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US-20260128474-A1 - SECONDARY BATTERY

US20260128474A1US 20260128474 A1US20260128474 A1US 20260128474A1US-20260128474-A1

Abstract

A secondary battery includes an electrode assembly including a first electrode plate having a first electrode uncoated portion, a second electrode plate having a second electrode uncoated portion, and a separator between the first electrode plate and the second electrode plate, an insulating layer covering the first electrode uncoated portion, a thickness of the insulating layer on the first electrode uncoated portion at an outer side of the electrode assembly being greater than a thickness of the insulating layer on the first electrode uncoated portion at an inner side of the electrode assembly; and a case accommodating the electrode assembly with the insulating layer.

Inventors

  • Min Gyu Jung
  • Jung Hyun Lee
  • Jeong Yi PARK
  • Hye Min Park
  • Gi Wook LEE

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260507
Application Date
20250522
Priority Date
20241105

Claims (20)

  1. 1 . A secondary battery, comprising: an electrode assembly including a first electrode plate having a first electrode uncoated portion, a second electrode plate having a second electrode uncoated portion, and a separator between the first electrode plate and the second electrode plate; an insulating layer covering the first electrode uncoated portion, a thickness of the insulating layer on the first electrode uncoated portion at an outer side of the electrode assembly being greater than a thickness of the insulating layer on the first electrode uncoated portion at an inner side of the electrode assembly; and a case accommodating the electrode assembly with the insulating layer.
  2. 2 . The secondary battery as claimed in claim 1 , wherein the first electrode plate includes: a first electrode current collector plate which is a metal foil; a first electrode active material on at least one surface of the first electrode current collector plate; and the first electrode uncoated portion at one end in a first direction of the first electrode current collector plate, the first electrode active material not being on the first electrode uncoated portion.
  3. 3 . The secondary battery as claimed in claim 2 , wherein the insulating layer includes a first end covering a sidewall of the first electrode active material.
  4. 4 . The secondary battery as claimed in claim 3 , wherein the insulating layer includes a region overlapping the first electrode active material in the first direction.
  5. 5 . The secondary battery as claimed in claim 3 , wherein the insulating layer includes a second end opposite the first end in the first direction, the second end being on the first electrode uncoated portion and having a thickness that is equal to or smaller than a thickness of the first electrode active material.
  6. 6 . The secondary battery as claimed in claim 3 , wherein the insulating layer includes a second end opposite the first end in the first direction, the second end being on the first electrode uncoated portion and having a thickness that is 40% to 70% of a thickness of the first electrode active material.
  7. 7 . The secondary battery as claimed in claim 2 , wherein the first electrode active material is on each of opposite sides of the first electrode current collector, the insulating layer being on each of opposite sides of the first electrode uncoated portion.
  8. 8 . The secondary battery as claimed in claim 1 , wherein: the electrode assembly is a stack type in which the first electrode plate, the separator, the second negative electrode plate, and an additional separator are sequentially and repeatedly stacked multiple times; and a thickness of an outermost insulating layer on the first electrode plate at an outermost side of the electrode assembly is greater than a thickness of an inner insulating layer on the first electrode plate at the inner side of the electrode assembly.
  9. 9 . The secondary battery as claimed in claim 8 , wherein the thickness of the inner insulating layer is 50% to 90% of the thickness of the outermost insulating layer.
  10. 10 . The secondary battery as claimed in claim 8 , wherein a thickness of the insulating layer on the first electrode plate at a center of the electrode assembly is smaller than a thickness of the insulating layer on another first electrode plate.
  11. 11 . The secondary battery as claimed in claim 8 , wherein: the electrode assembly includes a plurality of the first electrode plate, and each of the plurality of the first electrode plate further includes a first electrode tab extending in a first direction from the first electrode uncoated portion, the insulating layer partially covering a surface of the first electrode tab.
  12. 12 . The secondary battery as claimed in claim 11 , wherein the insulating layer has a smaller length in the first direction than a length of the first electrode tab in the first direction.
  13. 13 . The secondary battery as claimed in claim 11 , wherein the first electrode tab is aligned and stacked with an adjacent first electrode tab in a same position.
  14. 14 . The secondary battery as claimed in claim 1 , wherein the electrode assembly is of a jelly-roll type in which the first electrode plate, the separator, the second negative electrode plate, and an additional separator are sequentially stacked in a plate or film shape.
  15. 15 . The secondary battery as claimed in claim 14 , wherein the insulating layer gradually increases in thickness from a winding leading edge to a winding trailing edge.
  16. 16 . The secondary battery as claimed in claim 14 , wherein a thickness of the insulating layer covering an outer surface of the first electrode uncoated portion is greater than a thickness of the insulating layer covering an inner surface of the first electrode uncoated portion.
