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EP-4742426-A1 - SECONDARY BATTERY AND METHOD FOR MANUFACTURING THE SAME

EP4742426A1EP 4742426 A1EP4742426 A1EP 4742426A1EP-4742426-A1

Abstract

A secondary battery includes an electrode assembly comprising a plurality of electrode plates and a plurality of separators between the plurality of electrode plates, the plurality of electrode plates comprising first tabs and second tabs, and each of the plurality of electrode plates comprises a coating part coated with an active material, a current collector electrically connected to the first tabs and the second tabs, and a case accommodating the electrode assembly, wherein the current collector includes a first section to which the first tabs are connected, and the first section includes a first sub-section to which a portion of the first tabs is welded in an initially bent state and a second sub-section to which a remaining portion of the first tabs is welded in a secondarily bent state.

Inventors

  • KIM, MINWOO
  • HWANG, INHYUN
  • SONG, Daseong

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260513
Application Date
20250929

Claims (15)

  1. A secondary battery (1000), comprising: an electrode assembly (200) comprising a plurality of electrode plates and a plurality of separators between the plurality of electrode plates, the plurality of electrode plates comprising first tabs (11) and second tabs (12), and each of the plurality of electrode plates comprises a coating part (20) coated with an active material; a current collector (100) electrically connected to the first tabs (11) and the second tabs (12); and a case (1100) accommodating the electrode assembly (200), wherein: the current collector (100) comprises a first section (110) to which the first tabs (11) are connected, and the first section (110) comprises a first sub-section (111) to which a portion of the first tabs (11) is welded in an initially bent state and a second sub-section (113) to which a remaining portion of the first tabs (11) is welded in a secondarily bent state.
  2. The secondary battery (1000) according to claim 1, wherein: the current collector (100) further comprises a second section (120) to which the second tabs (12) are welded, and the second section (120) comprises a third sub-section (121) to which a portion of the second tabs (12) is welded in an initially bent state and a fourth sub-section (123) to which a remaining portion of the second tabs (12) is welded in a secondarily bent state.
  3. The secondary battery (1000) according to claim 2, wherein the first tabs (11) and the second tabs (12) are each welded to the first sub-section (111) and the third sub-section (121), respectively, and wherein the first tabs (11) and the second tabs (12) are initially bent in opposite directions.
  4. The secondary battery (1000) according to claims 2 or 3, wherein the first tabs (11) and the second tabs (12) are each welded to the second sub-section (113) and the fourth sub-section (123), respectively, and wherein the first tabs (11) and the second tabs (12) are secondarily bent in a same direction.
  5. The secondary battery (1000) according to any of claims 2 to 4, wherein: the current collector (100) further comprises a central section (130), the first sub-section (111) extends in a first direction from the central section (130), the third sub-section (121) extends in a second direction from the central section (130), and the second direction is different from the first direction.
  6. The secondary battery (1000) according to any of claims 2 to 5, wherein: the portion of the first tabs (11) and the first sub-section (111) are welded to each other on a first plane and the portion of the second tabs (12) and the third sub-section (121) are welded on the first plane, the remaining portion of the first tabs (11) and the third sub-section (121) are welded on a second plane different from the first plane, and the remaining portion of the second tabs (12) and the fourth sub-section (123) are welded on a third plane different from the first plane and parallel to the second plane.
  7. The secondary battery (1000) according to any of claims 1 to 6, wherein a separation space is between the remaining portion of the first tabs (11) welded to the second sub-section (113) and an outermost coating part adjacent to the second sub-section (113).
  8. The secondary battery (1000) according to any of claims 1 to 7, wherein: a first set of welding lines (101) is on the first sub-section (111), and each of the first set of welding lines (101) extends in a direction in which the first tabs (11) are initially bent.
  9. The secondary battery (1000) according to any of claims 1 to 8, wherein: a second set of welding lines (103) is on the second sub-section (113), and each of the second set of welding lines (103) extends in a direction in which the first tabs (11) are secondarily bent.
  10. A method for manufacturing a secondary battery (1000), the method comprising: preparing an electrode assembly (200) comprising a plurality of electrode plates and a plurality of separators disposed between the plurality of electrode plates, wherein first tabs (11) and second tabs (12) are formed in the plurality of electrode plates, and each of the plurality of electrode plates comprises a coating part (20) coated with an active material; preparing a current collector (100) comprising a first section (110) electrically connected to the first tabs (11) and a second section (120) electrically connected to the second tabs (12); initially bending the first tabs (11); secondarily bending the first tabs (11); welding a portion of the first tabs (11) to a first sub-section (111) of the first section (110), wherein the first tabs (11) are initially bent; welding a remaining portion of the first tabs (11) to a second sub-section (113) of the first section (110), wherein the first tabs (11) are secondarily bent; and inserting the electrode assembly (200) coupled with the current collector (100) into a case (1100).
  11. The method for manufacturing a secondary battery (1000) according to claim 10, further comprising: initially bending the second tabs (12); secondarily bending the second tabs (12); welding a portion of the second tabs (12) to a third sub-section (121) of the second section (120) wherein the second tabs (12) are initially bent; and welding a remaining portion of the second tabs (12) to a fourth sub-section (123) of the second section (120), wherein the second tabs (12) are secondarily bent.
  12. The method for manufacturing a secondary battery (1000) according to claim 11, wherein the first tabs (11) and the second tabs (12) are each welded to the first sub-section (111) and the third sub-section (121), respectively, and wherein the first tabs (11) and the second tabs (12) are initially bent in opposite directions.
  13. The method for manufacturing a secondary battery (1000) according to claim 11 or 12, wherein the first tabs (11) and the second tabs (12) are each welded to the second sub-section (113) and the fourth sub-section (123), respectively, and wherein the first tabs (11) and the second tabs (12) are secondarily bent in a same direction.
  14. The method for manufacturing a secondary battery (1000) according to any of claims 11 to 13, wherein: welding between the portion of the first tabs (11) and the first sub-section (111) and welding between the portion of the second tabs (12) and the third sub-section (121) are performed on a first plane, welding between the remaining portion of the first tabs (11) and the third sub-section (121) is performed on a second plane different from the first plane, and welding between the remaining portion of the second tabs (12) and the fourth sub-section (123) is performed on a third plane different from the first plane and parallel to the second plane.
  15. The method for manufacturing a secondary battery (1000) according to any of claims 10 to 14, the method further comprising: before secondarily bending the first tabs (11), arranging a support plate (50) on one surface of the electrode assembly (200); wherein welding to the second sub-section (113) comprises welding the remaining portion of the first tabs (11) to the second sub-section (113) of the first section (110), wherein the support plate is arranged between the remaining portion of the first tabs (11) and an outermost coating part adjacent to the second sub-section (113); and after welding to the second sub-section (113), removing the support plate (50).

