The first solar-powered passenger car: solar cells in the bodywork

After winning the World Solar Challenge in Australia multiple times, a group of students from the Eindhoven University of Technology Solar Team, who designed that car, founded the Lightyear company in 2016, with the goal to engineer a commercial solar car.

They took the original concept a step further together with TNO, developing technology for solar powered automotive body parts based on cost efficient technology. The solar cells are used for mass produced conventional solar panels and have been optimized, with performance, reliability, aesthetics and safety going hand in hand.

TECHNOLOGICAL BREAKTHROUGH

Realizing PV for solar powered cars requires overcoming two challenges. First, the panels must be curved in multiple dimensions to follow the body of the car. This is necessary for both aesthetics and aerodynamics. Crystalline silicon PV solar panels, which are by definition rigid, have been modified making it possible to integrate the solar cells into the roof, bonnet and tailgate, closely following the shape of the car.

The Lightyear One is designed to be extremely aerodynamic, which means that air and rolling resistance are very low. In order to follow these lines, the panels had to be curved in two directions. Such a solar roof is unique and as a result, Lightyear is ahead of the international competition. 

The second is optimizing the performance of the solar panels on different parts of the car in the range of dynamic illumination conditions they will experience in operation. TNO’s conductive back contact foil technology is used to realize smart and flexible module designs. 

The curved solar panels cover an area of approximately five square metres. In Amsterdam, in a sunny year, this could at least halve the number of times the car needs to be charged since the car generates energy via the solar modules both parked and while driving. In summer months, periods, charging may often be completely redundant. 

The great performance of the solar integration in the car can be attributed to a technological breakthrough, developed by experts from TNO, for which extreme ageing tests were carried out at TNO's research facilities in Petten. TNO experts in the field of automotive have also consulted on the design, balancing energy, materials, use logistics and safety.

APPLICATION AND UPSCALING

The new technology of solar cells integrated in materials is also important for application in other areas, such as the built environment. The curved, lightweight PV modules can be used in facades, roofs and many other conceivable surfaces. Because shape, size and colour are no longer an obstacle to harvesting solar energy, aesthetic solutions for homes and buildings are possible. TNO has a comprehensive technology toolbox available for applying integrated solar modules on an extensive array of surfaces in a wide range of sectors.