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CN-121986397-A - Battery monomer, battery and electric equipment

CN121986397ACN 121986397 ACN121986397 ACN 121986397ACN-121986397-A

Abstract

The application provides a battery unit (20), a battery (100) and electric equipment, wherein the battery unit (20) comprises an electrode assembly (23) and a buffer piece (24), the electrode assembly (23) comprises a first pole piece (231), a second pole piece (232) and a separator (233), the first pole piece (231), the second pole piece (232) and the separator (233) are wound along a winding direction (X) to form a winding body (23 b), the center of the winding body (23 b) forms a central hole (23 b 1) along a winding axial direction (Y), the buffer piece (24) is at least partially arranged in the central hole (23 b 1), and the buffer piece (24) is connected with the first pole piece (231) and/or the second pole piece (232), and in the embodiment of the application, the buffer piece (24) can support the first pole piece (231) and the second pole piece (232) in the central hole (23 b 1) of the winding body (23 b), so that the most loose problem of the first pole piece (231) and the second pole piece (232) in the winding body (23 b) can be effectively solved.

Inventors

  • LIU HUANJI
  • CAI RUNCHEN
  • SUN XIN

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260505
Application Date
20240719

Claims (20)

  1. A battery cell is characterized by comprising An electrode assembly including a first electrode sheet, a second electrode sheet, and a separator between the first electrode sheet and the second electrode sheet, wherein the first electrode sheet, the second electrode sheet, and the separator are wound in a winding direction to form a wound body, a center hole is formed in a center of the wound body in a winding axis direction, the winding direction is perpendicular to the winding axis direction, and The buffer piece is at least partially arranged in the central hole and is connected with the first pole piece and/or the second pole piece.
  2. The battery cell of claim 1, wherein the first electrode sheet is sequentially formed with an empty foil region and a coating region along the winding direction, the coating region is used for coating an active material layer, at least part of the empty foil region exceeds the second electrode sheet in a direction opposite to the winding direction, and the buffer member is connected to the empty foil region.
  3. The battery cell of claim 2, wherein the hollow foil region is wound in the winding direction to form at least one hollow foil fold, and the buffer is connected to the hollow foil fold.
  4. The battery cell of claim 3, wherein the hollow foil sections are wound in the winding direction and alternately form at least one hollow foil straight portion and at least one hollow foil bent portion, and wherein the buffer member is connected to the hollow foil straight portion and the hollow foil bent portion.
  5. The battery cell of claim 2, wherein the hollow foil region is formed with at least one hollow foil flat portion along the winding direction, and the buffer is connected to the hollow foil flat portion.
  6. The battery cell of any one of claims 2 to 5, wherein the buffer member includes a first buffer portion disposed inside the empty foil region.
  7. The battery cell of claim 6, wherein the buffer comprises a second buffer portion disposed outside the empty foil region.
  8. The battery cell of claim 7, wherein the first buffer is disposed opposite the second buffer.
  9. The battery cell according to claim 2 to 8, wherein the length o of the buffer member in the winding direction is smaller than or equal to the length p of the empty foil region.
  10. The battery cell of claim 2, wherein the end of the buffer forms a gap with the beginning of the coating zone in the winding direction.
  11. The battery cell of any one of claims 1 to 10, wherein the first electrode sheet is a cathode electrode sheet and the second electrode sheet is an anode electrode sheet.
  12. The battery cell of any one of claims 1 to 10, wherein the first electrode sheet is an anode electrode sheet and the second electrode sheet is a cathode electrode sheet.
  13. The battery cell of claim 1, wherein the first pole piece comprises a single-sided coating region and a double-sided coating region sequentially arranged along the winding direction, the buffer member is arranged on the inner side of the single-sided coating region, and at least part of the single-sided coating region exceeds the second pole piece in a direction opposite to the winding direction.
  14. The battery cell according to any one of claims 1 to 13, wherein the width of the buffer member in the winding axial direction is smaller than or equal to the width of the wound body, and the buffer member does not protrude out of the center hole.
  15. The battery cell of claim 14, wherein the wound body has a width a and the buffer has a width b in the axial direction of the winding, wherein 0≤a-b≤2 mm.
  16. The battery cell of claim 15, wherein 0≤a-b≤1 mm.
  17. The battery cell of any one of claims 1 to 16, wherein the buffer has a compression ratio c of 30% to 90%.
  18. The battery cell of claim 17, wherein 50% c≤70%.
  19. The battery cell of any one of claims 1 to 18, wherein the buffer has a thickness d of 0.5 mm≤d≤4 mm.
  20. The battery cell of claim 19, wherein d is 0.5 mm≤d≤2 mm.

