
Supercapacitors Batteries charges in seconds without degrading - Ideabile
http://today.ucf.edu/phone-charges-seconds-ucf-scientists-bring-closer-reality/
======
gus_massa
The size of the battery varies from phone to phone, but let's choose 3000mAh
as a typical value so the battery is enough for a full day.

If you want to charge it in "seconds", let's use 60 seconds as an upper bound.

So if the charger has a 100% efficiency, then it has to provide 3000mAh/60sec
= 3000mAh * 3600 sec/h / 60sec = 180000mA = 18A.

An USB can provide between 0.1A and 0.9A. For comparison, a typical plug in a
home can provide 10A. So to charge the phone you will need some big connector,
not a tiny microUSB like connector.

But it's worse. From the article:

> _" If they were to replace the batteries with these supercapacitors, you
> could charge your mobile phone in a few seconds and you wouldn't need to
> charge it again for over a week," said Nitin Choudhary, a postdoctoral
> associate who conducted much of the research published recently in the
> academic journal ACS Nano._

To recharge the phone once a week, I guess you will need a 20000mAH battery,
and a few seconds is something like 5, so the connector must survive to 1000A,
that is a ridiculous current.

~~~
Yetanfou

       a typical plug in a home can provide 10A.
       So to charge the phone you will need some big connector,
       not a tiny microUSB like connector.
    

Current capacity for conductors depends on conductor length as well as
conductor size. Short runs of a given size have a higher current capacity than
longer lengths due to the larger losses in larger lengths. Also, current
capacity depends on the length of time the current has to be carried: a given
length of a given conductor size will carry a larger current for a short
amount of time compared to the carrying capacity for a longer duration. While
a micro-USB connector will not suffice, the needed connector would not be that
much bigger: a 3.5mm jack would suffice to carry 18A for a few seconds given a
good socket. It would not be hard to design a plug/socket combination with a
high-enough capacity which would fit in a phone.

    
    
       To recharge the phone once a week,
       I guess you will need a 20000mAH battery
    

I recharge my phone (a Motorola Defy+) once a week. It has a ~1500 mAh
battery, the thing is 5 years old. I don't think you'd need a 20.000 mAh
battery to be able to keep your phone running for a week unless you plan to
use it as a hand warmer.

~~~
striking
How I wish there were a 4G phone that could do what you describe. My OnePlus
One has double that battery capacity (3100mAh) but I can really only make it
last two days on that charge at maximum. Typically it needs to be recharged
every day, or my usage habits need to change.

So 20000mAh accurately describes my average weekly cellphone power
consumption... and if I changed my habits a bit, I'd still expect to require
10000mAh.

Please, if you know of a 4G phone that can last for more than two days, no
matter how "dumb" it is (it could even be a flip phone, just as long as it can
tether) I'd love to know about it.

~~~
semi-extrinsic
FWIW, I have a Samsung A6 at work that I almost never use. It lasts 5-7 days
on one charge; but this only works when display and network are off 99.5% of
the time.

------
daveguy
Apparently they are on par with energy density and power density. They are way
ahead on cycle stability (30k charges). So that pretty much leaves two things:

1\. Charge stability. Does it leak like a sieve even without a load after
being charged?

2\. Manufacturability. I expect this is the big problem. It's a chemical
engineering problem to scale up a "nano" process. The article says it's not
ready, but doesn't say what the biggest challenge is going forward.

Anyone know this particular supercapacity tech? Or supercaps in general?

~~~
cperciva
A leaky capacitor could still be useful in combination with a battery - you
can dump power into the capacitor for a super-fast "charge", then slowly move
the energy into the battery. You don't get the capacitor's cycle stability,
but at least you get the charging speed.

~~~
adrianN
That would approx. double the size of your power storage, no?

~~~
cperciva
Maybe. Depends on the power density of supercapacitors, and also on whether
you can increase the power density of the battery when you're not worried
about making sure you can charge it as far as possible.

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gravypod
Coincidentally they also like to discharge in seconds!

~~~
daveguy
Is that true? All supercaps? This tech in particular?

~~~
nerfhammer
All supercaps. Shorting a charged supercap is vastly more deleterious than
shorting a battery or even a dc power supply.

~~~
finnh
Deleterious or dangerous? (ie, does it hurt the supercap, or the thing
shorting the supercap)?

"When first I appear, I seem deleterious / But when explained, I'm nothing
serious"

~~~
nerfhammer
Dangerous. Hurts the thing shorting the supercap and anything in close
proximity to that thing

~~~
jhou2
wow, it sounds like it would make Samsung's Note 7 battery problems seem
elementary. Who would want to carry a device like that in their back pocket or
hand it to kids to play with? Would a good drop on hard pavement or sheet
metal cause this thing to go off?

~~~
nerfhammer
It's not particularly easier to physically rupture than a normal battery. You
would have to smash it hard enough to break apart the device.

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kylehotchkiss
The scary part is that touching the two connectors of a supercapacitor is an
instant discharge. Which might prove pretty dangerous.

~~~
jrockway
They have some equivalent series resistance and internal resistance, but yeah,
try touching the two conductors of a Li ion cell together. Batteries and bombs
are basically the same thing -- store energy and release it very quickly.

~~~
dump121
Acually, for safety, do NOT try to short the battery. Just youtube it.

~~~
jrockway
Hah, yes, good disclaimer. It can be quite explosive under the right
conditions.

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seesomesense
The original article is High-Performance One-Body Core/Shell Nanowire
Supercapacitor Enabled by Conformal Growth of Capacitive 2D WS2 Layers DOI:
10.1021/acsnano.6b06111

and is available at the usual places.

------
sandworm101
>>> Anyone with a smartphone knows the problem: After 18 months or so, it
holds a charge for less and less time as the battery begins to degrade.

Really? That's still a thing? These aren't nicads. I've found that my phone
doesn't report full charge as often, but it still lasts for a similar amount
of time. My 5+yo netbook's battery is still reporting 80% of its design
capacity.

Imho, such apparently dramatic falls in capacity often have more to do with
running apps rather than physical degradation of the battery. Talk to me after
a reset to factory settings.

~~~
ant6n
My three-year-old MBP lasts about an hour. I think it lasted like 6-8 hours at
first.

~~~
kamilner
If it's under warranty, that's worth taking in. When I got my MBP repaired
under warranty they also noticed my battery was doing worse than it should for
the number of cycles and replaced it no questions without me having to ask. I
believe rated is 80% health after 1000 cycles, and mine was somewhere around
75% after 8 or 900---you can check the these values in system information, I
believe.

~~~
ant6n
Warranty was only for a year. I had it repaired at some point for some
heatsink issue, and they offered they could swap out the battery while at it
(i.e. no extra labor). But it would've cost me 300$ CAD just for the battery,
which seemed expensive at the time. Now I regret not paying for that..

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Tepix
Sorry for being cynical but I'll get excited only once I can actually buy this
latest battery breakthrough, not when it is still X years away.

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AndrewDucker
I thought that capacitors also discharged incredibly quickly. Can a capacitor
be used like a battery?

~~~
dragontamer
Most capacitors are measured in "micro"Farads.

Supercapacitors are measured in Farads, and the capacitors mentioned in this
article are likely reaching kilo-Farads.

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mrfusion
If this is true it would be revolutionary right?

~~~
hossbeast
True of the handful of battery breakthroughs that you hear about on a weekly
basis

