PEM燃料电池阴极中的液态水及其影响因素

阴极多孔介质中液态水的含量对PEM燃料电池阴极中的传质及其性能具有极其重要的影响。提出了一个二维、两相、稳态数学模型,研究PEM燃料电池阴极中两相水的传递及其对电池性能的影响。模型耦合了连续方程、动量方程和组分守恒方程,并将质子膜中的净水迁移通量作为边界条件之一来处理。通过实验的方法和数值模拟的方法,研究了电池操作压力和温度对电池性能的影响,同时验证了模型的有效性。模拟发现:提高操作压力和升高阴极加湿温度使电池阴极催化剂层(CTL)和扩散层(GDL)界面上的液态水含量大幅提高;升高阳极加湿温度,电池阴极CTL和GDL界面上的液态水含量变化不明显;而升高燃料电池的操作温度,阴极CTL和GDL界面上液态水的含量降低。

LIQUID WATER IN PEM FUEL CELL CATHODE AND ITS INFLUENCING FACTORS

Liquid water saturation in the cathode porous electrode plays an important role in PEM fuel cell performance and mass transport. In this paper, a steady-state two-dimensional, two-phase flow mathematical model for PEM fuel cell is presented. The model couples continuity equation, momentum equation and species conservation equations. Net water transport flux in the membrane is considered as a boundary condition. The effect of fuel cell temperature and pressure on its performance is investigated by experiment and simulation. The modeling results compared well with the experimental data. The results of simulation showed that the liquid water saturation on the interface between the cathode CTL and GDL increases significantly with the increase of fuel cell pressure and the cathode humidification temperature,the effect due to the increase in the anode humidification temperature is negligible, and the saturation decreases with the increase of fuel cell operation temperature.