1 kW自呼吸PEMFC堆控制因素试验

Experimental Study on Control Factors for a 1kW Airbreathing PEMFC Stack

摘要:

自呼吸质子交换膜燃料电池(PEMFC)阴极侧湿度和温度耦合严重,且空气流量对湿度和温度影响不同,从而使得对电池输出电压的控制变得复杂.以氢气压力和提供阴极空气流量的风扇转速为影响因素,对相应的工作点集进行了正交试验研究.分析结果表明,风扇转速高于极值电压转速时,空气会带走更多的水分,从而使得质子交换膜逐渐干燥,阻抗增大,电池性能衰减; 风扇转速低于极值电压转速时,空气流量带走的热量减少,使得阴极表面温度升高,阴极端相对湿度迅速减低,从而导致质子交换膜迅速干燥,电池性能衰减迅速.因此,每个工作点存在一个使电池电压最高的风扇转速值.

Abstract:

In an airbreathing proton exchange membrane fuel cell (PEMFC),the air flow effect is different on the strongly coupled temperature and humidity,and uncertain on the stack voltage.To study the stack performance in detail,the inlet hydrogen pressure and the rotation rate of fans are investigated as effect factors,and the orthogonal experiments are carried out at the corresponding working points.The results show that,when the fans rate is above the optimal value,the air takes more water from the cathode away and the membrane becomes dried slowly,and then membrane impedance increases,therefore the stack voltage declines; in the other hand,when the fans rate is below the optimal value,the heat quantity carried out with air is reduced,making the cathode surface temperature higher,the air relative humidity decreases rapidly,and then the membrane dries quickly,therefore the stack voltage drops sharply.Therefore,there is an optimal fans rate value which makes the stack voltage highest at each working point.