Effect of operating parameters on the transient performance of a polymer electrolyte membrane fuel cell stack with a dead-end anode

The operation of polymer electrolyte membrane fuel cell (PEMFC) stack with a dead-end anode requires careful consideration on the gas and water management. Water accumulation at the anode and the nitrogen crossover from cathode to anode lead to performance deterioration over time. The accumulated water and nitrogen need to be removed properly by purging method to ensure good and stable stack performance. Thus, the careful selection of the operating parameters - inlet humidification, stoichiometry, and operating current - is the key factor for ensuring efficient water and gas management. This study aims at the experimental and numerical evaluation of the effect of the key operating parameters on the transient performance of a dead-end anode fuel cell stack. The experiments were carried out on a stack with 24 cells and a catalyst active area of 300 cm(2). By employing a validated transient two-phase mathematical model of a PEMFC with a dead-end anode, numerical simulations were performed which yield a better and deeper understanding of local distribution of water and species, i.e., hydrogen, oxygen, water vapor and nitrogen. The results suggest that the performance deterioration over time is closely related to the choice of the operating conditions. The study reveals that the anode and cathode inlet conditions become a limiting factor for the stack performance. Liquid accumulation at the anode is found to be strongly related to the inlet humidification as well as water transport across the membrane, whereas the cathode stoichiometry affects the nitrogen crossover. (C) 2013 Elsevier Ltd. All rights reserved.