JP5301928B2 - Membrane electrode assembly, membrane electrode-frame assembly, and polymer electrolyte fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a membrane electrode assembly, capable of suppressing degradation of power generation efficiency by suppression of soaking of a resin material from an outer edge part to a central part of a gas diffusion layer, when a frame body is formed by resin molding adjacent to the outer edge part of the membrane electrode assembly. <P>SOLUTION: The membrane electrode assembly is constituted of a polymer electrolyte membrane; a pair of catalyst layers opposed to each other through the polymer electrolyte membrane; a pair of gas diffusion layers opposed to each other through the polymer electrolyte and the pair of catalyst layers; and a resin soaking regulating part, mounted adjacent to the outer edge part of at least one gas diffusion layer of the pair and which is capable of preventing the resin material from soaking to the gas diffusion layers, while permitting a resin material molten due to heating of partial soaking. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a membrane electrode assembly, a membrane electrode-frame assembly including the membrane electrode assembly, and a polymer electrolyte fuel cell. More specifically, the present invention relates to an improvement in the structure of the outer edge of the membrane electrode assembly.

  2. Description of the Related Art In recent years, development of polymer electrolyte fuel cells (hereinafter abbreviated as fuel cells) has been promoted as driving sources for mobile objects such as automobiles, distributed power generation systems, and household cogeneration systems.

A fuel cell is configured by sandwiching a membrane electrode-frame assembly, in which a frame is disposed so as to surround an outer edge of the membrane electrode assembly, between a pair of plate-like conductive separators. As shown in FIG. 13, the membrane electrode assembly 101 includes a polymer electrolyte membrane 111 whose outer edge is supported by the frame body, and a pair of electrode layers 112 and 112 formed on both surfaces of the polymer electrolyte membrane 111. It consists of The electrode layer 112 includes a catalyst layer 113 such as platinum formed on the surface of the polymer electrolyte membrane 111 and a gas diffusion layer 114 formed on the surface of the catalyst layer 113. The gas diffusion layer 114 is configured to have a water repellent carbon layer 114b containing a water repellent material and conductive carbon in the surface layer portion on the catalyst layer 113 side of the conductive base material 114a having a porous structure.
The fuel cell causes an electrochemical reaction by supplying a fuel gas containing hydrogen to one gas diffusion layer 114 and an oxidant gas containing oxygen such as air to the other gas diffusion layer 114. Thus, the device generates electric power and heat at the same time.

In the fuel cell having the above-described configuration, various proposals have been made for improving power generation performance for practical use. For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2007-66805), the thickness of the outer edge portion of the water-repellent carbon layer 114b is made thicker than that of the central portion in order to suppress deterioration of the polymer electrolyte membrane 111. The technology to do is disclosed.
JP 2007-66805 A

  However, in the conventional fuel cell including Patent Document 1, as shown in FIGS. 14A and 14B, when the frame body 116 is resin-molded adjacent to the outer edge portion of the membrane electrode assembly 101, it is melted by heating. There is a possibility that the resin material may permeate excessively from the outer edge of the gas diffusion layer 114 toward the center. The portion 117 infiltrated with the resin material loses gas diffusibility and does not contribute to power generation. For this reason, the power generation performance of the fuel cell decreases as the infiltrating portion 117 increases.

  Therefore, an object of the present invention is to solve the above-described problem, and suppresses the penetration of the resin material into the gas diffusion layer when the frame body is resin-molded adjacent to the outer edge portion of the membrane electrode assembly. An object of the present invention is to provide a membrane electrode assembly, a membrane electrode-frame assembly, and a polymer electrolyte fuel cell that can suppress a decrease in power generation performance.

In order to achieve the above object, the present invention is configured as follows.
According to a first aspect of the present invention, a polymer electrolyte membrane;
A pair of catalyst layers facing each other across the polymer electrolyte membrane;
A pair of gas diffusion layers facing each other across the polymer electrolyte membrane and the pair of catalyst layers;
The resin material disposed adjacent to the outer edge of at least one gas diffusion layer of the pair of gas diffusion layers and allowing the resin material melted by heating to permeate in part, while the resin material is the gas diffusion layer A resin soaking regulation part that can be regulated so as not to soak into
I have a,
The gas diffusion layer has a water repellent carbon layer containing a water repellent material and conductive carbon on the surface layer portion on the catalyst layer side of the conductive substrate having a porous structure,
The resin soaking restriction part is configured to include the water repellent material in the conductive base material with a weight per unit area larger than a unit weight of the water repellent material included in the gas diffusion layer. Provided is a membrane electrode assembly that regulates permeation into the gas diffusion layer .

  According to a second aspect of the present invention, the thickness of the resin soaking restriction portion is greater than the thickness of the water-repellent carbon layer and is equal to or less than the thickness of the gas diffusion layer. Provide the body.

According to a third aspect of the present invention, a weight per unit area of the water-repellent material of the resin penetration restricting portion, toward the inner edge side regions in the vicinity of the gas diffusion layer is larger than the outer edge region, the first or second aspect The membrane electrode assembly described in 1. is provided.

According to a fourth aspect of the present invention, the water-repellent material of the resin penetration restricting portion, in the thickness direction parallel to the direction of the gas diffusion layer is distributed to one uniform, one second to third A membrane electrode assembly according to any one of the embodiments is provided.

According to the fifth aspect of the present invention, the gas diffusion layer has a water-repellent carbon layer containing a water-repellent material and conductive carbon on a surface layer portion of the conductive substrate having a porous structure on the catalyst layer side. And
The resin soaking restriction portion is configured to include the conductive carbon in the conductive base material with a weight per unit area larger than a unit weight of the conductive carbon included in the water-repellent carbon layer. The membrane electrode assembly according to any one of the first to fourth aspects is provided that regulates permeation of the gas diffusion layer into the gas diffusion layer.

According to a sixth aspect of the present invention, a weight per unit area of the conductive carbon of the resin penetration restricting portion, toward the inner edge side regions in the vicinity of the gas diffusion layer is larger than the outer edge region, according to the fifth aspect A membrane electrode assembly is provided.

According to a seventh aspect of the present invention, the conductive carbon of the resin penetration restricting portion, in the thickness direction parallel to the direction of the gas diffusion layer is distributed to an average, the fifth or sixth aspect The described membrane electrode assembly is provided.

