Rate type lithium ion battery electrolytic solution with high and low temperature performance and lithium ion battery

Abstract

The invention discloses a rate type lithium ion battery electrolytic solution with high and low temperature performance. The rate type lithium ion battery electrolytic solution comprises an organic solvent, a lithium salt and a functional additive, wherein the organic solvent comprises cyclic carbonate and fluoro linear carboxylic ester, the lithium salt comprises a first lithium salt and a second lithium salt, the first lithium salt is lithium hexafluorophosphate, the second lithium salt is at least one of lithium difluorophosphate, lithium difluoro oxalate phosphate and lithium perfluoroalkyl sulfonimide, and the functional additives comprise a high-temperature additive and a low-temperature additive. The invention also discloses a lithium ion battery containing the electrolytic solution. According to the invention, the proper organic solvent, the lithium salt and the additive are matched, so that the electrolytic solutionhas a wider temperature window of -30 to 60 DEG C, and high and low temperature performance can be considered.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a rate-type lithium-ion battery electrolyte and a lithium-ion battery that take into account both high and low temperature performance. Background technique [0002] Lithium-ion batteries are widely used because of their high working voltage, large specific energy, long cycle life and no memory effect. For example, lithium-ion batteries have been widely used in the field of 3C consumer electronics products, and with the new With the development of energy vehicles, lithium-ion batteries are also widely used in the field of power and energy storage. [0003] During the use of lithium-ion batteries, it has always been the focus of research by battery scientists to take into account the performance at high and low temperatures. Generally speaking, batteries with good performance at room temperature can only take into account good low-temperature performance or high-temp...

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Problems solved by technology

[0003] During the use of lithium-ion batteries, it has always been the focus of research by battery scientists to take into account the performance at high and low temperatures. Generally speaking, batteries with good performance at room temperature can only take into account good low-temperature performance or high-temperature performance, which is difficult. Achieve both high and low temperature performance

The most important reason is that the liquid temperature window of the lithium-ion battery electrolyte is narrow, and it cannot take into account the thermal stability and electrochemical stability at high and low temperatures. The publication number is CN103985906B invention patent provides a lithium-ion battery with high and low temperature performance Electrolyte, including: lithium hexafluorophosphate, mixed organic solvents, film-forming additives, additives to improve dielectric constant and low-temperature wetting ability, and lithium salt-type additives. The batteries prepared with this lithium-ion battery electrolyte with both high and low temperature performance have a long cycle life , and not only ensure that the battery has good low-temperature discharge performance, but also effectively take into account the storage performance of the battery at a high temperature of 60°C; CN107195966B invention patent discloses a lithium-ion battery electrolyte, and fluorobenzene is added to the lithium-ion battery electrolyte at the same time Nitrile, fluorobenzene, lithium oxalate phosphate, and lithium fluorophosphate are four additives. The simultaneous use of the above additives will produce a synergistic effect, making the ternary positive electrode material battery have an excellent cycle under high voltage (4.3 ~ 4.5V) conditions Excellent performance, high temperature storage performance, low temperature discharge performance and safety performance, etc., which solves the problem that the electrolyte cycle performance, high temperature performance and low temperature performance cannot be taken into account in the prior art.

[0004] However, the problem with the above-mentioned scheme is that the low-melting-point solvent and low-impedance film-forming additives that need to be used for large logarithms are generally not compatible with the graphite negative electrode interface, and it is necessary to match appropriate lithium salts and other additives to inhibit the impact of such solvents on graphite. Delamination of the negative electrode

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