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CN-118322671-B - Soft package and solid battery packaging steel-plastic film and preparation method thereof

CN118322671BCN 118322671 BCN118322671 BCN 118322671BCN-118322671-B

Abstract

The application belongs to the technical field of lithium battery packaging materials, and particularly relates to a soft package and solid battery packaging steel-plastic film and a preparation method thereof. The soft package and solid battery packaging steel-plastic film sequentially comprises a polypropylene layer, a hot melt adhesive layer, an ultrathin steel foil layer, a hot melt adhesive layer and a polyethylene terephthalate layer from inside to outside, wherein the ultrathin steel foil layer is an ultrathin steel foil with both sides etched by reaction particles. The soft package and solid battery packaging steel-plastic film solves the problem that the existing aluminum-plastic film cannot meet the requirements of the market on the performance thickness of battery soft package packaging, has good packaging effect, light weight, can prevent air, especially oxygen, from penetrating, has good deformability and strength, can prevent the battery cell from being damaged by the outside, and ensures the service life of the battery cell.

Inventors

  • XIA WENJIN
  • SHI YALI
  • ZHANG JIEBING
  • TAO JIAN
  • Han Zitao

Assignees

  • 浙江锂盾新能源材料有限公司
  • 浙江锂盾储能材料技术有限公司

Dates

Publication Date
20260508
Application Date
20240506

Claims (7)

  1. 1. A soft package and solid battery packaging steel-plastic film is characterized by sequentially comprising a polypropylene layer, a hot melt adhesive layer, an ultrathin steel foil layer, a hot melt adhesive layer and a polyethylene terephthalate layer from inside to outside, wherein the ultrathin steel foil layer is an ultrathin steel foil with both sides being etched by reactive particles, and the thickness of the ultrathin steel foil layer is 30um; The preparation method of the modified carbon fiber comprises the steps of heating concentrated nitric acid with the mass concentration of 33-68% to 60-80 ℃, adding the carbon fiber for oxidation etching for 2-4h, washing for 3-5 times by tetrahydrofuran, drying to obtain carbon oxide fiber, mixing ethanol and deionized water with the mass ratio of 1 (1.5-3), adding a silane coupling agent, stirring and mixing uniformly, dispersing the carbon oxide fiber in the mixture, carrying out ultrasonic treatment, filtering and drying to obtain the modified carbon fiber.
  2. 2. The steel-plastic film for soft package and solid state battery package of claim 1, wherein the steel foil etching gas is one selected from SF6, CF4, and CHF 3.
  3. 3. The steel plastic film for soft package and solid state battery package of claim 1, wherein the thickness of the hot melt adhesive layer is 1-5um.
  4. 4. The steel-plastic film for soft package and solid state battery package of claim 1, wherein the thickness of the polypropylene layer is 12-20um, and the thickness of the polyethylene terephthalate film is 10-30um.
  5. 5. A preparation method of a soft package and solid battery packaging steel-plastic film is characterized by comprising the following steps of (1) carrying out reactive ion etching on two sides of a steel foil by utilizing a reactive ion etching technology, (2) carrying out reactive ion etching on the surface of a hot melt adhesive, (3) carrying out double-pressure preheating compounding on polypropylene and the hot melt adhesive, preheating the steel foil, carrying out double-pressure preheating compounding on the hot melt adhesive and polyethylene terephthalate, then compounding the preheating layer by a double-pressure hot roller, and carrying out hot press molding by a double-pressure hot roller, and (4) carrying out forced air convection cooling heat dissipation, and winding to obtain a steel-plastic film finished product.
  6. 6. The method for preparing the steel-plastic film for soft package and solid battery package of claim 5, wherein the temperature of the double-pressure preheating is 80-120 ℃, the temperature of the double-pressure hot roller is 100-160 ℃, and the temperature of the secondary double-pressure hot roller is 130-180 ℃.
  7. 7. The method for preparing the steel-plastic film for soft package and solid battery package of claim 5, wherein the composite pressure of the double-pressure preheating, double-pressure hot roller and the secondary double-pressure hot roller is 1000-2000Kg.

