Dielectric powder coating

Expertise in high-voltage protection for EV battery systems

Dielectric powder coating for aluminium

Dielectric powder coatings create an insulating barrier against electrical currents on metal surfaces, preventing electrical conduction and protecting against short circuits, electrical arcing, thermal runaway and environmental degradation. They are composed of highly specialised non-conductive particles within the powder coating formula.

Leading the evolution of dielectric coatings: From busbars to aluminium battery enclosures

Dielectric coating is a long established and proven technology, used primarily for insulating busbars - key electrical conductors in power distribution systems. Adapting this technology for insulating thin aluminium sections in EV applications has presented a unique set of challenges. It requires a complete re-engineering of the coating process to meet the distinct mechanical and electrical demands of EV battery enclosures.

With over 40 years’ expertise in surface science, we are experienced in adapting techniques for new purposes. We have identified the risk factors in applying dielectric powders effectively and have refined our powder coating techniques for dielectric powders used in EV battery assemblies, overcoming the challenges presented by the demands of this new application.

We have developed a dielectric coating process for aluminium that provides optimal insulation performance and durability, and ensures compatibility with the stringent requirements of the next-generation EV applications.

Practical experience and technical expertise, used in collaboration with you

We have been fortunate enough to hone our expertise  through working with major OEMs and Tier 1 companies in the EV sector.

This has provided the opportunity to discover many challenges arising in the application of dielectric coatings and to find the best solutions.

Our in-house testing facilities are fundamental to perfecting our processes and we have invested in the best equipment for the job. We have PhD level expertise on our team and regularly collaborate on international research projects. Testing and development is an essential part of our service offering.

To ensure the success of your dielectric powder coating project …..

Proficiency in applying dielectric coatings

Electrical insulation, isolation and temperature regulation is required within battery cells. Fluctuating temperatures can cause the battery cell temperature to rise incredibly fast, known as a thermal runaway, and this brings the risk of battery failure, as does electrical arcing. We use dielectric coatings similar to Resicoat. These coatings provide exceptional resistance to thermal shocks and have high dielectric strength.

This is a quick overview of what is required – and expertly delivered by our team at Powdertech Surface Science.

The coating:-

  • High dielectric strength >30kV/mm 

  • Flammability test UL-94 V-0 

  • Suitable for use in-cell, in-pack and to protect the cooling system

The application:-

  • Applied at the required coating thickness to meet the specifications required for electrical isolation.

  • The coating must be free from any flaws. Any failure in the integrity of the coating would result in unsafe leakage of current.

  • Expertise in masking to apply the insulating coating only where required. Dielectric coatings are designed to prevent arcing within the battery enclosure and therefore must be applied in precise areas to electrically isolate certain parts of the metal. Our years of experience in CAD design and application of masking schemes is essential for the efficacy of the coating.

  • Automated application process to deliver a consistent performance level.

At Powdertech, we don’t just apply coatings - we engineer solutions. Our expertise in dielectric science, precision application, and supply chain integration makes us the go-to partner for EV battery and component manufacturers.

Pre-treatment for dielectric powder coating

It is important to remember that a dielectric coating is also a protective coating for the metal and must perform other functions in addition to insulation and temperature regulation. It must be sufficiently robust for the rigours of a car manufacturing plant and subsequent vehicle usage. The coating must have excellent adhesion ensuring chemical and corrosion resistance.

The first step in achieving a high-performance dielectric coating is to ensure the cleanliness and effective pre-treatment of the aluminium surface. This forms the foundation for reliable dielectric coating for maximum performance and longevity.

Our TiZr passivation process is designed to meet the demanding requirements of EV battery enclosures ensuring long-lasting protection. Without it, adhesion failures, coating inconsistencies, and long-term degradation can occur. Contaminants, oxides, and surface oils must be completely removed to prevent adhesion issues.

Addressing dielectric coating challenges with innovation and expertise

Powdertech’s ability to detect any problematic issues early in the process and find solutions, often innovative ones, is due to our team of our dedicated technical experts working with advanced onsite testing capabilities and ongoing quality measures. What follows is a list of the main issues that need to be addressed for every application.

  • Coating thickness - optimised for both insulation and fit tolerances

The dielectric coating in EV battery assemblies needs to be of sufficient thickness to meet the dielectric properties required. This is specified by the customer. However, if the coating is too thick then the number of battery cells that can be introduced is reduced. This can effect vehicle range and  performance.

At Powdertech, our team fine-tunes the coating thickness to meet the required coating specifications and strike the perfect balance between insulation and space optimization.

The result? A high-performance, space-efficient dielectric coating that meets the specification without compromising on protection.

  • Edge coverage

One of the major challenges in dielectric coating is to ensure even coating coverage, especially on the edges where thinning can easily occur. This will reduce the insulation and lead to potential electrical failures.

Manufacture of the part needs to avoid sharp and sheared edges as these are far more prone to coating failures compared to round and smooth edges. We work closely with customers to advise on part design. It is important to get in touch with us at the start of a project so that the entire process is correct from the outset and the end product can perform flawlessly.

  • Porosity control and other potential flaws

We take all measures to avoid porosity in the dielectric coating. These measures start with thorough cleaning and passivation to avoid outgassing and poor adhesion.

Porosity, if it occurs, leads to microscopic voids, pinholes, or air pockets within the coating layer. In these areas the coating will be too thin, forming a weak point in the insulation. We use Holiday testing to check for any porosity in applied coating. The method uses an electrical current that flows through a low resistance path and triggers an alarm (buzzer) when a flaw is detected.

Batteries in an electric vehicle

Holiday testing to ensure consistency of coating

Testing dielectric coatings

In order to ensure that our dielectric coatings will perform to specification we employ our in house testing equipment.

Before any coating, we ensure that the metal surface is sufficiently clean to receive our TiZr process by testing the surface for cleanliness. See more on the TiZr passivation page and view our short video ‘How Clean is Clean? ‘ on that page.

Specific to dielectric coatings we use Holiday testing to detect any potential flaws in the uniformity of the surface, Hi-Pot (high potential testing) to measure the breakdown voltage and a megohmmeter to measure the insulation resistance. The dielectric strength of a coating is a critical parameter, and Hi-Pot testing verifies whether the coating can withstand the intended operational voltages.

Please visit our Testing & Development page to find out more about these essential tests.

Dielectric Powder Coating Case Studies

At present we can not publish any case studies - as frustrating for us as it is for you! As this is a highly innovative and competitive sector, our clients are understandably carrying out work with NDAs attached. As soon as we are given the go-ahead to publish we will!

More reasons to choose Powdertech metal finishing

 

We carry out a meticulous final inspection - checking dimensions and visual aspects of the parts.

Direct despatch to OEM’s. We are familiar with EDI systems and online booking of transport, direct to end users.

We offer express turnaround in a matter of hours - we are set up for rapid job completion where necessary.

Dedicated warehouse facilities for raw and finished goods.

 
 
 

To ensure the success of your dielectric powder coating project

Let’s build the future of EV insulation together.

 

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