锂离子电池三维电化学-热耦合模型及生热分析

Three dimensional electrochemical thermal coupling model and heat generation analysis of lithium-ion batteries

锂离子电池在放电过程中的温度变化会影响电池的工作性能,严重时还会引起安全事故。建立了3.4V/50Ah磷酸铁锂电池的三维电化学-热耦合模型,能获得比单一模型更精确全面的电池温度场分布及其动态变化的情况。模拟了电池0.5C、1C和2C恒流放电工况下温升变化以及三维温度场分布。随着放电倍率的增大,锂离子电池内部呈不均匀化,电池最高温度变大,温度场的不均匀性越大,温升速率越高,温差越大;电池越靠近中心的部分温度越高,最高温度出现在电池几何中心位置,极柱温度最低,正极柱温度略高于负极柱。

The high temperature change of the lithium ion battery during the discharge process will affect the performance of the battery,and in some serious cases,it may cause a safety accident.A three-dimensional electrochemical-thermal coupling model of 3.4 V/50 Ah lithium iron phosphate battery was established,which could obtain a more accurate and comprehensive battery temperature field distribution and dynamic change than a single model.The temperature rise and the three-dimensional temperature field distribution of the battery at 0.5 C,1 C,2 C constant current discharge conditions were simulated.As the discharge rate increases,the discharge platform becomes lower and the discharge performance becomes worse.The interior of the lithium ion battery is not uniform,and as the discharge rate increases,the maximum temperature of the battery becomes larger,and the unevenness of the temperature field increases.The higher the temperature rise rate,the larger the temperature difference;the higher the temperature of the battery near the center,the higher the temperature appears at the geometric center of the battery,the lowest terminal temperature,and the positive column temperature is slightly higher than the negative terminal.