Research on High-Temperature Resistant Heat-Shrinkable Tubing Technology for Electrical Insulation: Enhancing Safety Protection for High-Voltage Busbar Systems

With the rapid development of new energy, power electronics, and intelligent power distribution systems, high-voltage switchgear is increasingly trending toward miniaturization and high power density. Carrying higher currents within limited spaces exacerbates issues such as temperature rise in internal conductors, electric field concentration, and insulation reliability. As a critical insulation and protection material for high-voltage electrical equipment, heat-shrink tubing must not only provide excellent insulation performance but also meet requirements for long-term heat resistance, resistance to mechanical damage, and adaptability to complex environments.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In high-voltage switchgear, power distribution cabinets, and new energy power equipment, copper or aluminum busbars are commonly used to transmit electrical energy. Because busbars generate heat during long-term operation-and given that some irregularly shaped conductors face constraints such as limited installation space or sharp edges-exposed conductors are prone to risks like partial discharge, surface tracking, and even insulation breakdown. Consequently, encapsulating conductors with heat-shrinkable insulation materials has become a vital measure for enhancing equipment safety.

 

In practical applications, some conductor configurations are complex, requiring heat-shrink tubing with a high shrink ratio to ensure smooth installation on-site. Furthermore, to meet specific mounting requirements, the insulation layer may need to undergo perforation or mechanical processing; this places higher demands on the material's tear resistance and long-term stability. For instance, when employing customized copper busbar connections with heat-shrink tubing, the insulation layer must not only ensure electrical isolation but also withstand mechanical stress variations in complex assembly environments.

 

Traditional heat-shrink tubing for power applications typically utilizes polymer materials such as ethylene-vinyl acetate (EVA) as the primary base resin, offering good flexibility and insulation properties. However, as operating temperatures rise and equipment designs become more compact, standard heat-shrink materials are prone to issues like reduced strength and diminished tear resistance in high-temperature environments, potentially leading to insulation failure during long-term operation.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To address the demands of high-temperature operating environments, researchers have employed material modification techniques to enhance the overall performance of heat-shrink tubing. By incorporating ethylene-octene block copolymers (OBC) into the traditional formulation-leveraging their unique molecular structure to improve toughness, heat resistance, and aging resistance-the tubing can maintain more stable mechanical properties under conditions of high temperature and heavy load.

 

Modified heat-shrinkable materials primarily enhance the product's tensile strength and elongation at break by strengthening the bonding between polymer molecular chains. Within the material, the hard-segment structure of the OBC (Olefin Block Copolymer) enhances crystallinity and structural stability at high temperatures, while the soft-segment structure improves flexibility, ensuring good ductility during heat-induced shrinkage and mechanical installation.

 

Experimental studies indicate that increasing the proportion of modified material improves both the tensile strength and elongation at break of the heat-shrinkable tubing. During high-temperature testing, the modified tubing exhibits a significantly reduced decline in mechanical properties, demonstrating superior thermal stability. Furthermore, under conditions of long-term thermo-oxidative aging, the modified material slows polymer degradation, allowing the product to maintain high mechanical reliability.

 

For power busbar insulation applications, heat-shrinkable tubing must not only withstand mechanical stress but also meet stringent electrical performance requirements. Test results show that the incorporation of modified materials does not significantly reduce dielectric breakdown strength, enabling the tubing to continue meeting insulation protection standards for power equipment. Consequently, these materials are suitable for use in electrical connections-such as insulated copper busbars-that require highly reliable insulation protection.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In addition to insulation performance, flame retardancy is a critical metric for protective materials used in power equipment. Abnormal temperature rises can occur during the long-term operation of high-voltage switchgear; therefore, insulation materials must possess effective flame-retardant properties to mitigate fire risks. Limiting Oxygen Index (LOI) and glow-wire tests reveal that the modified heat-shrinkable tubing retains its flame-retardant capabilities while offering enhanced mechanical properties, thereby meeting the standards required for relevant electrical equipment applications.

 

In high-current operating environments, temperature rise characteristics directly impact equipment lifespan and operational safety. Temperature rise testing typically involves simulating actual operating conditions by continuously applying rated current to the conductor and observing the behavior of the insulation material under thermal cycling. During such tests, as high current flows continuously through the conductor, the temperature rises; conventional heat-shrinkable materials may crack due to thermal stress concentration.

 

In contrast, heat-shrinkable tubing formulated with the enhanced modification maintains superior structural integrity at elevated temperatures. Even in the presence of localized defects or mechanical openings, the material maintains excellent crack resistance, effectively mitigating safety risks associated with insulation damage. Such performance is crucial for equipment designed for long-term operation, including high-voltage switchgear, energy storage systems, and power conversion equipment.

 

The advancement of new energy vehicles, energy storage systems, and high-power power electronics has raised the bar for busbar insulation protection. Conventional single-layer insulation methods struggle to meet the combined demands for high current capacity, high-temperature tolerance, and high reliability. Consequently, heat-shrinkable insulation materials must be optimized in tandem with copper busbar structural design, connection methods, and operating environments.

 

In the powertrains of new energy vehicles, battery connection structures must balance high-current transmission, space efficiency, and safety. For instance, a flat copper battery busbar configuration featuring heat-shrink tubing ensures stable electrical conductivity while utilizing the heat-shrink insulation layer to minimize short-circuit risks and enhance overall system safety.

 

For energy storage stations and industrial power equipment, busbars must reliably handle high currents over extended periods, necessitating stable conductivity and dependable insulation. Employing copper busbars with heat-shrink insulation allows for reduced safety clearance requirements between exposed conductors while simultaneously improving internal space utilization.

 

As electrical equipment evolves toward higher voltages and power densities, heat-shrinkable insulation materials will continue to advance in terms of heat resistance, mechanical strength, flame retardancy, and environmental sustainability. Through material modification, structural optimization, and manufacturing process improvements, the long-term operational reliability of power busbar systems can be further enhanced.

 

In practical engineering applications, composite busbar structures-such as flat square copper busbars with PVC heat-shrink tubing-have emerged as vital connection solutions for new energy, power electronics, and industrial control equipment. Combining conductive materials with protective insulation enables more efficient and safer power transmission.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Overall, the development of high-temperature-resistant, reinforced heat-shrinkable tubing for electrical insulation offers a new technical pathway toward the miniaturization and highly reliable operation of high-voltage electrical equipment. By optimizing material formulations to improve heat resistance, tear strength, and insulation performance, manufacturers can effectively address the challenges of busbar insulation in high-temperature environments, thereby providing a stable foundation for the future development of smart grids, new energy vehicles, and energy storage systems.