三元锂离子电池多目标热优化

Multi-objective thermal optimization of ternary lithium-ion battery

锂离子电池的产热对其安全性和寿命有很重要的影响。本文基于COMSOL Multiphysics平台,针对51 A·h三元软包层叠式锂离子电池,提出了其与电极对耦合的三维电化学-热耦合有限元分析模型,结合响应面法研究正极厚度、极板宽度、正极极耳厚度、正极极耳宽度、负极极耳厚度、负极极耳宽度6个设计参数对温度场的影响,通过线性加权组合法和随机梯度下降法,求得降低电池平均温升和最大温差的最优方案。结果表明,正极厚度对温度场影响较大,与温升正相关,但是厚度小到一定程度后影响减弱。极板宽度与极耳尺寸的增加能降低放电末期电池的温升;其数值在一定范围内时,电池的最大温差达到最小值。这套优化方案误差小于2.68%,平均温升降低2.93℃,最大温差降低0.596℃,有助于提高电池的安全性和寿命,为其他电池的多目标热优化提供了参考。

The heat production of the lithium-ion battery has a very important impact on its safety and life.Based on COMSOL Multiphysics,this study proposes a three-dimensional electrochemical thermal coupled finite element analysis model for a 51 A·h laminated lithium-ion pouch battery.The effects of six design parameters on the temperature field(i.e.,positive electrode thickness,plate width,positive electrode tab thickness,positive electrode tab width,negative electrode tab thickness,and negative electrode tab width)are studied using the response surface method.The linear weighted sum and random gradient descent methods are used to obtain the optimal scheme to reduce the average temperature rise and the maximum temperature difference of the battery.The average temperature rise and the maximum temperature difference of the battery can be reduced by using the random gradient descent method.The results show that the positive electrode thickness greatly influences the temperature field positively related to the temperature rise;however,the influence is weakened when the thickness is reduced to a certain extent.The increase of the plate width and the tab size can reduce the temperature rise of the battery at the end of the discharge.In addition,the maximum temperature difference of the battery reaches the minimum value within a certain range.The error of the scheme is less than 2.68%.The temperature rise is reduced by 2.93℃.The temperature difference is reduced by 0.596℃,which is helpful in improving the safety and life of the battery,and provides a reference for the multi-objective thermal optimization of other batteries.