fuel cell

Abstract

To provide a fuel cell that can be constructed thinly while ensuring sufficient thickness of the gas diffusion layer. [Solution] A fuel cell cell that generates electricity by the reaction of a reaction gas comprises a membrane electrode assembly having an electrolyte membrane and a catalyst layer, a gas diffusion layer laminated on the membrane electrode assembly and made of a porous metal, and a separator laminated on the gas diffusion layer and parallel to the plane direction of the membrane electrode assembly, wherein the gas diffusion layer has grooves through which the reaction gas flows on the separator side.

Description

Technical Field

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[0001] The present disclosure relates to fuel cells.

Background Art

[0002] Various techniques related to the layer structure of fuel cells have been proposed. For example, Patent Document 1 discloses a technique of providing a plurality of grooves on the surface of a separator on the catalyst layer side. The plurality of grooves are used as flow paths for reaction gases. Also, in order to supply reaction gases to the catalyst layer more efficiently, it is known to use a gas diffusion layer composed of a porous body between the catalyst layer and the separator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a fuel cell using a separator with flow paths formed and a gas diffusion layer, when the gas diffusion layer is thinned for the purpose of reducing the size of the fuel cell, the cross-sectional area in the flow direction of the reaction gas flowing through the gas diffusion layer becomes smaller, and the pressure loss of the reaction gas increases. As a result, it becomes difficult for the reaction gas to spread over the entire surface of the catalyst layer, and there is a risk that the power generation efficiency will decrease. <​​​​​​​​​(1) According to one embodiment of the present disclosure, a fuel cell is provided that generates electricity by the reaction of a reaction gas. The fuel cell comprises a membrane electrode assembly having an electrolyte membrane and a catalyst layer, a gas diffusion layer laminated on the membrane electrode assembly and made of a porous metal, and a separator laminated on the gas diffusion layer, parallel to the plane direction of the membrane electrode assembly and in the shape of a flat plate, wherein the gas diffusion layer has grooves through which the reaction gas flows on the separator side. This type of fuel cell comprises a separator that is parallel to the plane direction of the membrane electrode assembly and is flat, and a gas diffusion layer having grooves through which the reaction gas flows on the separator side. Compared to a configuration in which grooves are provided in the separator, the overall thickness of the fuel cell can be reduced while ensuring the thickness of the gas diffusion layer. In other words, the fuel cell can be made thinner while suppressing pressure loss in the gas diffusion layer. (2) In the fuel cell cell of the above form, the groove may be formed in a rectangular shape in the cross-section of the gas diffusion layer cut in a direction perpendicular to the direction in which the reaction gas flows. In this type of fuel cell, the grooves are formed in a rectangular shape in the cross-section of the gas diffusion layer, which is cut perpendicular to the direction in which the reaction gas flows. Compared to configurations where the grooves are sinusoidal, this allows for a larger contact area between the gas diffusion layer and the separator while maintaining a sufficient groove cross-sectional area. As a result, even when pressure is applied in the thickness direction of the fuel cell, localized pressure on the gas diffusion layer can be suppressed, thereby preventing damage to the fuel cell and a decrease in power generation performance. (3) In the fuel cell cell of the above form, the gas diffusion layer may have a pore size distribution such that the pore size is smaller on the side farther from the membrane electrode assembly in the thickness direction compared to the side closer to the membrane electrode assembly. In this type of fuel cell, the gas diffusion layer has a pore size distribution such that the pore size is smaller on the side farther from the membrane electrode assembly compared to the side closer to the membrane electrode assembly in the thickness direction. This makes it easier to discharge water present in the gas diffusion layer, which is generally composed of a hydrophilic porous metal material, from the side closer to the membrane electrode assembly to the side further away. More specifically, in areas of the gas diffusion layer with relatively small pore sizes, the distance between metal particles is relatively close, resulting in a relatively strong water adsorption force. As a result, water can be attracted to the side of the gas diffusion layer farther from the membrane electrode assembly, improving the drainage performance of the gas diffusion layer. (4) In the fuel cell cell of the above form, the gas diffusion layer may have a through-channel that penetrates in the thickness direction and through which the reaction gas flows. In this type of fuel cell, the gas diffusion layer has through-channels that penetrate in the thickness direction, allowing the reaction gas to be supplied to the membrane electrode assembly via these channels. This ensures a pathway for the reaction gas even when water is present in the gas diffusion layer, thereby suppressing a decrease in the efficiency of the reaction gas supply. [Brief explanation of the drawing]

