摘要
动力锂离子电池(LIB)的安全问题,尤其是热失控这一频发的安全事件严重影响乘车人员的安全以及新能源汽车的推广.本工作使用C80微量量热仪准确测量了商用锂离子电池的内在产热,通过研究分析不同质量比例的负极-电解液产热及不同质量比例的正极-负极产热,明确了LIB在热失控阶段的主要反应分为负极与电解液反应放热(130~200℃),三元镍钴锰酸锂(NCM)正极释氧与负极反应放热(200~240℃)和磷酸铁锂(LFP)正极释氧与负极反应放热(240~300℃)等.通过使用去卷积数学方法对不同质量比例的负极-电解液及不同质量比例的正极-负极产热分析研究表明,在商用锂电池注液系数条件下,电解液会优先与负极反应且被全部消耗,剩余嵌锂负极会进一步与正极反应放热,且反应热与正极材料特性密切相关.残余正极物质虽然结构坍塌仍会释氧,但由于缺少与之反应的负极或电解液,热量不会再明显增加.通过对不同荷电状态(SOC)及不同类型的锂电池主材进行产热测试,能更好地指导电极材料的改性和电池组装的开发设计,从而提高LIB整体热稳定性和安全性,最终获得整包和新能源车的安全提高.
With the vigorous development and large-scale applications of the global new energy vehicles,lithium ion battery(LIB)as the key components of electric vehicles has attracted extensive attention and research.While many urgent problems such as increasing energy density of LIB to alleviate range anxiety,developing fast charging strategy to shorten the driver's waiting time and prolonging LIB cycle life are to be solved.Especially the frequent thermal runaway incidents of LIB electric vehicles seriously affect the safety of passengers and the promotion of new energy vehicles.In order to understand the com plex thermal reactions during thermal runaway occurrence,scanning calorimeter(C80 microcalorimeter)has been proposed to analyze the thermal behavior of different full cell systems,including positive electrodes,negative electrodes,separator and electrolyte of LiFePO_(4)(LFP),Li[NiCoMn]O_(2)(NCM)and LFP/NCM hybrid LIB.A deconvolution method is used to calcu-late heat generation based on specific electrode according to the deconvoluted data.Anode-electrolyte biphasic system at different state of charge(SOC),anode single-phase system,cathode-electrolyte biphasic system and LFP/NCM hybrid full cells without electrolyte are also studied to reveal detailed steps and specific heat generation during thermal runaway mecha nism.According to the analysis,thermal runaway reactions of LIB full cells are comprised by the anode-electrolyte(130~200℃),anode-NCM(200~240℃)and anode-LFP(240~300℃).Additionally,in the case of injection co-efficient of commercial LIB,electrolyte will be used up during anode-electrolyte reaction.Then the leftover Li in anode subsequently react with cathode and the remaining decomposition of cathode will stop producing heat.Although the residual positive elec trode material may still release oxygen due to structural collapse,the heat will not increase significantly due to the lack of negative electrodes or electrolytes that react with it.These results are crucial to reveal the internal mechanism of thermal reactions in LIB,providing the foundation of different battery systems applying to electric car.
作者
顾晓瑜
李进
孙千
王朝阳
Gu Xiaoyu;Li Jin;Sun Qian;Wang Chaoyang(GAC Aion New Energy Automobile Co.,Ltd.,Guangzhou 510640;School of Materials Science and Engineering,South China University of Technology,Guangzhou 510640)
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2024年第2期146-151,共6页
Acta Chimica Sinica
基金
国家自然科学基金(22275059)
广东省科技计划项目(2021A0505110001)资助。
关键词
锂离子电池
微量量热仪
产热
镍钴锰酸锂
磷酸铁锂
lithium-ion battery
microcalorimeter
heat production
Li[NiCoMn]O_(2)
LiFePO_(4)
