质子交换膜燃料电池阴极扩散特性的数值分析

Numerical Analysis of Diffusion Characteristic in the Proton Exchange Membrane Fuel Cell

针对交指型质子交换膜燃料电池阴极,采用通用Darcy定律来描述多孔介质内的流体流动,建立一个二维的稳态的多组分的传输模型.通过求解模型,得到电极内的压力、速度、质量分数分布,并讨论进、出口之间压差、电极厚度和电极肋条宽度的改变对电池性能的影响.结果表明:随着进、出口之间压差的增加,电流密度是增大的,但是增大的幅度是逐渐降低的;电极厚度存在一个最优值,该值依赖于电极结构和气体分配器的设计参数;采用窄的电极肋条有利于提高电池的性能.

A two-dimension, steady-state, multi-component transport model is presented to investigate the cathode performance of a proton exchange membrane fuel cell with an interdigitated gas distributor. Darcy law is used to describe the flow in the porous media. Subsequently, the model is applied to predict the pressure, velocity and mass fraction distributions in the electrode and explore the effect of the change of differential pressure between the inlet and the outlet, electrode thickness and rib width on the performance of fuel cell. The results show that： current density creases with the higher differential pressure between the inlet and outlet, but the increment is diminishing; electrode thickness has an optimum value which depends on the electrode morphology and the gas distributor design parameters; using narrower elec~ trode rib can improve the performance of fuel cell.