JPH08138700A - Fuel cell - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a fuel cell that alleviates a voltage drop due to a resistance overvoltage of a constituent member and a current collector for extracting electric power. A battery cell 6 having a positive catalyst electrode 8 on one surface of an ion exchange membrane 7 and a negative catalyst electrode 9 on the other surface thereof is provided, and a reaction gas is reacted by the battery cell 6 to generate electricity. In the fuel cell 1 to be operated, the battery cells 6 are held by the separator 4, and the separator 4 is provided with a current collecting plate 80 in electrical communication with the catalyst electrode and provided with current collecting layers 82, 83 in contact with the catalyst electrode. Electric layer 82,
83 and the collector plate 80 are connected by conductive members 84 and 85.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell in which a reaction gas is reacted to produce water and electricity is generated at that time.

[0002]

2. Description of the Related Art Some electric vehicles are equipped with, for example, a fuel cell and run using electricity generated by the fuel cell as a drive source. This fuel cell is provided with a battery cell having a positive catalyst electrode on one side of the ion exchange membrane and a negative catalyst electrode on the other side of the ion exchange membrane. To generate electricity.

[0003]

As described above, the performance of the fuel cell is shown by the current-voltage characteristic as shown in FIG. 7, and the actual voltage is lower than the theoretical voltage value. The causes of this voltage drop include, for example, activation overvoltage due to the structure of the catalyst electrode of the fuel cell and its surrounding members, resistance overvoltage of the fuel cell constituent members and the current collecting part for extracting electric power, supply of hydrogen and oxygen of the reaction gas, The influence of water generated by the reaction, concentration overvoltage due to reaction gas, etc. are considered.

[0004] In particular, the following are specific phenomena that cause resistance overvoltage in the constituent members of the fuel cell and the current collecting portion for extracting electric power. For example, a battery cell reacts hydrogen and oxygen of a reaction gas to generate water, and electricity is generated at that time. In the case where battery cells are stacked to form a battery cell stack, lead wires, etc. If it is used, it is difficult to connect it to the catalyst electrode, it is not easy to secure a space for wiring, and the power extraction position is limited. Further, there is a problem that the contact resistance with the catalyst electrode is large and the electric power cannot be efficiently extracted.

The present invention has been made in view of the above points, and the inventions according to claims 1 to 3 provide a fuel cell for reducing a voltage drop due to a resistance overvoltage of a constituent member and a current collecting portion for extracting electric power. The purpose is to do. In particular,
It is an object of the present invention to provide a fuel cell capable of efficiently collecting electric power from a battery cell and taking out electric power, and further increasing the degree of freedom of taking out electric power. It is another object of the present invention to provide a fuel cell capable of efficiently extracting electric power by reducing the contact resistance with the catalyst electrode. It is another object of the present invention to provide a fuel cell in which the resistance of the current collector is reduced by using a member having a lower specific resistance in combination, and the degree of freedom in extracting the power is increased.

[0006]

In order to solve the above problems, the invention according to claim 1 has a positive catalyst electrode on one surface of an ion exchange membrane and a negative catalyst electrode on the other surface thereof. In a fuel cell including a cell, in which a reaction gas is reacted by the battery cell to generate electricity, the battery cell is held by a separator, and the separator is provided with a collector plate in electrical communication with the catalyst electrode, and the catalyst The present invention is characterized in that a current collecting layer is provided in contact with the electrodes, and the current collecting layer and the current collecting plate are connected by a conductive member.

According to a second aspect of the present invention, a conductive soft material is laminated on the surface of the current collecting layer, and the soft material is brought into contact with the catalyst electrode.

The invention according to claim 3 is characterized in that a composite layer of a carbon material and a conductive member is laminated on the surface of the catalyst electrode.

[0009]

According to the first aspect of the present invention, the separator is provided with a collector plate in electrical communication with the catalyst electrode, and a collector layer is provided in contact with the catalyst electrode. The collector layer and the collector plate are electrically conductive. Are connected with. As described above, by using the current collecting plate and the current collecting layer, the connection with the catalyst electrode is easier and the wiring space can be secured more easily than the case where the lead wire or the like is used. The shape and pattern of the part can be freely manufactured. Therefore, the power can be efficiently collected from the battery cells to take out the electric power, and the electric power can be taken out from the end portion of the current collecting plate, so that the degree of freedom in assembling the fuel cell is increased.

According to the second aspect of the present invention, since the current collecting portion for taking out the electric power from the catalyst electrode has the conductive soft material, even if the surface pressure is low, the contact with the catalyst electrode is sure and the contact with the catalyst electrode is ensured. It is possible to reduce contact resistance and extract electric power efficiently.

