JP2009146859A - Fuel cell and fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent blockage of a gas flow passage by formed water at the time of start-up of a fuel cell. <P>SOLUTION: A fuel cell stack is longitudinally placed so that a stacking direction becomes a vertical direction. In the respective cells 10 constituting the fuel cell stack, a cathode flow passage 18 is positioned on the lower side, while an anode gas flow passage 19 is positioned on the upper side. The cathode gas flow passage 18 positioned on the lower side is larger in a flow passage cross-sectional area than the anode gas flow passage 19 positioned on the upper side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell and a fuel cell stack in which a plurality of fuel cells are stacked.

  A fuel cell receives fuel gas on the anode (fuel electrode) side and air on the cathode (oxygen electrode) side, and proceeds with an electrochemical reaction using hydrogen and oxygen contained in both gases. Is generated. Accompanying this electrochemical reaction, water or water vapor (hereinafter also referred to as “product water”) is generated on the cathode side. When the amount of generated water increases, the supply of air to the cathode may be hindered. As a result, the electrochemical reaction is not performed smoothly, and the power generation capacity is reduced. Therefore, in the fuel cell, it is attempted to efficiently discharge generated water by various methods (see, for example, Patent Document 1).

  This type of fuel cell is generally used as a fuel cell stack by alternately laminating a plurality of electrolyte membrane-electrode assemblies and separators. In-vehicle fuel cell stacks such as automobiles are usually mounted in a horizontal orientation with the above stacking direction as the horizontal direction. On the other hand, a vertical fuel cell stack in which the stacking direction is the gravitational direction has been proposed for the purpose of satisfactory mounting on a front box of a vehicle (see Patent Document 2).

JP 2004-79196 A JP 2003-173790 A

  In the conventional vertical fuel cell stack, the generated water cannot be efficiently discharged when the operation is stopped, and the gas flow path on one side of the fuel cell may be blocked at the time of startup. When the operation is stopped, the water generated at the time of power generation moves downward in the direction of gravity, and the water is stored in the gas flow channel located on the lower side in the fuel cell by vertical installation. At the time of start-up, the gas flow path located on the lower side is blocked.

  An object of the present invention is to prevent a gas flow path from being blocked by generated water when a fuel cell is started.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A fuel cell,
A membrane electrode assembly that sandwiches an electrolyte membrane between two electrodes, the membrane electrode assembly being disposed so that the first surface of the assembly is on the lower side and the second surface of the assembly is on the upper side; ,
A first separator facing the first surface and forming a first gas flow path for flowing a first reactive gas in a direction along the first surface;
A second separator facing the second surface and forming a second gas flow path for flowing a second reactive gas in a direction along the second surface;
The fuel cell, wherein the first gas channel is configured to have a channel cross-sectional area larger than that of the second gas channel.

  According to the fuel cell of Application Example 1, the first separator that forms the first gas flow path is located below the membrane electrode assembly, and the second gas flow is located above the membrane electrode assembly. The second separator forming the path will be located. Since the first gas channel is configured to have a larger channel cross-sectional area than the second gas channel, the first gas channel located in the lower direction of the membrane electrode assembly However, the channel cross-sectional area becomes larger than that of the second gas channel located above the membrane electrode assembly. When the operation is stopped, water generated at the time of power generation moves downward in the direction of gravity due to gravity. Therefore, the water on the second surface side passes through the electrolyte membrane and is below the first gas flow path. The water on the surface side remains as it is below the first gas flow path. However, as described above, since the first gas flow path in the downward direction of the membrane electrode assembly has a large flow path cross-sectional area, there is little possibility that the first gas flow path is completely blocked by the generated water. . Therefore, the fuel cell of Application Example 1 has an effect that a gas flow path can be ensured when the fuel cell is started.

