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CN-121983516-A - Pole piece and preparation method thereof

CN121983516ACN 121983516 ACN121983516 ACN 121983516ACN-121983516-A

Abstract

The application discloses a pole piece and a preparation method thereof, and relates to the technical field of lithium ion batteries. The method comprises the following steps of 1, coating conductive slurry on the surface of a current collector, drying to form an active material layer, rolling to obtain a pole piece A, and 2, carrying out groove processing on the surface of the pole piece A to form a groove to obtain the pole piece. The pole piece prepared by the specific process can be applied to a lithium ion battery, and the surface of the pole piece is designed with a specific groove structure, so that the infiltration of condensed electrolyte is effectively improved, the infiltration time is shortened, and the interface impedance of the battery is reduced.

Inventors

  • ZHOU KAI
  • LIU KE
  • LI XUEFA

Assignees

  • 扬州纳力新材料科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (10)

  1. 1. The pole piece is characterized by comprising an active material layer, wherein grooves are formed in the surface of the active material layer, the width of each groove is 0.02-0.1 mm, the depth of each groove is 2-15 mu m, and the distance between the grooves is 100-450 mu m.
  2. 2. The method for preparing the pole piece according to claim 1, which is characterized by comprising the following steps: step 1, coating conductive slurry on the surface of a current collector, drying to form an active material layer, and rolling to obtain a pole piece A; And 2, carrying out groove processing on the surface of the pole piece A to form a groove, thereby obtaining the pole piece.
  3. 3. The method for preparing the pole piece according to claim 2, wherein the groove processing comprises laser etching, and the technological parameters of the laser etching are that the laser power is 30-150W and the scanning speed is 5-30 m/min.
  4. 4. The method for preparing the pole piece according to claim 3, wherein the post-treatment is performed after the laser etching, the process parameters of the post-treatment are that the pressure of the negative pressure fine powder is-1.0 to-0.05 MPa, the drying temperature is 80-150 ℃, and the drying time is 1-5 h.
  5. 5. The method for manufacturing a pole piece according to claim 2, wherein the thickness of the active material layer is 70-350 μm, and the compacted density of the active material layer after rolling is 1.5-4.2 g/cm 3 .
  6. 6. The method for preparing the pole piece according to claim 2, wherein the solid content of the conductive paste is 35-75wt% and the solvent is deionized water; The raw materials of the conductive paste comprise (85-95)/(2-7)/(3-8) active materials, a binder and carbon black in mass ratio.
  7. 7. The method of claim 6, wherein the active material comprises graphite and the binder comprises one or both of styrene-butadiene rubber binder and polyacrylic acid type binder.
  8. 8. The method for preparing a pole piece according to claim 7, wherein the method for preparing the polyacrylic acid type binder is as follows: Step 1, adding 1, 6-dibromopyrene, 4-vinylphenylboronic acid, potassium carbonate and tetraphenylphosphine palladium into an N, N-dimethylformamide aqueous solution under the argon atmosphere, reacting for 20-28 h at 85-95 ℃, cooling, purifying and drying to obtain vinyl-terminated pyrene; Adding allyloxy hydroxypropyl sodium sulfonate, primary ammonium persulfate and mercapto polyethylene glycol dopamine into deionized water, stirring at 70-80 ℃, adding a mixed monomer consisting of methyl methacrylate, butyl acrylate, methacrylic acid, vinyl end-capped pyrene and N-vinylcarbazole, adding secondary ammonium persulfate, reacting at 75-85 ℃ for 3-4 hours, cooling, and adding ammonia water to adjust the pH to 7.4-7.6 to obtain the polyacrylic acid type adhesive.
  9. 9. The method for preparing the pole piece according to claim 8, wherein the mass ratio of 1, 6-dibromopyrene, 4-vinylphenylboric acid, potassium carbonate and tetraphenylphosphine palladium in the vinyl-terminated pyrene is (1.2-1.5): 1.1-1.5): 0.8-1): 0.1-0.3; In the mixed monomer, the mass ratio of methyl methacrylate, butyl acrylate, methacrylic acid, vinyl end-capped pyrene and N-vinyl carbazole is (2.6-3.5): (7.3-8.3): (0.5-0.7): (5-6): 1; The raw materials of the polyacrylic acid type adhesive comprise, by mass, 100 parts of mixed monomers, 3-6 parts of allyloxy hydroxypropyl sodium sulfonate, 1-2 parts of primary ammonium persulfate, 0.5-3 parts of sulfhydryl polyethylene glycol dopamine, 1-3 parts of secondary ammonium persulfate and 150-220 parts of deionized water.
  10. 10. The method for preparing a pole piece according to claim 9, wherein the molecular weight of the sulfhydryl polyethylene glycol dopamine is 1000.

