JP2003323905A - Solid polymer fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent retention of water and to uniformize current density with a simple structure. <P>SOLUTION: A fuel cell 10 comprises an electrolyte membrane/electrode structure 14, and first and second separators 16, 18 sandwiching the structure 14. The first separator 16 has a surface 16a facing toward a cathode-side electrode 36. First and second oxidant gas flow passage blocks 38a, 38b are independently provided at the upper part and the lower part of the surface 16a, respectively. Both ends of the blocks 38a, 38b are communicated with first and second oxidant gas supplying communication holes 20a, 24a, and first and second oxidant gas discharging communication holes 20b, 24b. The blocks 38a, 38b have linear flow passages, of which flow directions are set to be opposite. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrolyte fuel cell provided with an electrolyte / electrode assembly having electrodes on both sides of an electrolyte and a pair of separators sandwiching the electrolyte / electrode assembly. .

[0002]

2. Description of the Related Art Generally, a polymer electrolyte fuel cell is an electrolyte membrane in which an anode-side electrode and a cathode-side electrode are respectively provided on both sides of an electrolyte membrane composed of a polymer ion exchange membrane (cation exchange membrane). -It is configured by sandwiching the electrode structure with separators. 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 this type of fuel cell, the fuel gas supplied to the anode electrode, for example, a gas containing mainly hydrogen (hereinafter, also referred to as hydrogen-containing gas) is ionized into hydrogen on the electrode catalyst to form an electrolyte. It moves to the cathode side electrode side through the film. Electrons generated during that time are taken out to an external circuit and used as direct current electrical energy. In addition,
Since the cathode side electrode is supplied with an oxidant gas, for example, a gas mainly containing oxygen or air (hereinafter, also referred to as oxygen containing gas), hydrogen ions, electrons and oxygen are generated in the cathode side electrode. React to produce water.

In the above fuel cell, a fuel gas passage (reaction gas passage) for flowing a fuel gas is provided in the surface of the separator so as to face the anode electrode, and an oxidant gas faces the cathode electrode. And an oxidant gas flow channel (reaction gas flow channel) for flowing the gas. Also, between the separators,
A cooling medium flow path for flowing a cooling medium is provided along the surface direction of the separator as needed.

In this case, in order to maintain a desired power generation function, a fuel gas and an oxidant gas are supplied over the entire power generation surface (reaction surface) of the anode electrode and the cathode electrode within the surface of each separator. There is a need. Therefore, the separator is provided with a long fuel gas channel and an oxidant gas channel in a meandering manner, and is provided with a fuel gas channel and an oxidant gas channel consisting of a plurality of channel grooves. I am.

However, as described above, if the fuel gas flow path and the oxidant gas flow path are long in the plane of the separator, the fuel gas and the oxidant gas can be uniformly supplied into the power generation surface. If it is not possible, the power generation efficiency may decrease. Further, the generated water may move in the gas flow direction and stay in the downstream side of the fuel gas passage or the oxidant gas passage, and the flow of the fuel gas or the oxidant gas may be blocked. Furthermore,
If the fuel gas flow path or the oxidant gas flow path has a folded portion or a change in the number of flow paths, it is easily affected by the occurrence of turbulence, fluctuations in flow speed, and accumulated water, which causes deterioration of the power generation environment. There is.

Therefore, in order to solve this kind of problem,
For example, a current collector plate for a polymer electrolyte fuel cell disclosed in JP 2001-250568 A is known. In this conventional technique, as shown in FIG. 11, fuel gas passages 2a and 2b which are vertically divided into two are provided on one laminated surface facing a cathode (not shown) of the current collector plate 1, and Similarly, an oxidant gas passage (not shown) which is vertically divided into two is formed on the other laminated surface of the current collector plate 1 facing the anode (not shown).

A fuel gas passage 2 is provided at one end of the current collector plate 1.
First and second intake holes 3 for supplying fuel gas to a and 2b
a, 3b, and first and second exhaust holes 4c, 4d for discharging the oxidant gas from an oxidant gas passage (not shown),
A water supply hole 5a is formed. At the other end of the collector plate 1, first and second exhaust holes 3c and 3d for discharging the fuel gas from the fuel gas passages 2a and 2b, and an oxidant gas are supplied to an oxidant gas passage (not shown). First and second intake holes 4a and 4b for drainage and a drain hole 5b are formed.

The fuel gas passages 2a and 2b have a plurality of parallel grooves 6a and 6b extending linearly in the horizontal direction from the first and second intake holes 3a and 3b, and the first and second exhaust holes 3.
A predetermined flow path groove is formed by the lattice grooves 7a and 7b adjacent to the c and 3d sides.

As described above, the lattice grooves 7 are provided so that the degree of communication is increased in the downstream side portions of the fuel gas passages 2a, 2b.
By providing a and 7b, it is possible to suppress clogging due to liquefied water. Further, the straight parallel grooves 6a,
By providing 6b, it is possible to suppress a decrease in water content on the upstream side of the fuel gas passages 2a, 2b, maintain good power generation efficiency, and reduce pressure loss.

