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KR-102963879-B1 - Pouch-type Battery Cell and Method for Manufacturing the Same

KR102963879B1KR 102963879 B1KR102963879 B1KR 102963879B1KR-102963879-B1

Abstract

The present invention relates to a pouch-type battery cell comprising an electrode assembly, a battery case having a storage portion and a gas collection portion formed therein for accommodating the electrode assembly, and an opening/closing portion attached to the gas collection portion for discharging gas inside the battery case, and a method for manufacturing the same, wherein the outer surface of the gas collection portion can be prevented from being contaminated by the electrolyte during the degassing process.

Inventors

  • 정주영
  • 정수택

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260511
Application Date
20200805

Claims (12)

  1. Electrode assembly; A battery case having a storage section and a gas collection section formed therein for accommodating the above electrode assembly; and An opening/closing part attached to the above gas collection part and for discharging gas inside the battery case; Includes, The above opening and closing part is, A coupling part coupled to the gas collection part of the battery case above; A gas exhaust portion extending upward from the above-mentioned joint portion; and A pouch-type battery cell comprising a plug portion located at the inner end of the gas exhaust portion.
  2. In claim 1, the battery case comprises a first case and a second case that are heat-fused to each other at the outer periphery, and The above first case and second case are pouch-type battery cells having gas collection portions formed in the same shape at the same location.
  3. In claim 2, the gas collection part is a pouch-type battery cell formed with a stepped structure protruding in two stages.
  4. In claim 2, the gas collecting portion is a pouch-type battery cell having a structure that protrudes in a trapezoidal shape, becoming narrower as it moves away from the storage portion.
  5. delete
  6. In claim 1, the opening/closing portion is a pouch-type battery cell composed of a first polymer resin layer, a metal layer, and a second polymer resin layer.
  7. A pouch-type battery cell according to claim 6, wherein the first polymer resin layer and the second polymer resin layer are polypropylene, and the metal layer is aluminum.
  8. In claim 1, the coupling portion is coupled in a form inserted into the inner side of the gas collection portion, forming a pouch-type battery cell.
  9. A pouch-type battery cell according to claim 1, wherein gas is discharged as the plug portion opens when a vacuum hose is inserted into the gas exhaust portion.
  10. A method for manufacturing a pouch-type battery cell according to any one of claims 1 to 4 and claims 6 to 9, (a) A step of manufacturing a first case and a second case by forming a storage section and a gas collection section on a laminate sheet; (b) A step of connecting an opening/closing part to the gas collection part; (c) a step of manufacturing a pouch-type battery cell by housing an electrode assembly in the above-mentioned storage portion and sealing the outer periphery of the first case and the second case; (d) a step of activating the above pouch-type battery cell; and (e) a step of discharging gas inside the pouch-type battery cell; A method for manufacturing a pouch-type battery cell including
  11. A method for manufacturing a pouch-type battery cell according to claim 10, wherein step (e) proceeds as a process in which gas is discharged as the plug part is opened when a vacuum hose is inserted into the opening/closing part.
  12. A method for manufacturing a pouch-type battery cell according to claim 10, wherein the gas collection unit is formed in the same shape at a position where the first case and the second case face each other.

Description

Pouch-type Battery Cell and Method for Manufacturing the Same The present invention relates to a pouch-type battery cell and a method for manufacturing said pouch-type battery cell. Specifically, it relates to a pouch-type battery cell capable of discharging internal gas using a gas collection unit attached to a battery case, and a method for manufacturing said pouch-type battery cell. Rechargeable lithium secondary batteries are widely used as energy sources for wireless mobile devices or wearable devices worn on the body, as well as for electric vehicles and hybrid electric vehicles, which are presented as alternatives to conventional gasoline and diesel vehicles that cause air pollution. The above-mentioned lithium secondary batteries can be classified into prismatic and cylindrical battery cells containing metal can-type cases, and pouch-type battery cells containing cases formed from laminate sheets; among these, pouch-type battery cells are widely used due to their advantages of easy shape deformation and the ability to increase energy density during storage and stacking. A general method for manufacturing a pouch-type battery cell comprises a packaging process in which an electrode assembly is placed in a pouch together with an electrolyte, a formation process, a degassing process, and an aging process in which the packaged battery cell is aged for a certain period of time, and in some cases, the formation process and the degassing process may be performed two or more times. To carry out the above degassing process, a portion of the battery cell placed in the vacuum chamber is cut open, and the interior of the vacuum chamber is depressurized so that the gas inside the battery cell is discharged into the vacuum chamber. In order to perform the degassing process using a vacuum chamber in this manner, the entire interior space of the vacuum chamber must be depressurized to a predetermined vacuum pressure; however, this process presents the problem of requiring high costs. As another example of the above degassing process, a gas outlet can be created in the battery cell using a knife or the like, a vacuum pad connected to a vacuum line can be attached to the gas outlet, and the gas can be removed using vacuum pressure. However, when using such a degassing process, there is a problem in that the gas exhaust passage of the battery cell narrows due to the instantaneous vacuum pressure, preventing the gas present inside the battery cell from being completely discharged. In addition, in the absence of a separate gas collection unit, the upper and lower parts of the pouch-type battery case become more tightly sealed due to reduced pressure, making it difficult to secure a passage for gas to travel from the electrode assembly housing to the vacuum pad. Accordingly, Patent Document 1 discloses a pouch comprising a first receiving portion in which an electrode assembly is received and a second receiving portion in which gas generated in the first receiving portion is collected, and discloses a gas removal device comprising a vacuum pump for generating vacuum pressure, a buffer tank for maintaining a constant vacuum pressure, a throttle valve for regulating and supplying vacuum pressure, a vacuum pad for sucking gas and electrolyte from the pouch, and a controller for controlling a vacuum gauge and the opening amount of the throttle valve. The above patent document 1 discloses a function that sucks up gas collected in the second receiving portion by vacuum pressure applied to the pouch, and at the same time sucks up the electrolyte that is over-injected into the first receiving portion, but fails to prevent the electrolyte from being discharged along with the gas discharge. Patent Document 2 discloses a first degassing step in which a first vacuum pad and a second vacuum pad are respectively placed on one side and the other side of a pouch extension, and after perforating a gas hole in the extension, the internal gas of the secondary battery is vacuum-suctioned and discharged to the outside using the first vacuum pad and the second vacuum pad. As described in Patent Document 2 above, when vacuum suction is performed into the vacuum pad through a gas hole formed in the extension, there is a problem that the internal space of the vacuum pad may be contaminated with electrolyte. Therefore, there is a high need for a technology that can not only prevent the electrolyte in the electrode assembly housing from being discharged along with gas during the degassing process of a pouch-type battery cell, but also prevent the internal space of the vacuum pad from being contaminated with the electrolyte. FIG. 1 is a perspective view of a pouch-type battery cell according to one embodiment. FIG. 2 is a perspective view of a pouch-type battery cell according to another embodiment. FIG. 3 is a side view of the pouch-type battery cells shown in FIG. 1 and FIG. 2. FIG. 4 is a perspective view of an opening and closing part according