JP2014192095A - Membrane electrode assembly and solid polymer fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane electrode assembly capable of enhancing durability, and a solid polymer fuel cell.SOLUTION: A membrane electrode assembly 10A includes an electrolyte layer 11, a fuel electrode catalyst layer 12 in contact with the electrolyte layer 11, and an air electrode catalyst layer 13 in contact with the electrolyte layer 11. The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are arranged on the same side with respect to the electrolyte layer 11 in the thickness direction of the electrolyte layer 11. The electrolyte layer 11 has a flat surface 11a, and the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are arranged on the flat surface 11a.

Description

  The technology of the present disclosure relates to a membrane electrode assembly and a polymer electrolyte fuel cell including the membrane electrode assembly.

  In recent years, fuel cells that directly convert the reaction energy of a raw material gas into electric energy have attracted attention. A polymer electrolyte fuel cell, which is a type of fuel cell, uses a polymer electrolyte membrane as an electrolyte. FIG. 16 is a cross-sectional view showing an example of the structure of a polymer electrolyte fuel cell.

  As shown in FIG. 16, the polymer electrolyte membrane 110 is sandwiched between a catalyst layer 120A constituting the fuel electrode and a catalyst layer 120C constituting the air electrode. The membrane electrode assembly 100 composed of the polymer electrolyte membrane 110 and the two catalyst layers 120A and 120C is sandwiched between a pair of separators 130A and 130C. Between the polymer electrolyte membrane 110 and the separators 130A and 130C, gaskets 140A and 140C that suppress leakage of gas supplied to the catalyst layers 120A and 120C are disposed around the catalyst layers 120A and 120C. Fuel gas containing hydrogen is supplied to the catalyst layer 120A on the fuel electrode side from a gas flow path formed in the separator 130A. An oxidant gas containing oxygen is supplied to the catalyst layer 120C on the air electrode side from a gas flow path formed in the separator 130C. And an electromotive force arises between a fuel electrode and an air electrode when fuel gas and oxidant gas advance electrode reaction in presence of a catalyst.

  In the above configuration, the gaskets 140A and 140C are disposed around the catalyst layers 120A and 120C on the front and back surfaces of the polymer electrolyte membrane 110, respectively. Therefore, the edges of the catalyst layers 120A and 120C and the edges of the gaskets 140A and 140C in contact with the edges of the catalyst layers 120A and 120C are arranged on the surface of the polymer electrolyte membrane 110. Here, the separators 130 </ b> A and 130 </ b> C fasten the membrane electrode assembly 100 from both sides in the thickness direction of the membrane electrode assembly 100 in order to sandwich the membrane electrode assembly 100. Therefore, the force that the polymer electrolyte membrane 110 receives from the separators 130A and 130C concentrates on the edges of the catalyst layers 120A and 120C and the edges of the gaskets 140A and 140C and the portions where the polymer electrolyte membrane 110 contacts. As a result, since the pressure applied to the polymer electrolyte membrane 110 is locally concentrated, the polymer electrolyte membrane 110 is liable to be crushed or broken, and the durability of the membrane electrode assembly 100 is lowered.

  In contrast to the above configuration, there has been proposed a membrane electrode assembly in which a fuel electrode side catalyst layer and an air electrode side catalyst layer are formed in different sizes (see, for example, Patent Documents 1 and 2). According to such a configuration, the position where the edge of the catalyst layer contacts the polymer electrolyte membrane on the surface of the polymer electrolyte membrane, and the position where the edge of the catalyst layer contacts the polymer electrolyte membrane on the back surface of the polymer electrolyte membrane. However, they do not face each other across the polymer electrolyte membrane. Therefore, since the position where the pressure applied to the polymer electrolyte membrane is concentrated differs between the front and back of the polymer electrolyte membrane, the concentration of pressure is alleviated.

JP 2006-338938 A JP 2007-242609 A

  By the way, in recent years, in order to improve the power generation performance of the solid polymer fuel cell under low humidification conditions, the polymer electrolyte membrane has been made thinner. As a result, the mechanical strength of the polymer electrolyte membrane tends to be low. Therefore, since the polymer electrolyte membrane is easily crushed or broken due to the pressure applied to the polymer electrolyte membrane from the separator, further improvement in the durability of the membrane electrode assembly is required.

  An object of the technology of the present disclosure is to provide a membrane electrode assembly and a polymer electrolyte fuel cell capable of enhancing durability.

  One aspect of the membrane electrode assembly in the technology of the present disclosure includes an electrolyte layer, a fuel electrode catalyst layer in contact with the electrolyte layer, and an air electrode catalyst layer in contact with the electrolyte layer, and the fuel electrode catalyst layer And the air electrode catalyst layer are disposed on the same side of the electrolyte layer in the thickness direction of the electrolyte layer.

  According to the said structure, two types of catalyst layers contact an electrolyte layer on the same side with respect to an electrolyte layer in the thickness direction of an electrolyte layer. Therefore, when the electrolyte layer receives pressure from the separator in the polymer electrolyte fuel cell, a position where the pressure is concentrated is formed only on one side of the electrolyte layer in the thickness direction of the electrolyte layer. As a result, compared to the case where the pressure concentration positions are formed on both sides of the electrolyte layer in the thickness direction of the electrolyte layer, the electrolyte layer is prevented from being crushed or broken. Therefore, the durability of the membrane electrode assembly is enhanced.

In another aspect of the membrane electrode assembly in the technology of the present disclosure, the electrolyte layer includes a flat surface, and the fuel electrode catalyst layer and the air electrode catalyst layer are disposed on the flat surface.
According to the said structure, two types of catalyst layers are arrange | positioned on the same flat surface with which an electrolyte layer is provided. Therefore, the durability of the membrane electrode assembly can be enhanced with a simple configuration.

  In another aspect of the membrane electrode assembly according to the technology of the present disclosure, the electrolyte layer includes a step surface, and the convex portion of the step surface is disposed between the fuel electrode catalyst layer and the air electrode catalyst layer. Has been.

  According to the said structure, two types of catalyst layers are arrange | positioned on both sides of a convex part in the level | step difference surface with which an electrolyte layer is provided. Accordingly, mixing of gas between the fuel electrode catalyst layer and the air electrode catalyst layer can be suppressed.

