Effect of Charging/Discharging Rate on the Thermal Runaway Characteristics of Lithium-Ion Batteries in Low Pressure

Abstract

With the widespread application of lithium-ion batteries (LIBs), their applications and transportation in the aviation field are increasing. However, the inherent risk of LIBs and the special operating environment of the aircraft bring new challenges to the fight safety. In this paper, the thermal runaway (TR) characteristics of LIBs with different charging/discharging rates are studied under the pressure of the cruising altitude of civil aircraft (20 kPa). The results show that the increase of charging/discharging rate leads to the advance of the gas release and TR time, and the decrease of TR intensity under both 20 kPa and atmospheric pressures (95 kPa). The decrease of environmental pressure results in the advance of TR time and the decrease of TR intensity. Moreover, at 20 kPa, the TR time differences between batteries with different charging/discharging rates are bigger than that at 95 kPa. The dV/dQ and impedance results show that the loss of cathode materials and the side reactions are the main factors for the decrease of battery safety. The lower external pressure facilitates the open of the safety valve and the oxidation of electrolytes, which further enlarge the safety differences between LIBs with different charging/discharging rates.