锂离子电池热失控防范技术

Thermal runaway-preventing technologies for lithium-ion batteries

安全性是制约高比能、大容量锂离子电池规模应用的重要技术问题,热失控是导致电池发生爆炸、燃烧等不安全行为的根本原因。从电化学角度来看,在锂离子电池内部建立一种自激发热保护机制,切断危险温度下电池内部的离子或电子传输,关闭电池反应,是解决这一问题的有效途径。基于这一考虑,近年来人们提出了一系列新型热失控防范技术,包括正温度系数电极(即PTC电极)、热敏性微球修饰隔膜(或电极)、热聚合添加剂等。本文在简要介绍这些安全性技术的实现方式和工作原理之后,重点介绍了这一领域的最新研究进展。在此基础上,从实际应用需求出发,对其存在的问题及发展趋势进行了探讨。

Safety concern imposes an uncertainty for the large-scale applications of high energy density and high capacity lithium-ion batteries(LIBs)in electrical vehicles and electric storage devices.Thermal runaway is recognized to be the main cause for the unsafe behaviors,such as firing and explosion.From the electrochemical point of view,an effective way for resolving this problem is to build a thermal shutdown mechanism in the internal LIBs to switch off the ions or electrons transport at risky temperatures,thus terminating the battery reactions and preventing the thermal runaway from happening.Based on this consideration,various thermal runaway-preventing technologies have been proposed for improving the safety of LIBs in recent years,such as positive-temperature-coefficient electrode(i.e.PTC electrode),thermoresponsive microsphere-coated separator or electrode,thermally polymerizable additives,and so on.This paper intends to review the recent progress of these technologies after a brief introduction to their implementation approaches and working mechanisms.Furthermore,the problems and future development orientations in this area have also been discussed from a viewpoint of practical application demand.