[0011]

However, in the above-mentioned prior art, the divided fuel gas passages 2a, 2b are provided.
The flow direction of the fuel gas is set to be the same direction (direction of arrow X) and horizontal. For this reason, the generated water tends to stay on the downstream side in the flow direction, the reaction distribution in the power generation surface cannot be made uniform, and the current density tends to concentrate partially (especially on the upstream side in the flow direction). A problem has been pointed out. As a result, there is a problem in that efficient power generation performance cannot be maintained.

The present invention solves this kind of problem, and with a simple structure, it is possible to uniformly supply a reaction gas to the electrolyte / electrode structure and prevent the generation of stagnant water, and further, to prevent the generation of current. An object of the present invention is to provide a polymer electrolyte fuel cell capable of uniforming the density.

[0013]

In the polymer electrolyte fuel cell according to claim 1 of the present invention, a reaction of an oxidant gas or a fuel gas on at least one surface of the separator facing the electrolyte / electrode structure. A plurality of reaction gas flow passage blocks for flowing a gas along a straight flow passage extending in the long side direction of the separator are independently provided in the short side direction, and the reaction gas flows are adjacent to each other in the short side direction. The reaction gas flow directions of the passage blocks are set to be opposite to each other.

Therefore, the reaction gas flow path block is set such that the dimension in the width direction is within a relatively narrow range, and the flow of the reaction gas is less likely to be non-uniform in the width direction. Therefore, the reaction distribution can be made uniform within the rectangular reaction surface forming the electrolyte / electrode assembly.

Moreover, the reaction gas flow directions of the reaction gas flow path blocks adjacent to each other are set to be opposite to each other,
It becomes possible to effectively prevent the generation of stagnant water in the reaction gas flow path block. In this case, especially during continuous power generation, the current density tends to concentrate on the upstream side of the reaction gas flow channel, but the reaction gas flow direction of the adjacent reaction gas flow channel block is reversed, so the current density in the reaction plane Can be made uniform. This makes it possible to reliably maintain a good power generation state even during high-load power generation.

Further, in the polymer electrolyte fuel cell according to claim 2 of the present invention, a plurality of separators for allowing the oxidant gas to flow along the linear flow path are provided on the surface of one of the separators facing the electrolyte / electrode structure. The oxidant gas flow path block is independently provided, and a plurality of fuel gas flow path blocks for flowing the fuel gas along the straight flow path are provided on the surface of the other separator facing the electrolyte / electrode structure. It is provided independently.

The oxidant gas flow direction of the opposing oxidant gas flow path block and the fuel gas flow direction of the fuel gas flow path block are set opposite to each other. Therefore, the upstream side of the fuel gas flow path block having a small amount of water and the downstream side of the oxidant gas flow path block having a large amount of water are opposed to each other.

Therefore, since the electrolyte / electrode assembly is not partially dried and accumulated water is not generated, the water content of the solid polymer electrolyte membrane constituting the electrolyte / electrode assembly is entirely reduced. It is possible to maintain the uniform. This makes it possible to effectively maintain the solid polymer electrolyte membrane in a desired warmed state with a simple structure and reliably obtain a good power generation function.

Furthermore, in the polymer electrolyte fuel cell according to claim 3 of the present invention, the separator is formed in a rectangular shape, and at least one of the separators has an oxidizing agent on the surface facing the electrolyte / electrode structure. A plurality of reaction gas flow path blocks for allowing a reaction gas, which is a gas or a fuel gas, to flow along a straight flow path extending in the long side direction of the separator is independently provided in the short side direction. The reaction gas flow directions of the reaction gas flow path blocks are set in the vertical direction.

As a result, the fuel cell is set so that the long side direction is the vertical direction, and therefore, for example, when the fuel cell stack is configured and used for vehicle mounting, it can be effectively incorporated in the front box of the vehicle. . Moreover, since the generated water moves downward due to gravity, it is possible to prevent the accumulated water from being generated in the reaction gas flow path block.

Furthermore, in the polymer electrolyte fuel cell according to claim 4 of the present invention, the oxidant gas is caused to flow along the straight flow path on the surface of one of the separators facing the electrolyte / electrode structure. A plurality of oxidant gas flow path blocks are provided independently, and a plurality of fuel gas flow path blocks for flowing a fuel gas along a straight flow path on the surface of the other separator facing the electrolyte / electrode structure. Are provided independently.

The oxidant gas flow direction of the opposing oxidant gas flow path block and the fuel gas flow direction of the fuel gas flow path block are both set to go from the lower side to the upper side. Therefore, in particular, the generated water on the downstream side of the oxidant gas flow path block, that is, on the upper side, moves to the lower side by gravity and flows uniformly in the reaction surface. Therefore, while maintaining a uniform water content of the electrolyte-electrode assembly,
The generated water can diffuse back to the fuel gas flow path block side to effectively humidify the anode electrode.