  Another aspect of the membrane electrode assembly in the technology of the present disclosure further includes a base material that supports the electrolyte layer, and the base material is the fuel in the thickness direction of the electrolyte layer with respect to the electrolyte layer. It arrange | positions on the opposite side to the electrode catalyst layer and the said air electrode catalyst layer.

  According to the said structure, an electrolyte layer is supported by the base material from the opposite side to two types of catalyst layers in the thickness direction of an electrolyte layer. Therefore, wrinkles and folds are prevented from occurring in the electrolyte layer. As a result, the reliability of the membrane electrode assembly is improved.

  Another aspect of the membrane electrode assembly in the technology of the present disclosure further includes a base material that supports the fuel electrode catalyst layer and the air electrode catalyst layer, and the base material is in a thickness direction of the electrolyte layer. The fuel electrode catalyst layer and the air electrode catalyst layer are disposed on the same side of the electrolyte layer.

  According to the above configuration, the fuel electrode catalyst layer and the air electrode catalyst layer are supported on the base material from the same side as the catalyst layer with respect to the electrolyte layer in the thickness direction of the electrolyte layer. Therefore, the electrolyte layer is supported by the base material via the fuel electrode catalyst layer and the air electrode catalyst layer. Therefore, wrinkles and folds are prevented from occurring in the electrolyte layer. As a result, the reliability of the membrane electrode assembly is improved.

  Another aspect of the membrane electrode assembly in the technology of the present disclosure further includes a gas seal portion that suppresses the flow of gas, and the gas seal portion is disposed between the fuel electrode catalyst layer and the air electrode catalyst layer. Has been.

According to the above configuration, since the gas seal portion is disposed between the fuel electrode catalyst layer and the air electrode catalyst layer, it is possible to suppress the gas supplied to each of the two types of catalyst layers from being mixed.
In another aspect of the membrane electrode assembly in the technology of the present disclosure, a gas flow path through which a gas flows is formed between the fuel electrode catalyst layer and the air electrode catalyst layer.

  According to the above configuration, since the gas flow path is formed between the fuel electrode catalyst layer and the air electrode catalyst layer, the diffusibility of the gas supplied to each of the two types of catalyst layers is enhanced. Moreover, the drainage property of the water produced | generated by electric power generation is improved.

One aspect of the polymer electrolyte fuel cell according to the technology of the present disclosure includes the membrane electrode assembly.
According to the above configuration, by providing the membrane electrode assembly with improved durability, the durability of the polymer electrolyte fuel cell is improved, and long-term operation is possible.

    According to the technique of the present disclosure, the durability of the membrane electrode assembly can be enhanced.

Sectional drawing which shows the cross-section of the membrane electrode assembly of 1st Embodiment in the technique of this indication. The top view which shows the planar structure of the membrane electrode assembly of 1st Embodiment. Sectional drawing which shows the cross-section of the polymer electrolyte fuel cell of 1st Embodiment. The top view which shows the planar structure of the polymer electrolyte fuel cell of 1st Embodiment. Sectional drawing which shows the cross-section of the membrane electrode assembly of 2nd Embodiment in the technique of this indication. A cross-sectional structure of a polymer electrolyte fuel cell according to a second embodiment, which is a polymer electrolyte fuel cell using a membrane electrode assembly that does not include a base material that supports a fuel electrode catalyst layer and an air electrode catalyst layer. FIG. 2 shows a cross-sectional structure of a polymer electrolyte fuel cell according to a second embodiment, which is a polymer electrolyte fuel cell using a membrane electrode assembly including a base material that supports a fuel electrode catalyst layer and an air electrode catalyst layer. Sectional drawing. Sectional drawing which shows the cross-section of the membrane electrode assembly of 3rd Embodiment in the technique of this indication. Sectional drawing which shows the cross-section of the polymer electrolyte fuel cell of 3rd Embodiment. Sectional drawing which shows the cross-section of the membrane electrode assembly of 4th Embodiment in the technique of this indication. Sectional drawing which shows the cross-section of the polymer electrolyte fuel cell of 4th Embodiment. The top view which shows the planar structure of the membrane electrode assembly of a modification. The top view which shows the planar structure of the membrane electrode assembly of a modification. The top view which shows the planar structure of the membrane electrode assembly which applied the membrane electrode assembly of the modification to 4th Embodiment. The top view which shows the planar structure of the polymer electrolyte fuel cell which applied the membrane electrode assembly of the modification to 4th Embodiment. Sectional drawing which shows the cross-section of the conventional polymer electrolyte fuel cell.

(First embodiment)
With reference to FIGS. 1-4, 1st Embodiment of a membrane electrode assembly and a polymer electrolyte fuel cell is described.

First, the configuration of the membrane electrode assembly will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, a membrane electrode assembly 10A includes a polymer electrolyte membrane 11 as an electrolyte layer, a fuel electrode catalyst layer 12 and an air electrode catalyst layer 13 laminated on the polymer electrolyte membrane 11, and a polymer. And a base material 14 that supports the electrolyte membrane 11.

  The polymer electrolyte membrane 11 includes two flat surfaces 11 a and 11 b as the front and back surfaces of the polymer electrolyte membrane 11. The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are in contact with the polymer electrolyte membrane 11 on one flat surface 11a. The substrate 14 and the polymer electrolyte membrane 11 are in contact with each other on the other flat surface 11b. That is, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are disposed on the same side of the polymer electrolyte membrane 11 in the thickness direction of the polymer electrolyte membrane 11. The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are in contact with the polymer electrolyte membrane 11 on the same flat surface 11a. The base material 14 is disposed on the opposite side of the polymer electrolyte membrane 11 from the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 in the thickness direction of the polymer electrolyte membrane 11.

  As shown in FIG. 2, the planar shape of the polymer electrolyte membrane 11 is smaller than the planar shape of the substrate 14. The upper surface of the base material 14 is exposed outside the edge of the polymer electrolyte membrane 11.

  One fuel electrode catalyst layer 12 and one air electrode catalyst layer 13 are arranged on the flat surface 11a. A gap is provided between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. A flat surface 11 a of the polymer electrolyte membrane 11 is exposed in the gap between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. The edge of the fuel electrode catalyst layer 12 that does not face the edge of the air electrode catalyst layer 13 overlaps the edge of the polymer electrolyte membrane 11. The edge of the air electrode catalyst layer 13 that does not face the edge of the fuel electrode catalyst layer 12 overlaps the edge of the polymer electrolyte membrane 11.