[0007] [Figure 1] This is a plan view of a fuel cell in one embodiment of the present disclosure. [Figure 2] This figure shows a cross-section cut along line II-II in Figure 1. [Figure 3] This is a cross-sectional view of a comparative example fuel cell. [Figure 4] This is a diagram illustrating a fuel cell according to a second embodiment. [Figure 5] This is a diagram illustrating a fuel cell according to a third embodiment. [Modes for carrying out the invention]

[0008] A. First Embodiment: A1. Configuration of fuel cell cell 100: Figure 1 is a plan view of a fuel cell cell 100 in one embodiment of the present disclosure. Figure 1 shows the fuel cell cell 100 as seen from the cathode-side separator 141, which will be described later. The fuel cell cell 100 has a rectangular external shape when viewed in the thickness direction. The fuel cell cell 100 generates electricity through the reaction of a reaction gas. In this embodiment, the reaction gas is hydrogen gas as a fuel gas and air as an oxidizing gas. The fuel cell cell 100 is used as a laminate of multiple cells stacked together, for example, as a power source for an electric vehicle.

[0009] The fuel cell cell 100 is formed with oxidizer gas manifolds 11a and 11b, refrigerant manifolds 12a and 12b, and fuel gas manifolds 13a and 13b. Oxidizer gas manifold 11a is used to supply oxidizer gas to the fuel cell cell 100. Oxidizer gas manifold 11b is used to discharge oxidizer gas from the fuel cell cell 100. Refrigerant manifold 12a is used to supply refrigerant to the fuel cell cell 100. Refrigerant manifold 12b is used to discharge refrigerant from the fuel cell cell 100. Fuel gas manifold 13a is used to supply fuel gas to the fuel cell cell 100. Fuel gas manifold 13b is used to discharge fuel gas from the fuel cell cell 100. The reaction gas flows from the supply manifolds 11a and 13a through groove GR to the discharge manifolds 11b and 13b.

[0010] Figure 2 shows a cross-section taken along the line II-II in Figure 1. The fuel cell cell 100 comprises a membrane electrode assembly 110, water-repellent layers 121 and 122, gas diffusion layers 131 and 132, a cathode-side separator 141, and an anode-side separator 142. In the following, the side with the cathode-side separator 141 may be referred to as the "cathode side," and the side with the anode-side separator 142 may be referred to as the "anode side."

[0011] <Configuration of the membrane electrode assembly 110> The membrane electrode assembly 110 has a flat, plate-like appearance when viewed in the thickness direction TD. The membrane electrode assembly 110 comprises an electrolyte membrane 111, a cathode-side catalyst layer 112, and an anode-side catalyst layer 113. The electrolyte membrane 111 transports protons generated on the anode side to the cathode side. The electrolyte membrane 111 is a solid polymer membrane, a proton-conducting ion-exchange membrane composed of a fluororesin such as perfluorocarbon sulfonic acid polymer. The cathode-side catalyst layer 112 is laminated on one side of the electrolyte membrane 111. The cathode-side catalyst layer 112 catalyzes the reduction reaction of the oxidizing gas. The anode-side catalyst layer 113 catalyzes the oxidation reaction of the fuel gas. The cathode-side catalyst layer 112 and the anode-side catalyst layer 113 are composed of carbon particles supporting a catalyst metal such as platinum. The anode-side catalyst layer 113 is laminated on the other side of the electrolyte membrane 111.

[0012] In this disclosure, "stacked" means not only a state in which components are in direct contact with each other and stacked on top of each other, but also a state in which other components are sandwiched between components. In this disclosure, the cathode-side catalyst layer 112 and the anode-side catalyst layer 113 are collectively referred to as the "catalyst layer."

[0013] <Composition of water-repellent layers 121 and 122> The water-repellent layers 121 and 122 have a flat, plate-like appearance when viewed in the thickness direction TD. Each of the water-repellent layers 121 and 122 is laminated on the side of the catalyst layers 112 and 113 opposite to the side in contact with the electrolyte membrane 111. The water-repellent layers 121 and 122 discharge water generated by the reduction reaction of the oxidizing gas to the gas diffusion layers 131 and 132. The water-repellent layers 121 and 122 also transfer electrons from the membrane electrode assembly 110 to the gas diffusion layers 131 and 132. The water-repellent layers 121 and 122 contain conductive carbon particles and a water-repellent agent. The water-repellent agent is, for example, a fluororesin such as polytetrafluoroethylene.

