Functional additive for lithium ion battery electrolyte, lithium ion battery electrolyte and lithium ion battery

Abstract

The invention relates to a functional additive for a lithium ion battery electrolyte, the lithium ion battery electrolyte and a lithium ion battery and belongs to the technical field of lithium ion batteries. The functional additive is prepared from the components in parts by weight as follows: 0.5-3 parts of vinylene carbonate, 0.1-2 parts of lithium difluoro(oxalato) borate, 0.1-2 parts of lithium difluoro phosphate, 3-5 parts of fluorobenzene and 0.1-1 part of methylene methanedisulfonate. The electrolyte comprises lithium salt, an organic solvent and the functional additive, wherein the mass percents of the components of the functional additive in the electrolyte are as follows: 0.5%-3% of vinylene carbonate, 0.1%-2% of lithium difluoro(oxalato) borate, 0.1%-2% of lithium difluoro phosphate, 3%-5% of fluorobenzene and 0.1%-1% of methylene methanedisulfonate. The invention further relates to the lithium ion battery using the electrolyte. The high-temperature cycle performance of the lithium ion battery is significantly enhanced.

Description

technical field [0001] The invention relates to a functional additive for lithium-ion battery electrolyte, lithium-ion battery electrolyte and lithium-ion battery, belonging to the technical field of lithium-ion batteries. Background technique [0002] Today's issues about energy and environmental protection have attracted much attention, and electric vehicles have become one of the trends and directions of the development of the automotive industry. According to the needs of the sustainable development strategy, the Chinese government actively promotes the research, development and industrialization of electric vehicles, from key components to complete vehicle applications. [0003] Although the technical routes for the development of electric vehicles vary from country to country, power batteries, as a key component of electric vehicles, have long been valued by researchers. Due to its high energy density, good cycle performance, high safety and reliability, and strong en...

AI Technical Summary

Problems solved by technology

After the battery is charged and discharged 140 times at 0.5C at 55°C, the discharge specific capacity is about 90%. It can be expected that after 500 times of charge and discharge with a large current of 1C, the discharge specific capacity must be less than 90%, so the electrolyte cannot Meet the needs of high current and repeated discharge

Patent CN104781976A (application date 2014.02.20) discloses a non-aqueous electrolyte solution comprising a non-aqueous organic solvent, a lithium salt and an electrolyte solution additive; the non-aqueous solvent includes linear carbonate and cyclic carbonate or a combination thereof; The lithium salt includes LiPF 6 , LiN(CF 3 SO 2 ) 2 , LiN(C 2 f 5 SO 2 ) 2 and other lithium salts; the electrolyte solution additive is composed of lithium difluorophosphate (LiDFP), vinylene methyl carbonate, and sultone, but it is charged at 55°C at 1C, and the capacity retention rate after 500 cycles of 3C discharge is still not good. fulfil requirements

Patent CN102064344A (application date 2010.12.21) discloses a new type of electrolyte solution for power batteries, which improves the cycle performance of lithium-ion batteries under high temperature conditions by regulating the additives in the formulation system, and proves that the addition of methylene disulfonate ( MMDS) can significantly improve the cycle capacity retention at room temperature, but does not disclose its cycle capacity retention at high temperature