JP2003187838A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain an excellent power generation performance by reducing the volume of humidifying water and surely preventing generation of condensation, using a simple configuration. <P>SOLUTION: A fuel stack 10 comprises a first and second sub-stacks 12, 14, and humidifier 16 is joined to the first sub-stack 12. In the humidifier 16, an unused oxidant gas feed passage 90 and a used oxidant gas exhaust passage 86 are arranged close to each other. The humidifier 16 exchanges the moisture between an unused oxidant gas and a used oxidant gas, and while feeding the humidified unused oxidant gas to the second sub-stack 14, the humidifier 16 exhausts the used oxidant gas whose moisture is eliminated, from the used oxidant gas exhaust passage 86. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a sub-stack in which a plurality of electrolyte-electrode structures each having a pair of electrodes provided on both sides of an electrolyte are laminated with a separator interposed therebetween. The present invention relates to a fuel cell stack arranged in a plurality of rows.

[0002]

2. Description of the Related Art For example, a polymer electrolyte fuel cell (PEF)
C) employs an electrolyte membrane (electrolyte) composed of a polymer ion exchange membrane (cation exchange membrane). An electrolyte membrane (electrolyte) / electrode structure composed of a catalyst electrode and an anode-side electrode and a cathode-side electrode made of porous carbon, which are opposed to each other, is sandwiched between separators (bipolar plates) on both sides of the electrolyte membrane. A unit cell configured by the above is provided. Normally, a predetermined number of these unit cells are stacked to be used as a fuel cell stack.

In this type of fuel cell stack, the fuel gas supplied to the anode electrode, for example, a gas mainly containing hydrogen (hereinafter, also referred to as hydrogen-containing gas), has hydrogen ionized on the catalyst electrode, It moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electrical energy. It should be noted that the cathode side electrode has an oxidizing gas, for example,
Since oxygen-containing gas or air (hereinafter, also referred to as oxygen-containing gas) is mainly supplied, hydrogen ions, electrons and oxygen react with each other at the cathode side electrode to generate water.

By the way, in the above fuel cell stack,
When the electrolyte membrane dries, it becomes impossible to maintain high power density operation, so it is necessary to appropriately humidify the electrolyte membrane. So, for example, US Pat. No. 5,382,4
A fuel cell stack disclosed in Japanese Patent No. 78 is known.

As shown in FIG. 10, in the fuel cell stack described above, a humidifying section 4 is arranged on the upstream side of the power generation section 2, and the power generation section 2 and the humidification section 4 are arranged in the unit cell stacking direction ( It is integrally assembled in the direction of arrow X). A reaction gas supply port 6a and a reaction gas discharge port 6b are provided on the humidification unit 4 side, and the power generation unit 2 passes through the humidification unit 4 from the reaction gas supply port 6a in the fuel cell stack.
From the humidifying part 4 to the reaction gas outlet 6
A reaction gas channel 8 communicating with b is provided.

Therefore, when the reaction gas (oxidant gas or fuel gas) is supplied to the reaction gas supply port 6a, the reaction gas is humidified by the steam by flowing in the humidification section 4, and then the power generation section 2 Sent to. Furthermore, the reaction gas is exhausted from the reaction gas exhaust port 6b through the humidifying unit 4 after being consumed in the power generation unit 2. At this time, although not shown, the humidifying unit 4 is supplied with a cooling medium that has cooled the power generation unit 2, and this cooling medium is used as a steam supply source for humidifying the reaction gas.

[0007]

However, in the above-mentioned conventional technique, the cooling medium that has cooled the power generation section 2 is used for humidifying the reaction gas, and therefore it is necessary to supplement this cooling medium. Moreover, since the cooling medium is used, it is necessary to pass the cooling medium through the ion exchanger before humidifying the reaction gas. As a result, it has been pointed out that the equipment becomes complicated and large, and the cost rises.

The present invention solves this kind of problem. The generated water contained in the used reaction gas can be used as humidifying water for the unused reaction gas, and the reaction gas can be used with a simple structure. An object of the present invention is to provide a fuel cell stack capable of preventing dew condensation in the communication passage and effectively maintaining power generation performance.

