10 ms·

Why can't we make liquid batteries yet, so you can tank "gel", discard the old gel through the bottom of the car at the "gas" station.

by tiku 5y ago

kumarvvr 5y ago
Power to weight ratio, in such systems, is very low, at current technologies.
api 5y ago
We can but my understanding is that there are issues, one of them being that these compounds are horrible things that you don’t want spilling or getting on people. Any car tech has to pass what I call the “rusty pickup test.” It has to degrade gracefully and remain useful and safe enough for use. Current EV tech passes that. I can totally picture a rusty old F-150 Lightning with aftermarket repairs.
- southerntofu 5y ago
  > remain useful and safe enough for use. Current EV tech passes that. Does it though? I heard exploding/self-burning batteries, which were a problem with some cellphones, were a much bigger problems with electric vehicles? I don't have data on how often it happens though, but that makes me skeptical.
  - api 5y ago
    Gasoline fires happen all the time. They just don't make the news because they're not new. Like EV battery fires they are statistically rare. We got pretty good at handling incredibly toxic and flammable liquid fuels on a routine basis and we can do this for high energy density batteries too.
  - devonkim 5y ago
    It’s worth considering the status quo of ICE and gasoline fueled mechanical infrastructure which certainly has plenty of casualties and human health problems all throughout the lifecycle. In fact, early on I remember reading that people used to think cars should have only so much fuel in them because they are mobile bombs in people’s homes. But the dangers come from the emissions too and when gas tankers get in accidents and leak fuel into our environment. Lithium batteries in consumer electronics are not really engineered for a ton of safety but for rapid time to market which is certainly not what I’d like to see for very long. And while shipping lithium batteries a warning label needs to be attached but shipping gasoline and lighter fluid requires special permits and must be transported isolated with certain guarantees by law. In this respect our current market has deemed lithium batteries to be far safer than gasoline without much need for regulatory pressure to do so.
- yeetaccount2 5y ago
  Makes me wonder about how Teslas will age. IIRC they have lots of small batteries placed throughout the car and I’m not sure they were designed to be replaced after wearing out.
  - db48x 5y ago
    No, Teslas do not have batteries placed throughout the car. They have a single large battery pack that bolts to the underside of the car. Inside that are smaller battery packs that contain the cells as well as the cooling channels and electrical connections. If you want to completely replace the batteries in a Tesla you can do so in less than an hour, if I recall correctly. It doesn’t require any special equipment either.
    - southerntofu 5y ago
      Does the Tesla battery come with electronic chips to prevent 3rd party batteries like inkjet printer cartridges?
      - panick21_ 5y ago
        No. But if you inject a new battery it needs to be mostly the same as the others and you need to re-balance the pack. There is software for this.
        southerntofu 5y ago
        I've never heard of balancing batteries. All i could find about it was a forum post with people just as confused as me. [0] Do you have resources on this topic? [0] https://teslamotorsclub.com/tmc/threads/balancing-the-battery.41245/ https://teslamotorsclub.com/tmc/threads/balancing-the-batter...
        panick21_ 5y ago
        This video shows how it works and from there you might find some more information: https://www.youtube.com/watch?v=T7Q0nNkQTC https://www.youtube.com/watch?v=T7Q0nNkQTC Really about 5-6 min in.
- mc32 5y ago
  If we don’t want to have micro superfund sites, are we taxing EVs via refundable deposits sufficiently to ensure toxic metals are not left around?
  - coryrc 5y ago
    GP is talking about hypothetical flow batteries, not vehicles in production.
msandford 5y ago
Stuff like that exists. They're called flow batteries. There are a few different chemistries, one on vanadium, another iron and a third on zinc bromide.
- justtemporary 5y ago
  There’s a company called Redflow in Queensland, Australia that makes zinc bromide flow batteries. [0]https://reneweconomy.com.au/redflow-in-running-to-deliver-its-first-megawatt-hour-battery-in-australia/ https://reneweconomy.com.au/redflow-in-running-to-deliver-it... [1]https://twitter.com/redflowlimited/status/1458968027827900421?s=21 https://twitter.com/redflowlimited/status/145896802782790042...
taf2 5y ago
In some sense gas is like liquid non reusable battery … the chemical reaction of mixing it at high temperature with oxygen creates a lot of energy… the other output is co2 etc… A gel in a liquid battery that deplete would presumably have some other outputs other then just pure energy since the mass of that gel is gotta go somewhere…
ZeroGravitas 5y ago
We can, but just charging when parked is better than that, and better than the old way with gas. There's no real problem left to solve, but it will keep getting better as charging tech, infrastructure, cheap renewables and EV availability expands over time.
- tpm 5y ago
  The real problem is the low energy density / high weight of the batteries (and as a result, of the whole car).
  - AnIdiotOnTheNet 5y ago
    Also battery lifetimes. I'm in the market for another used car and thought it might be nice to have an EV, but batteries are only really good for 8-10 years and replacing them can be more than the vehicle is actually worth.
    - rini17 5y ago
      This might end up as non-issue because of economies of scale. In 10 years batteries might be so cheap that making replacement packs for older cars make sense. On the other hand, there's non-negligible possibility that cars powered by ICEs will be forbidden to enter city centers in 10 years.
    - coryrc 5y ago
      Nope, they may far longer than that when temperature-controlled (so, every car but two years of Leaf cars in Arizona). The only issue is new cars are so much better than earlier ones. They continue to work just fine.
      - AnIdiotOnTheNet 5y ago
        They will still function if they have been under reasonable temperature control, but they will still undoubtedly lose capacity and therefore range. I have a 25mi commute each way and a 2012 Leaf bought today without a battery replacement seems like a pretty big gamble to me. Add to that that I live where winter weather is unkind and I am skeptical of how well old batteries would perform. From my perspective, battery technology still hasn't proven itself in this regard.
hdjjhhvvhga 5y ago
We already do liquid batteries, like for example saltwater batteries, but they're for stationary use only - too clunky to carry around.
capitainenemo 5y ago
For high density refuelable, IMO aluminium-air is your best bet. https://news.ycombinator.com/item?id=21344135 https://news.ycombinator.com/item?id=21344135
- capitainenemo 5y ago
  https://nocamels.com/2012/06/new-cleantech-co-to-power-cars-with-aluminum-grains/ https://nocamels.com/2012/06/new-cleantech-co-to-power-cars-... An example of a pourable variant.
GistNoesis 5y ago
If you accept low efficiency, you can use thermal machines (max efficiency of roughly 35%), you can DIY such liquid battery : molten wax and a Stirling engine. Melt the wax to charge, and store in a thermos. You can use heat pumps to increase the efficiency by recovering wasted heat. Plenty of things are technologically possible but as energy storage is commoditized so outside the lab we only care for the best ones where cost, efficiency, energy density, power density, energy leakage and battery life define the Pareto frontier. There are flow batteries where you can switch the electrolytes when they are discharged. You can also use standard lead-acid gel battery and switch them when they are discharged. (Use multiple small batteries and discharge them sequentially). You can also switch solid-state Li-ion batteries. There are also some molten metal and salts batteries : for example Ambri (https://ambri.com/technology/ https://ambri.com/technology/) (https://www.youtube.com/watch?v=m8751tkBU_Q https://www.youtube.com/watch?v=m8751tkBU_Q) make some liquid metal battery ( where the discharged state is an alloy, and charging the battery separate back to its original components. Their batteries work at 500°C and are 80% efficient (vs lithium 95% efficient), and need to be immobile when used, but other can work at room temperature.

