JP2009218190A - Fuel cell - Google Patents

Abstract

A technique for suppressing a decrease in power generation efficiency in a fuel cell is provided.
[Solution]
A fuel cell comprising: a power generation body in which electrodes are disposed on both surfaces of an electrolyte membrane; a gas flow path forming member made of a porous body disposed on at least one surface of the power generation body; A separator disposed on a surface opposite to a surface on which the power generation body is disposed, and the gas flow path forming member is disposed on the first member and the power generation body side and is more hydrophilic than the first member. A high second member.
[Selection] Figure 3

Description

  The present invention relates to a fuel cell.

  In a fuel cell, water is generated by an electrochemical reaction between hydrogen and oxygen during power generation (hereinafter, the generated water is also referred to as “generated water”). When such generated water stays in the vicinity of the electrolyte membrane (so-called flooding), the supply of the reaction gas is delayed and the fuel cell performance may be deteriorated.

  By the way, in a fuel cell, a power generation body in which electrodes are disposed on both surfaces of an electrolyte membrane, a gas diffusion layer disposed on both surfaces of the power generation body, and a porous body flow for supplying reaction gas to the power generation body Some include a path forming member and a separator that separates the anode gas and the cathode gas and collects electricity generated by each electrode (for example, see Patent Documents 1 and 2).

  In such a fuel cell, a hydrophilic portion having a hydrophilic property is provided on the surface of the porous channel forming member that contacts the separator, and the generated water staying in the vicinity of the electrolyte membrane is moved to the porous channel forming member. Thus, a technique for suppressing flooding by discharging generated water by the flow of a reactive gas has been proposed (see, for example, Patent Document 3).

JP 2005-310633 A JP 2007-87768 A JP 2006-134582 A

  As described above, the produced water is discharged out of the fuel cell by the flow of the reaction gas. Since the dry reaction gas is introduced near the inlet of the reaction gas (upstream of the flow of the reaction gas), the generated water generated by the power generator is easily discharged. On the other hand, in the vicinity of the outlet of the reactive gas (downstream of the reactive gas flow), the flow rate of the reactive gas becomes slow, so that the generated water is difficult to be discharged. Thus, the discharge state of generated water is not uniform in the surface direction of the power generator. Therefore, as in the fuel cell described in Patent Document 3 described above, if a hydrophilic layer is provided on the entire surface of the porous body flow passage forming member that contacts the separator, drainage of generated water generated by the power generation body is promoted. Thus, in the vicinity of the reaction gas inlet, the electrolyte membrane may be dried and the power generation efficiency may be reduced.

  This invention is made | formed in view of such a subject, and it aims at providing the technique which suppresses the fall of the power generation efficiency in a fuel cell.

  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 power generator in which electrodes are arranged on both sides of the electrolyte membrane;
A gas flow path forming member made of a porous material, disposed on at least one surface of the power generator;
A separator disposed on a surface opposite to a surface on which the power generation body of the gas flow path forming member is disposed;
With
The gas flow path forming member is:
A first member;
A second member disposed on the power generation body side and having a higher hydrophilicity than the first member;
It is characterized by providing.

  According to the fuel cell of Application Example 1, since the gas flow path forming member includes the second member having high hydrophilicity on the power generation body side, water present in the power generation body is attracted to the second member. Less water moves in the flow path forming member toward the separator side. Therefore, it becomes difficult for water to be discharged by the reaction gas flowing in the gas flow path forming member. Therefore, drying of the electrolyte membrane is suppressed, and a decrease in power generation efficiency can be suppressed.

[Application Example 2] The fuel cell according to Application Example 1,
The fuel cell according to claim 1, wherein the second member is disposed upstream of a flow of gas flowing through the gas flow path forming member.

  In general, in the plane of the electrolyte membrane, the upstream side of the gas flow is easier to dry than the downstream side, but in this way, drying of the electrolyte membrane on the upstream side of the gas flow can be suppressed. . Therefore, a decrease in power generation efficiency can be suppressed.

[Application Example 3] The fuel cell according to Application Example 2,
The gas flow path forming member is:
A third member disposed on the separator side and having a higher hydrophilicity than the first member;
The fuel cell according to claim 1, wherein the third member is disposed on a downstream side of a flow of gas flowing through the gas flow path forming member.

