Potential Energy

Kevin Bullis is Technology Review’s energy editor.
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- Cheap...
: I think this is so true, Electric vehicles are a great idea, but like most new advances in tech,...
- RD
: No. Cap & Trade taxes Americans for energy use and redistributes it to political supporters like...
- RD
: Those you call AGW, ARE in favor of nuclear energy. It's the Progressives who have been blocking...
- RD
: CO2 isn't the problem. In Maryland, a new study in the International Journal of Climatology – by...
- kstauff
: The only agreement I recall us not upholding recently is the ABM treaty, for which we informed...
- kstauff
: Kevin: You're either unaware or glossing over recent history. The House climate bill BARELY...
- cheadrick
: Where did that 1% number come from? There have been no accurate measurements of atmospheric CO2...
- colinnwn
: "We fly planes so much that on 9/11 global temperatures dropped a large amount more than usual as...
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: Is this the same climate treaty I heard about that calls for the industrialized nations to pay...
- devassocx
: I for one, welcome failure of such an ill-conceived and costly(for no reason) piece of...
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Thursday, October 15, 2009
Flow Batteries For Fast Electric Car Charging
New batteries could make recharging EVs much faster.
By Kevin Bullis
Electric vehicles can take hours to recharge, making cross-country road trips a challenge. But researchers at the Fraunhofer Institute for Chemical Technology in Germany say they've got a potential solution: flow batteries.
This type of battery uses two electrolytes rather than the solid electrodes used in lithium ion batteries. Recharging them is as fast as pumping out depleted electrolytes and replacing them with fresh ones--it wouldn't take longer than refilling a gas tank. One of the problems with flow batteries, though, has been that they only store about a quarter of the energy as lithium ion batteries--you'd have to recharge a lot, making them impractical. The Fraunhofer researchers say they've improved the energy storage to match lithium ion batteries--still not as good as with gasoline, but a great improvement. Some lithium ion EVs get over 200 miles on a charge.
But here's the catch: one of the reasons hydrogen fuel cell vehicles have come under fire recently is that you need to install a large infrastructure for distributing and dispensing hydrogen. A flow battery system would have a similar problem. You'd need to install special refueling stations where the spend electrolytes can be recharged and dispensed.
Monday, August 03, 2009
Nissan Reveals "Leaf" Electric Car for 2010
Will the vehicle's short range hamper its success?
By Kevin Bullis
Last
week Nissan showed off the battery and
drivetrain platform for its upcoming electric vehicle. Now it's revealed the car itself--the Leaf.
This
zero-emissions vehicle, which has a range of 100 miles on a charge, will go on
sale next year in Japan, the United States, and Europe. It will be powered by a
lithium manganese battery developed in a joint venture between Nissan and NEC.
Manganese-based lithium ion batteries are popular with automakers (GM plans to
use one in the Volt) because they're more stable than the cobalt oxide
batteries commonly used in laptops and other portable electronics.
Nissan
is taking a markedly different strategy than companies such as Toyota, GM, and
Chrysler, which have emphasized hybrid vehicles that can run on both
electricity and gasoline. Even the Volt, which GM is describing as an electric
vehicle, has an onboard gasoline generator that kicks in after 40 miles of
driving to recharge its battery. Because gasoline stores orders of magnitude
more energy than batteries, such vehicles can have longer range than pure
battery electric vehicles like Nissan's Leaf. What's more, fuel tanks can be
refilled much faster than batteries can be recharged, at least without special
electrical connections, making long-distance road trips easier. (Electric
vehicle enthusiasts like to brag about cross-country trips, but these require
careful planning--it's good to find RV parks equipped with 220-volt
outlets--and a willingness to take frequent breaks while the car charges.)
Nissan
has been working with a company called Better Place on a strategy for extending
the range of EVs. The idea is to build battery swap stations along major
highways. Drive in and a simple robot takes out your car's depleted battery and
inserts a charged one, and you're quickly on your way again. Nissan demonstrated one version of a swap station in May.
But
it wasn't immediately clear whether the Leaf would be compatible with swap
stations. A spokesperson for Nissan said that the company doesn't plan to use a
swap strategy in the United States, but she expects the Leaf could be used with
swap stations in other countries. She said she'd get back to me to confirm. (If
she does, I'll add that here.)
Many
EV supporters say it doesn't make sense to buy a car with a gasoline engine and
fuel tank as well as an electric motor and battery pack. After all, most of the
time either one or the other is just dead weight, sitting there unused. They
say, if you commute less than 80 miles each day, buy an EV. Then, for those
relatively rare occasions when a longer range is required, rent a car. Or use
the EV as a second vehicle.
But
one of the most expensive parts of an EV is the battery, and most people
actually commute less than 40 miles a day. If you can make do with a battery
pack half the size, you could save money, even with the added cost of a
gasoline generator. So either strategy--pure EV or hybrid--could make sense.
Monday, July 27, 2009
Nissan Unveils an Electric-Vehicle Platform
The prototype electric-drive system is built into one of the company's existing vehicles.
By Kevin Bullis
Today
in Tokyo,
Nissan showed off a prototype of its
electric-vehicle battery platform
incorporated into one of its existing vehicles, the Tiida.
The
platform will be incorporated into a new vehicle body that will be unveiled at
the beginning of August. It consists of a highly rigid body (designed to reduce
vibrations and increase the car's durability), an electric motor, and a
lithium-ion battery pack built into the floor of the car so that it doesn't eat
into cargo space. The production version of the vehicle will go on sale next
year, the company says, and get 160 kilometers--100 miles--on a charge.
That
short range could be one reason why the company is also marketing a new
"EV-IT" system, equipping the electric vehicle with information-technology
features to allay range anxiety. These include a map that shows the maximum
distance the car can drive based on its current state of charge, as well as the
locations of charging stations within reach. The system can also be set so that
the vehicle charges at night, which could save people money if utilities start
charging rates that vary by the time of day. The system also can send a message
to the driver's cell phone when charging is complete.
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