According to an eighth aspect of the present invention, the membrane electrode assembly according to any one of the first to seventh aspects,
A frame formed of the resin material, disposed adjacent to the outer edge of the resin soaking restriction portion,
Provided is a membrane electrode-frame assembly in which the resin material of the frame body is soaked into the part of the resin soaking restriction portion.

According to a ninth aspect of the present invention, the membrane electrode-frame assembly according to the eighth aspect;
A pair of separators arranged to face each other across the membrane electrode-frame assembly;
A polymer electrolyte fuel cell is provided.

  According to the membrane electrode assembly, membrane electrode-frame assembly, and polymer electrolyte fuel cell according to the present invention, the resin material melted by heating soaks into the gas diffusion layer adjacent to the outer edge of the gas diffusion layer. Since the resin soaking restricting portion that can be restrained is provided, excessive permeation of the resin material from the outer edge portion to the center portion of the gas diffusion layer can be suppressed when the frame is resin-molded. Thereby, the loss of the gas diffusibility of the gas diffusion layer can be suppressed, and the deterioration of the power generation performance of the fuel cell can be suppressed as compared with the conventional case. In addition, since the resin soaking restriction part allows the resin material to soak into a part of the resin soaking restriction part, the resin soaking restriction part and the frame can be firmly joined without a gap.

Before continuing the description of the present invention, the same parts are denoted by the same reference numerals in the accompanying drawings.
The best mode for carrying out the present invention will be described below with reference to the drawings.

<< First Embodiment >>
The configuration of the membrane electrode assembly according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing an example of a basic configuration of a membrane-electrode assembly (MEA) according to the first embodiment of the present invention. The membrane electrode assembly constitutes a unit cell mounted on a polymer electrolyte fuel cell (hereinafter abbreviated as a fuel cell).

  As shown in FIG. 1, the membrane electrode assembly 1 according to the first embodiment of the present invention includes a polymer electrolyte membrane 11 that selectively transports hydrogen ions and a pair formed on both surfaces of the polymer electrolyte membrane 11. Electrode layers 12 and 12. One of the pair of electrode layers 12 and 12 is an anode electrode, and the other is a cathode electrode. Since the pair of electrode layers 12 and 12 have the same configuration, only the configuration of one electrode layer 12 will be described below unless otherwise specified.

  The electrode layer 12 includes a catalyst layer 13 such as platinum formed on the surface of the polymer electrolyte membrane 11 and a gas diffusion layer 14 formed on the surface of the catalyst layer 13. The gas diffusion layer 14 has both air permeability and electronic conductivity. Specifically, the gas diffusion layer 14 has a water repellent carbon layer 14b in which a water repellent material and conductive carbon are mixed in the surface layer portion on the catalyst layer 13 side of the conductive base material 14a having a porous structure. It is configured. In the membrane electrode assembly 1, a fuel gas containing hydrogen is supplied to one electrode layer 12 (anode electrode), and an oxidant gas containing oxygen such as air is supplied to the other electrode layer 12 (cathode electrode). As a result, an electrochemical reaction is generated, and electric power and heat can be generated simultaneously.

  The outer peripheral portion (periphery) of the gas diffusion layer 14 is configured to be able to be regulated so that the resin material melted by heating penetrates into a part of the gas diffusion layer 14 while the resin material does not penetrate the gas diffusion layer 14. A resin soaking restriction portion 15 is adjacently disposed. Specifically, the resin soaking restriction portion 15 is configured by mixing a water-repellent material and conductive carbon into the conductive base material 14a, similarly to the water-repellent carbon layer 14b. The water repellent material and the conductive carbon are included so as to have a weight per unit area larger than that of the water repellent material and the conductive carbon. In addition, the resin soaking restriction portion 15 is a region where the membrane electrode assembly 1 is not intended to mainly contribute to power generation when the membrane electrode assembly 1 is mounted on a fuel cell, for example, the membrane electrode assembly 1 is held by another member. Arranged in the area. The width | variety of the resin penetration control part 15 is about 5 mm-10 mm, for example.

  Next, the configuration, material, formation method, and the like of the polymer electrolyte membrane 11, the catalyst layer 13, the gas diffusion layer 14, and the resin soaking restriction portion 15 will be described in detail.

First, the polymer electrolyte membrane 11 will be described.
Examples of the polymer electrolyte membrane 11 according to the first embodiment include a polymer electrolyte membrane made of perfluorocarbon sulfonic acid (for example, Nafion (registered trademark) manufactured by DuPont of the United States, Aciplex (registered trademark) manufactured by Asahi Kasei Corporation). Trademark) and Gore Select (registered trademark) manufactured by Japan Gore-Tex Co., Ltd. can be used. The thickness of the polymer electrolyte membrane 11 is not particularly limited as long as the effect of the present invention is obtained.

  The polymer electrolyte constituting the polymer electrolyte membrane 11 preferably has a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, or a sulfonimide group as a cation exchange group. Of these, a polymer electrolyte having a sulfonic acid group is more preferable from the viewpoint of hydrogen ion conductivity. The polymer electrolyte having a sulfonic acid group preferably has an ion exchange capacity of 0.5 to 1.5 meq / g. When the ion exchange capacity is 0.5 meq / g or more, there is no fear that the resistance value of the obtained catalyst layer 13 increases during power generation. On the other hand, when the ion exchange capacity is 1.5 meq / g or less, the water content of the obtained catalyst layer 13 does not increase, it does not easily swell, and there is no possibility of clogging the pores. The ion exchange capacity is more preferably 0.8 to 1.2 meq / g.

The polymer electrolyte constituting the polymer electrolyte membrane _{11, CF 2 = CF- (OCF 2} CFX) m -O P - (CF 2) n-SO 3 H (m is an integer of 0 to 3, n represents an integer of 1 to 12, p represents 0 or 1, X represents a fluorine atom or a trifluoromethyl group, and a polymer unit based on a perfluorovinyl compound represented by CF ₂ = CF ₂ It is preferable that it is a perfluorocarbon copolymer containing the polymerization unit based on the tetrafluoroethylene represented by these. The fluorocarbon polymer may contain, for example, an etheric oxygen atom.

