新能源动力电池系统高效热管理技术研究

Research on Efficient Thermal Management Technology of New Energy Power Battery System

摘要: 在“双碳”目标的推动下，新能源汽车产业迅速发展起来，新能源汽车的核心部件动力电池，其性能和寿命直接决定整车的发展。锂离子电池对温度非常敏感，在高倍率充放电工况下很容易产生局部热量积聚，加速容量衰退甚至引发热失控。本文提出了一种协同热管理架构，即采用液体冷却系统和柔性复合相变材料相结合的方式，同时，验证了一种基于润湿网格设计的新型超薄均热板在模组局部热点散热中的应用潜力。经过实验测试，5C高倍率放电下，该协同系统把模组最高温度控制在48.1℃，比自然冷却模组(72.55℃)和纯相变冷却模组(62.6℃)分别低24.45℃和14.5℃，模组内部最大温差保持在3℃左右，满足温差小于5℃的均温要求。另外发现具有65μm润湿网格图案的超薄均热板在61.6%的最佳注液率时扩散热阻降低至0.058℃/W，可以很好地实现高功率密度电池模组局部热点管理的组件级方案。

Abstract: Driven by the goal of “double carbon,” the new energy automobile industry has developed rapidly. The performance and life of power battery, the core component of new energy vehicles, directly determine the development of the whole vehicle. Lithium-ion batteries are very sensitive to temperature. Under high-rate charging and discharging conditions, it is easy to produce local heat accumulation, accelerate capacity fading and even cause thermal runaway. In this paper, a collaborative thermal management architecture is proposed, which combines a liquid cooling system and a flexible composite phase change material. At the same time, the application potential of a new ultra-thin soaking plate based on wetting grid design in local hot spot heat dissipation of the module is verified. Through the experimental test, Under 5C high-rate discharge, the system held the maximum module temperature at 48.1˚C, 24.45˚C and 14.5˚C lower than the natural-convection module (72.55˚C) and the pure-PCM module (62.6˚C) respectively, with the in-module temperature difference kept around 3˚C, below the 5˚C uniformity target. In addition, it is found that the thermal resistance of the ultra-thin soaking plate with 65 μm wetting grid pattern is reduced to 0.058˚C/W at the optimal liquid injection rate of 61.6%, which can well realize the component-level scheme of local hot spot management of high power density battery module.