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KR-20260067499-A - release film for transcribing lithium and method for manufacturing thereof

KR20260067499AKR 20260067499 AKR20260067499 AKR 20260067499AKR-20260067499-A

Abstract

The present invention relates to a lithium transfer release film and a method for manufacturing the same. More specifically, the invention relates to a release film for transferring lithium (Li) to a current collector of a battery after depositing lithium (Li) on the release film, wherein the deposition efficiency is excellent by minimizing the occurrence of pinholes when depositing lithium (Li) on the release film, and the lithium transfer release film and a method for manufacturing the same are excellent.

Inventors

  • 장남윤
  • 김용규
  • 김재용
  • 전승환
  • 편정민
  • 한은정
  • 황보격

Assignees

  • 율촌화학 주식회사

Dates

Publication Date
20260513
Application Date
20241105

Claims (17)

  1. A second barrier layer; a base film; a first barrier layer; and a release layer; wherein the above are sequentially laminated as a lithium transfer release film, A lithium transfer release film characterized by the fact that, after depositing lithium to a thickness of 2 to 25 μm on one surface of the release layer, white light is irradiated onto the second barrier layer, and the number of pinholes in the deposited lithium is 100 or fewer per unit area of 10 cm x 10 cm.
  2. In paragraph 1, The above release layer comprises a resin composition, and A lithium transfer release film characterized by the above resin composition containing 10 to 70 weight percent of a silicone-based resin based on the total weight percent.
  3. In paragraph 2, A lithium transfer release film characterized by the above release layer comprising 0.1 to 5 parts by weight of a catalyst and 0.1 to 5 parts by weight of an adhesion enhancer per 100 parts by weight of a resin composition.
  4. In paragraph 1, A lithium transfer release film characterized by the above release layer containing 2 to 5 weight percent of silicon (Si) based on the total weight percent.
  5. In paragraph 1, A lithium transfer release film characterized in that each of the first barrier layer and the second barrier layer comprises one or more selected from aluminum (Al), aluminum oxide ( Al₂O₃ ), silicon oxide (SiOx), silicon nitride (SiNx), PVDC (Polyvinylidene Chloride), EVOH (ethylene-vinyl alcohol copolymer), and PVA (Polyvinyl Alcohol).
  6. In paragraph 1, A lithium transfer release film characterized by the above base film comprising one or more selected from PET (Polyethylene terephthalate), PP (Polypropylene), PBT (Polybutyleneterephthalate), PEN (Polyethylene naphthalate), PI (Polyimide), and PE (Polyethylene).
  7. In paragraph 2, The above resin composition includes a silicone-based resin and a non-silicone-based resin, and The above silicone-based resin comprises one or more types selected from addition-reaction type silicone-based resins, condensation-reaction type silicone-based resins, and UV-reaction type silicone-based resins, and A lithium transfer release film characterized by comprising one or more types selected from cellulose resin, acrylate resin, melamine resin, and alkyd resin.
  8. In paragraph 1, The above base film and the first barrier layer have a thickness ratio of 1:0.001 to 0.003, and The above base film and second barrier layer have a thickness ratio of 1:0.001 to 0.003, and A lithium transfer release film characterized in that the base film and the release layer have a thickness ratio of 1:0.003 to 0.005.
  9. A lithium transfer release film having a barrier layer; a base film; and a release layer sequentially laminated therein, A lithium transfer release film characterized by the fact that, after depositing lithium to a thickness of 2 to 25 μm on one surface of the release layer, white light is irradiated onto the barrier layer, and the number of pinholes in the deposited lithium is 100 or fewer per unit area of 10 cm x 10 cm.
  10. A lithium transfer release film having a base film; a barrier layer; and a release layer sequentially laminated therein, A lithium transfer release film characterized by the fact that, after depositing lithium to a thickness of 2 to 25 μm on one surface of the release layer, when white light is irradiated onto the base film, 100 or fewer pinholes occur per unit area of 10 cm x 10 cm in the deposited lithium.
  11. A second release layer; a barrier layer; a base film; and a first release layer; wherein the above are sequentially laminated as a lithium transfer release film, A lithium transfer release film characterized by the fact that, after depositing lithium to a thickness of 2 to 25 μm on one surface of the first release layer, white light is irradiated onto the second release layer, resulting in 100 or fewer pinholes per unit area of 10 cm x 10 cm occurring in the deposited lithium.
  12. A second release layer; a base film; a barrier layer; and a first release layer; wherein the above are sequentially laminated as a lithium transfer release film, A lithium transfer release film characterized by the fact that, after depositing lithium to a thickness of 2 to 25 μm on one surface of the first release layer, white light is irradiated onto the second release layer, resulting in 100 or fewer pinholes per unit area of 10 cm x 10 cm occurring in the deposited lithium.
  13. In paragraph 1, A lithium transfer release film characterized by the fact that, after depositing lithium to a thickness of 2 to 8 μm on one surface of the release layer, white light is irradiated onto the second barrier layer, resulting in 100 or fewer pinholes per unit area of 10 cm x 10 cm occurring in the deposited lithium.
  14. Step 1: Preparing the base film; A second step of forming a first barrier layer on one surface of the base film and forming a second barrier layer on the other surface of the base film, respectively; and A third step of forming a release layer by applying a composition for forming a release layer to one surface of the first barrier layer and then curing it; comprising A method for manufacturing a lithium transfer release film characterized by depositing lithium to a thickness of 2 to 25 μm on one surface of the release layer, and then irradiating the second barrier layer with white light, such that 100 or fewer pinholes occur per unit area of 10 cm x 10 cm in the deposited lithium.
  15. In Paragraph 14, The above-mentioned composition for forming a release layer is a mixture of a resin composition, a catalyst, an adhesion enhancer, and a solvent, and A method for manufacturing a lithium transfer release film, characterized in that the resin composition comprises 10 to 70 weight percent of a silicone-based resin mixed with respect to the total weight percent.
  16. In paragraph 15, A method for manufacturing a lithium transfer release film, characterized in that the above-mentioned composition for forming a release layer is mixed with 0.1 to 5 parts by weight of a catalyst, 0.1 to 5 parts by weight of an adhesion enhancer, and 800 to 2000 parts by weight of a solvent, based on 100 parts by weight of a resin composition.
  17. In Paragraph 14, A method for manufacturing a lithium transfer release film, characterized by performing the above curing at a temperature of 100 to 140℃ for 10 to 40 seconds.

