The Critical Role of Dip Molding in Insulating Copper Busbars for New Energy Applications
- Insulation Requirements in the New Energy Sector
With the rapid growth of electric vehicles (EVs), photovoltaic (PV) energy storage, and charging infrastructure, copper busbars—key components for power transmission—require superior insulation to ensure system safety and reliability.
1. Electric Vehicles
High-voltage copper busbars within battery packs require reliable insulation to prevent short circuits and leakage risks.
2. PV Energy Storage
Copper busbars in inverters and energy storage systems must withstand harsh outdoor environments.
3. Charging Stations
High-current busbars in DC fast chargers demand insulation materials with enhanced thermal resistance and durability.
2. Overview of Dip Molding
Dip molding (Dip Molding / Plastisol Dipping) involves immersing preheated metal workpieces into molten plastic powder. Through heat fusion, a uniform and dense plastic coating is formed on the metal surface.
**Common Materials: **
- PVC (Polyvinyl Chloride): Low cost, excellent electrical insulation
- PE (Polyethylene): Superior weather resistance and low-temperature performance
- Nylon (PA): Outstanding wear resistance and high-temperature tolerance
- Fluoroplastics (PTFE): Exceptional heat and corrosion resistance
3. Advantages of Dip Molding for Copper Busbar Insulation
1. Superior Electrical Insulation
The dip-molded layer offers excellent dielectric properties, with breakdown strength reaching 15-25 kV/mm, meeting strict industry requirements.
**Test Data: **
- Power Frequency Withstand Voltage: ≥15kV/min kV without breakdown
- Volume Resistivity: ≥1×10¹⁴ Ω·cm
- Dielectric Constant: 3.0-4.0 (@50 Hz)
2. Excellent Corrosion Resistance
The coating effectively isolates the busbar from the environment, providing resistance against acid and alkali corrosion in harsh conditions.
**Corrosion Resistance Test: **
- Salt Spray Test: ≥500 hours without rust
- Acid Resistance: 10% H₂SO₄, 48 hours no change
- Alkali Resistance: 10% NaOH, 48 hours no change
3. Strong Adhesion
Through preheating and precise process control, the coating bonds firmly to the copper substrate, preventing peeling or flaking.
**Adhesion Test: **
- Cross-Cut Test: Grade 1 standard (ISO 2409)
- Bend Test: No cracking at 180° bend
4. Uniform and Controllable Thickness
The process allows precise thickness control, typically 0.3-0.8mm, catering to various voltage ratings.
5. Eco-Friendly and Non-Polluting
Dip molding involves no solvent emissions, and unused powder can be recycled, ensuring environmental compliance.
4. Application Scenarios
1. EV Battery Packs
Provides phase-to-phase and phase-to-ground insulation for electrical connections between battery modules.
2. PV Inverters
Insulates internal busbars to withstand complex outdoor operating conditions.
3. Energy Storage Systems
Ensures safe operation by insulating busbars within battery cabinets.
4. Charging Stations
Protects busbars in DC charging modules against high currents and elevated temperatures.
5. Distribution Cabinets
Insulates busbars in low-voltage switchgear to prevent short-circuit accidents.
5. Quality Control Key Points
1. Pre-treatment
Busbars must undergo thorough degreasing and descaling to ensure a clean surface.
2. Preheating Temperature
Controlled within 200-280℃ based on busbar thickness and material characteristics.
3. Dipping Time
Precisely controlled to achieve the required coating thickness.
4. Curing Process
Proper curing ensures stable coating performance after dipping.
5. Quality Inspection
- Visual Check: Smooth surface, no bubbles or cracks
- Thickness Measurement: Verified with micrometers per design specs
- Withstand Voltage Test: Power frequency test with no breakdown or flashover
- Adhesion Test: Cross-cut test achieving Grade 1 standard
6. Tiannuo Technology's Dip Molding Services
Taizhou Tiannuo Electric Co., Ltd. operates professional dip molding lines and comprehensive testing equipment, offering:
- Custom Design: Tailored processing based on client drawings
- Material Selection: Options including PVC, PE, Nylon, and more
- Thickness Control: Precise control of coating thickness (0.3-1.2mm)
- Quality Assurance: Advanced testing equipment and rigorous quality management
- Fast Delivery: Standardized production processes ensuring on-time delivery