JP2002050392A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively make the whole fuel cell stack compact size and ensures good drainage. SOLUTION: The fuel cell stack 10 is designed in a rectangular parallelepiped as a whole, and an oxidant gas passage groove 48a, 48b and a fuel gas passage groove 50a, 50b, which are divided in the longitudinal direction, are provided in the first and the second separator 14, 16. An inner side cooling medium passage 60 is provided through nearly the center of the first and the second separator 14, 16 and outer side cooling medium passages 62a, 62b are provided through the both side edges of the longitudinal side of the first and the second separator 14, 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell stack in which a plurality of unit fuel cells each having a solid polymer electrolyte membrane sandwiched between an anode and a cathode are stacked with a separator interposed therebetween.

[0002]

2. Description of the Related Art For example, a polymer electrolyte fuel cell is a unit in which an anode electrode and a cathode electrode are opposed to each other on both sides of an electrolyte membrane composed of a polymer ion exchange membrane (cation exchange membrane). The fuel cell is constituted by sandwiching the fuel cell between separators. This polymer electrolyte fuel cell is usually used as a fuel cell stack by stacking a predetermined number of unit fuel cells and separators.

In this type of fuel cell stack, a fuel gas, for example, a hydrogen-containing gas, supplied to an anode electrode is hydrogen-ionized on a catalyst electrode, and is humidified through a moderately humidified electrolyte membrane. The electrons generated during the movement are taken out to an external circuit and used as DC electric energy. On the cathode side electrode,
Since an oxidizing gas, for example, an oxygen-containing gas or air is supplied, the hydrogen ions, the electrons, and the oxygen gas react at the cathode-side electrode to generate water.

When the above-described fuel cell stack is mounted on a vehicle or the like and used, a considerably large number of unit fuel cells are required in order to obtain desired power. Therefore, the size of the entire fuel cell stack tends to increase,
It is desired to make the components of the fuel cell stack thinner in the stacking direction. Further, when mounted on a vehicle, it is most practical to install the fuel cell stack under the floor of the vehicle, and in order to secure a sufficient living space in the vehicle cabin, the height dimension of the entire fuel cell stack must be reduced. Must be set lower.

Therefore, for example, in US Pat.
As disclosed in Japanese Patent Publication No. 326, the entire fuel cell stack is formed in a rectangular parallelepiped shape, and a communication hole is provided in the stacking direction of unit fuel cells without providing a cooling medium flow path in the plane of the separator. There is known a fuel cell stack in which a cooling medium flows through the communication hole. Specifically, as shown in FIG. 11, the fuel cell stack 1 is stacked in the vertical direction (the direction of arrow X), and end plates 2 are provided at both upper and lower ends.
a, 2b are provided.

A flow path plate 3 serving as a separator is disposed between the end plates 2a and 2b, and an oxidizing gas supply port 4 is provided at both short side edges of the flow path plate 3.
a and fuel gas supply port 5a, and oxidant gas discharge port 4b
And a fuel gas outlet 5b. The oxidizing gas supply port 4a and the oxidizing gas discharge port 4b are connected to each other by an oxidizing gas flow groove 6 which is turned on the long side in the plane of the flow path plate 3 and meanders. A plurality of through holes 7 penetrating in the stacking direction are provided at both ends of the long side of the flow path plate 3, and a cooling medium passage 8 is formed through the through holes 7. The cooling medium flows in the direction indicated by the arrow along the arrow.

Therefore, when the fuel cell stack 1 configured as described above is used for a vehicle, the end of the long side is installed on the floor surface, so that the height of the entire fuel cell stack 1 in the height direction is increased. The dimensions will be set effectively low.
In this case, the flow path plate 3 is not provided with a cooling medium flow path along its surface, and the thickness of the flow path plate 3 in the stacking direction is configured to be as thin as possible. The dimension of the fuel cell stack 1 in the stacking direction is shortened.

[0008]

However, as described above, the long side of the through-hole 7 is provided at the both side edges of the short side. The distance from the cooling medium must be set short, and the aspect ratio (aspect ratio) of the flow path plate 3 must be increased. Therefore, the oxidizing gas passage groove 6 (and the fuel gas passage groove not shown) provided in the passage plate 3.
Is considerably lengthened, and the long side of the fuel cell stack 1 is installed in the horizontal direction, so that the oxidant gas flow channel groove 6 meanders in the vertical direction.

