Topology optimization of gas channels in proton exchange membrane fuel cells

Optimizing the gas channels (GCs) plays an important role on improving the performance of proton exchange membrane fuel cells (PEMFCs). In this study, a topology optimization (TO) model is developed for optimizing the cathode GCs. A reduced two-dimensional (2D) reactive transport model is developed based on the 3D half-cell model, which considers the multiscale oxygen reactive transport processes inside GCs, the gas diffusion layer and the catalyst layer. The reduced 2D surrogate model can predict the polarization curve agreeing well with experimental results. The TO is employed to optimize the GCs with the objectives of reducing flow resistance and increasing the current density. A continuous scheme is developed to conduct the TO under high inlet velocity. GCs with five different inlet/outlet configurations are optimized. As validated by 3D simulations, the TO structures can obtain higher current density with reduced pressure drop compared with parallel GCs. Finally, the TO GCs are compared with existing bio-inspired GCs. The tree-like structure with wider inlet/outlet channels and narrower center channel is considered as a promising design for future investigation. The present study is helpful for the designing of next-generation of GCs for better cell performance.