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CN-122029657-A - Battery monomer and electricity utilization device

CN122029657ACN 122029657 ACN122029657 ACN 122029657ACN-122029657-A

Abstract

The application provides a battery unit and an electricity utilization device, wherein the battery unit comprises a positive electrode plate, a negative electrode plate and a separation film arranged between the positive electrode plate and the negative electrode plate, the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side surface of the positive electrode current collector, the positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises lithium-containing phosphate, the surface density of the positive electrode film layer is 0.35g/1540.25mm 2 to 0.5g/1540.25mm 2 , the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side surface of the negative electrode current collector, the surface density of the negative electrode film layer is 0.13g/1540.25mm 2 to 0.19g/1540.25mm 2 , the negative electrode film layer comprises a negative electrode active material, and the silicon element accounts for 2-10% of the negative electrode active material based on the mass of the negative electrode active material.

Inventors

  • WEI XICHEN
  • LUO YUYING
  • ZHAO YUZHEN

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20240830
Priority Date
20240802

Claims (20)

  1. A battery cell is characterized in that the battery cell comprises a positive pole piece, a negative pole piece and an isolating film arranged between the positive pole piece and the negative pole piece, The positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side surface of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises lithium-containing phosphate, and the surface density of the positive electrode film layer is 0.35g/1540.25mm 2 to 0.5g/1540.25mm 2 ; the negative electrode plate comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side surface of the negative electrode current collector, wherein the surface density of the negative electrode film layer on one side is 0.13g/1540.25mm 2 to 0.19g/1540.25mm 2 , the negative electrode film layer comprises a negative electrode active material, the negative electrode active material comprises a material containing silicon element, and the mass ratio of the silicon element based on the negative electrode active material is 2-10%.
  2. The battery cell according to claim 1, wherein the silicon element is 4% to 8% by mass based on the negative electrode active material.
  3. The battery cell according to claim 1 or 2, wherein the anode active material comprises a silicon-based material and a carbon-based material, The silicon-based material comprises one or more of silicon-carbon composite, silicon oxygen compound, and/or The carbon-based material comprises one or more of artificial graphite and natural graphite.
  4. The battery cell of any one of claims 1-3, further comprising an electrolyte comprising an organic solvent comprising a carbonate solvent comprising one or more of dimethyl carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, and ethylmethyl carbonate.
  5. The battery cell according to claim 4, wherein the organic solvent comprises dimethyl carbonate, the mass ratio of the dimethyl carbonate being 4% to 20% based on the total mass of the electrolyte.
  6. The battery cell according to claim 4, wherein the organic solvent comprises dimethyl carbonate, and the mass ratio of the dimethyl carbonate is 8% to 16% based on the total mass of the electrolyte.
  7. The battery cell of any one of claims 1-6, wherein the electrolyte further comprises an additive comprising a carbonate additive; the carbonate additive comprises one or more of fluoroethylene carbonate, vinylene carbonate, and 1, 3-propane sultone.
  8. The battery cell according to claim 7, wherein the additive comprises fluoroethylene carbonate in an amount of 5 to 30% by mass of the fluoroethylene carbonate in the electrolyte based on the total mass of the electrolyte.
  9. The battery cell according to claim 7, wherein the additive comprises fluoroethylene carbonate in an amount of 5 to 15% by mass of fluoroethylene carbonate in the electrolyte based on the total mass of the electrolyte.
  10. The battery cell of any one of claims 4-9, wherein the electrolyte has a conductivity of 9mS/cm to 14mS/cm.
  11. The battery cell according to any one of claims 1 to 10, wherein in a cross section of the positive electrode film layer in a thickness direction, the lithium-containing phosphate includes lithium-containing phosphate particles having a longest diameter of 1 μm to 5 μm and lithium-containing phosphate particles having a longest diameter of 0.1 μm to 0.3 μm.
  12. The battery cell of any one of claims 1-11, wherein the lithium-containing phosphate has a general formula of formula I, li x A y Me a M b P 1-c X c Y z formula I, Wherein X is more than or equal to 0.1 and less than or equal to 1.3, Y is more than or equal to 0 and less than or equal to 1.3, x+y is more than or equal to 0.9 and less than or equal to 1.3, a is more than or equal to 0.9 and less than or equal to 1.5, b is more than or equal to 0.9 and less than or equal to 0.5, a+b is more than or equal to 0.9 and less than or equal to c and less than or equal to 0.5, z is more than or equal to 3 and less than or equal to 5;A and comprises one or more of Na, K and Mg, me comprises one or more of Mn, fe, co, ni, M comprises one or more of B, mg, al, si, P, S, ca, sc, ti, V, cr, cu, zn, sr, Y, zr, nb, mo, cd, sn, sb, te, ba, ta, W, yb, la, ce, X comprises one or more of S, si, cl, B, C, N, and Y comprises one or more of O, F.
  13. The battery cell of any one of claims 1-12, wherein the positive electrode film layer comprises a lithium-compensating material comprising one or more of ternary materials, lithium phosphate, lithium ferrite, lithium nickelate, dilithium phosphate, lithium sulfate, lithium sulfite, lithium molybdate, lithium oxalate, lithium titanate, lithium tetraborate, lithium metasilicate, lithium metamanganate, lithium tartrate, and trilithium citrate.
  14. The battery cell of claim 13, wherein at least a portion of the surface of the lithium-compensating material has a coating thereon.
  15. The battery cell of claim 14, wherein the coating comprises a carbon-containing coating having a thickness of 10nm to 200nm.
  16. The battery cell of claim 14, wherein a gap is provided between the lithium-compensating material and the carbon-containing coating layer, the gap having a width of 5nm to 50nm.
  17. The battery cell of any one of claims 13 to 16, wherein the longest diameter of the lithium-compensating material is 5 μιη to 20 μιη.
  18. The battery cell of any one of claims 13 to 16, wherein the longest diameter of the lithium-compensating material is 6 μιη to 12 μιη.
  19. The battery cell of any one of claims 13 to 18, wherein the mass fraction of the lithium-compensating material is 0.2% to 2% based on the total mass of the positive electrode film layer.
  20. The battery cell of claim 19, wherein the lithium-compensating material comprises 0.1% to 1% by mass based on the total mass of the positive electrode film layer.