As a result, it becomes difficult for the generated water condensed in the oxidizing gas passage groove 6 to move in the anti-gravity direction along the oxidizing gas passage groove 6, and It has been pointed out that the generated water remains and the power generation performance of the fuel cell stack 1 is reduced.

The present invention solves this kind of problem, and provides a fuel cell stack capable of easily reducing the size of the entire stack, securing drainage performance, and obtaining desired power generation performance. The purpose is to:

[0011]

In the fuel cell stack according to the first aspect of the present invention, the plane of the separator is set in a rectangular shape, and the plane of the separator is a reaction gas containing a fuel gas and / or an oxidant gas. A reaction gas flow path for flowing gas is provided divided into a plurality of parts in the long side direction, and an outer cooling medium flow path is formed while being penetrated in the lamination direction on the outer periphery of the reaction gas flow path, and is divided. Further, an inner coolant passage is provided between the reaction gas passages so as to penetrate in the stacking direction.

As described above, since the reaction gas flow path is divided in the long side direction, the degree of freedom in the layout of each reaction gas flow path is improved, and the length of each reaction gas flow path is greatly shortened. The generated water is easily discharged. Moreover, since the inner cooling medium flow path is provided between the divided reaction gas flow paths, the thickness of the separator in the stacking direction can be reduced as much as possible while reliably maintaining the desired cooling function. become. Therefore, the size of the entire fuel cell stack can be easily reduced.

[0013] In the fuel cell stack according to the second aspect of the present invention, the reaction gas flow path is formed in a meandering shape that is folded on the short side of the plane and extends toward the long side. For this reason, when the fuel cell stack is disposed with the long side facing the horizontal direction, the reaction gas flow path is directed in the direction of gravity. As a result, the generated water condensed in the reaction gas flow path can easily move in the direction of gravity, and the generated water can be reliably discharged from the reaction gas flow path.

Further, in the fuel cell stack according to the third aspect of the present invention, the flow directions of the respective coolants in the outer coolant channel and the inner coolant channel are set in opposite directions. For this reason, for example, by supplying the cooling medium from the inner cooling medium flow path and discharging the cooling medium to the outer cooling medium flow path, a relatively low-temperature cooling medium is supplied to a central portion in the fuel cell stack, which usually has a high temperature. And the temperature in the fuel cell stack can be maintained uniform.

[0015]

FIG. 1 is a schematic perspective explanatory view of a fuel cell stack 10 according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view of a main part of the fuel cell stack 10.

The fuel cell stack 10 includes a unit fuel cell 12 and first and second separators 14 and 16 sandwiching the unit fuel cell 12, and a plurality of these units are arranged in a horizontal direction (direction of arrow A). Are laminated. The fuel cell stack 10 has a rectangular parallelepiped shape as a whole, and is arranged with the short side direction (arrow B direction) oriented in the gravity direction and the long side direction (arrow C direction) oriented in the horizontal direction. .

The unit fuel cell 12 has a solid polymer electrolyte membrane 18, a cathode electrode 20 and an anode electrode 22 disposed with the electrolyte membrane 18 interposed therebetween. The anode-side electrode 22 has first and second gas diffusion layers 24 and 26 made of, for example, porous carbon paper as a porous layer.
Is arranged. Cathode side electrode 20, anode side electrode 2
The two and the first and second gas diffusion layers 24 and 26 are divided into a plurality, for example, two in the long side direction.

First and second gaskets 28, 30 are provided on both sides of the unit fuel cell 12, and the first gasket 28 is for accommodating the cathode 20 and the first gas diffusion layer 24, respectively. Large opening 32
a, 32b, while the second gasket 30
Anode side electrode 22 and second gas diffusion layer 26
Have large openings 34a and 34b for accommodating therein. The unit fuel cell 12 and the first and second gaskets 28, 30 form first and second separators 14, 16.
Pinched by

The first separator 14 is a cathode-side electrode 2
The surface 14a facing 0 and the surface 14b on the opposite side are set in a rectangular shape. For example, the long side 35a is oriented in the horizontal direction, and the short side 35b is oriented in the direction of gravity.

