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KR-102963894-B1 - Lithium secondary battery and method of manufacturing the same

KR102963894B1KR 102963894 B1KR102963894 B1KR 102963894B1KR-102963894-B1

Abstract

The present invention provides a method for manufacturing a lithium secondary battery with high energy density. The invention relates to a method for manufacturing a lithium secondary battery comprising a positive electrode, a negative electrode not having a negative electrode active material, and a separator, comprising the steps of applying a gel electrolyte to one side of the separator and forming the negative electrode on the surface of the gel electrolyte, wherein the negative electrode is thinner than the gel electrolyte.

Inventors

  • 아라이, 주이치
  • 오가타, 켄

Assignees

  • 테라와트 테크놀로지 가부시키가이샤

Dates

Publication Date
20260512
Application Date
20210128

Claims (20)

  1. A method for manufacturing a lithium secondary battery comprising a positive electrode, a negative electrode selected from the group consisting of at least one material that does not have a negative electrode active material and is composed of Cu, Ni, Ti, Fe, other metals that do not react with Li, alloys thereof, and stainless steel (SUS), and a separator, A process of applying a gel electrolyte to one side of the above separator, and The method includes a process of forming the cathode on the surface of the gel electrolyte, The above cathode is thinner than the gel electrolyte, Method for manufacturing a lithium secondary battery.
  2. In paragraph 1, A method for manufacturing a lithium secondary battery, wherein the thickness of the above-mentioned negative electrode is 0.5㎛ or more and 6㎛ or less.
  3. In paragraph 1 or 2, A method for manufacturing a lithium secondary battery, wherein the gel electrolyte comprises at least one selected from the group consisting of polyethylene oxide, polypropylene oxide, polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, chlorotrifluoroethylene-ethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, and derivatives thereof.
  4. In paragraph 1 or 2, A method for manufacturing a lithium secondary battery, wherein the gel electrolyte comprises, as a solvent, a compound having at least one of a monovalent group represented by the following formula (A) and a monovalent group represented by the following formula (B). [Chemical Formula 1] [Chemical Formula 2] In the above equation, the wavy line represents the bonding site of the 1 group.
  5. In paragraph 1 or 2, A method for manufacturing a lithium secondary battery, wherein the thickness of the gel electrolyte is 6㎛ or more and 15㎛ or less.
  6. In paragraph 1 or 2, A method for manufacturing a lithium secondary battery, wherein the process of forming the above-mentioned cathode comprises a process of attaching a cathode material having a release liner to the surface of the above-mentioned gel electrolyte and a process of removing the release liner.
  7. In paragraph 1 or 2, A method for manufacturing a lithium secondary battery, wherein the process of forming the above-mentioned cathode is a process of forming the cathode on the surface of the gel electrolyte by deposition or plating.
  8. In paragraph 1 or 2, A method for manufacturing a lithium secondary battery, further comprising the process of forming the positive electrode by applying a positive electrode material containing the above-mentioned gel electrolyte to the other side of the above-mentioned separator.
  9. In paragraph 8, A method for manufacturing a lithium secondary battery, further comprising a process of forming a positive current collector with a thickness of 1.0 μm or more and 6.0 μm or less on the surface of the positive electrode.
  10. In Paragraph 9, A method for manufacturing a lithium secondary battery, wherein the process of forming the positive current collector comprises a process of attaching a positive current collector material having a release liner to the surface of the positive electrode and a process of removing the release liner.
  11. In Paragraph 9, A method for manufacturing a lithium secondary battery, wherein the process of forming the positive current collector is a process of forming the positive current collector on the surface of the positive electrode by deposition or plating.
  12. In paragraph 1 or 2, A method for manufacturing a lithium secondary battery having an energy density of 500 Wh/kg or more.
  13. A lithium secondary battery comprising a positive electrode, a negative electrode selected from the group consisting of at least one material that does not have a negative electrode active material and is composed of Cu, Ni, Ti, Fe, other metals that do not react with Li, alloys thereof, and stainless steel (SUS), and a separator, A gel electrolyte is applied to one side of the above separator, and The cathode is formed on the surface of the gel electrolyte, and The above cathode is thinner than the gel electrolyte, Lithium secondary battery.
  14. In Paragraph 13, A lithium secondary battery having a negative electrode thickness of 0.5㎛ or more and 6.0㎛ or less.
  15. In paragraph 13 or 14, A lithium secondary battery comprising at least one selected from the group consisting of polyethylene oxide, polypropylene oxide, polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, chlorotrifluoroethylene-ethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, and derivatives thereof.
  16. In paragraph 13 or 14, A lithium secondary battery comprising, as a solvent, a compound having at least one of a monovalent group represented by the following formula (A) and a monovalent group represented by the following formula (B). [Chemical Formula 3] [Chemical Formula 4] In the above equation, the wavy line represents the bonding site of the 1 group.
  17. In paragraph 13 or 14, A lithium secondary battery having a gel electrolyte thickness of 6㎛ or more and 15㎛ or less.
  18. In paragraph 13 or 14, A lithium secondary battery in which an anode containing the above-mentioned gel electrolyte is formed on the other side of the above-mentioned separator.
  19. In Paragraph 18, A lithium secondary battery comprising, on a positive electrode containing the above-mentioned gel electrolyte, an additional positive electrode current collector having a thickness of 1.0 μm or more and 6.0 μm or less.
  20. In paragraph 13 or 14, A lithium secondary battery with an energy density of 500 Wh/kg or higher.

