A novel method to determine the multi-phase ejection parameters of high-density battery thermal runaway

The growing demands on high-performance energy systems for emerging technologies drive the advancement of high-density batteries. However, the issue of thermal runaway (TR), particularly in high-density battery, remains a major challenge worldwide. One of the primary hazards associated with TR is the emission of combustible ejections. Therefore, elucidating the TR ejection parameters holds significant meaning. In this study, we propose a novel method to determine the ejection parameters. Based on the principles of momentum conservation, the proposed method is applicable to high-density battery types. For the 52 A h ternary battery, our results indicate the following: 1) the ejection velocity reaches a peak of 210 m/s, a maximum mass loss rate of 0.041 kg/s and a maximum total pressure of 112.325 kPa; 2) the temperature of the particles is 200 °C higher than that of the gas. Furthermore, we have derived empirical formulas that encompass the ejection dynamics, thereby facilitating the modeling of TR degassing and ventilation within a battery pack. This approach overcomes the challenges associated with measuring the ejection parameters in high-density battery TR, such as the extreme temperature, flammability, and multiphase composition. Consequently, this method exhibits great potential to bolster the fire safety and structural design of battery packs.