Key Technologies for Power Density Improvement: Analysis of Laminated Busbar Industry Knowledge

With the rapid development of new energy vehicles, energy storage systems, industrial converters, and high-frequency power electronic equipment, traditional copper busbar structures can no longer meet the demands for high power density, miniaturization, and low loss. Against this backdrop, laminated busbars have gradually become an important component of modern power connection systems. As an integrated conductive connection solution, it achieves low parasitic inductance, high current carrying capacity, and excellent electromagnetic compatibility through the composite lamination of multiple conductors and insulating materials, and is widely used in high-frequency, high-voltage, and high-power scenarios.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Laminated busbars are essentially multi-layer composite structure connection bars, typically formed by alternating layers of copper or aluminum conductors and insulating media. Compared to traditional discrete copper busbar structures, they can achieve a more rational current path design within a limited space, thereby improving the overall system efficiency and stability. Modern power electronic systems have increasingly higher requirements for low inductance, high-speed switching, and thermal management; therefore, laminated low-inductance busbars have become an important choice for high-performance converter equipment.

 

Structurally, laminated busbars can be designed as double-layer, triple-layer, or even multi-layer structures to meet specific application requirements. Three-layer laminated busbars are particularly widely used in new energy inverters and energy storage PCS systems. By tightly stacking the positive and negative electrodes, the loop area is effectively reduced, allowing the magnetic fields to cancel each other out, thus significantly reducing parasitic inductance. Compared to traditional copper busbar systems, the inductance can be reduced to about one-tenth of the original solution, which is crucial for the stable operation of high-frequency SiC devices and IGBT modules.

 

In high-power electronic systems, switching devices are prone to voltage spikes and EMI interference when operating at high speeds. The application of laminated busbars in high-power converters can effectively mitigate this problem. Due to the extremely small distance between the conductor layers, the magnetic fields generated by the loop currents can cancel each other out, thereby reducing radiated noise and switching losses. This low-inductance characteristic not only improves system reliability but also helps reduce the size of filters and heat sinks, further increasing the power density of the equipment.

 

With the large-scale application of silicon carbide devices, the demand for customized laminated busbars for IGBTs and IGBT laminated busbars continues to grow. IGBT modules have extremely high requirements for uniform current distribution and low-inductance connections, and laminated structures can optimize current paths and reduce local hotspots. For three-level topologies, laminated busbars for three-level inverters can effectively improve midpoint voltage fluctuations and enhance system dynamic response, making them valuable in new energy inverters and industrial frequency converters.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The new energy vehicle industry is one of the fastest-growing sectors for laminated busbar technology. Laminated busbars for electric cars are widely used in electric drive systems, battery packs, OBCs, and DC/DC modules. Compared to traditional wiring harness connections, they reduce installation space, improve conductivity, and reduce overall vehicle weight. With high-voltage platforms gradually moving towards 800V and even higher voltages, High Voltage Explosion-Proof Inverter Busbars face higher requirements for insulation performance, withstand voltage, and thermal stability; laminated structures better meet these complex operating conditions.

 

In the fields of energy storage and power supply (Uninterruptible Power Supply), System Busbars and laminated structures are also widely used. UPS systems have extremely high requirements for power supply stability and low-loss performance. Laminated busbars can reduce system temperature rise, improve energy transmission efficiency, and enhance the long-term operational reliability of equipment. Furthermore, in communication equipment, laminated busbars for telecom power distribution and laminated busbars for internet router backplanes are gradually replacing traditional cable connection solutions to meet the space requirements of high-density cabinets.

 

The rail transit sector is also an important application area for laminated busbars. Subway laminated busbars and composite busbars for train power supply, four-quadrant power modules are widely used in train traction power supply systems and four-quadrant converter modules. Because rail transit systems operate under high vibration, high current, and complex electromagnetic environments, the stability requirements for the connection system are extremely high. Laminated busbars not only improve vibration resistance but also reduce system EMC risks and enhance overall power supply reliability.

 

Besides industrial and new energy fields, laminated busbars are also increasingly being used in high-end fields such as medical equipment, stage lighting, and data centers. For example, laminated bus bars for medical imaging testing devices meet the low noise and high stability requirements of medical imaging equipment; laminated bus bars for rack-mount power distribution are suitable for high-density server rack power supply systems; and laminated bus bars for PDA assembly (a hit-in-stage lighting system) are beginning to be used in high-frequency power supply modules for stage lighting equipment.

 

From a manufacturing perspective, laminated bus bars are typically manufactured using processes such as vacuum hot pressing, lamination bonding, or molding. Insulation materials often use high-insulation materials such as polyimide, PET, and epoxy resin to ensure voltage resistance and thermal stability during long-term operation. For complex spatial layouts, partially laminated bus bars can utilize a laminated structure in localized areas, balancing installation flexibility with low inductance performance, making them suitable for special scenarios such as laminated busbars for complex busbar installations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

During the design process, engineers typically optimize the design by considering current capacity, temperature rise requirements, insulation distance, and EMC performance. A well-planned conductor layout not only reduces system losses but also improves heat dissipation efficiency. Because laminated busbars combine conductivity and structural support, they are classified as laminated busbars, passive electronic components, and play an increasingly important role in modern, highly integrated power systems.

 

Overall, laminated busbar technology is driving the development of power electronic devices towards higher power density, lower losses, and smaller size. With the continuous upgrading of new energy, energy storage, rail transportation, and high-end manufacturing industries, laminated busbars will play an even more crucial role in future high-voltage, high-frequency, and highly integrated power systems, gradually becoming a fundamental component for modern power transmission and power connection.