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Separator for nonaqueous electrolyte secondary cell, method for producing same, and nonaqueous electrolyte secondary cell

A non-aqueous electrolyte and secondary battery technology, applied in the direction of non-aqueous electrolyte batteries, lithium batteries, battery components, etc., can solve the problems of easy flow of polyethylene, temperature rise, fire, etc., and achieve excellent charge and discharge cycle characteristics, The effect of excellent load characteristics

Inactive Publication Date: 2013-11-06
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the temperature of the battery further rises after shutdown, the melted polyethylene tends to flow, and the so-called melting of the separator may occur.
In that case, the positive and negative electrodes are in direct contact, and the temperature rises further, and in the worst case, there is a risk of fire

Method used

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  • Separator for nonaqueous electrolyte secondary cell, method for producing same, and nonaqueous electrolyte secondary cell
  • Separator for nonaqueous electrolyte secondary cell, method for producing same, and nonaqueous electrolyte secondary cell
  • Separator for nonaqueous electrolyte secondary cell, method for producing same, and nonaqueous electrolyte secondary cell

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0126]

[0127] Urethane acrylate ("EBECRYL284" manufactured by Daicel-cytec Co., Ltd.) as an oligomer: 80 parts by mass, tripropylene glycol diacrylate as a monomer: 20 parts by mass, bis(2,4, 6-trimethylbenzoyl)-phenylphosphine oxide: 2 parts by mass, boehmite (average particle diameter: 1 μm) as inorganic particles (B): 300 parts by mass, and methyl ethyl ether as solvent (a) Base ketone and ethylene glycol as a solvent (c) in a volume ratio of 9:1 mixed solvent: 600 parts by mass, 5 times the amount (mass basis) of zirconia beads of φ1 mm are added to the boehmite, and the ball mill is used to uniformly After stirring continuously for 15 hours, filtration was performed to prepare a slurry for forming a separator.

[0128]

[0129] Graphite as a negative electrode active material: 95 parts by mass and PVDF: 5 parts by mass were mixed with N-methyl-2-pyrrolidone (NMP) as a solvent until uniform to prepare a paste containing a negative electrode mixture. The paste was ap...

Embodiment 2

[0143] The urethane acrylate as an oligomer was changed to "EBECRYL8402" manufactured by daicel-cytec Co., Ltd., the monomer was changed to 1,6-hexanediol diacrylate, and the boehmite was changed to Boehmite with an average particle size of 0.7 μm. Except that, the slurry for forming a separator was prepared in the same manner as in Example 1, and an integrated product of a separator and a negative electrode was produced in the same manner as in Example 1 except that the slurry for forming a separator was used. The volume V of the resin (A) in the diaphragm A and the volume V of the inorganic particle (B) B Ratio V A / V B is 0.8.

[0144] Furthermore, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the above-mentioned integrated product of the separator and the negative electrode was used.

Embodiment 3

[0146] Separator forming slurry was prepared in the same manner as in Example 1, except that the urethane acrylate as the oligomer was changed to "EBECRYL8402" manufactured by Daicel-Cytec Co., Ltd., and the monomer was changed to polyethylene glycol diacrylate. Except for using the slurry for forming a separator, an integrated product of a separator and a negative electrode was produced in the same manner as in Example 1. The volume V of the resin (A) in the diaphragm A and the volume V of the inorganic particle (B) B Ratio V A / V B is 0.8.

[0147] Furthermore, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the above-mentioned integrated product of the separator and the negative electrode was used.

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Abstract

A separator for a nonaqueous electrolyte secondary battery that at least includes a resin (A) having a crosslinked structure, which is obtained by irradiating with an energy ray an oligomer polymerizable by irradiation with an energy ray. The separator has an average pore size of 0.005 to 0.5 mum, an air permeability of 50 sec / 100 mL or more and less than 500 sec / 100 mL, where the air permeability is expressed as a Gurley value, and a thermal shrinkage of less than 2% at 175° C. The separator for a nonaqueous secondary battery can be produced by the production method of the present invention, which includes the steps of: applying to a substrate a separator forming composition containing the oligomer, two or more kinds of solvents having different polarity from each other, and the like; irradiating the applied composition with an energy ray; and drying the energy ray-irradiated composition.

Description

technical field [0001] The present invention relates to a nonaqueous electrolyte secondary battery excellent in load characteristics and charge-discharge cycle characteristics, a separator capable of constituting the nonaqueous electrolyte secondary battery, and a manufacturing method thereof. Background technique [0002] Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are widely used as power sources for portable devices such as mobile phones and notebook personal computers due to their high energy density. Improvement of characteristics and safety has become an important issue. [0003] In current lithium secondary batteries, a polyolefin-based porous film having a thickness of, for example, about 20 to 30 μm is used as a separator interposed between a positive electrode and a negative electrode. However, in the current situation, in order to open fine and uniform pores, complex steps such as biaxial stretching and extraction of a pore-ope...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M50/403H01M50/414H01M50/489
CPCY02E60/122H01M2/145H01M2/162H01M10/052H01M2/1653Y02E60/10H01M50/403Y02P70/50H01M50/414H01M50/489H01M50/446H01M50/491H01M50/46H01M2220/30H01M50/44
Inventor 古谷隆博儿岛映理渡边利幸小山邦彦
Owner HITACHI LTD