(沈阳建筑大学，机械工程学院，沈阳110168)
摘 要: 通过制备锂空气电池用电极，并对电极进行CT断层扫描得到了电极的实际结构。将电极数值孪生模型与数值仿真模型结合，构建了基于实际孔隙结构的锂空气电池二维模型。针对锂空气电池放电过程中不同放电电流密度条件下，Li2O2生成速率、Li2O2体积分数、氧气浓度、电极孔隙率，过电势等参数在放电过程中的变化进行分析。研究发现，引入数值孪生孔隙结构的模型可以更直观的展现出放电过程中电极孔隙被堵塞、氧气传输效率下降的过程。放电临近截止时，氧气的持续填充导致电极中局部孔隙中氧气浓度急剧上升。随着放电进行，反应区域逐渐变小，氧气流入侧反应速率明显提升。而后，电极极化加剧，放电终止。本文对锂空气电放电过程中物质的变化有着指导作用。
关键字: 锂空气电池；电极孔隙结构；数值孪生模型
（School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang,110168, China）
Abstract:The carbon fiber electrode for lithium-air batteries is fabricated, and the pore structure of the electrode is obtained by CT tomography. A two-dimensional model of organic lithium-air battery based on the pore structure is developed by combining the digital twin model of the actual electrode structure with the numerical simulation model.The changes of the formation rate of Li2O2, volume fraction of Li2O2, oxygen concentration, electrode porosity, overpotential and other parameters during the discharge of lithium-air battery under different discharge current densities were analyzed. It is found that the lithium-air battery model with digital twin structure can more intuitively show the process that the electrode pores are blocked and the oxygen transport efficiency decreases during discharge. When the discharge is close to the cut-off, the oxygen concentration in the local pores of the electrode rises sharply due to the continuous filling of oxygen. With the discharge, the reaction area becomes smaller and the reaction rate on the oxygen inflow side increases obviously. This situation is particularly obvious in the small pore size of the electrode. Then, the electrode polarization intensifies and the discharge stops. This paper has an intuitive guiding role for the material changes in the process of lithium-air electric discharge.
Key words: lithium-air battery; electrode pore structure; digital twin model
