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Method for producing graphite powder for negative electrode materials for lithium ion secondary batteries

A secondary battery and anode material technology, applied in the direction of secondary batteries, battery electrodes, graphite, etc., can solve the problems of reduced cycle characteristics, lattice defects, high cost, etc., and achieve the effect of high cycle characteristics

Inactive Publication Date: 2018-01-02
SHOWA DENKO KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, since the graphite negative electrode is produced in a block form, a pulverization process is required, the production method is complicated, and the cost becomes high due to pulverization loss.
In addition, there is a problem that lithium ions are irreversibly bonded due to the generation of lattice defects during the pulverization process, and the cycle characteristics are lowered.

Method used

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  • Method for producing graphite powder for negative electrode materials for lithium ion secondary batteries
  • Method for producing graphite powder for negative electrode materials for lithium ion secondary batteries
  • Method for producing graphite powder for negative electrode materials for lithium ion secondary batteries

Examples

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Effect test

Embodiment 1

[0141] The calcined coke was pulverized with a sample pulverizer manufactured by Hosokawa Micron Co., Ltd. (Pantammel AP-B), and then the coarse powder was removed using a sieve with 32 μm openings. Next, airflow classification was performed using a turbo classifier (TC-15N) manufactured by Nisshin Engineering Technology Co., Ltd. to obtain D that does not substantially contain particles with a particle diameter of 1.0 μm or less. 50 = 17 μm powder coke 1 (here, "substantially free" means that particles with a particle size of 1.0 μm or less are 0.1% by mass or less).

[0142] The powder coke 1 and D 50 5μm, D 90 Silicon carbide powder 1 having a size of 9 μm was mixed at a mass ratio of 80:20, and the mixture was heated so that the maximum reached temperature became about 3300° C., thereby performing graphitization treatment. The obtained graphite powder was used to remove coarse powder using a sieve with 45 μm openings (according to JIS Z8801). Measure the yield under the sieve...

Embodiment 2

[0144] In the graphitization process, the raw material silicon carbide mixed with powder coke 1 uses D 50 =13μm, D 90 Except for the silicon carbide powder 2 of 21 μm, the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Embodiment 3

[0146] In the graphitization process, the raw material silicon carbide mixed with powder coke 1 uses D 50 =18μm, D 90 The same procedure as in Example 1 was carried out except for the silicon carbide powder 3 having a thickness of 28 μm. The results are shown in Table 1.

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Abstract

The present invention relates to a method for producing a graphite powder for negative electrode materials for lithium ion secondary batteries. The method is characterized by comprising a step for graphitizing a mixture of a carbon starting material powder and a silicon carbide powder; the 90% particle diameter D90 of the silicon carbide powder in the volume-based cumulative particle size distribution by means of a laser diffraction method is 1-40 [mu]m; the content ratio of silicon carbide in the total mass of the carbon starting material and the silicon carbide, namely (mass of silicon carbide) / (total mass of carbon starting material and silicon carbide), is 1-35% by mass; and the ratio of the 50% particle diameter D50 of the carbon starting material powder to the 50% particle diameter D50 of the silicon carbide powder in the volume-based cumulative particle size distribution by means of a laser diffraction method, namely (D50 of carbon starting material) / (D50 of silicon carbide), is0.40-4.0. A production method of the present invention is able to provide, at a low cost, a graphite powder for negative electrode materials for lithium ion secondary batteries, which has high capacity, high density and a high capacity retention rate.

Description

Technical field [0001] The present invention relates to graphite powder for negative electrode material of lithium ion secondary battery and lithium ion secondary battery. In more detail, the present invention relates to a method for producing graphite powder for a negative electrode material capable of obtaining a lithium ion secondary battery with high capacity, high density, and high capacity retention rate at low cost. Background technique [0002] As a power source for portable devices and the like, lithium ion secondary batteries are mainly used. In recent years, functions such as portable devices have diversified, and power consumption has increased. Therefore, for lithium ion secondary batteries, it is required to increase the battery capacity while improving the charge-discharge cycle characteristics. [0003] In addition, as a power source for electric tools such as electric drills, hybrid vehicles, etc., the demand for high-output and large-capacity secondary batteries...

Claims

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Application Information

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IPC IPC(8): H01M4/587C01B32/205
CPCH01M4/587C01B32/20C01B32/205Y02E60/10H01M10/0525
Inventor 胁坂安显佐藤佳邦宫本大辅
Owner SHOWA DENKO KK