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CN-122000631-A - Battery cell, battery device and electricity utilization device

CN122000631ACN 122000631 ACN122000631 ACN 122000631ACN-122000631-A

Abstract

The application discloses a battery cell, a battery device and an electricity utilization device, wherein the battery cell comprises a shell and a battery cell, the battery cell is arranged in the shell, the battery cell comprises a pole piece and a diaphragm, a plurality of pole pieces are overlapped along a first direction, the diaphragm is arranged between two adjacent pole pieces, the extending length of the diaphragm along the circumferential direction is larger than that of the pole pieces, and the diaphragm is folded to form a buffer layer at the periphery of the pole pieces. According to the battery monomer, the extending length of the diaphragm along the circumferential direction is larger than that of the pole piece, and the diaphragm is folded on the periphery of the pole piece to form the buffer layer, so that the problem that the conventional diaphragm is poor in protection of the edge of the pole piece can be effectively solved, and powerful guarantee is provided for improving the performance and safety of the battery.

Inventors

  • JIN YIKUANG
  • LOU YONGGANG
  • ZHOU CANG
  • LIU JIAMING
  • GUO YINGCHUN
  • TIAN QINGQING

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (18)

  1. 1. A battery cell, comprising: A housing; -a battery cell (10), the battery cell (10) being mounted in the housing, the battery cell (10) comprising: -a pole piece (11), a plurality of said pole pieces (11) being stacked along a first direction (X); The diaphragm (12) is arranged between two adjacent pole pieces (11), the extension length of the diaphragm (12) along the circumferential direction is larger than that of the pole pieces (11), and the diaphragm (12) is wrinkled on the periphery of the pole pieces (11) to form a buffer layer (120).
  2. 2. The battery cell according to claim 1, wherein an extension of the separator (12) on one side of the second direction (Y) of the pole piece (11) is greater than or equal to an extension of the separator (12) on the other side of the second direction (Y) of the pole piece (11).
  3. 3. The battery cell according to claim 2, wherein the extension length of the separator (12) of one side of the pole piece (11) is L2, and the extension length of the separator (12) of the other side of the pole piece (11) is L1, satisfying: Δl=l2-L1, wherein, delta L of 0mm or less less than or equal to 10mm.
  4. 4. A battery cell according to claim 3, characterized in that the extension length L1 of the separator (12) on the other side of the pole piece (11) is 1mm +.l1 +.20 mm.
  5. 5. The battery cell according to claim 3 or 4, wherein the extension length L2 of the separator (12) at one side of the pole piece (11) satisfies 1mm +.l2 +.20 mm.
  6. 6. The battery cell according to any one of claims 1-5, wherein the cell (10) is a laminated cell (10), The buffer layer (120) is positioned on at least one side of the length direction of the pole piece (11), and/or, The buffer layer (120) is located on at least one side of the pole piece (11) in the width direction.
  7. 7. The battery cell according to any of claims 1-5, wherein the cell (10) is a rolled cell (10), the buffer layer (120) being located at the bottom of the cell (10) or the buffer layer (120) being located at the bottom of the cell (10) and at the top of the cell (10).
  8. 8. The battery cell according to any one of claims 1-5, wherein the separator (12) comprises a plurality of separator segments (121) spaced apart along a first direction (X), adjacent two separator segments (121) of the plurality of separator segments (121) being adapted to overlap each other in a second direction (Y) such that the plurality of separator segments (121) are fixedly connected to each other to construct the buffer layer (120).
  9. 9. The battery cell according to claim 8, wherein a plurality of the separator segments (121) are thermally fused or adhesively bonded.
  10. 10. The battery cell according to claim 8 or 9, wherein the buffer layer (120) of the membrane (12) on one side of the second direction (Y) of the pole piece (11) is a first buffer layer, the buffer layer (120) of the membrane (12) on the other side of the second direction (Y) of the pole piece (11) is a second buffer layer, a plurality of membrane sections (121) of the first buffer layer are fixedly connected, and/or a plurality of membrane sections (121) of the second buffer layer are fixedly connected.
  11. 11. The battery cell according to any one of claims 1 to 10, wherein the electrode sheet (11) includes a positive electrode sheet (111), the positive electrode sheet (111) includes a positive electrode current collector and a positive electrode active material layer provided on at least one side of the positive electrode current collector, the positive electrode current collector including: The conductive layer is arranged on two sides of the polymer matrix, the polymer matrix is provided with a through hole, and the conductive layer is at least partially filled in the through hole.
  12. 12. The battery cell according to claim 11, wherein the positive electrode active material in the positive electrode active material layer includes a compound Li a Ni x Co y Mn z M b O 2 represented by the following formula, wherein 0.60≤a≤ 1.20,0.80≤x≤0.98, y >0, z >0, 0.001≤b≤0.02, and m includes at least one of Al, zr, mg, zn, Y, fe, nb, W, zn, mo, ba, ca, ta and Ti.
  13. 13. The battery cell according to claim 12, further comprising a conductive agent in the positive electrode active material layer, wherein the conductive agent comprises at least one of conductive carbon black, graphene, or carbon nanotubes.
  14. 14. The battery cell according to claim 13, wherein the conductive agent is 0.2% -0.5% by mass.
  15. 15. The battery cell of claim 11, wherein the positive electrode active material layer has a compacted density of 3.45g/cm 3 to 3.8g/cm 3 .
  16. 16. The battery cell of claim 1, wherein the battery cell has an energy density of 750Wh/L to 950Wh/L.
  17. 17. A battery device (100) comprising the battery cell according to any one of claims 1 to 16.
  18. 18. An electrical device, characterized by comprising a battery device (100) according to claim 17, the battery device (100) being adapted to release or store electrical energy.