Further, in the polymer electrolyte fuel cell according to claim 5 of the present invention, a cooling medium for cooling the electrolyte / electrode assembly is caused to flow along a straight flow path extending in the long side direction of the separator. Therefore, a plurality of cooling medium flow passage blocks are independently provided in the short side direction, and the cooling medium flow direction of each of the cooling medium flow passage blocks is set to go from the lower side to the upper side. . As a result, air does not stay in the cooling medium flow path block, and the cooling medium can be smoothly and reliably flowed.

Moreover, the cooling medium is cooled from the lower side to the upper side by cooling the reaction surface, that is,
The temperature rises from the upstream side to the downstream side of the oxidant gas flow path block. Therefore, on the downstream side of the oxidant gas flow path block, although the oxidant gas has a high humidity due to the generated water, the relative humidity of the oxidant gas decreases due to the temperature increase on the downstream side. Therefore, the partial pressure of water vapor becomes high on the downstream side of the oxidant gas flow path block, the dischargeability of the generated water is improved, and the current density distribution can be made uniform to reduce the concentration overvoltage.

[0025]

1 is an exploded perspective view of a main part of a polymer electrolyte fuel cell 10 according to a first embodiment of the present invention, and FIG. 2 is a partial sectional view of the fuel cell 10. Is.

The fuel cell 10 includes an electrolyte membrane / electrode structure (electrolyte / electrode assembly) 14 and first and second separators 16 and 1 for sandwiching the electrolyte membrane / electrode structure 14.
8 and. The electrolyte membrane / electrode structure 14 and the first
A seal (not shown) is interposed between the second separators 16 and 18 and the periphery of a communication hole described below and the outer periphery of the electrode surface.

[0027] Electrolyte membranes each having a rectangular shape
Electrode structure 14 and first and second separators 16, 18
On one end edge (short side) in the long side direction (arrow B direction) of
A first oxidant gas supply communication hole 20a for supplying an oxidant gas, for example, an oxygen-containing gas, and a fuel gas, for example, a hydrogen-containing gas, which communicate with each other in the direction of arrow A, which is the stacking direction. First fuel gas discharge communication hole 22b, second fuel gas supply communication hole 26 for supplying fuel gas
and a second oxidant gas discharge communication hole 24b for discharging the oxidant gas.

Fuel gas is supplied to the other end edges (shorter sides) in the long side direction of the electrolyte membrane / electrode structure 14 and the first and second separators 16 and 18 so as to communicate with each other in the direction of arrow A. Fuel gas supply communication hole 22a for discharging, oxidant gas discharge communication hole 20b for discharging oxidant gas,
A second oxidant gas supply communication hole 24a for supplying the oxidant gas and a second fuel gas discharge communication hole 26b for discharging the fuel gas are provided.

First and second cooling media for supplying a cooling medium such as pure water or ethylene glycol or oil to the lower end edges of the electrolyte membrane / electrode structure 14 and the first and second separators 16 and 18. Supply communication holes 28a, 30a are provided, and first and second cooling medium discharge communication holes 28b, 30b for discharging the cooling medium are provided at the upper edge portion.
Is provided.

The electrolyte membrane / electrode structure 14 is, for example, a solid polymer electrolyte membrane (electrolyte) 32 formed by impregnating a thin film of perfluorosulfonic acid with water, and an anode side sandwiching the solid polymer electrolyte membrane 32. An electrode 34 and a cathode side electrode 36 are provided. The anode-side electrode 34 and the cathode-side electrode 36 are electrode catalysts in which a gas diffusion layer made of carbon paper or the like and porous carbon particles carrying platinum alloy on the surface are uniformly applied to the surface of the gas diffusion layer. And layers, respectively.

As shown in FIGS. 1 and 3, on the surface 16a of the first separator (one separator) 16 on the electrolyte membrane / electrode structure 14 side, the short side direction (arrow C direction) is divided into a plurality of parts. For example, the first and second oxidant gas flow path blocks (reaction gas flow path blocks) 38 are divided into two parts, respectively.
a and 38b are provided independently. The first and second oxidant gas flow path blocks 38a, 38b are provided with a predetermined number of straight flow paths 40a, 40b extending parallel to the long side direction (arrow B direction), respectively.

Both ends of the straight flow path 40a have communication passages 42a,
The first oxidant gas supply communication hole 20a and the first oxidant gas discharge communication hole 20b communicate with each other via 42b. Communication passage 4
2a and 42b are expanded from the first oxidant gas supply communication hole 20a and the first oxidant gas discharge communication hole 20b and are connected to both ends of the first oxidant gas flow path block 38a, and are embossed respectively. A diffuser function is provided by providing 44a and 44b.

Both ends of the second oxidant gas flow path block 38b, and the second oxidant gas supply communication hole 24a and the second oxidant gas discharge communication hole 24b similarly have communication passages 42a and 42b having a diffuser function. Communicate with each other. First and second oxidant gas flow path blocks 38a, 38b
Are set such that the flow directions of the respective oxidant gases are opposite to each other.

