JP2002151104A - Gas passage plate for fuel cell and fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas passage plate for a fuel cell capable of enhancing the exhaust of condensed water inside a gas passage and to provide the fuel cell. SOLUTION: A conductive square cathode side separator 10 for the fuel cell is used. Two sets of U-shaped gas passages (gas passages 211, 212) are installed on the surface of the gas passage over from a gas passage inlet CIN for supplying reaction gas to a gas passage outlet COUT for exhausting the reaction gas through approaching passages 211A, 212A, communication passages 201, 202, and return passages 211B, 212B, and these two sets of passages are arranged so as to overlap the return passages 211B, 212B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas passage plate for a fuel cell and a fuel cell, and more particularly to a gas passage plate and a fuel cell for a fuel cell which can improve the drainage of dew condensation water. It relates to a battery.

[0002]

2. Description of the Related Art For example, an electrolyte / electrode structure in which an anode electrode and a cathode electrode are opposed to each other with a solid polymer electrolyte membrane sandwiched therebetween is defined as one unit.
A solid polymer electrolyte type fuel cell constituted by laminating a plurality of these has been developed and is being put to practical use for various uses. In this type of fuel cell, the fuel gas, for example, hydrogen gas, supplied to the anode electrode side is hydrogen-ionized on the catalyst electrode, and moves to the cathode electrode via a moderately humidified solid polymer electrolyte membrane. . The electrons generated during that time are taken out to an external circuit and used as DC electric energy. Since an oxidant gas, for example, oxygen gas or air is supplied to the cathode electrode, the hydrogen ions, the electrons, and the oxygen gas react at the cathode electrode to generate water.

[0003] When a fuel gas and an oxidizing gas are supplied to the anode electrode and the cathode electrode, an electrolyte / electrode structure and both sides thereof are provided so that the supplied gas can be efficiently used for the reaction. A seal member is interposed between the opposed separator to ensure airtightness, and a gas flow path for guiding fuel gas and oxidant gas is provided on a portion of the separator surface surrounded by the seal member. (Patent 27
No. 11018).

This will be described with reference to FIG. In the figure, 1 is a separator (for example, an anode-side separator)
Is shown. A recess 2 is formed at the center of the separator 1, and a meandering groove 3 is formed therein. Separator 1
Gas supply openings 4 on the upper left and lower right sides of the recess 2
And a discharge opening 5 are formed, and the supply opening 4 and the discharge opening 5 for the reaction gas communicate with the meandering groove 3 via a fluid inlet 6 and a fluid outlet 7, respectively. Therefore, the reaction gas supplied from the supply opening 4 is supplied from the fluid inlet 6 to the meandering groove 3 and is efficiently subjected to the reaction, and the reacted gas is discharged from the fluid outlet 7 to the discharge opening 5.

[0005]

However, in the above-mentioned prior art, when the water contained in the reaction gas or the condensed water condensed by the water generated by the reaction closes the meandering groove 3, the condensed water is easily discharged to the outside. However, as a result, there is a problem that the reaction becomes non-uniform in a portion where the reaction gas is difficult to flow. Further, in a low load region, the flow rate of the reaction gas is relatively reduced, so that the drainage of the condensed water is deteriorated. Therefore, if more reaction gas is flowed than necessary in order to maintain the drainage of the condensed water, there is a problem that the utilization rate of the reaction gas decreases and the system efficiency deteriorates. Therefore, the present invention
An object of the present invention is to provide a gas flow channel plate and a fuel cell for a fuel cell, which can improve the discharge performance of dew condensation water in a gas flow channel and increase the gas utilization rate even in a low load region.

[0006]

In order to solve the above-mentioned problems, the invention of a gas flow plate for a fuel cell according to the present invention is directed to a square gas flow plate having conductivity for a fuel cell. (For example, the cathode-side separator 1 in the embodiment
0, the anode-side separator 11) on the gas flow path surface, from a gas flow path inlet (for example, the gas flow path inlets CIN, AIN in the embodiment) for supplying the reaction gas, to the outward path (for example, the outward path in the embodiment). 211A, 212A,
Outgoing paths 291A, 292A), turn-back portions (for example, connecting paths 201 and 202, connecting paths 281, 281 in the embodiment)
82), return path (for example, return path 211 in the embodiment)
B, 212B, return paths 291B, 292B), and a U-shaped gas flow path (for example, gas in the embodiment) to a gas flow path outlet (for example, the gas flow path exit COUT, AOUT in the embodiment) for discharging the reaction gas. Channels 211 and 21
2, gas flow passages 291 and 292) are provided, and these two gas flow passages are arranged such that the return path portion is overlapped. With such a configuration, the flow velocity of the reaction gas in the overlapped return path increases, and thereby, it is possible to effectively discharge the dew water generated in the gas flow path,
A gas flow path without clogging can be secured.

According to the invention of a fuel cell according to a second aspect, an electrolyte-electrode structure in which an electrolyte is sandwiched between an anode electrode and a cathode electrode (for example, the electrolyte-electrode structure 7 in the embodiment) is sandwiched between a pair of separators. A fuel cell, wherein a reaction gas is discharged from a gas flow path inlet for supplying a reaction gas to a rectangular gas flow path surface facing an anode electrode or a cathode electrode of the separator, through a forward path, a folded portion, and a return path. And two sets of U-shaped gas flow paths leading to the gas flow path outlets are provided, and the two sets of gas flow paths are arranged on the surface of the gas flow path with the return path overlapped. With this configuration, even when dew condensation water accumulates in the gas flow path of the separator during operation of the fuel cell, the flow velocity of the reaction gas in the overlapped return path increases, whereby the gas flow path Since the dew water generated in the separator can be effectively discharged, a uniform reaction on the gas flow path surface of the separator can be ensured. In addition, the apparent electrode density can be appropriately adjusted because the reaction gas flow area in the electrode can be changed by selectively using two sets of U-shaped gas flow paths and one set of gas flow paths according to the load. System efficiency. In the low-load region, one set of gas flow paths can be used. Therefore, as in the case of using two gas flow paths at low load, more than necessary to maintain the drainage of dew condensation water. Since there is no need to flow the reaction gas, the utilization rate of the reaction gas is increased, and in that respect, the system efficiency can be increased.

