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Negative electrode for nonaqueous electrolyte secondary battery, method for producing same, and nonaqueous electrolyte secondary battery

A non-aqueous electrolyte and secondary battery technology, which is applied in the direction of battery electrodes, negative electrodes, active material electrodes, etc., can solve the problems of decreased discharge capacity, diffusion failure, and difficulty in deintercalation of lithium ions, so as to suppress the disorder of orientation and improve Effect of Large Current Characteristics

Inactive Publication Date: 2012-05-30
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When charging, lithium ions are inserted into the negative electrode mixture layer from the direction perpendicular to the surface of the current collector, so if the graphite layer is oriented in a direction parallel to the surface of the current collector, lithium ions cannot be efficiently removed from the edges of each layer of graphite. partially intercalated lithium ions
In addition, it is difficult for lithium ions to deintercalate smoothly during discharge.
In particular, when charging and discharging with a large current, the diffusion of lithium ions in the negative electrode mixture layer cannot catch up, so the discharge capacity decreases.

Method used

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  • Negative electrode for nonaqueous electrolyte secondary battery, method for producing same, and nonaqueous electrolyte secondary battery
  • Negative electrode for nonaqueous electrolyte secondary battery, method for producing same, and nonaqueous electrolyte secondary battery
  • Negative electrode for nonaqueous electrolyte secondary battery, method for producing same, and nonaqueous electrolyte secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0110] (1) Production of positive electrode

[0111] Contains lithium nickelate (LiNiO 2 ), an appropriate amount of NMP is added to the mixture of acetylene black as a conductive material and polyvinylidene fluoride (PVDF) as a binder. The obtained mixture was kneaded with a planetary mixer to obtain a slurry-like positive electrode mixture (positive electrode slurry).

[0112] The positive electrode slurry was coated on both surfaces of a positive electrode current collector made of aluminum foil (thickness 15 μm, width 100 mm), and air-dried at 80° C. for 20 minutes. The obtained positive electrode current collector having the coating film was rolled with a roll at a linear pressure of 2000 kgf / cm (19.6 kN / cm). Thus, the positive electrode 5 in which the positive electrode mixture layers were formed on both surfaces of the positive electrode current collector was obtained. The thickness of the positive electrode mixture layer was 40 μm, and the thickness of the positive ...

Embodiment 2

[0128] A negative electrode was fabricated in the same manner as in Example 1 except that the linear pressure during rolling was 100 kgf / cm (980 N / cm). The density of the negative electrode mixture layer is 1.2g / cm 3 . Using the obtained negative electrode, a battery A2 was obtained in the same manner as in Example 1.

Embodiment 3

[0130] A negative electrode was produced in the same manner as in Example 1 except that the number of times of rolling was changed to two. The density of the negative electrode mixture layer is 1.6g / cm 3 . Using the obtained negative electrode, a battery A3 was obtained in the same manner as in Example 1.

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Abstract

Disclosed is a negative electrode which is capable of improving large current characteristics, while maintaining the battery capacity of a nonaqueous electrolyte secondary battery. Specifically disclosed is a negative electrode for a nonaqueous electrolyte secondary battery, which comprises a sheet-like negative electrode collector and a negative electrode mixture layer that is arranged on the surface of the negative electrode collector. The negative electrode mixture layer contains graphite particles and ceramic particles that intervene among the graphite particles. The average particle diameter of the ceramic particles is smaller than the average particle diameter of the graphite particles. In the x-ray diffraction pattern of the negative electrode mixture layer, the ratio (R) of the intensity (I110) of a peak ascribed to the (110) plane of the graphite particles to the intensity (I002) of a peak ascribed to the (002) plane of the graphite particles, namely I110 / I002 is not less than 0.05. The negative electrode mixture layer has a density of 1.1-1.8 g / cm3.

Description

technical field [0001] The invention relates to a negative electrode for a non-aqueous electrolyte secondary battery, in particular to the improvement of a negative electrode mixture layer containing graphite as a negative electrode active material. Background technique [0002] In recent years, portable and cordless electronic devices are rapidly progressing, and there is an increasing demand for small, lightweight secondary batteries with high energy density as power sources for driving such devices. In addition, not only in small consumer applications, but also in large secondary batteries for power storage devices and electric vehicles, high output characteristics, long-term durability, and safety are required. [0003] On the other hand, a non-aqueous electrolyte secondary battery has a negative electrode in which a material mixture layer containing a negative electrode active material is arranged on a negative electrode collector, and a material mixture layer containin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/133H01M4/1393H01M4/36H01M4/485H01M4/587H01M4/62
CPCY02E60/12H01M2004/027H01M4/133Y02E60/122H01M4/1393H01M4/587H01M2004/021H01M4/364H01M4/485Y02E60/10
Inventor 天明裕永山雅敏
Owner PANASONIC CORP
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