Alternative to traditional batteries moves a step closer to reality after exciting progress in supercapacitor technology

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Lithium-ion batteries could be under threat after the development of polymer materials by the Universities of Surrey and Bristol, along with Superdielectrics Ltd, that could challenge the dominance of these traditional batteries.

Only one year ago, the partners announced scientific results for novel polymer materials that have dielectric properties 1,000 to 10,000 times greater than existing electrolytes (electrical conductors). These stunning scientific findings have now been converted into 'device' scale technical demonstrations.

Researchers from the universities achieved practical capacitance values of up to 4F/cm2 on smooth low-cost metal foil electrodes. Existing supercapacitors on the market typically reach 0.3F/cm2 depending upon complex extended surface electrodes.

More significantly, the researchers managed to achieve results of 11-20F/cm2 when the polymers were used with specially treated stainless-steel electrodes – the details of which are being kept private pending a patent application.

If these values of capacitance can be achieved in production, it could potentially see supercapacitors achieving energy densities of up to 180Wh/kg—greater than lithium ion batteries.

Supercapacitors store energy using electrodes and electrolytes and both charge and deliver energy quickly – conventional batteries perform the same task in a much slower, more sustained way. Supercapacitors have the ability to charge and discharge rapidly over very large numbers of cycles. However, because existing supercapacitors have poor energy density per kilogramme (currently around one twentieth of existing battery technology), they have been unable to compete with conventional battery energy storage. Even with this restriction, supercapacitor buses are already being used in China, but the current technology means that they need to stop to be recharged frequently (i.e. at almost every bus-stop).

The team of scientists have been able to test the new materials in two ways:

  • By using small single layer cells charged to 1.5 volts for two to five minutes and then run demonstration devices, including a small fan.
  • By using a three-cell series stack that is able to be rapidly charged to five volts and operate an LED.

The University of Bristol is going much further by producing a complex series-parallel cell structure in which both the total capacitance and operating voltage can be separately controlled.

Based on these impressive results, Superdielectrics Ltd, the company behind this technology, is now looking to build a research and low volume production centre. If successful in production, the material could not only be used as a battery for future mobile devices, but could also be used in refuelling stations for electric cars.

Dr. Brendan Howlin, Senior Lecturer in Computational Chemistry at the University of Surrey, said: "These results are extremely exciting and it is hard to believe that we have come so far in such a short time. We could be at the start of a new chapter in the technology of low cost that could shape the future of industry and society for many years to come."

Dr. Donald Highgate, Director of Research for Superdielectrics Ltd and alumnus of the University of Surrey, said: "These exciting results are of particular satisfaction to me because they build upon my work in hydrophilic polymers that has been a major part of my professional life; beginning in the later 1970s with extended wear soft contact lenses, and leading in the period 1990 to 2009, to fuel cells and electrolysers of exceptional efficiency.

"The present work, if it can be translated into production, promises to make rapid charging possible for electric vehicles, as well as offering a much-needed low cost method of storing the transient output from . Wind, wave and solar energy is available but it is intermittent and, without storage, cannot be relied upon to meet our energy needs. This new work would transform the energy system which underpins our entire way of life – it is the necessary development before we and our children can have a genuinely sustainable, environmentally safe energy supply."

Dr. Ian Hamerton, Reader in Polymers and Composite Materials from the Department of Aerospace Engineering at the University of Bristol, commented: "Following the unveiling of the preliminary results at the first press conference just 14 months ago, the team has worked hard to increase the storage capability of these innovative materials still further. Our foremost challenge is now to translate these scientific findings into robust engineered devices and unlock their revolutionary potential."


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Feb 26, 2018
up to 180whr/kg—greater than lithium ion batteries.


False. Lithium-ion batteries reach 250 Wh/kg

And a capacitor with an energy density of 180 Wh/kg is a bomb, since the energy is stored electrostatically rather than chemically. The charges can rapidly recombine when the insulator fails.

Here's a 1 Farad 12 Volt capacitor exploding:
https://www.youtu...R58pLmlQ
That's around 144 Joules, or 144 Watt-seconds, which is 0.04 Watt-hours as compared to the 180 Wh

144 Joules is approximately equal in energy to a small caliber pistol shot. Now imagine the release of energy when a capacitor with 5,000 times the energy fails catastrophically. This is why storing very large amounts of energy in capacitors is a very bad idea. Just as bad as trying to design an engine that runs on straight up nitroglyserin.

Feb 26, 2018
@Eikka doesn't like supercapacitors. They upset its rightwingnut anti-renewable ideology.

