JP2003157865A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively check generation of dew condensation while reducing a pressure loss, and to smoothly drain out generated water and condensed water. SOLUTION: An oxidizer gas passage 62 and a fuel gas passage 64 are provided in a unit fuel cell 30. An oxidizer gas discharging communicating hole 54 and a fuel cell gas discharging communicating hole 50 to compose the oxidizer gas passage 62 and the fuel gas passage 64 and to discharge oxidizer gas and fuel gas which have passed through an electrode reaction surface are provided between cathode side electrodes 40a, 40b split into two and between anode side electrodes 42a, 42b split into two, respectively.

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 electrolyte / electrode structures each having a pair of electrodes arranged on both sides of an electrolyte are stacked with a separator interposed therebetween.

[0002]

2. Description of the Related Art For example, a polymer electrolyte fuel cell has an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode are provided on opposite sides of an electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane). It is configured by sandwiching the body with a separator.

This type of fuel cell is usually used as a fuel cell stack by stacking a predetermined number of electrolytes (electrolyte membranes) / electrode structures and separators. In the fuel cell stack, the fuel gas supplied to the anode electrode, for example, the hydrogen-containing gas is hydrogen ionized on the catalyst electrode and moves to the cathode electrode side through the appropriately humidified electrolyte membrane, The electrons generated during the movement are taken out to an external circuit and used as direct current electric energy. The cathode side electrode has an oxidant gas,
For example, since oxygen-containing gas such as air is supplied, the hydrogen ions, the electrons, and the oxygen gas react with each other at the cathode side electrode to generate water.

By the way, in the above fuel cell stack,
Generally, a reaction gas supply communication hole for supplying and discharging a reaction gas such as a fuel gas or an oxidant gas and a reaction gas discharge communication hole are provided at the edge of the separator so as to penetrate in the stacking direction. However, since the reaction gas exhaust communication hole is provided at the edge portion of the separator, that is, at the end portion of the fuel cell, the humidified exhaust gas causes a temperature decrease due to heat dissipation, and particularly the fuel cell It has been pointed out that dew condensation easily occurs near the reaction gas outlet.

Therefore, for example, US Pat. No. 5,484,
As disclosed in Japanese Patent No. 666, there is known a fuel cell stack provided with a reaction gas supply communication hole and a reaction gas discharge communication hole penetrating the electrolyte / electrode structure. Specifically, as shown in FIG. 10, the fuel cell stack 1
Includes a fuel cell assembly 2 stacked in the direction of arrow A. The fuel cell assembly 2 includes an electrolyte membrane / electrode structure 3 and a pair of flow path plates sandwiching the electrolyte membrane / electrode structure 3. 4 and 5 are provided.

First and second end plates 6 and 7 are arranged at both ends of the fuel cell assembly 2 in the stacking direction, and the fuel cell assembly 2 is located between the first and second end plates 6 and 7. 4 tie rods 8
It is clamped and held integrally via.

The first end plate 6 is provided with a fuel gas supply manifold 9a, a cooling medium supply manifold 10a and an oxidant gas supply manifold 11a, while the second end plate 7 is provided with a fuel gas discharge manifold 9b and a cooling medium. An exhaust manifold 10b and an oxidant gas exhaust manifold 11b are provided.

The horizontal direction of the fuel cell assembly 2 (arrow C
Direction) to one end side, the fuel gas supply communication hole 12a, the cooling medium supply communication hole 13a, and the oxidant gas supply communication are communicated in the up-down direction (direction of arrow B) through the opening communicating with the stacking direction (direction of arrow A). The hole 14a is provided. At the other end of the fuel cell assembly 2 in the horizontal direction, the oxidant gas discharge communication hole 14b and the cooling medium discharge communication hole 13 are arranged in the vertical direction.
b and a fuel gas discharge communication hole 12b are provided.

In such a structure, the fuel gas, the cooling medium and the oxidant gas are introduced into the fuel gas supply manifold 9a, the cooling medium supply manifold 10a and the oxidant gas supply manifold 11a, respectively. Therefore, the fuel gas, the cooling medium, and the oxidant gas are supplied to the fuel gas supply communication hole 12a, the cooling medium supply communication hole 13a, and the oxidant gas supply communication hole 14a formed in the fuel cell assembly 2.

