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Alumina slurry, method for producing same, and coating liquid

a technology of alumina slurry and alumina slurry, which is applied in the direction of cell components, sustainable manufacturing/processing, and final product manufacturing, etc., can solve the problems of short circuit, sometimes failed to suppress abnormal heat generation in separators composed of polyolefin porous films, etc., and achieve excellent shape stability and suppress powder falling

Inactive Publication Date: 2015-07-23
SUMITOMO CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patent introduces an alumina slurry that can be used to make a coating liquid for a separator in nonaqueous electrolyte secondary batteries. This slurry has excellent properties: it is heat-resistant and has high shape stability. The patent also includes a coating liquid made from this alumina slurry. This technology aims to improve the performance of these batteries.

Problems solved by technology

The nonaqueous electrolyte secondary battery typified by a lithium ion secondary battery has high energy density, and a large current flows to intensely generate heat when inner short circuit and outer short circuit occur due to breakage of the battery or accidents such as breakage of devices using the battery.
However, when heat is intensely generated, the separator composed of the polyolefin porous film may undergo shrinkage or film rupture, leading to direct contact between positive and negative electrodes, thus causing short circuit.
As mentioned above, the separator composed of the polyolefin porous film sometimes failed to suppress abnormal heat generation due to short circuit because of insufficient shape stability.
If powder falling occurs from the separator, expected physical properties of the separator do not appear, and also process defects such as contamination of devices with a powder fallen in the case of assembling into a battery.

Method used

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  • Alumina slurry, method for producing same, and coating liquid

Examples

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example 1

Production of Alumina Slurry 1

[0126]Alumina particles having a BET specific surface area of 4.1 m2 / g and an average particle diameter of 6.2 μm were added to water so that the concentration of alumina became 30% by weight while stirring the alumina particles to obtain an alumina-water suspension. Subsequently, using Dyno-Mill (KDL-PILOT A model) manufactured by AG MASCHINENFABRIK BASEL, dispersion was performed under wet grinding conditions (circumferential speed: 10 m / second, material of beads: ZrO2, diameter of beads; 1.0 mm, filling ratio of beads: 85% by volume, flow rate: 0.5 L / minute, and retention time: 4.4 minutes) in a path system to obtain an alumina slurry 1.

[0127]In the alumina slurry 1, a viscosity was 2.75 Pa·s, alumina particles included had an average particle diameter of 0.57 μm, and the amount of coarse particles of 10 μm or more was 3 ppm or less. The alumina slurry 1 was evaporated to dryness. As a result, the thus measured content of Zr in solid alumina was 1,01...

example 2

[0142]Using the same operation as in Example 1, except that wet grinding conditions were changed as follows: circumferential speed: 10 m / second, material of beads: ZrO2, diameter of beads: 1.0 mm, filling ratio of beads: 85% by volume, flow rate: 0.5 L / minute, and retention time: 5.8 minutes, an alumina slurry 2 of Example 2 was produced. In the thus obtained alumina slurry 2, a viscosity was 3.04 Pa·s, alumina particles included had an average particle diameter of 0.52 μm, and the amount of coarse particles of 10 μm or more was 3 ppm or less. The alumina slurry was evaporated to dryness. As a result, the thus measured content of Zr in solid alumina was 1,270 ppm calculated on a weight basis.

[0143]As is apparent from particle diameter distribution of alumina particles in the alumina slurry 2 shown in FIG. 1, alumina particles in the alumina slurry 2 were alumina particles, wherein

[0144]particles having a particle diameter of less than 0.2 μm accounts for 4.6% by weight,

[0145]particl...

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Abstract

Disclosed is an alumina slurry substantially including alpha-alumina particles and water, wherein the alpha-alumina particles satisfy all particle diameter distribution conditions (a) to (d) mentioned below, the alpha-alumina particles have an alumina purity of 90% by weight or more, the content of alumina in the slurry is 20% by weight or more and 50% by weight or less, and the slurry has a viscosity of 0.5 Pa·s or more and 15 Pa·s or less: condition (a): the average particle diameter is 1 μm or less, condition (b): particles having a particle diameter of less than 0.2 μm account for 7% by weight or less, condition (c): particles having a particle diameter of more than 1.5 μm account for 15% by weight or less, and condition (d): one or more frequency maximums exist in a particle diameter range of 0.1 μm or more and less than 0.5 μm.

Description

TECHNICAL FIELD[0001]The present invention relates to an alumina slurry and a method for producing the same, and a coating liquid. More particularly, the present invention relates to an alumina slurry as a raw material of a coating liquid which is suited for formation of a heat-resistant layer in a laminated porous film including the heat-resistant layer and a polyolefin porous film laminated to each other, and a method for producing the same.BACKGROUND ART[0002]A nonaqueous electrolyte secondary battery, especially a lithium ion secondary battery, has widely been used as a battery which is used in personal computers, mobile phones, mobile information terminals, and the like, because of its high energy density.[0003]The nonaqueous electrolyte secondary battery typified by a lithium ion secondary battery has high energy density, and a large current flows to intensely generate heat when inner short circuit and outer short circuit occur due to breakage of the battery or accidents such ...

Claims

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Application Information

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IPC IPC(8): C09D1/00C08K3/22C01F7/023C01F7/026H01M50/403H01M50/406H01M50/417H01M50/443H01M50/451H01M50/491
CPCC09D1/00C08K2003/2227C08K3/22H01M10/0525H01M10/058H01M50/403H01M50/451H01M50/443H01M50/491H01M50/417H01M50/406C01F7/026C01P2004/51C01P2004/53C01P2004/61C01P2004/62C01P2006/12C01P2006/22C01F7/023C01P2006/80Y02E60/10H01M50/446H01M50/431Y02P70/50
Inventor OZAKI, HIROTAKAFUJITA, NORIAKI
Owner SUMITOMO CHEM CO LTD
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