Vacuum Coating Machinery for Composite Copper Foil Used in Lithium Batteries.

Composite copper foils are engineered utilizing a 'sandwich' structure that comprises a metal layer, a polymer film, and an additional metal layer. This process incorporates essential techniques such as magnetron sputtering and aqueous plating. Unlike conventional copper foils, which are predominantly manufactured through roller pressing or electrolysis, composite copper foils are produced by magnetron sputtering a metal layer measuring 30-70 nm onto substrates such as PET, PP, and PI, which possess a thickness of 3-8 μm. This method yields a square resistance of approximately 0.5-2 ohms, facilitating the metallized of the substrate's surface. Following this, the metal layer is further thickened to 1 μm or greater through aqueous electroplating, culminating in a composite copper foil with an overall thickness of 5-10 μm, intended to serve as a replacement for electrolytic copper foils that typically range from 4.5-9 μm in thickness.

Guangdong Tecsun Technology has successfully developed the first mass-produced vacuum coating equipment for composite copper foils in China, significantly enhancing safety measures. The organic insulating layer situated within the composite copper foil offers infinite resistance to the circuit system during instances of thermal runaway, and is inherently non-combustible. This characteristic diminishes the likelihood of battery combustion, fire, and explosion, thereby enhancing overall battery safety.

Furthermore, this innovation effectively increases the energy density of the battery. The use of PET material, which is lighter in weight, results in a reduction of the overall mass of the PET copper foil. This is achieved by substituting the central portion of the metal foil with a layer of PET, leading to a weight reduction of approximately 60% compared to traditional copper foil, without any increase in overall thickness. Additionally, the reduction in copper foil thickness contributes to lower raw material costs, as the plating technology employed is more efficient than traditional extension methods, allowing for thinner materials. The incorporation of the PET layer also decreases the quantity of copper foil required, enabling manufacturers to effectively address rising metal prices and achieve cost savings of approximately 40%

The newly developed composite copper foil material is produced using magnetron sputtering vacuum coating technology, which facilitates the metallization of the surface of the organic film's initial material. This process enhances the material's conductivity while ensuring the density of the film layer and the strength of the adhesion. The advantages of magnetron sputtering vacuum coating technology include excellent stability, repeatability, and uniformity, making it suitable for large-area applications. Additionally, it produces a dense film layer with strong bonding properties and offers process flexibility. Following the completion of the magnetron sputtering process, a water electroplating thickening method is employed to increase the thickness of the copper layer to approximately 1 micrometer, thereby meeting the conductivity requirements of the collector.

Guangdong Tecsun possesses extensive expertise in the design and manufacturing of vacuum coating technology and equipment. The company has also amassed over five years of experience in the processes and equipment related to composite copper foil materials.