Description

Lithium secondary battery and method of manufacturing the same The present invention relates to a lithium secondary battery and a method for manufacturing the same. Recently, technologies for converting natural energy, such as solar or wind power, into electrical energy have been attracting attention. Accordingly, various secondary batteries are being developed as energy storage devices that offer high safety and can store large amounts of electrical energy. Among them, secondary batteries that perform charging and discharging through the movement of metal ions between the positive and negative electrodes are known to exhibit high voltage and high energy density. A typical lithium-ion secondary battery is a lithium secondary battery that utilizes active materials capable of retaining lithium elements in the positive and negative electrodes, and performs charging and discharging by exchanging lithium ions between the positive and negative active materials. In addition, to achieve high energy density, lithium secondary batteries are being developed that utilize lithium metal rather than materials capable of inserting lithium elements, such as carbon-based materials, into the negative electrode active material. For example, Patent Document 1 discloses a lithium secondary battery having a lithium metal anode with a thickness of about 10 μm to 20 μm to achieve a volume energy density exceeding 1000 Wh/L and/or a mass energy density exceeding 350 Wh/kg during discharge at a rate of at least 1 C at room temperature. Patent Document 1 discloses that in such a lithium secondary battery, charging is achieved by directly depositing more lithium metal onto the lithium metal as the negative electrode active material. In addition, lithium secondary batteries that do not use negative electrode active materials are being developed to achieve higher energy density or improve productivity. For example, Patent Document 2 discloses a lithium secondary battery comprising a positive electrode, a negative electrode, a separator interposed between them, and an electrolyte, wherein the negative electrode has metal particles formed on a negative electrode current collector, which are moved from the positive electrode by charging and form lithium metal on the negative electrode current collector within the negative electrode. Patent Document 2 discloses that such a lithium secondary battery can provide a lithium secondary battery with improved performance and lifespan by solving problems caused by the reactivity of lithium metal and problems occurring during the assembly process. FIG. 1 is a schematic cross-sectional view of a lithium secondary battery according to the first embodiment. Figure 2 is a flowchart illustrating a method for manufacturing the above-mentioned lithium secondary battery. Figure 3 is a schematic cross-sectional view of the above-mentioned lithium secondary battery usage. FIG. 4 is a schematic cross-sectional view of a lithium secondary battery according to the second embodiment. Embodiments of the present invention (hereinafter referred to as "the present embodiment") are described in detail below with reference to the drawings as necessary. Identical elements in the drawings are denoted by the same reference numerals, and redundant descriptions have been omitted. Furthermore, positional relationships, such as up, down, left, and right, are based on the positional relationships shown in the drawings unless otherwise noted. Additionally, the dimensional ratios in the drawings are not limited to the ratios shown in the drawings. [First embodiment] (Lithium secondary battery) FIG. 1 is a schematic cross-sectional view of a lithium secondary battery (100) according to the first embodiment. The lithium secondary battery (100) comprises a negative electrode (110) that does not have a negative electrode active material, a gel electrolyte (120), a separator (130), a positive electrode (140), and a positive current collector (150). The negative electrode (110) and the positive electrode (140) are arranged to face each other with the separator (130) in between. The gel electrolyte (120) is disposed between the separator (130) and the negative electrode (110). That is, the gel electrolyte (120) is disposed on one side of the separator (130), and the positive electrode (140) is disposed on the other side of the separator (130). First, details of each component will be described. (cathode) The negative electrode (110) does not have a negative electrode active material. That is, the negative electrode (110) does not have lithium or an active material that serves as a host for lithium. Therefore, compared to a lithium secondary battery having a negative electrode with a negative electrode active material, the lithium secondary battery (100) has a smaller overall volume and mass and, in principle, a higher energy density. Here, in the lithium secondary battery (100), charging and discharging are achieved by precipitating lith