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KR-102963213-B1 - Anode and Method for Manufacturing the Same

KR102963213B1KR 102963213 B1KR102963213 B1KR 102963213B1KR-102963213-B1

Abstract

The present invention provides a cathode that can secure both excellent productivity and long-term reliability by simultaneously preventing manufacturing process defects and the degradation of mechanical properties of the final electrode through an optimized cathode dam composition.

Inventors

  • 최민혁
  • 김국태
  • 김민철
  • 박민구
  • 김상민
  • 문영규

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260511
Application Date
20250718
Priority Date
20240719

Claims (14)

  1. Cathode current collector; A negative active material layer formed on one or both sides of a negative current collector; and A cathode dam formed by drying a composition for a cathode dam comprising inorganic particles, a cellulose-based compound, a rubber-based binder, and additives, which supports both edges in the width direction of a cathode active material layer. The above additive includes a porous additive and a carbon-based material, and The cathode, wherein the content of each component of the above cathode dam composition satisfies (a) to (d) below: (a) Inorganic particles are 50 to 85 parts by weight, (b) 0.5 to 15 parts by weight of a cellulose-based compound, (c) 3 to 20 parts by weight of rubber-based binder, (d) The additive is 5 to 12 parts by weight.
  2. A cathode according to claim 1, wherein the inorganic particles comprise one or more selected from the group consisting of AlO(OH), Al₂O₃ , γ-AlOOH, Al(OH) ₃ , SiO₂ , TiO₂ , SnO₂ , CeO₂ , MgO , NiO , CaO , ZnO, ZrO₂, Y₂O₃ , SrTiO₃, BaTiO₃ , and Mg(OH) ₂ .
  3. The cathode according to claim 1, wherein the cellulose-based compound comprises one or more selected from the group consisting of carboxymethylcellulose, a lithium salt of carboxymethylcellulose, and a sodium salt of carboxymethylcellulose.
  4. A cathode according to claim 1, wherein the weight-average molecular weight (Mw) of the cellulose-based compound is within the range of 100,000 to 600,000.
  5. The cathode according to claim 1, wherein the rubber-based binder comprises one or more selected from the group consisting of styrene-butadiene rubber, acrylate styrene-butadiene rubber, acrylonitrile-butadiene rubber, and acrylonitrile-butadiene-styrene rubber.
  6. delete
  7. The cathode according to claim 1, wherein the additive comprises 0.1 to 0.6 parts by weight of a porous additive and 5 to 10 parts by weight of a carbon-based material.
  8. A cathode according to claim 1, wherein the carbon-based material comprises one or more selected from carbon black, graphite, carbon nanotubes, and carbon nanofibers.
  9. In claim 1, the cathode, wherein the solid content (%) of the composition for the cathode dam is within the range of 10 to 40%.
  10. In claim 1, a cathode having a tensile strength greater than 3 kgf.
  11. Cathode current collector; A negative active material layer formed on one or both sides of the above negative current collector; A cathode dam formed along the edge of the above cathode active material layer; and It includes an overlap portion comprising a first component derived from the above-mentioned cathode active material layer and a second component derived from the cathode dam, and The content of the first component is 40 to 70 parts by weight, and A cathode having a content of 30 to 60 parts by weight of the second component.
  12. Steps for preparing a cathode slurry and a cathode dam composition; and The method includes the step of simultaneously coating a cathode slurry and a cathode dam composition on one or both sides of a cathode current collector, The above-mentioned cathode dam composition comprises inorganic particles, a cellulose-based compound, a rubber-based binder, and additives, and A method for manufacturing a cathode, wherein the content of each component of the above-mentioned cathode dam composition satisfies (a) to (d) below: (a) Inorganic particles are 50 to 85 parts by weight, (b) 0.5 to 15 parts by weight of a cellulose-based compound, (c) 3 to 20 parts by weight of rubber-based binder, (d) The additive is 5 to 12 parts by weight.
  13. A method for manufacturing a cathode according to claim 12, wherein the simultaneous coating is performed by a double die coater.
  14. A method for manufacturing a cathode according to claim 12, wherein the additive comprises 0.1 to 0.6 parts by weight of a porous additive and 5 to 10 parts by weight of a carbon-based material.

