锂离子电池组散热设计及送风策略

通过实验研究了锂离子电池1C倍率放电,20℃自然对流情况下的温升特性。测得了20℃环境温度下电池的充放电内阻特性,并根据某品牌18650型锂离子电池的物性参数以及实验测得的内阻数据建立了电池单体仿真模型,仿真计算了与实验同工况下的温度分布情况,最大误差4.9%。设计了一种包含480节电池的并行通风空气冷却散热结构,并通过正交试验进行了优化,得到了进出风孔距电池的最小距离1mm,上挡板距离电池的最小距离1mm,下挡板距离电池的最小距离1mm的最优结构,使电池组的最大温升下降了5.71℃,最大温差降低了5.06℃。并基于最优结构给出了120s后每60s改变送风方向的往复送风策略,使电池组即使在40℃、2C放电的恶劣工况下也能够工作在25℃-40℃,电池单体温差5℃以下的工作环境中。

Study on Heat Dissipation Structure and Strategy of Lithium Ion Battery

The temperature rise characteristics of lithium-ion battery under 1 C rate discharge and natural convection at 20℃ were studied. The internal resistance characteristics of the battery at 20℃ were measured. According to the physical parameters of a brand 18650 lithium-ion battery and the internal resistance data measured in the experiment, the cell simulation model was established. The temperature distribution under the same working condition as the experiment was simulated and calculated, and the maximum error was 4.9%. A parallel ventilation air cooling and heat dissipation structure with 480 batteries was designed, and optimized by orthogonal test. The optimal structure of the minimum distance between the air inlet and outlet holes, the minimum distance between the upper baffle plate and the battery, and the minimum distance between the lower baffle plate and the battery were obtained, which reduced the maximum temperature rise of the battery by 5.71℃ and the maximum temperature difference by 5.06℃. Based on the optimal structure, the strategy of changing the direction of air supply every 60 s after 120 s is given, which can make the battery work in the working environment of 25℃-40℃ and the temperature difference of single cell below 5℃ even in the bad condition of 40℃ and 2 C discharge.