There are engineering solutions to these problems, @Eikka.

After reviewing the recent article on physorg about carbon nanotube/graphene electrodes, I'd say supercapacitors are starting to become more and more practical.

Feb 26, 2018
#E, don't forget those incendiary mobile phones' Li-Ion batteries. And, hey, if you've ever seen a 'classic' lead-acid battery short circuit, you'd run a mile...

Feb 26, 2018
@Eikka doesn't like supercapacitors. They upset its rightwingnut anti-renewable ideology.

There are engineering solutions to these problems, @Eikka.


Bullshit ad-hominems. A capacitor is a capacitor - a modern capacitor is an electrostatic device where two opposite charges are separated by an atomically thin oxide barrier that prevents them from recombining and releasing their energy. Once the barrier is lost, the charges will recombine, because they physically attract each other. A capacitor as an energy storage device is like a wound up spring - the stored energy is in the tension between the charges, literally, as the closer they get to each other the stronger they pull.

There isn't an engineering solution against that without completely changing the principle of operation of the whole device - making it not a capacitor.

Feb 26, 2018
Alternatively, you can section the capacitor off into small cells which each make only a tiny bang when they fail, but then you'll compromize the energy density by having so much packaging material in between thousands and thousands of cells, and it will always be more expensive to manufacture it that way.

Feb 26, 2018
@Eikka, you're *always* against new storage technology.

Now, why is that? I mean, just askin'.

So much for your claims of ad hominem. I'm just noting what you say. If you don't like it you probably shouldn't say it.

Feb 26, 2018
@Eikka, you're *always* against new storage technology.


Nope. I'm against bullshit hype. It's not my fault that most of the reporting on new tech tries to spin it as far greater than it actually is.

High energy density capacitors are great in power electronics and some small devices, but they do not replace traditional batteries because of what a capacitor is and how it functions. It would just be insane.

#E, don't forget those incendiary mobile phones' Li-Ion batteries. And, hey, if you've ever seen a 'classic' lead-acid battery short circuit, you'd run a mile...


Batteries can get very dramatic as well, but at least there's a limit to their reaction rates. They don't just go BANG, except the lead acid battery which can easily develop hydrogen gas which does go bang and people have been killed because of it.

Feb 26, 2018
Sorry, @Eikka, I've seen your posts on other subjects too, and your ideology sticks out all over the place.

Why don't you stick to rightwingnut sites where you won't get pwnt?

Feb 26, 2018
So much for your claims of ad hominem. I'm just noting what you say.


You're just projecting your own boogeymen on me, and then complaining that it doesn't look pretty.

And ad-hominem means attacking the person instead of the argument, which you do. I told you why capacitors are a bad idea, and you just brush that off by claiming that I'm a "rightwingnut" - which is exactly the kind of dishonest bullshit that people do when they don't actually have anything to say, and they just want to shoot the messenger.


Feb 26, 2018
Speaking of naïve academical twaddlers separated from reality, how you doing with those black holes and coordinate systems, @macurinetherapy?

Feb 26, 2018
This supercapacitor is double layer one and it's charged to few volts only. So that it didn't explode because of shortcut, but because overchanging by external battery.


Same difference. Overcharging increases the voltage to the point where the insulating barrier is lost, which causes a rapid internal discharge, which quickly produces tons of heat and blows out the can.

If you apply just a few volts to the capacitor, it won't do anything. It just charges up to those few volts. They put two car batteries in series to push 24 Volts into an audio amp buffer capacitor which is typically rated for 12-18 Volts max, which makes it short out on the inside.

Feb 26, 2018
So much for your claims of ad hominem. I'm just noting what you say.


You're just projecting your own boogeymen on me, and then complaining that it doesn't look pretty.
Sorry, this has been noted by other posters. Do you really want me to embarrass you by pulling all this up by looking over your posts here and linking them? Because if you make it worth my while, I'll be happy to.

Get over your ideology and pay attention to the science, this being, after all, a science site.

And ad-hominem means attacking the person instead of the argument,
Correct, and you keep making arguments against renewables and storage technologies. Pretty obvious, man.

Feb 26, 2018
Speaking of naïve academical twaddlers separated from reality, how you doing with those black holes and coordinate systems
This is brilliant example of academism separated from real life - thank you for real life demo...:-) In addition I can see ad hominem and attempt for subject change rhetorical fallacy.
I would call BS on that. You're making claims you can't substantiate about black holes and coordinate systems. I see no reason to believe any of your other claims are any better, particularly when you can't respond, seek to attack on another thread instead of addressing your lies on the thread where you told them, and make ad hominem attacks like "naïve academical twaddlers separated from reality."