Description

Anode and Method for Manufacturing the Same The present invention relates to a cathode and a method for manufacturing a cathode. To reduce dependence on fossil fuels and decrease carbon emissions, the demand for rechargeable batteries capable of repeated use for extended periods is surging. In particular, lithium-ion batteries, which offer superior energy density and lifespan, are being utilized as a core energy source across various sectors, leading to active development of related technologies. Lithium secondary battery electrodes are generally formed by applying a slurry onto a current collector and drying it, but during this process, a 'sliding phenomenon' occurs in which the edges become thin due to the fluidity of the slurry. In the case of the anode, a technology has been partially applied to prevent the slurry from spreading by forming an insulating layer at the edge of the active material layer. However, for the cathode, which lacks a separate insulating layer, a different approach was required, and accordingly, a technology was introduced to form a novel support structure called a 'cathode dam' at the edge of the active material layer. However, this caused other technical challenges. The composition of the cathode dam is a very difficult task that requires considering not only physical properties that simply prevent the spread of the slurry, but also the interaction with the cathode active material layer and processability. Conventional technology had limitations in that it could not simultaneously satisfy these complex requirements. For example, there was a clear trade-off where strengthening certain characteristics of the dam composition resulted in other problems. Attempting to increase the dam's load-bearing capacity lowered the tensile strength of the cathode active material layer, causing electrode detachment, while attempting to improve processability resulted in solution clumping or fat-edge defects caused by excessive verticalization. Conversely, focusing solely on maintaining the physical shape also left the problem of failing to properly suppress sliding phenomena. In conclusion, there is a very high technical demand for a comprehensively optimized cathode dam composition that can overcome all these trade-offs and simultaneously secure excellent productivity and mechanical reliability of the final electrode. FIG. 1 is a partial cross-sectional view showing a cathode according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing an electrode manufacturing apparatus that performs a simultaneous coating process according to one embodiment of the present invention. FIG. 3 is a front view showing an example of a double die coater that can be used as a coating device for the electrode manufacturing device of FIG. 2. FIG. 4 is a front view showing another example of a double die coater that can be used as a coating device for the electrode manufacturing device of FIG. 2. The present invention relates to a cathode. Hereinafter, a cathode according to one embodiment of the present invention will be described in detail with reference to the attached drawings. Additionally, identical or corresponding components are assigned the same or similar reference numbers regardless of drawing symbols, and redundant descriptions thereof are omitted; furthermore, for the convenience of explanation, the size and shape of each illustrated component may be exaggerated or reduced. FIG. 1 is a partial cross-sectional view showing a cathode according to one embodiment of the present invention. For reference, FIG. 1 exemplarily shows a cross-sectional view of a cathode in which a cathode active material layer is provided on one surface of a cathode current collector. Referring to the drawings, the cathode comprises a cathode current collector (100), a cathode active material layer (200) formed on one or both sides of the cathode current collector (100), and a cathode dam (300) formed by drying a cathode dam composition comprising inorganic particles, a cellulose-based compound, a binder, and an additive, which supports both sides of the cathode active material layer (200) in the width direction, and the content of each component of the cathode dam composition satisfies the following (a) to (d): (a) The inorganic particles may be 50 to 85 parts by weight, specifically 55 to 80 parts by weight, 60 to 80 parts by weight, or 70 to 80 parts by weight. (b) The cellulose-based compound may be 0.5 to 15 parts by weight, specifically 1 to 10 parts by weight or 2 to 5 parts by weight. (c) The rubber-based binder may be 3 to 20 parts by weight, specifically 5 to 15 parts by weight or 9 to 14 parts by weight. (d) The additive may be 5 to 12 parts by weight, specifically 6 to 10 parts by weight or 7 to 9 parts by weight. The present invention can ultimately provide a highly reliable cathode by ensuring stability in the manufacturing process and preventing the deterioration of the mechanical propertie