气体扩散层孔隙率梯度对质子交换膜燃料电池水管理的影响

程植源，周荣良，李嘉颀，纪嘉树，闫伟^*

山东大学能源与动力工程学院，山东 济南  250061

摘要：为了研究孔隙率对气体扩散层（gas diffusion layer，GDL）内水分布的影响，使用COMSOL Multiphysics软件构建质子交换膜燃料电池（proton exchange membrane fuel cell，PEMFC）模型，以单一孔隙为0.4的GDL为基准，设计小梯度双层、大梯度双层、4层梯度3种不同GDL分布结构，对其极化曲线和水含量进行仿真分析。结果表明：相比基准GDL，具有梯度结构的GDL可以有效防止“水淹”现象发生，并能在一定程度上提升电池性能；在平均孔隙率相同时，可以通过加大孔隙率梯度或增加孔隙率梯度分层数量来提高电池阴极侧的排水性能，从而提升电池电流密度；使用具有较大梯度分布与较多梯度分层的GDL能有效提升燃料电池的水管理效率和电池性能。该研究可以有效解决燃料电池的“水淹”问题。

关键词：PEMFC；GDL；水摩尔分数;孔隙率梯度

Effect of porosity gradient of gas diffusion layer on water management of PEMFC

CHENG Zhiyuan, ZHOU Rongliang, LI Jiaqi, JI Jiashu, YAN Wei^*

School of Energy and Power Engineering, Shandong University, Jinan 250061, China

Abstract：In order to study the effect of porosity on the water distribution in the gas diffusion layer(GDL), a proton exchange membrane fuel cell(PEMFC) model is built by COMSOL multiphysics software. The GDL in the porosity of 0.4 is taken as benchmark. Three different GDL distribution structures are designed, including two layers′ GDL with low gradient and high gradient, coupling with a four layers′ GDL with certain gradient. Their polarization curves and water content are simulated and analyzed. The results show that compared with the GDL of benchmark, the GDLs with gradient structure can effectively prevent “water flooding” and improve the performance of the PEMFC. With the same average porosity, the drainage performance of the cathode side of the battery can be improved by increasing the porosity gradient or the number of layers of the porosity gradient, so as to improve the current density. Using GDL with larger gradient distribution and more gradient stratification can effectively improve the water management efficiency and cell performance of fuel cells.Therefore, this research can provide a reference for solving the problem of fuel cell flooding.

Keywords:PEMFC; GDL; mole fraction of water; porosity gradient