Re: AGV (Automated Guided Vehicle) NiCd (Nickel Cadmium) batteries reconditioning

Dear Ted,

Thank you so much for your reply!! You are right, they are vented :) I
have to check one in a while if there is enought water inside or not :)

At the following document:

http://www.hoppecke.de/upload/docs/FNC_Brochure_Eng_09_00.pdf

Hoppecke people say that you never need to change the electrolity
because

With continuous battery power supply with float charge FNC® batteries
have a service life of up to 20 years. Because of the graphite-free
electrodes, no electrolyte change is necessary during their entire
service life. The FNC® battery is also distinguished by its cycle
resistance (over 2000 cycles under DIN), its extremely low internal
resistance and a high energy density.

They also state there that:

The positive and negative electrodes consist of nickel fibre-structured
elements with graphite-free active material. The three-dimensional
fibre structure comprising a nickel fibre composite is extremely
elastic. Mechanical stresses and volume changes during charge/discharge
cycles are therefore absorbed by the electrodes.

I tried dumping out the electrode in one of them, but... oh my....
there was SO MUCH ashes inside... then I went to an electron microscope
and found out that this is active Cd from the electrode!! I got loose
and felt down ;( And... regarding K2CO3 formation, would that be
possible since my cells are graphite-free ?

I cycled the cells individually around 5 times (I attached a 1.5ohm
resistance on each individually) but did not disconected the batteries
in series, so I could recharge them easier after 2-3 discharging. The
charger I have here is fine too, it charges this 48V pack with 12A, I
could go higher, but I think thats fine, so I charge them for 12 hours
continously with the 38 - 1.5ohm resistances attached to the 38 cells
and watch what happens.

The internal resistance is mainly around 20-50 microohm, in some few
cells its above that value, some even its higher (around
100-300microohm). Next step will be to take brand new ones and measure
their internal resistance.

This cells I use on AVGs, so they get discharged around 30-50% (not
more) then we recharge them with 120A for 5-10 minutes and let them
work again, after 1 year using these cells 6 days a week for 24h, they
start getting tired :) Then I have to cicle them every once a month ;(

I'm now working on 2 - 38 cell packs to see if I can make 1 good one,
taking out the bad cells...

If I only could figure out a way to make them last at least 5 years and
not only 2-3....

I don't know if its possible to recondition these vented cells as easy
as the sealed ones (little NiCd cells - A, sub-C, D, etc... sizes used
in power tools for example)

Sincerely, Hannes

.

Relevant Pages

  • Re: Interesting technologies...
    ... Capacitors to Replace Batteries? ... capacitors charge faster and last longer than normal batteries, ... the battery's electrodes. ... and the only way to reduce charge time is to lower the resistance ...
    (rec.arts.sf.tv.babylon5.moderated)
  • Re: Does a simple home made battery demolish entire physics edifice?
    ... You have a collection of cells well known to science. ... Does a analogous,,electric induction? ... some simple cells using common kitchen compounds are made. ... at electrodes!? ...
    (sci.physics.fusion)
  • Re: Looking at electrons without touching
    ... The next funny thing they do is to use the charge Q on the metallic ... nanoparticle as an independent variable. ... from which electrodes cannot tunnel. ... the "diffusion capacitance" of a BJT base. ...
    (sci.physics)
  • Re: Battery breakthrough
    ... fabricating electrodes and charge rate is almost 100x ... And even if a battery will accept ... A revolutionary new cure for cancer, wonder drug which targets and destroys individual cancer cells, leaving healthy tissue totally unaffected. ...
    (uk.politics.misc)
  • Oxide surface layer and Kelvin connection
    ... Titanium and stainless steel electrodes are reputed to be relatively ... resistant to corrosion due to the protective oxide layer that forms on the ... the resistance of the oxide layer will add to the total ... while the other pair measures the resulting voltage developed between the ...
    (sci.chem.electrochem)
Loading