循环工况研究PEMFC单体电池电压的一致性

Analysis of cell voltage uniformity of PEMFC under on cyclic conditions

基于功率为4.5 k W燃料电池堆的台架动态循环工况试验,研究质子交换膜燃料电池(PEMFC)堆单体电池电压的一致性。选用熵值法对循环工况中的电流密度进行权重分析,选出开路电压、怠速功率、15%额定功率及额定功率对应的特征电流密度,并对单体电池电压一致性变化规律进行整体分析,验证特征电流密度可替代循环工况中的不同电流密度点,反映单体电池的电压一致性。利用统计学参数变异系数和相对极差来衡量单体电池的电压一致性,发现在大电流密度及长时间运行时,电压一致性明显变差。性能最差时,变异系数为3.1%,相对极差为9.4%。

Based on the dynamic cycle condition test of a 4. 5 k W fuel cell stack,the voltage uniformity of individual cell in proton exchange membrane fuel cell( PEMFC) stack was studied. The entropy value method was used to analyze the weight of current densities under cycle condition. The corresponding current densities of open circuit voltage,idle power,15% rated power and rated power were selected,then the variation law of voltage uniformity of individual cells was overall analyzed. It was verified that the characteristic current density point could replace whole current density points under cycle conditions,which reflected the voltage uniformity of individual cells. The statistical parameter variation coefficient and relative range were used to characterize the voltage consistency of individual cells. It is found that the voltage uniformity was worse at the high current density point and with a longrunning process. The variation coefficient was 3. 1% and the relative range was 9. 4% in the worst performance.