The fuel gas and the oxidant gas are the electrolyte membrane and
After passing through the electrode reaction surface through the fuel gas flow path and the oxidant gas flow path (not shown) formed through both surfaces of the electrode structure 3 and the flow path plates 4 and 5, the fuel gas discharge communication hole 12b is formed. And is discharged to the oxidizing gas discharge communication hole 14b. On the other hand, the cooling medium is discharged to the cooling medium discharge communication hole 13b after cooling the electrolyte membrane / electrode structure 3.

[0011]

However, in the above-mentioned prior art, there is a possibility that dew condensation may occur on the humidified oxidant gas discharged to the oxidant gas discharge communication hole 14b, and the generated water and dew condensation may occur. Water is not drained well,
There is a problem that the smooth flow of the oxidant gas is blocked and the power generation performance deteriorates.

Further, one electrode having a relatively large size is provided on each of both surfaces of the electrolyte membrane / electrode structure 3. As a result, it has been pointed out that the pressure loss of the reaction gas and the cooling medium per unit fuel cell is likely to be large, the electrode performance is deteriorated, and the load of the pump for the cooling medium is large.

The present invention solves this kind of problem, and aims at reducing the pressure loss, effectively preventing the generation of dew condensation, and capable of smoothly discharging generated water or dew condensation water. Intended to provide a stack.

[0014]

In a fuel cell stack according to claim 1 of the present invention, an electrode constituting an electrolyte / electrode structure is divided into a plurality of electrodes, and at least one of a fuel gas and an oxidant gas is used. The reaction gas flow passage through which the reaction gas flows has a reaction gas supply communication hole provided on the outer peripheral end side of the separator and a reaction gas discharge communication hole provided between the divided electrodes.

Therefore, the reaction gas supplied to the reaction gas supply communication hole passes through the reaction surface of the electrode and is discharged to the reaction gas discharge communication hole. At that time, the reaction gas discharge communication hole is provided between the divided electrodes. For this reason, it is possible to effectively prevent a temperature drop due to heat dissipation of the reaction gas discharged to the reaction gas discharge communication hole, and it is possible to effectively reduce dew condensation and accumulated water (generated water or dew condensation water).

Moreover, since the electrode is divided into a plurality of pieces along the surface direction of the separator, the flow path length of the reaction gas is effectively shortened. Thereby, the pressure loss per unit fuel cell can be reduced. Furthermore, since the flow path length of the cooling medium is shortened, it is possible to reduce the pressure loss of the cooling medium and reduce the load on the cooling medium pump.

Further, in the fuel cell stack according to the second aspect of the present invention, the cooling medium discharge communication hole forming the cooling medium flow path is provided close to the reaction gas discharge communication hole.
Therefore, the humidifying gas (reaction gas containing a large amount of water) discharged to the reaction gas discharge communication hole is heated by the cooling medium discharged to the cooling medium discharge communication hole on the high temperature side, and the temperature is lowered. It becomes possible to effectively reduce the occurrence of dew condensation.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic exploded perspective view of a main part of a fuel cell stack 20 according to a first embodiment of the present invention.

The fuel cell stack 20 comprises a first sub-stack 22 and a second sub-stack 22 arranged in the stacking direction (direction of arrow A).
A sub-stack 24 is provided, and an intermediate plate 26 is interposed between the first and second sub-stacks 22 and 24.
The fuel cell stack 20 is not limited to the first and second sub-stacks 22 and 24, and if necessary, three or more sub-stacks (not shown) may be provided between the intermediate plates 26. Can be laminated in the direction of the arrow A.

First and second sub-stacks 22, 24
Are similarly configured, and each is configured by stacking a predetermined number of unit fuel cell units 30 in the direction of arrow A. As shown in FIG. 2, the unit fuel cell unit 30 includes an electrolyte membrane (electrolyte) / electrode structure 32, the electrolyte membrane
First and second separators 3 sandwiching the electrode structure 32
4, 36.

The electrolyte membrane / electrode structure 32 has a solid polymer electrolyte membrane (electrolyte) 38, and cathode-side electrodes 40a, 40b and anode-side electrodes 42a, 42b which are arranged so as to sandwich the electrolyte membrane 38. . Cathode side electrode 4
0a and 40b are arranged on the first separator 34 side and are divided into two along the surface direction of the first separator 34. Similarly, the anode-side electrodes 42a and 42b are arranged on the second separator 36 side and are divided along the surface direction of the second separator 36.

