Slashdot Mirror
Advance In Super/Ultra Capacitor Tech: High Voltage and High Capacity
fyngyrz writes: Ultracaps offer significantly faster charge and discharge rates as well as considerably longer life than batteries. Where they have uniformly fallen short is in the amount of energy they can store as compared to a battery, and also the engineering backflips required to get higher voltages (which is the key to higher energy storage because the energy stored in a cap scales with the square of the cap's voltage, whereas doubling the cap's actual capacitance only doubles the energy, or in other words, the energy increase is linear.) This new development addresses these shortcomings all at once: considerably higher voltage, smaller size, higher capacitance, and to top it off, utilizes less corrosive internals. The best news of all: This new technology looks to be easy, even trivial, to manufacture, and uses inexpensive materials — and that is something neither batteries or previous types of ultracaps have been able to claim. After the debacle of EEStor's claims and failure to meet them for so long, and the somewhat related very slow advance of other ultracap technology, it's difficult not to be cynical. But if you read TFA (yes, I know, but perhaps you'll do it anyway) you may decide some optimism might actually be called for.
We're getting to a point where the issue isn't just how much energy we can store in how little space, and how readily we can use it, but also how stable that medium is and how gracefully it fails when mishandled. Cellphone batteries are already pretty scary when punctured, imagine something holding several times as much energy.
A bullet may have your name on it but splash damage is addressed "To whom it may concern."
Capacitors. [...] If they finally obeyed Moore’s Law by squeezing themselves down to the microscale
They never disobeyed Moore's law since Moore's law is about transistor density..
CLI paste? paste.pr0.tips!
You said it. We want a lot of energy in a hand-held format. But it's dangerous.
That energy will get hacked for purposes both good and bad, and the bad purposes will include explosions.
-kgj
What's not to like?
The DVD-burner graphene etching technique to produce supercaps is several years old -- but it looks like they're continuing to work on it. Good to see the technique hasn't been abandoned.
Kythe
High Voltage!
You said it. We want a lot of energy in a hand-held format. But it's dangerous.
Do you have any comprehension of the amount of energy stored in a tank of gasoline? A lot of energy stored is not in and of itself dangerous. What matters is the means by which that energy can be released. Your body stores a huge amount of energy but there is no easy way to release that energy rapidly. Diesel has even more energy than gasoline but good luck igniting it. You can drop a lit match on diesel fuel and nothing will happen. Now do batteries and ultracaps have their own unique failure modes? Sure. But it's not hard to demonstrate that the chances of an explosion are pretty minimal.
That energy will get hacked for purposes both good and bad, and the bad purposes will include explosions.
Do you see a lot of exploding cars outside of fictional movies? Causing an explosion normally requires a criminal act typically involving external explosives. It's not actually a very easy thing to cause an explosion. (thank goodness) In most cases even if there is a catastrophic failure the car merely burns, it doesn't explode. I actually trust the engineers working on this stuff and I've worked with companies building battery packs for cars and other high energy applications over the years. They are pretty well aware of the possible failure modes and what to do about them. Explosions aren't something they are overly worried about.
Why can't we use these things in cars? Imagine being able to recharge your car faster than you could fill it up with gas. The station itself could then recharge their built-in ultra capacitors. Even if it takes X seconds to charge a car and five to ten times longer to charge the station back for that amount, it would be impressive. No more "out of gas", no more having huge-ass semi-trucks filled with thousands of litres of gas driving around. Stations could add solar panels for some additional "free" electricity, etc.
Cellphone batteries are already pretty scary when punctured, imagine something holding several times as much energy.
One of the problems with capacitors charging rapidly is that they can also discharge very rapidly too so any failure would not be graceful. However I'm not sure there is much reason to be optimistic yet for these devices. The article mentions that the way they get high voltages is by connecting the capacitors together. This means they connect them in series which will significantly reduce the actual capacitance since capacitors in series add like resistors in parallel.
Cellphone batteries are already pretty scary when punctured, imagine something holding several times as much energy.
You ARE something that holds several times as much energy. The energy density of animal fat is roughly the same as that of gasoline and both are FAR higher than the energy density of a lithium-ion battery. Whether something is scary has very little to do with the amount of energy it holds. It is the rate and circumstances in which it can be released that matters.
