Electrically Powered Ultralight Aircraft

On Wed, 15 Aug 2007 12:23:00 GMT, CanalBuilder
wrote in
:

How much of a fire hazard would a paper battery be?

http://www.energy-daily.com/reports/...per _999.html

That is an interesting device indeed. Given these quotes from the
article:

Rensselaer researchers infused this paper with aligned carbon
nanotubes, which give the device its black color. The nanotubes
act as electrodes and allow the storage devices to conduct
electricity. The device, engineered to function as both a
lithium-ion battery and a supercapacitor, can provide the long,
steady power output comparable to a conventional battery, as well
as a supercapacitor's quick burst of high energy. ...

Along with use in small handheld electronics, the paper batteries'
light weight could make them ideal for use in automobiles,
aircraft, and even boats. The paper also could be molded into
different shapes, such as a car door, which would enable important
new engineering innovations.

"Plus, because of the high paper content and lack of toxic
chemicals, it's environmentally safe," Shaijumon said. ...

"Plus, because of the high paper content and lack of toxic
chemicals, it's environmentally safe," Shaijumon said.

"It's a way to power a small device such as a pacemaker without
introducing any harsh chemicals - such as the kind that are
typically found in batteries - into the body," Pushparaj said.

I find the article to be somewhat contradictory in its characterizing
a lithium-ion battery as containing no harsh chemicals. And its claim
of using carbon electrodes in a supercapacitor seem very
counterintuitive for a low impedance device. It reads like an April
Fools Day hoax.

On Aug 15, 8:18 am, Larry Dighera wrote:
On Wed, 15 Aug 2007 12:23:00 GMT, CanalBuilder
wrote in
:

How much of a fire hazard would a paper battery be?

http://www.energy-daily.com/reports/...oring_Power_In...

That is an interesting device indeed. Given these quotes from the
article:

Rensselaer researchers infused this paper with aligned carbon
nanotubes, which give the device its black color. The nanotubes
act as electrodes and allow the storage devices to conduct
electricity. The device, engineered to function as both a
lithium-ion battery and a supercapacitor, can provide the long,
steady power output comparable to a conventional battery, as well
as a supercapacitor's quick burst of high energy. ...

Along with use in small handheld electronics, the paper batteries'
light weight could make them ideal for use in automobiles,
aircraft, and even boats. The paper also could be molded into
different shapes, such as a car door, which would enable important
new engineering innovations.


IF these can be made practical, they sound ideal for use in an
airplane. They are light, and they can be shaped in just about any
way to fit inside the airframe. Suppose they were integrated into the
airframe and wings such that a large percentage of the airplane
consisted of battery. It might be possible to get enough capacity
there for a practical general aviation electric plane.

On Fri, 17 Aug 2007 11:28:06 -0700, Phil wrote
in .com:

It might be possible to get enough capacity
there for a practical general aviation electric plane.

It might indeed. But I'd have to know more about the paper battery
specifications before I could render any sort of judgment. I guess
we'll have to wait until more information is disclosed. Let's see
.....



http://www.eetimes.com/news/semi/rss...etimes_semiRSS

Paper battery is rechargeable

R. Colin Johnson
EE Times
(08/14/2007 9:42 AM EDT)

PORTLAND, Ore. — Rensselaer Polytechnic Institute researchers
said they have developed a paper-thin battery by immersing a
carpet of vertical nanotubes in an ionic liquid electrolyte. The
result is a cellulose paper that stores electrical energy.

The RPI team produced a supercapacitor by placing a second
nanotube electrode on the other side of the paper. They then added
a lithium electrode atop the paper, creating what they claim is a
paper-thin rechargeable battery.

"The carbon nanotubes are embedded in the paper, and the
electrolyte is soaked into the paper, so it really looks, feels
and weighs about the same as paper," said RPI professor Robert
Linhardt.

The supercapcitor and rechargeable battery are the result of a
year and half of collaborative research among three RPI labs. One
lab was making carbon nanotube-based structures, which were
adapted to serve as a battery electrode. By growing the nanotubes
vertically on a sheet, liquid cellulose was poured between the
"forest of nanotubes" to form the battery. Another lab added a
lithium-based top electrode to create either a rechargeable
battery
or a supercapacitor by adding a second nanotube electrode.

Ionic liquids first dissolved the cellulose, turning it into a
gel.
The fluids also serve as the battery electrolyte, carrying ions
from one side of the paper battery to the other.

Each sheet of battery-paper generated about 2.4 volts with a power
density of about 0.6 milliamps/cm2. For higher voltages, paper can
be stacked. For more current, the sheets can be expanded to larger
areas. The battery-paper operates from minus 100 degrees up to 300
degrees Fahrenheit, and can deliver quick surges of current, the
RPI researchers claim. It can also be rolled twisted or cut into
many shapes.

So far, the RPI researchers have only cycled their paper batteries
through 100 rechargings. But they claim no deterioration in
performance has been detected after recharging. Next, they plan
long-term testing of the batteries to determine the maximum number
of rechargings, and to optimize the design for higher power
densities. ...



http://www.uberreview.com/2007/08/fl...-institute.htm
It does not function better than existing batteries on the market
and at present it is extremely expensive to produce.


http://news.rpi.edu/update.do?artcenterkey=2280
Contact: Michael Mullaney
Phone: (518) 276-6161
E-mail:

“We’re not putting pieces together – it’s a single, integrated
device,” he said. “The components are molecularly attached to each
other: the carbon nanotube print is embedded in the paper, and the
electrolyte is soaked into the paper. The end result is a device
that looks, feels, and weighs the same as paper.”




