Car Gf32b18490 1920

RFI Shielding for Battery Enclosures in EV

Issues of EMI/RFI Shielding in EVs arise as battery enclosures are now made predominantly out of carbon fibre to achieve weight reduction, our coating solutions are used in series production vehicles.


EMI (Electromagnetic Interference) and RFI (Radio Frequency Interference) are often used interchangeably as RFI falls under as a category of EMI, with EMI being electrical noise of any frequency. (With EMC – Electromagnetic Compatibility also used interchangeably meaning the limit of sources on EM output and the resistance of receivers to EM input). RFI is caused by either electromagnetic conduction or radiation from an external source creating disturbance to an electrical circuit, which in turns leads to interruption, reducing the performance of the circuit. Typically, the external source carries rapidly changing electrical currents.

EMI and RFI is common amongst vehicles due to the high number of electronic elements within them, such as sensors, GPS, in-car entertainment systems, etc. For electric and hybrid vehicles, the risk of interference is even higher as they contain more electrical systems even around their battery and charger. These additional features can affect the other electronic components and systems without EMI/RFI shielding as part of the design of the car. In earlier, EV/hybrid vehicles, their battery enclosures are usually Aluminium or Steel alloys, which mitigate the problem in the original design. However, the need to reduce weight has in recent years led to battery enclosures made predominantly carbon fibre composite.

Electromagnetic Waves 1526374 960 720

Car Engine 231213 960 720

Whilst carbon fibre composite is an obvious choice for lightweighting, it does not offer the same EMI/RFI shielding or indeed fire protection in the case of a thermal event. Although carbon fibre composites are the obvious choice when it comes to high strength to weight ratio, the lack of EMI/RFI shielding compromises safety.

Zircotec has developed specialist coatings primarily for carbon composite manufactured battery box enclosures that have been proven to provide the necessary for RFI/EMI shielding, functioning as an electromagnetic barrier. The coating eliminates the risk disturbances caused by EMI/RFI, improving the safety, performance and efficiency of EV/ hybrid vehicles. Combined with our fire proofing coating these provide a complete solution for vehicle battery enclosures. Our solutions are designed to meet relevant industry standards, such as ASTM D 4935-10.

If you’d like to read more on our other EV specialist coatings such as fireproofing properties and EMI/RFI protection for composite battery enclosures, check out our recent blog post or our EV page.

Get in touch to find out more our RFI/EMI specialist coatings.