Oxidant gas inlets 36a and 36b for passing an oxygen-containing gas or an oxidant gas, which is air, are provided at a substantially central portion on one side of the long side 35a of the first separator 14 and one edge portion thereof. The oxidant gas inlet 36
Fuel gas inlets 38a and 38b for passing a fuel gas such as a hydrogen-containing gas are provided in the vicinity of the fuel gas inlets a and 36b. On the lower side of the long side 35a side of the first separator 14,
The oxidizing gas outlets 36c and 36d and the fuel gas outlet 38c,
38d are provided alternately.

At a substantially central portion of the first separator 14, a cooling medium inlet 40a is provided extending in a short side direction (vertical direction), and a short side 35b of the first separator 14 is provided.
The cooling medium outlet 4 extends in the up-down direction
0b and 40c are provided. The cooling medium inlet 40a has bent portions extending toward the fuel gas inlet 38b and the fuel gas outlet 38c at both upper and lower edges on the long side 35a side, and is formed so as to penetrate in the thickness direction of the first separator 14. ing. The cooling medium outlets 40b and 40c have bent portions extending to the fuel gas inlet 38a and the fuel gas outlet 38d at upper and lower end edges on the long side 35a side, and penetrate in the thickness direction of the first separator 14. Formed.

The cooling medium inlet 40a and the cooling medium outlet 40
Ribs 42 for maintaining the strength of the first separator 14 may be provided to b and 40c as needed (FIG. 2).
(See the middle and two-dot chain lines.) As shown in FIG. 3, ribs 44 are provided at the four corners of the first separator 14 and substantially at the center of the cooling medium inlet 40a, and a hole 46 is formed in the rib 44, and a tie rod 47 is inserted through the hole 46. May be configured. A cooling medium such as pure water, ethylene glycol or oil is supplied to the cooling medium inlet 40a.

As shown in FIG. 2, a plurality of independent oxidizing gas passage grooves (reactive gas passages) 48a, 48b communicating with the oxidizing gas inlets 36a, 36b are formed on the surface 14a of the first separator 14. Are provided in the gravitational direction while meandering in the horizontal direction, and the oxidizing gas passages 48a and 48b are downstream of the oxidizing gas outlets 36c and 36b.
It communicates with c.

The second separator 16 is formed in a rectangular shape, and like the first separator 14, the oxidant gas inlets 36a and 36b, the fuel gas inlets 38a and 38b, the oxidant gas outlets 36c and 36d, and the fuel gas outlet 38c, 38
d, cooling medium inlet 40a and cooling medium outlet 40b, 4
0c is formed to penetrate the second separator 16 in the thickness direction.

As shown in FIG. 4, a fuel gas inlet 3 is provided on the surface 16a of the second separator 16 on the side of the anode 22.
A plurality of independent fuel gas passage grooves (reaction gas passages) 50a and 50b are formed in communication with the fuel gas passages 8a and 38b. The fuel gas passage grooves 50a and 50b are provided in the direction of gravity while meandering in the horizontal direction, and communicate with the fuel gas outlets 38c and 38d.

As shown in FIG. 1, the unit fuel cells 12
Is an arrow A through the first and second separators 14 and 16.
The first end plate 52 and the second end plate 54 are disposed at both ends in the stacking direction, and are integrally tightened via tie rods 47 (see FIG. 3). The fuel cell stack 10 is configured.

As shown in FIG. 5, the fuel cell stack 10
Inside, the oxidizing gas inlets 36a, 36b and the oxidizing gas outlets 36c, 36d formed in the first and second separators 14, 16 and the first and second gaskets 28, 30 and the electrolyte membrane 18 communicate with each other. Oxidant gas supply / discharge passages 56a, 56b formed in a substantially U-shape and a fuel gas inlet 3
8a, 38b and the fuel gas outlets 38c, 38d communicate with each other to form a substantially U-shaped fuel gas supply / discharge passage 58a, 58b.
8b, an inner coolant passage 60 formed by communicating the coolant inlet 40a, and outer coolant passages 62a, 62b formed by communicating the coolant outlets 40b, 40c.

