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CN-122025828-A - Battery cell, negative electrode material, preparation method of negative electrode active material and electric device

CN122025828ACN 122025828 ACN122025828 ACN 122025828ACN-122025828-A

Abstract

The application provides a battery monomer, a negative electrode material, a preparation method of the negative electrode material and an electric device. The battery cell comprises a negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode active layer positioned on at least one side of the negative electrode current collector, the negative electrode active layer comprises a negative electrode material, the negative electrode material comprises a negative electrode active material, the negative electrode active material comprises a carbon material and silicon particles, the carbon material is of a shell structure with a hollow inside, the shell structure is provided with a pore canal, and the silicon particles are positioned on the surface of the shell structure and/or in the pore canal. The battery monomer has high energy density, and meanwhile, the dynamic performance and the cycle stability are improved.

Inventors

  • WU KAI
  • SUN XIN
  • YUN LIANG

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (20)

  1. 1. The battery cell comprises a negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode active layer positioned on at least one side of the negative electrode current collector, the negative electrode active layer comprises a negative electrode material, the negative electrode material comprises a negative electrode active material, the negative electrode active material comprises a carbon material and silicon particles, the carbon material is of a shell structure with a hollow inside, the shell structure is provided with a pore canal, and the silicon particles are positioned on the surface and/or in the pore canal of the shell structure.
  2. 2. The battery cell according to claim 1, wherein the BET specific surface area of the negative electrode material is 0.2-30m 2 /g or 0.5-3m 2 /g.
  3. 3. The battery cell according to claim 1 or 2, wherein the average outer diameter of the anode active material is 2-20 μm or 3-13 μm.
  4. 4. A battery cell according to any one of claims 1 to 3, wherein the average thickness of the shell structure is 0.5-8 μm or 1-7 μm.
  5. 5. The battery cell according to any one of claims 1 to 4, wherein the anode active material is spheroid-like, and/or, The sphericity of the negative electrode active material is 0.5-1 or 0.7-1.
  6. 6. The battery cell of any one of claims 1 to 5, characterized by one or more of the following: the particle size of the silicon particles is 0.5-8nm; the average pore diameter of the carbon material is 0.8-5nm; The pore volume of the carbon material is 0.6-1.06cm 3 /g; the BET specific surface area of the carbon material is 1000-2000m 2 /g; The surface density of the negative active layer is 5-9mg/cm 2 .
  7. 7. The battery cell of any one of claims 1 to 6, wherein the mass ratio of the carbon material to the silicon particles is 3:7-8:2.
  8. 8. The battery cell according to any one of claims 1 to 7, wherein the anode active material comprises a core and a coating layer coating the core, the carbon material and the silicon particles are disposed in the core, the coating layer comprises carbon, and/or, The average thickness of the coating layer is 1-2nm.
  9. 9. The negative electrode material comprises a negative electrode active material, wherein the negative electrode active material comprises a carbon material and silicon particles, the carbon material is of a shell structure with a hollow inside, the shell structure is provided with pore channels, and the silicon particles are positioned on the surface of the shell structure and/or in the pore channels.
  10. 10. The anode material according to claim 9, wherein the BET specific surface area of the anode material is 0.2 to 30m 2 /g or 0.5 to 3m 2 /g.
  11. 11. The anode material according to claim 9 or 10, wherein the anode active material has an average outer diameter of 2 to 20 μm or 3 to 13 μm.
  12. 12. The anode material according to any one of claims 9 to 11, wherein the average thickness of the shell structure is 0.5-8 μm or 1-7 μm.
  13. 13. The negative electrode material according to any one of claims 9 to 12, wherein the negative electrode active material is spheroid-like, and/or, The sphericity of the negative electrode active material is 0.5-1 or 0.7-1.
  14. 14. The anode material according to any one of claims 9 to 13, characterized by one or more of the following: the particle size of the silicon particles is 0.5-8nm; the average pore diameter of the carbon material is 0.8-5nm; The pore volume of the carbon material is 0.6-1.06cm 3 /g; the BET specific surface area of the carbon material is 1000-2000m 2 /g; The mass ratio of the carbon material to the silicon particles is 3:7-8:2.
  15. 15. The negative electrode material according to any one of claims 9 to 14, wherein the negative electrode active material comprises a core and a coating layer coating the core, the carbon material and the silicon particles being disposed in the core, the coating layer comprising carbon, and/or, The average thickness of the coating layer is 1-2nm.
  16. 16. A method of preparing a negative electrode material comprising the steps of: mixing resin containing a cyclic structure, a curing agent and a water-in-oil emulsifier with an oil phase solvent to obtain a first mixture; adding an aqueous phase solvent into the first mixture and mixing to obtain a water-in-oil emulsion; Mixing a hydrophilic surfactant, an oil-in-water type emulsifier and a curing agent with an aqueous phase solvent to obtain a second mixture; Adding the water-in-oil emulsion to the second mixture and mixing to obtain an oil-in-water-in-oil emulsion; carrying out a solidification reaction on the oil-in-water-in-oil emulsion, carrying out solid-liquid separation, and collecting a solid phase substance; Drying, roasting and pore-forming the solid phase substance to obtain a carbon material; taking the carbon material as a base material, and adopting a silicon source to carry out vapor deposition to obtain a negative electrode material; The cathode material comprises a cathode active material, the cathode active material comprises a carbon material and silicon particles, the carbon material is of a shell structure with a hollow inside, the shell structure is provided with pore channels, and the silicon particles are positioned on the surface of the shell structure and/or in the pore channels.
  17. 17. The method of claim 16, wherein in the step of preparing the water-in-oil emulsion: Pre-reacting after mixing to obtain water-in-oil emulsion, and/or, The pre-reaction temperature is 70-120 ℃, and/or, The pre-reaction time is 0-60min.
  18. 18. The method according to claim 16 or 17, wherein in the step of preparing the carbon material: the temperature of the calcination is 900-980 ℃, and/or, The roasting time is 4-8h, and/or, The pore-forming is water vapor pore-forming.
  19. 19. The method according to any one of claims 16 to 18, wherein in the step of preparing the solid phase: the temperature of the curing reaction is the curing temperature of the resin containing the cyclic structure, and/or, The curing reaction time is 3-12h.
  20. 20. The method according to any one of claims 16 to 19, characterized by one or more of the following: in the step of preparing the first mixture, the mass ratio of the resin containing the cyclic structure to the oil phase solvent is 10:4-10:0.5. In the step of preparing the water-in-oil emulsion, the mass ratio of the aqueous phase solvent to the first mixture is 1:16.28-7:16.28; In the step of preparing the oil-in-water-in-oil emulsion, the mass ratio of the oil-in-water emulsion to the second mixture is 10:122-30:122.

