Fuel cell

Abstract

The present invention provides a fuel cell having a layered structure, including: a membrane electrode assembly having a fuel electrode, an oxidation electrode, and an electrolyte membrane held between the fuel electrode and the oxidation electrode; and stainless steel separators holding the membrane electrode assembly therebetween. The stainless steel separator contains Cr and Fe; the Cr concentration by mass % by mass ratio of Cr to Fe at the separator surface facing the fuel electrode is from 0.7 to 1.3; and the Cr concentration by mass % by mass ratio of Cr to Fe at the separator surface facing the oxidation electrode is less than 0.7.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a fuel cell, and in particular relates to a solid polymer electrolyte fuel cell. [0003] 2. Description of the Related Art [0004] In a fuel cell in which a polymer electrolyte is used, electric power and heat are simultaneously generated by an electrochemical reaction of a fuel gas containing hydrogen gas and an oxidizing gas containing oxygen gas or air. The fuel cell basically has a polymer electrolyte membrane for selectively transporting hydrogen ions, and a pair of electrodes, that is, an anode electrode and a cathode electrode formed on both surfaces of the polymer electrolyte membrane. The electrode generally consists of a catalytic layer formed on a surface of the polymer electrolyte membrane layer and a gas-diffusion layer formed on an outside surface of the catalyst layer. The catalyst layer is mainly composed of a carbon powder supporting a platinum group metal catalyst. Th...

AI Technical Summary

Benefits of technology

[0015] The present invention was made in consideration of the above problems, and an object of the present invention is to provide a fuel cell which can prevent a decrease in durability due to corrosion of a separator in a use environment and a decrease in output performance due to excessive increase in contact resistance of a separator with a MEA.

[0016] An object of the present invention according to another aspect of the invention is to provide a fuel cell which can improve efficiency thereof by inhibiting an increase in electrical resistance in a fuel cell layering direction as long as possible, and which can inhibit corrosion of a separator material on a surface of a cooling medium and a contamination of the cooling medium due to a leak of impurity metal ions, and can improve durability of a cooling medium surface.

[0017] An object of the present invention according to another aspect of the invention is to provide a technique which can prevent a contamination of a cooling medium due to corrosion of a fuel cell and formation of a short circuit due to the contamination without decrease in cooling effect and increase in cost.

Problems solved by technology

That is, when impurity ion metal ions are released from a separator surface contacting an acid solution, the electrolyte catalyst and the ion-exchange membrane are contaminated, so that durability is decreased due to increase in collecting resistance.

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