电动汽车电池外部短路的热电耦合机理与安全管理方法研究

Battery safety technology is the key technology of the development of electric vehicles. The external short circuit is one of the most serious faults among the safety problems of power battery, as the main cause of the fire and explosion of the battery. This project focuses on the method of fault mechanism of battery in the external short circuit process and its safety management research with the lithium-ion power battery as the research object, described as follows. The external short circuit fault experiments of lithium ion battery in a variety of environmental temperature are investigated. The evolution of transient electric characteristics of battery in the process of external short circuit is analyzed based on the experimental results. The coupling relationship among the battery short circuit transient current, heat production and environmental temperature is clarified. with the battery heating mechanism and heat diffusion theory, model reconstruction for the external short circuit process is implemented and multi field parameter identification method for battery external short-circuit process is proposed based on particle swarm optimization algorithm. The parity mechanism is established using an external short circuit model and health battery model; fault diagnosis method of external short circuit is investigated on the basis of the prediction accuracy of the models. Theoretically, key scientific problems including the thermal power coupling mechanism and the method of model reconstruction are explored. A model based external short circuit fault diagnosis method is proposed, which provides a theoretical basis for the further improvement of the battery safety of electric vehicles.

电池安全技术是电动汽车的发展的关键技术。在动力电池的诸多安全问题中，外部短路是最严重的故障之一，是电池起火、爆炸的主要诱因。本项目以锂离子动力电池为研究对象，重点针对电池在外部短路过程中的故障机理及其安全管理方法展开研究，包括：在多种环境温度下进行锂离子电池外部短路故障实验研究，基于实验结果解析外部短路过程中的电池瞬态电特征的演变规律；阐明短路过程中电池的瞬态电流、产热量与环境温度之间的耦合关系；结合电池产热机理和热扩散理论，进行电池外部短路过程的模型重构并基于粒子群优化算法进行多领域参数辨识方法研究；建立一种外部短路模型与健康电池模型的并行机制，以模型预测精度的变化为依据，对外部短路的故障诊断方法进行研究。拟从理论上探究电池外部短路过程中的热电耦合机理和模型重构方法等关键科学问题。提出一种基于模型的外部短路故障诊断方法，为进一步提高我国电动汽车电池安全性提供理论基础。

项目以锂离子动力电池为研究对象，针对动力电池外部短路故障展开研究，探究电池外部短路过程中的热电耦合机理和模型重构方法等关键科学问题。项目首先开展了多种环境温度下的锂离子电池外部短路故障实验研究，进而基于实验结果解析外部短路过程中的电池瞬态电特征的演变规律；阐明短路过程中电池的瞬态电流、产热量与环境温度之间的耦合关系；结合电池产热和热扩散理论，进行电池外部短路过程的模型重构，基于粒子群优化算法进行多领域参数辨识方法研究；基于所构建的重构模型建立一种基于多模型并行机制的故障诊断方法。通过研究发现了电池短路时的电气特征变化可以分为三个阶段，即：极化期、平台期和截止期，极化期以大电流极化为主要表征、阻抗迅速增大但电池无明显损坏；平台期温度迅速上升并呈现出强烈的热电耦合特性；截止期温度达到临界点、内部隔膜融合闭孔、电流截止。分析了各阶段的热电耦合特性并结合SEM扫描揭示了电池的损伤机理，率先发现了电池故障时存在两种产热模式，提出了基于随机森林算法与支持向量机的模式甄别方法，建立了电源系统故障状态的温升预测与安全管理机制，实现了车辆运行过程中的电源短路故障的快速诊断、定位及故障温升程度预测。项目研究成果已撰写3篇SCI论文并发表在国际顶级期刊上，单篇最高影响因子8.426，授权发明专利2项，获沈阳市自然科学成果奖2项，并培养了硕士研究生5名。项目的研究成果为进一步提高我国电动汽车电池安全性提供理论基础和详尽的实验数据，在车用电源领域，尤其是电池制备、安全管理领域，具有重要的科学意义和应用价值。