Supercapacitor "battery" could lead to instant cha

SLAM: debunk creationism, pseudoscience, and superstitions. Discuss logic and morality.

Moderator: Alyrium Denryle

Post Reply
User avatar
The Grim Squeaker
Emperor's Hand
Posts: 10315
Joined: 2005-06-01 01:44am
Location: A different time-space Continuum
Contact:

Supercapacitor "battery" could lead to instant cha

Post by The Grim Squeaker »

Ars wrote:Supercapacitor "battery" could lead to instant charging, long charge life


The batteries we rely on for everything from our cars to our cell phones use a chemical reaction to store and release an electrical charge. The chemicals involved force a large number of tradeoffs in terms of practical considerations, such as weight, toxicity, heat, and the slow charging process.
News is filtering out that a small startup company in Texas has made a breakthrough in charge storage that relies on a completely different technology: capacitors. Details are scarce, but a company that has licensed the technology suggests that it's ready for large-scale production.

For those of you who don't remember high school physics, a capacitor stores charge by arranging two metal plates in parallel. Placing a negative charge in one of the plates will repel electrons from its opposite; this charge difference will be maintained as long as the two plates remain electrically isolated and can be harnessed to produce a useful electric current. A key advantage of capacitors is that they can store charge just as quickly as it's supplied—the long charge times needed by chemical batteries are simply unnecessary. With no chemical reactions involved, capacitors should also have an indefinite life span.

These features may lead you to wonder why everything isn't running on capacitors.
The primary limit to the amount of electrical charge that can be stored in a capacitor is the amount of insulation between the plates, which prevents a current from jumping directly between them.
Existing insulators simply aren't good enough to support a charge density comparable to chemical batteries. In short, capacitors with a sufficient charge capacity take up far too much space.

The Texas company behind the apparent breakthrough, EEStor, is primarily notable for two things: its secrecy (it doesn't even have a web site to link to) and a patent application that describes a process for manufacturing a well-insulated capacitor.
It apparently relies on barium titanate (BaTiO3) as an insulator, something that's been tried in the academic world. But line eight of the patent application suggests that the charge storage is much higher than anything achieved in an academic lab: 52 kilowatt-hours in a 2,000 cubic inch capacitor array. A rough conversion calculation suggests that this is over 10 times the power density of standard lead-acid batteries.

Is this sort of breakthrough realistic? In the absence of an actual product, it's easy to dismiss patent claims as hyperbole.
But the Associated Press is reporting that the ZENN Motor Company, which makes compact electric cars, plans to start using the capacitors before the year is out. The company has invested in EEStar in return for production goals being met and so is in a position to know how realistic its claims are. EEStor is also led by personnel from IBM, which has a strong materials science research presence and has attracted the backing of a tech-savvy investment capital firm. Still, the AP report quotes a number of researchers in the field as being extremely skeptical. One noted that the charge density claims of the patent would represent a 400-fold improvement over existing technology.

Given ZENN Motor's plans, we shouldn't have long to wait before finding out how realistic the patent's statements are. If EEStor's claims pan out, the resulting cars could be charged as quickly and conveniently as filling a gas tank. Until that product is released, however, the skeptics have ample reason to question these claims.
Side note - the high tech investing company they refer to also put early cash into Amazon among others, they have a reputation for putting cash early on into game changers. (They've invested 3 million so far).

I remain very, very skeptical, especially with nothing peer-reviewed or hearing more about the patient, but we'll see within a year. (And someone will be crying or laughing all the way to the bank).
Photography
Genius is always allowed some leeway, once the hammer has been pried from its hands and the blood has been cleaned up.
To improve is to change; to be perfect is to change often.
User avatar
sketerpot
Jedi Council Member
Posts: 1723
Joined: 2004-03-06 12:40pm
Location: San Francisco

Post by sketerpot »

One problem with supercapacitors that I didn't see discussed is their voltage-discharge curve. Regular batteries keep their terminal voltage pretty close to constant until they start to seriously run out of juice. In a capacitor the terminal voltage is proportional to the square root of the amount of energy stored:

E = 1/2*C*V^2, where E is energy, C is capacitance, and V is terminal voltage.

Supercapacitors increase the capacitance C, and the maximum voltage. They do this by increasing the surface area of the plates and getting insulators which can handle more voltage and which have a higher dielectric permittivity. This doesn't change the fundamental nature of what they are: capacitors.

