Separator for secondary battery having excellent electrolyte wettability and method for manufacturing same

A kind of secondary battery, electrolyte technology

Inactive Publication Date: 2014-10-01
TOPTEC HNS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, impregnating or coating with the heat-resistant resin blocks the pores of the polyolefin separator and restricts the movement of lithium ions, resulting in a decrease in charge-discharge characteristics.
Therefore, the separators and electrolyte membranes disclosed in the past still cannot satisfy heat resistance and ionic conductivity at the same time, and the heat-resistant coating also leads to a decrease in output characteristics.
Therefore, in reality, it is difficult to use it in high-energy-density and large-capacity batteries such as batteries for automotive power supplies that require not only heat resistance but also excellent performance under severe conditions such as rapid charge and discharge.

Method used

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  • Separator for secondary battery having excellent electrolyte wettability and method for manufacturing same

Examples

Experimental program
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Effect test

preparation example Construction

[0030] The preparation method of the polyolefin-based substrate is not limited, and is classified into a dry method and a wet method according to whether a solvent is used. The dry method is a method in which a crystalline polyolefin-based polymer is melt-extruded, molded, and a sheet is produced and heat-treated, and then stretched at a low or high temperature to form pores to prepare a separator. Since the dry method does not use a solvent, the process is simple and the productivity is excellent, but there are the following disadvantages: it is not conducive to the production of products with a wide width, the thickness of the separator is likely to be uneven, and mechanical strength is caused by uniaxial stretching. direction dependence etc. As for commercial polyolefin-based substrates prepared by the dry method, for example, Celgard series products of Celgard Company, U-Pore series products of Ube Company, and products of CS TECH Company can be cited.

[0031] The so-cal...

Embodiment

[0058] Hereinafter, the present invention will be described in more detail based on examples. These examples are only used to illustrate the present invention more specifically, and it will be obvious to those skilled in the art that the scope of the present invention is not limited to these examples

[0059]

[0060] 1. Puncture Strength

[0061] For puncture strength measurements, the samples were fixed in the test frame after being laid flat without creases. Apply a force of 1kgf to a needle with a diameter of 1mm until the fixed sample is pierced. The value at the time of poking is recorded in gf units. Samples were measured 10 times and the average value was taken.

[0062] 2. Air permeability

[0063] As far as air permeability measurement is concerned, it is set to a pressure of 600Pa and the measurement unit is cm 3 / cm 2 / s after the measurement. The samples were cut without wrinkling to 100mm in length and 100mm in width. Using air permeability measurin...

preparation example 1

[0072] [Preparation Example 1] Hot-melt first electrospinning composition

[0073] The hot-melt resin uses the EVA product HM7150PS of Okong bond Co., Ltd., which is added to the xylene (Xylene) solvent at a weight ratio of 20%, and the temperature is raised to 2-3 ° C per minute while stirring at a mixer speed of 1000 RPM. 40°C. After the temperature was raised to 40° C., stirring was carried out for 6 hours to completely dissolve the EVA resin in the xylene solution. After the temperature of the dissolved solution was lowered to 25°C, 0.3% of a conductivity modifier and 3% of a viscosity modifier (BYK company, VISCOBYK-15130) were added as additives, and stirred for 1 hour to prepare the first electrospinning combination. The prepared composition had a viscosity of 600 cPs and an electrical conductivity of 9 ms / cm.

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Abstract

The present invention relates to a highly wettable separator for a secondary battery, and provides a highly wettable separator for a secondary battery, the separator comprising: a polyolefin-based substrate; a hot melt nanofiber layer formed on one surface or both surfaces of the substrate; and a nanofiber layer with high electrolyte wettability, the nanofiber layer being formed on the hot melt nanofiber layer, wherein the coating amount of the hot melt nanofiber layer is 0.05-2.5 g / m2 and the layer with high electrolyte wettability has a porosity of 55-89%. The separator according to the present invention can exhibit a shutdown function while having excellent heat resistance and high mechanical strength, and can exhibit excellent ion conductivity and prevent deterioration in battery performance by having excellent pore size and porosity.

Description

technical field [0001] The invention relates to a separator for a secondary battery with excellent electrolyte wettability and a preparation method thereof. Background technique [0002] With the increasing trend such as higher performance, lighter weight, and automotive power supplies, secondary batteries such as lithium-ion secondary batteries, lithium polymer secondary batteries, and supercapacitors (electric double-layer capacitors and the like) are required to have High energy density, large capacity and thermal stability. [0003] However, the actual situation is that existing lithium-ion secondary batteries using polyolefin separators and liquid electrolytes, and existing lithium-ion secondary batteries using gel-coated polymer electrolyte membranes or polyolefin separators When polymer batteries are used as high-energy-density and high-capacity batteries, there is a big deficiency in heat resistance. [0004] The separator is located between the anode and cathode o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16B32B27/32D04H1/728H01M50/403H01M50/414H01M50/451H01M50/457H01M50/489H01M50/491
CPCH01M2/1686D04H1/728B32B27/32H01M2/145H01M2/1653H01M2/162H01M50/44H01M50/403H01M50/451H01M50/491H01M50/489H01M50/414H01M50/457B32B7/12B32B27/12B32B2307/54B32B2457/10Y02E60/10
Inventor 李乡斗
Owner TOPTEC HNS
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