A method for producing the membrane electrode assembly 10A will be described.
First, the polymer electrolyte membrane 11 is formed on the base material 14. As the film formation method, a known film formation method such as coating formation is used.

  As the material of the base material 14, a material that has excellent adhesion to the electrolyte and does not corrode the electrolyte is used. Examples of the material of the substrate 14 include a metal plate such as gold or stainless steel, a resin film such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyamide, polyphenylene sulfide, polyether ether ketone, polypropylene, polyethylene, or polyimide. Is mentioned.

  The polymer electrolyte membrane 11 may be any membrane having ion conductivity. Examples of the material of the polymer electrolyte membrane 11 include hydrocarbon resins such as fluorine resins such as Nafion (manufactured by DuPont, registered trademark), engineering plastics, or resins obtained by introducing sulfonic acid groups into engineering plastic copolymers. Based resins and the like.

  Next, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are formed on the polymer electrolyte membrane 11. As a film forming method, a known film forming method can be used as long as the adhesion between the catalyst layers 12 and 13 and the polymer electrolyte membrane 11 is good. For example, after the catalyst layer forming slurry containing the constituent materials of the catalyst layers 12 and 13 is applied onto the polymer electrolyte membrane 11, the catalyst layers 12 and 13 are formed by drying the catalyst layer slurry. The Examples of coating methods include doctor blade coating, dipping coating, slit coating, die coating, spraying, screen printing, flexographic printing, offset printing, dispenser printing, ink jet printing, or gravure printing. Law. Examples of the drying method include hot air drying, IR (infrared) drying, and reduced pressure drying.

  The catalyst layers 12 and 13 include an electrolyte and catalyst particles. As the electrolyte, in order to improve the adhesion between the catalyst layers 12 and 13 and the polymer electrolyte membrane 11, it is preferable to use an electrolyte of the same quality as the electrolyte contained in the polymer electrolyte membrane 11. Examples of catalyst particles include platinum group elements such as platinum, palladium, ruthenium, iridium, rhodium, or osmium, iron, lead, copper, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium, aluminum, etc. Examples thereof include metals, alloys of these metals, oxides, and double oxides. In particular, it is preferable to use platinum or a platinum alloy as the catalyst particles.

  The particle size of the catalyst particles is preferably from 0.5 nm to 20 nm, more preferably from 1 nm to 5 nm. If the particle size of the catalyst particles is too large, the activity of the catalyst is lowered. Moreover, when the particle size of the catalyst particles is too small, the stability of the catalyst is lowered.

  As the catalyst particles, single catalyst particles may be used, or catalyst particles supported on a conductive carrier may be used. It is preferable to use catalyst particles supported on a conductive carrier. Carbon particles are used as the conductive carrier. The carbon particles may be fine particles that have conductivity and are not affected by the catalyst. Examples of the carbon particles include carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotube, or fullerene. The particle size of the carbon particles is preferably 10 nm or more and 1000 nm or less, and more preferably 10 nm or more and 100 nm or less. If the particle size of the carbon particles is too small, it is difficult to form an electron conduction path. Also. If the particle size of the carbon particles is too large, the catalyst layer becomes thick, so that the resistance increases and the output characteristics of the polymer electrolyte fuel cell are degraded.

  As the solvent for the catalyst layer slurry, a solvent capable of dispersing or dissolving the electrolyte is used. Examples of the solvent include water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, and other alcohols, acetone, methyl ethyl ketone, and methyl propyl ketone. , Ketones such as methylbutylketone, methylisobutylketone, methylamylketone, pentanone, heptanone, cyclohexanone, methylcyclohexanone, acetonylacetone, diethylketone, dipropylketone, or diisobutylketone, tetrahydrofuran, tetrahydropyran, Ethers such as dioxane, diethylene glycol dimethyl ether, anisole, methoxytoluene, diethyl ether, dipropyl ether, or dibutyl ether; Amines such as isopropylamine, butylamine, isobutylamine, cyclohexylamine, diethylamine, or aniline, propyl formate, isobutyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, acetic acid Examples thereof include esters such as isopentyl, methyl propionate, ethyl propionate, and butyl propionate. Other examples of the solvent include acetic acid, propionic acid, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and the like. Examples of glycol solvents and glycol ether solvents include ethylene glycol, diethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diacetone alcohol, 1-methoxy-2-propanol, -Ethoxy-2-propanol etc. are mentioned.

Instead of the above-described method, the membrane electrode assembly 10A may be formed by pasting the laminated body of the polymer electrolyte membrane 11 and the catalyst layers 12 and 13 previously prepared on the base material 14.
Next, the configuration of the polymer electrolyte fuel cell will be described with reference to FIGS. 3 and 4. FIG. 4 is a plan view of the polymer electrolyte fuel cell, and shows the positions of the current collector and the gas flow path with broken lines.

  As shown in FIG. 3, the polymer electrolyte fuel cell 20 </ b> A includes a membrane electrode assembly 10 </ b> A, a fuel electrode current collector 22 laminated on the fuel electrode catalyst layer 12, and a gas electrode catalyst layer 13. And an air electrode current collector 23. Further, the polymer electrolyte fuel cell 20 </ b> A includes a separator 21 that holds the membrane electrode assembly 10 </ b> A and the current collectors 22 and 23. A fuel electrode gas flow path 24 is defined by the fuel electrode catalyst layer 12, the fuel electrode current collector 22, and the separator 21. An air electrode gas flow path 25 is defined by the air electrode catalyst layer 13, the air electrode current collector 23, and the separator 21.

  The fuel electrode gas flow path 24 is in contact with the surface of the fuel electrode catalyst layer 12 opposite to the polymer electrolyte membrane 11. The fuel electrode current collector 22 is in contact with a portion of the surface of the fuel electrode catalyst layer 12 opposite to the polymer electrolyte membrane 11 where the fuel electrode gas flow path 24 is not disposed. A fuel electrode is composed of the fuel electrode current collector 22 and the fuel electrode catalyst layer 12.

