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EP-4742343-A1 - ELECTRODE ASSEMBLY AND SECONDARY BATTERY INCLUDING ELECTRODE ASSEMBLY

EP4742343A1EP 4742343 A1EP4742343 A1EP 4742343A1EP-4742343-A1

Abstract

An electrode assembly according to the present disclosure includes a first electrode connected to a first electrode tab, a second electrode connected to a second electrode tab, and a separator that is positioned between the first electrode and the second electrode. The first electrode, the separator and the second electrode are sequentially stacked and wound around a winding axis such that the electrode assembly includes a core portion having a center hole formed therein and an outer portion connected to the core portion. A length of the core portion in a direction of the winding axis is different from a length of the outer portion in the direction of the winding axis.

Inventors

  • CHO, SUNGMIN

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260513
Application Date
20251007

Claims (15)

  1. A secondary battery (100) comprising: an electrode assembly (200, 500); a cylindrical case (120) accommodating the electrode assembly (200, 500); a cap plate (130) sealing an opening of the cylindrical case (120); and a gasket (140) positioned between the cap plate (130) and the cylindrical case (120), wherein the electrode assembly (200, 500) comprises: a first electrode (210, 510) connected to a first electrode tab (212, 512), a second electrode (220, 520) connected to a second electrode tab (222, 522), and a separator (230, 530) that is interposed between the first electrode (210, 510) and the second electrode (220, 520), wherein the first electrode (210, 510), the separator (230, 530), and the second electrode (220, 520) are sequentially stacked and wound around a winding axis (Y) to form the electrode assembly (200, 500), with the electrode assembly (200, 500) including a core portion (260, 560) having a center hole (250, 550) formed therein and an outer portion (270, 570) connected to the core portion (260, 560), and wherein a length of the core portion (260, 560) in a direction of the winding axis (Y) is longer than a length of the outer portion (270, 570) in the direction of the winding axis (Y).
  2. The secondary battery (100) according to claim 1, wherein the cap plate (130) comprises: a first flat portion (132) positioned at a center and protruding in a direction away from the electrode assembly (200, 500) accommodated in the case (120), a second flat portion (136) located outside the first flat portion (132), and a connection portion (134) positioned between the first flat portion (132) and the second flat portion (136).
  3. The secondary battery (100) according to claim 2, wherein the connection portion (134) is inclined radially outward from the first flat portion (132).
  4. The secondary battery (100) according to claim 2 or 3, wherein a notch (139) is formed in a lower surface of the second flat portion (136) of the cap plate (130).
  5. The secondary battery (100) according to any one of claims 2 to 4, wherein the outer portion (270, 570) comprises: a first outer portion (270_1, 570_1) connected to the core portion (260, 560), and a second outer portion (270_2, 570_2) connected to the first outer portion (270_1, 570_1), wherein a length of the first outer portion (270_1, 570_1) in the direction of the winding axis (Y) is shorter than the length of the core portion (260, 560) in the direction of the winding axis (Y), and wherein a length of the second outer portion (270_2, 570_2) in the direction of the winding axis (Y) is shorter than the length of the first outer portion (270_1, 570_1) in the direction of the winding axis (Y).
  6. The secondary battery (100) according to claim 5, wherein the first electrode tab (212, 512) and the second electrode tab (222, 522) protrude from the first outer portion (270_1, 570_1).
  7. The secondary battery (100) according to any one of claims 2 to 6, wherein the first electrode tab (212, 512) is connected to the second flat portion (136) of the cap plate (130).
  8. The secondary battery (100) according to any one of claims 1 to 7, wherein the second electrode tab (222, 522) is connected to a bottom portion (122) of the case (120).
  9. The secondary battery (100) according to any one of claims 1 to 8, further comprising an insulating member (150, 850) interposed between the cap plate (130) and the electrode assembly (200, 500).
  10. The secondary battery (100) according to claim 5 or 6, wherein the electrode assembly (200, 500) comprises: a first outer surface (262, 562) formed by the core portion (260, 560), a second outer surface (272_1, 572_1) formed by the first outer portion (270_1, 570_1), and a third outer surface (272_2, 572_2) formed by the second outer portion (270_2, 570_2).
  11. The secondary battery (100) according to claim 10, wherein a top of the core portion (260, 560), a top of the first outer portion (270_1, 570_1), and a top of the second outer portion (270_2, 570_2) extend along lines or planes that are parallel to each other, wherein the first outer surface (262) is perpendicular to the top of the core portion (260) and the top of the first outer portion (270_1), and wherein the second outer surface (272_1) is perpendicular to the top of the first outer portion (270_1) and the top of the second outer portion (270_2).
  12. The secondary battery (100) according to claim 10, wherein a top of the core portion (560), a top of the first outer portion (570_1), and a top of the second outer portion (570_2) extend along lines or planes that are parallel to each other, wherein the first outer surface (562) and the second outer surface (572_1) are inclined radially outward from the core portion (560) and the first outer portion (570_1), respectively.
  13. The secondary battery (100) according to any one of claims 2 to 12, wherein a top of the core portion (260, 560) is higher than a bottom of the second flat portion (136) of the cap plate (130) in the direction of the winding axis (Y).
  14. The secondary battery (100) according to any one of claims 5 to 13, wherein a top of the first outer portion (270_1, 570_1) is higher than a bottom of the gasket (140) in the direction of the winding axis (Y).
  15. The secondary battery (100) according to any one of claims 5 to 14, wherein a longest diameter (D3) of the first outer portion (270_1, 570_1) is shorter than a diameter (D4) of a circle formed by an inner surface of the gasket (140).

