摘要
相较于传统储能器件,锂离子电池具备高能量密度、长循环寿命、无记忆效应等优点,已被广泛应用于便携电子设备、电动汽车以及大规模储能等领域中.然而,随着锂离子电池能量密度的不断提升,其安全性受到极大挑战,电池安全事故频发.热失控是导致电池安全性不佳的主要诱因,其受到滥用情况、电池初始状态、工作条件以及电池结构设计的影响,无法完全避免.了解锂离子电池热失控的内在机制和外部特征,对电池热失控进行检测和早期预警,避免热失控引发的灾难性安全事故发生,可显著提升电池安全性.本文系统介绍了锂离子电池热失控的主要诱因(包括电滥用、热滥用、机械滥用等)、热失控发生的过程及早期预警信号和方法(包括电池电压/电阻、温度、压力、气体、声音、烟雾、火焰等).最后,对未来锂离子电池热失控预警的高精度、宽应用范围的发展趋势进行分析和展望.
Abstract
With the increasing depletion of fossil fuels(coal,oil,natural gas,etc.)and the urgent need to achieve the goals of"carbon peak"and"carbon neutral",the development of clean and sustainable energy sources(such as solar,wind,hydrogen energy and so on)as a potential alternative to the fossil fuels is imperative.However,the clean energies are volatile and intermittent and require energy storage technologies to regulate supply and demand before they can be used in real life and practical production.Lithium ion batteries,with their high energy density,long cycling lifetime,and no memory effect,are considered as a key technology for energy conversion and storage.In recent decades,lithium ion batteries have been widely used in portable electric devices,electric vehicles and large-scale energy storage.Although the energy and power densities have been continuously improved,and application scenarios are expanding,the safety issues of lithium ion batteries are becoming increasingly prominent and seriously threaten the development of lithium ion batteries.Once lithium ion batteries operate outside their preset operating windows(e.g.,temperature,voltage,current density,etc.),it can reduce the discharge capacity,shorten cycling lifetime and cause thermal runaway,resulting in fire,combustion and even explosion hazards.Therefore,it is necessary and urgent to understand the intrinsic failure mechanism and external characteristics,and to prevent safety accidents caused by the thermal runaway of lithium ion batteries,so that we can eventually produce safer lithium ion batteries with higher energy density.Currently,the main strategies to protect lithium ion batteries from the thermal runaway and improve the safety of lithium ion batteries are as follows:(1)Designing the thermal management system to ensure lithium ion batteries work stably within an appropriate operating window.For example,designing liquid cooling,gas cooling or phase transition(liquid gas)cooling system in the thermal management system to enable the battery to operate within the ideal temperature range(20±5 to 60±5℃).(2)Improving key materials and structures of lithium ion batteries to enhance the stability and reduce the risk of the thermal runaway of lithium ion batteries,such as addition of electrolyte additives,design and optimization of functional separators and their preparation process,structural engineering of cathode,anode and solid electrolyte materials.(3)Based on the changes in current,voltage,resistance,pressure,and gas generation phenomena during the thermal runaway of lithium ion batteries,developing real-time monitoring system to provide early warning and intervention.(4)From the perspective of heat release and combustion caused by the thermal runaway,developing efficient flame retardant or fire-extinguishing agents for the fire protection systems.Among them,early monitoring and warning for the thermal runaway is an effective means to improve the reliability and safety of lithium ion batteries.This article presents a systematic review of the causes,processes and methods of prediction and early warning of the thermal runaway of lithium ion batteries.Firstly,the most common abuse behaviors and corresponding mechanisms related to the thermal runaway of lithium ion batteries are summarized.Secondly,the main stages of the thermal runaway process of lithium ion batteries,including the early reaction stage,the bulging stage and the fire/explosion stage,are discussed in detail.Subsequently,the signals in the above three stages,including voltage,resistance,temperature,pressure,gas,sound,smoke,fire,etc.,and the early-warning technologies based on them are discussed in detail.Finally,prospective for future thermal runaway early-warning technologies of lithium ion batteries with high accuracy and wide application range is proposed.This review aims to achieve a broader and deeper understanding both in intrinsic mechanisms and external characteristics of the thermal runaway behaviors,and provide guidance on the development of highly effective early-warning technologies of lithium ion batteries.
基金项目
南方电网数字电网研究院有限公司储能电池安全智能监测传感与预警系统研究项目(670000KK52220024)
国家重点研发计划(2021YFB2401900)
NETL
NSTL
维普
万方数据