The second end plate 54 passes through the cooling medium inlet 40a and is arranged rearward in the stacking direction (the second end plate 5).
4), the cooling medium flowing to the cooling medium outlets 40b, 40c is divided into left and right sides, and the outer cooling medium passage 6 communicates with the cooling medium outlets 40b, 40c.
A distribution passage 64 for supplying to 2a and 62b is formed.

The first end plate 52 has a piping structure 7
0 is provided. As shown in FIG.
Is an oxidizing gas supply pipe 72 communicating with the inlet side of the oxidizing gas supply / discharge paths 56a and 56b;
a, an oxidizing gas discharge pipe 74 communicating with the outlet side of 56b
A fuel gas supply pipe 76 communicating with the inlet sides of the fuel gas supply / discharge paths 58a, 58b, a fuel gas discharge pipe 78 communicating with the exit side of the fuel gas supply / discharge path 58b, and the inner cooling medium flow path 60. A cooling medium supply pipe 80 communicating with the cooling medium supply pipe 80 and a cooling medium discharge pipe 82 communicating with the outer cooling medium flow paths 62a and 62b are provided.

The fuel cell stack 1 configured as described above
The operation of 0 will be described below.

As shown in FIG. 1, the oxidizing gas supply pipe 72
In addition, air or an oxygen-containing gas (hereinafter simply referred to as air) is supplied as an oxidant gas, and a fuel gas (for example, a gas containing hydrogen obtained by reforming hydrocarbon) is supplied to the fuel gas supply pipe 76. Further, a cooling medium is supplied to the cooling medium supply pipe 80. The air supplied to the oxidizing gas supply pipe 72 is, as shown in FIG.
After being distributed to the first and second separators a and 56b, they are supplied to oxidant gas inlets 36a and 36b provided in the first separator 14.

As shown in FIG. 2, in the first separator 14, air supplied to the oxidizing gas inlets 36a and 36b is introduced into the oxidizing gas flow grooves 48a and 48b in the surface 14a. It moves in the direction of gravity while meandering horizontally along the gas flow grooves 48a and 48b. that time,
The oxygen gas in the air is supplied from the first gas diffusion layer 24 to the cathode electrode 20, while the unused air is discharged to the oxidizing gas outlets 36c and 36d. The air discharged to the oxidizing gas outlets 36c and 36d is discharged to the outside of the fuel cell stack 10 via the oxidizing gas discharge pipe 74 provided on the outlet side of the oxidizing gas supply / discharge paths 56a and 56b. You.

On the other hand, the fuel gas supplied to the fuel gas supply pipe 76 is distributed to the fuel gas supply / discharge passages 58a, 58b, and then is supplied to the fuel gas inlets 38a, 38b of the second separator 16.
Sent to As shown in FIG. 4, the fuel gas inlet 38a,
The fuel gas introduced into the fuel gas flow channel groove 50 b
a, 50b, the second separator 1
6 while moving in the horizontal direction along the surface 16a in the direction of gravity. At that time, the hydrogen gas in the fuel gas is supplied to the anode 22 of the unit fuel cell 12 through the second gas diffusion layer 26.

The unused fuel gas is led out from the fuel gas flow grooves 50a, 50b to the fuel gas outlets 38c, 38d, and is discharged from the fuel gas supply / discharge passages 58a, 58b to the fuel gas discharge pipe 78. Is done. As a result, power is generated in each unit fuel cell 12 and the fuel cell stack 1
Electric power is supplied to a load connected to 0, for example, a motor (not shown).

The inside of the fuel cell stack 10 is cooled by a cooling medium. That is, as shown in FIG. 5, the cooling medium supplied to the cooling medium supply pipe 80 is introduced into the inner cooling medium flow path 60 and is formed in the unit fuel cell 12 and the first and second separators 14 and 16. It moves rearward in the stacking direction through the cooling medium inlet 40a. At this time, the cooling medium passes through the substantially central portion of each unit fuel cell 12, cools the unit fuel cell 12 from the center side, and distributes the second end plate 54 disposed on the rear side in the stacking direction. It is introduced into the passage 64.