[0014] <Configuration of gas diffusion layers 131 and 132> The gas diffusion layers 131 and 132 are laminated on the side opposite to the surface of the water-repellent layers 121 and 122 that is in contact with the film electrode assembly 110. The gas diffusion layers 131 and 132 uniformly supply the reaction gas to the film electrode assembly 110, thereby promoting power generation. In addition, the gas diffusion layers 131 and 132 transfer electrons from the water-repellent layers 121 and 122 to the cathode-side separator 141 and the anode-side separator 142, respectively.

[0015] The gas diffusion layers 131 and 132 in this disclosure are composed of a porous metal. The porous metal is manufactured by foaming a metal such as aluminum, nickel, titanium, or stainless steel. Each of the gas diffusion layers 131 and 132 in this disclosure has a plurality of grooves GR formed on the surface that contacts the cathode-side separator 141 and the anode-side separator 142, respectively. The grooves GR are formed by, for example, cutting or laser processing. The reaction gas flows through the grooves GR. More specifically, the oxidizer gas flows through the space defined by the grooves GR and the cathode-side separator 141. The fuel gas flows through the space defined by the grooves GR and the anode-side separator 142. As shown in Figure 1, each groove GR is provided parallel to each other along the longitudinal direction of the fuel cell cell 100. Therefore, Figure 2 can be said to show a cross-section cut perpendicular to the direction in which the reaction gas flows.

[0016] As shown in FIG. 2, each groove GR in the present embodiment is formed in a rectangular shape in the cross-section of the gas diffusion layers 131 and 132 cut in a direction perpendicular to the direction in which the reaction gas flows. In other words, the gas diffusion layer 131 has a structure in which the convex portions 135 and the concave portions 136 are alternately continuous. The convex portion 135 protrudes toward the cathode-side separator 141 or the anode-side separator 142 and is in contact with the cathode-side separator 141 or the anode-side separator 142. The surface of the convex portion 135 that contacts the cathode-side separator 141 or the anode-side separator 142 is parallel to the cathode-side separator 141 and the anode-side separator 142. It can be said that the convex portion 135 constitutes the side surface of each groove GR. The concave portion 136 is recessed toward the membrane electrode assembly 110 side. It can be said that the concave portion 136 constitutes the bottom surface of each groove GR. The width of the convex portion 135 is, for example, 0.2 mm to 0.8 mm. The width of the concave portion 136 is, for example, 0.2 mm to 0.8 mm. The height of the convex portion 135 is, for example, 0.2 mm to 0.8 mm.

[0017] <Configuration of the Cathode-Side Separator 141 and the Anode-Side Separator 142> Hereinafter, when the cathode-side separator 141 and the anode-side separator 142 are not distinguished, the cathode-side separator 141 and the anode-side separator 142 are collectively referred to as a "separator". The separators 141 and 142 have a flat plate-like external shape. The separators 141 and 142 are parallel to the plane direction of the membrane electrode assembly 110. Each of the separators 141 and 142 is laminated on the surface opposite to the surface that contacts the water-repellent layers 121 and 122 in the gas diffusion layers 131 and 132, respectively. Electrons are transmitted from the gas diffusion layers 131 and 132 to the separators 141 and 142. The separators 141 and 142 are in contact with the convex portions 135 on the surfaces on the gas diffusion layer 131 and 132 sides. That is, the load applied to the separators 141 and 142 is also applied to the convex portions 135.

[0018] A2. Comparison with the fuel cell 500 of the comparative example: Figure 3 is a cross-sectional view of the comparative example fuel cell cell 500. Similar to Figure 2, Figure 3 shows a cross-section of the fuel cell cell 500 cut perpendicular to the direction in which the reaction gas flows. Also, only the cathode side configuration is shown in Figure 3, and the anode side configuration is omitted. The anode side configuration in the comparative example is the same as the cathode side configuration. In the comparative example fuel cell cell 500, the configuration of the gas diffusion layer 531 and the separator 541 differs from the configuration of the embodiment described above. The other configurations are the same as those of the fuel cell cell 100 in the embodiment, so the same reference numerals are used and their explanation is omitted.

[0019] The gas diffusion layer 531 has a flat, plate-like appearance when viewed in the thickness direction TD. The surface of the gas diffusion layer 531 is flat. That is, unlike the gas diffusion layers 131 and 132 of the embodiment, the gas diffusion layer 531 does not have grooves.

