Composite separation membrane for secondary battery and preparation method thereof

A separation membrane, polymer technology, applied in the direction of secondary batteries, battery pack parts, circuits, etc., can solve the problems of reduced wettability, reduced discharge capacity, increased battery size, etc., to achieve the effect of excellent adhesion

Active Publication Date: 2022-04-05
SK INNOVATION CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

A separation membrane including an inorganic material layer has excellent thermal stability compared to a separation membrane prepared using only a porous polymer, but the inorganic material particles may detach due to shrinkage and deformation, and may not be able to maintain the same temperature continuously. Contact Force of Porous Polymer Substrates
Detachment of inorganic particles, etc., will increase the degree of shrinkage of the separation membrane due to heat, and the possibility of short-circuiting the battery due to rupture or melting of the separation membrane will increase.
In order to solve these problems, the thickness of the inorganic layer can be increased, but the increase in the thickness of the separation membrane will cause an increase in the size of the battery itself, a decrease in the transmittance, a decrease in wettability, and a difference in electrolyte concentration around the separation membrane. , resulting in poor main physical properties of the separation membrane and reduced discharge capacity

Method used

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  • Composite separation membrane for secondary battery and preparation method thereof
  • Composite separation membrane for secondary battery and preparation method thereof
  • Composite separation membrane for secondary battery and preparation method thereof

Examples

Experimental program
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preparation example Construction

[0071] The preparation method of the composite separation membrane of the present invention will be described in detail below.

[0072] The preparation method of the composite separation membrane of the present invention comprises the following steps: (a) coating a coating composition mixed with ceramic particles and a binder on one side or both sides of a porous polymer substrate and then drying, thereby forming a ceramic layer; (b) introducing and contacting a metal precursor on the surface of the porous polymer substrate and the surface of the ceramic layer; (c) purging with an inert gas; (d) introducing a gas containing an oxidizing agent A metal oxide layer is formed. The present invention may also include the step (e) of purging with an inert gas after the step (d).

[0073] The ceramic layer of the present invention can be formed in the following manner. Dissolve the adhesive in a solvent first, then add ceramic particles and stir to disperse, then coat on one or both...

Embodiment 1

[0111] In order to prepare polyolefin-based microporous membranes, a weight-average molecular weight of 3.8×10 5 High-density polyethylene, and dibutyl phthalate mixed in a ratio of 1:2 and paraffin wax with a kinematic viscosity of 160cSt at 40°C are used as a diluent, and the high-density polyethylene and the diluent are prepared with 30 wt. % and 70% by weight of the content of the mixed composition. Extrude the composition at a temperature of 240° C. using a twin-screw laminating machine equipped with a T-die, and induce phase separation by passing the extruded composition through a zone set at 180° C., and use casting rolls to produce Polyethylene porous substrate. Under the conditions of longitudinal (MD, Machine Direction) and transverse (TD, Transverse Direction) stretching ratios of 7.5 times and a stretching temperature of 131°C, it is obtained by successive biaxial stretching, and the heat setting temperature is 130 ℃, heat-fixed width of 1-1.3-1.1 to make. The f...

Embodiment 2

[0117] In the process of Example 1, in addition to introducing trimethylaluminum (Al(CH 3 ) 3 ) for 1 second and contact, after purging with argon (Ar) for 10 seconds, introduce water vapor (H 2 (0) for 1 second, and then again purged with argon (Ar) for 10 seconds, except that the number of repetitions was 60 times, and a composite separation membrane was prepared in the same way. At this time, the formed aluminum oxide (Al 2 o 3 ) layer is 10nm.

[0118] As a result of SEM-EDS measurement of the prepared composite separation membrane, the aluminum oxide layer was extended and formed on the surface of the polyethylene porous substrate and formed into the inside, and it was also confirmed in the ceramic layer by atomic layer deposition An aluminum oxide layer is formed.

[0119] The physical properties of the prepared composite separation membrane were measured, and the results are shown in Table 1.

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Abstract

The present invention relates to a composite separation membrane comprising: a porous polymer substrate; a ceramic layer formed on the porous polymer substrate; and a metal oxide layer formed by atomic layer deposition On ceramic layer and porous polymer substrate. The composite separation membrane has remarkable physical properties as a composite separation membrane for a secondary battery, and a secondary battery using the composite separation membrane is superior to conventional secondary batteries in terms of performance, life, and stability.

Description

technical field [0001] The invention relates to a composite separation membrane for a secondary battery and a preparation method thereof, and relates to a composite separation membrane suitable for a lithium secondary battery in the secondary battery and a preparation method thereof. Background technique [0002] In the structure constituting the secondary battery, the separation membrane plays an important role in improving the life and safety of the secondary battery. The separation membrane can prevent a short circuit caused by the contact of the cathode and anode of the secondary battery, and as a place where ions move in the secondary battery including the electrolyte, the separation membrane is required to have excellent physical properties in order to prepare an excellent secondary battery. [0003] Porous polymers are mainly used as materials for secondary battery separation membranes, and polyolefins with excellent mechanical strength and chemical stability are main...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M50/457H01M50/451H01M50/431H01M50/434H01M50/403H01M10/0525
CPCH01M10/0525H01M50/403H01M50/431H01M50/411H01M50/463Y02E60/10
Inventor 郭元燮刘鸿李济晏
Owner SK INNOVATION CO LTD
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