Crossing the finish line: Sonnenwagen successfully completes solar race

Sandstorms, bushfires, high winds, extreme temperatures and a far from easy ride … over six days and more than 3,000 km, the Covestro Sonnenwagen traveled the Australian Outback from Darwin to Adelaide powered only by the energy of the sun. Why would we at Covestro support such an extreme challenge to the elements? The answer is: to test our materials to the limit—and bring our commitment to the United Nation’s Sustainable Development Goals to life. By working with initiatives such as Team Sonnenwagen, we’re contributing to making future mobility as sustainable as possible. In the 2019 race as well as the 2017 race (where the Covestro-sponsored team was named Best Newcomer), we brought our innovative materials and technical expertise together with novel designs and production methods to help the students develop a vehicle with optimized safety, speed and resilience. 

While no one would ever want to have an accident, a crash midway through the race put all the safety features of the Sonnenwagen to the test—and it passed with flying colors! The driver was unscathed, and the car suffered only scratches, a broken windshield and few other areas that needed repair. However, the team strengthened their resolve and with great team spirit, a “never give up” attitude and excellent material knowledge, all issues were resolved. Indeed, safety was always a primary focus when designing the Sonnenwagen—particularly since the solar car would be crossing the landscape at speeds approaching 100 km. A number of Covestro materials helped pave the way to a safe trip:

• To protect the driver in the event of a crash, Team Sonnenwagen used Baysafe® polyurethane foam to form a lightweight crashbox that would be able to absorb the impact of 5G of energy – the same amount of force faced by top fuel racers.
  
  
• Temperatures in the desert reached 42 degrees Celsius, and it’s even hotter in the cockpit. A driver’s sweaty hands, combined with sand and dust, can make it hard to grip the steering wheel. A mechanical foamed coated textile based on our INSQIN® technology offers a good grip so the driver can stay in control.
  
  
• The wheel itself had to be lightweight, mechanically strong and flame retardant in order to protect electronics embedded within several steering wheel components. Together with Polymaker, we developed Addigy®—a new flame-retardant polycarbonate for 3D printing that could withstand the grueling temperatures.
  
  
• Protecting the battery cells within the battery module from vibration and high temperatures was another important safety consideration. A lightweight battery cell holder based on our flame retardant Bayblend® PC+ABS blend was the right material for this task. Not only is this material dimensionally stable at very low and high temperatures, it is impact resistant to withstand vibrations during the race. And, because it is lightweight, it significantly reduced the battery’s weight.

An aerodynamic design optimized through wind tunnel testing created a strong foundation for a fast car. We pushed the boundaries of speed even further by using strong yet lightweight materials for the steering wheel, crashbox and other components, as well as a coating that created a smooth surface so air can flow without resistance.  

A new Covestro resin that could withstand the heat of the Australian desert heat also played an important role. The new resin offered higher heat resistance, improving the temperature stability of the electric motor. Greater stability translates into more power and faster acceleration, even when going uphill.

With these and other innovative technologies, the Sonnenwagen solar car reached speeds of up to 144 km/h on the racetrack!

The rigors of the race really tested the ingenuity and persistence of the team. It’s this endurance that exemplifies the spirit of Covestro … always pushing boundaries and innovating boldly as we help our customers move from what’s now to what’s next.

The resiliency of the car was also top-notch: Thanks to durable materials and innovative design, the car and driver were able to complete the solar car challenge despite a crash, finishing in sixth place in the Challenge category — an incredible achievement that surpassed expectations.