PEM燃料电池低温环境启动过程中水热平衡研究

The Study of Water and Heat Balance on Low-temperature PEMFC Startup

PEM燃料电池堆低温启动问题是燃料电池电动汽车商业化过程中必须克服的障碍.建立了低温环境下电池堆启动阶段水热平衡的集中质量模型,分析了电池低温启动时,环境温度、外加热源、启动电流,以及催化层结构和成分对启动性能的影响.在计算条件下,认为从-20℃启动需要外加热源进行预热,启动电流不宜过大;加大催化层Nafion含量和厚度对冷启动影响明显,可以延迟孔隙中水开始结冰及被冰塞满的时间.

Cold start of proton exchange membrane fuel cell（PEMFC）stack from subzero temperature is one of the obstacles which must be overcome before its commercialization.A lumped mass model is developed for the water and thermal equilibrium for the cold start process of PEMFC stack,the effects of the environment temperature,external preheat source,cold start current and the structure and Nafion content of cathode catalyst layer（CL）are analyzed.It can be concluded that an external preheat source is needed when a PEMFC stack cold start from-20℃and the operating current should not be too large.Besides,increasing the Nafion content and thickness of the CL have obvious effect on cold start,which can both postpone the time when the water begins to freeze and the time when the pores are filled with ice.