Numerical and experimental study on mass transfer and performance of proton exchange membrane fuel cell with a gradient 3D flow field

Abstract

The design of the fuel cell cathode flow field affects its internal heat and mass transfer, thus influencing the fuel cell performance. Building on previous research on 3D flow fields, this study analyzes the impact of the ratio of the main and sub channels width, the ratio of the main/sub channel length to the transition region width on mass transfer and performance. The study proposes a 3D flow field design with a gradual variation in the length of main/sub channels. Numerical and experimental analysis was carried out and results indicate that reducing the D/d ratio can better alleviate ohmic losses at medium and low current densities, while reducing the L/W ratio can better alleviate concentration losses at high current densities. Compared to traditional parallel straight flow field PEMFC, the power density of the gradient 3D flow field PEMFC could increase by 21.54% at 1.9 A·cm−2. The experimental result of the PEMFC is basically consistent with the numerical simulation.