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Negative electrode of high-specific energy lithium-ion battery and preparation method of negative electrode

A lithium-ion battery, negative electrode technology, applied in battery electrodes, batteries, secondary batteries, etc., can solve problems such as electrode collapse and fall off, and achieve the effect of offsetting volume expansion, reducing unsafe risks, and improving bonding strength

Inactive Publication Date: 2018-06-22
SHANXI CHANGZHENG POWER TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the expansion problem of silicon itself, the volume change of 300% during the charging and discharging process will cause the electrode to collapse and fall off. Therefore, it needs to be considered in the design of the negative electrode to effectively deal with the adverse effects of its expansion.

Method used

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  • Negative electrode of high-specific energy lithium-ion battery and preparation method of negative electrode

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preparation example Construction

[0024] The present invention also proposes a method for preparing a negative electrode of a high specific energy lithium ion battery, comprising the following steps:

[0025] S1 Add the negative electrode active material, conductive agent 1, conductive agent 2 and binder into deionized water, and fully stir to obtain negative electrode slurry;

[0026] S2 Coat the above-mentioned negative electrode slurry with a coating machine on a copper foil current collector with a thickness of 4-12um, a porosity of 0%-50%, and a pore size of 0-200um, and dry it;

[0027] S3 rolling the copper foil current collector dried in step S2 to make a negative electrode sheet.

[0028] In a specific embodiment of the present invention, the copper foil current collector is one or more of rolled copper foil, electrolytic copper foil, smooth surface foil, and rough surface foil.

[0029] In a specific embodiment of the present invention, the thickness of the copper foil current collector coated with ...

Embodiment 1

[0033] The negative electrode active material is silicon oxygen carbon, the conductive agent 1 and the conductive agent 2 are SP and VGCF, and the binder is CMC and SBR.

[0034] Add appropriate amount of deionized water to silicon oxygen carbon, SP, VGCF, CMC, and SBR according to the mass ratio of 88:3:3:3.5:2.5, and fully stir to prepare slurry. The solid content of the slurry is 35-50%. The viscosity is 4000-6000mPas. Use the coating machine to coat the prepared slurry on the smooth copper foil with a thickness of 8um and a porosity of 0% with a gap of 150um, and dry it. The coated copper foil Roll to a thickness of 60um to make a negative electrode sheet, measure its peeling force, use this electrode sheet to make a 2Ah full battery, the positive electrode matches the ternary positive electrode, and the formula is NCM523:sp:KS-6:PVDF=88:2:2 : 8, the electrolyte is 1MLiPF6inEC / EMC / DEC (1:1:1v / v)+2%VC, and the diaphragm is 25umPP diaphragm. Electrochemical characterization...

Embodiment 2

[0036] The negative electrode active material is silicon oxygen carbon, the conductive agent 1 and the conductive agent 2 are SP and SFG, and the binder is CMC and SBR.

[0037] Add an appropriate amount of deionized water to silocarb, SP, SFG, CMC, and SBR according to the mass ratio of 88:3:3:3.5:2.5, and fully stir to prepare a slurry. The solid content of the slurry is 35-50%. The viscosity is 4000-6000mPas. Use a coating machine to coat the prepared slurry on a smooth copper foil with a thickness of 8um, a porosity of 20%, and a pore diameter of 30um with a gap of 150um, and dry it. The copper foil is rolled to a thickness of 60um to make a negative pole piece, and its peeling force is measured. This pole piece is used to make a 2Ah full battery. The positive electrode matches the ternary positive electrode. The formula is NCM523:sp:KS-6:PVDF=88: 2:2:8, the electrolyte is 1MLiPF6inEC / EMC / DEC (1:1:1v / v)+2%VC, and the diaphragm is 25umPP diaphragm. Electrochemical characte...

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Abstract

The invention relates to a negative electrode of a high-specific energy lithium-ion battery. The negative electrode comprises the following components by mass percent: 70-98% of a negative active material, 0-5% of a conductive agent I, 0-5% of a conductive agent II and the balance of adhesive. Meanwhile, the invention provides a preparation method of the negative electrode of the lithium-ion battery through the components. The method comprises the following steps of (S1) adding the negative active material, the conductive agent I, the conductive agent II and the adhesive to deionized water andfully stirring to obtain negative electrode slurry; (S2) coating a copper foil current collector of which the thickness is 4-12 microns, the porosity is 0-50% and the pore size is 0-200 microns withthe negative electrode slurry by using a coating machine and drying; and (S3) rolling the copper foil current collector dried in the step (S2) to prepare a negative pole piece. The bonding strength ofthe electrode is improved by using combination of different conductive agents and a porous current collector; the adverse effects of volume expansion of a silicon negative electrode in the charging and discharging processes are effectively offset; meanwhile, through the porous design of the current collector, the fold problem of the pole piece caused by expansion of the silicon negative electrodeis solved; and the risk of insecurity of the silicon negative electrode is reduced.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a negative electrode of a high specific energy lithium ion battery and a preparation method thereof. Background technique [0002] With the rapid development of new energy vehicles in recent years and consumers' demand for long mileage, high specific energy lithium-ion power batteries have become an inevitable trend in the development of power batteries. Since high specific energy lithium-ion power batteries need to adopt new battery systems and new processes to provide higher specific energy, therefore, the matching manufacturing process needs to be optimized on the basis of the existing lithium-ion power battery manufacturing process Improvement to improve the safety and electrical performance of high specific energy lithium-ion power batteries, thereby meeting the needs of high-mileage, long-life new energy vehicles. [0003] In terms of negative electrode mater...

Claims

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Application Information

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IPC IPC(8): H01M4/134H01M4/62H01M4/1395H01M10/0525
CPCH01M4/134H01M4/1395H01M4/624H01M10/0525H01M2220/20Y02E60/10
Inventor 孙磊安富强
Owner SHANXI CHANGZHENG POWER TECH CO LTD