How to solve the safety problem of lithium battery?

1Improving the safety of the electrolyte There is a high reaction activity between the electrolyte and the positive and negative electrodes, especially at high temperatures. In order to improve the safety of the battery, improving the safety of the electrolyte is one of the more effective methods. The potential safety hazards of electrolyte can be effectively solved by adding functional additives, using new lithium salts and using new solvents. According to the different functions of additives, the important ones can be divided into the following categories: safety protection additives, film-forming additives, positive electrode protection additives, stabilizing lithium salt additives, lithium precipitation promoting additives, current collector anticorrosive additives, and wettability enhancing additives. In order to improve the performance of commercial lithium salts, researchers have substituted atoms for them and obtained many derivatives. Among them, compounds obtained with perfluoroalkyl substituted atoms have many advantages such as high flash point, similar conductivity, and enhanced water resistance. , Is a kind of lithium salt compound with great application prospects. In addition, the anionic lithium salt obtained by chelating with an oxygen ligand with a boron atom as the central atom has high thermal stability. Regarding solvents, many researchers have proposed a series of new organic solvents, such as carboxylic acid esters and organic ethers. In addition, ionic liquids also have a class of electrolytes with high safety, but relatively commonly used carbonate-based electrolytes. The viscosity of ionic liquids is orders of magnitude higher, and the conductivity and ion self-diffusion coefficient are low. There is still a lot of work before practicality. To do. 2Improving the safety of electrode materials Lithium iron phosphate and ternary composite materials are considered to be low-cost, high-safety cathode materials, and may be popularized in the electric vehicle industry. Regarding the positive electrode material, the common method to improve its safety is coating modification. For example, the surface coating of the positive electrode material with a metal oxide can prevent the direct contact between the positive electrode material and the electrolyte, inhibit the phase change of the positive electrode material, and improve Its structural stability reduces the disorder of cations in the crystal lattice to reduce heat generation by side reactions. Regarding the negative electrode material, because the surface of the lithium battery is often the most prone to thermochemical decomposition and heat generation, improving the thermal stability of the SEI film is a key method to improve the safety of the negative electrode material. Through weak oxidation, metal and metal oxide deposition, polymer or carbon coating, the thermal stability of the negative electrode material can be improved. 3Improve battery safety protection design. In addition to improving the safety of battery materials, commercial lithium batteries adopt many safety protection measures, such as setting battery safety valves, thermal fuses, connecting parts with positive temperature coefficients in series, using heat-sealed diaphragms, and special loading Protection circuits, dedicated battery management systems, etc. are also means to enhance safety. 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 differences between polymer batteries and lithium batteries?