[Application Example 2]
The fuel cell according to Application Example 1, wherein the first reaction gas is an oxidant gas, and the second reaction gas is a fuel gas. According to this configuration, the first gas flow path through which the oxidant gas flows has a larger cross-sectional area of the flow path, so that there is less pressure loss during power generation. In general, the oxidant gas is supplied with air compressed by a compressor, so that the power generation efficiency can be increased as the pressure loss is reduced in the first gas flow path. On the other hand, since the fuel gas is supplied from the high-pressure tank, the power generation efficiency does not change so much depending on the pressure loss in the second gas flow path. For this reason, in the fuel cell described in Application Example 2, it is possible to reduce the pressure loss of the first gas flow path through which the oxidant gas flows, and to increase the power generation efficiency.

[Application Example 3]
The fuel cell according to Application Example 1 or 2, wherein the first gas flow path includes a porous body. According to this configuration, the diffusibility of the reaction gas can be enhanced by the porous body in the first gas flow path. On the other hand, the porous body has a disadvantage that the amount of generated water is large at the time of stoppage. However, due to the configuration of the fuel cell described in Application Example 1, even if there is a large amount of residual water, the gas flow path at the time of startup is reduced. Can be secured.

[Application Example 4]
The fuel cell according to Application Example 3, wherein the porous body has hydrophilicity. According to this configuration, since the porous body has hydrophilicity, water can be further stored on the wall surface of the first gas flow path with the separator.

[Application Example 5]
5. The fuel cell according to Application Example 3 or 4, wherein the fuel cell includes a first gas introduction / extraction section that introduces / extracts the first reaction gas from an end surface of the porous body. ,Fuel cell. According to this configuration, since the first reaction gas can be introduced / extracted from the end face of the porous body, even if the generated water accumulates on the lower side in the gravity direction of the first gas flow path when the operation is stopped, Therefore, the first reaction gas flow path can be ensured reliably.

[Application Example 6]
The fuel cell according to Application Example 5, wherein the first separator is provided on a joint surface with the porous body, and the first reaction gas is introduced into the porous body from a direction perpendicular to the joint surface. A fuel cell, comprising a second gas introduction / extraction part that attempts to exit. According to this configuration, since the second gas inlet / outlet part provided in the first separator is connected to the porous body, the generated water can be favorably discharged from the porous body part by capillary action. .

[Application Example 7]
A fuel cell stack in which a plurality of fuel cells according to any one of Application Examples 1 to 6 are stacked as a single cell. In the fuel cell stack having such a configuration, a plurality of fuel cells are stacked in the vertical direction. Also with this configuration, as in the fuel cell of Application Example 1, the gas flow path can be secured when the fuel cell stack is started.

Next, embodiments of the present invention will be described based on examples.
A. First embodiment:
A-1. Fuel cell stack configuration:
FIG. 1 is an explanatory diagram showing the configuration of a fuel cell stack 100 according to the first embodiment of the present invention. The fuel cell stack 100 realizes clamping by a pair of end plates 120 and 130, a stack 110 of fuel cells to be described later, a pair of end plates 120 and 130 that sandwich the stack 110 from both ends in the stacking direction. Are provided with four sets of bolts 141 and nuts 142 for fastening the pair of end plates 120 and 130 to each other. In the fuel cell stack 100, manifold holes M1 to M6 are formed as a plurality of through holes for supplying or discharging anode gas (fuel gas containing hydrogen), cathode gas (oxidant gas), or the like to the stack 110. Has been. Anode gas and cathode gas are supplied to the inside of the laminate 110 from the outside through a manifold hole M1 to M6 from an external hydrogen tank, compressor, or the like (not shown).

  The coordinate system of FIG. 1 represents each direction assumed when the fuel cell stack 100 is mounted on a vehicle such as an automobile. The up-down direction indicates the up-down direction of the vehicle, and the front-rear direction and the left-right direction indicate the front-rear direction and the left-right direction of the vehicle, respectively. Note that the front-rear direction and the left-right direction need not be limited to this direction. For example, the front-rear direction can be changed to the right-left direction, and the left-right direction can be changed to the front-rear direction. The vertical direction is limited to this direction. That is, in the vehicle, the fuel cell stack 100 is mounted vertically so that the stacking direction of the fuel cells is the vertical direction. Here, the vertical direction is preferably the gravitational direction, but is not necessarily the gravitational direction, and may be any direction above the horizontal direction and below the horizontal direction.

