Industry knowledge details of dipped insulated busbar products

PVC Dipping Insulated Busbar refers to immersing processed copper or aluminum busbars in liquid or powdered polyvinyl chloride (PVC) materials and forming a continuous, dense plastic coating with excellent electrical insulation properties on the surface of the conductor through thermal adsorption and solidification processes. Different from heat-shrinkable sleeve coating or electrostatic powder spraying, the core of the dip molding process is to use the preheated metal conductor's own heat to evenly absorb and level the contacting dip molding liquid, and then solidify and shape the coating through high-temperature plasticization, thereby achieving a tight bond without gaps between the coating and the substrate. This "rigid end, flexible middle" or fully insulated structural design makes it widely used in high and low voltage power distribution equipment, new energy vehicles, rail transit and other fields. According to differences in product form and function, it covers a variety of types: Insulated Custom Copper Bus Bar with PVC Dipping emphasizes customized production according to customer drawings to meet non-standard size and special shape requirements; PVC Dipped Insulated Bus Bar is the most common name in the industry, specifically referring to standard products that have undergone a complete dipping process.

 

In the field of new energy power batteries, Insulated Flexible Copper Bus Bar for Power Battery Pack requires that the conductor itself be flexible (for example, made of multiple layers of thin copper foil laminated), and the external PVC coating can deform following the bending of the busbar, which is suitable for complex and compact series or parallel connections between battery modules. In addition, the two names of Plastic Dipping Copper Busbar and Plastic Dipping Electric Copper Busbar Custom Made further emphasize the technical characteristics of "plastic wrapping" in the dipping process and the service capabilities of on-demand customization. In the transition section connecting fittings and busbars, Soft Connection Copper Busbar is sometimes used as the middle flexible section, and then the entire body is dipped in plastic to achieve both insulation and vibration reduction effects. PVC Coated Bus Bars is a general term that refers to all busbar products treated with PVC coating, while Busbar Isolation focuses on describing the core role of the impregnation layer in electrical isolation - it can effectively prevent phase-to-phase short circuits or ground flashovers, and is a key technical measure to ensure the safe operation of power transmission and transformation systems.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The manufacturing process of PVC dipped insulated busbar is a multi-step precision process including conductor molding, pre-treatment, preheating, dipping, plasticizing and cooling. The parameter control of each step directly affects the insulation performance and service life of the final product. The starting point of the process is the mechanical processing of copper strips: copper strips or plates are formed into the shape required by the customer through punching, bending, drilling and other processes. At this stage, all edges must be chamfered or deburred (the chamfer radius is usually 1~2mm), because sharp edges will not only produce a Faraday effect with a thin coating during dipping, but will also become an electric field concentration point in subsequent use, increasing the risk of partial discharge. The processed copper bars immediately enter the pre-treatment process - first, use an alkaline degreasing agent or ultrasonic cleaning to remove the stamping oil and cutting fluid on the surface, then rinse with pure water and dry thoroughly. For Insulated Flexible Copper Bus Bar for Power Battery Pack, since oil stains may be hidden in the gaps on the surface of the flexible conductor (laminated copper foil), the cleaning time needs to be extended or multi-step cleaning is required. The last step of pretreatment is chemical conversion treatment (such as chromate passivation or organosilane treatment) to form a micron-scale chemical film on the surface of the copper bar. This film layer can significantly enhance the adhesion between the PVC coating and the copper matrix and prevent the coating from peeling off during use.

 

After the pre-treatment is completed, the copper bus bar is fixed on the dipped bracket. For PVC Dipped Insulated Bus Bar, iron wire or a special hanger is usually used for hanging. The suspension point should be selected on a non-critical surface (such as the end edge of the copper bar) to facilitate subsequent repairs. Then enter the preheating process: put the suspended copper row into a hot air circulation oven for heating. The preheating temperature is usually set between 180°C and 250°C. The specific value depends on the cross-sectional size and heat capacity of the copper row. The purpose of preheating is to allow the copper bar to store enough heat. When immersed in normal temperature or slightly hot PVC dipping liquid, this heat will be quickly transferred to the contacting dipping liquid, causing it to melt and evenly adsorb on the surface of the copper bar. Insufficient preheating will cause the coating to be too thick and have poor leveling properties. Excessive preheating may increase the oxidation of the copper bar surface or cause the chemical conversion coating to fail. After preheating is completed, the copper bars are quickly immersed in a dip tank containing liquid PVC. The length of the immersion time determines the thickness of the initial coating - immersion for 2 to 5 seconds usually results in a coating of 0.5 to 1.0 mm.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The material system of PVC dipped insulated busbar mainly includes three parts: conductive substrate, dipped coating material and auxiliary processing materials. The conductive substrate usually uses T2 copper or C1100 electrolytic tough copper, with a copper content of not less than 99.90% and a conductivity of more than 97% IACS to ensure low heat generation and low power loss during large current transmission. For applications that require weight reduction, 6061 or 6101 aluminum alloys can also be used as the base material, but in this case the aluminum needs to undergo special chemical conversion treatment (such as zinc-based phosphating) before dipping to enhance the adhesion between the coating and the aluminum base. The dipping coating material is polyvinyl chloride (PVC), which is a thermoplastic polymer material with high volume resistivity and dielectric strength under normal conditions. In order to adapt to different application needs, the PVC formula can be customized in many ways: Insulated Custom Copper Bus Bar with PVC Dipping usually adjusts the plasticizer content according to the working environment temperature - the higher the plasticizer ratio, the softer the coating, which is suitable for occasions that require bending or vibration (such as Insulated Flexible Copper Bus Bar for Power Battery Pack); conversely, a low plasticizer ratio results in a high coating hardness and good wear resistance, making it suitable for distribution cabinets with a greater risk of frequent plugging and unplugging or mechanical scratches.

 

In terms of flame retardant performance, by adding antimony trioxide or phosphate ester flame retardants, the PVC coating can reach the UL94 V-0 level, which means it will self-extinguish when exposed to fire and will not produce dripping material to ignite peripheral devices. In addition, for outdoor or high-humidity environments, antioxidants and ultraviolet absorbers will be added to the formula to delay the aging discoloration and mechanical properties of PVC. The color of PVC Coated Bus Bars is another important material parameter - the common black is used for general insulation, the orange is specially used for high-voltage circuits of new energy vehicles (in line with the warning requirements of international standards for high-voltage components), and the three colors of red, yellow, and green are used for the phase sequence identification of the three-phase AC bus. During the production process of the Plastic Dipping Copper Busbar, masking materials (such as high-temperature resistant tape or silicone masks) are also needed to achieve a partially exposed design - that is, only the non-connected areas are dipped in plastic, and the tinned or bare copper areas reserved at both ends are used for bolt tightening. Finally, for products with higher Busbar Isolation requirements, an electron beam irradiation cross-linking process is sometimes used after dipping to transform the PVC molecular chains from a linear structure to a three-dimensional network structure, thereby significantly improving the heat resistance and solvent resistance of the coating. However, this post-processing is usually only used in high-end customized products.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PVC-dipped insulated busbars play an indispensable role in industries such as power transmission and transformation, new energy storage, industrial automation and rail transit. In high and low voltage switch cabinets, especially compact distribution boxes or capacitor compensation cabinets, it is difficult to meet safety regulations for the distance between bare copper bars or to the ground due to space constraints. In this case, the use of PVC Dipped Insulated Bus Bar can effectively reduce the electrical gap. At the same time, the coating surface is smooth and difficult to accumulate dust, reducing the risk of surface discharge caused by contamination.

 

For industrial power distribution rooms that often require maintenance or renovation, Insulated Custom Copper Bus Bar with PVC Dipping can be accurately bent and coated according to the on-site layout, allowing the busbar to perfectly bypass existing cooling fans, relays and other obstacles, greatly improving the space utilization in the cabinet. In new energy vehicles and energy storage systems, the internal environment of the power battery pack is extremely harsh: the battery core will expand and contract in the thickness direction during the charge and discharge cycle, and the continuous vibration during vehicle driving also places flexible requirements on the connectors. Insulated Flexible Copper Bus Bar for Power Battery Pack is born for this purpose - its internal flexible conductor (such as laminated copper foil or braided tape) can absorb the expansion displacement of the battery core, and the external PVC dipped layer provides insulation protection against electrolyte corrosion and vibration wear.

 

In addition, in series or parallel connection between cells, the Plastic Dipping Copper Busbar can ensure that there is no accidental contact between high-voltage circuits, and the orange or black coating makes it easy to identify high-voltage risks. In the field of rail transit, the traction converter cabinets and auxiliary power cabinets at the bottom of trains are often in harsh environments with high humidity and high salt spray. PVC Coated Bus Bars rely on their continuous and seamless impregnation layer to effectively isolate the corrosion medium from corroding copper conductors, significantly extending the maintenance cycle. At the same time, for long-span bus bridges or connections that need to pass through partitions, Dipping Busbar for Connection can provide additional insulation reinforcement at the through holes to prevent insulation damage due to vibration and friction.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Whether you need a vibration reduction connection solution for PVC Dipping Insulated Busbar, or have special pressure or temperature resistance requirements for Busbar Isolation, our engineers can issue a feasibility assessment and sample quotation after receiving the drawings.