That said, if something hits me hard enough to puncture my cell phone battery while I'm carrying my phone, the battery combustion is probably the least of my concerns. I'm likely much more concerned with whatever just speared or shot me.
The centimeter-scale devices would have capacitances in the range of 400 to 1,000 millifarads
My maths seems off here. Anybody know when they were giving this number if they meant:
- a 1cm x 1cm x 'paper thin' device; or
- a 1cm device?
Google maths (below) suggests a 1 Ah 12v battery is equal to 300F.
1 F = 1 As / V
1 Ah = 3600 As
3600 As / 12V = 300 As/V = 300F
Best case scenario of 1000 millifarads we would need 300cm for a 1 Ah equivalent battery? Seems large....
Also wondering how they deal with the voltage drop? Years back I remember a story about a near constant voltage ultracapacitor - would this use the same technology?
Well, yes, the amount of energy stored goes up as the square of voltage for a given capacitance. However, for a given dielectric getting twice the voltage requires twice the thickness and cuts the charge in half -- so the energy per unit volume is unchanged.
Which shouldn't be surprising since the energy is stored in the dielectric by (e.g.) straining the molecular structure of the material.
The biggest reason for going to higher voltages is to reduce the interconnects, which get enormous at low voltages and high currents. (Cross-sectional area goes up inversely with the square of voltage for any acceptable IR loss, which is why long-distance power lines run at scary voltages.)
Lacking <sarcasm> tags,
One of the problems with capacitors charging rapidly is that they can also discharge very rapidly too so any failure would not be graceful.
That's one of those ideas that sounds right but isn't necessarily actually true. Yes there are ways to rapidly discharge a cap but it doesn't follow that those are failure modes that would be likely. We use capacitors all over the place and most of the failures of them are demonstrably not from catastrophic discharge.
Energy stored is C * V * V / 2. Telling us C without V is sort of like measuring the capacity of a gas tank by giving you the length, but leaving out the depth and width.
They report capacitances in the 1000 millifarads for a "centimeter scale" device.
If the maximum voltage is 1V, then we have an unimpressive energy storage of 0.5 J in their "centimeter scale" device.
AAA batteries can store about 5000 J, by contrast. To match that, these would need to be charged to 100V.
Without the V number this article is disappointingly uninformative.
--PM
Why can't we use these things in cars?
We already do use them in cars.
Imagine being able to recharge your car faster than you could fill it up with gas.
Not quite that simple. There is a serious heat issue to deal with when you are transferring that much electric power over wires even if the power is available. Filling up something like a Tesla safely in less than 3 minutes is not as easy as it sounds. You can't just pump more juice over the same wires. You start getting into needing superconductors to handle the juice unless you have wires the thickness of your arm.
Stations could add solar panels for some additional "free" electricity, etc.
That would be a LOT of solar panels. I'm not sure you appreciate the amount of power we are talking about here. A few solar panels on the roof would add so little power it would barely be measurable.
Anyone thinking Capacitance Gel?
jrjr
High voltage, compact size, easy to make. I'm sure this will somehow be used in porn first (the 'how' eludes me but there seems to be a Rule 34 about tech) - yet "Everything that can be weaponized, will be weaponized..."
Do you have any comprehension of the amount of energy stored in a 3-oz bottle of distilled water?. E=mc^2. If I didn't slip a decimal, the blast radius should run to approximately 6 miles.
Exactly my point. The energy density of a substance is almost irrelevant to the discussion. What matters is whether there is a means to release that energy catastrophically. In most cases there is no easy way to do it. We don't see cell phones detonating. We don't see cars exploding. We don't see laptop batteries going ka-boom. Worst case we normally see is a comparatively gentle and slow combustion. Damaging sure but hardly an explosion.
The idea of having a cheap consumer device that can so easily etch any bitmap with such fine detail intrigues me. I wonder what else you could etch. If there was a coating for circuit boards that these lasers could etch that would be really cool. Pop a board in your CD burner amd minutes later have a perfectly etched board.
OH PLEASE let this become a reality! I've been shying away from an off-grid solar system in my house because I HATE batteries and I don't own an electric car because batteries suck so bad... but THE HOLY GRAIL IN ENERGY STORAGE?? Is it upon us?? If these ultracaps turn out to be real, I wanna charge them with my 3.5kW of solar panels and power my house and (future) vehicle!