Description

Soft package and solid battery packaging steel-plastic film and preparation method thereof Technical Field The application belongs to the technical field of lithium battery packaging materials, and particularly relates to a soft package and solid battery packaging steel-plastic film and a preparation method thereof. Background The polymer lithium battery has high energy density and good safety performance, is a main energy source provider of digital and IT products, and becomes an important development direction along with the development requirements of mobile or medium-sized and small-sized energy storage devices and irregular and irregularly-shaped power lithium batteries. In recent years, with the progress of the soft pack battery technology and the solid state battery technology, the soft pack battery demand is increasing and the mass production of the solid state battery is making the corresponding critical material demand expected to increase explosively. The existing soft-packed battery and solid-state battery still use an aluminum plastic film as an important packaging material to seal and protect battery cells, but as soft-packed battery and solid-state battery manufacturers continuously improve energy density and battery capacity, more diversified requirements are provided for the thickness and performance of the packaging material, and if the thickness of a metal aluminum foil is required to be reduced to below 30 mu m, the materialization characteristics of a negative electrode and an electrolyte are hardly damaged due to the fact that a small amount of air is permeated, so that the barrier property of the soft-packed material is reduced, and environmental gas and water vapor permeate into and corrode the battery cells, so that the service life of the battery is influenced. Disclosure of Invention Aiming at the problem that the existing aluminum-plastic film cannot meet the performance thickness requirement of the soft package packaging of the battery in the market, the physical and chemical characteristics of the electrode and the electrolyte are prevented from being damaged due to impurity infiltration, and the barrier property of the soft package battery or the solid battery is improved, the application provides the soft package and solid battery packaging steel-plastic film and a preparation method thereof. In a first aspect, the application provides a soft package and solid-state battery packaging steel-plastic film, which adopts the following technical scheme: The soft package and solid battery packaging steel-plastic film sequentially comprises a polypropylene layer, a hot melt adhesive layer, an ultrathin steel foil layer, a hot melt adhesive layer and a polyethylene terephthalate layer from inside to outside, wherein the ultrathin steel foil layer is ultrathin steel foil with both surfaces being etched by reactive ions. By adopting the technical scheme, the soft package and the solid-state battery package can improve the heat dissipation of the battery and prevent the battery from causing the problem of battery heat under the discharge condition, the soft package and the solid-state battery package steel-plastic film are formed by adopting five layers of bonding, and the outermost layer is a polyethylene terephthalate layer, so that the soft package and the solid-state battery package steel-plastic film has the advantages of good mechanical property, high impact strength, good folding endurance, low gas and water vapor permeability and excellent gas resistance, water, oil and peculiar smell performances. The polypropylene layer has better solvent resistance and acid resistance due to chemical inertia, and improves the electrolyte resistance of the steel plastic film by bonding with the hot melt adhesive layer. On the basis, the ultrathin steel foil layer is subjected to double-sided reactive ion etching by adopting a reactive ion etching technology, hydrogen bonds are formed between the layers, the interlayer bonding strength is improved, the insulation and barrier properties of the steel-plastic film can be greatly improved by the double-sided film coating of the steel foil, the cohesiveness and corrosion resistance of the steel foil are improved, and the water and oxygen barrier effect is enhanced. The soft package and solid battery package steel-plastic film has good package effect, light weight, capability of preventing air, especially oxygen, from penetrating, good deformation capability and strength, and capability of preventing damage to battery cells from the outside. In a specific embodiment, the steel foil etching gas is selected from one of SF6, CF4, CHF 3. By adopting the technical scheme, the fluorine-containing plasma gas is selected as etching gas, so that the double-sided reactive ion etching of the steel foil reacts with etching high-energy particles in a short time, stronger hydrogen bonds or interaction forces such as C-F bonds or Si-F bonds are formed on the surface