For exported Chinese NEVs, battery pack enclosures and cooling plates primarily require 6061-T6 and 3003 aluminum alloys, machined via 3-axis/5-axis CNC milling. Critical tolerances include overall flatness ≤0.1 mm/m, sealing groove depth ±0.02 mm, and hole po
Quick Answer
For exported Chinese NEVs, battery pack enclosures and cooling plates primarily require 6061-T6 and 3003 aluminum alloys, machined via 3-axis/5-axis CNC milling. Critical tolerances include overall flatness ≤0.1 mm/m, sealing groove depth ±0.02 mm, and hole position accuracy ±0.05 mm. Surface roughness for sealing surfaces must be controlled at Ra 0.8–1.6 μm to ensure IP67/IP68 waterproof ratings.
Definition
Battery pack CNC machining involves subtractive manufacturing of enclosures, liquid cooling plates, and structural supports. Unlike stamped or welded parts, CNC machining ensures uniform wall thickness, precise sealing interfaces, and high structural rigidity—essential for preventing thermal runaway and water ingress in overseas markets.
How It Works
Material Selection: 3003 aluminum is preferred for cooling plates due to excellent brazing performance; 6061-T6 is standard for enclosures requiring welding or anodizing.
Roughing: High-eed milling removes 70% of material with 2–3 mm allowances.
Semi-finishing: Stabilizes thin walls (3–5 mm) to prevent vibration.
Finishing: Ball-nose end mills achieve Ra 0.8 μm on sealing surfaces.
Deep-Hole Drilling: Over 200 threaded holes (M6–M10) are drilled with internal coolant to prevent chip evacuation issues.
In-Process Inspection: Probe systems verify flatness and hole positions during machining.
Common Values and Practical Notes
- Component
- CNC Material
- Machining Process
- Critical Tolerance
- Battery Enclosure
- 6061-T6 Aluminum
- 5-axis machining, face milling
- Flatness 0.1 mm/m
- Liquid Cooling Plate
- 3003 Aluminum
- 3-axis milling, slotting
- Flow channel width ±0.10 mm
- Sealing Groove
- 6061-T6 Aluminum
- Precision grooving
- Depth ±0.02 mm
- Busbar Brackets
- PA66+GF30 / 6061-T6
- Milling, drilling
- Hole position ±0.05 mm
- Skid Plate
- 7075-T6 Aluminum
- High-speed machining
- Thickness ±0.10 mm
Advantages
- Zero Porosity: Eliminates casting defects that cause leaks under high pressure.
- Design Flexibility: Rapid iteration for different battery cell formats (prismatic vs. cylindrical).
- Thermal Performance: Direct machining of cooling channels optimizes coolant flow.
Disadvantages
- High Material Waste: Up to 70% of aluminum becomes chips.
- Long Cycle Time: Large-format parts require 4–8 hours of machining.
- Cost: 7075-T6 material and tooling costs are 3× higher than steel.
Applications
- Overseas battery pack repair centers.
- Battery thermal management upgrades.
- Crash-damaged enclosure replacements.
Comparison
- Process
- Precision
- Sealing Reliability
- Lead Time
- CNC Machining
- ±0.02 mm
- Excellent
- 2–3 weeks
- Die Casting
- ±0.20 mm
- Fair (porosity risk)
- 8–12 weeks (tooling)
- Stamping/Welding
- ±0.15 mm
- Poor (distortion)
- 4–6 weeks
Related Questions
- Why does 3003 aluminum outperform 6061 for liquid cooling plates?
- How does CNC flatness prevent battery pack water leakage?
- What surface treatment (anodizing) is required for battery enclosures?
- Why are 7075-T6 skid plates necessary for Middle East exports?
Conclusion
Exported Chinese NEVs demand CNC-machined battery enclosures and cooling plates with 6061-T6/3003 aluminum, ±0.02 mm sealing groove tolerance, and Ra 0.8 μm surface finish. This ensures long-term reliability in diverse climates, from humid Southeast Asia to sandy Middle Eastern regions.
HYR-CNC Recommendation
For EV and NEV component manufacturing, HYR-CNC recommends selecting high-rigidity VMC, HMC, gantry, turning or 5-axis CNC equipment according to part size, tolerance, material and production volume.