Analysis Of Busbars in New Energy Vehicle High-Voltage Systems

In the new energy vehicle sector, busbars are essential components in high-voltage and high-current transmission systems. Compared to traditional fuel-powered vehicles, new energy vehicles operate at higher voltages and have greater power densities, placing higher demands on busbars in terms of power distribution, thermal management, and electromagnetic compatibility.

 

This article systematically explains busbar types, advantages, manufacturing, and design key points from an industry perspective. Common technical terms (such as laminated busbars, laminated copper busbars, and laminated copper busbars) are incorporated throughout the article for reference by both engineering designers and procurement professionals.

 

 

 

 

Busbars can be categorized by material: copper and aluminum. Based on flexibility, they can be divided into rigid and flexible busbars. Rigid busbars typically feature solid conductors in rectangular or chamfered rectangular shapes and are suitable for applications where space is limited and a certain degree of rigidity is required.

 

Flexible busbars are constructed by stacking multiple layers of thin, flat copper sheets and coating them with insulating material, offering improved flexibility and stress relief. Laminated busbars (also known as laminated busbars) achieve high-density integration through multiple layers of conductors and insulation. Common forms include laminated copper busbars, laminated copper bars, and laminated flexible busbars.

 

 

Compact Structure and High Space Utilization: Laminated busbars replace numerous cables or thick copper bars with multiple layers, significantly saving space and simplifying assembly.

 

Low Impedance and Excellent Heat Dissipation: Short, large-cross-sectional conductor paths reduce contact resistance and line losses, lowering overall temperature rise and improving system reliability.

 

Low Inductance, High Capacitance: The layout of multiple layers of closely spaced conductors effectively suppresses loop inductance, mitigates voltage spikes, and protects power devices (such as IGBTs and SiC).

 

Easy Automated Assembly and Integration with PCBs and Other Modules: The standardized modular design facilitates rapid assembly and production line automation.

 

Electromagnetic Compatibility and Shielding: The multi-layer design provides partial EMI shielding, reducing system interference.

 

 

Battery Systems: Current distribution and high-voltage power distribution at the cell, module, and pack levels often utilize rigid or laminated busbars to meet high current and low voltage drop requirements.

 

Motor Drives and Power Electronics: To meet high-frequency switching and rapid current switching, the Laminated Bus Bar for Power Electronics is often used to reduce loop inductance and improve thermal performance.

 

Communications and Data Centers: In high-density power supply scenarios, the Laminated Bus Bar for Telecom can be used to achieve modular power distribution and optimize heat dissipation.

 

Customized Solutions: Customized solutions for specific customers or industries (e.g., named application scenarios or reference cases like the Laminated BusBar for Mersen) demonstrate the adaptability of laminated busbars across diverse supply chains.
 

 

 

 

The typical busbar manufacturing process includes: Material Selection → Cutting → Surface Pretreatment (e.g., pickling and cleaning) → Slicing/Punching → Lamination/Alignment → Insulation Coating or Injection Molding → Lamination and Forming → Side Treatment and Trimming → Surface Treatment (Tinning, Nickel Plating, or Passivation) → Final Inspection (Resistance, Voltage Resistance, and Temperature Resistance) → Packaging.

 

For Laminated Copper Busbars and Laminated Flexible Busbars, the choice of interlayer insulation material, temperature/pressure control during the lamination process, and interlayer alignment accuracy are key factors in determining the product's electrical and mechanical performance. Automated feeding, precision punching, and in-line testing (voltage resistance, leakage current, and thermal imaging) are essential for achieving high-yield mass production.

 

 

Current Carrying Capacity and Thermal Simulation: Design the cross-sectional area based on the system's current density requirements, and use thermal simulation to confirm the temperature rise and lifespan under maximum operating conditions. At high current densities, consider enhancing local heat dissipation.

 

Insulation and Creepage Distance: The insulation thickness and creepage/air gap distances are determined based on the system voltage and safety level to ensure a safety margin in the event of a short circuit or insulation breakdown.

 

Mechanical Strength and Vibration Tolerance: Under electric drive and vehicle operating conditions, busbars must meet reliability requirements for shock, vibration, and thermal cycling. Laminated Flexible Busbars offer advantages in stress relief and fatigue resistance.

 

Electromagnetic Compatibility (EMC): Minimize loop area through layer layout and circuit design, and incorporate shielding layers or specialized EMI treatment structures when necessary.

 

Assembly and Testability: Consider the layout of bolt connections, plug-in interfaces, solder joints, and test points to facilitate assembly and maintenance.

 

 

 

 

Busbars are highly dependent on system topology and mechanical constraints, resulting in a low degree of standardization, and are often primarily customized. This requires manufacturers to possess rapid design verification capabilities, experience in material matching, and complete manufacturing capabilities.

 

Despite this, series solutions have gradually been developed for specific applications (such as motor drives and telecommunications power supplies), such as the Motor Drive Laminated Bus Bar for Power Electronics and the Laminated Bus Bar for Telecom, enabling modular production and rapid delivery within a certain range.

 

 

A comprehensive quality assurance system includes material inspection, resistance/continuity testing, voltage withstand testing, thermal cycling and thermal shock testing, vibration and impact testing, and long-term life testing. For mass production of laminated copper bus bars or laminated bus bars, online resistance testing and spot thermal imaging inspections can effectively detect early defects.

 

 

Higher Integration and Smaller Size: As voltage and power density continue to increase, higher requirements are placed on high-density power distribution components such as laminated bus bars.

 

New Materials and Surface Treatment: Developing highly reliable insulating films and corrosion-resistant surface treatment technologies to improve lifespan and process compatibility.

 

Automation and Intelligent Manufacturing: Improving design automation (electrical-thermal-mechanical co-simulation) and production automation to reduce delivery time and costs.

 

Standardization and Modularity: While ensuring performance, we will promote modular product lines for typical applications (such as motor drives, communications, and energy storage), balancing customization and scalability.

 

 

As a key, "invisible" component in the high-voltage system of new energy vehicles, busbars play a crucial role in power transmission, heat dissipation, electromagnetic compatibility, and assembly efficiency. Technologies such as Laminated BusBars, various Laminated Copper BusBars, and Laminated Flexible BusBars provide a viable path to address higher voltages, higher currents, and more stringent space constraints.

 

Looking ahead, by combining system-level simulation, material innovation, and manufacturing automation, busbars will continue to develop towards higher integration, modularization, and high reliability, thereby better serving key subsystems such as power batteries, motor control systems, and power electronics.