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Lithium secondary battery

A conductive technology for lithium secondary batteries and negative electrodes, which is applied in the direction of secondary batteries, lithium batteries, battery electrodes, etc., can solve the problems of not being able to fully improve the initial charge and discharge efficiency, and achieve the effect of high adhesion and high current collection

Inactive Publication Date: 2007-03-14
SANYO ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, even in lithium secondary batteries using this method, the initial charge-discharge efficiency cannot be sufficiently improved, and further improvement in cycle characteristics is desired.
So there is still room for improvement

Method used

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Examples

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Comparison scheme
Effect test

Embodiment 1

[0110] As Example 1, the lithium secondary battery shown in the best mode for carrying out the invention was used.

[0111] Hereinafter, the battery produced in this way is referred to as battery A1 of the present invention.

Embodiment 2、3

[0113] Lithium secondary batteries were produced in the same manner as in Example 1, except that the particle diameters (before charging) of Si powder used as the negative electrode active material were 7.5 μm and 10.0 μm, respectively.

[0114] Hereinafter, the batteries produced in this way are referred to as batteries A2 and A3 of the present invention, respectively.

Embodiment 1～4

[0138] Except that the particle size of graphite used as negative electrode conductor is 3.4 μm (BET specific surface area is 12.5m 2 / g), 3.7μm (BET specific surface area is 14.2m 2 / g), 5.3μm (BET specific surface area is 10.5m 2 / g), 12.0μm (BET specific surface area is 7.7m 2 / g), a lithium secondary battery was produced in the same manner as in Example 1 of the first example.

[0139] Hereinafter, the batteries produced in this way are respectively referred to as batteries B1 to B4 of the present invention.

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Abstract

A lithium secondary battery has a positive electrode, a negative electrode, and a non-aqueous electrolyte. The negative electrode has a negative electrode current collector and a negative electrode mixture layer containing a negative electrode conductive agent, a negative electrode binder, and negative electrode active material particles made of a material containing silicon. The negative electrode mixture layer is sintered and disposed on the negative electrode current collector. The negative electrode active material particles have an average particle size of from 5.0 to 15.0 mu m before being charged. The negative electrode conductive agent is made of a graphite material having an average particle size of from 2.5 to 15.0 mu m. The amount of the graphite material added is from 3 to 20% by mass with respect to the negative electrode active material. The theoretical electrical capacity ratio of the positive electrode to the negative electrode is 1.0 or less.

Description

technical field [0001] The present invention relates to a lithium secondary battery using a material containing silicon as a negative electrode active material. Background technique [0002] In recent years, the size and weight of mobile information terminals such as mobile phones, notebook PCs, and PDAs has rapidly increased, and further increases in capacity have been demanded for batteries as their driving power sources. Lithium secondary batteries, which are charged and discharged by moving lithium ions between positive and negative electrodes along with charging and discharging, have high energy density and high capacity, and are therefore widely used as driving power sources for mobile information terminals as described above. In the future, with the further miniaturization and higher functionality of these mobile information terminals, it is expected that the load on the lithium secondary battery as a power source will continue to increase, and the demand for higher e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/02H01M4/62H01M4/38H01M4/134H01M4/1395H01M10/05H01M10/052H01M10/058
CPCH01M2010/4292H01M4/625H01M2004/027H01M2004/021H01M4/1395H01M4/38H01M4/622H01M10/446H01M4/02H01M4/0471Y02E60/122H01M4/386Y02E60/10Y02P70/50H01M4/583H01M10/058
Inventor 福井厚史南博之樟本靖幸
Owner SANYO ELECTRIC CO LTD