New energy cable (For photovoltaic, wind power, new energy vehicles and other scenarios, the production process optimization should meet the requirements of high and low temperature resistance, weather resistance, oil resistance, high insulation and other characteristics) Material adaptation, precision control, efficiency improvement and quality stability The four core objectives, combined with its special performance requirements (such as resistance to 200 ℃ high temperature and UV aging), are targeted for improvement. The specific optimization path is as follows: The core materials (conductor, insulation layer, sheath layer) of new energy cables need to be pretreated to improve performance and reduce subsequent processing defects:
Conductor pretreatment: improve conductivity and processability
use Continuous annealing process : Conduct online annealing for copper conductor (or aluminum alloy conductor) (temperature 400-500 ℃, nitrogen protection and oxidation prevention), eliminate processing stress, reduce conductor resistance (copper conductor resistivity ≤ 0.0172 Ω・ mm ²/m), and enhance flexibility (bending radius can be reduced to 6 times of diameter to meet the wiring requirements of new energy vehicles).
Conductor surface cleaning: through Ultrasonic cleaning+hot air drying Instead of traditional wiping, the oil stain and oxide layer on the surface are completely removed (residual oil stain will lead to the reduction of the adhesion of the insulation layer). After cleaning, the surface roughness of the conductor Ra ≤ 0.8 μ m, to ensure close connection with the insulation layer.
Modification and mixing optimization of insulation/sheath materials
Common materials for new energy cables (such as cross-linked polyethylene XLPE, silicone rubber, fluoroplastics) need to be mixed to improve uniformity:
Formula accurate measurement : Adopted Weight loss feeder (precision ± 0.1%), add base materials (such as XLPE), cross-linking agents (such as DCP), anti-aging agents (such as carbon black, antioxidant) in proportion to avoid the proportion deviation caused by manual ingredients (such as insufficient antioxidant will reduce the weather resistance).
Twin screw mixing optimization : Control the screw speed (300-500r/min) and temperature (such as XLPE mixing temperature 120-150 ℃) to ensure that the additives are evenly dispersed (such as carbon black dispersion reaching above grade 9 to avoid the risk of local conductivity). At the same time, remove the bubbles generated in the mixing by vacuuming (vacuum degree ≤ -0.08MPa) (bubbles will lead to insulation breakdown).
Extrusion is a key process for forming cable insulation layer and sheath layer Thin wall, high-precision Optimization required:
Multi layer co extrusion technology: improve efficiency and adhesion
use Three layer co extrusion unit (conductor shielding layer+insulation layer+insulation shielding layer), realize synchronous extrusion through precision die (concentricity error ≤ 0.05mm), avoid interlayer pollution caused by traditional step-by-step extrusion (such as breakdown caused by impurities), and increase the production speed by more than 30% (from 15m/min to 20-25m/min).
For the high-voltage cables of new energy vehicles (such as 800V system), * * "semi conductive layer+cross-linked insulation layer+oil resistant sheath" co extrusion * * is adopted. Through the temperature gradient control of the die head (semi conductive layer 180-200 ℃, insulation layer 200-220 ℃), interlayer fusion bonding (peel strength ≥ 1.2N/mm) is ensured to avoid delamination.
Accurate control of temperature and pressure
Extrusion of insulation layer (such as XLPE): the temperature of the barrel is controlled in sections (feeding section 140-160 ℃, melting section 180-200 ℃, die head 200-220 ℃), and the temperature fluctuation of each section is controlled within ± 1 ℃ through the PID closed-loop system (excessive temperature fluctuation will lead to uneven thickness of the insulation layer); The die head pressure shall be stabilized at 15-25MPa (pressure fluctuation ≤ ± 0.5MPa) to avoid the bamboo shaped appearance due to sudden pressure change.
Fluoroplastics (such as FEP) extrusion: Screw barrel nitriding treatment (surface hardness ≥ 900HV), reduce friction heat generated by material viscosity, and control extrusion temperature (350-400 ℃) to avoid high-temperature degradation (degradation will produce bubbles, affecting insulation performance).
Online thickness monitoring and feedback adjustment
equipment Laser caliper+X-ray thickness gauge : Real time monitoring of the outer diameter (precision ± 0.01mm) and wall thickness of the insulation layer/sheath layer (for example, the thickness of the cable insulation layer of new energy vehicles is required to be 1.0 ± 0.05mm), data feedback to the extruder control system, and automatic adjustment of screw speed or traction speed (adjustment response time ≤ 0.5s) to ensure that the size deviation is controlled within ± 5%.
