非水系锂空气电池放电过程模拟

Simulation of discharge process of non-aqueous lithium air battery

针对非水系锂空气电池多孔电极内物质传输及电极反应过程建立多物理场耦合数学模型,考虑两种不同的放电产物生长模式,分别建立了产物形态模型和电子通道模型。比较了两种产物模型的放电电压-比容量关系曲线,发现基于电子通道模型预测的不同倍率下的电池性能与实验结果吻合更好,并通过模拟研究了电池不同放电阶段的氧气浓度分布、产物厚度分布、多孔正极孔隙率分布、活性比表面积和液相电势分布等演化规律。

A multi-physics coupling mathematical model was developed for reactant transport and electrochemical reaction during the discharge process of non-aqueous lithium air batteries.Two different models,the product-morphology model and electron-tunneling model,were proposed for describing the influence of the discharge product.The model curves of discharge voltage with specific capacity under different discharge current were compared.The results show that the predicted battery performance at different rates based on electron-tunneling model is in good agreement with experimental results.The oxygen concentration distribution,thickness distribution of the product,porosity distribution of porous electrode,active specific surface area and liquid electrolyte potential distribution were numerically investigated at different stages during the discharge.