[0009]

In a fuel cell stack according to claim 1 of the present invention, a sub-stack in which a plurality of electrolyte / electrode structures each having a pair of electrodes provided on both sides of an electrolyte are stacked with a separator interposed therebetween. And a plurality of the sub-stacks are arranged in a plurality of rows parallel to the stacking direction.

Further, the humidifier is provided with a humidifier for exchanging moisture between the reaction gas of at least one of the oxidant gas and the fuel gas supplied to the sub-stack and the reaction gas discharged from the sub-stack. The vessels are joined to one sub-stack.

The reaction gas communication passage for flowing at least one reaction gas to the plurality of electrolyte / electrode structures constitutes a return flow passage that passes through the plurality of sub-stacks and is folded back. In the humidifier, an unused reaction gas supply passage for supplying an unused reaction gas to the reaction gas communication passage and a used reaction gas discharge passage for discharging the used reaction gas from the reaction gas communication passage are close to each other. Is provided.

For this reason, by introducing the used reaction gas discharged from the sub-stack into the humidifier, moisture is generated between the used reaction gas and the unused reaction gas which are humidified by containing the produced water. Exchanges can be made. Therefore, it becomes possible to use the water contained in the used reaction gas as humidifying water for humidifying the unused reaction gas, effectively reducing the supplied humidifying water while reducing the amount of discharged water. can do. At that time, since water without impurities is used, an ion exchanger or the like is not required, and the configuration can be simplified.

Moreover, the water content in the used reaction gas is reduced, and the piping for returning the used reaction gas to the humidifier is simplified. This is because the pipe extending from the reaction gas outlet of the sub-stack through the inside of the humidifier is unnecessary. This prevents dew condensation from occurring in the reaction gas communication passage, introducing water into the power generation surface,
Water droplets do not stay in the reaction gas communication passage and block the reaction gas communication passage. Therefore, the reaction gas can smoothly flow to maintain good power generation performance.

Further, in the fuel cell stack according to claim 2 of the present invention, a plurality of sub-stacks are arranged in a plurality of rows along the stacking direction, and one sub-stack is
It is set shorter than the other sub-stacks in the stacking direction. The dimension in the stacking direction in which one sub-stack and the humidifier are joined is set to be the same as the dimension in the stacking direction of the other sub-stacks.

In this case, the dimension equivalent to the stacking direction is 1
This is a concept including a range in which a step is not conspicuous in the stacking direction between other sub-stacks when the individual sub-stacks and the humidifier are joined.

Therefore, when a plurality of sub-stacks arranged in a plurality of rows along the stacking direction are installed, an unnecessary gap (dead space) does not occur and the installation space of the fuel cell stack is effective. It can be narrowed down to.

Furthermore, in the fuel cell stack according to claim 3 of the present invention, a plurality of sub-stacks are arranged in a plurality of rows in parallel with the stacking direction or are connected in series in the stacking direction. A humidifier is provided for exchanging moisture between at least one reaction gas of the oxidant gas or the fuel gas supplied to the sub-stack and the reaction gas discharged from the sub-stack. Then, with the sub-stack and the humidifier joined together, the outer shape of the fuel cell stack is set to a rectangular parallelepiped shape in which irregularities are removed from the surface. In this case, the rectangular parallelepiped shape is a concept including a shape in which a conspicuous uneven portion is not visually recognized.

As a result, the outer shape of the fuel cell stack is simplified, and the degree of freedom in installing the fuel cell stack is improved. Therefore, the fuel cell stack can be easily and satisfactorily installed at an arbitrary site, and the workability of the fuel cell stack can be effectively improved.

Moreover, by configuring the sub-stacks, each sub-stack can be handled as one block, and the number of stacked layers can be reduced as compared with the configuration using unit cells. Therefore, the assembly workability of the fuel cell stack is effectively improved, and the productivity is increased.

[0020]

1 is a schematic perspective view of a fuel cell stack 10 according to a first embodiment of the present invention.
FIG. 3 is an exploded perspective view of a main part of the fuel cell stack 10.

The fuel cell stack 10 includes first and second sub-stacks 12 and 14 arranged in a plurality of rows, for example, two rows along the stacking direction (direction of arrow A). The humidifier 16 is joined to one end of the first sub-stack 12, and the end plate 17 is attached to one end of the second sub-stack 14. A connecting plate 18 is integrally fixed to the other ends of the first and second sub-stacks 12 and 14.

