Experimental study on self-humidified operation in PEM fuel cells

Self-humidified operation of a Polymer Electrolyte Membrane (PEM) fuel cell with dry feed conditions is experimentally investigated. Hydration of the membrane is effectively attained by employing a flow distributor configuration which aids in retaining product water. Dry air and hydrogen are used as reactants and the effects of reactant flow rate and operating temperature on performance of the fuel cell is measured. The experiments show that there is an optimum operating temperature at which the performance is high. A reduction in operating temperature resulted in decrease in performance due to condensation of product water. An increase in operating temperature also resulted in performance loss due to evaporation of product water and ensuing dehydration of membrane. It is also found that, there is an optimum flow rate of air at which the performance is high. A lower air flow rate resulted in performance loss due to oxygen starvation whereas a higher air flow rate leads to performance loss due to excess water removal and dehydration of membrane. For hydrogen, there is no optimum flow rate but the minimum flow rate is found to give higher performance as it reduces the water removal through anode side as well as the fuel wastage.