MAINTAINING AND RESTORING PEM FUEL CELL PERFORMANCE DESPITE SUB-FREEZING BOOT STRAP AND FREEZE/THAW CYCLES

摘要

Temperature of cathodes (34, 92) of fuel cells (16, 80) are maintained at sufficient temperatures above temperatures of corresponding anodes (24, 90) either before, during or after cold starts and after freeze thaw cycles to cause migration of water from cathodes to anodes, thereby to preserve or restore performance. Temperatures may be controlled by heaters (48, 49, 54) or by heating (91, 96) process air, by flowing air through just the anode to be cooled by vaporization, by flowing air through both anodes and the cathodes, the cathode's air being warmer, or by bleeding (120) H2 into cathodes momentarily.