Analysis on the cause of fire and explosion of lithium battery

The cause of fire and explosion of lithium battery When the lithium battery is charged, when the voltage rises, the positive and negative electrodes will become a strong redox state, so the material is easy to be unstable. (1) Overcharge. Charging over time is called overcharging, because the battery will generate heat and flammable gas will appear in the electrolyte. Generally speaking, in an overcharged battery, a reduction reaction occurs between the electrolyte and the negative electrode first, and then the thermal decomposition of the electrolyte between the electrolyte and the positive electrode is shown in Figure 7. Overview of the polymer lithium battery Figure 8 Schematic diagram of the polymer lithium battery structure. Oxidative decomposition thermal decomposition of negative thermal decomposition of positive thermal decomposition will eventually lead to a short circuit of melt flow inside the separator. Positive electrode: It generates heat due to the destruction of the oxidized crystal structure of the electrolyte. Cathode: Lithium metal precipitation. (2) Discharging. Overdischarge is called overdischarge, and overcharge will generate heat. Positive electrode: fusion of cobalt. Cathode: The collector is melted (copper). In short, in either case, the electrodes, electrolyte, and separator will melt due to heating, causing internal short circuits. Joule heat will spread around until it comes into contact with flammable electrolyte (combustible gas) and catches fire. When the battery is heated from the outside due to a fire, the positive electrode material, the electrolyte and the negative electrode material react separately. The separator melts, the electrodes are short-circuited, and Joule heat begins to diffuse. In addition, due to external shocks, the insulation and isolation plates of each electrode are damaged. Although there is no fire, short circuits and fires sometimes occur inside during charging. Due to the high energy density, the temperature rises sharply during a short circuit, and the electrolyte becomes an organic solvent, which is easy to catch fire. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Frequently asked questions about lithium batteries