常规流场下各向异性扩散层对质子交换膜燃料电池(PEMFC)性能影响

为了研究扩散层各向异性对电池性能的影响,以XD=Di,j ^y/Di,j ^x 为各向异性的表征,建立了使用常规流场的质子交换膜燃料电池二维传质模型.考虑了阴阳极内物质的对流和扩散、水和质子在膜内传递以及催化层的电化学反应.利用有限差分法对控制方程进行离散,采用逐次超松驰法求解得到了阴阳极反应气体和水的浓度分布以及催化层电流密度、膜中水含量、膜中电势和电流密度的分布.分析结果表明：在1≤XD≤4时增大XD有利于提高电池性能,但随着XD增大其对电池性能的影响逐渐减小;并且XD对电池性能的影响主要体现在对阴极和膜性能的影响上,其对阳极性能的影响甚微.

The Effect of Anisotropic Diffusion Layer on the Performance of PEMFC with Conventional Flow Field

To investigate the effect of anisotropy(denoted by XD = Di y , j /Dix ,j) in diffusion layer on the performance of proton exchange membrane fuel cells (PEMFC) with conventional flow field, a two-dimensional model was presented. The flow and diffusion in gas diffusion layer, electrochemical reactions in catalyst layer, proton and water transfer in membrane were considered. The partial differential equations describing the above phenomenon were discreted by finite difference method and solved by Successive Over Relaxation method. The U-I curves, the distribution of reactant concentration and water vapor concentration in cathode and anode, current density, water content and potential in proton exchange membrane, and the current density in catalyst layer were obtained. It shows that as XD increasing from 1 to 4, the PEMFCs performance is improved, however, the effect of XD on performance becomes weaker and weaker with the XD increasing; and XD mainly affects the performance of cathode and membrane, but have little effect on anode.