直接甲醇燃料电池动态性能的研究

直接甲醇燃料电池用作移动电源时，电池的动态响应特性特别重要。该文作者利用自行设计的直接甲醇燃料电池测试系统对一有效面积为50cm^2的直接甲醇单体燃料电池的动态性能进行了实验研究。通过计算机控制电池负载的动态变化。实验研究了电流变化不同波形及各种波形下加载电流大小、斜率变化对电压信号动态响应的影响。结果表明电池电压对各种电流变化的响应很快。动态负载时电池的开路电压要比稳态运行时的高，主要原因是因甲醇窜流造成的过电势的减少。电池内部电化学反应与传质瞬态变化的综合作用对电池动态运行有着关键的影响。

STUDY OF DYNAMIC PERFORMANCE OF A DIRECT METHANOL FUEL CELL

Dynamic response of direct methanol fuel cell is very important for the transportable applications. The experiments of the transient response of a single direct methanol fuel cell with 50cm2 active area were performed on a test system with a computer-controlled electronic load. The influence of shapes of current loading cycles including rectangle,triangle and trapezium and magnitude and slope of increasing current on the cell voltage response were studied. The results reveal that the cell responds rapidly to variable current change. The open circuit voltage of the cell under dynamic operating is higher than that under steady state owe to the reduction of mixed potential caused by methanol crossover. The interactions between transient behaviors of mass transfer and electrochemical reactions inside fuel cell significantly affect the dynamic operation of the direct methanol fuel cell.