Energy

Nissan, GM Give EV Batteries a Second Life

Automakers have begun harvesting batteries for use in stationary energy storage applications.

Reused batteries could expand the energy storage market, and make EVs more affordable.

The Nissan Leaf went on sale in December 2010, which means that the batteries in the earliest models of the world’s most popular electric vehicle need, or will soon need, to be replaced. Those batteries are not necessarily bound for the recycling bin, though: on Monday Nissan announced the first commercial arrangement to use “second-life batteries,” recovered from EVs, in stationary energy storage systems.

Nissan formed a joint venture with Sumitomo Corp. to develop second-life battery applications not long after the Leaf first appeared. The automaker is working with energy storage supplier Green Charge Networks to redeploy the used batteries in systems for commercial and industrial customers. The announcement from the Japanese automaker came the day before GM unveiled its own battery reuse program: an administration building at GM’s Milford Proving Grounds in Michigan is now equipped with an energy storage system that uses batteries collected from Chevrolet Volts. GM made its announcement Tuesday at the Advanced Automotive Battery Conference in Detroit.

Over time, EV batteries, which often charge and discharge multiple times over the course of a day, lose the ability to propel a vehicle; but they can still function in less demanding, stationary applications. “A battery is like a transmission or an engine: it’s available for remanufacture or reuse,” says Pablo Valencia, GM’s senior manager of battery lifecycle management. “The difference is in the battery application, you can use it on the grid.”

The Volt battery system, not yet on the market for commercial uses, is being deployed to supplement renewable power generation at the Milford facility, making the facility a net zero building, says GM. The company plans to commercialize the system in the future. Nissan and Green Charge are marketing their storage system for companies to manage their utility demand charges, substituting battery power for electricity from the grid at times of peak pricing. Both companies, along with Toyota and other EV makers, foresee a thriving market in retired EV batteries that can supply power to homes and businesses.

Ultimately, automakers seek to fully exploit the energy storage capacity of EVs by incorporating EV batteries not just after their useful transportation life, but while they’re still installed in cars, using vehicle to grid, or V2G, systems. That technology could provide significant benefits—including regulating the frequencies on the grid to smooth the power load and lowering usage during periods of peak demand—to utilities and customers as more vehicles become electrified. One of the stronger advocates of V2G technology is the U.S. Department of Defense, which has invested around $20 million to install 500 V2G-enabled vehicles at bases around the United States.  

Such systems require bidirectional capability—the vehicle must be able to send power back to the grid as well as take it from the grid. That’s not yet found on vehicles sold in the states, but in Japan, Nissan and Mitsubishi already sell cars with two-way charging systems. Nissan’s Leaf to Home system can supply an average Japanese home with two days of electricity in case of a power outage.

For the near term, though, it’s mostly former EV batteries that will supply power back onto the grid. By using “pre-owned” batteries, Green Charge and other energy storage suppliers can reduce their costs and, presumably, the prices they charge customers: “Having this type of system available will expand the energy storage market,” says Brad Smith, the director of Nissan’s battery unit in the U.S.

It could also improve the economics of EVs, which still carry a hefty premium compared to internal-combustion models. While the cost of battery packs has fallen rapidly, they still make up as much as one-third of the total price of an EV. Giving the battery a resale value, as it were, could open up the EV market to a wider set of customers.

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