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EP-4742311-A1 - ELECTRODE AND SECONDARY BATTERY

EP4742311A1EP 4742311 A1EP4742311 A1EP 4742311A1EP-4742311-A1

Abstract

The present invention relates to an electrode (200), and a technical problem to be solved is to provide an electrode (200) that prevents a substrate (210) from being damaged by a tab (230). To this end, the present invention provides an electrode (200) including: a substrate (210); an active material layer (220) provided on a part of the substrate (210); and a tab (230) in contact with the substrate (210), wherein at least a portion of the tab (230) is located on the active material layer (220).

Inventors

  • KIM, GWI JAE
  • JUNG, WON IL

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260513
Application Date
20251107

Claims (14)

  1. An electrode (200) comprising: a substrate (210); an active material layer (220) provided on a part of the substrate (210); and a tab (230) in contact with the substrate (210), wherein at least a portion of the tab (230) is located on the active material layer (220).
  2. The electrode (200) according to claim 1, wherein the tab (230) is formed such that a first side of the tab (230) is in contact with the substrate (210) and a second side of the tab (230) extends away from the substrate (210), and the tab (230) includes a first edge (231) connecting the first side and the second side.
  3. The electrode (200) of claim 2, wherein at least part of the first edge (231) is located on the active material layer (220).
  4. The electrode (200) according to claim 2 or 3, wherein the tab (230) further includes a second edge (232), the second edge (232) located at a furthest location on the tab (230) from the first edge (231) in a width direction of the tab (230), and wherein at least part of the second edge (232) is located on the active material layer (220).
  5. The electrode (200) according to any of the claims 2 to 4, wherein the tab (230) is located so that at least part of the first edge (231) is in contact with the active material layer (220).
  6. The electrode (200) according to any of the preceding claims, wherein a length of a portion of the tab (230) on the substrate (210) is the same as or less than a length of the substrate (210).
  7. The electrode (200) according to any of the preceding claims, wherein the electrode further comprises: a coated portion (A) on which the active material layer (220) is provided on the substrate (210); and an uncoated portion (N) on which the active material layer (220) is not provided on the substrate (210), wherein the tab (230) is formed to have a wider width than the uncoated portion (N).
  8. The electrode (200) according to any of the preceding claims, wherein the tab (230) is formed with a thickness (t) less than or equal to a thickness (T) of the active material layer (220), and the electrode (200) further comprises a reinforcing layer (240) attached on the tab (230).
  9. The electrode (200) according to any of claims 1 to 7, wherein the tab (230) has a thickness (t) exceeding a thickness (T) of the active material layer (220).
  10. The electrode (200) according to any of the preceding claims, further comprising an insulating tape (250), the insulating tape (250) comprising an insulating material which covers the tab (230).
  11. The electrode (200) according to any of the preceding claims, wherein the tab (230) is electrically connected to the substrate (210), and wherein the tab (230) is in contact with the substrate (210) via a welded portion (j).
  12. The electrode (200) according to claim 11, wherein the welded portion (j) includes a first welded portion (j1, j3) and a second welded portion (j2, j4), which are located spaced apart from each other.
  13. A secondary battery (100) comprising: an electrode assembly (40) formed by winding the electrode (200) according to any preceding claims and a separator (30); and a case (50) accommodating the electrode assembly (40).
  14. The secondary battery according to claim 13, wherein the tab (230) has a thickness of 100 µm or less.

Description

BACKGROUND 1. Field of the Invention The present invention relates to an electrode and a secondary battery capable of preventing cracks from occurring in a substrate. 2. Discussion of Related Art Secondary batteries are batteries that can be charged and discharged, unlike primary batteries that cannot be recharged. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, notebook computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motors in hybrid vehicles, electric vehicles, and the like, and as power storage batteries. These secondary batteries include electrode(s) having a positive electrode and/or a negative electrode, an electrode assembly including the electrode(s), a case accommodating the electrode assembly, an electrode terminal connected to the electrode assembly, and the like. An electrode includes a substrate and an active material layer formed on the substrate. The active material layer includes an active material. In addition, the electrode may include a tab attached on the substrate. An electrode assembly including such electrodes can be, for example, wound to form a jellyroll (i.e., multiple electrodes stacked on top of one another and wound together, resulting in a cylindrical wound structure). When a secondary battery is charged, the electrodes may expand. In such a case, the substrate may be deformed as the electrode is compressed by expansion. In particular, stress applied to the substrate may be concentrated at the tab boundary, which is an area where the tab is attached in the substrate. Accordingly, the tab boundary may reach its local elongation limit, and cracks may occur at the tab boundary. As the demand for high-capacity secondary batteries has increased in recent years, substrates are trending toward becoming thinner. Accordingly, cracks may occur more easily in the substrate. When cracks occur in the electrode, the resistance of the secondary battery increases, heat is generated around the crack, and/or the capacity of the secondary battery decreases, which causes a decrease in the reliability of secondary batteries. The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention and therefore may include information that does not constitute the related art. SUMMARY One embodiment of the present invention relates to an electrode and/or a secondary battery that mitigate(s) cracks from occurring in a substrate. One embodiment of the present invention relates to an electrode and/or a secondary battery that mitigate(s) stress from being concentrated on a substrate by a tab. However, the technical problems to be achieved by the present invention are not limited to the above-mentioned problems, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description. According to the present invention for solving the above technical problem, an electrode includes: a substrate; an active material layer provided on a part of the substrate; and a tab in contact with the substrate, wherein at least a portion of the tab is located on the active material layer. According to the present invention for solving the above technical problem, a secondary battery includes: an electrode assembly formed by winding an electrode and a separator; and a case accommodating the electrode assembly, wherein the electrode includes a substrate, an active material layer provided on a part of the substrate, and a tab in contact with the substrate, wherein at least a portion of the tab is located on the active material layer. BRIEF DESCRIPTION OF THE DRAWINGS The following drawings attached to the present specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described hereinafter, serve to help further understand the technical idea of the present invention, therefore the present invention is not limited to matters described in such drawings, in which: FIG. 1 is a cross-sectional view schematically illustrating an example of a cylindrical secondary battery according to one embodiment of the present invention;FIG. 2 is a cross-sectional view illustrating an example of an electrode;FIG. 3 is a cross-sectional view illustrating an example of an electrode assembly;FIG. 4 is a cross-sectional view illustrating an example of an electrode according to one embodiment of the present invention;FIG. 5 is a cross-sectional view illustrating an example of an electrode according to one embodiment of the present invention;FIG. 6 is a top view illustrating an example of an electrode according to one embodiment of the present invention;FIG. 7 is a cross-sectional view illustrating an example of the thickness of a tab according to one embodiment of the present inven