高电流密度下薄膜PEMFC自润湿特性研究

STUDY ON SELF-HUMIDIFYING PROPERTIES OF THIN-MEMBRANE PEMFC AT HIGH CURRENT DENSITY

为研究薄膜质子交换膜燃料电池在高电流密度下的自润湿特性,使用FLUENT建立三维多物理场稳态模型,并用实验结果验证模型的可靠性。研究发现:随着电流密度的增加,水分布均匀性会提高,1200 mA/cm^(2)为薄膜可实现自润湿的电流密度临界点,高于此电流密度时薄膜中可实现良好的自润湿。在高电流密度下,阴极的加湿会加剧局部水淹现象并导致电池性能下降。降低温度、增加背压及减小膜厚会提升膜的自润湿特性,且膜厚对薄膜的自润湿特性影响最为显著。

To study self-humidifying properties of thin-membrane proton exchange membrane fuel cells at high current density,a three-dimensional,multi-physical steady-state model is established via FLUENT in this study.The simulation results are validated by the experimental data to ensure the reliability of the present model.It is found that with the increase of current density,the uniformity of water vapor distribution is improved.The critical point of the self-humidifying current density of the thin-membrane is 1200 mA/cm^(2),and the self-humidifying in the thin-membrane can be achieved well.The external humidification of the cathode aggravates the local flooding phenomenon and leads to the degradation of the cell performance at high current density.Decreasing the temperature and membrane thickness,increasing the operation pressure can improve the self-humidifying properties of the membrane.The thickness of membrane has the most significant effect on the self-humidifying properties of the thin-membrane.