电动汽车锂离子电池组内散热特性的数值模拟

摘要

锂离子电池组涉及数据规模庞大,传统方法无法有效实现对其散热特性的研究,为此,提出一种新的通过数值模拟方式研究电动汽车锂离子电池组内散热特性的方法.介绍了锂离子电池组工作原理,分析了锂离子电池的充放电过程.通过雷诺平均法进行雷诺时均处理,获取电动汽车锂离子电池组内散热控制方程和湍流方程.介绍了初始和边界条件,通过CFD实现控制方程的求解.依次进行了锂离子电池表面散热特性数值模拟、不同风孔大小下电池组散热特性数值模拟、不同倍率充放电后电池组散热特性数值模拟以及不同环境温度下电池散热特性数值模拟.实验结果表明,锂离子电池中心垂直截面和上下壁面的温度分布均为中心最高,壁面较低,壁面温度梯度大,热量散失速度快;在风孔大小和出口大小相近,充放电倍率为1C时,电动汽车锂离子电池组内散热性最佳;环境温度越低,电池温度升高幅度越大,散热性能越好.%Lithium ion battery relates to large scale data, traditional methods can not effectively realize the re-search on the heat transfer characteristics of this, a new method of heat transfer performance of lithium-ion batteries for electric vehicles in the group was put forward by numerical simulation method.The working principle of Li ion battery pack was introduced, and the charging and discharging process of Li ion battery was analyzed.Reynolds av-eraged method is used to deal with Reynolds averaged time temperature control equations and turbulence equations for lithium-ion batteries in electric vehicles.The initial and boundary conditions are introduced, and the control equations are solved by CFD.In order to simulate heat dissipation characteristics of lithium-ion cell, surface heat transfer numerical simulation, numerical simulation, battery cooling characteristics of different wind hole size under the numerical simulation of heat dissipation characteristics of battery charge and discharge at different rates and dif-ferent temperatures are carried out.The experimental results show that the lithium ion battery center vertical section and the upper and lower wall temperature distribution center are the highest, the wall is low, the wall temperature gradient, heat dissipation speed; in the wind hole size and the export of similar size, charge and discharge rate of 1C, lithium ion batteries for electric vehicle in the best heat dissipation; the lower the ambient temperature, the higher the battery temperature, the better heat dissipation performance.