[0020] The separator 541 is manufactured by folding and bending a flat plate multiple times. The separator 541 has multiple grooves 500GR. The reaction gas flows through the grooves 500GR. More specifically, the reaction gas flows through the space defined by the grooves 500GR and the gas diffusion layer 531.

[0021] In the comparative example, since the groove 500GR is provided in the separator 541, it is difficult to construct a thin fuel cell while ensuring sufficient depth of the groove 500GR and thickness of the gas diffusion layer 531. Furthermore, the distance from the groove 500GR to the membrane electrode assembly 110 is relatively long. As a result, the reaction gas may not be sufficiently supplied to the membrane electrode assembly 110, potentially reducing the power generation efficiency of the fuel cell cell 500.

[0022] In contrast, the fuel cell cell 100 of the embodiment shown in Figure 2 has grooves GR through which the reaction gas flows provided in the gas diffusion layers 131 and 132. Therefore, compared to the configuration of the comparative example in which grooves 500GR are provided in the separator 541, the fuel cell cell 100 can be made thinner while ensuring the depth of the grooves GR and the thickness of the gas diffusion layers 131 and 132. Furthermore, the path for the reaction gas to reach the membrane electrode assembly 110 can be shortened. This improves the power generation efficiency of the fuel cell cell 100.

[0023] As described above, the fuel cell cell 100 of the first embodiment includes separators 141 and 142 parallel to the plane direction of the membrane electrode assembly 110, and a gas diffusion layer 131 having grooves GR through which the reaction gas flows on the surface on the separator 141 and 142 side. Compared to a configuration in which grooves 500GR are provided on the separator 541, the overall thickness of the fuel cell cell 100 can be reduced while ensuring the thickness of the gas diffusion layers 131 and 132. In other words, the fuel cell cell 100 can be made thinner while suppressing pressure loss in the gas diffusion layers 131 and 132. In addition, the distance between the grooves GR and the catalyst layers 112 and 113 can be shortened, improving the efficiency of reaction gas supply.

[0024] Furthermore, according to the fuel cell cell 100 of the first embodiment, since grooves GR are provided in the gas diffusion layers 131 and 132, compared to a configuration in which grooves 500GR are provided in the separator 541, it is possible to configure the spacing between grooves GR to be relatively narrow while ensuring the contact area between the separators 141 and 142 and the gas diffusion layers 131 and 132. Specifically, when grooves 500GR are provided in the separator 541, the grooves 500GR are formed by press working or the like. In this case, if the spacing between adjacent grooves 500GR is narrowed, the separator 541 between adjacent grooves 500GR becomes sharply pointed, and the contact area between the separator 541 and the gas diffusion layer 531 becomes smaller. As a result, localized pressure is applied to the gas diffusion layer 531, which may reduce power generation performance and durability.

[0025] In contrast, when grooves GR are provided in the gas diffusion layers 131 and 132, as in the fuel cell cell 100 of the first embodiment, the grooves GR are formed by cutting or laser processing of the porous metal body. That is, the grooves GR can be formed with a narrow spacing while keeping the protrusions 135 flat. This makes it possible to form the grooves GR with a narrow spacing while maintaining the contact area between the separator 541 and the gas diffusion layer 531.

[0026] Furthermore, in the fuel cell cell 100 of the first embodiment, since the gas diffusion layers 131 and 132 are made of a porous metal, the rigidity of the gas diffusion layers 131 and 132 can be increased compared to a configuration in which a porous material made only of non-metallic materials such as carbon is used as the gas diffusion layer. As a result, even if a relatively strong pressure in the thickness direction TD is applied to the gas diffusion layers 131 and 132, damage to the gas diffusion layers 131 and 132 can be suppressed. In addition, since metal materials generally have lower electrical resistance than carbon, conductivity can be improved compared to a configuration in which the gas diffusion layers 131 and 132 are made of carbon.

[0027] Furthermore, according to the fuel cell cell 100 of the first embodiment, the groove GR is formed in a rectangular shape in the cross-section of the gas diffusion layers 131, 132 cut in a direction perpendicular to the direction in which the reaction gas flows. Compared to configurations where the groove is sinusoidal, the contact area with the separators 141, 142 can be increased while ensuring the cross-sectional area of ​​the groove GR. As a result, even if pressure is applied in the thickness direction TD of the fuel cell cell 100, localized pressure on the gas diffusion layers 131, 132 can be suppressed, thereby preventing damage to the fuel cell cell 100 and a decrease in power generation performance.

