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KR-20260063009-A - SEPARATOR SEALING UNIT AND ELECTRODE ASSEMBLY MANUFACTURED BY THE SAME

KR20260063009AKR 20260063009 AKR20260063009 AKR 20260063009AKR-20260063009-A

Abstract

A separator sealing unit according to an embodiment of the present invention can seal two separator sheets with an electrode in between. The separator sealing unit may include a roll that rotates around a rotation axis; and a plurality of tool tips arranged at regular intervals along the outer surface of the roll and extending parallel to the rotation axis of the roll. Each tool tip may include a plurality of pressing parts that protrude in the radial direction of the roll and are arranged parallel to the rotation axis of the roll to press the separator sheet; and a non-pressing part located between the plurality of pressing parts. At least some of the plurality of tool tips may have the non-pressing parts formed at different locations.

Inventors

  • 김율현
  • 박주휘

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260507
Application Date
20241030

Claims (10)

  1. As a separator sealing unit for sealing two separator sheets with electrodes in between, A roll rotating around a rotation axis; and It includes a plurality of tooltips arranged at regular intervals along the outer surface of the roll and extending parallel to the rotation axis of the roll, Each of the above tooltips is, A plurality of pressure members protruding in the radial direction of the roll and arranged parallel to the rotation axis of the roll to press the separator sheet; and It includes a non-pressurized portion located between the plurality of pressurized portions mentioned above, and At least some of the above plurality of tooltips are separator sealing units in which the above-mentioned unpressurized portions are formed at different locations.
  2. In Article 1, A separator sealing unit in which the unpressurized portion of one tool tip and the unpressurized portion of another tool tip among the plurality of tool tips are at least partially non-overlapping with respect to the circumferential direction of the roll.
  3. In Article 1, A separator sealing unit in which the position of the unpressurized portion moves in a direction parallel to the rotation axis of the roll as it moves in the circumferential direction of the roll.
  4. In an electrode assembly in which a plurality of unit cells are stacked, wherein a first separator, a first electrode, a second separator, and a second electrode are sequentially laminated, Each unit cell is, The edge portions of the first and second separators are formed by sealing, and a plurality of sealing portions are formed at a predetermined interval from each other along the extension direction of the edge portions; It includes unsealed portions located between the plurality of sealing portions and facing each other without sealing the first and second separators, At least some of the plurality of unit cells are electrode assemblies in which the unsealed portions are formed at different locations.
  5. In Article 4, An electrode assembly in which the unsealed portion of one unit cell and the unsealed portion of another unit cell among the plurality of unit cells are at least partially non-overlapping with respect to the stacking direction of the plurality of unit cells.
  6. In Article 4, The above-mentioned sealing portion and unsealing portion are electrode assemblies located on the long side of each unit cell.
  7. In Article 4, In each of the above unit cells, the location of the unsealed portion located on one long side and the location of the unsealed portion located on the other long side are different electrode assemblies.
  8. In Article 4, The above plurality of unit cells are divided into a plurality of stacked groups, and An electrode assembly in which, within each group, the position of the unsealed portion moves to one side as the stacking direction of the plurality of unit cells increases.
  9. In Article 4, It further includes a fixing member surrounding the plurality of unit cells, and The above-mentioned fixed member is an electrode assembly that covers the sealing portion to form a predetermined gap with the above-mentioned unsealed portion.
  10. In Article 9, Each of the above unit cells includes a plurality of unsealed parts, and The above-mentioned fixing member is an electrode assembly that crosses between the plurality of unsealed portions.

Description

Separator sealing unit and electrode assembly manufactured by the same The present invention relates to a sealing unit for joining a first separator sheet and a second separator sheet with an electrode in between, and an electrode assembly manufactured thereby. Generally, types of secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and lithium-ion polymer batteries. These secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and E-bikes, but also in large products requiring high output such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated power or renewable energy. To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to produce a positive electrode and a negative electrode, and then an electrode assembly of a predetermined shape is formed by stacking them on both sides of a separator. Then, the electrode assembly is placed in a battery case, and after injecting an electrolyte, it is sealed. Electrode assemblies are classified into various types. For example, there are the Simple Stack Type, in which anodes, separators, and cathodes are simply stacked alternately without manufacturing unit cells; the Lamination & Stack Type (L&S), in which unit cells are manufactured first using anodes, separators, and cathodes, and then these unit cells are stacked; the Stack & Folding Type (S&F), in which multiple electrodes or unit cells are attached spaced apart on one side of a separator sheet that is long on one side, and the separator sheet is repeatedly folded in the same direction from one end; and the Z-Folding Type, in which multiple electrodes or unit cells are alternately attached to one side and the other side of a separator sheet that is long on one side, and the method of folding the separator sheet in a specific direction from one end and then folding it in the opposite direction is repeated alternately. Among these, to manufacture a lamination-and-stack type, stack-and-fold type, or Z-fold type electrode assembly, a unit cell can be manufactured first. Generally, a unit cell is manufactured by laminating and cutting a laminate in which a separator sheet is laminated on the upper and lower surfaces of the electrode, respectively. Additionally, depending on the case, an upper electrode may be further laminated at the top of the laminate and/or a lower electrode at the bottom. Conventionally, in order to prevent separator folding and improve the stability of the unit cell, a process was performed to bond the edges of two separator sheets with an electrode in between. However, in the case of electrode assemblies manufactured by stacking such unit cells, gases generated during charging, discharging, or long-term use of the electrode assembly may not be smoothly discharged due to the sealing between the separator sheets. Consequently, there was a concern that gases could be trapped inside the electrode assembly, leading to lithium precipitation or a decrease in battery lifespan and performance. The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. Figure 1 is a schematic diagram of a battery cell manufacturing system. Figure 2 is a diagram for explaining the operation of the membrane sealing unit illustrated in Figure 1. FIG. 3 is a perspective view of a membrane sealing unit according to an embodiment of the present invention. FIG. 4 is a perspective view of a membrane sealing unit according to a comparative example. FIG. 5 is a perspective view of an electrode assembly according to an embodiment of the present invention. FIG. 6 is a cross-sectional view schematically illustrating the stacking of unit cells during the process of manufacturing the electrode assembly of FIG. 5. Figure 7 is a front view of the electrode assembly shown in Figure 5. FIG. 8 is a front view of an electrode assembly according to a comparative example. Hereinafter, preferred 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. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments. In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unn