Killer App for E.V.?s: 30-Minute Recharges
This notion ? that buyers may shun the electric cars set to start arriving in showrooms late this year because they can drive only 75 or
100 miles before needing a recharge ? is a powerful argument.Of course, range would not be an issue at all if the car?s batteries could be conveniently recharged in about the same time it takes to top off a gas tank. An ability to replenish batteries in minutes, rather than spending several hours (or overnight) within reach of an electrical outlet, could silence the debate over whether electric cars will ever become practical.
Many proposals have been forwarded, including plans for quick-change battery packs; this concept, like some other inventive solutions, raises serious questions about infrastructure and investments. Lately, though, there has been a greater focus on high-voltage quick chargers that could refill a car?s battery in a half hour or less.
Most charging, experts say, will be done at home and at the workplace, where electric vehicle owners will have hours to connect their cars to high-power units, known as Level 2 chargers, that operate on 240-volt circuits. (Level 1 uses 120-volt household current.) Apartment buildings are also expected to offer Level 2 capability as a perk to attract eco-conscious tenants, though providing more than a few chargers per building may prove to be a challenge.
Still, there will be times when electric cars will be out on the road, running on the electrical equivalent of fumes, and looking for a charge.
The good news is that the top class of chargers, Level 3, includes units that can boost a typical electric car most of the way to full in just 30 minutes using about twice the voltage of a Level 2 charger. The logical place for fast charging would be stopover locations ? a Starbucks coffee shop or a big-box store, for example.
Safety, an important consideration for consumers and regulators alike, becomes a more pressing matter as the electrical current increases. Underwriters Laboratory, the product safety organization, is working with a charger company, ECOtality, and the federally supported EV Project, as well as with others, on certifying the safety of fast charging. According to Gary Savin, vice president and general manager of the laboratory?s power and controls business unit, ?We have to consider how the chargers are going to be used and what kind of environment they?ll operate in.?
Safety is an issue that fast-charge advocates are eager to move beyond. ECOtality?s chief executive, Jonathan Read, said the coming fast chargers would be overengineered and overdesigned to ensure the safety of users.
?We couldn?t be more comfortable with fast charging,? he said. ?We have deployed more than 5,000 fast chargers around the U.S. and never had an injury. We?ve had people charging in snowstorms and in pouring rain without any issues.?
ECOtality recently unveiled a new Blink Level II charger developed with Frog Design. ECOtality, also a partner in the EV Project, will roll out a public fast charger in the fall, and Mr. Read predicts that it will be easy for consumers to operate.
Mr. Savin is among those asking if fast chargers will need the same kind of attendants once employed at gas stations. That is not just a safety question: Mr. Savin said the thicker, heavier cable needed for fast charging could be most easily handled by a trained attendant.
Andrew Tang, senior director of customer care at the California utility PG&E, says he also thinks attendants may be necessary.
Fast charging commands a large power draw even when compared with the needs of an average home. While a Level 2 charger draws up to 60 amperes, the demand of a Level 3 unit is some four times greater.
?Homes are equipped with 200-amp fuse panels,? Mr. Tang said. ?That?s for the whole house.?
But PG&E is supportive of E.V.?s and of fast charging. It has installed a free public Level 3 charger along Interstate 80 in Vacaville, Calif., and it is conducting tests with a Mitsubishi i-MiEV, one of the Japanese E.V.?s (another is the Nissan Leaf, also tested at Vacaville) that uses a Japanese fast-charging standard developed by the Tokyo Electric Power Company. That standard has been finalized for Japan and could be applied in the United States, but separate guidelines for Level 3 are also evolving in this country.
The Tokyo Electric charging standard is licensed in the United States by Aker Wade Power Technologies of Charlottesville, Va. The company, which has built 9,000 fast chargers for forklifts, airport vehicles and other commercial applications, says fast charging is safe.
?We?ve never had a single safety incident,? said Jeff Taylor, the company?s chief operating officer. ?We?ve never shocked a single person.?
Earlier this year, Aker Wade announced that it had partnered with Coulomb Technologies, based in Campbell, Calif., to produce a 480-volt,
125-amp public fast charger. Coulomb?s chief executive, Richard Lowenthal, did not expect a large initial market; he said he would be thrilled if the company sold 100 of the approximately $40,000 chargers (which could require a $20,000 installation) in 2011.Mr. Lowenthal said that he did not expect to see fast chargers in gas stations soon, that even a half-hour wait would be too long. ?Gas stations are designed to move cars out in 90 seconds, he said. ?Fast charging isn?t appropriate there.?
A more likely location would be truck stops along interstates, he said. ?If, for instance, you were driving from San Francisco to Los Angeles, you could stop, get a bite to eat, then be on your way.?
But Mark Perry, director of product planning at Nissan North America, said that gas-station charging should be looked at differently. Instead of filling up, he said, drivers might ?pull in, grab a latte from the machine, take care of nature and come back to a car that has now added
25 miles of range.?A five-minute recharge time might speed up the gas station model, but Mr. Lowenthal said that cell chemistry made that speed unlikely anytime soon. Best Buy recently announced that it would offer E.V. charging at some locations, the first big box to make such a commitment in recent times. (Costco installed some chargers in the 1990s.)
According to Rick Rommel, a Best Buy senior vice president for emerging business, the company planned to offer primarily Level 2 charging, but it might have Level 3 at some stores. Mr. Rommel said that the chain envisions consumers briefly topping off their cars using a Level 2 charger, not necessarily going from almost empty to full.
?Level 3 is optimal for consumers who have something else to do for 20 to 30 minutes while waiting for their cars to recharge,? he said.
The high initial cost of fast chargers is an issue, Mr. Rommel said, especially if they needed to be staffed. ?We?re hearing $50,000 for the chargers, and when you add the cost of an attendant to that, it really gets challenging,? he said.
The degradation of battery packs from repeated fast charging is an issue, but some in the industry say they believe enough safeguards are in place.
The Nissan Leaf will have an eight-year, 100,000-mile warranty on its battery pack, and Mr. Perry of Nissan said that while there was a detrimental effect from fast charging, it wasn?t large. ?If you do it only once a day or once a week, there will be very little impact,? he said.
Nissan?s charging partner in the United States is AeroVironment of Monrovia, Calif., which like Aker Wade has long experience with rapid charging of forklifts and airport vehicles. According to Kristen Hensel, an AeroVironment vice president, ?The car is in control, and it will ask for the power it needs.?
Mr. Taylor of Aker Wade adds, ?The charger is a slave to the vehicle?s computer, which understands the battery conditions and how much it can take on without damage.?
AeroVironment is also cooperating with Think, the Norwegian E.V. maker, and the partners say they are working on technology that can charge a small Think City vehicle from depleted to an 80 percent charge in 15 minutes.
Rachel Carroll, a vice president of Think?s battery supplier, Ener1, said ?a whole array of solutions,? including thermal management, could be worked into battery design and control systems to adapt for frequent fast charging. ?If these design solutions are not built into the battery systems from the outset,? she said in a statement, ?fast charging runs the risk of degrading battery life to the point where it becomes difficult to meet the warranty requirements that customers expect.?