The cathode-side electrodes 40a and 40b and the anode-side electrodes 42a and 42b are each composed of a catalyst electrode and porous carbon, and also have first and second electrodes.
The separators 34 and 36 are made of metal thin plates or carbon thin plates.

On the upper side of the electrolyte membrane / electrode structure 32 and the first and second separators 34, 36, a pair of oxidant gas supply passages (in the vicinity of both end edges in the long side direction (arrow C direction)) are provided. A reaction gas supply communication hole) 44a is provided, and a pair of cooling medium supply communication holes 46a is provided inside the oxidizing gas supply communication hole 44a. A single fuel gas supply communication hole (reaction gas supply communication hole) 48a is provided between the cooling medium supply communication holes 46a.

On the lower side of the electrolyte membrane / electrode structure 32 and the first and second separators 34, 36, a pair of oxidant gas supply communication holes (reaction gas supply communication holes) are provided in the vicinity of both ends in the long side direction. ) 44b is provided, and a pair of cooling medium supply communication holes 4 are provided inside the oxidant gas supply communication hole 44b.
6b is provided. A single fuel gas supply communication hole (reaction gas supply communication hole) is provided between the cooling medium supply communication holes 46b.
48b is provided.

The short side direction of the electrolyte membrane / electrode structure 32 and the first and second separators 34, 36 (direction of arrow B)
A pair of fuel gas discharge communication holes (reaction gas discharge communication holes) 50 are provided in the central portion in the vicinity of both ends in the long side direction,
A pair of cooling medium discharge communication holes 52 is provided inside the fuel gas discharge communication hole 50. A single oxidant gas discharge communication hole (reaction gas discharge communication hole) 54 is provided between the cooling medium discharge communication holes 52.

An oxidant gas (reaction gas) such as an oxygen-containing gas flows in the oxidant gas supply communication holes 44a and 44b in the stacking direction (direction of arrow A), and the oxidant gas discharge communication hole 54 has The oxidant gas that has passed through the electrode reaction surface flows in the stacking direction. Cooling medium supply communication hole 46a,
A cooling medium such as pure water or ethylene glycol or oil is supplied to 46b, while a cooling medium which has a high temperature by cooling the electrode reaction surface flows into the cooling medium discharge communication hole 52. A fuel gas (reaction gas) such as a hydrogen-containing gas flows through the fuel gas supply communication holes 48a and 48b,
The fuel gas passing through the electrode reaction surface flows into the fuel gas discharge communication hole 50.

The fuel gas discharge communication hole 50, the oxidant gas discharge communication hole 54 and the cooling medium discharge communication hole 52 are vertically arranged in two.
It is set correspondingly between the divided cathode side electrodes 40a and 40b and between the divided anode side electrodes 42a and 42b.

The cathode side electrode 40 of the first separator 34
A plurality of independent oxidant gas flow channels 56a and 56b, which communicate with the oxidant gas supply communication holes 44a and 44b, are provided on the surface 34a facing the a and 40b. The downstream side of the oxidizing gas flow channels 56a and 56b communicates with the oxidizing gas discharge communication hole 54.

The anode 42 of the second separator 36
As shown in FIG. 3, a plurality of fuel gas flow passage grooves 58a communicating with the fuel gas supply communication hole 48a and the fuel gas discharge communication hole 50 are provided on the upper side of the surface 36a facing the a and 42b. A plurality of fuel gas passage grooves 58b communicating with the fuel gas supply passage 48b and the fuel gas discharge passage 50 are provided on the lower side of the surface 36a.

On the upper side of the surface 36b opposite to the surface 36a of the second separator 36, as shown in FIG. 2, a plurality of cooling mediums communicating with the cooling medium supply communication hole 46a and the cooling medium discharge communication hole 52 are provided. A channel groove 60a is provided. A plurality of cooling medium flow passage grooves 60b communicating with the cooling medium supply communication hole 46b and the cooling medium discharge communication hole 52 are provided on the lower side of the surface 36b.

