【作者】 刘平；

【导师】 潘仁明；

【作者基本信息】 南京理工大学 ， 安全工程（专业学位）， 2021， 硕士

【摘要】 锂离子电池因具有能量密度大、使用寿命长、无环境污染等优点而被广泛应用。由于单粒电池储能有限,一般将多粒电池模组通过串联或并联的方式组成电池模组以满足高能量的需求,但当电池模组中的某粒或多粒电池发生热失控时会影响周围电池,甚至引发电池模组热失控。本文对过充滥用条件下锂离子电池热失控以及蔓延规律进行研究。首先详细分析了锂离子电池热失控机制,设计并搭建了用于锂离子电池模组热失控蔓延规律研究的实验系统,依托该系统,实验探索了主发电池热失控引发电池模组失控的蔓延规律,以此为基础重点研究了抑制电池组热失控蔓延方法,为电池模组的结构设计和热失控阻断技术提供依据。研究取得的主要结果与结论如下:(1)设计并搭建锂离子电池模组热失控蔓延规律实验系统,通过实验验证了该系统的可行性。(2)在隔热环境中研究了主发电池与被发电池的相对数量、被发电池荷电状态以及主发电池与被发电池间距对被发电池热失控蔓延规律的影响。研究发现:增加主发与被发电池的相对数量或被发电池荷电状态会促进电池热失控蔓延的发生,而增加主发与被发电池间间距能减弱失控主发电池对被发电池的传热强度,对锂离子电池热失控蔓延有阻碍作用,间距足量时可避免被发电池失控。因此可以得出,被发电池首先须含足够电量,而且能在主发电池失控时获取足够热量和热流强度时才会发生热失控。(3)通过在主发电池与被发电池之间设置气凝胶隔热片和气凝胶隔热片包裹被发电池的两种隔热方式,从而提高了主发电池与被发电池之间的热阻。研究发现:当主发电池与被发电池之间存在热阻时能有效阻断被发电池的热失控蔓延,其中包裹被发电池隔热方式削弱了电池散热效率,热量易于聚集,仍有可能导致被发电池发生热失控,由此可见加载独立隔热片,是一种较为有效的电池模组热失控蔓延的阻断方法。(4)使用水、水成膜泡沫灭火剂和全氟己酮灭火剂对单粒过充热失控主发电池和热失控电池模组分别进行了热失控抑制实验。实验结果表明,三种灭火剂均可有效降低被发电池温度上升速率,成功抑制被发电池的热失控蔓延,其中以全氟己酮灭火剂抑制电池热失控效果最好。此外在电池发生热失控之前,若电池箱内的环境中含有足量灭火剂,电池组的热失控蔓延有望可以被避免的。更多还原

【Abstract】 Lithium-ion batteries are widely used because of their high energy density,long service life and no environmental pollution.Due to the limited energy storage of a single cell,multi-cell battery modules are composed of series or parallel connection to meet the demand of high energy.However,when one or more batteries in the cell module lose thermal control,it will affect the surrounding cells,and even cause thermal loss of control of the cell module.In this paper,the thermal runaway and spread law of lithium-ion battery under overcharge and abuse conditions were studied.First of all,the thermal out-of-control mechanism of lithium-ion battery is analyzed in detail,and the experimental system was designed and built for the study of thermal runaway spread law of lithium-ion battery module.,relying on this system,the spread law of thermal runaway caused by thermal runaway of the master battery was explored experimentally.On this basis,the method of restraining thermal runaway spread of battery pack was studied,which provided reference for structural design and thermal runaway control of battery module It can provide the basis for the control and blocking technology.The main findings and conclusions of the study are as follows:(1)The experimental system of thermal runaway propagation law of lithium-ion battery module is designed and built,and the feasibility of the system is verified by experiments.(2)The effects of the relative number of the master battery and the delivered battery,the state of charge of the delivered battery and the distance between the master battery and the delivered battery on the thermal runaway propagation of the delivered battery were studied in the thermal insulation environment.The results show that: increasing the relative number of the master battery and the delivered battery or the state of charge of the delivered battery can promote the occurrence of thermal runaway spread of the battery,and increasing the distance between the master battery and the delivered battery can weaken the heat transfer intensity of the master battery to the delivered battery,and hinder the thermal runaway spread of the lithium-ion battery.When the distance is sufficient,the runaway spread of the delivered battery can be avoided.Therefore,it can be concluded that the delivered battery must first contain enough electricity,and can obtain enough heat and heat flux when the main generator battery is out of control.(3)By installing the aerogel insulation sheet and the aerogel insulation sheet between the master battery and the delivered battery,the two heat insulation modes of the battery are wrapped,thereby enhancing the thermal resistance between the master battery and the delivered battery.The results show that: when there is thermal resistance between the master battery and the delivered battery,it can effectively block the thermal runaway spread of the master battery,in which the heat insulation method of wrapping the master battery weakens the heat dissipation efficiency of the battery,and the heat is easy to accumulate,which may still cause the thermal runaway spread of the delivered battery.Therefore,loading the independent heat insulation sheet is a more effective way to block the thermal runaway spread of the battery module Law.(4)Using water,water film foam extinguishing agent and Perfluorocarbons extinguishing agent to control the thermal runaway of a single grain overheated main runaway battery and a heat runaway battery module respectively.The experimental results show that the three kinds of fire extinguishing agents can effectively reduce the temperature rising rate of the battery,and successfully inhibit the thermal runaway spread of the battery,among which Perfluorocarbons fire extinguishing agent has the best effect.In addition,before the thermal runaway of the battery,if the environment in the battery box contains enough fire extinguishing agent,the thermal runaway spread of the battery pack is expected to be avoided.更多还原