As shown in FIG. 4, on the surface 18a of the second separator 18 facing the anode-side electrode 34, the lateral direction is divided into a plurality of parts, for example, two parts, which are the first and second fuel gas flows, respectively. Channel block (reaction gas channel block) 4
6a and 46b are provided. The first and second fuel gas flow path blocks 46a and 46b are provided with a predetermined number of linear flow paths 48a and 48b extending in parallel with the arrow B direction, and the respective fuel gas flow directions are set to be opposite to each other. Has been done.

Both ends of the first fuel gas flow path block 46a are in communication with the first fuel gas supply communication hole 22a and the first fuel gas discharge communication hole 22b through the communication passages 50a and 50b. The communication passages 50a and 50b are provided with a first fuel gas supply communication hole 22a and a first fuel gas discharge communication hole 2, respectively.
The diffuser function is provided by expanding from 2b toward both ends of the first fuel gas flow path block 46a and providing the embossed portions 52a and 52b.

Both end portions of the second fuel gas flow path block 46b and the second fuel gas supply communication hole 26a and the second fuel gas discharge communication hole 26b are similarly connected via communication passages 50a and 50b having a diffuser function. It is in communication.

As shown in FIG. 5, a cooling medium passage 54 is provided on the surface 18b of the second separator 18 opposite to the surface 18a. The cooling medium flow passage 54 is provided with a predetermined number of linear flow passages 56 extending parallel to the vertical direction (direction of arrow C). Both ends of the linear flow path 56 have first and second ends.
Cooling medium supply communication holes 28a, 30a, and first and second
It communicates with the cooling medium discharge communication holes 28b and 30b.

The operation of the fuel cell 10 thus constructed will be described below.

As shown in FIG. 1, in the fuel cell 10,
A fuel gas such as a hydrogen-containing gas, an oxidant gas such as air that is an oxygen-containing gas, and a cooling medium such as pure water, ethylene glycol, or oil are supplied. As shown in FIGS. 1 and 3, the oxidant gas supplied to the first oxidant gas supply communication hole 20a communicating in the direction of arrow A is the first oxidant gas flow path block 38a of the first separator 16 as shown in FIGS. To passage 42
It is introduced via a. In the first oxidant gas flow path block 38a, the oxidant gas moves in the direction of arrow B1 via the linear flow path 40a and moves along the cathode side electrode 36 forming the electrolyte membrane / electrode structure 14.

Similarly, the oxidizing gas supplied to the second oxidizing gas supply communication hole 24a communicating in the direction of arrow A is
The second oxidant gas flow path block 38 of the first separator 16
It is introduced into b through the communication passage 42a. In the second oxidant gas flow path block 38b, the oxidant gas is supplied in the straight flow path 4
It moves in the direction of the arrow B2 via 0b, and moves along the cathode side electrode 36 forming the electrolyte membrane / electrode structure 14.

On the other hand, as shown in FIGS. 1 and 4, the fuel gas is communicated in the direction of arrow A from the first and second fuel gas supply communication holes 22a and 26a to the second separator 18.
First and second fuel gas flow path blocks 46a, 46b
Are introduced via the communication passages 50a.

In the first fuel gas flow path block 46a, the fuel gas moves in the direction of arrow B2 through the straight flow path 48a, and in the second fuel gas flow path block 46b, the fuel gas passes through the straight flow path 48b. Move in the direction of arrow B1. Therefore, the fuel gas is used as the electrolyte membrane / electrode structure 14
Moves along the anode-side electrode 34 constituting the.

Therefore, in the electrolyte membrane / electrode structure 14,
The oxidant gas supplied to the cathode side electrode 36 and the fuel gas supplied to the anode side electrode 34 are consumed by an electrochemical reaction in the electrode catalyst layer to generate electricity (FIG. 2).
reference).

Next, the oxidant gas supplied to the cathode side electrode 36 and consumed is discharged to the first and second oxidant gas discharge communication holes 20b and 24b through the communication passage 42b (see FIG. 3). . Similarly, the fuel gas supplied to the anode electrode 34 and consumed is discharged to the first and second fuel gas discharge communication holes 22b and 26b through the communication passage 50b (see FIG. 4).

The cooling medium supplied to the first and second cooling medium supply communication holes 28a and 30a is introduced into the cooling medium flow path 54 of the second separator 18. The cooling medium moves vertically upward along the linear flow path 56 to cool the electrolyte membrane / electrode structure 14, and then is discharged to the first and second cooling medium discharge communication holes 28b and 30b (FIG. 1 and FIG. 5).

In this case, in the first embodiment, as shown in FIG. 3, on the surface 16a of the first separator 16, the first and second oxidant gas flow path blocks 38a, which are vertically divided into two, are provided. 38b is provided independently. And
Both ends of the first oxidant gas flow path block 38a communicate with the first oxidant gas supply communication hole 20a and the first oxidant gas discharge communication hole 20b, and both ends of the second oxidant gas flow path block 38b. Second oxidant gas supply communication hole 24a
And the second oxidant gas discharge communication hole 24b communicates with each other.

