OT: interesting article about ultracapacitors
- From: TheBenevolentUniversePremise@xxxxxxxxx
- Date: 12 Feb 2006 11:47:27 -0800
http://www.terradaily.com/reports/MIT_Researchers_Fired_Up_About_Battery_Alternative.html
ENERGY TECH
MIT Researchers Fired Up About Battery Alternative
-
by Staff Writers
Cambridge MA (SPX) Feb 08, 2006
Just about everything that runs on batteries -- flashlights, cell
phones, electric cars, missile-guidance systems -- would be improved
with a better energy supply. But traditional batteries haven't
progressed far beyond the basic design developed by Alessandro Volta in
the 19th century.
Work at MIT's Laboratory for Electromagnetic and Electronic Systems
(LEES) holds out the promise of the first technologically significant
and economically viable alternative to conventional batteries in more
than 200 years.
Joel E. Schindall, the Bernard Gordon Professor of Electrical
Engineering and Computer Science (EECS) and associate director of the
Laboratory for Electromagnetic and Electronic Systems; John G.
Kassakian, EECS professor and director of LEES; and Ph.D. candidate
Riccardo Signorelli are using nanotube structures to improve on an
energy storage device called an ultracapacitor.
Capacitors store energy as an electrical field, making them more
efficient than standard batteries, which get their energy from chemical
reactions. Ultracapacitors are capacitor-based storage cells that
provide quick, massive bursts of instant energy. They are sometimes
used in fuel-cell vehicles to provide an extra burst for accelerating
into traffic and climbing hills.
However, ultracapacitors need to be much larger than batteries to hold
the same charge.
The LEES invention would increase the storage capacity of existing
commercial ultracapacitors by storing electrical fields at the atomic
level.
Although ultracapacitors have been around since the 1960s, they are
relatively expensive and only recently began being manufactured in
sufficient quantities to become cost-competitive. Today you can find
ultracapacitors in a range of electronic devices, from computers to
cars.
However, despite their inherent advantages -- a 10-year-plus lifetime,
indifference to temperature change, high immunity to shock and
vibration and high charging and discharging efficiency -- physical
constraints on electrode surface area and spacing have limited
ultracapacitors to an energy storage capacity around 25 times less than
a similarly sized lithium-ion battery.
The LEES ultracapacitor has the capacity to overcome this energy
limitation by using vertically aligned, single-wall carbon nanotubes --
one thirty-thousandth the diameter of a human hair and 100,000 times as
long as they are wide. How does it work? Storage capacity in an
ultracapacitor is proportional to the surface area of the electrodes.
Today's ultracapacitors use electrodes made of activated carbon, which
is extremely porous and therefore has a very large surface area.
However, the pores in the carbon are irregular in size and shape, which
reduces efficiency. The vertically aligned nanotubes in the LEES
ultracapacitor have a regular shape, and a size that is only several
atomic diameters in width. The result is a significantly more effective
surface area, which equates to significantly increased storage
capacity.
The new nanotube-enhanced ultracapacitors could be made in any of the
sizes currently available and be produced using conventional
technology.
"This configuration has the potential to maintain and even improve the
high performance characteristics of ultracapacitors while providing
energy storage densities comparable to batteries," Schindall said.
"Nanotube-enhanced ultracapacitors would combine the long life and high
power characteristics of a commercial ultracapacitor with the higher
energy storage density normally available only from a chemical
battery."
This work was presented at the 15th International Seminar on Double
Layer Capacitors and Hybrid Energy Storage Devices in Deerfield Beach,
Fla., in December 2005. The work has been funded in part by the
MIT/Industry Consortium on Advanced Automotive Electrical/Electronic
Components and Systems and in part by a grant from the Ford-MIT
Alliance.
.
- Prev by Date: Re: used Allen and Heath CMC24 - worth buying?
- Next by Date: Re: DAD vs. DDD production
- Previous by thread: FA Yamaha NS-1000 crossover 5863542453
- Next by thread: FS on eBay: M-Audio CO2 S/PDIF Converter
- Index(es):
Relevant Pages
|
