Clarification and model development for the flame extinction mechanism of battery electrolytes using a wick combustion method

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K22377
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0301:Mechanics of materials, production engineering, design engineering, fluid engineering, thermal engineering, mechanical dynamics, robotics, aerospace engineering, marine and maritime engineering, and related fields
• Research Institution: Hokkaido University
• Principal Investigator: GUO FENG 北海道大学, 工学研究院, 学術研究員 (40886206)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Keywords: 電解液溶媒 / 灯芯燃焼 / 消炎限界 / 数値シミュレーション / 火災安全

Outline of Final Research Achievements

Electrolyte solvents used in Li-ion batteries contribute to the main fuel of the battery fire; however, the flammability of such mixed liquid fuel is not well understood. A wick combustion system combining with the Limiting Oxygen Concentration method (wick-LOC method) has been developed to evaluate the flammability and extinction limit of liquid fuels, especially for electrolyte solvents. In the recent funded years, following achievements are made: (1) The LOC of organic solvents and their mixture are determined and compared quantitatively. (2) The flame extinction mechanisms (blow-off or quenching) on the wick burner have been distinguished for different flame modes. (3) The near-limit flame oscillation has been investigated as the precursor of the flame extinction. (4) The numerical model of wick flame was established and showed a good agreement of experiments. In addition, more details of the wick flame blowoff were clarified via CFD simulation.

Free Research Field

熱工学 / 燃焼工学

Academic Significance and Societal Importance of the Research Achievements

この研究では、燃焼の基礎とLIB電解質の安全性を結びつけることを目指します。ISO規格の限界酸素指数を灯芯燃焼装置に適用することで、液体燃料の消火限界を定量化することができる。燃焼科学の分野では、消炎の観点から液体燃料の難燃メカニズムの基礎に貢献することができます。電池業界では、wick-LOC法が存在することで定量的な燃焼性評価が可能となり、より安全な電解質設計やLIBの火災抑制に有用な参考となる。