Copper foil is actually a kind of negative electrolytic material. Copper foil is a thin, continuous metal foil deposited on the substrate of the circuit board. As a conductor of PCB, copper foil is easy to be bonded to the insulation layer, receive the printing protection layer, and form a circuit pattern after corrosion. Copper foil has the characteristics of low surface oxygen, which can be attached to various substrates, such as metals, insulating materials, etc., and has a wide range of temperature applications. It is mainly used for electromagnetic shielding and anti-static. The conductive copper foil is placed on the substrate and combined with the metal substrate, which has excellent conductivity and provides electromagnetic shielding effect.

Copper foil is classified in different ways as follows

1. 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)；

2. 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);

3. It can be divided into Electrolytic copper foil 、 Calendered copper foil And leather copper.

4. According to the application scope, it can be divided into:

Copper clad laminate (CCL) and copper foil for printed circuit board (PCB): CCL and PCB are the most widely used fields of copper foil. At present, PCB has become an indispensable component for most electronic products to achieve circuit interconnection. At present, copper foil has become the key material of PCB that plays the role of supporting and interconnecting components in electronic products. At present, electrolytic copper foil is mostly used in CCL and PCB industries;

Copper foil for lithium ion secondary battery: according to the working principle and structural design of lithium ion battery, graphite, petroleum coke and other negative materials need to be coated on the conductive collector. Copper foil has become the negative collector of lithium ion battery due to its good conductivity, soft texture, mature manufacturing technology and relatively low price;

Copper foil for electromagnetic shielding: it is mainly used in some fields requiring electromagnetic shielding, such as hospitals, communications and military affairs. Due to the limitation of the width of the rolled copper foil, the electromagnetic shielding copper foil is mostly electrolytic copper foil.