What caused the lithium-ion battery to catch fire?

The essence of the ignition of lithium-ion batteries is that the heat in the battery fails to be released according to the design intent, causing internal and external combustion materials to ignite after ignition. The main causes are external short circuit, external high temperature and internal short circuit. 1. Internal short circuit due to the abuse of the battery, such as the branch crystal caused by overcharge and overdischarge, the impurity dust in the battery production process, etc., will deteriorate to pierce the diaphragm, cause a micro short circuit, and the release of electric energy will cause temperature rise and temperature rise The chemical reaction of the incoming materials expands the short-circuit path and forms a larger short-circuit current. This mutually accumulating and mutually reinforcing destruction leads to thermal runaway. 2. The external short circuit is an example of an electric vehicle. The probability of danger in actual vehicle operation is very low. One is that the vehicle system is equipped with fuses and a battery management system BMS, and the other is that the battery can withstand a short-term high current impact. In extreme cases, the short-circuit point crosses the vehicle fuse and the BMS fails. A long-term external short-circuit will generally cause the weak points in the circuit to be burned, and rarely cause thermal runaway events in the battery. Now, more PACK companies have adopted the method of adding fuses in the loop, which can more effectively prevent the hazards caused by external short circuits. 3. Due to the characteristics of the structure of the lithium ion battery, the SEI film, electrolyte, EC, etc. will undergo decomposition reactions at high temperatures. The decomposition products of the electrolyte will also react with the positive and negative electrodes, and the battery diaphragm will melt and decompose. The reaction causes a lot of heat to appear. The melting of the diaphragm causes an internal short circuit, and the release of electrical energy increases the heat production. This cumulative and mutually reinforcing destructive use results in the explosion of the explosion-proof membrane of the battery cell, the ejection of electrolyte, and the occurrence of combustion and fire. We understand the causes of lithium-ion battery fires, and understand that lithium-ion battery fires are extremely difficult to control. Therefore, once you find signs of smoking, fire, etc. in the use of electric vehicles, you must escape as soon as possible. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What is the new energy vehicle battery?