Showing posts with label battery. Show all posts
Showing posts with label battery. Show all posts

Friday, October 31, 2014

A Second Life for the Electric Car Battery

The New York Times has an article on improving the economics of electric car battereis - A Second Life for the Electric Car Battery.
As I wrote in a recent Times article on electric car batteries, scientists are expecting big breakthroughs in battery technology over the next five years that will increase the range of electric cars while reducing their cost. But even with these advances, researchers acknowledge that any rechargeable battery will gradually lose its capacity to store energy after repeated cycles of charging and discharging.

Once storage capacity falls below a certain level, the battery can no longer provide the range that electric car owners will expect, according to Micky Bly, the executive director of global battery, electric vehicle and hybrid engineering at General Motors. For its new Chevy Volt, GM expects that level to be around 60 to 65 percent of the battery’s original capacity, he said in a telephone interview.

At the same time, with most of a battery’s useful life still intact, automakers anticipate that it could serve other, less demanding purposes than powering a few thousand pounds of car.

A number of projects and new ventures are already under way to explore second-life applications for lithium-ion batteries. G.M. has announced a cooperative agreement with ABB, an energy technology company. And Nissan has formed a joint venture called 4R Energy with the Sumitomo Corporation.

This month, researchers at the National Renewable Energy Laboratory, financed by the Department of Energy, announced their own initiative in this area, a collaboration with academic and industry partners.

From a technical perspective, a special area of focus for the laboratory’s research will be repurposing these batteries for Community Energy Storage systems on the electric utility grid, according to Jeremy Neubauer, a senior engineer in the lab’s energy storage group. If all goes as planned, in the smart grid of the future electric utilities would distribute thousands of these Community Energy Storage packs throughout the grid to help them manage power flow, especially during peak times or outages.

One pack would store 25 to 50 kilowatt hours of electricity, which could provide power for a few hours to four or five homes. Packs of this size would require stringing together two or three electric car batteries, and the compact size of these batteries lends itself to this purpose, Mr. Neubauer said. He also expects that using second-life batteries would be cheaper for the utilities than buying new ones.

But beyond the technical feasibility, what’s new about the lab’s research will be the focus on testing new financial and ownership models for the car batteries. Ahmad Pesaran, principal engineer on the lab’s study, said, “We want to prove the battery has value beyond its use in the car, and by creating business models, to realize this added value, ultimately lowering the cost of owning the car for the consumer.”
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Thursday, September 11, 2014

Forget Battery Swapping Tesla Aims to Charge Electric Cars in Five Minutes

Technology Review has an article on Teslas Forget Battery Swapping: Tesla Aims to Charge Electric Cars in Five Minutes.
Electric vehicles take too long to recharge. To charge a Tesla Model S just halfway takes five hours at a typical home or public charging station. But in its effort to make electric vehicles more practical, Tesla Motors is quickly reducing the charging times. Last September, it unveiled a network of “supercharging” stations—designed exclusively for its Model S and future electric vehicles—that could charge a battery halfway in 30 minutes. In May, it announced an upgrade that cut that time to 20 minutes. Now Tesla’s chief technology officer, JB Straubel, says the company eventually could cut the time it takes to fully charge the battery to just five minutes—or not much longer than it takes to fill a gas tank.

Straubel isn’t referring to the battery swap technology Tesla recently unveiled (see “Why Tesla Thinks It Can Make Battery Swapping Work”). That system doesn’t charge batteries quickly. It simply takes out a depleted battery and replaces it with a fully charged one. He’s talking about what might be a more appealing option for drivers: recharging the battery in your car while you wait.

“It’s not going to happen in a year from now. It’s going to be hard. But I think we can get down to five to 10 minutes,” Straubel said in an interview with MIT Technology Review. He noted that the current superchargers, which deliver 120 kilowatts of electricity, “seemed pretty crazy even 10 years ago.” Conventional public charging stations deliver well under 10 kilowatts.

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