Non-aqueous electrolyte taking high temperature and low temperature into consideration and lithium ion battery

Abstract

The invention discloses a non-aqueous electrolyte considering both high temperature and low temperature. The non-aqueous electrolyte comprises a lithium salt, a non-aqueous solvent and an additive, wherein the additive at least comprises citraconic anhydride and a compound with a structure as shown in the specification, in the formula, R represents B, P, Al or Ca, and n represents an integer from 1 to 5. The invention also discloses a lithium ion battery comprising the non-aqueous electrolyte. According to the non-aqueous electrolyte with both high temperature and low temperature, the compound is matched with citraconic anhydride to serve as an additive, and the effect of taking both high temperature and low temperature into consideration is achieved.

Description

technical field [0001] The invention relates to the technical field of electrolytic solutions, in particular to a non-aqueous electrolytic solution and a lithium-ion battery with both high and low temperature. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, large specific capacity, long cycle life, no memory effect and environmental friendliness, and are widely used in digital, energy storage, power and military aerospace and other fields. As the carrier of ion transport in lithium-ion batteries, electrolyte plays a vital role in the performance of lithium-ion batteries in all aspects. [0003] When lithium-ion batteries are used as power batteries, there are requirements for both high and low temperature. In particular, soft-pack batteries must not only suppress gas production and expansion caused by high-temperature storage, but also take into account low impedance and low-temperature performance to meet power needs. The hi...

AI Technical Summary

Problems solved by technology

The high and low temperature performance of lithium-ion batteries is mainly affected by the following factors: (1) High temperature conditions are likely to aggravate the catalytic decomposition of transition metal ions to the electrolyte, and the decomposition gas products directly lead to battery thickness expansion, and the solid products are at the interface between the positive and negative electrodes. Deposition, increasing the internal resistance of the battery; (2), LiPF 6 The HF produced by decomposition under high temperature corrodes the positive electrode active material, leading to the dissolution of transition metal ions and destroying the structure of the positive electrode material; (3), the SEI film formed when the battery is charged for the first time decomposes under high temperature conditions, and the SEI film structure is easily damaged , leading to a sharp decline in battery performance; (4), the composition of the lithium-ion battery electrolyte solvent, the freezing point of the solvent, and the low-temperature viscosity of the solvent directly determine the low-temperature performance of the lithium-ion battery; (5), the interface formed by the decomposition of the lithium-ion battery electrolyte additive Membrane impedance value also has a great influence on the low temperature performance of the battery

[0004] At present, high-temperature additives commonly used in the market, such as PS and PST, have better high-temperature effects, but have relatively high impedance; another type of low-impedance additive, such as FEC, is easy to decompose and generate gas when stored at high temperature, and cannot take into account high and low temperature characteristics.

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