Dimension H of the first sub-stack 12 in the stacking direction
1 is set to be shorter than the dimension H2 of the second sub-stack 14 in the stacking direction, and the first sub-stack 1
2 and the humidifier 16 are joined together in the stacking direction (H1 + H
3) is set to be equal to the dimension H2 of the second sub-stack 14 in the stacking direction. The first and second sub-stacks 12 and 14 have the same configuration, and each have a predetermined number of unit cells 20 stacked in the direction of arrow A.

As shown in FIG. 3, the unit cell 20 comprises an electrolyte membrane (electrolyte) / electrode structure 22 and first and second separators 2 sandwiching the electrolyte membrane / electrode structure 22.
4 and 26 are provided. First and second separators 24,
26 is made of a metal thin plate or a carbon thin plate.

At one end edge portions of the electrolyte membrane / electrode structure 22 and the first and second separators 24, 26 on the long side (arrow B direction) side, they are communicated with each other in the arrow A direction, and an oxidant gas,
For example, an oxidant gas supply communication hole 30a for supplying an oxygen-containing gas, a cooling medium supply communication hole 32a for supplying a cooling medium such as pure water or ethylene glycol or oil,
And a fuel gas discharge communication hole 34b for discharging a fuel gas, for example, a hydrogen-containing gas.

Fuel gas for communicating with each other in the direction of arrow A to supply the fuel gas to the other end edges of the electrolyte membrane / electrode structure 22 and the long sides of the first and second separators 24, 26. A supply communication hole 34a, a cooling medium discharge communication hole 32b for discharging the cooling medium, and an oxidant gas discharge communication hole 30b for discharging the oxidant gas are provided.

The electrolyte membrane / electrode structure 22 includes, for example, a solid polymer electrolyte membrane 36 obtained by impregnating a thin film of perfluorosulfonic acid with water, an anode electrode 38 sandwiching the solid polymer electrolyte membrane 36, and The cathode side electrode 40 is provided. Anode side electrode 38 and cathode side electrode 4
0 is composed of a catalyst electrode and porous carbon, respectively.

On the surface 24a of the first separator 24 on the electrolyte membrane / electrode structure 22 side, for example, an oxidant gas flow channel 42 consisting of a plurality of grooves extending in the direction of arrow B is provided and the oxidation is performed. The agent gas flow path 42 communicates with the oxidant gas supply communication hole 30a and the oxidant gas discharge communication hole 30b.

The surface 26a of the second separator 26 on the electrolyte membrane / electrode structure 22 side communicates with the fuel gas supply passage 34a and the fuel gas discharge passage 34b.
4 is formed. The fuel gas flow path 44 includes a plurality of groove portions extending in the arrow B direction. Second separator 26
A cooling medium flow path 46 that communicates the cooling medium supply communication hole 32a and the cooling medium discharge communication hole 32b is formed on the surface 26b. The cooling medium flow path 46 includes a plurality of groove portions extending in the arrow B direction.

As shown in FIG. 2, the end plate 17 has a fuel gas inlet 48 communicating with the fuel gas supply passage 34a and a cooling medium inlet 50 communicating with the cooling medium supply passage 32a.

The connecting plate 18 has an oxidant gas passage 52 for communicating the oxidant gas discharge communication hole 30b of the second sub-stack 14 with the oxidant gas supply communication hole 30a of the first sub-stack 12. The second sub-stack 1
4 and the fuel gas passage 54 for communicating the fuel gas discharge communication hole 34b constituting the first sub-stack 12 with the fuel gas supply communication hole 34a constituting the first sub-stack 12, the side of the first and second sub-stacks 12, 14 The groove 18 is formed along the surface 18a. The first and second sub-stacks 12 and 14 include an oxidant gas communication passage (reaction gas communication passage) 57 and a fuel gas communication passage (reaction gas communication passage) that form a return passage.
And 59 are provided.

On the other surface 18b side of the connecting plate 18, the cooling medium supply communication holes 32a of the first and second sub-stacks 12 and 14 and the cooling medium discharge communication hole 32 are provided.
cooling medium passages 56a, 56b for communicating b with each other.
Are formed in a groove shape.