  The air electrode gas flow path 25 is in contact with the surface of the air electrode catalyst layer 13 opposite to the polymer electrolyte membrane 11. The air electrode current collector 23 is in contact with a portion of the air electrode catalyst layer 13 on the side opposite to the polymer electrolyte membrane 11 where the air electrode gas flow path 25 is not disposed. The air electrode current collector 23 and the air electrode catalyst layer 13 constitute an air electrode.

  The separator 21 is covered on the polymer electrolyte membrane 11, the catalyst layers 12 and 13, and the current collectors 22 and 23 on the base material 14. The separator 21 is disposed on the catalyst layers 12 and 13 and extends in the surface direction of the membrane electrode assembly 10A, and the thickness of the membrane electrode assembly 10A from the upper plate portion 21a toward the substrate 14. An intermediate plate portion 21b and a side plate portion 21c extending in the direction are provided.

  In the upper plate portion 21 a of the separator 21, a groove that partitions the fuel electrode gas flow path 24 is formed at a position facing the fuel electrode catalyst layer 12 exposed between the fuel electrode current collectors 22. That is, the fuel electrode gas flow path 24 penetrates the fuel electrode current collector 22 and bites into the separator 21 between the fuel electrode catalyst layer 12 and the separator 21. The fuel gas is supplied to the fuel electrode catalyst layer 12 by flowing the fuel gas through the fuel electrode gas flow path 24.

  Further, the upper plate portion 21 a of the separator 21 is formed with a groove that partitions the air electrode gas flow path 25 at a position facing the air electrode catalyst layer 13 exposed between the air electrode current collectors 23. . That is, the air electrode gas flow path 25 penetrates the separator 21 through the air electrode current collector 23 between the air electrode catalyst layer 13 and the separator 21. The oxidant gas is supplied to the air electrode catalyst layer 13 by causing the oxidant gas to flow through the air electrode gas flow path 25.

  The middle plate portion 21 b of the separator 21 fills the gap between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. Thereby, mixing of gas between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 is suppressed.

  The side plate portion 21 c of the separator 21 surrounds the polymer electrolyte membrane 11 and the catalyst layers 12 and 13 outside the edge portion of the polymer electrolyte membrane 11. The side plate portion 21 c is in contact with the edge portion of the polymer electrolyte membrane 11, the edge portions of the catalyst layers 12 and 13, and the upper surface of the base material 14.

  As shown in FIG. 4, the fuel electrode gas flow path 24 penetrates the polymer electrolyte fuel cell 20A on the fuel electrode catalyst layer 12 in the surface direction of the membrane electrode assembly 10A. The air electrode gas flow path 25 penetrates the polymer electrolyte fuel cell 20A on the air electrode catalyst layer 13 in the surface direction of the membrane electrode assembly 10A. In addition, the number of the fuel electrode gas flow paths 24 and the air electrode gas flow paths 25 should just be one or more.

  The catalyst layers 12 and 13 and the separator 21 are assembled to the membrane electrode assembly 10A, and a fuel gas and oxidant gas supply mechanism and the like are provided to manufacture a single-cell solid polymer fuel cell 20A. Is done. The polymer electrolyte fuel cell 20A is used in a single cell state or in a state where a plurality of polymer electrolyte fuel cells 20A are combined.

  In addition, after the formation of the membrane electrode assembly 10A, the substrate 14 that is a substrate at the time of forming the polymer electrolyte membrane 11 may be removed from the membrane electrode assembly 10A. In this case, in the polymer electrolyte fuel cell 20A, the membrane electrode assembly 10A composed of the polymer electrolyte membrane 11 and the catalyst layers 12 and 13 is different from the base material when the polymer electrolyte membrane 11 is formed. Arranged on the substrate.

The operation of the membrane electrode assembly 10A and the polymer electrolyte fuel cell 20A of the first embodiment will be described.
The polymer electrolyte membrane 11 receives pressure from the separator 21 when the separator 21 presses the membrane electrode assembly 10 </ b> A. The pressure received by the polymer electrolyte membrane 11 is concentrated on the surface of the polymer electrolyte membrane 11 where the edges of the catalyst layers 12 and 13 are in contact with the polymer electrolyte membrane 11. Here, in the membrane electrode assembly 10 </ b> A, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are disposed on the same side of the polymer electrolyte membrane 11 in the thickness direction of the polymer electrolyte membrane 11. Yes. Therefore, the position where the pressure is concentrated is formed only on one side in the thickness direction of the polymer electrolyte membrane 11. For this reason, deformation of the polymer electrolyte membrane 11 that causes the polymer electrolyte membrane 11 to be crushed or broken occurs only on one surface of the polymer electrolyte membrane 11. As a result, positions where pressure is concentrated on both sides in the thickness direction of the polymer electrolyte membrane 11 are formed as in the conventional case, and the polymer electrolyte membrane 11 is deformed on both sides of the polymer electrolyte membrane 11 as compared with the conventional case. As a result, the polymer electrolyte membrane 11 can be prevented from being crushed or broken. Therefore, the durability of the membrane electrode assembly 10A is enhanced. As a result of enhancing the durability of the membrane electrode assembly 10A, the durability of the polymer electrolyte fuel cell 20A is enhanced, and long-term operation is possible.

  In general, since the polymer electrolyte membrane 11 has low rigidity, the polymer electrolyte membrane 11 is likely to be wrinkled or broken. In this regard, in the first embodiment, when the membrane electrode assembly 10 </ b> A includes the base material 14, the polymer electrolyte membrane 11 is supported by the base material 14. The occurrence of wrinkles and creases is suppressed. In the membrane electrode assembly in which the two catalyst layers sandwiching the polymer electrolyte membrane are formed in different sizes as in the prior art, in particular, the polymer electrolyte membrane is likely to be wrinkled or broken. On the other hand, in 1st Embodiment, durability of 10 A of membrane electrode assemblies can be improved, suppressing the wrinkles and bending of the polymer electrolyte membrane 11. FIG. Therefore, the reliability of the membrane electrode assembly 10A is improved.

  Further, the base material 14 which is a base material at the time of forming the polymer electrolyte membrane 11 is used as a constituent member of the polymer electrolyte fuel cell 20A. Therefore, compared with a case where a new base material on which the membrane electrode assembly 10A is disposed is used in the polymer electrolyte fuel cell 20A, materials necessary for manufacturing the polymer electrolyte fuel cell 20A are reduced. . In addition, the manufacturing process of the polymer electrolyte fuel cell 20A is simplified.

