electrolyte membrane 110 and the diffusion layer 130 along the peripheral edge 121 of the catalyst layer 120, and moisture (generated water) generated by power generation is accumulated in the gap 200. . When the generated water accumulates in the gap 200 as described above, the electrolyte membrane 110 is chemically deteriorated by hydrogen peroxide and radicals contained in the generated water, so that the durability of the electrolyte membrane 110 is reduced and the power generation efficiency of the fuel cell is reduced. Problems may occur.

  The present invention has been made in view of such circumstances, and in a laminate having an electrolyte membrane and a catalyst layer for an electrode, it is possible to suppress the generation of water in the peripheral portion of the catalyst layer and the deterioration of the electrolyte membrane. With the goal.

  In order to achieve the above object, a laminate according to the present invention includes an electrolyte membrane, an electrode catalyst layer provided on both surfaces of the electrolyte membrane, and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer. , Wherein the vicinity of the boundary between the diffusion layer and the peripheral edge of the catalyst layer is substantially flat.

  According to such a configuration, since the vicinity of the boundary between the diffusion layer and the peripheral portion of the catalyst layer is substantially flat, it is possible to suppress the generation water from being accumulated in the peripheral portion (between the electrolyte membrane and the diffusion layer) of the catalyst layer. be able to. As a result, since chemical degradation of the electrolyte membrane can be suppressed, durability of the electrolyte membrane can be improved and power generation efficiency can be increased.

  In the laminate, a recess may be provided on the surface of the diffusion layer on the catalyst layer side, and at least the peripheral edge of the catalyst layer may be embedded in the recess.

  In addition, a laminate according to the present invention includes an electrolyte membrane, a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane, and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer. A recess is provided on each of the surface of the electrolyte membrane and the surface of the diffusion layer on the catalyst layer side, and a space is formed by arranging these recesses facing each other, and at least a peripheral portion of the catalyst layer is formed in this space. Is filled.

  According to such a configuration, since at least the peripheral portion of the catalyst layer is filled in the space formed by disposing the concave portions provided on the surface of the electrolyte membrane and the surface of the diffusion layer so as to face each other, the peripheral portion of the catalyst layer ( It is possible to prevent the generated water from accumulating between the electrolyte membrane and the diffusion layer. As a result, since chemical degradation of the electrolyte membrane can be suppressed, durability of the electrolyte membrane can be improved and power generation efficiency can be increased.

  In the laminate, the catalyst layer may be an anode electrode catalyst layer and a cathode electrode catalyst layer, and the area of the anode electrode catalyst layer may be different from the area of the cathode electrode catalyst layer. For example, the area of the cathode electrode catalyst layer is made smaller than the area of the anode electrode catalyst layer (the position of the periphery of the cathode electrode catalyst layer is closer to the center in plan view than the position of the periphery of the anode electrode catalyst layer). By doing so, it becomes possible to extend the useful life of the laminate.

  Moreover, the fuel cell according to the present invention comprises the laminate.

  When such a configuration is adopted, the power generation efficiency can be increased because the laminated body that can suppress the chemical deterioration of the electrolyte membrane is provided.

  Further, the method for producing a laminate according to the present invention is a method for producing a laminate comprising an electrolyte membrane and a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane, the periphery of the electrolyte membrane and the catalyst layer. This includes a crimping process for crimping under the condition that the vicinity of the boundary with the portion is substantially flat.

  According to this method, since the vicinity of the boundary between the electrolyte membrane and the peripheral edge of the catalyst layer can be made substantially flat, even when the diffusion layer is joined to the electrolyte membrane of the laminate via the catalyst layer, the catalyst layer It can suppress that generated water accumulates in the peripheral part. As a result, since chemical degradation of the electrolyte membrane can be suppressed, durability of the electrolyte membrane can be improved and power generation efficiency can be increased.

  In the said manufacturing method, a crimping | compression-bonding process can also include the diffusion layer joining process of joining a diffusion layer to both surfaces of an electrolyte membrane via a catalyst layer.

