KR-102961091-B1 - SEALANT FILM, POUCH FILM LAMINATE COMPRISING THE SAME, POUCH-TYPE BATTERY CASE AND METHOD FOR MANUFACTURING THE SAME

Abstract

The present invention relates to a sealant film comprising a matrix resin and a domain resin included within the matrix resin, a multilayer structure comprising a metal adhesive layer, a core layer, and a heat sealing layer, wherein the surface of the heat sealing layer has a surface roughness Ra of 0.03 or more and 0.1 or less, Rz of 0.2 or more and 0.5 or less, Rt of 0.2 or more and 0.5 or less, and Rsm of 5.8 or more and 75 or less.

Inventors

• 장지은
• 송녹정
• 한희식
• 김유한
• 황선수

Assignees

• 율촌화학 주식회사

Dates

Publication Date

20260507

Application Date

20231228

Priority Date

20231025

Claims (13)

1. A matrix resin; and a domain resin included within the matrix resin, comprising: It is a multilayer structure comprising a metal adhesive layer; a core layer; and a heat-bonding layer, and The surface of the heat-sealed layer has a surface roughness Ra of 0.03 or higher and 0.1 or lower, Rz of 0.2 or higher and 0.5 or lower, Rt of 0.2 or higher and 0.45 or lower, and Rsm of 5.8 or higher and 75 or lower, and The above domain resin is included in an amount of 1% or more and 15% or less by weight relative to the total resin, and A sealant film having an average particle size of the domain resin of 50 nm or more and 140 nm or less.
2. delete
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4. In claim 1, A sealant film in which the surface of the heat-sealable layer is surface-modified by the domain resin.
5. In claim 1, The above-mentioned matrix resin is a sealant film comprising a polyolefin-based resin.
6. In claim 1, A sealant film comprising one or more materials selected from the group consisting of polyolefin elastomers, polymethyl methacrylate, EPDM, silica, CaCO₃ , BaSO₄ , zeolite, and Talc.
7. In claim 1, A sealant film having a static friction coefficient of 0.2 or more and 0.23 or less on the surface of the heat-bonded layer.
8. Sealant film according to claim 1; outer layer film; and A pouch film laminate comprising a barrier layer film containing aluminum, disposed between the sealant film and the outer layer film.
9. In claim 8, The above outer layer film is a pouch film laminate comprising polyethylene terephthalate.
10. A pouch-type secondary battery case comprising a pouch film laminate according to claim 8.
11. A step of matting the surface of the heat-sealable layer by adding a surface modifier in an amount of 1% or more and 15% or less by weight relative to the total resin; A step of further adding a slip agent to the heat-sealed layer; and A method for manufacturing a sealant film comprising the step of laminating a metal adhesive layer, a core layer, and the heat-sealing layer.
12. In claim 11, A method for manufacturing a sealant film, wherein the surface modifier comprises one or more materials selected from the group consisting of polyolefin elastomer, polymethyl methacrylate, EPDM, silica, CaCO₃ , BaSO₄ , zeolite, and Talc.
13. In claim 11, A method for manufacturing a sealant film in which the slip agent is added in an amount of 0.01 weight% or more and 0.5 weight% or less.

Description

Sealant film, pouch film laminate comprising the same, pouch-type battery case and method for manufacturing the same The present invention relates to a sealant film, a pouch film laminate including the same, a pouch-type battery case, and a method for manufacturing the same. Types of secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and lithium-ion polymer batteries. These secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and E-bikes, but also in large products requiring high output such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated power or renewable energy. To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to produce a positive electrode and a negative electrode, and these are stacked on both sides of a separator to form an electrode assembly of a predetermined shape. Then, the electrode assembly is housed in a battery case, and after injecting an electrolyte, it is sealed. Secondary batteries can be classified into pouch type, cylindrical type, prismatic type, etc., depending on the type of outer material of the case that accommodates the electrode assembly. Among these secondary batteries, pouch-type batteries are a form in which an electrode assembly (cell) is embedded in a pouch made of a metal laminate sheet. They are primarily utilized in fields requiring high-capacity secondary batteries, such as electric vehicles, because they offer the advantages of easy manufacturing, low production costs, and the ease of manufacturing large-capacity battery packs by connecting multiple unit cells in series or parallel. The pouch, which serves as the case for the pouch-type secondary battery, is manufactured by performing press processing on a flexible pouch film laminate to form a cup portion. Once the cup portion is formed, the electrode assembly is housed in the receiving space of the cup portion, and the sealing portion is sealed to manufacture the secondary battery. Meanwhile, conventional pouch film products are manufactured using a slip agent. Using the slip agent allows for slipperiness to be imparted to the PP surface of the sealant layer and the PET surface of the outer protective layer during film extrusion and winding operations, thereby facilitating film forming. However, using an excessive amount of the slip agent presents a problem in that it can contaminate the molding die of the film forming machine. Furthermore, since such contamination can cause cracks or fissures as foreign substances during film product forming and damage may occur due to the contamination of the film forming machine, conventional pouch film products minimize this contamination of the film forming machine by using a minimum amount of the slip agent. However, when the above slip agent is used in a minimum amount, the slip agent does not migrate initially, causing the friction coefficient of the product to increase, resulting in problems with molding, and additional problems arise such as equipment contamination caused by an excessive amount of slip agent as the working time progresses. Figure 1 shows the surface of the heat-sealed layer of the surface-modified sealant film of Comparative Example 1, captured with a laser surface roughness measuring instrument. Figure 2 shows the surface of the heat-sealed layer of the surface-modified sealant film of Example 1, captured with a laser surface roughness measuring instrument. Figure 3 shows the surface of the heat-sealed layer of the surface-modified sealant film of Example 2, captured with a laser surface roughness measuring instrument. Figure 4 shows the surface of the heat-sealed layer of the surface-modified sealant film of Comparative Example 2, captured with a laser surface roughness measuring instrument. Figure 5 shows the degree of transfer of the slip agent included between the outer layer (PET layer) film and the sealant (PP) film of the example and comparative example during the winding process. Hereinafter, the present invention will be described in more detail to aid in understanding the invention. In this case, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. The terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indic