动态机车工况下质子交换膜燃料电池电堆衰退性能分析

Degradation Performance Analysis of Proton Exchange Membrane Fuel Cell Stack under Dynamic Locomotive Conditions

为探究质子交换膜燃料电池(PEMFC)电堆在动态机车工况下的衰退性能,该文结合极化曲线、等效电路模型(ECM)方法和弛豫时间分布(DRT)方法对电池进行分析。针对5kW电堆,测量了机车工况下运行0h、110h、220h及330h后,第1、20和40片电池的极化曲线和电化学阻抗谱(EIS)。建立PEMFC三阶等效电路模型,根据模型参数分析PEMFC内部变化。计算EIS相应的DRT,根据不同波峰解释PEMFC各极化过程的变化。结果表明:该电堆不同单片的主要损耗都发生在氧气还原反应过程和质量传输过程中,但动态工况下不同单片的衰退趋势不一致。电堆入口的电池1在110~220h期间衰退速率最快,电堆中间的电池20衰退速率随时间逐渐加快,电堆出口电池40在220~330h期间衰退速率最快。且由于电池40在0h未活化完全,导致其在0~110h期间出现性能提升。

To explore the degradation performance of proton exchange membrane fuel cell(PEMFC)stack under dynamic locomotive conditions,polarization curve,equivalent circuit model(ECM)method,and distribution of relaxation time(DRT)method are combined to analyze the performance of PEMFC.For the 5kW stack,the polarization curves and electrochemical impedance spectroscopy(EIS)of the 1st,20th,and 40th cells after 0h,110h,220h,and 330h of locomotive operation are measured.The third-order equivalent circuit model of PEMFC is established,and the internal changes of PEMFC are analyzed according to the model parameters.The DRT corresponding to EIS is calculated to explain the changes of the polarization process of PEMFC according to different peaks.The results show that the main losses of different cells occur in the oxygen reduction reaction process and mass transfer process,while the degradation trends of different cells are inconsistent under dynamic conditions.Cell 1 at the stack inlet degrades the fastest during 110~220h.The degradation rate of cell 20 increases with time.Cell 40 at stack outlet degrades the fastest during 220~330h.Due to cell 40 is not fully activated at 0h,its performance is improved during 0~110h.