As shown in FIG. 4, the humidifier 16 has an arrow A
A plurality of sets of humidifying cells 60, which are stacked in the same direction, and end plates 62a, 6 provided at both ends of the humidifying cell 60 in the stacking direction
2b is provided. The humidification cell 60 includes a water permeable membrane 64,
Separators 66 arranged on both sides of the water permeable membrane 64,
And 68.

The separator 66 is provided with a plurality of protrusions 70 extending in the horizontal direction on the side of the water permeable membrane 64, and the separator 66 and the water permeable membrane 64 are vertically meanwhile meandering in the horizontal direction. First oxidant gas passage 72 extending in the direction
Is formed. The separator 68 is provided with a plurality of protrusions 74 that extend in the horizontal direction on the side of the water permeable membrane 64, and is vertically continuous while meandering in the horizontal direction between the separator 68 and the water permeable membrane 64. Second oxidant gas passage 7
6 is formed.

As shown in FIG. 5, in the humidifying cell 60, an unused oxidant gas discharge passage 80, a cooling medium discharge passage 82 and a used oxidant gas supply passage 84 are provided at one end side in the horizontal direction.
Is provided. At the other end of the humidification cell 60 in the horizontal direction, a used oxidant gas discharge passage 86 and a fuel gas discharge passage 88 are provided.
And a fresh oxidant gas supply passage 90 is provided.

The first oxidant gas passage 72 provided in the separator 66 connects the used oxidant gas supply passage 84 and the used oxidant gas discharge passage 86 (see FIG. 5). The second oxidant gas passage 76 provided in the separator 68 connects the unused oxidant gas supply passage 90 and the unused oxidant gas discharge passage 80.

As shown in FIG. 4, the first sub-stack 12
An oxidant gas passage 92 for communicating the unused oxidant gas discharge passage 80 with the oxidant gas supply passage 30a forming the second sub-stack 14 is formed in the end plate 62b joined to. The end plate 62b is formed with a groove portion 94 that temporarily folds up the fuel gas discharge communication hole 34b forming the first sub-stack 12 and communicates with the fuel gas discharge passage 88.

As shown in FIG. 1, the end plate 62a
A cooling medium discharge passage 82, a used oxidant gas discharge passage 86, a fuel gas discharge passage 88, and an unused oxidant gas supply passage 90 are formed in the interior. The unused oxidant gas supply passage 90 and the used oxidant gas discharge passage 86 are formed in the end plate 62a adjacent to each other.

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

First, when an oxidant gas such as an oxygen-containing gas is supplied from an unused oxidant gas supply passage 90 formed in the end plate 62a constituting the humidifier 16, the oxidant gas is supplied to the humidifier. Second oxidant gas passage 7 in 16
6 to the oxidant gas passage 92. The oxidant gas is passed through the oxidant gas passage 92 to the second sub-stack 14
Is supplied to the oxidant gas supply communication hole 30a that constitutes the (see FIG. 2).

In the second sub-stack 14, a fuel gas such as a hydrogen-containing gas is supplied from the fuel gas inlet 48 provided in the end plate 17 to the fuel gas supply communication hole 34a, and a cooling medium inlet 50 is used for cooling. Pure water or a cooling medium such as ethylene glycol or oil is supplied to the medium supply communication hole 32a. Therefore, the second sub-stack 1
In 4, the oxidizing gas, the fuel gas, and the cooling medium are supplied to the plurality of sets of unit cells 20 that are stacked in the direction of arrow A.

As shown in FIG. 3, the oxidant gas supplied to the oxidant gas supply communication hole 30 a communicating in the direction of arrow A is supplied to the plurality of oxidant gas streams provided in the first separator 24. The electrolyte membrane / electrode structure 2 is introduced into the passage 42.
It moves along the cathode side electrode 40 which comprises 2. On the other hand, the fuel gas supplied to the fuel gas supply communication hole 34 a is introduced into the plurality of fuel gas flow channels 44 provided in the second separator 26, and the anode side electrode forming the electrolyte membrane / electrode structure 22. Move along 38.

Therefore, in the electrolyte membrane / electrode structure 22,
The oxidant gas supplied to the cathode side electrode 40 and the fuel gas supplied to the anode side electrode 38 are consumed by the electrochemical reaction in the catalyst electrode, and power generation is performed.

