【摘要】 为了考察直接液体甲醇燃料电池(DMFC)中扩散层和催化层的结构参数对电池性能的影响,建立了二维、单相、全电池模型.模型中综合考虑了电化学动力学、水动力学、化学反应和各种组分传递的耦合过程以及甲醇窜流在阴极形成的寄生电流,对阳极催化层和阴极催化层传质过程引入了团聚块模型进行修正.利用此模型,通过自主开发的计算程序,计算了扩散层、催化层的厚度和孔隙率对电池输出性能及甲醇窜流的影响.计算结果表明:相对于催化层而言,电池性能在更大程度上依赖于扩散层的参数.在不同的电池输出电流密度下,扩散层厚度对电池输出性能有不同的影响趋势,应在考虑其他参数的基础上选择合适的扩散层厚度,以获得较优的电池输出性能.大的孔隙率可减小传质阻力,但在提高电池输出性能的同时会加重甲醇窜流.更多还原

【Abstract】 A two-dimensional single phase full cell model for a direct methanol fuel cell(DMFC) is developed to investigate the effects of structure parameters,such as the porosity of diffusion layer(DL) and catalyst layer(CL),and the width of DL and CL,on cell performance and methanol crossover rate.In this model,the electrochemical kinetics,hydrodynamics,fluid flow and methanol crossover are considered.The agglomerate models are utilized for both anode catalyst layer and cathode catalyst layer to modify the methanol oxidation reaction kinetics and the oxygen reduction reaction kinetics.A program based on the finite volume method is coded to solve the equations,and the results show that the cell performance depends strongly on the parameters of DLs rather than CLs.The trend in the effects of DL width is reversed for different cell current density.Although a higher porosity of DL and CL leads to a better cell performance,the methanol crossover becomes heavier.更多还原