Graphene supercapacitors are 20x as powerful, can be made with a DVD burner
extremetech.com
extremetech.com
Fast recharge is also inconvenient. Just as you must have a set of batteries to swap, you must have the means and opportunity to fast recharge. Note that a fast recharger is probably at least as big as a set of batteries. And, I can swap batteries in places where I can't plug in the recharger.
Yes, fast recharge is less inconvenient than slow recharge.
If I'm ever around to recharge quickly I can just as well let it sit there for a while, at least the vast majority of times. Please note how convenient it is to charge from a USB-port, a micro usb cable is all that is needed to be able to charge pretty much anywhere (and they are cheap enough leave one at home/work/laptop/pocket. With a fast charger I'd have to bring it along and plug it in everywhere - not worth it. And I most definitely would like at least the same poor battery life that we have today, otherwise you wouldn't be able to last a day without a charge and that it just unacceptable regardless of how easy or fast it is to recharge.
(A real-world application would probably kick up the voltage and lower the current, but USB is always 5V)
Who said that you can only swap new/non-rechargable batteries?
> Swapping batteries is also significantly more effort than plugging in a microUSB or whatever.
Yes, but you can swap batteries where there's no power.
You're not willing to carry a spare set of batteries yet you insist that you're willing to carry a charger....
It's not fiddly like opening the case of a phone and swapping out the battery, but the big problem with this is having to leave it hooked up while it charges if you're still using your phone. With fast recharge, this would go away. Hook it up for a minute, charge the phone up, unhook it, put it away. Easy peasy.
For me, at least, this would be a huge win. YMMV
Edited to add: with fast recharging, you could also recharge the portable charger itself if you ever come in contact with an outlet. So let's say you have two really long flights with a short layover. Find an outlet for a minute on the layover, recharge the charger, and you now have your charger ready to go for the next flight. Win.
But we're used to being disappointed by articles about graphene... Anyone got a reason this isn't as good as it sounds?
I'm not an expert, but just working from the graph in the article, the best energy density they show for the new graphene capacitors is roughly 1/8th the best energy density for lithium-ion batteries. What's interesting is that capacitor has roughly 500x the power density of that battery. Or if you look at a battery tuned for power density (lower-right end of the red arc in the graph), there's a capacitor that can offer 200x or more power density with the same energy density.
More simply: for low-discharge-rate applications, lithium-ion still wins, though the new capacitors may narrow the gap a bit. For high-discharge-rate applications, these capacitors win by a mile. (Ignoring considerations not covered in the chart -- cost, durability, temperature sensitivity, safety, etc.)
Toy helicopters? EMP weapons?
Weight would be an interesting graph axis!
In most cases I think that this will not displace Li-ion but would instead augment the existing battery setup.
I mean, obviously not, but it's interesting to think about.
Would be great during a layover in a typical US airport where you might have to sit on the floor in a corner to use a power outlet. You could plug in for 10s to fill the cap, eat lunch while the cap charges the battery for an hour, plug in again for 10s before you fly out having something close to a full battery.
Also there are real safety issues with something that can be charged that fast, because it usually implies it can be discharged faster. A shorted Li ion battery may burn, but a low-resistance capacitor will cause an explosion. Capacitors are fun :-)
But until someone finds a way to package an actual component into something that looks like a supercap or a battery, no one will care.
Back when maxwell tech [1] was using them to start diesel electric locomotives I did the math to figure out how many I would need in my house foundation to 'carry me' over from day to night, and it was an additional $128,000 and probably 1000 sq ft of 'foundation' space to hold them.
Graphene, and other high surface area + high conductivity solutions seem like they will make this configuration more feasible in the future. It would be interesting to be 'off grid' but without the cost/hassle of maintaining a bunch of batteries.
http://www.extremetech.com/wp-content/uploads/2012/03/energy...
Edit: I'd like to personally thank everyone upvoting the previous paragraph. You are the wind beneath my wings.
And existing battery chemistries can already charge fast enough such that the limiting factor for electric car recharge times is the grid. My Nissan Leaf can charge most of the way in 25 minutes at a L3 charging station. But PG&E levies enormous fees for people who want to pull down that kind of power, so there isn't a single operable L3 station in the whole bay area.
The energy density of gas/petrol is fantastic. Recharge time is quick ("pour some in").
http://www.gizmodo.com.au/2011/12/a-gallon-of-petrol-can-pow...
http://www.mtimicrofuelcells.com/
Sure, we have limited supplies of hydrocarbons in the ground, but to me the key energy technology would be "synthesise hydrocarbons from water + CO2 + energy in". i.e. stop focusing on hydrocarbons as a source of energy and start thinking of them as a 'transport' of energy.
That would also mean we can move to clean, renewable power generation without retooling the globe's transport fleet.
http://web.mit.edu/newsoffice/2011/sun-free-photovoltaics-07...
The solid-state engine has much lower efficiency than a regular power engine would (a hypothetical 12%/realized 5% vs. a realized efficiency of about 30%), but it can be made much smaller - and even at a 5% conversion rate, the energy density just blows everything else out of the water. Aside from being energy dense, it's also much cheaper than high-end lithium-ion batteries; and unlike regular fuel-cells, the technology is just based on regular photovoltaics, and is relatively easy to manufacture.
What do we need to be able to hook up a nuclear power plant, a supply of clean water and a big air pump and starting sucking in H2O+CO2 and piping out CnH(2n+2) and pumping out O2?
Hot :-)
I believe this is called photosynthesis.
It would also be nice to be able to capture the energy output of other energy sources, e.g. nuclear in a nice, energy-dense liquid form.
http://www.aaas.org/news/releases/2012/0315sp_capacitor.shtm...
Yes, it is very informative/clarifying.
Here's my concern with regards to electric cars: There's a huge difference between failure modes of electric vs. gasoline powered vehicles in crash scenarios.
In a great deal of cases a crash with a gasoline-powered car results in no spills or fires. No problems. In a few cases a spill might result. Fires are only a factor when gasoline vapors are involved.
If a pure electric vehicle has a range equivalent to that of a gasoline-powered vehicle, say, 200 to 300 miles, this means that it is storing a tremendous amount of energy. Also, due to i-squared-c losses it is very likely that the system will be a high voltage system (hundreds of volts).
In the case of a bad accident this energy could be released violently. There might come a day when we hear of an entire family electrocuted to death in their car after a crash. I hope this never happens, but I have a feeling it could.
As I see it this is the PR problem with the technology: Huge amounts of energy that could do serious damage if something goes wrong. In contrast to that, a gas tank is a relatively harmless device.
Yes, there are safety measures that can and are being utilized, like fusible links between batteries and intelligent management systems. Still, it doesn't take much at, say, 500 volts, to cause a lot of damage quickly. As someone who has worked with and designed very high power DC motor controls and have tested many designs to destruction I have to say that this is an area that really needs to receive a tremendous amount of attention.
The last thing the industry needs is the media devoting weeks to cover how a family got fried in their electric car while the fire department was powerless to aid them until the batteries fully discharged (which could take a long time). That would be a truly horrific sight to behold and a potential industry-killing event. Close your eyes and imagine that for a moment. Then imagine trying to convince someone who saw that on TV to buy an electric car.
Super-capacitors could help in this regard in very meaningful ways. If we could get battery packs to be small enough that leaves a lot of room for creating a crash and intrusion protection barrier around the battery.
Today battery packs are very large and heavy. And, while I am sure that a lot of work has gone into safety, they could be made far safer if the batteries had higher energy capacities.
The other way super capacitors might be able to help could be as paradigm shift enablers. Picture the case of not needing a range of 300 miles. For most of us, 60 miles might be enough. If that battery pack is small enough gas stations could morph into battery pack swap stations. The fact that a super-capacitor has a useful life of tens of thousands of cycles means that there would be no concern of receiving someone's almost-dead battery. The cost of re-fueling would include some amount of money to deal with packs near or at their end of life. If you did need to go farther maybe cars could be designed with room for a second range-extension pack or some other means to connect a larger battery pack.
From a safety standpoint, I want to see the kinds of tests companies like Volvo and Mercedes are known for: Fling a car through the air and roll it multiple times. In other words, extreme stuff that is unlikely to happen in most accidents. After the tests the cars have to remain in a state that is safe enough for egress as well as for rescue personnel to approach, touch and render aid.
In other words, electric cars have to be better in terms of safety than gasoline powered vehicles.
But I agree that a death-by-car-electrocution scenario would be big news, and not a good thing for electric car makers.
We've all seen the laptop-going-nuclear videos when Li-Ion batteries short. This could be worse, given the high discharge potential mentioned in the article.
Only if it happens frequently. If it happens in one of ten thousand fatality accidents, you won't even be able to see it in the statistics.