  Further, the method for producing a laminate according to the present invention includes an electrolyte membrane, a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane, and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer. It is a manufacturing method of the laminated body provided, Comprising: The crimping | compression-bonding process of crimping | bonding on the conditions that the boundary vicinity of a diffusion layer and the peripheral part of a catalyst layer becomes a substantially plane is included.

  According to such a method, the vicinity of the boundary between the diffusion layer and the peripheral portion of the catalyst layer can be made substantially flat, so that the generated water accumulates in the peripheral portion of the catalyst layer (between the electrolyte membrane and the diffusion layer). Can be suppressed. As a result, since chemical degradation of the electrolyte membrane can be suppressed, durability of the electrolyte membrane can be improved and power generation efficiency can be increased.

  Further, the method for producing a laminate according to the present invention includes an electrolyte membrane, a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane, and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer. A method of manufacturing a laminate comprising: a concave portion provided on a surface of an electrolyte membrane and a surface of a diffusion layer on a catalyst layer side; and a space is formed by disposing the concave portions facing each other, and a catalyst is formed in the space. It includes a pressure-bonding step in which pressure-bonding is performed under a condition that fills at least the peripheral edge of the layer.

  According to such a method, since at least the peripheral portion of the catalyst layer can be filled in the space formed by disposing the concave portions provided on the surface of the electrolyte membrane and the surface of the diffusion layer so as to face each other, the peripheral portion of the catalyst layer It can suppress that produced water accumulates (between the electrolyte membrane and the diffusion layer). As a result, since chemical degradation of the electrolyte membrane can be suppressed, durability of the electrolyte membrane can be improved and power generation efficiency can be increased.

  According to the present invention, in a laminate having an electrolyte membrane and an electrode catalyst layer, it is possible to suppress the generation water from accumulating in the peripheral portion of the catalyst layer, and thus it is possible to suppress deterioration of the electrolyte membrane. .

  Hereinafter, a fuel cell according to an embodiment of the present invention will be described with reference to the drawings. The fuel cells according to the following embodiments are solid polymer electrolyte fuel cells suitable for in-vehicle use.

<First Embodiment>
First, the fuel cell 1 which concerns on 1st Embodiment of this invention is demonstrated using FIGS. 1-3.

  As shown in FIG. 1, the fuel cell 1 according to the present embodiment includes a stack body 2 in which a plurality of unit cells 10 are stacked, and an output terminal is provided outside the unit cell 10 positioned at both ends of the stack body 2. The attached current collecting plate 3, insulating plate 4 and end plate 5 are arranged in this order. A tension plate (not shown) is arranged outside each end plate 5, and these tension plates are bolted to the end plates 5 so that a predetermined compressive force is applied in the stacking direction of the cells 10. It has become.

  As shown in FIG. 2, the unit cell 10 includes an electrolyte membrane 11, an electrode catalyst layer 12 provided on both surfaces of the electrolyte membrane 11, a diffusion layer 13 disposed outside the catalyst layer 12, a reactive gas flow path. The separator 14 is provided with a seal member 15, the sealing member 15 that seals between the diffusion layer 13 and the separator 14, and the like.

The electrolyte membrane 11 is composed of an ion exchange membrane made of a solid polymer material, and has a function of moving hydrogen ions supplied from the fuel gas from the anode side electrode to the cathode side electrode. The catalyst layer 12 is a sheet-like molded body on which an electrode catalyst such as platinum is supported, and is joined to the electrolyte membrane 11 to constitute an anode side electrode and a cathode side electrode. When hydrogen (H ₂ ) supplied from the fuel gas reaches the catalyst layer 12, it dissociates into two hydrogen atoms (hydrogen active species: H ^* ) that are active on the surface of the catalyst. Furthermore, an oxidation reaction proceeds on the catalyst surface, and hydrogen ions (H ⁺ ) and electrons (e ⁻ ) are generated from the hydrogen active species. Among these, hydrogen ions are transferred into the electrolyte membrane 11. In the catalyst layer 12, by appropriately setting the blending ratio of the catalyst and the solid electrolyte, it is possible to improve the battery performance while suppressing a decrease in catalyst utilization efficiency.

