As electrification transforms the transport and mobility landscape, manufacturers are under increasing pressure to source high-performance, scalable, and validated surface coatings that meet electrical insulation, thermal protection, and durability requirements.
At BCW Treatments, we’ve responded to this challenge by investing in a purpose-built, automated powder coating line, capable of delivering dielectric coatings and general powder coatings at production scale. Located in Wellingborough, our facility is engineered specifically to support OEM and Tier 1 customers in the EV, BEV, off-highway, and motorsport sectors.
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What Are Dielectric Coatings and Why Are They Essential for EVs?
A dielectric coating is an electrically insulating barrier applied to a metallic component to prevent short circuits, partial discharge, and thermal runaway in high-voltage systems. These coatings are essential in battery enclosures, busbars, AC-DC converters, inverters, and motor housings, particularly in EV applications where voltages often exceed 400–800V.
Unlike standard powder coatings, dielectric coatings must meet specific dielectric strength (kV/mm) thresholds, offer thermal resistance (to >150°C), and maintain insulation performance over the component’s entire lifecycle, often across millions of vibration cycles, high humidity exposure, and severe thermal cycling.
Our in-house process uses dedicated powder chemistries (typically epoxy-based) specifically formulated for high dielectric strength and adhesion performance on aluminium, copper, and hybrid substrates.
Dielectric Coating vs. Standard Powder Coating – Key Differences
| Feature |
Standard Powder Coating |
Dielectric Powder Coating |
| Primary Function |
Aesthetics / corrosion resistance |
Electrical insulation under high voltage |
| Film Thickness |
60–100μm typical |
150–500μm depending on voltage requirements |
| Electrical Properties |
Low |
Dielectric strength >25–50 kV/mm (varies) |
| Cure Cycle |
Standard oven bake (180–200°C) |
Precisely controlled thermal cure |
| Substrate Prep |
Degrease, Passivate, Blast |
Grit blast + thermal degas |
| Quality Control |
Visual + thickness, Crosshatch adhesion |
Crosshatch adhesion, holiday test (kV) |
At BCW, we provide both solutions in a single production environment, reducing handling steps and improving lead times.
In-House Dielectric Testing – Faster Turnaround, Full Compliance
Unlike many coating houses that rely on off-site testing, BCW has installed a dedicated on-site Dielectric Test Cell, allowing us to validate coating integrity at scale, in-line with production.
- Tested to customer-specific kilovolt values, typically 1–5kV AC or DC
- Every coated part is individually tested (100% inspection) or tested to a defined statistical sampling plan
- Poka yoke technology is in situ – guaranteeing repeatability and 100% conformance
- Rapid feedback loop for process optimisation and rejection minimisation
- No delays from third-party labs
- Full traceability via digital log files and batch reports
This testing capability is particularly vital for safety-critical EV components and helps ensure OEM validation requirements are met before PPAP or SOP milestones.
Why Full Automation is Critical for Coating Repeatability
Dielectric coatings must be applied uniformly, with tight tolerances on coating weight and thickness. Manual processes introduce unacceptable variability for safety-critical applications. Our automated powder coating line includes:
- 3D laser part detection – Automatically adjusts gun positions and follows the contours of complex geometries
- Twin reciprocators, 16 spray guns – Ensures optimal atomisation, wrap, and penetration on parts with recesses and busbar channels
- Conveyor-driven line (85kg/m) – Supports large and heavy components up to 1.8m x 0.8m x 1.8m in a single pass
- Quick-change booth (<10 minutes) – Enables rapid changeover
- State-of-the-art Powder Centre – Twin sonic sieves and fluidised containers maintain powder in peak condition for application
By combining digital process control, sensor feedback, and repeatable automation, we ensure the high yield, consistency, and validation support OEMs require.
Surface Preparation – The Foundation of Coating Performance
Coating performance begins with the right surface prep. Our line incorporates:
- Multistage aqueous pre-treatment
- Thermal degassing oven to prevent pin holing on porous die-cast substrates
- Grit blasting stations for high-adhesion applications
This preparation process ensures excellent coating adhesion, edge coverage, and resistance to delamination under high-temperature and high-humidity test regimes (e.g., 85/85 testing).
Scaled to Support Production Programmes
Our powder coating facility is designed for serial production, not just prototyping. We currently support customers in:
- Series EV production for battery systems
- Lightweight busbar assembly coating
- Low-volume motorsport and prototype builds
- Off-highway electrification platforms (e.g., agriculture, construction)
We are capable of handling:
- Mixed part types per run
- Heavy and oversized EV components
- Just-in-time production batches with short lead times
With 85kg/m overhead conveyor capacity and batch flexibility, we enable manufacturers to meet programme targets without sacrificing coating quality or traceability.
Our Managing Director, Dr Andy Wilson, is available to discuss how we can align with your quality, validation, and supply chain goals.
Join us at Stand 1819 at the Battery Cells & Systems Expo on 9–10 July at NEC Birmingham.
Claim your free ticket here
Let’s explore how BCW can deliver dielectric coatings that meet performance, volume, and timeline requirements, with no compromises.