San Diego, Calif., March 17, 2015 -- San Diego engineers want to drive an electric car from coast to coast in just 45 hours and they need your help. The trip will be made possible by a new technology developed by researchers at the University of California, San Diego: a battery management system that will allow them to swap out and recharge the smaller modules that make up an electric vehicle’s battery. This is easier than swapping out the whole battery, which is cumbersome and requires large, heavy equipment.
Engineers are raising funds for the trip on UC San Diego’s new crowdfunding website: https://crowdsurf.ucsd.edu/
The team is made up of researchers, local engineers and students and is seeking $34,000 in funding. The fundraising campaign has brought in more than $28,000 so far, in part thanks to an anonymous $20,000 gift by a generous donor. The funds will go to tools and materials to build the individual battery modules and their housings. The campaign ends March 25 at midnight. Donors are rewarded by having their name inscribed onto the body of the car, in different sizes depending on the amount of their donation.
“This is a game-changing technology,” said Lou Shrinkle, an electrical engineer who is one of the major sponsors of the project. “This idea may seem straightforward, but there were some tough technical challenges that we had to solve to make this system robust and practical.”
Swapping battery modules could also have far-reaching implications for mobile and decentralized electrical energy storage systems such as solar backup and portable generators. The technology can make energy storage more configurable, promote safety, simplify maintenance and eventually eliminate the use of fossil fuels for these applications, Shrinkle pointed out
“This requires a completely different way of thinking about battery management,” said Raymond de Callafon, a mechanical engineering professor at the Jacobs School of Engineering at UC San Diego. “Electric storage capacity is increased when modules are connected in parallel, but this requires a careful control of stray currents between modules.”
During their cross-country journey, the team will travel 2482 miles. At 120 miles per battery charge, they will have to make a little more than 20 stops during the trip to swap out battery modules. Each stop should take about five minutes, so the total journey should be about 45 hours.
The goal is to set out from San Diego sometime in the fall and stop at seven check points, including Phoenix, Albuquerque, Oklahoma City, Memphis and Atlanta, before arriving in Charleston, S.C. The crew will consist of six to eight people: one driver and one navigator in the electric car, two in the chase car and the rest in a vehicle with sleeping accommodations. Team members rotate duties. The electric vehicle they plan to drive is a converted Volkswagen GTI outfitted with a DC, series wound Warp 9 electric motor and a water cooled Soliton 1 controller. It can generate up to 200 horsepower and sustain 110 horsepower consistently. The car will also feature an integrated heads-up display to actively monitor power usage within the modules and battery.
Algorithms for charge estimation and current control
A team led by de Callafon designed the algorithms for charge estimation and current control, implemented in an embedded system that is part of the battery management system for each module in the car. The algorithms will be able to handle battery modules with different charge levels, chemistry, age and condition and keep the modules working together uniformly.
Xin Zhao, a graduate student who is part of the team, explains that rechargeable, removable battery modules in electric cars would solve numerous problems. Being able to simply swap and combine battery modules would eliminate range anxiety and extend the range that cars are able to travel indefinitely — the average range of most affordable electric vehicles is about 70 to 100 miles per charge. Batteries themselves take 4 to 12 hours to charge with conventional power sources. Newer, fast-charge technology still takes about 30 minutes and involves running very high power through batteries, shortening their lifetime and reducing safety.
The team says there are many advantages in their approach of recharging and swapping out smaller modules within a large battery. The approach allows for a separation between the purchase of an electric vehicle and its battery pack. The price of electric vehicles would drop by about $10,000 if removable battery modules are leased rather than built into an electric vehicle.
Also, as of today, more than 40 percent of people living in cities don’t have access to wall outlets to charge their electrical vehicles at the curb or in a garage. Exchangeable modules could be taken out of the car and recharged at home. Exchangeable modules would also allow an expanded mix of chemistries and energy densities lowering costs and improving range. Removable batteries could even be brought into the home to be charged and be part of an electricity back-up system.