The cooling medium introduced into the distribution passage 64 moves to both ends in the direction of the arrow C and moves to the outer cooling medium passage 62.
a, 62b. Outer cooling medium channels 62a, 6
The cooling medium flowing through 2b is discharged from the cooling medium discharge pipe 82 after cooling each fuel cell 12 from the outside.

In this case, in the first embodiment, the entire fuel cell stack 10 is set in a rectangular parallelepiped shape, and the surfaces 14a, 16a of the first and second separators 14, 16 are formed.
Include oxidizing gas flow channels 48a, 4g,
8b and the fuel gas passage grooves 50a, 50b are formed by being divided in the long side direction (the direction of arrow C). Between the oxidizing gas passage grooves 48a, 48b and the fuel gas passage grooves 50a, 50
b, an inner cooling medium flow path 60 for flowing the cooling medium.
A cooling medium inlet 40a is formed,
Cooling medium outlets 40b, 40c which are located outside the oxidizing gas flow grooves 48a, 48b and the fuel gas flow grooves 50a, 50b and form outer cooling medium flow paths 62a, 62b for flowing a cooling medium. Is provided.

For this reason, the unit fuel can be supplied only by flowing the cooling medium from the inner cooling medium passage 60 provided through the unit fuel cells 12 in the stacking direction along the outer cooling medium passages 62a and 62b. The power generation surface of the battery cell 12 can be satisfactorily cooled from the inside and the outside, and the surface 14b of the first separator 14 or the surface 16 of the second separator 16 can be cooled.
There is no need to form a coolant flow channel along the surface direction on the b side. Accordingly, the thickness of the first separator 14 or the second separator 16 in the stacking direction is made as thin as possible, and the dimension of the fuel cell stack 10 in the stacking direction is effectively shortened, so that the fuel cell stack 10 is downsized. Can be easily achieved.

Further, the oxidizing gas passage grooves 48a and 48b and the fuel gas passage grooves 50a and 50b which are reaction gas passages.
b is divided in the long side direction of the first and second separators 14 and 16. For this reason, the oxidant gas flow channel groove 48
a, 48b and the pattern layout of the fuel gas flow grooves 50a, 50b are improved. As a result, the oxidizing gas passage grooves 48a and 48b and the fuel gas passage grooves 50
The a and 50b can be configured as serpentine channels meandering in the horizontal direction and moving in the direction of gravity, and the generated water is reliably discharged, and the power generation performance of the fuel cell stack 10 is reliably prevented from lowering. It becomes possible. Note that the reaction gas flow path can be divided into two or more in the long side direction, and can be set to three divisions, four divisions, or the like depending on the aspect ratio or the like.

Further, in the first embodiment, after supplying the cooling medium to the inner cooling medium flow path 60, the cooling medium is supplied through the distribution passage 64 of the second end plate 54 to the outer cooling medium flow paths 62 a, 62 a. 62b, and is discharged from the outlet side of the outer cooling medium channels 62a, 62b. Therefore, in each unit fuel cell 12, a cooling medium having a low temperature is supplied to a substantially central portion having a high temperature, and there is an advantage that the cooling efficiency of the unit fuel cell 12 is effectively improved.

As shown in FIG. 1, a predetermined number of unit fuel cells 12
The conductive plate 90 may be interposed every interval. This conductive plate 90
Is cooled relatively quickly in the surface direction by the passage of the cooling medium, so that the power generation surface of each unit fuel cell 12 in contact with the surface of the conductive plate 90 is more efficiently cooled. .

As shown in FIG. 6, in the inner cooling medium flow path 60, the rear side in the stacking direction (the cooling medium flow direction).
If the through-holes (cooling medium inlet 40a) of the second separator 16 are sequentially made to protrude in a stepwise manner, the contact area between the portion forming the step portion of the second separator 16 and the cooling medium increases. Then, the second separator 16 can be cooled more efficiently. The second separator 1
Alternatively, in addition to the second separator 16, a through-hole of the first separator 14 may be projected in a stepped manner.

