Busbar Connectors: Ensuring Voltage Stability in Lithium Battery Systems

04/14 Silin Wu

In new energy vehicles and energy storage systems, lithium batteries play a key role in storing and delivering energy. Their performance directly affects driving range and overall system stability. Among the many performance factors, voltage consistency is critical to ensuring efficiency, safety, and long-term reliability. Voltage imbalance can cause uneven charging and discharging, faster battery degradation, and even thermal runaway.

With years of experience in busbar R&D and manufacturing, RHI Electric offers customized busbar connection solutions that help maintain voltage stability across lithium battery systems.


Challenges and Impacts of Voltage Inconsistency

Voltage inconsistencies are often caused by inherent differences among battery cells, including:

  • Capacity mismatch due to production tolerances

  • Internal resistance variations between cells

  • Thermal gradients caused by uneven temperature distribution

  • SOC (State of Charge) deviation during charge/discharge cycles

RHI-Offering Copper & Aluminum Busbar Connection Solutions

These inconsistencies can lead to:

  • Increased risk of overcharge or over-discharge, complicating BMS control

  • Accelerated aging of certain cells, reducing cycle life

  • Reduced system efficiency due to uneven energy utilization

  • Elevated risk of thermal runaway, threatening system safety

Addressing voltage inconsistency at the connection level is crucial to improving the reliability and safety of lithium battery systems.


RHI Custom Busbar Solutions for Enhanced Voltage Consistency

Aluminum Busbars: Lightweight and Performance-Oriented

  • High conductivity with low voltage drop, ideal for high-current applications

  • Corrosion resistance in humid, acidic, or alkaline environments

  • Flexible structural design supports 3D bending and precision stamping to optimize current distribution

RHI-Offering Copper & Aluminum Busbar Connection Solutions

CCS Copper Flat Busbars: Key to Current Equalization

  • Good conductivity to balance current across cells and minimize voltage deviation

  • Excellent fatigue resistance under long-term vibration and thermal cycling, ensuring stable connections

RHI-Offering Copper & Aluminum Busbar Connection Solutions

Custom Copper Busbars: Reliable Backbone for High-Power Systems

  • Exceptional current-carrying capacity for rapid energy transfer

  • High mechanical strength, resistant to deformation under thermal and mechanical stress

  • Surface plating options (nickel, tin) for enhanced corrosion resistance and extended lifespan

  • Multiple insulation solutions including PVC dip-coating, powder coating, and heat shrink tubing to meet high-voltage safety standards


The Role of Customization in Supporting Voltage Consistency

Structural Optimization for Complex Module Integration

  • 3D bending, laser welding, and automated stamping allow for tailored shapes that align with battery pack configurations

  • Integrated high-voltage and low-voltage designs enhance space utilization and wiring efficiency

RHI-Offering Copper & Aluminum Busbar Connection Solutions

Advanced Materials for Balanced Performance

  • Copper-aluminum composite busbars offer an ideal mix of conductivity and lightweight benefits

  • Surface treatments like nickel, tin, or silver plating reduce contact resistance and prevent electrochemical corrosion

Advanced Welding and Insulation for Connection Reliability

  • Laser welding and polymer diffusion welding deliver robust, low-resistance joints

  • Combined with high-temperature insulation materials (ceramic or mica-based), RHI offers busbars capable of withstanding 1000°C open flame for 10 minutes and 3500V DC insulation voltage, ensuring safety in extreme conditions

Polymer Welding Process

Application Value in EVs and Energy Storage Systems

In electric vehicles, busbars play a critical role in connecting battery modules, inverters, DC/DC converters, and motor controllers. With the right materials, structure, and processing, RHI busbars help:

  • Minimize voltage deviations

  • Reduce the risk of thermal runaway

  • Improve energy conversion efficiency

  • Extend system lifespan

  • Enhance overall safety and performance of the vehicle or energy storage system