  In the fuel cell of Application Example 3, the gas flow path forming member includes the second member having high hydrophilicity in the upstream region of the gas flow on the power generator side, and has high hydrophilicity on the downstream side of the gas flow on the separator side. A third member is provided. When the gas flow path forming member includes the third member having high hydrophilicity on the separator side, the water present in the power generation body is attracted to the third member and moves toward the separator. Then, when the water moves through the gas flow path forming member, the water is discharged by the reaction gas flowing through the gas flow path forming member. Therefore, in the downstream area of the gas flow, drainage is improved and flooding can be suppressed. Therefore, as described above, drying of the electrolyte membrane can be suppressed in the upstream region of the gas flow, and flooding can be suppressed in the downstream region of the gas flow. Can be suppressed.

[Application Example 4] In the fuel cell according to Application Example 2 or 3,
The fuel is characterized in that the second member and the third member are disposed so as to partially overlap each other when viewed from a direction perpendicular to the laminated surface of the gas flow path forming member. battery.

  In this case, when viewed from the direction perpendicular to the stacking surface of the gas flow path forming member, the portion where the second member and the third member are arranged so as to partially overlap each other, The water present in the water is drawn to the second member and further drawn to the third member. Therefore, the water present in the power generation body is easily moved toward the separator, and the drainage is improved.

[Application Example 5] In the fuel cell according to any one of Application Examples 1 to 4,
The fuel cell according to claim 1, wherein the gas flow path forming member is made of expanded metal.

  The present invention can be realized in various forms. For example, the present invention can be realized in the form of a fuel cell, a fuel cell system including the fuel cell, a moving body equipped with the fuel cell system, and the like. .

A. First embodiment:
A1. Example configuration:
FIG. 1 is a cross-sectional view schematically showing a cross-sectional configuration of a fuel cell 100 as a first embodiment of the present invention. In FIG. 1, the AA cut surface in FIG. 5 mentioned later is shown. The fuel cell 100 is a solid polymer fuel cell that generates power using hydrogen and air.

  As shown in FIG. 1, the fuel cell 100 includes an anode-side porous body 410 and a cathode-side porous body 430 disposed on both sides of a seal member-integrated MEA (Membrane-Electrode Assembly) 200, respectively. The separators 300 are stacked so that the separators 300 are disposed on both sides thereof. In FIG. 1, a part of a portion where a plurality of seal member integrated MEAs 200, an anode-side porous body 410, a cathode-side porous body 430, and a separator 300 are stacked is shown, and the others are not shown. . Hereinafter, the anode side porous body 410 and the cathode side porous body 430 are collectively referred to as porous bodies 410 and 430.

  The anode side porous body 410 and the cathode side porous body 430 in this embodiment correspond to the gas flow path forming member in the claims.

  The fuel cell 100 is formed by laminating a plurality of the above-described components, and as a whole, as shown in FIG. 1, a cathode gas supply manifold 106 for supplying air as cathode gas used for power generation, and cathode exhaust gas. A cathode exhaust gas discharge manifold 108 for discharging. Similarly, an anode gas supply manifold (not shown) for supplying hydrogen as an anode gas used for power generation and an anode exhaust gas discharge manifold (not shown) for discharging anode exhaust gas are provided.

  The air supplied to the fuel cell 100 passes through the cathode gas supply manifold, flows into the cathode side porous body 430 through the cathode gas supply port 336h of the separator 300, and flows through the cathode side porous body 430 while flowing through the MEA 210. To be used for electrode reaction. Cathode exhaust gas containing air that has not been used for the electrode reaction is discharged to the cathode exhaust gas discharge manifold 108 via the cathode exhaust gas discharge port 338h of the separator 300, and is discharged outside the fuel cell 100 through the cathode exhaust gas discharge manifold 108. . Similarly, the hydrogen as the anode gas supplied to the fuel cell 100 is also used for the electrode reaction through the fuel cell 100, and the anode exhaust gas containing hydrogen not used for the electrode reaction is discharged to the outside of the fuel cell 100. Discharged. Further, the separator 300 is formed with a cooling water flow path 110p, and the cooling water flows through the separator, thereby removing heat generated by the electrode reaction of the fuel cell 100 and setting the internal temperature of the fuel cell 100 to a predetermined value. Is kept within the range.

