A Thermo-Kinetic Model of Thermally-Induced Failure of a Lithium Ion Battery: Development, Validation and Application

Abstract

This study outlines a general methodology to develop a thermo-kinetic model of thermally-induced failure for a lithium ion battery (LIB) using COMSOL multiphysics software and experimental data collected with the Copper Slug Battery Calorimetry (CSBC). This methodology is demonstrated by developing the model for a specific type of LIB - T-Energy ICR18650. CSBC tests were conducted on the sample LIB cells to determine the thermal transport parameters and global reaction kinetics associated with the cells’ thermal failure. The model was parameterized primarily via an iterative inverse modeling analysis of the CSBC test results. The parameters include heat capacity and density of the cell, radial thermal conductivity of the cell, and the Arrhenius parameters and heat of reaction representing the process of thermal runaway. The reaction parameters were related to the cell's state of charge using empirical functions interpolating these parameter values. The fully-parameterized thermo-kinetic model was then validated against CSBC tests that were conducted under conditions not utilized in the model parameterization process. Subsequently, this model was applied to predict the thermally-induced failure of LIB cells in a more complex scenario: cascading failure of 6 LIB cells in a “billiard rack” configuration. The simulated time of onset of thermal runaway of each sequentially failing LIB cell was found to be in a good agreement (within 9%, on average) with the corresponding experimental observations.