Recently we had a great opportunity to help the next generation of engineers compete in Formula SAE® Electric, a collegiate competition to conceive, design, fabricate, develop, and compete with small, formula style electric vehicles. The event is sponsored by the Society of Automotive Engineers (SAE). Our foray into the fast-paced world began when a team from the University of Pennsylvania contacted us after seeing online papers we published on battery tab welding. The team has nearly 100 college students designing and building an electric vehicle, and was working on improvements to their car for next year’s competition.
The FSAE consists of three static events and five dynamic events. The static events include a sales presentation, cost report, and a design presentation where the team justifies design choices and proves to judges that they know how all the components work together. The five dynamic events include acceleration, skidpad, autocross, endurance, and efficiency testing. This is the Penn team’s fourth year competing and they have performed really well. Last year’s car earned them 1st place in design, cost, sales, and acceleration. They even set an FSAE record for the acceleration event in the US, placing 2nd overall!
The team had decided to move from pouch to cylindrical cells in the battery to improve performance – cylindrical cells allow for higher energy densities with the added benefit of more reputable suppliers and more reliable cells. That’s where we came in; AMADA MIYACHI has many resistance and laser welding solutions for battery manufacturing, so this was right up our ally. The team leader asked if they could get some guidance on welding 18650 batteries, 3.7 volt lithium-ion rechargeable battery cells often used to power electric vehicles and power tools.
Prior to Penn visiting our lab, we discussed which process would be best for the particular battery pack size, tab and terminal material, type, and thickness. We also reviewed materials joining requirements, explaining how they vary depending on the battery’s specific type, size and capacity.
We welcomed the three smart, budding young engineers to our facility and thoroughly enjoyed being able to offer insight into welding their battery pack tab to terminal connections.
In this instance (and without giving too much away about the design) laser welding was the preferred process. The team, none of whom had any prior laser welding experience, required only 2-3 hours of training on setup, tooling and a welding procedure before we turned them loose using our standard battery welding 500W single mode fiber laser and scan head system. Within a day or so they had made production parts for their updated battery pack.
Although the project was a bit out of the ordinary – and the customers were a bit younger than usual– the process is actually quite familiar. This is the way we work at our application lab, where eleven full time application experts discuss material selection, part fit-up, and tolerances, as well as help customers select the correct equipment to actually perform the process every single day.
The whole process was fun: the team’s energy was infectious, their enthusiasm for using real life welding equipment was a pleasure to watch, and the parts they made were excellent. I’m betting on this team to win!