Can someone make the necessary conversions to compare the power
density of about 0.6 milliamps/cm2 for the paper battery to secondary
lithium-ion Polymer batteries at 130 - 1200 Wh/kg*?



* http://xtronics.com/reference/energy_density.htm

The original paper battery article is available on-line:

http://www.pnas.org/cgi/content/abst...urcetype=HWCIT
Proceedings of the National Academy of Sciences of the United States
of America

Published online before print August 15, 2007
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0706508104


This Article

Full Text (PDF)
Articles by Pushparaj, V. L.
Articles by Ajayan, P. M.


Engineering
Flexible energy storage devices based on nanocomposite paper

To whom correspondence should be addressed.

Pulickel M. Ajayan, E-mail:

"Phil" wrote

IF these can be made practical, they sound ideal for use in an
airplane. They are light, and they can be shaped in just about any
way to fit inside the airframe. Suppose they were integrated into the
airframe and wings such that a large percentage of the airplane
consisted of battery. It might be possible to get enough capacity
there for a practical general aviation electric plane.

I can see the headlines, now.

Plane (or car) crashes, and the car's structure electrocutes the occupants.
g
--
Jim in NC

Morgans wrote:
"Phil" wrote

IF these can be made practical, they sound ideal for use in an
airplane. They are light, and they can be shaped in just about any
way to fit inside the airframe. Suppose they were integrated into the
airframe and wings such that a large percentage of the airplane
consisted of battery. It might be possible to get enough capacity
there for a practical general aviation electric plane.


I can see the headlines, now.

Plane (or car) crashes, and the car's structure electrocutes the occupants.
g

LOL!

These paper batterise are light because they are so small.

By the time they make a battery will a few megawatts capacity, it's NOT
going to be all that light.

Lighter than Lead/Acid? Probably.

But light enough to fly? It might be a while...

On Aug 17, 2:19 pm, "Morgans" wrote:
"Phil" wrote

IF these can be made practical, they sound ideal for use in an
airplane. They are light, and they can be shaped in just about any
way to fit inside the airframe. Suppose they were integrated into the
airframe and wings such that a large percentage of the airplane
consisted of battery. It might be possible to get enough capacity
there for a practical general aviation electric plane.

I can see the headlines, now.

Plane (or car) crashes, and the car's structure electrocutes the occupants.
g
--
Jim in NC

I know you're only half serious, but yes, that would have to be
considered. That's a risk in hybrid autos as well. EMTs and
firefighters are taking special training to handle the wrecks of these
cars. And the gasoline we use for our current airplanes poses the
risk of incinerating the occupants in a crash. I am not sure that an
electric plane would actually pose more risk. I would think that the
increased reliability of the propulsion system would decrease the risk
overall. How many people are killed every year in crashes caused by
engine failures?

"Phil" wrote

I know you're only half serious,

Yep, only half, until you really start to think about it.

but yes, that would have to be
considered. That's a risk in hybrid autos as well. EMTs and
firefighters are taking special training to handle the wrecks of these
cars. And the gasoline we use for our current airplanes poses the
risk of incinerating the occupants in a crash. I am not sure that an
electric plane would actually pose more risk.

I think there is a higher risk, perhaps by many times.

Ever seen a LiPo Battery have a catestrophic failure? One of the primary
ways a LiPo can be caused to fail in that way is physical damage. Ask the
electric RC guys. Most of them would never think of putting even a slightly
physically damaged LiPo back into service, unless it was a really cheap
plane that they wanted to see destroyed.

Now imagine a battery many thousands (or even a few hundred) times larger,
and larger capacity to match.

I'll take my chances with the gasoline fire, thanks, ANY day. That speaks
nothing of the chance of electrocution, or chemical burns or injury due to
the cell's chemestry.

I would think that the
increased reliability of the propulsion system would decrease the risk
overall. How many people are killed every year in crashes caused by
engine failures?

How much more reliable is an electric of that size ( to run a decent sized
airplane with decent performance) and power going to be, especially if it is
designed with lightness as a major design consideration? That remains yet
to be seen.

OK, even if we give the electric a given reliability superiority, that is
not going to save all that many lives. Most power failures in I.C. powered
airplanes are not that big of deal, and many times never even reported. Far
more die due to stupid pilot tricks (a broad spectrum category to lump a
bunch of other things together) than loss of power.

Nope, lots of problems to consider before we start considering an electric
aircraft. Lots more than we can maybe even consider, at the moment, even if
we were to figure out a way to make a practical airplane electric powered,
don't you think?
--
Jim in NC

On Aug 18, 12:24 am, "Morgans" wrote:

Nope, lots of problems to consider before we start considering an electric
aircraft. Lots more than we can maybe even consider, at the moment, even if
we were to figure out a way to make a practical airplane electric powered,
don't you think?
--
Jim in NC

Oh, definitely. We are nowhere near a practical electric airplane.
But I think the potential is there (no pun intended), and I hope they
keep working on it.