Why does lithium iron phosphate battery explode

First of all, in terms of material preparation, the solid-phase sintering reaction of lithium iron phosphate is a complex multiphase reaction (although some synthesis techniques claim to be a liquid-phase synthesis process, the final high-temperature solid-phase sintering process is required). There are solid phase phosphates, iron oxides and lithium salts, plus carbon precursors and reducing gas phases. In order to ensure that the iron element in the lithium iron phosphate is positively divalent, the sintering reaction must be carried out in a reducing atmosphere, and a strong reducing atmosphere will reduce the positive divalent iron ions in the process of reducing the ferric ions to positive divalent iron ions. The possibility of further reduction of iron ions to trace elemental iron. Iron is the most contraindicated substance in batteries. It can cause battery short circuits. This is one of the important reasons why Japanese lithium-ion batteries do not use lithium iron phosphate. In addition, the slowness and incompleteness of the solid-state reaction make there may be traces of Fe2O3 in the lithium iron phosphate. The Argonne laboratory attributed the poor high-temperature cycle of lithium iron phosphate to the dissolution of Fe2O3 and the precipitation of iron on the negative electrode during the charge-discharge cycle. In addition, in order to improve the performance of lithium iron phosphate, it must be nano-processed. A notable feature of nanomaterials is their low structure, thermal stability and high chemical activity, which to a certain extent adds the possibility of iron dissolution in lithium iron phosphate, especially under high temperature cycling and storage conditions. The experimental results also show that chemical analysis or energy spectrum analysis on the negative electrode can detect the presence of iron. From the perspective of preparing lithium iron phosphate batteries, due to the small particle size of lithium iron phosphate, the specific surface area is relatively high, and due to the carbon coating process, activated carbon with a relatively high specific surface area is very resistant to gases such as moisture in the air. Strong adsorption purpose. Lithium iron phosphate batteries have a high short-circuit rate no matter in the manufacturing process of the battery manufacturer or in the process of consumer use. Battery manufacturers often start with the battery preparation process to find the problem, and often do not recognize the problem of short-circuit caused by the inherent reasons of the lithium iron phosphate material. The American A123's 18650 lithium iron phosphate battery caught fire and exploded on an electric car several years ago, when the car was driving on the highway. Later investigations believed that the screws of the wiring were not tightened, which caused the battery to catch fire and explode due to overheating. However, some believe that the possibility of fire and explosion caused by a short circuit inside the battery is greater. It is doubtful that the heat generated when the external partial screws are not tightened will cause such a serious fire and explosion phenomenon as the 18650 lithium-ion battery. 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: What is the important performance of lithium ion battery failure