LAUSR

Abstract Reactant gases humidification, in most PEM fuel cell systems, is traditionally implemented to ensure both stack durability and superior performance. A cathode exhaust gases recirculation architecture allows to decrease the system volume compared to the passive humidifiers, which are classically used. Incorrect water management being responsible for irreversible degradations, a control of relative humidity at stack inlet thanks to the recirculation could be of great interest to limit their impact. In this work, investigations on performance and stability are performed during operation in recirculation mode, from the cell scale to the system scale. It was observed that high to medium recirculation ratios were able to stabilize and homogenize the cells voltages along the stack but performance was reduced due to oxygen dilution by nitrogen. Besides, large relative humidity ranges were achieved at stack inlet, which can vary from 25 to 85% and could be able to follow automotive dynamics.