As a core component of new energy vehicle electrical systems, new energy wiring harnesses must be designed to achieve a precise balance between flexibility and long-term bending fatigue resistance. This challenge stems from the high-frequency vibration, compact layout, and extreme temperature environments experienced by new energy vehicles, requiring the wiring harness to maintain structural integrity and electrical stability during repeated flexing.
The choice of conductor material is fundamental to harness flexibility. New energy wiring harnesses typically utilize a twisted structure of multiple ultra-fine oxygen-free copper wires, with individual wire diameters ranging from 0.08mm to 0.2mm. This design disperses the current path, reducing resistive heating. The annealing process enhances ductility, ensuring uniform deformation during bending rather than concentrated stress. For example, an automaker's charging cable harness for charging stations has achieved an improved flex life of over 5 million cycles by optimizing the twist pitch, significantly exceeding the performance of traditional single-strand copper wire.
Innovative materials for the insulation and sheath layers are key to improving fatigue resistance. Thermoplastic elastomers (TPEs) and silicone rubber are popular choices due to their wide operating temperature range of -60°C to 180°C. Silicone rubber utilizes dynamic molecular chain cross-linking technology to automatically repair microcracks during bending, addressing the low-temperature brittleness and high-temperature melting issues of traditional PVC materials. The sheath layer utilizes polyurethane (PUR) or specialized TPU materials, laser-engraved to achieve UV and abrasion resistance, creating an all-weather protective barrier.
The shielding layer design must balance electromagnetic protection with mechanical flexibility. New energy wiring harnesses typically utilize a dual structure of tinned copper braid and aluminum foil wrap. This structure suppresses high-frequency interference (EMI attenuation >60dB) while maintaining flexible bending. For example, motor controller power harnesses utilize optimized braid angles and aluminum foil thickness to ensure shielding does not break during repeated 180° bends, ensuring zero signal transmission errors.
Optimizing the filler layer structure is key to extending harness life. Traditional filling materials can easily cause frictional wear between the conductor and the sheath. However, a combination of a new silicone foam (density 0.3g/cm³, rebound rate >90%) and aramid fiber bundles (tensile strength 500MPa) can reduce wear by 70% and adapt to temperature changes. A photovoltaic power station's wiring harness, using a three-layer silicone filler with a density gradient design, has reduced its failure rate from 8% to 0.5%, achieving a lifespan exceeding 10 years.
The reliability of connectors and terminals directly impacts the overall performance of the wiring harness. Imported precision crimping machines, paired with genuine German dies, achieve six-sided, circumferential crimping of terminals and copper wires, with a pull-off force that exceeds industry standards by 30%. For high-current circuits, ultrasonic welding technology reduces weld resistance by an order of magnitude through molecular-level fusion and has passed high- and low-temperature cycling tests from -40°C to 150°C, completely eliminating the risk of cold solder joints.
Dynamic simulation and experimental verification are key tools for design optimization. IPS software, based on Koselow's elastic rod theory, simulates the repeated bending of the wiring harness driven by the mobile terminal clip, accurately calculating the minimum bend radius and pull-out force. Combined with Fe-Safe fatigue analysis software, engineers can predict the life distribution of wiring harnesses under multi-axial stress, guiding structural adjustments. For example, simulation optimization of a robotic wiring harness increased the S-bend life from 5,000 to 8,000 cycles.
New energy wiring harnesses will evolve towards intelligent and environmentally friendly features. Built-in fiber optic sensing technology monitors stress distribution in real time, providing early warning of fatigue risks. The development of biodegradable PLA foam and carbon fiber composite tensile layers improves performance while reducing environmental impact. These innovations will continue to drive breakthroughs in the flexibility and fatigue resistance of new energy wiring harnesses, providing a solid foundation for the reliable operation of new energy vehicles.