There are voltage regulators which can provide a decently steady output voltage, but this does require extra space and complexity. The simplest ones I've used were about 2x2x1 cm, and cost about $10. This will either have to be built into the supercapacitors or devices powered by them, and either way it kills some of the joy of using magical energy storage devices.

This is still damn cool, though!
User avatar
Sea Skimmer
Yankee Capitalist Air Pirate
Posts: 37390
Joined: 2002-07-03 11:49pm
Location: Passchendaele City, HAB

Post by Sea Skimmer »

I'm pretty sure safety issues are going to keep any kind of capacitor from becoming common for automotive energy storage. Some of the ones we already have can explode with the force of a hand grenade, though the total energy content is even greater.
"This cult of special forces is as sensible as to form a Royal Corps of Tree Climbers and say that no soldier who does not wear its green hat with a bunch of oak leaves stuck in it should be expected to climb a tree"
— Field Marshal William Slim 1956
Howedar
Emperor's Thumb
Posts: 12472
Joined: 2002-07-03 05:06pm
Location: St. Paul, MN

Post by Howedar »

It matters not what kind of magical capacitor it is or could be. Storing that much electrical energy is damned dangerous and there's really no way to physically separate the two electrodes such that damage (ie a crash) couldn't bridge them and brighten everyone's day.

This, children, is why we love chemical fuels.
User avatar
Darth Wong
Sith Lord
Sith Lord
Posts: 70028
Joined: 2002-07-03 12:25am
Location: Toronto, Canada
Contact:

Post by Darth Wong »

This idea was brought up before. Someone tried to defend the safety angle by arguing that they could put voltage regulators on the capacitors, with apparently no regard whatsoever for what might happen if the voltage regulator failed or the car had one of those events which tend to cause failures ... I think we call them "collisions".
Image
"It's not evil for God to do it. Or for someone to do it at God's command."- Jonathan Boyd on baby-killing

"you guys are fascinated with the use of those "rules of logic" to the extent that you don't really want to discussus anything."- GC

"I do not believe Russian Roulette is a stupid act" - Embracer of Darkness

"Viagra commercials appear to save lives" - tharkûn on US health care.

http://www.stardestroyer.net/Mike/RantMode/Blurbs.html
User avatar
Ariphaos
Jedi Council Member
Posts: 1739
Joined: 2005-10-21 02:48am
Location: Twin Cities, MN, USA
Contact:

Post by Ariphaos »

Sea Skimmer wrote:I'm pretty sure safety issues are going to keep any kind of capacitor from becoming common for automotive energy storage. Some of the ones we already have can explode with the force of a hand grenade, though the total energy content is even greater.
We got to play with these giant 25 microfarad capacitors in junior high school. One kid got the bright (har har) idea to stick the electrodes in the outlet. Pity he wasn't injured.
nickolay1
Jedi Knight
Posts: 553
Joined: 2005-05-25 12:42am
Location: Marietta, GA

Post by nickolay1 »

Here's another idea: how about designing them with an equivalent series resistance within the range that it can still supply sufficient current for a motor yet insufficient current to cause an explosion? As an instrinsic property, this won't be something that will cease to be effective if the device is damaged.
User avatar
aerius
Charismatic Cult Leader
Posts: 14799
Joined: 2002-08-18 07:27pm

Post by aerius »

nickolay1 wrote:Here's another idea: how about designing them with an equivalent series resistance within the range that it can still supply sufficient current for a motor yet insufficient current to cause an explosion? As an instrinsic property, this won't be something that will cease to be effective if the device is damaged.
If the ESR is high enough such that the capacitor can't blow up when shorted, it's not going to provide anywhere near enough current to power a car. In other words, can't be done.
Image
aerius: I'll vote for you if you sleep with me. :)
Lusankya: Deal!
Say, do you want it to be a threesome with your wife? Or a foursome with your wife and sister-in-law? I'm up for either. :P
User avatar
Admiral Valdemar
Outside Context Problem
Posts: 31572
Joined: 2002-07-04 07:17pm
Location: UK

Post by Admiral Valdemar »

Here's a crazy suggestion. Because chemical batteries suck shit and raw electric charge in a capacitor is a ticking time bomb, why not go for the new flywheels? The damn things are safe enough, can charge quick and easily and can store far more charge than any standard power cell.

