Experimental study of voltage uniformity and stability of H2/O2 PEM fuel cell stack with dead-end anode and recirculation cathode

Abstract

Dead-end anode and recirculation cathode is an operating mode effectively improving the gas reactant utilization of hydrogen–oxygen proton exchange membrane fuel cell (H₂/O₂ PEMFC) stack. However, the difference of single cells in the stack, will be further expanded due to the flooding and impurities and necessary purge for removing them. In this work, the voltage uniformity and stability of H₂/O₂ PEMFC under different operating conditions are investigated based on a dead-end anode and recirculation cathode PEMFC stack. Research indicates that enhancing the current density and temperature, lowering the inlet gas pressure will diminish the uniformity in stack voltage. The analysis of the experimental pattern reveals a positive correlation between the voltage uniformity and stability. This is due to the water flooding or membrane dehydration phenomenon of the single-cell leading to a reduction of the single-cell voltage and the voltage uniformity of the stack, while the water flooding or membrane drying phenomenon makes the stack more unstable and the purge interval shorter. Based on these experimental results, the best operating scheme for the designed stack is proposed, which is of some guidance and reference value for the practical application of air-cooled PEMFC in the hundred-watt class.