JP7075321B2 - Fuel cell gasket - Google Patents

Description

The present invention relates to a fuel cell gasket according to a sealing technique.

In the stack used for the fuel cell, a plurality of power generation cells provided with a separator are stacked. On the reaction surface inside the power generation cell, fuel and cooling water flow between the anode and the cathode with the electrodes sandwiched between them. Therefore, it is necessary to seal hydrogen, oxygen and cooling water between the anode and the cathode.

Since the seal between the anode and the cathode needs to generate a surface pressure (seal surface pressure), the anode side gasket 11 and the cathode side gasket 21 having the lip-shaped seals 12 and 22 are provided as shown in FIG. 9 (A). By installing it, the sealing function is satisfied.

However, in this configuration, as shown in FIG. 9B, when the gaskets 11 and 21 have a positional deviation a on a plane between the anode and the cathode, the sealing function is not performed because the surface pressure is not generated. In addition, there is a concern that the electrolyte membrane 51 may be significantly deformed.

In order to solve this problem, as shown in FIG. 10, one of the anode side gasket 11 and the cathode side gasket 21 (cathode side gasket 21 in the figure) is not a lip type gasket provided with a lip shape seal 22 but a flat shape. It has been proposed to use a flat type gasket with a seal 23. According to this configuration, since the wide flat seal 23 faces the lip-shaped seal 12, surface pressure can be generated even if the gaskets 11 and 21 are misaligned with each other.

However, in this configuration, since the contact area of the flat type gasket 21 with respect to the electrolyte membrane 51 increases, there is a concern that the surface pressure will be dispersed, the required peak surface pressure will not be secured, and the sealing function will deteriorate.

Japanese Unexamined Patent Publication No. 2004-303723 Japanese Unexamined Patent Publication No. 2008-97899

In order to solve this problem, as shown in FIGS. 11A and 11B, the anode-side gasket 11 and the cathode-side gasket 21 are integrally provided with lip-shaped seals 12, 22 and flat-shaped seals 13, 23, respectively. It is proposed to do. According to this configuration, since a plurality of lip-shaped seals 12 and 22 are provided even if the surface pressure is slightly dispersed, each of the lip-shaped seals 12 and 22 can fulfill the sealing function, respectively.

However, there is room for improvement in this configuration in the following points.

That is, it is necessary to consider the dimensional tolerance of the heights of the gaskets 11 and 21. If the heights of the flat seals 13 and 23 are large, the gaskets 11 and 21 are in an extremely high compression state when the stack is assembled, so that a large reaction force is generated on the gaskets 11 and 21. Therefore, there is a concern that the electrolyte membrane 51 may be deformed or damaged due to this large reaction force.

An object of the present invention is to provide a gasket for a fuel cell, which is unlikely to be in a highly compressed state during stack assembly, and thus does not generate a large reaction force and can reduce the reaction force.

In order to solve the above problems, the fuel cell gasket of the present invention is a fuel cell gasket that seals between the anode film or the frame holding the anode film and a pair of separators arranged on both sides in the thickness direction thereof. The anode-side gasket, which is held by one of the separators and contacts one surface of the electrolyte membrane or the frame, and is held by the other separator and contacts the other surface of the electrolyte membrane or the frame. The anode-side gasket and the cathode-side gasket are integrally provided with a lip-shaped seal and a sub-seal having a height smaller than the lip-shaped seal, respectively, and the lip-shaped seal of the anode-side gasket is the cathode. The lip-shaped seal of the cathode side gasket is arranged at a position where it overlaps the sub-seal of the side gasket in a plane, and the lip-shaped seal of the cathode side gasket is arranged at a position where the sub-seal of the anode side gasket overlaps with the sub-seal of the anode side. The gasket sub-seal is characterized by comprising an inclined surface provided so as to incline in a direction in which the height gradually increases as the distance from the lip-shaped seal increases, and a reaction force receiving portion provided on the top of the inclined surface. And.

Further, as an embodiment, the fuel cell gasket described above is characterized in that a concave portion or a convex portion is provided in a part of the inclined surface.

Further, as an embodiment, in the above-described fuel cell gasket, the side surface of the sub-seal opposite to the lip-shaped seal is an inclined surface whose height gradually decreases as the distance from the lip-shaped seal increases. It is characterized in that it is formed in a shape.