According to a third aspect of the present invention, in the fuel cell invention according to the second aspect, a gas flow path inlet and an outlet of the separator on the anode electrode side are provided on one side,
The gas flow path inlet and outlet of the separator on the cathode electrode side are provided on the other side. With this configuration, in particular, the condensed water in the folded portion of the separator on the cathode electrode side where dew water easily accumulates penetrates the electrolyte and reversely diffuses and moves to the gas flow path inlet side of the separator on the anode electrode side, Since the humidification of the reaction gas on the anode electrode side is promoted, the size of the humidification device can be reduced accordingly. Further, since the portion where the return path of the separator on the cathode electrode side with a large amount of water is overlapped with the part where the return path of the separator on the anode electrode side is overlapped, the return path on the anode side where the water content is low is sufficiently reduced by reverse diffusion. Can be humidified.

According to a fourth aspect of the present invention, in the fuel cell device according to the second or third aspect, the folded portion is formed as a buffer portion. With this configuration, even if a part of the gas flow path is clogged with dew condensation water, via the buffer unit,
Since the reaction gas can be guided to another flow path which is not clogged by the dew condensation water, it is possible to prevent the gas flow path from being completely clogged and to eliminate the non-uniformity of the reaction.
In addition, since the folded portion where the dew condensation water relatively easily accumulates is arranged at a position close to the gas flow path inlet, the gas flow path inlet that needs the most humidification can be effectively humidified.

According to a fifth aspect of the present invention, in the fuel cell invention according to any one of the second to fourth aspects, the gas flow path includes a plurality of flow paths (for example, the grooves 18 and 18 in the embodiment). 26). With this configuration, even if one gas flow path is clogged, the reaction gas can be supplied through another gas flow path, so that the reliability is higher than in the case of a single gas flow path. Sex is enhanced.

According to a sixth aspect of the present invention, in the fuel cell invention according to any one of the second to sixth aspects, the total sum of the cross-sectional areas of the two forward paths is larger than the total sum of the cross-sectional areas of the return paths. It is characterized by the following. With this configuration, it is possible to reliably increase the flow velocity of the reaction gas in the return path with respect to the outward path, and to improve the drainage of the condensed water.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 9 show a first embodiment of the present invention. FIG. 1 shows a cathode-side separator (gas flow plate) 10 which is press-formed from a metal material such as stainless steel. The cathode-side separator 10 constitutes a fuel cell by sandwiching an electrolyte / electrode structure together with an anode-side separator (gas flow plate) 11, which will be described later. Of the fuel cell stack. The cathode-side separator 10 includes:
Three communication holes 12Ca, 13C, 12Cb on the left side
Have three communication holes 14Ca, 15C, and 14C on the right side.
b are each formed. One communication hole 16, 17 is formed in each of the upper side portion and the lower side portion. That is, this embodiment is a so-called internal manifold type.

Specifically, oxidant gas (for example, air) inlet communication holes 12Ca and 12Cb are formed on the upper and lower sides of the left side of the cathode separator 10, and in the center of the left side. An outlet side communication hole 13C for the oxidizing gas is formed. On the other hand, fuel gas (for example, hydrogen) inlet communication holes 14Ca, 14Cb are formed on the upper and lower sides of the right side of the cathode separator 10, and the outlet communication of the fuel gas is formed in the center of the right side. A hole 15C is formed.

An outlet side communication hole 16 for the coolant (for example, ethylene glycol) is formed on the upper side of the cathode side separator 10, and an inlet side communication hole 17 for the coolant is formed on the lower side. And each communication hole 12C of the oxidant gas
a, 12Cb, 13C and each communication hole 14C for fuel gas
a, 14Cb, 15C and the respective coolant communication holes 17, 16
Is formed as a rectangular gas flow path surface facing the cathode electrode and supplied with the oxidizing gas.

A plurality of grooves (flow paths) 18 extending linearly in the lateral direction are formed on the gas flow path surface (four, five, four from the top).
This is provided as a set by press molding.
The groove 18 is a concave portion of the corrugated portion, and is formed as a ridge 19 on the back side of the cathode-side separator 10 shown in FIG. The left end of each groove 18 is connected to each of the communication holes 12Ca, 12Cb, 13C of the oxidizing gas.
Are arranged at a predetermined interval from the right edge of the
8 are connected to the fuel gas communication holes 14Ca, 14Ca.
Cb, 15C are arranged at a predetermined interval from the left edge position.

In FIG. 1, a fuel gas inlet side communication hole 1 is shown.
4Ca, 14Cb, the outlet communication hole 15C, and the coolant inlet communication hole 17 and the outlet communication hole 16 are each surrounded by a seal member CS. The oxidant gas inlet-side communication holes 12Ca and 12Cb and the outlet-side communication hole 13C are formed by sealing members other than the right edge with a sealing member CS.
Surrounded by That is, the inlet-side communication holes 12Ca, 12Cb and the outlet-side communication hole 13C for the oxidizing gas communicate with the gas flow path surface at the right edge, respectively.

A seal member CS is provided between the inlet-side communication hole 12Ca and the outlet-side communication hole 13C for the oxidizing gas, and the seal member CS extends seamlessly between the grooves 18 on the gas flow path surface. , And an extension CS1 reaching near the right end of the groove 18. Further, a seal member CS is provided between the inlet-side communication hole 12Cb and the outlet-side communication hole 13C of the oxidizing gas, and the seal member CS extends seamlessly between the grooves 18 on the gas flow path surface, An extension CS2 is provided near the right end of the groove 18. The seal member CS and the extension portions CS1 and CS2 are attached by injection, baking, bonding, or the like. Here, between the grooves 18 in which the extending portions CS1 and CS2 are provided means between each pair of the grooves 18 formed as a group as described above, and this portion is a flat surface which is not subjected to press molding. Surface H.

Here, the right end of the extension CS1
An interval for forming the communication path 201 is secured between the seal member CS and a seal member CS disposed at a position facing the seal member CS. A communication path 202 is provided between the right end of the extension CS2 and the seal member CS disposed at a position facing the end.
Are formed at intervals. In addition, these connecting channels 2
01 and 202 function as a buffer unit for collecting the reaction gas on the upstream side. In addition, the inlet side communication hole 12Ca
The end of the groove 18 on the side of the side is formed as a gas flow path inlet CIN, and the end of the groove 18 on the side of the outlet side communication hole 13C is formed as a gas flow path outlet COUT.
The IN and the gas channel outlet COUT also function as a buffer section.

