Influence of longitudinal wind on thermal runaway and fire behaviors of 18650 lithium-ion batteries in a restricted channel

Thermal runaway (TR) is an essential issue puzzling the application of lithium-ion batteries, while there is a knowledge gap about TR characteristics of batteries under varied wind velocities. This study employed an experimental approach to investigate the influence of longitudinal wind velocity on TR behaviors of batteries in a restricted channel. The results indicate that the key parameters of TR are significantly affected by wind veloc-ities. The onset time of safety valve opening, TR occurring, and maximum surface temperature appearing rises exponentially over wind velocity. Whereas the onset temperature of the first two decreases linearly with wind velocity. Temperature rising rates at different stages also tend to change similarly. The maximum surface tem-perature and temperature rise rate have no visible correlation with wind velocity. A simplified thermal balance analysis method was proposed to dissect the wind velocity effect during TR. Three regions for TR can be divided based on the critical wind velocity of 3.5 m/s and 4.5 m/s. The maximum temperature difference in the channel corresponds to the flow state depending on wind velocity. This work can enhance our knowledge of the longi-tudinal wind impact on TR and provide a new viewpoint to preventing TR and its propagation.