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EP-4369430-B1 - ELECTRODE ASSEMBLY, AND SECONDARY BATTERY, BATTERY PACK, AND VEHICLE COMPRISING ELECTRODE ASSEMBLY

EP4369430B1EP 4369430 B1EP4369430 B1EP 4369430B1EP-4369430-B1

Inventors

  • YUN, SU HYUN
  • AN, HYO SUN
  • JUNG, BUM YOUNG

Dates

Publication Date
20260506
Application Date
20230622

Claims (15)

  1. An electrode assembly (100), which is made by winding a positive electrode (20), a separator (40), and a negative electrode (10), wherein the negative electrode (10) comprises: a negative electrode active material portion (11); and a negative electrode non-coated portion (12), wherein the negative electrode active material portion (11) made by applying a negative electrode active material onto a negative electrode current collector; and wherein the negative electrode non-coated portion (12) including a central negative electrode non-coated portion (12a) positioned at a winding center portion and having no negative electrode active material and an outermost peripheral negative electrode non-coated portion (12b) positioned at an outermost winding periphery, wherein a variable unit (30) is provided on the outermost peripheral negative electrode non-coated portion (12) and configured to adjust a length or width thereof, and wherein the variable unit (30) comprises: one or more cutout portions (31) having a non-straight shape; and a variable portion (32) configured to adjust a length or width thereof.
  2. The electrode assembly (100) of claim 1, wherein the cutout portion (31) is provided in the form of a cut line or a cut groove.
  3. The electrode assembly (100) of claim 2, wherein the cut line includes a broken line or a cut line.
  4. The electrode assembly (100) of claim 1, wherein the non-straight shape has a zigzag shape or a wavy shape.
  5. The electrode assembly (100) of claim 1, wherein the cutout portion (31) is provided in any one of or both length and width directions of the negative electrode non-coated portion (12).
  6. The electrode assembly (100) of claim 1, wherein the negative electrode non-coated portions (12) are positioned at front and rear ends based on a length direction of the variable unit (30), and the electrode assembly (100) further includes one or more fixed portions (33) fixed to a boundary line between the variable unit (30) and the negative electrode non-coated portion (12).
  7. The electrode assembly (100) of claim 1, wherein the variable portion (32) includes the same material as the negative electrode current collector.
  8. The electrode assembly (100) of claim 1, wherein the outermost peripheral negative electrode non-coated portion (12) includes a negative electrode non-coated portion (12b') and a second negative electrode non-coated portion (12b"), and the variable unit is positioned between the first negative electrode non-coated portion (12b') and the second negative electrode non-coated portion (12b").
  9. The electrode assembly (100) of claim 1, wherein one surface or two opposite surfaces of the variable portion (32) are coated with an electrically conductive material.
  10. The electrode assembly (100) of claim 1, wherein the cutout portion (31) is provided as one or two or more cutout portions (31).
  11. The electrode assembly (100) of claim 10, wherein the two or more cutout portions (31) are provided, and at least two cutout portions (31) are provided in the same direction.
  12. The electrode assembly (100) of claim 10, wherein the two or more cutout portions (31) are provided, and all the cutout portions (31)e provided in different directions.
  13. A secondary battery (1) comprising: the electrode assembly (100) according to any one of claims 1 to 12; a casing (200) having one open side with an opening portion and configured to accommodate the electrode assembly (100); and a cap assembly (300) coupled to the open opening portion of the casing (200).
  14. A battery pack (3) comprising the secondary battery (1)according to claim 13.
  15. A transport means (V) comprising the battery pack (3) according to claim 14.

Description

[Technical Field] The present invention relates to an electrode assembly and a secondary battery, battery pack, and transport means including the same. [Background Art] Unlike primary batteries, secondary batteries may be rechargeable and have small scales and high capacities. Recently, research and development have been actively conducted on the secondary batteries. As development of technologies and demands for mobile devices are increased, there is a rapidly increasing demand for rechargeable batteries as energy sources. The secondary batteries are classified into coin batteries, cylindrical batteries, angular batteries, and pouch-type batteries depending on shapes of battery casings. In the secondary battery, an electrode assembly mounted in the battery casing is a power generation element that has a structure made by coating electrodes and separators and may be charged and discharged. The electrode assemblies may be approximately classified into a Jelly-roll-type electrode assembly made by winding sheet-shaped positive and negative electrodes coated with active materials with a separator interposed therebetween, a stack-type electrode assembly made by sequentially coating a plurality of positive and negative electrodes in a state in which separators are interposed between the plurality of positive and negative electrodes, and a stack-and-folding-type electrode assembly made by winding stack-type unit cells by using long separation films. In the related art, because an active material expands at the time of charging or discharging the secondary battery having the jelly-roll-type electrode assembly, tension is applied to an electrode non-coated portion, which causes a problem in which the electrode non-coated portion cracks. US2018/062146 A1 disclose a stacked electrode assembly including a pair of first electrode and second electrode, each including a first current collector sheet and a first active material layer and a second current collector sheet and second active material layers attached to both surfaces of the second current collector sheet, respectively. A first tab and second tab are cut out from the same conductive sheet material as that of first current collector sheet and second current collector sheet respectively to obtain a seamless-structured integrated product. The tab is an exposed part of the conductive sheet material of the same as the current collector sheet. The tab is provided with a plurality of slits in a direction intersecting the extending direction of the tab and forms a planar first spring structure that expands and contracts in the extending direction. EP 3 392 924 A1 disclose an electrode assembly shaped as an electrodes stack and including an anode containing an anode composite material and an anode current collector. Anode tabs protrude from the anode current collector and comprise rated brake points which can be unfolded without being torn apart. [Detailed Description of the Invention] [Technical Problem] The present invention has been made in an effort to solve the above-mentioned problem in the related art, and an object of the present invention is to provide an electrode assembly in which contraction and expansion of a negative electrode non-coated portion, which is positioned at an outermost periphery of the electrode assembly, may accommodate a change in volume when an active material expands in volume, and a secondary battery, battery pack, and transport means including the same. [Technical Solution] The present invention provides an electrode assembly, which is made by winding a positive electrode, a separator, and a negative electrode, wherein the negative electrode comprises: a negative electrode active material portion; and a negative electrode non-coated portion, wherein the negative electrode active material portion made by applying a negative electrode active material onto a negative electrode current collector; and wherein the negative electrode non-coated portion including a central negative electrode non-coated portion positioned at a winding center portion and having no negative electrode active material and an outermost peripheral negative electrode non-coated portion positioned at an outermost winding periphery, wherein a variable unit is provided on the outermost peripheral negative electrode non-coated portion and configured to adjust a length or width thereof, and wherein the variable unit comprises: one or more cutout portions having a non-straight shape; and a variable portion configured to adjust a length or width thereof. Tthe present invention provides a secondary battery including the electrode assembly; a casing having one open side and configured to accommodate the electrode assembly; and a cap assembly coupled to the open opening portion of the casing. The present invention provides a battery pack including the secondary battery. The present invention provides a transport means including the battery pack. Further embodiments are disclosed i