Bring it, troll @macurinetherapy.

Feb 26, 2018
@Eikka, your safety arguments are all based on the one giant capacitor, and you just got pwnt because the supercap explosion you linked was because it was overcharged, not because of physical damage as you were claiming.

Looks like you lied. And got caught. As usual for anything you say to do with renewables or storage tech.

Feb 26, 2018
Sorry, @Eikka, I've seen your posts on other subjects too, and your ideology sticks out all over the place.

Why don't you stick to rightwingnut sites where you won't get pwnt?


I'm glad we have you as both our judge and jury, and the lawmaker.

Again, you're projecting your own bogeymen on me, because you disagree with me. I must be an evil right-wing nut, because only evil right-wing nuts would say things you don't agree with, therefore all the things I say must be wrong, even if I didn't actually say it, because it's implied.

See how it works with you? You think that because I oppose typical naive left-wing policies for their obvious flaws means that I support the right wing, or that I hate renewable energy because that fits the stereotype you're tilting against.

I don't hate renewable energy. I hate all the bullshit and political abuse and corruption that's going on around it.

Feb 26, 2018
So "naïve left-wing policies" isn't ad hominem? And rightwingnut ad hom at that?

Just askin'.

Stop lying about your attitude on renewables, @Eikka. It's as transparent as a 3-year-old caught with hand in cookie jar.

Feb 26, 2018
@Eikka, your safety arguments are all based on the one giant capacitor, and you just got pwnt because the supercap explosion you linked was because it was overcharged, not because of physical damage as you were claiming.


Same difference. Overcharging causes physical damage - it's just one of the failure mechanisms.

Looks like you lied. And got caught. As usual for anything you say to do with renewables or storage tech.


Oh, we're going down this road again.

Sorry, this has been noted by other posters. Do you really want me to embarrass you by pulling all this up by looking over your posts here and linking them? Because if you make it worth my while, I'll be happy to.


Argument ad populum. Please do pull out your sockpuppets and spam the board. Waste your time - my arguments stand on their own merit.

and you keep making arguments against renewables and storage tech


That's not how it works, and I don't in general. You lie.

Feb 26, 2018
@Eikka, your safety arguments are all based on the one giant capacitor, and you just got pwnt because the supercap explosion you linked was because it was overcharged, not because of physical damage as you were claiming.
Same difference.
No, it's not the same at all, and you can't possibly not know that. The mechanisms are completely different. You're talking about supercaps exploding in cars as a result of collisions, which will not cause all the cells in a segregated supercap array to breach all at once. You're lying again, @Eikka.

I won't bother with the rest since you started with a lie. Try again. Good luck. I only give trolls one lie.

Feb 26, 2018
So "naïve left-wing policies" isn't ad hominem?


Yes. Ad-hominem is directed against a person. "Left wing policy" isn't a person. "Renewable energy" isn't a person, etc.

You're just misusing the term now.

Stop lying about your attitude on renewables, @Eikka. It's as transparent as a 3-year-old caught with hand in cookie jar.


As I deny, you call me a liar. Kafka trial - you've set yourself up as the winner in any case. There is no convincing you because you are projecting.

Feb 26, 2018
So "naïve left-wing policies" isn't ad hominem?


Yes. Ad-hominem is directed against a person. "Left wing policy" isn't a person. "Renewable energy" isn't a person, etc.

You're just misusing the term now.
Actually, ad hominem can be against a group as well as a person.

From Wikipedia:
Ad hominem, short for argumentum ad hominem, is a fallacious argumentative strategy whereby an argument is rebutted by attacking the character, motive, or other attribute of the person making the argument, ***or persons associated with the argument***...


And you're lying again, @Eikka. Remember, only one lie.

Feb 26, 2018
@Eikka's arguments regarding future highvoltage supercapacitors are perfectly on place - but their arguing by double-layer capacitor tortured by automobile battery is just plain silly. Every passive component could explode at the case of its excessive loading by external energy source.


Not every component will outright explode by being subject to an overload. The point was about the rapidness of the reaction, not the fact that the device got destroyed.

No, it's not the same at all, and you can't possibly not know that. The mechanisms are completely different.


Yes it is the same. The insulator gets broken and the capacitor is shorted out internally. Same difference

You're talking about supercaps exploding in cars as a result of collisions


Chech the thread - I didn't. I did not specify any particular or mechanism of failure. You're just projecting again, which is the main probem with you. You're arguing against yourself.

