Study on the degradation of proton exchange membrane fuel cell under load cycling conditions

Abstract

In order to study the changing regularity of proton exchange membrane fuel cell (PEMFC) performance in the aging process under load cycling condition and improve the durability of fuel cell, the orthogonal experiment method was introduced. In this paper, three-factor and three-level orthogonal experiments were set up to study the influence of upper potential limit (UPL), lower potential limit (LPL) and period of the load cycle on the degradation rate of fuel cell. The test results show that under variable load cycling conditions, the fuel cell performance decays first fast and then slowly. The degradation rate after hundreds of hours of load cycling experiment is usually less than 50% of that of the fresh fuel cell. The dominant factor which effect the degradation mostly significantly changes during the whole aging process. According to the influence degree of three factors on performance degradation rate, the degradation process can be divided into three stages: the UPL dominating stage, the LPL dominating stage and the slow decay stage. In order to mitigate the performance degradation, the UPL in the optimal combination should be as low as possible at all the three stages. The optimized parameters can reduce the degradation rate by more than 50%. The load cycling condition should be avoided at the initial stage after the fuel cell is put into use. And the lifespan of aged fuel cell because of loading cycling can be prolonged through work more under the conditions which will not lead to serious activation potential loss and ECSA loss.