不同集流方式下对称双阴极固体氧化物燃料电池的电-化-热-力数值模拟及失效分析

Electro-Chemical-Thermal-Mechanical Numerical Simulation and Failure Analysis for the Double Side Cathode Solid Oxide Fuel Cell Stack Units with Different Collecting Positions

本文围绕新型对称双阴极固体氧化物燃料电池电堆单元在不同集流位置下热应力分布情况和优化集流方式,建立了一个基于电-化-热-力多场耦合理论的三维SOFC电堆单元数值模型.引入固体力学热-力学理论,结合Weibull失效概率分析方法,讨论了不同集流方式对SOFC内部应力分布及失效的影响.研究结果表明,双侧阴极同时开展电子集流方式下的电解质平均电流密度比单侧单一集流方式下高,改变阳极集流位置会改变电极高温区的分布;SOFC电堆单元上电极结构处的最大主应力明显大于其他组件上的最大主应力;阳极集流位置设置在阳极气体入口处时电极结构上的最大主应力和失效概率大于集流位置设置在阳极气体出口处的最大主应力和失效概率.

In this work, a three-dimensional numerical model for the double side cathode solid oxide fuel cell(DSC-SOFC) is established by the finite element method based on the electro-chemo-thermal-mechanical multi-physics coupling theory. Using this model, the thermal stress distribution and optimization on the current collection scheme of the developed DSC-SOFC are investigated. In this study, the thermodynamic model is combined with the Weibull failure probability theory to study the influence of the collecting position on the thermal stresses and the failure of the DSC-SOFC. The results show that the average current density of the double side current collection is higher than that of the single side current collection, and different positions of the anode current collections result in the different distributions of the electrode temperature. Furthermore, the maximum principal stress at the electrode structure of the SOFC is significantly higher than those on other components. When the anode current collection position is set at the anode gas inlet, the maximum principal stress and the failure probability are larger than the case when the anode current collection position is at the anode gas outlet.