Similarly, as shown in FIG. 4, the surface 18a of the second separator 18 is provided with the first and second fuel gas flow path blocks 46a and 46b which are vertically divided into two. There is. Both ends of the first fuel gas flow passage block 46a communicate with the first fuel gas supply communication hole 22a and the first fuel gas discharge communication hole 22b, and both ends of the second fuel gas flow passage block 46b communicate with the second fuel gas. It communicates with the supply communication hole 26a and the second fuel gas discharge communication hole 26b.

At this time, the first and second oxidant gas flow path blocks 38a and 38b and the first and second fuel gas flow path blocks 46a and 46b are respectively provided with a predetermined number of linear flow paths 40a, 40b and 48a. , 48b to form a linear flow path whose dimension in the width direction (arrow C direction) is set within a relatively narrow range.

Therefore, on the electrode surfaces of the cathode-side electrode 36 and the anode-side electrode 34 of the electrolyte membrane / electrode structure 14, it is possible to suppress fluctuations in the supply amounts of the oxidizing gas and the fuel gas, which are reaction gases. However, the reaction distribution can be made uniform, and the generation of accumulated water on the downstream side of the reaction gas channel can be effectively prevented.

Further, in the fuel cell 10, particularly during continuous power generation (during high load power generation), the current density is likely to concentrate on the upstream side of the reaction gas passage. For example, in FIG. 3, the first and second oxidations are performed. A high current density is likely to occur near the agent gas supply communication holes 20a and 24a.

Here, in the first embodiment, as shown in FIG. 3, the oxidant gas flow direction of the first oxidant gas flow path block 38a is set to the arrow B1 direction, and the second oxidant gas is supplied. The flow direction of the oxidizing gas in the gas flow path block 38b is set in the arrow B2 direction opposite to the arrow B1 direction.

Therefore, the first and second oxidant gas supply communication holes 20a, 24a are provided at both ends (short side) of the first separator 16 in the direction of arrow B, and the current in the cathode side electrode 36 is increased. It is possible to make the density uniform. As a result, it is possible to reliably maintain a good power generation state even during high-load power generation.

Furthermore, in the first and second oxidant gas flow passage blocks 38a and 38b, there is no folding back of the flow passages or variation in the number of flow passages. Therefore, abnormal heating may occur due to the difference in cooling efficiency due to the cooling medium, turbulent flow of the oxidant gas may occur, fluctuation of the flow rate of the oxidant gas may occur, and stagnant water may occur. Therefore, it is possible to avoid the influence of these differences in the power generation environment. In addition, the first
In the above embodiment, only the oxidizing gas is used for description, but the same effect can be obtained on the fuel gas side.

Furthermore, in the first embodiment, as shown in FIGS. 3 and 4, the first oxidant gas flow path block 38a, the first fuel gas flow path block 46a, and the second oxidant gas that face each other are provided. In the flow passage block 38b and the second fuel gas flow passage block 46b, the oxidant gas flow direction and the fuel gas flow direction are set to be opposite to each other.

Therefore, the upstream side of the first and second fuel gas flow path blocks 46a and 46b having a small water content and the first and second oxidant gas flow path blocks 38a having a large water content,
Since the downstream side of 38b is opposed, the electrolyte membrane / electrode structure 14 is not partially dried or accumulated water is not generated. Thereby, the solid polymer electrolyte membrane 32
It is possible to keep the water content of
There is an advantage that a good power generation function can be surely maintained through the electrolyte membrane / electrode structure 14.

Further, the first and second oxidant gas supply communication holes 20a and 24a are set vertically above the first and second oxidant gas discharge communication holes 20b and 24b, and the first fuel gas The supply communication holes 22a and 26a are set vertically above the first and second fuel gas discharge communication holes 22b and 26b. Therefore, the oxidant gas and the fuel gas, which are reaction gases, flow from the upper side to the lower side along the direction of gravity, so that the produced water does not particularly stay and has an effect of having a good drainage property.

Further, in the first embodiment, since the long side direction is set in the horizontal direction (direction of arrow B), the dimension in the height direction is effectively shortened. Therefore, by stacking the fuel cells 10 in the direction of arrow A to form a fuel cell stack, it becomes possible to effectively incorporate the fuel cell 10 under the floor or the like of the vehicle, particularly when used for vehicle mounting.

FIG. 6 is a partial front view of the first separator 60 constituting the fuel cell according to the second embodiment of the present invention. The same components as those of the first separator 16 constituting the fuel cell 10 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The first separator 60 includes the first oxidant gas flow path block 38a and the first oxidant gas supply communication hole 2
0a is provided with a communication passage 62. Communication passage 62
Replaces the embossed portion 44a of the communication passage 42a and arranges a predetermined number of fin members 64 at a predetermined position to form a diffuser.

