JPH08138695A - Fuel cell - Google Patents

Abstract

PURPOSE: To provide a fuel cell wherein concentration over voltage to be generated caused by the effect of water to be formed by supply or reaction of hydrogen or oxygen of the reaction gas is restrained, and the voltage drop caused by the concentration over voltage is decreased. CONSTITUTION: A battery cell 6 provided with a positive catalyst electrode 8 on one surface of an ion exchange membrane 7 and a negative electrode 9 on the other surface is provided, and reaction gas is made to react by the battery cell 6, to generate electricity. In this fuel cell 1, the battery cell 6 is held by separators 4a, 4b, 4c connected through seal members 14, and tunnel passages 15b, 16b, 19b, 20b for communicating the reaction gas passage formed in the laminating direction with the battery cell 6 are formed on the separators 4a, 4b, 4c, so as to extend over gaskets 14 as the seal members into tunnel shapes.

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.

In particular, the following phenomenon is a specific phenomenon in which a concentration overvoltage occurs due to the effects of the supply of hydrogen and oxygen of the reaction gas and the water produced by the reaction. For example, it is important to secure the sealing property of the reaction gas because hydrogen and oxygen are caused to react with each other by the battery cell to generate water and electricity is generated at that time. For example, the battery cell is joined via a seal member. If a reaction gas passage is provided in the sealing surface in the case where the structure is to be held by the separated separator, the sealing surface is not flat and gas sealing is difficult.

In addition, it is necessary to promptly remove the excess water in the mixed gas introduced into the reaction gas or the water generated by the power generation reaction to the outside of the battery cell stack.
Conventionally, as a method for removing such excess water to the outside of the battery cell stack, for example, by tilting the battery cell stack while keeping the battery cells vertical, the water accumulated on the battery cells is removed by gravity and gas. Some of them are removed by the synergistic effect of the flow, but since the battery cell stack is installed at an angle, it is difficult to secure the installation space for that. Further, a tilting stand and a fixture for installing the battery cell stack in a tilted state are required.

Further, it is necessary to promptly remove the excess water in the mixed gas introduced into the reaction gas or the water generated by the power generation reaction to the outside of the battery cell stack. It is difficult to secure the circular discharge part, and the device becomes large accordingly.

The present invention has been made in view of the above points, and the inventions according to claims 1 to 3 provide hydrogen and oxygen as a reaction gas, influence of water generated by the reaction, and concentration of the reaction gas. It is an object of the present invention to provide a fuel cell that suppresses overvoltage and reduces the voltage drop due to this concentration overvoltage. In particular, the invention according to claim 1 aims to provide a fuel cell capable of improving the sealing property of a reaction gas. Further, the invention according to claim 2 can be placed in a slanting state simply by installing it horizontally, and the water of the battery cells can be discharged without using a special device, which is excellent in stability and drainage is easy. In addition, it is an object of the present invention to provide a fuel cell in which the water discharge part can be easily secured and the size can be reduced. In addition, the invention according to claim 3 is easy to drain generated water or excess water, has improved reliability, is inexpensive, lightweight and compact without requiring a special device, and is used over the entire surface without the battery cell being submerged in water. It is an object of the present invention to provide a fuel cell capable of generating electricity with high efficiency.

[0008]

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 and reacting a reaction gas with the battery cell to generate electricity, the battery cell is held by a separator joined through a seal member, and the reaction gas formed in the separator in a stacking direction. A tunnel passage that connects the passage and the battery cell is formed by straddling the seal member in a tunnel shape.

According to a second aspect of the present invention, there is provided a battery cell stack in which battery cells having a positive catalyst electrode on one surface of the ion exchange membrane and a negative catalyst electrode on the other surface thereof are stacked, and each of the battery cells is provided. In the fuel cell in which the reaction gas is supplied to the reaction gas passage, and electricity is generated by the reaction of the reaction gas, the surface direction of the battery cell is oriented vertically,
Moreover, the arrangement direction of the battery cells is inclined with respect to the installation direction of the battery cell stack, and the reaction gas passage is inclined.

According to a third aspect of the present invention, there is provided a battery cell stack in which battery cells having a positive catalyst electrode on one surface of the ion exchange membrane and a negative catalyst electrode on the other surface are stacked, and each of the battery cells is provided. In the fuel cell in which the reaction gas is supplied to the reaction gas passage, and electricity is generated by the reaction of the reaction gas, the surface direction of the battery cell is oriented vertically,
An outlet of the reaction gas is provided below the battery cell of the battery cell stack.

