Covestro Sonnenwagen

6th Place

at the Bridgestone World Solar Challenge 2019

David Fewchuck Spirit of the Event Award

Our team spirit and the will not to give up after the accident convinced the jury.

Event Safety Award

We impressed the jury with the safety precautions that ensure the health of the driver.

Technische Details

Nach der Entwicklung im Jahre 2018 und der Fertigung 2019 wurde der Wagen am 22.07.2019 der Öffentlichkeit präsentiert. Der Covestro Sonnenwagen kommt allein mit der Batterie mit einer Akkukapazität 5kWh 500km weit. Die 2,6m² Solarzellenfläche erzeugen dabei eine Peakleistung von einem Kilowatt.
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After development in 2018 and production in 2019, the car was presented to the public on 22.07.2019. Solely with the battery the Covestro Sonnenwagen can travel 500km. The 2.6m² solar cell surface generates a peak power of one kilowatt.

/// ELEKTROMOTOR /// 890 GAA-ZELLEN /// ALLRADLENKUNG /// STRUKTUR /// 5KWH BATTERIE /// AERODYNAMIK

/// ELEKTROMOTOR

Der Covestro Sonnenwagen wird angetrieben von einem selbstentwickelten Axialflussmotor mit einem Wirkungsgrad von >96%. Der Motor weist eine Nennleistung von 1kW auf, kann jedoch eine Peakleistung von 15kW erbringen.

/// 890 GAA-ZELLEN

Wir nutzen für den Covestro Sonnenwagen 890 Galliumarsenid-Zellen auf einer Fläche von 2,64m². Durch die hohen Wirkungsgrade und der sehr guten Temperaturbeständigkeit werden sie häufig in der Raumfahrt eingesetzt. Unsere Solarzellen erzeugen einen Ertrag von 1kW bei einem Wirkungsgrad von über 34%. Das Gesamtfahrzeugkonzept ergab beim Covestro Sonnenwagen das platzieren von Solarzellen in Bereichen, die während des Rennens zum Teil verschattet werden. Die Ergebnisse aus aerodynamischen Simulationen wurden dazu mit einem eigens entwickelten Verschattungstool verglichen.

/// ALLRADLENKUNG

Die Allradlenkung des Covestro Sonnenwagens besteht aus zwei verschiedenen Fahrmodi für High- und Lowspeed. Zum einen können wir bei hohen Geschwindigkeiten die Ausrichtung des Fahrzeugs zur Fahrtrichtung verändern und so die Anströmung des Covestro Sonnewagens bei Seitenwinden verbessern, zum anderen ermöglicht sie dem Fahrer eine gute Manövrierfähigkeit bei niedrigen Geschwindigkeiten und dennoch kleinen Leitwinkeln.

/// STRUKTUR

Ein effizienter Wagen muss möglichst leicht gebaut werden. Mit CFK als Hauptmaterial wiegt der Covestro Sonnenwagen nur 164 kg. Der selbstentwickelte Überrollbügel sorgt zudem für die Sicherheit des Fahrers.

/// 5KWH BATTERIE

Unsere Batterie bestehet aus 418 Lithium-Ionen-Rundzellen mit einem Gesamtgewicht von 24,2kg.

/// AERODYNAMIK

Der Luftwiderstand des Covestro Sonnenwagens ist vergleichbar mit einem gewöhnlichen Außenspiegel eines PKWs. Damit wir den aerodynamisch besten Wagen entwickeln, optimieren wir nicht nur Winde von vorne, sondern nutzen Seitenwinde, um wie ein Boot zu segeln und dadurch unseren Widerstand nochmals zu reduzieren.

Top Speed

144 km/h

Weight

164 kg

Year of construction

2019

Reach

500 km

How did we develop the Covestro Sonnenwagen?

Implementing a solar car means a lot of work. All teams are working with full energy on our goal.

The all-wheel steering allows the Sonnenwagen to be optimally aligned with the wind direction and the closed carbon rims prevent additional air turbulence in the interior.

Jan Wiartalla – Head of mechanical department

The mechanics team has taken up the challenge of building an innovative and competitive racing car for the world’s toughest solar race within just two years. For this purpose, we are divided into expert groups such as chassis, steering, brakes and structure in order to contribute to the development in the best possible way, depending on personal skills and experience.

All departments of Team Sonnenwagen Aachen are in constant and close contact with each other to ensure that all individual developments ultimately fit together in a coherent overall concept. In this way, technical questions can be clarified immediately, interfaces can be defined and innovative solutions can be developed. We are convinced: a team is more than the sum of its members!

The 890 solar cells generate a yield of up to 1 kW with an efficiency of 34% and cover an area of 2.6 square metres. With the 5 kWh battery, the Sonnenwagen can cover 500 km at 90 km/h. The developed axial flux motor generates a nominal output of 3 kW.

Christopher Herget – Head of Electrical Engineering

The classic electric drive train consists of battery, inverter and motor. A solar car also has a solar panel and the associated power electronics. In the future, we will not only drive electrically, but may also “tank” our energy directly from the sun. To do this, we have first put together a solar panel of highly efficient solar cells that are otherwise only used in space travel. In this way, the main energy requirement of the Sonnenwagen can be covered during the race. To avoid having to stop directly when the sky is cloudy, we have also built a compact battery with a high energy density that allows the solar energy to be stored temporarily. Finally, in order to be able to convert the electrical energy into mechanical drive power, we developed an ironless axial flux motor. This is operated with an inverter specially optimised for solar racing cars.

In addition to the power supply, all electrical components communicate with each other via the vehicle electrical system. To enable the vehicle to be controlled, an on-board computer has been developed that communicates with all the vehicle’s electrical components. It functions as the interface between the vehicle and the driver. Among other things, electronics for reading the “accelerator pedal” were developed and the corresponding control of the inverter was programmed. At the same time, the computer collects all the messages and data that the electrical components communicate via the on-board power supply and makes them available to the accompanying vehicle of the sun car via radio. The corresponding hardware with the corresponding code was also developed and implemented for this purpose. In addition to reliability, the main focus of the circuit board design was on efficient implementation.

The aerodynamic design of a wing allows us to use the sailing effect. Compared to the 2017 Sonnenwagen, we have halved the drag.

Christoph Glasmacher – Head of Aerodynamic Department

In the beginning is the Aero. To be successful at the World Solar Challenge in Australia, an aerodynamic design is essential.
We develop the outer shell of our vehicle and are therefore largely responsible for the overall concept and are in close contact with the other departments.

Our goal is to develop a low-resistance, stable design for our solar car that is optimized for driving performance. We are convinced that our development work will produce a first-class design thanks to state-of-the-art CFD simulations, wind tunnel tests, intelligent system integration and continuous model optimization.

5327 lines of code, 15 months preparation, 10^99000 possible speed profiles, 370 days weather data, 10 vehicle parameters

Felix Meyer – Head of Driving Strategy

This is where all information about the Sonnenwagen, the weather conditions and the course of the race comes together. Our strategists form the head of the team during the race. Using sophisticated algorithms and state-of-the-art measurement technology, they determine the optimum speed and steering angle of the Sonnenwagen.

The tasks include transmitting vehicle data, calculating the fastest and most energy-efficient speed and communicating with the driver and the rest of the team. In addition, this year the strategists are relying on their own weather and distance measurements as well as intelligent monitoring of the Sonnenwagen. In this way they are always one step ahead of the competition.