全尺寸大面积PEMFC模拟及应用研究

Simulation and Application of the Full-scale Large-area PEMFC

质子交换膜燃料电池(PEMFC)中传输现象及电化学反应是一个多维、多相、多尺度的动态复杂过程。与超算中心合作,利用CFD软件,对具有实际流场结构的全尺寸大面积PEMFC进行模拟,研究了流场结构对反应气体、水浓度、电流密度等的分布状态的影响,以及气体加湿度、操作压力和进气方式对电池性能的影响。结论认为,在正常条件下运行时,阴极流场板空气供应决定着催化层电化学反应的速率,因此以阴极流场板气体分布均匀性考察电流密度分布的均匀性,而不求解电化学方程,在一定条件下是简单、可行同时合理的。沿阴极流动方向,流速逐渐增加,流道内液态水体积分数逐渐增大,催化层内的电流密度和温度则逐渐减小。增加背压可以显著提高电池性能;阴极气体湿度在50%时电池性能最好。研究结果应用于25kW电堆的制造与运行,效果良好。

The transfer phenomenon and electrochemical reaction in proton exchange membrane fuel cell(PEMFC)is a multi-dimensional,multi-phase and multi-scale dynamic and complex process.In cooperation with the supercomputing center,CFD software was used to simulate the full-scale large-area proton exchange membrane fuel cell(PEMFC)with real flow field structure.The effects of flow field structure on the reaction gases,water and current density distribution,and the effects of gas inlet humidity,operating pressure and air inlet mode on the performance were studied.It was concluded that under normal operation conditions,the air supply of cathode flow field plate determines the electrochemical reaction rate of catalyst layer.Therefore,it is simple,feasible and reasonable to investigate the uniformity of current density distribution by using the gas distribution uniformity of cathode flow field plate instead of solving the electrochemical equations under certain conditions.Along the flow direction of the cathode,the flow rate increases,the volume fraction of liquid water in the channel increases,while the current density and temperature in the catalyst layer decrease.The results show that increasing the back pressure can significantly improve the performance of the battery,and the performance of the battery is the best when the cathode gas humidity is 50%.The results are applied to the fabrication of 25 kW stack and the results are good.