[0028] B. Second Embodiment: Figure 4 is a diagram illustrating the fuel cell cell 100b of the second embodiment. Similar to Figure 2, Figure 4 shows a cross-section of the fuel cell cell 100b cut perpendicular to the direction in which the reaction gas flows. Note that in Figure 4, the anode side is omitted, and only the cathode side is shown. The fuel cell cell 100b of the second embodiment differs from the fuel cell cell 100 of the first embodiment in the configuration of the gas diffusion layer 131b. The other configurations are the same as those of the fuel cell cell 100 of the first embodiment, so their explanation is omitted.

[0029] The right side of Figure 4 schematically shows the pore size distribution of the gas diffusion layer 131b. In this embodiment, the gas diffusion layer 131b has a pore size distribution such that, in the thickness direction TD, the pore size is smaller on the side farther from the film electrode assembly 110 compared to the side closer to it. Such a gas diffusion layer 131b is formed by sequentially stacking, for example, a first layer made of metal powder having relatively large pores, a second layer made of metal powder having smaller pores than the first layer, and a third layer made of metal powder having smaller pores than the second layer. The gas diffusion layer 131b is not limited to the above method and may be manufactured by any method. The pore size distribution can be determined, for example, by the mercury intrusion method.

[0030] Furthermore, the gas diffusion layer 132 on the anode side may also have the above configuration, not just the cathode-side gas diffusion layer 131b. Alternatively, only the anode-side gas diffusion layer 132 may have the above configuration.

[0031] According to the fuel cell cell 100b of the second embodiment described above, the gas diffusion layer 131b has a pore size distribution such that the pore size is smaller on the side farther from the membrane electrode assembly 110 in the thickness direction TD compared to the side closer to the membrane electrode assembly 110. Therefore, water present in the gas diffusion layer 131b, which is generally composed of a hydrophilic porous metal, can be easily discharged from the side closer to the membrane electrode assembly 110 to the side farther away. More specifically, in the parts of the gas diffusion layer 131b with relatively small pore sizes, the distance between metal particles is relatively close, so the force that adsorbs water is relatively strong. As a result, water can be attracted to the side of the gas diffusion layer 131b farther from the membrane electrode assembly 110, and the drainage performance of the gas diffusion layer 131b can be improved.

[0032] C. Third Embodiment: Figure 5 is a diagram illustrating the fuel cell cell 100c of the third embodiment. Similar to Figure 2, Figure 5 shows a cross-section of the fuel cell cell 100c cut perpendicular to the direction in which the reaction gas flows. Note that in Figure 5, the anode side is omitted, and only the cathode side is shown. The fuel cell cell 100c of the third embodiment differs from the fuel cell cell 100 of the first embodiment in the configuration of the gas diffusion layer 131c. The other configurations are the same as those of the fuel cell cell 100 of the first embodiment, so their explanation is omitted. Note that in Figure 4, the anode side is omitted, and only the cathode side is shown.

[0033] As shown in Figure 5, the gas diffusion layer 131c has through-channels FP that penetrate in the thickness direction TD and through which the reaction gas flows. In this embodiment, the through-channels FP are provided in both the convex portion 135 and the concave portion 136. The through-channels FP are through holes provided in the thickness direction TD of the gas diffusion layer 131c. The reaction gas is supplied to the membrane electrode assembly 110 side through the through-channels FP.

[0034] Furthermore, the gas diffusion layer 132 on the anode side may also have the above configuration, not just the cathode-side gas diffusion layer 131c. Alternatively, only the anode-side gas diffusion layer 132 may have the above configuration. In addition, the fuel cell cell 100c of the third embodiment may be used in combination with the fuel cell cell 100b of the second embodiment.

[0035] According to the fuel cell cell 100c of the third embodiment described above, the gas diffusion layer 131c has a through-channel FP that penetrates in the thickness direction TD and through which the reaction gas flows, so that the reaction gas can be supplied to the membrane electrode assembly 110 side via the through-channel FP. As a result, even if water is present in the gas diffusion layer 131c, a path for the reaction gas can be secured and a decrease in the efficiency of reaction gas supply can be suppressed.

