Experimental investigation of proton exchange membrane fuel cell with metal foam flow field 2019-01-0388
Compared to conventional flow field, metal foam is widely considered to enhance species transport in the PEMFC (proton exchange membrane fuel cell) significantly thanks to the high porosity (higher than 90%) and conductivity under high current density condition. In this study, the PEMFC with metal foam as cathode distributor is experimentally investigated carefully under normal and subzero operation conditions. And the parallel flow field is utilized for the anode. Besides, the electrochemical impedance spectroscopy (EIS) data is acquired to character the Ohmic, polarization and polarization loss. The metal foams are treated with different Polytetrafluoroethylene (PTFE) loadings (10, 20 and 40 wt%) and it is found that there exists an optimized PTFE loading for the water and thermal management in PEMFC under normal operation condition. Meanwhile, the effects of inlet gas humidity and flow rates are also studied, the results of which show that the cathode inlet gas humidity has little influence on PEMFC performance because of the high water storage of metal foam. As a comparison, it decreases obviously with the decrement of anode inlet humidity. In addition, the high flow rate can greatly increase the limiting current density of PEMFC. Under cold start operation condition, the effects of start-up temperature and current density on the cold start performance of PEMFC are also studied and the high frequency resistance (HFR) is utilized to characterize the water content and ice formation/melting in the cell. The experimental results show that high PTFE loading is helpful to PEMFC cold start performance. Overall, the results shown in this study will facilitate a further understanding of the PEMFC with metal foam flow field.
Xu Xie, Xiaoyan Sun, Mengqian Zhu, Guobin Zhang, Siyuan Wu, Kui Jiao, Jae Wan Park
Tianjin Univ., University of California - Davis