Patent ID: 9012109
Filing Date: 2015-04-21
Classification: H01M,Y02E

Abstract:
1. A method of pre-treating a membrane electrode assembly to shrink the membrane electrode assembly prior to assembly of the membrane electrode assembly into a fuel cell stack to reduce irreversible planar dimensional changes of the membrane electrode assembly in the fuel cell stack, comprising: a) providing a hydration process, and a membrane electrode assembly comprising a polymer electrolyte membrane constructed and arranged to selectively transport hydrogen ions and prevent H b) subjecting the membrane electrode assembly, wherein the membrane of the assembly is susceptible to irreversible planar dimensional changes upon a hydration/dehydration cycle, to the hydration process in order to provide moisture thereto and in order to expand the membrane electrode assembly; c) dehydrating the membrane electrode assembly to remove moisture therefrom and to contract the membrane electrode assembly in at least the length and width directions; and d) repeating b and c over at least one additional hydration/dehydration cycle so that the length and width to which the membrane contracts during subsequent hydration/dehydration cycles is such that that pinhole formation in the membrane is reduced when the pre-treated membrane electrode assembly is used in a fuel cell stack and so that the pre-treated membrane undergoes reversible dimensional changes upon subsequent hydration/dehydration cycles.