JP2007073192A - Fuel cell and fuel cell system equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell capable of suppressing generation and detention of liquid water in a reaction gas flow channel, and downsizing in a lamination direction of a power generation cell. <P>SOLUTION: The fuel cell is provided with a first separator 11 with at least a part of its cross section corrugated with a recess part of one face forming an oxidant gas flow channel and another recess part of another face forming a cooling medium flow channel. The oxidant gas flow channel and the cooling medium flow channel have a serpentine shape folded toward the same direction by folding parts, and are connected to a manifold through a manifold communication part at both an inlet side and an outlet side. The manifold communication part and the folded parts consist of a plurality of protruded parts formed in a lattice-point shape, the manifold at the inlet side of the cooling medium flow channel communicating part is adjacent to the manifold and the manifold communicating part of the inlet side of the oxidant gas flow channel, and the oxidant gas flowing in the oxidant gas flow channel and the cooling medium flowing in the cooling medium flow channel flow in the same direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell and a fuel cell system including the same.

  A fuel cell is a device that generally obtains electric energy using hydrogen and oxygen as fuel. This fuel cell is environmentally superior and can realize high energy efficiency, and therefore has been widely developed as a future energy supply system.

  In this fuel cell, a separator having a fluid passage for supplying a fuel gas containing hydrogen and a fluid passage for supplying an oxidant gas containing oxygen are formed on both sides of an electrolyte membrane made of a solid polymer or the like. And a power generation cell provided with a separator. A predetermined number of the power generation cells are stacked to constitute a fuel cell stack. There is a demand for downsizing the fuel cell stack.

  Therefore, a technique is disclosed that uses a metal plate that has been pressed in a concavo-convex shape as the separator (see, for example, Patent Document 1). According to this technique, since the recesses on the front and back surfaces of the separator are used as the reaction gas channel and the cooling water channel, the fuel cell can be reduced in size. In addition, since the reaction gas channel has a serpentine shape, the reaction gas is efficiently supplied to the electrolyte.

  However, when the technique of Patent Document 1 is used, the reaction gas flow path flows through the serpentine flow path, and the cooling water flow path flows through the straight flow path. In this case, liquid water may stay in the reaction gas passage on the cathode side due to the temperature distribution of the reaction gas passage and the cooling water passage caused by the flow of the cooling water. In particular, it is difficult to remove liquid water staying in the folded portion of the serpentine channel. As a result, the reaction gas flow rate may vary between the power generation cells.

  Therefore, a technique for defining the shapes of the serpentine type oxidant gas flow path and the cooling medium flow path using a carbon separator is disclosed (for example, see Patent Document 2). According to this technique, it is possible to define the channel shape on the other surface without being restricted by the channel shape formed on one surface of the separator.

JP 2005-108505 A Japanese National Patent Publication No. 9-511356

  However, the thickness of the carbon separator becomes larger than the thickness of the metal plate that has been pressed into a concavo-convex shape. As a result, in the technique of Patent Document 2, the fuel cell becomes large in the stacking direction of the power generation cells.

  The present invention provides a fuel cell that can suppress the generation and retention of liquid water in a serpentine-shaped reaction gas flow path, and that can be miniaturized in the stacking direction of power generation cells, and a fuel cell system including the fuel cell. The purpose is to do.

  In the fuel cell according to the present invention, a first portion in which at least a part of a cross section is corrugated, a concave portion on one surface forms an oxidant gas flow channel, and a concave portion adjacent to the concave portion on one surface on the other surface forms a cooling medium flow channel. The oxidant gas flow path and the cooling medium flow path have a serpentine shape that is folded back in the same direction by the turn-back portion, and are connected to the manifold via the manifold communication portion on both the inlet side and the outlet side. The communication part and the folded part are composed of a plurality of protrusions formed in a lattice point, and the manifold on the inlet side of the coolant flow path is adjacent to the manifold on the inlet side of the oxidant gas flow path and the manifold communication part. The oxidizing gas flowing in the agent gas flow path and the cooling medium flowing in the cooling medium flow path flow in the same direction.

