Search

CN-122000424-A - Battery monomer, battery device and power utilization device

CN122000424ACN 122000424 ACN122000424 ACN 122000424ACN-122000424-A

Abstract

The application relates to the technical field of batteries, and provides a battery unit, a battery device and an electric device, wherein the battery unit comprises electrolyte and an electrode assembly, the electrode assembly comprises an anode plate and a cathode plate, the cathode plate comprises a cathode current collector and a cathode active material layer arranged on at least one side of the cathode current collector, the cathode active material layer comprises carbon-coated graphite, amorphous carbon is arranged on the surface of the carbon-coated graphite, the electrolyte comprises a solvent, the solvent comprises linear carboxylate, the size of the cathode active material layer is larger than 130mm along a first direction, and the first direction is parallel to the gravity direction. According to the application, carbon-coated graphite is used as a negative electrode active material, and is matched with the electrolyte containing the linear carboxylate, so that the problems of local aggregation and low heat dissipation efficiency of the electrolyte in a high battery cell can be effectively solved, and the cycle life of a battery cell can be further prolonged.

Inventors

  • HUANG YUTONG

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20251029

Claims (20)

  1. 1. A battery cell is characterized by comprising an electrode assembly and electrolyte; The electrode assembly comprises a positive electrode plate and a negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer arranged on at least one side of the negative electrode current collector, the negative electrode active material layer comprises carbon-coated graphite, and amorphous carbon is arranged on the surface of the carbon-coated graphite; the electrolyte includes a solvent including a linear carboxylate; The size of the anode active material layer is greater than 130mm along a first direction, which is parallel to the direction of gravity.
  2. 2. The battery cell of claim 1, wherein the anode active material layer comprises a first anode active material layer and a second anode active material layer disposed in a thickness direction of the anode current collector with the first anode active material layer disposed between the anode current collector and the second anode active material layer, wherein the first anode active material layer comprises a first graphite and the second anode active material layer comprises a second graphite, wherein the second graphite comprises the carbon-coated graphite, and wherein the first graphite has a graphitization degree of 94% to 98%.
  3. 3. The battery cell of claim 2, wherein the first graphite has a Dv50 particle size that is greater than a Dv50 particle size of the second graphite.
  4. 4. The battery cell of claim 2 or claim 3, wherein the gram capacity of the first graphite is greater than or equal to the gram capacity of the second graphite.
  5. 5. The battery cell of any one of claims 2 to 4, wherein the first graphite satisfies at least one of the following features (1) - (3): (1) The Dv50 particle size of the first graphite is 14.0-18.5 mu m; (2) The gram capacity of the first graphite is 358mAh/g-368mAh/g; (3) The first graphite comprises one or more of primary particles and secondary particles.
  6. 6. The battery cell of any one of claims 2 to 5, wherein the second graphite satisfies at least one of the following features (1) - (4): (1) The Dv50 particle size of the second graphite is 9.8-13.8 mu m; (2) The graphitization degree of the second graphite is 90% -93%; (3) The gram capacity of the second graphite is 350mAh/g-358mAh/g; (4) The OI value of the second graphite is 3.6-4.1, the OI value of the second graphite=C004/C110, C004 is the peak area of the diffraction peak of the crystal face of the second graphite 004, and C110 is the peak area of the diffraction peak of the crystal face of the second graphite 110.
  7. 7. The battery cell according to any one of claims 2 to 6, wherein a thickness ratio of the second anode active material layer to the first anode active material layer is (7:3) to (5:5).
  8. 8. The battery cell of any one of claims 1 to 7, wherein the negative electrode tab satisfies at least one of the following features (1) - (3): (1) The single-sided coating weight of the anode active material layer is 130mg/1540mm 2 ~160mg/1540mm 2 ; (2) The thickness of the negative electrode plate is 0.115mm-0.125mm; (3) The compacted density of the negative electrode plate is 1.6 g/cm 3 -1.78g/cm 3 .
  9. 9. The battery cell according to any one of claims 1 to 8, wherein the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer provided on at least one side of the positive electrode current collector, the positive electrode sheet satisfying at least one of the following features (1) to (3): (1) The single-sided coating weight of the positive electrode active material layer is 310mg/1540mm 2 ~350mg/1540mm 2 ; (2) The thickness of the positive pole piece is 0.17mm-0.18mm; (3) The compacted density of the positive electrode plate is 2.6 g/cm 3 -2.8 g/cm 3 .
  10. 10. The battery cell of any one of claims 1 to 9, wherein the solvent further comprises a cyclic carbonate, the mass ratio of the linear carboxylate to the cyclic carbonate being (6-7): 3-4.
  11. 11. The battery cell of any one of claims 1 to 9, wherein the solvent further comprises a linear carbonate and a cyclic carbonate, the mass ratio of the linear carboxylate, the linear carbonate, and the cyclic carbonate being (2-4): 3-4.
  12. 12. The battery cell of any one of claims 1 to 11, wherein the electrolyte has a conductivity of 9mS/cm to 18.5mS/cm.
  13. 13. The battery cell of claim 12, wherein the electrolyte has a conductivity of 14mS/cm to 18.5mS/cm.
  14. 14. The battery cell of any one of claims 1 to 13, wherein the electrolyte has a viscosity of 0.5mm 2 /s-4mm 2 /s at 25 ℃.
  15. 15. The battery cell of any one of claims 1 to 14, wherein the electrolyte further comprises a lithium salt comprising at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis (oxalato) borate, lithium bis (trifluoromethylsulfonyl) imide, lithium perchlorate, lithium hexafluoroarsenate.
  16. 16. The battery cell of any one of claims 1-15, wherein the battery cell has a fill factor of 2.7g/Ah to 3.2 g/Ah.
  17. 17. The battery cell of any one of claims 1 to 16, further comprising an additive in the electrolyte, wherein the additive comprises vinylene carbonate and/or the additive is present in the electrolyte at a mass concentration of 1% -2%.
  18. 18. The battery cell according to any one of claims 1 to 17, wherein the anode active material layer includes a first conductive agent including a zero-dimensional conductive agent and a multi-dimensional conductive agent including at least one of a one-dimensional conductive agent and a two-dimensional conductive agent.
  19. 19. The battery cell of claim 18, wherein the zero-dimensional conductive agent comprises at least one of conductive carbon black, ketjen black, acetylene black, and/or, The one-dimensional conductive agent comprises at least one of carbon nano tubes and carbon nano fibers, and the carbon nano tubes comprise at least one of multi-wall carbon nano tubes, single-wall carbon nano tubes and few-wall nano tubes, and/or, The two-dimensional conductive agent comprises at least one of layered conductive graphite and graphene.
  20. 20. The battery cell of claim 18 or 19, wherein the mass ratio of the zero-dimensional conductive agent to the multi-dimensional conductive agent is 4:1 to 1:4.

