CN110931821B

CN110931821B - Gasket for fuel cell

Info

Publication number: CN110931821B
Application number: CN201910880180.XA
Authority: CN
Inventors: 白川创平
Original assignee: Nok Corp
Current assignee: Nok Corp
Priority date: 2018-09-19
Filing date: 2019-09-18
Publication date: 2022-11-18
Anticipated expiration: 2039-09-18
Also published as: CN110931821A; JP7075321B2; JP2020047472A

Abstract

The invention provides a battery gasket for fuel. The cell gasket for fuel seals between an electrolyte membrane and a separator, and includes an anode-side gasket and a cathode-side gasket. The two gaskets are respectively provided integrally with a lip-shaped seal portion and a sub-seal portion having a height lower than that of the lip-shaped seal portion. The lip seal on the anode side is disposed at a position that overlaps the secondary seal on the cathode side in a plane, and the lip seal on the cathode side is disposed at a position that overlaps the secondary seal on the anode side in a plane. The secondary seal portion has an inclined surface inclined in a direction in which the height gradually increases as the secondary seal portion moves away from the lip seal portion, and a reaction force receiving portion is provided at the top of the inclined surface.

Description

Gasket for fuel cell

Technical Field

The present invention relates to a gasket for a fuel cell.

Background

In a stack used for a fuel cell, a plurality of power generation cells having separators are stacked. Fuel and cooling water flow between the anode and the cathode across the electrodes on the reaction surfaces inside the power generation cell. Therefore, it is necessary to seal hydrogen, oxygen, and cooling water between the anode and the cathode.

Since the sealing between the anode and the cathode needs to generate a surface pressure (seal surface pressure), the sealing function is satisfied by mounting the anode-side gasket 11 and the cathode-side gasket 21 having the

lip seals

11 and 22, as shown in fig. 9 a.

However, in this configuration, as shown in fig. 9 (B), when a positional deviation a occurs between the

gaskets

11 and 21 on the plane between the anode and the cathode, there is a possibility that the sealing function cannot be achieved because no surface pressure is generated and the electrolyte membrane 51 is greatly deformed.

In order to solve this problem, as shown in fig. 10, a flat gasket having a flat seal portion 23 is proposed as one of the anode-side gasket 11 and the cathode-side gasket 21 (in the figure, the cathode-side gasket 21), instead of the lip gasket having the lip seal portion 22. According to this configuration, since the wide flat seal portion 23 faces the lip seal portion 12, the surface pressure can be generated even if the positional displacement occurs between the

gaskets

11 and 21.

However, in this configuration, there is a fear that: since the contact area of the flat gasket 21 with respect to the electrolyte membrane 51 is increased, the surface pressure is dispersed, and a necessary peak surface pressure cannot be secured, thereby deteriorating the sealing function.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2004-303723

Patent document 2: japanese patent laid-open No. 2008-97899

Disclosure of Invention

Technical problem to be solved by the invention

To solve this problem, as shown in fig. 11 (a) and (B), it is proposed that the anode-side gasket 11 and the cathode-side gasket 21 are formed in a shape having lip-

shaped sealing portions

12 and 22 and flat sealing

portions

13 and 23, respectively, integrally therewith. According to this configuration, even if the surface pressure is somewhat dispersed, since the plurality of

lip seal portions

12 and 22 are provided, the sealing function can be realized in both the

lip seal portions

12 and 22.

This structure has room for improvement in the following respects.

The dimensional tolerances of the height of the

gaskets

11, 21 need to be taken into account. When the

flat seal portions

13 and 23 are high in height, the

gaskets

11 and 21 are extremely compressed at the time of stack assembly, and therefore a large reaction force is generated in the

gaskets

11 and 21.

The invention provides a gasket for a fuel cell, which is not easy to form a high compression state and generate a large reaction force when a stack is assembled.

Means for solving the problems

One aspect of the present invention is a gasket for a fuel cell, which seals between an electrolyte membrane and a pair of separators disposed on both sides in a thickness direction of the electrolyte membrane, the gasket for a fuel cell including: an anode-side gasket held by one of the separators and integrally having a lip seal portion that is in contact with one surface of the electrolyte membrane and a sub-seal portion; the secondary seal has a height lower than the lip seal; a cathode-side gasket that is held by the other separator, and that integrally includes a lip seal portion and a sub-seal portion, the lip seal portion being disposed at a position that overlaps the sub-seal portion and the lip seal portion of the anode-side gasket in a planar manner, and being in contact with the other surface of the electrolyte membrane; the secondary seal being of a lower height than the lip seal; an inclined surface provided on at least one of the two sub seal portions and inclined in a direction in which a height thereof gradually increases as it becomes farther from the integrally provided lip seal portion; and a reaction force receiving part provided at a top of the inclined surface.