As described above, according to the first embodiment, the following effects can be obtained.
(1) The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are disposed on the same side of the polymer electrolyte membrane 11 in the thickness direction of the polymer electrolyte membrane 11. As a result, since the position where the pressure is concentrated is formed only on one side in the thickness direction of the polymer electrolyte membrane 11, compared to the case where the two catalyst layers are arranged with the polymer electrolyte membrane interposed therebetween, The durability of the membrane electrode assembly 10A is enhanced.

  (2) The polymer electrolyte membrane 11 is supported on the base material 14 from the side opposite to the catalyst layers 12 and 13. Therefore, the polymer electrolyte membrane 11 can be prevented from wrinkling or breaking, and the reliability of the membrane electrode assembly 10A can be improved.

  (3) The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are in contact with the polymer electrolyte membrane 11 on the same flat surface 11a. Therefore, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 can be arranged on the same side in the thickness direction of the polymer electrolyte membrane 11 with a simple configuration. As a result, the degree of freedom in forming the polymer electrolyte membrane 11 and the catalyst layers 12 and 13 is increased.

(Second Embodiment)
With reference to FIGS. 5-7, 2nd Embodiment of a membrane electrode assembly and a polymer electrolyte fuel cell is demonstrated centering on difference with 1st Embodiment. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

First, the structure of the membrane electrode assembly will be described with reference to FIG.
As shown in FIG. 5, the membrane electrode assembly 30 includes a polymer electrolyte membrane 31, a fuel electrode catalyst layer 12 and an air electrode catalyst layer 13 laminated on the polymer electrolyte membrane 31, a fuel electrode catalyst layer 12 and And a base material 34 that supports the air electrode catalyst layer 13.

  The polymer electrolyte membrane 31 includes a step surface 31 a on one side in the thickness direction of the polymer electrolyte membrane 31. The polymer electrolyte membrane 31 includes a flat surface 31 b on the other side in the thickness direction of the polymer electrolyte membrane 31. The fuel electrode catalyst layer 12, the air electrode catalyst layer 13, and the polymer electrolyte membrane 31 are in contact with each other at the step surface 31a. That is, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are disposed on the same side of the polymer electrolyte membrane 31 in the thickness direction of the polymer electrolyte membrane 31.

  The step surface 31 a has a convex portion 32 that protrudes in the thickness direction of the polymer electrolyte membrane 31 from the other portion of the step surface 31 a. In the polymer electrolyte membrane 31, the thickness of the portion where the convex portion 32 is formed is thicker than the thickness of the other portion. The convex portion 32 is disposed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are in contact with the convex portion 32. That is, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are arranged on the step surface 31a with the convex portion 32 interposed therebetween.

  The base material 34 is disposed on the same side as the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 with respect to the polymer electrolyte membrane 31 in the thickness direction of the polymer electrolyte membrane 31. The base material 34 is in contact with the surface opposite to the polymer electrolyte membrane 31 in the fuel electrode catalyst layer 12 in the thickness direction. The base material 34 is in contact with the surface opposite to the polymer electrolyte membrane 31 in the air electrode catalyst layer 13 in the thickness direction. The base material 34 is in contact with the upper surface of the convex portion 32 sandwiched between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13.

  The planar shapes of the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are the same as the planar shapes of the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 of the first embodiment shown in FIG. That is, the edge of the fuel electrode catalyst layer 12 that is not in contact with the protrusion 32 overlaps the edge of the polymer electrolyte membrane 31. Further, the edge of the air electrode catalyst layer 13 that is not in contact with the convex portion 32 overlaps with the edge of the polymer electrolyte membrane 31.

A method for manufacturing the membrane electrode assembly 30 will be described.
First, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are formed on the substrate 34. As the material of the base material 34 and the catalyst layers 12 and 13, the same material as that of the base material 14 and the catalyst layers 12 and 13 exemplified in the first embodiment is used. As the method for forming the catalyst layers 12 and 13, the same method as the method for forming the catalyst layers 12 and 13 exemplified in the first embodiment is used.

  Next, the polymer electrolyte membrane 31 is formed on the base material 34 on which the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are formed. As the material of the polymer electrolyte membrane 31, the same material as the material of the polymer electrolyte membrane 11 exemplified in the first embodiment is used. As the method for forming the polymer electrolyte membrane 31, the same method as the method for forming the polymer electrolyte membrane 11 exemplified in the first embodiment is used.

  Alternatively, the membrane / electrode assembly 30 may be formed by pasting the laminated body of the catalyst layers 12 and 13 and the polymer electrolyte membrane 31 previously prepared on the base material 34. In addition, after the formation of the membrane electrode assembly 30, the base material 34 that is a base material at the time of forming the polymer electrolyte membrane 31 may be removed from the membrane electrode assembly 30.

Subsequently, the configuration of the polymer electrolyte fuel cell will be described with reference to FIGS. 6 and 7.
First, the case where the base material 34 is removed from the membrane electrode assembly 30 and the membrane electrode assembly 30 is composed of the polymer electrolyte membrane 31 and the catalyst layers 12 and 13 will be described with reference to FIG.

  As shown in FIG. 6, the polymer electrolyte fuel cell 40 </ b> A is different from the polymer electrolyte fuel cell 20 </ b> A of the first embodiment in a portion sandwiched between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. The configuration is different.

  A convex portion 32 of the polymer electrolyte membrane 31 is disposed at a portion sandwiched between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. Compared with the polymer electrolyte fuel cell 20A of the first embodiment, the length in the thickness direction of the middle plate portion 41b of the separator 41 is shortened by the thickness of the convex portion 32.

  In the manufacturing process of the polymer electrolyte fuel cell 40A, the membrane electrode assembly 30 is disposed on the base member 44, and the catalyst layers 12 and 13 and the separator are placed on the membrane electrode assembly 30 disposed on the base member 44. 41 is assembled.

Next, with reference to FIG. 7, the case where the membrane electrode assembly 30 includes the base material 34 will be described.
As shown in FIG. 7, in the polymer electrolyte fuel cell 40 </ b> B, a fuel electrode current collector 35 and a fuel electrode gas flow path 37 are disposed in a portion of the base material 34 facing the fuel electrode catalyst layer 12. ing. An air electrode current collector 36 and an air electrode gas flow path 38 are disposed in a portion of the substrate 34 that faces the air electrode catalyst layer 13.