FIG. 7 is an explanatory front view of a first separator 100 constituting a fuel cell stack according to a second embodiment of the present invention. Note that the same components as those of the first separator 14 configuring the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

One surface 10 of the first separator 100
0a, an oxidizing gas passage groove 10 communicating the oxidizing gas inlets 36a, 36b and the oxidizing gas outlets 36c, 36d.
2a and 102b are formed. Oxidant gas channel groove 102
a and 102b constitute a straight flow path extending in the vertical direction, and thereby, the oxidizing gas flow path groove 10 is formed.
It is possible to discharge the generated water condensed in 2a and 102b more smoothly and reliably.

Although not shown in the second embodiment, the fuel gas inlets 38a, 38b and the fuel gas outlet 3
8c and 38d are configured to communicate with each other through a fuel gas flow channel groove that forms a straight flow channel.

FIG. 8 is an explanatory front view of one surface 120a of a first separator 120 constituting a fuel cell stack according to a third embodiment of the present invention, and FIG. It is front explanatory drawing of the surface 122a.

First and second separators 120 and 122
An oxidizing gas inlet 124a and a fuel gas inlet 126a sandwiching the oxidizing gas inlet 124a
The fuel gas outlet 126c is formed through the fuel gas outlet 126c.
Oxidant gas outlets 124b and 124c are formed with 6c interposed therebetween.

First and second separators 120 and 122
A cooling medium inlet 128a is formed substantially at the center of
Cooling medium outlets 128b and 128c are formed through the first and second separators 120 and 122 at both ends on the short side. The cooling medium inlet 128a and the cooling medium outlets 128b, 128c are set in a rectangular shape extending in the vertical direction.

As shown in FIG. 8, the first separator 120
A plurality of oxidizing gas flow grooves 130a, 130b are respectively formed on the left and right surfaces 120a from the oxidizing gas inlet 124a.
Are provided in the direction of gravity while meandering in the horizontal direction, and communicate with the oxidizing gas outlets 124b and 124c.

As shown in FIG. 9, the second separator 122
Each of the plurality of fuel gas flow channel grooves 1
32a, 132b are fuel gas inlets 126a, 126b
The fuel gas outlet 126c is provided in the direction of gravity while meandering in the horizontal direction in communication with the fuel gas outlet 126c.

In the third embodiment configured as described above, the air supplied to the oxidizing gas inlet 124a moves inside the surface 120a while meandering along the oxidizing gas flow grooves 130a and 130b. Unused air is discharged to the oxidizing gas outlets 124b and 124c. On the other hand, the fuel gas introduced into the fuel gas inlets 126a, 126b moves in the surface 122a along the fuel gas flow grooves 132a, 132b, and unused fuel gas is discharged from the fuel gas outlet 126c.

Then, the cooling medium is introduced into a cooling medium inlet 128a formed through substantially the center of the first and second separators 120 and 122, and cools the electrode surface from the center. Next, the cooling medium is supplied to the cooling medium outlet 128b,
By flowing through 128c, the electrode surface is cooled from the outside, whereby the cooling of the electrode surface is performed smoothly and reliably.

FIG. 10 is an explanatory view of the flow path of the fuel cell stack 140 according to the fourth embodiment of the present invention. Note that the same components as those in the flow path explanatory diagram shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Coolant inlets 146a, 146b and 146c are vertically formed at the center of the first and second separators 142 and 144 of the fuel cell stack 140, and both ends of the long sides are formed. Coolant outlets 148a, 148b at the edges in the vertical direction
148c and the cooling medium outlets 148d, 148e and 148f are formed therethrough. Fuel cell stack 1
Inside 40, cooling medium inlets 146a to 146c are communicated to form an internal cooling medium flow path 150, and cooling medium outlets 148a to 148c and cooling medium outlets 148 are formed.
d to 148f to communicate with the outer cooling medium channels 152a,
52b are formed.

The fuel cell stack 1 configured as described above
In 40, the cooling medium supplied to the inner cooling medium flow path 150 is turned back in the stacking direction in the fuel cell stack 140 and introduced into the cooling medium inlets 146 a to 146 c to cool the central part of the power generation surface. Further, the cooling medium is introduced into the outer cooling medium flow paths 152a and 152b, and after being cooled from outside the power generation surface through the cooling medium outlets 148a to 148c and 148d to 148f, is discharged outside.

