Mixed carbon material and negative electrode for nonaqueous rechargeable battery

A carbon material, mixed carbon technology, applied in secondary batteries, non-aqueous electrolyte batteries, battery electrodes, etc., can solve the problems of difficulty in generating air-blocking pores, reduced high-temperature storage characteristics, and reduced storage characteristics, and achieve damage suppression and high-temperature storage. The effect of excellent characteristics and high electrode density

Inactive Publication Date: 2011-08-10
CHUO DENKI KOGYO CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, it becomes difficult to generate gas-blocking pores, and the decrease in charge acceptance is suppressed
However, due to the high hardness of the particles, it is necessary to increase the pressing force required to compress the negative electrode material, and if the negative electrode material cannot be sufficiently compressed due to device reasons, etc., the electrode density cannot be increased.
On the other hand, when excessive compression is performed in order to obtain a high electrode density, the surface coating of the negative electrode material will be significantly damaged, and the high-temperature storage characteristics will be reduced (the capacity of a battery equipped with an electrode using the negative electrode material when stored at a high temperature will decrease) will increase
In addition, since hard particles have insufficient contact between particles, even if the contact resistance between particles after high-temperature storage increases, the storage characteristics will decrease.

Method used

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  • Mixed carbon material and negative electrode for nonaqueous rechargeable battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～5， comparative example 1～3

[0097] The carbon materials A and B obtained by the following production method were mixed according to the compounding ratio (parts by mass) shown in Table 1 to obtain the negative electrode material. In addition, in each of the Examples and Comparative Examples, the compressed densities of the carbon materials A, B, and the mixed carbon materials were measured by the above-mentioned method, and the results are shown in Table 1.

[0098] (1) Carbon material A

[0099] Spheroidized flaky natural graphite powder by solid mixing method using a V mixer. The average particle size is 19.5 μm and the specific surface area (S1) is 5.3 m. 2 100 parts / g of graphite powder and 5 parts of coal-based pitch powder with an average particle size of 35 μm and a softening point of 85° C. were mixed.

[0100] The obtained mixed powder was placed in a heating furnace, under nitrogen flow, heat-treated at 1000° C. for 1 hour, and then allowed to cool to obtain a carbon material with turbostratic...

Embodiment 6

[0104] The carbon materials A and B obtained by the following production method were mixed according to the compounding ratio (parts by mass) shown in Table 1 to obtain the negative electrode material. In addition, the compressed densities of the carbon materials A, B and the mixed carbon materials were measured by the above-mentioned method, and the results are shown in Table 1.

[0105] (1) Carbon material A

[0106] The flake natural graphite powder was spheroidized by solid mixing using a V mixer. The average particle size is 29.5 μm and the specific surface area (S1) is 3.6 m. 2 100 parts of graphite powder per g and 5 parts of coal-based pitch powder with an average particle size of 35 μm and a softening point of 85° C. were mixed.

[0107] The obtained mixed powder was placed in a heating furnace, under nitrogen flow, heat-treated at 1000° C. for 1 hour, and then allowed to cool to obtain a carbon material with turbostratic carbon formed by carbonization of pitch adher...

Embodiment 7

[0111] The carbon materials A and B obtained by the following production method were mixed according to the compounding ratio (parts by mass) shown in Table 1 to obtain the negative electrode material. In addition, the compressed densities of the carbon materials A, B and the mixed carbon materials were measured by the above-mentioned method, and the results are shown in Table 1.

[0112] (1) Carbon material A

[0113] Spheroidized flaky natural graphite powder by solid mixing method using a V mixer. The average particle size is 19.5 μm and the specific surface area (S1) is 5.3 m. 2 100 parts / g of the same graphite powder as in Example 1 and 2 parts of coal-based pitch powder with an average particle diameter of 35 μm and a softening point of 85° C. were mixed.

[0114] The obtained mixed powder was left still in a heating furnace, and was heat-treated at 1000° C. for 1 hour under nitrogen flow, and then allowed to cool to obtain a carbon material with turbostratic carbon for...

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Abstract

A negative electrode material provided by the present invention capable of suppressing a decrease in charge acceptance and high temperature storage properties in an electrode with a high capacity and a high density is a mixed carbon material comprising carbon material A having cores of graphite powder with amorphous carbon and / or turbostratic carbon adhered to or coated on the surface of the cores and carbon material B which is graphite powder, the compressibility which is the density (g / cm 3 ) of the material when 1.00 grams of the material are packed into a cylindrical mold with an inner diameter of 15 mm and compressed by applying a pressing force of 8.7 kN and reducing the pressing force to 0.15 kN is 1.60 - 1.78 g / cm 3 for carbon material A and 1.75 - 1.85 g / cm 3 for carbon material B, the compressibility of carbon material A is less than the compressibility of carbon material B, and the mixing ratio (carbon material A / carbon material B) is 1 - 9 as a mass ratio.

Description

technical field [0001] The present invention relates to a graphite powder-based mixed carbon material suitable for negative electrodes of non-aqueous secondary batteries such as lithium ion secondary batteries, and a negative electrode for non-aqueous secondary batteries in which the carbon material can be used. Background technique [0002] The carbon material constituting the negative electrode of the lithium ion secondary battery is mainly a graphite-based material, and artificial graphite powder can also be used among them. [0003] In order to increase the capacity of lithium-ion secondary batteries, studies have been conducted to increase the capacity per unit mass of graphite-based materials. As a result of this effort, a graphite-based material exhibiting a capacity exceeding 360 mAh / g has now been developed, and the graphite-based material as its own capacity increase almost reaches the limit with respect to the theoretical capacity of graphite of 372 mAh / g. [000...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58C01B31/04H01M4/36
CPCH01M4/133Y02E60/122H01M4/587H01M10/0525C01B31/04C01B32/20C01B32/21Y02E60/10C01B32/00H01M4/583H01M10/05
Inventor 山本浩司永田辰夫藤原彻
Owner CHUO DENKI KOGYO CO LTD
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