As a result, a U-shaped gas (oxidizing gas) flow path 211 having the extension CS1 as a boundary and the connecting path 201 turned back is provided on the gas flow path surface of the cathode-side separator 10. A U-shaped gas flow path 212 having the extension CS2 as a boundary portion and the communication path 202 as a folded portion.
Are formed.

That is, the U-shaped gas flow path 211 has an outward path 211A from the gas flow path inlet CIN on the inlet side communication hole 12Ca side to the communication path 201 which is a folded portion, and a communication path from the communication path 201 to the outlet side communication path. The U-shaped gas flow path 212 is formed from the gas flow path inlet CIN on the inlet side communication hole 12Cb side to the connecting path 202 which is a folded portion. Outgoing path 212A, the communication path 202 and the outlet side communication hole 1
And a return path 212B to the gas flow path exit COUT on the 3C side. Therefore, the gas flow path 211 and the gas flow path 212
A set of gas flow paths is provided, and the return paths 211B and 212B of the gas flow paths 211 and 212 are arranged so as to overlap each other.

On the other hand, FIG. 2 shows the cathode side separator 10 of FIG. 1 viewed from the back side. Therefore,
The right side in FIG. 2 corresponds to the left side in FIG. 1, and the left side in FIG. 2 corresponds to the right side in FIG. More specifically, the oxidant gas inlet-side communication holes 12Ca, 1
2Cb is formed, and an outlet side communication hole 13C for the oxidizing gas is formed in the center of the right side. Further, the fuel gas inlet side communication holes 14Ca, 1
4Cb is formed, and a fuel gas outlet communication hole 15C is formed in the center of the left side.

The upper side of the cathode-side separator 10 is provided with a coolant outlet-side communication hole 16 as in FIG. 1, and the lower side is provided with a coolant inlet-side communication hole 17 as shown in FIG.
Each of the oxidant gas communication holes 12Ca, 12Cb, 1
3C and the communication holes 14Ca, 14Cb, 15 of the fuel gas.
A portion surrounded by C and the communication holes 17 and 16 for the coolant is configured as a cooling surface to which the coolant is supplied.

A protrusion 19 is formed on the cooling surface at a position corresponding to the groove 18 described with reference to FIG. Therefore, like the groove 18,
It is formed as a set of several pieces (four, five, four from the top). Here, the ridge 19 is a convex portion of the portion formed in a corrugated plate shape. Therefore, the groove 22 is formed between the adjacent protrusions 19. The right end of each ridge 19 is connected to each of the communication holes 12Ca, 12C for the oxidizing gas.
b, 13C are arranged at a predetermined interval from the left edge position, and the left end of each ridge 19 is connected to each communication hole 1 of the fuel gas.
4Ca, 14Cb, and 15C are arranged at a predetermined interval from the right side edge position.

In FIG. 2, the oxidant gas inlet communication holes 12Ca, 12Cb, the outlet communication hole 13C, the fuel gas inlet communication holes 14Ca, 14Cb, and the outlet communication hole 15C.
Are surrounded by seal members RS. Further, the periphery of the coolant communication side communication hole 16 is surrounded by a seal member RS except for a part (left side in FIG. 2) on the cooling surface side which is cut off as a cutout K1. Further, the periphery of the coolant inlet side communication hole 17 is surrounded by a seal member RS except for a part cut off on the cooling surface side (the right side in FIG. 2) as a cutout K2. That is,
The coolant inlet side communication hole 17 communicates with the cooling surface at the notch K2, and the outlet side communication hole 16 communicates with the notch K.
1 communicates with the cooling surface.

A seal member RS is provided between the fuel gas inlet side communication hole 14Ca and the outlet side communication hole 15C, and the seal member RS is seamlessly provided with a rib 19 on the cooling surface.
Extending part R extending to the vicinity of the right end of the ridge 19
S1 is provided. In addition, the oxidant gas inlet side communication hole 1
A sealing member RS is provided between 2Cb and the outlet side communication hole 13C.
The sealing member RS extends seamlessly between the projections 19 on the cooling surface, and has an extension RS2 reaching near the left end of the projections 19. The seal member RS and the extension portions RS1 and RS2 are attached by injection, baking, bonding, or the like. Here, between the ridges 19 provided with the extending portions RS1 and RS2 means between each pair of the ridges 19 formed as a group as described above, and this portion is subjected to press molding. There is no flat surface H.

Here, the right end of the extension RS1
An interval for forming a communication path 241 is secured between the seal member RS and a seal member RS disposed at a position facing the seal member RS. A communication path 242 is provided between the left end of the extension RS2 and the seal member RS disposed at a position facing the left end.
Are formed at intervals. As a result, on the cooling surface of the cathode-side separator 10, the two communication paths 242, 24 are formed with the extension part RS2 and the extension part RS1 as boundary parts.
A meandering coolant flow path 25 having a folded portion 1 is formed.

FIG. 3 shows the anode-side separator 1.
1, and press-formed from a metal material such as stainless steel in the same manner as the cathode-side separator 10 shown in FIG.
The electrolyte / electrode structure is sandwiched at a position facing the cathode-side separator 10. The anode-side separator 11 has three communication holes 12 </ b> Aa, 13 </ b> A in the right side thereof facing the left side of the cathode side separator 10.
A, 12Ab are also provided with three communication holes 14Aa, 1A on the left side thereof opposed to the right side of the cathode separator 10.
5A and 14Ab are formed. Also, one communication hole 16, 17 is formed in each of the upper side portion and the lower side portion. It is an internal manifold type like the cathode side separator 10 of FIG.

Specifically, the upper side and lower side of the right side of the anode side separator 11 are provided with the oxidant gas inlet side communication holes 12.
Aa and 12Ab are formed, and an outlet side communication hole 13A for the oxidizing gas is formed in the center of the right side. on the other hand,
Fuel gas inlet communication holes 14Aa, 14Ab are formed on the upper and lower sides of the left side of the anode separator 11, and a fuel gas outlet communication hole 15 is formed in the center of the left side.
A is formed.

A coolant outlet-side communication hole 16 is formed in the upper side of the anode-side separator 11, and a coolant inlet-side communication hole 17 is formed in the lower side. A portion surrounded by the communication holes 12Aa, 12Ab, 13A for the oxidizing gas, the communication holes 14Aa, 14Ab, 15A for the fuel gas, and the communication holes 17, 16 for the coolant faces the anode electrode. It is configured as a rectangular gas flow path surface to which fuel gas is supplied.

