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Positive electrode for lithium secondary battery, and lithium secondary battery using the same

A lithium secondary battery and positive electrode technology, which is applied in the direction of secondary batteries, battery electrodes, non-aqueous electrolyte storage battery electrodes, etc., can solve the problem that the overheating of lithium secondary batteries cannot be greatly suppressed

Active Publication Date: 2007-01-17
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, the present inventors have found through detailed research on lithium secondary batteries that even if the positive electrode for lithium secondary batteries disclosed in Patent Document 1 is used, if the acupuncture test is performed under such severe internal short-circuit conditions, the Cannot significantly suppress overheating of lithium secondary batteries

Method used

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  • Positive electrode for lithium secondary battery, and lithium secondary battery using the same
  • Positive electrode for lithium secondary battery, and lithium secondary battery using the same

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Embodiment approach 1

[0024] The positive electrode for a lithium secondary battery of the present embodiment is a positive electrode for a lithium secondary battery comprising a current collecting base material and a positive electrode coating film having a plurality of mixture layers on the current collecting base material; the positive electrode coating film contains Two or more lithium-containing compounds with different exothermic onset temperatures in the active material; among the two or more lithium-containing compounds, at least one lithium-containing compound has an exothermic onset temperature above 300°C; The first mixture layer closest to the electric base material contains at least one lithium-containing compound having an exothermic onset temperature of 300° C. or higher.

[0025] The positive electrode for a lithium secondary battery of this embodiment will be described with reference to the drawings.

[0026] figure 1 It is a schematic sectional view which shows an example of the ...

Embodiment approach 2

[0062] The positive electrode for a lithium secondary battery according to the present embodiment is a positive electrode in which two or more lithium-containing compounds having different heat generation onset temperatures are contained as positive electrode active materials in the positive electrode coating film formed on the current collecting substrate. ; At least one lithium-containing compound in the two or more lithium-containing compounds has a heat generation onset temperature above 300 ° C; in the thickness direction from the surface layer of the positive electrode coating to the current collector substrate, the heat generation onset temperature is at The content of the lithium-containing compound at 300° C. or higher increases from the surface layer side toward the current collector substrate side.

[0063] The positive electrode for a lithium secondary battery of this embodiment will be described with reference to the drawings. Since the current collecting base mat...

Embodiment

[0076] (i) Preparation of positive electrode active material

[0077] The positive electrode active materials a-1 to a-6 were prepared by the following methods, respectively.

[0078] (i-1)a-1

[0079] Will Li 2 CO 3 and CoCO 3 Mixing at a given molar ratio, calcining at 900°C for 10 hours, pulverizing and classifying, the chemical formula LiCoO 2 Represented positive electrode active material a-1.

[0080] (i-2)a-2

[0081] An aqueous solution containing cobalt sulfate with a concentration of 0.98 mol / liter and magnesium sulfate with a concentration of 0.02 mol / liter is continuously supplied to the reaction tank, and sodium hydroxide is added dropwise to the reaction tank so that the pH of the solution reaches 10 to 13. Synthesize precursors of active substances, wash thoroughly with water and allow to dry. As a result, the Co 0.98 Mg 0.02 (OH) 2 Expressed hydroxide. The precursor was mixed with lithium carbonate so that the molar ratio of lithium, cobalt, and magn...

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Abstract

A positive electrode for use in a lithium secondary battery comprises a positive electrode current collector, and a positive electrode film which is carried on the positive electrode current collector and includes a plurality of mixture layers. The positive electrode film contains, as a positive electrode active material, two or more kinds of lithium-containing compounds having exothermic initiation temperatures different from each other. At least one kind of the two or more kinds of lithium-containing compounds has the exothermic initiation temperature of 300 DEG C or higher. A first mixture layer of the plural mixture layers closest to the positive electrode current collector contains at least one kind of the lithium-containing compound having the exothermic initiation temperature of 300 DEG C or higher. Thereout, it can restrain the overheating of the battery availably in the nailing test, and can provide a positive electrode for use in a lithium secondary battery with a high capability.

Description

technical field [0001] The present invention relates to a high-capacity positive electrode for a lithium secondary battery having excellent reliability as measured by a needle penetration test, and a lithium secondary battery using the positive electrode. Background technique [0002] Lithium secondary batteries are used as operating power sources for notebook computers, portable communication devices, and the like. In recent years, as electronic devices have become more portable or cordless, there has been an increasing demand for higher capacity and smaller and lighter electronic devices. Along with this trend, lithium secondary batteries are gradually increasing in capacity through improvements or changes in electrode materials, improvements in battery structures, and the like. On the other hand, since the energy density is also increased along with the increase in capacity, there is also an extremely high demand for improving the reliability when a large energy is relea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/02H01M4/58H01M4/48H01M10/40H01M4/13H01M4/131H01M4/133H01M4/134H01M4/136H01M4/485H01M4/50H01M4/505H01M4/52H01M4/525H01M10/0525H01M10/0587H01M10/36
CPCH01M4/5825H01M10/0587H01M4/505H01M4/525H01M4/13H01M4/485H01M4/364H01M4/136H01M2300/004H01M4/134Y02T10/7011H01M10/0525H01M4/131Y02E60/122H01M4/133Y02E60/10Y02P70/50H01M4/36H01M4/40Y02T10/70
Inventor 武泽秀治西野肇
Owner PANASONIC CORP
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