基于NSGA-Ⅱ的锂电池液冷扁管结构设计与热性能优化研究

Structural design of liquid cooled flat tube for lithium battery and optimization of thermal performance based on NSGA-Ⅱ

文中提出了一种锂电池模组蛇形液冷扁管空间并行交叉液冷结构,对液冷结构参数进行了优化。以电池最高温度和最大温差为优化目标,以液冷扁管高度为优化变量,采用拉丁超立方法(Latin Hypercube Sampling,LHS)对优化变量建立80组参数化组合样本,以CFD瞬态数值仿真计算,结合Kriging代理模型与NSGA-Ⅱ(Non-dominated Sorting Genetic AlgorithmⅡ)多目标遗传算法对液冷结构参数进行寻优求解,并进一步研究了冷却液入口速度对液冷结构散热性能的影响。结果显示:相对单层蛇形液冷扁管结构,蛇形液冷扁管空间并行交叉结构有更好的冷却性能,在冷却液入口流速为0.02 m/s时,电池1C放电工况下最高温度和最大温差分别下降3.2%和19.3%,电池2C放电工况下最高温度和最大温差分别下降6.4%和18.3%;在冷却液入口流速降低时,蛇形液冷扁管空间并行交叉结构的散热性优势更明显。

In this article,a serpentine liquid cooled flat tube structure characterized by the cross-parallel space is proposed for the lithium battery modules,and the parameters of the liquid cooled structure are optimized.With the battery’s maximum temperature and temperature difference as the optimization objectives,and the liquid cooled flat tube’s height as the optimization variables,80 sets of parameterized composite samples are worked out by means of Latin Hypercube Sampling(LHS)for the optimization variables.The CFD transient numerical simulation is performed;the Kriging Surrogate Model and the NSGA-Ⅱ(Non-dominated Sorting Genetic AlgorithmⅡ)multi-objective genetic algorithm are combined to optimize the liquid cooled structure’s parameters.Efforts are made to explore the influence of the flow rate at the coolant inlet on the liquid cooled structure’s heat-dissipation performance.The results show that compared with the single-layer serpentine liquid cooled flat tube structure,the serpentine liquid cooled flat tube structure characterized by the cross-parallel space has better cooling performance.When the flow rate at the coolant inlet is 0.02 m∕s,the maximum temperature and the maximum temperature difference with the battery 1C discharge decrease by 3.2%and 19.3%,respectively;the maximum temperature and the maximum temperature difference with the battery 2C discharge decrease by 6.4%and 18.3%,respectively.When the flow rate at the coolant inlet is declining,the serpentine liquid cooled flat tube structure characterized by the cross-parallel space will have more obvious advantage of heat-dissipation performance.