A-2. Fuel cell configuration:
FIG. 2 is an explanatory diagram schematically showing a cross section of the fuel battery cell 10. The fuel cell 10 is a fuel cell as a single cell constituting the stacked body 110 of the fuel cell stack 100. As shown in the figure, the fuel cell 10 includes a MEA 14 (Membrane Electrode Assembly), gas diffusion layers 13 a and 13 b, gas flow paths 18 and 19, and a separator 30. The gas diffusion layers 13a and 13b are disposed on both surfaces of the MEA 14. A member composed of the MEA 14, the gas diffusion layer 13a, and the gas diffusion layer 13b is referred to as MEGA15. The gas flow paths 18 and 19 are disposed between the MEGA 15 and the separator 30.

  The MEA 14 includes a cathode electrode catalyst layer 12 a and an anode electrode catalyst layer 12 b on the surface of the electrolyte membrane 11. The electrolyte membrane 11 is a thin film of a solid polymer material that has proton conductivity and exhibits good electrical conductivity in a wet state, and is smaller than the outer shape of the separator 30 and larger than the outer shapes of gas flow paths 18 and 19 to be described later. It is formed in a rectangle. The electrolyte membrane 11 is, for example, Nafion. The cathode electrode catalyst layer 12a and the anode electrode catalyst layer 12b formed on the surface of the electrolyte membrane 11 carry a catalyst that promotes an electrochemical reaction, for example, platinum.

  The gas diffusion layers 13a and 13b are carbon porous bodies having a porosity of about 80%, and are formed of, for example, carbon cloth or carbon paper. The gas diffusion layers 13a and 13b are integrated with the MEA 14 by bonding to form the MEGA 15. The cathode electrode catalyst layer 12a and the gas diffusion layer 13a, and the anode electrode catalyst layer 12b and the gas diffusion layer 13b respectively correspond to “electrodes” of the present invention. The MEGA 15 corresponds to the “membrane electrode assembly” of the present invention. The gas diffusion layer 13a is disposed on the cathode side of the MEA 14, and the gas diffusion layer 13b is disposed on the anode side. The gas diffusion layer 13a diffuses the cathode gas in the thickness direction and supplies it to the entire surface of the cathode electrode catalyst layer 12a. The gas diffusion layer 13b diffuses the anode gas in the thickness direction and supplies it to the entire surface of the anode electrode catalyst layer 12b. The gas diffusion layers 13a and 13b have a relatively low porosity because they mainly aim to diffuse the gas in the thickness direction.

  The coordinate system in FIG. 1 corresponds to FIG. 1, and the vertical direction indicates the vertical direction of the vehicle. That is, the cathode side surface 14A of the MEA 14 faces the lower side of the vehicle, and the anode side surface 14A of the MEA 14 faces the upper side of the vehicle. The cathode side surface 14A corresponds to the “first surface” of the present invention, and the anode side surface 14B corresponds to the “second surface” of the present invention.

  The separator 30 is made of a conductive metal material such as stainless steel, titanium, or titanium alloy, and has a rectangular plate shape in this embodiment. The separator 30 faces the cathode side surface 14A of the MEA 14, thereby providing a gas flow path (hereinafter also referred to as “cathode gas flow path”) 18 through which the cathode gas flows in a direction along the surface 14A. Forming. Further, the separator 30 faces the anode surface 14B of the MEA 14 so that the anode gas flows in a direction along the surface 14B (hereinafter also referred to as “anode gas channel” if necessary) 19. Is forming. The cathode gas flow path 18 corresponds to the “first gas flow path” of the present invention, and the anode gas flow path 19 corresponds to the “second gas flow path” of the present invention.

