Anti-overcharge electrolyte of lithium-ion power battery and lithium-ion power battery

Abstract

The invention belongs to the technical field of lithium ion battery electrolytes, and in particular relates to an anti-overcharge electrolyte of a lithium-ion power battery and a lithium-ion power battery, wherein the electrolyte comprises electrolyte lithium salt, a non-aqueous organic solvent, a film-forming additive and an anti-overcharge additive, wherein the film-forming additive is at leastone of tris (trimethylsilane) borate and ethylene sulfate; the anti-overcharge additive is provided with an aromatic compound with a structure (I) formula. The anti-overcharge additive disclosed by the invention does not participate in any reaction process when the battery is at a normal working voltage of (3.0-4.3V); when the charging voltage of the battery exceeds 4.45V, the anti-overcharge additive generates redox flying shuttle shunt voltage limitation on the surface of the electrode to clamp the voltage within a certain range, so as to prevent the internal electrolyte of the battery fromviolently decomposing to generate heat and gas due to excessively high voltage, and further to avoid the battery from the safety problems such as burning, explosion and the like.

Description

Technical field [0001] The invention belongs to the technical field of lithium-ion battery electrolytes, and in particular relates to a lithium-ion power battery anti-overcharge electrolyte and a lithium-ion power battery. Background technology [0002] Lithium-ion batteries are widely used in 3C digital products, power tools, electric vehicles, energy storage equipment and other fields due to their high operating voltage, high energy density, long life and environmental friendliness. [0003] As a means of transportation, the driving range, acceleration performance, climbing ability and safety performance of electric vehicles are the focus of attention, and the level of these performance indicators mainly depends on the power battery as a key component. In order to meet the higher power battery energy density requirements in the above plan, one is to continuously increase the nickel content in cathode materials, such as NCM622, NCM811, NCA, etc., and the other is to continu...

AI Technical Summary

Problems solved by technology

Currently commonly used anti-overcharge additives (such as biphenyl, cyclohexylbenzene) can improve the overcharge safety of the battery to a certain extent, but the stability is poor during the long cycle of the battery, and it is easy to increase the internal resistance of the battery and affect the battery life. At the same time, when the battery is overcharged, this type of additive will irreversibly decompose and produce gas or electropolymerization. After the battery is overcharged, the overcharge additive will often lose its own performance.

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