What are the root causes of the burning and explosion of soft-pack polymer lithium-ion batteries?

The soft-pack polymer lithium-ion battery is a kind of lithium-ion battery product made by recycling flexible packaging and polymer electrolyte. It will not explode in normal use and storage, unless it is short-circuited by the strong crush of wages. The current polymer lithium-ion batteries are mostly soft-packed batteries, and the aluminum plastic film is recycled as the outer shell. When the organic electrolyte is recycled inside, the liquid will not explode even if the liquid is hot, because the aluminum plastic film polymer battery recycles solid or colloidal without leakage. Liquid is just a natural division. However, any work is not absolute. If the instantaneous current is large enough to produce a short circuit, it is not impossible for the battery to spontaneously ignite or burst. The safety of mobile phones and computers are mostly caused by this environment. In order to eliminate the occurrence of explosions, polymer lithium-ion batteries are being used in more and more places. Although lithium-ion batteries are still in the process of replacing other types of batteries, in the case of lithium-ion batteries, polymer lithium-ion batteries have already begun. Replace ordinary lithium-ion batteries on a departmental scale. Conditions for the explosion and combustion of polymer lithium-ion batteries 1. The soft-pack lithium-ion battery is seriously overcharged, and the chemical system of the lithium-ion battery is determined. When the battery is overcharged, the LiCoO2 inside the battery becomes Co3O4, and Co3O4 is very Strong oxidant, it can react with electrolyte and present gas (O2). When the cell voltage reaches close to 5V, as the internal temperature of the cell rises and the gas pressure is used, most cells will burn or explode due to internal short circuits and other reasons. 2. The cell is heated by high temperature. When the cell is heated at high temperature, the electrolyte will vaporize and resolve at the same time. The internal pressure of the cell will increase, and the insulation film inside the cell will probably melt, causing the internal short circuit of the cell to cause combustion, and the cathode When the material is full of electricity, at a certain temperature, it will produce an autocatalytic reverberation, showing combustion. 3. The battery core is short-circuited, and the battery core is suddenly short-circuited when it is fully charged. This may cause the battery core to appear safe and disordered. To deal with the problems in the above-mentioned aspects, it is important to take care of the battery cells by adopting the essentials of protective boards, PTCs, special chargers and fuses. Among them, the protection board is the first-level protection for the overcharge, over-discharge and over-current of the battery cell. The PTC is the second-level protection for the battery cell under the short-circuit and high-current environment when the battery is overheated. The special charger is The charging current and voltage of the battery are restricted, and the fuse is used less now. Its important purpose is to completely cut off the connection between the battery and the external circuit when the battery voltage or current is abnormal, so as to ensure that the battery will not be used again. , To ensure that the battery cell will not present a serious safety disturbance. How to prevent polymer lithium ion batteries from exploding? All lithium-ion battery explosions are caused by battery fever caused by a short circuit. The reasons for the short circuit are overcharge, overdischarge, direct connection of positive and negative electrodes, and electrolyte leakage. Therefore, in the design of lithium-ion batteries, the following points can be started: 1. restrain the battery from overcharging above 4.2V; 2. restrain the battery from overdischarging below 2.75V; 3. install an explosion-proof valve on the metal shell; statement: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete the previous article: What are the essentials to increase the capacity of lithium-ion batteries?