Right Battery Choice, Proper Busbar Matching

Right Battery Selection, Proper Busbar Matching — Unlocking the Full Performance of New Energy Batteries

Amid the rapid iteration of the new energy vehicle (NEV) industry, battery selection directly defines a vehicle's core competitiveness. As the "power arteries" of the battery system, busbars play a critical role in determining how effectively battery performance, safety, and service life can be realized.

In today's market, dominated by ternary lithium batteries and lithium iron phosphate (LFP) batteries, selecting the appropriate battery chemistry is only the first step. Precisely matching the corresponding busbar solution is essential to fully unleash overall vehicle performance.

The Dual-Market Landscape: Core Logic of NEV Battery Selection

Ternary lithium batteries and LFP batteries together account for over 95% of the NEV market. Their distinct characteristics define mainstream battery selection strategies, each aligned with specific vehicle positioning and application scenarios.

1. Ternary Lithium Batteries: Long Range & High Performance

Ternary lithium batteries are mainly based on NCM (Nickel Cobalt Manganese) and NCA (Nickel Cobalt Aluminum) chemistries. Their primary advantage lies in high energy density. Current mass-production systems typically achieve 200–300 Wh/kg, enabling longer driving range under the same volume or weight and reliably supporting 500 km+ long-range requirements.

Low-temperature performance is another strength. At –20 °C, ternary lithium batteries can retain 70–80% of capacity, making them well-suited for cold-climate regions and high-end performance vehicles.

However, the use of cobalt and nickel in cathode materials results in higher material costs. Thermal stability is also relatively weaker, with thermal runaway temperatures around 200 °C, placing stricter demands on battery thermal management systems.
Representative applications include Tesla Model S (Long Range / Performance), NIO ET5, BMW iX3, and other premium long-range models. Due to their high power output capability, ternary batteries are also widely adopted in 800 V high-voltage fast-charging platforms.

2. Lithium Iron Phosphate Batteries: Safety & Cost Efficiency

Lithium iron phosphate (LFP) batteries stand out for their high safety, long cycle life, and cost advantages. Free of cobalt, their raw material costs are approximately 30% lower than those of ternary lithium batteries. With standard 1C charge/discharge, cycle life commonly exceeds 3,500 cycles, significantly outperforming conventional ternary batteries.

Through structural innovations such as BYD Blade Battery and CATL CTP (Cell-to-Pack) technology, LFP batteries have substantially improved volumetric efficiency. Mainstream mass-production energy density has reached 160–200 Wh/kg, narrowing the historical gap with ternary batteries.

LFP batteries are best suited for short- to mid-range vehicles, cost-sensitive passenger cars, and markets with moderate ambient temperatures. Their low-temperature performance is relatively weaker, with capacity retention of 40–55% at –20 °C, but this remains sufficient for daily urban commuting.
Typical models include BYD Yuan PLUS, Han, Seal, Tesla Model 3/Y Standard Range, and Wuling Hongguang MINIEV, covering the mainstream economy and family vehicle segments.

3. Industry Trends: Technology Iteration Blurs Application Boundaries

Continuous technological advancement is gradually blurring the boundaries between the two battery chemistries.
Ternary lithium batteries are improving safety and cost control through low-cobalt or cobalt-free formulations and cathode surface coating technologies, while LFP batteries further enhance volumetric energy density via CTP (Cell-to-Pack) and CTC (Cell-to-Chassis) architectures.

Leading OEMs such as Tesla and XPeng now offer both battery options across their product lines to precisely address diverse range and cost requirements. Industry data indicates that by 2025, LFP batteries will account for approximately 55% of the market, while ternary lithium batteries will represent around 40%, maintaining a dual-dominant structure.

Precision Matching: Busbar Solutions for Different Battery Chemistries

Battery characteristics define busbar design requirements, while busbar performance directly enables optimal battery operation. Based on the fundamental differences between ternary lithium and LFP batteries, RHI develops targeted busbar solutions that achieve precise matching and performance synergy.

1. Ternary Batteries: Low Impedance & High-Voltage Performance

Ternary lithium batteries emphasize fast charging and long driving range. Correspondingly, busbars must deliver low electrical resistance, excellent low-temperature performance, high-voltage insulation, and the ability to withstand high peak currents, minimizing energy loss while ensuring high-voltage safety.

Key Technical Requirements

• DC resistance ≤ 0.5 mΩ (25 °C, DC test)

• Operating temperature range: –40 °C to +85 °C

• Compliance with 800 V high-voltage insulation standards

• Creepage distance ≥ 12 mm (UL-based)

• Capability to withstand instantaneous currents above 2,000 A

RHI Solution

• T2 oxygen-free copper busbars with nickel plating ≥ 3 µm to reduce contact resistance and oxidation

• Customized UL94 V-0 flame-retardant insulation systems for high-voltage safety

• Low-impedance, high-thermal-conductivity rigid copper busbars for high-temperature zones, enabling efficient collaboration with BMS and thermal management systems

• Copper foil flexible connectors inside sealed battery packs, utilizing higher thermal mass to absorb transient heat and delay peak temperature rise, enhancing thermal stability

2. LFP Batteries: Lightweight & Cost-Optimized Design

LFP batteries prioritize high current discharge capability, long cycle life, and cost efficiency. Busbar solutions must balance current-carrying capacity, long-term mechanical stability, and economic performance while accommodating structural design characteristics.

Key Technical Requirements

• Current density of 5–8 A/mm²

• Excellent anti-creep performance, with deformation < 0.1% under long-term load at 85 °C

• Optimized lightweight structure without compromising electrical performance

RHI Solution

• Copper–aluminum transition busbars using atomic diffusion welding or friction welding, combined with cross-sectional optimization, achieving up to 30% cost reduction compared to pure copper busbars

• Anti-creep copper alloys for improved long-term stability

• Lightweight aluminum busbars for auxiliary circuits, reducing weight by approximately 40% compared to copper while meeting performance requirements

Application Scenarios

• Rigid copper busbars for fixed connections such as module series/parallel links and main power circuits

• Copper foil flexible connectors at module-to-housing interfaces to absorb vibration and thermal expansion, with enhanced surface area for natural heat dissipation

Busbar Selection Guide: Scenario-Oriented Matching

Beyond battery chemistry, busbar selection must consider installation position and operating conditions to maximize system reliability and performance.

• Rigid Copper Busbars
  Ideal for module interconnections, main positive/negative outputs, contactor connections, and inverter DC-link applications. These areas demand ultra-low impedance and high mechanical stability, with heat efficiently dissipated via enclosures or cooling systems.

• Copper / Aluminum Foil Flexible Connectors
  Suitable for cell interconnections within modules and interfaces subject to vibration, assembly tolerances, or thermal expansion. Their flexibility mitigates mechanical stress, while large surface area enhances heat dissipation and prevents localized overheating.

• Aluminum Busbars
  Optimal for auxiliary power circuits, BMS power and signal connections, and CCS module interconnections. Particularly effective in weight-sensitive micro EVs or large-scale energy storage systems, delivering substantial cost and weight reductions without sacrificing functionality.

Conclusion

Battery selection defines vehicle positioning, while proper busbar matching ensures battery performance is fully realized. Whether addressing the fast-charging and long-range demands of ternary lithium batteries or the safety and cost efficiency of LFP batteries, professional busbar solutions are indispensable.

With deep expertise in new energy busbar technologies, RHI delivers end-to-end customized solutions—from material selection and structural design to process optimization—fully aligned with diverse battery systems and vehicle requirements.
Choose the right battery, and match it with the right busbar.
Contact us to unlock the optimal solution for new energy battery interconnection.