Thus, in the communication passage 62 having the fin member 64, like the communication passage 42a having the embossed portion 44a, the first oxidant gas supply communication hole 20a extends to the first oxidant gas flow path block 38a. The supplied oxidant gas is
The oxidant gas can be reliably supplied through the diffuser function, and the oxidant gas can be satisfactorily supplied along the electrode surface of the cathode side electrode 36.

FIG. 7 is an exploded perspective view of essential parts of a polymer electrolyte fuel cell 70 according to a third embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The fuel cell 70 has a rectangular electrolyte membrane / electrode structure 72, and first and second separators 7 sandwiching the electrolyte membrane / electrode structure 72.
4 and 76, which are arranged with their long sides in the vertical direction (direction of arrow C).

The first oxidant gas is supplied to one end edge (lower end edge) of the electrolyte membrane / electrode structure 72 and the first and second separators 74 and 76 in the long side direction so as to communicate with each other in the direction of arrow A. The communication hole 20a, the first fuel gas supply communication hole 22a, the second oxidant gas supply communication hole 24a, and the second fuel gas supply communication hole 26a are sequentially provided along the arrow B2 direction.

The other end edge (upper edge) of the electrolyte membrane / electrode structure 72 and the first and second separators 74, 76 in the long side direction communicate with each other in the direction of arrow A to discharge the first fuel gas. The communication hole 22b, the first oxidant gas discharge communication hole 20b, the second fuel gas discharge communication hole 26b, and the second oxidant gas discharge communication hole 24b are sequentially provided in the direction of arrow B2.

At both ends of the electrolyte membrane / electrode structure 72 and the first and second separators 74 and 76 in the short side direction, the first and second cooling medium supply communication holes 28a and 30a are formed on the lower side.
And the first and second cooling medium discharge communication holes 28b and 30b are provided on the upper side.

As shown in FIGS. 7 and 8, the surface 74a of the first separator 74 on the cathode side electrode 36 side is divided into, for example, two parts in the short side direction (arrow B direction), respectively. The second oxidant gas flow path blocks (reaction gas flow path blocks) 78a and 78b are independently provided. First
And the second oxidant gas flow path blocks 78a, 78b are
A predetermined number of linear flow paths 80a and 80b extending in parallel in the vertical direction (direction of arrow C), which is the long-side direction, are provided. The lower ends of the straight flow passages 80a and 80b are connected to the communication passage 42a.
Through the first and second oxidant gas supply communication holes 20a,
While communicating with 24a, the first and second oxidant gas discharge communication holes 20b, 24b are provided on the upper end side through a communication passage 42b.
Communicate with.

As shown in FIG. 9, the first and second fuel gas flow path blocks (reaction gas flow path blocks) are provided on the surface 76a of the second separator 76 facing the anode electrode 34.
82a and 82b are provided. The lower end sides of the first and second fuel gas flow path blocks 82a and 82b have communication passages 50a.
Through the first and second fuel gas supply communication holes 22a, 2
While communicating with 6a, the upper end side communicates with the first and second fuel gas discharge communication holes 22b, 26b through a communication passage 50b. First and second fuel gas flow path blocks 82a,
The reference numeral 82b includes a predetermined number of linear flow paths 84a and 84b that extend in parallel in the vertical direction.

As shown in FIGS. 7 and 10, first and second cooling medium flow path blocks 86a and 86b are provided on the surface 76b of the second separator 76, which is opposite to the surface 76a. First and second cooling medium flow path blocks 86a, 8
6b are straight flow paths 8 extending in parallel to the vertical direction.
8a, 88b, the linear flow path 88a,
The lower side and the upper side of 88b are respectively the first and second cooling medium supply communication holes 28a and 30a and the first and second cooling medium supply communicating holes 28a and 30a.
It is bent and formed in the horizontal direction so as to communicate with the cooling medium discharge communication holes 28b and 30b.

In the fuel cell 70 thus constructed,
The oxidant gas is supplied to the first and second oxidant gas supply communication holes 20a and 24a provided on the lower side, and the first and second fuel gas supply communication holes 22a and 26a are also supplied.
Is supplied with fuel gas. The oxidant gas supplied to the first and second oxidant gas supply communication holes 20a and 24a is introduced into the first and second oxidant gas flow path blocks 78a and 78b of the first separator 74.

As shown in FIGS. 7 and 8, in the first and second oxidant gas flow passage blocks 78a and 78b, the oxidant gas moves vertically upward through the respective linear flow passages 80a and 80b. . The oxidant gas moves upward along the cathode side electrode 36 forming the electrolyte membrane / electrode structure 72, and is then discharged from the first and second oxidant gas discharge communication holes 20b and 24b.

On the other hand, the fuel gas is introduced to the lower side of the first and second fuel gas flow path blocks 82a and 82b of the second separator 76, as shown in FIG. In the first and second fuel gas flow path blocks 82a and 82b, the fuel gas moves vertically upward through the linear flow paths 84a and 84b, respectively. Therefore, the fuel gas moves upward along the anode-side electrode 34 forming the electrolyte membrane / electrode structure 72, and then the first and second fuel gas discharge communication holes 22.
It is discharged from b and 26b (see FIG. 7).

