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KR-102763173-B9 - FILM FOR CELL POUCH WITH MINIMAL DEFORMATION OF LAMINATE AND MANUFACTURING METHOD THEREOF

KR102763173B9KR 102763173 B9KR102763173 B9KR 102763173B9KR-102763173-B9

Abstract

The present specification discloses a film for a cell pouch that can minimize the winding tension applied to a metal layer and a cell pouch film through improvements in the manufacturing process, thereby minimizing mechanical deformation of the metal layer and minimizing deformation of the cell pouch film laminate, improving tensile strength and formability, and improving curl characteristics before and after molding, a cell pouch including the same, and a method for manufacturing said film.

Inventors

  • 송녹정
  • 한희식
  • 이지민
  • 박한철
  • 김희훈
  • 이두희
  • 김건룡

Assignees

  • 율촌화학 주식회사

Dates

Publication Date
20260513
Application Date
20230406

Claims (17)

  1. Sealant layer; An inner adhesive layer laminated on the above sealant layer; A barrier layer laminated on the inner adhesive layer above; An outer surface adhesive layer laminated on the above barrier layer; and A cell pouch film comprising an outer layer formed on the outer adhesive layer above, The curl deviation of the cell pouch film before molding, measured by the following method, is 3mm or less, and The above barrier layer is an aluminum layer, and The above outer layer and sealant layer are each characterized by containing a resin, The above aluminum layer has surface-treated surfaces on both sides, and A cell pouch film having a thickness of 40 to 80 μm for the aluminum layer and a thickness of 80 to 100 μm for the sealant layer. [Curl Evaluation Before Cell Pouch Film Molding] A cell pouch film specimen was prepared in a rectangular shape measuring 15cm x 15cm, and the specimen was placed on a flat stand and secured flat with tape. An X-shaped cut of 15 cm length was made passing through the center point of the fixed specimen, and the height raised (curled) was measured at two points on the MD (longitudinal) side and two points on the TD (transverse) side with the center point in between. The deviation was calculated as the difference between each MD measurement and TD measurement.
  2. In Article 1, The cell pouch film above is characterized by having a curl deviation of 5mm or less after molding, measured by the following method. [Curl Evaluation After Surgery] ① MD Directional Forming (MD Forming Curl Evaluation) A molded specimen was prepared with dimensions of 26.6 (MD) X 24.0 (TD) cm. The molding evaluation was performed on a chrome-coated 1-cup molding machine at 0.3 MPa. The R value (radius of curvature of the edge) of the molding machine was 4R (4 mm), the forming size during molding was 90 mm X 160 mm, and the process was performed as a single forming. ② TD Directional Forming (TD Forming Curl Evaluation) A molded specimen was prepared with dimensions of 26.6 (TD) X 24.0 (MD) cm. A molding evaluation was conducted on a chrome-coated 1-cup molding machine at 0.3 MPa. The R value (radius of curvature) of the molding machine was 4R (4 mm), the forming size was 90 mm X 160 mm, and the process was performed as a single forming. To evaluate the curl generated after molding, double-sided tape was installed on a flat surface, and the molded pouch was fixed thereon to measure the height of the resulting curl. Two measurement points were measured, and the higher value was recorded. After measuring each corner of the molded sample, the height of the corner where the curl was greater was taken as the curl value.
  3. In Article 2, A cell pouch film characterized in that, in the above cell pouch film, the barrier layer is not wound alone during the manufacturing process but is wound together with at least the outer layer.
  4. In Paragraph 3, The cell pouch film is characterized by being wound two or fewer times during the manufacturing process.
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  6. In Article 1, A film for a cell pouch characterized in that the outer layer comprises one or more resins selected from the group consisting of nylon resin, polyethylene terephthalate (PET), and polybutylene terephthalate (PBT) resin.
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  8. In Article 1, A film for a cell pouch characterized in that the inner adhesive layer and the outer adhesive layer comprise one or more of an epoxy-based adhesive, a polyurethane-based adhesive, a phenolic resin-based adhesive, a polyolefin-based adhesive, and a polyester-based adhesive.
  9. In Article 1, A film for a cell pouch characterized in that the inner adhesive layer is an adhesive coating layer; an extrusion coating layer; or an adhesive coating layer and an extrusion coating layer.
  10. In Article 1, A film for a cell pouch characterized in that the sealant layer is a sealant film or an extruded resin layer.
  11. A cell pouch characterized by being composed of a cell pouch film according to any one of claims 1 to 4, 6, and 8 to 10.
  12. A secondary battery characterized by being externally enclosed in a cell pouch of claim 11.
  13. A method for manufacturing a cell pouch film according to any one of claims 1 to 4, 6, and 8 to 10, A double-sided surface treatment step for surface treating both sides of the aluminum fabric included in the barrier layer; An outer surface adhesive layer coating step of forming an outer surface adhesive layer by applying an adhesive to one side of the surface-treated aluminum fabric; and It includes an outer layer lamination step of laminating an outer layer fabric onto the upper surface of the outer adhesive layer; The above cell pouch film is subjected to two-turn winding during the manufacturing process, and The barrier layer in the cell pouch film is characterized by not being wound alone during the manufacturing process, but being wound together with the outer layer, or being wound together with the outer layer and the sealant layer. The above double-sided surface treatment step is such that, immediately after surface treatment of one side of the aluminum fabric, surface treatment of the other side of the aluminum fabric is performed sequentially without a drying step. The above manufacturing method further includes a physical property stabilization drying step between the double-sided surface treatment step and the outer surface adhesive layer coating step, wherein the aluminum fabric with surface-treated sides is dried in a floating manner to stabilize physical properties. The above manufacturing method is, A step of performing a first winding after the above outer layer lamination step; An inner adhesive layer coating step of forming an inner adhesive layer by applying an adhesive to the other side of the surface-treated aluminum fabric after the above-mentioned single winding, where the outer layer is not laminated; A step of laminating a sealant layer fabric to the lower part of the inner adhesive layer; and A method for manufacturing a cell pouch film, comprising the step of performing a second winding after laminating the sealant layer fabric.
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  16. In Paragraph 13, The above double-sided surface treatment step involves performing a first coating on one side of the aluminum substrate by applying water-based and solvent-based coating solutions using a method that combines direct coating and RKC (Reverse Kiss Coating), and A method for manufacturing a cell pouch film, characterized by including a second coating on the other side of the aluminum substrate, wherein a coating solution is applied using the RKC and Film Up/Down Coating (FiIm up/down coating) method.
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Description

