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Active substance for use in negative electrode of lithium ion secondary battery, and negative electrode of lithium ion secondary battery and lithium ion secondary battery using same

A secondary battery and active material technology, which is applied in secondary batteries, battery electrodes, non-aqueous electrolyte storage batteries, etc., can solve the problems of increasing the volume density of electrodes containing active materials, and achieve the effect of excellent performance balance and increased volume density

Inactive Publication Date: 2015-05-06
NIPPON STEEL CHEMICAL CO LTD
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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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  • Active substance for use in negative electrode of lithium ion secondary battery, and negative electrode of lithium ion secondary battery and lithium ion secondary battery using same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Lump coke (green coke) produced by heat treatment at 500°C for 24 hours is obtained by delayed coking using refined pitch from coal-based heavy oil from which quinoline-insoluble components have been removed, and finely pulverized by an Orient mill and a jet mill. , to get the average particle size (D 50 ) is a 11.9 μm green coke sheet (finely pulverized green coke).

[0051] The lump-like green coke obtained above was heat-treated in a rotary kiln at a temperature ranging from 700° C. near the inlet to 1500° C. near the outlet (the highest reaching temperature) for 1 hour or more to obtain lump-shaped calcined coke. This calcined coke is finely pulverized by a jet mill by appropriately adjusting the treatment amount per unit time and the gas flow rate during treatment in the same manner as above, and then most of the fine powders below 3 μm are removed by air classification, thereby obtaining true coke. The specific gravity is 2.14g / cm 3 、D 10 5.3μm, D 50 11.5μm, D...

Embodiment 2 and 3、 comparative example 1 and 2

[0055] 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 materials for lithium ion secondary batteries with different particle size distributions shown in Table 1 were obtained. Table 1 shows the properties of the obtained powder. In addition, as a result of observing the cross-section of the fabricated electrode, it was confirmed that 85 to 89% of the active material particles corresponded to the ellipse in which the aspect ratio was in the range of 0.05 to 0.70 was 85 to 89%. Using these, a negative electrode electrode and a lithium ion secondary battery were obtained, and charging characteristics were investigated. The results are shown in Table 1.

Embodiment 4

[0057] The bulk green coke is heat-treated by a rotary kiln at a temperature near the inlet of 700°C to a temperature near the outlet of 1000°C (the highest reaching temperature) for more than 1 hour to obtain a lump of calcined coke. The same operation was performed to obtain a lithium secondary battery. Table 1 shows the properties of the obtained powder. As a result of observing the cross section of the produced electrode, it was confirmed that 90% of the active material particles corresponded to the range of the aspect ratio of the ellipse in the range of 0.05 to 0.70. In addition, charging characteristics were investigated in the same manner as in Example 1. The results are shown in Table 1.

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Abstract

Provided are: an active substance for use in the negative electrode of a lithium ion secondary battery that has a high capacity per unit volume (weight) and that possesses practical characteristics related to the discharge capacity, initial efficiency, input characteristics, capacity retention rate, and the like of a lithium ion secondary battery that make it possible for said active substance to be used in vehicles such as HEVs and PHEVs; and a negative electrode of a lithium ion secondary battery and a lithium ion secondary battery using said active substance. The active substance for use in the negative electrode of a lithium ion secondary battery: is formed from a carbon material having a true specific gravity of 2.00-2.16 g / cm3; has a volume-based particle size distribution that is within a range in which D10 is 3-9 µm, D50 is 10-20 µm, D90 is 21-40 µm, and D90-D10 is 15-35 µm; and has a tap density of 0.8 g / cc or higher. The lithium ion secondary battery comprises: a negative electrode comprising a composite layer formed by mixing the active substance for use in the negative electrode of a lithium ion secondary battery with a binder on a current collector; and a separator via which the negative electrode and a positive electrode are arranged to face each other.

Description

technical field [0001] The invention relates to an active material for a negative electrode of a lithium ion secondary battery, a negative electrode of a lithium ion secondary battery and a lithium ion secondary battery using the active material. 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 nickel-metal hydride battery-driven engine and a gasoline engine, and mobile electronic devices such as camcorders. It is expected that the demand will increase in the f...

Claims

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Application Information

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IPC IPC(8): H01M4/587H01M4/133
CPCH01M4/133H01M4/583H01M10/0525H01M10/058H01M4/1393H01M4/587H01M2004/021Y02E60/10
Inventor 服部公一小关和德谷口大辅
Owner NIPPON STEEL CHEMICAL CO LTD
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