锂离子电池热失控是制约其安全应用的关键因素，现有研究多聚焦于单体电池，对串联模块在多物理场耦合下的热失控机理尚缺乏系统分析。本文以四节18650三元锂离子电池串联模块为研究对象，基于ANSYS仿真平台构建三维热-电耦合模型，结合四方程动力学模型，探究了内短路、过充电及过放电三种滥用条件下的热失控演化规律。通过简化电池几何结构并引入各向异性导热系数，结合Bernardi生热模型与安时积分法，建立了考虑电化学反应与热传导耦合的仿真框架。研究结果表明：内短路条件下，热失控由触发点电池通过热传导向相邻电池扩散；过充电条件下，充电倍率从3 C(10.2 A)增至7 C(23.8 A)，热失控触发时间缩短58%，且高倍率加速SEI膜分解与电解质反应，导致反应转化率更高；过放电条件下，当系统电压从2 V降至0 V时，模块最高温度降低约160℃。本研究揭示了多场耦合下串联电池模组热失控的级联机制，为电池系统安全设计与热管理策略优化提供了理论依据。

Thermal runaway of lithium-ion batteries is a key bottleneck restricting their safety applications, and most of the existing studies focus on single batteries, and there is still a lack of systematic analysis of the thermal runaway mechanism of series modules under multi-physics coupling. In this paper, a threedimensional thermal-electrical coupling model is constructed based on the ANSYS simulation platform, and the thermal runaway evolution under three abuse conditions: internal short circuit, overcharge and overdischarge is systematically explored by combining the four-equation dynamics model. By simplifying the cell geometry and introducing the anisotropic thermal conductivity, combined with the Bernardi heat generation model and the ampere-hour integration method, a simulation framework considering the coupling of electrochemical reaction and heat conduction is established. The results show that under the condition of internal short circuit, the thermal runaway is diffused from the trigger point cell to the adjacent cell through thermal conduction. Under the overcharge condition, the charging rate increased from 3 C(10.2 A) to 7 C(23.8 A), the thermal runaway trigger time was shortened by 58%, and the high rate accelerated the SEI membrane decomposition and electrolyte reaction, resulting in a faster reaction conversion rate. Under the condition of over-discharge, when the system voltage drops from 2 V to 0 V, the maximum temperature of the module decreases by about 160 ℃. This study reveals the cascading mechanism of thermal runaway of series battery modules under multi-field coupling, which provides a theoretical basis for the safety design and thermal management strategy optimization of battery systems.