The oxidant gas, which is partially consumed by the electrolyte membrane / electrode structure 22, is introduced from the oxidant gas flow channel 42 into the oxidant gas discharge communication hole 30b, and as shown in FIG.
Oxidant gas passage 52 provided in the connecting plate 18
Is supplied to. The oxidant gas passage 52 connects the oxidant gas discharge communication hole 30b of the second sub-stack 14 and the oxidant gas supply communication hole 30a of the first sub-stack 12 to the oxidant gas passage 52. The supplied oxidant gas is introduced into the oxidant gas supply communication hole 30a of the first sub-stack 12.

Similarly, the fuel gas partially consumed by the anode 38 forming the electrolyte membrane / electrode structure 22 is introduced into the fuel gas discharge communication hole 34b, and then the arrow A
And is discharged to the fuel gas passage 54 provided in the connecting plate 18. This fuel gas passage 54 is
It communicates with the fuel gas supply passage 34a of the first sub-stack 12, and the fuel gas is introduced into the fuel gas supply passage 34a of the first sub-stack 12.

As a result, in the first sub-stack 12,
Similar to the second sub-stack 14, the oxidant gas and the fuel gas are supplied to the cathode-side electrode 40 and the anode-side electrode 38 that form each electrolyte membrane / electrode structure 22, and are consumed by the electrochemical reaction in the catalyst electrode. Then, the power is generated.

A part of the cooling medium supplied to the cooling medium supply passage 32a of the second sub-stack 14 cools each electrolyte membrane / electrode structure 22 and the cooling medium discharge passage 3 is formed.
It is discharged to 2b. Furthermore, the cooling medium passes through the cooling medium passages 56 a and 56 b provided in the connection plate 18, and the cooling medium supply communication hole 32 of the first sub-stack 12 is provided.
a and the cooling medium discharge communication hole 32b.

The fuel gas discharged from the first sub-stack 12 is discharged from the fuel gas discharge passage 88 provided in the humidifier 16, and the cooling medium is the cooling medium provided in the humidifier 16. It is discharged from the discharge passage 82.

In this case, in the first embodiment, the used oxidant gas discharged to the oxidant gas discharge communication hole 30b of the first sub-stack 12 is used as the used oxidant gas supply passage constituting the humidifier 16. 84. As shown in FIG. 5, the used oxidant gas supplied to the used oxidant gas supply passage 84 moves along the first oxidant gas passage 72 formed in the separator 66, and the used oxidant gas is used. The gas is discharged to the gas discharge passage 86.

At this time, the second oxidant gas passage 76 is opposed to the first oxidant gas passage 72 with the water permeable membrane 64 interposed therebetween.
The unused oxidant gas is supplied (see FIG. 4). Therefore, due to the difference in the partial pressure of water vapor, water moves from the used oxidant gas in the humidified state toward the unused oxidant gas, and the water content in the used oxidant gas decreases, while in the unused oxidant gas Increase the water content.

As described above, in the first embodiment, the used oxidant gas which is consumed by the electrochemical reaction in the second sub-stack 14 and the first sub-stack 12 and contains the produced water is supplied to the humidifier 16. The water is exchanged with the unused oxidant gas. Therefore, the water contained in the used oxidant gas can be used as humidifying water for humidifying the unused oxidant gas, and the humidifying water supplied to the unused oxidant gas is used as the fuel cell stack 10. It is possible to effectively reduce the total.

Moreover, the water content in the used oxidant gas is reduced and the unused oxidant gas supply passage 9 is used.
0 and the used oxidant gas discharge passage 86 are arranged close to each other, so that the piping for returning the used oxidant gas to the humidifier 16 is simplified. As a result, dew condensation does not occur in the oxidant gas communication passage 57, water is introduced into the power generation surface, or water droplets are retained in the oxidant gas communication passage 57 and the oxidant gas communication passage 57 is retained. Will not be blocked. Therefore, it is possible to smoothly flow the oxidant gas, and it is possible to effectively maintain the power generation performance of the entire fuel cell stack 10.

The oxidant gas and the fuel gas are the second
It is supplied in series between the sub-stack 14 and the first sub-stack 12, and the first sub-stack 12 at the subsequent stage is supplied.
Is set to be smaller than the number of stacked second sub-stacks 14 in the preceding stage. Therefore, there is an advantage that the utilization rates of the oxidant gas and the fuel gas are effectively improved.

