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CN-122029642-A - Battery monomer, battery device and power utilization device

CN122029642ACN 122029642 ACN122029642 ACN 122029642ACN-122029642-A

Abstract

The disclosure provides a battery cell, a battery device and an electricity consumption device, wherein the battery cell comprises a positive electrode plate, the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, the porosity of the positive electrode film layer is 10% -25%, the positive electrode film layer comprises positive electrode active material particles and a conductive agent, the conductive agent comprises a one-dimensional conductive agent, the positive electrode film layer is arranged in a section of the positive electrode plate in the thickness direction, and the number of positive electrode active material particles connected by the one-dimensional conductive agent is 20% -100%.

Inventors

  • DAI ZHIPENG
  • JIN CHAO
  • TAN JUE
  • LI BAIQING
  • ZHANG XIN
  • CHEN SHUAI
  • WU JIANXIONG

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20250318

Claims (20)

  1. 1. A battery cell is characterized by comprising a positive pole piece, The positive pole piece comprises a positive current collector and a positive film layer arranged on at least one side of the positive current collector, wherein the porosity of the positive film layer is 10% -25%; The positive electrode film layer comprises positive electrode active material particles and a conductive agent; The conductive agent comprises a one-dimensional conductive agent, and in a section of the positive electrode film layer along the thickness direction of the positive electrode plate, the number of positive electrode active material particles connected by the one-dimensional conductive agent among the positive electrode active material particles is 20% -100%.
  2. 2. The battery cell according to claim 1, wherein in a tangential plane of the positive electrode film layer in a thickness direction of the positive electrode sheet, the number of positive electrode active material particles in which the one-dimensional conductive agent is present between the positive electrode active material particles is 50% -100%.
  3. 3. The battery cell of claim 1 or 2, wherein the positive electrode film layer has a porosity of 16% -19%.
  4. 4. A battery cell according to any one of claims 1 to 3, wherein the one-dimensional conductive agent is present in an amount of 0.1% to 1%, optionally 0.2% to 0.5% by mass based on the total mass of the positive electrode film layer.
  5. 5. The battery cell according to any one of claims 1 to 4, wherein the mass content of the conductive agent is 0.5% to 1.5%, optionally 0.8% to 1.2%, based on the total mass of the positive electrode film layer.
  6. 6. The battery cell according to any one of claims 1 to 5, wherein the positive electrode active material particles include a lithium-containing transition metal oxide, and wherein a molar ratio of nickel element in the lithium-containing transition metal oxide is 40% to 95% based on a total molar number of transition metals in the lithium-containing transition metal oxide.
  7. 7. The battery cell of any one of claims 1 to 6, wherein the positive electrode active material comprises Li a Ni x Co y M1 z M2 b O c , wherein 0.6≤a≤ 1.2,0.4≤x≤0.95, 0< y≤0.3, 0< z <0.5, 0≤b <0.5,1.9≤c≤2.1, wherein M1 comprises one or more of Mn, al, and M2 comprises one or more of Al, na, K, ca, ba, sb, ti, zr, W, sr, nb, mo, si, mg, B, cr, ta and Y.
  8. 8. The battery cell according to any one of claims 1 to 7, wherein the particle size distribution of the particles in the positive electrode film layer is a bimodal distribution as determined by a laser diffraction method.
  9. 9. The battery cell of claim 8, wherein the particles in the positive electrode layer have a particle size distribution pattern with a first peak to peak position of 1.5 μm to 5 μm, optionally 2.5 μm to 3 μm, and/or a second peak to peak position of 5 μm to 13 μm, optionally 7 μm to 11 μm.
  10. 10. The battery cell according to any one of claims 1 to 7, wherein the particle size distribution of the particles in the positive electrode film layer is measured by a laser diffraction method as a unimodal distribution, the peak position being located between 2 μm and 5 μm.
  11. 11. The battery cell according to any one of claims 1 to 10, wherein the positive electrode active material particles comprise single crystal particles.
  12. 12. The battery cell of claim 11, wherein the single crystal particles have a D v50 of 2 μιη to 5 μιη and the single crystal particles have a (D v90 -D v10 )/D v50 of 1.2 to 1.7.
  13. 13. The battery cell of claim 11 or 12, wherein the positive electrode active material particles further comprise polycrystalline particles.
  14. 14. The battery cell of claim 13, wherein the polycrystalline particles have a D v50 μm to 15 μm and the polycrystalline particles have a (D v90 -D v10) /D v50 of 1.1 to 1.4.
  15. 15. The battery cell of claim 13 or 14, wherein the mass ratio of the single crystal particles to the polycrystalline particles is 1:9-5:5.
  16. 16. The battery cell according to any one of claims 1 to 15, wherein at least part of the surface of the positive electrode active material is provided with a coating layer comprising a metal oxide or metal fluoride, optionally one or more of alumina, titania, tungsten oxide, niobium oxide, boron oxide, molybdenum oxide, lithium fluoride, aluminum fluoride.
  17. 17. The battery cell of any one of claims 1 to 16, wherein the one-dimensional conductive agent comprises one or more of carbon nanotubes, carbon nanofibers, graphene nanoribbons, metal nanowires, metal oxide nanowires.
  18. 18. The battery cell of any one of claims 1 to 17, wherein the one-dimensional conductive agent is a carbon nanotube conductive agent.
  19. 19. The battery cell of claim 18, wherein the carbon nanotube conductive agent comprises one or more of single-walled carbon nanotubes, few-walled carbon nanotubes, multi-walled carbon nanotubes.
  20. 20. The battery cell of claim 19, wherein the single-walled carbon nanotubes have a wall layer number of 1 layer and a tube diameter of 2nm-5nm.