Effects of the invention

According to the present invention, since the sub-seal portion having the inclined surface and the reaction force receiving portion is provided, the gasket is easily elastically deformed when a compression load is applied to the gasket at the time of stack assembly, and is not easily brought into a high compression state. Therefore, a large reaction force is not generated in the gasket, and the reaction force can be reduced.

This allows the height of the secondary seal portion to be set to be somewhat large when reduction of the reaction force (low reaction force) is achieved. Therefore, it is possible to avoid a situation in which the surface pressure does not occur in the lip seal portion on the opposite side due to the insufficient height of the sub seal portion, and it is possible to ensure the sealing property.

Drawings

Fig. 1 is a main portion sectional view of a gasket of embodiment 1;

fig. 2 is a main portion sectional view showing a state where a compression load is applied to the gasket;

fig. 3 is a graph showing the reaction force characteristic of the above-described gasket;

fig. 4 is a graph showing the surface pressure characteristics of the gasket;

fig. 5 is a main portion sectional view of the gasket of embodiment 2;

FIG. 6 is a main portion sectional view of a gasket of the embodiment 3;

FIG. 7 is a main portion sectional view of a gasket of the 4 th embodiment;

FIG. 8 is a main portion sectional view of a gasket of the 5 th embodiment;

fig. 9 is a main portion sectional view of a gasket of a reference example;

FIG. 10 is a main portion sectional view of a gasket of another reference example;

fig. 11 is a main portion sectional view of a gasket of another reference example.

Detailed Description

[ embodiment 1 ]

As shown in fig. 1, the gasket of the present embodiment is used as a gasket for a fuel cell. The gasket for a fuel cell has a sealing function between the electrolyte membrane 51 or a frame holding the electrolyte membrane 51 and the pair of

separators

31 and 41 disposed on both sides in the thickness direction thereof, and seals a sealing fluid such as hydrogen, oxygen, or cooling water in the cell interior I so as not to leak to the cell exterior O.

The gasket for a fuel cell is configured by combining an anode-side gasket 11 and a cathode-side gasket 21, the anode-side gasket 11 being bonded and held to one of the separators 31 and being in contact with one of the surfaces 51a of the electrolyte membrane 51 or the frame; the cathode-side gasket 21 is bonded and held to the other separator 41, and is in contact with the electrolyte membrane 51 or the other surface 51b of the frame. The

gaskets

11, 21 are disposed around the cell reaction surfaces, around the cell manifolds, and the like. The

gaskets

11 and 21 are formed of a predetermined rubber-like elastic material.

The anode-side gasket 11 integrally has: a lip seal portion 12 as a main lip, provided with a seal lip having a mountain-shaped cross section; and a sub-seal portion 14 disposed on the battery outer O side of the lip seal portion 12, wherein the lip seal portion 12 and the sub-seal portion 14 are arranged in parallel in the gasket width direction. In this gasket for a fuel cell, the flat sealing portion having a flat surface in the above-described conventional art is not provided, but the sub-sealing portion 14 is provided instead of the flat sealing portion.

The sub seal portion 14 has, in plan: an inclined surface 15 provided so as to be inclined in a direction in which the height dimension gradually increases as it goes away from the lip seal 12; and a reaction force receiving portion 16 provided at the top (highest height position) of the inclined surface 15 and having an arc-shaped cross section. The inclined surface 15 and the reaction receiving portion 16 are provided over the entire length of the sub seal portion 14, that is, the entire length of the gasket 11. The height dimension of the secondary seal portion 14 is formed lower than the height dimension of the lip seal portion 12. The side surface 17 of the sub seal portion 14 opposite to the lip seal portion 12 is formed as a vertical surface-like side surface standing up at a right angle from the diaphragm 31.

The cathode-side gasket 21 integrally has: the sub seal portion 24; and a lip seal 22 as a main lip, which is disposed on the battery outer side O of the sub seal 24 and has a seal lip with a mountain-shaped cross section, and these sub seal 24 and lip seal 22 are disposed in parallel in the gasket width direction. In this gasket for a fuel cell, the flat sealing portion having a flat surface in the above-described conventional art is not provided, but the sub-sealing portion 24 is provided instead of the flat sealing portion.

