Buses are a natural for electrification. They follow fixed routes, they’re stored in centralized locations and they benefit from loads of torque. Trouble is, batteries are really big and really expensive, especially when you’re talking about something capable of powering a bus.
GE Global Research thinks it has an answer to that problem.
The company’s hybrid systems research team has built a system that combines a high-energy density sodium battery with a high-power lithium-ion battery. It’s betting the technology accelerates the electrification of buses, delivery trucks and other large heavy-duty fleet vehicles.
Why? Because the combination of high-energy and high-power storage capacity could achieve optimal range and performance requirements for large vehicles in a battery of reasonable size and price.
“Public transit and delivery service providers recognize the importance and benefits of transitioning to an electric fleet but are looking for cost-effective solutions to make that possible,” Lembit Salasoo, an electrical engineer leading the project, said in a statement. “With the cost of the battery remaining a principal hurdle, a dual battery system could bring these costs down and help accelerate the electric revolution for bus and delivery truck fleets representing hundreds of thousands of vehicles.”
According to GE, there are 843,000 buses registered in the United States. Many of them — including most of the 63,000 transit buses and 480,000 school buses — travel less than 100 miles daily. That is well within the range of current battery technology.
But most battery chemistries require a compromise between power and energy storage. Lithium ion batteries provide lots of power for optimal acceleration at the expense of storage capacity — aka range. Sodium batteries can store lots of energy but aren’t optimized for power. GE says combining the two provides a good mix of both attributes.
“The beauty of our dual battery system is that it can be scaled to deliver just the right combination of power and storage,” Salasoo said.
GE says the dual-battery system can reduce the cost of a pack by 20 percent compared to using a single chemistry in a vehicle that requires a lot of power and energy storage capacity — like a bus. By combining chemistries, batteries can be optimized to suit specific purposes without having to increase the size, and therefore cost, of the pack.
The research is being done under a $13 million project involving GE, the Federal Transit Administration and Northeast Advanced Vehicle Consortium funded under the National Fuel Cell Bus Program.
Main photo: julien / Flickr. Video: GE
A short clip of the bus in action. You’ll want to turn down your volume.
Via Wired Autopia: http://www.wired.com/autopia/