Polymer electrolyte membrane fuel cell performance degradation by coolant leakage and recovery

Abstract

Coolant leakage leads to decrease in performance during the operation of electric vehicles which make use of polymer electrolyte membrane fuel cells (PEMFC). This study examines the effects of various coolant leak conditions in 3-cell stack and single cell. The experimental results show that an irreversible reduction in performance occurs after coolant injection into the anode side of the stack. Poisoning of carbon monoxide (CO) on the platinum (Pt) catalyst is caused by electro-oxidation reaction of EG. Water cleaning is selected because CO poisoning is desorbed to reaction with water molecules. Performance is quickly reduced when the interval between coolant injections is short. Performance reduction is indicated by the experimental results for the gas diffusion layer (GDL) and the membrane electrode assembly (MEA). It shows that performance of the MEA with the GDL exposed to coolant decreased, but it is recovered after water cleaning. In contrast, results for performance of the MEA exposed to coolant for long time could not be reversed after water cleaning. Therefore, we propose that performance degradation of coolant leak on the Pt catalyst surface and GDL can be recovered by the water cleaning simply without disassembly of stack.