The design and selection of high-voltage wiring harnesses and connectors for new energy vehicles

Designers focus on several critical factors when developing automotive high voltage wiring harness systems for new energy vehicles. They address connector and termination issues, manufacturing defects, and environmental stress, which often cause failures such as corroded contacts, loose connections, and wire breaks. Material selection plays a vital role. For example:

Proper design and selection increase vehicle safety, efficiency, and reliability.

Key Takeaways

• High-voltage wiring harnesses must prioritize safety through proper design and material selection to prevent failures.

• Using a dual-rail design enhances reliability by preventing electrical leakage and ensuring continued operation if one rail fails.

• Effective insulation and shielding are crucial for minimizing electromagnetic interference and maintaining system integrity.

• Regular maintenance and accessibility features in wiring harnesses simplify repairs and extend the lifespan of connectors.

• Adhering to industry standards for connectors ensures compatibility, safety, and reliable performance in new energy vehicles.

High-Voltage Wiring Harnesses: Design Principles

 

 

System Architecture and Dual-Rail Design

Automotive engineers prioritize system architecture when designing high-voltage wiring harnesses for new energy vehicles. The dual-rail design stands out as a critical safety feature. This architecture prevents high-voltage circuits from using the vehicle chassis as a return path. By doing so, it eliminates the risk of electrical leakage and potential hazards. Dual-rail systems also introduce redundancy. If one rail fails, the system continues to operate, which enhances reliability and ensures uninterrupted power delivery.

Standardized design practices help manufacturers shorten development cycles and reduce costs. Continuous platforming of materials further improves cost efficiency. Precision in design remains crucial for safety, especially in high-voltage systems. Adhering to rigorous standards ensures vehicle reliability and optimal performance. Engineers must understand these standards to guarantee compliance throughout the development process.

Insulation, Shielding, and EMC Protection

Insulation and shielding form the backbone of safety and electromagnetic compatibility (EMC) in high-voltage wiring harnesses. Engineers select insulation materials with superior electrical properties, such as cross-linked polyolefin and advanced polymers. These materials withstand high voltages and prevent electrical leakage.

Shielding techniques play a vital role in minimizing electromagnetic interference (EMI). Common configurations include shield wire braid layers, combinations of shield wire braid and aluminum foil, and braided mesh or aluminum tubes. Proper grounding of the shield prevents interference from external signals. Engineers avoid multiple grounding points to eliminate potential differences that could induce unwanted interference.

Tip: Selecting connectors with integrated shielding ensures a continuous connection between the cable and the harness, creating a closed loop during crimping and further reducing EMI.

Manufacturers implement braided shielding in wire harnesses to combat strong EMI. This approach, combined with shielded connectors, maintains system integrity and protects sensitive electronic components.

Safety and Cost Considerations

Safety remains the top priority in the design of high-voltage wiring harnesses. Engineers address several risks through thoughtful design strategies. The table below summarizes common safety risks and corresponding mitigation strategies:

Manufacturers balance cost control with safety requirements by minimizing wiring length and weight. They ensure compliance with safety regulations and select high-quality connectors. Dual-track harness designs and effective shielding help mitigate electromagnetic interference while maintaining cost efficiency.

Engineers consider concealment and compliance with collision regulations. They implement protection measures to prevent electric leakage and fires. Proper layout addresses risks to occupants and ensures safe operation. Key factors such as working voltage, working temperature, temperature rise, wire diameter, cable protection, and connector selection guide the design process.

Note: Standardized design and continuous material platforming not only improve safety but also contribute to significant cost savings for manufacturers.

High-Voltage Wiring Harnesses: Layout and Routing

Component Placement and Path Planning

Engineers plan the placement of high-voltage wiring harnesses with precision. They consider the shortest and safest routes between components. This approach reduces energy loss and improves thermal management. Computational fluid dynamics (CFD) helps identify thermal hotspots. Proper routing can lower temperatures by 8 to 12 degrees Celsius. Designers avoid parallel routing of high current and low voltage lines. This practice reduces electromagnetic interference by nearly 75%. Shielding wires and cables protects sensitive electronic systems from disruption.

