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Pole piece and preparation method thereof and application of pole piece in battery

A pole piece, conductive agent technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of decreased utilization of electrode active materials, limited lithium ion diffusion kinetics, damaged battery energy density, etc. The effect of increasing rate performance and cycle stability, reducing labor costs, and improving cycle stability

Pending Publication Date: 2020-08-11
EVE ENERGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As the thickness of the pole piece increases, the specific energy of the battery increases correspondingly at lower rates; however, at higher rates, the diffusion kinetics of lithium ions is limited, the utilization rate of electrode active materials decreases, and the energy density of the battery is impaired.

Method used

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  • Pole piece and preparation method thereof and application of pole piece in battery
  • Pole piece and preparation method thereof and application of pole piece in battery
  • Pole piece and preparation method thereof and application of pole piece in battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0116] A kind of preparation of negative pole sheet:

[0117] (1) Preparation of the first electrode slurry with a viscosity of 4000mPa·s and a solid content of 52wt%:

[0118] (a) Mix the first thickener (CMC2200) and the first solvent (water) to obtain the mixed material 1;

[0119] (b) mixing the first active material (artificial graphite) and the first conductive agent (Li435) to obtain a mixed material 2;

[0120] (c) stirring and mixing the mixed material 2 and part of the mixed material 1, the stirring speed is 2500 rpm, and the stirring time is 60 min, to obtain the mixed material 3, the solid content of the mixed material 3 is 65wt%;

[0121] (d) mixing the remaining mixed material 1 with mixed material 3 to obtain mixed material 4;

[0122] (e) Stir and mix the mixed material 4 and the first binder (SBR451B), the stirring rate is 1500rpm, and the stirring time is 60min to obtain the first electrode slurry, which is carried out by using a 150-mesh stainless steel me...

Embodiment 2

[0134] The difference from Example 1 is that the first conductive agent in step (b) is SP, that is, the first conductive agent is the same as the second conductive agent.

Embodiment 3

[0136] The difference with Example 1 is that, in the first electrode slurry described in step (1), the content of the first conductive agent is 1.1wt%; in the second electrode slurry described in step (2), the content of the second conductive agent The content is 0.9wt% (the total amount of the conductive agent in the overall pole piece remains unchanged, and the increase or decrease of the conductive agent in the slurry is equally shared by other components).

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Abstract

The invention relates to a pole piece and a preparation method thereof and an application of the pole piece in a battery. The mass content of the conductive agent in the first active material layer iscontrolled to be greater than the mass content of the conductive agent in the second active material layer; the concentration of the conductive agent in the pole piece is in longitudinal gradient distribution, so that the content of the conductive agent in the lower active material layer close to the current collector is high, more conductive paths can be formed due to the high content of the lower conductive agent, the electron transmission resistance of the pole piece is low, and the rate performance and the cycling stability of the battery are improved. A double-cavity die head coating machine is used for coating two kinds of slurry at the same time, the problem that the occupied space is large due to the fact that two coating machines are used for coating at the same time is solved, meanwhile, the double-cavity die head coating machine can be operated by only one person, and the labor cost is reduced; moreover, two kinds of slurry are coated at the same time, so that the problem of poor compatibility between layers caused by separate coating (drying after bottom layer coating and top layer coating again) in the prior art is solved.

Description

technical field [0001] The invention belongs to the technical field of battery preparation, and in particular relates to a pole piece, its preparation method and its application in batteries. Background technique [0002] At present, in order to solve the mileage problem of electric vehicles, improving energy density is an important direction for the development of lithium-ion batteries. The most direct way to increase the specific energy of the battery is to prepare an ultra-thick pole piece with a high coating amount, which can effectively reduce the proportion of inactive materials, such as current collectors, tabs, and battery casings. As the thickness of the pole piece increases, the specific energy of the battery increases correspondingly at lower rates; however, at higher rates, the diffusion kinetics of lithium ions is limited, the utilization rate of electrode active materials decreases, and the energy density of the battery is impaired. Therefore, for thick electr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/133H01M4/1393H01M4/36H01M4/587H01M4/62H01M10/0525
CPCH01M4/362H01M4/587H01M4/621H01M4/625H01M4/133H01M4/1393H01M10/0525Y02E60/10
Inventor 赵仕绪杜双龙殷军伍山松方杰雄吕正中刘金成
Owner EVE ENERGY CO LTD
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