Abstract: In order to explore the effect of external high temperature on the thermal runaway characteristics of lithium-ion batteries with different charged states,18650 lithium- ion batteries with three charged states were heated to 80 ℃ and 100 ℃ respectively. After standing at room temperature for 24 hours, the thermal runaway was made by hot runner heating coil, and the characteristic parameters such as temperature and voltage were analyzed. The results show that at the same heat treatment temperature, the higher the charge state of lithium- ion battery, the more severe the thermal runaway phenomenon, the higher the thermal runaway temperature, the earlier the voltage drop time. In the same charged state, the thermal runaway phenomenon of lithium- ion battery heat- treated to 80 ℃ is more severe, the thermal runaway temperature is higher, but the voltage drop time is later. The experimental results can provide a theoretical basis for the safe transportation, storage and application of lithium-ion batteries.

Key words: lithium- ion battery, thermal runaway, charge state;heat treatment