Note: Electromagnetic interference can disrupt communication systems and sensor networks. Shielding and careful path planning maintain system reliability.

Fixing, Mounting, and Vibration Resistance

Vehicle operation exposes wiring harnesses to constant vibration and movement. Engineers use reliable fixing methods and special brackets to secure harnesses. They design layouts to avoid excessive length or shortness, which minimizes friction and wear. Protective covers shield vulnerable areas from environmental damage. Three-layer conduit systems distribute mechanical stress. Silicone strain relief anchors reduce pullout forces at critical points. These strategies protect connector integrity and prevent wire fatigue, especially in high-frequency environments.

• Proper layout design minimizes vibration friction.

• Special brackets and fixing methods prevent harness movement.

• Protective covers and conduit systems enhance durability.

Maintenance and Accessibility

Designers prioritize maintenance and accessibility in electric vehicle wiring harness systems. They use connectors that ensure proper connections and easy access for service. Organized harness bundling prevents interference and simplifies maintenance. Three-dimensional layouts optimize space and allow for easier repairs. Insulation materials prevent accidental contact with metal parts, enhancing safety. Heat-resistant and waterproof materials ensure stability in extreme conditions. Accessibility features facilitate quick disassembly and assembly during maintenance.

Cable Selection Criteria

Conductor and Insulation Materials

Engineers select conductor and insulation materials based on electrical performance, durability, and cost. Copper remains the preferred conductor due to its excellent conductivity and corrosion resistance. Aluminum offers a lightweight and cost-effective alternative, especially in applications where weight reduction is critical.

XLPE insulation provides outstanding voltage resistance and mechanical strength. Silicone rubber excels in high-temperature environments and offers flexibility for complex routing. These materials ensure that high-voltage wiring harnesses maintain safety and reliability under demanding conditions.

Cross-Section, Voltage Rating, and Heat Resistance

Cable selection depends on several technical criteria:

1. Cable diameter must match the layout and characteristics of high-voltage components.

2. Engineers increase the cross-sectional area to handle higher current and reduce resistive losses.

3. Voltage rating ensures the cable can withstand the electrical load without failure.

4. Heat resistance maintains insulation integrity during high current transmission.

Larger cross-sectional areas help mitigate the higher resistivity of aluminum but may complicate installation due to increased size. Proper voltage ratings and heat resistance prevent insulation breakdown and cable failure, especially in electric vehicles that operate under variable loads.

Tip: Always verify that cables meet industry safety standards, such as low-smoke halogen-free requirements, to enhance fire safety and environmental protection.

Shielding and Sheath Materials

Shielding and sheath materials protect cables from electromagnetic interference and harsh environments. Engineers use advanced materials to ensure both safety and durability.

Halogen-free flame retardant (HFFR) compounds offer excellent flame resistance and environmental safety. Recyclable thermoplastic elastomers (TPEs) provide flexibility and thermal performance while supporting sustainability goals. These advancements help manufacturers meet strict safety and environmental standards.

Connector Selection and Standards

 

 

Connector Types and Performance Requirements

Automotive engineers select high voltage automotive connectors based on rigorous performance criteria to ensure the reliability of high-voltage wiring harnesses. The most common connector types include LV (Low Voltage) standard connectors, USCAR connectors, and JIS connectors. Each type meets specific industry standards for compatibility and safety.

Connectors must deliver consistent electrical, mechanical, and environmental performance. The following table summarizes the essential requirements:

Engineers prioritize connectors that maintain stable contact pressure and minimize resistance. They select materials that resist corrosion and environmental degradation. Advanced manufacturing techniques ensure precision and durability, reducing the risk of electrical contact failure and insulation breakdown.

