Analyzing local degradation in an industrial PEMFC under EPA US06 drive cycle via 3D-CFD

Abstract

Considerable research efforts have been made to investigate the degradation mechanisms of various components of proton exchange membrane fuel cells (PEMFCs). However, understanding the degradation of large active area PEMFCs under automotive operating conditions remains an important research focus. In this study, an unsteady 3D computational fluid dynamics (CFD) model in combination with 1D models for carbon corrosion, platinum dissolution and hydrogen peroxide production provides detailed insights into the degradation potential of a PEMFC. Typical degradation phenomena in PEMFCs are influenced by local factors such as potential, temperature and humidity. These internal states cannot be easily captured with conventional measurement methods. The simulation of a driving cycle with high dynamic load at two humidification states of the intake air showed significant local variations. Although the hydrogen peroxide concentration in the anode catalyst layer decreases at high humidity by 25%, the Pt/C catalyst decomposition in the cathode catalyst layer increases. Low humidity conditions lead to strong temporal fluctuations of the water content in the membrane, which increases the risk of mechanical fatigue. Despite the increased Pt/C decomposition observed at high humidity, improved homogeneity of the local potentials within the catalyst layers and the water content of the membrane mitigates ionomer degradation.