Further, in the first embodiment, as shown in FIG. 1, the first sub-stack 12 and the humidifier 16 have arrows A.
The size in the stacking direction (direction of arrow A) including the first sub-stack 12 and the humidifier 16 in the state of being joined in the direction is the stacking direction of the second sub-stack 14 (direction of arrow A).
It is set to the same size as. Therefore, the first and second sub-stacks 12, 1 arranged parallel to the stacking direction
Even when the fuel cell stack 10 and the fuel cell stack 10 are integrally installed, an unnecessary gap (dead space) does not occur, and the fuel cell stack 10
There is an advantage that the installation space of is effectively narrowed.

Furthermore, in the first embodiment, the first and second sub-stacks 12 and 14 are arranged in the horizontal direction. However, the first and second sub-stacks 12 and 14 are vertically moved as necessary. It can also be configured by stacking in the direction.

Further, the outer shape of the fuel cell stack 10 is set to a cubic shape in which irregularities are excluded from the surface (see FIG. 1). Therefore, the fuel cell stack 10 can be effectively installed in a narrow space.

Further, the fuel cell stack 10 constitutes the first and second sub-stacks 12 and 14. As a result, the first and second sub-stacks 12 and 14 can be handled as one block, and the number of stacked layers is reduced as compared with the configuration in which each unit cell is handled. For this reason,
There are advantages that the assembly workability of the fuel cell stack 10 is effectively improved and the productivity is increased.

FIG. 6 is an exploded perspective view of essential parts of a fuel cell stack 100 according to the second embodiment of the present invention. In addition,
The same components as those of the fuel cell stack 10 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The same applies to the third to fifth embodiments described below.

The fuel cell stack 100 includes a connecting plate 10 for connecting the first and second sub-stacks 12 and 14.
2 is provided. The surface 102a of the connecting plate 102 has an oxidant gas passage 10 that connects the oxidant gas supply communication holes 30a of the first and second sub-stacks 12 and 14 to each other.
4, the oxidant gas passage 106 that communicates the oxidant gas discharge communication holes 30b with each other, the fuel gas passage 108 that communicates the fuel gas supply communication holes 34a with each other, and the fuel gas discharge communication hole 3
A fuel gas passage 110 that communicates the 4b with each other is formed.

In the fuel cell stack 10, the oxidant gas and the fuel gas are supplied in series to the first and second sub-stacks 12 and 14, while the fuel cell stack 10 is
At 0, the oxidant gas and the fuel gas are supplied in parallel to the first and second sub-stacks 12 and 14.

In the second embodiment thus constructed, the unused oxidant gas supplied to the humidifier 16 is humidified by exchanging water with the used oxidant gas. , And is supplied to the oxidant gas supply communication hole 30a forming the second sub-stack 14. On the other hand, the fuel gas and the cooling medium are supplied to the fuel gas supply passage 3 of the second sub-stack 14.
4a and the cooling medium supply communication hole 32a.

In the second sub-stack 14, a part of the oxidant gas and the fuel gas supplied to the oxidant gas supply communication hole 30a and the fuel gas supply communication hole 34a constitute each electrolyte membrane / electrode structure 22. It moves along the cathode side electrode 40 and the anode side electrode 38, and is used for power generation and consumed. Then, the oxidant gas and the fuel gas flowing in the oxidant gas supply communication hole 30a and the fuel gas supply communication hole 34a pass through the oxidant gas passage 104 and the fuel gas passage 110 formed in the connection plate 102 to the first position. Oxidant gas supply communication hole 30 of one sub-stack 12
a and the fuel gas supply passage 34a.

Further, the oxidant gas and the fuel gas used for power generation are discharged through the oxidant gas passage 106 and the fuel gas passage 108 provided in the connecting plate 102 to the oxidant gas of the first sub-stack 12. The gas is discharged to the communication hole 30b and the fuel gas discharge communication hole 34b.

In this case, in the second embodiment, the used oxidizing gas used for power generation in the first and second sub-stacks 12 and 14 is sent to the humidifier 16 from the oxidizing gas discharge communication hole 30b. Moisture is exchanged with the unused oxidant gas. With this, it is possible to effectively humidify the unused oxidant gas and reduce the amount of humidification of the used oxidant gas, and it is possible to perform a good power generation function without dew condensation. The same effect as the first embodiment can be obtained.