[0036] D. Other embodiments: (D1) In the above embodiment, the plurality of grooves GR were formed in a rectangular shape in the cross-section of the gas diffusion layers 131, 132 cut in a direction perpendicular to the direction in which the reaction gas flows, but the disclosure is not limited thereto. The plurality of grooves GR may be of any shape. Even in such a configuration, since grooves GR are provided in the gas diffusion layers 131, 132, the overall thickness of the fuel cell cell 100 can be reduced while maintaining the thickness of the gas diffusion layers 131, 132, compared to a configuration in which grooves are provided in the separators 141, 142.

[0037] (D2) In each of the above embodiments, the water-repellent layers 121 and 122 in the fuel cell cells 100, 100b and 100c may be omitted.

[0038] (D3) In each of the above embodiments, as shown in Figure 1, each of the plurality of grooves GR was provided parallel to each other along the longitudinal direction of the fuel cell cell 100, but the disclosure is not limited thereto. Each of the plurality of grooves GR may be provided in any shape when viewed in the thickness direction TD of the fuel cell cell 100. For example, each of the plurality of grooves GR may be provided in a meandering manner. Alternatively, there may be a configuration having only one groove GR instead of multiple grooves GR. In such a configuration, the single groove GR may form a so-called serpentine flow path that meanders back and forth between the manifolds 11a, 13a on the reaction gas supply side and the manifolds 11b, 13b on the reaction gas discharge side.

[0039] (D4) In each of the above embodiments, the portion of the separator 141, 142 that contacts the protrusion 135 may be made thicker than the other portions. With such a configuration, when a load in the thickness direction TD is applied to the fuel cell cells 100, 100b, 100c, the rigidity of the portion of the separator 141, 142 that is subjected to the localized load can be increased.

[0040] (D5) In each of the above embodiments, the fuel cell cells 100, 100b, and 100c may be used as water electrolysis cells.

[0041] (D6) In the first embodiment described above, grooves GR were provided in both the cathode-side gas diffusion layer 131 and the anode-side gas diffusion layer 132, but the disclosure is not limited thereto. Grooves GR may be provided in only one of the gas diffusion layers 131 and 132.

[0042] (D7) In the second embodiment described above, the porosity of the gas diffusion layer 131b may be smaller on the side farther from the film electrode assembly 110 in the thickness direction TD compared with the side closer to the film electrode assembly 110. The porosity can be measured by, for example, the Archimedes method or the mercury porosity method.

[0043] (D8) In the third embodiment described above, the through-flow channel FP was provided in both the convex portion 135 and the concave portion 136, but the disclosure is not limited thereto. The through-flow channel FP may be provided in only one of the convex portion 135 and the concave portion 136.

[0044] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0045] 11a, 11b… Oxidizer gas manifold, 12a, 12b… Refrigerant manifold, 13a, 13b… Fuel gas manifold, 100, 100b, 100c, 500… Fuel cell cell, 110… Membrane electrode assembly, 111… Electrolyte membrane, 112… Cathode-side catalyst layer, 113… Anode-side catalyst layer, 121, 122… Water-repellent layer, 131, 131b, 131c, 132… Gas diffusion layer, 135… Convex portion, 136… Recess, 141… Cathode-side separator, 142… Anode-side separator, 500GR, GR… Groove, 531… Gas diffusion layer, 541… Separator, FP… Through-channel, TD… Thickness direction

Claims

1. A fuel cell that generates electricity through the reaction of a reaction gas, A membrane electrode assembly having an electrolyte membrane and a catalyst layer, A gas diffusion layer, laminated onto the aforementioned membrane electrode assembly and composed of a porous metal body, A separator, which is laminated on the gas diffusion layer, is parallel to the plane direction of the film electrode assembly, and is in the shape of a flat plate, Equipped with, The gas diffusion layer has grooves through which the reaction gas flows on the separator-side surface. Fuel cell.

2. A fuel cell cell according to claim 1, The groove is formed in a rectangular shape in the cross-section of the gas diffusion layer, which is cut in a direction perpendicular to the direction in which the reaction gas flows. Fuel cell.

3. A fuel cell cell according to claim 1, The gas diffusion layer has a pore size distribution such that, in the thickness direction, the pore size is smaller on the side farther from the film electrode assembly compared to the side closer to the film electrode assembly. Fuel cell.

4. A fuel cell cell according to any one of claims 1 to 3, The gas diffusion layer has through-channels that penetrate in the thickness direction and through which the reaction gas flows. Fuel cell.

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