Authors:Chia-Yuan Wen, Can-Yong Jhu, Yih-Wen Wang, Chung-Cheng Chiang, and Chi-Min Shu
In view of availability, accountability, and applicability, LiFePO4 cathode material has been confirmed to be better than LiCoO2 cathode material. Nevertheless, few related researches were conducted for thermal runaway reaction of the LiFePO4 batteries. In this study, vent sizing package 2 (VSP2) and differential scanning calorimetry were employed to observe the thermal hazard of 18650 lithium-ion batteries and their content—LiFePO4 cathode material, which were manufactured by Commercial Battery, Inc. Two states of the batteries were investigated, which was charged to 3.6 V (fully charged) and 4.2 V (overcharged), respectively, and important parameters were obtained, such as self-heating rate (dT dt−1), pressure-rise rate (dP dt−1), and exothermic onset temperature (T0). The results showed that T0 for fully charged is about 199.94 °C and Tmax is about 243.23 °C. The entire battery for LiFePO4 cathode material is more stable than other lithium-ion batteries, and an entire battery is more dangerous than a single cathode material. For process loss prevention, the data of battery of VSP2 test were applied as reference for design of safer devices.
Authors:Yu-Chuan Liang, Can-Yong Jhu, Sheng-Hung Wu, Sun-Ju Shen, and Chi-Min Shu
Methyl ethyl ketone peroxide (MEKPO) is generally applied to manufacturing in the polymerization processes. Due to thermal instability and high exothermic behaviors of MEKPO, if any operation is undertaken recklessly or some environmental effect is produced suddenly during the processes, fires and explosions may inevitably occur. In this study, thermal analysis was evaluated for MEKPO by differential scanning calorimetry (DSC) test. Vent sizing package 2 (VSP2) was used to analyze the thermal hazard of MEKPO under various stirring rates in a batch reactor. Thermokinetic and safety parameters, including exothermic onset temperature (T0), maximum temperature (Tmax), maximum pressure (Pmax), self-heating rate (dT dt−1), pressure rise rate (dP dt−1), and so on, were discovered to identify the safe handling situation. The stirring rates of reactor were confirmed to affect runaway and thermal hazard characteristics in the batch reactor. If the stirring rate was out of control, it could soon cause a thermal hazard in the reactor.