Description

Release film for transcribing lithium and method for manufacturing thereof The present invention relates to a lithium transfer release film and a method for manufacturing the same. More specifically, the invention relates to a release film for transferring lithium (Li) to a current collector of a battery after depositing lithium (Li) on the release film, wherein the deposition efficiency is excellent by minimizing the occurrence of pinholes when depositing lithium (Li) on the release film, and the lithium transfer release film and a method for manufacturing the same are excellent. In batteries, specifically secondary batteries, the battery capacity is reduced compared to the theoretical capacity of the anode material because a large proportion of the lithium ions released from the positive electrode during the first charge remain adsorbed on the negative electrode. To avoid such irreversible capacity loss, a technique has been disclosed in which lithium equivalent to the irreversible capacity loss is adsorbed on the negative electrode in advance, and then the secondary battery is assembled and charging and discharging are initiated. By utilizing this technique, a high proportion of lithium ions released from the positive electrode during the first charge can be recovered to the negative electrode, thereby increasing the battery capacity. Meanwhile, as a common method for pre-absorbing lithium onto the cathode, a method of depositing lithium onto the cathode is being used. In order to deposit lithium equivalent to an irreversible capacity, a method is being studied to increase the amount of lithium deposited by pre-treating a graphite material or a silicon graphite material onto a current collector. However, graphite materials have a capacity limit when lithium ions move, and silicon graphite materials are highly likely to cause problems with battery durability due to rapid volume expansion during lithium ion movement. For this reason, there is a need to develop a new method to pre-charge a sufficient amount of lithium into the cathode and/or prevent volume expansion due to an increase in the amount of lithium, and as one such method, a method is being attempted in which lithium metal is deposited on a release film and then transferred to a current collector, preferably a cathode current collector. In conclusion, regarding the method of depositing lithium on a release film and then transferring it to a current collector, there is a need for measures to ensure uniform lithium deposition and high transfer efficiency. FIG. 1 is a cross-sectional view showing a lithium transfer release film on one side according to a preferred embodiment of the present invention. FIG. 2 is a schematic diagram showing the observation of pinholes occurring in the deposited lithium after depositing lithium on one surface of a release layer according to a preferred embodiment of the present invention and then irradiating a second barrier layer with white light. FIG. 3 is a cross-sectional view showing a lithium transfer release film on one side according to another preferred embodiment of the present invention. FIG. 4 is a cross-sectional view showing a lithium transfer release film on one side according to another preferred embodiment of the present invention. FIG. 5 is a cross-sectional view showing a lithium transfer release film on one side according to another preferred embodiment of the present invention. FIG. 6 is a cross-sectional view showing a lithium transfer release film on one side according to another preferred embodiment of the present invention. Hereinafter, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, parts unrelated to the explanation have been omitted to clearly explain the present invention, and the same reference numerals are assigned to identical or similar components throughout the specification. Referring to FIG. 1, the lithium transfer release film of the present invention may be formed by sequentially laminating a second barrier layer (22), a base film (10), a first barrier layer (21), and a release layer (30). The base film (10) is a film that serves as a substrate film when coating the release layer (30) or depositing lithium (Li), and any base film material used in the industry can be used, preferably it may include one or more selected from PET (Polyethylene terephthalate), PP (Polypropylene), PBT (Polybutylene terephthalate), PEN (Polyethylene naphthalate), PI (Polyimide), and PE (Polyethylene), and more preferably it may include PET. In addition, the base film (10) of the present invention may have a thickness of 10 to 250 μm, preferably 25 to 100 μm. If the thickness is less than 10 μm, there may be a problem of thermal deformation o