Electrolyte of high-voltage fast-charging lithium ion battery and lithium ion battery

Abstract

The invention discloses an electrolyte of a high-voltage fast-charging lithium ion battery and the lithium battery. The electrolyte comprises a non-aqueous organic solvent, an electrolyte salt and anadditive, and the mass percentages of the non-aqueous organic solvent, the electrolyte salt and the additive in the electrolyte are 65%-90%, 10%-20% and 0-15% respectively. The electrolyte can improvethe normal-temperature quick charge cycle performance, the high-temperature storage performance and the low-temperature discharge performance of the high-voltage battery at the same time. The lithiumion battery prepared by adopting the electrolyte has lower surface density, is beneficial to reducing the impedance of the lithium ion battery, is smoother in lithium ion migration, can effectively improve the rate charge-discharge performance, and obviously improves the low-temperature discharge performance at the same time; the electrolyte of the high-voltage fast-charging lithium ion battery has the relatively high charging cut-off voltage, the capacity of the lithium ion battery can be improved by about 15%, and energy density reduction caused by surface density reduction is made up; andcompared with a conventional battery, the lithium ion battery has wider tabs, so that the ohmic impedance of the lithium ion battery is effectively reduced to facilitate electron transmission.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to an electrolyte solution for a high-voltage super fast-charge lithium-ion battery and a lithium-ion battery using the electrolyte solution. Background technique [0002] With the emergence of emerging consumer fields such as mobile phones, tablet computers, smart wearables, and ETC, lithium-ion batteries have shown great advantages due to their high energy density and long cycle life. However, with the continuous diversification of corresponding equipment functions and the continuous increase of power consumption of power modules, it is difficult for conventional lithium-ion batteries to meet the needs of users. In order to improve user experience, the development direction of lithium-ion batteries has become increasingly clear, that is, to increase energy density as much as possible or to achieve fast charging under safe conditions. [0003] In order to improve energy densit...

AI Technical Summary

Problems solved by technology

However, the current fast charging electrolyte has the following three problems: ①The dynamic performance of the conventional electrolyte is not high enough (poor wettability, high viscosity), and the resistance of lithium ions in the mass transfer process is relatively large; ②The composition of the electrolyte and the positive and negative The degree of matching is low, the battery polarization is large, and high-rate charging can easily lead to lithium deposition at the negative electrode; ③ After the battery is charged and discharged with a large current, it is difficult to guarantee the life and safety of the battery

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