Modeling And Simulation Of Membrane Electrode Of Proton Exchange Membrane Fuel Cell

As the demand for clean energy grows rapidly, proton exchange membrane fuel cell(PEMFC) technology is seen as a viable candidate for an alternative energy conversion device because it has high conversion efficiency, high energy density, environmental protection and many other advantages. Despite much research progress in the past two decades several remaining technical challenges as cost, performance and others must be overcome for the successful commercialization of PEM fuel cells. Through simulation method, the mechanism of material transfer, optimizing the structure of the cell, can effectively reduce the research and manufacturing costs, is one of the important methods in the research of proton exchange membrane fuel cell.In the research of PEMFC, Material transfer and chemical reactions in catalyst layer are the hot spots and the agglomerate model is widely used in complex models. the influence of liquid water in the model of agglomerate catalyst layer is mainly concentrated on the influence to the porosity of the catalyst layer, but the effect of the agglomerate itself is seldom studied. In this paper, the effect of liquid water on the structure of agglomerate is introduced, a two dimensional gas liquid two-phase flow with structure parameters of agglomerate catalyst cathode model is established.The results show that the water film that surrounding the agglomerate surface can hinder the diffusion of oxygen and the thickness of water film can be calculated, which leads to the rapid decrease of the output voltage of PEMFC polarization curve at high current density and the limited current density will be drop. The influence of Pt loading, diffusion layer porosity and inlet pressure on the performance of PEMFC was analyzed by using the model. The results show that the amount of platinum load is proportional to the cell voltage at middle current density, and is inversely proportional to the limited current density. Its value takes 0.35~0.4mg/cm2;the porosity of gas diffusion layer may in 0.4~0.6; Inlet pressure should in 1~3atm and other conclusions.