Description

BACKGROUND FIELD This disclosure relates to an electrode assembly and a secondary battery including the electrode assembly. Description of the Related Art Unlike primary batteries that are not designed to be (re)charged, secondary (or rechargeable) batteries are batteries that are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable, small electronic devices, such as smart phones, feature phones, notebook computers, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles and electric vehicles and for storing power (e.g., home and/or utility scale power storage). A secondary battery generally includes an electrode assembly composed of a positive electrode and a negative electrode, a case accommodating the same, and electrode terminals connected to the electrode assembly. In secondary batteries, energy density is the amount of energy that may be stored per unit volume. High energy density secondary batteries provide increased operating time in portable devices and increased driving range in electric vehicles. Accordingly, the energy density of secondary batteries is recognized as one of the important factors determining the performance of secondary batteries, and various efforts have been made to improve the energy density of secondary batteries. 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 Various aspects of the present disclosure relate to an electrode assembly and a secondary battery including the electrode assembly. These and other aspects and features of the present disclosure will be described in or will be apparent from the following description of embodiments of the present disclosure. According to various aspects of the disclosure, there is provided an electrode assembly including: a first electrode connected to a first electrode tab; a second electrode connected to a second electrode tab; and a separator that is positioned between the first electrode and the second electrode, in which the first electrode, the separator, and the second electrode are sequentially stacked and wound around a winding axis such that the electrode assembly includes a core portion having a center hole formed therein and an outer portion connected to the core portion, and a length of the core portion in a direction of the winding axis is different from a length of the outer portion in the direction of the winding axis. According to various aspects, the outer portion may include a first outer portion connected to the core portion, and a second outer portion connected to the first outer portion, a length of the first outer portion in the direction of the winding axis may be shorter than the length of the core portion in the direction of the winding axis, and a length of the second outer portion in the winding axis direction may be longer than the length of the first outer portion in the direction of the winding axis. According to various aspects, the first electrode tab and the second electrode tab may protrude from the first outer portion. According to various aspects, the electrode assembly may include a first outer surface formed by the core portion, a second outer surface formed by the first outer portion, and a third outer surface formed by the second outer portion. According to various aspects, a top of the core portion, a top of the first outer portion, and a top of the second outer portion may extend along lines or planes that are parallel to each other, the first outer surface may be perpendicular to the top of the core portion and the top of the first outer portion, and the second outer surface may be perpendicular to the top of the first outer portion and the top of the second outer portion. According to various aspects, a top of the core portion, a top of the first outer portion, and a top of the second outer portion may extend along lines or planes that are parallel to each other, and the first outer surface and the second outer surface may be inclined radially outward from the core portion and the first outer portion, respectively. According to various aspects of the disclosure, there is provided a secondary battery including: an electrode assembly; a cylindrical case accommodating the electrode assembly; a cap plate sealing an opening of the cylindrical case; and a gasket interposed between the cap plate and the cylindrical case, in which the electrode assembly includes a first electrode connected to a first electrode tab; a second electrode connected to a second electrode tab; and a separator that is interposed between the first electrode and the second electrode, wherein the first electrode, the separator and the second electrode are sequentially stacked and wound around a winding axis to fo