Further, as an embodiment, the fuel cell gasket described above is characterized in that a flat portion is provided between the lip-shaped seal and the sub-seal.

Furthermore, as an embodiment, the fuel cell gasket described above is characterized in that a concave portion or a convex portion is provided in a part of the flat portion.

In the present invention, since the sub-seal having an inclined surface and a reaction force receiving portion is provided instead of the flat seal by the above configuration, the gasket is easily elastically deformed when a compressive load is applied to the gasket during stack assembly. It is hard to be in a compressed state. Therefore, a large reaction force is not generated in the gasket, and the reaction force can be reduced.

Further, when the reaction force is reduced in this way, it is permissible to set the height of the subseal to a certain extent. Therefore, it is possible to avoid a situation in which the height of the sub-seal is insufficient and no surface pressure is generated on the lip-shaped seal on the opposite side, so that the sealing property can be ensured.

Cross-sectional view of the main part of the gasket according to the first embodiment Cross-sectional view of the main part showing the state where the compressive load is input to the gasket. Graph diagram showing the reaction force characteristics of the gasket Graph diagram showing the surface pressure characteristics of the gasket Cross-sectional view of the main part of the gasket according to the second embodiment Cross-sectional view of the main part of the gasket according to the third embodiment Cross-sectional view of the main part of the gasket according to the fourth embodiment Cross-sectional view of the main part of the gasket according to the fifth embodiment Cross-sectional view of the main part of the gasket according to the conventional example Cross-sectional view of the main part of the gasket according to another conventional example Cross-sectional view of the main part of the gasket according to another conventional example

First embodiment ...
As shown in FIG. 1, the gasket according to the embodiment is used as a gasket for a fuel cell. The fuel cell gasket exerts a sealing function between the electrolyte membrane 51 or a frame (not shown) holding the electrolyte membrane 51 and a pair of separators 31 and 41 arranged on both sides in the thickness direction thereof, and exhibits a sealing function in the cell inside I. This sealing fluid is sealed so that the sealing fluid such as hydrogen, oxygen or cooling water does not leak to the outside O of the cell.

The fuel cell gasket is adhered and held to one separator 31 and is adhered to and held by the anode side gasket 11 which is in contact with the electrolyte membrane 51 or one surface 51a of the frame, and is adhered and held by the other separator 41. It is composed of a combination with a cathode side gasket 21 that contacts the 51 or the other surface 51b of the frame. Gaskets 11 and 21 are arranged around the cell reaction surface, around the cell manifold, and the like. The gaskets 11 and 21 are formed of a predetermined rubber-like elastic body.

The anode-side gasket 11 integrally includes a lip-shaped seal 12 as a main lip provided with a seal lip having a chevron cross section, and a sub-seal 14 arranged on the O side outside the cell, and these lip-shaped seals 12 and the sub-seal 14 are provided. Are provided side by side in the gasket width direction. The fuel cell gasket is not provided with a flat seal having a flat surface on a flat surface in the prior art, and is provided with a sub-seal 14 instead of the flat seal.

The sub-seal 14 is provided on an inclined surface 15 provided so as to incline in a direction in which the height dimension gradually increases as the distance from the lip-shaped seal 12 increases, and on the top portion (the portion having the highest height position) of the inclined surface 15. A reaction force receiving portion 16 having an arcuate cross section is provided on a plane. The inclined surface 15 and the reaction force receiving portion 16 are provided over the entire length of the sub-seal 14, that is, the entire length of the gasket 11. The height dimension of the sub-seal 14 is formed to be smaller than the height dimension of the lip-shaped seal 12. The side surface 17 of the sub-seal 14 opposite to the lip-shaped seal 12 is a vertical surface-like side surface that rises at a right angle from the separator 31.

The cathode side gasket 21 integrally includes a sub-seal 24 and a lip-shaped seal 22 as a main lip arranged on the O side outside the cell and provided with a seal lip having a chevron cross section, and these sub-seals 24 and the lip-shaped seal 22 are provided. Are provided side by side in the gasket width direction. The fuel cell gasket is not provided with a flat seal having a flat surface on a flat surface in the prior art, and is provided with a sub-seal 24 instead of the flat seal.

The sub-seal 24 is provided on an inclined surface 25 provided so as to incline in a direction in which the height dimension gradually increases as the distance from the lip-shaped seal 22 increases, and on the top of the inclined surface 25 (the portion having the highest height position). It is provided with a reaction force receiving portion 26 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 24, that is, the entire length of the gasket 21. The height dimension of the sub-seal 24 is formed to be smaller than the height dimension of the lip-shaped seal 22. The side surface 27 of the sub-seal 24 opposite to the lip-shaped seal 22 is a vertical surface-like side surface that rises at a right angle from the separator 41.

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

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

When the fuel cell gasket having the above configuration is assembled as a stack and a compressive load is applied to the gasket, the lip tips of the lip-shaped seals 12 and 22 are applied to the anode side gasket 11 and the cathode side gasket 21, respectively, as shown in FIG. Is in contact with the electrolyte membrane 51 or the frame, and the reaction force receiving portions 16 and 26 of the subseals 14 and 24 are in contact with the electrolyte membrane 51 or the frame, and the inclined surfaces 15 and 25 of the subseals 14 and 24 are the reaction force receiving portions 16. , 26 Only a part of the vicinity 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 between the inclined surfaces 15, 25 and the electrolyte membrane 51 or the frame. Gap spaces 18 and 28 are formed.

Therefore, the gap spaces 18 and 28 can be used as escape spaces for the rubber material, and the sub-seals 14 and 24 are easily elastically deformed and are unlikely to be in a highly compressed state. Therefore, the gaskets 11 and 21 as a whole have a large reaction force. Is not generated, and the magnitude of the generated reaction force can be reduced. As a result of the comparative test, as shown in the graph of FIG. 3, it was confirmed that the reaction force was sufficiently reduced as compared with the case where the flat seals 13 and 23 were provided (see FIG. 11, comparative example). ing.

On the other hand, since the sub-seals 14 and 24 come into contact with the electrolyte membrane 51 or the frame in a narrow range due to the reaction force receiving portions 16 and 26, the amount of peak surface pressure generated is large as shown in the graph of FIG. The pressure is almost the same as that of the comparative example. Therefore, it is possible to exhibit the sealing property even in the sub-seals 14 and 24.

Further, when the reaction force is reduced (low reaction force) as described above, it is permissible to set the height dimension of the sub-seals 14 and 24 to some extent. Therefore, it is possible to avoid a situation in which the height dimension of the sub-seals 14 and 24 is insufficient and no surface pressure is generated on the lip-shaped seals 12 and 22 on the opposite side, so that the gasket as a whole can be used as a whole. It is possible to secure the sealing property.

In the embodiment, the inclined surfaces 15 and 25 and the reaction force receiving portions 16 and 26 are provided on both the sub-seal 14 of the anode side gasket 11 and the sub-seal 24 of the cathode side gasket 21, but these inclined surfaces. 15, 25 and the reaction force receiving portions 16, 26 may be provided only on any one of the sub-seals 14, 24.

The sub-seals 14 and 24 may have the following configurations.

Second embodiment ...
In the example shown in FIG. 5, in addition to the configuration according to the first embodiment, the recesses 19, in order to adjust the magnitude of the reaction force generated on a part of the inclined surfaces 15, 25 of the subseals 14, 24, 29 is provided. The recesses 19 and 29 are formed as grooves extending in the longitudinal direction of the sub-seals 14 and 24. The recesses 19 and 29 are formed in an arc shape in cross section. A plurality of recesses 19 and 29 may be provided. The concave portions 19 and 29 may be provided with a convex portion (not shown) in place of or in combination with the concave portions 19 and 29. In this case, the protrusions are formed as ridges extending in the longitudinal direction of the sub-seals 14, 24. The cross-sectional shape of the convex portion is an arc shape. A plurality of convex portions may be provided.

Third embodiment ...
In the example shown in FIG. 6, the side surfaces 17 and 27 of the sub-seals 14 and 24 opposite to the lip-shaped seals 12 and 22 become higher as they move away from the lip-shaped seals 12 and 22 in order to adjust the magnitude of the generated reaction force. It is formed as an inclined surface-like side surface that is inclined in a direction in which the dimension gradually decreases. When the side surfaces 17 and 27 of the sub-seals 14 and 24 are formed in an inclined surface shape in this way, the reaction force receiving portions 16 and 26 are less likely to fall toward the side surfaces 17 and 27.