Description

Battery monomer, battery and electric equipment Technical Field The application relates to the technical field of battery monomers, and particularly provides a battery monomer, a battery and electric equipment. Background Energy conservation and emission reduction are key to sustainable development of the automobile industry, and electric vehicles become an important component of sustainable development of the automobile industry due to the energy conservation and environmental protection advantages of the electric vehicles. For electric vehicles, battery technology is an important factor in the development of the electric vehicles. The battery cell typically includes a housing, an electrode assembly, and an electrolyte, both of which are sealed within the housing. In the design of an electrode assembly, a winding form is a common form, and a winding body is formed by disposing a cathode electrode sheet, an anode electrode sheet and a separator at intervals and winding around a winding needle. However, after the winding is completed and the winding core is drawn out of the winding body, the cathode pole piece and the anode pole piece of the inner ring of the winding body are loose due to no support in the winding body, so that the distance between the cathode pole piece and the anode pole piece is increased, and the problem of lithium precipitation is caused. Content of the application The embodiment of the application aims to provide a battery monomer, a battery and electric equipment, and aims to solve the problem that lithium is separated due to the fact that a pole piece in a winding body is easy to loose. In order to achieve the above purpose, the technical scheme adopted by the embodiment of the application is as follows: In a first aspect, an embodiment of the application provides a battery cell, which comprises an electrode assembly and a buffer piece, wherein the electrode assembly comprises a first pole piece, a second pole piece and a separator positioned between the first pole piece and the second pole piece, the first pole piece, the second pole piece and the separator are wound along a winding direction to form a winding body, the center of the winding body forms a center hole along a winding axial direction, the winding direction is perpendicular to the winding axial direction, the buffer piece is at least partially arranged in the center hole, and the buffer piece is connected with the first pole piece and/or the second pole piece. The battery monomer has the beneficial effects that at least part of the buffer piece is arranged in the central hole of the winding body and is connected with the first pole piece and/or the second pole piece, so that the buffer piece can support the first pole piece and the second pole piece in the central hole of the winding body, the expansion force generated by expansion in the charge and discharge process of the battery monomer is balanced, the problem that the first pole piece and the second pole piece are loose in the central hole of the winding body can be effectively solved, and the probability of lithium precipitation is reduced. In some embodiments, the first pole piece is sequentially formed with an empty foil region and a coating region along the winding direction, the coating region is used for coating the active substance layer, at least part of the empty foil region exceeds the second pole piece in the direction opposite to the winding direction, and the buffer piece is connected to the empty foil region. Through adopting foretell technical scheme, empty foil area and coating district form on first pole piece along the winding direction in proper order, and at least partial empty foil area surpasss the second pole piece in the direction of being in the winding direction dorsad, from this, after connecting the bolster on empty foil area, when coiling the formation winding body along the winding direction with first pole piece, second pole piece and separator, at least part in empty foil area can be located the centre bore to at least part in bolster also will be located the centre bore, and then the bolster can realize the supporting role to coating district and the second pole piece of first pole piece. In some embodiments, the blank foil area is wound in a winding direction to form at least one blank foil bending portion, and the cushioning member is connected to the blank foil bending portion. Through adopting foretell technical scheme, the bolster can be on empty foil kink and support the coating district and the second pole piece of first pole piece to increase the corner clearance of coating district and the second pole piece of first pole piece in kink, thereby realize reducing the probability that the coating district and the second pole piece of first pole piece take place brittle failure. In some embodiments, the blank foil sections are wound in a winding direction and alternately form at least one blank foil flat portion and at least one