The new Sonnenwagen will be ready soon

Written by: Daniel Steinke

Team Sonnenwagen Aachen will again be competing for victory in the World Solar Challenge in 2023. During a workshop visit, Covestro employees have already caught their first glimpse of components of the new solar car. Covestro project manager Daniel Steinke talks about the visit.

20230331_The-new-Sonnenwagen-will-be-ready-soon_Daniel_Steinke_1It's pretty cold in here! The thought immediately pops into your head when you enter the unheated warehouse in Aachen's industrial area. The Sonnenwagen team works here from dawn to dusk on the new solar car model. Two of the students are currently assembling two workpieces with millimeter precision and fixing them with screw clamps. A little off to the side, another group is evaluating the latest battery measurement results on their laptops. At the back of the hall, the computer-controlled arm of a milling machine is whirring, working a new component out of a solid polyurethane block.

A couple of Covestro colleagues and I are visiting the team of students from RWTH and FH Aachen, and the picture that presents itself to us is surprising - at least for someone like me who has never had anything to do with solar mobility. The group of young people in their 20s works extremely professionally and is structured like a real company with different teams, team leaders and a board of directors. There are detailed project plans and process descriptions for each step of the work.


Covestro is the main sponsor of the project. The company has been supporting the students for years in developing an ever better solar car. The long-standing partnership is paying off: Over the years, Covestro materials have been used again and again in the solar car - and the solar car has gotten better each time. The team is currently designing a new Sonnenwagen for the world's toughest solar car race across the desert. The time has come at the end of October for the World Solar Challenge in Australia.

Before that, the car has to be finished. The students are working their way from the rough shape to the smallest details concerning aerodynamics, mechanics and electronics. Since the beginning of the year, the first components have been produced in the specially rented workshop. Time is short; after all, the team wants to present the new Sonnenwagen at a festive ceremony on June 5. To keep to the schedule, the students even work in shifts. Everyone is on fire and giving their all: they take the project very seriously.

Covestro accompanies the team on its journey. To this end, there is a virtual meeting every two weeks with me as Covestro project manager, my co-project manager Inga Bargende and the students from Aachen. Covestro specialists from different organizations also regularly take part and support with know-how and material expertise. I always really like the meetings because the atmosphere is trusting and open. They are honest technical discussions about the pros and cons of certain solutions.

The Aachen students make sure that the specific plans remain secret. The shape of the body can only be guessed at during our visit to the workshop and remains a secret even for us for the time being. For this year's race, the team is milling the body shape from polyurethane blocks in a multi-stage process. Afterwards, the students continue to smooth out the final imperfections by hand with sandpaper.

Lina, from the Sonnenwagen team's board of directors, explains why: "Every unevenness on the surface increases air resistance and costs valuable seconds later in the race." The pre-sanded blocks are then lined with carbon mats, which serve as the actual mold for the final body parts.

The Aachen students are also precise when it comes to the drive and the batteries - the heart of the car. When it comes to the drive, the students don't want to compromise and are constantly optimizing it. They have designed, completed, tested, discarded and further improved countless versions of the stator (an important component of the electric motor). In order to get everything out of the car in the race, the electrical engineers check each battery cell individually for its function and whether it delivers the promised performance. Later in the race, this detailed knowledge can mean the decisive advantage and bring victory.

At the beginning of June, the team will present the new car to the public for the first time. After that, the team will have about 3 months for extensive test runs before the new solar car is sent on its long journey to Australia. There, the team will have a few more weeks for the final tuning before the World Solar Challenge starts in Darwin on October 22.

I probably won't be able to be there live. But I will follow the race online and cheer along on my PC. The goal is, of course, first place. And I am sure that with their commitment and dedication, they will achieve it!

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