Battery separator

A separator and battery technology, applied in the field of battery separators, can solve problems such as insufficient shutdown characteristics, and achieve the effects of excellent electrode adhesion, excellent heat shrinkage resistance, and high rate of change in air permeability

Active Publication Date: 2015-08-05
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, although they have adhesion to electrodes, their shutdown characteristics are not sufficient
[0013] That is, the current situation is that a laminated polyolefin microporous membrane that fully exhibits the shutdown characteristics of polyolefin microporous membranes and has both shutdown characteristics and electrode adhesion has not been obtained so far.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0064] (1) Preparation process of polyolefin resin solution

[0065] The polyolefin resin solution is prepared by adding a suitable film-forming solvent to a polyolefin resin, followed by melt-kneading. Various additives such as the above-mentioned inorganic fillers, antioxidants, ultraviolet absorbers, antiblocking agents, pigments, and dyes can be added to the polyolefin resin solution as needed within a range that does not impair the effects of the present invention. For example, micronized silicic acid can be added as a pore former.

[0066] As the film-forming solvent, any of liquid solvents and solid solvents can be used. Examples of the liquid solvent include aliphatic or cyclic hydrocarbons such as nonane, decane, decalin, p-xylene, undecane, dodecane, and liquid paraffin, and mineral oil fractions having boiling points corresponding to them. In order to obtain a gel-like sheet with a stable solvent content, it is preferable to use a nonvolatile liquid solvent such a...

Embodiment 1

[0193] In the mass average molecular weight (Mw) of 2.5 × 10 6 Ultra-high molecular weight polyethylene (UHMwPE) 30% by mass and Mw is 3.0×10 5 Dry-mixing tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl )-propionate] methane 0.375 parts by mass. For the PE composition composed of UHMWPE and HDPE, the measured ΔHm (≤125°C) is 14%, T (50%) is 132.5°C, melting point is 135°C, and crystal dispersion temperature is 100°C.

[0194] Mw of UHMwPE and HDPE was obtained by gel permeation chromatography (GPC) under the following conditions (the same applies hereinafter).

[0195] ・Measuring device: GPC-150C manufactured by Waters Corporation

[0196] ・Column: Shodex UT806M manufactured by Showa Denko Co., Ltd.

[0197] ·Column temperature: 135℃

[0198] Solvent (mobile phase): o-dichlorobenzene

[0199] ·Solvent flow rate: 1.0mL / min

[0200] ・Sample concentration: 0.1% by mass (dissolution condition: 135°C / 1h)

[0201] ·Loading volume: 500μL

[0202] Detector: Differenti...

Embodiment 2

[0211] In the production of the polyethylene microporous membrane of Example 1, the polyethylene composition was adjusted while maintaining the ratio of the input amount of the polyethylene composition to the screw speed Ns at Q / Ns=0.3kg / h / rpm. The amount of input material and the rotational speed of the screw were used to prepare a polyethylene microporous membrane (b) with a thickness of 9 μm and an air impermeability of 70 sec / 100 ccAir. Next, a modified porous layer was laminated on one side of the polyethylene microporous membrane (b) by the same method as in Example 1 to obtain a battery separator having a final thickness of 11 μm.

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Abstract

Provided is a battery separator comprising a microporous polyolefin membrane and a modifying porous layer laminated on at least one surface of the microporous polyolefin membrane, wherein the microporous polyolefin membrane comprises a polyethylene resin, and the modifying porous layer is laminated on at least one surface of the microporous polyolefin membrane having (a) a shutdown temperature of 135°C or lower, (b) a rate of air resistance change of 1 × 10 4 sec / 100 cc / °C or more, and (c) a transverse shrinkage rate at 130°C of 20% or less. Provided is a battery separator having high physical stability before the start of shutdown, a high rate of air resistance change after the start of shutdown, excellent heat shrinkage resistance in a temperature range from a shutdown start temperature to a shutdown temperature, a low shutdown temperature, and excellent adhesion to electrode.

Description

technical field [0001] The present invention relates to a separator for a battery, and in particular to a temperature from a shutdown start temperature to a shutdown temperature with a high stability of physical properties until the start of shutdown and a high rate of change in air resistance after the start of shutdown. A separator for batteries with excellent heat shrinkage resistance within the range and low shutdown temperature. Background technique [0002] One of the main applications of polyethylene microporous membranes is battery separators, and there are various required characteristics for battery separators. In particular, separators for lithium-ion batteries require not only excellent mechanical properties and permeability, but also properties (shutdown characteristics) that stop the battery reaction by closing the pores due to heat generation in the battery. Properties (meltdown characteristics) to prevent film breakage at temperature, and the like. [0003]...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M50/417H01M50/426H01M50/449H01M50/489
CPCH01M2/166H01M2/1686H01M2/1653B01D71/26H01M50/446H01M50/449H01M50/426H01M50/489H01M50/417Y02E60/10
Inventor 水野直树君岛康太郎清水健
Owner TORAY IND INC
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