Method of operating a fuel cell stack

摘要

One aspect of the invention includes the discovery that pinholes in the membrane of the membrane electrode assembly may be caused by hygroexpansive ratcheting. In one embodiment of the invention, a fuel cell stack including a plurality of cells each having a membrane electrode assembly each including a membrane manufactured by an extrusion method and operated so that the rate of drying during humidity cycling is sufficiently low to reduce or eliminate build up stresses in the membrane electrode assembly.