Electrolyte of rapid-charging lithium ion battery

Abstract

The invention relates to technical field of a lithium ion battery, in particular to an electrolyte of a rapid-charging lithium ion battery. The electrolyte comprises a solvent, a lithium salt and an additive, wherein the solvent contains more than two mixtures of linear carbonic ester with a low boiling point, linear carboxylic ester, fluorobenzene and hydrofluoroether, and the additive comprises a first additive for negative electrode film forming, a second additive for improving the cycle performance of the battery and a third additive for improving the high-temperature performance of the battery. Compared with the prior art, the organic solvent and the three additives are used in a combination way to generate a synergistic effect, the rapid charging demand of a high-potential, high-compaction-density and more than 2C rapid-charging system battery with a voltage of 4.35V and negative electrode compaction density of over 1.6g/cm<3> can be met, and meanwhile, the electrolyte has favorable cycle performance and high- and low-temperature performance.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a fast-charging lithium-ion battery electrolyte. Background technique [0002] Lithium-ion batteries are widely used in 3C digital products, electric vehicles, military aerospace and other fields due to their high working voltage, high energy density, long cycle life, and environmental friendliness. With the popularization of smart digital products and the wider application of new energy vehicles, people's demand for fast charging is more urgent. Shortening the charging time can improve user experience. Fast charging technology is an important direction for the development of battery cells in the future. [0003] The development of fast charging technology is influenced in many ways. From the perspective of the battery cell itself, battery design, positive and negative electrode materials, and electrolyte are the keys to the fast charging technology of the battery....

AI Technical Summary

Problems solved by technology

[0004] In the prior art, organic solvents with low boiling points are mostly used to improve the kinetic properties of the electrolyte, such as linear dimethyl carbonate, ethyl methyl carbonate, ethyl acetate, propyl acetate and other organic solvents with low viscosity, It can provide a more suitable channel for lithium ion transmission, but the use of these solvents will challenge the high temperature performance of the battery, and the poor compatibility of carboxylate organic solvents with the graphite of the negative electrode of the battery will deteriorate the cycle performance of the battery

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