Sealing Structure Of Fuel Cell

Abstract

Disclosed is a sealing structure of a fuel cell, including a film-electrode composite (10) interposed between a first gasket (30) integrated with a separator (20A) and a second gasket (40), capable of ensuring stable sealing performance and stabilizing power generation performance in a power generation range even when an offset exists between the gaskets (30, 40) at either side of the film-electrode composite (10) due to poor assembling accuracy. To this end, the first gasket (30) has a bank-shaped main lip (32) of which top portion (32a) is brought into close contact with the film-electrode composite (10). The second gasket (40) has a flat sealing portion (42) and a sub lip (43) protruding from this flat sealing portion (42) at a position opposing the main lip (32), and the flat sealing portion and the sub lip are brought into close contact with the film-electrode composite (10). The width (w1) of the top portion (32a) of the main lip (32) is larger than the estimated maximum offset, is smaller than the width (w2) of the flat sealing portion (42), and is larger than the width (w3) of the sub lip (43).

Description

technical field [0001] The present invention relates to a sealing structure in which a membrane-electrode complex is sandwiched by gaskets integrally provided on a separator in a fuel cell, wherein the separators are disposed on both sides in the thickness direction of the membrane-electrode complex . Background technique [0002] A fuel cell has a stacked structure in which membrane-electrode assemblies (MEA) and porous gas diffusion layers (GDL) are alternately arranged on both sides of a polymer electrolyte membrane, and separators are stacked. A pair of catalyst electrode layers is set, the porous gas diffusion layer is stacked on both sides of the membrane-electrode complex in the thickness direction, the separator is made of carbon or metal, and the fuel gas and the oxidizing gas flow into the membrane-electrode complex. Both sides of the electrode complex flow through, and electricity is generated by an electrochemical reaction that is a reverse reaction of electroly...

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Problems solved by technology

[0007] However, in this case, although the surface pressure required by the sealing surface of the sealing protrusion 131 of the gasket 130 can be ensured, because the surface pressure is dispersed on the sealing surface of the flat sealing portion 141 using the gasket 140, and it is not compatible with the sealing surface. There is a problem that the required airtightness cannot be obtained because the surface pressure is lower than that on the protrusion 131 side

Therefore, in order to compensate for this decrease in hermeticity, such as Figure 10 In another prior art fuel cell sealing structure shown in a separated state, it is considered that a gasket 150 having a sealing protrusion 151 and a flat sealing portion 152 is arranged in a spiral shape on the separator 120 on both sides. In addition, the method of sandwiching the membrane-electrode assembly 110 using the sealing protrusion 151 and the flat sealing part 152 is performed at two places in the width direction, but in this case, there is a problem that the width of the gasket 150 becomes larger.

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