Thermal runaway and fire behaviors of large-scale lithium ion batteries with different heating methods.

The thermal runaway and fire of batteries under different heating methods were characterized for fully charged 50 Ah LiNixCoyMn1-x-yO2/graphite batteries. The batteries were heated using cylindrical heater and electric furnace. The influence of three key parameters (heating position, area and power) was especially investigated. Thermal runaway induced by different heating methods can be divided into three stages. More sparks and gas/white smoke ejection could be observed for the battery heated with a cylindrical heater, while the battery heated with an electric furnace produced a larger explosion and more jet fire. The onset temperature of thermal runaway for the battery heated with a cylindrical heater was lower than for the battery heated with an electric furnace. Thermal runaway can be avoided by heat dissipation before temperature beyond 126.5-132.5 ℃. The heat release, CO2 production, and mass loss were found increase as the increasing heating power or heating area. In contrast, the impact of heating position on battery burning was less obvious compared with heating power and heating area. In conclusion, a battery presents a high thermal abuse hazard under the heating method with higher heating power or larger heating area, namely, the tested electric furnace conditions in this paper.