Thus, in the fuel cell stack 140, the cooling medium flows along the relatively long inner cooling medium passage 150 and the outer cooling medium passages 152a and 152b, so that the power generation surface can be more reliably cooled. The effect is obtained.

In the first to fourth embodiments described above, the oxidizing gas and the fuel gas are configured to flow downward from above. However, the oxidizing gas and the fuel gas are discharged from below. You may make it flow upward.

[0058]

In the fuel cell stack according to the present invention, a plurality of reaction gas flow paths are formed in the plane of the separator set in a rectangular shape while being divided in the long side direction.
An outer cooling medium flow path is formed on the outer periphery of the reaction gas flow path, and an inner cooling medium flow path is provided between the reaction gas flow paths. Therefore, it is not necessary to form a cooling medium flow channel in a plane, and the unit fuel cells can be easily and reliably cooled, and the thickness of the separator in the thickness direction is reduced as much as possible. This makes it possible to easily reduce the size of the entire fuel cell stack.

[Brief description of the drawings]

FIG. 1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part of the fuel cell stack.

FIG. 3 is another first example incorporated in the fuel cell stack;
It is a front explanatory view of a separator.

FIG. 4 is an explanatory front view of one surface of a second separator incorporated in the fuel cell stack.

FIG. 5 is an explanatory view of a flow path in the fuel cell stack.

FIG. 6 is an explanatory view when a through hole of a separator is arranged stepwise in the fuel cell stack.

FIG. 7 is an explanatory front view of one surface of a first separator constituting a fuel cell stack according to a second embodiment of the present invention.

FIG. 8 is an explanatory front view of one surface of a first separator constituting a fuel cell stack according to a third embodiment of the present invention.

FIG. 9 is an explanatory front view of one surface of a second separator included in the fuel cell stack according to the third embodiment.

FIG. 10 is an explanatory view of a flow path in a fuel cell stack according to a fourth embodiment of the present invention.

FIG. 11 is a perspective view of a fuel cell stack according to the related art.

[Description of Signs] 10, 140: Fuel cell stack 12: Unit fuel cells 14, 16, 100, 120, 122, 142, 144
... separator 18 ... electrolyte membrane 20 ... cathode side electrode 22 ... anode side electrode 28, 30 ... gasket 36a, 36b, 124a ... oxidant gas inlet 36c, 36d, 124b, 124c ... oxidant gas outlet 38a, 38b, 126a, 126b ... fuel gas inlets 38c, 38d, 126c ... fuel gas outlets 40a, 128a, 146a to 146c ... cooling medium inlets 40b, 40c, 128b, 128c, 148a to 14
8f Cooling medium outlet 48a, 48b, 102a, 102b, 130a, 13
0b: Oxidizing gas flow grooves 50a, 50b, 132a, 132b: Fuel gas flow grooves 52, 54: End plates 56a, 56b: Oxidizing gas supply / discharge paths 58a, 58b: Fuel gas supply / discharge paths 60, 150 ... Inner cooling medium flow path 62a, 62b, 152a, 152b ... outer cooling medium flow path 70 ... piping structure

Claims (3)

[Claims] 1. A fuel cell stack in which a plurality of unit fuel cells each comprising a solid polymer electrolyte membrane sandwiched between an anode electrode and a cathode electrode are stacked with a separator interposed therebetween, wherein the separator is The plane is set to a rectangular shape, and a flow of a reaction gas, which is at least one of a fuel gas and an oxidizing gas, is performed on the plane, and a plurality of reaction gas flow paths divided into a plurality in a long side direction. An outer coolant passage that penetrates in the stacking direction of the unit fuel cells and is arranged on the outer periphery of the reactant gas passage to allow a coolant to flow; A fuel cell stack, wherein the fuel cell stack is provided between the reaction gas flow paths and an internal cooling medium flow path for flowing a cooling medium. 2. The fuel cell stack according to claim 1, wherein the reactant gas flow path is formed in a meandering shape that is folded at a short side of the plane and extends toward a long side. . 3. The fuel cell stack according to claim 1, wherein a flow direction of the cooling medium in the outer cooling medium flow path is set to be opposite to a flow direction of the cooling medium in the inner cooling medium flow path. A fuel cell stack, characterized in that: