JP2013131491A - Gasket for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the inflow of a reductant gas and an oxidant gas to a non power generation region, the deterioration of the generation efficiency due to a gasket protruding to a passage region, and the deterioration of the cooling efficiency due to the gasket protruding to the passage region in a manifold hole of a refrigerant liquid.SOLUTION: A gasket 1 is disposed between lamination components of a fuel battery cell and includes a flat sheet like base part 11 which is formed by a material having rubber-like elasticity, extends so as to enclose a passage region of the fuel battery cell, and has an inner edge part 11a reaching an edge part 20a of the passage region. Fine protruding sections 13, extending along the inner edge part 11a, are provided around the periphery of the inner edge part 11a in the sheet like base part 11. Each fine protruding section 13 is formed in a size, which does not allow the inner edge part 11a of the sheet like base part 11 to expand and deform, even when completely crushed.

Description

  The present invention relates to a gasket used for a fuel cell constituting a power generation element of a fuel cell.

  Fuel cells that operate at relatively low temperatures, such as polymer electrolyte fuel cells (PEFC), can be used in a variety of fields, including automobiles, households, portable power supplies, and portable terminal power supplies. It is expected and already commercialized in some areas. The basic structure of this type of fuel cell is that MEA (Membrane Electrode Assembly) with a negative electrode layer (anode) and a positive electrode layer (cathode) on both sides of an electrolyte membrane (ion exchange membrane) is made of carbon. These are sandwiched between separators made of synthetic resin or metal to form a single power generation unit (fuel cell), and these are stacked and connected in series to form a fuel cell stack so that a high voltage can be obtained.

In this type of fuel cell, as shown in FIG. 7, a reducing agent (fuel gas such as hydrogen H ₂ or methanol containing hydrogen H ₂ ) is supplied to the anode 101 in the MEA 100 through one flow path 111 to be oxidized. An agent (air containing oxygen O ₂ ) is supplied to the cathode 102 in the MEA 100 through the other channel 112, and is an electrochemical reaction that is a reverse reaction of water electrolysis, that is, hydrogen H ₂ and oxygen O ₂ to water H ₂ O. Electric power is generated by the reaction of generating.

Specifically, hydrogen H ₂ supplied to the anode 101 in the MEA 100 is decomposed into electrons e ⁻ and hydrogen ions H ⁺ by the catalytic action of the anode 101. Then, the electrons e ⁻ generated thereby flow as an electric current through the external load R toward the cathode 102 in the MEA 100. Further, since the hydrogen ions H ⁺ generated by separating the electrons e ⁻ from the hydrogen H ₂ are attracted to the electrons e ⁻ of the cathode 102, they move to the cathode 102 through the electrolyte membrane 103 in the MEA 100.

On the other hand, oxygen O ₂ in the air supplied to the cathode 102 in the MEA 100 receives electrons e ⁻ by the catalytic action of the cathode 102 and becomes oxygen ions O ⁻ . The oxygen ions O ⁻ are combined with hydrogen ions H ⁺ that have moved from the anode 101 through the electrolyte membrane 103, thereby generating water H ₂ O.

That is, in this type of fuel cell, hydrogen H ₂ necessary for power generation, or a reducing agent gas composed of methanol containing hydrogen H ₂ or an oxidant gas composed of air containing oxygen O ₂ is supplied to both electrodes to generate power. Then, the resulting water H ₂ O is discharged, and when cooling is required, water or antifreeze liquid is also circulated as a refrigerant. In order to supply these types of fluids to the fuel cell, the flow paths of these fluids must be ensured so that these fluids do not dissipate from the space to be supplied or other fluids do not flow in. For this reason, each fuel battery cell incorporates a rubber-like elastic material, especially a gasket molded from a material with good moldability, such as a rubber elastic body, thermoplastic elastomer, or thermosetting resin. It is.

  In order to increase the power generation efficiency, it is important that the reducing agent and the oxidizing agent do not flow into the non-power generation region. For example, the periphery of a hole (called a manifold hole) that penetrates in the stacking direction of fuel cells and supplies fluid to each fuel cell or discharges fluid from each fuel cell is also a non-power generation region. In order to prevent a decrease in power generation efficiency due to the inflow of fluid into the non-power generation region, it is effective to use a sheet-like gasket as a gasket incorporated in each fuel cell.

  FIG. 8 is a partial plan view showing an example of a conventional gasket, FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8, and FIG. 10 shows a state in which the conventional gasket is compressed by lamination in the same position as FIG. It is sectional drawing cut | disconnected by.

  That is, the gasket 200 is formed integrally with a rubber elastic body or the like on one side of the separator 300, and has a flat sheet-like base 201 and a seal protruding from the outer periphery of the sheet-like base 201 with a cross-sectional chevron. It consists of a lip 202. The sheet-like base 201 is developed so as to cover the periphery of the opening 301 as a manifold hole established in the separator 300 and the periphery of the formation region of the channel groove 302 extending from the opening 301. 201 a is flush with the edge of the formation region of the flow channel 302.

  As shown in FIG. 10, the gasket 200 having the above configuration is assembled in a fuel cell and compressed in such a way that the seal lip 202 is completely crushed by stacking, and the sheet-like base 201 is stacked with, for example, MEA or the other separator. By interposing between the component 400 and the periphery of the opening 301 and the periphery of the region where the flow channel groove 302 is formed, inflow of the reducing agent gas and the oxidizing gas into the gap is prevented. . In addition, as a prior art of a sheet-like gasket, there exists a thing like the following patent document 1, for example.

JP 2004-342516 A

  However, according to the conventional gasket 200, when the sheet-like base 201 is overcompressed, the edge 201a of the sheet-like base 201 is deformed so as to bulge as shown in FIG. It protrudes to the formation region (or the opening 301 shown in FIG. 8), and the flow passage area is reduced by that amount, so that a predetermined gas flow rate and refrigerant liquid flow rate cannot be secured, resulting in power generation efficiency and cooling. There was a risk that efficiency would decrease.

  On the other hand, if the tightening force due to the lamination is reduced so as not to be in such an overcompressed state, the base 201 and the laminated component 400 are formed around the opening 301 and the area of the flow channel 302 that are non-power generation areas. There was a gap between them, and the reducing agent gas or oxidant gas flowed in there, and the power generation efficiency might be reduced.

  The present invention has been made in view of the above points, and the technical problem is that the reducing agent gas and the oxidizing gas flow into the non-power generation region and the gasket protrudes into the flow channel region. It is to effectively prevent a decrease in power generation efficiency and a decrease in cooling efficiency due to the gasket protruding into the flow path region in the manifold hole of the refrigerant liquid.

  As a means for effectively solving the above technical problem, a gasket for a fuel cell according to the present invention is a gasket interposed between laminated parts of a fuel cell, and is made of a material having rubber-like elasticity. A flat sheet-like base extending so as to surround the flow channel region of the fuel cell and reaching an edge of the flow channel region is formed on the sheet-shaped base along the inner edge. An extending micro-projection is provided around the micro-projection, and the micro-projection is formed in a size that does not bulge and deform the inner edge portion of the sheet-like base portion even when it is completely crushed. The flow channel region here is a general term for a manifold hole and a region for forming a flow channel extending from the manifold hole.

  The fuel cell gasket having the above-described configuration is configured to seal a fluid such as a reducing agent, an oxidant, and a refrigerant liquid that circulates in the flow path of the fuel cell by being incorporated between the stacked components of the fuel cell. By being in close contact with the laminated part in a compressed state so that the micro-ridges along the edge of the road region are crushed, the sealing surface pressure locally increases, and the fluid flows into the gap around the channel region. Is prevented from flowing in. And even if this minute protrusion is completely crushed, the inner edge of the sheet-like base portion of the gasket does not bulge and deform toward the flow channel region, and therefore the flow channel area does not decrease.

  According to the fuel cell gasket of the present invention, it is possible to prevent a fluid such as a reducing agent or an oxidant from flowing into the gap in the non-power generation region by the minute protrusions, and to bulge the inner edge of the sheet-like base due to compression. Since the reduction of the flow path area due to the deformation can be prevented, it is possible to effectively prevent the power generation efficiency from being lowered.

1 is a partial plan view showing a first preferred embodiment of a gasket for a fuel cell according to the present invention. It is sectional drawing cut | disconnected by the II-II line | wire in FIG. It is sectional drawing which cut | disconnected the state which compressed the gasket for fuel cells of 1st embodiment by lamination | stacking in the same position as FIG. It is a partial top view which shows preferable 2nd embodiment of the gasket for fuel cells which concerns on this invention. It is sectional drawing cut | disconnected by the VV line | wire in FIG. It is sectional drawing which cut | disconnected the state which compressed the gasket for fuel cells of 2nd embodiment by lamination | stacking in the same position as FIG. It is explanatory drawing which shows roughly the mechanism of the electric power generation in a fuel cell. It is a partial top view which shows an example of the conventional gasket. It is sectional drawing cut | disconnected by the IX-IX line in FIG. It is sectional drawing which cut | disconnected the state which compressed the conventional gasket by lamination | stacking in the same position as FIG.

  Hereinafter, preferred embodiments of a gasket for a fuel cell according to the present invention will be described in detail with reference to the drawings.

  1 to 3 show a first embodiment of a fuel cell gasket according to the present invention, in which FIG. 1 is a partial plan view of the fuel cell gasket, and FIG. FIG. 3 is a cross-sectional view taken along the line II-II, and FIG. 3 is a cross-sectional view taken at the same position as FIG.

  1 and 2, reference numeral 2 is a separator which is a laminated part constituting a fuel cell, and has a plate shape or a sheet shape made of carbon, synthetic resin or metal, and has a plurality of openings serving as manifold holes. (Only one location is shown in FIG. 1) 21 is opened, and a number of flow channel grooves 22 extending from the respective openings 21 are formed on the surface in a range corresponding to the power generation region.

  The gasket 1 of the first embodiment is formed integrally with a material having rubber-like elasticity (a rubber elastic body or a synthetic resin material having rubber-like elasticity) on one side of a separator 2 and is flat. A sheet-like base portion 11 and a seal lip 12 protruding from the outer peripheral portion of the sheet-like base portion 11 with a mountain-shaped cross section are provided.

  The sheet-like base 11 is developed so as to cover the periphery of the opening 21 of the separator 2 and the periphery of the formation region 20 of the flow channel groove 22, and the inner edge 11 a of the sheet-like base 11 is an opening of the opening 21. The edge 20a reaches the edge 20a of the edge 21a and the flow channel 22 forming region 20, and is flush with the edges 21a and 20a.

  The sheet-like base portion 11 is provided with a minute protrusion 13 extending along the inner edge portion 11a. The minute protrusion 13 has a sufficiently small cross-sectional area as compared with the seal lip 12 and is formed in a size that does not cause the inner edge portion 11a of the sheet-like base portion 11 to bulge and deform even when completely compressed. Further, the inner peripheral surface of the minute protrusion 13 is substantially flush with the inner edge 11 a of the sheet-like base 11, that is, substantially the same as the opening edge 21 a of the opening 21 and the edge 20 a of the formation region 20 of the flow channel 22. It is the same.

  The fuel cell gasket 1 according to the first embodiment having the above-described configuration is incorporated in a fuel cell together with a separator 2 integrated therewith, and one side of the other laminated component in the fuel cell, for example, the separator 2 It is in close contact with the other separator 3 or the laminated part 3 such as the MEA, and seals a fluid such as a reducing agent gas, an oxidizing agent gas, or a refrigerant liquid flowing through the opening 21 and the channel groove 22.

  In this example, the height h from the joining surface of the separator 2 and the sheet-like base 11 shown in FIG. 2 to the top of the minute protrusion 13 is the sheet-like shape of the conventional gasket 200 shown in FIG. It corresponds to the thickness t of the base 201. Therefore, in the assembled state shown in FIG. 3, when the stacking interval between the separator 2 and the laminated component 3 is equal to the stacking interval between the separator 300 and the laminated component 400 in FIG. Only the lip 12 and the minute protrusion 13 are brought into close contact with the laminated component 3 in a state of being almost completely crushed, and the sheet-like base portion 11 can be brought into a state of being hardly compressed.

  The minute protrusions 13 extending along the opening edge 21a of the opening 21 and the edge 20a of the formation region 20 of the flow channel 22 are easily crushed even if the fastening force in the stacking direction is small. Since the sealing surface pressure is locally generated by the compression of the strip 13, the sheet-like base 11 and the laminated component 3 that are unfolded so as to cover a non-power generation region such as the periphery of the opening 21 and the periphery of the formation region 20 of the flow path groove 22 are provided. Therefore, it is possible to effectively prevent a reducing agent gas, an oxidant gas, or the like from flowing in between them, and to prevent a decrease in power generation efficiency.

  Further, even if the minute ridge 13 of the gasket 1 is compressed into a completely crushed state, the minute ridge 13 is sufficiently small so that the stress due to the compression is absorbed by the sheet-like base 11, and the sheet-like base Since 11 is hardly compressed, the inner edge 11 a of the sheet-like base 11 does not bulge from the opening edge 21 a of the opening 21 and the edge 20 a of the formation region 20 of the flow channel 22. For this reason, the flow channel area in the opening 21 and the flow channel area in the flow channel 22 do not decrease. Therefore, the flow rate of a reducing agent gas or an oxidant gas for obtaining a predetermined electromotive force, a refrigerant liquid for cooling, or the like. Can be secured.

  Next, FIG. 4 is a partial plan view showing a second preferred embodiment of the fuel cell gasket according to the present invention, FIG. 5 is a sectional view taken along line VV in FIG. 4, and FIG. It is sectional drawing which cut | disconnected the state which compressed the gasket for fuel cells of 2nd Embodiment by lamination | stacking in the same position as FIG.

  In the gasket 1 of the second embodiment, the difference from the first embodiment is formed by rubber only, and the seal lip 12 and the minute protrusions 13 are formed on both surfaces of the sheet-like base 11. In the point. The sheet-like base 11 is formed thicker than the first embodiment from the viewpoint of handleability.

  The fuel cell gasket 1 according to this embodiment is also assembled between the laminated parts 4 and 5 such as the separator and MEA in the fuel cell, and is in close contact with the laminated parts 4 and 5 to form a manifold hole. Sealing fluid such as a reducing agent gas, an oxidant gas, or a refrigerant liquid that flows through the openings 41 and 51 of the laminated parts 4 and 5 and a channel groove (not shown). Only the sheet-shaped base 11 can be brought into a state of being hardly compressed by being in close contact with the laminated parts 4 and 5 in a state of being almost completely crushed.

  Therefore, the same effect as that of the first embodiment can be realized.

DESCRIPTION OF SYMBOLS 1 Gasket 11 Sheet-like base 11a Inner edge 12 Seal lip 13 Minute protrusion 2 Separator (laminated part)
20 Channel groove formation region (channel region)
20a Edge 21 Opening (flow channel region)
21a Opening edge 3-5 Laminated parts

Claims (1)

  A gasket interposed between laminated parts of a fuel cell, made of a material having rubber-like elasticity, extending so as to surround the flow channel region of the fuel cell, and an inner edge portion being an edge of the flow channel region A flat sheet-like base that reaches the portion, and a micro-projection extending around the inner edge is provided around the sheet-like base, and the micro-projection is not completely crushed, but the sheet-like base A fuel cell gasket, wherein the inner edge of the fuel cell is sized so as not to bulge and deform.

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