PEMFC水含量的在线表征及暂态过程分析

摘要

采用电流线性扫描的方法,研究了暂态条件下PEMFC内氧还原反应(ORR)生成水量对电池性能的影响.利用微探针方法探讨了不同操作条件下燃料电池中膜内水含量的变化情况.结合电化学交流阻抗技术以及相关经验公式,分析了暂态条件下燃料电池MEA内水的扩散特性.结果表明,暂态过程中电流与电压之间的响应在秒级以内,而燃料电池的高频阻抗(HFR)变化相对于电流存在着明显的滞后现象(对于Nafion212在15～20 s).此外,还就燃料电池的吹扫操作进行了探讨研究.并对实验结果进行了理论分析和解释.%The influence of water generation due to the oxygen reduction reaction on the performance of PEMFC was investigated by a linear sweep method. The water content under different operating conditions was also obtained by using a micro-probe. The transient characteristics of water transport in the MEA were analyzed by Electrochemical Impedance Spectroscopy (EIS) technique. The results show that the transient response between the current and voltage is less than 1 s, but the transient response of the internal resistance lags the current with a value of about 15-20 s. The effect of purging operation on the transient response of the PEMFC has also been explored.