低温工况下燃料电池性能衰减及策略优化

Performance Degradation and Strategy Optimization of PEMFCs Under Subfreezing Temperature

摘要:

利用极化曲线、电化学阻抗谱（EIS）、循环伏安（CV）及分区测试技术等表征手段，从不同角度对质子交换膜燃料电池（PEMFC）在低温（＜0 ℃）存储和启动工况下的性能衰减进行研究.结果表明：停机过程无气体吹扫的情况下，冻结/解冻循环导致PEMFC极化阻抗增加，电流密度衰减，催化剂电化学活性面积（ECSA）减少，以及分区电流密度分布均匀性下降，直接影响了PEMFC耐久性；基于优化的二次吹扫策略，可在更少吹扫气体用量下，增强吹扫除水效果；通过水浴加热辅助，在340 s内成功实现单电池-30 ℃低温冷启动.

Abstract:

Polarization curve, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and segmented cell techniques were adopted to investigate the performance degradation of proton exchange membrane fuel cell (PEMFC) during storage and startup processes under subfreezing temperatures(<0 ℃). The experimental results indicate that freeze/thaw cycles without gas purge during shutdown process will increase the polarization resistance and deteriorate the current density output of PEMFC. In addition, the electrochemical surface area (ECSA) of catalyst layer decreased and the uniformity of current density distribution of PEMFC worsened, which deteriorates the overall durability of PEMFC. Based on the optimized twicepurge strategy, the efficiency of residual water removing was enhanced with less gas consumption. With the aid of circulating coolant heating solution, the cold start of single cell from -30 ℃ was successfully achieved within 340 s.