Description

Battery monomer, battery device and power utilization device Technical Field The present application relates to the field of battery technologies, and in particular, to a battery unit, a battery device, and an electric device. Background In recent years, battery cells are widely used in energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, and in various fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, military equipment, aerospace and the like. Some electric devices requiring frequent charge and discharge, such as small battery electric BEV models, hybrid HEV models, unmanned aerial vehicles, energy storage stations, and the like. Batteries are both of sufficient capacity to support the operation of the powered device and are subject to frequent charge and discharge cycles, thus placing a higher demand on the performance of the battery cells. Disclosure of Invention The present application has been made in view of the above-described problems, and an object of the present application is to provide a battery cell having a positive electrode film layer structure that improves the power performance of the battery and has a high retention capacity of the power performance during the cycle while maintaining a high energy density. The first aspect of the application provides a battery monomer, which comprises a positive electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, the porosity of the positive electrode film layer is 10% -25%, the positive electrode film layer comprises positive electrode active material particles and a conductive agent, the conductive agent comprises a one-dimensional conductive agent, and the number of the positive electrode active material particles connected by the one-dimensional conductive agent is 20% -100% in a section of the positive electrode film layer along the thickness direction of the positive electrode plate. In the embodiment of the application, the energy density of the battery can be kept at a higher level and the expansion and contraction of the pole piece can be reduced by controlling the porosity of the positive electrode film layer within the range. And through adding one-dimensional conductive agent, the one-dimensional conductive agent is connected among the particles of the positive electrode active material, even at a larger pore, the one-dimensional conductive agent can realize crossing due to the characteristic of extremely high length-diameter ratio of the one-dimensional conductive agent, a conductive bridge is constructed, the connection can be kept under an expansion state, the conductivity of the inside of the positive electrode film layer is improved, and further, the improvement of the power performance of the battery and the maintenance in the circulating process are realized on the basis of keeping high energy density. In any embodiment, in the section of the positive electrode film layer along the thickness direction of the positive electrode sheet, the number of positive electrode active material particles connected by the one-dimensional conductive agent between the positive electrode active material particles is 50% -100%. The conductive network among the positive electrode active material particles in the positive electrode film layer is further formed, and a plurality of connecting particles possibly exist in each particle, so that the conductivity is enhanced, the probability of maintaining connection after expansion is improved, and the power performance of the battery is further improved. In any embodiment, the positive electrode film layer has a porosity of 16% to 19%. The electrolyte can fully infiltrate the positive electrode active material particles, and meanwhile, the occurrence of oversized pores is avoided, so that one-dimensional conductive agent connection is easier to form among the positive electrode active material particles, and the power performance of the battery is further improved. The smaller porosity is beneficial to inhibiting the expansion of the positive electrode plate and improving the degradation of power performance in the cycle process of the battery. In any embodiment, the one-dimensional conductive agent is present in an amount of 0.1% to 1%, alternatively 0.2% to 0.5%, based on the total mass of the positive electrode film layer. The mass content of the one-dimensional conductive agent is in the range, so that the positive electrode film layer has good electron conductivity and processability. In any embodiment, the conductive agent is present in an amount of 0.5% to 1.5%, alternatively 0.8% to 1.2%, by mass based on the total mass of the positive electrode film layer. The mass content of the conductive agent is in the range, so that the electron conductiv