  The height of the cathode gas channel 18 (height in the stacking direction), that is, the distance t1 between the first surface 14A of the MEGA 15 and the separator 30 is the height of the anode gas channel 19 (height in the stacking direction). ), That is, larger than the distance t2 between the second surface 14B of the MEGA 15 and the separator 30. That is, the cathode gas channel 18 has a channel cross-sectional area larger than that of the anode gas channel 19. The distance t1 is 0.4 [mm], for example, and the distance t2 is 0.2 [mm], for example. The distances t1 and t2 are not limited to the numerical values described as long as the condition that the cross-sectional area of the cathode gas channel 18 is larger than the cross-sectional area of the anode gas channel 19 is satisfied. It can also be a size.

  Porous portions 21 and 22 are disposed inside the gas flow paths 18 and 19. The porous body portions 21 and 22 are configured using a porous body. As the porous body, a foamed sintered body is used in this embodiment. As the foam sintered body, a metal or ceramic-containing foam sintered body is used. In addition, it is good also as expanded metal etc. instead of a foaming sintered compact. The diffusibility of the cathode gas and the anode gas can be enhanced by the porous body portions 21 and 22.

  The porous body portion 21 provided in the cathode gas channel 18 can be hydrophilic by performing a hydrophilic treatment. The hydrophilic treatment method is not particularly limited, and a known hydrophilic treatment method can be appropriately employed. For example, a metal oxide such as alumina or silica, a hydrophilic resin such as a water-soluble epoxy resin, or a hydrophilic substance such as activated carbon may be blended in the powder raw material for the porous portion. Furthermore, a gold plating process may be performed as a hydrophilic process.

  In the present embodiment, the porous body 22 on the anode side is not subjected to hydrophilic treatment. Instead of this, the porous body portion 22 may be configured to perform a hydrophilic treatment. In the present embodiment, as shown in the drawing, the size of the bonding surface of the porous body portions 21 and 22 is the same as that of the first surface 14A and the second surface 14B of the MEGA 15, but instead of this, The area may be smaller than that of the first surface 14A and the second surface 14B. In other words, the porous body portions 21 and 22 may have a configuration provided over the entire gas flow paths 18 and 19 as in the present embodiment. , 19 may be provided.

  On the cathode side surface of the separator 30, holes 23 and 24 serving as cathode gas inlets and outlets to the gas flow path 18 are provided. The holes 23 and 24 are finally communicated with the cathode gas one of the manifold holes M1 to M6 shown in FIG. On the other hand, the anode side surface of the separator 30 is provided with holes 25 and 26 that serve as the inlet and outlet of the anode gas to the gas flow path 19. The holes 25 and 26 are finally communicated with the anode gas for one of the manifold holes M1 to M6 shown in FIG. The cathode-side holes 23 and 24 and the anode-side holes 25 and 26 are provided at portions that do not overlap the MEGA 15 when viewed along the stacking direction.

  With the above configuration, the cathode gas is discharged from the hole 23 on the cathode side, and as indicated by an arrow A, the cathode gas travels from the outer space of the first end surface 21a of the porous body portion 21 toward the first end surface 21a. Go ahead. The anode gas passes through the porous body portion 21, and then exits from the second end surface (end surface facing the first end surface 21a) 21b of the porous body portion 21 as shown by an arrow B, and is formed in the hole on the cathode side. Invade part 24. Thus, the cathode gas can be introduced / derived from the end faces 21a and 21b (that is, from the direction perpendicular to the end faces 21a and 21b) with respect to the porous body portion 21. Similarly, on the anode side, the anode gas can be introduced / derived from the end surfaces 22a and 22b (that is, from the direction perpendicular to the end surfaces 22a and 22b) with respect to the porous body portion 22 by the holes 25 and 26.

