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Abstract The flow field structure of a proton exchange membrane fuel cell (PEMFC) is a determining factor for improving the cell power density. In this study, a universal alternating flow field design for the first time is proposed, which arranges structural units with different flow resistances in an alternating way to significantly improve the gas transfer rate into the electrode, with the advantages of easy machining and low pumping loss. Based on the design, it is proposed and tested large‐scale fuel cells with three novel flow fields by combining a parallel channel, baffled channel, serpentine channel, and narrowed channel. The results show that the design can significantly enhance the gas supply efficiency and that the novel baffled flow field improves the PEMFC performance by 23% with low pumping loss. The design employed in the study offers additional options for flow field optimization and contributes to the early achievement of next‐generation ultrahigh power density fuel cells.

In this study, a 3D + 1D (three-plus-one dimensional) multiphase PEM (proton exchange membrane) fuel cell model is developed, in which the detailed channel two-phase flow is also considered based on the two-phase Darcy's law. Compared with conventional 3D fuel cell models, the 3D + 1D model improves calculation efficiency and stability. Utilizing this model, the simulation work is conducted on an automobile PEM fuel cell (309.12 cm2) with the full flow field morphology considered. Its accuracy is comprehensively validated at this scale against the experimentally measured polarization curves and HFR (high frequency resistance) under different anode and cathode stoichiometric ratios and pressures and operating temperatures, indicating the model reliability. Subsequently, we numerically investigate the influence of four flow field configurations on cell performance characteristics, including the wave-like, dotted, baffled, and straight flow fields. It is found that the dotted and baffled configuration effectively improved cell performance, but the wave-like flow field has little influence on cell performance compared with straight flow field. Moreover, it is found that decreasing the channel/rib width decreases the concentration loss, but it also increases the ionic ohmic loss, resulting in an optimal channel/rib width for cell performance improvement. [ABSTRACT FROM AUTHOR]