The separator 42 covers the membrane electrode assembly 30 including the base material 34. Unlike the polymer electrolyte fuel cell 20A of the first embodiment, the separator 42 does not have an intermediate plate portion.
The current collectors 35 and 36 and the gas flow paths 37 and 38 are provided in advance on the base material 34. A laminate of the catalyst layers 12 and 13 and the polymer electrolyte membrane 31 is bonded to the base material 34 provided with the current collectors 35 and 36 and the gas flow paths 37 and 38 to form the membrane electrode assembly 30. Is done. In the manufacturing process of the polymer electrolyte fuel cell 40B, the membrane electrode assembly 30 is disposed on the base material 44, and the separator 42 is assembled to the membrane electrode assembly 30 disposed on the base material 44.

  Thus, if the base material 34 is provided with the current collectors 35 and 36 and the gas flow paths 37 and 38, the membrane electrode assembly 30 having the base material 34 is used to form a solid polymer type. The fuel cell 40B can be formed.

The operation of the membrane electrode assembly 30 and the polymer electrolyte fuel cells 40A and 40B of the second embodiment will be described.
Also in the membrane electrode assembly 30 of the second embodiment, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are on the same side with respect to the polymer electrolyte membrane 31 in the thickness direction of the polymer electrolyte membrane 31. Is arranged. Therefore, the position where the pressure is concentrated is formed only on one side in the thickness direction of the polymer electrolyte membrane 31. As a result, compared to the case where the two catalyst layers are arranged with the polymer electrolyte membrane interposed therebetween, the polymer electrolyte membrane 11 can be prevented from being crushed and broken, so that the durability of the membrane electrode assembly 30 is improved. .

  Further, the convex portion of the polymer electrolyte membrane 31 is disposed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. Accordingly, a wide contact area between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 and the polymer electrolyte membrane 31 can be secured. Further, mixing of gas between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 is suppressed.

  Further, when the membrane electrode assembly 30 has the base material 34, the polymer electrolyte membrane 31 is supported on the base material 34 via the catalyst layers 12 and 13. Therefore, the polymer electrolyte membrane 11 can be prevented from being wrinkled or broken, so that the reliability of the membrane electrode assembly 30 is improved.

As described above, according to the second embodiment, in addition to the effect (1) of the first embodiment, the following effect can be obtained.
(4) The polymer electrolyte membrane 31 is supported on the base material 34 from the same side as the catalyst layers 12 and 13. Accordingly, the polymer electrolyte membrane 31 can be prevented from wrinkling and folding, so that the reliability of the membrane electrode assembly 30 is improved.

  (5) The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are disposed on the step surface 31 a of the polymer electrolyte membrane 31, and the convex portion 32 of the step surface 31 a is formed by the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. It is arranged between. Accordingly, a wide contact area between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 and the polymer electrolyte membrane 31 can be secured. Further, mixing of gas between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 is suppressed.

(Third embodiment)
With reference to FIG. 8 and FIG. 9, the third embodiment of the membrane electrode assembly and the polymer electrolyte fuel cell will be described with a focus on differences from the first embodiment. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  First, the configuration of the membrane electrode assembly will be described with reference to FIG. The configuration between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 is different between the membrane electrode assembly 10B of the third embodiment and the membrane electrode assembly 10A of the first embodiment.

  As shown in FIG. 8, a gas seal portion 15 is provided between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 on the flat surface 11 a of the polymer electrolyte membrane 11. The fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 are in contact with the gas seal portion 15.

  As the material of the gas seal portion 15, a material that suppresses gas permeation is used. Examples of the material of the gas seal portion 15 include rubbers such as silicone rubber, ethylene-propylene-diene rubber, or nitrile butadiene rubber, silicone elastomers, thermoplastic elastomers, thermosetting elastomers, or UV curing. Examples thereof include resins.

  The gas seal portion 15 is formed by disposing the above material between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 alone. Alternatively, the gas seal unit 15 applies a coating solution prepared by dissolving the above materials in a solvent between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13, and performs drying and curing as necessary. It is formed.

Next, the configuration of the polymer electrolyte fuel cell will be described with reference to FIG.
As shown in FIG. 9, the polymer electrolyte fuel cell 20B is different from the polymer electrolyte fuel cell 20A of the first embodiment in a portion sandwiched between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. The configuration is different.

  A gas seal portion 15 is disposed at a portion sandwiched between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. Unlike the polymer electrolyte fuel cell 20A of the first embodiment, the separator 26 does not have an intermediate plate portion.

The operation of the membrane electrode assembly 10B and the polymer electrolyte fuel cell 20B of the third embodiment will be described.
Generally, when the fuel gas and the oxidant gas react with each other, hydrogen peroxide is generated and the durability of the membrane electrode assembly is lowered. In the third embodiment, a gas seal portion 15 is provided between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. Therefore, the fuel gas supplied to the fuel electrode catalyst layer 12 and the oxidant gas supplied to the air electrode catalyst layer 13 come into contact with each other between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 to cause a reaction. It is suppressed.

  Moreover, since the member which suppresses gas mixing is arrange | positioned at the membrane electrode assembly 10B, it is not necessary to provide the separator 26 with the member which suppresses gas mixing. Therefore, the configuration of the separator 26 is simplified. Further, in the manufacturing process of the polymer electrolyte fuel cell 20B, it is easy to align the separator 26 and the membrane electrode assembly 10B.

As described above, according to the third embodiment, in addition to the effects (1) to (3) of the first embodiment, the following effects can be obtained.
(6) Since the gas seal portion 15 is disposed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13, mixing of gases supplied to each of the two types of catalyst layers is suppressed.

(Fourth embodiment)
With reference to FIG. 10 and FIG. 11, the fourth embodiment of the membrane electrode assembly and the polymer electrolyte fuel cell will be described focusing on the differences from the third embodiment. In addition, the same code | symbol is attached | subjected about the structure similar to 3rd Embodiment, and the description is abbreviate | omitted.

  First, the configuration of the membrane electrode assembly will be described with reference to FIG. The configuration of the periphery of the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 is different between the membrane electrode assembly 10C of the fourth embodiment and the membrane electrode assembly 10B of the third embodiment.

