Experimental study on the cooling effect of fine water mist on the thermal runaway in a single lithium ion battery

Abstract

Lithium ion battery (LIB) has been widely utilized, owing to the various advantages. However, extreme thermal hazard, namely the thermal runaway (TR), can be triggered under abusive conditions, leading to the fire or even explosion hazard. Unfortunately, efficient mitigation strategy is still lack, especially for the confined spaces. In this work, the fine water mist (FWM) is introduced into the air flow, and the cooling effect has been comprehensively study. Results show that the cooling capacity can be significantly improved with FWM droplets addition. The maximum improvement reaches 29.5 %, and the local evaporation of droplets will dominate the cooling process when the FWM flow rate exceeds 0.6 mLs−1. With the increase of air speed, the cooling capacity also increases, but the retention time of droplets in the high temperature region has been significantly shortened, leading to the decreased cooling efficiency. Inhomogeneous cooling process has been revealed, and the cooling power is found to decrease with the decreasing temperature. Moreover, the FWM cooling presents basic characteristics of convection heat transfer. The average cooling coefficient shows close relationship with the droplet content. The FWM can be used to efficiently mitigate the TR hazard, which is promising for practical utilization.