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Artificial graphite material for lithium ion secondary battery negative electrode, and method for producing same

一种二次电池、人造石墨的技术，应用在电极制造、二次电池、电池电极等方向，能够解决降低高度可靠性的要求、无法使用边缘面率、电池内部电阻变高等问题，达到降低内部电阻、抑制容量劣化的效果

Active Publication Date: 2016-11-02
JX NIPPON OIL & ENERGY CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The coating film of the reaction product becomes a resistance component in the reversible intercalation reaction of lithium ions, so the growth of the coating film leads to an increase in the internal resistance of the battery
In particular, a coating film is easily formed and grown on the edge face of the hexagonal grid planar laminate on the surface of the graphite material, which is the entrance and exit of lithium ions. Therefore, there is a problem that as the charge-discharge cycle progresses, the battery's internal The resistance increases, and the apparent battery capacity obtained under the specified current also decreases as the cycle progresses
Therefore, it is difficult to simultaneously satisfy both the demand for reduction of internal resistance and the demand for high reliability
The reason is that in order to ensure high reliability, it is necessary to use a graphite material with a low edge area ratio for the negative electrode. On the other hand, in order to meet the requirements for reducing the internal resistance, it is not possible to use a graphite material with a small edge area ratio for the negative electrode.
As mentioned above, the edge surface existing on the surface of the graphite material is the entrance and exit of lithium ions that are stored or released along with charging and discharging. Therefore, when a graphite material with a low edge surface area ratio, that is, a few entrances and exits, is used as the negative electrode, The internal resistance of the battery tends to become high

Method used

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  • Artificial graphite material for lithium ion secondary battery negative electrode, and method for producing same
  • Artificial graphite material for lithium ion secondary battery negative electrode, and method for producing same
  • Artificial graphite material for lithium ion secondary battery negative electrode, and method for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0128] The raw coke A was pulverized with a mechanical pulverizer (super rotary pulverizer / manufactured by Nissin Engineering), and classified with a precision air classifier (vortex classifier / manufactured by Nissin Engineering), thereby obtaining an average particle size Green coke powder with a diameter of 12 μm. The average particle diameter of the green coke powder was measured using laser diffraction / scattering type particle size distribution analyzer LA950 manufactured by Horiba Seisakusho. The powder was put into a graphite crucible, set in an induction heating graphitization furnace, and graphitized at a maximum temperature of 2900° C. in a nitrogen gas flow of 80 L / min. At this time, the temperature rise rate is 200°C / hour, the holding time of the highest temperature is 3 hours, the temperature drop rate is 100°C / hour until it drops to 1000°C, and then naturally cool to room temperature while maintaining the nitrogen flow to obtain a graphite material.

Embodiment 2

[0130] Green coke B was pulverized, classified and graphitized by the method described in Example 1 to obtain a graphite material.

Embodiment 3

[0132] Green coke C was pulverized, classified and graphitized by the method described in Example 1 to obtain a graphite material.

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Abstract

The present invention relates to an artificial graphite material with which capacity degradation accompanying charge / discharge cycles can be suppressed and internal resistance reduced, said graphite material being used in the negative electrode of a lithium ion secondary battery having high output characteristics. Provided is an artificial graphite material for a lithium ion secondary battery negative electrode, said graphite material having a crystallite size (L (112)) of 5-25 nm in a c-axis direction, a peak strength ratio (ID / IG) of 0.05-0.2, and a relative absorption intensity ratio (I4.8K / I280K) of 5.0-12.0.

Description

technical field [0001] The present invention relates to graphite materials used as negative electrodes for lithium-ion secondary batteries. Background technique [0002] Lithium-ion secondary batteries are lighter in weight and have higher input and output characteristics than conventional secondary batteries such as nickel-cadmium batteries, nickel-hydrogen batteries, and lead batteries. Therefore, it has been practically used as a power source for electric vehicles and hybrid vehicles. In general, a lithium ion secondary battery has a positive electrode and a negative electrode facing each other through a non-aqueous electrolyte, wherein the positive electrode contains lithium capable of reversible intercalation of lithium, and the negative electrode contains a carbon material. Therefore, the lithium ion secondary battery is assembled in a discharged state, and must be charged to become a dischargeable state. In the following, lithium cobalt oxide (LiCoO 2 ), the negati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/587C01B31/04
CPCH01M4/587H01M10/052C01P2002/90C10B57/045C01B32/20C01B32/205Y02E60/10H01M4/133H01M10/0525C01P2002/77C01P2002/82C01P2002/86C01P2006/40H01M2004/027H01M4/0471
Inventor 铃木贵志藤井政喜前田崇志川地浩史
Owner JX NIPPON OIL & ENERGY CORP
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