  As described above, the stack 110 of the fuel cell stack 100 shown in FIG. 1 is formed by stacking a plurality of the fuel cells 10 in the vertical direction. That is, the fuel cell stack 100 is configured by joining the separator 30-cathode gas flow path 18-MEGA 15-anode gas flow path 19-separator 30 and repeating this. The separator 30 corresponds to the “first separator” and the “second separator” in the present invention. The holes 23 and 24 are “first gas introduction / extraction portions” in the present invention.

A-3. Effect:
According to the fuel cell stack 100 of the present embodiment configured as described above, the cathode gas flow path 18 is located below the MEGA 15 and the anode gas flow path 19 is located above the MEGA 15. The cathode gas flow path 18 in the downward direction of the MEGA 15 has a flow path cross-sectional area larger than that of the anode gas flow path 19 in the upward direction of the MEGA 15. When the operation is stopped, the water generated during power generation moves downward in the direction of gravity due to gravity, so the water Wu (see FIG. 2) on the second surface 14B side of the MEA 14 passes through the electrolyte membrane and passes through the cathode gas channel. Below 18, the water on the first surface 14 </ b> A side of the MEA 14 accumulates directly below the cathode gas flow path 18. W in FIG. 2 is the accumulated water. However, in the fuel cell stack 100, as described above, the cathode gas flow path 18 in the downward direction of the MEGA 15 has a large flow cross-sectional area, so that the cathode gas flow path 18 is completely blocked by the stored water W. There is little possibility that Therefore, the fuel cell stack 100 of the present embodiment has an effect that the gas flow path can be secured at the time of startup. Even when the water W is frozen in the cold season, the gas flow path can be secured.

  Further, in the fuel cell stack 100 of this embodiment, since the porous body portion 21 provided in the cathode gas flow path 18 has a hydrophilic structure, water W is supplied to the wall surface of the anode gas flow path 19 with the separator 30. More can be stored. For this reason, a gas flow path can be secured more at the time of starting.

  Furthermore, according to the present embodiment, the cathode gas flow path 18 through which the cathode gas (oxidant gas) flows has a larger flow path cross-sectional area, so that there is less pressure loss during power generation. The cathode gas is supplied with air compressed by a compressor, but the power generation efficiency can be increased as the pressure loss in the cathode gas flow path 18 is smaller. On the other hand, since the anode gas (fuel gas) is supplied from a high-pressure tank (not shown), the power generation efficiency does not change so much depending on the pressure loss in the anode gas passage 19. For this reason, in the fuel cell stack 100 of the present embodiment, the pressure loss of the cathode gas passage 18 through which the cathode gas flows can be reduced, and the power generation efficiency can be increased.

B. Second embodiment:
FIG. 3 is an explanatory view schematically showing a cross section of the fuel cell 210 provided in the fuel cell stack according to the second embodiment of the present invention. This figure corresponds to the single cell of FIG. 2 in the first embodiment. As shown in the figure, the fuel cell 210 is different from the fuel cell 10 of the first embodiment in the following points 1) and 2).

1) The separator 30 further includes a pair of holes (hereinafter referred to as “inner holes”) 223 and 224 serving as cathode gas inlets and outlets to the cathode gas flow path 18 on the cathode side surface of the separator 30.
2) A pair of hole portions (hereinafter referred to as “inner hole portions”) 225 that serve as cathode gas inlet / outlet ports to the anode gas flow path 19 by removing the hole portions 25 and 26 provided on the anode side surface of the separator 30. , 226.

  The configuration other than the above 1) and 2) is the same as that of the fuel cell 10 of the first embodiment. In addition, the same number was attached to the same part as 1st Example. In addition, the fuel cell 210 of the present embodiment is also stacked in the vertical direction in the same manner as the fuel cell 10 of the first embodiment to constitute a fuel cell stack.