As a kid in electronics class out teacher wired up a capacitor incorrectly to demonstrate what would happen if we weren't cautious.
The resulting explosion was surprisingly powerful.
I wonder what an ultra cap would do in the same situation
"If any question why we died, Tell them because our fathers lied."
FTA: "... plummet until microsupercapacitors find their way into camera phones"
How old is this article? If memory serves me correctly, camera phones haven't been used since the last millenium.
I hope this makes railguns more feasible for tank-sized vehicles.
The best they said was
"The centimeter-scale devices would have capacitances in the range of 400 to 1,000 millifarads—easily enough to power an LED flashlight for an hour."
If the flashlight is wimpy, an led with 10mA at 1Volt for an hour is 36J. 36J in 1F is 4.24 Volts.
If the flashlight is bright, an led with 1 Watt for an hour is 3600J. 3600J in 1F is 42.4 volts. That would be interesting.
If they cover cost and power and energy density, the other issue for batteries is longevity.
If they had an electrolyte that worked in this application they wouldn't be talking about all the possible choices. They would tell us what worked.
"For this solid electrolyte, we have plenty of choices. We can use gelled polymer electrolytes, made by swelling a polymer matrix with an electrolyte solution, or we can solidify ionic liquids by adding polymers or silica nanopowder. This nonleaking design, together with a virtually unlimited number of charge and discharge cycles, means that our supermicrocapacitors will likely outlast all other electronic devices on the chip. Such long life will be particularly useful whenever it is inconvenient or dangerous to open things up to replace a power source, as in pacemakers, defibrillators, and other medical implants."
Electrical and magnet fields occur in 3 dimensions, not one. They can talk about the gap between the fingers of their layout, but their effective average gap in 3D is probably closer to PI*center_distance/2 which gives a lesser result for the expected capacitance. Their max voltage with a given electrolyte is limited to the closest edge, but that is not how a physicist would compute expected capacitance.
...except super capacitors are designed to charge/discharge rapidly... so I'm confused as to the point you are making.
Simple version. Failure = easy. Explosion = hard.
An explosion is a difficult thing to do even if you are trying to get one. It requires a rather fussy set of circumstances to be possible. Explosions by accident are exceptionally rare.
Accidental discharge wouldn't result in an explosion per se, but could start fires and would definitely be lethal to someone who discharged a super capacitor accidentally through themselves.
Which is why you design the system to make accidental discharge difficult to achieve. The mechanics of this are well understood. You could easily cause a rapid discharge of a car battery but in practice it isn't a big problem.
Maybe 20 years ago, I knew someone working at GM as an intern on their electric car. I asked about ultra capacitors. He said they tried them but when they did test crashes, 10 foot fireballs shot out of the car. There is a large amount of energy there and explosions are a real problem. So, did they overcome this? Because if not they will not be used in cars for quite some time.
From here
LightScribe doesn't "etch" anything. Using infrared light it reacts with a photoreactive dye. It's the same principle as recording to CDR. You don't "burn" anything when you record a CDR. You just modify a photoreactive dye.
I think something like 4 mWh of solar energy hit the roof of your average gas station a sunny day
Don't know where you got your "data" but that is wrong. One square foot of roof gets about 10-30KWh per YEAR. Even if the roof is 1000 square feet (100x100) that means it will get about 82 KWh per day on a nice sunny day. That isn't even enough to charge one Tesla fully per day. It might offset their costs slightly but it's hardly going to make a huge dent.
Big oil/big money interests will do anything that they can to slow if not stop or suppress or discredit this! As they have been doing for many years with any technology that threatens their profits.
Why do you think that early hybrid (gas engine and battery powered) cars had no provision to plug the car in to charge its battery? That came about because someone smart started marketing a kit for that. Shortly after that it became an option and then came standard on hybrid vehicles.
Development of more efficient batteries and any other technology that could improve electric cars has been slowed or suppressed. Look at the story of the EV1 (see the documentary "Who Killed the Electric Car"). Big oil/Big money interests killed the EV1 because they were afraid that if it became popular, it would lower their profits. Killing the EV1 set the production and adoption of electric vehicles back decades. Just think where electric vehicles could be now if they had become popular in the 90s, how many improvements would have been made by now!
So many things that could have greatly benefited people have been suppressed or destroyed by the greedy just so that they could continue to profit from other's misfortunes. Really sad isn't it?
