Investigation into the Fire Hazards of Lithium-Ion Batteries under Overcharging

Dongxu Ouyang,Mingyi Chen,Jian Wang,Jiahao Liu

doi:10.3390/app7121314

Abstract

Numerous lithium-ion battery (LIB) fires and explosions have raised serious concerns about the safety issued associated with LIBs; some of these incidents were mainly caused by overcharging of LIBs. Therefore, to have a better understanding of the fire hazards caused by LIB overcharging, two widely used commercial LIBs, nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP), with different cut-off voltages (4.2 V, 4.5 V, 4.8 V and 5.0 V), were tested in this work. Some parameters including the surface temperature, the flame temperature, voltage, and radiative heat flux were measured and analyzed. The results indicate that the initial discharging voltage increases with the growth of charge cut-off voltage. Moreover, the higher the cut-off voltage, the longer the discharging time to reach 2.5 V. An overcharged LIB will undergo a more violent combustion process and has lower stability than a normal one, and the increasing cut-off voltage aggravates the severity. In addition, it is also revealed that the NMC fails earlier than the LFP under the same condition. The temperatures for safety vent cracking, ignition, and thermal runaway of LIBs exhibit similar values for the same condition, which demonstrates that the LIB will fail at a certain temperature. Finally, the peak heat flux, total radiative heat flux, and total radiative heat will rise with the increase in voltage.

Highlights

With the continuation of environmental problems such as global warming, greenhouse gas emissions, and sea-level rise caused by extensive use of fossil fuels, lithium-ion battery (LIB) have been widely used as a power source for electronic devices including laptops, mobile phones, electrical vehicles (EV), and hybrid electrical vehicles (HEV) due to their high energy density, stable performance, long life, and other excellent properties [1,2,3,4,5]
A fire occurred in a BYD electric car resulting from the spontaneous combustion of the battery, and a Tesla Model S charging at a Tesla Supercharger in Norway caught fire on 1 January 2016
Discharging discharging process of LIB can be divided into three segments

Summary

Introduction

With the continuation of environmental problems such as global warming, greenhouse gas emissions, and sea-level rise caused by extensive use of fossil fuels, LIBs have been widely used as a power source for electronic devices including laptops, mobile phones, electrical vehicles (EV), and hybrid electrical vehicles (HEV) due to their high energy density, stable performance, long life, and other excellent properties [1,2,3,4,5]. Note 7 phones, which forced Samsung to recall Note 7 all over the world and lost it billions of dollars. A fire occurred in a BYD electric car resulting from the spontaneous combustion of the battery, and a Tesla Model S charging at a Tesla Supercharger in Norway caught fire on 1 January 2016. All of these incidents have raised serious concerns about the safety of LIBs. it is necessary to conduct further research on the fire hazards of LIBs so that we can use them better

Results

Discussion

Conclusion