气体扩散层厚度对PEMFC性能的影响

Effect of GDL thickness on PEMFC performance

质子交换膜燃料电池(PEMFC)的气体扩散层(GDL)厚度对燃料电池的输出性能有重要影响。文章利用多物理场直接耦合分析软件(COMSOL Multiphysics 5.0),在电池温度为70℃的条件下,对4种不同厚度的GDL进行模拟分析,并在相同的操作条件下,得到了4组极化曲线、阴极氧气浓度、阴极水浓度、阳极氢气浓度以及电流密度的变化趋势图。对比分析4组变化趋势图后发现:GDL的厚度越小,燃料电池的性能越好;GDL的厚度对阳极氢气的浓度分布影响不大;当GDL的厚度增大时,产生的液态水会堵塞GDL的孔隙,降低GDL的孔隙率。

The thickness of gas diffusion layer （GDL） of proton exchange membrane fuel cell （PEMFC） has an important influence on the output performance of fuel cell. Four kinds of GDL with different thickness were simulated and analyzed, at the temperature of 70 ℃, by the direct coupling analysis software （COMSOL Muhiphysics 5.0）. Under the same operating conditions, the trend curves of the four groups of polarization curves, the concentration of cathode oxygen, the concentration of cathode water, the concentration of hydrogen and the current density of anode were obtained. Compared with the four groups, it was found that the thinner the thickness of GDL, the better the output performance of the fuel cell. The concentration distribution of anodic hydrogen is not affected by the thickness of GDL. When the thickness of GDL increases, the pores of GDL is blocked by the produced liquid water and the porosity of GDL is reduced.