FIG. 7 is a schematic perspective view of a fuel cell stack 130 according to the third embodiment of the present invention.

The fuel cell stack 130 comprises a first sub-stack 12 to which a humidifier 16 is joined, and second and third sub-stacks 1 arranged in parallel with the first sub-stack 12.
4, 14a. First to third sub-stack 1
2, 14 and 14a are integrally attached to the connecting plate 132, and the second and third
The end plates 134 are attached to the sub-stacks 14 and 14a.
Are integrally provided.

As described above, in the third embodiment, the fuel cell stack 130 includes the first to third sub-stacks 12,
14 and 14a are arranged side by side to form a rectangular parallelepiped outer shape as a whole, and the fuel cell stack 13
0 can be effectively miniaturized. Furthermore, by arranging the fourth sub-stack 14b or more sub-stacks as required, it becomes possible to easily cope with a case where a particularly large power is required.

FIG. 8 is a schematic plan view of a fuel cell stack 140 according to the fourth embodiment of the present invention.

In this fuel cell stack 140, the first to fourth sub-stacks 12, 14, 14a and 14b are provided, and the first and second sub-stacks 12, 14 and the third and fourth sub-stacks 14a, 14b are provided. They are arranged in the stacking direction (arrow A direction). First and second sub-stacks 12, 14 and third and fourth sub-stacks 14
A connecting plate 142 is interposed between the first and second sub-stacks 14a and 14b.
4b are connected to each other by a connecting plate 144.

In the fuel cell stack 140, a reaction gas, for example, an oxidant gas is communicated with an oxidant gas supply passage 146 and an oxidant gas discharge passage 148 provided in the vicinity of the humidifier 16, and is substantially U-shaped. An oxidant gas communication passage 150 that constitutes a return passage that is folded back in a letter shape is provided.

FIG. 9 is a schematic plan view of a fuel cell stack 160 according to the fifth embodiment of the present invention.

In this fuel cell stack 160, the first and second sub-stacks 12 and 14 are arranged in a line in the stacking direction (direction of arrow A), that is, in two lines along the direction of arrow B intersecting the stacking direction. At the same time, the humidifier 162 is joined to the end surface of the first sub-stack 12 in the direction of arrow A. The humidifier 162 has the same dimension in the direction of the arrow B as the first and second sub-stacks 12 and 14, and the fuel cell stack 160 as a whole is configured in a rectangular parallelepiped shape.

Inside the fuel cell stack 160, an oxidant gas communication passage 164 forming a substantially U-shaped return passage is provided. The oxidant gas supply passage 166 and the oxidant gas discharge passage 168, which communicate with the oxidant gas communication passage 164, are
The humidifiers 162 are provided close to each other. In addition,
In the fuel cell stack 160, the third and fourth substacks 14a, 14a, 14
It can be configured by connecting b and the like.

At this time, the fuel cell stack 160 is
To fourth sub-stacks 12, 14, 14a and 14b
With the above configuration, the first to fourth sub-stacks 12, 14, 14a and 14b can be handled as one block. Therefore, the workability of assembling the fuel cell stack 160 is effectively improved.

[0074]

In the fuel cell stack according to the present invention, by introducing the used reaction gas supplied into the plurality of sub-stacks and used for the reaction into the humidifier, the used reaction gas and the unused reaction gas are not used. Moisture can be exchanged with the reaction gas. Therefore, the water contained in the used reaction gas can be used as humidifying water for humidifying the unused reaction gas, and the supplied humidifying water can be effectively reduced.

Moreover, the water content in the used reaction gas is reduced, and the piping for returning the used reaction gas to the humidifier is simplified. As a result, it is possible to maintain good power generation performance without dew condensation occurring in the reaction gas communication passage.

[Brief description of drawings]

FIG. 1 is a schematic perspective 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 an exploded perspective view of a unit cell forming the fuel cell stack.

FIG. 4 is a partial cross-sectional explanatory view of a humidifier that constitutes the fuel cell stack.

FIG. 5 is a front explanatory view of a separator which constitutes the humidifier.

FIG. 6 is an exploded perspective view of essential parts of a fuel cell stack according to a second embodiment of the present invention.

