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EP-4489106-B1 - NEGATIVE ELECTRODE SHEET, BATTERY CELL, BATTERY PACK, AND ELECTRICITY-CONSUMPTION DEVICE

EP4489106B1EP 4489106 B1EP4489106 B1EP 4489106B1EP-4489106-B1

Inventors

  • YUAN, Jielin
  • YU, TONG

Dates

Publication Date
20260506
Application Date
20240510

Claims (10)

  1. A negative electrode sheet (100), comprising: a negative-electrode current collector (110); and a negative-electrode material layer (120), wherein the negative-electrode material layer (120) is disposed on a surface of the negative-electrode current collector (110) and comprises a first active material, wherein the first active material comprises a first particle cluster and a second particle cluster, wherein a compaction density of the first particle cluster after being compressed at a pressure of 5 tons is P1, and wherein a compaction density of the second particle cluster after being compressed at the pressure of 5 tons is P2, wherein P1 and P2 satisfy 1.0 ≤ P1/P2 ≤ 1.5, wherein: when a volume percentage in the first particle cluster reaches 50%, a corresponding particle size value Dv50 satisfies 13 µm ≤ Dv50 ≤ 20 µm; when a volume percentage in the second particle cluster reaches 50%, a corresponding particle size value Dv50' satisfies 5 µm ≤ Dv50' ≤ 12 µm; and a specific surface area of the first particle cluster before being compressed is S1, a specific surface area of the first particle cluster after being compressed is S2, a specific surface area of the second particle cluster before being compressed is S1', and a specific surface area of the second particle cluster after being compressed is S2', wherein S1, S2, S1', and S2' satisfy 1.0 ≤ (S2/S1)/(S2'/S1') ≤ 3.0, wherein S1, S2, S1' and S2' are measured according to the description.
  2. The negative electrode sheet of claim 1, wherein the compaction density P1 of the first particle cluster after being compressed at the pressure of 5 tons satisfies 1.6 g/cm 3 ≤ P1 ≤ 2.0 g/cm 3 .
  3. The negative electrode sheet of any one of claims 1 to 2, wherein the compaction density P2 of the second particle cluster after being compressed at the pressure of 5 tons satisfies 1.25 g/cm 3 ≤ P2 ≤ 1.7 g/cm 3 .
  4. The negative electrode sheet of any one of claims 1 to 3, wherein the first particle cluster satisfies 0.5 ≤ (Dv90-Dv10)/Dv50 ≤ 1.3, wherein Dv90 represents a corresponding particle size value when the volume percentage in the first particle cluster reaches 90%, Dv10 represents a corresponding particle size value when the volume percentage in the first particle cluster reaches 10%
  5. The negative electrode sheet of any one of claims 1 to 4, wherein the second particle cluster satisfies 0.8 ≤ (Dv90'-Dv10')/Dv50' ≤ 1.6, wherein Dv90' represents a corresponding particle size value when the volume percentage in the second particle cluster reaches 90%, Dv10' represents a corresponding particle size value when the volume percentage in the second particle cluster reaches 10%.
  6. The negative electrode sheet of any one of claims 1 to 5, wherein S1 and S2 satisfy 1.0 ≤ S2/S1 ≤ 5.4.
  7. The negative electrode sheet of any one of claims 1 to 6, wherein S1' and S2' satisfy: 1.0 ≤ S2'/S1' ≤ 1.8.
  8. A battery cell (200), comprising: an electrolyte (210); a positive electrode sheet (100) at least partially immersed in the electrolyte (210); a separator (230) located at one side of the positive electrode sheet (100) and at least partially immersed in the electrolyte (210); and the negative electrode sheet (100) of any one of claims 1 to 7, wherein the negative electrode sheet (100) is disposed at one side of the separator (230) away from the positive electrode sheet (100) and at least partially immersed in the electrolyte (210).
  9. A battery pack (300), comprising: a box (310); and a plurality of battery cells (200) of claim 8, the plurality of battery cells (200) being received in the box (310) and electrically connected in series and/or in parallel.
  10. An electricity-consumption device (400), comprising: a device body (410); and the battery cell (200) of claim 8, wherein the battery cell (200) is configured to power the device body (410).