[0011]

According to the first aspect of the invention, the battery cell is held by the separator joined through the seal member, and the reaction gas passage formed in the stacking direction in the separator communicates with the battery cell through the tunnel passage. ing. Since this tunnel passage is formed so as to straddle the seal member in a tunnel shape, when a structure in which the battery cell is held by the separator joined via the seal member is provided, the reaction gas passage is provided on the seal surface. And the sealing surface can be made flat and the sealing performance is improved.

According to the second aspect of the present invention, the surface direction of the battery cells is oriented vertically, and the arrangement direction of the battery cells is inclined with respect to the installation direction of the battery cell stack, and the reaction gas passage is inclined. There is. Therefore, by simply installing the fuel cell horizontally, the reaction gas passages will be in an oblique state, and the water in the battery cells can be discharged without using a special device. Excellent stability and easy drainage. In addition, by arranging the battery cell stack incliningly with respect to the installation direction of the battery cell stack, a large space for providing a water discharge part can be provided in the battery cell stack, and it is easy to secure the water discharge part and is small in size. Is possible.

According to the third aspect of the present invention, the surface direction of the battery cells is oriented in the vertical direction and the reaction gas outlet is provided below the battery cells of the battery cell stack. The drainage of water is simple and the reliability is improved. In addition, it does not require a special device, is inexpensive, lightweight, and compact, and can be used over the entire surface without the battery cell submerged in water, enabling highly efficient power generation.

[0014]

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

1 to 4 show an embodiment of a fuel cell according to claims 1 and 2, FIG. 1 is a vertical sectional view of the fuel cell, and FIG. 2 is a sectional view taken along line II-II of FIG. 3A is a cross-sectional view taken along line XX of FIG. 1, and FIG. 3B is a cross-sectional view of FIG.
Sectional drawing which follows the Y line, FIG. 4 is a perspective view of a fuel cell.

The fuel cell 1 has a battery cell stack 3 assembled by an assembly shaft 2. The battery cell stack 3 is formed by stacking a plurality of separators 4a, 4b and 4c and assembling them, and a gas blocking plate 4d is provided between the separators 4a and 4c.
A tunnel passage 15b is formed between the separator 4c and the gas blocking plate 4d. A battery cell 6 is provided between the separators 4a and 4b. The battery cell 6 is
It is composed of an ion exchange membrane 7, a positive catalyst electrode 8 and a negative catalyst electrode 9, and the surface direction of the battery cell 6 is oriented in the vertical direction, and the battery cell stacking direction L2 with respect to the battery cell stack 3 installation direction L1. Are provided so as to be inclined by an angle α.

The outer peripheral portion 7a of the ion exchange membrane 7 is sandwiched and held between the separators 4a and 4b, and has a positive catalyst electrode 8 on one surface of the ion exchange membrane 7 and a negative catalyst electrode on the other surface. The battery cell 6 reacts the reaction gas hydrogen and oxygen to generate water, and at that time, generates electricity.

Outside the positive catalytic electrode 8 of the battery cell 6,
A porous guide body 10 formed of a porous member is disposed in contact with the porous guide body 10. A porous guide body 11 formed of a porous member is also disposed in contact with the outside of the negative catalyst electrode 9. The porous guide bodies 10 and 11 are formed of a porous porous member, and grooves 10a and 11a are formed on one surface side at equal intervals. Porous guide body 1
In 0, the side where the groove 10a is formed is brought into contact with the positive catalyst electrode 8, and the porous guide body 11 is arranged with the groove 11a oriented in a direction orthogonal to the groove 10a of the porous guide body 10. Groove 10a of porous guide body 10 and positive catalyst electrode 8
A reaction gas passage 12 is provided between the groove 11 a of the porous guide body 11 and the negative catalyst electrode 9, and a reaction gas passage 13 is provided between the groove 11 a and the negative catalyst electrode 9.

In the battery cell stack 3, the battery cells 6 are arranged at an angle α, and a gasket 1 as a sealing member is provided between the separators 4b and 4c surrounding the battery cell 6.
4 is provided, and the battery cell 6 is sealed by the gasket 14. An inlet portion 15 for hydrogen is provided on the upper left side of the battery cell stack 3, and an outlet portion 16 for hydrogen is provided on the lower right side.
Is provided between the separators 4a and 4b so as to surround the inlet 15 and the outlet 16.
8 is provided to seal the inlet portion 15 and the outlet portion 16. An inlet passage 15a is formed in the inlet portion 15 in the stacking direction of the battery cells 6, and four tunnel passages 15b communicate with the distribution passages 15c of the battery cells 6 from below the gasket 14 from the inlet passage 15a. The distribution passage 15c communicates with the reaction gas passage 13. An outlet passage 16a is formed in the outlet portion 16 in the stacking direction of the battery cells 6, and four tunnel passages 16b communicated with the outlet passage 16a.
Communicates with the collecting passage 16c of the battery cell 6 passing under the gasket 14, and the collecting passage 16c communicates with the reaction gas passage 13.

