Purge strategy analysis of proton exchange membrane fuel cells based on experiments and comprehensive evaluation method

To maintain a constant performance of the cells and stack is crucial in open cathode proton exchange membrane fuel cell (PEMFC) for unmanned aerial vehicle (UAV) applications. The consistencies of cell voltage and the output power of the stack are effective indicators for evaluating the performance. Therefore, the purge strategy is investigated experimentally in this study. The results show that a longer purge interval results in a slower response speed of the individual cell, leading to a deterioration of the stack voltage and output; on the other hand, a longer purge duration results in a decrease of the stack output, but gradually improves the performance of the cell closer to the anode. Based on these findings, combined with the analysis of cell voltage and stack power data, and validated by the comprehensive evaluation method (Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)), optimal purge strategy for balancing the performance of the cells and stack in our case study is obtained, which are the purge interval and duration time are at 10 s and 90 ms, respectively. The method proposed by this paper can be used to design an effective purge interval and duration of open cathode PEMFC to achieve constant performance of cells and stacks.