锂离子电池热失控扩展特征及抑制策略研究进展

Progress on thermal runaway propagation characteristics and prevention strategies of lithium-ion batteries

锂离子电池在能量密度和工作电压等关键工作性能方面具有很大的优势,广泛应用于电化学储能系统中.锂离子电池由于具有能量密度高、电解质易燃、隔膜稳定性低等特性,不可避免地出现热失控等安全问题.若局部区域电池的热失控事件不能有效控制,将导致热失控事件扩展至系统层面,造成严重安全问题.因此,在电池体系未能取得重点突破,本征安全问题不能根本解决时,锂离子电池热失控扩展的有效抑制尤为重要.本文针对锂离子电池热失控扩展问题,首先介绍了热失控触发诱因与机理;然后从电气特征和传热特征两个角度阐述了热失控扩展特征,为热失控扩展的抑制策略设计提供理论支撑;最后在介绍典型单体热失控及其扩展模型基础上,从散热与隔热、相变材料技术、兼顾常规工况的策略三方面对热失控扩展抑制策略的研究现状进行了总结,指出了进一步研究的方向和关键所在,可为锂离子电池系统安全性能的提升提供理论基础和工程应用指导.

lithium-ion batteries have been widely used in energy storage systems due to their significant advantages such as relatively high energy and power density.In order to meet the capacity and voltage requirements of the energy storage system,it is necessary to connect the battery monomer to form a module or even a battery pack through different configurations.For the battery system composed of a large number of batteries,which is a vast reservoir of energy,its safety should be considered from the perspective of the energy storage system to ensure long-term safe and reliable operation.Because of the high energy density,flammable electrolyte and low stability of the separator,batteries may get into the problem of thermal runaway.If the speed of the thermal runaway propagation cannot be well controlled in the local area,thermal runaway could propagate from one initiating battery to its neighbors and cause disastrous consequences at the system level.Therefore,when the battery system fails to make key breakthroughs and the intrinsic safety problems cannot be fundamentally solved,it is particularly important to prevent thermal runaway propagation effectively.The purpose of this review is to discuss the research progress on thermal runaway propagation characteristics and prevention strategies of lithium-ion batteries.Firstly,the abuse conditions that may lead to thermal runaway are summarized.Then the characteristics of thermal runaway propagation are clarified from the perspectives of electrical characteristic and heat transfer characteristic.To further describe the heat transfer process of thermal runaway propagation,the thermal network diagram of the battery module is established,which could provide theoretical support for the design of the prevention strategies for thermal runaway.Finally,the modeling method of battery thermal runaway is discussed,and a systematic review of prevention strategies is presented in terms of heat dissipation and insulation,phase change material technology,and the strategy taking into account the normal working conditions.For the heat dissipation and insulation strategy,it should be noted that in order to prevent thermal runaway propagation successfully,the simple heat dissipation method requires additional investment,including cost,space,power consumption,etc.While the effective heat insulation between batteries could help block the harmful heat transfer path and reduce the requirement of fast heat dissipation capacity.For the phase change material technology,the heat transfer path diagram of the battery module is established.By improving the thermal conductivity of phase change material,the generated heat of the battery in case of thermal runaway could be distributed more uniformly to the phase change material in other areas of the module.Besides,the heat transfer capacity of the system can be further improved by setting heat transfer components at the module boundary or between the phase change materials.To further optimize the thermal management performance of the battery,the strategy taking into account the normal working conditions should be considered,which can meet the dual requirements of thermal safety and temperature control through a reasonable combination of heat conduction and insulation.This review is expected to provide theoretical basis and engineering application guidance in designing the thermal management system,so as to improve the safety performance of lithium-ion battery.