  The electrolyte membrane 11 and the catalyst layer 12 in the present embodiment both have a rectangular shape in plan view, and the electrolyte membrane 11 has a larger area than the catalyst layer 12 as shown in FIGS. Yes. Further, the electrolyte membrane 11 in the present embodiment has lower rigidity than the diffusion layer 13. Therefore, when the electrolyte membrane 11, the catalyst layer 12, and the diffusion layer 13 are joined by pressure bonding, as shown in FIG. 3, a recess 11 a is provided on the surface of the electrolyte membrane 11, and the catalyst layer 12 is embedded in the recess 11 a. It becomes a state. Thereby, the boundary vicinity part (area | region A in FIG.2 and FIG.3) of the electrolyte membrane 11 and the peripheral part 12a of the catalyst layer 12 is made into a substantially plane.

  The diffusion layer 13 is made of a porous material such as carbon cloth or carbon paper, and diffuses the reaction gas supplied from the outside of the fuel cell 1 to the catalyst layer 12 via the separator 14 and flows to the catalyst layer 12. It has a function. The diffusion layer 13 also has a conductive function for conducting the catalyst layer 12 and the separator 14. The diffusion layer 13 in the present embodiment has a rectangular shape in plan view, and has an area smaller than the electrolyte membrane 11 and larger than the catalyst layer 12 as shown in FIGS. Further, the surface opposite to the catalyst layer 12 of the diffusion layer 13 in this embodiment is subjected to water repellent treatment.

  A membrane / electrode assembly (hereinafter referred to as “MEA”) composed of the electrolyte membrane 11 and the catalyst layer 12 is an embodiment of the laminate according to the present invention. A membrane / electrode / diffusion layer assembly (hereinafter referred to as “MEGA”) 20 including the electrolyte membrane 11, the catalyst layer 12, and the diffusion layer 13 is also an embodiment of the laminate according to the present invention.

  The separator 14 is a boundary that separates the stacked unit cells 10, and has a function of preventing a short circuit between the unit cells 10 due to the contact between the anode side electrode and the cathode side electrode between the adjacent unit cells 10. And a function of electrically connecting adjacent unit cells 10 to each other. The separator 14 is disposed adjacent to the MEGA 20, and as shown in FIG. 2, a reaction gas channel 14 a is formed on the surface facing the diffusion layer 13. The separator 14 is provided with a manifold 14b that serves as an inlet and an outlet for the reaction gas, and the manifold 14b communicates with the reaction gas channel 14a. The separator 14 preferably has characteristics such as high electron conductivity, excellent corrosion resistance, and no release of metal ions in a gas atmosphere. Examples of the material having such characteristics include carbonaceous materials such as carbon and metal materials such as stainless steel.

  Next, a method for manufacturing the MEGA 20 included in the fuel cell 1 according to this embodiment will be described.

  First, the electrolyte membrane 11 is prepared (electrolyte membrane preparation process). Next, the catalyst layer 12 is formed by applying a paste mixture obtained by mixing platinum particles and carbon particles in a predetermined solvent on both surfaces of the electrolyte membrane 11 and drying the mixture (catalyst layer forming step). These electrolyte membrane 11 and catalyst layer 12 constitute an MEA.

  Next, carbon cloth, carbon paper, or the like that becomes the diffusion layer 13 is adjacently disposed on both surfaces of the MEA, and is diffused into the electrolyte membrane 11 and the catalyst layer 12 by performing hot pressing on the entire surface of the diffusion layer 13 at a specific temperature and pressure. The MEGA 20 is configured by pressure bonding the layer 13 (pressure bonding process).

  In the pressure bonding step, a recess 11a is provided on the surface of the electrolyte membrane 11, and the catalyst layer 12 is embedded in the recess 11a so that the vicinity of the boundary between the electrolyte membrane 11 and the peripheral portion 12a of the catalyst layer 12 (FIGS. 2 and 2). The hot pressing is performed under the condition that the area A) in FIG.

