Thermal runaway characteristics of 18650 lithium-ion batteries under the influence of inclination angles

Published

February 10, 2026

Author(s)

Jian Chen, Xue Liu, Haolan Chen, Qiuhong Wang, Jun Deng, Jingyu Zhou, Wai Cheong Tam, Yanni Zhang

Abstract

This paper experimentally examined the thermal runaway (TR) characteristics and burning behavior of 18650 lithium-ion batteries (LIBs) with different inclination angles and states of charge (SOC). A series of experiments on TR burning of LIBs was conducted, measuring and analyzing the burning behavior, surface temperature, TR initiation time, and mass loss of the batteries. It was found that during the jet flame stage, the flame's direction generally aligned with the battery's inclination. The rupture time of the safety valve and the TR initiation time occurred earlier as the inclination angle and SOC increased, indicating that the battery's inclination could facilitate thermal runaway. Additionally, the mechanisms of TR at various inclination angles were studied based on internal reaction characteristics and heat transfer within the battery. Lastly, it was observed that SOC had a greater influence on mass loss during TR than the inclination angle. This research offers valuable guidelines for understanding the TR characteristics of LIBs with different inclination angles in real fire scenarios.

Citation

Journal of Energy Storage

Pub Type

Journals

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Keywords

lithium-ion battery, inclination angle, thermal runaway, state of charge, burning behavior

Citation

Chen, J. , Liu, X. , Chen, H. , Wang, Q. , Deng, J. , Zhou, J. , Tam, W. and Zhang, Y. (2026), Thermal runaway characteristics of 18650 lithium-ion batteries under the influence of inclination angles, Journal of Energy Storage, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=961400 (Accessed March 16, 2026)