A1-1. Structure of seal member integrated MEA:
FIG. 2 is a plan view showing a planar configuration of the seal member integrated MEA 200. As shown in FIG. 1, the seal member integrated MEA 200 is configured such that a frame-shaped seal member 220 is integrally formed with the MEA 210 on the outer periphery of a MEA 210 whose outer shape is substantially rectangular. 3 is an enlarged cross-sectional view showing an X1 portion in FIG. As shown in FIG. 3, the MEA 210 is formed by laminating the anode 214 and the anode side diffusion layer 216 in this order on one surface of the electrolyte membrane 212 and laminating the cathode 215 and the cathode side diffusion layer 217 in this order on the other surface. The MEA 210 in this embodiment corresponds to the power generator in the claims.

  In the present embodiment, as the electrolyte membrane 212, a polymer electrolyte membrane formed of a fluorine resin is used. As the anode 214 and the cathode 215, an electrode formed from a carbon carrier carrying platinum and a platinum alloy as a catalyst is used. As the anode side diffusion layer 216 and the cathode side diffusion layer 217, carbon felt subjected to water repellent processing is used. For example, water repellent processing can be performed by impregnating carbon felt with a mixed solution obtained by mixing carbon and Teflon (registered trademark). Note that only the contact surface of the anode side diffusion layer 216 in contact with the anode 214 and the contact surface of the cathode side diffusion layer 217 in contact with the cathode 215 may be subjected to water repellent processing, or the anode side diffusion layer 216 and the cathode side The entire diffusion layer 217 may be water-repellent. In this embodiment, the anode-side diffusion layers 216 and 217 are subjected to water repellent processing in order to enhance drainage, but a configuration in which water repellent processing is not performed may be employed.

  The seal member 220 is formed by injection molding using silicone rubber. When molding the seal member 220, silicone rubber is impregnated in the voids inside the anode 214, cathode 215, anode side diffusion layer 216, and cathode side diffusion layer 217, and the sealing member 220 and The MEA 210 is coupled.

  As shown in FIG. 2, the seal member 220 has three cathode gas supply through holes 106s and three cathode exhaust gas discharge through holes 108s, respectively, three anode gas supply through holes 102s and one anode exhaust gas discharge through hole 104s. The cooling water supply through hole 110s and the cooling water discharge through hole 112s are formed one by one. And the seal line SL for preventing the leakage of the reaction gas is formed.

A1-2. Composition of anode side porous body and cathode side porous body:
FIG. 4 is an explanatory diagram showing a schematic configuration of the cathode side porous body 430. 4A is a plan view showing the configuration of the surface of the cathode-side porous body 430 that contacts the cathode-side diffusion layer 217, and FIG. 4B shows the configuration of the surface of the cathode-side porous body 430 that contacts the separator 300. FIG. 4C is an enlarged cross-sectional view showing an AA cut surface in FIG. FIG. 5 is a plan view showing a state where the cathode-side porous body 430 is laminated on the seal member-integrated MEA 200. In FIG. 5, hatching for explaining a region where a second member 432 and a third member 434 described later are disposed is attached to the cathode-side porous body 430. As shown in FIG. 4C, the cathode-side porous body 430 includes a first member 431, a second member 432 having higher hydrophilicity than the first member 431, and the first member 431. A third member 434 having high hydrophilicity. As shown in FIGS. 4 and 5, the outer shape is a substantially rectangular shape that is substantially coincident with the inner frame of the seal member 220 of the seal member integrated MEA 200. In this embodiment, an expanded metal is used as the cathode side porous body 430.

  As shown in FIG. 4A, the cathode-side porous body 430 includes a second member 432 on a part of the surface in contact with the cathode-side diffusion layer 217. As shown in FIG. 4B, the cathode-side porous body 430 includes a third member 434 at a part of the surface in contact with the separator 300. Hereinafter, the second member 432 and the third member 434 are collectively referred to as members 432 and 434.