Why can't we make liquid batteries yet, so you can tank "gel", discard the old gel through the bottom of the car at the "gas" station.

by tiku 5y ago

Why can't we make liquid batteries yet, so you can tank "gel", discard the old gel through the bottom of the car at the "gas" station.

kumarvvr 5y ago

Power to weight ratio, in such systems, is very low, at current technologies.

api 5y ago

We can but my understanding is that there are issues, one of them being that these compounds are horrible things that you don’t want spilling or getting on people. Any car tech has to pass what I call the “rusty pickup test.” It has to degrade gracefully and remain useful and safe enough for use. Current EV tech passes that. I can totally picture a rusty old F-150 Lightning with aftermarket repairs.

southerntofu 5y ago
> remain useful and safe enough for use. Current EV tech passes that. Does it though? I heard exploding/self-burning batteries, which were a problem with some cellphones, were a much bigger problems with electric vehicles? I don't have data on how often it happens though, but that makes me skeptical.
- api 5y ago
  Gasoline fires happen all the time. They just don't make the news because they're not new. Like EV battery fires they are statistically rare. We got pretty good at handling incredibly toxic and flammable liquid fuels on a routine basis and we can do this for high energy density batteries too.
- devonkim 5y ago
  It’s worth considering the status quo of ICE and gasoline fueled mechanical infrastructure which certainly has plenty of casualties and human health problems all throughout the lifecycle. In fact, early on I remember reading that people used to think cars should have only so much fuel in them because they are mobile bombs in people’s homes. But the dangers come from the emissions too and when gas tankers get in accidents and leak fuel into our environment. Lithium batteries in consumer electronics are not really engineered for a ton of safety but for rapid time to market which is certainly not what I’d like to see for very long. And while shipping lithium batteries a warning label needs to be attached but shipping gasoline and lighter fluid requires special permits and must be transported isolated with certain guarantees by law. In this respect our current market has deemed lithium batteries to be far safer than gasoline without much need for regulatory pressure to do so.
yeetaccount2 5y ago
Makes me wonder about how Teslas will age. IIRC they have lots of small batteries placed throughout the car and I’m not sure they were designed to be replaced after wearing out.
- db48x 5y ago
  No, Teslas do not have batteries placed throughout the car. They have a single large battery pack that bolts to the underside of the car. Inside that are smaller battery packs that contain the cells as well as the cooling channels and electrical connections. If you want to completely replace the batteries in a Tesla you can do so in less than an hour, if I recall correctly. It doesn’t require any special equipment either.
  - southerntofu 5y ago
    Does the Tesla battery come with electronic chips to prevent 3rd party batteries like inkjet printer cartridges?
    - panick21_ 5y ago
      No. But if you inject a new battery it needs to be mostly the same as the others and you need to re-balance the pack. There is software for this.
      - southerntofu 5y ago
        I've never heard of balancing batteries. All i could find about it was a forum post with people just as confused as me. [0] Do you have resources on this topic? [0] https://teslamotorsclub.com/tmc/threads/balancing-the-battery.41245/ https://teslamotorsclub.com/tmc/threads/balancing-the-batter...
        panick21_ 5y ago
        This video shows how it works and from there you might find some more information: https://www.youtube.com/watch?v=T7Q0nNkQTC https://www.youtube.com/watch?v=T7Q0nNkQTC Really about 5-6 min in.
mc32 5y ago
If we don’t want to have micro superfund sites, are we taxing EVs via refundable deposits sufficiently to ensure toxic metals are not left around?
- coryrc 5y ago
  GP is talking about hypothetical flow batteries, not vehicles in production.

