International Journal of Hydrogen Energy ( IF 7.2 ) Pub Date : 2020-05-20 , DOI: 10.1016/j.ijhydene.2020.04.139 P. Moçotéguy , B. Ludwig , D. Beretta , T. Pedersen
Water management is critical for PEMFCs, especially at system level. To study its impact on the performance and obtain useful indicators for fault detection, two commercial stacks were characterized by impedance spectroscopy under various humidities and current densities. One was fresh while the other was operated on-field during 10 000 h. Four capacitive and one inductive loops are identified. The capacitive loops are attributed to charge transfer kinetics at both anode and cathode and to cathodic and anodic mass transfer limitations. The inductive loop is attributed to oscillations in the ionomer water content induced by oscillations in the amount of produced water during the measurement. The size of the cathodic charge transfer loop and its departure angle at high frequencies increase as humidity decreases because the ionomer conductivity decreases. These parameters are potential indicators of the cathode drying. The angles are below 45° at low humidities but close to 90° in sur-saturated conditions.
中文翻译:
用阻抗谱研究水管理对PEMFC商业烟囱性能的影响
水的管理对于PEMFC至关重要,尤其是在系统级。为了研究其对性能的影响并获得用于故障检测的有用指标,通过在不同湿度和电流密度下的阻抗谱对两个商用堆栈进行了表征。一个是新鲜的,而另一个则在10000 h内进行了现场操作。确定了四个电容性回路和一个电感性回路。电容性回路归因于阳极和阴极的电荷转移动力学以及阴极和阳极的质量转移限制。感应回路归因于在测量过程中离聚物水含量的振荡,该离聚物水含量的振荡是由产水量的振荡引起的。由于离聚物电导率降低,随着湿度的降低,阴极电荷传输环路的尺寸及其离开角在高频下会增加。这些参数是阴极干燥的潜在指标。在低湿度下,角度小于45°,但在过饱和条件下,角度接近90°。