Experimental evaluation of the influence of excessive electric current on the fire hazard of lithium-ion power cell

Abstract

Panasonic NCR18650B (LiNi0.8Co0.15Al0.05O2) lithium-ion power cell (LIPC) and its performance after exposure to excess direct current are considered in this paper. The basic fire hazard indicators (element ignition temperature, flame temperature, element heating time, etc.) were experimentally established and mathematically confirmed for the examined LIPC. According to the results of experimental studies, the time of occurrence of an irreversible thermochemical reaction in a lithium-ion power cell was determined depending on the different DC current strengths. Additionally, the critical temperature of the onset of an irreversible thermochemical reaction and the total combustion temperature of the element have been established. The application of the Joule-Lenz and Fourier laws allowed for a mathematical notation of the dependence (influence) of DC strength over time and the heating of the element to a critical temperature. The heating time of Panasonic NCR18650B LIPC (LiNi0.8Co0.15Al0.05O2) to a critical temperature of 100–150 °C under the influence of excess current was experimentally established and mathematically confirmed. The determined critical indicators of the element (temperature, time, etc.) make it possible to further devise a number of necessary regulatory documents that will allow them to be certified, tested, and, in general, to better understand the dangers that they may pose. A mathematical model was built, which, taking into account the geometrical parameters of the element, makes it possible to calculate the onset of the critical temperature of such elements with excellent geometric parameters without conducting experimental studies