Every two years, the University of Michigan Solar Car Team has to make a decision: Make its next car radically different or iterate on tried-and-true designs. This time around, sticking with a familiar build was an easy choice. After all, if your last vehicle resulted in a university-best finish at a global competition, why change what works?
With its long, slender body, the new vehicle, Electrum, might even look like the same car as 2017’s Novum. But those with a keen eye might spot some crucial differences. And the biggest difference of all—a battery innovation—is invisible.
The students unveiled Electrum on July 19 at the Automotive Hall of Fame in Dearborn. With an electrical system overhaul and tuned-up aerodynamics, the team members believe they’ll be able to go faster than ever at the Bridgestone World Solar Challenge this fall, beating their 2017 second-place finish—a best-ever placement for the Michigan team.
Looking at Electrum’s chassis you can see some of Novum’s DNA shining through. This time around, though, the car is slightly more pointed, its cockpit is four inches closer to its nose, and the back of the car where the solar cells are nested is slightly longer and wider. All of these changes were done to boost aerodynamics and efficiency, said Bennet McGlade, team engineering director and recent mechanical engineering grad.
In tandem with the increased area for the solar cells, the team has purchased trapezoid solar cells rather than the rectangles they used previously. While the shape has changed, the solar cells are still multijunction gallium arsenide. The new shape allows for more cells to be packed in the same amount of space.
Under the “hood,” Electrum is anything but business as usual. In a major electrical system overhaul, the team ditched its traditional lithium ion battery cells in favor of something more advanced. They won’t disclose details, but they will say they’re seeing double-digit boosts to power efficiency.
This year, the team is sending a larger number of students, 20, to Australia. Seven raced at the American Solar Challenge in 2018.
The reason for the bigger race crew is partially a result of the second place finish at the American Solar Challenge last summer—the first time the team didn’t win gold at the event in more than a decade.
The loss taught the group how to build better communications channels, said Rishabh Goel, a rising electrical engineering junior and one of the team’s electrical engineers. He says this year Michigan Solar is much more of a team, and they’ve put in a lot of effort to collaborate and share information. Abby Siegal, the team’s Business Director agrees.
“One of the biggest things the team learned was that we aren’t just making systems. We’re making a car,” she said. “Everything we do has to work together if we’re going to win. We need to do everything we can to peel off seconds or minutes.”
With the unveil in the rear-view mirror, the students will continue manufacturing parts and sourcing material for the next several weeks. “We’re always trying to find suppliers and companies to partner with the team however they can,” said Zack Piper, a rising mechanical engineering sophomore and team Operations Director. “Everything we have done so far has prepared us for what’s to come ahead.”
In late August, team members will leave for Australia and continue testing the car. Then, from October 13 through 17, the team will race Electrum through the Australian Outback, competing against more than 40 teams from around the world.
Electrum is the fifteenth car made by Michigan Solar since being founded in 1989. The team has won the American Solar Challenge nine times, had podium finishes in the Bridgestone World Solar Challenge six times, and won its first international championship in 2015 at the Abu Dhabi Solar Challenge. With more than 100 students from schools and colleges across the university, it’s one of the largest student organizations on campus.