Tip: Selecting connectors with robust locking mechanisms and high IP ratings enhances both safety and longevity in electric vehicle applications.

Mechanical, Electrical, and Environmental Standards

High-voltage connectors must comply with stringent mechanical, electrical, and environmental standards. These standards protect users and ensure reliable operation under demanding conditions.

Manufacturers adhere to safety standards that prevent electric shock and guarantee user protection. Performance standards verify that connectors function reliably in diverse environments. Design requirements established by leading automotive manufacturers ensure compatibility and safety across vehicle platforms.

Engineers recognize that the quality of high-voltage connectors directly affects electrical performance. Manufacturing precision influences mechanical reliability. Environmental performance remains critical for safe operation on the road.

• High-voltage connectors must meet high quality and manufacturing precision standards.

• These connectors are considered high-end products due to their critical role in vehicle safety.

Manufacturers implement rigorous testing protocols to verify connector reliability. They analyze failure modes such as poor contact, insulation breakdown, and mechanical connection issues. Advanced diagnostic tools, like topology diagnostics software, help identify and prioritize connector faults, streamlining maintenance and reducing downtime.

Safety Features and Serviceability

Safety features in high-voltage connectors protect both users and vehicle systems. Engineers integrate High-Voltage Interlock Loop (HVIL) technology to safeguard individuals during assembly, repair, and operation. HVIL acts as a circuit breaker, alerting drivers if a high-voltage connection is compromised. The system monitors connectors with a low-voltage loop, indicating issues if the signal is interrupted.

• HVIL ensures the system cannot be powered on if the circuit is incomplete, enhancing safety.

• Finger-proof and touch-safe disconnection technologies prevent accidental contact with high-voltage components.

• Fuse-in connectors disconnect the battery during current spikes, preventing catastrophic events.

Serviceability remains a key consideration in connector design. Field-replaceable pins minimize downtime and enhance productivity by allowing on-site service. Connectors with long lifespans, up to 50,000 cycles, reduce total cost of ownership. Ergonomic designs facilitate easy one-hand operation, lowering the risk of repetitive motion injuries. Quick connections can be made without additional tools, improving efficiency during maintenance.

Engineers address common failure modes such as electrical contact failure, insulation breakdown, contamination, arcing, and physical damage. They select materials that resist corrosion and environmental degradation. Careful design considerations enhance connector robustness, while rigorous testing protocols ensure reliability and safety.

Note: Proper testing and handling of high-voltage wiring harnesses and connectors are crucial to avoid failures during operation. Advanced diagnostic methods and careful material selection help maintain system integrity and vehicle safety.

Automotive engineers achieve optimal safety and reliability by following industry best practices for high-voltage wiring harnesses and connectors. They identify electrical requirements, create detailed schematics, and use CAD modeling for precise routing. Adherence to international standards mitigates risks such as short circuits and electromagnetic interference. The following checklist highlights essential design steps:

Applying these principles enhances vehicle performance, safety, and compliance with industry standards. 

FAQ

What standards guide the selection of high-voltage connectors in new energy vehicles?

Automotive engineers follow standards such as USCAR, JIS, and LV. These standards ensure compatibility, safety, and reliability. They specify requirements for voltage, current, mechanical durability, and environmental resistance.

How do engineers ensure the safety of high-voltage wiring harnesses?

They use insulation materials with high voltage resistance. They implement shielding to reduce electromagnetic interference. Safety features like HVIL and robust locking mechanisms prevent accidental contact and disconnection.

Why do manufacturers prefer copper over aluminum for conductors?

Copper offers superior conductivity and corrosion resistance. It supports stable power delivery and reduces energy loss. Aluminum provides a lightweight alternative but requires a larger cross-section for the same performance.

What maintenance practices extend the lifespan of connectors and harnesses?

Regular inspections detect wear, corrosion, or loose connections early. Engineers recommend cleaning contacts, checking seals, and replacing damaged components. Proper maintenance ensures reliable operation and reduces the risk of failure.