The cathode separator 1 is provided on the surface of the gas passage.
Corresponding to 0, a plurality of grooves (flow paths) 26 extending linearly in the horizontal direction are provided in groups of several (four, five, four from the top) by press molding. Here the groove 26
Is a concave portion of a portion formed in a corrugated plate shape, and is formed as a ridge 27 on the back side of the anode-side separator 11 shown in FIG. The right end of each groove 26 is arranged at a predetermined distance from the left edge position of each of the oxidant gas communication holes 12Aa, 12Ab, 13A, and the left end of each groove 26 is a fuel gas. Communication holes 14Aa, 14Ab, 15A
Are arranged at a predetermined interval from the position of the right edge.

In FIG. 3, seal members AS surround the oxidant gas inlet-side communication holes 12Aa and 12Ab, the outlet-side communication hole 13A, and the coolant inlet-side communication hole 17 and the outlet-side communication hole 16, respectively. It is surrounded. In addition, the fuel gas inlet communication holes 14Aa, 14Ab and the outlet communication hole 15A are formed by sealing members AS other than the right edge.
Surrounded by That is, the fuel gas inlet side communication hole 1
The 4Aa, 14Ab, and the outlet-side communication hole 15A communicate with the gas flow path surface at the right edge.

A seal member AS is provided between the fuel gas inlet side communication hole 14Aa and the outlet side communication hole 15A, and the seal member AS extends seamlessly between the grooves 26 on the gas flow path surface. An extension AS1 is provided near the right end of the groove 26. A seal member AS is provided between the fuel gas inlet side communication hole 14Ab and the outlet side communication hole 15A, and the seal member AS extends seamlessly between the grooves 26 on the gas flow path surface. 26 is provided with an extension part AS2 reaching near the right end. Note that the sealing member AS and the extending portions AS1 and AS2 are injection-molded.
It is attached by baking, bonding, etc. here,
The space between the grooves 26 provided with the extending portions AS1 and AS2 means the space between each pair of the grooves 26 formed as a group as described above, and this portion is a flat surface H which is not subjected to press molding.
It has become.

Here, the right end of the extension portion AS1 is
An interval for forming the communication path 281 is ensured between the seal member AS and the seal member AS disposed at a position facing this. A communication path 282 is provided between the right end of the extension portion AS2 and the sealing member AS disposed at a position facing the right end.
Are formed at intervals. In addition, these connecting channels 2
The reference numerals 81 and 282 function as buffer units for collecting the reaction gas on the upstream side. In addition, the inlet side communication hole 14Aa
The end of the groove 26 on the side of the side is configured as a gas flow path inlet AIN, and the end of the groove 26 on the side of the outlet side communication hole 15A is configured as a gas flow path outlet AOUT.
The IN and the gas flow path outlet AOUT also function as a buffer section.

As a result, a U-shaped gas (fuel gas) passage 291 having the extension portion AS1 as a boundary portion and the connecting passage 281 as a folded portion is provided on the gas passage surface of the anode-side separator 11. A U-shaped gas flow path 292 having the extension portion AS2 as a boundary portion and the communication path 282 as a folded portion.
Are formed.

That is, the U-shaped gas flow path 291 has an outward path 291A from the gas flow path entrance AIN on the inlet side communication hole 14Aa side to the communication path 281 which is a turn-back portion, and a communication path from the communication path 281 to the outlet side communication path. The U-shaped gas flow path 292 extends from the gas flow path inlet AIN on the inlet side communication hole 12Ab side to the connection path 282 which is a folded portion. The outgoing path 292A, the communication path 282 and the exit side communication hole 1
And a return path 292B to the gas flow path outlet AOUT on the 5A side. Therefore, the gas flow path 291 and the gas flow path 292 are provided on the gas flow path surface of the anode-side separator 11.
A set of gas flow paths is provided, and the return paths 291B and 292B of the gas flow paths 291 and 292 are arranged so as to overlap each other.

On the other hand, FIG. 4 shows the anode-side separator 11 of FIG. 3 viewed from the back side. Therefore,
The right side in FIG. 4 corresponds to the left side in FIG. 3, and the left side in FIG. 4 corresponds to the right side in FIG. Specifically, on the upper and lower sides of the left side portion, the oxidant gas inlet-side communication holes 12Aa, 1
2Ab is formed, and an outlet side communication hole 13A for the oxidizing gas is formed in the center of the left side. In addition, the fuel gas inlet side communication holes 14Aa, 1
4Ab is formed, and a fuel gas outlet communication hole 15A is formed in the center of the right side. 3, an outlet communication hole 16 for the coolant is formed on the upper side of the anode-side separator 11, and an inlet communication hole 17 for the coolant is formed on the lower side. Each of the communication holes 12Aa, 12Ab, and 13A of the oxidant gas and each of the communication holes 1A
4Aa, 14Ab, 15A, and each communication hole 17,
The portion surrounded by 16 is configured as a cooling surface to which the cooling liquid is supplied.

A protrusion 27 is formed on the cooling surface at a position corresponding to the groove 26 described with reference to FIG. Therefore, like the groove 26,
It is formed as a set of several pieces (four, five, four from the top). Here, the protruding ridge 27 is a convex portion of the portion formed in a corrugated plate shape. Therefore, the groove 30 is formed between the adjacent ridges 27. The left end of each ridge 27 is connected to each of the communication holes 12Aa, 12A of the oxidizing gas.
b, 13A are arranged at a predetermined interval from the right edge position, and the right end of each ridge 27 is connected to each communication hole 1 of the fuel gas.
4Aa, 14Ab, and 15A are arranged at predetermined intervals from the left edge position.

In FIG. 4, the oxidizing gas inlet communication holes 12Aa, 12Ab, the outlet communication hole 13A, the fuel gas inlet communication holes 14Aa, 14Ab, and the outlet communication hole 15A.
Are surrounded by seal members RS. In addition, the periphery of the coolant communication side communication hole 16 is surrounded by a sealing member RS except for a part (the right side in FIG. 4) on the cooling surface side, which is cut off as a cutout K1. Further, the periphery of the coolant inlet side communication hole 17 is surrounded by a seal member RS except for a part (left side in FIG. 4) on the cooling surface side which is cut off as a cutout K2. That is,
The coolant inlet side communication hole 17 communicates with the cooling surface at the notch K2, and the outlet side communication hole 16 communicates with the notch K.
1 communicates with the cooling surface.

