future view

The electric car that powers itself with solar energy

24 June 2019 • 3 min reading time

It started in 2013 with winning the World Solar Challenge in Australia. A tough journey of about three thousand kilometres across the desert with the first family car fully powered by solar energy: the ‘Stella’. Now the prototype of the solar car Lightyear One, which will be on the market in 2021, is being presented. ECN part or TNO is helping develop a breakthrough innovation. These are 3D curved, lightweight and high-efficiency PV panels integrated in the body of a car.

Read more about the Lightyear One and the breakthrough innovation technology 3D curved, lightweight and high-efficiency PV panels from TNO

Towards ubiquitous Solar Energy

“Thanks to the collaboration between Lightyear and ECN part of TNO, which developed this unique module technology, we were able to incorporate solar cells in the roof, bonnet and tailgate. We're talking about crystalline silicon panels that are normally flat. Now they are made in a slightly curved shape and follow the aerodynamic line of the car we designed. An unprecedented achievement. We are at the forefront of this worldwide,” says Lightyear’s Durandus Dijken, who is responsible, together with Simone Regondi and Arjo van der Ham, for the development of the solar panels.

Family car for daily use

Immediately after winning the World Solar Challenge, the students knew for sure: we are going to turn this into a business. That was Lightyear in 2016. The Stella had to become the future of sustainable driving. The world had to see that you can make a five-person car that ‘refuels’ only on sunlight. For years, Dutch teams have been winning races with fast, single occupant solar cars, but the Stella was all about making an everyday family car. The interest didn’t take long in coming: the Lightyear One already has more than a hundred advanced orders.

double curved panels

The prototype was created in close cooperation between the two parties. The last phase went very fast. Scientist Jan Kroon of ECN part of TNO: “We had given ourselves a year to make double curved solar panels in the roof, but thanks to intensive cooperation we did the job within six months. Bending the traditional panels is already quite a task, but in this case it had to be done in two directions. A car roof is spherical, so you have to be able to bend the panels twice.”

extremely aerodynamic

For Lightyear, that was an absolute prerequisite. The Lightyear's design is extremely aerodynamic. As a result, the air resistance is very low, but the challenge was all the greater to be able to equip the exact aerodynamic shape with solar cells.

Durandus Dijken: “It was certainly not a solution that ECN part or TNO had on the shelf. We had to work hard together. A slight curvature in one direction with silicon cells is possible, two directions presents a real headache. It’s like pressing a sheet of paper into half a soccer ball without making any folds. But it worked. With panels in the roof, bonnet and tailgate, we cover an area of five square metres.”

leading the way

The Lightyear One is not ready for production yet, but compared to the Stella, the prototype is already very advanced. The applied technology was patented about a year ago. It means that the company is at the forefront of providing a unique solution. The prototype should lead to a marketable product by 2021.

“The Stella was purely about performance, showing that you can drive a solar-powered car with five people on board. Now, with TNO, we have taken huge technological steps to harvest energy while driving, the car is aerodynamic, lightweight and electric motors have been incorporated into the wheels. So no loss in the transfer of energy from engine to wheels, as is the case with today's electric cars. Energy consumption has been further reduced and the number of kilometres driven on solar power has been increased. The next step is now to optimise reliability and safety,” says Durandus Dijken.

optimising safety

The Netherlands Enterprise Agency has already granted a subsidy for these last steps. Whereas Lightyear One is working closely with the experts in Petten on the development of the double-curved solar panels, it is Helmond that steals the limelight in this phase. Here at the Automotive Campus, TNO Automotive works together with numerous parties to ensure safe, sustainable and efficient traffic.

Jan Kroon: “Throughout the project, experts have worked together in the fields of energy, materials, production technology, reliability and safety. In the project with Lightyear, we developed a technology toolbox that is suitable for making a wide variety of solar panels that we can use in other sectors as well. Think for example of construction, where there is great interest in solar panels that you can integrate into buildings in any shape, size or colour.”

Durandus Dijken: “For us, that is also the beauty of TNO’s breadth and international network. They bring you into contact with knowledge institutions and with other companies outside your own world. That’s what it’s all about these days: you can do a lot on your own, but in partnerships with others you can often do a lot more.”

future view

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