Parameter optimization of PEMFC stack under steady working condition using orthogonal experimental design

Operating parameters have a huge impact on the output characteristics of a proton exchange membrane fuel cell stack. In this study, to optimize the performance of proton exchange membrane fuel cell stack, 4 sets of operating parameters, which include working temperature, cathode stoichiometric, relative humidity, and backpressure, were optimized by means of the orthogonal experimental design. The experiment was developed with the help of 4-factor and 3-level orthogonal table. Nine orthogonal experiments were performed, and the polarization curve, local current density distribution, and electrochemical impedance spectroscopy of each experiment were obtained. It is observed that cathode stoichiometric and working temperature have much stronger effects on the output voltage and output consistency of stack than that of relative humidity and backpressure. Using comprehensive equilibrium method, the optimized combination of each parameter was achieved as follows: the working temperature was 75 degrees C, cathode stoichiometric was 2.5, relative humidity was 50%, and backpressure was 1 bar. The on-site test result showed that when the cathode stoichiometric was low, and some part of the stack would be in a starvation condition and when the temperature was low, it might cause mass transfer problems.