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Lithium secondary battery

A lithium secondary battery and battery casing technology, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of battery overheating, Joule heat, expansion, etc., and achieve excellent short-circuit resistance and heat resistance.

Active Publication Date: 2007-10-24
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Once an internal short circuit occurs, the short circuit will expand due to the Joule heat generated by the short circuit current, resulting in overheating of the battery

Method used

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Examples

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Embodiment 1

[0066] In this embodiment, the cylindrical lithium secondary battery shown in FIG. 1 is explained.

[0067] (Battery 1)

[0068] (i) Preparation of positive electrode

[0069] Using a double-arm kneader, 3 kg of lithium cobaltate, 1 kg of PVDF#1320 (N-methyl-2-pyrrolidone (hereinafter referred to as NMP) solution containing 12 wt % PVDF), 90 g of Kureha Chemical Industry Co., Ltd. Acetylene black and an appropriate amount of NMP were stirred to prepare a positive electrode mixture slurry. The resulting slurry was coated on both sides of a positive electrode core member comprising a 15 μm thick aluminum foil, dried and rolled to form a positive electrode with a positive electrode active material layer. The total thickness of the positive electrode was 160 μm. The positive electrode was cut into strips with a width of 56.5 mm.

[0070] (ii) Preparation of negative electrode

[0071] Using a double-arm kneader, the BM-400B (water dispersion containing 40wt% modified styrene-...

Embodiment 2

[0172] In this embodiment, the prismatic lithium secondary battery shown in FIG. 2 is explained.

[0173] (battery 31)

[0174] An electrode assembly was produced in the same manufacturing method as in Example 1 except for the following differences. The total thickness of the positive electrode becomes 150 μm, and the width of the positive electrode becomes 42.7 mm. The total thickness of the negative electrode became 150 μm, and the width of the negative electrode became 43.7 mm. The width of the diaphragm becomes 47 mm. The shape of the electrode assembly becomes an elliptical cylinder.

[0175] The resulting electrode assembly was inserted into an aluminum prismatic battery case of 49 mm high (bottom thickness: 0.5 mm), 34 mm wide, and 5.2 mm thick. After installing a 1.5 mm thick insulator on top of the electrode assembly, 2.5 g of the same electrolyte as in Example 1 was injected into the battery case. The distance A from the inner bottom surface of the battery case ...

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Abstract

A lithium secondary battery that is excellent in resistance to short-circuits and heat, is unlikely to suffer a capacity loss due to impact such as dropping, and has a high capacity. The lithium secondary battery includes: an electrode assembly including a strip-like positive electrode and a strip-like negative electrode that are wound together with a porous heat-resistant layer interposed therebetween; a non-aqueous electrolyte; and a battery can. The battery has a restricting part for restricting vertical movement of the electrode assembly. The distance A from the restricting part to the inner bottom face of the battery can and the width B of the negative electrode satisfy the relation: 0.965<=B / A<=0.995.

Description

technical field [0001] The present invention relates to a relatively safe lithium secondary battery having excellent short-circuit resistance and heat resistance. In particular, the present invention relates to a technique for preventing capacity loss of a battery due to impact such as dropping. Background technique [0002] Lithium secondary batteries have attracted attention as high-capacity power sources for portable devices and others. In addition, lithium secondary batteries have recently attracted increasing attention as high-output power sources for electric vehicles and the like. Chemical batteries such as lithium secondary batteries generally have a separator that electrically insulates the positive electrode from the negative electrode and holds the electrolyte. In lithium secondary batteries, microporous membranes made of polyolefins (such as polyethylene, polypropylene, etc.) are mainly used as separators. An electrode assembly ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/40H01M4/02H01M2/02H01M10/0525H01M10/0587H01M50/102H01M50/131H01M50/14H01M50/184H01M50/186
CPCY02T10/7011Y02E60/122Y02E60/10Y02P70/50
Inventor 藤川万乡铃木刚平井上薰岛田干也
Owner PANASONIC CORP
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