Oxidant gas supply communication holes 44a, 44b, oxidant gas discharge communication hole 54 and oxidant gas passage groove 56.
Oxidizing gas flow path (reaction gas flow path) 62 by a and 56b
Is configured. Similarly, the fuel gas supply communication holes 48a, 4
8b, fuel gas discharge communication hole 50, and fuel gas passage groove 5
Fuel gas passage (reaction gas passage) 64 by 8a and 58b
Is configured.

As shown in FIG. 1, the intermediate plate 26 is
An oxidant gas discharge communication hole 54 and an oxidant gas supply communication hole 44 are formed on one surface 26 a facing the first sub-stack 22.
oxidant gas passages 70a, 70b communicating with a, 44b
Is provided. As shown in FIG. 4, on the surface 26b of the intermediate plate 26 facing the second sub-stack 24, the fuel gas discharge communication hole 50 and the fuel gas supply communication holes 48a, 48b are formed.
Fuel gas passages 72a, 72b communicating with and are provided.

Although not shown, the joint surface between the intermediate plate 26 and the first and second sub-stacks 22 and 24 is not shown.
A seal member is interposed. By the seal member on the side of the first sub-stack 22, the oxidant gas supply communication holes 44a and 44b of the intermediate plate 26 and the fuel gas supply communication hole 48 are formed.
a, 48b, the oxidant gas supply communication holes 44a, 44b of the first sub-stack 22, and the fuel gas supply communication hole 48.
a and 48b are cut off. The seal member on the side of the second sub-stack 24 blocks the communication between the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 between the intermediate plate 26 and the second sub-stack 24.

The operation of the fuel cell stack 20 according to the first embodiment configured as described above will be described below.

As shown in FIG. 1, an oxygen-containing gas such as air (hereinafter simply referred to as "air") is supplied as an oxidant gas to the oxidant gas supply communication holes 44a and 44b, and the fuel gas supply communication hole is formed. A hydrogen-containing gas is supplied as a fuel gas to 48a and 48b. Further, a cooling medium is supplied to the cooling medium supply communication holes 46a and 46b.
Further, the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 are supplied with a low-humidification unused oxidant gas and a low-humidification unused fuel gas, respectively.

Therefore, in the first sub-stack 22, a plurality of sets of unit fuel cells 3 stacked in the direction of arrow A are stacked.
0, the oxidant gas, the fuel gas and the cooling medium are supplied (see FIG. 1).

The oxidant gas supplied to the oxidant gas supply communication holes 44a and 44b communicating in the direction of arrow A is as shown in FIG.
As shown in FIG. 5, the gas is introduced into the oxidant gas flow channel grooves 56a and 56b provided on the surface 34a of the first separator 34,
Cathode side electrode 4 constituting the electrolyte membrane / electrode structure 32
It moves in the gravity direction and the anti-gravity direction along 0a and 40b.

On the other hand, the fuel gas supply passages 48a, 48b
Is supplied to the surface 36 of the second separator 36.
The gas is introduced into the fuel gas flow channels 58a and 58b provided in a, and moves along the anode-side electrodes 42a and 42b forming the electrolyte membrane / electrode structure 32. Therefore, in the electrolyte membrane / electrode structure 32, the cathode side electrodes 40 a, 4
0b and the oxidant gas supplied to the anode side electrode 42a,
The fuel gas supplied to 42b is consumed by an electrochemical reaction in the catalyst electrode, and power generation is performed.

Further, the cooling medium supply communication holes 46a, 46b.
The cooling medium supplied to the surface 36 of the second separator 36.
After moving along the cooling medium flow channels 60a and 60b provided on the b side to cool the electrolyte membrane / electrode structure 32, the cooling medium is discharged to the cooling medium discharge communication hole 52.

As described above, the oxidant gas and the fuel gas consumed in each unit fuel cell 30 are discharged into the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50, respectively, and the first sub-stack 22 is discharged. To the intermediate plate 26 arranged on the downstream side of.

As shown in FIG. 1, the intermediate plate 26 is provided with oxidant gas passages 70a and 70b on one surface 26a, and the used oxidant gas discharged to the oxidant gas discharge communication hole 54 is used. And the low-humidity unused oxidant gas introduced into the oxidant gas discharge communication hole 50 are mixed and introduced into the oxidant gas passages 70a and 70b. As a result, the mixed gas of the used oxidant gas in the humidified state and the unused oxidant gas in the low-humidified state passes through the oxidant gas passages 70a and 70b, and the oxidant gas supply communication hole 44a of the second sub-stack 24, 44b.

