Separator for batteries and method for producing separator for batteries

A battery and separator technology, applied in the field of battery separators, can solve problems such as difficulty in ensuring safety, and achieve the effects of excellent shutdown performance, electrode adhesion, and excellent electrolyte permeability

Active Publication Date: 2015-10-14
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if thinning progresses, deformation tends to occur in the planar direction. Therefore, especially for battery separators laminated with a modified porous layer, it may be necessary to modify the porous layer during processing, in the slitting process, or in the battery assembly process. Layers are stripped, making security more difficult

Method used

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  • Separator for batteries and method for producing separator for batteries
  • Separator for batteries and method for producing separator for batteries
  • Separator for batteries and method for producing separator for batteries

Examples

Experimental program
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preparation example Construction

[0081] (1) Preparation process of polyolefin resin solution

[0082] The polyolefin resin solution is prepared by adding a suitable film-forming solvent to the above-mentioned 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.

[0083] 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 non-volatile li...

Embodiment 1

[0231] In 100 parts by mass, the mass average molecular weight (Mw) of 30 mass% is 2.5×10 6 The Mw of ultra-high molecular weight polyethylene (UHMWPE) and 70% by mass is 2.8×10 5 Dry mixing of 0.375 parts by mass of tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)- propionate] methane to give a mixture. ΔHm (≦125°C) measured for the PE composition composed of UHMWPE and HDPE was 11%, T (50%) was 134.7°C, and the crystal dispersion temperature was 100°C.

[0232] Mw of UHMWPE and HDPE was determined by gel permeation chromatography (GPC) under the following conditions (the same applies hereinafter).

[0233] ・Measuring device: GPC-150C manufactured by Waters Corporation

[0234] ・Column: Showa Denko Co., Ltd. "Shodex" (registered trademark) UT806M

[0235] ·Column temperature: 135℃

[0236] Solvent (mobile phase): o-dichlorobenzene

[0237] ·Solvent flow rate: 1.0mL / min

[0238] ・Sample concentration: 0.1% by mass (dissolution condition: 135°C / 1h)

[0239] ·Loa...

Embodiment 2

[0249] In 100 parts by mass, the mass average molecular weight (Mw) of 30 mass% is 2.5×10 6 The ultra-high molecular weight polyethylene (UHMWPE) and 70% by mass of Mw is 3.0×10 5 Dry mixing of 0.375 parts by mass of tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)- propionate] methane to give a mixture. ΔHm (≦125°C) measured for the PE composition composed of UHMWPE and HDPE was 14%, and T (50%) was 132.5°C.

[0250] 25 parts by mass of the obtained mixture was charged into a strong mixing type twin-screw extruder (amount of polyethylene composition input Q: 120 kg / h), and 75 parts by mass of liquid was supplied from the side feeder of the twin-screw extruder Paraffin wax was melt-kneaded at a temperature of 210° C. (Q / Ns: 0.3 kg / h / rpm) while maintaining the screw rotation speed Ns at 400 rpm to prepare a polyethylene solution.

[0251] The obtained polyethylene solution was supplied to a T-die from a twin-screw extruder, and extruded into a sheet-like molded body....

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Abstract

A separator for batteries, which is obtained by laminating a modified porous layer that contains a fluorine-based resin and inorganic particles or crosslinked polymer particles on one surface of a polyolefin microporous membrane having a thickness of 16 μm or less. This separator for batteries satisfies formula (1) and formula (2) described below, and the polyolefin microporous membrane is characterized in that (a) the shutdown temperature thereof is 135°C or less and (b) the air resistance change ratio thereof is 1 × 104 sec/100 cc/°C or more. A method for producing this separator for batteries. 0.01 ≤ absT(1200) ≤ 0.30 (1) absT(1200): the absorbance per a thickness of 10 μm of the polyolefin microporous membrane of the absorption having a peak at around 1,200 cm-1 as determined by infrared spectrometry (a transmission method) in cases where the modified porous layer is separated from the polyolefin microporous membrane 0.001 ≤ absR(1200) ≤ 0.030 (2) absR(1200): the absorbance at the maximum peak at around 1,200 cm-1 as determined by infrared spectrometry (a reflection method) of a surface of the polyolefin microporous membrane, said surface being on the reverse side of the modified porous layer. Consequently, the present invention provides: a separator for batteries, which has good adhesion to an electrode, excellent shutdown performance and excellent electrolyte solution permeability, and which is suitable for high-capacity batteries; and a method for producing this separator for batteries.

Description

technical field [0001] The present invention relates to a separator for a battery, which has adhesiveness to an electrode, has excellent shutdown performance, and is suitable for a high-capacity battery, and a method for producing the separator for a battery. Background technique [0002] Various characteristics are required for battery separators. In particular, separators for lithium-ion batteries require not only excellent mechanical properties and permeability, but also the properties (shutdown characteristics) that stop the battery reaction due to the closure of the pores due to heat generation in the battery. ) temperature to prevent film breakage properties (meltdown (meltdown) characteristics) and the like. Furthermore, in the above-mentioned separator, it is required to improve the adhesion to the electrode material in order to improve the cycle characteristics of the battery, and to improve the electrolyte solution permeability in order to improve the productivity...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16B32B5/32B32B27/30B32B27/32B29C48/92H01M50/403H01M50/406H01M50/417H01M50/426H01M50/449H01M50/489H01M50/491H01M50/494
CPCH01M2/1686B29C47/00B32B27/08B32B27/20B32B27/32B32B2264/0235B32B2264/025B32B2264/102B32B2307/306B32B2307/724B32B2307/726B32B2457/10H01M2/1653H01M2/166H01M10/0525B29C48/92Y02E60/10H01M50/403H01M50/446H01M50/449H01M50/417H01M50/491H01M50/406H01M50/494H01M50/489H01M50/426B29K2023/00B29L2007/00
Inventor 水野直树清水健
Owner TORAY IND INC
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