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Laminated porous film and separator for electrical storage devices

A technology of porous film and porous layer, applied in circuits, electrical components, layered products, etc., can solve the problems of battery performance deterioration, high water content, heat resistance, insufficient dimensional stability, etc., and achieve excellent coating properties, The effect of low water content and excellent battery performance

Active Publication Date: 2016-08-31
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, when the porous membrane produced by the above method is used alone, there are problems in that the heat resistance and dimensional stability are insufficient, and the penetration of impurities mixed into the battery cannot be prevented.
[0003] In addition, a method of improving heat resistance by laminating a layer of inorganic particles on a porous film made of an olefinic resin has been proposed (see, for example, Patent Documents 3 to 5). However, due to the high water content contained in the porous film , so when used as a separator for a lithium-ion secondary battery, the contained moisture reacts with lithium, deteriorating the material used, and causing deterioration in battery performance.
Therefore, as a method of reducing the water content of the porous membrane, a method of hydrophobizing the inorganic particles has been proposed (for example, see Patent Document 6), but the hydrophobizing agent may reduce the performance of the battery.
In addition, a method of using a heat-resistant resin as a base material of the separator and dehydrating at a high temperature has been proposed (for example, see Patent Document 7). The problem of high cost

Method used

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  • Laminated porous film and separator for electrical storage devices
  • Laminated porous film and separator for electrical storage devices
  • Laminated porous film and separator for electrical storage devices

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0172] Mix 99.4% by mass of high-density polyethylene (density 0.95, viscosity average molecular weight: 250,000) as resin (D), and tetrakis-[methylene-(3', 5'-di-tert-butyl 4' as antioxidant) -Hydroxyphenyl) propionate] methane 0.6% by mass was supplied to the extruder using a feeder. In addition, liquid paraffin was injected into the extruder using a side feeder so that it became 100 parts by mass with respect to 100 parts by mass of resin (D), and a twin-screw extruder with a diameter of 25 mm and L / D=48 was used. After melting and kneading under the conditions of ℃ and 200 rpm, it was extruded from a T-die installed at the front end of the extruder.

[0173] Immediately, it was cooled and solidified with a casting roll cooled to 25° C., and molded into an unstretched sheet with a thickness of 1.2 mm. The unstretched sheet was stretched to 7×7 times under the condition of 120° C. by a simultaneous biaxial stretching machine, immersed in dichloromethane, extracted to remove...

Embodiment 2～12

[0176]94.45% by mass of polypropylene (Sumitomo Chemical Co., Ltd., FLX80E4) as the raw material of the porous membrane, resin (D), and "Engage (registered trademark)" manufactured by Dow Chemical Co. as an ethylene-1-octene copolymer 8411 (melt index: 18g / 10 minutes, hereinafter abbreviated as PE-1) 5% by mass, and N,N'-dicyclohexyl-2,6-naphthalene dicarboxamide (new Nihon Rika Co., Ltd., Nu-100, hereinafter abbreviated as β crystal nucleating agent) 0.3% by mass, "IRGANOX (registered trademark)" 1010, "IRGAFOS (registered trademark)" 168 manufactured by Ciba Specialty Chemicals as antioxidants 0.15% by mass and 0.1% by mass respectively, mixed according to the above-mentioned ratio, and the above-mentioned raw materials were supplied from the weighing hopper to the twin-screw extruder, melted and kneaded at 300°C, and discharged from the mold in the form of strips. Cool and solidify in a water tank at 25°C, and cut into chips as chip raw materials.

[0177] The chips were s...

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Abstract

The present invention provides a laminated porous film suitable for use as a separator for an electrical storage device, which can achieve excellent battery performance, heat resistance, and cost reduction, and is also of high quality. The laminated porous film of the present invention is characterized in that a porous layer containing inorganic particles (A), at least two types of water-soluble polymers (B) and a resin (C) is provided on at least one side of a substrate.

Description

technical field [0001] The present invention relates to a laminated porous film that is excellent in electrical properties and safety and can be used as a separator for an electrical storage device. Specifically, it relates to a laminated porous film having excellent safety, excellent film physical properties, high battery performance, and high quality by providing a porous layer on the porous film, Therefore, it is suitable as a separator for an electrical storage device. Background technique [0002] Porous membranes made of polyolefins not only have excellent electrical insulation and ion permeability, but also have excellent mechanical properties, so they are widely used in separators for lithium-ion secondary batteries. In order to increase the energy density, studies on increasing the pore size, thinning the membrane, increasing the porosity, etc. of the membrane are being conducted (for example, refer to Patent Documents 1 and 2). However, when the porous membrane p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16B32B5/18C08J9/00H01M50/417H01M50/429H01M50/491
CPCB32B5/18C08J9/00H01M50/446H01M50/491H01M50/429H01M50/417Y02E60/10H01M50/4295H01M50/44H01M50/449H01M50/403C08J5/22Y02P70/50
Inventor 横山希若原叶子东大路卓司
Owner TORAY IND INC