关键词: 质子交换膜燃料电池, 冷启动, 传递过程, 过冷水, 数值模拟

Abstract:

Cold start is quite important for the commercialization of proton exchange membrane fuel cell (PEMFC). In PEMFC cold start experiment, super-cooled water inside the cell has been observed by neutron imaging technology. Here, we have proposed a model to address the effects of super-cooled water on the PEMFC cold start performance. By introducing the icing probability function to describe the randomness of freezing process, we established a three-dimensional, transient and multi-phase mathematical model. The PEMFC cold start performance was investigated with various ionomer volume fraction in cathode catalyst layer (CL) and membrane thickness. The results showed that increasing the ionomer volume fraction in cathode CL could effectively promote the diffusion of product water from the cathode CL into the membrane, and thus water storage space inside the membrane could be utilized more efficiently. Moreover, reducing the membrane thickness helps to enhance the diffusion of ionomer water from the membrane into the anode CL, thereby alleviating the anode dehydration phenomenon at high current density.

Key words: proton exchange membrane fuel cell, cold start, transport processes, super-cooled water, numerical simulation