  Preferable examples of the perfluorovinyl compound include compounds represented by the following formulas (1) to (3). However, in the following formula, q represents an integer of 1 to 8, r represents an integer of 1 to 8, and t represents an integer of 1 to 3.

_{CF 2 = CFO (CF 2)} q -SO 3 H ··· (1)
_{CF 2 = CFOCF 2 CF (CF} 3) O (CF 2) r -SO 3 H ··· (2)
_{CF 2 = CF (OCF 2 CF} (CF 3)) t O (CF 2) 2 -SO 3 ··· (3)

  Moreover, the polymer electrolyte which comprises the polymer electrolyte membrane 11 may be comprised by 1 type or multiple types of polymer electrolyte, and may also contain a reinforcement body (filler) inside. The arrangement of the reinforcing bodies (for example, the degree of density or regularity) is not particularly limited. As a material constituting the reinforcing body, for example, polytetrafluoroethylene, polyfluoroalkoxyethylene, or polyphenyl sulfide can be used. Examples of the shape of the reinforcing body include a porous reinforcing body and fibril, fibrous, and spherical reinforcing body particles.

Next, the catalyst layer 13 will be described.
The catalyst layer 13 includes a catalyst-supported carbon obtained by supporting an electrode catalyst (for example, a platinum-based metal catalyst) on carbon powder, and a polymer electrolyte having hydrogen ion conductivity to be attached to the catalyst-supported carbon. .

  The carbon powder (conductive carbon particles) which is a carrier in the catalyst layer 13 is preferably a carbon material having conductive fine pores. As the carbon material, for example, carbon black, activated carbon, carbon fiber, carbon tube, and the like can be used. Examples of the carbon black include channel black, furnace black, thermal black, and acetylene black. Moreover, the activated carbon can be obtained by carbonizing and activating materials containing various carbon atoms.

The carbon powder preferably has a specific surface area of 50 to 1500 m ² / g. When the specific surface area of the carbon powder is 50 m ² / g or more, the loading ratio of the electrode catalyst is easily improved, and there is no fear that the output characteristics of the cathode side catalyst layer and the anode side catalyst layer are deteriorated. On the other hand, when the specific surface area of the carbon powder is 1500 m ² / g or less, the pores are not too fine and the coating with the polymer electrolyte becomes easier. For this reason, there is no possibility that the output characteristics of the catalyst layer 13 will deteriorate. In addition, it is more preferable that the specific surface area of carbon powder is 200-900 m < ² > / g.

  As an electrode catalyst constituting the catalyst layer 13, platinum or a platinum alloy is preferably used. Platinum alloys include platinum group metals other than platinum (ruthenium, rhodium, palladium, osmium, iridium), iron, titanium, gold, silver, chromium, manganese, molybdenum, tungsten, aluminum, silicon, rhenium, zinc, and tin. An alloy of one or more metals selected from the group and platinum is preferable. The platinum alloy may contain an intermetallic compound of platinum and the metal.

  The electrode catalyst constituting the catalyst layer 13 may be a mixture of an electrode catalyst made of platinum and an electrode catalyst made of a platinum alloy. Further, as the electrode catalyst constituting the catalyst layer 13, the same electrode catalyst or different electrode catalysts may be used on the anode side and the cathode side.

  The primary particle diameter of the electrode catalyst constituting the catalyst layer 13 is preferably 1 to 20 nm in order to make the catalyst layer 13 highly active. The primary particle size is more preferably 2 to 10 nm from the viewpoint that a large total surface area can be secured in order to increase the reaction activity.

  The catalyst supporting rate of the catalyst supporting carbon (ratio of the mass of the supported electrode catalyst to the total mass of the catalyst supporting carbon) is preferably 20 to 80% by mass. When the catalyst loading is 20% by mass or more, the required battery output can be obtained more reliably. On the other hand, when the catalyst supporting rate is 80% by mass or less, the electrode catalyst particles can be supported on the carbon powder with good dispersibility. Thereby, a catalyst effective area can be increased more. The catalyst loading is more preferably 40 to 60% by mass.

  The polymer electrolyte constituting the catalyst layer 13 may be the same type as the polymer electrolyte constituting the polymer electrolyte membrane 11 or may be a different type. For example, commercially available Nafio (registered trademark) manufactured by DuPont, Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd., and Aciplex (registered trademark) manufactured by Asahi Kasei Co., Ltd. Goods may be used.

  The polymer electrolyte constituting the catalyst layer 13 is added in proportion to the mass of the catalyst-carrying carbon in order to cover the catalyst-carrying carbon particles and secure a three-dimensional hydrogen ion conduction path. It is desirable. Specifically, the mass of the polymer electrolyte constituting the catalyst layer 13 is preferably 0.2 to 2.0 times the mass of the catalyst-supporting carbon. When the mass of the polymer electrolyte composing the catalyst layer 13 is 0.2 times or more of the mass of the catalyst-supporting carbon, sufficient hydrogen ion conductivity can be ensured. On the other hand, when the mass of the polymer electrolyte constituting the catalyst layer 13 is 2.0 times or less of the mass of the catalyst-supporting carbon, flooding can be avoided and higher battery output can be realized.

  In the first embodiment, the polymer electrolyte constituting the catalyst layer 13 only needs to be partially attached to the surface of the catalyst-carrying carbon particles (that is, at least a part of the catalyst-carrying carbon particles is formed). It is not always necessary to coat the entire catalyst-supporting carbon particles.

  The catalyst layer 13 can be formed using a plurality of inks for forming a catalyst layer prepared to have a component composition capable of realizing the configuration of the catalyst layer 13. As the dispersion medium used for preparing the ink for forming the catalyst layer, the polymer electrolyte can be dissolved or dispersible (a part of the polymer electrolyte is dissolved and the other part is dispersed without being dissolved). It is preferable to use a liquid containing an alcohol that includes a state of The dispersion medium preferably contains at least one of water, methanol, ethanol, propanol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. These water and alcohol may be used independently and may be mixed 2 or more types. As the alcohol, those having a linear structure having one OH group in the molecule are more preferred, and ethanol is particularly preferred among them. The alcohol includes those having an ether bond such as ethylene glycol monomethyl ether.