On the other hand, the other surface 26b of the intermediate plate 26
Are provided with fuel gas passages 72a and 72b (see FIG. 4). In the fuel gas passages 72a and 72b,
Through the fuel gas discharge communication hole 50, a low concentration used fuel gas and a low humidified unused fuel gas are introduced in a mixed state. Therefore, the mixed gas of the low-concentration fuel gas and the low-humidified unused fuel gas is supplied to the fuel gas supply communication holes 48a and 48b of the second sub-stack 24.

In the second sub-stack 24, as in the case of the first sub-stack 22 described above, the oxidizing gas supply communication hole 44 is formed.
The oxidant gas supplied to a and 44b is supplied to the cathode-side electrodes 40a and 40b forming the electrolyte membrane / electrode structure 32, while the fuel gas supplied to the fuel gas supply communication holes 48a and 48b is The electrolyte membrane / electrode structure 32
Is supplied to the anode-side electrodes 42a and 42b that constitute the. Therefore, power is generated in the electrolyte membrane / electrode structure 32, and the consumed oxidant gas and fuel gas are
Oxidant gas discharge communication hole 54 and fuel gas discharge communication hole 5
It is discharged to the outside through 0.

In this case, in the first embodiment, the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 are respectively divided into two between the cathode side electrodes 40a and 40b and between the anode side electrodes 42a and 42b. Correspondingly provided. Therefore, compared with the conventional structure in which the reaction gas discharge communication passage is provided outside the electrode, heat dissipation can be effectively prevented, and dew condensation in the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 can be achieved. And accumulated water (generated water and condensed water)
Is effectively reduced.

Moreover, the cathode-side electrodes 40a and 40b and the anode-side electrodes 42a and 42, which are divided into two parts, respectively.
b is used, the oxidizing gas passage grooves 56a and 56b are used.
Also, the flow path lengths of the fuel gas flow path grooves 58a and 58b are shortened, and the pressure loss per unit fuel cell unit 30 can be effectively reduced. Similarly, the cooling medium channel 6
The flow passage lengths of 0a and 60b are shortened, the pressure loss of the cooling medium can be reduced, and the load of the cooling medium pump (not shown) can be effectively reduced.

Further, two oxidant gas supply communication holes 44a, 44b and two fuel gas supply communication holes 48 are provided, respectively.
a, 48b and two fuel gas discharge communication holes 50 are adopted. As a result, the distributability of the oxidant gas and the fuel gas within the electrode reaction surface is improved, and the variation in gas distribution can be suppressed.

Further, in the first embodiment, the cooling medium discharge communication hole 52 is provided close to the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50. The cooling medium which has become high temperature by cooling the electrolyte membrane / electrode structure 32 is discharged to the cooling medium discharge communication hole 52. Therefore, the oxidant gas and the low-concentration fuel gas containing a large amount of water, which are discharged to the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50, are heated through the high-temperature cooling medium to form dew condensation water. There is an advantage that it can be effectively reduced.

Furthermore, the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 are supplied with a low-humidification unused oxidant gas and a low-humidification unused fuel gas. Therefore, as shown in FIG. 5, in the vicinity of the gas outlet of each unit fuel cell 30, the oxidant gas flow channels 56a,
6b and the fuel gas flow channels 58a, 58b and the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 through a dynamic pressure difference (gas pressure difference) between the accumulated water (generated water and condensed water). Can be forcibly removed. Moreover,
The unused humidifier gas with low humidification and the unused fuel gas with low humidity are mixed with the discharged oxidizing gas and fuel gas with high humidity, so that the relative humidity is lowered and the occurrence of dew condensation is effectively prevented. You can

Further, the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 are heated by the cooling medium discharge communication hole 52, and the newly introduced unused oxidant gas and unused fuel gas, respectively. Can be heated to reduce condensation water. This makes it possible to increase the humidification amounts of the oxidant gas and the fuel gas supplied to the second sub-stack 24 in the subsequent stage, and efficiently supply the humidified oxidant gas and the high-concentration fuel gas to the second sub-stack 24. Can be reliably supplied to.

