Investigation of Lithium‐Ion Cell Thermal Runaway Phenomenon Based on Thermal Abuse Conditions Using Experimental and Numerical Study

Thermal runaway (TR) in Lithium‐ion cells occurs when the cell temperature exceeds 130 °C, often due to excessive heat generation. Understanding the phenomenon of TR is critical for battery safety. This study experimentally investigates TR in three types of 18650 cylindrical cells of different voltages, capacities, and chemistries, such as LCO, NMC, and LFP, while subjecting them to oven heating. A key novelty of this study is the synchronized use of infrared thermography for a detailed sequence of events to cell failure, such as cell heating, vent opening, explosion, and flame propagation and a 0D MATLAB model is developed, which incorporates the venting process, and is validated against present experimental data. The results show that LCO cells trigger TR earlier than NMC, LFP cells. Cells with higher voltage or capacity reach higher maximum temperatures ( T max ), while lower voltage cells have lower T max or do not undergo TR. Additionally, the effect of different heating rates (ranging from 2 to 10 min −1 ) on TR initiation is examined. The TR trigger temperature remains constant across heating rates, while lower heating rates significantly increase the TR initiation time. These findings provide important insights into the safety characteristics of different lithium‐ion chemistries under thermal abuse conditions.