  The composition of the ink for forming the catalyst layer may be appropriately adjusted according to the configuration of the catalyst layer 13, but the solid content concentration is preferably 0.1 to 20% by mass. When the solid content concentration is 0.1% by mass or more, when the catalyst layer 13 is formed by spraying or coating the ink for forming the catalyst layer, it is desired that the catalyst layer 13 is not repeatedly sprayed or applied many times. The catalyst layer 13 having a thickness of 5 mm can be obtained. Thereby, the fall of production efficiency can be suppressed. On the other hand, when the solid content concentration is 20% by mass or less, the viscosity of the catalyst layer forming ink does not become too high, and the thickness of the catalyst layer 13 can be made substantially uniform. The solid content concentration is more preferably 1 to 10% by mass.

  The catalyst layer forming ink can be prepared based on a known method. For example, the catalyst layer forming ink can be prepared by using a method using a stirrer such as a homogenizer or a homomixer or a method using high-speed rotation such as a high-speed rotation jet flow method. The ink for forming a catalyst layer can also be prepared by using a method of applying a high pressure to extrude the dispersion from a narrow portion and applying a shearing force to the dispersion.

  As a method for forming the catalyst layer 13 using the catalyst layer forming ink, any one of a direct coating method in which the catalyst layer 13 is directly coated on the polymer electrolyte membrane 11 and an indirect coating method in which the catalyst layer 13 is indirectly coated is used. Can also be adopted. As the direct and indirect coating methods, for example, a screen printing method, a die coating method, a spray method, an ink jet method, or the like can be used. In the case of employing the indirect coating method, for example, the catalyst layer forming ink is coated on a support made of polypropylene or polyethylene terephthalate by using the coating method, and then thermally transferred, whereby the polymer electrolyte membrane 11 is coated. Thus, the catalyst layer 13 can be formed.

Next, the gas diffusion layer 14 will be described.
The conductive base material 14a constituting the gas diffusion layer 14 is produced using carbon fine powder, pore former, carbon paper, or carbon cloth having a developed structure structure in order to provide gas permeability. Can do. In addition, in order to give drainage to the conductive base material 14a, a water-repellent polymer material typified by a fluororesin may be dispersed therein. Moreover, in order to give electronic conductivity, the electroconductive base material 14a may be comprised with electron conductive materials, such as a carbon fiber, a metal fiber, or carbon fine powder.

Moreover, the electroconductive base material 14a which comprises the gas diffusion layer 14 is comprised by the woven fabric or nonwoven fabric which has a porous structure. When the conductive base material 14a is composed of the woven fabric, the thickness of the thread constituting the woven fabric is 100 to 200 μm, and the basis weight of the woven fabric is 60 to 90 g / m ^2. Is preferred. Moreover, when the electroconductive base material 14a is comprised with the said nonwoven fabric, it is preferable that the fabric weight of the said nonwoven fabric is 50-80 g / m < ² >, and the thickness of the said nonwoven fabric is 100-300 micrometers.

  The water repellent carbon layer 14b constituting the gas diffusion layer 14 is configured by mixing a water repellent material (polymer) and conductive carbon powder in the surface layer portion of the conductive base material 14a on the catalyst layer 13 side. . For the water repellent carbon layer 14b, a water repellent carbon layer ink containing a water repellent material, a conductive carbon powder, and a dispersion medium was prepared, and the ink was applied to the surface layer portion on the catalyst layer 13 side of the conductive substrate 14a. Thereafter, it can be formed by drying.

  Examples of the water repellent material include polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / A fluororesin such as ethylene copolymer (ETFE) can be used.

  As the conductive carbon powder, for example, carbon black, activated carbon, carbon fiber, and carbon tube can be used. Examples of the carbon black include channel black, furnace black, thermal black, and acetylene black.

  As the dispersion medium, the same dispersion medium as that for the catalyst layer forming ink described above can be used. Further, the composition of the water repellent carbon layer ink may be appropriately adjusted within a range not impairing the effects of the present invention.

Next, the resin soaking restriction unit 15 will be described.
As described above, the resin soaking restricting portion 15 includes the same water repellent material and conductive carbon as the water repellent carbon layer 14b on the conductive base material 14a, and the water repellent material and conductive carbon contained in the entire gas diffusion layer 14. It is comprised so that it may be included with the fabric weight larger than the fabric weight. Accordingly, the resin soaking restriction unit 15 is configured to be able to restrict the resin material soaked into the gas diffusion layer 14 while allowing the resin material melted by heating to soak into a part thereof.

  The resin soaking restriction part 15 can be efficiently produced continuously with the production of the gas diffusion layer 14 by various methods as described below.

3A and 3B show an example of a method for manufacturing the gas diffusion layer 14 and the resin soaking restriction portion 15 shown in FIG.
First, as shown in FIG. 3A, the conductive base material 14 a is placed on the plate-like jig 31 in which the holes 32 are provided at positions corresponding to the resin soaking restriction portion 15.
Next, the water repellent carbon layer ink is applied to the region of the upper surface of the conductive base material 14 a corresponding to the resin soaking restriction portion 15. At this time, as a method for applying the ink, a screen printing method, a coating method, a spray method, an ink jet method, or the like can be used.

Next, as shown in FIG. 3B, the applied ink is evacuated downward (in the direction of the arrow in FIG. 3B) through the holes 32 of the flat jig 31. Thereby, the water repellent material and the conductive carbon are dispersedly arranged in the region of the conductive base material 14 a corresponding to the resin soaking restriction portion 15.
Next, the water repellent carbon layer ink is applied to the upper surface of the conductive substrate 14a. At this time, as a method for applying the ink, a screen printing method, a coating method, a spray method, an ink jet method, or the like can be used.
Next, the conductive base material 14a coated with the water repellent carbon layer ink is baked. The firing temperature at this time is, for example, about 325 ° C., and the firing time is, for example, 1 hour.
Next, the portion outside the resin soaking restriction portion 15 is cut.
By performing each of the above steps, as shown in FIG. 2, the resin soaking restriction portion 15 can be formed adjacent to the outer edge portion of the gas diffusion layer 14.

