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CN-122025739-A - Lithium ion secondary battery, battery device, and electricity using device

CN122025739ACN 122025739 ACN122025739 ACN 122025739ACN-122025739-A

Abstract

The application provides a lithium ion secondary battery, a battery device and an electric device. The lithium ion secondary battery comprises a positive electrode plate, a negative electrode plate and an electrolyte, 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 positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises lithium-containing transition metal phosphate particles at least part of the surfaces of which are provided with carbon coating materials, the positive electrode film layer is subjected to graphitization degree C value accumulation distribution curves obtained under a laser micro-confocal Raman spectrometer surface scanning mode, the median C 50 of graphitization degree is more than or equal to 0.95 and less than or equal to 1.20, the concentration degree of C value (C 90 -C 10 )/C 50 is 0.01-0.04), wherein the graphitization degree C value is I G /I D ,I G and represents the G peak intensity of a Raman spectrum at 1580+/-100 cm ‑1 , and I D represents the D peak intensity of the Raman spectrum at 1350+/-100 cm ‑1 .

Inventors

  • LI XIAOJING
  • LI JIA
  • ZHANG XIAOFENG
  • JIA XIAOYANG
  • LIU HONGYU
  • BIE CHANGFENG
  • CHEN SHENG
  • LIANG YULI
  • NI HUAN
  • LIU NA
  • Ye Xinde

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20250423
Priority Date
20250328

Claims (20)

  1. 1. A lithium ion secondary battery is characterized by comprising a positive electrode plate, a negative electrode plate and electrolyte, Wherein 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, The positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises lithium-containing transition metal phosphate particles at least part of the surfaces of which are provided with carbon coating materials, In a graphitization degree C value accumulation distribution curve obtained by the positive electrode film layer in a laser micro-confocal Raman spectrometer surface scanning mode, a median C 50 of graphitization degree is more than or equal to 0.95 and less than or equal to 1.20, and the concentration degree of C value (C 90 -C 10 )/C 50 is 0.01-0.04; Wherein, the graphitization degree C value is I G /I D ,I G , which represents the G peak intensity of the Raman spectrum at 1580+/-100 cm -1 , and I D , which represents the D peak intensity of the Raman spectrum at 1350+/-100 cm -1 .
  2. 2. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a graphitization degree C 50 of 0.96 to 1.15 in a graphitization degree C value cumulative distribution curve obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  3. 3. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a graphitization degree C 50 of 0.98 to 1.13 in a graphitization degree C value cumulative distribution curve obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  4. 4. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a concentration of C value (C 90 -C 10 )/C 50 is 0.02 to 0.038 in a cumulative distribution curve of C value of graphitization degree obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  5. 5. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a concentration of C value (C 90 -C 10 )/C 50 is 0.02 to 0.036 in a cumulative distribution curve of C value of graphitization degree obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  6. 6. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a graphitization degree C 90 of 1.0 to 1.30 in a cumulative distribution curve of graphitization degree C values obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  7. 7. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a graphitization degree C 90 of 1.02 to 1.15 in a cumulative distribution curve of graphitization degree C values obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  8. 8. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a graphitization degree C 10 of 0.92 to 1.10 in a cumulative distribution curve of graphitization degree C values obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  9. 9. The lithium ion secondary battery according to claim 1, wherein the positive electrode film layer has a graphitization degree C 10 of 0.98-1.08 in a cumulative distribution curve of graphitization degree C values obtained in a laser micro-confocal raman spectrometer surface scanning mode.
  10. 10. The lithium ion secondary battery according to claim 1, wherein the area ratio of the particles having an area of 0.001 μm 2 -0.06μm 2 in a section of the positive electrode film layer in the thickness direction of the electrode sheet is 21.00% to 27.00%, and the area ratio of the particles having an area of 1.0 μm 2 -4.0μm 2 is 12.00% to 20.00%.
  11. 11. The lithium ion secondary battery according to claim 1, wherein D A50 of the particles in the section of the positive electrode film layer in the thickness direction of the electrode sheet is 600nm to 800nm, wherein D A50 is the particle diameter corresponding to the cumulative area distribution of the particles reaching 50% in the cumulative area distribution curve of the particles.
  12. 12. The lithium ion secondary battery according to claim 11, wherein D A50 of the particles in the section of the positive electrode film layer in the thickness direction of the electrode sheet is 650nm to 750nm, wherein D A50 is the particle diameter corresponding to the cumulative area distribution of the particles reaching 50% in the cumulative area distribution curve of the particles.
  13. 13. The lithium ion secondary battery according to claim 1, wherein in the particle roughness area cumulative distribution curve obtained by the section of the positive electrode film layer in the thickness direction of the electrode sheet, the median R A50 of roughness is 0.92 to 0.96.
  14. 14. The lithium ion secondary battery according to claim 1, wherein in the cumulative distribution curve of the area of the sphericity of the particles obtained by the section of the positive electrode film layer in the thickness direction of the electrode sheet, L A90 of sphericity is 0.80-0.95.
  15. 15. The lithium ion secondary battery according to claim 14, wherein in the cumulative distribution curve of the area of the sphericity of the particles obtained by the section of the positive electrode film layer in the thickness direction of the electrode sheet, L A90 of sphericity is 0.85-0.93.
  16. 16. The lithium ion secondary battery according to claim 1, wherein in the cumulative distribution curve of the area of the sphericity of the particles obtained by the section of the positive electrode film layer in the thickness direction of the electrode sheet, the median L A50 of the sphericity is 0.65-0.85.
  17. 17. The lithium ion secondary battery according to claim 16, wherein in the cumulative distribution curve of the area of the sphericity of the particles obtained by the section of the positive electrode film layer in the thickness direction of the electrode sheet, the median L A50 of the sphericity is 0.70 to 0.80.
  18. 18. The lithium ion secondary battery according to claim 1, wherein the positive electrode active material includes an iron element, and the positive electrode film layer has an iron dissolution rate of 500ppm to 2000ppm.
  19. 19. The lithium ion secondary battery according to claim 18, wherein the iron dissolution rate of the positive electrode film layer is 500ppm to 1500ppm.
  20. 20. The lithium ion secondary battery according to claim 1, wherein the mass content of the carbon element is 0.8% to 1.8% based on the total mass of the positive electrode active material.