Description

Battery monomer, battery device and power utilization device Technical Field The application belongs to the technical field of batteries, and particularly relates to a battery cell, a battery device and an electricity utilization device. Background The lithium ion battery has the characteristics of high energy density, long cycle life, environmental protection and the like, is widely applied to energy storage power supply systems of hydraulic power, firepower, wind power, solar power stations and the like, and has wide application in a plurality of fields of electric tools, electric bicycles, electric motorcycles, electric automobiles, aerospace and the like. Along with the continuous improvement of the energy supplementing efficiency requirement of the electric device in the market, higher requirements are also put forward on the cycle performance of the battery monomer. The statements made above merely serve to provide background information related to the present disclosure and may not necessarily constitute prior art. Disclosure of Invention The application aims to provide a battery cell, a battery device and an electricity utilization device, which aim to improve the cycle performance of the battery cell. In order to achieve the purposes of the application, the technical scheme adopted by the application is as follows: In a first aspect, the present application provides a battery cell. The battery monomer comprises electrolyte and an electrode assembly, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer arranged on at least one side of the negative electrode current collector, the negative electrode active material layer comprises carbon-coated graphite, and amorphous carbon is arranged on the surface of the carbon-coated graphite; The electrolyte comprises a solvent, and the solvent comprises linear carboxylic ester; the size of the anode active material layer is greater than 130mm along a first direction, which is parallel to the direction of gravity. According to the technical scheme, the high-power cell can improve energy density, carbon-coated graphite is used as a negative electrode active material, and the electrolyte containing linear carboxylate is matched, so that the problems of local aggregation and low heat dissipation efficiency of the electrolyte in the high-power cell can be effectively solved, and the cycle life of a battery monomer is further prolonged. The amorphous carbon-containing graphite has excellent adsorption capacity to electrolyte, can effectively lock the electrolyte, strengthen the holding effect to the electrolyte, relieve the tendency of the electrolyte to gather to the lower part of a high cell under the action of gravity, further improve the electrolyte infiltration state of an upper electrode, reduce the reaction difference caused by partial infiltration shortage, enable the current distribution to be more balanced, the surface amorphous carbon of the carbon-containing graphite can remarkably improve the electronic conductivity of the carbon-containing graphite, greatly reduce the ion diffusion resistance by optimizing the diffusion path of lithium ions in a negative electrode, enable the lithium ions to be more uniformly distributed in a battery system, effectively relieve the problem of lithium ion concentration gradient caused by long transmission path of the high cell, and meanwhile, the electrolyte adopts linear carboxylate as a solvent, thereby being beneficial to reducing the viscosity of the electrolyte, remarkably improving the infiltration and reflux capacity of the electrolyte in the high cell, enhancing the electrolyte climbing capacity in the high cell, improving the uniform distribution of the electrolyte in the high cell, further optimizing the ion transmission environment in the high cell, effectively reducing the final cycle life of the electrolyte gathered to the final cell. In some embodiments, the anode active material layer includes a first anode active material layer and a second anode active material layer disposed along a thickness direction of the anode current collector, and the first anode active material layer is disposed between the anode current collector and the second anode active material layer, the first anode active material layer includes a first graphite, the second anode active material layer includes a second graphite, the second graphite includes carbon-coated graphite, and the graphitization degree of the first graphite is 94% -98%. The negative electrode plate provided by the embodiment of the application adopts a double-layer coating design, and the negative electrode active material layer is subjected to differential design, so that the side reaction between the carbon-coated graphite and the linear carboxylate can be effectively relieved, and the battery monomer has better quick charge capability and higher energy density. In some embodiments