An oxygen inlet portion 19 is provided on the upper right side of the battery cell stack 3, and an oxygen outlet portion 20 is provided on the lower left side thereof.
Is provided between the separators 4a and 4b so as to surround the inlet portion 19 and the outlet portion 20.
Is provided to seal the inlet portion 19 and the outlet portion 20. An inlet passage 19a is formed in the inlet portion 19 in the stacking direction of the battery cells 6, and four tunnel passages 19b communicate with the distribution passage 19c of the battery cell 6 from below the gasket 14 through the inlet passage 19a. The distribution passage 19c communicates with the reaction gas passage 12. An outlet passage 20a is formed in the outlet portion 20 in the stacking direction of the battery cells 6, and the four tunnel passages 20b communicating with the outlet passages 20a pass under the gasket 14 and the collecting passages 2 of the battery cells 6 are formed.
0c, and the collecting passage 20c communicates with the reaction gas passage 12.

A water passage 23 is formed at the contact portion of the gas blocking plate 4d, which is the lower surface in FIG. 2, with the porous guide body 10. One side 23a of the water passage 23 is communicated with a discharge portion 24 provided on the upper side in the vicinity of the hydrogen inlet portion 15 via a tunnel passage 24a passing below the gasket 14, and the other 23b is a tunnel passing below the gasket 14. It is connected to a supply unit 25 provided on the lower side in the vicinity of the hydrogen outlet 16 via a passage 25a. Gaskets 26a and 27a are provided between the separators 4a and 4c so as to surround the discharge unit 24 and the supply unit 25, respectively.
And the supply part 25 is sealed.

A water passage 28 is formed in the contact portion of the separator 4b, which is the upper surface in FIG. 2, with the porous guide body 10. One side 28a of the water passage 28 is communicated with a discharge portion 29 provided on the right side in the vicinity of the oxygen inlet portion 19 through a tunnel passage 29a passing below the gasket 14, and the other 28b is a tunnel passage passing below the gasket 14. It is connected to a supply unit 30 provided on the left side in the vicinity of the oxygen outlet unit 20 via 30a. Gaskets 26b and 27b are provided between the separators 4a and 4b so as to surround the discharge unit 29 and the supply unit 30, respectively.
Also, the supply unit 30 is sealed.

Therefore, when heated and humidified hydrogen is supplied from the hydrogen inlet portion 15 of the battery cell stack 3, the hydrogen containing water passes from the inlet passage 15a through the tunnel passage 15b to the distribution passage 15c of the battery cell 6. It is introduced and flows through the reaction gas passage 13 from the distribution passage 15c. On the other hand, when oxygen that has been heated and humidified is supplied from the oxygen inlet portion 19, the oxygen containing the moisture is supplied from the inlet passage 19a to the tunnel passage 19b.
To the distribution passage 19c of the battery cell 6, and flows from the distribution passage 19c to the reaction gas passage 12.

At this time, the battery cell 6 generates electricity by electrochemically reacting hydrogen and oxygen of the reaction gas with each other, and the change in free energy at that time is taken out as electric energy to generate electricity. The battery cells 6 are connected in series with the adjacent battery cells 6 via the separator 4c, and the generated electric power is taken out from a current collecting unit (not shown) provided at both ends of the battery cell stack 3.

Hydrogen and water are mainly collected in the collecting passage 16c of the battery cell 6, pass through the tunnel passage 16b, are guided to the outlet passage 16a, and are discharged from the outlet portion 16. Mainly oxygen and water are collected in the collecting passage 20c of the battery cell 6,
It is guided to the exit passage 20a through the tunnel passage 20b and discharged from the exit portion 20.

On the other hand, the electrochemical reaction of hydrogen and oxygen by the battery cell 6 is such that oxygen and water are mixed in the porous guide body 10,
On the other hand, hydrogen and water are supplied to the surface of the ion exchange membrane 7 through the positive catalyst electrode 8, and hydrogen and water are supplied to the surface of the ion exchange membrane 7 through the porous guide body 11 and the negative catalyst electrode 9. It is performed at the interface between the catalyst electrode 8 and the ion exchange membrane 7 and at the interface between the negative catalyst electrode 9 and the ion exchange membrane 7. Since the elongation of the ion exchange membrane 7 greatly changes depending on the water content, it is necessary to always keep the humidification level of the ion exchange membrane 7 appropriate to keep the elongation of the ion exchange membrane 7 constant and keep the interface stable. .

