Dynamic behavior study on voltage and temperature of proton exchange membrane fuel cells

Transient characteristic is one of the important indicators for evaluating the dynamic performance of fuel cells. In this paper, an air-cooled proton exchange membrane fuel cell stack with a dead-end anode was experimentally tested to investigate its transient behavior at different step currents. During the experiment, the undershoot phenomenon was observed and the oscillation law of voltage at different stages was found. The possible influencing factors were discussed. Meanwhile, the temperature variations of the different cross-sections and different single cells were also analyzed in detail by the temperature readings of the 30 thermocouples embedded in the cathode flow channels. Furthermore, in order to compare the difference in the dynamic performance of the stack under different operating conditions, the related parameters, such as voltage fluctuation rate and temperature fluctuation rate, were introduced. This article helps to better understand the dynamic response mechanism of fuel cells and evaluate its dynamic performance.