To reduce these electrical issues, dielectric coatings have become a popular solution, such as Parker Lord JMC-700K coating, a thermal-cure epoxy resin.
In EV applications, this coating offers direct adhesion to a substrate while providing superior electrical insulation, heat resistance, and oil resistance. This coating works with various automotive applications, including cooling plates, heat sinks, and motor magnets in electric vehicles. Other applications also include automotive parts and industrial machines.
In comparison to JMC-700K, polyethylene terephthalate (PET) film is a low surface energy coating as compared to JMC-700K. Plus, it is tricky to automate and apply because it is such a big film. PET film is also hard to stick to: the low surface energy of PET films makes adhesion difficult without a secondary process to activate the surface, such as plasma treatment. While plasma treatment does increase the adhesion, it also adds capital expenses and additional steps throughout the process. Otherwise, there's still a higher chance of delamination/disbonding with PET films that can lead to potential issues in battery packs such as hot spots, according to Parker Lord.
Also, compared to JMC-700K, a powder coating does not have the same adhesion properties to the base substrate, so there is a higher risk of coating failure to the base metal. In the coating process, JMC-700K is a 1-component epoxy coating, and unlike a powder coating, it moves to where it is sprayed, adds the company.
The JMC-700K coating process involves covering the cooling plate or heat sink with the material. After this, either a gap filler or a thermally conductive adhesive is dispensed on to the newly-coated surface just before battery installation. JMC-700K can be used on parts and devices that experience operating temperatures from -40°C to +180°C.
As battery packs become more energy-dense, less space remains for dielectric protective materials. Because of JMC-700K’s robust adhesion and good dielectric protection, even a thin layer (75 to 100 microns) has proven valuable for EV applications, Parker Lord concludes.