PEMFC气体扩散层内各向异性传递过程数值模拟

质子交换膜燃料电池(PEMFC)气体扩散层(GDL)具有各向异性属性,常规数值模拟对GDL采取均匀模型,忽略了各向异性传递过程对PEMFC性能的影响。本文发展了一个三维非等温单相模型,在GDL平面内和GDL厚度方向采用不同的传递系数,模拟了各向异性传递系数对PEMFC整体和局部性能的影响。在本文计算条件下,GDL各向异性和均匀模型模拟得到的电池极化曲线几乎完全相同,但电池电流密度分布和温度分布等局部特性存在很大差异。该结果进一步证明了不能单独用极化曲线来验证电池数学模型的正确性。

Numerical Investigation of the Anisotropic Transport Process Within PEM Fuel Cell

The gas diffusion layer(GDL) of proton exchange membrane fuel cells(PEMFCs) exhibits strong structural anisotropy in through-plane and in-plane direction.However,the GDL has usually been simplified as a homogeneous porous structure in numerical modeling,and the anisotropic property of GDL is ignored.In this paper,a three dimensional.non-isothermal,single-phase model with different transport coefficients in through-plane and in-plane direction of the GDL is developed to investigate the effects of anisotropic transport characteristics of GDL on cell performance.From the results,it is found that although the overall cell performance is similar,local distributions,such as local current density and temperature,from the two models are significantly different.The results prove that only the polarization curve is not enough to verify the correctness of a simulation model.