What are the current safety hazards of lithium batteries?

The safety of lithium batteries is not only related to the nature of the pool data itself, but also related to the preparation technology and application of the battery. Mobile phone batteries explode time and time again, on the one hand because of maintenance circuit failure, but more importantly, there is no fundamental problem in data processing. Lithium cobalt oxide cathode active material is a very complicated system in small batteries, but there are still a lot of lithium ions in the anode. When overloaded, the remaining anode lithium ions will rush to the anode, and the cathode dendritic composition is the choice material lithium cobalt oxide A necessary result of battery overcharging. Even in the process of normal charging and discharging, it is possible to have the rest of the lithium ion cathode dendrites. The theoretical energy ratio of the cobalt lithium oxide material is greater than 270 mAh/g, but in order to ensure its cycle function, The theoretical capacity used in practice is only half of the capacity. During use, due to the excessively high charging voltage of the battery (such as damage to the management system), the remaining lithium in the positive electrode will be precipitated, and it will accumulate in the form of metallic lithium on the surface of the negative electrode to form dendrites. The dendrites pierce through the gap and form an internal short circuit. The first component of the electrolyte is carbonate, which has a low flash point and boiling point. If the battery is overheated, the carbonate in the electrolyte will be oxidized and recovered, resulting in a large amount of gas and heat. For example, a short safety valve may not be able to release gas through the safety valve, and the internal pressure of the battery rises sharply, causing an explosion. Lithium batteries and polymer electrolytes do not fundamentally deal with safety issues. They also use lithium cobalt oxide and organic electrolytes, and the electrolyte is colloidal, not easy to leak, and will be more violent when burned. Combustion is the biggest problem in polymer battery safety. There are also some problems in use. The internal or external short circuit of the battery will cause an excessive current of several hundred amperes. When the external short-circuit battery is discharged with a large current in an instant, a large amount of energy is consumed in the internal resistance, and a large amount of heat appears. The internal short circuit constitutes a large current, the temperature rise causes the gap to melt, and the short circuit area expands, thereby forming a vicious circle. In order to achieve a high working voltage of 3~4.2v for a single cell, an organic electrolyte with a decomposition voltage greater than 2V should be used for electrolysis under high current and high temperature conditions. The electrolysis attack of the gas will cause the internal pressure of the shell to increase, which will cause a serious breakthrough in the shell. Overcharge can separate the metal lithium. In the case of splitting, it will be in direct contact with the air, resulting in incineration, electrolyte ignition, fierce flame attack, rapid gas expansion, and attack blasting. In addition, with regard to mobile phone lithium batteries, due to improper use, such as kneading, impact and water ingress, the battery swells, deforms and cracks, which will cause the battery to short-circuit, and the heat generated during the discharge or charging process will be blown up. 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 are the two types of lithium batteries?