Therefore, in the electrolyte membrane / electrode structure 72,
Electric power is generated by the oxidant gas supplied to the cathode side electrode 36 and the fuel gas supplied to the anode side electrode 34. At that time, the power generation surface (reaction surface) is cooled by the cooling medium.

That is, as shown in FIGS. 7 and 10, the first and second cooling medium supply communication holes 28a, 30a.
The cooling medium supplied to the second separator 76 is introduced to the lower side of the first and second cooling medium flow path blocks 86a and 86b of the second separator 76. First and second cooling medium flow path block 8
In 6a and 86b, the cooling medium has straight flow paths 88a and 88b.
After moving vertically through the flow path, it flows horizontally and is discharged from the first and second cooling medium discharge communication holes 28b and 30b.

In this case, in the third embodiment, the electrolyte membrane / electrode structure 72 and the first and second separators 74 and 7 are used.
6 and 6 are formed in a rectangular shape, and the long side direction is set in the vertical direction. Therefore, if a predetermined number of fuel cells 70 are stacked in the direction of arrow A to form a fuel cell stack, the fuel cells can be effectively incorporated in the front box of the vehicle when used as a vehicle.

Further, in the fuel cell 70, the straight flow passage 80 forming the first and second oxidant gas flow passage blocks 78a and 78b on the surface 74a of the first separator 74.
a and 80b are provided in the vertical direction, and the oxidizing gas flows in the vertical direction, specifically, from the lower side to the upper side.

Therefore, in the first and second oxidant gas flow path blocks 78a and 78b, generated water is likely to be generated on the upper side which is the downstream side, but this generated water surely moves to the lower side due to gravity, It is possible to uniformly flow in the reaction surface of the electrolyte membrane / electrode structure 72. As a result, the water content of the electrolyte membrane / electrode structure 72 is maintained uniform, and the produced water is generated by the first and second oxidant gas flow path blocks 78a, 7a.
8b to first and second fuel gas flow path blocks 82a,
There is an effect that it is possible to back-diffuse to the 82 b side and effectively humidify the anode 34.

Furthermore, the surface 76 of the second separator 76
First and second cooling medium flow path block 8 provided in b
6a and 86b are similar to the oxidant gas and the fuel gas,
The flow direction of the cooling medium is set from the lower side to the upper side. For this reason, air does not stay in the first and second cooling medium flow path blocks 86a and 86b,
The cooling medium can be made to flow smoothly and reliably.

Moreover, the temperature of the cooling medium rises by cooling the reaction surface of the electrolyte membrane / electrode structure 72,
The temperature rises from the upstream side (lower side) of the first and second cooling medium flow path blocks 86a and 86b toward the downstream side (upper side). As a result, in the first and second oxidant gas flow path blocks 78a and 78b, although the oxidant gas has high humidity due to the generated water on the upper side which is the downstream side,
By raising the temperature of the upper side, the relative humidity of the oxidant gas decreases. Therefore, the water vapor partial pressure is increased above the first and second oxidant gas flow path blocks 78a, 78b, so that the drainage of the generated water is improved, the current density distribution is made uniform, and the concentration overvoltage is reduced. The advantage is that

In the first to third embodiments, the first
And the second separator 16 (60, 74), 18 (7
6), the first and second oxidant gas flow path blocks 38a (78a) and 38b (78b) and the first and second fuel gas flow path blocks 46a (82a) and 46b divided into two parts.
(82b) is provided independently, but is not limited to this. This type of reaction gas flow path block may be independently configured into, for example, three divisions, four divisions, or five divisions or more. In that case, it is preferable to set the number of divisions to an even number, because the reaction in the electrode surface can be easily made uniform.

Further, the anode side electrode 34 and the cathode side electrode 36 are each formed in a single structure, but may be formed in a plurality of parts corresponding to the reaction gas flow path block. Thereby, the electrode material can be saved, which is economical.

[0081]

In the polymer electrolyte fuel cell according to the present invention, the reaction gas flow path block provided on at least one of the separators along the long side direction has a widthwise dimension set within a relatively narrow range. Since it is constituted by the linear flow path, the flow of the reaction gas becomes uniform in the width direction, and the reaction distribution can be made uniform in the rectangular reaction surface.

Moreover, the reaction gas flow directions of the reaction gas flow passage blocks adjacent to each other are set to be opposite to each other,
It is possible to effectively prevent the generation of stagnant water in the reaction gas flow path block and make the current density in the power generation surface uniform. As a result, even during high load power generation,
It is possible to reliably maintain a good power generation state.

Further, according to the present invention, a plurality of reaction gas flow path blocks are independently provided in the short side direction in order to flow the reaction gas along the straight flow path extending in the long side direction in the rectangular separator. In addition, the reaction gas flow direction of the reaction gas flow path block is set to the vertical direction. Therefore, the long side direction of the fuel cell is set to the up-down direction, and for example, when the fuel cell stack is configured and used for vehicle mounting, it can be effectively incorporated in the front box of the vehicle.