  Since the catalyst layer 12 constituting the MEA has a smaller area than the electrolyte membrane 11 as shown in FIG. 2, the peripheral portion of the MEA is composed only of the electrolyte membrane 11. The thickness is thinner than the central portion composed of the electrolyte membrane 11 and the catalyst layer 12. For this reason, if the diffusion layer 13 is simply pressure-bonded to the MEA, a gap is formed between the electrolyte membrane 11 and the diffusion layer 13 along the peripheral edge portion 12 a of the catalyst layer 12. In the present embodiment, conditions for reducing the void volume as much as possible (conditions in which the region A in the vicinity of the boundary between the electrolyte membrane 11 and the peripheral edge portion 12a of the catalyst layer 12 is substantially flat) I am going to do a hot press.

  FIG. 4A is a graph showing the relationship between the temperature T during hot pressing under a constant pressure and the volume V of the void formed in the peripheral edge portion 12a of the catalyst layer 12. As shown in this graph, it is known that when the pressure during hot pressing is constant, the volume V of the air gap decreases as the temperature T increases. FIG. 4B is a graph showing the relationship between the pressure P at the time of hot pressing at a constant temperature and the volume V of the void formed in the peripheral edge portion 12a of the catalyst layer 12. As shown in this graph, it is known that when the temperature during hot pressing is constant, the volume V of the air gap decreases as the pressure P increases.

  Accordingly, in the present embodiment, the correlation between the temperature T (pressure P) and the void volume V as shown in FIG. 4 and the material characteristics of the electrolyte membrane 11, the catalyst layer 12, and the diffusion layer 13 ( The conditions (temperature and pressure at the time of hot pressing) to be adopted in the crimping process are determined by comprehensively considering the rigidity, composition change, melting temperature, etc.) and thickness.

For example, when the electrolyte membrane 11 having a thickness of t ₁ μm and the diffusion layer 13 having a thickness of t ₂ mm are employed, the temperature at the time of hot pressing is set to T _{1 to} T ₂ ° C., and the pressure is set to P _1. By setting it to ~ P ₂ MPa, the vicinity of the boundary between the electrolyte membrane 11 and the peripheral edge portion 12a of the catalyst layer 12 is made substantially flat. Here, T ₁ , T ₂ , P ₁ , and P ₂ are values determined from the thickness (t ₁ , t ₂ ) and material characteristics of the electrolyte membrane 11 and the diffusion layer 13.

  The MEGA 20 is manufactured through the above process group (electrolyte membrane preparation process, catalyst layer forming process, and pressure bonding process). One embodiment of the diffusion layer bonding step in the present invention is included in the crimping step in the present embodiment. The unit cell 10 can be configured by sandwiching the MEGA 20 with the separator 14 via the seal member 15. A plurality of unit cells 10 configured as described above are stacked to form the stack body 2, and the current collector plate 3, the insulating plate 4 and the end plate 5 are disposed at the end of the stack body 2. The fuel cell 1 can be obtained by bolting the tension plate.

  In the method for manufacturing the laminate (MEGA 20) according to the embodiment described above, the vicinity of the boundary (region A) between the electrolyte membrane 11 and the peripheral edge portion 12a of the catalyst layer 12 can be made substantially flat, so that the catalyst layer 12 It is possible to prevent the generated water from collecting on the peripheral edge portion 12a. As a result, chemical degradation of the electrolyte membrane 11 can be suppressed, so that the durability of the electrolyte membrane 11 can be improved and the power generation efficiency of the fuel cell 1 can be increased.

Second Embodiment
Next, a fuel cell according to a second embodiment of the present invention will be described with reference to FIG. The fuel cell according to the present embodiment is obtained by changing the configuration of the MEGA 20 of the fuel cell 1 according to the first embodiment, and other configurations are substantially the same as those of the first embodiment. For this reason, it demonstrates centering around the changed structure, and attaches | subjects the code | symbol same about the part which is common in 1st Embodiment, and abbreviate | omits the description.

