Self-reactive rating of thermal runaway hazards on 18650 lithium-ion batteries

Abstract

Vent sizing package 2 (VSP2) was used to measure the thermal hazard and runaway characteristics of 18650 lithium-ion batteries, which were manufactured by Sanyo Electric Co., Ltd. Runaway reaction behaviors of these batteries were obtained: 50% state of charge (SOC), and 100% SOC. The tests evaluated the thermal hazard characteristics, such as initial exothermic temperature (T ₀), self-heating rate (dT dt ⁻¹), pressure-rise rate (dP dt ⁻¹), pressure temperature profiles, maximum temperature, and pressure which were observed by adiabatic calorimetric methodology via VSP2 using customized test cells. The safety assessment of lithium-ion cells proved to be an important subject. The maximum self-heating rate (dT dt ⁻¹)_max and the largest pressure-rise rate (dP dt ⁻¹)_max of Sanyo 18650 lithium-ion battery of 100% SOC were measured to be 37,468.8 °C min⁻¹ and 10,845.6 psi min⁻¹, respectively, and the maximum temperature was 733.1 °C. Therefore, a runaway reaction is extremely serious when a lithium-ion battery is exothermic at 100% SOC. This result also demonstrated that the thermal VSP2 is an alternative method of thermal hazard assessment for battery safety research. Finally, self-reactive ratings on thermal hazards of 18650 lithium-ion batteries were studied and elucidated to a deeper extent.