Secondary battery electrolyte and secondary battery

Abstract

The invention discloses a secondary battery electrolyte and a battery wherein the secondary battery electrolyte comprises an organic solvent, an electrolyte salt and an additive; the additives comprise a phosphorus compound additive A with double bonds, a difluorophosphate and / or tetrafluorophosphate additive B and a silicon-nitrogen compound additive C at the same time. The invention also provides a secondary battery. The battery comprises a shell, a battery cell and the secondary battery electrolyte, wherein the battery cell and the secondary battery electrolyte are positioned in the shell. According to the invention, the additives A, B and C are added at the same time, and the overall formula of the electrolyte is improved, so that the normal-temperature and high-temperature capacity retention rates of the secondary battery containing the electrolyte are improved, and the impedance increase of the battery at high temperature and the lithium precipitation phenomenon at low temperature are inhibited.

Description

technical field [0001] The invention belongs to the technical field of secondary batteries, and in particular relates to a secondary battery electrolyte and a secondary battery. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, good cycle performance, long storage time, and small self-discharge. As ideal energy storage devices, they are expected to gradually replace traditional energy storage devices, such as lead-acid batteries, nickel-cadmium batteries, and nickel-metal hydride batteries. With the expansion of lithium-ion battery applications and the development of modern information technology, higher requirements are put forward for lithium-ion batteries. Therefore, how to meet the requirements has become an urgent problem in the industry. [0003] There are many factors that affect the rapid charge and discharge of lithium-ion batteries. As an important part of lithium-ion batteries, the electrolyte has a significant impact...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent CN100334771C proposes adding a specific concentration of phosphinate compound in the electrolyte, which can improve the high-temperature trickle charging and high-temperature storage performance of the battery, but it fails to improve the retention rate after cycle, the swelling rate at high temperature and The rate of change of internal resistance has been improved, but the effect of cycle performance, rate performance and safety performance has not been improved.

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