FIG. 6 is an explanatory view of a reaction gas flow in the fuel cell stack 100 according to the second embodiment of the present invention.
The same components as those of the fuel cell stack 20 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In addition, the third and fourth described below
The same applies to the embodiment.

The fuel cell stack 100 includes first and second sub-stacks 22, 24 and an intermediate plate 102 interposed between the first and second sub-stacks 22, 24.
With.

The intermediate plate 102 is composed of one or more plate members. This intermediate plate 102 has a low-humidity unused oxidant gas and a low-humidity unused oxidant gas exhaust communication hole 54 and a fuel gas exhaust communication hole 50 provided in the second sub-stack 24 in the subsequent stage. An additional oxidant gas passage 104 and an additional fuel gas passage 106 are provided for directly supplying the fuel gas.

In the second embodiment constructed as described above, the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 forming the second sub-stack 24 are respectively used with a low-humidity unused oxidant gas and Fresh fuel gas with low humidification is introduced. Therefore, it is possible to adjust the humidification amount and the temperature of the spent oxidant and the spent fuel gas discharged into the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50.

Therefore, in the second embodiment, in the first and second sub-stacks 22 and 24, it is possible to effectively generate the condensed water and the generated water in the oxidizing gas discharge communication hole 54 and the fuel gas discharge communication hole 50. As a result, the oxidant gas and the fuel gas can be smoothly flowed in the first and second sub-stacks 22 and 24, and the power generation performance of the entire fuel cell stack 100 can be effectively maintained. The same effect as that of the above embodiment can be obtained.

FIG. 7 is a schematic exploded perspective view of a fuel cell stack 120 according to the third embodiment of the present invention.

The fuel cell stack 120 is vertically longer than the fuel cell stack 20 according to the first embodiment, and includes first and second sub-stacks 122 and 124 arranged in the direction of arrow A. An intermediate plate 126 is interposed between the first and second sub-stacks 122 and 124. First and second sub-stacks 122, 124
A predetermined number of unit fuel cells 128, which constitute the
Is the electrolyte membrane / electrode structure 130 as shown in FIG.
And first and second separators 132 and 134 sandwiching the electrolyte membrane / electrode structure 130.

The long side direction of the electrolyte membrane / electrode structure 130 and the first and second separators 132 and 134 (arrow C).
A pair of oxidant gas supply communication holes 44a, a pair of cooling medium supply communication holes 46a, and a single fuel gas supply communication hole 48a are provided on one end side in the vertical direction (direction of arrow B).

On the other end side of the electrolyte membrane / electrode structure 130 and the first and second separators 132, 134 in the long side direction, a pair of oxidant gas supply communication holes 44 is provided along the vertical direction.
b, a pair of cooling medium supply communication holes 46b and a single fuel gas supply communication hole 48b are provided, and a pair of fuel gas discharge communication holes 50 and a pair of fuel gas discharge communication holes 50 are provided along the vertical direction at the central portion side in the long side direction. A cooling medium discharge communication hole 52 and a single oxidant gas discharge communication hole 54 are provided.

In the electrolyte membrane / electrode assembly 130, the cathode side electrodes 40a, 40b and the anode side electrode 42a,
42b is divided into two in the horizontal direction (direction of arrow C).

In the third embodiment having such a configuration, the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50 are provided between the cathode side electrodes 40a and 40b and between the anode side electrodes 42a and 42b. At the same time, a cooling medium discharge communication hole 52 is provided close to the oxidant discharge communication hole 54 and the fuel gas discharge communication hole 50. Furthermore, a low-humidification unused oxidant gas and a low-humidification unused fuel gas are supplied to the oxidant gas discharge communication hole 54 and the fuel gas discharge communication hole 50.

As a result, the condensed water and the generated water do not stay in the oxidizing gas discharge communication hole 54 and the fuel gas discharge communication hole 50, and the pressure loss can be easily reduced. The same effect as can be obtained. In addition, the cathode side electrodes 40a and 40b and the anode side electrode 42
Since a and 42b are divided into two in the horizontal direction (direction of arrow C), the influence in the direction of gravity is small, and the cathode-side electrodes 40a and 40b and the anode-side electrode 42a,
The power generation characteristics of 42b are the same.

In the first to third embodiments, the cathode-side electrodes 40a and 40b and the anode-side electrodes 42a and 42b divided into two are used, but the present invention is not limited to this, and three electrodes are used. It is also possible to divide it or to divide it into four or more.

