This paper reports thermal (burner) and mechanical (blunt trauma and nail penetration) abuse experiments on electric vehicle lithium ion modules comprising eight 56.3 Ah lithium nickel manganese cobalt (NMC) pouch cells. The aim of project part of which is described in this paper was to study the problem of thermal runaway in lithium ion batteries under different abuse conditions and at different SOC and to bridge the current gap in the literature between cell level studies and research at pack and system level. These experiments were part of an ongoing research programme leading up to studies at pack and system level. The responses of the cells to the various forms of abuse were monitored with optical and thermal cameras, thermocouples and by measuring cell voltage. Draeger gas sensors were also employed where possible. The nail penetration experiments were carried out at (nominally) 96.5%, 75% and 50% SOC, and at 96.5% SOC as a function of penetration location: the experiments strongly suggest that low SOC is as hazardous as high SOC, in contrast to a general perception in the literature, as the likely hazards are simply different and include the possibility of violent vapour cloud explosion. Thus, in all experiments, the first obvious indication of thermal runaway was the ejection of white vapour: if this ignited, the obvious hazard was that of fire. If, however, the vapour did not ignite, it posed an entirely different hazard in terms of high toxicity and the potential for a violent vapour cloud explosion: this is the first mention of such a phenomenon linked to lithium ion batteries in the academic literature. The experiments showed that cell voltage cannot be employed as a reliable warning of thermal runaway. Finally, the data obtained support a wholly novel theory, yet to be adopted across the community, in which thermal runaway can involve the direct solid-state electrochemical reaction between anode and cathode at temperatures ≥250 ˚C following venting of the electrolyte.

本文报道了在电动汽车锂离子模块上的热（燃烧器）和机械（钝性创伤和指甲渗透）滥用实验，这些模块包含八个56.3 Ah锂镍锰钴（NMC）袋式电池。本文描述的项目部分的目的是研究在不同滥用条件下和不同SOC下锂离子电池的热失控问题，并弥合目前电池水平研究与电池组研究之间的差距。系统级别。这些实验是正在进行的研究计划的一部分，该计划导致在包装和系统级别进行研究。用光学和热像仪，热电偶并通过测量电池电压来监控电池对各种形式滥用的反应。尽可能使用Draeger气体传感器。钉穿透实验是在（名义上）SOC为96.5％，75％和50％的情况下进行的，SOC为96.5％时作为穿透位置的函数：实验强烈表明，低SOC与高SOC一样危险。这是文献中的一种普遍看法，因为可能的危害完全不同，包括可能发生剧烈的蒸气云爆炸。因此，在所有实验中，热失控的第一个明显迹象是白蒸气的喷射：如果点燃，则明显的危险是着火。但是，如果蒸气未点燃，则在高毒性和剧烈蒸气云爆炸的可能性方面构成完全不同的危害：这是学术文献中首次提及与锂离子电池有关的这种现象。实验表明，电池电压不能用作热失控的可靠警告。最后，获得的数据支持了一个全新的理论，但尚未在整个社区中被采用，其中热失控可能涉及在电解液排放后，≥250℃的温度下阳极和阴极之间直接进行固态电化学反应。