Durability of PEMFC under Low-humidity and Load Cycle Conditions

Abstract

Proton exchange membrane fuel cells (PEMFC) are one of the most promising technologies for use as power sources for fuel cell vehicles and residential power applications. However, it is recognized that durability is critical issues for commercialization. Generally, PEMFC for automobile use are exposed to low relative humidity and load cycle condition that cause significant degradation of membrane and catalyst. The focus of this research is to investigate the influence of the load cycle pattern on the cell degradation. Single cell tests were performed for several load cycles and the degradation of the cell performances were evaluated by monitoring of the cell voltage, internal resistance, gas crossover rate and ionic content in effluent. Also, in order to investigate the gas diffusion layer (GDL) and the membrane/ionomer degradation, contact angle measurement were made for the GDL and solid ¹⁹F-NMR measurement were conducted as the post analyses. In the load cycle conditions, the activation and diffusion polarization are remarkably increased during the test, and inadequate water content accelerates membrane/ionomer chemical degradation.