Modified natural graphite particles

A technology of natural graphite and particles, applied in the direction of graphite, structural parts, electrical components, etc., can solve the problems of falling off of negative electrode mixture, decrease of bonding strength between negative electrode active material and current collector, etc.

Inactive Publication Date: 2014-02-19
CHUO DENKI KOGYO CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] In the negative electrode mixture used in the manufacture of the negative plate of the non-aqueous electrolyte secondary battery, if only reducing the amount of binder, the following problems will occur: between the negative electrode active materials, or the bonding between the negative electrode active materials and the current collector The strength is reduced, and the negative electrode mixture falls off from the current collector or the negative electrode plate during the manufacturing process of the negative plate and the assembly operation of the battery

Method used

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  • Modified natural graphite particles
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～4 and comparative example 1～4

[0127] (1) Manufacture of modified natural graphite particles

[0128] For raw material natural graphite particles (flaky graphite produced in China, the absolute specific gravity is 2.26g / cm 3 ), the spheroidization process was performed using a pulverization device (ACM pulverizer, ACM-10A) manufactured by HOSOKAWA MICRON CORPORATION. Repeat treatment 15 times. Then the fine powder is removed by wind classification. The spheroidization treatment was carried out at appropriately different grinding rotation speeds and classification rotation speeds to obtain four types of spheroidized graphite particles having different particle sizes as shown in Comparative Examples 1 to 4 in Table 1.

[0129] With respect to these graphite particles, a portion of each was further subjected to smoothing treatment using a Mechano Fusion system (AMS-Lab) manufactured by HOSOKAWA MICRON CORPORATION. The processing conditions are as follows.

[0130] Input amount: 600g

[0131] Gap between r...

Embodiment 5 and comparative example 5

[0167] Coal-based pitch powder with an average particle diameter of 15 μm was mixed with the graphite particles obtained in Example 2 and Comparative Example 2 in an amount of 20% by mass relative to the graphite particles, and the mixture was subjected to nitrogen flow at 1000° C. for 1 hour. After heat treatment, carbon-attached graphite particles with turbostratic carbon attached to the surface are obtained. The average particle diameter, specific surface area, tap density, and linseed oil absorption of the obtained carbon-attached graphite particles were determined in the same manner as in Examples 1 to 4. The results are shown in Table 2.

[0168] The anode active material containing the thus obtained carbon-attached graphite particles and PVdF were mixed at a mass ratio of 95:5 to prepare an anode mixture. Using these negative electrode mixtures, negative electrode plates were prepared in the same manner as in Examples 1-4. The results of measuring the peel strength of...

Embodiment 6 and comparative example 6

[0173] Coal-based pitch powder with an average particle size of 15 μm was mixed with the graphite particles obtained in Example 3 and Comparative Example 3 in an amount of 2% by mass relative to the graphite particles, and heat-treated at 1000° C. for 1 hour in a nitrogen stream. , to obtain carbon-attached graphite particles with turbostratic carbon attached to the surface. The average particle diameter, specific surface area, tap density, and linseed oil absorption of the obtained carbon-attached graphite particles were determined in the same manner as in Examples 1 to 4. The results are shown in Table 3.

[0174] A negative electrode mixture was prepared by mixing the negative electrode active material containing the thus obtained carbon-attached graphite particles, SBR, and CMC at a mass ratio of 98:1:1. Using these negative electrode mixtures, negative electrode plates were prepared in the same manner as in Examples 1-4. The results of measuring the peel strength of the...

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Abstract

A modified natural graphite material that provides a negative electrode plate with excellent adhesion between a negative electrode composite material and a current collector has a circularity of 0.92-1.0, and the incidence angle dependency S60 / 0 of the peak intensity ratio obtained from the C-K end X-ray absorption spectrum of a powder measured using the emitted light as an excitation light source is 0.5-0.7. Preferably at least one of the following conditions is satisfied: absolute specific gravity is 2.25 g / cm3 or higher, tap density is 1.0-1.4 g / cm3, and the linseed oil absorption is 20-50 cm3 / 100 g. A carbonaceous material may be adhered to at least a portion of the surface thereof.

Description

technical field [0001] The present invention relates to modified natural graphite particles useful as a negative electrode active material in a negative electrode plate of a nonaqueous electrolyte secondary battery, particularly a lithium ion secondary battery. Background technique [0002] The negative electrode plate of the non-aqueous electrolyte secondary battery represented by the lithium ion secondary battery is manufactured by the method comprising the following steps: the negative electrode mixture formed by mixing at least the negative electrode active material and the binder is coated on the current collector Then compact it. Most current collectors are foils made of copper or copper alloys. [0003] The negative electrode active material uses a material that can store cations such as lithium ions during charging, and a typical material includes a graphite material that has a layered crystal structure and can store cations between layers. Graphite materials are b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04H01M4/36H01M4/587
CPCH01M4/1393C01P2006/11C01P2006/19H01M4/625H01M4/366H01M4/587C01P2006/10H01M4/663H01M10/052Y02E60/122C01B31/04H01M4/133C01B32/21Y02E60/10H01M10/0525C01P2002/74C01P2006/90
Inventor 西原克浩山本浩司永田辰夫祢宜教之藤原彻
Owner CHUO DENKI KOGYO CO LTD
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