We seem to go straight to dangerous capacitors or compressed air without looking at KE storage mediums.
User avatar
Starglider
Miles Dyson
Posts: 8709
Joined: 2007-04-05 09:44pm
Location: Isle of Dogs
Contact:

Post by Starglider »

sketerpot wrote:One problem with supercapacitors that I didn't see discussed is their voltage-discharge curve. Regular batteries keep their terminal voltage pretty close to constant until they start to seriously run out of juice. In a capacitor the terminal voltage is proportional to the square root of the amount of energy stored
I imagine this can be overcome with sufficiently sophisticated motor controllers, which lengthen pulse durations as the voltage falls, as well as running coil elements in series to start with but switching to parallel as the voltage drops. A voltage regulator will still be required for the accessories, but the capacitor pack will probably be high voltage so a simple switching regulator should work fine.
why not go for the new flywheels? The damn things are safe enough
If the casing is penetrated or the bearing fails, they dump their energy just as well as a capacitor bank does, and have a higher tendency to produce dangerous shrapnel in an accident. Practical applications require armoured housings just as I expect this capacitor solution will.
We seem to go straight to dangerous capacitors or compressed air without looking at KE storage mediums.
Oh they've been looked at but even with the best available materials they can't store anything like as much energy as even compressed air, never mind gasoline. If they could store as much energy they would be at least as dangerous, possibly more.
aerius wrote:If the ESR is high enough such that the capacitor can't blow up when shorted, it's not going to provide anywhere near enough current to power a car. In other words, can't be done.
No but you could and probably should integrate plenty of fusible links into the capacitor pack.
User avatar
Admiral Valdemar
Outside Context Problem
Posts: 31572
Joined: 2002-07-04 07:17pm
Location: UK

Post by Admiral Valdemar »

Starglider wrote:
If the casing is penetrated or the bearing fails, they dump their energy just as well as a capacitor bank does, and have a higher tendency to produce dangerous shrapnel in an accident. Practical applications require armoured housings just as I expect this capacitor solution will.
The designs I refer too are proofed against that eventuality, which is pretty common in automobiles and was one reason they didn't catch on decades ago (that and the "Why bother? We have cheap fuel"). The flywheel itself is simply a wrapped coil of high-density polymer that, should the bearing snap or the casing be lacerated, unfurls inside the compartment and halts itself without becoming a massive frag grenade. The energy is dissipated violently, just in a confined space, which is, to my mind, a nicer thing to have than petroleum fires/explosions or capacitor short circuits.
User avatar
Starglider
Miles Dyson
Posts: 8709
Joined: 2007-04-05 09:44pm
Location: Isle of Dogs
Contact:

Post by Starglider »

Admiral Valdemar wrote:The energy is dissipated violently, just in a confined space, which is, to my mind, a nicer thing to have than petroleum fires/explosions or capacitor short circuits.
All of the stored energy is turning into heat, applied to the flywheel remains and the casing. With a capacitor short all of the stored energy is turning into... guess what... heat! The only difference is that initially the heat is all applied to the capacitor internals, not the casing, but I don't think that'll make much difference. You need a reinforced housing either way.
User avatar
Admiral Valdemar
Outside Context Problem
Posts: 31572
Joined: 2002-07-04 07:17pm
Location: UK

Post by Admiral Valdemar »

You still need a reinforced housing, but these flywheels didn't do anything but get hot and unwind. They were even reused after a simulated catastrophic failure. There are other kinds that simply turn into a load of hot sand in the container, however, the advantage of the new types for future use is that they require far less shielding than anything before and are highly durable.
User avatar
Fingolfin_Noldor
Emperor's Hand
Posts: 11834
Joined: 2006-05-15 10:36am
Location: At the Helm of the HAB Star Dreadnaught Star Fist

Post by Fingolfin_Noldor »

How does this differ from those large capacitors soaked in oil I have heard about aside from size? Those capacitors, not just high in capacitance, are extremely dangerous and extremely magnetizing.
Image
STGOD: Byzantine Empire
Your spirit, diseased as it is, refuses to allow you to give up, no matter what threats you face... and whatever wreckage you leave behind you.
Kreia
User avatar
Enola Straight
Jedi Knight
Posts: 793
Joined: 2002-12-04 11:01pm
Location: Somers Point, NJ

Post by Enola Straight »

These flywheels being talked about...they are Magnetic Flywheels, right?
http://www.imdb.com/title/tt0060396/

Spinning in a high vaccuum on magnetic bearings, energy losses due to friction is eliminated.