4A and 4B show another example of the manufacturing method of the gas diffusion layer 14 and the resin soaking restriction portion 15 shown in FIG.
First, as shown in FIG. 4A, the sheet of the conductive base material 14a wound in a roll shape is pulled out toward a cylindrical jig 33 provided with a hole 34 at a position corresponding to the resin soaking restriction portion 15. . In this process, the water repellent carbon layer ink is applied to the upper surface of the conductive substrate 14a. As the ink application method, a screen printing method, a coating method, a spray method, an ink jet method, or the like can be used.

Next, the conductive base material 14 a drawn out onto the cylindrical jig 33 is evacuated from the inside of the cylindrical jig 33 through the holes 34. Thereby, as shown in FIG. 4B, the water repellent material and the conductive carbon are dispersedly arranged in the region of the conductive base material 14a corresponding to the resin soaking restriction portion 15.
Next, the water repellent carbon layer ink is applied again on the upper surface of the conductive substrate 14a. At this time, as a method for applying the ink, a screen printing method, a coating method, a spray method, an ink jet method, or the like can be used.
Next, the conductive base material 14a coated with the water repellent carbon layer ink is baked. The firing temperature at this time is, for example, about 325 ° C., and the firing time is, for example, 1 hour.
Next, the portion outside the resin soaking restriction portion 15 is cut.
By performing each of the above steps, as shown in FIG. 2, the resin soaking restriction portion 15 can be formed adjacent to the outer edge portion of the gas diffusion layer 14.

5A to 5D show still another example of the manufacturing method of the gas diffusion layer 14 and the resin soaking restriction portion 15 shown in FIG.
First, as shown in FIG. 5A, the lower surface of the conductive substrate 14 a is immersed in the water repellent carbon layer ink 36 disposed on the stage 35. As a result, as shown in FIG. 5B, the water repellent carbon layer ink 36 penetrates into the surface layer portion of the lower surface of the conductive substrate 14a to form the water repellent carbon layer 14b.

Next, as shown in FIG. 5C, only the region of the conductive base material 14a corresponding to the resin soaking restriction portion 15 is evacuated from the upper surface side of the conductive base material 14a. As a result, the water repellent carbon layer ink 36 is sucked upward (in the direction of the arrow in FIG. 5C), and as shown in FIG. 5D, the water repellent carbon layer region 36 corresponds to the resin infiltration restricting portion 15. Material and conductive carbon are dispersedly arranged. The evacuation is preferably performed while fixing the conductive base material 14a so as not to move from above the stage 35.
Next, the conductive substrate 14a shown in FIG. 5D is transferred to an incinerator (not shown) and baked. The firing temperature at this time is, for example, about 325 ° C., and the firing time is, for example, 1 hour.
By performing each of the above steps, as shown in FIG. 2, the resin soaking restriction portion 15 can be formed adjacent to the outer edge portion of the gas diffusion layer 14.

  The membrane / electrode assembly 1 shown in FIG. 1 is obtained by joining the gas diffusion layer 14 and the resin soaking restriction portion 15 obtained as described above to both surfaces of the polymer electrolyte membrane 11 by hot pressing or the like. be able to.

  In the first embodiment, since the resin soaking restriction part 15 is configured using the conductive base material 14a constituting the gas diffusion layer 14, the manufacturing efficiency of the resin soaking restriction part 15 (for example, the manufacturing cost) is increased. Reduction of manufacturing time and manufacturing time). Further, in the same manner as the water repellent carbon layer 14b, the resin soaking restriction portion 15 is configured by mixing the water repellent material and the conductive carbon with the conductive base material 14a. Further efficiency can be achieved.

  Next, the manufacturing method of the membrane electrode-frame assembly provided with the membrane electrode assembly 1 will be described with reference to FIGS. 6A to 6C.

First, as shown in FIG. 6A, the membrane electrode assembly 1 is placed in the molds 20 and 20.
Next, the resin material constituting the frame 16 is melted (softened) and poured in the direction of the arrow in FIG. 6A. At this time, since the molten resin material is restricted from moving to the gas diffusion layer 14 by the resin soaking restriction part 15, a part of the resin material is part of the resin soaking restriction part as shown in FIGS. 6B and 6C. A soaked portion 17 is formed in a part of 15.
Thereafter, the resin material is solidified. Thereby, the membrane electrode-frame assembly 2 shown in FIGS. 6B and 6C is completed.

  As the resin material constituting the frame body 16, for example, a thermoplastic resin material and a thermosetting resin material can be used. When a thermoplastic resin material is used, the resin may be melted at a high temperature and poured into the molds 20 and 20 and then placed in a low-temperature rectangular mold (not shown) and solidified. . Further, when a thermosetting resin material is used, the resin which has been heated (for example, around 50 ° C.) to have fluidity is poured into the molds 20, 20, and then the high temperature (eg, around 150 ° C.). What is necessary is just to make it harden | cure (solidify) in the rectangular-shaped metal mold | die (not shown) made into.

  Examples of the thermoplastic resin material include polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, Teflon, ABS resin, AS resin, and acrylic resin. Polyamide (PA) nylon, polyacetal (POM), polycarbonate (PC) modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene terephthalate glass resin ( PET-G), glass fiber reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP), polyphenylene sulfide (PPS), polysulfone (PSF) , Polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyetheretherketone (PEEK), thermoplastic polyimide (PI), polyamideimide (PAI) and the like.

  Examples of the thermosetting resin material include phenol resin (PF), epoxy resin (EP), melamine resin (MF), urea resin (urea resin, UF), unsaturated polyester resin (UP), alkyd resin, polyurethane (PUR). ) And thermosetting polyimide (PI).

  Next, the manufacturing method of the fuel cell (unit cell) 3 provided with the membrane electrode-frame assembly 2 will be described with reference to FIGS.

  First, as shown in FIG. 7, the gasket 18 is resin-molded on both surfaces of the membrane electrode-frame assembly 2 using the same resin material as that of the frame 16. At this time, the gasket 18 is formed adjacent to the frame 16 and the resin soaking restriction portion 15 (preferably soaking portion 17) so that the resin material constituting the gasket 18 does not soak into the gas diffusion layer 14. . The gasket 18 is for preventing leakage and mixing of fuel gas and oxidant gas supplied to the pair of gas diffusion layers 14 and 14 to the outside.