  The cathode-side inner holes 223 and 224 and the anode-side inner holes 225 and 226 are located on the inner side (inner side on the surface of the separator 30) than the cathode-side holes 23 and 24 provided in the first embodiment. It is provided and is provided in a portion overlapping with MEGA 15 when viewed along the stacking direction. The inner holes 223 and 224 on the cathode side finally communicate with the cathode gas one of the manifold holes M1 to M6 shown in FIG. The inner holes 225 and 226 on the anode side communicate with the anode gas for the anode gas among the manifold holes M1 to M6 shown in FIG.

  With such a configuration, the cathode gas / anode gas can be introduced into / derived from the porous body portions 21 and 22 from the direction perpendicular to the joint surfaces 30a and 30b between the separator 30 and the porous body portions 21 and 22. In addition, since the inner hole portions 223 and 224 on the cathode side and the porous body portion 21 are connected, and the inner hole portions 225 and 226 on the anode side and the porous body portion 22 are connected, capillary action is caused. Thus, the generated water can be discharged well from the porous body portions 21 and 22.

  According to the second embodiment configured as described above, with respect to the porous body portion 21 provided in the cathode gas flow path 18, the hole portions 23 and 24 are connected to the inner hole portions 223 and 224 from the end surfaces 21 a and 21 b. Thus, the cathode gas can be introduced / derived from the direction perpendicular to the joining surface 30a. That is, the cathode gas can be introduced into and extracted from both the direction perpendicular to the end surfaces 21a and 21b and the direction perpendicular to the bonding surface 30a with respect to the porous body portion 21. In addition, the cathode gas can be introduced / derived from the direction perpendicular to the bonding surface 30b by the inner hole portions 225 and 226 with respect to the porous body portion 22 provided in the anode gas flow path 19.

  Therefore, according to the second embodiment, as in the first embodiment, the gas flow path can be secured at startup. Furthermore, as described above, the generated water can be discharged well from the porous body parts 21 and 22 by the capillary phenomenon by the inner hole parts 223 and 224 and the inner hole parts 225 and 226, and nevertheless when the operation is stopped. Even if the water W collected in the cathode gas flow path 18 below in the direction of gravity closes the inner holes 223 and 224, the gas flow path can be secured by the holes 23 and 24. In other words, the generated water can be discharged well from the porous body portions 21 and 22 by capillary action, and even if the generated water is stored in the gas flow path when the operation is stopped, It is possible to achieve a balance with securing. The inner hole portions 223 and 224 are “second gas introduction / extraction portions” in the present invention.

C. Variations:
The present invention is not limited to the above-described embodiments and modifications, and can be carried out in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) In the first embodiment, the holes 23, 24, 25, and 26 are provided on both the surfaces 30a and 30b of the separator 30 (that is, on both the cathode side and the anode side). The holes 25 and 26 are not limited to this configuration, and any configuration may be used as long as the anode gas can be introduced into the porous body portion 22. The cathode-side holes 23 and 24 may be replaced with other configurations as long as the cathode gas can be introduced / extracted from the end faces 21a and 21b of the porous body portion 21. For example, portions other than the separator 30 It is good also as a structure which introduces / extracts gas from. In the second embodiment, the cathode-side holes 23 and 24 may be replaced with other configurations as long as the cathode gas can be introduced and discharged from the end surfaces 21a and 21b of the porous body 21. For example, it is good also as a structure which introduces / extracts gas from parts other than the separator 30. FIG. Further, the cathode side holes 23 and 24 may be removed from the configuration of the second embodiment.

(2) In each of the above embodiments, the cathode side surface 14A of the MEA 14 faces the lower side of the vehicle, and the anode side surface 14A of the MEA 14 faces the upper side of the vehicle, but instead, the cathode side of the MEA 14 The surface 14A may face the upper side of the vehicle, and the anode side surface 14A of the MEA 14 may face the lower side of the vehicle. In this case, the anode gas is preferably introduced / derived from at least the end face with respect to the porous body provided in the anode gas flow path.

