Search

CN-121986403-A - Battery monomer, battery and electric equipment

CN121986403ACN 121986403 ACN121986403 ACN 121986403ACN-121986403-A

Abstract

The battery unit (10), the battery (100) and the electric equipment, the battery unit (10) comprises a shell (11), an end cover (12) and an electrode assembly (2), the shell (11) is provided with an opening along at least one end of a first direction (Z), the shell (11) comprises a first wall (111), the end cover (12) is used for sealing the opening, the first wall (111) and the end cover (12) are welded to form a first connecting part (51), the electrode assembly (2) is at least partially contained in the shell (11), the electrode assembly (2) comprises an anode pole piece (22) and a cathode pole piece (23), at least part of the anode pole piece (22) and at least part of the cathode pole piece (23) are arranged in a stacked mode along a second direction (Y), the second direction (Y) is parallel to the thickness direction of the first wall (111), the first direction (Z) is intersected with the second direction (Y), the first wall (111) comprises a main body part (400), the main body part (400) is located on one side of the first connecting part (51) facing away from the end cover (12), and the main body part (400) is provided with a buffer structure (410) and a buffer structure (410) is arranged at a distance from the first connecting part (51).

Inventors

  • CAO MENGKAI
  • ZHOU WENLIN
  • WU YU
  • ZHENG YULIAN
  • LI CAN
  • WANG PENG

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260505
Application Date
20240819

Claims (20)

  1. A battery cell, wherein the battery cell comprises: A housing having an opening along at least one end of a first direction, the housing including a first wall; An end cover closing the opening, the first wall and the end cover being welded to form a first connection; An electrode assembly at least partially accommodated in the case, the electrode assembly including a positive electrode tab and a negative electrode tab, at least part of the positive electrode tab and at least part of the negative electrode tab being stacked along a second direction, the second direction being parallel to a thickness direction of the first wall, the first direction intersecting the second direction; The first wall comprises a main body part, the main body part is located at one side, away from the end cover, of the first connecting part along the first direction, a buffer structure is arranged on the main body part, and the buffer structure is arranged at intervals with the first connecting part.
  2. The battery cell according to claim 1, wherein the buffer structure includes a weak portion provided on the main body portion, and a minimum thickness of the weak portion is smaller than a thickness of other portions of the main body portion.
  3. The battery cell according to claim 2, wherein the inner surface of the main body portion is provided with a groove and/or the outer surface of the main body portion is provided with a groove, and the weak portion is an area of the main body portion opposite to a notch of the groove.
  4. The battery cell according to claim 3, wherein the groove includes a first side surface, a second side surface, and a bottom surface connected to the first side surface and the second side surface, the weak portion includes a first weak portion disposed opposite to the bottom surface, and a thickness of the first weak portion is smaller than a thickness of other portions of the main body portion.
  5. The battery cell according to claim 4, wherein the weak portion further comprises a second weak portion disposed opposite the first side and a third weak portion disposed opposite the second side, the first side being located on a side of the bottom surface adjacent to the first connection portion, and the thickness of the second weak portion being in an increasing trend in a direction adjacent to the first connection portion, the second side being located on a side of the bottom surface facing away from the first connection portion, and the thickness of the third weak portion being in an increasing trend in a direction facing away from the first connection portion.
  6. The battery cell of claim 4 or 5, wherein the first side and the bottom face have an included angle greater than or equal to 135 degrees and less than 180 degrees, and/or the second side and the bottom face have an included angle greater than or equal to 135 degrees and less than 180 degrees.
  7. The battery cell according to any one of claims 1-6, wherein the buffer structure comprises a first protrusion and a first recess, the first protrusion being disposed in correspondence with the first recess, the first protrusion protruding from an outer surface of the body portion, the first recess being recessed outwardly from an inner surface of the body portion.
  8. The battery cell according to claim 7, wherein the number of the first protrusions is plural, the number of the first recesses is plural, and each first protrusion is provided with one of the first recesses.
  9. The battery cell according to any one of claims 1 to 8, wherein the buffer structure includes a second convex portion and a second concave portion, the second convex portion being provided in correspondence with the second concave portion, the second convex portion protruding from an inner surface of the main body portion, the second concave portion being recessed inward from an outer surface of the main body portion.
  10. The battery cell according to claim 9, wherein the number of the second protrusions is plural, the number of the second recesses is plural, and each second protrusion is provided with one of the second recesses.
  11. The battery cell according to any one of claims 1-10, wherein the buffer structure is spaced from the edge of the first connection portion by H in the first direction, H satisfying 0.3mm +.7 mm, optionally 1.5mm +.4 mm.
  12. The battery cell according to any one of claims 1-11, wherein the electrode assembly further comprises a separator, the separator being disposed between the positive electrode tab and the negative electrode tab; The positive electrode plate comprises a positive electrode main body area and a positive electrode tab protruding from the positive electrode main body area, the positive electrode main body area is provided with a positive electrode active material layer, the negative electrode plate comprises a negative electrode main body area and a negative electrode tab protruding from the negative electrode main body area, the negative electrode main body area is provided with a negative electrode active material layer, the positive electrode main body area is provided with a first end facing the end cover along the first direction, the negative electrode main body area is provided with a second end facing the end cover, the separator is provided with a third end facing the end cover, and the third end is closer to the end cover than the first end and the second end.
  13. The battery cell of claim 12, wherein the separator includes an excess region that extends beyond the first and second ends in a first direction, an orthographic projection of the excess region overlapping an orthographic projection of the buffer structure in a projection plane perpendicular to the second direction.
  14. The battery cell of claim 12 or 13, wherein the orthographic projection of the positive body region does not overlap with the orthographic projection of the buffer structure in a projection plane perpendicular to the second direction, and/or wherein the orthographic projection of the negative body region does not overlap with the orthographic projection of the buffer structure in a projection plane perpendicular to the second direction.
  15. The battery cell of any one of claims 1-14, wherein the negative electrode tab comprises a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector, the negative electrode active material layer comprising a negative electrode active material.
  16. The battery cell according to claim 15, wherein the anode active material layer includes an anode main body portion and an anode thinned portion, the anode main body portion and the anode thinned portion being arranged in the first direction, along which the anode main body portion is provided with the anode thinned portion near an end of the end cap.
  17. The battery cell of claim 16, wherein an orthographic projection of the negative electrode thinning portion and an orthographic projection of the buffer structure are disposed at intervals along the first direction in a projection plane perpendicular to the second direction.
  18. The battery cell of claim 17, wherein a dimension of a separation of an orthographic projection of the negative electrode thinned portion from an orthographic projection of the buffer structure along the first direction in a projection plane perpendicular to the second direction is greater than or equal to 1mm.
  19. The battery cell of any of claims 15-18, wherein the negative electrode active material layer has a single-sided coating weight of 90mg/1540mm 2 ～170mg/1540mm 2 , optionally 110mg/1540mm 2 ～150mg/1540mm 2 .
  20. The battery cell of any one of claims 15-19, wherein the negative electrode sheet has a porosity of 27% -40%.

