Carbonfiber Alufoil selfmade DIY battery with NACO3 or Ashwater electrolyte

[hartiberlin]

Hi All,
in the last few days I have been working and published a few videos about my latest Carbonfiber and
aluminiumfoil battery cells.

Using Carbonfiber sheets and alufoil as the electrodes you can get in an alkaline electrolyte
a voltage of around 1.4 to 1.7 volts as the open circuit voltage.

Well the carbonfiber also itsself has a pretty low ohmic resistance,
only around 5 to 15 Ohms per cm distance.

So using carbonfibersmakes it easy to build such a cell, cause then only the alufoil will be consumed.

For the electrolyte you can use several different salts, like Pottassium Carbonate ( K2CO3) , Sodium Carbonate
or also called Washing Soda ( NaCO3) or also firewoodahes  or coalashes in water. The latter are mostly K2O or Na0 or CaO
salts and give mixed with water also some KOH NaOH and when the CO2 from air enters, these are converted to Carbonates,
so you get free Carbonate salts.

So if you don´t have access to any Washing Soda, which could be got in any bigger supermarket and it is cheap ( around 1,50 US$ per 500 Gramms)
then you can just make a firewood and collect the ashes from it and put them into tap water to get the desired alkaline electrolyte.

Be careful not too make the concentration too high with the ashes in the water, cause then the KOH concentraion  will be too high
and zje electrolyte will eat away your alufoil pretty fast and produce flammable hydrogen gas ! So be careful !

Also be very careful, that you will not get any of the ashwater or other electrolyte into your eyes as it can easily blind you !
So please wear safety goggles when you handle the electrolyte !


Well, as I did not yet have built a Joule Thief circuit, I had to put 4 cells in series to be able to light a 1 Watts LED chip reasonable well,
so you could still read a book during nighttime !

These cells runs now already since more than 48 hours and the voltage is still at around 2.55 Volts on the LED chip and the current is still
at around 4 milliamps !

Surely the inner resistance of the cells are pretty high compared to the standard NimH AA cells.

Standard NiMH cells have an inner resistance of around less than 1 Ohm.
My carbonfiber cells unfortunately have an inner resistance of around 150 to 300 Ohms,
depending on their age and some other factors.
So the power output is much smaller...

But it can be increased with different methods I will still try.

At least you can easily build with these methods your own battery cells that are able
to light up LEDs.


Here are the Videos:


Carbon fiber sheet Aluminium foil Selfmade DIY High Output battery
https://www.youtube.com/watch?v=KLjSH8O3cWw

1 Watt LED Light bulb testing
https://www.youtube.com/watch?v=opZP6ScWgmE


Measuring ohmical resistance of different carbon fiber sheets
https://www.youtube.com/watch?v=hWXv2zFiXXg


Despeckle Salt cell testing - carbon fiber aluminium cell
https://www.youtube.com/watch?v=6_fZURgMZYc

Carbonfiber alufoil cell - building up a rollup cell
https://www.youtube.com/watch?v=odDwa5-qIPI

pickup electrode for the carbon-fiber-alufoil cell and measurements
https://www.youtube.com/watch?v=ahJQgPocsUk


3 cells in series - carbon fiber alufoil cells lighting up LED
https://www.youtube.com/watch?v=ZYA48sMJZoE


4 carbon fiber alufoil cells in series running LED
https://www.youtube.com/watch?v=wNsyIaT_CEA

Evening light from the 4 carbonfiber-alufoil cells
https://www.youtube.com/watch?v=FokluCS-2do

24 hours runtime later - carbonfiber alufoil cells raised voltage on LED
https://www.youtube.com/watch?v=ZAQuc8DeJRQ


Hope this helps.

Regards, Stefan.

[hartiberlin]

Toay I measured the inner resistance of the cells.
These have now an open circuit voltage of around only 0.77 Volts
when you disconnect the LED load and let them stay for half a minute or so...

The shortcircuit current through an ampmeter was 5.5 milliamps and the voltage across the ampmeter was then 9 MilliVolts.

So the Inner resistance of such a cell has:
0.77 Volts - 0.009 Volts / 5.5.milliamps = around 138 Ohms.

So this is why these cells are so much less powerfull then the NiMH type batteries.

The inner impedance is just too high.

So this can be fixed by either using more conducting lampblack or graphite powder on the surface of the carbonfiber
and additionally putting a silverwire or stainless steel mesh onto the carbonfiber to make the electrode resistance smaller
and  make a better conducting electrolyte.

Regards, Stefan.

[hartiberlin]

Today I also tested, if I can not just take stainless steel dish scrubber wool
instead of the carbonfiber sheets and Voila, this also works in an alkaline electrolyte.

Although the open circuit voltage with Washing Soda - Water electrolyte  is then only around 1.15 to 1.20 Volts,
the shortcircuit current, when the cell is new, also begins over 100 milliamps, from a water glas type sized cell.

So as Carbonfiber sheets are pretty expensive and not so easy to get  we can now also use
just stainless steel scrubber dishwashing wool, which si also available in every bigger supermarket.

So we have 2 very cheap electrodes, where only the Alufoil is consumed and the electrolyte is also free
from firewood or coal ashes..


Next I will first build a much bigger single cell now to have more surface area and thus less inner resistance
and then also build a fitting Joulethief circuit, that is able to power some good LEDs that will work from under 1 Volts
Voltage.
SO you only have to build one bigger cell which is also easier to handle and care about.

Regards, Stefan.

[Pirate88179]

Stefan:

Nice work.  I have been following your videos and, I do believe that just a simple, basic JT circuit will get you a lot of usable light from your cell.  The greatest thing about your design is that it is so simple, and cheap, to replace the anode as it is consumed.

Have you thought about taking the al. foil and fold a bunch of it together and hammer it into an almost solid block to see how long that lasts?

In other words, you could take an entire roll of that foil and keep folding it and hammering it into a very solid square form that should last quite a while.

I look forward to seeing your results with these experiments.

Bill

[Magluvin]

Nice work Stefan. I like it.

I work with carbon fiber from time to time. Car projects.

Ive taken a strip of the fiber and put it across a 12v battery and it glows like a space heater. So its fairly resistive.

I tried some hydroxy experiments with it as a plate. I found that making a connection to it is better done across the cut ends of the sheet, using a thin metal folded over long ways and insert the cut edge of the carbon sheet and crimp the metal down so to make contact with all the individual threads of the weave.  If you connect to just a corner of the sheet, the output(or input in my case) is limited through all the resistance of the carbon. And maybe with reactions in the cell, the physical connection between the weaves might be compromised over time. The hydroxy cell turns black fairly quick, I suppose carbon coming apart in the process.

To think about it, maybe there is a good conductive glue or epoxy and glue a bare wire to the .edges of the strip, providing more current output capability. Or in my case more input.  You can use solder braid a a wire as it is very flat and flexible, for rolling one together.

Also once you layer the cells, you will be using both sides of the materials an produce even more. Like if you roll what you have, laid out flat, and roll it into a cylinder, the layering will happen naturally and more output. Spiral cells. Havnt tried to solder carbon.

Mags

Have you tried applying a charge to the cells to see if they can be brought up to a higher potential?