Fuel cell

Abstract

A first seal member is provided integrally on a surface of a first metal separator. The first seal member includes a base portion provided integrally on the first metal separator, a columnar portion protruding from the base portion, and a curved edge portion provided on the columnar portion. The curved edge portion has a predetermined radius of curvature.

Description

RELATED APPLICATIONS[0001]This application is a divisional application of U.S. application Ser. No. 10 / 745161 filed Dec. 22, 2003 which claims priority to Japanese Patent Application No. 2002-375441 filed Dec. 25, 2002. The contents of the aforementioned applications are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a fuel cell including an electrolyte electrode assembly, and metal separators for sandwiching the electrolyte electrode assembly. The electrolyte electrode assembly includes a pair of electrodes and an electrolyte interposed between the electrodes. In the fuel cell, fluid flow fields are formed on surfaces of the separators for supplying fluids such as a reactant gas and a coolant along surfaces of the separators. Each of the fluid flow fields is connected between a fluid supply passage and a fluid discharge passage.[0004]2. Description of the Related Art[0005]For example, a solid polymer...

AI Technical Summary

Benefits of technology

[0013]A main object of the present invention is to provide a fuel cell having a seal member with a simple structure in which the sealing performance between the seal member and the metal separator is reliably maintained, and the desired power generation performance can be achieved.

[0015]Since the seal member includes the base portion, the columnar portion, and the curved edge portion in contact with the sealing area under pressure, the contact area between the seal member and the sealing area is large in comparison with the conventional seal member having a lip shape. Even if the metal separators are deformed due to the gas pressure in the fuel cell, or even if surfaces of the metal separators are corrugated, warped, or distorted, the desired sealing performance can be achieved.

[0016]When a plurality of the fuel cells are stacked to form a fuel cell stack, the toughness of the seal member against the positional displacement is improved. The curved edge portion of the seal member is in contact with the sealing area under pressure. When the sealing area is displaced laterally, the columnar portion of the seal member is deformed, and thus, the curved edge portion of the sealing member moves laterally together with the sealing area. When the fuel cell is mounted in a vehicle, the seal member is kept tightly in contact with the metal separator under pressure, and the anti-vibration and the anti-shock performance can be improved.

[0017]The aspect ratio (H / W) of the seal member is 1.5 or less. Therefore, when the fuel cells are stacked to form the fuel cell stack, it is unlikely that the curved edge portion of the seal member is deformed excessively, or tilted away from the sealing area. The toughness of the seal member against the positional displacement is improved.

Problems solved by technology

If the desired sealing function of the gaskets 2 can not be performed due to the positional displacement, leakage of the reactant gas (fuel gas and / or oxygen-containing gas) and coolant may occur.

Therefore, even if the seal members and the separator body are formed into one piece, the desired sealing performance may not be achieved for the fuel cell in some automobile applications.

Specifically, positional displacement may occur at the end portions of the seal members due to vibrations during the travel of the vehicle and impacts at the time of sudden acceleration and sudden braking.

If the positional displacement occurs, it is difficult to maintain the desired sealing performance.

In the case of the fuel cell using a metal separator, surfaces of the metal separator are deformed, distorted or warped easily.

However, the end portions of the seal members can not be deformed in accordance with the deformation of the metal separator.

Thus, the sealing pressure between the surfaces of the separator and the seal member is not maintained at a sufficient level for sealing.

It is difficult to maintain the desired sealing performance.

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