Abstract:

A three dimensional model was proposed to study water transport phenomena in the membrane as well as the performance of PEMFC under various relative humidity(RH)of anode inlet gas.This model couples the conservation equations of the water concentration in membrane and the catalyst layer using a set of internal boundary conditions at the interface.The model was realized based on the COMSOL software and the simulated polarization curves are found in good agreement with the experiments thus confirming the validity of the model.The numerical results show that the humidification strongly influences the current density so as to affect the cell efficiency.Under low humidification conditions of anode inlet gas,the membrane current density below rib is greater than the gas flow channel,however,under the high humidity conditions,membrane current density distribution is uniform.Using thicker film,such as Nafion 117,the membrane of anode side has the potential of dehydration under high current density even if anode inlet gas be humidified.

Key words: PEM, fuel cell, humidification, current density distribution, numerical simulation

摘要：

针对质子交换膜中水分布不均匀造成燃料电池性能降低的问题,将膜和催化层中水传递方程进行耦合实现水在膜和催化层之间连续传递,建立了质子交换膜燃料电池三维稳态模型。利用有限元分析软件COMSOL进行模拟计算,研究了阳极气体在不同湿度下膜电流密度分布并组装单电池进行了验证,分析实验模拟结果表明:模拟极化曲线与实验极化曲线吻合良好。湿度对电流密度分布影响很大,低湿度条件下,脊背下方电流密度大于气体流道下方;高湿度条件下,电流密度分布比较均匀;采用Nafion117较厚膜时,高电流密度下,即使阳极加湿,阳极侧也有脱水的可能。

关键词: 质子交换膜, 燃料电池, 增湿, 电流密度分布, 数值模拟