挡板分布对PEMFC传质特性的影响

Effect of baffle distribution on mass transfer characteristics of PEMFC

合理的双极板流道结构设计对提高质子交换膜燃料电池(PEMFC)性能具有重要意义。建立单直流道PEMFC的三维模型,并在流道出口处添加矩形挡板,研究挡板间距及堵塞率对PEMFC传质特性和输出性能的影响。在流道出口处添加挡板,可强化流道内反应气体传质效果;增大挡板间距或提高挡板堵塞率,均能提高扩散层中的氧气浓度,改善PEMFC输出性能。提出一种挡板数量为5、间距为0.90 mm、间距差值为0.40 mm、堵塞率为75.00%及堵塞率差值为2.50%的挡板分布设计方案。与无挡板流道相比,该方案的峰值功率密度提高了4.96%。

A reasonable structure of the flow channel in bipolar plate was of great significance to improve the performance of proton exchange membrane fuel cell(PEMFC).The three-dimensional model of a single straight flow channel PEMFC was established,the rectangular baffles were added at the outlet of the channel.The effects of baffle spacing and blockage rate on the mass transfer characteristics and output performance of PEMFC were researched.The mass transfer effect of the reaction gas in the flow channel could be strengthened by adding baffles at the outlet of the flow channel.Increasing the baffle spacing or blocking rate could improve the oxygen concentration in the diffusion layer and the output performance of PEMFC.A baffle distribution design with a baffle number of 5,a spacing of 0.90 mm,a spacing difference of 0.40 mm,a blocking rate of 75.00%and a blocking rate difference of 2.50%was proposed.Compared to non-baffled flow channel,the peak power density of proposed scheme was increased by 4.96%.