Health & Environmental Research Online (HERO)


Print Feedback Export to File
8611799 
Journal Article 
Overcharge investigation of large format lithium-ion pouch cells with Li(Ni0.6Co0.2Mn0.2)O-2 cathode for electric vehicles: Thermal runaway features and safety management method 
Zhu, XQ; Wang, ZP; Wang, YT; Wang, H; Wang, C; Tong, L; Yi, M 
2019 
Yes 
Energy
ISSN: 0360-5442 
169 
868-880 
English 
WOS:000459528500071 
In this paper, the overcharge-induced thermal runaway features of large format commercial lithium-ion batteries with Li(Ni0.6Co0.2Mn0.2)O-2 (NCM622) cathode for electric vehicles under different current rates (C-rates) have been systematically studied at ambient temperature. The overcharge process is characterized as four stages. The temperature rise and the maximum temperature of the battery surface don't increase in proportion to the applied C-rates. However, with the increase of C-rates, the crest voltage of voltage curve rises linearly. When the voltage reaches approximately 5.1 V, a new voltage plateau appears in the cases below 2C. It is not sufficient that the temperature sensor is placed only near the terminal tab for most battery packs of EVs. In addition, the accumulated heat analysis demonstrates that side reactions dominate the temperature rise and contribute to most of the accumulated heat before thermal runaway. To mitigate the impact of overcharge and avoid the thermal runaway risk, a safety management method is proposed. Furthermore, the sharp drop in voltage before thermal runaway also provides a feasible approach to forewarn the users of the impending risk. These results are important for building safer batteries and providing information for the safety monitoring function of the battery management system (BMS). (C) 2018 Elsevier Ltd. All rights reserved. 
Lithium-ion battery safety; Li(Ni0.6Co0.2Mn0.2)O-2 cathode; Overcharge; Thermal runaway; Safety management method; failure-mechanism; realistic model; batteries; behavior; temperature; performance; simulation; deposition; Thermodynamics; Energy & Fuels