High-voltage lithium ion battery

Abstract

The invention discloses a high-voltage lithium ion battery, which comprises a positive electrode plate, a negative electrode plate, a diaphragm and electrolyte, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode slurry material coating the surface of the positive electrode current collector; the positive electrode slurry material comprises a positive electrode active substance, a conducting agent A and a bonding agent A; the negative electrode plate comprises a negative electrode current collector and a negative electrode slurry material coating the surface of the negative electrode current collector; the negative electrode slurry material is prepared from a negative electrode active substance, a conducting agent B, a dispersing agent and a bonding agent B; the electrolyte is prepared from lithium salt, non-aqueous organic solvents and additives of lithium difluorophosphate. The LiDFP is used as an electrolyte additive; the HOMO energy stage is higher than that of the electrolyte solvent molecules; the oxidization reaction can preferentially occur on the surface of the positive electrode; the stable SEI film is formed; the decomposition reaction of the electrolyte is inhibited; the loss of the nonreversible energy is reduced; the normal temperature circulation performance of the high-voltage lithium ion battery can be obviously improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high-voltage lithium ion battery. Background technique [0002] In order to meet the needs of large-scale and dynamic electric vehicles, the development of lithium-ion batteries with high energy density has become an inevitable trend. Improving the working voltage is an effective way to increase the energy density of lithium-ion batteries, and high working voltage has higher requirements on the battery material system, especially the electrochemical stability of the electrolyte. The development of high-safety, high-voltage functional electrolytes is the key to high specific energy batteries. important direction of research and development. [0003] The currently used electrolyte system is mainly composed of lithium salts and carbonate-based organic solvents. Under high voltage, carbonate-based solvents will undergo oxidative decomposition reactions an...

AI Technical Summary

Problems solved by technology

[0003] The currently used electrolyte system is mainly composed of lithium salts and carbonate-based organic solvents. Under high voltage, carbonate-based solvents will undergo oxidative decomposition reactions and form a passivation film with high impedance on the surface of the positive electrode material. At the same time, the positive electrode The catalysis and surface effects of transition metal atoms in the material intensify the occurrence of decomposition reactions, increasing the irreversible capacity loss and reducing the Coulombic efficiency, and the cycle life of the battery is also rapidly shortened.

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