Description

Battery cell, negative electrode material, preparation method of negative electrode active material and electric device Technical Field The application relates to the technical field of batteries, in particular to a battery monomer, a negative electrode material, a preparation method of a negative electrode active material and an electric device. Background In recent years, as the application range of the battery is wider and wider, the battery is widely applied to energy storage power supply systems such as hydraulic power, firepower, wind power, solar power stations and the like, and a plurality of fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, military equipment, aerospace and the like. As batteries have been greatly developed, higher demands are also being made on energy density, cycle performance, and kinetic performance. Disclosure of Invention The present application has been made in view of the above problems, and an object thereof is to provide a battery cell, a negative electrode material, a method for producing the negative electrode material, and an electric device. The battery cell of the application has high energy density, and simultaneously, the dynamic performance and the cycle stability of the battery cell are improved. In order to achieve the above object, a first aspect of the present application provides a battery cell, including a negative electrode tab, where the negative electrode tab includes a negative electrode material, where the negative electrode material includes a negative electrode active material, where the negative electrode active material includes a carbon material and silicon particles, where the carbon material is a shell structure with a hollow interior, where the shell structure is provided with a pore channel, and where the silicon particles are located on a surface of and/or in the pore channel of the shell structure. Therefore, the application improves the energy density of the battery unit, reduces the DCR of the battery unit, shortens the charging time and improves the dynamic performance of the battery unit by the carbon material with the internal hollow shell structure and the negative electrode active material formed by the silicon particles positioned on the surface of the carbon material and/or in the shell pore canal, and the internal hollow provides space for the volume expansion of the silicon particles, reduces the volume change of the negative electrode plate and further improves the cycle stability of the battery unit. In any embodiment, the negative electrode material has a BET specific surface area of 0.2 to 30m 2/g or 0.5 to 3m 2/g. Therefore, on one hand, more channels are provided for lithium ion transmission, the dynamic performance of the battery monomer is improved, and on the other hand, the energy density of the battery monomer is improved, the side reaction of the negative electrode plate is restrained, and the cycling stability of the battery monomer is improved. In any embodiment, the average outer diameter of the anode active material is 2 to 20 μm or 3 to 13 μm. Therefore, on one hand, the DCR of the battery cell is reduced, the dynamic performance of the battery cell is improved, and on the other hand, the negative influence of the too small outer diameter on the energy density and the cycle stability of the battery cell is reduced. In any embodiment, the average thickness of the shell structure is 0.5-8 μm or 1-7 μm. Therefore, on the premise of ensuring the energy density of the battery monomer, on one hand, the transmission path of lithium ions is shortened, the dynamic performance of the battery monomer is improved, and on the other hand, a space is reserved for the volume expansion of silicon, and the cycle stability of the battery monomer is improved. In any embodiment, the anode active material is spheroid-like, and/or the anode active material has a sphericity of 0.5-1 or 0.7-1. Thereby reducing the crushing degree of the anode active material particles and enhancing the strength of the anode active material particles. In any embodiment, the silicon particles have a particle size of 0.5 to 8nm. Thus, the expansion of the volume of the silicon particles is suppressed while the energy density of the battery cell is ensured, thereby improving the cycle stability of the battery cell. In any embodiment, the carbon material has an average pore size of 0.8 to 5nm. In any embodiment, the carbon material has a pore volume of 0.6 to 1.06cm 3/g. In any embodiment, the carbon material has a BET specific surface area of 1000 to 2000m 2/g. Therefore, the average pore diameter, pore volume and/or specific surface area of the carbon material are within the above ranges, so that a larger accommodating space is provided for the silicon particles, the energy density of the battery monomer is improved, meanwhile, enough space is reserved for the expansion of the silicon particles, the side reaction of