MUNICH — Buyers of Renault’s new Scenic E-Tech electric SUV won’t be able to order a sliding sunroof. But they can get what Renault says is a better option: The Solarbay sunroof, which automatically dims different segments using electrical impulses to excite particles embedded in the glass.
The technology is available on the Scenic E-Tech, which had its public debut at the IAA Mobility auto show here. It is also an option on the just-launched Renault Rafale midsize SUV.
It is ideally suited for EVs, said Brigitte Savariault, a Renault engineer who worked on the Solarbay roof.
Benefits for electric vehicles over a sliding roof include lighter weight because there are no motors or metal rails, Savariault said at demonstration of the technology at the show.
There is also a gain of 30 mm of headroom compared with a conventional sunroof, Renault says, and the dimming feature helps keep the cabin cool or warm, depending on the outside temperature. Wind noise, which is more noticeable in EVs because they have fewer moving mechanical parts, is also reduced.
Renault worked with Saint-Gobain Sekurit on the Solarbay roof, Savariault said. The supplier calls the technology AmpliSky, which it launched (and trademarked) in 2019.
On the Scenic E-Tech, the roof’s opacity can be controlled by a button or by using Google Voice assistant in Renault’s OpenR Link infotainment system. When the car is shut off, the roof automatically darkens; when it is started again, the roof returns to the previous setting.
The technology, called polymer-dispersed liquid crystal or opacifying glass, works by using electrical impulses to align tiny particles in a thin film within the glass roof.
Opacifying glass, from several suppliers, has been available on a number of high-end models from Mercedes-Benz, McLaren and Porsche, but Renault says the Rafale and Scenic are the first mainstream models to have it, particularly with the ability to dim certain segments individually.
Porsche says the “intelligent” sunroof available the Taycan GTS allows only 15 percent of outside heat to enter the interior, compared with 30 percent for a conventional sliding sunroof.
It will also appear on the 2024 Volkswagen ID7 midsize EV, although without a segmentation option.
The coming Cadillac Celestiq luxury EV will use opacifying glass from SPD-SmartGlass that allows each of the four occupants to control their own roof quadrant, GM says.
Office buildings and airliners are also seen as big markets for the technology, to save money on heating and cooling and to avoid glare for employees or passengers.
Other suppliers that have the technology in their portfolios include Webasto, which calls it switchable glazing, and has integrated lighting into a sunroof with the features. Gentex has shown dimmable visors for drivers and front passengers, as well as opacifying sunroofs.
Maximilian Hofbeck, Webasto’s director of product management, told Automotive News Europe recently that his company forecasts that 80 to 90 percent of future vehicles will have roofs with ambient lighting and segmented switchable glazing. Webasto will start series production of roofs with both features in 2025.