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EP-4742419-A1 - SEPARATOR FOR ELECTROCHEMICAL DEVICE, MANUFACTURING METHOD THEREFOR, AND ELECTROCHEMICAL DEVICE COMPRISING SEPARATOR

EP4742419A1EP 4742419 A1EP4742419 A1EP 4742419A1EP-4742419-A1

Abstract

The present disclosure relates to a separator for an electrochemical device, a method for manufacturing the same, and an electrochemical device including the separator, and more particularly, to a separator for an electrochemical device including an adhesive portion provided in a small amount on an outer portion of a coating layer, thereby improving dry adhesive strength and wet adhesive strength and preventing a phenomenon of separator folding during a lamination process, a method for manufacturing the same, and an electrochemical device including the separator.

Inventors

  • KIM, KYUNG TAE
  • KWON, Su Jee
  • JEONG, SO MI
  • BAE, WON SIK

Assignees

  • LG Energy Solution, Ltd.

Dates

Publication Date
20260513
Application Date
20240809

Claims (13)

  1. A separator for an electrochemical device, the separator comprising: a porous polymer substrate; a coating layer provided on at least one surface of the porous polymer substrate and including inorganic particles and a first polymer binder; and an adhesive portion provided on at least a portion of an outer portion of the coating layer and including second polymer binder particles and third polymer binder particles, wherein the adhesive portion includes a plurality of dots, and the plurality of dots are arranged in parallel in a supply direction (MD, machine direction) of the coating layer.
  2. The separator of claim 1, wherein the second polymer binder particle is an acryl-based polymer binder, and the third polymer binder particle is a polyvinyl acetate-based polymer binder.
  3. The separator of claim 1, wherein the second polymer binder particles and the third polymer binder particles have a weight ratio of 9:1 to 4:6.
  4. The separator of claim 1, wherein the adhesive portion has a predetermined pattern formed therein.
  5. The separator of claim 4, wherein the pattern includes a non-coating area in which the adhesive portion is not provided on at least a portion of an outer portion of the coating layer.
  6. The separator of claim 1, wherein the plurality of dots have a constant spacing.
  7. The separator of claim 6, wherein the plurality of dots have a spacing of 50 µm or greater and 500 µm or less.
  8. The separator of claim 1, wherein the adhesive portion has a thickness of 0.1 µm or greater and 1 µm or less.
  9. The separator of claim 2, wherein the acryl-based polymer binder has a degree of crosslinking of 70% or greater.
  10. A method for manufacturing a separator for an electrochemical device, the method comprising: providing a porous polymer substrate; providing a coating layer by coating a slurry for a coating layer including inorganic particles and a first polymer binder on at least one surface of the porous polymer substrate; and providing an adhesive portion by coating a slurry for an adhesive portion including an acryl-based polymer binder and a polyvinyl acetate-based polymer binder in a weight ratio of 9:1 to 4:6 on at least a portion of an outer portion of the coating layer in a supply direction (MD, machine direction) of the coating layer.
  11. The method of claim 10, wherein the providing of an adhesive portion by coating the slurry for an adhesive portion is performed using a spray, an inkjet, a dispenser or a nozzle.
  12. An electrochemical device comprising: a positive electrode; a negative electrode; and the separator of claim 1 interposed between the positive electrode and the negative electrode.
  13. The electrochemical device of claim 12, wherein the positive electrode includes a positive electrode tab portion formed to extend to one side, and the negative electrode includes a negative electrode tab portion formed to extend to the other side.

Description

Technical Field The present disclosure claims priority to and the benefits of Korean Patent Application Nos. 10-2023-0109314 and 10-2024-0106074 respectively filed with the Korean Intellectual Property Office on August 21, 2023 and August 8, 2024, the entire contents of which are incorporated herein by reference. The present disclosure relates to a separator for an electrochemical device, a method for manufacturing the same, and an electrochemical device including the separator. In particular, the present disclosure relates to a separator for an electrochemical device including an adhesive portion provided in a small amount on an outer portion of a coating layer, thereby capable of improving dry adhesive strength and wet adhesive strength and preventing a phenomenon of separator folding during a lamination process, a method for manufacturing the same, and an electrochemical device including the separator. Background Art In order to solve current problems in performance regarding separator folding of medium- to large-sized cells such as electric vehicles (EV) and energy storage systems (ESS), an ALS (advanced lamination & stacking (L&S)) method, which is an improved L&S (lamination & stacking) assembly process, may be applied. From the viewpoint of separator adhesive strength, an infrared heater (IR heater) may be used for uniform heat transfer during roll lamination and a short-side portion may be sealed to improve a phenomenon of folding of the short-side portion of a separator as a method of improving the ALS process. However, in the sealing of the short-side portion, a problem of damages to an electrode tab portion may occur, and it may be difficult to secure adhesive strength of the short-side portion of a separator since the sealing is conducted with weak pressure, resulting in a phenomenon of separator folding when injecting an electrolyte liquid. Accordingly, development of a separator for resolving the above-described problem and improving adhesive strength between an electrode and the separator has been required. DISCLOSURE Technical Problem The present disclosure is directed to providing a separator for an electrochemical device including an adhesive portion provided in a small amount on an outer portion of a coating layer to maintain adhesive strength during a process of manufacturing a secondary battery in which an electrode and a separator are laminated, a method for manufacturing the same, and an electrochemical device including the separator. However, problems to be solved by the present disclosure are not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. Technical Solution One embodiment of the present disclosure provides a separator for an electrochemical device, the separator including: a porous polymer substrate; a coating layer provided on at least one surface of the porous polymer substrate and including inorganic particles and a first polymer binder; and an adhesive portion provided on at least a portion of an outer portion of the coating layer and including second polymer binder particles and third polymer binder particles, wherein the adhesive portion includes a plurality of dots, and the plurality of dots are arranged in parallel in a supply direction (MD, machine direction) of the coating layer. According to one embodiment of the present disclosure, the second polymer binder particle may be an acryl-based polymer binder, and the third polymer binder particle may be a polyvinyl acetate-based polymer binder. According to one embodiment of the present disclosure, the second polymer binder particles and the third polymer binder particles may have a weight ratio of 9:1 to 4:6. According to one embodiment of the present disclosure, the adhesive portion may have a predetermined pattern formed therein. According to one embodiment of the present disclosure, the pattern may include a non-coating area in which the adhesive portion is not provided on at least a portion of an outer portion of the coating layer. According to one embodiment of the present disclosure, the plurality of dots may have a constant spacing. According to one embodiment of the present disclosure, the plurality of dots may have a spacing of 50 µm or greater and 500 µm or less. According to one embodiment of the present disclosure, the adhesive portion may have a thickness of 0.1 µm or greater and 1 µm or less. According to one embodiment of the present disclosure, the acryl-based polymer binder may have the degree of crosslinking of 70% or greater. One embodiment of the present disclosure provides a method for manufacturing a separator for an electrochemical device, the method including: providing a porous polymer substrate; providing a coating layer by coating a slurry for a coating layer including inorganic particles and a first polymer binder on at least one surface of the porous polymer substrate; and providing