Abstract: In the context of “peak carbon dioxide emissions and carbon neutrality”, immersion liquid cooling technology is one of the lithium-ion battery thermal management technologies with good application prospects. In the new generation of thermal management systems, the thermal runaway-induced fire of lithium-ion batteries is still a major safety hazard. This paper provides a comprehensive overview of current research advances in immersion liquid-cooling technology, and multiple modes of thermal damage in lithium-ion batteries under immersion conditions are analyzed, and the research trend of thermal damage in new lithium-ion batteries is proposed. Firstly, immersion liquid cooling technology, its advantages and disadvantages, liquid cooling methods and liquid cooling medium are introduced, focusing on phase change liquid cooling technology and the physical parameters of some commonly used liquid cooling agents. Secondly, the progress and policies of immersion liquid cooling technology in recent years are sorted out. Thirdly, from the immersion conditions of lithium-ion battery aging, thermal runaway and secondary disasters and other aspects， the new lithium-ion battery thermal disaster mode is in-depth analyzed and discussed, pointing out the existing research deficiencies. And finally put forward in the future immersion liquid-cooling conditions, the new lithium-ion battery safety and protection technology research development direction. The research of this thesis will help to improve the thermal safety of lithium-ion battery packs under immersion conditions and enhance the post-disaster emergency response capability after thermal disasters.

Key words: lithium-ion battery, fire, liquid coolant, immersion liquid cooling technology, new thermal disaster mode