Moreover, since the flow direction of the reaction gas is set up and down, the generated water is smoothly discharged to the lower side by gravity, and it is possible to reliably prevent the accumulated water from being generated in the reaction gas flow path block. Will be possible.

[Brief description of drawings]

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

FIG. 2 is a partial cross-sectional view of the fuel cell.

FIG. 3 is a front view showing a first separator constituting the fuel cell.

FIG. 4 is a front explanatory view of one surface of a second separator constituting the fuel cell.

FIG. 5 is a front explanatory view of the other surface of the second separator.

FIG. 6 is a partial front view showing a first separator constituting a fuel cell according to a second embodiment of the present invention.

FIG. 7 is an exploded perspective view of essential parts of a fuel cell according to a third embodiment of the present invention.

FIG. 8 is a front explanatory view of a first separator constituting the fuel cell.

FIG. 9 is a front explanatory view of one surface of a second separator that constitutes the fuel cell.

FIG. 10 is a front view showing the other surface of the second separator.

FIG. 11 is a front explanatory view of a current collector plate according to a conventional technique.

[Explanation of symbols]

10, 70 ... Fuel cell 14, 72 ... Electrolyte membrane / electrode structure 16, 18, 60, 74, 76 ... Separator 20a, 24a ... Oxidizing gas supply communication hole 20b, 24b ... Oxidizing gas discharge communication hole 22a, 26a ... Fuel gas supply communication holes 22b, 26b
... Fuel gas discharge communication holes 28a, 30a ... Cooling medium supply communication holes 28b, 30b
... Cooling medium discharge communication hole 32 ... Solid polymer electrolyte membrane 34 ... Anode side electrode 36 ... Cathode side electrodes 38a, 38b, 78a, 78b ... Oxidant gas flow path blocks 40a, 40b, 48a, 48b, 56, 80a, 80
b, 84a, 84b, 88a, 88b ... Linear flow passages 42a, 42b, 50a, 50b, 62 ... Communication passages 44a, 44b, 52a, 52b ... Embossed portions 46a, 46b, 82a, 82b ... Fuel gas flow passage block 54 ... Cooling medium flow channel 64 ... Fin members 86a, 86b ... Cooling medium flow channel block

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiya Wakaho             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory (72) Inventor Shigetoshi Sugita             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory F-term (reference) 5H026 AA06 CC03 CC08                 5H027 AA06

Claims (5)

[Claims] 1. A polymer electrolyte fuel cell comprising an electrolyte / electrode structure having electrodes on both sides of the electrolyte and a pair of separators sandwiching the electrolyte / electrode structure, wherein the separator is The reaction gas, which is an oxidant gas or a fuel gas, is formed on a surface of at least one of the separators facing the electrolyte / electrode structure in a straight line extending in the long side direction of the separator. A plurality of reaction gas flow path blocks for flowing along the path are independently provided in the short side direction, and the reaction gas flow directions of the reaction gas flow path blocks adjacent to each other in the short side direction are set to opposite directions. And a polymer electrolyte fuel cell. 2. The polymer electrolyte fuel cell according to claim 1, wherein one of the separators is provided with an oxidant gas flow channel block as the reaction gas flow channel block, and the other separator is provided with the oxidant gas flow channel block. A fuel gas flow path block is provided as a reaction gas flow path block, and the oxidant gas flow direction of the opposing oxidant gas flow path block and the fuel gas flow direction of the fuel gas flow path block are set opposite to each other. And a polymer electrolyte fuel cell. 3. A polymer electrolyte fuel cell comprising an electrolyte / electrode structure having electrodes on both sides of the electrolyte, and a pair of separators sandwiching the electrolyte / electrode structure, wherein the separator is The reaction gas, which is an oxidant gas or a fuel gas, is formed on a surface of at least one of the separators facing the electrolyte / electrode structure in a straight line extending in the long side direction of the separator. A plurality of reaction gas flow path blocks for flowing along the path are independently provided in the short side direction, and the reaction gas flow directions of the reaction gas flow path blocks are set to the vertical direction. Polymer electrolyte fuel cell. 4. The polymer electrolyte fuel cell according to claim 3, wherein one of the separators is provided with an oxidant gas flow path block as the reaction gas flow path block, and the other separator is provided with the oxidant gas flow path block. A fuel gas flow path block is provided as the reaction gas flow path block, and the oxidant gas flow direction of the opposing oxidant gas flow path block and the fuel gas flow direction of the fuel gas flow path block are both from the lower side to the upper side. A polymer electrolyte fuel cell characterized by being set so as to face toward the side. 5. The polymer electrolyte fuel cell according to claim 3 or 4, wherein a cooling medium for cooling the electrolyte / electrode assembly is provided along a straight flow path extending in the long side direction of the separator. A plurality of cooling medium flow passage blocks for flowing are provided independently in the short side direction, and the cooling medium flow direction of each of the cooling medium flow passage blocks is set to go from the lower side to the upper side. A polymer electrolyte fuel cell characterized by: