Industry Knowledge Analysis on Copper Strip Dip Coating

The dip coating process in the industry is generally divided into two types: dip coating with epoxy resin and dip coating with powder. To facilitate distinction, the dip coating with epoxy resin powder is commonly referred to as dip powder, while the process of dipping in liquid PVC glue is called dip coating or dip coating. This article focuses on the analysis of the dip coating process for copper strips. As a mainstream insulation process for copper strips, PVC Dipping Insulated Busbar is gradually being applied in various fields, but it is less used in battery packs and more widely applied in energy storage systems. The differences in application scenarios stem from the matching of process characteristics and scene requirements. The specific analysis is as follows.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copper strip dip coating (dip coating with PVC) refers to the process of uniformly covering the surface of the copper strip with liquid insulating material to form an insulating protective layer. It is one of the core processes of Plastic Dipping Copper Busbar.

The process flow of copper strip dip coating has clear norms. First, the copper strip needs to undergo preheating treatment, which involves heating the copper strip in a furnace to achieve an appropriate activation temperature on the surface of the copper strip, ensuring that the liquid insulating material can quickly adhere and spread evenly during dip coating, and reducing the formation of bubbles. The preheating temperature needs to be precisely adjusted according to the size, material, and type of the liquid insulating material of the copper strip. After preheating, the heated copper strip is quickly immersed in the liquid insulating material. The dip coating time is set according to the required insulation layer thickness, and the copper strip's lifting speed needs to be strictly controlled.

 

If the speed is too fast, it will cause ripples or uneven thickness on the surface of the insulation layer, while if the speed is too slow, it may cause excessive coating in some areas or flow marks. The liquid insulating material needs to maintain a stable viscosity to ensure the uniformity of the coating. Subsequently, the dipped copper strip is sent back into the furnace for heating to undergo the melting, cross-linking, and curing process, and finally be molded. The temperature curve during the plasticization process needs to be precisely controlled to avoid local overheating or incomplete curing. After plasticization, the copper strip is immersed in water for cooling, and then the copper strip is removed from the hooks or bolts for demolding. The finished product needs to undergo post-processing of cutting the insulation layer at the reserved parts to ensure the conductivity of the connection end of the copper strip.

The insulating material used for copper strip dip coating is mainly polyvinyl chloride (PVC) liquid insulating material. This material is composed of PVC resin, plasticizers, stabilizers, fillers, etc. It is in a liquid form at room temperature. It has the advantages of low cost and good fluidity, making it suitable for mass production. The operating temperature range can reach -40℃ - 125℃, and the insulation strength can reach 20 - 28 kV/mm, which can meet the basic insulation requirements of battery power packs and energy storage electrical scenarios. It is the core insulating raw material of PVC Coated Bus Bars.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copper strip dip coating has significant process characteristics. Firstly, the insulation performance is stable, capable of withstanding voltages of 3500V AC/DC and above, with reliable insulation effect, effectively preventing current leakage, and meeting the core performance requirements of Insulated BusBar (insulated copper strips). Secondly, the coating uniformity is good. Due to the good fluidity of the liquid insulating material, it can form a relatively uniform insulation layer after covering the surface of the copper strip, especially suitable for copper strips with complex shapes. Thirdly, the adhesion is strong.

 

After plasticization, the liquid insulating material combines tightly with the surface of the copper strip, with a peel strength of ≥ 4N/cm, and is not prone to detachment, ensuring the long-term stability of the dip-coated copper strip. Meanwhile, the copper bars produced by this process have good corrosion resistance and can withstand the erosion of common humid and dusty environments. They perform well in salt spray tests (5% NaCl solution, 35°C, 192 hours) and can be adapted to various complex working conditions.

From the perspective of application scenarios, the adaptability of the copper bar impregnation process shows significant differences in scenarios. In the field of power batteries, their application is subject to many restrictions. Firstly, it is due to the limitations of space and weight. Power battery packs are extremely sensitive to space and weight. Impregnation will increase the thickness and weight of the copper bars, and the application space within BDU and modules is limited, which is not conducive to the pursuit of high energy density and lightweight requirements of the power battery system.

 

This also makes the Insulated Flexible Copper Bus Bar for Power Battery Pack less likely to adopt the impregnation process. Secondly, it is due to the heat dissipation limitation. Power batteries generate a large amount of heat during charging and discharging, and the insulating layer formed by impregnation (especially the thicker coating) will hinder heat dissipation, possibly causing the local temperature to be too high, affecting battery performance and safety.

In the energy storage field, the impregnation copper bar process has a good application prospect. Energy storage systems are mostly fixed installations, with relatively loose restrictions on space and weight. The good insulation and corrosion resistance of the impregnated copper bars can adapt to humid, dusty, and other complex environments, ensuring the stable operation of the energy storage system. At the same time, energy storage systems have large capacities and extremely high safety requirements. The high insulation performance of the impregnated copper bars can effectively reduce the risk of leakage, meeting the safety operation requirements of the energy storage system, and becoming the preferred process type for Dipping Busbar for Connection.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In conclusion, the impregnation process of copper bars has significant advantages in insulation performance and cost control, but is limited by factors such as space, weight, and heat dissipation. It is less used in the field of power batteries. However, in scenarios with lower requirements for space and weight, such as energy storage, its adaptability is stronger, and it has a good application prospect. It can provide reliable guarantees for the safe and stable operation of electrical systems, and also provides process support for the development of Plastic Dipping Electric Copper Busbar Custom Made.