Thermal runaway in lithium-ion batteries is a primary safety concern in electric vehicles (EVs). Herein, a numerical thermal abuse model is proposed that integrates ordinary differential equations (ODEs), heat-transfer partial differential equations (PDEs), natural convection in computational fluid dynamics (CFD), and thermal radiation to investigate thermal propagation in a battery pack. A three-dimensional geometric model of a high-energy lithium-ion battery pack comprising 18,650 format cells was constructed to analyze the thermal characteristics using the finite element method (FEM). A thermal abuse test was conducted to simulate the spread of thermal runaway in cells owing to multipoint heating. The maximum differences in the peak temperature between the proposed model and the model without convection were −150 K and 52.0 s, respectively, while the differences between the proposed model and the model without radiation were −52.4 K and −125.0 s, respectively. Furthermore, four additional models with different cell-to-cell gaps were constructed to study the thermal propagation characteristics, showing that the presence of a cell-to-cell gap accelerated heat transfer but compromised energy density for the battery pack. Ultimately, the coupling model at the pack level proposed in this study can improve the design of battery thermal management systems.

锂离子电池的热失控是电动汽车 (EV) 的主要安全问题。本文提出了一种数值热滥用模型，该模型集成了常微分方程 (ODE)、传热偏微分方程 (PDE)、计算流体动力学 (CFD) 中的自然对流和热辐射，以研究电池组中的热传播。构建了包含 18,650 个格式电池的高能锂离子电池组的三维几何模型，以使用有限元法 (FEM) 分析热特性。进行热滥用测试以模拟由于多点加热导致的电池中热失控的扩散。所提出的模型和没有对流的模型之间峰值温度的最大差异分别为 -150 K 和 52.0 s，而所提出的模型和没有辐射的模型之间的差异分别为-52.4 K和-125.0 s。此外，还构建了四个具有不同电池间间隙的模型来研究热传播特性，表明电池间间隙的存在加速了热传递，但损害了电池组的能量密度。最终，本研究提出的电池组级耦合模型可以改进电池热管理系统的设计。表明电池间间隙的存在加速了热传递，但损害了电池组的能量密度。最终，本研究提出的电池组级耦合模型可以改进电池热管理系统的设计。表明电池间间隙的存在加速了热传递，但损害了电池组的能量密度。最终，本研究提出的电池组级耦合模型可以改进电池热管理系统的设计。