EP-4741066-A1 - NOVEL COATING DEVICE AND METHOD FOR COATING SEPARATOR FOR ELECTROCHEMICAL DEVICE USING SAME

EP4741066A1EP 4741066 A1EP4741066 A1EP 4741066A1EP-4741066-A1

Abstract

The present disclosure relates to a novel device for coating of a separator for an electrochemical device and a coating method using the same. Specifically, according to an aspect of the present disclosure, there is an advantage of efficiently pattern-coating a binder on the surface of a separator. In addition, the present disclosure has an advantage of providing a coating method that is easy to change a pattern by reversibly modifying the surface of a coating bar for pattern coating.

Inventors

LEE, SEUNG-HYUN
KIM, Yu-Bae
LEE, Byeong-Kyu
KA, Kyung-Ryun

Assignees

LG Energy Solution, Ltd.

Dates

Publication Date: 20260513
Application Date: 20250425

Claims (14)

A coating device comprising: a coating bar of a cylindrical shape, a surface treatment unit spaced apart from the coating bar, and a pattern masking unit positioned between the coating bar and the surface treatment unit, wherein the surface treatment unit includes at least one of a plasma irradiator or a corona irradiator, and wherein the pattern masking unit has a penetrable area and an impenetrable area of plasma or corona.
The coating device according to claim 1, wherein the pattern masking unit is made of a metal plate or a polymer film.
The coating device according to claim 1, wherein the pattern masking unit has a pattern where the penetrable area and the impenetrable area are repeatedly arranged in an alternating manner.
The coating device according to claim 1, further comprising: a coating solution tank to provide a coating solution to at least a part of the surface of the surface-treated coating bar, wherein the coating solution includes a binder.
The coating device according to claim 4, wherein the coating solution further includes inorganic particles.
The coating device according to claim 1, further comprising: a transport unit to provide a coating substrate to the coating bar, at least a part of the surface of which is coated with the coating solution.
The coating device according to claim 6, wherein the coating substrate is a separator for an electrochemical device.
A method for coating a separator for an electrochemical device, comprising: (S1) treating at least a part of a surface of a coating bar of a cylindrical shape, and (S2) coating a coating solution containing a binder on at least one surface of a coating substrate using the surface-treated coating bar, wherein the step (S1) includes irradiating plasma or corona onto the surface of the coating bar, at least a part of which has been pattern-masked.
The method for coating the separator for the electrochemical device according to claim 8, wherein the surface of the coating bar before the surface treatment in the step (S1) is hydrophobic, and the surface of the coating bar with the surface treatment is modified to make it hydrophilic.
The method for coating the separator for the electrochemical device according to claim 8, wherein the coating solution is a dispersion in which the binder is dispersed in an aqueous solvent.
The method for coating the separator for the electrochemical device according to claim 8, wherein the coating solution further includes inorganic particles.
The method for coating the separator for the electrochemical device according to claim 8, wherein the coating substrate includes a porous polymer substrate.
The method for coating the separator for the electrochemical device according to claim 8, wherein the coating substrate includes a porous polymer substrate and a porous coating layer on at least one surface of the porous polymer substrate, the porous coating layer including inorganic particles.
A separator for an electrochemical device having at least one surface coated by the method according to any one of claims 8 to 13, wherein the coated surface of the separator has pattern coating with the binder.

Description

TECHNICAL FIELD The present disclosure relates to a novel device for coating a separator for an electrochemical device, a coating method of a separator using the same and a coated separator using the same. BACKGROUND A lithium secondary battery is manufactured through processes of inserting an electrode assembly including positive electrode/separator/negative electrode as a unit into a battery case, injecting an electrolyte solution and sealing the battery case. In this instance, recently, many studies are being conducted to modify the separator to help the separator to perform a function of blocking physical contact between the positive electrode and the negative electrode, and ensure stability of lithium secondary batteries such as flame retardancy and flame resistance. Firstly, to solve a short circuit between the positive electrode and the negative electrode that occurs when the separator is separated from the positive electrode and the negative electrode adjacent to the separator during operation of the battery, there is a challenge to improve the adhesion strength of the separator with respect to the positive electrode and the negative electrode. To this end, technology has been developed to form an adhesive layer on the surface of the separator by using an adhesive binder. However, when the binder is applied to the entire surface of the separator, interfacial resistance between the separator and the electrode increases. In addition, when the adhesive layer is formed over the entire surface of the separator, a slitting portion may contact the adhesive layer when tailoring the separator into a desired shape at the later stage of the separator manufacturing process, causing device contamination and quality degradation of the separator. In addition to the technology that forms the adhesive layer on the surface of the separator, technology that coats the surface of the separator with inorganic particles to provide flame retardancy to the surface of the separator is being developed. In this instance, because the surface of the separator coated with the inorganic particles has little or no adhesion strength, technology that forms an adhesive layer on the inorganic particle coating layer to provide additional adhesion strength is being developed. Likewise, when the adhesive layer is formed over the entire surface of the inorganic particle coating layer, the resistance of the separator increases, and the adhesive layer may not be evenly formed on the porous coating layer. To solve these problems, technology has been devised to form the adhesive layer on the surface of the separator into a pattern shape. Despite many studies with varying composition of the coating layer, ideal pattern coating has not yet been achieved due to a lack of technology for pattern coating on the surface of the separator. Accordingly, the present disclosure aims to provide a novel coating device and method that may be used for coating of the separator. DISCLOSURE Technical Problem The present disclosure is directed to providing a coating device designed to solve the above-described problems, a coating method and a coated separator for an electrochemical device using the same. Specifically, according to an aspect of the present disclosure, the present disclosure is directed to providing a novel device for coating an adhesive layer on the surface of a separator into a pattern shape. In particular, according to an aspect of the present disclosure, the present disclosure is directed to providing a pattern varying coating device for forming various patterns on the surface of the separator and a coating method using the same. Further, according to an aspect of the present disclosure, the present disclosure is directed to providing a method for manufacturing a separator having an adhesive layer on the surface in a pattern shape, thereby enhancing the ease of a slitting process of the separator. In addition, the present disclosure is directed to providing a separator for an electrochemical device with improved resistance characteristics and adhesive characteristics, manufactured by using the novel device. Technical Solution To achieve the above-described objectives, according to an aspect of the present disclosure, provided is a coating device of the following embodiments. The coating device according to a first embodiment includes: a coating bar of a cylindrical shape,a surface treatment unit spaced apart from the coating bar, anda pattern masking unit positioned between the coating bar and the surface treatment unit,wherein the surface treatment unit includes at least one of a plasma irradiator or a corona irradiator, andwherein the pattern masking unit has a penetrable area and an impenetrable area of plasma or corona. According to a second embodiment, in the first embodiment, the pattern masking unit may be made of a metal plate or a polymer film. According to a third embodiment, in the first or second embodiment, the pattern masking unit