Description

Lithium ion secondary battery, battery device, and electricity using device The application is a divisional application of an application patent application with the application number of 202510512090.0, namely a lithium ion secondary battery, a battery device and an electric device, wherein the application number is 2025, 04 and 23. Cross reference The application is incorporated into the present application by reference to PCT International application No. PCT/CN2025/085940 entitled "lithium ion Secondary Battery, battery device, electric device, method for producing Positive electrode active Material and method for producing Positive electrode sheet," filed on 28 days 3 of 2025. Technical Field The application relates to the technical field of lithium ion batteries, in particular to a lithium ion secondary battery, a battery device, an electric device, a preparation method of an anode active material and a preparation method of an anode plate. Background In recent years, secondary batteries are widely used in energy storage power supply systems such as hydraulic power, thermal power, 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. The positive electrode active material is an important component of the lithium ion secondary battery, and the lithium-containing transition metal phosphate material has the characteristics of stable structure, good safety and long cycle life, and has wide development prospect. With the improvement of energy density and dynamics requirements of secondary batteries of lithium-containing transition metal phosphate systems in the market, the improvement of the performances is difficult to achieve simultaneously in the prior art, and the improvement is a technical problem to be solved in the field. Disclosure of Invention The present application has been made in view of the above problems, and an object thereof is to provide a lithium ion secondary battery having both high energy density and good dynamic performance. The first aspect of the application provides a lithium ion secondary battery, which comprises a positive electrode plate, a negative electrode plate and an electrolyte, 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 positive electrode film layer comprises a positive electrode active material, at least part of the positive electrode active material comprises lithium-containing transition metal phosphate particles with carbon coating materials arranged on the surface, the positive electrode film layer is subjected to graphitization degree C value accumulation distribution curve obtained in a laser micro-confocal Raman spectrometer surface scanning mode, the graphitization degree median C 50 is more than or equal to 0.95 and less than or equal to 1.20, the C value concentration (C 90-C10)/C50 is 0.01-0.04), wherein the graphitization degree C value is I G/ID,IG and represents the G peak intensity of a Raman spectrum at 1580+/-100 cm -1, and I381350 represents the D peak intensity of the Raman spectrum at +/-100 cm -1. According to the embodiment of the application, the median C 50 of the graphitization degree is more than or equal to 0.95 and less than or equal to 1.20, and the concentration degree of C value is controlled (C 90-C10)/C50 is 0.01-0.04, which shows that the graphitization degree of particles in the positive electrode film layer is high and the graphitization consistency degree is high, meaning that the positive electrode active material has good coating uniformity and consistency, the defect that the particles slide and further cause local stress concentration caused by low graphitization degree of the particles in the positive electrode active material can be reduced, so that the pole piece can realize higher compaction density integrally under relatively low rolling pressure through uniform sliding among the particles of the positive electrode active material, and meanwhile, the uniform graphitization degree is favorable for realizing uniform embedding and extraction of lithium ions, and the energy density of the pole piece and the battery are improved on the basis of keeping good dynamic performance of the battery. The median C 50 of the graphitization degree of the positive electrode film layer is in the range, so that the easy slip degree among particles is further improved, the compaction density of the pole piece is further improved while the high dynamic performance of the battery is maintained, and the dynamic performance and the energy density of the battery are both realized. In any embodiment, the concentration of C value (C 90-C10)/C50 is 0.02-0.038, optionally 0.02-0.036) in the cumulative distribution curve of C value of graphitization degree obtained