Description

Battery monomer and electricity utilization device Cross reference PCT International patent application No. PCT/CN2024/109591, entitled "Battery cell and Power device" filed on 8/2 of 2024, is incorporated herein by reference in its entirety. Technical Field The application relates to the technical field of battery monomers, in particular to a battery monomer 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. With the popularization of single battery applications, higher requirements are also put on the dynamic performance, the cycle performance, the service life and the like. Disclosure of Invention The present application has been made in view of the above problems, and an object of the present application is to provide a novel battery cell having a high energy density and excellent both of quick charge performance and cycle performance. In order to achieve the above object, a first aspect of the present application provides a battery cell, the battery cell including a positive electrode tab, a negative electrode tab, and a separator disposed between the positive electrode tab and the negative electrode tab, wherein the positive electrode tab includes a positive electrode current collector and a positive electrode film layer disposed on at least one side surface of the positive electrode current collector, the positive electrode film layer includes a positive electrode active material including lithium-containing phosphate, the surface density of the single-sided positive electrode film layer is 0.35g/1540.25mm 2 to 0.5g/1540.25mm 2, the negative electrode tab includes a negative electrode current collector and a negative electrode film layer disposed on at least one side surface of the negative electrode current collector, the surface density of the single-sided negative electrode film layer is 0.13g/1540.25mm 2 to 0.19g/1540.25mm 2, the negative electrode film layer includes a negative electrode active material including a silicon-containing material, and the silicon content is 2% to 10% based on the mass of the negative electrode active material. In the battery monomer, the lithium-containing phosphate with the surface density in the range is adopted in the positive electrode film layer, so that the problem of low energy density when the lithium-containing phosphate is used as a positive electrode active material can be effectively solved, the basic charging capacity of the battery can be maintained, the energy density and the charging performance of the battery can be improved, meanwhile, the negative electrode active material containing silicon element in the range is adopted in the negative electrode film layer, the gram capacity of the negative electrode can be effectively improved, and the quick charging performance of the battery can be improved when the surface density in the range is adopted. In addition, through the mutual matching of the positive electrode film layer and the negative electrode film layer under proper surface density proportion, the problem of lithium precipitation can be better improved, so that the battery monomer has higher energy density, better charging capacity and better cycle performance, and the battery performance is comprehensively improved. In any embodiment, the silicon element accounts for 4 to 8% based on the mass of the anode active material. When the negative electrode active material containing silicon element in the above range is used in the negative electrode film layer, it is possible to further improve both the energy density and the charging performance of the battery. In any embodiment, the negative electrode active material includes a silicon-based material including one or more of a silicon-carbon composite, a silicon-oxygen compound, and/or a carbon-based material including one or more of artificial graphite, natural graphite. When the graphite-based carbon-based material is used as a negative electrode active material, the graphite-based carbon-based material has better electrochemical performance, longer cycle life and lower cost, and when the silicon-based material is used together with the graphite-based carbon-based material, the gram capacity of the negative electrode active material can be further improved on the basis. In any embodiment, the battery cell further comprises an electrolyte, the electrolyte comprising an organic solvent comprising a carbonate solvent comprising one or more of dimethyl carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, and ethylmethyl carbonate. When the electrolyte is matched with the positive and negative electrode film layers with the surface density, the problem of the infiltration of the electrode