PEMFC电极孔隙率的优化研究

对质子交换膜燃料电池单体建立了三维稳态电化学模型,考察了气体扩散层孔隙率对电池性能的影响,验证了扩散层孔隙率及层厚的变化反映从气体通道到扩散层和催化剂层的反应气体扩散量,进而影响电化学反应的活跃程度;以膜与阴极催化剂层界面处获得的最大电压为目标函数,采用鲍威尔搜索法对气体扩散层孔隙率进行数值优化,得到了扩散层孔隙率和层厚的最优值。通过优化前后氧气浓度和电流密度的对比显示,这些参数可以显著改善电极的传质性能,使燃料电池获得最佳性能。

Optimizing effects of diffusion layer porosity on PEMFC

A three-dimensional steady-state electrochemical mathematic model of a single PEMFC(polymer electrolyte membrane fuel cell) was established to investigate the effect of GDL(gas diffusion layer) porosity on the cell performance. It is found that the magnitude of porosity and thickness of GDL have significant influences on the gas amount transferred from the gas channel to the catalyst layer,which corresponding to electrochemical reaction activation.By applying the Powell algorithm,the optimum values of porosity and thickness of GDL were obtained from the optimization solution with respect to the objective function,which is defined as the maximum potential at the membrane/cathode interface.By comparing the optimized oxygen mole fraction and the local current density distribution with the reference case,the cell performance was improved because the transport limitation was decreased through GDL optimization.