Characterization on the thermal runaway of commercial 18650 lithium-ion batteries used in electric vehicle

Panasonic 18650A and 18650B lithium-ion batteries at full-charged state are conducted to run through thermal runaway by confinement tests. Exothermic features such as onset temperature (T (onset)), crucial temperature (T (cr)), maximum self-heat rate (dT/dt)(max), maximum temperature (T (max)) and maximum pressure (P (max)) are measured and assessed. Most of the maximum temperatures within the batteries under thermal runaway exceed both 800 A degrees C and auto-ignition temperature of organic carbonates to ignite the flammable vapors of the electrolytes in the air. Adiabatic temperature rise is measured to be (775 +/- 116) A degrees C which equates to the enthalpy changes of (30.9 +/- 4.6) kJ without adopting the correction of thermal inertia. Maximum self-heat rates are determined to be in the range from 17,610 to 27,594 A degrees C min(-1). Panasonic 18650A and 18650B lithium-ion batteries shall carry the calamitous characteristics under thermal runaway if they rise above the crucial temperature of (188.0 +/- 4.4) A degrees C. Averaged enthalpy change caused by thermal runaway of a Panasonic 18650 lithium-ion battery is comparable to the equivalence of heat released by 0.71 grams of gasoline under combustion.