Lithium secondary battery

A lithium secondary battery, potential technology, applied in the direction of secondary battery, lithium storage battery, secondary battery repair/maintenance, etc., can solve the problem of battery rupture, no overcharge safety, fire and other problems

Inactive Publication Date: 2004-03-31
SANYO ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the case of using γ-butyrolactone, compared with a battery using lithium manganate, sufficient safety against overcharge is not obtained.
[0006] In addition, such a technology has been used in the past to block the overcharge current, that is, using a microporous and porous separator made of polyolefin, when the heat generated by the progress of overcharge causes the battery temperature to rise to about At 120-130°C, the separator melts and blocks the holes on the separator, thereby cutting off the overcharge current. However, when the overcharge current is still supplied before reaching such a high temperature, due to the charging rate, the positive active material and the The electrolyte reacts thermally, sometimes causing the battery to rupture and catch fire

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The lithium secondary battery of Example 1 was fabricated as described below.

[0028] Make positive electrode

[0029] The positive electrode active material lithium cobaltate and the carbon conductive agent graphite were mixed at a mass ratio of 92:54 to make positive electrode mixture powder, which was filled into a mixing device (Mekanofujiyon device (AM-15F) manufactured by Hosokawa Micron Co., Ltd.). The mixing device was operated at a rotational speed of 1500 rpm (rev / min) for 10 minutes to apply compression, impact and shear force to the above powder to prepare a mixed positive electrode active material. This mixed positive electrode active material and fluorine-containing resin binder (polyvinylidene chloride: PVDF) are mixed in N-methylpyrrolidone (NMP) solvent by the mass ratio of 97:3, make positive electrode mixture slurry, this The slurry is coated on both sides of the aluminum foil, dried and then rolled to make a positive plate.

[0030] Make negat...

Embodiment 2

[0037]Except using tetrahydrofuran (THF) instead of 1,2-dimethoxyethane (DME) in the electrolytic solution, the same operation as in Example 1 was performed to manufacture a battery.

Embodiment 3

[0039] A battery was fabricated in the same manner as in Example 1 except that 2-methyltetrahydrofuran (2-MeTHF) was used instead of 1,2-dimethoxyethane (DME) in the electrolyte.

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PUM

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Abstract

A lithium secondary battery including a positive electrode which is capable of occluding and releasing lithium, a negative electrode which is capable of occluding and releasing lithium, a separator between the positive electrode and the negative electrode, and a nonaqueous electrolyte comprising a nonaqueous solvent and a wettability improving agent. The nonaqueous solvent does not substantially wet the separator, and the wettability improving agent is dissolved in the nonaqueous solvent, improves the wettability of the nonaqueous solvent to the separator, and has an oxidative decomposition potential in a range of 4.5 V to 6.2 V.

Description

technical field [0001] The present invention relates to lithium secondary batteries, and more particularly, the present invention relates to improvements in the safety of lithium secondary batteries. Background technique [0002] Lithium secondary batteries are used as power sources for electronic devices due to their small size, light weight, and high energy density. In particular, lithium secondary batteries using lithium cobalt oxide as the positive electrode active material are used as portable batteries due to their high energy density. Drive power for electronic devices. However, lithium cobalt oxide is easy to decompose due to overcharging. Therefore, in the past, when assembling lithium secondary batteries using lithium cobalt oxide, in order to prevent accidents such as battery rupture and fire caused by lithium cobalt oxide decomposition, it is often necessary to install battery protection. Circuits and other external safety mechanisms, but the cost of these circu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/05H01M6/16H01M10/052H01M10/0567H01M10/0569H01M10/42H01M50/417
CPCH01M2/1653H01M4/133H01M2300/0037H01M10/0567Y02E60/122H01M2300/0025H01M10/0525H01M4/131H01M10/4235H01M10/0569H01M10/0587Y02E60/10H01M50/417
Inventor 井町直希吉村精司
Owner SANYO ELECTRIC CO LTD
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