  As shown in FIG. 4 (a), the second member 432 has a planar area from the upstream of the flow of air as the anode gas (in the figure, the air flow is indicated by an arrow), that is, These are arranged in the region (region A + region B) shown in FIG. On the other hand, the third member 434 is arranged in a region downstream from the midstream of the air flow, that is, a region (region B + region C) shown in FIG. As described above, the second member 432 is disposed on the surface in contact with the cathode-side diffusion layer 217, and the third member 434 is disposed on the surface in contact with the separator 300. FIG. As shown in FIG. 5, the region B includes a first member 431, a second member 432, and a third member 434. In FIG. 5, a region A including the first member 431 and the second member 432, and a region C including the first member 431 and the third member 434 are hatched. A region B including the first member 431, the second member 432, and the third member 434 is shown with cross-hatching.

  In this embodiment, the surface of the expanded metal is roughened by sandblasting to improve the hydrophilicity, thereby forming the second member 432 and the third member 434, and the portion not subjected to the treatment for improving the hydrophilicity. Is the first member 431. In addition, the second member 432 and the third member 434 can be formed by a known method such as imparting hydrophilicity by applying titanium oxide or a hydrophilic paint. Further, the first member 431, the second member 432, and the third member 434 are formed as separate members, respectively, and arranged as shown in FIG. Also good.

  As shown in FIG. 3, the anode-side porous body 410 is configured to be symmetrical with the cathode-side porous body 430 with the MEA 210 interposed therebetween. That is, the anode-side porous body 410 includes a first member 411, a second member 412 having a higher hydrophilicity than the first member 411, and a third member 411 having a higher hydrophilicity than the first member 411. A member 414. In the anode-side porous body 410, the second member 412 is disposed on the anode-side diffusion layer 216 side, and the third member 414 is disposed on the separator 300 side. Similarly to the second member 432 of the cathode-side porous body 430, the second member 412 is disposed on the upstream side of the hydrogen flow, and the third member 414 includes the third member 414 of the cathode-side porous body 430. Similar to member 434, it is located downstream of the hydrogen flow.

  In this embodiment, the first member 411 and the first member 431 are the first member in the claims, the second member 432 and the second member 412 are the second members in the claims, and the third member is the third member. The member 434 and the third member 414 correspond to the third member in the claims. Further, the surface in contact with the separator 300 of the cathode-side porous body 430 or the surface in contact with the cathode-side diffusion layer 217 corresponds to the laminated surface in the claims.

A1-3. Separator configuration:
As shown in FIG. 3, the separator 300 is narrow in the cathode facing plate 330 that contacts the cathode side porous body 430, the anode facing plate 310 that contacts the anode side porous body 410, and the cathode facing plate 330 and the anode facing plate 310. It has a three-layer structure in which the held intermediate plate 320 is laminated.

  Three plates (an anode facing plate 310, a cathode facing plate 330, and an intermediate plate 320) constituting the separator 300 are thin plates made of stainless steel having a substantially rectangular shape, and are manufactured by metal bonding or resin bonding. Instead of stainless steel, other metals such as titanium and aluminum may be used. Since each of these plates is exposed to cooling water as will be described later, it is preferable to use a metal having high corrosion resistance.

  FIG. 6 is a plan view schematically showing a planar configuration of the anode facing plate 310. As shown in the drawing, the anode gas supply through hole 102, the anode exhaust gas discharge through hole 104, the cathode gas supply through hole 106, the cathode exhaust gas discharge through hole 108, An anode gas supply through hole 102a, an anode exhaust gas discharge through hole 104a, a cathode gas supply through hole 106a, a cathode exhaust gas discharge through hole 108a, a cooling water through hole 110a, which constitute the water through holes 110 and 112, 112a is formed.

  A plurality of anode gas supply ports 312h and anode exhaust gas discharge ports 314h are formed along the long sides of the anode facing plate 310 and inside the cathode gas supply through-hole 106a and cathode exhaust gas discharge through-hole 108a. Yes. As shown by the arrows in the figure, hydrogen as anode gas is supplied from the anode gas supply port 312h to the anode-side porous body 410, and anode exhaust gas is discharged from the anode exhaust gas discharge port 314h.

  FIG. 7 is a plan view schematically showing a planar configuration of the intermediate plate 320. As shown in the figure, the intermediate plate 320 has an anode gas supply through hole 102m, an anode exhaust gas discharge through hole 104m, and a cathode gas supply through hole similar to the through holes formed in the anode facing plate 310 described above. 106 m and a cathode exhaust gas discharge through-hole 108 m are formed.

