[HN Gopher] Smaller, cheaper flow batteries throw out decades-ol...
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Smaller, cheaper flow batteries throw out decades-old designs
Author : mfiguiere
Score : 91 points
Date : 2023-01-28 17:21 UTC (5 hours ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| LeanderK wrote:
| > They remain costly, though, with a capital cost of around US
| $800 per kilowatt-hour, more than twice that of lithium-ion
| batteries.
|
| I was surprised by this! Since this is not commercialised on a
| broad scale, I would have thought that the cost is nowhere near
| competitive. Twice seems very close. How close are we to
| introducing flow-batteries at a competitive price?
| vlovich123 wrote:
| > Liu estimates that the tubular design should cut the cost of
| flow-battery power modules by roughly half. Plus, all the
| components in the cell are off the shelf, and scaling up the
| reactor cell design should be easy, since it is based on a
| commonly used design in the chemical industry.
|
| So if this research pans out it sounds like very close. This
| isn't a new concept and it's mature so the probability of
| continuing savings is less than traditional battery
| technologies (eg there's new kinds of batteries coming out that
| are cheaper and more energy dense than lithium ion). However,
| at grid scale this may have additional advantages beyond pure
| cost that make it attractive still.
| LeanderK wrote:
| I can't imagine this is more mature then lithium ion
| batteries, or traditional batteries in general. They are
| everywhere in my apartment but afaik flow batteries are not
| used yet.
| neltnerb wrote:
| I agree, especially on the industrial design and
| manufacturing side. The concept has exited for ages, and I
| love decoupling power and energy density for all kinds of
| reasons (though I'm sure standard batteries are just tuned
| perfectly enough in large facilities that it's no big
| difference).
|
| But the big cost reductions don't happen because an idea is
| mature, they occur because they're being produced at large
| enough scale that lots of people have spent time and energy
| on all of the thousand tiny things that individually reduce
| the cost. The stuff in this article is borderline just
| industrial design and they're talking a 3x change in
| footprint?
|
| There has to be lots of other low hanging fruit... we're
| still improving lithium battery electrodes and each
| improvement really does improve them. The same will be true
| for flow batteries if they ever get made at enough scale.
| pfdietz wrote:
| I find that number dubious, since the per-kWh cost of flow
| batteries should be low: just make the tanks larger.
| uluyol wrote:
| It sounds like the energy capacity and power output can be
| scaled independently of one another. But as this article is
| meant for a wide audience, I think they simplified the
| discussion by making some assumptions about the desired power
| output per kWh stored.
|
| Not unreasonable. The details are always in the research
| paper after all.
| oconnore wrote:
| > showed that the battery had a charge densities of about 1,322
| watts per liter of electrolyte and a discharge density of about
| 306 W/L
|
| Isn't the relevant measurement energy density (Wh/L) rather than
| power (W/L)? I guess there's some limit on the power generated by
| a given volume of the battery, but in practice it seems like the
| main question is how big the tank has to be per MWH/KWH, rather
| than how big the power module has to be to convert that back to
| energy over the duration of the discharge period.
| LeanderK wrote:
| (I know nothing about batteries or chemistry) I think this
| research only focuses on power generation, the device where you
| combine the liquids to get energy. Changing the energy density
| means changing the type of liquid, I assume, which this
| research is just not about.
|
| I understand it as analogous to a ICE, where you have the fuel
| and the motor. But with flow batteries you can also go in
| reverse to create fuel from energy. The research featured here
| is about the motor but if you need a different energy density
| you have to change the type of fuel since that's how the energy
| is just stored in huge tanks.
| amluto wrote:
| No. From the article:
|
| > Liu and colleagues focused on redesigning the power module
|
| A flow battery separates the _power_ portion (the electronics,
| electrodes, pumps, etc) from the _energy_ portion (tanks,
| fluid). Which is not so amazing for a car or a UPS where you
| want tens of minutes to a few hours of charge or discharge
| time, but is potentially great for grid use, where a discharge
| time of days to months is useful.