The sub seal portion 24 has: an inclined surface 25 provided so as to be inclined in a direction in which the height dimension gradually increases as it goes away from the lip seal portion 22; and a reaction force receiving portion 26 provided at the top (highest height position) of the inclined surface 25 and having an arc-shaped cross section. The inclined surface 25 and the reaction force receiving portion 26 are provided over the entire length of the sub seal portion 24, that is, the entire length of the gasket 21. The height dimension of the secondary seal 24 is formed lower than the height dimension of the lip seal 22. The side surface 27 of the sub seal portion 24 opposite to the lip seal portion 22 is formed as a vertical surface-like side surface which stands up at a right angle from the diaphragm 41.

The lip seal portion 12 of the anode-side gasket 11 is disposed at a position where the lip tip overlaps the inclined surface 25 of the secondary seal portion 24 of the cathode-side gasket 21 on the plane.

The lip seal portion 22 of the cathode-side gasket 21 is disposed at a position where the lip tip overlaps the inclined surface 15 of the secondary seal portion 14 of the anode-side gasket 11 on the plane.

When the fuel cell gasket having the above-described configuration is assembled into a stack and a compressive load is applied to the gasket, as shown in fig. 2, in the anode gasket 11 and the cathode gasket 21, the lip tips of the

lip seals

12 and 22 are in contact with the electrolyte membrane 51 or the frame, respectively, and the reaction

force receiving portions

16 and 26 of the

sub-seals

14 and 24 are in contact with the electrolyte membrane 51 or the frame, respectively, the

inclined surfaces

15 and 25 of the

sub-seals

14 and 24 are in a state where only a part near the reaction

force receiving portions

16 and 26 is in contact with the electrolyte membrane 51 or the frame and the other part is not in contact with the electrolyte membrane 51 or the frame, and the

gap spaces

18 and 28 are formed between the

inclined surfaces

15 and 25 and the electrolyte membrane 51 or the frame.

Therefore, the

gap spaces

18 and 28 can be used as escape spaces for the rubber material, and the

sub seal portions

14 and 24 are easily elastically deformed and are not easily put into a high compression state, so that large reaction force is not generated in the

entire gaskets

11 and 21, and the magnitude of the generated reaction force can be reduced. As for the result of the comparison test, as shown in the graph of fig. 3, it can be confirmed that: the reaction force is sufficiently reduced as compared with the case where the

flat seal portions

13 and 23 are provided (see fig. 11, comparative example).

On the other hand, since the

sub-seal portions

14 and 24 are in contact with the electrolyte membrane 51 or the frame body in the narrow range formed by the reaction

force receiving portions

16 and 26, the magnitude of the generated peak surface pressure is substantially equal to that of the comparative example as shown in the graph of fig. 4. Therefore, the sealing performance can be exhibited also in the

sub-seal portions

14 and 24.

In addition, when the reduction of the reaction force (low reaction force) is achieved as described above, it is permissible to set the height dimension of the

sub seal portions

14, 24 to be somewhat large. Therefore, it is possible to avoid a situation in which the surface pressure is not generated in the

lip seal portions

12 and 22 on the opposite side due to the insufficient height dimension of the

sub seal portions

14 and 24, and thus it is possible to ensure the sealing performance of the entire gasket.

In this embodiment, the

inclined surfaces

15 and 25 and the reaction

force receiving surfaces

16 and 26 are provided in both the sub-seal portion 14 of the anode-side gasket 11 and the sub-seal portion 24 of the cathode-side gasket 21, but the

inclined surfaces

15 and 25 and the reaction

force receiving surfaces

16 and 26 may be provided in only one of the

sub-seal portions

14 and 24.

The

sub-seal portions

14 and 24 may have the following configurations.

[ 2 nd embodiment ]

In the example shown in fig. 5, in addition to the configuration of embodiment 1, in order to adjust the magnitude of the generated reaction force, recesses 19 and 29 are provided in portions of the

inclined surfaces

15 and 25 of the

sub-seal portions

14 and 24. The

recesses

19, 29 are formed as grooves extending in the longitudinal direction of the

sub-seal portions

14, 24. The

concave portions

19 and 29 are formed in circular arc shapes in cross section. A plurality of

recesses

19 and 29 may be provided. Instead of the

recesses

19 and 29, a projection (not shown) may be provided, or a projection (not shown) may be provided together with the

recesses

19 and 29. In this case, the convex portion is formed as a ridge extending in the longitudinal direction of the

sub-seal portions

14, 24. The cross-sectional shape of the convex part is circular arc. The projection may be provided in plural.