New energy cable (such as PV cable Wind power cable) mostly adopts cross-linked insulation layer (improving temperature resistance, such as XLPE resistance to 125 ℃, silicone rubber resistance to 200 ℃), and the cross-linking process directly affects the performance:
Irradiation crosslinking process: improve efficiency and uniformity
use Electron beam irradiation accelerator : Instead of traditional warm water crosslinking, the irradiation dose is precisely controlled (such as 10-20Mrad), and the automatic transmission track (speed 10-30m/min) is used to ensure that all parts of the cable are evenly irradiated (dose deviation ≤± 5%), to avoid local insufficient crosslinking (temperature resistance decline) or excessive crosslinking (brittle cracking).
Setting after irradiation Heat setting process (temperature 80-120 ℃): eliminate the internal stress caused by irradiation, and reduce the shrinkage of cable in use (shrinkage ≤ 1%).
Silicone rubber vulcanization process: shorten time and improve stability
use Continuous vulcanization pipeline (CV line) : The vulcanization time is shortened from 10-15 minutes in the traditional oven to 1-3 minutes (adjusted according to the wire diameter) through high-temperature steam (180-200 ℃) or hot air vulcanization, and the temperature gradient in the vulcanization tube is controlled (inlet → outlet gradually heats up) to avoid silicone rubber bubbles due to sudden heat.
add to Efficient vulcanization accelerator (such as organic peroxide): on the premise of ensuring complete vulcanization, reduce the vulcanization temperature (such as from 200 ℃ to 180 ℃) to reduce the thermal aging of materials.
Cooling and traction synchronization control
use Sectional cooling : The extruded cable is initially cooled by warm water (60-80 ℃) (to avoid internal stress caused by sudden cooling), and then finalized by cold water (20-30 ℃), and installed in the cooling water tank Sprinkler (Water flow is evenly distributed) to ensure uniform cooling of cable surface (avoid bending or ovality exceeding the standard).
The tractor adopts Servo motor drive : Linkage with extrusion speed and take-up speed (synchronous precision ± 0.5%) to avoid cable stretching (conductor elongation exceeding the standard) or relaxation (insulation wrinkling) due to speed mismatch.
Online full item detection integration
integrate Spark tester (Detect the pinhole of insulation layer, the voltage is 10-30kV, and adjust according to the wire diameter) Withstand voltage tester (Test the insulation strength, such as 3kV/5min without breakdown) Partial discharge detector (Discharge capacity ≤ 10pC), automatically mark and stop the machine in case of unqualified detection to avoid batch defects.
For new energy vehicle cables Oil resistance test (Immerse in ASTM # 3 oil for 100 ℃ × 24h, volume change rate ≤ 10%) and Bending resistance test (The bending radius is 5 times of the diameter, and it will not be damaged after 1 million cycles) to ensure compliance with the requirements of the vehicle environment.
Whole process data traceability system
use MES system : Record the production parameters of each batch of cables (material batch, extrusion temperature, irradiation dose, test data, etc.), bind the products with two-dimensional code, and realize the full traceability of "raw materials → production → testing → delivery", so as to quickly locate the quality problems (such as the breakdown of insulation layer of a batch, which can be traced to the abnormal extrusion temperature).
Equipment status monitoring and early warning
Installation of key equipment (extruder, irradiation accelerator, vulcanization tube) Vibration sensor, temperature sensor , real-time monitoring of equipment operation status (such as screw bearing temperature, motor current), prediction of faults through AI algorithm (such as early warning of bearing wear), and reduction of unplanned downtime (goal: equipment overall efficiency OEE ≥ 90%).
Flexible production switching
For multi specification orders (for example, photovoltaic cables need to adapt to 4mm ², 6mm ², 10mm ² and other sections) Rapid mold change system : The mold positioning accuracy is ≤ 0.02mm, and the mold change time is shortened from 30-60 minutes to 10-15 minutes. At the same time, by presetting the process parameter library (temperature and speed parameters corresponding to different specifications), parameters can be called with one key to reduce the debugging time during switching.
Performance up to standard : Ensure that the cable meets the special requirements of the new energy scenario (such as UV aging resistance of photovoltaic cable ≥ 2000h, torsion resistance of wind power cable ≥ 10000 times);
Efficiency improvement : The production speed is increased by 20% - 50% (for example, the photovoltaic cable is increased from 15m/min to 25m/min), and the unit energy consumption is reduced by 10% - 15%;
be even quality : The product qualification rate has increased from 95% to more than 99% (reducing rework caused by poor insulation and out of tolerance dimensions).
The optimization of new energy cable production process needs to focus on * * "material characteristics - process parameters - equipment accuracy" matching * *, improve processability through material pretreatment, ensure performance through precision extrusion and cross-linking process, control quality through automatic detection and data traceability, and finally achieve the production goal of "high performance, high efficiency and high stability" to meet photovoltaic, wind power Strict requirements for cables in new energy vehicles and other fields.
