Infrared Curing of Automotive Refinish Coatings for Electric Vehicles
Autobody shops are discovering that painting and curing refinish coatings applied on EVs can be a bit tricky – especially curing – due to the heat sensitivity of the battery packs.
The challenge is that all EV manufacturers have temperature limitations for their vehicles’ battery packs, and all are different. Even the same manufacturer could have different limitations for their different models.
The problem is that conventional convection spray booths (which are used by most autobody shops) result in temperatures that are right at the limit of virtually all manufacturers’ recommendations.
This is usually right around 140 degrees Fahrenheit (60 degrees Celsius).Furthermore, curing by convection heat will heat-up the entire vehicle, including the interior parts, and not specifically the surface section of the vehicle where the coating is applied.
So, what can a bodyshop do to eliminate the potential issues with electric vehicle battery packs?
The answer is infrared curing!
Infrared radiation does not penetrate more than a few millimeters below the surface of the vehicle, far removed from battery packs and sensitive comfort and convenience electronics.
EXPOSURE TO HIGH TEMPERATURES OVER TIME CAN HINDER BATTERY PERFORMANCE
With traditional oven-bake curing, you can raise the temperature and reduce the time, but you are only trading one potentially harmful effect for another. Lowering the temperature and increasing the time will also not offset possible battery damage. There are no trade-offs.
Medium-wave infrared curing heats up near instantaneously, achieving curing temperatures quickly. Energy is absorbed by the coating on the specific substrate area, and very little heat penetrates the substrate or spreads elsewhere throughout the vehicle. Shorter cure times result in less total potential exposure.
Just what type of damage might occur?
In modern Lithium batteries, high temperatures can break down the barrier between positive and negative charges. This has two unappealing impacts. Since ions can no longer flow freely, the battery will take longer to charge and may no longer charge to 100%.
Additionally, since ion flow is restricted in both directions, the vehicles’ acceleration and overall performance may be compromised.