Three reasons why lithium-ion batteries burn and explode

There are three reasons for the burning and explosion of lithium-ion batteries: 1. When the lithium-ion battery is heated, the internal reactions of the battery are like a reaction chain, and each reaction promotes each other and proceeds in sequence. The first is that the SEI film releases heat to heat the battery, which promotes the reaction between the negative electrode and the solvent to release more heat, leading to the reaction between the negative electrode and the binder and solvent decomposition, and then the positive electrode begins to undergo thermal decomposition reaction, releasing a large amount of heat and gas. , Finally causing the battery to burn or explode. 2. In the initial stage of lithium-ion battery charging, part of the electrical energy is converted into heat energy when the current passes through the battery, and part of the heat also appears in ohmic polarization, but the surface temperature of the battery rises very slowly; when the battery reaches a fully charged state, the lithium continues the intercalation reaction It becomes the deposition of lithium ion metal on the surface of the negative electrode, and the solvent is oxidized (the heat released by the oxidation reaction of the solvent caused by overcharge is much higher than the heat released by the reaction between lithium and the solvent in the reversible state), and the heat released heats the battery; As the battery temperature rises, the reaction of metal lithium ions with the solvent, and the reaction of the lithium ion carbon with the solvent occur successively, and the heat is out of control. At the same time, the decomposition of the solvent and the reaction between the binder and the lithium ion metal occur. 3. The harm caused by short circuit, needle stick and impact to lithium-ion battery is roughly the same. When a short circuit occurs, a large amount of heat appears when the current passes through the battery, heating the battery, and the battery temperature rises to the temperature at which the positive electrode decomposes, and the thermal decomposition of the positive electrode causes the battery heat to run out of control; when the needle puncture speed is very fast, it will cause localization at the needle puncture site. A short circuit and a large amount of heat will cause the internal temperature of the battery to rise to the temperature at which the positive electrode is thermally decomposed; when the lithium ion battery is impacted, the overvoltage loss on the electrode will cause heat to promote the reaction between the solvent and the negative electrode, and the heat released will further heat the battery , Which promotes the thermal decomposition reaction of the positive electrode to occur, causing the heat to run out of control. 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 post: What is the important reason for the explosion of the lithium ion battery?