摘要
锂离子电池安全性问题的本质是电池内部发生了热失控,热量不断的累积,造成电池内部温度持续上升,其外在的表现是燃烧、爆炸等。因此,锂离子电池的安全性与比能量、使用温度和倍率性能等存在一定的矛盾。电池能量密度越高、倍率性能越快和使用环境越恶劣,其能量剧烈释放时对电池体系的影响就越大,安全问题也越突出。当前锂离子电池电解液一般由低闪点的碳酸酯、对痕量水和温度敏感的LiPF6和其它添加剂组成,本身具有高度可燃性。同时,电解液与正负极材料之间形成界面膜被认为是电池热失控的起点。因此,电解液改性是提升电池安全性的重要措施。本文分析了离子液体和氟代溶剂等溶剂对电解液安全性的提升效果,对比了多种锂盐对电解液安全性的影响,介绍了阻燃剂、过充保护剂、锂枝晶抑制剂和成膜稳定剂等电解液添加剂对锂电池安全性的改善。最后,从电池整体应用性能的角度出发,讨论了今后高安全性锂离子电池电解液的研发方向。
The essence of the safety problem of lithium-ion battery is the internal thermal runway.Inside the battery,the heat is continuously accumulated,causing the sustaining rise of temperature.Its external performances are combustion and explosion.Therefore,the safety of lithium-ion battery has certain contradictions with specific energy,operating temperature and rate performance.Higher energy density,higher rate performance and harsher operating environment are usually the causes to a more violent energy release,leading to the greater impact on the battery system and more serious safety problems.In general,the electrolyte of lithium-ion battery consists of carbonates with low flash point,lithium salt LiPF6 with high sensitivity to 1-120 and temperature,and other additives at present.Besides,the destruction of the interface film between the electrolyte and the electrode is considered to be the starting point of the battery thermal runway.Thus,electrolyte modification is a significant method to promote battery safety.In this paper,the enhancing effects of modified solvents such as ionic liquid and fluorinated solvent on the safety of electrolyte were analyzed.The positive impacts of various lithium salts on the safety of electrolyte were compared.The safety improvements by the electrolyte additives such as flame retardant,overcharge protector,lithium dendrite inhibitor and solid-electrolyte interface stabilizer were introduced.At last,from the perspective of the overall application performance of the battery,the further research and development directions of high-safety lithium-ion battery electrolyte were discussed.
作者
沈旻
蒋志敏
李南
陈慧闯
董经博
马国强
SHEN Min;JIANG Zhimin;LI Nan;CHEN Huichuang;DONG Jingbo;MA Guoqiang(Zhejiang Research Institute of Chemical Industry,Hangzhou 310023,Zhejiang,China)
出处
《储能科学与技术》
CAS
CSCD
2018年第6期1069-1081,共13页
Energy Storage Science and Technology
关键词
安全性电解液
锂离子电池
溶剂
锂盐
添加剂
safety electrolyte
lithium-ion battery
solvent
lithium salt
additive