  In the fuel cell according to the present invention, the oxidant gas flow path is cooled by the cooling medium. In this case, the temperature in the vicinity of the inlet of the oxidant gas flow path is the lowest. Thereby, drying of the cathode and electrolyte of the fuel cell by the oxidant gas is suppressed. Further, the temperature of the cooling medium is rising at the folded portion of the oxidant gas flow path. Thereby, liquefaction of water generated by the power generation reaction is suppressed at the folded portion of the oxidant gas flow path. Therefore, in the fuel cell according to the present invention, the stagnation of the liquid water at the oxidant gas folding portion is suppressed. As a result, the variation in the reaction gas flow rate in the fuel cell according to the present invention is suppressed.

  Further, since the recesses formed on both surfaces of the first separator are used as the cooling medium flow path and the oxidant gas flow path, the fuel cell according to the present invention is miniaturized in the stacking direction. Since the manifold communication portion and the turn-up portion are composed of a plurality of protrusions formed in a lattice point, the shape of the oxidant gas flow path and the cooling medium flow path is the same as the manifold communication portion and the turn-back on the back side. It is not restrained by the part.

  A fuel gas channel is formed on the other surface, and a second separator facing the first separator is sandwiched between a power generation unit including an electrolyte membrane. The fuel gas channel has a serpentine shape that is folded back by a folded portion and is on the inlet side And the manifold on the outlet side of the fuel gas passage are connected to the manifold, the manifold on the inlet side of the fuel gas passage is adjacent to the manifold on the outlet side of the coolant passage or the oxidant gas passage, and the fuel gas passage The flow direction of the fuel gas in the straight portion may be opposite to the flow direction in the straight portion of the oxidant gas. In this case, the fuel gas concentration distribution and the oxidant gas concentration distribution do not overlap. Therefore, the dispersion | variation in the electric power generation distribution in an electric power generation part is suppressed. As a result, the power generation efficiency of the fuel cell according to the present invention is improved. The electrolyte membrane may be composed of a solid polymer having hydrogen ion conductivity.

  A fuel cell system according to the present invention includes a fuel cell according to claim 2, a cooling medium supply means for supplying a cooling medium to a manifold on the inlet side of the cooling medium flow path, and an inlet side of the oxidizing gas flow path. An oxidant gas supply means for supplying an oxidant gas to the manifold, and a fuel gas supply means for supplying the fuel gas to the manifold on the inlet side of the fuel gas flow path are provided.

  In the fuel cell system according to the present invention, the cooling medium is supplied to the manifold on the inlet side of the cooling medium flow path by the cooling medium supply means, and the oxidant gas is supplied to the inlet side of the oxidant gas flow path by the oxidant gas supply means. An oxidant gas is supplied to the manifold. In this case, the oxidant gas flowing in the oxidant gas flow path and the cooling medium flowing in the cooling medium flow path flow in the same direction.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to suppress generation | occurrence | production and retention of liquid water in the folding | turning part of a serpentine-shaped oxidant gas flow path, a fuel cell can be reduced in the lamination direction of an electric power generation cell.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 is a schematic diagram showing an overall configuration of a fuel cell system 100 according to the first embodiment. As shown in FIG. 1, the fuel cell system 100 includes a fuel cell 200, a cooling water circulation pump 201, an oxidant gas supply unit 202, and a fuel gas supply unit 203. In this embodiment, a polymer electrolyte fuel cell is used as the fuel cell 200.

  The cooling water circulation pump 201 is a pump for supplying cooling water to the cooling water flow path of the fuel cell 200. The cooling water circulation pump 201 may supply other cooling medium such as ethylene glycol and oil to the fuel cell 200 instead of the cooling water. The oxidant gas supply means 202 is a device that supplies an oxidant gas containing oxygen to the cathode of the fuel cell 200. As the oxidant gas supply unit 202, for example, an air pump can be used. The fuel gas supply means 203 is a device that supplies a fuel gas containing hydrogen to the anode of the fuel cell 200. As the fuel gas supply means 203, a reformer, a hydrogen cylinder, a liquid hydrogen tank, or the like can be used.

  Hereinafter, the details of the fuel cell 200 will be described with reference to FIGS. FIG. 2 is an exploded perspective view of the fuel cell 200 according to the present embodiment. As shown in FIG. 2, the fuel cell 200 includes a power generation cell having a structure in which a power generation unit 12 configured of a membrane electrode assembly (MEA) is sandwiched between a separator 11 and a separator 13.

  Although simplified in FIG. 2, in the actual fuel cell 200, a plurality of the power generation cells are stacked. The separators 11 and 13 are made of a metal such as stainless steel subjected to press working. Here, the stacking direction of the power generation cells is the Z direction, the direction parallel to one side of the power generation cell and perpendicular to the Z direction is the X direction, and the direction perpendicular to the direction X and the direction Z is the direction Y.

