Study on influencing factors of mine explosion-proof lithium-ion batterypower supply safety design

The potential thermal runaway risk of lithium-ion batteries and the superimposing effects they may cause pose a huge challenge to the safety design of large-scale lithium-ion battery power supplies. Therefore, in some special applications, such as explosive environments in coal mines and large-capacity lithium-ion batteries, there are still many restrictions on the use of power sources and it is difficult to popularize. According to the existing research conclusions on the thermal runaway behavior of lithium-ion batteries, under the premise of insufficient gas thermodynamics and kinetic analysis, only the traditional explosion-proof enclosure is used to protect the power supply of large-capacity lithium-ion batteries for explosion-proof. There is a potential safety hazard for the lithium battery to discharge the explosion-proof enclosure pressure. Based on the analysis of existing research work, this paper selects lithium iron phosphate batteries produced by different battery manufacturers with a capacity in the range of 72～280 A·h to conduct thermal runaway experimental research, a comprehensive analysis of the battery surface and the temperature of the released gas during the thermal runaway process of the lithium-ion battery, the gas release rate, the pressure of the released gas in the container, and the composition of the released gas are comprehensively analyzed. On this basis, according to the characteristics of gas dynamics and thermodynamics, the two factors that need to be considered in the design and manufacture of lithium-ion battery power supplies suitable for portable equipment and backup power supplies for explosive environments in coal mines are systematically explained: ①The free space inside the casing of the lithium ion battery power supply，②The treatment method for the released gas when a thermal runaway accident occurs in the internal single battery of the lithium ion battery power supply, and the necessary design basis is proposed. The results of this research are expected to provide a new important reference for the explosion protection design and safety integrity assessment of lithium-ion battery power supplies used in explosive special environments.