Lithium secondary battery overcharge protection electrolyte and lithium secondary battery

A lithium secondary battery and overcharging technology, which is applied in secondary batteries, secondary battery repair/maintenance, lithium batteries, etc., can solve the problems affecting the long cycle life of the battery, the battery cannot be used continuously, and the internal resistance of the battery is increased. Achieve the effects of improving kinetic properties, reducing reactivity, and avoiding combustion and explosion

Inactive Publication Date: 2017-02-22
GUANGZHOU TINCI MATERIALS TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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 such additives block the overcharge of the battery, the irreversible decomposition and gas generation or electropolymerization will occur. After the battery is overcharged, it will not be able to continue to be used.

Method used

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  • Lithium secondary battery overcharge protection electrolyte and lithium secondary battery
  • Lithium secondary battery overcharge protection electrolyte and lithium secondary battery
  • Lithium secondary battery overcharge protection electrolyte and lithium secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Electrolyte preparation steps: In a glove box filled with argon, mix ethylene carbonate, diethyl carbonate and ethyl methyl carbonate at a mass ratio of EC: DEC: EMC = 3: 2: 5, and then add to the mixed solution Slowly add 1.0mol / L lithium hexafluorophosphate, 0.02mol / L lithium difluorophosphate and 0.02mol / L lithium bisfluorosulfonimide, and finally add 0.5wt% of tris(trimethylsilane) based on the total weight of the electrolyte Phosphoric acid ester (TMSP), 1wt% vinyl sulfate (DTD), 0.2wt% vinylene carbonate (VC) and 2wt% 2,4-difluoroanisole were stirred uniformly to obtain the lithium secondary battery of Example 1 Electrolyte.

[0025] Inject the prepared lithium secondary battery electrolyte into the fully dried silicon-carbon composite / LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 In the power battery, after the battery is placed at 45°C, formed into a high-temperature clamp, and sealed again, it is conventionally divided.

[0026] 1) Normal temperature cycle performance test: At 25℃, ...

Embodiment 2~8

[0032] Examples 2 to 8 and Comparative Examples 1 to 4

[0033] In Examples 2 to 8 and Comparative Examples 1 to 4, except that the composition ratio of each component of the electrolyte is added as shown in Table 1, the others are the same as in Example 1. Table 1 shows the composition ratios of the electrolyte components of Examples 1-8 and Comparative Examples 1-4:

[0034]

[0035]

[0036] Table 1

[0037] In Table 1 above, the abbreviations / chemical formula corresponding names of each chemical substance are as follows:

[0038] LiPF 6 (Lithium hexafluorophosphate), LiPO 2 F 2 (Lithium difluorophosphate), LiFSI (lithium bisfluorosulfonimide), EC (ethylene carbonate), DEC (diethyl carbonate), EMC (ethyl methyl carbonate), DMC (dimethyl carbonate), PC (Propylene carbonate), DTD (vinyl sulfate), TMSP (tris(trimethylsilane) phosphate), VC (vinylene carbonate), PS (1,3-propane sultone).

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Abstract

The invention discloses lithium secondary battery overcharge protection electrolyte and a lithium secondary battery. The electrolyte contains electrolyte lithium salts, non-water organic solvents, film forming additives and overcharge protection additives, wherein the film forming additives are at least one kind of materials from TMSP (tris(trimethylsilyl) phosphate) and DTD (dioxathiolane 2,2-dioxide); the overcharge protection additives comprise oxidation and reduction shuttle type overcharge protection additives. The overcharge protection additives used in the electrolyte do not take part in any reaction process at the normal work voltage of 2.75 to 4.35V; when the battery charging voltage exceeds 4.4V, the oxidation and reduction shuttle type overcharge protection additives generate oxidation and reduction shuttle current distribution and voltage limitation on the surface of an electrode; the voltage is controlled to be within a range; the intense decomposition of the electrolyte inside the battery due to too high voltage can be avoided; further, the occurrence of safety problems of combustion, explosion and the like of the battery can be prevented.

Description

Technical field [0001] The invention relates to the field of lithium secondary batteries, in particular to a lithium secondary battery anti-overcharge solution and the lithium secondary battery. Background technique [0002] Lithium secondary batteries are widely used in 3C digital products, power tools, electric vehicles, aerospace and other fields because of their high working voltage, high energy density, long life and environmental friendliness. Especially in the field of electric vehicles, there has been explosive growth since 2015. According to the National Development Plan for Energy Conservation and New Energy Automobile Industry, the energy density of power batteries is required to reach 300Wh / Kg or more by 2020. [0003] As a means of transportation, electric vehicles have their driving range, acceleration performance, climbing ability and safety performance are the focus of attention, and the level of these performance indicators mainly depends on the power battery as a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0567H01M10/052H01M10/42
CPCH01M10/052H01M10/0567H01M10/4235H01M2300/0025Y02E60/10
Inventor 潘立宁吕家斌徐朝银万华平仰永军彭宏伟粟彬
Owner GUANGZHOU TINCI MATERIALS TECH
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