  A cooling water inlet manifold 21a, an oxidant gas inlet manifold 22a, and a fuel gas outlet manifold 23b are sequentially formed in the Y direction at one end of the separators 11 and 13 and the power generation unit 12 in the X direction. A fuel gas inlet manifold 23a, an oxidant gas outlet manifold 22b, and a cooling water outlet manifold 21b are sequentially formed in the Y direction at the other ends in the X direction of the separators 11 and 13 and the power generation unit 12.

  Cooling water is supplied to the cooling water inlet manifold 21a from the cooling water circulation pump 201 of FIG. The oxidant gas inlet manifold 22a is supplied with oxidant gas from the oxidant gas supply means 202 of FIG. Fuel gas is supplied to the fuel gas inlet manifold 23a from the fuel gas supply means 203 of FIG.

  FIG. 3 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 3, the power generation unit 12 includes an electrolyte membrane 31 made of a solid polymer such as perfluorosulfonic acid. The power generation unit 12 includes a cathode 32 between the electrolyte membrane 31 and the separator 11, and an anode 33 between the electrolyte membrane 31 and the separator 13. The cathode 32 and the anode 33 include a catalyst layer made of platinum-supporting carbon on the electrolyte membrane 31 side, and a gas diffusion layer made of carbon or the like on the opposite side of the electrolyte membrane 31.

  For example, the separators 11 and 13 are pressed into a concavo-convex shape so as to have a wave shape. Thereby, a plurality of groove portions are formed on both surfaces of the separators 11 and 13. These grooves are used as a cooling water channel, an oxidant gas channel, and a fuel gas channel. Details will be described below.

  A groove portion 42 of the separator 11 that forms a space between the separator 11 and the power generation unit 12 is used as an oxidant gas flow path 52 described later. A groove 43 of the separator 13 that forms a space between the separator 13 and the power generation unit 12 is used as a fuel gas channel 53 described later. A groove portion 41 of the separator 11 and a groove portion 44 of the separator 13 that form a space between the separator 11 and the separator 13 are used as a cooling water channel 51 described later. Thus, since the groove parts formed on both surfaces of the separators 11 and 13 are used as the reaction gas flow path and the cooling water flow path, the fuel cell 200 is downsized in the stacking direction.

  FIG. 4 is a plan view showing a surface of the separator 11 on the side opposite to the power generation unit 12. As shown in FIG. 4, a cooling water flow path 51 is formed on the surface of the separator 11 opposite to the power generation unit 12 so as to meander once and half in the X direction. The straight portion of the cooling water channel 51 includes a plurality of grooves 41 formed in a stripe shape in the X direction.

  Further, on the surface of the separator 11 opposite to the power generation unit 12, between the cooling water inlet manifold 21 a and the plurality of grooves 41, between the cooling water outlet manifold 21 b and the plurality of grooves 41, and the cooling water channel 51. A dimple portion 54 is formed at the folded portion. The plurality of grooves 41 are connected to the cooling water inlet manifold 21a and the cooling water outlet manifold 21b through the dimples 54. In the dimple portion 54, a plurality of protrusions 55 are formed in a lattice point shape. The plurality of protrusions 55 can be formed by embossing or the like, for example. The forward path and the return path of the cooling water flow path 51 are partitioned by a partition portion. This partition part can be formed by press molding or the like.

  FIG. 5 is a plan view showing a surface of the separator 11 on the power generation unit 12 side. Therefore, FIG. 5 shows the back surface of the separator 11 shown in FIG. As shown in FIG. 5, an oxidant gas flow path 52 is formed on the surface of the separator 11 on the power generation unit 12 side so as to meander once and half in the X direction. The straight portion of the oxidant gas flow path 52 includes a plurality of groove portions 42 formed in a stripe shape in the X direction. As described with reference to FIG. 3, the groove portion 42 and the groove portion 41 of FIG.

  Further, on the surface of the separator 11 on the power generation unit 12 side, between the oxidant gas inlet manifold 22a and the plurality of grooves 42, between the oxidant gas outlet manifold 22b and the plurality of grooves 42, and the oxidant gas flow path. A dimple portion 56 is formed at the folded portion 52. The plurality of groove portions 42 are connected to the oxidant gas inlet manifold 22 a and the oxidant gas outlet manifold 22 b through the dimple portions 56. The dimple portion 56 is formed integrally with the dimple portion 54 of FIG. In the dimple portion 56, projections 57 are formed between the projections 55 in the dimple portion 54.

