Investigation of impact pressure during thermal runaway of lithium ion battery in a semi-closed space

The thermal runaway generated by a lithium ion battery causes fire, explosions, and gas emissions. Not only are the vented gases toxic and flammable, their ejection also raises the surrounding pressure rapidly. This study focuses on analysing the characteristics, utilization, and injury risk of impact pressure from lithium ion battery thermal runaway. Experiments are performed to test the impact pressure by a self-made device with a semi-closed space. The pressure and duration of the safety valve opening, the intense ejection stage, and the interval time between the two stages are obtained and summarized with the battery under different states of charge and external heating power. The initial pressure-rise temperature, the maximum pressure temperature, and the pressure-change rate are also revealed for the characteristic of pressure variation. The test results are compared with those of previous studies. The advantage of pressure monitoring in the thermal runaway detection is discussed in comparison with temperature monitoring. The possible overpressure injury risk of the impact pressure is analysed by Bowen curves. The findings help manufacturers and users to understand thermal runaway and its emergency response more deeply from the perspective of impact pressure.