车用燃料电池堆低温停机吹扫试验研究

An Experimental Study on Low Temperature Shutdown and Purging of Vehicle Fuel Cell Stack

质子交换膜燃料电池停机吹扫是保证电池在低温环境下安全存储与正常启动的重要方法。为实现快速停机吹扫,且满足-40℃无损存储与低温启动的要求,本文首先构建了吹扫过程水平衡模型,对吹扫过程水的产生和移除进行分析;其次,对吹扫主要参数进行敏感性分析,确定了电池温度为强敏感性参数,增湿温度为中敏感性参数,气体流量为弱敏感性参数;再次,对吹扫结果进行30次-40℃/60℃的冻结/解冻循环试验,并对试验后电池进行物理形貌和电化学分析;最后,进行了-40℃低温启动验证。结果表明,通过对吹扫参数的优化大幅缩短了低温停机吹扫时间,吹扫后的电池在-40℃低温存储后性能未见衰减,形貌无明显变化,且吹扫后的电池能够实现-40℃低温启动。

Gas purging during shutdown is an important method for proton exchange membrane fuel cells to ensure the safe storage and normal cold start in a low temperature environment.In order to achieve the quick shutdown purging,and meet the requirement of -40℃ non-destructive storage and cold start,relevant research is carried out in this paper.Firstly,a water balance model is established to analyze the generation and removal of water during the purge process.Secondly,the sensitivity analysis of the main parameters of shutdown purge is carried out,and it is determined that the cell temperature is a strong sensitive parameter,the humidification temperature is a medium sensitive parameter,and the gas flow is a weak sensitive parameter.Thirdly,30 freezing/thawing cycles at -40℃/60℃ are carried out on the purge results,and the physical morphology and electrochemical analysis of the fuel cell after the test are carried out.Finally,the -40℃ cold start is carried out to verify whether the purging results can meet the requirements of -40℃ start-up.The results show that the low temperature purge time during shutdown is greatly shortened by optimizing the purging parameters.The performance of the fuel cell stack does not degrade and the physical morphology does not change significantly after storage at -40℃,and the fuel cell stack can achieve cold start at -40℃.