A seal member RS is provided between the fuel gas inlet side communication hole 14Aa and the outlet side communication hole 15A, and the seal member RS is seamlessly provided with a projection 27 on the cooling surface.
Extending part R extending to the vicinity of the left end of the ridge 27
S1 is provided. In addition, the oxidant gas inlet side communication hole 1
A sealing member RS is provided between 2Ab and the outlet side communication hole 13A.
The sealing member RS extends seamlessly between the ridges 27 on the cooling surface, and has an extension portion RS2 reaching near the right end of the ridge 27. The seal member RS and the extension portions RS1 and RS2 are attached by injection, baking, bonding, or the like. Here, "between the ridges 27 provided with the extending portions RS1 and RS2" means between each pair of the ridges 27 formed as a group as described above, and this portion is subjected to press molding. There is no flat surface H.

Here, the left end of the extension RS1
An interval for forming a communication path 311 is secured between the seal member RS and a seal member RS disposed at a position facing the seal member RS. A communication path 312 is provided between the right end of the extension RS2 and the seal member RS disposed at a position facing the right end.
Are formed at intervals. As a result, the cooling surface of the anode-side separator 11 has two connecting paths 312 and 31 with the extending part RS2 and the extending part RS1 as boundary parts.
A meandering coolant flow path 25 having a folded portion 1 is formed.

FIGS. 5 to 9 show cross sections of the fuel cell 8 constituted by sandwiching the electrolyte / electrode structure 7 between the cathode-side separator 10 and the anode-side separator 11 in each part of FIG. is there. FIG. 5 is a sectional view taken along the line AA in FIG.
It is sectional drawing which follows a line. In the figure, an electrolyte / electrode structure 7 is constituted by a solid polymer electrolyte membrane and an anode electrode and a cathode electrode provided on both sides of the solid polymer electrolyte membrane. 7 is sandwiched between a cathode-side separator 10 and an anode-side separator 11 via seal members CS and AS.

At this time, the cathode separator 10 shown in FIG.
The oxidant gas inlet-side communication holes 12Ca and 12Cb and the outlet-side communication hole 13C of FIG.
Of the oxidizing gas inlet side communication holes 12Aa and 12Ab and the outlet side communication hole 13A. In addition, the fuel gas inlet side communication holes 14Ca, 1 of the cathode side separator 10 of FIG.
4Cb and the outlet side communication hole 15C are connected to the fuel gas inlet side communication holes 14Aa, 14Aa of the anode side separator 11 of FIG.
Ab and outlet side communication hole 15A are aligned. The electrolyte / electrode structure 7 is sandwiched between the opposed gas flow path surfaces in a state where the respective parts are aligned as described above.

The cathode-side separator 10 and the anode-side separator 1 sandwiching the electrolyte / electrode structure 7
Since a plurality of sets 1 are stacked, the cooling surfaces are opposed to each other in adjacent portions. That is, the oxidant gas inlet-side communication holes 12Ca and 12Ca of the cathode-side separator 10 in FIG.
The Cb and the outlet-side communication holes 13C are connected to the oxidant gas inlet-side communication holes 12Aa, 12Aa of the anode-side separator 11 in FIG.
Ab and outlet side communication hole 13A are aligned. On the other hand, the fuel gas inlet side communication hole 1 of the cathode side separator 10 of FIG.
4Ca, 14Cb and the outlet side communication hole 15C correspond to the fuel gas inlet side communication hole 14 of the anode side separator 11 in FIG.
Aa, 14Ab and outlet side communication hole 15A are aligned.

In the state of being stacked in this manner, the cathode-side separator 10 and the electrolyte / electrode structure 7
The above-mentioned gas (oxidizing gas) flow paths 211 and 212 are formed, and the above-mentioned gas (fuel gas) flow paths 291 and 212 are provided between the anode-side separator 11 and the electrolyte / electrode structure 7.
92 is formed between the anode-side separator 11 and the cathode-side separator 10.
5 are formed.

As shown in FIG. 5, the fuel gas inlet side communication holes 14Ca, 14C of the cathode side separator 10 are provided.
b and the outlet side communication hole 15C are connected to the anode side separator 1
The first fuel gas inlet-side communication holes 14Aa and 14Ab and the outlet-side communication hole 15A are sealed by a seal member CS. FIG. 6 is a sectional view taken along line BB of FIG. In the figure, the extending portion RS1 of the seal member RS is formed so as to form a meandering coolant flow path 25 between the cooling surface of the cathode side separator 10 and the cooling surface of the anode side separator 11.
Are close to each other. In addition, the cathode side separator 1
0 and the gas flow path surface of the anode side separator 11 (the back side of the groove 22 and the groove 30) sandwich the electrolyte / electrode structure 7, and the cathode side separator 10 The cooling surface and the groove 22 and the groove 30 of the cooling surface of the anode-side separator 11 face each other, and a coolant flow path 25 is formed here.

FIG. 7 is a sectional view taken along line CC of FIG. Each protrusion (groove 2) on the gas flow path surface of the cathode separator 10 and the gas flow path surface of the anode separator 11
2 and the back side of the groove 30) sandwich the electrolyte / electrode structure 7, and the cooling surfaces of the cooling surface of the cathode side separator 10 and the cooling surface of the anode side separator 11 are oppositely cooled. The state where the liquid flow path 25 is formed is shown. FIG. 8 is a sectional view taken along the line DD in FIG.
A state in which the grooves 18 and 26 on the gas flow path surface of the cathode-side separator 10 and the gas flow path surface of the anode-side separator 11 form gas flow paths 211 and 291 between the electrolyte / electrode structure 7; Ridges 19 and 27 between the cooling surface of cathode-side separator 10 and the cooling surface of anode-side separator 11
This shows a state in which comrades are closely defining a coolant flow path.
FIG. 9 is a cross-sectional view taken along the line EE in FIG. 2, and each of the seal members AS, CS, RS is provided with an extension portion AS2, CS2, RS.
2 shows a state in which they are in close contact with each other.