Description

Battery monomer, battery and electric equipment Technical Field The application relates to the technical field of batteries, in particular to 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. In battery technology, the service life of the battery cells is a non-negligible problem. Therefore, how to improve the service life of the battery cell is a technical problem to be solved in the battery technology. Disclosure of Invention In view of the above problems, the application provides a battery cell, a battery and electric equipment, which can effectively prolong the service life of the battery cell. In a first aspect, an embodiment of the application provides a battery cell, which comprises a shell, an end cover and an electrode assembly, wherein at least one end of the shell along a first direction is provided with an opening, the shell comprises a first wall, the end cover seals the opening, the first wall and the end cover are welded to form a first connecting part, the electrode assembly is at least partially accommodated in the shell and comprises a positive electrode plate and a negative electrode plate, at least part of the positive electrode plate and at least part of the negative electrode plate are stacked along a second direction, the second direction is parallel to the thickness direction of the first wall, and the first direction is intersected with the second direction; Wherein, first wall includes the main part, along first direction, and the main part is located one side that first connecting portion deviates from the end cover, and the main part is equipped with buffer structure, buffer structure and first connecting portion interval setting. In the above technical solution, the buffer structure can absorb the expansion force generated during the use of the electrode assembly, thereby reducing the expansion force directly acting on the first connection part. Therefore, the buffer structure can reduce the risk of fatigue cracking of the region of the first wall, which is located near the first connection portion, due to expansion of the electrode assembly, thereby improving the service life of the battery cell. In some embodiments, the cushioning structure includes a frangible portion disposed on the body portion, the frangible portion having a minimum thickness that is less than a thickness of the remainder of the body portion. In this way, the weak portion can absorb the expansion force more effectively than the other portions of the main body portion, thereby reducing the expansion force directly acting on the first connecting portion. Therefore, the weak portion can reduce the risk of fatigue cracking of the region of the first wall located near the first connection portion due to expansion of the electrode assembly, thereby improving the service life of the battery cell. In some embodiments, the inner surface of the body portion is provided with a groove and/or the outer surface of the body portion is provided with a groove, and the frangible portion is an area of the body portion opposite the mouth of the groove. Therefore, the weak part is used as a region opposite to the groove opening, has better buffering performance, is easier to form, reduces the manufacturing difficulty of the shell, and further reduces the manufacturing cost of the shell. In some embodiments, the groove includes a first side, a second side, and a bottom surface connected to the first side and the second side, and the weakened portion includes a first weakened portion disposed opposite the bottom surface, the first weakened portion having a thickness less than a thickness of the other portion of the body portion. In this way, the first weak portion can absorb the expansion force more effectively than the other portions of the main body portion, thereby reducing the expansion force directly acting on the first connecting portion. Therefore, the first weak portion can reduce the risk of fatigue cracking of the region of the first wall located near the first connection portion due to expansion of the electrode assembly, thereby improving the service life of the battery cell. In some embodiments, the weak portion further includes a second weak portion disposed opposite to the first side and a third weak portion disposed opposite to the second side, the first side is located on a side of the bottom surface near the first connecting portion, and a thickness of the second weak portion is in an increasing trend along a direction near the first connecting portion, the second side is located on a s