Fully discharge a battery all at once?

[Colic]

Is there some way to force common batteries to use up all of their stored energy at once?

[md65536]

Probably, but I doubt it would be a battery afterwards.

 

Even if you short it, it will still take some time to discharge, and will probably damage the battery. See http://www.electro-tech-online.com/threads/shorted-battery-what-happens.128024/ for some interesting related comments.

 

If you destroy the battery you can probably remove its stored energy. Say you vaporize the battery with enough energy, you might make it impossible to get any electrical energy out of it (as long as you don't include added heat etc as part of its "stored energy").

[Sensei]

What do you mean by "at once"?

In 1 second?

In 1 milisecond?

In 1 nanosecond?

 

f.e. NiMH accumulator AA has 1300 mAh

which is 1.3 Ah

which is 4680 C

One electron has charge 1.6*10^-19 C

so accumulator has 4680 C/1.6*10^-19 C = 2.92*10^22 electrons.

 

You would need to make some capacitors array, and change voltage from 1.2 V to say 230 V, and then plug some common heavy energy consuming device such as light bulb. In theory, if I calculated right, and without loosing energy for conversion (which is impossible), 75 W light bulb should work on mine NiMH accumulator for 75 seconds.

 

[Colic]

By at once I mean any duration of time that is too small for a person to distinguish separate events between, a time smaller than human reaction time.

What you're saying to get 230 volts kind of sounds like lining up 20 AAs in a series, I don't need to do that, there's 60-70 bolt batteries that can fit in your hand. But some batteries are particularly small like those small lithium disk batteries, it wouldn't be too much of problem to line a bunch of them up but I'd still only be able to get like 30-60 volts. Basically I want a high voltage and high stored energy in a small area that I can use up really fast initially in the form of electrical energy.

Edited January 2, 2014 by Colic

[Sensei]

What you're saying to get 230 volts kind of sounds like lining up 20 AAs in a series,

 

 

20*1.2 V = 24 V

 

Array of capacitors that are filled when they're parallel connected to DC, and then switching them to serial circuit, is normal procedure of making high voltage from low voltage source.

Marx generator is example of such setup

http://en.wikipedia.org/wiki/Marx_generator

Another one is Cockcroft–Walton generator

http://en.wikipedia.org/wiki/Cockcroft%E2%80%93Walton_generator

[md65536]

http://electronics.howstuffworks.com/capacitor2.htm says that an AA battery holds about 2.8aH, and would need a 10080 F capacitor.

 

Three of the biggest of these http://www.maxwell.com/products/ultracapacitors/products/k2-series should do it.

 

However, 2.8aH is 10080 amps per second for 1 second, and those supercaps max out around 2 amps. So you'd need 5000 of them for 1 sec discharge? Or maybe 50000 to exceed human reaction time. There are probably more suitable high-amp capacitors.

 

Another thing to think about: Livermore's Petawatt laser maxed out at 680 joules for a trillionth of a second https://www.llnl.gov/str/MPerry.html and an alkaline AA battery holds about 9000 joules. You'd need 10x the capacity but about a 10 billionth of the wattage.

Edited January 3, 2014 by md65536

[Colic]

Alright thanks

[md65536]

Uh oops I was off by a bit, only a factor of a thousand. Those supercaps max out around 2000 amps! So probably 50 or fewer for a AA battery would exceed reaction time. Probably 1 supercap would suffice for a small button cell.

[Sensei]

But he wants high voltage in the first place. High capacitance often goes with low voltage.. What you showed K2 series has just 2.7 V.. He could just use battery instead, result would be the same.

[decraig]

The rate of discharge is limited by the battery's own internal impedance.

[davidivad]

Is there some way to force common batteries to use up all of their stored energy at once?

 

batteries have an internal resistance. have you ever noticed that when you subject a battery to a heavy load it gets warm? discharging a battery too quickly destroys it. some batteries can be discharged quicker than others. compare a plain battery to a nicad battery and you will understand. this is why they use those batteries in remote controlled airplanes. they can put more out in a given amount of time. cpacitors allow you to slowly store energy until you have a desired amount. you can then dump the energy very quickly. remember that capacitors are not made for long term storage.

[Didymus]

Please tell us he didn't just tell you how to make a cheap backyard stun gun....

 

Keep in mind, capacitors -can- kill people. Rapid release inherently implies a lot of amperage at once. That's instant death. Stun guns are made "safe" at very high voltage because they have extremely low amperage.