Unfortunately, this is not well adapted to automotive use, as cornering Gs and bumps in the road causes the rotor to "land" on the bearings and thus lose energy.

Compared to regular batteries and capacitors, what is the voltage-discharge curve like?

Kilowatt-hour per kilogram?

Some other benchmark of efficiency?
Masochist to Sadist: "Hurt me."
Sadist to Masochist: "No."
User avatar
Resinence
Jedi Knight
Posts: 847
Joined: 2006-05-06 08:00am
Location: Australia

Post by Resinence »

Enola Straight wrote:These flywheels being talked about...they are Magnetic Flywheels, right?
http://www.imdb.com/title/tt0060396/

Spinning in a high vaccuum on magnetic bearings, energy losses due to friction is eliminated.

Unfortunately, this is not well adapted to automotive use, as cornering Gs and bumps in the road causes the rotor to "land" on the bearings and thus lose energy.

Compared to regular batteries and capacitors, what is the voltage-discharge curve like?

Kilowatt-hour per kilogram?

Some other benchmark of efficiency?
I'd say he's referring to the NASA Flywheel Design that can survive somewhat strong g-forces without landing on the bearings and during a catastrophic failure simply unfurls inside the casing.
“Most people are other people. Their thoughts are someone else's opinions, their lives a mimicry, their passions a quotation.” - Oscar Wilde.
User avatar
aerius
Charismatic Cult Leader
Posts: 14799
Joined: 2002-08-18 07:27pm

Post by aerius »

Fingolfin_Noldor wrote:How does this differ from those large capacitors soaked in oil I have heard about aside from size? Those capacitors, not just high in capacitance, are extremely dangerous and extremely magnetizing.
Those are high voltage capacitors, the oil is there to prevent corona and arcing from the kilovolt range voltages involved. In terms of actual capacitance, it's not that high, usually a few dozen microfarads at most unless it's the size of a garbage can. Fairly low energy density too, but due to their construction they have very low ESR and can discharge all that energy in a real hurry.
Image
aerius: I'll vote for you if you sleep with me. :)
Lusankya: Deal!
Say, do you want it to be a threesome with your wife? Or a foursome with your wife and sister-in-law? I'm up for either. :P
User avatar
Starglider
Miles Dyson
Posts: 8709
Joined: 2007-04-05 09:44pm
Location: Isle of Dogs
Contact:

Post by Starglider »

aerius wrote:In terms of actual capacitance, it's not that high, usually a few dozen microfarads at most unless it's the size of a garbage can.
Note that low voltage electrolytics can do much better; you can buy a one Farad capacitor, rated at 15v with a superfluous LED voltage display for $50+tax (much cheaper wholesale). It's about the size of a 1 litre drink bottle.
Marko Dash
Jedi Knight
Posts: 719
Joined: 2006-01-29 03:42am
Location: south carolina, USA
Contact:

Post by Marko Dash »

Maybe I'm thinking of something else, but i always thought capacitors charged slowly but dumped all at once? this seems to do the opposite.
If a black-hawk flies over a light show and is not harmed, does that make it immune to lasers?
User avatar
sketerpot
Jedi Council Member
Posts: 1723
Joined: 2004-03-06 12:40pm
Location: San Francisco

Post by sketerpot »

Marko Dash wrote:Maybe I'm thinking of something else, but i always thought capacitors charged slowly but dumped all at once? this seems to do the opposite.
No, here are pictures of what they actually do. Charging:

Image

Discharging:

Image

Of course, it gets more complicated when you're giving them something other than step functions. Just remember, i = C dv/dt.
User avatar
Pu-239
Sith Marauder
Posts: 4727
Joined: 2002-10-21 08:44am
Location: Fake Virginia

Post by Pu-239 »

What about their use in laptops? One of my biggest annoyance w/ laptops is the batteries wear down after awhile...

Of course, the laptop manufacturers do make money off of replacement batteries, supercapacitors probably cost more than replacement batteries over the lifetime of the laptop, and the safety angle.

ah.....the path to happiness is revision of dreams and not fulfillment... -SWPIGWANG
Sufficient Googling is indistinguishable from knowledge -somebody
Anything worth the cost of a missile, which can be located on the battlefield, will be shot at with missiles. If the US military is involved, then things, which are not worth the cost if a missile will also be shot at with missiles. -Sea Skimmer


George Bush makes freedom sound like a giant robot that breaks down a lot. -Darth Raptor
Post Reply