  As shown in FIG. 10, a space Sa is formed between the fuel electrode catalyst layer 12 and the gas seal portion 15 on the flat surface 11 a of the polymer electrolyte membrane 11. On the flat surface 11 a of the polymer electrolyte membrane 11, a space Sb is formed between the air electrode catalyst layer 13 and the gas seal portion 15.

  If the edge of the fuel electrode catalyst layer 12 opposite to the edge facing the gas seal portion 15 is the edge 12e, the edge 12e is disposed on the inner side of the edge of the polymer electrolyte membrane 11. The flat surface 11a of the polymer electrolyte membrane 11 is exposed outside the edge portion 12e. That is, on the flat surface 11a of the polymer electrolyte membrane 11, a space Sc is formed outside the edge portion 12e.

  Assuming that the edge of the air electrode catalyst layer 13 opposite to the edge facing the gas seal part 15 is the edge 13e, the edge 13e is arranged on the inner side of the edge of the polymer electrolyte membrane 11. The flat surface 11a of the polymer electrolyte membrane 11 is exposed outside the edge portion 13e. That is, on the flat surface 11a of the polymer electrolyte membrane 11, a space Sd is formed outside the edge portion 13e.

  In the above configuration, the spaces Sa and Sc formed around the fuel electrode catalyst layer 12 in the surface direction on the flat surface 11 a of the polymer electrolyte membrane 11 form the fuel electrode gas flow path 16. The fuel electrode gas flow path 16 is in contact with the edge of the fuel electrode catalyst layer 12 around the fuel electrode catalyst layer 12. On the flat surface 11 a of the polymer electrolyte membrane 11, spaces Sb and Sd formed around the air electrode catalyst layer 13 in the surface direction form an air electrode gas flow path 17. The air electrode gas flow path 17 is in contact with the edge of the air electrode catalyst layer 13 around the air electrode catalyst layer 13.

  In other words, the fuel electrode gas flow path 16 is formed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13 and on the opposite side of the air electrode catalyst layer 13 with respect to the fuel electrode catalyst layer 12. . The air electrode gas flow path 17 is formed between the air electrode catalyst layer 13 and the fuel electrode catalyst layer 12 and on the side opposite to the fuel electrode catalyst layer 12 with respect to the air electrode catalyst layer 13.

Next, the configuration of the polymer electrolyte fuel cell will be described with reference to FIG.
As shown in FIG. 11, in the polymer electrolyte fuel cell 20 </ b> C, the fuel electrode current collector 27 is in contact with the entire surface of the fuel electrode catalyst layer 12 on the side opposite to the polymer electrolyte membrane 11. The air electrode current collector 28 is in contact with the entire surface of the air electrode catalyst layer 13 opposite to the polymer electrolyte membrane 11.

Unlike the polymer electrolyte fuel cell 20B of the third embodiment, the upper plate portion 29a of the separator 29 does not have a groove at a position facing the current collectors 27 and 28.
In the portion where the space Sa is formed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13, the upper plate portion 29a of the separator 29, the fuel electrode catalyst layer 12, the gas seal portion 15, and the polymer electrolyte membrane. 11 divides the fuel electrode gas flow path 16. In a portion where the space Sc is formed on the side opposite to the air electrode catalyst layer 13 with respect to the fuel electrode catalyst layer 12, the upper plate portion 29a, the side plate portion 29c of the separator 29, the fuel electrode catalyst layer 12, and the polymer electrolyte. A fuel electrode gas flow path 16 is defined by the membrane 11.

  In the portion where the space Sb is formed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13, the upper plate portion 29a of the separator 29, the air electrode catalyst layer 13, the gas seal portion 15, and the polymer electrolyte membrane. 11 divides the air electrode gas flow path 17. In the portion where the space Sd is formed on the side opposite to the fuel electrode catalyst layer 12 with respect to the air electrode catalyst layer 13, the upper plate portion 29a, the side plate portion 29c of the separator 29, the air electrode catalyst layer 13, and the polymer electrolyte. The air electrode gas flow path 17 is partitioned by the membrane 11.

The operation of the membrane electrode assembly 10C and the polymer electrolyte fuel cell 20C of the fourth embodiment will be described.
Since the gas flow paths 16 and 17 are in contact with the edges of the catalyst layers 12 and 13, the diffusibility of the gas supplied to the catalyst layers 12 and 13 is enhanced. As a result, gas can be efficiently supplied to the catalyst layers 12 and 13. Moreover, since the water produced | generated by the electric power generation is drained from the edge part of the air electrode catalyst layer 13 to the gas flow path 17, the drainage property of produced water is improved. The output of the polymer electrolyte fuel cell 20C is improved by improving the gas diffusibility and the drainage of the generated water.

  Further, since the gas flow paths 16 and 17 are formed in the membrane electrode assembly 10C, it is not necessary to provide the separator 29 with a groove for partitioning the gas flow path. Therefore, the configuration of the separator 29 is simplified. Further, in the manufacturing process of the polymer electrolyte fuel cell 20C, the alignment between the separator 29 and the membrane electrode assembly 10C is facilitated.

As described above, according to the fourth embodiment, in addition to the effects (1) to (3) of the first embodiment and the effect (6) of the third embodiment, the following effects can be obtained.
(7) Since the gas flow paths 16 and 17 are formed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13, the diffusibility of the gas supplied to the catalyst layers 12 and 13 is enhanced. Moreover, the drainage of produced water is improved.

(Modification)
The above embodiment can be implemented with the following modifications.
The membrane electrode assembly may include a plurality of fuel electrode catalyst layers and a plurality of air electrode catalyst layers. For example, as shown in FIG. 12, a plurality of fuel electrode catalyst layers 52 and a plurality of air electrode catalyst layers 53 may be arranged in a matrix in the membrane electrode assembly 10D. The fuel electrode catalyst layer 52 and the air electrode catalyst layer 53 are adjacent to each other in the vertical direction of the array, and the fuel electrode catalyst layer 52 and the air electrode catalyst layer 53 are adjacent to each other in the horizontal direction of the array. For example, as illustrated in FIG. 13, in the membrane electrode assembly 10 </ b> E, a plurality of fuel electrode catalyst layers 62 and a plurality of air electrode catalyst layers 63 extending in one direction may be alternately arranged. Further, the fuel electrode catalyst layer and the air electrode catalyst layer may be formed in a shape different from a rectangle.