Electricity is generated by the electrochemical reaction of hydrogen and oxygen of the reaction gas by the battery cell 6, and water is generated at that time, but not only the expansion due to the relative humidity inside the battery cell 6, Excess water such as condensed water, generated water, and excess supply water generated inside directly further contacts the ion-exchange membrane 7 to further expand and deteriorate the performance of the battery cell 6. However, the catalyst electrodes 8 on both sides of the battery cell 6, 9 Porous guide body 10, 1
1 are arranged in contact with each other, and excess water such as condensed water, generated water, and excess supply water generated inside the battery cell 6 can be absorbed and removed by the porous guide bodies 10 and 11.

Therefore, the expansion of the ion exchange membrane 7 can be prevented, the performance of the battery cell 6 can be maintained at high efficiency for a long period of time, and the diffusibility of the reaction gas can be prevented. Thus, excess water can be removed without using a special device, and the device can be simple, low-priced, compact and lightweight. By forming the reaction gas passages 12 and 13 with the porous guide bodies 10 and 11, when water is supplied, they are absorbed by the porous guide bodies 10 and 11 and partly diffuses into the reaction gas passages 12 and 13 and partly. By directly moving to the catalyst electrodes 8 and 9, the humidification is effectively performed, and when excessive water is generated, there is a damper effect of absorbing the excessive water and supplying it when insufficient, so that an appropriate amount of humidification is possible.

As described above, in this embodiment, the battery cell 6
Is held by separators 4a, 4b and 4c joined together through a gasket 14 which is a sealing member, and an inlet passage 15a of a hydrogen reaction gas passage formed in the separator 4b in the stacking direction is connected to a battery via a tunnel passage 15b. The reaction gas passage 13 of the cell 6 is communicated, and the outlet passage 16a of the reaction gas passage is communicated with the reaction gas passage 13 of the battery cell 6 via the tunnel passage 16b. The inlet passage 19a of the oxygen reaction gas passage formed in the separator 4b in the stacking direction is communicated with the reaction gas passage 12 of the battery cell 6 through the tunnel passage 19b, and the outlet passage 20a of the reaction gas passage is the tunnel passage. It communicates with the reaction gas passage 12 of the battery cell 6 via 20b. The tunnel passages 15b, 16b, 19b, 20b are formed by straddling the gasket 14 in a tunnel shape.
When a structure is adopted in which the battery cells 6 are held by the separators 4a, 4b, 4c joined together via 4, it is not necessary to provide a reaction gas passage on the sealing surface, and the sealing surface can be made flat. The property is improved.

Further, in this embodiment, the surface direction of the battery cells 6 is oriented vertically, and the arrangement direction L2 of the battery cells 6 is inclined with respect to the installation direction L1 of the battery cell stack 3, and the reaction gas passage is provided. 12 and 13 are inclined. Therefore, by simply installing the fuel cell 1 horizontally, the reaction gas passages 12 and 13 will be in an oblique state, and the water of the battery cells 6 can be discharged without using a special device. Excellent stability without the use of fixtures and easy drainage.

The installation direction L1 of the battery cell stack 3
Since the arrangement direction L2 of the battery cell 6 is inclined with respect to the battery cell stack 3, a large space is secured between the battery cell stack 3 and the battery cell 6 at four corners of the battery cell stack 3, and
A large space for providing the reaction gas outlets 16 and 20 and the water discharge portions 25 and 30 is provided in the lower corner of the space, the water discharge portion can be easily secured, and the size can be reduced.

FIG. 5 is a schematic view showing the schematic constitution of an embodiment of the fuel cell according to claim 3. Fuel Cell 1 of this Example
The same components as those in the embodiments of FIGS. 1 to 4 are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the surface direction of the battery cells 6 of the fuel cell 1 is oriented in the vertical direction, and the arrangement direction L2 of the battery cells 6 is inclined with respect to the installation direction L1 of the battery cell stack 3. The reaction gas inlets 15 and 19 are provided at the upper corners of the battery cell stack 3, and the reaction gas outlets 16 and 20 are provided at the lower corners. The reaction gas outlets 16 and 20 are provided below the lower portion L3 of the battery cell 6, and the generated water and excess water of the battery cell 6 can be easily drained, and the reliability is improved. In addition, it does not require a special device, is inexpensive, lightweight, and compact, and can be used over the entire surface without the battery cell submerged in water, enabling highly efficient power generation.

