Experimental and modeling analysis of jet flow and fire dynamics of 18650-type lithium-ion battery

Author: Mao, B. B., Zhao, C. P., Chen, H. D., Wang, Q. S., Sun, J. H.

Journal: Applied Energy

DOI: 10.1016/j.apenergy.2020.116054

Keywords: Lithium-ion battery safety, Thermal runaway, Gas generation, Jet flow, Fire dynamics, Flame height, thermal runaway propagation, failure-mechanism, diffusion flames, behavior

Abstract: 

The lithium-ion battery (LIB) is widely used in modern society, while the fire accidents caused by battery thermal runaway (TR) also happen frequently. However, the gas generation, jet flow, and fire dynamics of LIB TR are still unclear. In this paper, a lumped model for the characteristics of the 18650-type LIB jet flow and fire dynamics is set up and validated by experiments. The gas generation rate is described by the Arrhenius equation, and the peak generation rate is 2.724 g s-1. The isentropic flow equations are used to simulate the gas venting process. The gas flow is choked when the safety valve opens, then returns to subsonic levels until the onset of TR. When the cell falls into TR, the peak speed of the gas flow at the orifice is 162.0 m s-1, and the corresponding peak mass flow rate is 2.6 g s-1. The trend and peak value of the simulated flame height agree with the experimental results. This feasible model describes the LIB fire dynamics, and the knowledge gap over the gas generation rate and jet flow speed during TR is filled. The reveal of the fire dynamics of LIB provides guidance for the design of safety precaution measures on LIB packs in electric vehicle and energy storage system. Furthermore, the cause of error is analyzed, and some future modifications on the model of LIB fire are proposed.