FIG. 7 is a schematic perspective view of a fuel cell stack according to a third embodiment of the present invention.

FIG. 8 is a schematic plan view of a fuel cell stack according to a fourth embodiment of the present invention.

FIG. 9 is a schematic plan view of a fuel cell stack according to a fifth embodiment of the present invention.

FIG. 10 is a schematic explanatory diagram of a fuel cell stack according to a conventional technique.

[Explanation of symbols]

10, 100, 130, 140, 160 ... Fuel cell stack 12, 14, 14a, 14b ... Sub-stack 16, 162 ... Humidifier 17 ... End plate 18, 102, 132 ... Connection plate 20 ... Unit cell 22 ... Electrolyte membrane Electrode structure 24, 66, 6
8 ... Separator 30a ... Oxidizing gas supply communication hole 30b ... Oxidizing gas discharge communication hole 32a ... Cooling medium supply communication hole 32b ... Cooling medium discharge communication hole 34a ... Fuel gas supply communication hole 34b ... Fuel gas discharge communication hole 36 ... Solid Polymer electrolyte membrane 38 ... Anode side electrode 40 ... Cathode side electrode 42 ... Oxidizing gas flow channel 44 ... Fuel gas flow channel 46 ... Cooling medium flow channels 52, 72, 76, 92, 104, 106 ... Oxidizing gas passage 54 , 108, 110 ... Fuel gas passages 56a, 56b
Cooling medium passages 57, 150, 164 ... Oxidant gas communication passage 59 ... Fuel gas communication passage 60 ... Humidification cell 64 ... Water permeable membrane 80 ... Unused oxidant gas discharge passage 82 ... Cooling medium discharge passage 84 ... Used oxidation Agent gas supply passage 86 ... Used oxidant gas discharge passage 88 ... Fuel gas discharge passage 90 ... Unused oxidant gas supply passage 146, 166
... oxidant gas supply passages 148, 168 ... oxidant gas discharge passages

Claims (3)

[Claims] 1. A sub-stack in which a plurality of electrolyte-electrode structures having a pair of electrodes provided on both sides of an electrolyte are laminated with a separator interposed therebetween, and the plurality of sub-stacks are arranged in parallel with each other in the laminating direction. A fuel cell stack arranged in a plurality of rows, which is joined to one sub-stack, and is an unused reaction gas of at least one of an oxidant gas or a fuel gas supplied to the sub-stack, and exhausted from the sub-stack A humidifier for exchanging water with the used reaction gas, and the reaction gas communication passage for flowing at least one of the reaction gases to the plurality of electrolyte / electrode structures is a plurality of the sub-stacks. While forming a return flow path that penetrates through and returns to the humidifier, an unused reaction gas supply passage for supplying the unused reaction gas to the reaction gas communication passage and the reaction gas are provided in the humidifier. A fuel cell stack and the used reactant gas discharge passage for discharging the spent reaction gas from the communication passage, and which are located close to each other. 2. A sub-stack in which a plurality of electrolyte-electrode structures each having a pair of electrodes provided on both sides of the electrolyte are stacked with a separator interposed therebetween, and the plurality of sub-stacks are plural in the stacking direction. A fuel cell stack arranged in rows, wherein an unused reaction gas of at least one of an oxidant gas or a fuel gas supplied to the sub-stack and a used reaction gas exhausted from the sub-stack. A humidifier for exchanging moisture is provided, the humidifier is joined to one sub-stack in the stacking direction, and the dimension in the stacking direction including one sub-stack and the humidifier is different from that of the other sub-stack. A fuel cell stack, which is set to have a size equal to the dimension of the sub-stack in the stacking direction. 3. A sub-stack in which a plurality of electrolyte-electrode structures having a pair of electrodes provided on both sides of an electrolyte are laminated with a separator interposed therebetween, and the plurality of sub-stacks are arranged in parallel with each other in the laminating direction. A fuel cell stack arranged in a plurality of rows or connected in series in the stacking direction, wherein an unused reaction gas of at least one of an oxidant gas and a fuel gas supplied to the sub-stack, and the sub-stack. The fuel cell stack has a humidifier for exchanging water with the used reaction gas discharged from the sub-stack and the humidifier. A fuel cell stack having a rectangular parallelepiped shape.