FIG. 6 is a schematic view showing the schematic constitution of another embodiment of the fuel cell according to claim 3. In the fuel cell 1 of this embodiment, the same components as those of the embodiment of FIGS. 1 to 4 are designated by the same reference numerals and the description thereof will be omitted. Also in this example,
The plane direction of the battery cells 6 of the fuel cell 1 is oriented vertically, and the arrangement direction L2 of the battery cells 6 is inclined with respect to the installation direction L1 of the battery cell stack 3. The reaction gas inlets 15 and 19 are provided at the upper corners of the battery cell stack 3, and the reaction gas outlets 16 and 20 are provided at the lower corners. The reaction gas outlet 20 is provided below the lower portion L3 of the battery cell 6. Further, a drainage passage 50 communicating with the battery cell 6 is provided, and the generated water or excess water is discharged to the water tank 51 from this drainage passage 50. The water accumulated in the water tank 51 is sent to the humidifying section 53 by driving the pump 52,
The humidifying section 53 mixes hydrogen and oxygen of the reaction gas with each other and supplies the hydrogen and oxygen from the reaction gas inlets 15 and 19.

As described above, the generated water and excess water of the battery cell 6 can be easily drained, the reliability is improved, and the produced water and excess water are recovered and reused, so that they are inexpensive, lightweight and compact. Therefore, the battery cells can be used over the entire surface without being submerged in water and highly efficient power generation is possible.

[0035]

As described above, according to the invention of claim 1, the battery cell is held by the separator joined through the seal member, and the reaction gas passage formed in the stacking direction on the separator and the battery cell. Since the tunnel passage communicating with the seal member is formed in a tunnel shape, the reaction gas passage is formed on the seal surface when the battery cell is held by the separator joined via the seal member. Since it is not provided, the sealing surface can be made flat and the sealing performance is improved.

According to the second aspect of the invention, the surface direction of the battery cells is oriented vertically, and the arrangement direction of the battery cells is inclined with respect to the installation direction of the battery cell stack, and the reaction gas passage is inclined. By simply installing the fuel cell horizontally, the reaction gas passage will be in an oblique state and the water in the battery cell can be drained without using a special device, and no tilting stand or fixture is used. It has excellent stability and is easy to drain. In addition, by arranging the battery cell stack incliningly with respect to the installation direction of the battery cell stack, a large space for providing a water discharge part can be provided in the battery cell stack, and it is easy to secure the water discharge part and is small in size. Is possible.

According to the third aspect of the present invention, since the surface direction of the battery cells is oriented in the vertical direction and the outlet of the reaction gas is provided below the battery cells of the battery cell stack, the generated water of the battery cells and excess water are formed. Drainage is simple and reliability is improved.
In addition, it requires no special equipment, is cheap, lightweight, and compact.
The battery cells can be used over the entire surface without being submerged in water, and highly efficient power generation is possible.

[Brief description of drawings]

FIG. 1 is a front view of a fuel cell according to claim 1 and claim 2.

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

3 is a cross-sectional view taken along line XX and YY of FIG.

FIG. 4 is a perspective view showing an embodiment of a fuel cell.

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

FIG. 6 is a schematic 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 4a, 4b, 4c Separator 6 Battery Cell 7 Ion Exchange Membrane 8, 9 Catalyst Electrode 12, 13 Reactive Gas Passage 14 Gasket 15b, 16b, 19b, 20b Tunnel Passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yu Mizuno 2500 Shin-kai, Iwata, Shizuoka Prefecture Yamaha Motor Co., Ltd.

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 joined through a seal member, and a tunnel passage that connects the battery cell and the reaction gas passage formed in the stacking direction to the separator is formed into a tunnel shape with the seal member. A fuel cell, which is formed by straddling. 2. A battery cell stack having battery cells having a positive catalyst electrode on one surface of the ion exchange membrane and a negative catalyst electrode on the other surface thereof, and a reaction gas passage of each of the battery cells. In a fuel cell in which gas is supplied and electricity is generated by the reaction of this reaction gas, the surface direction of the battery cells is oriented vertically and the arrangement direction of the battery cells is inclined with respect to the installation direction of the battery cell stack. The fuel cell is characterized in that the reaction gas passage is inclined. 3. A battery cell stack having battery cells having a positive catalyst electrode on one surface of the ion exchange membrane and a negative catalyst electrode on the other surface thereof, and a reaction gas passage of each of the battery cells. In a fuel cell in which gas is supplied and electricity is generated by the reaction of the reaction gas, the surface direction of the battery cell is oriented in the vertical direction, and an outlet portion of the reaction gas is provided at a position lower than the battery cell of the battery cell stack. A fuel cell characterized by being provided.