In the above embodiment, when the oxidizing gas is supplied to the fuel cell 8, the oxidizing gas is supplied from the oxidizing gas inlet-side communication holes 12Ca and 12Cb of the cathode separator 10 as shown in FIG. Cathode side separator 1
0 is supplied to the gas flow path surface. Then, the extension portion C
U with S1 as a boundary portion and a connecting path 201 as a folded portion
The oxidant gas flows through the U-shaped gas flow path 211 and the U-shaped gas flow path 212 having the extension part CS2 as a boundary and the communication path 202 as a folded part. From the outlet side communication hole 13C.

On the other hand, when the fuel gas is similarly supplied to the fuel cell, the fuel gas is supplied to the fuel gas inlet communication holes 14Aa, 1A of the anode separator 11 as shown in FIG.
4Ab is supplied to the gas flow path surface of the anode-side separator 11. Then, the U-shaped gas flow path 29 having the extension portion AS1 as a boundary portion and the communication path 281 as a folded portion is provided.
1 and a U-shaped gas flow path 292 having the extension portion AS2 as a boundary portion and a communication path 282 as a folded portion, and the reacted gas flows through the fuel gas outlet communication hole 15.
It is discharged from A. Therefore, electric energy is generated between the cathode-side separator 10 and the anode-side serrator 11 through the solid polymer electrolyte membrane by the supplied fuel gas and oxidizing gas, and power is generated.

When the coolant is supplied to the fuel cell,
This cooling liquid is supplied to the cooling surfaces of the separators 10 and 11 from the cooling liquid inlet communication holes 17 of the cathode side separator 10 and the anode side separator 11 as shown in FIGS. Then, the connecting portions 242 and 312 and the connecting routes 241 and 311 are set with the extending portions RS2 and RS1 as boundary portions.
The coolant flows through the meandering coolant channel 25 having the folded portion, and the coolant is discharged from the outlet side communication hole 16 of the coolant. Thereby, the fuel cell can be cooled.

Therefore, in this embodiment, two sets of gas flow paths 211 and 21 of the cathode-side separator 10 are provided.
In 2, the return routes 211B and 212B are superimposed,
Two sets of gas channels 291 and 2 of the anode-side separator 11
In 92, the return paths 291B and 292B are arranged in a superimposed manner, so that the superimposed return paths 291B and 292B are
At 292B, the gas flow rate increases, and as a result, dew water generated in the gas flow path can be effectively discharged. For this reason, the gas flow path surfaces of the separators 10 and 11 are not partially blocked by the dew condensation water, and a uniform reaction can be ensured.

In the above embodiment, both the cathode-side separator 10 and the anode-side separator 11 have the inlet-side communication holes 12Ca, 12Cb and the inlet-side communication holes 1Ca.
From 4Aa, 14Ab to connecting channels 201, 202, connecting channel 2
Compared to the sum of the number of grooves 18 and 26 up to 81 and 282 (4 + 4 = 8), the communication paths 201 and 202, the communication paths 281 and 282, the exit-side communication hole 13C, and the exit-side communication hole Since the number of the grooves 18 and 26 up to 15A is small (5), the flow velocity of each reaction gas can be increased, and condensed water can be effectively discharged. In order to increase the flow rate of the reaction gas, it is necessary to further reduce the number of grooves on the outlet side in consideration of the amount of the reaction gas decreasing by the reaction.

Further, since each of the separators 10 and 11 has two sets of gas flow paths 211 and 212 and gas flow paths 291 and 292, for example, only one gas flow path is used in a low load region. For example, two sets of gas flow paths and one set of gas flow paths can be used depending on the load, so that the apparent electrode density can be appropriately adjusted to increase the system efficiency. Also, in the low load region, one set of gas flow paths can be used, so that, as in the case of using two gas flow paths at low load, more than necessary to maintain the drainage of dew condensation water. Since there is no need to flow the reaction gas and the utilization rate of the reaction gas is increased, the system efficiency can be improved in this respect as well.

The gas flow path inlet AIN and the outlet AOUT of the anode separator 11 are provided on one side (for example, the left side in FIG. 3).
By providing the gas passage inlet CIN and the outlet COUT of 0 on the other side (the left side in FIG. 1), the dew condensation water of the folded portions 281 and 282 of the cathode-side separator 10 in which dew condensation water is apt to accumulate is particularly reduced. In order to permeate and reverse diffuse through the solid polymer electrolyte membrane and move to the gas channel inlet AIN of the anode-side separator 11 to promote the humidification of the reaction gas on the anode side at the inlet side, an apparatus for humidification by that amount is provided. It is possible to reduce the size, and to simplify the auxiliary device for drainage by reducing the amount of drainage. In addition, since the portion where the return paths 211B and 212B of the cathode-side separator 10 with high moisture is overlapped is located at the position where the return paths 291B and 292B of the anode-side separator 11 are overlapped, the return path 291 on the anode side where the water content is low.
B, 292B can be sufficiently humidified by reverse diffusion.

In the above embodiment, the inlet communication holes 12Ca, 12Cb, etc., and the inlet communication holes 14Ca, 14Cb, etc. of the reaction gas are set closer to the outside of each of the separators 10, 11, so that the inside of the separators 10 and 11 is inward. Since the heat radiation effect is high and the temperature is easily lowered as compared with the case of setting, there is an advantage that the relative humidity can be easily maintained at the specified value even if the specified amount of water is not supplied.

The communication paths 201 and 202 of the cathode-side separator 10 and the communication path 2 of the anode-side separator 11
81 and 282 are outbound routes 211A and 212A, respectively, outbound route 2
It functions as a buffer unit for collecting the reaction gases from 91A and 292A. On the other hand, the cathode side separator 1
The gas flow path inlet CIN and the gas flow path outlet COUT of 0 function as buffer portions of the oxidant gas inlet-side communication holes 12Ca and 12Cb and the outlet-side communication hole 13C, and each gas flow path inlet AIN of the anode separator 11. And gas channel outlet A
OUT functions as a buffer portion between the fuel gas inlet communication holes 14Aa and 14b of the cathode separator 11 and the outlet communication hole 15A.

Therefore, even if the grooves 18 and 26 are partially clogged by the condensed water, the reaction gas can be guided to the grooves which are not clogged in the portion functioning as the buffer section. The effective reaction area is not greatly reduced as compared with a case where the gas flow paths are continuously provided without providing the gas passages 281 and 282.
Similarly, each of the grooves 18 and 26 is connected to the inlet side communication hole 12C.
The effective reaction area is not greatly reduced as compared with the case where the a, 14Aa, etc., and the outlet side communication holes 13C, 15A, etc. are provided continuously.

Next, a second embodiment will be described with reference to FIGS. While the first embodiment is a so-called internal manifold type, this embodiment is applied to an external manifold type. FIG. 10 shows a gas flow path surface of the cathode side separator (gas flow path plate) 60, and corresponds to FIG. 1 of the first embodiment. The cathode-side separator 60 is formed by pressing from a metal thin plate, and is provided with four (5), four (4) sets of laterally extending grooves (flow paths) 61 from the upper side.

Except for the left side, the cathode side separator 60 is provided with seal members TS at the edges of the upper side, the lower side, and the right side. Further, the extending portions TS1 and TS2 of the two seal members TS are seamlessly provided from the left side of the cathode-side separator 60 to a position where each set of the grooves 61 is partitioned.
2 extends to just before the right side. In addition, the extension part TS
1, between the right end of TS2 and the sealing member TS,
A communication path 651 and a communication path 652 are respectively formed.
Note that these communication paths 651 and 652 function as buffer sections for collecting upstream gas. Further, the end of the groove 61 on the inlet side communication hole 66Ca side is located at the gas flow path inlet CIN.
The end of the groove 61 on the side of the outlet side communication hole 67C is configured as a gas flow path outlet COUT, and the gas flow path inlet CIN and the gas flow path outlet COUT also function as a buffer section. .

Further, on the left side of the cathode-side separator 60, at positions corresponding to the respective extending portions TS1, FIG.
The three channel-shaped manifold members 62 shown in FIG. Also, three manifold members 62 having the same configuration are mounted on the opposite right side portion for fuel gas. A manifold member 63 for a coolant is attached to each of the upper side and the lower side of the cathode separator 60. In addition, each manifold member 62, 63
Has a seal member 64 attached to the installation portion.

Therefore, the upper and lower manifold members 62 on the left side portion allow the oxidant gas inlet-side manifold 66 to operate.
Ca and 66Cb are formed, and the outlet side manifold 67C for the oxidizing gas is formed by the manifold member 62 at the center. The upper and lower manifold members 6 on the right side
2, the fuel gas inlet side manifolds 68Ca, 68
Cb is formed, and a fuel gas outlet side manifold 69C is formed by the central manifold member 62. In addition, the manifold member 63 on the lower side constitutes a coolant inlet manifold 71, and the manifold member 63 on the upper side constitutes a coolant outlet manifold 70.

As a result, a U-shaped gas (oxidizing gas) flow path 661 having the extension portion TS1 as a boundary portion and the communication path 651 as a folded portion is formed on the gas flow path surface of the cathode side separator 60. A U-shaped gas flow path 662 having the extension portion TS2 as a boundary portion and the communication path 652 as a folded portion.
Are formed. That is, the U-shaped gas flow path 661 is
A forward path 651A from the gas flow path inlet CIN on the inlet side communication hole 66Ca side to the connection path 651 which is a turn-back portion, and a return path 661B from the connection path 651 to the gas flow path exit COUT on the outlet side communication hole 67C side. The U-shaped gas flow path 662 includes a forward path 662A from the gas flow path inlet CIN on the inlet-side communication hole 66Cb side to a communication path 652, which is a folded portion, and the communication path 652 to the outlet-side communication hole 67C. Return path 662B to the side gas flow path outlet COUT
It is composed of Therefore, the cathode side separator 6
The gas flow path 661 and the gas flow path 662
Are provided, and each gas flow path 661, 66
The two return routes 661B and 662B are arranged to overlap each other.

FIG. 12 shows the cathode separator 6 of FIG.
0 shows the cooling surface on the back surface. The groove 61
A protrusion 72 is formed at a position on the back side of. In this cooling surface, the left side of the upper side and the right side of the lower side are cutouts K1, respectively.
A seal member TS is provided on the edge except for K2. An extension TS1 of the seal member TS extends from a slightly upper portion of the center of the left side portion of the cathode side separator 60 to a position partitioning each set of the ridges 72 to a position just before the right side portion. On the other hand, the extending portion TS2 of the sealing member TS is seamlessly positioned from a slightly lower side of the center of the right side of the cathode-side separator 60 to a position partitioning each set of the ridges 72.
Extends to the left side.

A communication path 681 is formed between the right end of the extension TS1 and the seal member TS. A communication path 682 is formed between the left end of the extension TS2 and the seal member TS. As described above, on the right side, three channel-shaped manifold members 62 as shown in FIG. 11 are attached at positions corresponding to the respective extending portions TS1 for oxidizing gas.
Also, three manifold members 62 of the same configuration are mounted on the opposite left side portion for fuel gas.
A manifold member 63 for a coolant is attached to each of the upper side and the lower side of the cathode separator 60.

Therefore, a meandering coolant (ethylene glycol) flow path 69 is formed on the cooling surface of the cathode-side separator 60 with the extension portions TS2 and TS1 as boundaries and the communication paths 682 and 681 turned back. . Although only the cathode-side separator 60 has been described, each part of the anode-side separator is formed in the same positional relationship as in the first embodiment.

Therefore, also in the second embodiment, the same effect as that of the first embodiment can be obtained by the external manifold type. That is, in the two gas flow paths 661 and 662 of the cathode separator 60, the return paths 661B and 662B are overlapped, and the return path is also overlapped in the anode separator, so that the gas flow rate increases in the overlapped return path. And
Condensed water generated in the gas flow path can be effectively discharged. Therefore, a uniform reaction can be ensured.

In addition, by using both or one of the two gas flow paths in accordance with the size of the load, the apparent electrode density can be appropriately adjusted to increase the system efficiency. Also, in the low load region, one set of gas flow paths can be used, so that, as in the case of using two gas flow paths at low load, more than necessary to maintain the drainage of dew condensation water. Since there is no need to flow the reaction gas and the utilization rate of the reaction gas is increased, the system efficiency can be improved in this respect as well. Then, the cathode side separator 60
Since the turn-back side of the oxidizing gas flowing through the gas flow path surface is set on the inlet side of the fuel gas flowing through the gas flow path surface of the anode-side separator, the humidifier can be downsized and the amount of drainage can be reduced. The device for drainage can be simplified by the minute. And since the said buffer part and especially the communication paths 651 and 652 can be made to function as a buffer part, even if dew condensation water closes a part of groove | channel, the communication paths 651 and 652 which function as a buffer part.
Thereby, the reaction gas can be flowed to another groove, and therefore, the effective reaction area is not greatly reduced.