FIG. 9 is an exploded perspective view showing a main part of a unit fuel cell 140 constituting a fuel cell stack according to a fourth embodiment of the present invention.

The unit fuel cell unit 140 comprises an electrolyte membrane / electrode structure 142, and first and second separators 144, 146 sandwiching the electrolyte membrane / electrode structure 142. The electrolyte membrane / electrode structure 142 is made up of the electrolyte membrane 38.
Cathode side electrode 40, which is divided into two on each side
a and 40b are provided, and the anode side electrode 42 is divided into two parts on the other surface of the electrolyte membrane 38.
a and 42b are provided. Therefore, in the fourth embodiment, the unit fuel cell unit 140 in which the electrode is divided into four can be configured.

[0065]

In the fuel cell stack according to the present invention, the electrodes constituting the electrolyte membrane / electrode structure are divided into a plurality of parts, and the reaction gas exhaust communication hole is provided between the electrodes. For this reason, it becomes possible to effectively keep the temperature of the reaction gas discharge communication hole, prevent heat dissipation, and effectively reduce condensation and accumulated water. Moreover, since the electrode is divided into a plurality of parts along the surface direction of the separator, the flow path length of the reaction gas can be effectively shortened, and the pressure loss can be reduced.

[Brief description of drawings]

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

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

FIG. 3 is a front view of the other surface of a second separator that constitutes the unit fuel cell unit.

FIG. 4 is a front view of the other surface of the intermediate plate forming the fuel cell stack.

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

FIG. 6 is a reaction gas flow explanatory diagram in the fuel cell stack according to the second embodiment of the present invention.

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

FIG. 8 is an exploded perspective view of a main part of a unit fuel battery cell that constitutes the fuel cell stack.

FIG. 9 is an exploded perspective view of a main part of a unit fuel cell unit constituting a fuel cell stack according to a fourth embodiment of the present invention.

FIG. 10 is a partially cutaway perspective view of a conventional fuel cell stack.

[Explanation of symbols]

20, 100, 120 ... Fuel cell stacks 22, 24, 122, 124 ... Sub-stacks 26, 102, 126 ... Intermediate plates 30, 128, 140 ... Unit fuel potential cells 32, 130, 142 ... Electrolyte membrane / electrode structure 34 , 36, 132, 134, 144, 146 ... Separator 38 ... Electrolyte membranes 40a, 40b ... Cathode side electrodes 42a, 42b ... Anode side electrodes 44a, 44b ... Oxidizing gas supply communication holes 46a, 46b ... Cooling medium supply communication hole 48a , 48b ... Fuel gas supply communication hole 50 ... Fuel gas discharge communication hole 52 ... Cooling medium discharge communication hole 54 ... Oxidant gas discharge communication hole 56a, 56b ... Oxidant gas flow channel grooves 58a, 58b ... Fuel gas flow channel groove 60a , 60b ... Cooling medium channel 62 ... Oxidant gas channel 64 ... Fuel gas channel 70a, 70b ... Oxidant gas channel 72 a, 72b ... Fuel gas passage 104 ... Additional oxidant gas passage 106 ... Additional fuel gas passage

Claims (2)

[Claims] 1. A fuel cell stack in which a plurality of electrolyte / electrode structures in which a pair of electrodes are disposed on both sides of an electrolyte are stacked with a separator interposed therebetween, and the separator penetrates in the stacking direction to form a fuel gas. Or a reaction gas flow path for flowing a reaction gas that is at least one of oxidant gas, the electrode is divided into a plurality along the surface direction of the separator, the reaction gas flow path of the separator A reaction gas supply communication hole provided on the outer peripheral end side for supplying the reaction gas, and a reaction gas discharge communication hole provided between the divided electrodes for discharging the reaction gas passing through the electrode reaction surface, A fuel cell stack comprising: 2. The fuel cell stack according to claim 1, further comprising a cooling medium passage that penetrates through the separator in a stacking direction and flows a cooling medium, the cooling medium passage being provided on an outer peripheral end side of the separator. A cooling medium supply communication hole for supplying the cooling medium, and a cooling medium discharge communication hole provided near the reaction gas discharge communication hole for discharging the cooling medium that has cooled the electrode reaction surface. Is a fuel cell stack.