US Patent 7232582 Fuel cell

First and second separators include first and second metal plates. The first metal plate has first embossed protrusions protruding toward a membrane electrode assembly to form an oxygen-containing gas flow passage. The second metal plate has second embossed protrusions protruding toward another membrane electrode assembly to form a fuel gas flow passage. Further, the second metal plate has third small embossed protrusions protruding toward the first metal plate.