The present invention is not limited to the above embodiment, and is applicable to, for example, a molten carbonate fuel cell as well as a polymer electrolyte fuel cell. Also, the press-formed metal separator was described,
The present invention can also be applied to a separator in which a groove is formed by cutting a plate material made of a molded carbon material. And
In each embodiment, the case where the gas flow path is formed by extending the seal member has been described. However, the gas flow path may be formed by joining the seal member and the ridge. In addition, the present invention is not limited to the case where a part of the gas flow path is formed by the sealing material, and can be applied to the case where the gas flow path is formed only by press molding.

[0068]

As described above, according to the first aspect of the present invention, the flow velocity of the reactant gas in the superimposed return path is increased, and thereby the dew water generated in the gas flow path is effectively reduced. Gas can be discharged, and a gas flow path without clogging can be secured.

According to the second aspect of the present invention, when the fuel cell is operating, even if dew water accumulates in the gas flow path of the separator, the flow velocity of the reaction gas in the overlapped return path increases, As a result, the condensed water generated in the gas flow path can be effectively discharged, so that a uniform reaction on the gas flow path surface of the separator can be ensured. In addition, the apparent electrode density can be appropriately adjusted because the reaction gas flow area in the electrode can be changed by selectively using two sets of U-shaped gas flow paths and one set of gas flow paths according to the load. System efficiency. In the low-load region, one set of gas flow paths can be used. Therefore, as in the case of using two gas flow paths at low load, more than necessary to maintain the drainage of dew condensation water. Since there is no need to flow the reaction gas, the utilization rate of the reaction gas is increased, and in that respect, the system efficiency can be increased.

According to the third aspect of the present invention, the condensed water at the turn-back portion of the separator on the cathode electrode side where the dew water easily accumulates penetrates through the electrolyte and reversely diffuses, so that the gas flow inlet side of the separator on the anode electrode side. In order to promote the humidification of the reaction gas on the anode electrode side, the size of the device for humidification can be reduced by that much, and the accompanying device for drainage can be simplified by reducing the amount of drainage. Further, since the portion where the return path of the separator on the cathode electrode side with a large amount of water is overlapped with the part where the return path of the separator on the anode electrode side is overlapped, the return path on the anode side where the water content is low is sufficiently reduced by reverse diffusion. Can be humidified.

According to the fourth aspect of the present invention, even if a part of the gas flow path is clogged with the dew condensation water, the reaction gas flows into another flow path not clogged with the dew condensation water through the buffer section. Therefore, it is possible to prevent the gas flow path from being completely clogged and to eliminate the non-uniformity of the reaction.

According to the fifth aspect of the present invention, even if one gas flow path is clogged, the reaction gas can be supplied through another gas flow path. The reliability is improved as compared with the case.

According to the invention described in claim 6, the flow velocity of the reaction gas in the return path with respect to the outward path can be reliably increased, and the drainage of the condensed water can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a cathode-side separator according to a first embodiment of the present invention.

FIG. 2 is a rear view of FIG.

FIG. 3 is a plan view of the anode-side separator according to the first embodiment of the present invention.

FIG. 4 is a rear view of FIG. 3;

FIG. 5 is a cross-sectional view of the fuel cell taken along line AA of FIG.

FIG. 6 is a sectional view of the fuel cell taken along the line BB of FIG. 2;

FIG. 7 is a sectional view of the fuel cell taken along the line CC of FIG. 2;

FIG. 8 is a sectional view of the fuel cell taken along the line DD in FIG. 2;

9 is a cross-sectional view of the fuel cell taken along the line EE in FIG.

FIG. 10 is a plan view of a cathode-side separator according to a second embodiment of the present invention.

FIG. 11 is a perspective view of a manifold member according to a second embodiment of the present invention.

FIG. 12 is a rear view of FIG. 10;

FIG. 13 is a plan view of a conventional technique.

[Description of Signs] 7 Electrolyte / electrode structure 10 Cathode-side separator (gas flow path plate) 11 Anode-side separator (gas flow path plate) 18, 26 Groove (flow path) 211A, 212A, 291A, 292A Outbound paths 201, 202 , 281, 282 Connecting path (returned part) 211B, 212B, 291B, 292B Return path 211, 212, 291, 292 Gas flow path CIN, AIN Gas flow path inlet COUT, AOUT Gas flow path outlet

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Hideaki Kikuchi, Inventor 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Seiji Suzuki 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 5H026 AA06 CC03 CC08 HH02

Claims (6)

[Claims] 1. A rectangular gas flow path plate having conductivity for a fuel cell, comprising a gas flow path, a reaction flow gas supply port, a reaction flow path, a return path, a return path, and a return path. A gas flow path for a fuel cell, wherein two sets of U-shaped gas flow paths leading to a gas flow path outlet for discharging gas are provided, and these two sets of gas flow paths are arranged such that a return path portion is overlapped. Board. 2. A fuel cell in which an electrolyte / electrode structure in which an electrolyte is sandwiched between an anode electrode and a cathode electrode is sandwiched between a pair of separators, wherein a rectangular gas flow facing the anode electrode or the cathode electrode of the separator is provided. On the road surface,
Two sets of U-shaped gas flow paths are provided from the gas flow path inlet for supplying the reaction gas to the gas flow path outlet for discharging the reaction gas through the outward path, the turn-back portion, and the return path. A fuel cell, wherein a return path is overlapped and arranged on the gas flow path surface. 3. An inlet and an outlet of a gas channel of the separator on the anode electrode side are provided on one side, and an inlet and an outlet of a gas channel of the separator on the cathode electrode side are provided on the other side. The fuel cell according to claim 2, wherein 4. The fuel cell according to claim 2, wherein the folded portion is formed as a buffer portion. 5. The fuel cell according to claim 2, wherein the gas flow path includes a plurality of flow paths. 6. The method according to claim 2, wherein the sum of the cross-sectional areas of the two outward paths is larger than the sum of the cross-sectional areas of the return paths.
The fuel cell according to claim 5.