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CN-122000300-A - Pole piece of lithium ion battery and preparation method thereof

CN122000300ACN 122000300 ACN122000300 ACN 122000300ACN-122000300-A

Abstract

The invention provides a pole piece of a lithium ion battery and a preparation method thereof, wherein the pole piece of the lithium ion battery comprises a current collector and an active material coated on the current collector, the active material and an adhesive are arranged, so that the active material can be conveniently and quickly fixed when extruded and arranged on the current collector along an angle, the assembly state of the active material on the current collector is stabilized, the active material is arranged in a slit die cavity to be extruded, the active material moves and deforms towards a single side direction, the structure becomes long and narrow, the end part of the active material with the long and narrow structure is connected with the current collector for rolling, the tortuosity of the pole piece of the lithium ion battery is reduced, the migration rate of lithium ions in the pole piece and the embedding rate of the lithium ions in the active material are accelerated, meanwhile, the problem that the expansion of the pole piece in the thickness direction of the pole piece is increased due to the lithium ion embedding is reduced, and the probability of the deformation of the lithium ion battery is reduced.

Inventors

  • ZHANG SHUANGHU
  • WANG LONG
  • FANG HAIGUO
  • XU XI

Assignees

  • 福州杰瑞动能科技有限公司

Dates

Publication Date
20260508
Application Date
20241108

Claims (10)

  1. 1. A pole piece of a lithium ion battery, which is characterized by comprising a current collector and an active material coated on the current collector: The active material comprises, by mass, 95-98% of active material, 0-3% of conductive agent and 0.5-2% of adhesive.
  2. 2. The pole piece of a lithium ion battery of claim 1, wherein the active material is in the form of graphite flakes or graphene flakes.
  3. 3. The pole piece of lithium ion battery of claim 1, wherein the current collector is copper foil, nickel foam, copper foam, a metal polymer composite current collector, graphene or graphite paper.
  4. 4. The pole piece of the lithium ion battery according to claim 1, wherein the active material comprises the following components in percentage by mass of 98% of active material, 1% of conductive agent and 1% of adhesive.
  5. 5. The pole piece of the lithium ion battery according to claim 1, wherein the active material comprises the following components in percentage by mass of 95% of active material, 3% of conductive agent and 2% of adhesive.
  6. 6. The pole piece of the lithium ion battery according to claim 1, wherein the active material comprises 97% of active material, 2% of conductive agent and 1% of adhesive by mass.
  7. 7. A method for preparing a pole piece of a lithium ion battery, which is characterized in that the pole piece of the lithium ion battery is a pole piece of the lithium ion battery as claimed in any one of claims 1 to 6, comprising the following steps: s101, mixing a conductive agent, an adhesive and an active material required by the active material; s102, placing an active material into a slit die cavity; s103, extruding the slit die cavity until the active material is extruded to be perpendicular to the motion direction of the extrusion process; S104, opening a slit die cavity, transferring the extruded active material to a current collector, and forming an included angle with the current collector; s105, drying the current collector and the active material; And S106, rolling the active material and the current collector, and rolling and pulling the active material to prepare and form a pole piece with the active material arranged in the vertical direction on the current collector.
  8. 8. The method of manufacturing a lithium ion battery according to claim 7, wherein in the step of drying the current collector and the active material, the drying temperature is in the range of 100 to 140 ℃ for 0.5 to 3 minutes.
  9. 9. The method for preparing a lithium ion battery pole piece according to claim 7, wherein the included angle between the active material and the current collector is 30-90 °.
  10. 10. The method of manufacturing a lithium ion battery according to claim 7, wherein in the step of pressing the slit die cavity until the active material stops in a direction perpendicular to the movement direction of the pressing process, the pressing pressure is 0.2Mpa to 30Mpa.

Description

Pole piece of lithium ion battery and preparation method thereof Technical Field The invention relates to the technical field of pole pieces of lithium ion batteries, in particular to a pole piece of a lithium ion battery and a preparation method thereof. Background Lithium ion batteries are ideal energy storage devices and are widely applied to the fields of electronic products, electric automobiles, electric tools and the like. In addition, in the use process of the lithium ion battery, lithium ions are embedded in the end face of a graphite material in the charging process, so that the spacing between graphite layers is increased, the pole pieces expand, the expansion rate of the pole pieces in the direction perpendicular to the current collector is larger than that in the direction parallel to the pole pieces, and the expansion rate of the battery is gradually increased along with the circulation, so that the battery is deformed and an electric device is damaged. The existing common active material orientation technology comprises a method of adding an external magnetic field of magnetic particles, an ice template method, an external magnetic field method and the like. The method is complicated in process, and the actual orientation effect is poor after the pole piece subjected to orientation is dried by a solvent and rolled. Disclosure of Invention In view of the above problems, the present invention aims to provide a pole piece of a lithium ion battery and a preparation method thereof, so as to solve the problem that in the prior art, the expansion rate of the pole piece in the direction perpendicular to a current collector is larger than that in the direction parallel to the pole piece, and the expansion rate of the battery is gradually increased, so that the battery is deformed, and an electrical device is damaged. In order to solve the above problems, the present inventors provide a pole piece of a lithium ion battery, including a current collector, and an active material composition coated on the current collector: The active material comprises, by mass, 95-98% of active material, 0-3% of conductive agent and 0.5-2% of adhesive. Compared with the prior art, the technical scheme has the advantages that the active material and the adhesive are arranged, so that the active material can be conveniently and quickly fixed when being extruded and arranged on the current collector along an angle, and the assembly state of the active material on the current collector is stabilized. As a preferred embodiment of the present application, the active material is in the form of graphite flakes or graphene flakes. The active material is conveniently processed by arranging the active material in the shape of flake graphite or flake graphene. As a preferred embodiment of the present application, the current collector is copper foil, nickel foam, copper foam or graphite paper. The copper foil, the foam nickel, the foam copper and the metal polymer composite current collector or the graphite paper are adopted as the current collector, so that the pole piece can be conveniently operated. As a preferred embodiment of the application, the active material comprises the following components in percentage by mass of 98% of active material, 1% of conductive agent and 1% of adhesive. As a preferred embodiment of the application, the active material comprises the following components in percentage by mass of 95% of active material, 3% of conductive agent and 2% of adhesive. As a preferred embodiment of the application, the active material comprises the following components in percentage by mass of 97% of active material, 2% of conductive agent and 1% of adhesive. In order to achieve the above object, the present inventors also provide a method for preparing a pole piece of a lithium ion battery, where the pole piece of the lithium ion battery is a pole piece of the lithium ion battery described in the above embodiment, including the following steps: s101, mixing a conductive agent, an adhesive and an active material required by the active material; s102, placing an active material into a slit die cavity; s103, extruding the slit die cavity until the active material is extruded to be perpendicular to the motion direction of the extrusion process; S104, opening a slit die cavity, transferring the extruded active material to a current collector, and forming an included angle with the current collector; s105, drying the current collector and the active material; And S106, rolling the active material and the current collector, and rolling and pulling the active material to prepare and form a pole piece with the active material arranged in the vertical direction on the current collector. Compared with the prior art, the technical scheme has the advantages that the active material is placed into the slit die cavity for extrusion, the active material moves to deform in the single-side direction, so that the structure becomes long and