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Author: Subject: Help with a giga-battery (Electrochemistry)
Tungsten.Chromium
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[*] posted on 8-6-2015 at 20:25
Help with a giga-battery (Electrochemistry)


Hey everyone, a friend of mine is working making a giant battery for his home and asked me to assist him in finding a solution for the battery.

Now apart from a few videos on khanacademy a while back, I have absolutely no experience in the matter, and really don't know where to start.

For all those interested, we're looking for something that will have an output of .5-1.5 volts and something in the giga-amp range. (not a typo). Not really concerned with efficiency, but more on the cost aspect and that it needs to be stable at STP.

Hope I'm not asking for too much of a spoon-feed answer here and will really start digging into UTFSE tomorrow. Any feedback is supported! Thanks!

[Edited on 9-6-2015 by Tungsten.Chromium]




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[*] posted on 8-6-2015 at 21:21


Let's see. 1 volt. 1000 000 000 amps. That's going to be a gigawatt output. We are talking the same power output as a decent sized nuclear power plant here. Nothing you can make in your back yard will be able to sustain that output for more than the tiniest fraction of a second.
It sounds to me like you want a capacitor more than a battery. But I am confused about what possible application would require such a huge current.
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gatosgr
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[*] posted on 8-6-2015 at 22:08


you need a supercapacitor array
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aga
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[*] posted on 9-6-2015 at 02:15


Get one of these off ebay :

http://www.newscientist.com/article/mg21028174.900-universes...




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[*] posted on 9-6-2015 at 02:51


Here ya go:

http://www.sciencemadness.org/talk/viewthread.php?tid=51860
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Tungsten.Chromium
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[*] posted on 9-6-2015 at 06:17


Thanks for all the quick replies! I'm not sure what the intended purpose is exactly (maybe a flux capacitor?), but I'm going to try and meet with my friend and discuss what exactly it will be used for either today or in the next few days.

hyfalcon, thank you for the link to that thread, it is very helpful!




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Praxichys
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[*] posted on 9-6-2015 at 08:04


You will never achieve a Gigaampere. I'm not sure you understand how much a billion really is.

A billion amps is a stupid amount of current. If you were to make a battery capable of supplying that kind of current, your conductors would have to be extremely thick. In a typical electromagnetic can crushing experiment, 14AWG copper wire EXPLODES when subjected to a peak load of 25kA. You are proposing a current 40,000 times higher than that! Doing the math, you would be able to make a round copper bar 6.5 inches in diameter and 6 feet long, explode from overcurrent. (Look up wire cross section and resistance per length) Consider that the copper bar would weigh 771 pounds and at $3 per pound for scrap copper, would cost $2300. Designing conductors to carry that safely would be incredibly expensive, not to mention HUGE.

You would also need switchgear that does not exist, not to mention the far reaching effects of the colossal magnetic field that would be generated while the current was flowing.

Quote: Originally posted by gatosgr  
you need a supercapacitor array
This would not work. Their internal resistance is too high for the voltage provided. Max current of a discharging capacitor is determined only by the charging voltage and the resistance of the discharge path. Any increase in capacitance merely increases the duration of discharge.

Limiting the bank to 1V would require a discharge path of .000000001 ohms resistance to achieve 1 billion amps. This is very unrealistic, and impossible with the internal resistance of the capacitors alone.

Even with a charge voltage of 5kV, the numbers are not much better: .000005 ohms, the equivalent of a microscopically short length of 14 AWG copper wire, would be required to hit one billion amperes. It's impossible unless you invent some sort of superconducting supercapacitor.

See http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capdis.h...

EDIT:

Here's another comparison:

A typical efficient, highly optimized Lithium-ion battery has an electrode current density of about 2mA per square cm. This is virtually unacheivable to the amateur, but let's pretend you could get this kind of efficiency from your electrode area. To get a billion amperes, you'd need a lithium battery with an electrode area of 100,000,000 square meters. Please realize this is 100 square km. (or 38.6 square miles)

If each electrode cell pair were only 1mm thick, and your battery was 2m by 2m, it would stack 25km into the sky - nearly to the edge of the atmosphere!