  Further, the anode gas supply connecting portion 102j that connects the anode gas supply through hole 102m and the plurality of anode gas supply ports 312h so that hydrogen flows from the anode gas supply through hole 102m to the plurality of anode gas supply ports 312h. , Is formed. Similarly, an anode exhaust gas discharge connection portion 104j that connects the anode exhaust gas discharge through hole 104m and the plurality of anode exhaust gas discharge ports 314h is formed.

  The cathode gas that connects the cathode gas supply through-hole 106m and the plurality of cathode gas supply ports 336h so that air flows from the three cathode gas supply through-holes 106m to a plurality of cathode gas supply ports 336h described later. A supply connection portion 106j is formed. Similarly, the plurality of cathode exhaust gas discharge ports 248h and the cathode exhaust gas discharge through holes 108m are connected so that the cathode exhaust gas flows from the plurality of cathode exhaust gas discharge ports 248h described later to the three cathode exhaust gas discharge through holes 108m. A cathode exhaust gas discharge connecting portion 108j is formed.

  Further, in order to prevent the temperature of the fuel cell 100 from rising due to power generation, a cooling water flow path 110p is formed in which the cooling water flows through the separator 300 so as to cool the entire MEA 400.

  FIG. 8 is a plan view schematically showing a planar configuration of the cathode facing plate 330. As illustrated, the cathode facing plate 330 has an anode gas supply through hole 102c, an anode exhaust gas discharge through hole 104c, and a cathode gas supply through, similar to the through holes formed in the anode facing plate 310 described above. A hole 106c, a cathode exhaust gas discharge through hole 108c, and cooling water through holes 110c and 112c are formed.

  Further, a plurality of cathode gas supply ports 336 h and cathode exhaust gas discharge ports 248 h are formed inside the cathode gas supply through hole 106 c and the cathode exhaust gas discharge through hole 108 c along the upper and lower sides of the cathode facing plate 330. Yes. As shown by the arrows in the figure, air as cathode gas is supplied from the cathode gas supply port 336h to the cathode side porous body 430, and the cathode exhaust gas is discharged through the cathode exhaust gas discharge port 248h.

  FIG. 9 is a plan view schematically showing a planar configuration of the separator 300. As described above, the separator 300 is formed by joining the anode facing plate 310, the intermediate plate 320, and the cathode facing plate 330. Here, a state seen from the anode facing plate 310 side is shown. As can be seen from the drawing, when the anode facing plate 310, the intermediate plate 320, and the cathode facing plate 330 are stacked, the through holes overlap to form the through holes that penetrate the separator 300.

  Further, by stacking the anode facing plate 310, the intermediate plate 320, and the cathode facing plate 330, as shown in the figure, an anode gas supply through hole 102, an anode gas supply connection portion 102j, and an anode gas supply port 312h are formed. Together, an anode gas (hydrogen) supply path is formed. Similarly, an anode exhaust gas discharge path, a cathode gas (air) supply path, and a cathode exhaust gas discharge path are formed.

A2. Effects of the embodiment:
FIG. 10 is an explanatory diagram for explaining the flow of water on the cathode side. 10, the X2 part in FIG. 3 is shown enlarged. The arrows in the figure indicate the flow of water discharged from the electrolyte membrane 212 and the cathode 215. This water includes water contained in the air in addition to the generated water generated at the cathode 215. As described above, in the region A, the cathode-side porous body 430 includes the second member 432 having higher hydrophilicity than the first member 431 on the surface in contact with the cathode-side diffusion layer 217. Therefore, the water in the cathode 215 and the electrolyte membrane 212 moves toward the cathode-side porous body 430 due to the hydrophilicity of the second member 432 as indicated by arrows in the figure.

  However, in the region A, since the third member 434 is not provided on the separator 300 side, the water is less likely to move toward the separator 300. Then, in the region A, since there is not much water in the first member 431, the air that flows through the cathode-side porous body 430 is difficult to discharge, and the discharge of water is suppressed. Conventionally, when dry air is supplied upstream of the air flow, water tends to be discharged, and the electrolyte membrane 212 may be dried to reduce power generation efficiency. According to the above, since the discharge of water is suppressed upstream of the air flow (corresponding to the region A), it is possible to suppress the drying of the electrolyte membrane 212 and to suppress the decrease in power generation efficiency.

