Vanadium Redox Battery - Current Status

[rnbraud]

Hello All,

New to the newsgroup, and have been absorbing it all for the past few weeks.

Geek by trade, tinkerer at heart.

I ran across an article awhile back about a Vanadium Redox Battery. Basically, a liquid electrolyte which can be charged up and stored "indefinitely".

Looks like all of the research took place back in the late 90's.

Just curious if anyone here has heard of it. Does it work as advertised? Seems like a perfect candidate for a homebuilt system.

Thanks.

[wpowokal]

Yes

http://www.ceic.unsw.edu.au/centers/vrb/

Last contact I had with the makers they were too buisy with indudtrial instalations to be interested in donestic installations.

Maybe they are not all they are cracked up to be.

allan down under

[Drives]

I am unaware of the Vanadium Redox Battery, however I saw this.

It may be of interest.....Anybody have any decaying radioactive material laying around? :-)

http://www.technologyreview.com/articles/05/06/wo/wo_061605brown.1.asp

[JW]

Hi Rnbraud,

 By nature, most of all of the batterys, utilize the mechanism of reduction/oxygenation(redox). And the charge/discharge schedule has a limited life-span of so-many cycles(charge/discharge/cycles). most batterys work off of hydrogen evolution and specific gravity.

 That's quite a claim about indefinitecy, with regards to the Vanadium battery. Dont know too-much about this, but I would, off hand relate, vandium to cadmium or chromium salts which are very toxic. However there are chrome/vanadium hand tools, so im stumped....

never heard of it.

Welcome to the board.

JW  

[JW]

Seems to me, a very large capacitor, with the right-type of 'resistive load' could accomplish the task 'of-a-time-period-indefinte-in-between charge's'. This completly negates self-discharging. already capacitors can guarantee innertness, of such a design parameter, such as would be disired for a home application. I guess the advantage would be the extended capacity of state-of-charge(redox), wheras a capacitor bank capable of doing anything useful for a homepower system would halve to be huge. A battery that never discharges once its charged, would be quite infact impossible. neat topic.

JW  

[JW]

uknow,

 'if' the electrolite was stored in a separate insulative container, this could prevent the plates from selfdischarging the battery electrolite. There is another type of battery that uses this type of methology, I believe the electrolite is common saltwater(nacl added to h2o), and the plates are aluminum and carbon, the alu-cathode/anode(not sure which) is spent during discharge. Would fit your application, and you could guarantee inertness while handling the electrolite. There was some other battery available that worked simular in fashion, it spent both metal plates during discharge aswell, but used no carbon "air" plate.

 JW

[Ungrounded Lightning Rod]

Looks like they just moved from the university to a startup last year.  That could explain the recent silence.  And might bode well for this stuff coming on the market in a couple more years.

Building commercial stuff for power companies - like the "portable" (i.e. housetrailer size) substation-replacement they talk about - may lead to debugging of their designs and processes and getting them over the startup money hump.  Next step would be providing power storage/backup for telecom remote sites (like cell towers).  That gets them into the size, reliability, maintainence ease, and unattended operation capability that is appropriate for home systems - though able to sustain a somewhat higher  (but not prohibitively higher) price-point.  Once that market saturates they'll be looking to expand, and home systems are the logical next step.  (Vehicular applications have more design hurdles and SHOULD come fourth - though the price point might move them up in the line.)

One really great thing about the technology:  Since the electrolyte for ALL the cells is stored in common tanks and circulated through common plumbing, you don't have to charge and discharge at the same voltage.  You can build a stack with a bunch of taps, pick the power off at the output voltage you want, and charge with the input voltage you have available.  That's great for both solar and wind.  (With the latter you can switch it up and down the stack as the wind speed changes to maximize your generation and/or limit the load on the mill to just under thermal troubles.)

The 80% input/output efficiency, unlimited electrolyte life, and replacable membrane lifetime of 8 years or better (with the membrane inexpensive once it's in mass production) should make for a good system for home energy storage once the initial cost is right.

[fishfarm]

Try VRB Power.

http://www.vrbpower.com/energystorage.html

The other thing (besides the charge/discharge flexibility) I like about the system is the scalability. If you want to increase the storage capacity, you get larger tanks and more electrolyte.

[rnbraud]

Thanks for all of the replies.

I hadn't taken into account that the technology was "sold" to a start-up and that would account for the "silence" since the late 90's.

From what limited info I have read, the system doesn't seem too complex, however, it is not "passive" like batteries.

The controller and pumps wouldn't be to hard to create. Since the electrolyte solutions isn't too toxic, if that is possible, it would seem PVC or some sort of plastic could be utilized for the tanks, piping, and pumps.

The complex part, at least to me, is the "stack". Looks very similar to Fuel-Cell membranes. Need to do a little more research on that, but the only exotic material seems to be the ion exchange membrane. Everything else in the stack looks like plastic, copper, and either felt or kevlar.

I am just a newbie, but the idea is fascinating to me and seems to be the holy grail of battery storage for home systems.

Later.

[wpowokal]

http://www.hydro.com.au/Documents/Renewables%20Development/5882Roaring40s.pdf