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CN-121983581-A - Current collector and preparation method and application thereof

CN121983581ACN 121983581 ACN121983581 ACN 121983581ACN-121983581-A

Abstract

The invention discloses a current collector and a preparation method and application thereof. The current collector comprises a high polymer layer, a metal layer and an adhesive transition layer positioned between the high polymer layer and the metal layer, wherein the adhesive transition layer comprises a functional polymer, and the functional polymer is a copolymer containing a polar group and a flexible chain segment. According to the current collector, the special adhesive transition layer is arranged at the interface between the metal layer and the high polymer layer, the adhesive transition layer contains the functional polymer with a specific structure and composition, and the internal friction and chain segment movement of the polymer molecular chain are utilized to efficiently dissipate the interface stress energy, so that the internal stress generated by the expansion and contraction difference of the metal and the high polymer material is obviously reduced, the interface damage is effectively avoided, and the structural stability of the current collector is greatly improved.

Inventors

  • CAO YUNHU
  • LI XUEFA

Assignees

  • 江阴纳力新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20260202

Claims (10)

  1. 1. The current collector is characterized by comprising a high polymer layer, a metal layer and a binder transition layer positioned between the high polymer layer and the metal layer, wherein the binder transition layer comprises a functional polymer, and the functional polymer is a copolymer containing polar groups and flexible chain segments.
  2. 2. The current collector of claim 1, wherein the adhesive transition layer has a thickness of 0.3 μm to 3 μm; Preferably, the polar group includes at least one of a carboxyl group, a hydroxyl group, an amino group, and a sulfonic acid group; preferably, the soft segment includes at least one of a polyether segment, a polyester segment, and a polysiloxane segment.
  3. 3. The current collector of claim 1 or 2, wherein the binder transition layer further comprises nanofillers therein; preferably, the nanofiller comprises at least one of nano silica, nano calcium carbonate and nano clay; preferably, the mass fraction of the nano filler in the adhesive transition layer is 1% -10%.
  4. 4. A current collector according to any one of claims 1 to 3, wherein the material of the metal layer comprises at least one of aluminum, aluminum alloy, copper alloy and stainless steel; Preferably, the thickness of the metal layer is 3-12 μm; preferably, the polymer layer is made of at least one of polyethylene terephthalate, polypropylene and polycarbonate; Preferably, the thickness of the polymer layer is 10-30 μm.
  5. 5. A method of preparing a current collector according to any one of claims 1 to 4, comprising the steps of: Dissolving a functional polymer in an organic solvent to obtain a polymer solution; Applying the polymer solution to the surface of the metal layer, drying and curing to obtain the metal layer with the adhesive transition layer formed on the surface; And compounding the high polymer layer with the metal layer with the adhesive transition layer formed on the surface to obtain the current collector.
  6. 6. The method for preparing a current collector according to claim 5, wherein the organic solvent comprises at least one of N, N-dimethylformamide, dimethyl sulfoxide, and acetone; preferably, the mass fraction of the polymer solution is 3% -15%; preferably, the method of applying the polymer solution to the surface of the metal layer includes any one of knife coating, spray coating, or spin coating.
  7. 7. The method for preparing a current collector according to claim 5 or 6, further comprising adding a nanofiller to the polymer solution, ultrasonically dispersing to obtain a nanofiller-containing mixed solution, applying the nanofiller-containing mixed solution to a surface of a metal layer, drying and curing to obtain the metal layer with a binder transition layer formed on the surface; Preferably, the ultrasonic dispersion time is 30 min-60 min.
  8. 8. The method for preparing a current collector according to claim 6 or 7, wherein the drying temperature is 50 ℃ to 70 ℃, and the drying time is 1h to 4h; preferably, the curing temperature is 75-100 ℃, and the curing time is 1-2 hours; Preferably, the compounding mode is hot pressing, the temperature of the hot pressing is 70-130 ℃, the pressure of the hot pressing is 0.3-3 MPa, and the time of the hot pressing is 3-20 min.
  9. 9. A battery pole piece, characterized in that the electrode pole piece comprises a current collector according to any one of claims 1-5 or a current collector prepared by a method according to any one of claims 6-8.
  10. 10. A battery comprising the current collector of any one of claims 1-5 or the battery pole piece of claim 9.

Description

Current collector and preparation method and application thereof Technical Field The invention relates to the technical field of batteries, in particular to a current collector, a preparation method and application thereof. Background With the rapid development of new energy technology, energy storage devices such as lithium ion batteries are widely applied in the fields of electric automobiles, consumer electronics and the like. The composite current collector is used as a key component of the battery and is formed by compositing a metal layer and a high polymer layer, and the performance of the composite current collector plays a critical role in the overall performance of the battery. In the charge and discharge process of the battery, the metal layer and the polymer layer can expand and contract to different degrees due to the obvious difference of the thermal expansion coefficient and the chemical activity of the metal layer and the polymer layer, so that larger internal stress is generated at the interface of the metal layer and the polymer layer. If the internal stress cannot be effectively released, the problems of interface debonding, crack propagation and the like are caused, and the cycle life and the safety of the battery are reduced. At present, the method in the prior art has limited effect of releasing internal stress at the interface of the two, and is difficult to meet the requirements of a battery with high energy density and long cycle life on the composite current collector. Therefore, the current collector is provided for effectively reducing the internal stress at the interface of the metal layer and the polymer layer so as to improve the electrochemical performance of the battery, and is a technical problem to be solved urgently at present. Disclosure of Invention Aiming at the technical problems in the prior art, the invention aims to provide a current collector and a preparation method and application thereof. In order to achieve the above purpose, the invention adopts the following technical scheme: In a first aspect, the present invention provides a current collector, the current collector including a polymer layer, a metal layer, and a binder transition layer located between the polymer layer and the metal layer, wherein the binder transition layer includes a functional polymer, and the functional polymer is a copolymer containing a polar group and a soft segment. Based on an energy dissipation mechanism, the invention provides a current collector, and since the adhesive transition layer comprises a functional polymer with a specific structure and a specific composition, the functional polymer contains a special structural unit capable of generating internal friction and molecular chain segment movement, and interface stress energy is converted into heat energy and the like to be dissipated through the internal friction and the molecular chain segment movement. Therefore, the adhesive transition layer can effectively dissipate stress energy generated by the interface of the metal layer and the polymer in the battery charging and discharging process, reduce internal stress and improve the structural stability of the composite current collector and the comprehensive performance of the battery. The principle of the energy dissipation mechanism is that the copolymer containing the polar groups and the flexible chain segments is used as the main component of the adhesive transition layer, the energy dissipation mechanism is optimized from the molecular structure level, and the synergistic effect of the polar groups and the flexible chain segments ensures that the polymer can generate enough internal friction when being stressed, ensures the mobility of the chain segments, and realizes the effective conversion and dissipation of energy. The following preferred technical solutions are used as the present invention, but not as limitations on the technical solutions provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solutions. Preferably, the thickness of the adhesive transition layer is 0.3 μm to 3 μm, and may be, for example, 0.3 μm, 0.5 μm, 0.7 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.3 μm, 2.6 μm, 2.8 μm, or 3 μm, etc. By controlling the thickness of the adhesive transition layer within this range, on the one hand, it is ensured that the transition layer is sufficiently thick to continuously and completely cover the interface and has minimal energy dissipation capability, and on the other hand, it is ensured that the transition layer is not too thick, thereby avoiding significant negative effects on conductivity, energy density and mechanical integrity. Preferably, the polar group includes at least one of a carboxyl group, a hydroxyl group, an amino group, and a sulfonic acid group. The polar groups can enhance the interaction be