6000T/M Micro-Arc Oxidation Line for EV Battery Trays with Ceramic Coating and Electrical Insulation

This micro-arc oxidation (MAO) production line is designed for surface treatment of aluminum alloy battery trays used in new energy vehicles (NEVs). The line applies a high-voltage plasma discharge process in an alkaline electrolyte, forming an in-situ ceramic oxide layer — primarily α-Al₂O₃ — directly on the aluminum substrate. Unlike conventional anodizing, the MAO coating is fully integrated with the base metal, providing electrical insulation, corrosion resistance against coolant fluids, and thermal stability under battery operating conditions. The line delivers a monthly processing capacity of 6,000 tons and supports aluminum alloys including 6061, 6063, and 3003. The coating thickness is adjustable within 10–60 μm, with hardness reaching HV 500–1200 depending on process parameters.

Note: Coating hardness and breakdown voltage vary with alloy grade, coating thickness, and electrical parameters. Values above represent typical ranges under standard production conditions. Final specifications are confirmed based on workpiece geometry and functional requirements.

1. Degreasing & Pre-cleaning — Remove machining oils and surface contaminants from the aluminum tray.
2. Rinsing — Two-stage cascade rinse to eliminate residual alkaline cleaner.
3. Micro-Arc Oxidation — Immerse workpiece in alkaline electrolyte; apply high-voltage pulsed DC to generate plasma micro-discharges and grow the ceramic oxide layer in situ.
4. Rinsing — Overflow rinse to remove electrolyte carryover.
5. Drying — Hot air drying or oven curing.
6. Inspection — Thickness gauge, breakdown voltage tester, and visual inspection.

• Electrical Insulation for Cell-to-Tray Isolation — The ceramic oxide layer provides insulation resistance above 10¹⁰ Ω·cm, reducing the risk of electrical leakage between battery modules and the tray structure.
• Coolant Fluid Compatibility — The MAO coating resists degradation from glycol-based coolant fluids commonly used in battery thermal management systems, maintaining coating integrity over extended service life.
• Lightweight Surface Engineering — The treatment preserves the lightweight advantage of aluminum while significantly improving surface durability and functional performance.
• Adjustable Coating Thickness — Process parameters can be tuned to achieve 10–60 μm, balancing insulation requirements against dimensional tolerance for precision assembly.
• Thick-Wall and Complex Geometry Support — The line accommodates large-format trays and trays with deep cavities, integrating with automated loading and transfer systems.

A1: The MAO coating serves three core functions on a battery tray: electrical insulation to isolate the battery modules from the aluminum tray structure, corrosion protection against coolant fluids and environmental exposure, and wear resistance for handling and assembly operations. It also contributes to thermal management by providing a ceramic surface with high-temperature stability.

A2: Hard anodizing (Type III) typically produces coatings of HV 300–500 with thickness of 20–80 μm. MAO coatings achieve higher hardness (HV 500–1200) and are ceramic rather than amorphous in structure. The MAO process also uses an alkaline electrolyte rather than sulfuric acid, which simplifies waste treatment and avoids acid-handling concerns. For battery trays requiring combined insulation and coolant resistance, MAO is often specified over hard anodizing.

A3: For most battery tray applications, a coating thickness of 20–40 μm provides an effective balance between electrical insulation (breakdown voltage ≥ 500 V) and dimensional tolerance. Thinner coatings (10–20 μm) are used where tight assembly tolerances are critical; thicker coatings (40–60 μm) are selected for applications requiring extended corrosion protection.

A4: Yes. The MAO process is compatible with 6061, 6063, 3003, and other aluminum alloys commonly used in battery tray manufacturing. Electrolyte composition and electrical parameters are adjusted based on alloy grade and required coating properties.

A5: Standard lead time is approximately 5–6 months from order confirmation, followed by 2–3 months for installation and commissioning. Final timeline depends on line configuration, site conditions, and customization requirements.