Numerical simulation study on optimizing the temperature characteristics of jet fires in forced air-cooled 18650 battery modules during thermal runaway

To investigate how to effectively reduce the average temperature in the fluid domain during thermal runaway in forced-air-cooled 18650 battery modules and to reduce the heating impact of fires on forced-air-cooled battery modules. A three-dimensional thermal runaway jet model of a forced-air-cooled 18650 battery module with a designated thermal runaway cell was constructed, and based on this model, studies on the optimization of the air-cooling structure and parameters were conducted. The results indicate that when the wind speed ranges from 1.5 m/s to 4 m/s, an increase in the air-cooling module wind speed is found to promote combustion, while when the wind speed exceeds 6 m/s, an increase in wind speed enhances the cooling flow field effect, and the time required for the fluid domain to reach the highest average temperature remains consistent. The cooling effect on the fluid domain resulting from altering the number of inlets and outlets exhibits the following order: increasing both inlets and outlets > increasing only inlets > increasing only outlets. Additionally, the maximum average temperature in the fluid domain is influenced by the outer normal direction relationship between the safety valve and the outlet. The addition of baffles is demonstrated to reduce the flame coverage area, and the flame coverage area is further reduced with a decrease in the baffle angle.