Search

EP-4738552-A1 - BATTERY CELL, BATTERY APPARATUS AND ELECTRICAL APPARATUS

EP4738552A1EP 4738552 A1EP4738552 A1EP 4738552A1EP-4738552-A1

Abstract

A battery cell, a battery apparatus, and an electrical apparatus. The battery cell includes a housing (11), an electrode assembly (2) and an end cover (12), where at least one end of the housing (11) in a first direction is provided with an opening, and the housing (11) comprises a first side wall part (111). The electrode assembly (2) is at least partially accommodated in the housing (11). The electrode assembly (2) includes a positive pole piece (22) and a negative pole piece (23). At least part of the positive pole piece (22) and at least part of the negative pole piece (23) are stacked in a second direction. The second direction is parallel to the thickness direction of the first side wall part (111). The first direction intersects with the second direction. The end cover (12) is used for sealing the opening, and the first side wall part (111) and the end cover (12) are welded to form a first connecting part (51). The first side wall part (111) comprises, arranged in a first direction, a first area (1111) and a second area (1112). The first area (1111) is located between the first connecting part (51) and the second area (1112). The hardness of the first area (1111) is less than the hardness of the second area (1112). The expansion force of the electrode assembly (2) is released by means of the first area (1111) having a lower hardness, so as to reduce the possibility of cracking of the first connecting part (51) of the first side wall part (111).

Inventors

  • CAO, Mengkai
  • ZHOU, WENLIN
  • JIANG, Xiangwei
  • HUANG, Shoujun
  • ZHENG, YULIAN
  • WANG, PENG

Assignees

  • Contemporary Amperex Technology Co., Limited

Dates

Publication Date
20260506
Application Date
20240830

Claims (20)