msandford 5y ago

Stuff like that exists. They're called flow batteries. There are a few different chemistries, one on vanadium, another iron and a third on zinc bromide.

justtemporary 5y ago
There’s a company called Redflow in Queensland, Australia that makes zinc bromide flow batteries. [0]https://reneweconomy.com.au/redflow-in-running-to-deliver-its-first-megawatt-hour-battery-in-australia/ https://reneweconomy.com.au/redflow-in-running-to-deliver-it... [1]https://twitter.com/redflowlimited/status/1458968027827900421?s=21 https://twitter.com/redflowlimited/status/145896802782790042...

taf2 5y ago

In some sense gas is like liquid non reusable battery … the chemical reaction of mixing it at high temperature with oxygen creates a lot of energy… the other output is co2 etc… A gel in a liquid battery that deplete would presumably have some other outputs other then just pure energy since the mass of that gel is gotta go somewhere…

ZeroGravitas 5y ago

We can, but just charging when parked is better than that, and better than the old way with gas. There's no real problem left to solve, but it will keep getting better as charging tech, infrastructure, cheap renewables and EV availability expands over time.

tpm 5y ago
The real problem is the low energy density / high weight of the batteries (and as a result, of the whole car).
- AnIdiotOnTheNet 5y ago
  Also battery lifetimes. I'm in the market for another used car and thought it might be nice to have an EV, but batteries are only really good for 8-10 years and replacing them can be more than the vehicle is actually worth.
  - rini17 5y ago
    This might end up as non-issue because of economies of scale. In 10 years batteries might be so cheap that making replacement packs for older cars make sense. On the other hand, there's non-negligible possibility that cars powered by ICEs will be forbidden to enter city centers in 10 years.
  - coryrc 5y ago
    Nope, they may far longer than that when temperature-controlled (so, every car but two years of Leaf cars in Arizona). The only issue is new cars are so much better than earlier ones. They continue to work just fine.
    - AnIdiotOnTheNet 5y ago
      They will still function if they have been under reasonable temperature control, but they will still undoubtedly lose capacity and therefore range. I have a 25mi commute each way and a 2012 Leaf bought today without a battery replacement seems like a pretty big gamble to me. Add to that that I live where winter weather is unkind and I am skeptical of how well old batteries would perform. From my perspective, battery technology still hasn't proven itself in this regard.

hdjjhhvvhga 5y ago

We already do liquid batteries, like for example saltwater batteries, but they're for stationary use only - too clunky to carry around.

capitainenemo 5y ago

For high density refuelable, IMO aluminium-air is your best bet. https://news.ycombinator.com/item?id=21344135 https://news.ycombinator.com/item?id=21344135

capitainenemo 5y ago
https://nocamels.com/2012/06/new-cleantech-co-to-power-cars-with-aluminum-grains/ https://nocamels.com/2012/06/new-cleantech-co-to-power-cars-... An example of a pourable variant.

GistNoesis 5y ago

If you accept low efficiency, you can use thermal machines (max efficiency of roughly 35%), you can DIY such liquid battery : molten wax and a Stirling engine. Melt the wax to charge, and store in a thermos. You can use heat pumps to increase the efficiency by recovering wasted heat. Plenty of things are technologically possible but as energy storage is commoditized so outside the lab we only care for the best ones where cost, efficiency, energy density, power density, energy leakage and battery life define the Pareto frontier. There are flow batteries where you can switch the electrolytes when they are discharged. You can also use standard lead-acid gel battery and switch them when they are discharged. (Use multiple small batteries and discharge them sequentially). You can also switch solid-state Li-ion batteries. There are also some molten metal and salts batteries : for example Ambri (https://ambri.com/technology/ https://ambri.com/technology/) (https://www.youtube.com/watch?v=m8751tkBU_Q https://www.youtube.com/watch?v=m8751tkBU_Q) make some liquid metal battery ( where the discharged state is an alloy, and charging the battery separate back to its original components. Their batteries work at 500°C and are 80% efficient (vs lithium 95% efficient), and need to be immobile when used, but other can work at room temperature.