Geometry optimization and performance analysis of a new tapered slope cathode flow field for PEMFC

In proton exchange membrane fuel cell (PEMFC), the cathode flow field structure affects the performance of PEMFC. In a previous study, we proposed a new tapered slope flow field (TSFF). In this study, Ansys Fluent software was used to simulate a PEMFC with a tapered slope cathode flow field structure. The results show that the performance of the TSFF is superior, the drainage efficiency is higher, and the oxygen mass fraction distribution is more uniform. Furthermore, comparing double-sided TSFF with different lengths, the PEMFC performance first increases and then decreases as the length of the tapered slope increases. In particular, the oxygen mass fraction and current density distributions are more uniform in the double-sided TSFF with L = 1.2 mm and the PEMFC performance is the best, and compared with the serpentine flow field, the maximum power density of PEMFC is increased by 5.89%. A detailed analysis of the geometric structure of the flow field can help us understand the reasons why the TSFF structure improves the performance of PEMFC and comprehensively evaluate the flow field performance. The TSFF enhances the flow rate of reactant diffusion to the CL and enhances the mass transfer downstream of the flow field. In particular, when L = 1.2 mm, the relative magnitude of the reactant flow resistance loss in the double-sided TSFF was 1.86% smaller than that of the serpentine flow field.