Feb 26, 2018
Actually, ad hominem can be against a group as well as a person.


"Left wing policy" isn't a group either. I argue against the policies, not the people making them. Particularily, the naive policies. I have nothing against left wing policies in general, just like I don't have anything against renewable energy or storage technologies in general and in principle, because I don't argue based on labels like you do.

There's no point in continuing this discussion because you're incorrigible.

Feb 26, 2018
@Eikka, so this is the only thread you've ever posted on here? And you've never claimed that supercaps are dangerous in a collision on this site?

Meanwhile, "left wing" is a group.

You're lying again. In every post you make.

Feb 26, 2018
@Eikka, so this is the only thread you've ever posted on here? And you've never claimed that supercaps are dangerous in a collision on this site?


Yes I have, and I stand by that assertion. Supercapacitors can be dangerous in a collision for reasons already mentioned.

Meanwhile, "left wing" is a group.


True, but irrelevant. I said I argue against naive left wing policies, not "left wingers". You're simply twisting my statement.

You're lying again. In every post you make.

You're just ignoring every single point I'm making. You're incorrigible.

Feb 26, 2018
@Eikka, so this is the only thread you've ever posted on here? And you've never claimed that supercaps are dangerous in a collision on this site?


Yes I have, and I stand by that assertion. Supercapacitors can be dangerous in a collision for reasons already mentioned.
See? I figured you'd back down. Sorry, another lie. And caught again. My assertion stands: physical damage is not equivalent to electrical damage.

Meanwhile, "left wing" is a group.
True, but irrelevant. I said I argue against naive left wing policies, not "left wingers". You're simply twisting my statement.
And now you're lying yet again; we're arguing about the definition of ad hominem, and it's obvious that by including "left wing" in the statement you've made an ad hom attack. And if you left "left wing" out you'd be making an ad hom against me by calling me naïve.

Just stop lying, @Eikka. It's obvious when you do it.

Feb 26, 2018
Meanwhile, I'm countering every post you make; I just refuse to deal with a farrago of lies. Telling multiple lies in one post is a classical Gish Gallop.

Feb 26, 2018
See? I figured you'd back down. Sorry, another lie.


Apology accepted. I don't see where I backed down from anything.

And caught again. My assertion stands: physical damage is not equivalent to electrical damage.


False. "Electrical damage" IS physical damage, to the insulating barrier inside a capactor, which causes it to physically fail to keep the charges separate. You're just confused, or trying to confuse the matter by switching terms.

And now you're lying yet again; we're arguing about the definition of ad hominem, and it's obvious that by including "left wing" in the statement you've made an ad hom attack.


That's not how it works. When I say "naive left wing policies", that phrase directs to "naive policies", not "left wing", which was included in this context only because you asserted that my opinions make me a "rightwingnut".

You know that perfectly well. You're just trying to confuse by going off on irrelevant tangents

Feb 26, 2018
And if you left "left wing" out you'd be making an ad hom against me by calling me naïve.


What I said was:

"You think that because I oppose typical naive left-wing policies for their obvious flaws means that I support the right wing"

That wouldn't be calling YOU naive even if "left wing" was left out. You're twisting my words completely!

Feb 26, 2018
See? I figured you'd back down. Sorry, another lie.
Apology accepted. I don't see where I backed down from anything.
Sure you did. You claimed you'd never said that collision damage could make all the supercaps in an electric car fail catastrophically and blow the car up. As far as apologizing I wasn't; I was only telling you I regretted you'd made a fool of yourself.

And caught again. My assertion stands: physical damage is not equivalent to electrical damage.
False. "Electrical damage" IS physical damage, to the insulating barrier inside a capactor, which causes it to physically fail to keep the charges separate. You're just confused, or trying to confuse the matter by switching terms.
No, I'm pointing out that you're claiming that making all the bulkheads in a cap fail at the same time is the same as making some of them fail.

You're lying again, @Eikka. As I said, you lie in every post.

Feb 26, 2018
I would argue that carrying around a 15 gallon gas tank is at least as dangerous as carrying around supercaps. And the supercaps are as susceptible to engineering solutions as the gas tank.

Feb 26, 2018
Oh and BTW @Eikka, the electronics and physics of supercaps, and ways of making renewables work better, aren't "naïve left-wing policies."

Just sayin'.

