Chalmers Solar Team competed in 2019 for the first time in what is called the world's largest solar cell car competition, The Bridgestone World Solar Challenge. The basic idea of the competition is to push the technological boundaries of what can be done with solar power. The World Solar Challenge, which takes place every two years, had to be canceled this year due to the pandemic. Instead, an alternative race called Solar Challenge Morocco was arranged. Each team had to drive 250 km on public roads divided into five days. The goal was to get to the finish line as quickly as possible only with the help of energy from solar cells mounted on the car. Except for a smaller battery that was used in the start.
Six teams competed against each other in the same class as Chalmers, which this year lined up with a new car. All the teams managed to reach the finish line, which was an achievement in itself as many teams in previous competitions had to give up. In addition to being able to get around with only solar energy, the car must also withstand sometimes quite tough conditions in the form of heat, wind and often hilly and bad roads. Chalmers placed sixth in the competition, but the conditions for the different teams have also been very different. Many of the teams have been in place for many years and the economic conditions have not been equal.
“We have built the solar cell car at Chalmers almost entirely ourselves with relatively small funds in just over a year. That we have designed, constructed and managed so much on our own is a big difference compared to the other teams. So, we are very satisfied with our efforts, says Alexander Andersson who is currently studying his master's.”
Getting through Morocco's barren desert landscape was an adventure. For example, some of the cold desert nights were spent on blankets outdoors. One of the days the solar cell car stopped, and it took a few hours of troubleshooting before the problem could be fixed. It turned out that there was a loose electrical connection, probably due to the somewhat bumpy road. The entire team was also involved in the strategy while driving as energy data could be monitored continuously from the accompanying cars. For example, drivers could be instructed to adjust the speed for certain distances to avoid clouds and maximize solar energy. The top speed for Chalmers car was around 100 kilometers per hour and for the best team about 140 kilometers per hour. Each driver team consisted of three people who took turns driving, plus two reserve drivers.
Even though it was a competition, and there was a battle to win, the atmosphere between the teams was all and all familiar and helpful.
"Yes, in case of problems, we helped each other, and we shared some ideas between each other. For example, many wanted to know more about the material in our specially built body. But some things were kept more secret, such as electrical systems for example, says Alexander Andersson."
Unique car body in natural fiber
Chalmers solar cell car is built on a steel frame with a body made of flax fiber, and weighs about 200 kg. The choice of flax fiber also attracted a lot of attention as all the competitors' cars were built in carbon fiber. A material that admittedly has good properties but also has a higher environmental impact. Chalmers solar team's goal was to build as environmentally friendly as possible and the choice then fell on flax, which is a type of natural fiber. The lighter the car the better, but the difference in weight was not estimated to be so decisive that carbon fiber was needed. Aerodynamics and the electrical system were considered to be more important for performance, which was something that the team hope to be able to improve for the next competition. The capacity of the solar cells is 800 watts.
Many different skills required
Chalmers Solar Team consists of people with a background from many different educational programs at Chalmers because there are many pieces that will fit. It is a comprehensive project that is not just about building the solar cell car. A large part is about managing contacts with sponsors and managing logistics and media.
"It has really been a very fun and educational project to be involved in. What we have learned in the courses at Chalmers has really come in handy. You also get to know people in a completely different way compared to regular project work, and everything you do is real, says Caroline Reinisch, who is studying her second year at Chalmers."
The team will probably continue to work with the same concept before the next competition, depending on what the rules look like. It is hoped to be able to work more with simulations and expand the team and the structure around the team. Anyone who is interested and wants to know more can contact Chalmers Solar Team via their Facebook page.
Chalmers Solar Team is a student association that was started with the help of Göran Gustafsson, senior lecturer at the Department of Industrial and Materials Science at Chalmers. The Department of Industrial and Materials Science has also provided financial and administrative support.
"Chalmers has been our greatest strength and what made the project possible. Both that we have been able to be on campus for the construction and the support we have received. We also want to take the opportunity to thank all the other sponsors who helped us in various ways, say team members Caroline and Alexander."
Text: Marcus Folino
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