全固态锂金属电池多物理场耦合下的电化学过程仿真模拟

Simulation of the Electrochemistry Process with the Coupling of Multiple Physical Fields for All-solid-state Lithium Batteries

基于COMSOL Multiphysics多物理场仿真软件对氮氧化锂磷(LiPON)基全固态锂金属电池进行有限元模拟.使用3次电流分布、稀物质传递、固体传热与固体力学等接口实现了多物理场在固态锂电池体系内部的耦合,并完成了对于全固态锂金属电池本身在给定物理参数的情况下实际运行的电化学性能仿真.在此模型中,电池在运作时的热管理以及应力分布均得到有效的计算.利用锂金属负极表面沉积的数据分析得到了锂枝晶生长的可能原因.结果表明,全固态锂电池的容量衰减以及枝晶生长等安全管理的失控并不只是单一因素控制的结果;体系的浓度梯度、应力预分布、传热传质过程的控速步骤与充放电过程的体积变化等都会对电池的性能与安全管理产生不同的影响.

The finite element simulation of lithium phosphorus oxynitride(LiPON)-based all-solid-state lithium batteries is performed based on COMSOL Multiphysics which is a Multiphysics simulation platform.Utilizing the interfaces of tertiary current distribution,dilute substance transfer,solid heat transfer and solid mechanics,the coupling of multiple physical fields in the solid-state battery system is realized.At the same time,the electrochemical performance simulation for the all-solid-state lithium battery itself under given physical parameters is also completed.In this model,the thermal management and stress distribution of the battery during operation are effectively calculated.The deposition data on the lithium anode surface was used to analyze the possible causes of lithium dendrite growth.The results showed that the capacity decay of an all-solid lithium batteries and the safety management out of control such as dendrite growth are not just the result of single factor control.The system’s concentration gradient,pre-stress distribution of stress,the speed-control step of heat and mass transfer processes and volume change during the charge and discharge process will all have different effects on battery performance and safety management.