  From the above, the oxidant gas flow path 52 and the cooling water flow path 51 have a front and back integrated structure in the separator 11. That is, the cooling water channel 51 is formed on the back surface of the position of the oxidant gas channel 52. Since the cooling water inlet manifold 21a is adjacent to the oxidant gas inlet manifold 22a and the dimple portion 54 connected to the cooling water inlet manifold 21a of the oxidant gas flow path 52, the oxidant gas and the cooling water are separated from the separator 11. Flow in the same direction on each face. That is, when the separator 11 is viewed from one of the surfaces, the flow direction of the oxidant gas matches the flow direction of the cooling water.

  In this embodiment, a dimple portion 56 is formed between the oxidant gas inlet manifold 22a and the groove portion 43, and a dimple portion 54 is formed at a position corresponding to the separator 11 on the surface on the cooling water channel 51 side. . Therefore, the flow path between the oxidant gas inlet manifold 22 a and the groove 43 is not restricted by the shape of the cooling water flow path 51.

  FIG. 6 is a plan view showing a surface of the separator 13 on the power generation unit 12 side. As shown in FIG. 6, a fuel gas flow path 53 is formed on the surface of the separator 13 on the power generation unit 12 side so as to meander once and half in the X direction. The straight portion of the fuel gas channel 53 includes a plurality of grooves 43 formed in a stripe shape in the X direction.

  Further, on the surface of the separator 13 on the power generation unit 12 side, the fuel gas inlet manifold 23 a and the plurality of grooves 43, the fuel gas outlet manifold 23 b and the plurality of grooves 43, and the fuel gas flow path 53 are folded back. A dimple portion 58 is formed in the portion. The plurality of grooves 43 are connected to the fuel gas inlet manifold 23a and the fuel gas outlet manifold 23b through the dimples 58. In the dimple portion 58, a plurality of protrusions 59 are formed in a lattice point shape. The plurality of protrusions 59 can be formed by embossing or the like, for example. The forward path and the return path of the fuel gas channel 53 are partitioned by a partitioning portion. This partition part can be formed by press molding or the like.

  A cooling water channel 51 similar to the surface of the separator 11 on the side opposite to the power generation unit 12 is formed on the surface of the separator 13 on the side opposite to the power generation unit 12. In the present embodiment, since the dimple portion is formed in the folded portion of the cooling water channel 51, the shape of the separator 13 side surface of the separator 13 is constrained by the shape of the cooling water channel 51 on the back surface. There is no.

  7 is a cross-sectional view taken along line BB in FIG. As shown in FIG. 7, the dimple portion 54 has a plurality of protrusions 55, the dimple portion 56 has a plurality of protrusions 57, and the dimple portion 58 has a plurality of protrusions 59. Yes.

  Next, the operation of the fuel cell 200 will be described. First, the fuel gas is supplied to the fuel gas inlet manifold 23a by the fuel gas supply means 203. The oxidant gas supply means 202 supplies the oxidant gas to the oxidant gas inlet manifold 22a. Further, cooling water is supplied to the cooling water inlet manifold 21 a by the cooling water circulation pump 201.

  The fuel gas is supplied to the fuel gas passage 53 from the fuel gas inlet manifold 23a. In this case, the fuel gas is supplied to the anode 33 while flowing through the fuel gas channel 53. Hydrogen in the fuel gas supplied to the anode 33 is converted into hydrogen ions. The converted hydrogen ions are conducted through the electrolyte membrane 31 and reach the cathode 32.

  The oxidant gas is supplied to the oxidant gas flow path 52 from the oxidant gas inlet manifold 22a. In this case, the oxidant gas is supplied to the cathode 32 while flowing through the oxidant gas flow path 52. Oxygen contained in the oxidant gas supplied to the cathode 32 reacts with hydrogen ions reaching the cathode 32 to generate water and electric power. Power generation of the fuel cell 200 is performed by the above process.

