An Innovative Three Dimensional Numerical Model for Bipolar Plates to Enhance the Efficiency of PEM Fuel Cells

Abstract

The efficiency of proton exchange membrane (PEM) fuel cell is straightly correlated to the bipolar plate design and fluid channel arrangements. Higher produced energy can be attained by optimal design of type, size, or patterns of the channels. Previous researches showed that the bipolar plate channel design has a considerable effect on reactant distribution uniformity as well as humidity control in PEM fuel cells. This paper concentrates on enhancements in the fuel cell performance by optimization of bipolar plate design and channels configurations. A numerical model of flow distribution based on Navier-Stokes equations using individual computer code is presented. The results gained from this three dimensional, multi-component simulation showed excellent agreement with the existed experimental data in the previous publications. In this paper, a new flow field design inspired from the nature is presented and analyzed. In this work, two mostly used flow channels design — serpentine and parallel — have been studied and compared to the newly introduced bio inspired bipolar plate design. To compare, velocity distributions of fluid, mass fraction of reactant gases and polarization curves for different bipolar plate designs have been analyzed. The key design criteria in this study are based on more homogenous molar spreading of species and more uniform velocity distribution along the flow channels and also higher voltage and power density output in different current densities. By developing a numerical code it was concluded that the bio inspired bipolar plate can enhance the PEM fuel cell performance especially at middle current densities, where the losses caused by mass transport limitations are not significant.