Description

BACKGROUND 1. Field The present invention relates to a secondary battery and a method for manufacturing the same. 2. 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. The above information disclosed in this Background section is for enhancement of understanding of the background of the present invention, and therefore, it may contain information that does not constitute related (or prior) art. SUMMARY OF THE INVENTION The present invention concerns a secondary battery, including an electrode assembly including a plurality of electrode plates and a plurality of separators between the plurality of electrode plates, wherein the plurality of electrode plates comprise first tabs and second tabs, in particular being formed in the plurality of electrode plates, and each of the plurality of electrode plates includes a coating part coated with an active material, a current collector electrically connected to the first tabs and the second tabs, and a case accommodating the electrode assembly, wherein the current collector includes a first section to which the first tabs are connected, and the first section includes a first sub-section to which a portion of the first tabs is welded in an initially bent state and a second sub-section to which a remaining portion of the first tabs is welded in a secondarily bent state. The current collector may further include a second section to which the second tabs are welded, and the second section may include a third sub-section to which a portion of the second tabs is welded in an initially bent state and a fourth sub-section to which a remaining portion of the second tabs is welded in a secondarily bent state. The first tabs and the second tabs may each be welded to the first sub-section and the third sub-section, respectively, and wherein the first tabs and the second tabs may be initially bent in opposite directions. The first tabs and the second tabs may each be welded to the second sub-section and the fourth sub-section, respectively, and wherein the first tabs and the second tabs may be secondarily bent in a same direction. The current collector may further include a central section, the first sub-section may extend in a first direction from the central section, the third sub-section may extend in a second direction from the central section, and the second direction may be different from the first direction. Welding between the portion of the first tabs and the first sub-section and welding between the portion of the second tabs and the third sub-section may be performed on a first plane, welding between the remaining portion of the first tabs and the third sub-section may be performed on a second plane different from the first plane, and welding between the remaining portion of the second tabs and the fourth sub-section may be performed on a third plane different from the first plane and parallel to the second plane. A separation space may be between the remaining portion of the first tabs welded to the second sub-section and an outermost coating part adjacent to the second sub-section. A first set of welding lines may be on the first sub-section, and each of the first set of welding lines may extend in a direction in which the first tabs are initially bent. A second set of welding lines may be on the second sub-section, and each of the second set of welding lines may extend in a direction in which the first tabs are secondarily bent. The first tabs may be laser welded to the first section. The case may include a first long-side wall and a second long-side wall facing each other and being spaced apart from each other, and a first short-side wall and a second short-side wall facing each other and being spaced apart from each other, wherein the first short-side wall and the second short-side wall may have a smaller area than the first long-side wall and the second long-side wall, the first sub-section may face the first short-side wall, and the second sub-section may face the first long-side wall. Further the present invention concerns a method for manufacturing a secondary battery, the method including preparing an electrode assembly including a plurality of electrode plates and a plurality of separators disposed between the plurality of electrode pla