Description

TECHNICAL FIELD This disclosure relates to the technical field of battery cells, and in particular, to a negative electrode sheet, a battery cell, a battery pack, and an electricity-consumption device. BACKGROUND At present, energy crisis and environmental pollution are increasingly serious, and secondary battery cells, as a new type of energy conversion devices, are increasingly widely used. However, in the related art, an improvement of an energy density of a secondary battery cell usually results in a reduction in a dynamics performance of the secondary battery cell or a relatively short cycle life of the secondary battery cell. EP 4 145 564 A1 discloses a secondary battery comprising an electrode assembly that has a body part and a tab extending from the body part. The body part comprises a negative electrode sheet comprising a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector. The negative electrode film layer comprises a first region and second region disposed at two sides of the first region in a tab extension direction. The first region comprises a first negative electrode active material, and the first negative electrode active material comprises artificial graphite. The second region comprises a second negative electrode active material, and the second negative electrode active material comprises graphite. The DC impedance of the portion of the negative electrode sheet corresponding to the first region is marked as R1, and the DC impedance of the portion of the negative electrode sheet corresponding to the second region is marked as R2, and the second battery satisfies that: R1 < R2. SUMMARY Aspects of the invention are set out in the appended claim. The present disclosure provides a negative electrode sheet, a battery cell, a battery pack, and an electricity-consumption device are provided in the disclosure, where the battery cell may have a relatively high energy density and a relatively good cycling performance in the case where the negative electrode sheet is applied in the battery cell. In the negative electrode sheet provided in the disclosure, the negative-electrode material layer includes the first active material, the first active material includes the first particle cluster and the second particle cluster, and the corresponding particle size value when the volume percentage in the first particle cluster reaches 50% is greater than the corresponding particle size value when the volume percentage in the second particle cluster reaches 50%, and thus at the same pressure, the compaction density of the first particle cluster is greater than the compaction density of the second particle cluster, i.e., a particle size is positively correlated with a compaction density. In the disclosure, the compaction density of the first particle cluster at the pressure of 5 tons is P1, the compaction density of the second particle cluster at the pressure of 5 tons is P2, and P1 and P2 satisfy: 1.0 ≤ P1/P2 ≤ 1.5. In the embodiments of the disclosure, the compaction density of the first particle cluster and the compaction density of the second particle cluster are both in a reasonable range, and thus a degree of graphitization of the first particle cluster and a degree of graphitization of the second particle cluster can be both in a reasonable range during manufacturing of the negative electrode sheet, so that in the case where the negative electrode sheet is applied in a battery cell, the battery cell may have a relatively high energy density and a relatively good cycling performance. In the case where P1/P2>1.5, on the one hand, it may be that the compaction density P1 of the first particle cluster is too high. In this case, particle sizes of particles in the first particle cluster are too large, so that a degree of graphitization of the particles in the first particle cluster is relatively high during manufacturing of the negative electrode sheet, which results in a reduction in lattice defects of the negative electrode sheet. Therefore, in the case where the negative electrode sheet is applied in the battery cell, when active ions move to be embedded into the negative electrode sheet or dis-embedded from the negative electrode sheet, the active ions need to move a relatively long distance to be embedded into the negative electrode sheet or dis-embedded from the negative electrode sheet, resulting in polarization of the battery cell during cycling of the battery cell. Polarization of the battery cell causes consumption of excessive active ions, and thus the cycling performance of the battery cell is reduced in the case where the negative electrode sheet is applied in the battery cell. On the other hand, in the case where P1/P2>1.5, it may be that the compaction density P2 of the second particle cluster is too low. In this case, particle sizes of particles in the second particle cluster are too small, so that