METHOD FOR OPERATING A FUEL CELL, POLYMER-ELECTROLYTE MEMBRANE FUEL CELL WHICH WORKS WITH THIS METHOD AND PROCESS FOR PRODUCING IT

摘要

The invention relates to a method for operating a polymer-electrolyte membra ne (PEM) fuel cell. When operating known polymer electrolyte membrane fuel cell s it has to be made sure that especially the phosphoric acid does not directly contact the metal bipolar plate of the fuel cell at high temperatures. In order to avoid such a contact, a sufficiently electroconducting intermediate layer (10, 20) is interposed between the membrane electrode unit (1) and the bipolar plate (3) of the fuel cell, which prevents phosphoric acid or a mixture of phosphoric acid and water that may escape from the membrane- electrode unit (1) from reaching the bipolar plate (3). For producing the fu el cell according to the invention an at least two-layer stratified structure (10, 20) is introduced which becomes more hydrophobic and more finely pored with increasing proximity to the bipolar plate (3).