People are used to gasoline. They are comfortable with it, if you will. Electricity is another matter. People fear electricity. They don't understand it. If electric cars are seen as roving high-tension wires that can electrocute you and your family in a crash that will be the end of the industry. People don't care about statistics but they react very readily to anything that triggers fundamental fears.
You know I thought most people know that gasoline burns and that they have to be really fucking careful with the stuff.
Same thing they also already know about electricity.
So, I am not sure that you could stop the electric car industry by worrying people that the energy store could kill them, as everybody who has been on the roads long enough has seen burned out cars from pile-ups at some point.
You only need ONE case of this accident covered on TV to get the industry into serious problems. Electric cars are new, thus interesting for media, and will capture attention (read: scare people).
And people really don't care about statistics, they do care about what they see in TV. Unfortunately, news services break our perception of reality. See: http://en.wikipedia.org/wiki/Availability_heuristic. That's why people freak about shooting in schools when the chance that their child gets run over by a car is much, much higher. Or, [insert random post-9/11 paranoia] vs. cancer rates. Or, what Chernobyl and Fukushima did to public perception of otherwise safe nuclear power.
I vividly remember my teenage stupid stunts with large capacitors charged at high voltage - those things can do a lot of damage when shorted. Also, a typical lead battery can do a number of nasty things, like release hydrogen, when mistreated; or throw a thick copper bar on a lead battery's contacts, and watch it melt down in seconds.
I'm sure you could install safeguards against the various failure modes, but again, you're still carrying a big chunk of lightning in your car.
Furthermore, keep in mind that both batteries and capacitors have a limited power rating. Power is the energy that can be spent or released per unit time. Thus a limited power rating means that the batteries/capacitors can only release a limited amount of energy for a given time. Thus they cannot release all the energy they have stored for driving 300 miles in a second. That is just not physically possible. Since the power rating is usually an engineering constraint, this generally means that the stored power for driving 300 miles can usually only be released around the time it takes to drive for 300 miles. Perhaps a little quicker. But the idea that all this energy will get released instantaneously frying everyone in the car is just impossible with current battery technology.
If you worry about instantaneous energy release you should worry about gas powered cars, because gasoline can release all of its energy instantaneously in a giant fireball. But even this is highly unlikely.
Fuses have nothing to do with not dying, fuses are not a life safety device. Your protected for the same reason your safe inside a car that gets hit with lightning, for electricity to pass through your body you have to be a path to ground more over you have to be a very good path to ground compared to other available paths, both of which are highly unlikely in the circumstance being discussed.
In terms of electrical energy discharge that would be determined by the voltage across your body and the resistance of your body given the contact points, environmental conditions and duration of contact. The ability of the battery to supply enough energy is really irrelevant, it takes a very small amount of current across your heart to send it into fibrillation. But, as just mentioned, you'd actually have to create a potential across your body first anyway.
> Since the power rating is usually an engineering constraint, this generally means that the stored power for driving 300 miles can usually only be released around the time it takes to drive for 300 miles. Perhaps a little quicker.
That is completely incorrect. I have no idea what constant your talking about but many/most/all batteries can discharge energy far faster than they would under standard operating conditions. You can even short them out and watch a nice explosion in many cases, which is far more likely to kill you than getting electrocuted in the example at hand.
The gasoline powered car contains much more energy. The average gasoline engine is about 20% energy efficient. Electric power systems are more like 80%.
> There might come a day when we hear of an entire family electrocuted to death in their car after a crash.
How do you expect the entire family to become a better path to ground than anything else? Especially considering the nature of the virtual ground in such a system?
>The last thing the industry needs is the media devoting weeks to cover how a family got fried in their electric car while the fire department was powerless to aid them until the batteries fully discharged (which could take a long time).
Not if they are so shorted they are "frying" something.
The real trick would be to build the system that could reliably de-power the relays in the case of an accident, but would also be reasonably trivial to reset in the case of false alarm, e.g. when an accident ends up being sub-critical. An end-user reset might also restrict the car to 'limp mode' until it's inspected by a qualified person.
Or your car has a 60km range battery built in and for longer trips you stick an extra capacity battery in the boot and plug it in. It's a lot easier than adding/removing a gas tank as needed.
One of the fantastic things about grapheme is that it is so easy to work with and abundant material.
This simple method of reduction means you could create a machine for making long sheets of grapheme just with an uniform focusing laser bar, this means mass scales and super cheap. Very exciting!!