Patent ID: 8263289
Filing Date: 2012-09-11
Classification: B23K,H01M,Y02E,Y02P,Y02T

Abstract:
1. A fuel cell stack comprising: a membrane electrode assembly including electrode catalyst layers and an electrolyte membrane between the electrode catalyst layers; a metal separator on each side of first and second surfaces of the membrane electrode assembly, each metal separator having a base material comprising a stainless steel containing at least one of Fe, Ni, and Cr as a main component and having a corrosion-resistant coating layer provided only on a reaction-side surface facing the membrane electrode assembly, each metal separator constituting gas flow paths, the membrane electrode assembly and the metal separators constituting a cell of a fuel cell; and a temperature-control medium flow path provided by forming joined portions where back surfaces of the metal separators of adjacent stacked cells are in contact with each other; wherein the joined portions are formed by welding portions of the metal separators that constitute groove bottoms of the gas flow paths; and wherein an oxide film is provided on a surface of respective welded portions after welding by at least one of: