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CN-224217465-U - Electrode plate of lithium ion battery and lithium ion battery

CN224217465UCN 224217465 UCN224217465 UCN 224217465UCN-224217465-U

Abstract

The utility model provides a lithium ion battery electrode plate which comprises a current collector and an active material layer, wherein the active material layer comprises active material particles, porous nanofibers are distributed among the active material particles, the active material layer comprises n sub-layers, n is more than or equal to 2 and less than or equal to 10, the diameters of the porous nanofibers in the n sub-layers are sequentially reduced and/or the mass content of the porous nanofibers in the n sub-layers is sequentially reduced from the surface layer of the plate to the current collector, and the thickness of the active material layer is 40-100 mu m. The electrode pole piece has more excellent liquid absorption and retention performance, increases an electrolyte rapid diffusion channel, can greatly improve the wettability of a thick electrode, improves the ionic conductivity of the pole piece, reduces the concentration polarization in the thickness direction of the pole piece, and improves the problems of the SOC difference in the thickness direction of the pole piece, the low capacity, the rate difference and the circulation difference of the thick electrode.

Inventors

  • ZHANG LEI
  • ZHAO JIAXING
  • LI WEI
  • LIU ZHIMIN

Assignees

  • 北京车和家汽车科技有限公司

Dates

Publication Date
20260508
Application Date
20250328

Claims (10)

  1. 1. The electrode plate of the lithium ion battery is characterized by comprising a current collector and an active material layer; The active material layer comprises active material particles, porous nano fibers are distributed among the active material particles, The active material layer comprises n sub-layers, n is more than or equal to 2 and less than or equal to 10, and the diameters of the porous nanofibers in the n sub-layers are sequentially reduced and/or the mass content of the porous nanofibers in the n sub-layers is sequentially reduced from the surface layer of the pole piece to the current collector; The thickness of the active material layer is 40-100 mu m.
  2. 2. The lithium ion battery electrode pole piece according to claim 1, wherein n is more than or equal to 2 and less than or equal to 4; The mass content of the porous nanofiber in the active material layer is 0.05-0.3%; The diameter of the porous nanofiber is 5-500 nm, the length of the porous nanofiber is 3-50 mu m, and the porosity of the porous nanofiber is 50-90%.
  3. 3. The electrode pole piece of lithium ion battery according to claim 1, wherein from the pole piece surface layer to the current collector, when the diameters of the porous nanofibers in the n sub-layers are sequentially reduced, the mass content of the porous nanofibers in the n sub-layers is the same or sequentially reduced; When the mass content of the porous nanofibers in the n sub-layers is sequentially reduced, the diameters of the porous nanofibers in the n sub-layers are the same or sequentially reduced.
  4. 4. The electrode tab of claim 1, wherein the porous nanofibers in the first layer of the active material layer have a diameter of 200-500 nm when n=2, The diameter of the porous nanofiber in the second layer in the active material layer is 5-350 nm.
  5. 5. The lithium ion battery electrode sheet according to claim 1, wherein when n=3, the diameter of the porous nanofiber in the first layer in the active material layer is 300 to 500nm; the diameter of the porous nanofiber in the second layer in the active material layer is 200-400 nm; The diameter of the porous nanofiber in the third layer in the active material layer is 5-300 nm.
  6. 6. The lithium ion battery electrode sheet according to claim 1, wherein when n=2, the mass content of the porous nanofibers in the first layer of the active material layers is 0.15 to 0.3%, The mass content of the porous nano fiber in the second layer in the active material layer is 0.05-0.2%.
  7. 7. The lithium ion battery electrode slice according to claim 1, wherein when n=3, the mass content of the porous nanofiber in the first layer in the active material layer is 0.15-0.3%; The mass content of the porous nano fiber in the second layer in the active material layer is 0.1-0.2%; the mass content of the porous nano fiber in the third layer in the active material layer is 0.05-0.15%.
  8. 8. The lithium ion battery electrode slice according to claim 1, wherein when n=4, the mass content of the first layer of porous nanofibers in the active material layer is 0.2-0.3%; the mass content of the porous nano fiber in the second layer in the active material layer is 0.15-0.25%; The mass content of the porous nano fiber in the third layer in the active material layer is 0.08-0.18%; And the mass content of the porous nano fiber in the fourth layer in the active material layer is 0.05-0.1%.
  9. 9. The lithium ion battery electrode sheet according to claim 1, wherein when n=2, the thickness of the first layer in the active material layer is 20 to 30 μm, and the thickness of the second layer is 20 to 30 μm; When n=3, the thickness of the first layer in the active material layer is 25-40 μm, the thickness of the second layer is 25-40 μm, and the thickness of the third layer is 25-40 μm; When n=4, the thickness of the first layer in the active material layer is 30-50 μm, the thickness of the second layer is 30-50 μm, the thickness of the third layer is 30-50 μm, and the thickness of the fourth layer is 30-50 μm.
  10. 10. A lithium ion battery comprising the lithium ion electrode sheet of any one of claims 1-9.

Description

Electrode plate of lithium ion battery and lithium ion battery Technical Field The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery electrode plate and a lithium ion battery. Background During operation of the lithium ion battery, the electrolyte can permeate into the electrode material to react with the active substances therein to release electrons. The better the wettability of the electrode material to the electrolyte, the more effectively the electrode material can be contacted with the electrolyte, thereby improving the performance of the battery. The electrode material with good wettability can be contacted with ions in electrolyte more quickly, so that the charge transmission efficiency is improved, and the energy density and the charging speed of the battery are improved. And the electrode material with poor wettability can lead electrolyte to be unable to effectively permeate in, so that the charge transmission speed is limited, and the performance of the battery is reduced. Therefore, the wettability of the electrode plate is an important performance index, and has important influence on the capacity, the cycle life and the charging speed of the battery. When the thickness of the pole piece of the lithium ion battery is larger, the tortuosity of the pole piece is larger, the active material close to the foil side is very difficult to infiltrate, the infiltration state is poorer, the liquid phase diffusion path of the pole piece lithium ions is longer in the charging and discharging process, and larger concentration polarization exists in the thickness direction of the pole piece, so that the capacity is insufficient, the multiplying power performance is poorer and the cycle life is accelerated and attenuated. Disclosure of utility model The utility model aims to provide a lithium ion battery electrode pole piece and a lithium ion battery, wherein the lithium ion battery electrode pole piece has more excellent liquid absorption and retention performances, can increase an electrolyte rapid diffusion channel, can greatly improve the wettability of a thick electrode (with the thickness of more than 50 mu m), improves the ion conductivity of the pole piece, reduces the concentration polarization in the thickness direction of the pole piece, and improves the SOC difference in the thickness direction of the pole piece and the problems of low capacity, rate difference and circulation difference of the thick electrode. The utility model provides a lithium ion battery electrode slice, which comprises a current collector and an active material layer; The active material layer comprises active material particles, porous nano fibers are distributed among the active material particles, The active material layer comprises n sub-layers, n is more than or equal to 2 and less than or equal to 10, and the diameters of the porous nanofibers in the n sub-layers are sequentially reduced and/or the mass content of the porous nanofibers in the n sub-layers is sequentially reduced from the surface layer of the pole piece to the current collector; The thickness of the active material layer is 40-100 mu m. The utility model provides a lithium ion battery, which comprises the lithium ion electrode pole piece. The utility model provides a lithium ion battery electrode plate which comprises a current collector and an active material layer, wherein the active material layer comprises active material particles, porous nanofibers are distributed among the active material particles, the active material layer comprises n sub-layers, n is more than or equal to 2 and less than or equal to 10, the diameters of the porous nanofibers in the n sub-layers are sequentially reduced and/or the mass content of the porous nanofibers in the n sub-layers is sequentially reduced from the surface layer of the plate to the current collector, and the thickness of the active material layer is 40-100 mu m. Aiming at a thicker pole piece with the thickness of more than 50 mu m, the porous nanofiber is added in the pole piece, and the multi-layer structure of the porous nanofiber with the content gradient and/or the diameter gradient is arranged in the thickness direction of the pole piece according to the ion diffusion rule, so that the pole piece has more excellent liquid absorption and liquid retention performances, a rapid electrolyte diffusion channel is increased, the wettability of a thick electrode can be greatly improved, the ion conductivity of the pole piece is improved, the concentration polarization in the thickness direction of the pole piece is reduced, and the problems of SOC difference in the thickness direction of the pole piece and low capacity, rate difference and circulation difference of the thick electrode are improved. Furthermore, the porous nanofiber has good flexibility, so that brittleness of a thick electrode negative electrode plate can be improved, th