Consider that the US Navy is struggling at the moment to supply a railgun with only 6 million amps with a gigantic government budget. Your proposal tops this by 167 times.

Also I think the current record is held by a z-pinch machine run by Sandia National Laboratories, which has achieved almost 30 million amperes.

[Edited on 9-6-2015 by Praxichys]




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[*] posted on 9-6-2015 at 08:30


I suspect trollism at play here. Two twits giggling at the thought of posting a 'question' about a 'gigamps' battery on a science forum. 'You do it' (giggle, giggle). 'No, YOU do it!' (more giggles). 'No, you' (giggle, giggle). 'Ok, I will but I'll blame YOU' (both laugh).

Good debunking by praxichys, though. :)


[Edited on 9-6-2015 by blogfast25]




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Praxichys
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[*] posted on 9-6-2015 at 08:54


Eh, I had fun with it. I also learned some stuff from the research. :)



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[*] posted on 9-6-2015 at 08:57


Quote: Originally posted by Praxichys  
Eh, I had fun with it. I also learned some stuff from the research. :)


Sure. I bet that duo couldn't string together a lemon cell between them.




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[*] posted on 9-6-2015 at 12:35


Actually you are wrong if you put enough capacitors in series you increase the maximum working voltage of the capacitors and maximum current at least in theory.. not like anyone can build a 1000000000 watt generator..especially someone asking advice from sm.
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[*] posted on 9-6-2015 at 12:45


Quote: Originally posted by blogfast25  
'You do it' (giggle, giggle). 'No, YOU do it!' (more giggles). 'No, you' (giggle, giggle).

Perhaps it was a 1.5 volt GiggleAmp battery they were after.

You're right though : pointless exercise.

May as well ask how to build a black hole in a teapot.

[Edited on 9-6-2015 by aga]




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[*] posted on 9-6-2015 at 12:52


Quote: Originally posted by gatosgr  
Actually you are wrong if you put enough capacitors in series you increase the maximum working voltage of the capacitors and maximum current at least in theory.. not like anyone can build a 1000000000 watt generator..especially someone asking advice from sm.

Or, more accurately (i.e. you're wrong) you'd increase the maximum working voltage and not the maximum possible current.

You'd put them on parallel for that or have the laws of physics changed recently ?

Edit:

You're totally right on the second point.

[Edited on 9-6-2015 by aga]




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[*] posted on 9-6-2015 at 13:25


Current discharge is I=Vmax/R(e^-τ/RC) if I'm not mistaken.... where exactly do you see that current is not increased?? taking the limits τ=0
Imax=Vmax/R , also the resistance would add up in series but not in the same rate as voltage. One would take the limit of voltage/resistance as n->inf to find whether I'm correct or not, resistance is also dependent on temperature just to make the integration a tad bit sweeter for you.:D
You should find out how real capacitors are made.



[Edited on 9-6-2015 by gatosgr]
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[*] posted on 9-6-2015 at 15:38


I have to agree with aga. If the load resistance=0, then the time constant and current are the same, regardless of how many cells are connected in series. The internal resistances of each cell are "real", and add linearly. Also, the capacitance decreases proportionately with the number of cells. Energy increases proportionately with the number of cells.

I'll sell a graphene giga-battery if anyone wants one. I'll charge $1 per amp, just to be reasonable.:)
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[*] posted on 9-6-2015 at 15:48


Quote: Originally posted by Praxichys  
You will never achieve a Gigaampere. I'm not sure you understand how much a billion really is.

A billion amps is a stupid amount of current. If you were to make a battery capable of supplying that kind of current, your conductors would have to be extremely thick. In a typical electromagnetic can crushing experiment, 14AWG copper wire EXPLODES when subjected to a peak load of 25kA. You are proposing a current 40,000 times higher than that! Doing the math, you would be able to make a round copper bar 6.5 inches in diameter and 6 feet long, explode from overcurrent. (Look up wire cross section and resistance per length) Consider that the copper bar would weigh 771 pounds and at $3 per pound for scrap copper, would cost $2300. Designing conductors to carry that safely would be incredibly expensive, not to mention HUGE.