  As shown in FIG. 5, the MEGA 20A included in the fuel cell according to the present embodiment is disposed on the outside of the electrolyte membrane 11A, the electrode catalyst layer 12 provided on both surfaces of the electrolyte membrane 11A, and the catalyst layer 12. It is composed of a diffusion layer 13A and the like. Since the catalyst layer 12 is substantially the same as that described in the first embodiment, the description thereof is omitted.

  11 A of electrolyte membranes in this embodiment are comprised from the solid polymer material ion exchange membrane similarly to the electrolyte membrane 11 in 1st Embodiment, and move the hydrogen ion supplied from fuel gas from an anode side electrode to a cathode side electrode It has a function to make it. The diffusion layer 13A in the present embodiment is made of a porous material such as carbon cloth or carbon paper like the diffusion layer 13 in the first embodiment, and is supplied from the outside of the fuel cell to the catalyst layer 12 side via a separator. A function of diffusing the reacted gas to flow through the catalyst layer 12 and a conductive function of conducting the catalyst layer 12 and the separator. The shapes of the electrolyte membrane 11A and the diffusion layer 13A are the same as the shapes of the electrolyte membrane 11 and the diffusion layer 13 in the first embodiment.

  The electrolyte membrane 11A in the present embodiment has higher rigidity than the diffusion layer 13A. Therefore, when the electrolyte membrane 11A, the catalyst layer 12, and the diffusion layer 13A are joined by pressure bonding, no recess is provided on the surface of the electrolyte membrane 11A, and as shown in FIG. 5, the diffusion layer 13A on the catalyst layer 12 side is not provided. A recess 13Aa is provided on the surface, and the catalyst layer 12 is buried in the recess 13Aa. Thereby, the boundary vicinity part (area | region B in FIG. 5) of 13 A of diffusion layers and the peripheral part 12a of the catalyst layer 12 is made into a substantially plane. The MEGA 20A including the electrolyte membrane 11A, the catalyst layer 12, and the diffusion layer 13A is an embodiment of the laminate according to the present invention.

  Next, a method for manufacturing MEGA 20A according to this embodiment will be described.

  First, the electrolyte membrane 11A is prepared (electrolyte membrane preparation step). Next, the catalyst layer 12 is formed by applying a paste-like mixture in which platinum particles and carbon particles are mixed in a predetermined solvent to both surfaces of the electrolyte membrane 11A and drying the catalyst layer 12 (catalyst layer forming step). Next, carbon cloth, carbon paper, or the like that becomes the diffusion layer 13A is disposed adjacent to both surfaces of the electrolyte membrane 11A, and hot pressing is performed on the entire surface of the diffusion layer 13A at a specific temperature and pressure, whereby the electrolyte membrane 11A and the catalyst layer 12 are obtained. The diffusion layer 13A is pressure bonded to the MEGA 20A to form a pressure bonding process.

  In this crimping step, a recess 13Aa is provided on the surface of the diffusion layer 13A, and the catalyst layer 12 is embedded in the recess 13Aa so that the vicinity of the boundary between the diffusion layer 13A and the peripheral edge 12a of the catalyst layer 12 (region in FIG. 5). Hot pressing is performed under the condition that B) is substantially flat. At this time, the correlation between the temperature T (pressure P) and the void volume V as shown in FIG. 4 and the material characteristics (stiffness, composition change, melting) of the electrolyte membrane 11A, the catalyst layer 12 and the diffusion layer 13A are shown. The conditions (temperature and pressure at the time of hot pressing) to be adopted in the crimping process are determined by comprehensively considering the temperature and the like) and the thickness.

For example, when an electrolyte membrane 11A having a thickness of t ₃ μm and a diffusion layer 13A having a thickness of t ₄ mm are employed, the temperature during hot pressing is set to T _{3 to} T ₄ ° C. and the pressure is set to P ₃ By setting to ~ P ₄ MPa, the vicinity of the boundary between the diffusion layer 13A and the peripheral edge portion 12a of the catalyst layer 12 is made to be substantially flat. Here, T ₃ , T ₄ , P ₃ , and P ₄ are values determined from the thickness (t ₃ , t ₄ ) and material characteristics of the electrolyte membrane 11A and the diffusion layer 13A.

