不同衰退机理对PEMFC怠速工况性能衰退影响的模拟研究

分析质子交换膜燃料电池(PEMFC)怠速工况衰退机理,确定怠速工况不同衰退机理对燃料电池模型参数的影响,采用所建立的PEMFC二维等温多物理场模型,仿真研究燃料电池在怠速工况衰退前后的性能及各种衰退因素对电压衰减量的贡献和内部反应气体分布变化。研究结果表明,阴极活化损失增大是怠速工况下最重要的衰退因素,其次是开路电压衰退,影响最小的是阴极电化学活性面积衰退;在相同操作条件下,衰退后燃料电池的最低氧气摩尔浓度和最低氢气摩尔浓度上升,电流密度分布不均匀现象加剧。

SIMULATION STUDY ON EFFECT OF DIFFERENT AGING MECHANISMS ON PEMFC PERFORMANCE DEGRADATION UNDER IDLING CONDITION

In this paper,the degradation mechanisms of PEMFC idling conditions are analyzed,and the influence of the different degradation mechanisms of idling conditions on the parameters of the fuel cell model are identified. Using the established twodimensional isothermal multi-physical model for the PEMFC,the performance of the fuel cell before and after the degradation under idling conditions and the contribution of various degradation factors to the voltage attenuation and the change of internal reaction gas distribution are simulated. The results show that the increase in cathode activation loss is the most important degradation factor under idling conditions,followed by open-circuit voltage(OCV)degradation,and the least impact is the cathode ECSA degradation. Under the same operating conditions,the minimum oxygen molar concentration and the minimum hydrogen molar concentration of the fuel cell increase and the current density maldistribution increases after the degradation.