Modeling Cell Venting and Gas-Phase Reactions in 18650 Lithium Ion Batteries During Thermal Runaway

Jinyong Kim, Anudeep Mallarapu, Donal Finegan, Shriram Santhanagopalan

Research output: Contribution to journalArticlepeer-review

89 Scopus Citations


A numerical model is developed to study cell venting, internal pressure, and gas-phase dynamics behavior of 18650 Li-ion cells undergoing thermal runaway. A k-ϵ Reynolds-Averaged Navier-Stokes (RANS) model is adopted to describe the turbulent flow out of the cells, while the fluid dynamics inside the cells is described by Darcy-Forchheimer's equation. Thermal abuse reactions and gas generation kinetics are described by a single-step lumped reaction model. Then, a series of computational fluid dynamics (CFD) simulations are conducted on a single 18650 cell at various states-of-charge (100%, 50%, 25%) to study detailed flow and thermal behavior as a function of quantity of gas generated during cell venting. Venting events are categorized into two stages: i) breaching of the cell container and ii) thermal runaway reactions. It is found that the cell response is dominated by the second stage since most of the gases are generated during thermal runaway. Also, the propensity for propagation is highly affected by state-of-charge (SOC). Cells at higher SOCs produce more heat and gas during the venting event, owing to higher mass and concentrations of reacting gases, and consequently reach higher internal cell pressures which increase the risk of side-wall breaching.

Original languageAmerican English
Article numberArticle No. 229496
Number of pages16
JournalJournal of Power Sources
StatePublished - 31 Mar 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.

NREL Publication Number

  • NREL/JA-5700-78814


  • Battery modeling and simulations
  • Battery safety
  • Cell venting
  • Computational fluid dynamics simulations
  • Thermal runaway propagation
  • Turbulent flow battery models


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