  The MEGA 20A is manufactured through the above process group (electrolyte membrane preparation process, catalyst layer forming process, and pressure bonding process). One embodiment of the diffusion layer bonding step in the present invention is included in the crimping step in the present embodiment.

  In the laminated body (MEGA 20A) according to the embodiment described above, the vicinity of the boundary (region B) between the diffusion layer 13A and the peripheral edge 12a of the catalyst layer 12 is substantially flat, and therefore the peripheral edge 12a of the catalyst layer 12 is. It is possible to suppress the generation water from being accumulated (between the electrolyte membrane 11A and the diffusion layer 13A). As a result, chemical deterioration of the electrolyte membrane 11A can be suppressed, so that the durability of the electrolyte membrane 11A can be improved and the power generation efficiency of the fuel cell can be increased.

<Third Embodiment>
Next, a fuel cell according to a third embodiment of the present invention will be described with reference to FIG. The fuel cell according to the present embodiment is obtained by changing the configuration of the MEGA 20 of the fuel cell 1 according to the first embodiment, and other configurations are substantially the same as those of the first embodiment. For this reason, it demonstrates centering around the changed structure, and attaches | subjects the code | symbol same about the part which is common in 1st Embodiment, and abbreviate | omits the description.

  As shown in FIG. 6, the MEGA 20B included in the fuel cell according to the present embodiment is disposed on the outside of the electrolyte membrane 11B, the electrode catalyst layer 12 provided on both surfaces of the electrolyte membrane 11B, and the catalyst layer 12. It is composed of a diffusion layer 13B and the like. Since the catalyst layer 12 is substantially the same as that described in the first embodiment, the description thereof is omitted.

  The electrolyte membrane 11B in the present embodiment is composed of an ion exchange membrane made of a solid polymer material like the electrolyte membrane 11 in the first embodiment, and moves hydrogen ions supplied from the fuel gas from the anode side electrode to the cathode side electrode. It has a function to make it. The diffusion layer 13B in the present embodiment is made of a porous material such as carbon cloth or carbon paper like the diffusion layer 13 in the first embodiment, and is supplied from the outside of the fuel cell to the catalyst layer 12 side via a separator. A function of diffusing the reacted gas to flow through the catalyst layer 12 and a conductive function of conducting the catalyst layer 12 and the separator. The shapes of the electrolyte membrane 11B and the diffusion layer 13B are the same as the shapes of the electrolyte membrane 11 and the diffusion layer 13 in the first embodiment.

  The electrolyte membrane 11B in the present embodiment has the same rigidity as the diffusion layer 13B. Accordingly, when the electrolyte membrane 11B, the catalyst layer 12, and the diffusion layer 13B are pressure-bonded, the recess 11Ba is provided on the surface of the electrolyte membrane 11B as shown in FIG. 6, and the recess 13Ba is also provided on the surface of the diffusion layer 13b. Provided. And the catalyst layer 12 whole (especially peripheral part 12a) is filled in the space formed by these recessed parts 11Ba and 13Ba opposingly arranged. In addition, MEGA20B which consists of electrolyte membrane 11B, the catalyst layer 12, and the diffusion layer 13B is one Embodiment of the laminated body which concerns on this invention.

  Next, the manufacturing method of MEGA20B which concerns on this embodiment is demonstrated.

  First, the electrolyte membrane 11B is prepared (electrolyte membrane preparation step). Next, the catalyst layer 12 is formed by applying and drying a paste-like mixture obtained by mixing platinum particles and carbon particles in a predetermined solvent on both surfaces of the electrolyte membrane 11B (catalyst layer forming step). Next, a carbon cloth, carbon paper, or the like that becomes the diffusion layer 13B is adjacently disposed on both surfaces of the electrolyte membrane 11B, and hot pressing is performed on the entire surface of the diffusion layer 13B at a specific temperature and pressure, whereby the electrolyte membrane 11B and the catalyst layer 12 are performed. The diffusion layer 13B is pressure bonded to the MEGA 20B (pressure bonding process).

