Study on the Flammability Limits of Lithium-Ion Battery Vent Gas under Different Initial Conditions

Biao Ma; Jie Liu; Ruiguang Yu

doi:10.1021/acsomega.0c03713

Study on the Flammability Limits of Lithium-Ion Battery Vent Gas under Different Initial Conditions

ACS Omega. 2020 Oct 22;5(43):28096-28107. doi: 10.1021/acsomega.0c03713. eCollection 2020 Nov 3.

Authors

Biao Ma^{1

2}, Jie Liu^{1

2}, Ruiguang Yu^{1

2}

Affiliations

¹ Department of Power Mechanical Engineering, Beijing Jiaotong University, Beijing 100044, PR China.
² Beijing Key Laboratory of New Energy Vehicle Powertrain Technology, Beijing Jiaotong University, Beijing 100044, PR China.

Abstract

In this paper, the flammability limit of the battery thermal runaway vent gas (BVG) is studied numerically by using the CHEMKIN 2.0 code. The research content mainly includes the change of flammability limit with the state of charge, initial temperature, and initial pressure. The chemical reaction kinetics at the flammability limit is also analyzed. The results show that the flammability limit obtained by numerical simulation is in good agreement with that calculated by Le Chatelier's mixing rule. The lean and rich limits increase with the increase of the initial pressure, and the increasing trend gradually slows down. As for the change of initial temperature, higher the temperature is, wider the limits are. In addition, according to the simulation results, the fitting formula of the flammability limit changing with the initial conditions is given. Furthermore, in order to reveal the important elementary reactions controlling the flammability limit, the sensitivity analysis with respect to the flame speed and heat release rate analysis of the elementary reactions are carried out at the flammability limit. Finally, the effect of CO₂ and H₂ content on the flammability limit of BVG is discussed.