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A negative electrode graphite material for lithium-ion secondary battery and preparation method thereof

A secondary battery and lithium-ion technology, applied in battery electrodes, electrode manufacturing, circuits, etc., can solve the problems of insufficient charge capacity release, low charge-discharge efficiency and cycle performance, and achieve high initial charge-discharge efficiency , Improve the appearance and reduce the effect of orientation

Inactive Publication Date: 2007-07-11
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the disadvantages of insufficient discharge of charge capacity, low charge-discharge efficiency and low cycle performance caused by fluffy graphite particles and uneven appearance, so as to provide a graphite with high degree of spheroidization and high initial charging capacity. Discharge efficiency and excellent high-rate charge-discharge and cycle performance of spherical or potato-shaped graphite

Method used

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  • A negative electrode graphite material for lithium-ion secondary battery and preparation method thereof
  • A negative electrode graphite material for lithium-ion secondary battery and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0032]A Φ200 stirred mill is selected as the media mill, and the media balls are chromium steel balls, which are respectively combined in three ratios of Φ6, Φ8, and Φ10 in a ratio of 4:2:1. Take 500g of raw graphite (average particle size: 31.5 μm), and use deionized water as a solvent to prepare a slurry with a solid content of 45%, and add 1% Tween 65 in addition. The filling rate is 60%, the pulp-ball ratio is 1:7 (mass ratio), the rotation speed is 300 rpm, and the stirring treatment time is 60 minutes. Finally, it was taken out, dried, crushed, and classified to obtain spherical graphite with an average particle size of 17.8 μm (as shown in Figure 2).

[0033] Use the graphite as the negative electrode active material to assemble a lithium-ion secondary battery, and use the active material as LiCoO 2 The positive electrode sheet, the electrolyte salt is LiPF 6 , The electrolyte solvent is a mixed organic solvent of ethylene carbonate, ethylene carbonate, and diethyl ca...

Embodiment 2

[0035] A Φ200 stirred mill is selected as the media mill, and the media balls are chromium steel balls, which are respectively combined in three ratios of Φ6, Φ8, and Φ10 in a ratio of 4:2:1. Get 500g of raw graphite (average particle diameter 22.5 μm), the solvent is absolute ethanol, adjust into slurry, solid content 25%, add 0.5% sodium alkyl sulfonate in addition. The filling rate is 50%, the pulp-ball ratio is 1:5 (mass ratio), the rotation speed is 200 rpm, and the stirring treatment time is 40 minutes. Finally, it was taken out, dried, crushed, and classified to obtain spherical graphite with an average particle size of 16.6 μm.

[0036] Use the graphite as the negative electrode active material to assemble a lithium-ion secondary battery, and use the active material as LiCoO 2 The positive electrode sheet, the electrolyte salt is LiPF 6 , The electrolyte solvent is a mixed organic solvent of ethylene carbonate, ethylene carbonate, and diethyl carbonate, the concentra...

Embodiment 3

[0038] A Φ200 stirred mill is selected as the media mill, and the media balls are chromium steel balls, which are respectively combined in three ratios of Φ6, Φ8, and Φ10 in a ratio of 4:2:1. Take 500g of raw graphite (average particle size: 40.5 μm), and use deionized water as a solvent to prepare a slurry with a solid content of 35%, and add 2% Tween 65 in addition. The filling rate is 40%, the pulp-ball ratio is 1:9 (mass ratio), the rotating speed is 400 rpm, and the stirring treatment time is 100 min. Finally, it was taken out, dried, crushed, and classified to obtain spherical graphite with an average particle size of 20.5 μm.

[0039] Use the graphite as the negative electrode active material to assemble a lithium-ion secondary battery, and use the active material as LiCoO 2 The positive electrode sheet, the electrolyte salt is LiPF 6 , The electrolyte solvent is a mixed organic solvent of ethylene carbonate, ethylene carbonate, and diethyl carbonate, the concentratio...

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Abstract

This invention refers to the negative graphite material of lithium ion secondary cell and preparation thereof, said graphite is made from natural scale graphite by mechanical treatment which can disintegrate graphite to the required grain size range and remove the edges and corners to obtain smooth spherical or potato shape graphite grain with greater than 0.2 of sphericity index I110 / I004 obtained by wide angle X ray diffraction. The lithium ion secondary cell using said graphite has as negative active material has high first charge / discharge efficiency, fine high speed charge / discharge and cycle performance.

Description

【Technical field】 [0001] The invention relates to a negative electrode graphite material of a lithium ion secondary battery and a preparation method of the graphite material. 【Background technique】 [0002] Lithium-ion secondary batteries are widely used due to their high voltage, light weight, good safety performance, no memory effect, long cycle life and no environmental pollution. With the development of portable electrical products, people have higher and higher requirements for the batteries used in them, which are mainly reflected in small size, long power consumption time, high-rate charge and discharge performance, and long service life. Especially the power batteries required by electric bicycles, electric vehicles and common electric tools, which have been vigorously developed in the past two years, have high requirements for high-rate charging and discharging performance. [0003] Graphite is the most commonly used negative electrode active material in lithium-io...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58H01M4/04C01B31/04
CPCY02E60/10
Inventor 邹财松董俊卿
Owner BYD CO LTD
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