Characteristics of proton exchange membrane fuel cell considering “dot matrix” gas distribution zones and waveform staggered flow field with cooling channels

Abstract

Conventional three-dimensional (3D) computational fluid dynamics (CFD) simulations of proton exchange membrane fuel cell (PEMFC) are limited to the single-channel scale, while the influence of gas distribution zone and complex flow structure with multiple channels is ignored and the role of cooling flow field is not considered. Therefore, a metal bipolar plate structure with “dot matrix” gas distribution zones and a waveform staggered flow field with small cathode size flow channels is proposed. The cooling flow fields are set up to analyze the effect on the output performance of the PEMFC. Firstly, the analysis of the gas and liquid distribution within the flow field reveals a maximum error of 10.36% for the cathode gas concentration, which is much larger than the anode (4.51%). The large pressure drop at the cathode leads to a small value for the liquid saturation. Secondly, the output parameters of the PEMFC are compared at different operating pressures, which results in a high operating pressure that clearly contributes to the improved performance of the fuel cell. Furthermore, when the reaction gas is counter-flow, the electrochemical reaction rate is faster and the water hydration level of the proton exchange membrane (PEM) is higher. The cooling flow field is most effective when it flows in the same direction as the oxygen flow. Finally, the effects of different thermal boundary conditions on the distribution of oxygen within the cathode flow field are compared and the results show that high local temperatures are also a major factor in the uneven distribution of oxygen concentration in the flow field.