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Preparation method of fast charging type lithium ion battery pole piece, pole piece and lithium ion battery

A lithium-ion battery, pole piece technology, applied in electrode manufacturing, battery electrodes, electrode rolling/calendering, etc., can solve the problems of shortened cycle life, low compaction density of single-sided coating area, poor conductivity, etc. Long cycle life, taking into account the effects of energy density and fast charging performance

Inactive Publication Date: 2021-03-30
东莞维科电池有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, since the total thickness of the single-side active material coating plus the current collector foil before rolling is less than the total thickness of the double-side active material coating plus the current collector foil, the pole piece in the single-side coating area passes through the roll gap during rolling. The degree of compaction is small, resulting in a smaller compaction density in the one-sided coated area than in the double-sided coated area
The small degree of pressure will cause two problems: First, the small degree of pressure on the one-side coating area of ​​the pole piece can transmit electrons, but due to the large pores between the particles, if the amount of conductive carbon is not enough, the conductivity of the material itself will be reduced. If the performance is relatively poor, it is difficult to form a good electronic conductive network, that is, the electronic conductivity of the pole piece is low, the problem of lithium precipitation is prone to occur during the battery cycle, the safety performance of the battery cell is reduced, and the cycle life is shortened; Second, the battery pole piece Rolling belongs to powder rolling, and its purpose is to improve the compaction density and uniformity of the active material of the battery pole piece, improve the adhesion of the active material, and improve the surface roughness
The inventors found that the reason is that during the charge-discharge cycle of the battery cell, the negative electrode single-sided coating area is prone to powder drop and lithium precipitation problems, resulting in a decline in the electrical performance of the battery cell.

Method used

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  • Preparation method of fast charging type lithium ion battery pole piece, pole piece and lithium ion battery
  • Preparation method of fast charging type lithium ion battery pole piece, pole piece and lithium ion battery
  • Preparation method of fast charging type lithium ion battery pole piece, pole piece and lithium ion battery

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preparation example Construction

[0035] Such as Figure 1~2 Shown, a kind of preparation method of fast charging type lithium ion battery pole piece comprises the following operations:

[0036] Coating the slurry with the active material on both surfaces of the current collector 1 to obtain a pole piece with a symmetrically arranged first active material layer 2 and a second active material layer 3;

[0037] rolling the two surfaces of the pole piece;

[0038] The redundant first active material layer is cleaned to obtain a fast-charging lithium-ion battery pole piece 4 having a double-side coating area 41 and a single-side coating area 42 .

Embodiment 1

[0040] This embodiment provides a method for preparing a positive electrode sheet of a fast-charging lithium-ion battery, including the following operations:

[0041] (1) Add lithium cobaltate, conductive carbon black (SuperP), carbon nanotubes (CNT) and polyvinylidene fluoride (PVDF) with a particle size D50 of 10 μm to N-methyl In pyrrolidone (NMP), after stirring evenly, positive electrode slurry is obtained;

[0042] (2) The positive electrode slurry is coated on both surfaces of an aluminum foil with a thickness of 10 μm to obtain a positive electrode sheet with a symmetrically arranged first active material layer and a second active material layer; the positive electrode sheet is rolled after drying, and the test surface density is 18.9 mg / cm 2 , the compacted density is 4.15g / cm 3 ;

[0043] (3) Laser burning and cleaning the redundant first active material layer, and cleaning off the coating in this area to obtain a fast-charging lithium-ion battery positive electro...

Embodiment 2

[0045] This embodiment provides a method for preparing a negative electrode sheet of a fast-charging lithium-ion battery, which includes the following operations:

[0046] (1) Graphite, conductive carbon black (SuperP), single-walled carbon nanotubes (SWCNT), sodium hydroxymethylcellulose, and binder (SBR) are used in a mass ratio of 97:0.95:0.05:1:1 Feeding: First, add fast-filling graphite, conductive carbon black (SuperP), single-walled carbon nanotubes (SWCNT), and sodium hydroxymethyl cellulose to an appropriate amount of deionized water, and stir well to form a slurry with a solid content of 46%. 1; Then add the binder (SBR) aqueous solution to the slurry 1, and continue to stir for 0.5 hours to obtain the slurry 2;

[0047] (2) Slurry 2 is coated on the 8 μm thick negative electrode current collector copper foil, obtains the negative electrode sheet that has the first active material layer and the second active material layer that are arranged symmetrically, and the tes...

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Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method of a fast charging type lithium ion battery pole piece. The method comprises thefollowing steps of coating slurry with active substances on the two surfaces of a current collector to obtain the pole piece with a first active substance layer and a second active substance layer which are symmetrically arranged; rolling the two surfaces of the pole piece; and cleaning the redundant first active material layer to obtain the fast charging type lithium ion battery pole piece witha double-sided coating area and a single-sided coating area. According to the preparation method of the fast charging type lithium ion battery pole piece, the rolling thickness of the single-side coating area of the pole piece after rolling is consistent with that of the double-side coating area, and the compression degree of active substance layers at the two sides of the pole piece can be effectively ensured to be consistent during rolling; and the failure problems of powder falling, lithium precipitation and the like of the single-side coating area in the subsequent charging and dischargingprocess due to different thicknesses of the single-side coating area and the double-side coating area of the pole piece and different compression degrees when the pole piece is rolled to pass througha roll gap in the traditional process, are effectively avoided.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a preparation method of a pole piece of a fast-charging lithium-ion battery, a pole piece and a lithium-ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long cycle life, and good safety performance. With the gradual increase of the lithium-ion battery market, consumers have higher and higher requirements for the fast charging performance and energy density of lithium-ion batteries. Therefore, the development of lithium-ion batteries with high energy density and fast charging capability has always been the direction of research and development personnel's attention. [0003] The electrical performance of lithium-ion batteries depends to a large extent on the structure and performance of the pole piece. To improve this performance, the current common method in the industry is to optimize the posi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/139H01M4/04H01M4/13H01M10/0525
CPCH01M4/0404H01M4/0435H01M4/13H01M4/139H01M10/0525Y02E60/10
Inventor 杜红梁晓静夏小勇
Owner 东莞维科电池有限公司
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