基于真实孔隙结构的质子交换膜燃料电池氢空吹扫研究

Study on Proton Exchange Membrane Fuel Cell Hydrogen Air Purge Based on Real Pore Structure

摘要:

停机吹扫是提高燃料电池低温启动成功率的重要方法，为此建立了质子交换膜燃料电池（PEMFC）二维瞬态模型，重点研究氢空吹扫策略下PEMFC的停机吹扫过程。基于蒙特卡洛算法构建气体扩散层（GDL）真实孔隙结构、PEMFC各个守恒方程、离聚物气相转移相关方程，用于研究不同吹扫气体湿度对吹扫速度、吹扫结束后膜结合水含量的影响，以及GDL真实孔隙结构对停机吹扫阶段GDL内部传质现象的影响规律。研究结果表明：吹扫气体湿度的降低能够有效地促进停机吹扫过程中膜结合水的气相转移，从而使最终水含量降低；真实孔隙结构能够更加真实的解释停机吹扫过程中水气传质规律。

关键词:质子交换膜燃料电池（PEMFC）;停机吹扫;气体扩散层（GDL）;真实孔隙;膜结合水含量

Abstract:

Fuel cell shutdown purge is an important method to improve the success rate of cold start. In this paper， a two-dimensional transient proton exchange membrane fuel cell （PEMFC） model is established to study the shutdown purge process of PEMFC under the hydrogen air purge strategy. Based on the GDL real pore model， PEMFC related conservation equation and ionomer gas phase transfer equation， the influence of the different humidity of purge gases on the purge speed and the membrane-bound water content after the purge， and the influence of the real pore structure of GDL on the internal mass transfer phenomenon of GDL during the shutdown purge stage were studied. The results show that the decrease in humidity of purge gas can effectively promote the gas phase transfer of membrane-bound water during the shutdown blowing process， thereby reducing the final water content； the real pore structure can provide a more realistic explanation of the transfer rule of water and gas during purge.

Key words:proton exchange membrane fuel cell (PEMFC);shutdown purge;gas diffusion layer (GDL);real pore;membrane-bound water content