Yet it nearly didn’t happen; the group had been working tirelessly for more than a year on the high-speed pod – a futuristic transport capsule designed to travel at 270m/sec and capable of taking passengers 250km in 15 minutes. They travelled to Los Angeles this summer to take part in the 2017 competition, trying out their design on the Hyperloop track at SpaceX’s California headquarters. Their pod’s lithium-ion battery was held up in customs in LA and it looked like it wasn’t going to arrive in time for their first test.
Luckily, the battery was made by Saft, who partnered with the team earlier this year. Saft engineers in the US came to the rescue, building and shipping an entirely new battery system in just one day.
“This battery is not built on the production line because it’s a prototype,” says Ryan Bunge, applications engineer for Saft’s Civil Electronics division in the US. “Through a collaborative team effort, myself and a few colleagues managed to complete the battery build in a matter of hours, which is extremely aggressive.”
FedEx made its normal 3pm visit to the factory, and the Saft team were able to pack the battery in its barrel and catch the delivery driver just as the truck doors were closing. In the words of Christopher Timperio, Swissloop’s technical project lead: “It was epic, you guys really saved the day!”
Swissloop first approached Saft because they were searching for small, lightweight yet high-powered battery packs for their design. The customized battery system is made up of seven lithium-ion MP 176065 XTD cells and is fundamental to the operation of the team’s prototype pod. It enables braking, which is safety-critical because of the speeds involved in Hyperloop, while also allowing data transfer to both the SpaceX team and controlling sensors that measure temperature and acceleration and operate the propulsion mechanism.
During the SpaceX competition, the battery’s reliability also gave Swissloop the edge over their rivals; the prototype pods are tested inside a large vacuum chamber and, unfortunately, many teams’ battery systems failed due to the low-pressure environment in the Hyperloop. Saft’s customized battery solution was fit for the challenge.
The batteries really helped. We plugged it in and it just worked perfectly – and that was actually really cool.Carl Friess Swissloop avionics team lead
Thousands of teams had expressed interest in taking part; around 30 made it to the SpaceX competition this summer. There, each design was subjected to extensive testing and any issues worked through. Swissloop quickly recognized that safety was at the center of SpaceX’s evaluations; they also realized it was beneficial to work with the other teams.
“It was a great environment and there wasn’t too much rivalry,” says Friess. “In fact, all the teams collaborated and even borrowed tools from each other.”
After all of the tests were completed, only five teams made it to the final round – including Swissloop. Using a cold gas propulsion system proved to be beneficial, because no one else had used this innovative method before. It was one of the first decisions the team had taken based on trade-offs between design complexity, time and speed – and it differentiated them from the rest of the competition. The SpaceX judges were so impressed they said they hoped other teams would look at using cold gas propulsion in the future.
“That was also one of the reasons I think we got into the top three,” says Timperio. Although SpaceX chose the winners based on a number of different criteria, the main focus was on design diversity. “We think they wanted to see really different designs in the finals, yet at the same time each design had to show the feasibility of these systems working in the Hyperloop,” says Timperio. “Which is why we think our design was chosen – because we basically designed a small rocket for the Hyperloop, and it worked!”
Back in Zurich, the team have reflected on their experiences and are already working on ideas for their new prototype ready for the 2018 competition.
“We definitely learned where to simplify as much as possible and where to look to add complexity,” says Friess. “For example, some parts of our system were over-engineered or too complicated.”
For the students, the chance to receive feedback from engineers working in a cutting-edge field was invaluable. “Having veteran, 12-year SpaceX team members commenting on how cool our pod was, was a really nice confidence boost,” says Timperio.
Swissloop’s goals for its next design are to ensure safety, simplify the model and increase speed. The team will also be working with Saft to increase the battery’s capacity so the prototype will be able to run for longer. As suggested by the SpaceX team, they would also like to add a temperature sensor to the battery pack.
Swissloop and Saft have both benefited from the partnership – and enjoyed it.
“You gave us a huge edge,” says Friess. “It was really great to have Saft go the extra mile and have Ryan build a battery in a day – that’s just crazy. We couldn’t be luckier to have such a great sponsor.”