Nissan has been trialing an innovative automotive paint aimed at helping lower a vehicle’s ambient cabin temperature in summer and reduce the energy usage of the air conditioning system.

Developed in partnership with Radi-Cool, a radiative cooling product manufacturer, the paint incorporates metamaterial, which Nissan describes as synthetic composite materials.

In November 2023, Nissan began a one-year feasibility trial of the technology at Tokyo International Air Terminal at Haneda. The OEM’s “cool paint” was applied to a Nissan NV100 service vehicle operated by All Nippon Airways (ANA) airport services.

“With its large, open tarmac, Haneda airport provided the perfect environment to conduct a real-world evaluation of the paint’s performance under an exposed high-temperature environment,” Nissan said in a news release. “Although still in the testing phase, the results to date have been impressive.”

Parked side-by-side under the sun, the exterior surfaces of the Nissan vehicle that was treated in the cool paint were 21.6 degrees Fahrenheit cooler and up to 9 degrees cooler inside.

“The paint’s cooling performance is particularly noticeable when a vehicle is parked in the sun for an extended period,” Nissan said. “A cooler cabin is not only more pleasant to enter but also requires less air-conditioning run-time to cool the cabin to a comfortable temperature. This helps reduce load to the engine, or in the case of an electric vehicle, draw on the battery. In both powertrains, an improvement in efficiency is expected as well as occupant comfort.”

The metamaterial embedded within Nissan’s cool paint features two microstructure particles that react to light, Nissan said.

One particle reflects near-infrared rays in the sunlight that would typically cause molecular-level vibrations within the resin of traditional paint to produce heat.

The second particle enables the real breakthrough, Nissan said. It creates electromagnetic waves that counteract the sun’s rays and redirect energy away from the vehicle into the atmosphere. When the particles are combined heat transfers onto surfaces such as the roof, hood, doors, and panels are reduced.

“My dream is to create cooler cars without consuming energy,” said Susumu Miura, Nissan Research Center Advanced Materials and Processing Laboratory senior manager. “This is especially important in the EV era, where the load from running air-conditioning in summer can have a sizable impact on the state of charge.”

While radiant cooling paint isn’t new, it’s typically used for buildings and structures, Nissan said. It’s often very thick, requiring application by a paint roller, and devoid of any clear topcoat, it can leave a chalky residue when touched, according to the release.

Key challenges Miura had to consider when developing an automotive version were to ensure it could incorporate a clear topcoat, be applied via a spray gun, and meet Nissan’s internal standards for paint quality.

Since development began in 2021, Miura and his team have tested over 100 samples, and are currently evaluating a thickness of 120 microns, which is six times thicker than typical automotive paint.

The researchers have confirmed resistance to salt and chipping, peeling, scratches, and chemical reactions as well as color consistency and repairability. As development progresses, Miura and his team continue to explore thinner options that deliver the same level of cooling performance, Nissan said.

Nissan hopes to one day offer the paint by special order and in a variety of colors.

Miura said he sees strong potential for the paint to be used on light commercial vehicles including vans, trucks, and ambulances that spend most of the day out driving.

The paint is one of many other evolving technologies that already make collision repairs more complex or will in the near future. For example, refinishing requires a higher level of precision when it involves a vehicle with radar and sensors used for advanced driver assistance systems making the process important for safety on the road.

Repairers can’t repaint some Mercedes-Benz parts with sensors, according to Benito Cid, Mercedes-Benz USA collision programs manager. Sometimes, replacing the part is the only option.

Other colors have a maximum amount of layers of coating such as primer, paint, and clearcoat, he said in January. Some parts can only be painted one additional time.

Ryan Brown, western technical manager for AkzoNobel, added at the time, “Paint has always been cosmetic. It is no longer just cosmetic.”

He said AkzoNobel tests their products with OEMs to find the correct formulas needed to keep sensors working. Brown also noted that OEMs make and document correct procedures in their manuals, but it is the repairer’s responsibility to follow that procedure.

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