Next, as shown in FIG. 8, the membrane electrode-frame assembly 2 to which the gasket 18 is attached is sandwiched and fixed by a pair of separators 19 and 19. Thereby, the fuel cell 3 is completed.
One separator (anode separator) 19 is provided with a gas flow path 19 a for fuel gas at a position in contact with the gas diffusion layer 14. The other separator (cathode separator) is provided with a gas flow path 19a for oxidizing gas at a position in contact with the gas diffusion layer.

When a fuel gas is supplied to the gas flow path 19a of one separator 19 and an oxidant gas is supplied to the gas flow path 19a of the other separator 19, a current density of tens to hundreds of mA / cm ² is applied. 1, an electromotive force of about 0.7 to 0.8 V can be generated by one fuel cell (single cell).

  When the fuel cell 3 is used as a power source, the required number of fuel cells (unit cells) 3 shown in FIG. 8 can be connected in series and used as a so-called stack (not shown). In this case, in order to supply the reaction gas (fuel gas or oxidant gas) to the gas flow path 19a, the piping for supplying the reaction gas is branched into a number corresponding to the number of separators 19 to be used. A manifold that connects the tip to the gas flow path 19a is required. In the first embodiment, any known external manifold and internal manifold can be employed as the manifold.

  As described above, according to the membrane electrode assembly 1, the membrane electrode-frame assembly 2, and the fuel cell 3 according to the first embodiment of the present invention, the resin melted by heating adjacent to the outer edge portion of the gas diffusion layer 14. A resin soaking restriction portion 15 that can be restrained so that the material does not soak into the gas diffusion layer 14 is provided. Therefore, when the frame body is resin-molded adjacent to the outer edge portion of the membrane electrode assembly 1, excessive penetration of the resin material from the outer edge portion to the center portion of the gas diffusion layer 14 can be suppressed. Thereby, it can suppress that the gas diffusibility of the gas diffusion layer 14 is lost, and can suppress the fall of the power generation performance of a fuel cell compared with the past. Further, since the resin soaking restriction part 15 allows the resin material to soak into a part of the resin soaking restriction part 15, the resin soaking restriction part 15 and the frame body 16 can be firmly joined without a gap.

  In addition, the resin infiltration restricting portion 15 including the water repellent material and the conductive carbon with a larger weight per unit area than the water repellent carbon layer 14b can suppress the infiltration of the resin material into the gas diffusion layer 14. Although the clear mechanism has not been elucidated, it is presumed as follows.

  As the cause of excessive penetration of the resin material into the gas diffusion layer 14, the following two causes are mainly conceivable. One is that capillary action in the conductive base material 14a having a porous structure is promoted by a decrease in viscosity of the resin material melted by heating. The other is that when the frame is molded, the pressure applied to the resin material cannot be appropriately controlled due to a decrease in the viscosity of the resin material. As a result, the pressure becomes excessively high, and the conductive substrate 14a This facilitates the diffusion of the resin material at

  At the time of frame forming, the resin material is heated and liquefied at a temperature higher than its melting point. At this time, depending on the material of the resin material, the viscosity may be reduced to about several poises. Generally, the fluidity of the resin material increases as the viscosity decreases. For this reason, the resin material soaks into the conductive base material 14a excessively due to capillary action (progress of wetting to the base material), or the pressure applied to the resin material becomes excessively high, resulting in a wide area in the conductive base material 14a. The resin material may diffuse into the region.

In general, it is known that wetting (soaking) into a capillary tube into a member having a porous structure follows the following formula (for example, the Chemical Society of Japan, Colloid Science III-Application of biological colloids and colloids-No. 1 Edition 1996).
ΔP = 2γLcosθ / r

Here, ΔP indicates the pressure at which the liquid enters the capillary tube. When ΔP is positive, the liquid enters the capillary, and when ΔP is negative, the liquid is pushed out from the capillary. ΓL represents the surface tension of the liquid, r represents the radius of the capillary tube, θ represents the contact angle between the liquid and the capillary wall (in the first embodiment, the contact between the liquefied resin material and the conductive substrate 14a). Corner).
From the above equation, it can be seen that ΔP is negative and cos θ <0, θ> 90 ° is necessary to suppress the intrusion of the liquid into the capillary tube.

  It is considered that excessive penetration of the resin material into the conductive base material 14a (excessive progress of wetting) occurs because the surface energy of the conductive base material 14a is large and the contact angle is smaller than 90 °. On the other hand, when the porosity of the conductive base material 14a is large, the diffusion of the resin material in the conductive base material 14a is promoted unless the pressure applied to the resin material is appropriately controlled during frame forming. Resulting in.

  Therefore, in order to suppress excessive penetration of the resin material into the conductive base material 14a, it is effective to reduce the surface energy of the conductive base material 14a or to lower the porosity of the conductive base material 14a. It is believed that there is.

  In the first embodiment, since the resin soaking restriction portion 15 is configured by mixing the water repellent material and the conductive carbon with the conductive base material 14a, the porosity of the conductive base material 14a is reduced. Can do. Further, the water repellent material has an effect of reducing the surface energy of the conductive base material 14a. Therefore, the penetration of the resin material into the conductive base material 14a can be effectively suppressed.

  In the first embodiment, the resin soaking restriction portion 15 is configured by mixing the water repellent material and the conductive carbon with the conductive base material 14a. However, the present invention is not limited to this. For example, the resin soaking restriction unit 15 may be configured by mixing only conductive carbon into the conductive base material 14a. In this case, the porosity of the conductive base material 14a can be lowered according to the amount of mixed conductive carbon, and the penetration of the resin material into the conductive base material 14a can be suppressed.

  Moreover, you may comprise the resin penetration control part 15 by mixing only a water repellent material with the electroconductive base material 14a. In this case, according to the amount of the mixed water repellent material, the porosity of the conductive substrate 14a can be lowered, and the surface energy of the conductive substrate 14a can be lowered. Thereby, the penetration of the resin material into the conductive base material 14a can be further effectively suppressed.

  Further, the resin soaking restriction portion 15 may be configured by mixing a member different from the water repellent material and the conductive carbon into the conductive base material 14a. The member preferably does not chemically react with each member, does not elute due to the heat of the heated resin material, and is flexible so as not to damage the catalyst layer 13. An example of such a member is a fluorine rubber material.

