Current density and temperature distribution measurement and homogeneity analysis for a large-area proton exchange membrane fuel cell

Abstract

Homogeneous distribution of electro-chemical reaction rates among the activation surface is critical for improving the performance and durability of automotive proton exchange membrane fuel cells (PEMFCs). Segmented measurement technology is commonly used to characterize the local physical-parameter distribution in the PEMFC. In this study, the local current density (LCD) and temperature distributions of a PEMFC with the activation area of 108 cm2 and various cathode flow fields are experimentally investigated. A homogeneity parameter is introduced to evaluate the homogeneity of LCD distribution. The results show that the performance and LCD distribution uniformity of the cell with dot-parallel flow field are much better than that with parallel and parallel-serpentine flow fields. The temperature distribution is generally positively correlated with LCD distribution. For the LCD distribution, the high LCD region firstly appears in the cathode downstream region, and gradually transfers upstream with increasing the current load. With the increase of inlet humidity, the LCD near the cathode inlet is improved due to the improvement of membrane hydration. Increasing the cathode stoichiometry can effectively improve the uniformity of LCD distribution, and mitigate the local oxygen starvation, especially at high loads.