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An open-source flow battery kit

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Re: An open-source flow battery kit

#41

Post by Retric »

Workaccount2 wrote: post #34
Retric wrote: post #28

Earlier quoted context omitted.

1 liter of electrolyte is nothing for a flow battery, the smallest scale they become a serious competitor is ~10m3 (10,000L) tanks which are ~(7 foot X 7 foot X 7 foot). Start taking GWh of storage and lithium ion technology gets really expensive and has a lot of associated risks. Flow batteries on the other hand don’t need to worry about a single cell failure resulting in a fire which then spreads.

The amount of electrolyte doesn't scale the available power though, only the available energy.

That just means you get to scale it independently.

While they both need to scale the amount of DCAC inverters based on peak power demand. If you want to discharge over 16 hours you’re using 2% of lithium ion’s peak power output and need a huge mess of wiring to move power from each internal cell to that inverter + complex battery packs with individual electronics cooling etc.

Flow batteries on the other hand can use a single pump (+ redundancy) and fat pipe to supply a huge array of ion-exchange membranes which then sit next to the inverters.

Re: An open-source flow battery kit

#42

Post by Dylan16807 »

Workaccount2 wrote: post #35
Dylan16807 wrote: post #22

Earlier quoted context omitted.

Unless you're flying a drone, you don't need to match the power and energy capabilities of lithium ion. On top of that, you don't have to match the internal resistance to match power. If you have plenty of material to absorb the heat, then you can tolerate more percentage points of loss. In particular, while lithium ion batteries can be built to sacrifice discharge rate for a bit of extra capacity, something like a 3…

I see what you are saying, in reality the right energy storage is very application dependent. The crux of my argument is that I cannot think of many applications where a commercial grade flow battery is the best choice, much less a single application where a DIY flow battery is the best choice.

My main point is that while it definitely has to compete on price, it doesn't have to compete on price while also making you buy ten times as many cells.

Many elements of being the "best choice" are thresholds. Excess performance doesn't make it better. Price is extremely important, but power density is not so important for most use cases. So if it's even slightly cheaper, expect to see a lot of it.

Re: An open-source flow battery kit

#43

Post by 0cf8612b2e1e »

briffle wrote: post #33
0cf8612b2e1e wrote: post #27

Earlier quoted context omitted.

… if you are looking to scale this to a couple of hundred megawatts, just stop reading and thinking about this now I thought that was one huge appeal of flow batteries is that you can basically infinitely scale them. China has a 100MW installation (potentially more since this 2022 report) https://www.pv-magazine.com/2022/09/29/china-connects-worlds...

These guys in the US make a 500kwh version, that can run at 75kw of discharge power across 3 phases, and its a single shipping container: https://essinc.com/energy-warehouse/ It doesn't seem like it would take up that much space to have 200 shipping containers sitting somewhere, i'm pretty sure the Home Depot distrubution center in our town already is close to that in their parking lot (yes, you would want them not o…

That’s incredible. I wonder what are the costs relative to a grid scale battery of equivalent size.

I only wish they made one that were barrel sized and fit for consumers. Worst case, you have a leak vs a home battery fire.

Re: An open-source flow battery kit

#44

Post by gwbas1c »

Workaccount2 wrote: post #2

I cannot see how this is useful outside of being a fun student learning program. From the data it appears a battery with 1L of electrolyte provides about 18Wh of energy. Mind you this is at ~1.2V, which isn't especially useful without a boost converter. With a boost converter though you would need a low internal impedance from the battery, which I highly doubt is any good with a paper membrane (from what I understand…

> I just don't see what this is trying to do outside being a learning experience for students.

Perhaps one of those students will figure out how to make a useful large scale flow battery? I have solar, and the missing piece is being able to store electricity for the winter.

Perhaps the person who figures it out learned something from a project like this?

Re: An open-source flow battery kit

#45

Post by marcosdumay »

almostnormal wrote: post #40
Workaccount2 wrote: post #34

Earlier quoted context omitted.

The amount of electrolyte doesn't scale the available power though, only the available energy.

