This is the heart and soul of General Motors' new Chevy Volt hybrid wonder car: a T-shape mass of batteries, weighing 435 pounds and storing enough juice to drive the Volt 35 to 40 miles between recharges.
Less known is that the Volt's T-pack also could power a typical midsize home up to eight hours.
The Volt's lithium ion battery wasn't designed to run refrigerators, computers and hair dryers. But that potential benefit has given rise to an experiment in a Raleigh lab to see whether the Volt batteries also could be tapped as stationary power modules in neighborhoods, office parks and for military applications.
ABB, the Swiss energy conglomerate, and GM have teamed up to study how Volt batteries perform during power outages or times of peak energy demand.
The first phase of the experiment is nearly complete as the lithium ion cells are readied for interconnection with a utility power grid. Three power companies are expected to sign agreements in the coming months to test the batteries, said Pablo Rosenfeld, manager of ABB's distributed energy storage program.
At N.C. State University's Centennial Campus, where ABB has its Corporate Research Center and North American headquarters for the Power Products and Power Systems Division, a Volt T-pack rests on a lab floor, wired to equipment and monitors. The battery is rapidly drained and charged, simulating how it would be called to duty in a neighborhood.
"Energy storage really is the Holy Grail," ABB spokesman Bob Fesmire said. "If you find a reasonably priced way to store large amounts of energy, it would solve a lot our energy issues."
The ABB-GM battery experiment, which began in September and will continue into next year, is one of several dozen around the world testing lithium ion batteries for utility use.
But it is one of the few looking at a second life for batteries taken from electric cars. Charlotte-based Duke Energy also is doing a pilot study in Indiana with Itochu, a Japanese company with energy and technology interests. It remains to be seen whether used batteries are preferable to new batteries, said Mike Rowand, Duke's director for technology development.
"What is a given is energy storage," Rowand said. "Intuitively, a used battery is going to be cheaper than a new battery, but if 50 percent of the cost is taken up in repurposing it, then it may not be such a great deal."
ABB's core business is building electrical substations and transmission lines, as well as industrial electric motors, drives and wind turbine generators. The company employs about 1,500 people in this state, including nearly 600 in Raleigh andCary, ABB's North America corporate headquarters.
The company's battery credentials include building the world's most powerful battery in 2002, a 40-megawatt colossus from nickel-cadmium that's as big as a soccer field and two stories high, used by an Alaskan rural cooperative for emergency backup.
Lithium ion batteries, widely used in laptops and cellphones, are cheap and small enough to make electric cars a practical reality. After about a decade, however, a Volt's $10,000 T-pack will wear out and lose about 30 percent of its storage capacity, requiring more frequent charging. GM's warranty covers the batteries for eight years or 100,000 miles.
It's widely assumed that aging batteries will have to be replaced, giving the auto industry about a decade to figure out how to extend the value of used batteries.
Meanwhile, the power industry is looking for ways to manage electricity supply as utilities are adding renewable resources, such as solar and wind, which produce electricity on their own schedule, not necessarily when it's most needed.
"The idea is that used batteries would be even more low-cost than a new battery," said Haresh Kamath, energy storage program manager at the Electric Power Research Institute, the power industry's research arm in Palo Alto, Calif. "For utility purposes it's been very difficult to make batteries pencil out in terms of cost."
Ultimately the ABB-GM study will determine whether the benefits of reusing Volt batteries are worth the cost when compared to other available options. Those could include buying power on the wholesale market, building power plants, or paying customers incentives to participate in energy conservation programs.
ABB teamed up with GM in September and has spent several months creating a lab prototype of the battery pack to be tested in the field.
More than 1,000 individual cells will be reconfigured into a boxy cabinet that will contain the equivalent of five T-packs, holding enough power to keep a half-dozen homes running for at least several hours.
ABB is running final tests on the inverter and software that will link the batteries, which operate on direct current, to the power grid, which uses alternating current.
The inverter will monitor the power supply and draw electricity as needed, functioning as a power management system.
ABB has yet to determine how the batteries will be cooled in the summer and warmed in the winter, said Sandeep Bala, an ABB engineer in Raleigh. Lithium ion cells are prone to overheating, controlled in the Volt with liquid coolant.
"It's clearly an opportunity to extend the value of the batteries off the road," said Pablo Valencia, GM's senior manager for battery life cycle management. "The intent is to create a market."
