基于格子Boltzmann方法的燃料电池阳极气体与离子传输分布研究

Simulation study of anode gas and potential distribution of fuel cell based on lattice Boltzmann method

格子玻尔兹曼方法(Lattice Boltzmann Method,LBM)适用于模拟研究固体氧化物燃料电池(Solid Oxide Fuel Cell,SOFC)复杂多孔阳极内电化学反应过程中微观粒子的传输活动。利用X射线纳米CT成像技术获得SOFC阳极样品在运行2 h和20 h后的三维结构,并在原有研究基础上,利用LBM方法模拟研究增加离子传输对阳极电化学反应的影响,获得阳极内氢气、水的浓度分布和氧离子电流密度分布。结果表明:电池运行20 h后,阳极微结构发生明显变化,有效三相界面长度减少,模拟反应过程中氢气消耗减少,氧离子消耗减少,SOFC的效率降低。通过研究SOFC阳极电化学反应过程中微结构变化、气体与电流密度分布,可以为阳极结构优化提供参考。

[Background]The lattice Boltzmann method(LBM)is suitable for studying the transport of microscopic particles in the complex porous anode electrochemical reaction process of solid oxide fuel cell(SOFC).[Purpose]This study aims at the microstructure change,gas and current density distribution in the process of SOFC anode electrochemical reaction in order to understand the cause of performance attenuation in the process of battery operation and provide reference for the optimization of anode structure.[Methods]First of all,the three-dimensional structure of SOFC anode samples after running 2 h and 20 h were obtained.Then,based on previous studies,the ion transport effects in the electrochemical reaction of anode was performed by using LBM to obtain the concentration distributions of hydrogen and water in anode,and the current density distribution of oxygen ions.[Results]After 20 h of SOFC operation,Ni particles migrate and aggregate,resulting in the increase of local Ni phase volume fraction and the decrease of effective three-phase interface length of anode.As the electrochemical reaction occurs at an effective three-phase boundary,the reduced length of the three-phase interface results in a reduction of SOFC performance.At the same time,as fuel cells run,hydrogen consumption decreased,oxygen ion consumption decreased,and water production decreased.[Conclusion]It is shown that LBM can be used to simulate an SOFC anode at microscale and evaluate the effect of structural parameters on the transport processes.