ANALYSIS OF CRITICAL TEMPERATURE OF PRISMATIC BATTERY THERMAL RUNAWAY INDUCED BY NAIL PENETRATION

Abstract

The temperature at which thermal runaway occurs in a battery, or the critical temperature of thermal runaway, is of great research significance. Studies show that the critical temperature for thermal runaway is not constant even for comparable batteries. Especially in penetration experiment, the critical temperature has considerable uncertainty. This study uses COMSOL to perform a penetration simulation of a large sized LFP prismatic battery, and introduces as well contact resistance. In the research, the 3D internal short circuit model and the numerical model of the side reactions are used to establish a connection between parameters that were considered almost incoherent. By changing the input of the contact resistance, the corresponding thermal runaway critical conditions are solved, thereby the relationship between the contact resistance and the critical temperature is obtained. Simulations show that there is a strong linear relationship between the critical temperature and the contact resistance. The change of short-circuit heat release power caused by the change of contact resistance will greatly affect the development process of thermal runaway. Furthermore, by utilizing the relationship derived in this thesis and integrating multiple disordered variables, the uncertainty study in penetration experiments will be simplified to a certain extent.