2021 Fiscal Year Annual Research Report
Clarification and model development for the flame extinction mechanism of battery electrolytes using a wick combustion method
| Project/Area Number |
20K22377
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| Research Institution | Hokkaido University |
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Principal Investigator |
GUO FENG 北海道大学, 工学研究院, 学術研究員 (40886206)
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| Project Period (FY) |
2020-09-11 – 2022-03-31
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| 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 |
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| Outline of Annual Research Achievements |
The wick-LOC method was developed in this research to quantify the flammability of liquid fuel, especially for electrolytes used in lithium-ion batteries (LIB). After the experimental work, the flame extinction mechanism was investigated in detail using the numerical approach in the final fiscal year. With a series of parametric studies on mesh resolution, time step, reaction mechanism, and ignition method, the optimized operation conditions were determined. Associated with the temperature measurement, the temperature boundary on the wick surface was confirmed as constant (at the boiling point of fuel) under the full flame mode. In addition to the 1-step reaction model, the 2-step, quasi-global and detailed reaction mechanisms were employed in the 2-D CFD model. As the baseline, the simulation results of ethanol wick flame employing the 2-step reaction mechanism showed a good agreement with experimental findings. Under the investigation of the structure of near-limit edge flame, it was found that the reaction rate in the fuel-lean condition dominates the blowoff of the wick flame compared with the stoichiometric condition. When the edge flame stabilization theory was applied for the wick flame, the laminar flame speed of the fuel-lean condition would be adopted for correction.
Combining experimental and numerical work, the wick-LOC method could be a simple way to examine the combustion reaction parameters of liquid fuels. Furtherer, simplified reaction mechanisms of new fuels like LIB electrolytes would be estimated reversely for the safety design of LIB.
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