The special feature of the new development is that the solar roof can be coated in any color, with the solar cells integrated invisibly, for which the Fraunhofer researchers in Freiburg rely on shingle interconnection: The silicon solar cells overlap each other and are electrically connected with a conductive adhesive – and are completely hidden by a freely selectable colored coating and are therefore invisible. The effect, inspired by the morpho butterfly, is achieved by special surface structures that enable high color saturation with good angular stability. “The color possibilities are almost endless,” says Dr. Martin Heinrich, head of PV for Mobility at Fraunhofer ISE.

The functionality of the solar roof corresponds to that of a standard metal car roof. In addition, with a nominal power of about 210 W/m², it can provide electricity for a daily mileage of about 10 km with an average electric car on a sunny day. Calculated over one year, the driving range can therefore be extended by about 10%.