Description

Battery cell, battery device and electricity utilization device Technical Field The present application relates to the field of electronic battery technology, and in particular, to a battery cell, a battery device, and an electric device. Background In the structure of the battery cell, the separator plays a critical role. The current diaphragm Overhang area does have a good short-circuit prevention effect. The Overhang region is designed to prevent direct contact between the anode and cathode to some extent, thereby reducing the risk of shorting. When the battery is charged and discharged, internal pressure or displacement may occur for various reasons, and the Overhang region can provide an additional barrier to ensure isolation between the electrodes. However, the current diaphragms are not negligible in terms of poor protection of the pole piece edges. The edge of the pole piece is a weaker area and is easily affected by external force, such as collision, extrusion and the like. In actual use, the edges of the pole pieces may be worn, broken, etc., so that the battery performance is reduced and even safety accidents occur. In addition, the active material at the edge of the pole piece may react with the separator, affecting the cycle life and safety of the battery. Disclosure of Invention The present application aims to solve at least one of the technical problems existing in the prior art. Therefore, an object of the present application is to provide a battery cell, which can effectively solve the problem that the existing separator has poor protection to the edge of the polar plate, and provide a powerful guarantee for improving the performance and the safety of the battery. The battery cell comprises a shell and a battery cell, wherein the battery cell is arranged in the shell, the battery cell comprises a pole piece and a diaphragm, a plurality of pole pieces are stacked along a first direction, the diaphragm is arranged between two adjacent pole pieces, the extending length of the diaphragm along the circumferential direction is larger than that of the pole pieces, and the diaphragm is wrinkled to form a buffer layer at the periphery of the pole pieces. In the above example, the extending length of the diaphragm along the circumferential direction is greater than that of the pole piece, and the diaphragm is folded at the periphery of the pole piece to form the buffer layer, so that the problem that the edge of the pole piece is protected poorly by the existing diaphragm can be effectively solved, and powerful guarantee is provided for improving the performance and safety of the battery. In one embodiment of the application, the extension of the diaphragm on one side of the second direction of the pole piece is greater than or equal to the extension of the diaphragm on the other side of the second direction of the pole piece. In the above example, the longer side of the diaphragm extension may provide more robust protection in a particular direction (e.g., the bottom of the pole piece in fig. 3), reducing the likelihood of problems between the pole piece and the diaphragm due to external factors or internal stresses. In the above example, this symmetrical design allows the pole pieces to be protected more evenly in all directions. In one embodiment of the application, the extending length of the diaphragm on one side of the pole piece is L2, the extending length of the diaphragm on the other side of the pole piece is L1, and delta L=L2-L1 is satisfied, wherein delta L is more than or equal to 0mm and less than or equal to 10mm. In the above example, a reasonable Δl range ensures that the diaphragm has sufficient extension on both sides of the pole piece, providing good protection for the pole piece. In one embodiment of the application, the extending length L1 of the diaphragm at the other side of the pole piece is 1 mm-L1-20 mm. In the above examples, a reasonable length range ensures that the diaphragm has sufficient extension on both sides of the pole piece, providing effective protection for the pole piece. In one embodiment of the application, the extension length L2 of the diaphragm at one side of the pole piece is 1mm < L2 < 20mm. In the above examples, a reasonable length range ensures that the diaphragm has sufficient extension on both sides of the pole piece, providing effective protection for the pole piece. In one embodiment of the application, the membrane on one side of the pole piece has an extension equal to the extension of the membrane on the other side of the pole piece. In the above example, this symmetrical design allows the pole pieces to be protected more evenly in all directions. In one embodiment of the present application, the battery cell is a laminated battery cell, the buffer layer is located on at least one side in the length direction of the pole piece, and/or the buffer layer is located on at least one side in the width direction of the pole piece. In the above exampl