[ embodiment 3 ]

In the example shown in fig. 6, in order to adjust the magnitude of the generated reaction force, the side surfaces 17, 27 of the

sub seal portions

14, 24 on the opposite side to the

lip seal portions

12, 22 are formed as inclined surface-like side surfaces which are inclined in a direction in which the height dimension becomes smaller as the distance from the

lip seal portions

12, 22 becomes larger. Therefore, when the side surfaces 17 and 27 of the

sub seal portions

14 and 24 are formed in an inclined plane, the reaction

force receiving portions

16 and 26 are less likely to fall down toward the side surfaces 17 and 27.

[ 4 th embodiment ]

In the example of fig. 7, to adjust the magnitude of the generated reaction force,

flat portions

20, 30 having flat surfaces are provided between the lip seals 12, 22 and the sub-seals 14, 24. When the

flat portions

20 and 30 are provided in the case where the full width of the

gaskets

11 and 21 is constant, the widths of the

sub seal portions

14 and 24 are reduced, and accordingly, the inclination angles of the

inclined surfaces

15 and 25 are increased.

[ 5 th embodiment ]

In the example of fig. 8,

flat portions

20 and 30 having flat surfaces are provided between the

lip seal portions

12 and 22 and the

sub seal portions

14 and 24 to adjust the magnitude of the generated reaction force, as in the case of the above-described embodiment 4. When the

flat portions

20 and 30 are provided in the case where the full width of the

gaskets

11 and 21 is constant, the widths of the

sub seal portions

14 and 24 are reduced, and accordingly, the inclination angles of the

inclined surfaces

15 and 25 are increased. Further, the

flat portions

20 and 30 are provided with

recesses

19 and 29 or protrusions on a part of the flat surface, as in the above-described embodiment 2.

In the gaskets of the above-described embodiments 2 to 5, as in the gasket of embodiment 1, the

sub-seal portions

14 and 24 having the

inclined surfaces

15 and 25 and the reaction

force receiving portions

16 and 26 are provided, and the

gap spaces

18 and 28 are further formed, so that the magnitude of the generated reaction force can be reduced, and the sealing function can be realized even at the time of low compression. Further, since the

recesses

19 and 29, the projections, the inclined planar side surfaces 17 and 27, the

flat portions

20 and 30, and the like are provided, the magnitude and distribution of the generated reaction force, the contact posture of the

gaskets

11 and 21 with respect to the electrolyte membrane 51 or the frame body, and the like can be finely adjusted.

The material (rubber material) of the

gaskets

11 and 21 is preferably a silicon material, an EPDM material, a fluorine material, or the like, but is not limited thereto. As the frame, a frame having a Young's modulus of substantially 3GPa or more and a thickness of about 250 μm (on both sides of the MEA) is preferably used. As the material of the frame body, PEN, POM, PPS, or the like can be used.

Description of reference numerals

11. Anode side gasket

12. 22 lip seal

14. 24 pairs of sealing parts

15. 25 inclined plane

16. 26 reaction force receiving part

17. 27 side surface

18. 28 space of gap

19. 29 recess

20. 30 flat part

21. Cathode side gasket

31. 41 diaphragm

51. Electrolyte membrane

Inside of the battery

Outside of the O cell

Claims

1. A gasket for a fuel cell, which seals between an electrolyte membrane and a pair of separators disposed on both sides in a thickness direction of the electrolyte membrane, the gasket for a fuel cell comprising:

an anode-side gasket held by one of the separators and integrally having a lip seal portion that is in contact with one surface of the electrolyte membrane and a sub-seal portion; the secondary seal being of a lower height than the lip seal;

a cathode-side gasket that is held by the other separator, and that integrally includes a lip seal portion and a sub-seal portion, the lip seal portion being disposed at a position that overlaps the sub-seal portion and the lip seal portion of the anode-side gasket in a planar manner, and being in contact with the other surface of the electrolyte membrane; the secondary seal being of a lower height than the lip seal;

inclined surfaces provided on both of the two sub seal portions and inclined in a direction in which a height thereof gradually increases as the inclined surfaces are separated from the integrally provided lip seal portions; and

and a reaction force receiving part provided at a top of the inclined surface.

2. The gasket for a fuel cell according to claim 1,

a recess is provided in a part of the inclined surface.

3. The gasket for a fuel cell according to claim 1,

a projection is provided on a part of the inclined surface.

4. The gasket for fuel cells according to claim 1,

the side face of the secondary seal portion on the side opposite to the lip seal portion has an inclined face shape inclined in a direction in which the height gradually decreases with distance from the lip seal portion.

5. The gasket for a fuel cell according to claim 1,

the lip seal and the secondary seal have a flat portion therebetween.

6. The gasket for fuel cells according to claim 5,

a recess is provided in a part of the flat portion.

7. The gasket for a fuel cell according to claim 5,

a projection is provided at a part of the flat portion.