Energy storage is the problem that needs a solution, e.g., storage from summer to winter.

Annual and long-tail storage are both problems that need solving, and fuel cells do look like a possible solution. But it's not clear at all what the winner will be for those applications.

Even hydrogen is competitive here. IMO, more competitive than that battery chemistry on the article.

Re: An open-source flow battery kit

#46

Post by hosh »

_alex_ wrote: post #20

I dont know anything about flow batteries, but some quick searching leads me to believe that there are two tanks of electrolytes with pumps that pump them along a membrane and then you get power across the membrane. In this small battery kit, is the idea that the battery provides enough power to both operate all its own pumps/electronics, and then output usable power? Does anyone know how much power you'd be able to…

Flow batteries have some fantastic properties. Their energy output and capacity can be scaled independently. They are safer and can be made from material that are easier to source.

They are also have high upfront costs and poor energy density, so there have not been much application outside of grid-scale deployments. Getting something practical for onsite commercial, residential, and vehicular applications have been something aggressively pursued. (Solid-state batteries being another battery tech that is also pursued).

So for someone to make a open-source DIY flow battery that can scale well can change a lot of things.

https://www.wevolver.com/article/what-is-a-flow-battery-a-co...

Re: An open-source flow battery kit

#47

Post by kragen »

moffkalast wrote: post #37
RobotToaster wrote: post #29

Earlier quoted context omitted.

Home 3d printers started as repraps that could barely print a shot glass.

That wasn't because it was a proof of concept tech, but because Stratasys was effectively patent trolling it since the 80s.

it's possible the necessary inventions would have happened earlier without the patent problem, but the minimug era of reprap was not simply reproducing existing fdm machines; they were having to figure out a lot of things nobody had figured out before, like parts cooling fans, pla to use lower temperatures and avoid the need for a heated build chamber, threaded rod truss gantries, avr g-code interpreters, and eventually auto bed leveling, pla pinch extrusion, etc. there are things people could have told them, but if they'd done everything in the safe conventional way they would have ended up with a two thousand dollar machine

Re: An open-source flow battery kit

#48

Post by kragen »

KennyBlanken wrote: post #18
kleton wrote: post #15

What is the Coulombic efficiency? A paper membrane probably leaks a lot, but a state of the art ion exchange membrane probably runs $1k/m2.

It's in the blog. The author mentions finding that matte inkjet paper worked fairly well. There are much cheaper membranes; ESS for example uses a membrane that is used by lithium ion batteries (I think) and thus is commonly available and very inexpensive.

where in the blog?

Re: An open-source flow battery kit

#49

Post by kragen »

hlieberman wrote: post #31
KennyBlanken wrote: post #17

I've been watching ESS (they make a non-toxic iron flow battery system) for years and been really frustrated that they have made essentially zero progress deploying the technology, with less than half a dozen deployments. The technology looks great, but they seem annoyingly incompetent at marketing/selling their product...or are just holding out for "whale" customers, refusing to work with anyone except microgrid (ie…

The author actually talks about ESS in a comment to the linked blog post from the article. Apparently their battery generates a ton of H_2 that needs to be managed. That could easily be the sort of thing that only is possible/realistic at large scales, thus eliminating sizing the battery down indirectly. https://chemisting.com/2024/03/15/an-open-source-diy-flow-ba...

you can just vent h2 to the atmosphere

Re: An open-source flow battery kit

#50

Post by ForOldHack »

smallerize wrote: post #39
ForOldHack wrote: post #24

Earlier quoted context omitted.

This looks like a toy, but its INSANELY COOL! You build a proof of concept? This technology is cool. I was at a tiny house competition, and we were using golf cart batteries, and the winner: The University of Santa Clara, CA: "The house stores its energy using saltwater batteries, the only batteries in the world to be Cradle to Cradle certified." https://www.tinyhousebasics.com/revolve/

That article is from 8 years ago. Saltwater batteries are hard to find right now since Aquion quit making them and I don't know of anyone retailing Salgenx yet.

Wow! You have totally done your homework. Totally. Yes, Aquion went out of business, and Salgenx is not on the market yet.
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