  In this crimping step, the recess 11Ba is provided on the surface of the electrolyte membrane 11B, and the recess 13Ba is provided on the surface of the diffusion layer 13B, and the entire catalyst layer 12 is filled in the space formed by these recesses 11Ba and 13Ba facing each other. Hot press is performed under such conditions. At this time, the correlation between the temperature T (pressure P) and the void volume V as shown in FIG. 4 and the material characteristics (stiffness, composition change, melting) of the electrolyte membrane 11B, the catalyst layer 12 and the diffusion layer 13B are shown. The conditions (temperature and pressure at the time of hot pressing) to be adopted in the crimping process are determined by comprehensively considering the temperature and the like) and the thickness.

For example, when an electrolyte membrane 11B having a thickness of t ₅ μm and a diffusion layer 13B having a thickness of t ₆ mm are employed, the temperature during hot pressing is set to T _{5 to} T ₆ ° C. and the pressure is set to P ₅ Set to ~ P ₆ MPa. Here, T ₅ , T ₆ , P ₅ , and P ₆ are numerical values determined from the thickness (t ₅ , t ₆ ) and material characteristics of the electrolyte membrane 11B and the diffusion layer 13b. The MEGA 20B is manufactured through the above process group (electrolyte membrane preparation process, catalyst layer forming process, and pressure bonding process).

  In the laminate (MEGA 20B) according to the embodiment described above, the entire catalyst layer 12 (particularly, the peripheral portion 12a) is formed in the space formed by the recesses 11Ba and 13Ba provided on the surface of the electrolyte membrane 11B and the surface of the diffusion layer 13B. Therefore, it is possible to prevent the generated water from accumulating in the peripheral edge portion 12a of the catalyst layer 12 (between the electrolyte membrane 11B and the diffusion layer 13B). As a result, chemical deterioration of the electrolyte membrane 11B can be suppressed, so that the durability of the electrolyte membrane 11B can be improved and the power generation efficiency of the fuel cell can be increased.

  In each of the above embodiments, an example in which a MEGA is manufactured by forming a catalyst layer on the surface of the electrolyte membrane and then joining the diffusion layer to the electrolyte membrane has been shown. However, the surface of the diffusion layer on the electrolyte membrane side is shown. The MEGA can also be manufactured through a process of forming a catalyst layer on the substrate to form a diffusion electrode and bonding the diffusion electrode to the electrolyte membrane.

  Further, in each of the above embodiments, the MEGA is manufactured by pressure bonding the electrolyte membrane, the catalyst layer, and the diffusion layer. At this time, pressure bonding using a hot press machine having a heating and pressing roller ( (Roller pressure bonding) may be performed, and pressure bonding (flat plate pressure bonding) using a hot press machine having a press plate may be performed.

  Further, in each of the above embodiments, an example was shown in which MEGA was manufactured by pressure bonding the electrolyte membrane, the catalyst layer, and the diffusion layer by performing hot pressing over the entire surface of the diffusion layer. It is also possible to manufacture MEGA by pressure bonding the electrolyte membrane, the catalyst layer, and the diffusion layer by performing hot pressing in a part (region corresponding to the vicinity of the peripheral edge of the catalyst layer).

  Further, in each of the above embodiments, the example in which the concave portion is provided in the electrolyte membrane and / or the diffusion layer so that the entire catalyst layer is embedded and filled has been described. However, the entire catalyst layer is not necessarily embedded and filled. It is not necessary to provide a concave portion, but a concave portion is provided so that at least the periphery of the catalyst layer is embedded, and the vicinity of the boundary between the electrolyte membrane (diffusion layer) and the peripheral portion of the catalyst layer is made substantially flat, It is also possible to reduce the volume of the gap at the peripheral edge.