  Conventionally, downstream of the air flow, the air flow rate is slower than that of the upstream, and it is difficult for water to be discharged. Therefore, flooding is likely to occur, and as a result, power generation efficiency is reduced. In the present embodiment, the cathode-side porous body 430 has a third member 434 that is more hydrophilic than the first member 431 on the surface that contacts the separator 300 in the region C corresponding to the downstream of the air flow. Has been. Therefore, the water in the cathode 215 and the electrolyte membrane 212 moves toward the separator 300 due to the hydrophilicity of the third member 434 as indicated by arrows in the figure. Then, when moving in the cathode side porous body 430, it is discharged out of the fuel cell 100 together with the air flowing in the cathode side porous body 430. Therefore, since the drainage is promoted downstream of the air flow (corresponding to the region C), flooding can be suppressed and a decrease in power generation efficiency can be suppressed.

  Further, in the region B, the cathode-side porous body 430 includes a second member 432 on the cathode-side diffusion layer 217 side and a third member 434 on the separator 300 side. In the midstream region (region B) of the air flow, the water content of the MEA 210 tends to be smaller than that in the downstream region. In such a case, when the highly hydrophilic second member 432 is provided also on the cathode side diffusion layer 217 side, water is attracted to the second member 432, and further, from the second member 432. It is attracted to the third member 434. Therefore, drainage is improved, flooding can be suppressed, and reduction in power generation efficiency can be suppressed.

  In addition, also on the anode side, the drainage property is adjusted similarly to the cathode side, and a decrease in power generation efficiency can be suppressed.

  As described above, according to the fuel cell 100 of the present embodiment, the water content of the MEA 210 is adjusted in-plane by adjusting the drainage performance stepwise along the flow of the reaction gas (air, hydrogen). Variations can be reduced and a decrease in power generation efficiency can be suppressed.

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

  (1) In the above embodiment, the cathode-side porous body 430 includes the second member 432 on the surface in contact with the cathode-side diffusion layer 217 and the third member 434 on the surface in contact with the separator 300. The cathode side porous body 430 may not include the third member. Even if it does in this way, the drying of the electrolyte membrane 212 can be suppressed and the fall of electric power generation efficiency can be suppressed.

  (2) In the above embodiment, the second member 432 and the third member 434 are arranged so as to overlap in the region B when viewed from the direction perpendicular to the stacked surface of the cathode-side porous body 430. The arrangement of the second member 432 and the third member 434 is not limited to the above-described embodiment. FIG. 11 is a cross-sectional view schematically showing a cross-sectional configuration of a cathode-side porous body according to a modification. For example, as shown in FIG. 11A, the second member 432 and the third member 434 may be formed adjacent to each other without overlapping. Further, as shown in FIG. 11B, the area A may be made smaller. Thus, the arrangement and size (area) of the second member 432 and the third member 434 may be determined according to, for example, the in-plane distribution of the water content of the MEA 210.

  (3) In the above embodiment, carbon felt is used as the diffusion layers 216 and 217, but carbon paper, carbon cloth, etc. may be used instead of carbon felt. Moreover, although the expanded metal is used as a porous body, you may use the foam metal produced by well-known methods, such as a slurry foaming method and a foam sintering method.

  (4) In the fuel cell 100 of the first embodiment, the anode side porous body 410 and the cathode side porous body 430 are respectively disposed on both surfaces of the MEA 210. However, the present invention is not limited to such a configuration. For example, the cathode-side porous body 430 may be disposed only on the cathode side of the MEA 210, and the conventional porous body may be disposed on the anode side. Even if it does in this way, since the moisture content of MEA210 (electric power generation body) is adjusted, the fall of electric power generation efficiency can be suppressed.

  Further, in the case of a fuel cell having a stack structure, water tends to accumulate near the end in the stacking direction. Therefore, for the cell module near the end in the stacking direction (the sealing member integrated MEA 200 is sandwiched between the separators 300), the porous bodies 410 and 430 similar to the above-described embodiment are used, and the cell module near the center is used. A conventional porous body may be used. Even in this case, it is possible to adjust the drainage performance of the portion where water easily collects, and to suppress the decrease in the power generation efficiency of the entire fuel cell stack.

