diy solar

diy solar

weird liquid battery

curiouscarbon

Science Penguin
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Jun 29, 2020
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was internet searching around for solderless battery kit (recommendations welcome btw) and ran across this video about a Ca/Sb chemistry battery. warning. the title is so clickbaitey and bad. and the comments section looks totally fake.


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seem legit to anyone?

i’ll stick to LiFePO4 for now :)
 
Same here.
I probably would change my setup when it needs replacement for Epson battery.

I know. Massive. And not as good efficient as LiFePO4.
There are cells functional for over 85 years now.
Normal lifespan +50 years.
And not sensitive as LiFePO4.

Price is probably about the same.

But over 10-15 years when my cells need replacement...
Who knows
 
Other than the high temperatures, the problem with liquid-liquid batteries is probably the electrolyte layer has to be somewhat thicker than other technologies, so that slows ion movement. For large storage-to-discharge (e.g., solar or utility) that might not be an issue. Not for cars ;-)
Update: The Standford video says the rest current is 600 amps per cm², so possibly not an issue.

Sounds like it's exothermic on discharge, so the charging also has to add energy to heat the cells which will reduce round trip efficiency.
Insulation could help reduce that, as the net thermal loss should be minimal, but then the batteries would have a large operating temperature range which will undoubtedly affect efficiency (the claim is 75 to 80%).

How hot is hot? Here are melting / boiling points for the elements:
Antimony: 1,167°F / 2,888°F​
Calcium: 1,548°F / 2,703°F (Annode)​
Calcium chloride: 1,422°F / 3,515°F (Electrolyte)​
Magnesium: 1,202°F / 1,996°F​

So the operating range sounds like it would be around 1600 to 1500°F. Except they did some alloys... so the actual temperature is around 900°F. That's a lot of lead mixed in.

They should be inexpensive to manufacture since the layers are self-separating, just drop the solid metals in as bricks, seal it up, and ship. Not seeing the claims of any large economy of scale as the manufacturing should be simple. What it's packaged in needs to be non-reactive to the metals. Glass melts at 2800°F, so possibly glass-lined carbon steel (2600°F melting point) shells? It's not a crazy hot temperature for a utility. For example, a coal furnace runs around 3900°F.

Funded by the Gates Foundation. 80 Ah in a 4" cube, a 53' semi-trailer is 2 MWh. 300 mA/cm² and nearly zero degradation (0.00009% fade/cycle) after 1000s of cycles at 93% DoD. So that's really impressive (99% capacity after 3650 cycles).

They're thinking at scale they'll be below $500 kWh, so still more than pumped hydro, although it's unclear from the video if that's a levelized lifetime cost. But, they're working on "Zebra Unchained" and thinking it'll be $25 kWh and a 4" cell would be 240 Ah, so a semi-trailer size would be 6 MWh. $25/kWh for energy storages changes everything, it would be nice if they can pull it off.

Also see discussions/videos:
MIT Video
Luddite Video
 
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LiFePO4 can be around $75-85 per kWh, that is already impressive.
Probably +3000 cycles (I haven't done it yet, seeing is believing)

Edison is huge, and after initial purchase, fairly cheap to "repair".
I believe it needs new liquid every 10 or 15 years to stay in optimal condition.

After reading up on the subject, I was surprised they are still produced, and for energy storage as solar, if you have a spare room or garage, a once in a lifetime purchase. Almost maintenance free.
They will outlive your Solar panels.

Space is probably the reason they aren't used much.
Besides that they are fairly unknown to the public.

I researched before going down this road and reflow battery was one of my choises.
Not in my price range.
The salt water battery was bankrupt.
Easy and available was lead acid.

Hot Thailand and defective EASun hybrid that charged 48v setup with 72v was quickly the end of it, and now have 1000 kg old lead.

Now LiFePO4.

I will start looking again when my setup starts behaving badly, too low capacity storage.
With +1000Ah, that will take a few years.
We could manage with 400Ah if needed.

If there isn't a real replacement for Epson by then. Thatwill be my choice.
We do have the space, and 75-85 efficiency is fine for us.
Solar is cheap, we always can add a few extra panels to compensate.
 
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