| gumby wrote:
| > for grid use, where a discharge time of days to months is
| useful.
|
| Not sure I know the use case for a duration of that length.
| It's possible today with pumped hydro, but I don't think it's
| used in that mode.
|
| The DoE's "long duration storage earthshot" effort is loking
| for 10+ hours, which makes more sense:
| https://www.energy.gov/eere/long-duration-storage-shot
| michaelt wrote:
| A zero-carbon northern Europe that replaced all gas heating
| with heat pumps would benefit from being able to store
| electricity during the warm summer months, to power heating
| in the cold winter months.
|
| There are other options, of course - new nuclear plants,
| importing renewable power from countries with better
| weather, huge numbers of wind turbines, and so on - but
| cost-effective long-term power storage would address some
| issues if it was available.
| jfoutz wrote:
| The standard reply to any sort of gravity storage is
| "geography and land availability". I don't find that
| argument compelling enough to dismiss gravity storage
| outright, but I'll admit Oklahoma is pretty darn flat.
|
| Chemical storage could be a big win when a mountain isn't
| readily available. Or the land is too expensive to use for
| power storage.
| mgerdts wrote:
| Why wouldn't it be good for cars? It seems a fluid exchange
| could recharge the car, limited by how fast you can pump out
| the discharged fluid and pump in charged fluid.
|
| I have no idea whether there are containment or environmental
| challenges that make this especially hard.
| hinkley wrote:
| It's going to depend on the details. In a power substation
| space and weight are fairly flexible. In a vehicle they
| matter quite a bit. If you can build a flow battery that
| rivals solid state batteries for weight and volume, you've
| made an improvement because the fluid is swappable in ways
| that batteries are not. Batteries meant to move will move
| in a crash. Fixed batteries tend to stay put but complicate
| road trips.
|
| In a UPS the tanks and valves and pumps are new points of
| failure, as the other responder states. In a car they are
| many times more complicated than electric vehicles, yes,
| but still less complicated than ICE vehicles by far. Your
| heater has more moving parts. Hell, the emissions control
| gear is probably more complex than the entire drivetrain of
| the electric vehicle.
| randall wrote:
| That sounds like moving to a non solid state situation,
| right? One of the big benefits, imo, is removing as many
| moving parts from a car, not reintroducing them.
| mgerdts wrote:
| Surely it is more complicated. It may be able to serve
| the goal of eliminating fossil fuels from the car while
| not getting the full simplicity of (not really) solid
| state batteries we have today.
|
| It would seemingly also allow you to carry around 50
| miles of juice when you are running around town and bump
| up to 400 miles of juice when you are taking a road trip.
| This really only makes sense if the car is able to
| recharge the juice.
|
| Maybe a new hybrid model (not gas electric hybrid) could
| emerge. The base (say 50 mile) capacity is solidish state
| like we have today and a flow battery range extender
| could be filled with fluid when the extended range is
| needed. This would make it so the car wouldn't need to
| charge the fluid, if that helps.
| jacobn wrote:
| Being able to "refuel" quickly is a pretty big plus, so
| in the balance it could still be better to accept some
| moving parts in exchange for that.
|
| And it's easy to imagine retrofitting a gas station to
| all of a sudden have charged electrolyte instead of gas,
| but I'm sure that has all sorts of additional
| complexities that I know nothing about... ;)
| jccooper wrote:
| Probably adds two low-pressure low-volume pumps. Which is
| more, but not a large increase in complexity for a car.
| The driver's seat probably has more moving parts.
| imtringued wrote:
| A smaller charger/discharger simply costs less which lets you
| buy more electrolyte. This is especially relevant for smaller
| installations.
| marcosdumay wrote:
| The article is about the size of the ion-exchange element, so
| I'd guess no, it's not supposed to be Wh/l.
|
| If you want the storage density, you can look by the battery
| chemistry. But I'm not sure the article got this one right, or
| else the researchers didn't actually work on flow batteries and
| that part is only speculation.
| [deleted]
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