According to the third aspect of the present invention, since the composite layer of the carbon material and the conductive member is laminated on the surface of the catalyst electrode of the battery cell, the specific resistance of the catalyst electrode is reduced and efficient power consumption is achieved. Can be taken out. Further, electric power can be efficiently taken out from any position of the catalyst electrode, and the degree of freedom in taking out electric power is increased.

[0012]

Embodiments of the fuel cell of the present invention will be described below in detail with reference to the drawings.

1 to 3 show an embodiment of a fuel cell according to claim 1, FIG. 1 is a longitudinal sectional view of the fuel cell, and FIG. 2 is FIG.
2 is a cross-sectional view taken along line II-II, and FIG. 3 is a cross-sectional view of an electric power extracting portion of the fuel cell. The fuel cell 1 includes a battery cell stack 3 assembled by an assembly shaft 2. The battery cell stack 3 is formed by alternately stacking a plurality of separators 4 and battery cells 6 and assembling them. The separator 4 is composed of a gasket 4a, a current collecting plate 80, and a gasket 4b. A battery cell 6 is provided between the separators 4 and 4. The battery cell 6 is arranged such that the surface direction of the battery cell 6 is oriented in the up-down direction and the arrangement direction L2 of the battery cell is inclined by an angle α with respect to the installation direction L1 of the battery cell stack 3.

The battery cell 6 is composed of an ion exchange membrane 7, a positive catalyst electrode 8 and a negative catalyst electrode 9. The outer peripheral portion 7a of the ion exchange membrane 7 is the gasket 4 of the separator 4.
It is sandwiched and held between b and the gasket 4a of the opposing separator 4, and the battery cells 6 react hydrogen and oxygen of the reaction gas to generate electricity, and water is generated at that time.

Outside the positive catalyst electrode 8 of the battery cell 6,
A reaction gas passage 12 is provided in which the groove 4c side of the gasket 4b is in contact with the positive catalyst electrode 8 and communicates with the groove 4c of the gasket 4b. Negative catalyst electrode 9 of battery cell 6
A reaction gas passage 13 that contacts the negative catalyst electrode 9 on the groove 4d side of the gasket 4a and communicates with the groove 4d of the gasket 4a is provided outside the reaction gas passage 13. The reaction gas passage 13 is orthogonal to the reaction gas passage 12. It is arranged in the direction to.

Separator 4, 4 surrounding the battery cell 6
The O-rings 14a and 14b are provided between the gaskets 4b and 4a of FIG.
The battery cell 6 is sealed by 4a and 14b. At the upper left corner of the battery cell stack 3, a hydrogen inlet 15 is provided.
And a hydrogen outlet 16 is provided in the lower right corner, and an O-ring 1 is provided between the gasket 4b and the gasket 5a so as to surround the inlet 15 and the outlet 16.
7 and 18 are provided to seal the inlet portion 15 and the outlet portion 16. An inlet passage 15a of the reaction gas passage is formed in the inlet portion 15 in the stacking direction of the battery cells 6, and four tunnel passages 15b are formed from the inlet passage 15a to the O-ring 14.
distribution passage 15c of the battery cell 6 passing below a and 14b
And from the distribution passage 15c to the reaction gas passage 13. An outlet passage 16a of a reaction gas passage is formed in the outlet portion 16 in the stacking direction of the battery cells 6, and the four tunnel passages 16b communicating with the outlet passage 16a pass under the O-rings 14a and 14b. It communicates with the collecting passage 16c of the cell 6, and the collecting passage 16c communicates with the reaction gas passage 13.

An oxygen inlet portion 19 is provided at the upper right corner of the battery cell stack 3, and an oxygen outlet portion 20 is provided at the lower left corner thereof. O-rings 21 and 22 are provided between the gasket 4b and the gasket 4a so as to surround them, and seal the inlet portion 19 and the outlet portion 20. At the inlet portion 19, the battery cell 6
An inlet passage 19a of the reaction gas passage is formed in a stacking direction of the four tunnel passages 19b from the inlet passage 19a.
Communicates with the distribution passage 19c of the battery cell 6 passing below the O-rings 14a and 14b, and from the distribution passage 19c to the reaction gas passage 12. At the outlet portion 20, the battery cell 6
The outlet passage 20a of the reaction gas passage is formed in the stacking direction of the four, and the four tunnel passages 20b communicating with the outlet passage 20a communicate with the collecting passage 20c of the battery cell 6 passing under the O-ring 14. The passage 20c communicates with the reaction gas passage 12.

A water passage 23 is formed in the separator 4b. One side 23a of the water passage 23 is connected to the discharge part 24 provided on the upper side in the vicinity of the hydrogen inlet part 15 via the tunnel passage 24a, and the other side 23b is near the hydrogen outlet part 16 via the tunnel passage 25a. It communicates with the supply unit 25 provided on the lower side. O-rings 26a and 27a are provided between the gasket 4b and the gasket 4a so as to surround the discharge portion 24 and the supply portion 25, and seal the discharge portion 24 and the supply portion 25.

A water passage 28 is formed in the separator 4a. One of the water passages 28a communicates with a discharge portion 29 provided on the right side near the oxygen inlet portion 19 through a tunnel passage 29a, and the other 28b near the oxygen outlet portion 20 through a tunnel passage 30a. It communicates with the supply unit 30 provided on the left side. O-rings 26b and 27b are provided between the gasket 4b and the gasket 4a so as to surround the discharge unit 29 and the supply unit 30, and seal the discharge unit 29 and the supply unit 30.

When heated and humidified hydrogen is supplied from the hydrogen inlet 15 of the battery cell stack 3, the hydrogen containing water is introduced from the inlet passage 15a to the distribution passage 15c through the tunnel passage 15b of the separator 4a. Distribution passage 15
The reaction gas passage 13 flows from c. On the other hand, when heated and humidified oxygen is supplied from the oxygen inlet portion 19, the oxygen containing water communicates with the distribution passage 19c from the inlet passage 19a through the tunnel passage 19b of the separator 4b and the reaction gas from the distribution passage 19c. Flow through passage 12.

At this time, power is generated by the battery cell 6 to generate water by an electrochemical reaction of hydrogen and oxygen of the reaction gas, and to extract the change in free energy at that time as electric energy. Further, mainly hydrogen and water are collected in the collecting passage 16c of the battery cell 6, are guided to the outlet passage 16a through the tunnel passage 16b, and are discharged from the outlet portion 16. Mainly oxygen and water are the collecting passages 20c for the battery cells 6.
Collected at the exit passage 20 through the tunnel passage 20b.
It is guided to a and discharged from the outlet portion 20.

On the other hand, the electrochemical reaction of hydrogen and oxygen by the battery cell 6 is such that oxygen and water pass through the positive catalytic electrode 8,
On the other hand, hydrogen and water are supplied to the surface of the ion exchange membrane 7, pass through the negative catalyst electrode 9 and are supplied to the surface of the ion exchange membrane 7, and the interface between the positive catalyst electrode 8 and the ion exchange membrane 7 and the negative It is performed at the interface between the catalyst electrode 9 and the ion exchange membrane 7.

A collector plate 80 is provided between the gaskets 4a and 4b of the separator 4, and a collector layer 82, which contacts the catalyst electrode, is provided outside the gaskets 4a and 4b.
83 is provided, the current collecting layer 82 and the current collecting plate 80 are connected by the conductive member 84, and the current collecting layer 83 and the current collecting plate 80 are connected by the conductive member 85.

The current collecting plate 80 is made of copper foil, and water channels 28 and 2 are formed on the upper and lower surfaces of the current collecting plate 80, respectively.
3 are formed. The current collecting layer 82 is configured, for example, by providing a copper foil 82a on the surface of the gasket 4a and further providing a gold plating 82b on the copper foil 82a. Similarly, for the current collecting layer 83, for example, the copper foil 8
3a is provided, and further gold plating 83b is provided on the copper foil 83a.

The conductive member 84 is, for example, the gasket 4a.
The hole 4a1 formed in 1 is provided with a copper plating 84a, and further a gold plating 84b is provided on the copper plating 84a. The conductive member 84 forms a water passage 28f that connects the catalyst electrode side and the water passage 28. . Similarly, the conductive member 85 has a hole 4b formed in the gasket 4b, for example.
1 is provided with a copper plating 85a, and further a gold plating 85b is provided on the copper plating 85a.
The water passage 23 that connects the catalyst electrode side and the water passage 23 with each other
f is formed.

As described above, the current collecting plate 80 which is in electrical communication with the catalyst electrode is arranged on the separator 4, and the current collecting layers 82 and 83 which are in contact with the catalyst electrode are provided.
3 and the collector plate 80 are connected by conductive members 84 and 85. For example, a lead wire or the like is connected to the end portion of the current collecting plate 80 to take out electric power from the positive catalyst electrode 8 and the negative catalyst electrode 9 of the ionization cell 6.

In the present invention, by using the current collecting layers 82 and 83, the connection with the catalyst electrode is easier and the wiring space can be secured more easily than the one using the lead wire or the like. The shape and pattern of the electric part can be freely manufactured. Therefore, the power can be efficiently collected from the battery cells 6 to take out the electric power, and the electric power can be taken out from the end portion of the current collecting plate 80 by using a method such as a printed circuit board. The degree of freedom increases.

FIG. 4 is a sectional view showing an embodiment of the current collecting layer according to the second aspect. The current collecting layer 83 in contact with the positive catalyst electrode 8 of this embodiment has a conductive soft material 83d as the current collecting material 83c.
Are formed by stacking. The conductive soft material 83d is composed of, for example, a conductive metal foil, a gold plating layer, or the like.
Further, the current collecting layer 82 in contact with the negative catalyst electrode 9 is formed by laminating the conductive soft material 82d on the current collecting material 82c.
The conductive soft material 82d is composed of, for example, a conductive metal foil, a gold plating layer, or the like.

Therefore, even if the surface pressure of tightening is low due to the assembly of the fuel cell 1, the contact between the current collecting layers 83, 82 and the catalyst electrodes 8, 9 is reliable, and the contact resistance with the catalyst electrodes is reduced. It is possible to take out electric power efficiently.

5 and 6 are views showing an embodiment of the catalyst electrode according to the third aspect. In this embodiment, a composite layer 85 of a carbon material and a conductive member is laminated on the surfaces of the positive and negative catalyst electrodes 8 and 9. In the embodiment of FIG. 5, the composite layer 85 is formed by mixing the conductive metal fiber 85b into the carbon material 85a, and in the embodiment of FIG. 6, the composite layer 85 is formed by laminating the gold plating layer 85d on the carbon material 85c. Has been formed.

As described above, since the composite layer 85 of the carbon material and the conductive member is laminated on the surfaces of the positive and negative catalyst electrodes 8 and 9 of the battery cell 6, the positive and negative catalyst electrodes 8 and 9 are formed. It is possible to efficiently extract the electric power by reducing the specific resistance of. Moreover, electric power can be efficiently taken out from any positions of the positive and negative catalyst electrodes 8 and 9, and the degree of freedom of taking out electric power is increased. In addition, since the positive and negative catalyst electrodes 8 and 9 often use a carbon material as a base material, even if a conductive member is combined with the catalyst electrode itself or a gold plating layer is laminated on the surface. good.

[0032]

As described above, according to the first aspect of the present invention, the separator is provided with the current collecting plate that is in electrical communication with the catalyst electrode, and the current collecting layer that is in contact with the catalyst electrode is provided. Since it is connected to the electric plate with a conductive member,
By using the current collecting plate and the current collecting layer, it is easier to connect to the catalyst electrode and to secure a wiring space, and the shape and shape of the current collecting portion are improved as compared with those using a lead wire or the like. You can freely create patterns. Therefore, the power can be efficiently collected from the battery cells to take out the electric power, and the electric power can be taken out from the end portion of the current collecting plate, so that the degree of freedom in assembling the fuel cell is increased.

According to the second aspect of the present invention, since the current collecting portion for taking out the electric power from the catalyst electrode has a conductive soft material, even if the surface pressure is low, the contact with the catalyst electrode is sure and the contact with the catalyst electrode is ensured. It is possible to reduce contact resistance and extract electric power efficiently.

According to the third aspect of the present invention, since the composite layer of the carbon material and the conductive member is laminated on the surface of the catalyst electrode of the battery cell, the specific resistance of the catalyst electrode is reduced to achieve efficient power consumption. Can be taken out. Further, electric power can be efficiently taken out from any position of the catalyst electrode, and the degree of freedom in taking out electric power is increased.

[Brief description of drawings]

FIG. 1 is a front view of a fuel cell according to claim 1.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a cross-sectional view of a power extraction unit of a fuel cell.

FIG. 4 is a cross-sectional view showing a schematic configuration of an embodiment of the fuel cell according to claim 2.

FIG. 5 is a diagram showing a schematic configuration of an embodiment of the fuel cell according to claim 3;

FIG. 6 is a diagram showing a schematic configuration of another embodiment of the fuel cell according to claim 3;

FIG. 7 is a diagram showing current-voltage characteristics of a fuel cell.

[Explanation of symbols]

 1 Fuel Cell 4 Separator 6 Battery Cell 7 Ion Exchange Membrane 8, 9 Catalyst Electrode 80, 90 Current Collection Plate 82, 83 Current Collection Layer 84, 85 Conductive Member

Claims (3)

[Claims] 1. A fuel cell comprising a battery cell having a positive catalyst electrode on one surface of an ion exchange membrane and a negative catalyst electrode on the other surface thereof, the reaction gas being reacted by the battery cell to generate electricity. In the above, the battery cell is held by a separator, and a current collector plate that is in electrical communication with the catalyst electrode is disposed on the separator, and a current collector layer that is in contact with the catalyst electrode is provided, and the current collector layer and the current collector plate are provided. A fuel cell, wherein the fuel cells are connected by a conductive member. 2. The fuel cell according to claim 1, wherein a conductive soft material is laminated on the surface of the current collecting layer, and the soft material is brought into contact with the catalyst electrode. 3. The fuel cell according to claim 1, wherein a composite layer of a carbon material and a conductive member is laminated on the surface of the catalyst electrode.