A factorial study to investigate the purging effect on the performance of a dead-end anode PEM fuel cell stack

This paper presents an experimental investigation of the effect of hydrogen purging time period and duration on the performance of a proton exchange membrane (PEM) fuel cell stack with a dead-end anode. The objective is to develop a better understanding of the interactions between the purging parameters and the cathode air-stoichiometry. It employs a full factorial approach for three factors (purging period, purging duration and air-stoichiometry) with two levels and three replications. The study is performed on a 300 cm², 24-cell PEM fuel cell stack with the rated power of 1.5 kW. The stack was operated with water cooling, fully humidified air and dry hydrogen at the ambient pressure. The results showed that the stack performance is significantly influenced by the interactions of the purging parameters and the cathode air-stoichiometry. The least square model was utilized to determine the optimum values of these parameters with regard to the stack performance and hydrogen utilization. For the present stack, the optimum values of parameters were: purging period of 3 min, purging duration of 4 s and the cathode air-stoichiometry of 200%.