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Rigid Busbars Reign Supreme in EVs

Posted by Tim Lynch | 6/14/24 10:00 AM

Busbars: The Lifeline of Electric Vehicles

Before we discuss why rigid busbars are superior to flexible busbars, it's crucial to grasp the fundamental role that busbars play in the operation of electric vehicles (EVs). In the world of EVs, each component is essential for achieving top-notch performance, efficiency, and safety. Among these components, busbars act as the backbone of the electrical system, ensuring seamless power flow between components like the battery pack and motor controller.

These conductive bars are tasked with efficiently transmitting high currents while minimizing voltage drop and impedance. They must also endure the rigors of the automotive environment, including mechanical stresses, temperature changes, and vibrations. Furthermore, busbars play a significant role in managing the vehicle's weight, volume, and thermal performance, making their design and implementation key factors in EV engineering.

The debate between rigid and flexible busbars often arises, sparking the question: which option is superior? In this exploration, we delve into the details of both types, shedding light on why rigid busbars stand out as the optimal choice for driving the future of electric mobility.

Understanding the Basics: Rigid vs. Flexible Busbars

Before diving into the comparison, let's grasp the fundamentals of each type.

Rigid Busbars: Rigid busbars are typically constructed from solid metal, such as copper or aluminum, providing robust structural integrity. They maintain a fixed shape and configuration, making them ideal for applications where stability and durability are paramount.

Flexible Busbars: Flexible busbars are crafted from laminated sheets of conductive material, usually copper, with a layer of insulation between them. This design allows for bending and shaping, facilitating versatility in installations where complex configurations are necessary.

Flexible Busbars: The Appeal and Limitations

Flexible busbars have gained popularity in various applications due to their flexibility and ease of installation. In EVs, flexible busbars offer advantages such as:

  • Conformability: Flexible busbars can conform to irregular shapes and contours within the vehicle, enabling efficient use of space and simplifying assembly.
  • Thermal Management: Some flexible busbars incorporate thermally conductive materials in their construction, aiding in heat dissipation and contributing to the overall thermal management of the vehicle.

However, despite these advantages, flexible busbars present several limitations, especially in the context of high-power EV applications:

  • Limited Current Carrying Capacity: The flexibility of these busbars often comes at the cost of reduced current carrying capacity compared to their rigid counterparts. In high-power EVs, where currents can be substantial, this limitation can lead to voltage drops and increased resistive losses.
  • Mechanical Stability: While flexible busbars offer some vibration dampening properties, they may lack the mechanical stability required to withstand the rigorous conditions encountered in automotive environments over the vehicle's lifetime.
  • Complexity in Design and Manufacturing: Designing flexible busbars to meet the specific electrical and mechanical requirements of EVs can be complex, requiring careful consideration of material properties, geometry, and manufacturing processes.

Rigid Busbar Advantages

Solid busbars are widely utilized in the electric vehicle (EV) sector. In EV applications, these rigid busbars boast benefits such as:

  • High Power Handling: Rigid busbars excel in applications where high power is required, such as connecting battery modules, drive units, DC-to-DC converters, and auxiliary loads (e.g., heaters, air compressors).
  • Automated Assembly: Their rigidity makes them ideal for automated assembly processes. Robots can easily position and connect solid busbars.
  • Temperature Resistance: Copper busbars, in particular, withstand high temperatures better than aluminum.
  • Recyclability: Both copper and aluminum are infinitely recyclable, contributing to the circular economy.

When to Choose Rigid Busbars

  • High-Temperature Applications: Efficient heat dissipation is crucial for preventing overheating and maintaining optimal performance in electrical systems. Rigid busbars excel in this aspect, as their solid metal structure facilitates effective heat transfer. This capability ensures that the busbars remain within safe temperature limits even under demanding operating conditions, safeguarding equipment and minimizing the risk of thermal failures.
  • Stability: One of the primary advantages of rigid busbars lies in their structural stability. Their fixed configuration eliminates the risk of deformation or sagging, even under high loads or adverse conditions. This stability reduces the likelihood of electrical faults and ensures uninterrupted power supply, critical in mission-critical applications where reliability is paramount.
  • High-Current Applications: In applications requiring high current densities, such as industrial power distribution and renewable energy systems, rigid busbars reign supreme. Their superior electrical conductivity and mechanical stability make them ideally suited to handle the demanding requirements of such environments, ensuring reliable and efficient power transmission.
  • Enhanced Electrical Conductivity: Rigid busbars, with their solid metal construction, offer superior electrical conductivity compared to their flexible counterparts. This conductivity minimizes power losses during transmission, ensuring optimal efficiency in power distribution systems. Additionally, rigid busbars exhibit lower resistance, enabling them to handle higher current densities without overheating.
  • Longevity and Durability: Rigid busbars boast exceptional longevity and durability, thanks to their solid metal construction. They are inherently resistant to mechanical stress, corrosion, and thermal expansion, prolonging their service life and minimizing maintenance requirements. This durability translates to significant cost savings over the long term, making rigid busbars a sound investment for various industries.

Challenges of Rigid Busbars

  • Manufacturing Tolerances: Extremely rigid busbars may pose challenges during connection due to manufacturing tolerances.
  • Thermal Expansion: Rigid bars are less forgiving when it comes to thermal expansion and contraction.
  • Harsh Environments: Temperature variations can stress rigid busbars.
  • Weight Considerations: Aluminum busbars are lighter than copper, but their larger cross-sections may limit their use when space is scarce.


In the dynamic landscape of electric mobility, the choice between rigid and flexible busbars holds significant implications for the performance, efficiency, and safety of EVs. While flexible busbars offer certain advantages in terms of conformability and vibration dampening, they fall short when it comes to high-power applications where robustness and reliability are paramount.

In contrast, rigid busbars emerge as the clear frontrunner, offering unparalleled current carrying capacity, mechanical strength, and thermal performance. By embracing rigidity in busbar design and implementation, EV manufacturers can ensure the optimal functioning of their vehicles, meeting the demands of the increasingly electrified transportation landscape.

As the world transitions towards a sustainable future powered by electric mobility, the role of rigid busbars as the backbone of EV power systems becomes ever more pronounced. In the quest for innovation and advancement, it's imperative that we recognize and leverage the inherent strengths of rigid busbars to propel the evolution of electric vehicles towards greater performance, efficiency, and reliability.

Remember, whether rigid or flexible, busbars play a critical role in powering our electric future!  Learn more about Kenmode's busbar offering.




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