Feb 26, 2018
Sure you did. You claimed you'd never said that collision damage could make all the supercaps in an electric car fail catastrophically and blow the car up


No I haven't. I simply said that I am not talking about any particular failure mode or mechanism, but about capacitor failure in general. You said: "You're talking about supercaps exploding in cars as a result of collisions ", which I did not mention here in this thread.

It's incredible that you can't even scroll up to check up what the discussion is about before you go off the rails accusing other people of lying.

No, I'm pointing out that you're claiming that making all the bulkheads in a cap fail at the same time is the same as making some of them fail.


Again, not something I said.

And, you're making the assertion that the capacitor is constructed in a specific way, and I already addressed that point: if the capacitor is made of multiple small cells, the energy density goes down due to packaging.

Feb 26, 2018
I would argue that carrying around a 15 gallon gas tank is at least as dangerous as carrying around supercaps. And the supercaps are as susceptible to engineering solutions as the gas tank.


You may, and you'd be wrong: gasoline isn't in itself capable of explosion, and insulator failure is an inherent failure mode to capacitors which can't be engineered away. Whether by electrical overload or by poking a stick through the capacitor, when the insulator fails, if the capacitor has very high energy density, it goes BANG.

You can mitigate the issue by isolating the capacitor into smaller sections, but the necessary packaging would increase mass and therefore reduce energy density. Which was already said.

Oh and BTW @Eikka, the electronics and physics of supercaps, and ways of making renewables work better, aren't "naïve left-wing policies."

Just sayin'.


Neither did I say so. You're just mixing up different topics there.

Feb 26, 2018
The whole point is, that a capacitor is capable of discharge within itself upon failure, explosively.

With such devices, even if you have separating barriers or "bulkheads", as the net energy density of the system is increased - you stuff more energy in a tighter package - these barriers can no longer hold the explosion energy from spreading from capacitor to capacitor, and the whole thing blows up anyways.

It's like, if you have sticks of dynamite - it doesn't matter that you wrap them up individually in paper before you pile them in a box. Even if you dice them up small as sugar cubes - it's still a box full of dynamite. To prevent the potential of a big explosion, you have to add ridiculous amounts of padding between each piece, so that when one goes off the others don't. But then your box gets a whole lot bigger and heavier.

Which is why it's a good idea to store energy in something more inert, rather than in capacitors, or dynamite.

Feb 26, 2018
no double layer capacitor can explode because of short. They have high internal resistance and no insulating barrier in fact. I'm working with them on daily basis and they're completely safe in this regard.


Double layer capacitors do have insulating barriers

https://en.wikipe...science)

There's an electrochemical effect happening at the surface of the electrodes that turns the very surface layer into an insulator, which is why these capacitors have high capacitance: the insulating layer is atomically thin. These capacitors have high ESR because of the electrochemical nature of their operation, but once charged up full they too have the potential to release energy suddenly and explosively.

Above a certain threshold voltage the chemical reaction reverses and the barrier is lost. The capacitor starts to leak and heat up, and the more it heats up the faster it leaks, leading to thermal runaway. Having enough energy, it goes bang.

Feb 26, 2018
Y'all can argue about it all you want but I would like to have a good sized one that I could charge slowly with my electric assist trike's batteries as I go somewhere. It could supply the heavy amps the motors draw when taking off from a stoplight etc... It would probably give me more range that way. Maybe not a lot but every little bit helps and the 60+ amps the two small motors can pull at start for the first few seconds when I need to hurry across a road is a little hard on 32Ah batteries.

Feb 27, 2018
Atoms are indestructible
A super capacitor of 1.2volts with one way voltage regulators so adding them in series does not increase the voltage of each capacitor, where each capacitor has built in isolating switches making failed or faulty capacitors redundant, the electron in the atom has an energy density infinitely far greater than anyone is envisaging here, electrons do not vaporise when in motion with billions of their colleagues when combining force's. The material the capacitor is constructed of, is of the same atoms and it takes a nuclear explosion to break these atoms apart.

Feb 27, 2018
If one wants mobility one has to carry around a source of energy (unless we start to lay down cables in every street or the like). A concentrated source of energy can be released uncontrollably. This is no different from hydrogen to gasoline to batteries to supercaps (well, actually it's a lot better for batteries and supercaps because of the higher efficiency of electric drives you only need to carry around roughly 1/3 of the total energy content compared to a gasoline car)

But this isn't news and has been shown to be manageable for well over a century. So what's the fuss about? Neither gasoline cars nor electric ones are exploding at an alarming rate.

