Elucidation of the impact of experimental setup on thermal runaway characterization and risk assessment of Li-ion batteries

Abstract Lithium-ion batteries play an essential role in various applications, from portable consumer electronics to electric vehicles and energy storage systems but their safety remains a major concern for manufacturers and users. Understanding the thermal runaway (TR) phenomenon and the factors that influence it has therefore received considerable scientific attention. This study focuses on the impact of the experimental setup on the TR parameters. To investigate this, the TR behavior of an NMC 811 cell was tested in two setups with different volumes under two environmental conditions: air and vacuum that represent two extreme conditions for a closed calorimeter. In each case, the same methodology was applied, by heating the cell at 6 °C min −1 , and the measured and calculated parameters were compared between setups. Understanding the effects of the experimental device under different environmental conditions is essential to draw clear conclusions about the potential risks of Li-ion cells. Results show that both configurations give similar trend in the evolution of TR time, cell temperature at venting and TR, and the amount of gas ejected. The mass loss is affected by the setup. The composition of the ejected gases depends on the setup and cell environment. The TR energies measured in the large volume under vacuum were comparable to those in the small volume under air/vacuum, probably due to limited quantity of oxygen in both cases. This study provides a new perspective into TR behavior of Li-ion cell by exploring the impact of the setup and its environment.