Search

CN-121983580-A - Functional current collector for improving thermal runaway safety, preparation method thereof, pole piece and battery

CN121983580ACN 121983580 ACN121983580 ACN 121983580ACN-121983580-A

Abstract

The invention discloses a functional current collector for improving thermal runaway safety, a preparation method thereof, a pole piece and a battery, wherein the functional current collector comprises a shape memory polymer base film, a conductive polymer and a conductive polymer, wherein the shape memory polymer base film is formed by compounding a polymer material and a shape memory polymer; the alumina priming layer is arranged on the front and back surfaces of the shape memory polymer base film; and the aluminum metal coating is arranged on the aluminum oxide priming layer. The invention effectively overcomes the defects of the existing aluminum functional current collector through the structural composition and the preparation process improvement of the functional current collector, and has remarkable advantages in the aspects of thermal runaway protection, material consistency improvement, structural stability and the like of the battery.

Inventors

  • SUN PENGFEI
  • LI XUEFA

Assignees

  • 扬州纳力新材料科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260122

Claims (10)

  1. 1. A functional current collector for improving thermal runaway safety, comprising: the shape memory polymer base film is formed by compounding a polymer material and a shape memory polymer; the alumina priming layer is arranged on the front and back surfaces of the shape memory polymer base film; and the aluminum metal coating is arranged on the aluminum oxide priming layer.
  2. 2. The functional current collector for improving thermal runaway safety according to claim 1, wherein the mass ratio of the shape memory polymer to the polymer material in the shape memory polymer base film is 1.4-2:1, and the thickness of the shape memory polymer base film is 5-12 μm.
  3. 3. The functional current collector for improving thermal runaway safety according to claim 1, wherein the shape memory polymer base film is a shape memory polymer-polymer material-shape memory polymer three-layer sandwich structure film.
  4. 4. The functional current collector for improving thermal runaway safety according to claim 1, wherein the thickness of the aluminum oxide primer layer is 40-200 nm, and the thickness of the aluminum metal coating layer is 0.7-5 μm.
  5. 5. The method for producing a functional current collector for improving thermal runaway safety according to any one of claims 1 to 4, comprising the steps of: s1, drying a high molecular material and a shape memory polymer to remove water; S2, respectively heating and melting the shape memory polymer and the high polymer material, adding half of the melted shape memory polymer into a die to form a uniform bottom layer, then adding the melted high polymer material to uniformly spread the bottom layer to form a middle layer, and then adding the melted shape memory polymer to uniformly spread the middle layer to form a top layer; S3, extruding the film through a die, performing longitudinal stretching and transverse stretching, and shaping to obtain a shape memory polymer base film; s4, preparing an alumina priming layer on the front and back surfaces of the shape memory polymer base film; s5, preparing an aluminum metal coating on the aluminum oxide priming layer.
  6. 6. The method for preparing a functional current collector for improving thermal runaway safety according to claim 5, wherein in the step S3, the shaping comprises heat shaping and air cooling shaping, the temperature of the heat shaping is 190-210 ℃, the time is 3-6 seconds, and the air cooling shaping is to cool the functional current collector to 45-50 ℃ through air cooling.
  7. 7. The method for producing a functional current collector for improving thermal runaway safety according to claim 5, wherein the shape memory polymer is selected from the group consisting of polyurethane, polycaprolactone, and crosslinked polyolefin.
  8. 8. The method for preparing a functional current collector for improving thermal runaway safety according to claim 5, wherein the aluminum oxide primer layer and the aluminum metal coating are prepared by a magnetron sputtering or evaporation method.
  9. 9. A pole piece characterized by comprising the functional current collector for improving thermal runaway safety prepared by the method of any one of claims 1-4 or any one of claims 5-8.
  10. 10. A battery comprising the electrode sheet of claim 9.

Description

Functional current collector for improving thermal runaway safety, preparation method thereof, pole piece and battery Technical Field The invention relates to the technical field of batteries, in particular to a functional current collector for improving thermal runaway safety, a preparation method thereof, a pole piece and a battery. Background The functional current collector is used as an innovative battery material, and adopts a sandwich structure design of a metal conducting layer, a high polymer base material and a metal conducting layer, wherein the middle high polymer layer (such as PET and PP) has insulation and flame retardance. When the battery is subjected to mechanical abuse such as puncture or collision, the polymer substrate can be quickly fused to form a 'point open circuit', so that a current path is effectively blocked, and the thermal runaway diffusion is prevented. The mechanism fundamentally avoids the problem of short circuit caused by metal burrs of the traditional current collector, and the safety of the battery is obviously improved. At present, the technology has been applied to a kylin battery (carried on a vehicle type such as extremely krypton 001, extremely krypton 009 and the like) and a wide-range automobile An Danxia battery 2.0 in the Ningde era, and the effectiveness of the technology in improving the safety of a high-energy-density battery is proved through practical verification. For example, the Ningde times NP2.0 no thermal diffusion technology is just through the application of functional current collectors, greatly reducing the risk of thermal runaway of the battery. However, the existing functional current collector technology still has significant drawbacks. The safety performance of the high-polymer base film mainly depends on the fusing of the high-polymer base film at high temperature, so that the breaking of the metal layer is promoted to realize the breaking. However, in practical application, under the same needling verification condition, the single-plated product still has a fire phenomenon. Subsequent studies revealed that the multiple plating technique was able to achieve effective circuit breaking because the brittle aluminum oxide layer produced microcracks during needling, which in turn led to cracking of the aluminum layer, whereas the single plated product lacked this brittle mechanism, resulting in limited fusing. In addition, the aluminum splashing phenomenon generated in the evaporation process can form holes on the film surface to cause pinhole defects, so that the material defect rate in the manufacturing process is increased, the material consistency is reduced, and the overall safety of the battery is further weakened. Disclosure of Invention The invention aims to provide a functional current collector for improving thermal runaway safety, a preparation method thereof, a pole piece and a battery, which obviously improve the thermal runaway protection capability, material consistency and structural stability of the battery, simultaneously maintain the compatibility with the existing battery production line, and provide a low-cost and mass-producible solution for high-safety batteries. In order to achieve the above purpose, the technical scheme provided by the invention is as follows: a first aspect of the present application provides a functional current collector for improving thermal runaway safety, comprising: the shape memory polymer base film is formed by compounding a polymer material and a shape memory polymer; the alumina priming layer is arranged on the front and back surfaces of the shape memory polymer base film; and the aluminum metal coating is arranged on the aluminum oxide priming layer. In order to optimize the technical scheme, the specific limitations adopted further comprise: in the shape memory polymer base film, the mass ratio of the shape memory polymer to the polymer material is 1.4-2:1, and the thickness of the shape memory polymer base film is 5-12 mu m. Further, the shape memory polymer base film is a three-layer sandwich structure film of shape memory polymer, polymer material and shape memory polymer. The thickness of the aluminum oxide priming layer is 40-200 nm, and the thickness of the aluminum metal coating layer is 0.7-5 mu m. The second aspect of the present application provides a method for manufacturing a functional current collector for improving thermal runaway safety, comprising the steps of: s1, drying a high molecular material and a shape memory polymer to remove water; S2, respectively heating and melting the shape memory polymer and the high polymer material, adding half of the melted shape memory polymer into a die to form a uniform bottom layer, then adding the melted high polymer material to uniformly spread the bottom layer to form a middle layer, and then adding the melted shape memory polymer to uniformly spread the middle layer to form a top layer; S3, extruding the film through a die, performin