What is lithium composite copper foil

The preparation methods of polymer composite copper foil are roughly divided into three categories, and the specific preparation processes are as follows:

• First, the copper powder, conductive agent, and glue are evenly mixed to obtain copper powder slurry, and then the slurry is coated on the polymer base film by a gravure coating process, and the copper layer is thickened on the prepared base film by electrolytic copper foil process, and the composite copper foil is finally produced.
• Because of this process in the preparation of slurry, copper powder and glue compatibility and dispersion is poor, copper powder is easy to agglomerate, resulting in base film square resistance difference being large, and the preparation of composite copper foil surface density uniformity is poor.
• Secondly, polyester film is used as the insulating layer, and the adhesive is coated on the surface of the polyester film by a dry laminating machine, then the polyester film is dried by a drying machine, and then the electrolytic copper foil and polyester film are bonded with composite copper foil by pressure roller machine.
• The composite copper foil prepared by this process has defects such as poor peeling resistance, which will lead to delamination or peeling phenomenon in the process of use.
• Third, magnetron sputtering plus an aqueous plating process is used for the production of composite copper foil.
• The specific preparation process is roughly divided into two steps, as shown in the figure.
• The first process is on the 4µm (material PET/PI) polymer film, magnetron sputtering deposition of particles process technology, through the use of high kinetic energy of the charge energy particles, the bombardment of 99.999% purity of the copper target, so that the copper atoms to obtain enough energy sputtering, sputtering deposition of the base film surface of the copper seed layer of 0.02 ~ 0.08µm, so that the polymer surface with metal properties, to get the A 4.5µm metalized base film is obtained.
• In the second process, water electroplating is used to thicken both sides of the metalized film to 1µm, resulting in a new polymer composite copper foil with a thickness of 6.5µm. The composite copper foil prepared by this process is characterized by strong resistance to peeling, good ductility, uniform thickness, etc., and has been applied in new energy storage equipment in China.
• Comparison of the above three processes, its advantages and disadvantages are also obvious. In the first two the equipment requirements are lower, and less investment; and the use of magnetron sputtering technology for the equipment and production conditions are more demanding, and invest more money. But as far as product quality is concerned, the latter is better, which is also the trend of the future development of the copper foil industry.