All-scale investigation of a commercial proton exchange membrane fuel cell with partially narrow channels.

Flow field design and optimization are critical for the proton exchange membrane (PEM) fuel cells to meet the requirement of ultra-high power density commercial applications. However, the multi-physics transport mechanism inside such large-scale PEM fuel cells has not been fully understood. In this study, we have developed a three-dimensional (3D) PEM fuel cell model. It is first validated against the experimental data obtained from a small-size cell. Thereafter, based on this model, the performance characteristics of a large fuel cell (cell area: 245.76 cm2) assembled with a partially narrow flow field are elucidated, while the full bipolar plate (BP) and cell morphology are also considered. It is found that the partially narrow flow field can not only significantly increase the net power density of PEM fuel cells, but also effectively improve the uniform distribution of species with the staggered partially narrow (SPN) zone arrangement between adjacent channels. While this flow field can improve the cell performance, the blindly increasing of the narrow zone numbers may play a negative impact on the net power density due to the dramatic increase in pressure drop. Finally, the partially narrow channel can indeed provide improved drainage capacity. • Liquid water cooling is considered in the large-scale 3D model of PEM fuel cell. • Comprehensive comparison between the partially narrow and parallel flow fields. • The partially narrow channel has the advantage of enhancing oxygen convection. • The drainage mechanism of the partially narrow channel is clearly presented. [ABSTRACT FROM AUTHOR]