Description

Pole piece and preparation method thereof Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a pole piece and a preparation method thereof. Background The lithium ion battery is widely applied to the fields of power and energy storage because of the advantages of higher energy density, good cycle life and the like. The condensed electrolyte adopted by the solid-state battery is nonflammable and non-leaky, and meanwhile, has extremely strong thermal stability, thereby being beneficial to preventing the dangers such as liquid leakage, combustion explosion and the like. Therefore, solid-state batteries have become a hot research topic today. However, with the intensive research, it has been found that, compared with the conventional liquid electrolyte, the condensed electrolyte of the solid-state battery is mostly in a viscous state, and the problems of uneven infiltration, poor interface contact and the like often occur in the liquid injection process. At present, a process of curing after injecting a gel precursor into a battery is generally adopted in the industry. However, due to the problems of high viscosity, poor fluidity and the like of the gel electrolyte, the gel electrolyte is difficult to fully infiltrate into the pole piece by virtue of capillary action, the normal-temperature standing infiltration time is long (12-96 h), and even if the gel electrolyte is assisted by measures such as heating, pressurizing and the like, the gel electrolyte still needs 12-48 h to completely form a stable gel layer, so that the production rhythm is greatly slowed down. In addition, the surface energy of substances such as pole piece surface active materials, adhesives and the like is large in difference, electrolyte is easy to locally gather, an incomplete immersed dry area is formed, and the consistency of the performance of the battery cell is affected. In summary, the preparation of a pole piece for improving the wettability of the solid-state battery condensed electrolyte has important significance in solving the problems. Disclosure of Invention The invention aims to provide a pole piece and a preparation method thereof, which are used for solving the problems in the background technology. In order to solve the technical problems, the invention provides the following technical scheme: The pole piece comprises an active material layer, grooves are formed in the surface of the active material layer, the width of each groove is 0.02-0.1 mm, the depth of each groove is 2-15 mu m, and the distance between the grooves is 100-450 mu m. The patterns of the grooves are transverse straight lines, so that the electrolyte can be filled rapidly and form a stable transmission channel, the occupation of excessive active material space is avoided, and the radiation diffusion of the electrolyte to the inside of the pole piece can be ensured. The total volume of the groove structure is controlled to be 5% -10% of the pore volume of the active material layer, so that the infiltration effect is not affected due to the fact that the volume is too small, and the capacity loss of the pole piece is not caused due to the fact that the volume is too large. The preparation method of the pole piece comprises the following steps: step 1, coating conductive slurry on the surface of a current collector, drying to form an active material layer, and rolling to obtain a pole piece A; And 2, carrying out groove processing on the surface of the pole piece A to form a groove, thereby obtaining the pole piece. In a further scheme, the structure of the grooves adopts a grid-shaped design of combining a main channel and a branch channel, the main channel continuously extends along the TD direction of the pole piece and is used as a main channel for rapidly spreading electrolyte, and the electrolyte is guided to each area of the pole piece to realize uniform infiltration. More preferably, the groove processing comprises laser etching, wherein the technological parameters of the laser etching are that the laser power is 30-150W, and the scanning speed is 5-30 m/min. In a further scheme, the formation of the groove by laser etching (scribing) is a key link. The method is suitable for the pole pieces of brittle materials such as high-nickel ternary materials, silicon-based materials and the like, has small thermal influence, can accurately control the size of the groove, and realizes batch production. After processing, dust in the groove is removed through negative pressure powder suction, so that electrolyte pollution is avoided, the whole process is performed in a high dew point drying room, the moisture content of the pole piece is controlled below 100ppm, and the influence on stability of sensitive electrolyte such as sulfide is avoided. More optimally, the post-treatment is carried out after the laser etching, wherein the process parameters of the post-treatment are that the pressure of the negati