4 ms·

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 charge

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.

randall 4y ago
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 4y ago
  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.
  - m463 4y ago
    I could see a hierarchy of power in a car, or truck/rv. motor <-> lithium <-> flow battery the low current from the flow battery could be continuously augmenting and replenishing the lithium ion battery or even: supercapacitor <-> lithium <-> flow battery
- jacobn 4y ago
  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 4y ago
  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.
hinkley 4y ago
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.
amluto 4y ago
If one can actually make a useful economy out of replacing flow battery fluid at a station, sure. But I’m making a different point: A Li-Ion battery can charge and discharge in something like an hour. If you double the number of cells in a battery or installation, you can store twice as much energy and you can draw twice as much power. (You don’t have to provision twice as much power circuitry, but you do need to purchase that extra power worth of electrodes in the cells.) If you’re building something for which a roughly predetermined power to energy ratio (i.e. hours of use at a reasonable rate of discharge for the technology), this is fine. Similarly, if overprovisioning power or energy is not a problem for cost or weight, also fine. But for grid use, wide differences in the duration of energy storage for different purposes can make sense. And a flow battery can separately provision power and energy. This gives a possible cost benefit to flow batteries.
ilyt 4y ago
Flow batteries have way less current capacity so it could plainly not be powerful enough. It also have lower energy density so you pumping 600l of new electrolyte on the station might still give you only 200km of range
- m463 4y ago
  Could it be good for a long-haul truck? or maybe a locomotive, which is less sensitive to weight and cargo capacity?
  - ilyt 4y ago
    It kinda depends to what power density it gets. Trading say 30% range for ability to refill the truck within minutes might just make enough sense to work. But if, say, electric truck gets enough range to run the full 9 hours (max allowed driving time per day in EU for truck drivers), then it doesn't matter as trucker can do "100% of their work", get to stop and leave it to charge for rest of the day. For locomotives ? I'd imagine the simplest solution would be to have "battery wagon" ; get on the station, replace the battery wagon, and be on your merry way while it is recharging in the station waiting for next train to pick it up, at least for the long haul stuff. But capacity density still matters, if flow batteries are being close and cheaper then it makes sense, but if you need to pay slighty more per KWh but get 2x the capactity... thats 2x the range and less maintenance. Or, you know, just electric rail. It already works fine in many places. I wonder if making some hybrid solution with electric rails also being covered by solar panels (basically so same maintenance crew can manage both) would make sense So it all depends to what level of density it gets. If it is same capacity per kg but lower power there are still many places it can be used, if it is much lower it stops being sensible for moving stuff. And the price would need to be significantly below the normal batteries for anyone to even bother.
  - Schroedingersat 4y ago
    Trucks are weight limited with LFP, costs already favour electric even with NMC but the tradeoff is payload. Trains maybe, but surely the money is better spent on overhead wire? Even if tunnels/bridges/etc. can't take it you're better with just the power-buffer battery and no flow battery.

randall 4y ago

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 4y ago
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.
- m463 4y ago
  I could see a hierarchy of power in a car, or truck/rv. motor <-> lithium <-> flow battery the low current from the flow battery could be continuously augmenting and replenishing the lithium ion battery or even: supercapacitor <-> lithium <-> flow battery
jacobn 4y ago
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 4y ago
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.

hinkley 4y ago

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.

amluto 4y ago

If one can actually make a useful economy out of replacing flow battery fluid at a station, sure. But I’m making a different point: A Li-Ion battery can charge and discharge in something like an hour. If you double the number of cells in a battery or installation, you can store twice as much energy and you can draw twice as much power. (You don’t have to provision twice as much power circuitry, but you do need to purchase that extra power worth of electrodes in the cells.) If you’re building something for which a roughly predetermined power to energy ratio (i.e. hours of use at a reasonable rate of discharge for the technology), this is fine. Similarly, if overprovisioning power or energy is not a problem for cost or weight, also fine. But for grid use, wide differences in the duration of energy storage for different purposes can make sense. And a flow battery can separately provision power and energy. This gives a possible cost benefit to flow batteries.

ilyt 4y ago

Flow batteries have way less current capacity so it could plainly not be powerful enough. It also have lower energy density so you pumping 600l of new electrolyte on the station might still give you only 200km of range

m463 4y ago
Could it be good for a long-haul truck? or maybe a locomotive, which is less sensitive to weight and cargo capacity?
- ilyt 4y ago
  It kinda depends to what power density it gets. Trading say 30% range for ability to refill the truck within minutes might just make enough sense to work. But if, say, electric truck gets enough range to run the full 9 hours (max allowed driving time per day in EU for truck drivers), then it doesn't matter as trucker can do "100% of their work", get to stop and leave it to charge for rest of the day. For locomotives ? I'd imagine the simplest solution would be to have "battery wagon" ; get on the station, replace the battery wagon, and be on your merry way while it is recharging in the station waiting for next train to pick it up, at least for the long haul stuff. But capacity density still matters, if flow batteries are being close and cheaper then it makes sense, but if you need to pay slighty more per KWh but get 2x the capactity... thats 2x the range and less maintenance. Or, you know, just electric rail. It already works fine in many places. I wonder if making some hybrid solution with electric rails also being covered by solar panels (basically so same maintenance crew can manage both) would make sense So it all depends to what level of density it gets. If it is same capacity per kg but lower power there are still many places it can be used, if it is much lower it stops being sensible for moving stuff. And the price would need to be significantly below the normal batteries for anyone to even bother.
- Schroedingersat 4y ago
  Trucks are weight limited with LFP, costs already favour electric even with NMC but the tradeoff is payload. Trains maybe, but surely the money is better spent on overhead wire? Even if tunnels/bridges/etc. can't take it you're better with just the power-buffer battery and no flow battery.