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EP-4262012-B1 - LITHIUM SECONDARY BATTERY INTO WHICH ELECTROLYTIC SOLUTION CAN BE ADDITIONALLY INJECTED

EP4262012B1EP 4262012 B1EP4262012 B1EP 4262012B1EP-4262012-B1

Inventors

  • LEE, HAN YOUNG

Dates

Publication Date
20260513
Application Date
20221123

Claims (14)

  1. A lithium secondary battery (100) accommodating an electrode assembly (10) and a main electrolyte (15) inside a battery case (60) comprising: an electrolyte replenishing unit (40) filled with a preliminary electrolyte (45) inside a packaging member (41), characterized in that the lithium secondary battery further comprises a rupture member (50) disposed adjacent to the electrolyte replenishing unit (40) and deformed by a temperature change to form a hole in the packaging member (41) so that the preliminary electrolyte (45) inside the electrolyte replenishing unit (40) can be injected, wherein the electrolyte replenishing unit (40) and the rupture member (50) are disposed in a separation space between the electrode assembly (10) and the battery case (60).
  2. The lithium secondary battery (100) of claim 1, wherein the packaging member (41) is a pouch-type form made of a thermoplastic synthetic resin film.
  3. The lithium secondary battery (100) of claim 2, wherein the packaging member (41) is made of a polyethylene resin film.
  4. The lithium secondary battery (100) of claim 1, wherein the electrolyte replenishing unit (40) and the rupture member (50) are disposed adjacent to an upper surface or a lower surface of the battery case (60) by being stacked on the electrode assembly (10).
  5. The lithium secondary battery (100) of claim 1, wherein the electrolyte replenishing unit (40) and the rupture member (50) are disposed in a sidewall of the battery case (60) of a dead space (A) near an end of the electrode assembly (10).
  6. The lithium secondary battery (100) of any one of claim 1 to claim 5, wherein the rupture member (50) is disposed between the electrolyte replenishing unit (40) and the battery case (60).
  7. The lithium secondary battery (100) of claim 1, wherein the rupture member (50) is thermally deformed at a temperature of 80°C to 120°C.
  8. The lithium secondary battery (100) of claim 1, wherein the rupture member (50) is a shape-memory alloy.
  9. The lithium secondary battery (100) of claim 1, wherein the rupture member (50) is a bimetal.
  10. The lithium secondary battery (100) of claim 1, wherein the rupture member (50) is bonded to the electrolyte replenishing unit (40), and a weak part is formed in the packaging member (41) along an edge direction of the rupture member (50).
  11. The lithium secondary battery (100) of claim 1, wherein the preliminary electrolyte (45) does not comprise an additive for a SEI film formation.
  12. The lithium secondary battery (100) of claim 1, wherein the battery case (60) is a cylindrical metal can or a prismatic metal can.
  13. An lithium secondary battery electrolyte replenish method comprises applying heat to the lithium secondary battery (100) of claim 1 to cause thermal deformation in the rupture member (50).
  14. The lithium secondary battery electrolyte replenish method of claim 13, wherein the temperature at which heat is applied to the rupture member (50) is 80°C to 120°C.

Description

[Technical Field] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0163410 filed on November 24, 2021. The present invention relates to a lithium secondary battery capable of an additional injection of electrolyte. [Background Technology of the Invention] In general, a lithium secondary battery has a structure in which a separator is interposed between a positive electrode and a negative electrode as power generation elements, and a liquid electrolyte is injected between the power generation elements. A pouch-type battery that is commonly used is manufactured by accommodating an electrode assembly composed of a positive electrode/a separator/a negative electrode in a pouch-type battery case formed by a laminate sheet made of a polymer resin and an aluminum, coupling the upper laminate sheet to the lower laminate sheet in a state in which electrode leads are exposed to both ends of the battery case, and sealing through heat-compression. Meanwhile, when the secondary battery is continuously charged and discharged, an electrolyte causes side reactions to bring denaturation, and the electrolyte inside the battery becomes insufficient, thereby reducing the lifespan of the secondary battery. Since a cell case of a prismatic or a cylindrical lithium-ion secondary battery is made of a metallic material, the cell should be disassembled to inject an additional electrolyte. Due to cell disassembly, an electrode is oxidized in some cases when exposed to air, and there is a disadvantage in that it is difficulty to reseal after an additional injection. In order to replenish the electrolyte without disassembling the battery, KR 10-2018-0023706 A discloses a technology including a sealing member for additional electrolyte injection formed on a part of a battery case, so that an additional injection can be performed and a portion of injection can be sealed after injecting the electrolyte into the electrolyte accommodating part of the battery case, but there are disadvantages in that the assembly process of the battery is complicated due to the sealing member, and that the electrolyte has to be injected for each battery. Therefore, there is a need to develop a technology capable of additionally supplying an insufficient electrolyte in a safer and a more convenient way. Further prior art is described in US 10 916 820 B2 and US 8 652 668 B2. [Description of the Invention] [Technical Problem] The present invention is to solve the above conventional problems, and in order to extend the lifespan of the secondary battery, the present invention is directed to provide a lithium-ion secondary battery having a novel structure capable of supplying an additional electrolyte when a cell becomes degraded. [Technical Solution] To achieve the above purpose, the lithium secondary battery according to an exemplary embodiment of the present invention includes: an electrolyte replenishing unit filled with a preliminary electrolyte inside a packaging member; and a rupture member disposed adjacent to the electrolyte replenishing unit and deformed by a temperature change to form a hole in the packaging member so that the preliminary electrolyte inside the electrolyte replenishing unit can be injected, wherein the electrolyte replenishing unit and the rupture member are disposed in a separation space between the electrode assembly and the battery case. In the lithium secondary battery according to an exemplary embodiment of the present invention, the packaging member may be a pouch-type made of a thermoplastic synthetic resin film. In the lithium secondary battery according to an exemplary embodiment of the present invention, the packaging member may be made of a polyethylene resin film. In the lithium secondary battery according to an exemplary embodiment of the present invention, the electrolyte replenishing unit and the rupture member may be disposed adjacent to an upper surface or a lower surface of the battery case by being stacked on the electrode assembly. In the lithium secondary battery according to an exemplary embodiment of the present invention, the electrolyte replenishing unit and the rupture member may be disposed in a sidewall of the battery case of a dead space near the end of the electrode assembly. In the lithium secondary battery according to an exemplary embodiment of the present invention, the rupture member may be disposed between the electrolyte replenishing unit and the battery case. In the lithium secondary battery according to an exemplary embodiment of the present invention, the rupture member may be thermally deformed at a temperature of 80°C to 120°C. In the lithium secondary battery according to an exemplary embodiment of the present invention, the rupture member may be a shape-memory alloy. In the lithium secondary battery according to an exemplary embodiment of the present invention, the rupture member may be a bimetal. In the lithium secondary battery according to an ex