阴极湿度与电流密度对PEMFC性能的协同影响

Synergistic effect of cathode humidity and current density on performance of PEMFC

采用数值模拟与实验测试相结合的方法,研究了不同电流密度下阴极湿度(40%、70%和100%)对PEMFC性能的影响。在低电流密度下,不同阴极进气湿度无明显差别;在中电流密度下,采用70%阴极湿度的电池性能较好;在高电流密度下,采用40%阴极湿度的电池性能最佳。通过计算流体力学(CFD)分析发现,提高阴极湿度,会增加膜含水量,提升电池性能;当膜含水量饱和时,继续增加湿度会提高扩散层液态水饱和度,降低电池性能。因此随着电流密度增大,应降低阴极进气湿度,以保证电池性能。

By combining numerical simulation and experimental measurements,the effects of cathode humidity(40%,70%and 100%)on PEMFC performance was studied at different current density.At low current densities,cathode humidity has no significant effects on PEMFC performance;at middle current densities,the PEMFC with 70%cathode humidity showed the best performance;at high current densities,the PEMFC at 40%cathode humidity performed best.By analyzing the CFD results,it is found that increasing cathode humidity would improve membrane water content and improve PEMFC performance;when the membrane water content is saturated,increasing humidity would increase liquid water saturation in GDL,which decreases PEMFC performance.As the current density increasing,it is suggested to decrease cathode humidity in order to have the best cell performance.