  Further, in each of the above embodiments, an example in which the areas of both catalyst layers (anode electrode catalyst layer and cathode electrode catalyst layer) formed on both surfaces of the electrolyte membrane are the same is shown. The area of the layer and the area of the catalyst layer for the cathode electrode can be made different. For example, the area of the cathode electrode catalyst layer is made smaller than the area of the anode electrode catalyst layer (the position of the peripheral edge of the cathode electrode catalyst layer is closer to the center than the position of the peripheral edge of the anode electrode catalyst layer). This is preferable because the lifetime of MEGA can be extended.

1 is a perspective view showing a fuel cell according to a first embodiment of the present invention. It is a disassembled perspective view of the single cell which comprises the fuel cell shown in FIG. It is sectional drawing of MEGA contained in the single battery shown in FIG. (A) is a graph which shows the relationship between the volume of the space | gap formed in the inside of MEGA shown in FIG. 3, and the temperature at the time of a hot press, (b) is formed in the inside of MEGA shown in FIG. It is a graph which shows the relationship between the volume of the space | gap and the pressure at the time of a hot press. It is sectional drawing of MEGA contained in the fuel cell which concerns on 2nd Embodiment of this invention. It is sectional drawing of MEGA contained in the fuel cell which concerns on 3rd Embodiment of this invention. It is sectional drawing of MEGA manufactured with the conventional manufacturing method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 11 * 11A * 11B ... Electrolyte membrane, 11a * 11Ba ... Recessed part, 12 ... Catalyst layer, 12a ... Peripheral part, 13 * 13A * 13B ... Diffusion layer, 13Aa * 13Ba ... Recessed part, 20 * 20A * 20B ... MEGA (laminate)

Claims (9)

A laminate comprising an electrolyte membrane, a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane, and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer,
The laminated body comprised so that the boundary vicinity of the said diffusion layer and the peripheral part of the said catalyst layer may become a substantially plane. A recess is provided on the surface of the diffusion layer on the catalyst layer side,
The laminate according to claim 1, wherein at least a peripheral portion of the catalyst layer is embedded in the concave portion of the diffusion layer. A laminate comprising an electrolyte membrane, a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane, and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer,
The surface of the electrolyte membrane and the surface of the diffusion layer on the catalyst layer side are each provided with a recess, and these recesses are opposed to each other to form a space, and at least the peripheral portion of the catalyst layer is formed in this space. Laminated body filled with The catalyst layer is an anode electrode catalyst layer and a cathode electrode catalyst layer,
The laminate according to any one of claims 1 to 3, wherein an area of the anode electrode catalyst layer and an area of the cathode electrode catalyst layer are different from each other.   A fuel cell comprising the laminate according to any one of claims 1 to 4. A method for producing a laminate comprising an electrolyte membrane and a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane,
The manufacturing method of a laminated body including the crimping | compression-bonding process of crimping | bonding on the conditions that the boundary vicinity of the said electrolyte membrane and the peripheral part of the said catalyst layer becomes a substantially plane.   The said crimping | compression-bonding process is a manufacturing method of the laminated body of Claim 6 including the diffusion layer joining process of joining a diffusion layer to the both surfaces of the said electrolyte membrane via the said catalyst layer. A method for producing a laminate comprising: an electrolyte membrane; a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane; and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer,
The manufacturing method of the laminated body including the crimping | compression-bonding process of crimping | bonding on the conditions that the boundary vicinity of the said diffusion layer and the peripheral part of the said catalyst layer becomes a substantially plane. A method for producing a laminate comprising: an electrolyte membrane; a catalyst layer for electrodes provided on both surfaces of the electrolyte membrane; and a diffusion layer bonded to both surfaces of the electrolyte membrane via the catalyst layer,
The surface of the electrolyte membrane and the surface of the diffusion layer to which the catalyst layer is joined are provided with recesses, and the recesses are arranged to face each other to form a space, and at least the periphery of the catalyst layer in the space The manufacturing method of the laminated body including the crimping | compression-bonding process which crimps | bonds on the conditions which fill a part.

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