The Engineering Value of Braided Sleeving in New Energy Vehicles (NEV)

As the architecture of new energy vehicles (NEVs) evolves toward higher voltage, lightweight construction, and greater system integration, the reliability and safety of wiring harnesses have become a critical engineering focus. Acting as the “neural network” of the vehicle, harness systems require comprehensive protection against mechanical, electrical, and thermal challenges.


Within this context, braided sleeving has evolved from a simple harness organizer into a system-level protective component that directly impacts electrical safety, EMC performance, and long-term durability.




1.Key Application Areas — Where & Why

In NEVs, braided sleeving is deployed across multiple key harness zones, each with specific engineering objectives:

  • High-Voltage Harness (Battery ↔ Inverter / Motor / DC-DC)
Provides mechanical protection, insulation cut-through resistance, and, when required, electromagnetic shielding. Maintains thermal stability and fire resistance to ensure HV system safety.
  • Battery Module and Pack Internal Harnesses
Prevents insulation wear caused by vibration or friction. Expandable or split-sleeve designs allow easy maintenance and module replacement.
  • On-Board and External Charging Cables
Must be abrasion-resistant, UV- and oil-resistant, while maintaining flexibility for user handling and storage.
  • Power Electronics and Motor Bay (Inverter, PDU, DC-DC)
Requires high-temperature-resistant, flame-retardant, and optional shielding sleeving for reliable performance near heat sources.
  • Body Control and Signal Harness (CAN / LIN / Sensor)
Ensures cable organization, EMC separation, and visual identification, supporting efficient vehicle assembly and serviceability.


2. Common Challenges & Engineering Responses

Wiring harnesses in NEVs face unique stresses such as high voltage, EMI interference, thermal aging, vibration, and maintenance complexity. Braided sleeving provides practical engineering countermeasures:

Challenge Engineering Response
High Voltage / EMI Risk Use conductive or tinned copper wire braided shields with proper grounding and terminal treatment.
Thermal Cycling & High-Temperature Aging Select high-temperature materials such as fiberglass, PTFE, or aramid blends; apply thermal insulation where needed.
Vibration & Mechanical Abrasion Employ dense or dual-layer constructions (outer abrasion-resistant layer + inner warning color).
Assembly & Maintenance Efficiency Use side-entry or zipper-style sleeves to reduce disassembly and rework time.
Compliance & Certification Ensure materials meet UL94, IEC 60332, RoHS, and REACH standards.


3. Material & Structural Trade-offs

Choosing the right material and structure helps balance cost, protection, and assembly efficiency:

  • PET (Polyester) Braided Sleeve — Lightweight, abrasion-resistant, cost-effective, recyclable; ideal for low-heat areas.
  • Fiberglass Sleeve — Excellent thermal resistance (up to 250°C short-term) and flame retardancy.
  • Aramid / Kevlar® Reinforced Sleeve — Exceptional cut and tensile strength; ideal for critical high-protection zones.
  • PTFE / Fluoropolymer Sleeve — Superior chemical and thermal resistance, low friction coefficient.
  • Metallic / Tinned Copper Braid — Provides EMI shielding; requires proper grounding to ensure effectiveness.

Structural Options:
  • Full Braided for continuous protection.
  • Split or Side-Entry for easy installation and service.
  • Dual-Layer for extreme abrasion zones.
  • Self-Closing or Zipper Type for quick assembly and rework.



4. Design & Engineering Checklist


To achieve high reliability in NEV applications, the following parameters should be incorporated into the design phase:

  1. Functional Segmentation: Classify each harness by function (HV Power, LV Signal, Communication, Sensor).
  2. Temperature Rating: Define continuous and peak operating temperatures.
  3. Mechanical Protection: Specify abrasion, cut-through, and bending endurance requirements.
  4. EMC Requirements: Determine shielding coverage, grounding method, and connection design.
  5. Assembly Constraints: Evaluate space, process method (manual or automated), and maintenance needs.
  6. Aesthetics & Identification: Apply colors, stripes, or printing for traceability.
  7. Regulatory Compliance: Confirm material certification (UL94, IEC 60332, RoHS, REACH, ISO 26262).
  8. Maintenance Strategy: Consider modular designs for easy section replacement.



5. Validation & Testing Matrix

To ensure real-world reliability, validation testing should be included during prototype and PPAP stages:

  • Thermal cycling and aging (LV124 / ISO 16750)
  • Vibration and mechanical fatigue testing
  • Flexural fatigue and bending endurance
  • Abrasion and cut-through resistance
  • Flammability and smoke density (UL94, IEC 60332)
  • Salt spray and chemical resistance
  • EMC shielding effectiveness
  • Post-aging insulation integrity



6. Typical Engineering Scenarios

Scenario A: 800V High-Voltage Main Loop
Recommended configuration: outer PET or aramid abrasion-resistant layer + inner fiberglass thermal layer + local tinned copper shield braid with grounded terminals.
Validation focus: grounding continuity, short-circuit tolerance, thermal durability.

Scenario B: Battery Module Interconnect Harness
Recommended configuration: split-type fiberglass or aramid sleeve with visible warning color for maintenance visibility and easy replacement.

7. Actionable Guidelines for OEMs / Tier-1 Suppliers

  1. Define a "Sleeving Grade Matrix" based on harness function (HV, LV, Signal, Charging).
  2. Include test items in the supplier specifications (SOQ / PPAP) and require material certificates.
  3. Validate early during prototype phase to catch assembly or EMC issues.
  4. Standardize assembly tools and processes, such as crimping and grounding methods.
  5. Adopt modular maintenance designs for battery and power electronics harness sections.

8. Conclusion: From a "Finishing Part" to a "System Protector"

In NEVs, braided sleeving has evolved far beyond aesthetics or cable organization. It now serves as a critical protection system safeguarding electrical safety, electromagnetic compatibility, thermal stability, and long-term durability.

With advanced material engineering, structural innovation, and strict validation,MJ provides comprehensive braided sleeving solutions that help global OEMs and Tier-1 suppliers achieve higher reliability, easier maintenance, and improved overall system safety.