Elucidation of the degradation factor distribution in one cell on Polymer Electrolyte Fuel Cells

阐明了质子交换膜燃料电池一个单元内的降解因子分布，并将所提出的诊断方法应用于四分单元的原型。结果表明，电流扫描方法存在以下问题：各分段电极的内阻差异对暂态响应影响较大，扫描电流时实际电极内的电流密度分布不能反映在诊断结果中。因此，诊断从当前的扫描方法改为未收到上述影响的当前中断方法。由此，可以识别出膜的干湿状态下的阻力参数以及分离器与气体扩散层之间的接触状态。此外，这种改进的诊断方法被应用于沿气流方向为四次的单元格。结果，由于在消耗氢和氧等反应物的出口附近，源于第二/第三RC电路的参数变大，而来自第一RC电路的参数变小，如果上述诊断准确度能够提高，则可以通过改进的诊断来阐明PEFC上一个单元中的退化因子分布。

The degradation factor distribution in one cell on PEFC was elucidated by which the proposal diagnostics apply to the prototype of quadrisection cell. As a result, the current sweep method had several problems that transient response was greatly influenced according to the difference of internal resistance in each segmented electrode, and the current density distribution in an actual electrode cannot be reflected in the diagnostics result when the current was swept. Therefore, the diagnosis was changed from the current sweep method to the current interruption method of not receiving the above-mentioned influence. As a result, the parameters of the resistance, which originated in the drying/humid condition of membrane, and the contact condition between the separator and the gas diffusion layer, can be identified. Moreover, this improved diagnostics was applied to the cell quadrisected in direction of gas flow. As a result, because the parameter originated in the 2nd/3rd RC circuit becomes large and the parameter originated in the 1st RC circuit becomes small near outlet where reactants such as hydrogen and oxygen are consumed, the degradation factor distribution in one cell on PEFC can be elucidated by the improved diagnostics if the above-mentioned diagnostics accuracy can be improved.