Fourth Embodiment ...
In the example shown in FIG. 7, flat portions 20 and 30 having a flat surface are provided between the lip-shaped seals 12 and 22 and the sub-seals 14 and 24 in order to adjust the magnitude of the generated reaction force. When the total widths of the gaskets 11 and 21 are constant, the widths of the sub-seals 14 and 24 are reduced when the flat portions 20 and 30 are provided in this way, and the inclination angles of the inclined surfaces 15 and 25 are formed to be large by this amount.

Fifth embodiment ...
In the example shown in FIG. 8, the flat portion 20 having a flat surface is provided between the lip-shaped seals 12, 22 and the sub-seals 14, 24, as in the fourth embodiment, in order to adjust the magnitude of the reaction force generated. , 30 are provided. When the total widths of the gaskets 11 and 21 are constant, the widths of the sub-seals 14 and 24 are reduced when the flat portions 20 and 30 are provided, and the inclination angles of the inclined surfaces 15 and 25 are formed to be large by this amount. Further, in addition, the concave portions 19, 29 or the convex portions similar to those in the second embodiment are provided on a part of the flat surface of the flat portions 20 and 30.

In the gasket according to the second to fifth embodiments, the sub-seals 14 and 24 provided with the inclined surfaces 15 and 25 and the reaction force receiving portions 16 and 26 are provided as in the gasket according to the first embodiment. Further, since the gap spaces 18 and 28 are formed, the magnitude of the generated reaction force can be reduced, and the sealing function can be achieved even at low compression. Further, since the concave portions 19, 29, the convex portions, the inclined surface-shaped side surfaces 17, 27, the flat portions 20, 30, and the like are provided, the magnitude and distribution of the generated reaction force, the electrolyte membrane 51, or the gasket 11 for the frame body are provided. , 21 contact postures and the like can be finely adjusted.

As the material (rubber material) of the gaskets 11 and 21, silicon material, EPDM material, fluorine material and the like can be considered, but the material is not limited thereto. As the frame, it is suitable to use a frame having a Young's modulus of about 3 GPa or more and a thickness of about 250 μm (on both sides of the MEA). As the material of the frame, PEN, POM, PPS and the like are used.

11 Anode side gasket 12, 22 Lip-shaped seal 14, 24 Sub seal 15, 25 Inclined surface 16, 26 Reaction force receiving part 17, 27 Side surface 18, 28 Gap space 19, 29 Recessed part 20, 30 Flat part 21 Cathode side gasket 31, 41 Separator 51 Electrolyte membrane I cell inside O cell outside

Claims (5)

A fuel cell gasket that seals between an electrolyte membrane or a frame that holds the electrolyte membrane and a pair of separators arranged on both sides in the thickness direction thereof.
An anode-side gasket that is held by one of the separators and contacts one surface of the electrolyte membrane or frame, and a cathode-side gasket that is held by the other separator and contacts the other surface of the electrolyte membrane or frame. And with
The anode-side gasket and the cathode-side gasket are integrally provided with a lip-shaped seal and a sub-seal having a height smaller than that of the lip-shaped seal, respectively.
The lip-shaped seal of the anode-side gasket is arranged at a position where it overlaps the sub-seal of the cathode-side gasket on a plane.
The lip-shaped seal of the cathode side gasket is arranged at a position where it overlaps with the sub seal of the anode side gasket on a plane.
The sub-seal of the anode-side gasket and / or the sub-seal of the cathode-side gasket is provided on an inclined surface provided so as to incline in a direction in which the height gradually increases as the distance from the lip-shaped seal increases, and on the top of the inclined surface. A gasket for a fuel cell, which comprises a reaction force receiving portion. In the fuel cell gasket according to claim 1,
A fuel cell gasket characterized in that a concave portion or a convex portion is provided in a part of the inclined surface. In the fuel cell gasket according to claim 1,
A gasket for a fuel cell, wherein the side surface of the sub-seal opposite to the lip-shaped seal is formed in an inclined surface shape that is inclined in a direction in which the height gradually decreases as the distance from the lip-shaped seal increases. In the fuel cell gasket according to claim 1,
A fuel cell gasket characterized in that a flat portion is provided between the lip-shaped seal and the sub-seal. In the fuel cell gasket according to claim 4.
A fuel cell gasket characterized in that a concave portion or a convex portion is provided in a part of the flat portion.

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