
Graphene Supercapacitors Ready For Electric Vehicle Energy Storage - nealabq
http://www.technologyreview.com/view/521651/graphene-supercapacitors-ready-for-electric-vehicle-energy-storage-say-korean-engineers/
======
zalzane
Note to reader: the supercaps in the article aren't being used for long-term
energy storage.

When a car brakes using magnets, a huge quantity of power is generated by the
magnets. In a typical setup, this power value is much higher than the maximum
rate at which the lithium batteries can absorb charge.

From what I gather, what this article actually means is that these supercaps
will be used as energy couplers between the regenerative brakes and the
lithium batteries. They aren't actually replacing the lithium battery.

~~~
redthrowaway
Presumably it'd work the other way, too? Supercaps that let you recover more
of the energy produced by regenerative braking should also give you short
bursts of acceleration, no? I imagine a system similar to the KERS system used
in F1:

[http://en.wikipedia.org/wiki/Kinetic_energy_recovery_system](http://en.wikipedia.org/wiki/Kinetic_energy_recovery_system)

------
venomsnake
Put it in my phone, tablet and laptop ... if I have something that I could
charge for 16 seconds I don't care how much it power source will last.

Also super-capacitors aren't that bad for medium term storage - they lose 10%
of the charge per day which is not much.

~~~
kbenson
I don't know much of the science, but I think if it can charge that quickly,
it can probably discharge pretty quickly as well. I imagine I wouldn't want to
be on the receiving end of that, so maybe there are drawbacks to putting it
into a device you hold in your hands?

------
alooPotato
So is the idea here that you would use these supercapacitors as the primary
energy store? Or is the case that you would use them to quickly capture the
energy from regenerative breaking and then use it to slowly charge traditional
batteries over time?

~~~
InclinedPlane
I think the idea is that you capture the energy from regenerative braking in
the super capacitors and then drain them almost immediately when acceleration
is called for (which means the batteries need to be used a lot less and thus
last a lot longer).

------
XorNot
I've been hoping for a supercapacitor laptop battery for some time. I'll
gladly take a 3 hour battery life if I can get a 30 second recharge.

~~~
sigterm
Not sure if I want to carry that kind of high power energy source in my bag,
or on my lap...
[http://www.youtube.com/watch?v=EoWMF3VkI6U](http://www.youtube.com/watch?v=EoWMF3VkI6U)

~~~
sgift
I don't see how this video shows anything which supports your .. fears?
Obviously, you shouldn't short-circuit capacitors. You shouldn't short-circuit
_any_ power source.

------
lsaferite
Sounds interesting but how exactly is 64Wh/kg "almost comparable" with
100-200Wh/kg?

Personally, I'm all for supercaps for regenerative braking right now and will
love to see a day when we can fully charge an EV in 30 seconds.

------
LAMike
How can something so small have more surface area than a basketball court?

~~~
PhasmaFelis
Imagine a sheet of paper the size of a football field but infinitesimally
thin. Now, fold it in half. Fold it in half again. Continue folding it in half
until it's the size of a postage stamp. You now have something with the
surface area of a football field that you can easily fit in your wallet.

~~~
DateK
Can the infinitesimally thin paper be folded more than 8 times?

~~~
sasoon
Mythbusters folded it 11 times,
[http://www.youtube.com/watch?v=kRAEBbotuIE](http://www.youtube.com/watch?v=kRAEBbotuIE)

------
zik
The big question is how long they can retain the charge. Supercapacitors
generally have a much higher self-discharge rate than batteries.

~~~
danmaz74
I think the first usage would be to recover energy from the brakes, energy
that you can use almost immediately afterwords. You would still use another
battery as the main storage.