A while back I wondered if coating a vehicle in solar panels would allow it to run itself.
Short answer is no. There isn't enough solar energy hitting a square foot of ground even on the sunniest of days to power anything remotely the weight of a modern car. I think most places get something like 10-30kwh of solar energy per square foot per year. A Tesla has a 90kwh battery in it. So even if you coated it in perfectly efficient solar cells you wouldn't get more than a few feet.
The use of supercapacitors as storage devices is severely limited by their discharge curve (compared with batteries) - google it.
As TFA explains, they don't have a fundamentally higher voltage capacitor, allowing them to take advantage of CV^2 gains. Rather, their manufacturing technology can build multiple capacitors in series as easily as a single lower-voltage capacitor. But the resultant capacitance is inversely proportional to the square of the number in series (since they're smaller and in series), so there's no energy density gain.
See subject.
The DVD-burner graphene etching technique to produce supercaps is several years old -- but it looks like they're continuing to work on it. Good to see the technique hasn't been abandoned.
I'd never heard of it.
Using a DVD burner for constructing microcircuitry is a GREAT hack. Should be trivial to do resistors and wiring with it. If somebody can figure out how to do fast thin-film transistors it would put microcircuit fabrication within easy reach of hobbiests.
Sure the scale would be far larger than microchips. But for a lot of stuff that's just fine.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
See subject..
We've all been anesthetized by the constant daily 'AMAZING NEW BATTERY TECH AROUND THE CORNER!' articles over the past X years.. but this one doesn't sound like they are doing the 'if only we could do X' to make it work commercially.. these guys even suggest you could start right now with a room full of DVD burners. they even state there's a startup company already started on making the stuff commercially for the market. I for one will remain a bit optimistic on this one...
I don't think we'll see this tech in Tesla's car in the next 5 years, or maybe even in cell phones in that time period. I DO expect we'll see it in stuff like medical gear and in solar panels. That bit where the backside of a solar cell could have a sheet of ultra caps on it capable of storing all the energy it captured...so a meter square of solar panel on a sunny day that could store lets say a kw/hour in itself. That could def be useful. A BIG part of the cost of a home solar system for off-grid is the battery storage. Not to mention the weight and hazard of deep cycle acid cells. Collection and storage in one place, lightweight and maint. free? High voltage transmission to prevent line losses? Oh yah.. I can see this cracking the home solar thing WIDE open, and that's just one industry my tiny little mind can think of.
If I sound stupid, it's not me talking....
RTFA It isn't about making giant capacitors to hold a ton of power. It's about storing power for microelectronics more easily. Replacing car batteries is a problem that can be solved at a later date.
Democracy Now! - your daily, uncensored, corporate-free
1 Capacitors hold charge between two plates separated by the electrolyte, and typically excess electrons accumulate on one conducting plate as a cloud. Once you reach a certain voltage, the insulation fails = punch-through. If self healing, the voltage will fall and the arc will stop before the charge is gone. If not, most of the charge will dissipate.
2 Capacitors are the mechanical analog of the spring, more force = more spring stretches, in the same way as you charge a capacitor the voltage increases as the charge increases. There is not voltage plateau of the the electro-chemical difference. Charge Q = 1/2 C * V * V, with Q = coulombs C = farads, and V = voltage. Not the square function, when voltage drops by half, charge is 75% gone, and vice versa. The voltage falls, so there needs to be a regulator for loads that need a constant voltage.
3. Since all surfaces are in parallel, charge and discharge can be very rapid, limited by path resistance and inductance.
4 Batteries change the chemical state of the charge/discharge compound, as a bulk material. This is inherently 25-100 times as much as a capacitor's charge.
Even these capacitors face these limits.
That said, their speed and near infinite life will find them a role, just where they will fit? My fitbit runs for a week on a capacitor and charges very rapidly. Will an iPad or android pone run on that sort of a tiny charge? It is possible that e-ink devices as book reading displays will get to do this, but devices that transmit RF power use more than 1000 times the power of an e-ink reader in static mode, and 100 time in rewrite mode
There is existing tech that allows light to affect a photosensitive layer on a copper clad board. Do that, wash off the unexposed areas, then submerge the board in chemical etchant. Wait, rinse, dry, and you have a single layer PCB.
Contribute to civilization: ari.aynrand.org/donate