Safety studies on lithium-ion batteries by accelerating rate calorimetry

Exothermic reactions of lithium-ion cell at various state of charge have been studied by the accelerating rate calorimetry (ARCO) technique. The thermal stability of a cell is highly dependent on its state of charge. The fully discharged cell (discharged to 2.7 V) has the highest thermal stability with the onset temperature of thermal runaway of 120/spl deg/C, and the overcharged cell (charged to 4.8 V) has the least thermal stability, starting the thermal runaway reaction at 40/spl deg/C.