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CN-122000428-A - Battery cell

CN122000428ACN 122000428 ACN122000428 ACN 122000428ACN-122000428-A

Abstract

The invention provides a battery, which comprises a positive plate, wherein the positive plate comprises a positive material layer, the positive material layer comprises a positive material, the positive material comprises a positive active material and a lithium supplementing material, the positive active material comprises lithium iron phosphate, the lithium supplementing material comprises Li 2 C n O n+2 , wherein n is an integer greater than or equal to 1 or at least one of Li 2 O, a high-voltage platform is included in a battery charging curve, the voltage corresponding to the high-voltage platform is 3.9-4.7V, the slope of the high-voltage platform is a, the average particle size Dv50 of the positive material is b mu m, and the a and b meet the relational expression shown in the formula I, namely a multiplied by b is greater than or equal to 0.016 and less than or equal to 1.6 formula I. The battery provided by the invention can give consideration to both quick charge performance and cycle life.

Inventors

  • SHAN XUYI
  • XIONG YALI
  • QIN KAIYAN
  • MA JIE
  • MA GUOHUA
  • HE BAOTAN
  • LI ZHUYUAN
  • XIE YINGYING

Assignees

  • 中创新航科技集团股份有限公司

Dates

Publication Date
20260508
Application Date
20251230

Claims (20)

  1. 1. A battery comprising a positive electrode sheet, the positive electrode sheet comprising a positive electrode material layer, the positive electrode material layer comprising a positive electrode material, the positive electrode material comprising a positive electrode active material and a lithium-supplementing material, the positive electrode active material being selected from lithium iron phosphate, the lithium-supplementing material comprising Li 2 C n O n+2 , wherein n is an integer greater than or equal to 1, or at least one of Li 2 O; the battery charging curve comprises a high-voltage platform, the voltage corresponding to the high-voltage platform is 3.9-4.7V, and the slope of the high-voltage platform is a; The average particle diameter Dv50 of the positive electrode material is b mu m; The a and b satisfy the relation shown in the formula I: A multiplied by b is more than or equal to 0.016 and less than or equal to 1.6.
  2. 2. The battery of claim 1, wherein 0.1 +.a x b +.0.8.
  3. 3. The battery according to claim 1, wherein the value of a ranges from 0.06 to 1 and/or the value of b μm ranges from 0.2 to 2 μm.
  4. 4. The battery according to claim 1, wherein the value of a ranges from 0.1 to 0.8 and/or the value of b μm ranges from 0.8 to 1.2 μm.
  5. 5. The battery of claim 1, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer composited on a surface of the positive electrode current collector; the positive current collector comprises an aluminum foil substrate and a carbon layer compounded on the surface of the aluminum foil substrate.
  6. 6. The battery of claim 5, wherein the carbon layer has a thickness of 1-4 μm.
  7. 7. The battery according to claim 5, wherein the mass ratio of the carbon layer to the aluminum foil in the positive electrode current collector is 0.002-0.005.
  8. 8. The battery of claim 1, wherein the lithium-compensating material comprises at least one of Li 2 C 2 O 4 、Li 2 C 3 O 5 、Li 2 C 4 O 6 、Li 2 CO 3 、Li 2 O.
  9. 9. The battery of claim 1, wherein the lithium-compensating material is selected from the group consisting of Li 2 C 2 O 4 , and a has a value in the range of 0.1 to 0.8.
  10. 10. The battery of claim 1, wherein the lithium-compensating material further comprises a catalyst selected from one or more of Co 3 O 4 、Fe 2 O 3 、NiO、MnO 2 、CuO、TiO 2 、ZnO、Mo 2 C、V 2 O 5 and CeO 2 .
  11. 11. The battery according to claim 10, wherein the mass content of the catalyst in the positive electrode material layer is in the range of 0.1% -0.5%.
  12. 12. The battery of claim 1, wherein the positive electrode sheet has a compacted density of 2.5-2.7 g/cm 3 .
  13. 13. The battery of claim 5, wherein the positive electrode material layer includes a doping element therein, the doping element being selected from at least one of Ti, V, mg, al, mn, zn, mo.
  14. 14. The battery according to claim 13, wherein the doping element is doped in the positive electrode material layer in an amount of 2000 to 5000ppm.
  15. 15. The battery according to claim 1, wherein a coating layer is arranged on the surface of the lithium iron phosphate, and the thickness of the coating layer is 2-10 nm.
  16. 16. The battery of claim 1, wherein the battery comprises a negative electrode sheet comprising a negative electrode material layer comprising a negative electrode material comprising a negative electrode active material selected from at least one of graphite, a silicon-based material.
  17. 17. The battery of claim 16, wherein the negative electrode material has a particle size Dv50 of 5-15um.
  18. 18. The battery of claim 1, further comprising an electrolyte having a viscosity in the range of 2 to 5 mpa-s.
  19. 19. The battery according to claim 18, wherein the electrolyte comprises a solvent selected from at least one of Ethylene Carbonate (EC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), and dimethyl carbonate (DMC), and the mass ratio of the solvent in the electrolyte is 80% -90%.
  20. 20. The battery of claim 18, wherein the electrolyte comprises an additive selected from at least one of vinylene carbonate and fluoroethylene carbonate, and wherein the additive is present in the electrolyte in an amount ranging from 0.1% to 5%.

