Study on water transport in hydrophilic gas diffusion layers for improving the flooding performance of polymer electrolyte fuel cells

For hydrogen-based polymer electrolyte fuel cells (PEFCs), water transport control in gas diffusion layers (GDLs) by wettability distribution is useful to suppress the flooding problem. In this study, the water transport of a novel GDL with hydrophilic-hydrophobic patterns was investigated. First, we clarified that the water motion in the hydrophilic GDL with microstructures could be reproduced by the enlarged scale model. The scale model experiment also showed that the same water behavior in hydrophilic GDL can be obtained from Capillary numbers (Ca) in a range of Ca similar to 10(-5) to 10(-3). As the computational load is inversely proportional to Ca, the computational load could be reduced by 1/100th by using Ca similar to 10(-3), which is 100 times higher than PEFC operation (Ca similar to 10(-5)). Finally, the simulation with Ca similar to 10(-3) was performed, and we showed that the GDL with straight region of contact angle 50 degrees minimized the water accumulation. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.