  The fuel gas that has not been consumed in the anode 33 flows through the fuel gas passage 53 and is discharged from the fuel gas outlet manifold 23b. The oxidant gas that has not been consumed in the cathode 32 flows through the oxidant gas flow path 52 and is discharged from the oxidant gas outlet manifold 22b. Further, the cooling water is supplied from the cooling water inlet manifold 21 a to the cooling water passage 51. The cooling water cools the fuel cell 200 heated by the power generation reaction while flowing through the cooling water channel 51. The cooling water flows through the cooling water passage 51, is then discharged from the cooling water outlet manifold 21 b, and is supplied to the cooling water passage 51 again via the cooling water circulation pump 201.

  As shown in FIGS. 2 and 6, the flow direction of the fuel gas in the straight portion of the fuel gas passage 53 and the flow direction of the oxidant gas in the straight portion of the oxidant gas passage 52 are opposite to each other. In this case, the fuel gas concentration distribution and the oxidant gas concentration distribution do not overlap. Therefore, the dispersion | variation in the electric power generation distribution in the electric power generation part 12 is suppressed. As a result, the power generation efficiency of the fuel cell 200 is improved.

  Then, the effect which the flow direction of oxidant gas and cooling water brings is demonstrated. FIG. 8 is a schematic diagram showing the flow directions of the oxidant gas and the cooling water. The solid line arrows in FIG. 8 indicate the flow direction of the cooling water, and the broken line arrows in FIG. 8 indicate the flow direction of the oxidant gas. As shown in FIG. 8, the cooling water and the oxidant gas flow while meandering in the same direction on the front and back surfaces of the separator 11.

  In the vicinity of the oxidant gas inlet manifold 22a as shown in the region 61 of FIG. 8, the cathode 32 and the electrolyte membrane 31 tend to be dried by the oxidant gas. This is because the oxidant gas supplied from the oxidant gas supply means 202 does not contain water vapor. However, the cooling water has the lowest temperature near the region 61. This is because the cooling water is not yet heated by the power generation reaction of the fuel cell 200 in the vicinity of the region 61. Accordingly, the temperature of the region 61 decreases. Thereby, drying of the cathode 32 and the electrolyte membrane 31 by the oxidant gas can be suppressed.

  Further, in the first folded region of the oxidant gas flow path 52 as shown in the region 62 of FIG. 8, the temperature of the cooling water rises because the cooling water is heated by the power generation reaction of the fuel cell 200. Yes. Thereby, liquefaction of water generated by the power generation reaction is suppressed at the cathode 32 in the region 62. Therefore, liquefaction of water generated by the power generation reaction is suppressed. In the fuel cell 200 according to the present embodiment, the retention of the liquid water in the region 62 is suppressed in the fuel cell 200 according to the present embodiment, although it is difficult to remove the remaining liquid water in the folded portion of the oxidant gas flow path such as the region 62.

  Further, in the second folded region of the oxidant gas flow path 52 as shown in the region 63 of FIG. 8, the temperature of the cooling water further increases. Thereby, liquefaction of water at the cathode 32 in the region 63 is suppressed. Therefore, stagnation of liquid water in the region 63 is suppressed. From the above, stagnation of liquid water is suppressed in any of the oxidant gas flow paths 52. Therefore, the dispersion | variation in the reactive gas flow volume between electric power generation cells is suppressed.

  In this embodiment, the cooling water passage 51, the oxidant gas passage 52, and the fuel gas passage 53 are reciprocated once and a half in the X direction. In that case, the effect of the present invention can be obtained if the flow direction of the oxidant gas and the flow direction of the cooling medium are opposite to each other.

  In this embodiment, the separator 11 corresponds to a first separator, the separator 13 corresponds to a second separator, the groove portion 42 corresponds to a concave portion on one side, and the groove portion 41 corresponds to a concave portion that forms a cooling medium. The dimple portions 54, 56, and 58 correspond to the folded portion and the manifold communication portion, and the cooling water circulation pump 201 corresponds to the cooling medium supply unit.

  Subsequently, a fuel cell 200a according to a second embodiment of the present invention will be described. The fuel cell 200a is different from the fuel cell 200 according to the first embodiment in that the cooling water inlet manifold 21a and the oxidant gas inlet manifold 22a are arranged in reverse, and the cooling water outlet manifold 21b and the oxidant gas outlet. The manifold 22b is arranged in reverse. FIG. 9 is a schematic diagram showing the flow directions of oxidant gas and cooling water in the fuel cell 200a. The solid line arrows in FIG. 9 indicate the flow direction of the cooling water, and the broken line arrows in FIG. 9 indicate the flow direction of the oxidant gas.