If you go by miles driven or percentage of vehicles on the road electric cars have less fires (and *much* less injuries/fatalities due to fires) than gasoline cars. And there are certainly enough of them on the road by now to have some confidence in the statistics.

Feb 27, 2018
The difference is, if this release can be explosive or not.

The difference, to me, would be whether people get injured or not. As the NHTSA study points out
https://www.googl...6sKUHjtB

Regarding the risk of electrochemical failure, the report concludes that the propensity and severity of fires and explosions from the accidental ignition of flammable electrolytic solvents used in Li-ion battery systems are anticipated to be somewhat comparable to or perhaps slightly less than those for gasoline or diesel vehicular fuels. The overall consequences for Li-ion batteries are expected to be less because of the much smaller amounts of flammable solvent released and burning in a catastrophic failure situation.



Feb 27, 2018
Just because the supercaps will be very new, this experience will be missing. The present situation is, the batteries got banned in planes for good reason


Well...ask yourself this: Would you have even thought of allowing gasoline powered smartphones/laptops on flights? No? Then you've just given yourself the answer which one you YOURSELF would consider safer

Feb 27, 2018
fires and explosions from the accidental ignition of flammable electrolytic solvents used in Li-ion battery systems are anticipated to be somewhat comparable to or perhaps slightly less than those for gasoline or diesel vehicular fuels.

The question then is, how would those fires or explosions compare to a comparable capacitor that caught fire or exploded?

Feb 27, 2018
The question then is, how would those fires or explosions compare to a comparable capacitor that caught fire or exploded?

It always depends on the energy content. I checked around a bit and my "1/3" number was a bit high. It seems the energy content in batteries in an electric car is more on the order of 1/10 of the energy content of gasoline in an ICE car. If capacitors replace batteries the energy content would be similar (or even lower, since recharging capacitors is not nearly as much of an issue as recharging batteries - so people might accept lower energy content without range anxiety).
If you look at the 200k fires for ICE cars per year in the US alone and the handful of fires for EVs worldwide then the fear of batteries starts to become a bit ludicrous (particularly since there hasn't been a single death due to fire in an EV - but plenty of those in ICE cars).
At over 100million miles per fire EVs beat out ICE cars by a factor of 5:1 in terms of safety.

Feb 27, 2018
ps #24V, thanks for making such a relevant comment ! As a 'peak assist' tech, super-capacitors would certainly off-load some of the current requirements. They would surely be useful for other 'hybrid' mixes.

Feb 27, 2018
Capacitors are the answer
High capacity capacitors have all the advantages, fast charging, fast dishing charging, light weight and unlimited charging without losing capacity after 6months, so these constructed properly will last the lifetime of the car, now all we need is a means of charging them up which does not involve filling the air with the fumes of burning fossil fuels as that is defeating the purpose of the exercise, as fuel to car is 25% where as fuel to electricity is 10% then a further reduction from battery to electric car motor making electric cars less green than petrol cars.

Mar 01, 2018
[...]an electric car is more on the order of 1/10 of the energy content of gasoline in an ICE car. If capacitors replace batteries the energy content would be similar (or even lower[...].

So let us consider a hypothetical capacitor with 1/12 energy content of gasoline, and a full charge. It fails due to the vehicle crashing, and next due to charging overload.

What are we seeing here? Is there only a low chance of explosion? Could it just catch fire? How big of an explosion could there be?

EVs beat out ICE cars by a factor of 5:1 in terms of safety.

Lithium-ion EV's, sure. How would Capacitor EV's compare to either?

Mar 01, 2018
Lithium-ion EV's, sure. How would Capacitor EV's compare to either?

Since these kinds of caps have nothing that can catch fire they would be even safer.

An issue could be risk of electrocution. That is higher with caps than with batteries (since the voltage of an individual cap is higher)...But since this can be easily mitigated by very simple (read: robust) crash detection systems I don't see this as much of a problem. To date I have not heard of any injuries/deaths due to "EV-electrocution after a crash".

Mar 01, 2018
An issue could be risk of electrocution.

So at an energy density of 180 Wh/kg, exploding wouldn't be a risk for these supercaps? Cool. That's what I was after. As a layman I have no idea how big/small a bang that would be.

rdp
Mar 09, 2018
I'm not much bothered by the fact that supercaps don't hold charge as long as chemical batteries.

In the first applications, supercaps will sit between the load and chemical batteries, delivering (and absorbing) large currents and extending the life of the batteries. As their energy densities increase, you'll have a system largely powered by supercaps with one modest chemical battery whose job is to to keep the supercaps charged up.

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