  14 and 15 are plan views of a membrane electrode assembly 10F and a polymer electrolyte fuel cell 20F to which the arrangement of the catalyst layer shown in FIG. 13 is applied to the fourth embodiment. FIG. 15 is a plan view of the polymer electrolyte fuel cell 20F, and the position of the current collector is indicated by a broken line.

  As shown in FIG. 14, a gas seal portion 65 is disposed between each of the fuel electrode catalyst layer 62 and the air electrode catalyst layer 63. A fuel electrode gas flow channel 66 is formed between each of the fuel electrode catalyst layer 62 and the gas seal portion 65. An air electrode gas passage 67 is formed between the air electrode catalyst layer 63 and the gas seal portion 65. The fuel electrode gas flow channel 66 is also formed outside the fuel electrode catalyst layer 62 disposed at the end of the fuel electrode catalyst layer 62 and the air electrode catalyst layer 63 in the juxtaposed direction. The air electrode gas flow path 67 is also formed outside the air electrode catalyst layer 63 disposed at the end of the fuel electrode catalyst layer 62 and the air electrode catalyst layer 63 in the juxtaposed direction.

  As shown in FIG. 15, the anode current collector 68 in contact with each anode electrode catalyst layer 62 is connected to each other at one end in the direction in which the anode electrode catalyst layer 62 extends. The air electrode current collector 69 in contact with each air electrode catalyst layer 63 is connected to each other at one end in the direction in which the air electrode catalyst layer 63 extends.

  Thus, if the membrane electrode assembly is configured to include a plurality of fuel electrode catalyst layers and a plurality of air electrode catalyst layers, depending on the arrangement of each catalyst layer and the configuration of the peripheral circuit, the polymer electrolyte fuel cell The degree of freedom regarding output adjustment is improved.

  In the embodiment and the modification, the distance between the fuel electrode catalyst layer and the air electrode catalyst layer is 1 μm or more and 800 μm or less in order to suppress a decrease in output of the polymer electrolyte fuel cell due to an increase in the resistance of the polymer electrolyte membrane. It is preferable that The distance between the fuel electrode catalyst layer and the air electrode catalyst layer is preferably as small as possible in the range of 1 μm to 800 μm. Specifically, the distance between the fuel electrode catalyst layer and the air electrode catalyst layer is preferably 1 μm to 500 μm, more preferably 1 μm to 300 μm, and even more preferably 1 μm to 20 μm. If the distance between the fuel electrode catalyst layer and the air electrode catalyst layer is less than 1 μm, formation of the catalyst layer becomes difficult.

  The thickness of the polymer electrolyte membrane in the portion where the fuel electrode catalyst layer is in contact with the thickness of the polymer electrolyte membrane in the portion where the air electrode catalyst layer is in contact may be different. In short, it is only necessary that the fuel electrode catalyst layer and the air electrode catalyst layer are disposed on the same side of the polymer electrolyte membrane in the thickness direction of the polymer electrolyte membrane.

  -You may combine 4th Embodiment with 1st Embodiment. For example, a space is provided between the middle plate portion 21 b of the separator 21, the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13, and a gas flow path is formed between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. May be.

  In the fourth embodiment, the gas flow paths 16 and 17 may be formed only between the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13. Gas flow paths may also be formed on the surfaces of the fuel electrode catalyst layer 12 and the air electrode catalyst layer 13.

  -In 1st-3rd embodiment, the separator does not need to be provided with the side-plate part. That is, the separator may cover only the upper part of the membrane electrode assembly without surrounding the edge of the polymer electrolyte membrane.

  -You may form a gas flow path from the material which has air permeability. Examples of the air permeable material include carbon paper, carbon cloth, or carbon non-woven fabric.

  10A to 10F, 30 ... membrane electrode assembly, 11, 31 ... polymer electrolyte membrane, 11a, 11b, 31b ... flat surface, 12, 52, 62 ... fuel electrode catalyst layer, 13, 53, 63 ... air electrode side catalyst Layer, 14, 34, 44 ... base material, 15, 65 ... gas seal part, 16, 24, 37, 66 ... fuel electrode gas flow path, 17, 25, 38, 67 ... air electrode gas flow path, 22, 27 , 35, 68 ... fuel electrode current collector, 23, 28, 36, 69 ... air electrode current collector, 21, 26, 29, 41, 42 ... separator, 31a ... step surface, 32 ... convex portion.

Claims (8)

An electrolyte layer;
A fuel electrode catalyst layer in contact with the electrolyte layer;
An air electrode catalyst layer in contact with the electrolyte layer,
The fuel electrode catalyst layer and the air electrode catalyst layer,
The membrane / electrode assembly is disposed on the same side of the electrolyte layer in the thickness direction of the electrolyte layer. The electrolyte layer has a flat surface,
The fuel electrode catalyst layer and the air electrode catalyst layer,
The membrane electrode assembly according to claim 1, wherein the membrane electrode assembly is disposed on the flat surface. The electrolyte layer includes a step surface,
The membrane electrode assembly according to claim 1, wherein a convex portion of the step surface is disposed between the fuel electrode catalyst layer and the air electrode catalyst layer. Further comprising a substrate for supporting the electrolyte layer;
The substrate is
The membrane electrode assembly according to claim 2, wherein the membrane electrode assembly is disposed on a side opposite to the fuel electrode catalyst layer and the air electrode catalyst layer with respect to the electrolyte layer in a thickness direction of the electrolyte layer. Further comprising a base material that supports the fuel electrode catalyst layer and the air electrode catalyst layer;
The substrate is
The membrane electrode assembly according to claim 3, wherein the membrane electrode assembly is disposed on the same side as the fuel electrode catalyst layer and the air electrode catalyst layer with respect to the electrolyte layer in a thickness direction of the electrolyte layer. A gas seal part that suppresses gas flow is further provided,
The membrane electrode assembly according to claim 2 or 4, wherein the gas seal portion is disposed between the fuel electrode catalyst layer and the air electrode catalyst layer. The membrane electrode assembly according to any one of claims 2, 4, and 6, wherein a gas flow path through which a gas flows is formed between the fuel electrode catalyst layer and the air electrode catalyst layer. A polymer electrolyte fuel cell comprising the membrane electrode assembly according to any one of claims 1 to 7.

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