  (5) In the above embodiment, the MEA 210 is shown in which the diffusion layers 216 and 217 are arranged on both the anode side and the cathode side. However, the MEA 210 may be configured without the diffusion layer. Since water is generated by the electrode reaction on the cathode side, if the diffusion layer 217 is present, the generated water is easily sucked and discharged, but such necessity is low because water is not generated on the anode side. Therefore, for example, a configuration in which no diffusion layer is disposed on the anode side may be employed. Furthermore, a configuration in which a diffusion layer is not disposed on the cathode side may also be employed.

1 is a cross-sectional view schematically showing a cross-sectional configuration of a fuel cell 100 as a first embodiment of the present invention. It is a top view which shows the planar structure of seal member integrated MEA200. It is an expanded sectional view which expands and shows the X1 part in FIG. FIG. 4 is an explanatory diagram showing a schematic configuration of a cathode-side porous body 430. 4 is a plan view showing a state where a cathode-side porous body 430 is laminated on a seal member-integrated MEA 200. FIG. 2 is a plan view schematically showing a planar configuration of an anode facing plate 310. FIG. 3 is a plan view schematically showing a planar configuration of an intermediate plate 320. FIG. 3 is a plan view schematically showing a planar configuration of a cathode facing plate 330. FIG. 3 is a plan view schematically showing a planar configuration of a separator 300. FIG. It is explanatory drawing for demonstrating the flow of the water by the side of a cathode. It is sectional drawing which shows roughly the cross-sectional structure of the cathode side porous body of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Fuel cell 102a, 102c, 102m, 102s ... Through-hole for anode gas supply 102j ... Connection part for anode gas supply 104a, 104c, 104m, 104s ... Through-hole for anode exhaust gas discharge 104j ... Connection part for anode exhaust gas discharge 106 ... Cathode gas supply manifold 106a, 106c, 106m, 106s ... Cathode gas supply through hole 106j ... Cathode gas supply connection 108 ... Cathode exhaust gas discharge manifold 108a, 108c, 108m, 108s ... Cathode exhaust gas discharge through hole 108j ... Cathode exhaust gas Discharge connections 110a, 110c ... cooling water through holes 110p ... cooling water flow passages 110s ... cooling water supply through holes 112s ... cooling water discharge through holes 200 ... sealing member integrated MEA
210 ... MEA
212 ... Electrolyte membrane 214 ... Anode 215 ... Cathode 216 ... Anode side diffusion layer 217 ... Cathode side diffusion layer 220 ... Sealing member 300 ... Separator 310 ... Anode facing plate 320 ... Intermediate plate 330 ... Cathode facing plate 312h ... Anode gas supply port 314h ... Anode exhaust gas outlet 336h ... Cathode gas supply port 338h ... Cathode exhaust outlet 400 ... MEA
410: Anode-side porous body 411, 431 ... First member 412, 432 ... Second member 414, 434 ... Third member 430 ... Cathode-side porous body SL ... Seal line

Claims (5)

A fuel cell,
A power generator in which electrodes are arranged on both sides of the electrolyte membrane;
A gas flow path forming member made of a porous material, disposed on at least one surface of the power generator;
A separator disposed on a surface opposite to a surface on which the power generation body of the gas flow path forming member is disposed;
With
The gas flow path forming member is:
A first member;
A second member disposed on the power generation body side and having a higher hydrophilicity than the first member;
It is characterized by providing. The fuel cell according to claim 1,
The fuel cell according to claim 1, wherein the second member is disposed upstream of a flow of gas flowing through the gas flow path forming member. The fuel cell according to claim 2, wherein
The gas flow path forming member is:
A third member disposed on the separator side and having a higher hydrophilicity than the first member;
The fuel cell according to claim 1, wherein the third member is disposed on a downstream side of a flow of gas flowing through the gas flow path forming member. The fuel cell according to claim 2 or 3,
The fuel is characterized in that the second member and the third member are disposed so as to partially overlap each other when viewed from a direction perpendicular to the laminated surface of the gas flow path forming member. battery. The fuel cell according to any one of claims 1 to 4, wherein
The fuel cell according to claim 1, wherein the gas flow path forming member is made of expanded metal.

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