Lithium ion battery electrolyte, additive of lithium ion battery electrolyte, lithium ion battery cell, lithium ion battery pack and application of lithium ion battery pack

Abstract

The invention discloses a lithium ion battery pack, a lithium ion battery cell, a lithium ion battery electrolyte and an additive thereof. The electrolyte additive comprises a fluorinated benzene ring anhydride additive, and an anhydride functional group in the fluorinated benzene ring anhydride additive is a cyclic anhydride functional group. Specifically, the fluorinated benzene ring anhydride additive simultaneously contains three functional groups, namely fluorine, a benzene ring and anhydride, wherein the benzene ring can be subjected to electropolymerization to form a film on a positive electrode, the anhydride can be easily subjected to a reduction film-forming reaction on a negative electrode interface, and fluorine atoms can be combined with lithium in the electrolyte to form LiF to increase the stability of an interface film. The synergistic interaction of the three functional groups is beneficial to the protection of positive and negative electrode interfaces, so that the direct contact between the electrolyte and the electrode interfaces is effectively isolated, and the electrochemical performance of the battery under different working conditions is improved. The additive effectively improves the high-voltage cycle stability of the battery and the storage and cycle performance under a high-temperature condition, and also can consider the safety characteristic of the lithium ion battery.

Description

technical field [0001] The invention relates to the field of energy storage, in particular to a lithium-ion battery electrolyte and its additive, a lithium-ion battery cell, a lithium-ion battery pack and applications thereof. Background technique [0002] With the rapid development of new energy vehicles, the market has put forward higher requirements for the safety and cruising range of electric vehicles. Lithium-ion batteries are widely used in the field of new energy vehicles because of their high energy density, no memory effect, and environmental friendliness. Lithium-ion batteries, as the core power components of electric vehicles, are mainly composed of four parts: positive electrode, negative electrode, electrolyte and separator. The capacity of the battery is mainly determined by the positive and negative electrode materials. Improving the charge cut-off voltage of the battery is an effective way to increase the energy density of the battery, but for batteries wit...

AI Technical Summary

Problems solved by technology

However, most additives can only protect the positive or negative electrodes alone, and cannot protect the positive and negative interfaces at the same time. In practical applications, two or more additives need to be added in combination.

Most additives are generally expensive and harmful to the human body, which will easily cause the increase of battery cost and the pollution of the environment

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