Determination of Thermal Physical Characteristics of the Panasonic NCR18650b Lithium-Ion Power Supply Element

Abstract The purpose of the work was to determine the thermophysical characteristics of Panasonic NCR18650B (LiNi 0.8 Co 0.15 Al 0.05 O 2 ) batteries under the condition of an external heating source. Obtaining the appropriate thermophysical characteristics of lithium-ion battery (LIB) cells can be confirmed by experimental studies and mathematical calculations. Obtaining relevant results in the future makes it possible to carry out a professional assessment of the heating temperature of such LIB, the conditions of their combustion, and the spread of fire in general. According to the results of experimental studies, namely, under the condition of the action of an external source of high temperature (flame) and uniform heating of the outer walls of the LIB, its inner part is heated to an average temperature of 168 °C for 70 seconds. For comparison, the corresponding temperature in the middle of the LIB without internal filling (cathode and anode) is reached within 45 seconds. The developed mathematical model based on the differential equation of thermal conductivity in the cylindrical coordinate system and the use of the Newton-Richmann`s Law of Heat Exchange made it possible to carry out mathematical modelling of the heating process of a LIB. Further comparison of the experimental values with the mathematical model confirmed the correctness of the experiment. The obtained mathematical model based on the experimental values made it possible to obtain the corresponding numerical values of the specific heat capacity, material density, thermal conductivity coefficient and heat exchange between the surface and the near-surface layer of the Panasonic NCR18650B.