车用锂离子动力电池系统的安全性

On the safety issues of lithium ion battery

动力电池安全性是新能源汽车大规模推广应用过程中,各方最关注的焦点问题之一。本文阐述锂离子动力电池作为车用电源系统的安全性问题及其有效的解决方案。动力电池系统安全性问题主要分为3个层次,即"演变"、"触发"和"扩展"。"演变"是指动力电池安全性事故发生之前,故障可能经历了长期的演化过程;"触发"是"演变"过程的转折点,也可以是突发情况破坏了动力电池系统,并导致安全性事故。阐述了锂离子动力电池热失控"触发"的机理,对于不同种类的热失控触发形式进行了分析。在动力电池安全性事故"触发"问题上,最为核心的问题是锂离子动力电池的热失控。热失控"触发"发生后,应防止热失控"扩展"的发生。论述了热失控"扩展"过程的机理,以便于提出更加合理的安全性设计方案,防范热失控"扩展"的发生,降低安全性事故造成的损害程度。基于热失控"演变"、"触发"与"扩展"的机理,提出了事故防范和安全性监控的多项措施。

The safety of lithium ion battery power system should be enhanced before the massive application of electric vehicles. The safety problem needs to be fully combed in order to improve the safety of the vehicle power battery system. This paper attempts to interpret the safety problem of lithium ion power battery system and to find further solutions. The safety of power battery system is divided into three levels in this paper, namely, ＂evolution＂, ＂trigger＂ and ＂propagation＂. The ＂evolution＂ refers to that the failure may be experienced a long evolutionary process before the battery safety accident occurs. The ＂trigger＂ is the turning point of the ＂evolution＂, and can also be unexpected events that destroy the power battery system upon vehicle accidents. The thermal runaway mechanism of lithium ion power battery is expounded, and different triggering ways of thermal runaway are analyzed. On the issue of the ＂trigger＂ of the safety accident of the power battery, the most critical point is the thermal runaway. Its ＂propagation＂ should be prevented when thermal runaway ＂trigger＂ occurs. Understanding more about the thermal runaway ＇!propagation＂ mechanism can help designers to optimize safety design, prevent thermal runaway ＂propagation＂, and reduce the degree of damage caused by safety incidents. Based on the discussion on the ＂evolution＂, ＂trigger＂ and ＂propagation＂, this paper puts forward a number of measures for accident prevention and safety monitoring.