Film for cell pouch with minimized deformation of laminate and method for manufacturing the same This specification relates to a film for a cell pouch with minimized laminate deformation and a method for manufacturing the same. Pouch-type batteries, generally used in electric vehicles and the like, have the advantage of being easy to change shape and having high energy density compared to cylindrical or prismatic batteries. These cell pouches are typically manufactured in the following sequence: a first process of surface treating one side of the metal layer, a second process of surface treating the other side of the metal layer, a third process of laminating an outer layer to one side, and a fourth process of laminating a sealant layer to the other side. During each process, steps such as coating, drying, and winding are repeated. However, this process requires improvement as it increases the probability of process defects and driving losses occurring during material transport. FIG. 1 is a schematic diagram showing a cross-section of a cell pouch film of exemplary embodiments of the present invention. FIG. 2 is a schematic diagram of a manufacturing apparatus for a cell pouch film of exemplary embodiments of the present invention. Figure 3 is a photograph showing a method for evaluating the curl of a cell pouch film before molding in an experimental example of the present invention. Figure 4 is a photograph showing the method for evaluating curl after molding in an experimental example of the present invention. FIG. 5 is a graph schematically illustrating the winding tension (unit N) according to the winding length (unit m) of the example and comparative example in the experimental example of the present invention. FIG. 5a is the example, and FIG. 5b is the comparative example. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the attached drawings. Definition of Terms In this specification, singular expressions may include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and do not exclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. In this specification, expressions such as first and second are used to distinguish configurations from one another, rather than to refer to a specific order, unless otherwise stated. In this specification, the term “cell” means a battery, and has the broadest meaning that includes all types of batteries, such as secondary batteries like lithium-ion batteries and lithium-polymer batteries, and portable storage batteries. In this specification, the terms “cell pouch” or “cell pouch film” refer to a cell component, such as an anode, a cathode, and a separator, that is impregnated with an electrolyte and contained therein. In the broadest sense, this includes all films processed into pouch or box shapes, which have a laminated structure considering gas barrier properties, flexibility, electrolyte resistance, and heat sealability, in order to contain said cell component. In this specification, the term "final structure" refers to the final layer structure of the cell pouch film. This final structure may vary slightly depending on various manufacturing process types. For example, the final structure may consist of an outer cover substrate (or outer layer), a first adhesive layer, an outer surface treatment layer, a reference substrate (or barrier layer), an inner surface treatment layer, a second adhesive layer, and an inner cover substrate (or sealant layer). Alternatively, the final structure may consist of an outer cover substrate (or outer layer), a first adhesive layer, an outer surface treatment layer, a reference substrate (or barrier layer), an inner surface treatment layer, an extrusion coating layer, and an inner cover substrate (or sealant layer). Alternatively, the final structure may consist of an outer cover substrate (or outer layer), a first adhesive layer, an outer surface treatment layer, a reference substrate (or barrier layer), an inner surface treatment layer, a second adhesive layer, an extrusion coating layer, and an inner cover substrate (or sealant layer). In this specification, an intermediate structure refers to a structure formed in the middle of the manufacturing process of a cell pouch film, and various cell pouch intermediate structures may occur depending on the manufacturing process. For example, there may be a first intermediate structure comprising an outer cover substrate (or outer layer), a first adhesive layer (or outer adhesive layer), an outer surface treatment layer, a reference substrate (or barrier layer), an inner surface treatment layer, and a second adhesive layer (or inne