高湿环境下质子交换膜燃料电池停机恢复的实验研究

To address the reversible performance degradation of polymer electrolyte membrane fuel cells (PEMFC)due to deteriorating water management in a high-humidity environment,the mechanism of how the duration of shutdown regulates performance recovery was investigated. Twenty runs of 80-hour accelerated aging tests and a 300 hour experiment on recovery from shutdown were carried out on eight cell stacks.The duration of shutdown was set to short-term (1 h),overnight (more than 10 h),and long-term (more than 72 h).Quantitative measurements of the half-power and full-power voltage attenuation and membrane electrode parameters were made；a log-linear mathematical model was established based on the relationship between the recovery effect and time,with logarithmic, linear and constant factors contributing to the recovery taken into account；and the contribution rate ofeach factor type was analyzed.The research found that single-stage accelerated aging led to a full-power voltage attenuation of 8.31% and a half-power voltage attenuation of 2.46%；long-term shutdown enabled complete recovery of full-power voltage from reversible degradation caused by accelerated aging in the period,with a recovery rate of 110%,and had an effect on degradation accumulated over time；the recovery rates in case of overnight and short-term shutdowns were 65% and 50%,respectively；the core contributor to recovery evolved over time；recovery from short-term shutdowns mainly relied upon the direct effect of hydrogen infiltration/purging,and recovery from long-term shutdowns mainly depended on water management optimization and ionomer rearrangement；under high-humidity conditions,the performance degradation of PEMFC was largely reversible,while in case of long-term shutdowns,full recovery from degradation in the period and partial recovery from degradation accumulated over time were achieved through water management optimization and ionomer rearrangement.The insights presented in this research can provide quantitative support for maintenance strategies of on-board PEMFC systems subject to frequent start-stop cycles.