(3) In each of the above-described embodiments, the cathode-side porous body portion 21 is configured to have hydrophilicity. However, instead of this, a configuration having no hydrophilicity may be employed. In each embodiment, both the cathode gas channel 18 and the anode gas channel 19 are provided with the porous body portions 21 and 22, but instead, the cathode gas channel 18 and the anode gas channel 19 are provided. It is good also as a structure provided with a porous body part in any one of these, and it is good also as a structure which is not provided with a porous body part in both.

(4) In each of the above-described embodiments, the configuration is a fuel cell stack in which a plurality of fuel cells are stacked. Alternatively, a configuration as a fuel cell including only one fuel cell may be used. Good.

(5) In each of the above-described embodiments, the “first separator” and the “second separator” are configured to be shared by one separator 30, but may be configured separately instead. Moreover, although the separator 30 was plate-shaped, it is good also as a separator provided with two or more convex parts, such as the linear rib which comprises a straight groove | channel, and a cube, instead of this. Also in this case, the cathode gas channel and the anode gas channel formed by the separator have a larger channel cross-sectional area of the gas channel located on the lower side than that of the gas channel located on the upper side. It is configured to satisfy the condition.

(6) In each of the above embodiments, the fuel cell is a solid polymer fuel cell. However, the fuel cell is not necessarily a solid polymer fuel cell, and can be applied to various types of fuel cells.

(7) In each of the embodiments described above, the fuel cell stack is mounted on a vehicle such as an automobile, but instead, it may be mounted on a vehicle other than an automobile such as a train. Moreover, it is not necessary to restrict to a vehicle, It is good also as another mobile body of a ship.

It is explanatory drawing which shows the structure of the fuel cell stack 100 in 1st Example of this invention. 2 is an explanatory view schematically showing a cross section of a fuel battery cell 10. FIG. It is explanatory drawing which shows typically the cross section of the fuel cell 210 with which the fuel cell stack in 2nd Example of this invention is equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 11 ... Electrolyte membrane 12a ... Cathode electrode catalyst layer 12b ... Anode electrode catalyst layer 13a ... Gas diffusion layer 13b ... Gas diffusion layer 14A ... 1st surface 14B ... 2nd surface 18 ... Cathode gas flow path 19 ... Anode gas flow path 21, 22 ... Porous part 23, 24 ... Hole 25, 26 ... Hole 30 ... Separator 100 ... Fuel cell stack 110 ... Laminate 120 ... End plate 141 ... Bolt 142 ... Nut 210 ... Fuel cell Cells 223, 224 ... inner hole 225, 226 ... inner hole

Claims (7)

A fuel cell,
A membrane electrode assembly that sandwiches an electrolyte membrane between two electrodes, the membrane electrode assembly being disposed so that the first surface of the assembly is on the lower side and the second surface of the assembly is on the upper side; ,
A first separator facing the first surface and forming a first gas flow path for flowing a first reactive gas in a direction along the first surface;
A second separator facing the second surface and forming a second gas flow path for flowing a second reactive gas in a direction along the second surface;
The fuel cell, wherein the first gas channel is configured to have a channel cross-sectional area larger than that of the second gas channel. The fuel cell according to claim 1,
The first reaction gas is an oxidant gas;
The fuel cell, wherein the second reaction gas is a fuel gas. The fuel cell according to claim 1 or 2,
The first gas channel is a fuel cell having a porous body. The fuel cell according to claim 3, wherein
The porous body is a fuel cell having hydrophilicity. The fuel cell according to claim 3 or 4, wherein
A fuel cell comprising a first gas introduction / extraction section for introducing the first reaction gas from an end face of the porous body to the porous body. The fuel cell according to claim 5, wherein
The first separator is
A fuel cell, comprising: a second gas introduction / extraction part that is provided on a joint surface with the porous body and that introduces / extracts the first reaction gas to / from the porous body from a direction perpendicular to the joint surface.   A fuel cell stack in which a plurality of fuel cells according to claim 1 are stacked as a single cell.

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