Copper foil is a key conductive material in lithium ion batteries and printed circuit boards. At present, most of our copper foils are used as anode materials for lithium ion batteries. With the development of lithium-ion batteries towards high capacity, thin, high-density and high-speed, copper foil is also moving towards ultra-thin and low profile (the surface roughness of copper foil is 2 μ M below), high strength, high ductility and other high-quality and high-performance directions, and its performance is closely related to the copper foil structure and surface treatment. At present, the advanced copper foil production technology and copper foil surface treatment technology are monopolized by the United States and Japan.

Copper foil classification

It can be divided into thick copper foil (more than 70 μ m) Regular thickness copper foil (more than 18 μ M but less than 70 μ m) Thin copper foil (more than 12 μ M but less than 18 μ m) Ultra thin copper foil (less than 12 μ m)；

According to the surface condition, it can be divided into single-sided treated copper foil (single-sided wool), double-sided treated copper foil (double-sided thick), smooth treated copper foil (double-sided wool), double-sided glossy copper foil (double-sided wool) and very low profile copper foil (VLP copper foil);

It can be divided into Electrolytic copper foil and Calendered copper foil 。

1. Electrolytic copper foil is formed by depositing copper ions in electrolyte on the round cathode roller of smooth rotating stainless steel plate (or titanium plate). The surface of copper foil close to the cathode roller is called smooth surface, and the other surface is called rough surface.

2. Calendered copper foil is generally made of copper ingot as raw material through hot pressing, tempering toughening, scaling, cold rolling, continuous toughening, pickling, calendering, degreasing and drying processes.

Comparison between calendered copper foil and electrolytic copper foil

The rolled copper foil has a smoother surface and higher density. It is mostly used for flexible printed circuit boards. The rolled copper foil has a lamellar crystal structure, which is superior to the electrolytic copper foil with columnar texture in flexibility. The electrolytic copper foil is mainly used in the manufacturing of rigid printed circuit boards and lithium batteries. The electrolytic copper foil has a simpler production process than the rolled copper foil, As well as lower production costs, if there is no special case for the toughness of copper foil, more electrolytic copper foil is selected.