You would also need switchgear that does not exist, not to mention the far reaching effects of the colossal magnetic field that would be generated while the current was flowing.

I think Praxichys nailed it here. It really doesn't matter what kind of capacitor bank or battery system you have. If you haven't got a copper "wire" many inches thick throughout your whole circuit you just are not going to sustain a gigamp current. And that is before you pay for the energy required to run the system for a millisecond.

I think someone has made a mistake with their decimal points here and is a factor of a million out (and probably has current and voltage reversed too.)
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[*] posted on 9-6-2015 at 17:45


Holy Guacamole, I had no idea thats how much power was in gigaamp praxichys, I guess maybe we'll have to scale it down a bit lol.

I talked to him today and we had a somewhat productive meeting lol, determined were going to use aluminum and graphite as electrodes I believe and now were back to whatever the solution is going to be comprised of to made the desired electrolytic environment.

There is sooooo much more to this then I could have imagined, praxichys you definitely lost me a few times, but I'll start googling words I don't know now haha. Hope I haven't pissed anyone off by being too new, I was taught theres never a stupid question in school and abused the hell out of that expression to the point I think I annoy most of my teachers.

That Z pulsed power facility looks really cool btw!




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[*] posted on 9-6-2015 at 18:05


Quote: Originally posted by Tungsten.Chromium  

I talked to him today and we had a somewhat productive meeting lol, determined were going to use aluminum and graphite as electrodes I believe and now were back to whatever the solution is going to be comprised of to made the desired electrolytic environment.



You want to look at magnesium/saline solution/air cells: easy to make, better than Al, very light weight, over 1.5 V (on mine anyway).

Start with a few (plenty designs on teh Utoobs, I imagine), then string'm together (series) to increase power generally and see how far you can push it.

Report here, photos an' all, we all want to learn. :)

[Edited on 10-6-2015 by blogfast25]




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[*] posted on 9-6-2015 at 23:04


Quote: Originally posted by WGTR  
I have to agree with aga. If the load resistance=0, then the time constant and current are the same, regardless of how many cells are connected in series. The internal resistances of each cell are "real", and add linearly. Also, the capacitance decreases proportionately with the number of cells. Energy increases proportionately with the number of cells.

I'll sell a graphene giga-battery if anyone wants one. I'll charge $1 per amp, just to be reasonable.:)


Time constant and current are not the same. caps in series->Taking the units are ohms, volts and V=V0*x , R=R0*x and Imax=V0/R0.
So you should connect them in parallel as I said first for equivalent capacitors Imax=V*n/R where n the number of caps, if V=100000 volts
and R= 100 Ohms then you need 1000000 caps.

The capacitance has nothing to do with Imax see the formula for current I gave you .

[Edited on 10-6-2015 by gatosgr]
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[*] posted on 10-6-2015 at 00:09


How do you make a black hole in a tea pot?


beavis-and-butthead-tech-support-3.jpg - 40kB




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[*] posted on 10-6-2015 at 03:07


How do you make a tea pot in a black hole?
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[*] posted on 10-6-2015 at 03:14


How do you make a pot hole in black tea?

(Ok, I'll shut up now.)
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[*] posted on 10-6-2015 at 05:05


You nailed it.
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[*] posted on 10-6-2015 at 05:36



It done simalarly to a black hole in a kettle (said the disgusted pot).

If one were to obtain a capacitor with cooled superconducting plates and leads. Perhaps dielectrices do not store charge at those temperatures.
Ampers law would also be a problem for the large current.

[Edited on 10-6-2015 by jock88]
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[*] posted on 10-6-2015 at 21:13


Will you use this mega-bat to run your time traveling car?



We are chemists , we bring light to the darkness. Knowledge to ignorant, excitement to the depressed and unknowing. we bring crops to broken fields and water to the desert. Where there is fear we bring curiosity.

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