Experimental Studies on the Thermal Runaway of Three Lithium-Ion Batteries Used in Unmanned Aerial Vehicles

Abstract

With the glorious progress and applications in the field of unmanned aerial vehicles and low-altitude economy, the safe use of lithium-ion batteries in daily life has become indispensable and pivotal. It is unfortunate that there has not been any evaluation of the risk of LIBs being exposed to thermal abuse in unmanned aerial vehicles. The topic of thermal runaway of LIB used in unmanned aerial vehicles is not well-studied. Three different brands of LIBs (including Fullymax, ACE, and SEFU ones) were studied using pseudoadiabatic calorimeter. Runaway data of exothermic onset temperature (Tonset), crucial temperature (Tcr), maximum temperature (Tmax), maximum self-heat rate ((dT/dt)max), maximum pressure (Pmax) and amount of noncondensable gases (Δn) were determined among these LIBs under 25%, 50% and 100% SOCs. Thermal stability (higher Tonset), no return hazard (lower Tcr), fire hazard (higher Tmax), rate hazard (higher (dT/dt)max), and pressure hazard (higher Pmax or higher Δn) are among the thermal risk classifications. The discussion covers thermal risk that include stability, no return hazard, fire hazard, rate hazard, and pressure hazard. SEFU battery is the most unstable (with a lowest Tonset of 90.0 °C) among these three LIBs; however, the ACE is relatively stable due to its higher Tonset of 105.1 °C. Even though they have similar Pmax, the Fullymax one can be deduced to be the most dangerous with the highest Tmax (related to fire hazard) of 605.3 °C and largest (dT/dt)max (related to rate hazard) of 6720 °C min–1. All these three LIBs used in UAV possess potential risk because of their possible fire hazard (Tmax > AIT of carbonate), rate hazard ((dT/dt)max > 2730 °C min–1) and pressure hazard (Pmax> 18.1 bar) under unexpected abuses in flying tasks. Identified from the aforementioned runaway parameters, thermal risk can be generally ranked as thermal stability: ACE > Fullymax > SEFU; no return hazard: ACE > SEFU > Fullymax; fire hazard: Fullymax > ACE > SEFU; rate hazard: Fullymax > SEFU > ACE; pressure hazard: SEFU > ACE > Fullymax.