  As shown in FIG. 9, the oxidant gas inlet manifold and the cooling water inlet manifold are adjacent to each other even if the oxidant gas inlet manifold and the cooling water inlet manifold are arranged in reverse. Thereby, the flow direction of oxidant gas and the flow direction of cooling water correspond. As a result, the effects of the present invention can also be obtained in the fuel cell 200a according to the second embodiment.

  If the flow direction of the oxidant gas and the flow direction of the cooling water coincide with each other because the inlet manifold for the oxidant gas and the inlet manifold for the cooling water are adjacent to each other, the manifolds for the oxidant gas, the cooling water, and the fuel gas The position of is not limited. The flow direction in the straight portion of the oxidant gas flow path and the flow direction in the straight line portion of the fuel gas flow path are preferably opposite to each other.

  In the above embodiment, the flow direction of the oxidant gas and the flow direction of the cooling medium coincide with each other. However, in the fuel cell in which water is generated on the anode side by the power generation reaction, the flow direction of the fuel gas The effect of the present invention can be obtained by matching the flow direction of the cooling medium.

  Furthermore, in the above embodiment, the position of the oxidant gas outlet manifold in the vertical direction is not defined, but the oxidant gas outlet manifold is preferably lower in the vertical direction than the oxidant gas inlet manifold. In this case, it is because discharge of the liquid water generated in the oxidant gas flow path is promoted.

1 is a schematic diagram showing an overall configuration of a fuel cell system according to a first embodiment. It is a disassembled perspective view of the fuel cell which concerns on a present Example. It is the sectional view on the AA line of FIG. It is a top view which shows the surface on the opposite side to the electric power generation part of a separator. It is a top view which shows the surface by the side of the electric power generation part of a separator. It is a top view which shows the surface by the side of the electric power generation part of a separator. FIG. 3 is a sectional view taken along line BB in FIG. 2. It is a schematic diagram which shows the flow direction of oxidizing agent gas and cooling water. It is a schematic diagram which shows the flow direction of oxidant gas and cooling water in the fuel cell which concerns on 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 13 Separator 12 Electric power generation part 21a Cooling water inlet manifold 22a Oxidant gas inlet manifold 23a Fuel gas outlet manifold 31 Electrolyte membrane 51 Cooling water flow path 52 Oxidant gas flow path 53 Fuel gas flow paths 54, 56, 58 Dimple part 55, 57, 59 Projection 100, 100a Fuel cell 200 Fuel cell system 201 Cooling water circulation pump 202 Oxidant gas supply means 203 Fuel gas supply means

Claims (4)

A first separator in which at least a part of the cross-section is corrugated, a concave portion on one surface forms an oxidant gas flow path, and a concave portion adjacent to the concave portion on the one surface on the other surface forms a cooling medium flow path;
The oxidant gas flow path and the cooling medium flow path have a serpentine shape that is folded back in the same direction by a turn-back portion, and are connected to the manifold via a manifold communication portion on both the inlet side and the outlet side,
The manifold communication portion and the folded portion are composed of a plurality of protrusions formed in a lattice point shape,
The manifold on the inlet side of the cooling medium flow path is adjacent to the manifold on the inlet side of the oxidant gas flow path and the manifold communication portion,
The fuel cell, wherein the oxidant gas flowing through the oxidant gas flow path and the cooling medium flowing through the cooling medium flow path flow in the same direction. A fuel gas flow path is formed on the other surface, and a second separator facing the first separator across the power generation unit including the electrolyte membrane is provided.
The fuel gas flow path has a serpentine shape turned back by a turn-back portion, and is connected to the manifold via a manifold communication portion on both the inlet side and the outlet side,
The manifold on the inlet side of the fuel gas flow path is adjacent to the manifold on the outlet side of the cooling medium flow path or the oxidant gas flow path,
2. The fuel cell according to claim 1, wherein the flow direction of the fuel gas in the straight portion of the fuel gas flow path is opposite to the flow direction of the straight portion of the oxidant gas. 3. The fuel cell according to claim 1, wherein the electrolyte membrane is made of a solid polymer having hydrogen ion conductivity. A fuel cell according to claim 2 or 3,
Cooling medium supply means for supplying a cooling medium to a manifold on the inlet side of the cooling medium flow path;
An oxidant gas supply means for supplying an oxidant gas to the manifold on the inlet side of the oxidant gas flow path;
A fuel cell system comprising fuel gas supply means for supplying fuel gas to a manifold on the inlet side of the fuel gas flow path.

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