Description

Battery cell Technical Field The invention belongs to the technical field of batteries, and particularly relates to a battery. Background The cathode material in a lithium ion battery irreversibly consumes active lithium due to the formation of a Solid Electrolyte Interface (SEI) film during the first charge and discharge, resulting in a decrease in the cycle life of the battery. To compensate for this loss, it is often necessary to introduce a lithium-compensating material into the battery system to provide an additional source of active lithium. Lithium oxalate (Li 2C2O4) is of interest as a potential lithium supplementing material due to its high theoretical capacity and relatively low decomposition temperature. However, li 2C2O4 still has the following problems in practical applications: The lithium oxalate has a high lithium removal platform (> 4.4V vs. Li +/Li), and the high voltage can exacerbate polarization inside the battery, resulting in a continuous increase in the internal resistance of the battery. And the voltage exceeds the tolerance limit of electrolyte, which causes the electrolyte to oxidize and decompose to cause aluminum foil corrosion, and the problems finally cause the reduction of the quick charge performance and the cycle life of the battery. Therefore, providing a battery that combines both battery fast charge performance and cycle life is a problem to be solved. Disclosure of Invention In view of the above, the present invention aims to provide a battery with high fast charge performance and long cycle life. The invention provides a battery, which comprises a positive plate, wherein the positive plate comprises a positive material layer, the positive material layer comprises a positive material, the positive material comprises a positive active material and a lithium supplementing material, the positive active material comprises lithium iron phosphate, the lithium supplementing material comprises Li 2CnOn+2, wherein n is an integer greater than or equal to 1 or at least one of Li 2 O, a high-voltage platform is included in a battery charging curve, the voltage corresponding to the high-voltage platform is 3.9-4.7V, the slope of the high-voltage platform is a, the average particle size Dv50 of the positive material is b mu m, and the a and b meet the relational expression shown in the formula I, namely a multiplied by b is greater than or equal to 0.016 and less than or equal to 1.6 formula I. Compared with the prior art, the battery provided by the invention can be provided with both fast charge performance and cycle life. Drawings Fig. 1 is a charge curve of a battery, 3.9-4.7V corresponding to a high voltage plateau for lithium replenishment agent. Detailed Description The invention provides a battery, which comprises a positive plate, wherein the positive plate comprises a positive material layer, the positive material layer comprises a positive material, the positive material comprises a positive active material and a lithium supplementing material, the positive active material is selected from lithium iron phosphate, the lithium supplementing material comprises Li 2CnOn+2, wherein n is an integer greater than or equal to 1, or at least one of Li 2 O; the battery charging curve comprises a high-voltage platform, the voltage corresponding to the high-voltage platform is 3.9-4.7V, and the slope of the high-voltage platform is a; The average particle diameter Dv50 of the positive electrode material is b mu m; The a and b satisfy the relation shown in the formula I: A multiplied by b is more than or equal to 0.016 and less than or equal to 1.6. In the invention, when a and b meet the relation shown in the formula I, the battery has higher quick charge performance and cycle life. The slope of the high-voltage platform is controlled, so that the positive electrode material can be prevented from being subjected to lithium removal reaction too severely, heat accumulation caused by too fast reaction rate is reduced, polarization is further reduced, and quick charge performance is improved. The stability and the integrity of SEI film generated by the negative electrode can be ensured, so that the side reaction between the electrolyte and the interface of the negative electrode is reduced, and the cycle life of the battery is improved. When a is too large, the polarization of lithium oxalate is aggravated, the deintercalation of lithium ions is difficult, the rapid charging performance is reduced, and the rapid charging performance can be improved by regulating and controlling the average particle size Dv50 of the positive electrode material. The average particle diameter Dv50 of the positive electrode material is controlled, so that the transmission path of lithium ions can be shortened, the quick charge performance of the battery can be improved, the contact area with electrolyte can be reduced, side reactions can be reduced, and the cycle life of the battery can be prolonged. Therefor