1、 Introduction to Basic Knowledge

The full English name of electrolytic copper foil is "Electrodeposited Copper Foil", also known as "ED copper foil". Among them, "E" represents Electro - (electrochemistry), and "D" represents Deposited. The full English name of rolled copper foil is "Rolled Annealed Copper Foil", also known as "RA copper foil". Among them, "R" represents Rolled and "A" represents Annealed. The full English name of the composite copper foil is "Electroformed Copper Foil", commonly referred to as "EF copper foil". It is also known as "PET copper foil".

2、 Differences in production processes

1. Electrolytic copper foil is made by electrochemical deposition method, in which copper material is dissolved in sulfuric acid to form copper sulfate electrolyte. Pure copper sulfate electrolyte enters the electrolytic cell of the foil generator, and through the action of direct current, the copper sulfate electrolyte electrodeposits on the surface of the cathode roller, forming the original foil. After continuous rotation of the cathode roller and continuous peeling of the copper foil, it is finally wound into a rolled copper foil. Lithium battery foil is directly subjected to a simple surface treatment with an anti-oxidation process after the foil making machine, while standard foil requires surface treatment through processes such as roughening, curing, galvanizing, and anti-oxidation. The operation is relatively simple and the cost is also low.

2. Rolled copper foil is made by subjecting copper blocks to multiple physical rolling processes to produce the original foil. The copper blocks need to be heated and repeatedly rolled until the desired thickness is achieved. Perform surface treatments such as oil removal, roughening layer, heat-resistant layer, and anti-oxidation treatment as required. This rolling process makes the grain structure of rolled copper foil fibrous, with high ductility and flexibility. The production process of rolled copper foil is more complex and the cost is also higher.

3. Composite copper foil is a thin metal copper coating formed by vacuum coating a thin film of PET, PP, PI and other composite materials to conduct electricity and metalize the film. The main method used is vacuum coating and ion exchange process, with a more complex preparation process. Evaporation is the core process, followed by electroplating. The current mainstream preparation method is a two-step process, which involves magnetron sputtering and water electroplating for thickening. The required equipment includes magnetron sputtering equipment and water electroplating equipment. At present, there are one-step or three-step methods, which can be divided into two categories: chemical one-step method and physical one-step method, both of which are one-step molding methods; The three-step process includes magnetron sputtering, vacuum evaporation, and electroplating with water. After magnetron sputtering, a vacuum evaporation step is added, which requires additional vacuum evaporation equipment.

3、 Differences in physical properties

The grain structure of electrolytic copper foil is columnar, with a relatively regular structure but high brittleness. This makes electrolytic copper foil prone to cracking and fracture during bending and folding, resulting in relatively poor flexibility. The grain structure of rolled copper foil is fibrous, and its ductility is much better than that of electrolytic copper foil. When bending and folding, rolled copper foil will not easily crack, making it very suitable for flexible circuit board applications that require frequent bending. Rolled copper foil can withstand more tension and deformation without easily breaking. Electrolytic copper foil has poor ductility and is prone to cracking during processing due to stretching. The surface of electrolytic copper foil is relatively rough, which can help increase adhesion with other materials in certain applications. However, for some applications of precision circuit boards, low roughness is more conducive to the transmission of electrical signals, while the surface of rolled copper foil is relatively smooth. Due to the mechanical compression during the rolling process, it is more suitable for situations that require high-precision processing.

The conductivity of composite copper foil is superior to traditional copper foil because the structure of composite copper foil allows the copper layer to maintain good conductivity, while optimizing the material combination improves the overall conductivity efficiency.

In terms of thermal conductivity, the thermal conductivity of composite copper foil is poor, especially when the thickness of the copper layer is reduced, such as below 1 μ m, its thermal conductivity will significantly decrease. Composite copper foil, by using polymer materials as substrates, has lower density and lighter weight compared to traditional copper foil. The intermediate layer material of composite copper foil has better ductility and lateral insulation properties, which can provide better protection in the event of mechanical damage to the battery and reduce the risk of internal short circuits.

4、 Differences in application scenarios

Electrolytic copper foil is commonly used in the manufacturing of printed circuit boards (PCBs), flexible circuit boards (FPCs), LED lighting, LCD screens, flat panel televisions, lithium batteries, etc. Electrolytic copper foil is also commonly used in the conductive layer of solar panels to improve their conversion efficiency and stability. In the field of semiconductor packaging, electrolytic copper foil is also used as a metal substrate, which has excellent characteristics such as heat dissipation, lead carrying, and reliability.

Rolled copper foil has been widely used in flexible circuit boards that require frequent bending, movement, or curling due to its good flexibility and fatigue resistance. For example, in applications that require high bending resistance such as foldable phones, wearable devices, and camera modules, rolled copper foil is widely used in flexible copper-clad laminates (FCCL), 5G communication, electromagnetic shielding, heat dissipation substrates, graphene film preparation, aerospace, lithium batteries, intelligent vehicles, drones, and other fields. Rolled copper foil has become an indispensable material due to its unique advantages of high strength, high conductivity, high flexibility, and low roughness.

Composite copper foil can be used in all aspects applicable to electrolytic copper foil, especially in high energy density and high safety requirements. However, composite copper foil has high heat generation, poor thermal conductivity, and low yield rate, so it cannot completely replace electrolytic copper foil at present.

In terms of production cost, rolled copper foil>electrolytic copper foil>composite copper foil

Article source: Internet

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