Months spent assembling, testing and painting by students from Bochum University of Applied Sciences culminated in the presentation of their development work in Bochum today: The “PowerCore SunCruiser” fitted with electrical steel from ThyssenKrupp Steel Europe is a high-tech solar-powered car of the latest generation. What makes it different: The solar car is a functional vehicle, looking almost like a conventional car, with four wheels, space for up to three people, and even a trunk. The development – the first of its kind in the world – will be put to the test at an international solar car rally in Australia in October.

For the first time, the motor is made with electrical strip from ThyssenKrupp Steel Europe (Bochum site) and subsidiary ThyssenKrupp Electrical Steel (Gelsenkirchen site), giving it a heart of steel. The material is a special soft magnetic steel used mainly in motors for efficient power transmission. ThyssenKrupp is one of the world’s leading manufacturers of this material for high-efficiency electric motors. Hub motors are installed in each of the solar car’s front wheels and transmit power directly to the tires, eliminating large transmission losses. “The use of electrical steel here is a revolutionary step,” says Stefan Spychalski, who has been working on the solar car project at Bochum University of Applied Sciences for over ten years. “Previously we used air core motors, but to achieve higher power we needed to use a core material.” They decided in favor of electrical steel from ThyssenKrupp, which offers numerous advantages: The high-quality, soft magnetic material has low electrical power requirements and provides a controlled magnetic flux for high power density and maximum motor torque.

“We were excited immediately by the project and the dedication of the students,” says Marco Tietz, head of applications technology for non-oriented electrical steel at the Bochum plant. “We knew right away that we wanted to be involved in developing this motor.” The PowerCore SunCruiser thus benefited from two areas of expertise: The roughly 40-strong team of students carried out motor simulations on an in-house test rig based on know-how gathered from the last five solar car generations, while ThyssenKrupp Steel Europe provides a tailored ingredient: “We customized the thickness of our electrical steel to 0.30 millimeters, and we also made changes to the alloy composition and the annealing process,” says Tietz. The result is an electrical steel that helps make very efficient use of the sun’s energy with minimal core losses. The natural energy flows directly from the non-reflecting solar cells on the roof to the motor or in strong sunshine to the battery, where it is stored for use in dull weather. “The drive system delivers the required mechanical and electrical properties,” says Benjamin Geiger, one of the students on the team who already took part in the round-the-world tour by the predecessor model SolarWorld GT in 2012.

The partners have a vision for their joint project: “We want the project to contribute to the targeted development of electrical steel for use in vehicles, tailored to location, motor design and driving cycles,” explains Tietz. “We can use the results of our research on the solar car to position ourselves more strongly in the area of electric mobility.” The engineers are putting their newly gained knowledge to direct use at the company’s “E-Mobility Center Drives”, a unique research and test laboratory in Bochum. Solar car team member Spychalski from Bochum University also knows from experience: “Building cars powered only by the sun’s rays inspires us to be inventive. So when it comes to areas such as weight reduction and energy efficiency, we’re taking a big step towards the car of the future.”

Soon, the solar car motor will face its first major test: In October it will compete in the solar car world championships in Australia (www.worldsolarchallenge.org), a 3,000 kilometer race from Darwin to Adelaide. At previous events, the German team – which will be up against nine other international teams – has always done well in the Australian rally, receiving commendations for concept, speed and design. Now everyone is crossing their fingers that the new model with its revolutionary electrical steel concept will once again score highly.