  17. 17 . The secondary battery as claimed in claim 14 , wherein: the insulating layer at a winding trailing edge region, which is an outermost side of the electrode assembly, has a larger thickness than the insulating layer at an inner region, which is the inner side of the electrode assembly, and the winding trailing edge region corresponds to a length in which the first electrode plate at the outermost side of the electrode assembly is wound at least once.
  18. 18 . The secondary battery as claimed in claim 17 , wherein the insulating layer in the inner region has a uniform thickness.
  19. 19 . The secondary battery as claimed in claim 1 , wherein the first electrode plate is a positive electrode plate, and the second electrode plate is a negative electrode plate.
  20. 20 . The secondary battery as claimed in claim 1 , wherein the insulating layer includes a ceramic.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0154902, filed on Nov. 5, 2024, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. BACKGROUND 1. Field The present disclosure relates to a secondary battery. 2. Description of the Related Art A secondary battery is a power storage system that converts electric energy into chemical energy and stores the converted energy to provide high energy density. Unlike primary batteries that cannot be recharged, a secondary battery is rechargeable and is being widely used in IT devices, such as a smart phone, a cellular phone, a notebook computer, or a tablet PC. In recent years, electric vehicles are drawing attention for protection of environmental contamination, and a trend toward the use of high-capacity secondary batteries for electric vehicles is growing. The secondary battery needs to have high density, high output and stability characteristics. The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure, and therefore, it may contain information that does not constitute related (or prior) art. SUMMARY A secondary battery according to one embodiment of the present disclosure includes an electrode assembly including a first electrode plate having a first electrode uncoated portion, a second electrode plate having a second electrode uncoated portion, and a separator disposed between the first electrode plate and the second electrode plate, and including an insulating layer provided to cover the first electrode uncoated portion; and a case accommodating the electrode assembly, wherein in the electrode assembly, the thickness of the insulating layer provided on the first electrode plate located at the outermost side may be greater than the thickness of the insulating layer provided on the first electrode plate located at the inner side of the electrode assembly. The first electrode plate may include a first electrode current collector plate which is a metal foil; a first electrode active material provided on at least one surface of the first electrode current collector plate; and a first electrode uncoated portion at one end in a first direction of the first electrode current collector plate, to which the first electrode active material is not applied. The insulating layer may have the one end in first direction cover the sidewall of the first electrode active material. The insulating layer may have a region overlapping the first electrode active material in the first direction. The first electrode active material may be provided on each of both sides of the first electrode current collector, and the insulating layer may be provided on each of both sides of the first electrode uncoated portion. The thickness of the insulating layer may be equal to or smaller than the thickness of the first electrode active material. The thickness of the insulating layer may be 40% to 70% of the thickness of the first electrode active material. The electrode assembly may be of a stack type in which the first electrode plate, the separator, the second negative electrode plate, and the separator are sequentially and repeatedly stacked in multiple times, and the thickness of the outermost insulating layer provided on the first electrode plate located at the outermost side may be greater than the thickness of the inner insulating layer provided on the first electrode plate located at the inner side The thickness of the inner insulating layer may be 50% to 90% of the thickness of the outermost insulating layer. The thickness of the insulating layer provided on the first electrode plate located at the center of the electrode assembly may be smaller than the thickness of the insulating layer provided on another first electrode plate. The plurality of first electrode plates may each further include a first electrode tab extending in the first direction from the first electrode uncoated portion, and the insulating layer may be provided to partially cover the surface of the multiple first electrode tab. The insulating layer may have a smaller length in the first direction than the length of the first electrode tab in the first direction. Multiple first electrode tabs are aligned and stacked at the same position. The electrode assembly may be of a jelly-roll type in which the first electrode plate, the separator, the second negative electrode plate, and the separator are sequentially stacked in a plate or film shape. The insulating layer may gradually increase in thickness from the winding leading edge to the winding trailing edge. The thickness of the insulating layer provided to cover the outer surface of the first electrode uncoated portion may be greater than the thickness of the insulating layer provided to cover the inner surface of the first electrode uncoated portion. T