  Further, the resin soaking restriction portion 15 may be constituted by a member different from each member constituting the gas diffusion layer 14.

<< Second Embodiment >>
A membrane / electrode assembly according to a second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a partially enlarged cross-sectional view of a membrane electrode-frame assembly including the membrane electrode assembly according to the second embodiment of the present invention. The membrane electrode assembly 1A of the second embodiment is different from the membrane electrode assembly 1 of the first embodiment in that one electrode layer 12 is shifted in a direction parallel to the polymer electrolyte membrane 11. And the point that the resin soaking restriction portion 15 is not provided adjacent to the gas diffusion layer 14 of the one electrode layer 12.

  When the membrane electrode assembly 1A is configured in this way, when the frame body 16 is resin-molded adjacent to the outer edge portion of the membrane electrode assembly 1A, the gas diffusion layer 14 not provided with the resin soaking restriction portion 15 is provided. The resin material constituting the frame body 16 may flow excessively. However, the electrochemical reaction in the fuel cell mainly occurs at a portion where the pair of gas diffusion layers 14 and 14 face each other. That is, even if the resin material soaked portion 17A occurs in a region where the pair of gas diffusion layers 14, 14 do not face each other, the power generation performance is not affected.

  Therefore, even if the membrane electrode assembly 1A is configured as in the second embodiment, when the frame body 16 is resin-molded, the penetration of the resin material into the gas diffusion layer 14 is suppressed, and the power generation performance is reduced. Can be suppressed.

<< Third Embodiment >>
A membrane electrode assembly according to a third embodiment of the present invention will be described with reference to FIGS. 10A to 10C and FIG. FIG. 10A to FIG. 10C are schematic views showing a method for producing a resin soaking restriction part of a membrane electrode assembly according to the third embodiment of the present invention. FIG. 11 is a partially enlarged cross-sectional view of a membrane electrode-frame assembly including a membrane electrode assembly according to the third embodiment of the present invention.

  The membrane electrode assembly 1B of the third embodiment is different from the membrane electrode assembly 1 of the first embodiment in that the weight per unit area of the water repellent material and the conductive carbon contained in the resin soaking restriction portion 15A is This is the point that the inner edge side region in the vicinity of the gas diffusion layer 14 is larger than the edge side region.

Specifically, the resin soaking restriction part 15A is produced as follows.
First, as shown in FIG. 10A, a convex jig 37 having two-step convex portions is pressed against the conductive base material 14a having a rectangular cross section to compress the outer edge portion of the conductive base material 14a. Thereby, as shown in FIG. 10B, the outer edge portion of the conductive base material 14 a is deformed according to the shape of the convex jig 37.

Next, as shown in FIG. 10C, the water repellent carbon layer ink is applied to the space formed by the deformation and the surface of the conductive substrate 14a. At this time, as a method for applying the ink, a screen printing method, a coating method, a spray method, an ink jet method, or the like can be used.
Next, the conductive base material 14a coated with the water repellent carbon layer ink is baked. The firing temperature at this time is, for example, about 325 ° C., and the firing time is, for example, 1 hour.
By performing each of the above steps, the resin weight is increased so that the weight per unit area of the water repellent material and the conductive carbon contained in the inner edge side region of the resin soaking restriction portion 15A is larger than that of the outer edge side region of the resin soaking restriction portion 15A. The soaking restriction part 15A can be produced.

  FIG. 11 shows the case where the frame 16 is resin-molded adjacent to the resin soaking restriction portion 15A produced as described above. That is, in the outer edge side region of the resin soaking restriction portion 15A where the weight of the water repellent material and the conductive carbon is small, the soaking portion 17 soaked with the resin material melted by heating is generated. On the other hand, in the inner edge side region of the resin soaking restriction portion 15A where the water repellent material and the conductive carbon are large in weight, soaking of the resin material melted by heating is suppressed. Thereby, permeation of the resin material into the gas diffusion layer 14 can be suppressed, and a decrease in power generation performance can be suppressed as compared with the conventional case. Further, since the resin material soaks into the outer peripheral side region of the resin soaking restriction portion 15, the resin soaking restriction portion 15 and the frame body 16 can be firmly joined without a gap.

  In addition, this invention is not limited to said each embodiment, It can implement in another various aspect. For example, in the third embodiment, the conductive base material 14a is deformed by using a convex jig having a two-step convex portion, so that it is included in the inner edge side region and the outer edge side region of the resin soaking restriction portion 15A. The weight per unit area of the water repellent material and the conductive carbon is changed, but the present invention is not limited to this. For example, the resin soaking restriction portion 15A may be produced by filling only the inner edge side region of the resin soaking restriction portion 15A with a water repellent material or conductive carbon. Further, the resin soaking restriction portion 15A may be configured so that the weight per unit area of the water repellent material or the conductive carbon gradually increases from the outer edge portion to the inner edge portion of the resin soaking restriction portion 15A.

  Moreover, in the said 1st Embodiment, as shown in FIG. 2, although the thickness of the resin penetration control part 15 was made the same as the thickness of the gas diffusion layer 14, this invention is not limited to this. As shown in FIG. 12, if the thickness of the resin soaking restriction portion 15B is set to be larger than the thickness of the water repellent carbon layer 14b, the soaking of the resin material into the gas diffusion layer 14 can be suppressed more than before. In addition, as shown in FIG. 12, if the thickness of the resin soaking restriction portion 15B is set to be equal to or less than the thickness of the gas diffusion layer 14, the thickness of a part of the conductive base material 14a is increased as in the conventional case. Therefore, it is easy to produce the conductive substrate 14a. The thickness of the resin soaking restriction portion 15 here is the height of the region where water repellent material or conductive carbon is mixed in order to restrict the soaking of the resin material into the gas diffusion layer 14 (in FIG. Direction).

  Further, it is preferable that the water repellent material or the conductive carbon contained in the resin soaking restriction portion 15 is dispersed substantially uniformly in a direction parallel to the thickness direction of the conductive base material 14a. Thereby, the penetration of the resin material into the gas diffusion layer 14 can be effectively regulated.

