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CN-122000417-A - Battery cell, battery device and electricity utilization device

CN122000417ACN 122000417 ACN122000417 ACN 122000417ACN-122000417-A

Abstract

The application relates to the technical field of batteries, in particular to a battery cell, a battery device and an electric device, wherein the battery cell comprises a negative electrode plate, the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, the negative electrode film layer comprises a negative electrode active material, the negative electrode active material comprises an inner core layer and an outer shell layer, the inner core layer comprises graphite, and the outer shell layer comprises metal silicide. The battery monomer has smaller charge transfer impedance and can improve the charging capability.

Inventors

  • Bian Cancan
  • CHEN HUI
  • SONG YING
  • Guo Suogang
  • FU CHENGHUA
  • YE YONGHUANG
  • MA WENJIAN
  • LIN YUNMEI

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (12)

  1. 1. The battery cell is characterized by comprising a negative electrode plate; The negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector; The negative electrode film layer comprises a negative electrode active material; The negative electrode active material includes a core layer and an outer shell layer; the inner core layer comprises graphite, and the outer shell layer comprises metal silicide.
  2. 2. The battery cell of claim 1, wherein at least a portion of the graphite of the outer surface of the inner core layer and at least a portion of the metal silicide of the inner surface of the outer shell layer form a metal silicon carbon compound.
  3. 3. The battery cell according to claim 1 or 2, wherein the negative electrode active material has a Dv50 particle size of 1-30 μm, optionally 5-15 μm.
  4. 4. A battery cell according to any of claims 1-3, wherein the metal element in the metal silicide comprises one or more of copper, iron, tantalum, tungsten, hafnium, niobium, vanadium, chromium, magnesium, zirconium, molybdenum, zinc, calcium or titanium.
  5. 5. The battery cell according to any of claims 1-4, wherein the metal silicide has a Dv50 particle size of 5-200nm, optionally 5-20nm.
  6. 6. The battery cell of any one of claims 1-5, wherein the outer shell layer has a mass of 0.1% -30% based on 100% of the total mass of the inner core layer, and/or; the thickness of the outer shell layer is 1-10nm, alternatively 3-7nm.
  7. 7. The battery cell of any one of claims 1-6, wherein the negative electrode film layer has a compacted density of 1.6-1.8g/cm 3 at 0% charge.
  8. 8. A method for preparing a negative electrode active material, comprising the steps of: arranging an outer shell layer on the surface of the inner core layer to obtain the anode active material; the raw materials of the inner core layer comprise graphite, and the raw materials of the outer shell layer comprise metal silicide.
  9. 9. The method of claim 8, wherein the disposing comprises disposing the outer shell layer on a surface of at least a portion of the inner core layer and then heat treating the outer shell layer.
  10. 10. The method according to claim 9, wherein the heat treatment is carried out at a temperature of 700-1200 ℃, and/or; the heat treatment time is 1-10h.
  11. 11. A battery device, characterized in that it comprises a plurality of battery cells according to any one of claims 1-7.
  12. 12. An electric device, characterized in that the electric device comprises the battery cell according to any one of claims 1 to 7, or the negative electrode active material obtained by the production method according to any one of claims 8 to 10, or the battery device according to claim 11.

Description

Battery cell, battery device and electricity utilization device Technical Field The application relates to the technical field of batteries, in particular to a battery cell, a battery device and an electricity utilization device. Background The battery monomer has wide application due to the excellent performance, and in the prior art, as the graphite is used as the battery monomer of the negative electrode active material, the charge transfer resistance of the formed battery monomer is larger due to fewer active sites on the surface of the graphite, so that the charging capability of the battery monomer is limited. Disclosure of Invention In view of the above, the present application provides a battery cell, a battery device, and an electric device, in which the battery cell has a small charge transfer resistance and a good charging capability. In a first aspect, the present application provides a battery cell comprising a negative electrode tab; The negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector; The negative electrode film layer comprises a negative electrode active material; The negative electrode active material includes a core layer and an outer shell layer; the inner core layer comprises graphite, and the outer shell layer comprises metal silicide. In the technical scheme of the embodiment of the application, the metal element nucleation site in the metal silicide is low, has good affinity to active ions, improves the active site on the graphite surface in the inner core layer, improves the charging capability of the battery monomer, and simultaneously, the metal element can be introduced into the solid electrolyte interface film in the anode active material, reduces the charge transfer impedance of the battery monomer, obviously improves the charging window of the battery monomer and further improves the charging capability of the battery monomer. In some embodiments, at least a portion of the graphite of the outer surface of the inner core layer and at least a portion of the metal silicide of the inner surface of the outer shell layer form a metal silicon carbon compound. According to the technical scheme, the metal silicon carbon compound is provided with the metal-silicon bond and the carbon-silicon bond, wherein the carbon-silicon bond can stabilize the combination of the metal silicon carbon compound and/or the metal silicide metal-silicon bond and graphite, so that the graphite in the inner core layer and the outer shell layer are stably combined, and the charging capability of the battery cell is further improved. In some embodiments, the negative electrode active material has a Dv50 particle size of 1-30 μm, alternatively 5-15 μm. In the technical scheme of the embodiment of the application, the Dv50 particle size of the anode active material is in the range, which is favorable for improving the structural stability of the anode active material, and the diffusion path of active ions in the inner core layer is shorter, so that the charging capability of the battery monomer is comprehensively improved. In some embodiments, the metal element in the metal silicide includes one or more of copper, iron, tantalum, tungsten, hafnium, niobium, vanadium, chromium, magnesium, zirconium, molybdenum, zinc, calcium, or titanium. In the technical scheme of the embodiment of the application, the metal element in the metal silicide has low nucleation sites on one hand and promotes the active sites on the surface of graphite, and on the other hand, the metal element has strong reactivity and high bonding capability with graphite, so that stable metal silicon-carbon compound is easier to form, and the charging capability of the battery monomer is improved as a whole. In some embodiments, the metal silicide has a Dv50 particle size of 5-200nm, alternatively 5-20nm. According to the technical scheme, the Dv50 particle size of the metal silicide is in the range, and the shell layer formed by the metal silicide has a good coating effect on the inner core layer, so that the structural stability of the anode active material is high, the active site on the surface of graphite is improved, and the charging capability of a battery monomer is improved. In some embodiments, the outer shell layer has a mass of 0.1% to 30% based on 100% of the total mass of the inner core layer; the thickness of the outer shell layer is 1-10nm, alternatively 3-7nm. In the technical scheme of the embodiment of the application, the mass of the outer shell layer is in the range relative to the inner core layer, and the thickness of the outer shell layer is set in the range, so that the structural stability of the anode active material can be enhanced, the side reaction of graphite in the inner core layer and electrolyte can be reduced, and further the gram capacity loss of graphite can be reduced. In some