Negative electrode active material for lithium ion secondary battery, negative electrode for lithium ion secondary battery using the same, and lithium ion secondary battery

A negative electrode active material, secondary battery technology, applied in secondary batteries, battery electrodes, circuits, etc., can solve the problem of increasing the volume density of electrodes containing active materials, and achieve the effect of excellent performance balance and improved volume density.

Inactive Publication Date: 2015-09-16
NIPPON MICROMETAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, in raw cokes such as coal series and calcined cokes such as coal series, there are problems such as an increase in the capacity of the active material contained in it and an increase in the bulk density at the time of the electrode.

Method used

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  • Negative electrode active material for lithium ion secondary battery, negative electrode for lithium ion secondary battery using the same, and lithium ion secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] Lump coke (green coke) produced by delayed coking method using refined pitch from coal-based heavy oil from which quinoline insoluble components have been removed and heat-treated at 500°C for 24 hours is performed by orient mill and jet mill Finely pulverize to obtain the average particle size (D 50 ) is a green coke sheet (finely pulverized green coke) of 10.5 μm.

[0056] The green coke pieces obtained as described above were calcined in a low-oxygen atmosphere from 700° C. near the inlet to 1500° C. near the outlet (the highest reaching temperature) for more than one hour in a rotary kiln to obtain calcined coke. The calcined coke is finely pulverized using the same jet mill as above, and the processing amount per unit time and the gas flow rate during processing are appropriately adjusted, and then most of the fine powder below 3 μm is removed by air classification, thereby obtaining the true specific gravity. 2.15g / cm 3 、D 10 3.7μm, D 50 10.2μm, D 90 19.7μm, ...

Embodiment 2～3、 comparative example 1～3

[0063] Except changing the conditions at the time of jet mill pulverization after obtaining calcined coke, the same operation as Example 1 was performed respectively, and the negative electrode active material for lithium ion secondary batteries which differs in particle size distribution as shown in Table 1 was obtained. Table 1 shows the characteristics of the obtained negative electrode active material. In addition, as a result of observing the cross-section of the electrode prepared in the same manner as in Example 1, it was confirmed that the active material particles corresponding to the ellipse with an aspect ratio in the range of 0.05 to 0.70 were 85 to 89% in all samples. Using these particles, a negative electrode and a lithium ion secondary battery were obtained in the same manner as in Example 1, and the charge retention ratio was investigated for each. The results are shown in Table 1.

Embodiment 4

[0065] Using a rotary kiln, calcined green coke pieces in a low-oxygen atmosphere from a temperature near the inlet of 700°C to a temperature near the outlet of 1000°C (the highest temperature) for more than 1 hour to obtain calcined coke. 1 The same operation was performed to obtain a lithium-ion secondary battery. Table 1 shows the characteristics of the obtained negative electrode active material. In addition, as a result of observing the cross-section of the electrode produced in the same manner as in Example 1, it was confirmed that 90% of the active material particles corresponded to an ellipse having an aspect ratio in the range of 0.05 to 0.70. In addition, the charge maintenance rate and initial efficiency were investigated in the same manner as in Example 1. The results are shown in Table 1.

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Abstract

The invention provides a negative electrode active material for a lithium ion secondary battery, a negative electrode for a lithium ion secondary battery using the same, and a lithium ion secondary battery. The negative electrode active material possesses the practical features of realizing HEV and PHE vehicle purposes as the discharge capacity, initial efficiency, input characteristics and capacity retention of a lithium ion secondary battery, and the capacity of each unit volume (weight) s high. The negative electrode active material for a lithium ion secondary battery is prepared by carbon materials with the true specific gravity of 2.00-2.16 g / cm3; in the grain fineness distribution of grains based on a volume basis, D10 is in a range of 2-5 mum, D50 is in a range of 8-12 mum, D90 is in a range of 16-26 mum, and D50 is in a range of 5-10 mum, and a tap density is above 0.4g / cc; a BET specific area employing the nitrogen adsorption flowing method is 5.1-9.0 m2 / g.

Description

technical field [0001] The invention relates to a negative pole active material for a lithium ion secondary battery, a lithium ion secondary battery negative pole and a lithium ion secondary battery using the same. Background technique [0002] Lithium-ion secondary batteries are widely used instead of nickel-cadmium batteries and nickel-metal hydride batteries, which have been the mainstream in the past, in view of their excellent characteristics such as high operating potential, large battery capacity, and long cycle life, and less environmental pollution. . [0003] In addition, in order to cope with energy problems and environmental problems, it is widely used as a power source for electric vehicles, hybrid electric vehicles (HEV: Hybrid Electric Assistant) that combine a motor driven by a nickel-metal hydride battery and a gasoline engine, and mobile electronic devices such as camcorders. It is expected that the demand will increase in the future. [0004] As a negati...

Claims

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Application Information

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IPC IPC(8): H01M4/587H01M4/133H01M10/0525C01B31/00
CPCC01B32/00C01P2004/61H01M4/133H01M4/587H01M10/0525H01M2004/021Y02E60/10
Inventor 服部公一小关和徳谷口大辅
Owner NIPPON MICROMETAL
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