燃料电池内电流趋肤效应现象浅析

Study on the skin-effect phenomena in PEM fuel cells

燃料电池的耐久性和寿命是制约其商业发展的重要问题,特别是在动态负载环境下,电池的性能衰减与寿命变短问题更加突出。介绍了首次利用麦克斯韦电磁理论研究电池内部电流分布,并从理论上阐述电池在动态负载输出时,电池内电流密度分布不再均匀,且随着电流变化频率的增加,电流密度越来越向电池外围集中的现象,即电流的趋肤效应:从电池的实际运行与负载取电模式,说明了燃料电池产生电流趋肤效应的情况。最后还通过对单电池作了简化模拟分析,从数据上说明了当负载变化频率大于1kHz时,电池内部将产生严重的电流趋肤效应。说明了电流趋肤效应是燃料电池在动态负载环境下性能衰减与寿命变短的重要原因之一。

The major obstacle for the PEM （proton exchange membrane） fuel cell commercialization is the durability. Especially during the dynamic status, attenuation of cell performance becomes stronger. In this paper, Maxwell theory and Fourier transformation are used to analyze the skin-effect in PEM fuel cell. Using these theories, it demonstrates that, the current density distribution in PEM fuel cell is not symmetrical. Wben the cell works at dynamic status, the skin-effect makes current density denser at the edge while it is sparser in the center. Also, a mathematical calculation is used to analyze a single cell. Results indicate that the skin-effect in PEM fuel cells is obvious when the frequency of load changing is I kHz. Generally, the skin-effect may be one of the important reasons for the performance attenuation of PEM fuel cell when it works at dynamic status.