宽温域下固态锂离子电池倍率性能的建模与仿真

Modeling and Simulation of Rate Performance of Solid-State Lithium-Ion Batteries over a Wide Temperature Range

摘要: 固态锂离子电池相对液态电池不但提升电池的能量密度，而且解决传统液态电池漏引起爆炸的安全问题。由于离子电导率低、固–固界面反应速率差，导致固态锂电池的倍率性能较差，固态电池的倍率性能不能满足实际应用的需求，成为目前发展的瓶颈。针对宽温域的环境和倍率性能对固态电池性能影响，本文采用COMSOL多物理场仿真软件对正极为钴酸锂(LCO)、负极为金属锂(Li)及固态电解质为锂磷氧氮(LiPON)的固态电池进行建模仿真。通过三次电流分布、固体传热、稀物质传递等接口实现多物理场的耦合进行固态电池的倍率性能仿真，研究固态锂离子电池分别在60℃、40℃、20℃、0℃、−5℃、−10℃、−15℃和−20℃不同温度下的电池自身温度的变化、电池倍率性能及锂离子的浓度分布。详细讨论探究改变电解质厚度以及阴极厚度使得锂离子传输距离减少提升锂离子工作效率达到对电池倍率性能的影响。仿真结果表明适当减少锂离子传输距离提升传输效率，能有效提升固态电池的倍率性能。本文研究固态锂电池在高温环境下的倍率性能以及提出一种在低温环境下提高固态电池倍率性能的方法，对固态电池的结构设计指导和工程价值。

Abstract: Solid state lithium-ion batteries not only increase the energy density of batteries compared to liquid batteries, but also solve the safety problem of explosions caused by leakage in traditional liquid batteries. Due to low ion conductivity and poor reaction rate at the solid interface, the rate performance of solid-state lithium batteries is poor, and the rate performance of solid-state batteries cannot meet the needs of practical applications, becoming a bottleneck in current development. In response to the impact of wide temperature range environment and rate performance on the performance of solid-state batteries, this paper uses COMSOL multi physics field simulation software to model and simulate solid-state batteries with lithium cobalt oxide (LCO) as the positive electrode, lithium metal (Li) as the negative electrode, and lithium phosphorus oxygen nitrogen (LiPON) as the solid electrolyte. This study simulates the rate performance of solid-state batteries by coupling multiple physical fields through interfaces such as three current distributions, solid heat transfer, and dilute material transfer. And it studies the temperature changes, rate performance, and concentration distribution of lithium ions in solid-state lithium-ion batteries at different temperatures of 60˚C, 40˚C, 20˚C, 0˚C, −5˚C, −10˚C, −15˚C, and −20˚C. Detailed discussion and exploration of the impact of changing electrolyte thickness and cathode thickness on reducing lithium ion transport distance and improving lithium ion work efficiency on battery rate performance. The simulation results show that reducing the transmission distance of lithium ions appropriately to improve transmission efficiency can effectively enhance the rate performance of solid-state batteries. This article studies the rate performance of solid-state lithium batteries in high-temperature environments and proposes a method to improve the rate performance of solid-state batteries in low-temperature environments, providing guidance and engineering value for the structural design of solid-state batteries.