Author Topic: Graphite Foam Battery  (Read 1607 times)

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fishfarm

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Graphite Foam Battery
« on: January 27, 2006, 12:45:42 PM »
I saw this the other day and thought I would throw it into the battery technology mix. No idea on availability or cost, but the reduced weight would be good for EVs.


http://www.powermanagementdesignline.com/news/177101291

« Last Edit: January 27, 2006, 12:45:42 PM by (unknown) »

willib

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Re: Graphite Foam Battery
« Reply #1 on: January 27, 2006, 06:34:50 AM »
Thats pretty cool..

i havnt found the principle of how it works yet..

it just says that graphite foam is used as an electrode..

maybe a patent search will produce better results.
« Last Edit: January 27, 2006, 06:34:50 AM by willib »
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Ungrounded Lightning Rod

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Re: Graphite Foam Battery
« Reply #2 on: January 27, 2006, 12:13:43 PM »
Sounds like what they're doing is using graphite form for the supporting strcuture of the plates, then plating a lead surface over it.  The lead surface reacts normally.


But unlike conventional batteries (where the supporting structure itself is lead and participates in the reaction, swelling, warping, crystalizing, flaking, or disolving) the graphite supporting structure's shape and bonding isn't affected at the voltages, temperatures, and chemistries involved.  So it remains intact.


The battery can probably be overvoltaged to drive off sulfation, or perhaps even to completely plate the lead over onto one plate or the other temporarily to break up even large third-stage crystals, without damaging the underlying structure.


The graphite structure, like activated charcoal, would have a HYSTERICALLY large surface area.  If you don't palte enough lead onto it to clog it, this would allow much higher operating currents and charge/discharge rates, too.


Main downside would be the resistance of graphite.  But it's low enough that it shouldn't be a significant problem.  (Remember that carbon-zinc batteries have a graphite rod for one electrode, connected to metal only at one end, and they work just fine.)

« Last Edit: January 27, 2006, 12:13:43 PM by Ungrounded Lightning Rod »

Ungrounded Lightning Rod

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Re: Graphite Foam Battery
« Reply #3 on: January 27, 2006, 12:14:16 PM »
Typo:  Graphite FOAM, not FORM.
« Last Edit: January 27, 2006, 12:14:16 PM by Ungrounded Lightning Rod »

willib

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link to the patent
« Reply #4 on: January 27, 2006, 01:44:21 PM »
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsea
rch-adv.html&r=1&f=G&l=50&d=PG01&p=1&S1=%28%28%28graphite+AND+foam%29+AND+ba
ttery%29+AND+firefly%29&OS=graphite+and+foam+and+battery+and+firefly&RS=
« Last Edit: January 27, 2006, 01:44:21 PM by willib »
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Clifford

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Re: Graphite Foam Battery
« Reply #5 on: January 27, 2006, 06:43:28 PM »
Interesting idea....


As far as I can tell, the discharge current (CCA) in the batteries isn't a big deal for RE.  In fact, in many senses it is kind of scary to think that one could have 2000 to 5000 Amps of current stored in a relatively small battery array.  The ability to recharge may be a slightly larger issue.


For RE, the bigger issue is reserve capacity and battery life which may or may not be improved by the graphite.


As far as conducting...  one would probably get a mix.  I would assume there would always be a partial covering of lead on the surface which would augment the conductance of the electrodes.  Perhaps part of the graphite could also be plated with gold or silver to augment the conductance.


What I can see with increasing the surface area dramatically would be the ability to make a very powerful battery in a small package...  like what the world is searching for with cell phones, computers, hearing aids, and etc.  

« Last Edit: January 27, 2006, 06:43:28 PM by Clifford »