  1. A battery cell, comprising: a housing having an opening in at least one end thereof in a first direction and comprising a first side wall part; an electrode assembly at least partially accommodated in the housing, wherein the electrode assembly comprises a positive pole piece and a negative pole piece, at least part of the positive pole piece and at least part of the negative pole piece are stacked in a second direction, the second direction is parallel to the thickness direction of the first side wall part, and the first direction intersects with the second direction; an end cover used for sealing the opening, wherein the first side wall part and the end cover are welded to form a first connecting part; wherein the first side wall part comprises, arranged in a first direction, a first area and a second area, the first area is located between the first connecting part and the second area, and the hardness of the first area is less than the hardness of the second area.
  2. The battery cell according to claim 1, wherein a ratio of the hardness of the first area to the hardness of the second area is between 0.3 and 0.8.
  3. The battery cell according to claim 2, wherein a ratio of the hardness of the first area to the hardness of the second area is between 0.5 and 0.8.
  4. The battery cell according to any one of claims 1 to 3, wherein the hardness of the second area ranges from 40 HV to 100 HV, and the hardness of the first area ranges from 20 HV to 55 HV.
  5. The battery cell according to any one of claims 1 to 4, wherein a dimension of the first area in the first direction ranges from 0.05 mm to 0.75 mm.
  6. The battery cell according to claim 5, wherein a dimension of the first area in the first direction ranges from 0.1 mm to 0.6 mm.
  7. The battery cell according to any one of claims 1 to 6, wherein at least some of the grains in the first area are first grains, a ratio of a number of the first grains in the first area to the number of all the grains in the first area is more than 50%, and a dimension of the first grains that extends in the first direction is a first dimension, a maximum dimension of the first grains in the second direction is a second dimension, and a ratio of the first dimension to the second dimension ranges from 0.2 to 5.
  8. The battery cell according to claim 7, wherein a ratio of the first dimension to the second dimension ranges from 0.25 to 4.
  9. The battery cell according to claim 7 or 8, wherein the first dimension ranges from 5 to 500 µm, and the second dimension ranges from 5 to 500 µm.
  10. The battery cell according to any one of claims 1 to 9, wherein at least some of the grains in the second area are second grains, a ratio of a number of the second grains in the second area to a number of all the grains in the second area is more than 50%, and a dimension of the second grains that extends in the first direction is a third dimension, a maximum dimension of the second grains in the second direction is a fourth dimension, and a ratio of the third dimension to the fourth dimension ranges from 4 to 100.
  11. The battery cell according to claim 10, wherein a ratio of the third dimension to the fourth dimension ranges from 4 to 50.
  12. The battery cell according to claim 10 or 11, wherein the third dimension ranges from 150 to 1000 µm, and the fourth dimension ranges from 5 to 120 µm.
  13. The battery cell according to any one of claims 1 to 12, wherein at least some of the grains in the first area are first grains, a ratio of a number of the first grains in the first area to the number of all the grains in the first area is more than 50%, and a dimension of the first grains that extends in the first direction is a first dimension, a maximum dimension of the first grains in the second direction is a second dimension, and a ratio of the first dimension to the second dimension ranges from 0.2 to 5; at least some of the grains in the second area are second grains, a ratio of a number of the second grains in the second area to a number of all the grains in the second area is more than 50%, and a dimension of the second grains that extends in the first direction is a third dimension, a maximum dimension of the second grains in the second direction is a fourth dimension, and a ratio of the third dimension to the fourth dimension ranges from 4 to 100; wherein the third dimension is greater than the first dimension.
  14. The battery cell according to claim 13, wherein a ratio of the third dimension to the first dimension ranges from 1.5 to 150, or the ratio of the third dimension to the first dimension ranges from 1.8 to 100.
  15. The battery cell according to claim 13 or 14, wherein the first dimension ranges from 5 to 500 µm, and the third dimension ranges from 150 to 1000 µm.
  16. The battery cell according to any one of claims 1 to 15, wherein a maximum thickness of the first area is greater than a minimum thickness of the second area.
  17. The battery cell according to claim 16, wherein the first side wall part has a first inner surface and a second inner surface facing the electrode assembly and a first outer surface and a second outer surface facing away from the electrode assembly, the first inner surface and the second inner surface being successively connected in a direction from the end cover toward the electrode assembly, the first outer surface and the second outer surface are successively connected in a direction from the end cover toward the electrode assembly, the first inner surface and the second inner surface are at least partially formed in the first area, the second inner surface and the second outer surface are at least partially formed in the second area, a distance between the first inner surface and the first outer surface in the second direction is larger than a distance between the second inner surface and the second outer surface in the second direction.
  18. The battery cell according to claim 17, wherein the first inner surface comprises a first sub-face and a second sub-face successively connected in the direction from the end cover toward the electrode assembly, the first sub-face being formed at least partially in the first area, the first sub-face being more adjacent to the electrode assembly than the second sub-face in the second direction, a distance between the first sub-face and the first outer surface in the second direction being larger than a distance between the second sub-face and the first outer surface in the second direction.
  19. The battery cell according to claim 18, wherein a distance between the second sub-face and the first outer surface in the second direction is a first preset thickness, and the first preset thickness exhibits a decreasing trend in the direction from the end cover toward the electrode assembly.
  20. The battery cell according to claim 18 or 19, wherein the first sub-face spans across the first area and the second area, and the first outer surface spans across the first area and the second area; or, the second sub-face spans across the first area and the second area, and the first outer surface spans across the first area and the second area.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims the priority of Chinese patent application with the application No. 202410217408.8 and the filing date of February 27, 2024, International Patent Application with the application No. PCT/CN 2024/113179 and the filing date of August 19, 2024, International Patent Application with the application No. PCT/CN 2024/105243 and the filing date of July 12, 2024, and International Patent Application with the application No. PCT/CN 2024/089160 and the filing date of April 22, 2024, International Patent Application No. PCT/CN 2023/135607 and the filing date of November 30, 2023, International Patent Application No. PCT/CN 2023/134129 and the filing date of November 24, 2023, which are incorporated herein by reference in their entirety. TECHNICAL FIELD The present application relates to the field of battery technology, and in particular, to a battery cell, a battery apparatus, and an electrical apparatus. BACKGROUND Batteries are becoming more and more widely used in life and industry. Batteries are used not only in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also in electric tools such as electric bicycles, electric motorcycles, and electric vehicles. In the related art, an electrode assembly is provided in a housing of a battery cell, and during charging and discharging of the battery cell, the electrode assembly may expand, possibly resulting in cracking of the housing. SUMMARY In view of the above, it is desirable in the embodiments of the present application to provide a battery cell, a battery apparatus, and an electrical apparatus, which are capable of reducing the possibility of cracking of a housing. In order to achieve the above-mentioned objective, the technical solutions of the embodiments of the present application are achieved as follows: disclosed in an aspect of embodiments of the present application is a battery cell including:a housing having an opening in at least one end thereof in a first direction and including a first side wall part;an electrode assembly at least partially accommodated in the housing, where the electrode assembly includes a positive pole piece and a negative pole piece, at least part of the positive pole piece and at least part of the negative pole piece are stacked in a second direction, the second direction is parallel to the thickness direction of the first side wall part, and the first direction intersects with the second direction;an end cover used for sealing the opening, where the first side wall part and the end cover are welded to form a first connecting part;where the first side wall part includes, arranged in a first direction, a first area and a second area, the first area is located between the first connecting part and the second area, and hardness of the first area is greater than hardness of the second area. The expansion force of the electrode assembly is released by means of the first area having a lower hardness, so as to reduce the possibility of cracking of the first connecting part. In some embodiments, a ratio of the hardness of the first area to the hardness of the second area is between 0.3 and 0.8. An appropriate hardness can both reduce the cracking of the first connecting part and restrain the cracking of the first area itself. In some embodiments, a ratio of the hardness of the first area to the hardness of the second area is between 0.5 and 0.8. An appropriate hardness can both reduce the cracking of the first connecting part and restrain the cracking of the first area itself. In some embodiments, the hardness of the second area ranges from 40 HV to 100 HV, and the hardness of the first area ranges from 20 HV to 55 HV. An appropriate hardness can both reduce the cracking of the first connecting part and restrain the cracking of the first area itself. In some embodiments, a dimension of the first area in the first direction ranges from 0.05 mm to 0.75 mm. An appropriate dimension range of the maximum dimension of the first area in the first direction can both reduce the cracking of the first connecting part and restrain the first area from being excessively long and cracking itself. In some embodiments, a dimension of the first area in the first direction ranges from 0.1mm to 0.6mm. An appropriate dimension range of the maximum dimension of the first area in the first direction can both reduce the cracking of the first connecting part and restrain the first area from being excessively long and cracking itself. In some embodiments, at least some of the grains in the first area are first grains, a ratio of a number of the first grains in the first area to a number of all grains in the first area is greater than 50%, and a dimension of the first grains that extends in the first direction is a first dimension, a maximum dimension of the first grains in the second direction is a second dimension, and a ratio of the first dimens