Effect of gradient anode flow field designs on polymer electrolyte membrane fuel cells

Abstract

This study investigates non-uniform anode flow fields in polymer electrolyte membrane fuel cells, exploring ascending and descending gradient configurations in channels and metal foams. Implementing ascending gradient enhances maximum power density by up to 3.8% for channels and 5.7% for metal foams compared to descending gradients, reducing voltage fluctuations. Further analysis of gradient metal foams using water-cooling cells reveals that both designs achieve a peak power density of 1.13 W/cm2 at RH100%, with a marginal 0.2% difference. As RH decreases to 60% and 30%, performance disparities of 4.3% and 5.7% are observed, favoring ascending design. HFR values of 3.27 mΩ for ascending and 3.78 mΩ for descending metal foams at RH30% indicate superior membrane hydration properties of the ascending design, but accelerated stress tests evidence its susceptibility to degradation. This study highlights the potential for optimizing fuel cell design by manipulating anode flow field gradients, offering insight for enhancing performance.