车用电池模组热蔓延防护结构的数值仿真研究

Numerical simulation study on thermal runaway propagation mitigation structure of automotive battery module

本文通过数值仿真研究了一种抑制方形电池模组热失控蔓延的防护结构。针对车用50 A·h方形三元锂离子电池,基于锂离子电池电极材料与电解液副反应机理建立单体电池热失控模型。通过与已有研究结果进行对比验证,表明所建立的热失控模型具有较高的精度。基于验证后的单体电池热失控模型,建立了加装导热套筒的电池模组热防护结构。导热套筒底部与微流道冷板连接进行散热,电池之间填充隔热材料,用于阻隔由于电池热失控而导致热量向相邻电池蔓延。研究表明,与无导热套筒配置相比,所提出的方形电池模组热防护结构可以有效阻断电池模组的热蔓延。基于所提出的方形电池模组热防护结构,分析了电池之间绝缘层热阻、导热套筒高度以及导热板高度等因素对相邻电池热蔓延的影响。研究表明:绝缘层热阻达到0.03 m^(2)·K/W以上,相邻电池才不发生热失控。同时考虑到轻量化设计因素,选取导热套筒高度不应高于10 mm以及导热板高度在60~65 mm之间,可用于防护电池模组热蔓延。本文所提出的热防护结构和参数研究为电池包热安全设计提供了参考依据。

In this paper,a structure for preventing the thermal spread of prismatic cells is studied via numerical simulation.The thermal runaway model was established for 50 A·h prismatic ternary lithium-ion batteries used in vehicles based on the thermal runaway side reaction mechanism in the electrodes and electrolyte.The model is verified by comparing it to existing research to demonstrate that the established thermal runaway model has high accuracy.Based on the verified single battery thermal runaway model,a battery module thermal protection structure was established in which each battery cell was assembled with a thermal sleeve.The bottom of the thermal sleeve was connected with a minichannel cold plate for heat dissipation.Insulation materials were filled between batteries to prevent heat from spreading to adjacent batteries due to thermal loss.The results show that the proposed thermal protection structure can effectively block the thermal spread of the battery module compared with the configuration without a thermal sleeve.Moreover,the influence of the thermal resistance of the insulation layer,the height of the thermal sleeve,and the height of the thermally conductive plate on the thermal spread of adjacent batteries was analyzed based on the proposed thermal protection structure.The research shows that the thermal resistance of the insulation layer is above 0.03 m^(2)·K/W,and the adjacent#2 battery does not have thermal runaway.In addition,the height of the thermal sleeve should not be higher than10 mm considering the impact of actual engineering system quality factors,and the height of the thermally conductive plate should be between 60 and 65 mm,which can be used to prevent the thermal spread of the battery module.The thermal protection structure and parameters presented in this paper provide a reference for the thermal safety design of battery packs.