基于新型波浪形流道的大规模质子交换膜燃料电池堆功率性能提升研究

Abstract Optimization of the flow channel structure is crucial for thermal and energy management in the improvement of power performance in a proton exchange membrane fuel cell (PEMFC). In this study, the power performance improvement of a large-scale PEMFC stack with the designed novel wavy flow channels in bipolar plates was analysed. This novel wavy flow channels were featured by the spatial overlapped hydrogen and air wavy channels, and asymmetric geometries of gas and coolant channels in bipolar plates. The power density of this large-scale PEMFC stack with wavy flow channels was assessed through experiments. A three-dimensional coupled numerical simulation model was built to investigate characteristics of flow dynamics, heat and mass transfer and electric energy. Detailed distribution characteristics of the gas flow velocities and molar concentrations, water in different phases, temperature and proton conductivity, electric energy at corresponding interfaces under different coolant temperatures (from 60 °C to 80 °C) were comparatively discussed. The intermittent velocity mode of the air flow was produced in the wavy flow channel, which served as the mechanism of enhancing the gas transfer during electrochemical reaction and thereby improving power density of the PEMFC stack. The proton conductivity at the proton exchange membrane was shown sensitive to a high coolant temperature. The effect of heat transfer by the coolant channels between the hydrogen and air flow channels were revealed. The ohmic heat source, reaction heat source and various types of entropy generations were derived for analysis. Results showed that the PEMFC stack with novel wavy flow channels and a higher coolant temperature of 80 °C could effectively decrease the ohmic heat source, reaction heat source and various types of entropy generations.