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

  The membrane electrode assembly, the membrane electrode-frame assembly, and the polymer electrolyte fuel cell according to the present invention are formed on the gas diffusion layer when the frame body is resin-molded adjacent to the outer edge of the membrane electrode assembly. Since the penetration of the resin material can be suppressed and the decrease in power generation performance can be suppressed, it is particularly useful for a moving body such as an automobile, a distributed power generation system, and a home cogeneration system.

It is a schematic cross section which shows the structure of the membrane electrode assembly concerning 1st Embodiment of this invention. FIG. 2 is a schematic cross-sectional view of a gas diffusion layer and a resin soaking restriction part included in the membrane electrode assembly shown in FIG. 1. It is a figure which shows an example of the manufacturing method of the gas diffusion layer and resin penetration control part which are shown in FIG. It is a figure which shows the process of following FIG. 3A. It is a figure which shows another example of the manufacturing method of the gas diffusion layer and resin penetration control part which are shown in FIG. It is a figure which shows the process of following FIG. 4A. It is a figure which shows another example of the manufacturing method of the gas diffusion layer and resin penetration control part which are shown in FIG. It is a figure which shows the process of following FIG. 5A. It is a figure which shows the process of following FIG. 5B. It is a figure which shows the process of following FIG. 5C. It is a figure which shows a mode that a frame is resin-molded adjacent to the outer edge part of the membrane electrode assembly shown in FIG. It is a partial expanded sectional view of the membrane electrode-frame assembly which resin-molded the frame body adjacent to the outer edge part of the membrane electrode assembly shown in FIG. FIG. 6B is a partially enlarged plan view of the membrane electrode-frame assembly shown in FIG. 6B. It is a partially expanded sectional view which shows the state which has arrange | positioned the gasket so that the membrane electrode-frame assembly shown to FIG. 6B may be pinched | interposed. It is sectional drawing of the polymer electrolyte fuel cell provided with the membrane electrode assembly concerning 1st Embodiment of this invention. It is a partially expanded sectional view which shows typically the membrane electrode assembly concerning 2nd Embodiment of this invention. It is a schematic diagram which shows the preparation methods of the resin penetration control part of the membrane electrode assembly concerning 3rd Embodiment of this invention. It is a figure which shows the process of following FIG. 10A. It is a figure which shows the process of following FIG. 10B. It is a partially expanded sectional view of the membrane electrode-frame assembly formed by resin-molding the frame body adjacent to the outer edge portion of the membrane electrode assembly according to the third embodiment of the present invention. It is a schematic cross section which shows the structure of the membrane electrode assembly concerning the modification of this invention. It is a schematic cross section which shows the structure of the conventional membrane electrode assembly. It is a partial expanded sectional view of the membrane electrode-frame assembly which resin-molded the frame body adjacent to the outer edge part of the conventional membrane electrode assembly. FIG. 14B is a partially enlarged plan view of the membrane electrode-frame assembly shown in FIG. 14A.

Explanation of symbols

1, 1A, 1B, 1C Membrane electrode assembly 2 Membrane electrode-frame assembly 3 Polymer electrolyte fuel cell 11 Polymer electrolyte membrane 12 Electrode layer 13 Catalyst layer 14 Gas diffusion layer 14a Conductive substrate 14b Water-repellent carbon layer 15, 15A, 15B Resin soaking restriction part 16 Frame 17 Soaking part 18 Gasket 19 Separator 19a Gas flow path 20 Mold 31 Flat jig 32, 34 Hole 33 Cylindrical jig 35 Stage 36 Water repellent carbon layer ink 37 Convex Part jig

Claims (9)

A polymer electrolyte membrane;
A pair of catalyst layers facing each other across the polymer electrolyte membrane;
A pair of gas diffusion layers facing each other across the polymer electrolyte membrane and the pair of catalyst layers;
The resin material disposed adjacent to the outer edge of at least one gas diffusion layer of the pair of gas diffusion layers and allowing the resin material melted by heating to permeate in part, while the resin material is the gas diffusion layer A resin soaking regulation part that can be regulated so as not to soak into
I have a,
The gas diffusion layer has a water repellent carbon layer containing a water repellent material and conductive carbon on the surface layer portion on the catalyst layer side of the conductive substrate having a porous structure,
The resin soaking restriction part is configured to include the water repellent material in the conductive base material with a weight per unit area larger than a unit weight of the water repellent material included in the gas diffusion layer. A membrane electrode assembly that regulates penetration into the gas diffusion layer .   2. The membrane / electrode assembly according to claim 1, wherein a thickness of the resin soaking restriction portion is larger than a thickness of the water-repellent carbon layer and equal to or less than a thickness of the gas diffusion layer. 3. The membrane / electrode assembly according to claim 1, wherein a weight per unit area of the water-repellent material of the resin soaking restriction portion is larger in an inner edge side region near the gas diffusion layer than in an outer edge side region. The water-repellent material of the resin penetration restricting portion, in the thickness direction parallel to the direction of the gas diffusion layer is distributed to one uniform, membrane electrode assembly according to any one of claims 1 to 3 body. The gas diffusion layer has a water repellent carbon layer containing a water repellent material and conductive carbon on the surface layer portion on the catalyst layer side of the conductive substrate having a porous structure,
The resin soaking restriction portion is configured to include the conductive carbon in the conductive base material with a weight per unit area larger than a unit weight of the conductive carbon included in the water-repellent carbon layer. The membrane electrode assembly according to any one of claims 1 to 4 , which regulates soaking into the gas diffusion layer. The membrane electrode assembly according to claim 5 , wherein a weight per unit area of the conductive carbon of the resin soaking restriction portion is larger in an inner edge side region near the gas diffusion layer than in an outer edge side region. The conductive carbon of the resin penetration restricting portion, in the thickness direction parallel to the direction of the gas diffusion layer is distributed to an equalizing membrane electrode assembly according to claim 5 or 6. The membrane electrode assembly according to any one of claims 1 to 7 ,
A frame formed of the resin material, disposed adjacent to the outer edge of the resin soaking restriction portion,
The membrane electrode-frame assembly, wherein the resin material of the frame body is infiltrated into the part of the resin soaking restriction portion. The membrane electrode-frame assembly according to claim 8 ,
A pair of separators arranged to face each other across the membrane electrode-frame assembly;
A polymer electrolyte fuel cell.

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