系统考察质子交换膜燃料电池组装(锁紧力,0.45~11.3 MPa)对其性能和寿命的影响,并确定了最佳锁紧力.以最佳锁紧力(3.2 MPa)的单电池作2000 h寿命测试,根据该单电池不同运行时间下的极化和功率曲线分析,得到与其活化区对应的电化学参数.XRD检测表明,电池组装施加的锁紧力不但影响电池的接触电阻,而且还影响由MEA微观结构决定的电池反应动力学性能.在最佳锁紧力作用下运行2000 h后的单电池在大电流密度区出现了明显的性能衰减,这主要是由于催化剂的团聚效应引起的.但在非最佳锁紧力作用下,阴极催化剂的团聚作用远大于阳极催化剂.

The lifetime performance was investigated by assembling the single cell of PEMFC under a series of holding forces ranging from 0.45 to 11.3 MPa and reassembled under optimal holding force.The polarization and power density curves were obtained during different periods of operating time up to 2000 hours and the fuel cell catalyst activation regions in the polarization curves were analyzed to evaluate the electrochemical kinetic parameters.The results revealed that the holding forces affected not only the internal contact resistances,but also the kinetic parameters which might be caused by the change of the MEA microstructures.The apparent degradation observed at higher current densities after 2000 h lifetime test under the optimal holding force of 3.2 MPa was due mainly to the increases of the catalyst particle sizes.However,the agglomeration in the particle sizes of cathode catalyst after 2000 h lifetime test at 3.2 MPa was less severe than that without optimal assembly force control.