质子交换膜燃料电池大电流密度下运行工况优化研究

Optimization of Operating Conditions for PEMFC Running at Large Current Density

利用计算流体动力学软件,针对在大电流密度、阴极无加湿、阳极加湿,阴阳极有背压等操作特点下运行的PEM电池进行数值模拟,综合考虑电池性能和电流密度分布的均匀性,寻求最优工况点.结果表明,对于给定的操作压力,存在一个最佳性能温度,压力增加,最佳温度随之增加,在压力为100,200,300kPa时,最佳性能温度分别为75,60,50℃;由于阴极不加湿,在最佳性能温度点膜含水量分布及电流密度分布不均匀;在较低温度下运行时电流密度分布均匀性随着压力的增加逐渐提高,但在较高温度下运行时则相反.

Considering the performance and uniformity of the current density distribution, CFD soft- ware is used in this paper to simulate the PEM cells, which operate at large current density, no cath- ode humidification but full anode humidification, and baekpressure, to seek for the optimized operat- ing point. The main conclusions are as follows： for a given operating pressure, there is an optimal temperature which makes the fuel cell have the best performance, and the optimal temperature increa- ses with the pressure; the best temperatures for 100,200 and 300 kPa are 75,60 and 50 ℃, respective- ly. Since the cathode is not humidified, the membrane water content distribution and current density distribution are not uniform at the optimum performance temperature point; the current density distri- bution uniformity increases with pressure at lower temperatures, but it has the opposite trend at high- er temperatures.