质子交换膜燃料电池密封系统热力耦合仿真研究

Thermodynamic Coupling Simulation Study of Proton ExchangeMembrane Fuel Cell Sealing System

温度影响质子交换膜燃料电池(PEMFC)的密封性能和力学行为,因而影响其使用寿命和可靠性。为研究PEMFC在热力耦合下的密封性能和力学行为,建立PEMFC单电池和多电池结构的二维模型,研究密封系统在不同工作温度下的应力-应变分布,讨论橡胶密封圈压缩比、双极板错位和密封垫尺寸对PEMFC密封性能和力学性能的影响。结果表明:温度对密封圈的Mises应力和膜电极组件(MEA)框架接触压力有很大影响;在不同工作温度下单电池和多电池结构的密封性能相似,应力和接触压力分布差别也不大,因此单电池结构的研究结论可以推广到多电池结构;随着橡胶密封圈压缩比和密封圈尺寸的增加,燃料电池密封性能得到改善;而双极板错位会加剧MEA框架的变形;高应力区出现在橡胶密封圈的横截面内部,容易导致局部应力集中和密封失效。

Temperature affects the sealing performance and mechanical behavior of proton exchange membrane fuel cell(PEMFC),thus affecting their service life and reliability.To study the sealing performance and mechanical behavior of PEMFC under thermodynamic coupling,two-dimensional models of PEMFC single-cell and multi-cell structures were established to study the stress-strain distribution of the sealing system at different operating temperatures.The effects of rubber sealing ring compression ratio,bipolar plate misalignment and sealing gasket size on the sealing performance and mechanical properties of the PEMFC were discussed.The results show that temperature has a significant effect on the Mises stress of the sealing gasket and the contact pressure of the membrane electrode assembly(MEA)frame.The sealing performances of single-cell and multi-cell structures at different operating temperatures are similar,and the differences in stress and contact pressure distribution are not significant.Therefore,the research conclusion of single-cell structure can be extended to multi-cell structure.The fuel cell sealing performance is improved with increasing compression ratio and size of the rubber sealing ring.The misalignment of the bipolar plates exacerbates the deformation of the MEA frame.The high stress area appears inside the cross section of the rubber sealing ring,which can easily lead to local stress concentration and sealing failure.