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Given that sodium ion is claimed to - charge twice as fast as lithium ion - have double the number of charge cycles - cost substantially less - be substanti

by tromp 4y ago

Given that sodium ion is claimed to - charge twice as fast as lithium ion - have double the number of charge cycles - cost substantially less - be substantially safer - and more environmentally friendly I think it would be the clear preference for all but the highest performance vehicles. Note that Tesla is also trying to reduce cost in moving to 4680 cells [1]: > the main reason Tesla is using 4680 batteries at the moment is to cut manufacturing costs, rather than any of the other pie-in-the-sky advantages announced on Battery Day a few years back. > A Model Y's 4680 pack, for instance, is US$3,600 cheaper to manufacture than one with 2170 cells, but even then Tesla is only halfway through with the cost reduction potential of the new technology. It has yet to master and scale the dry-coating cathode method which would bring the pack's cost down US$5,500 compared to the 2170 battery. [1] https://www.notebookcheck.net/Tesla-4680-vs-2170-battery-cell-test-reveals-lower-energy-density-in-the-Texas-made-Model-Y.669162.0.html#:~:text=The%20analysis%20returned%20244%20Wh,vehicles%20here%20in%20the%20US https://www.notebookcheck.net/Tesla-4680-vs-2170-battery-cel....

quonn 4y ago
Comparing to LFP the advantages are not that big. It might be cheaper and scale better. Charging speed is now mostly limited by public charger speed and good enough. I expect sodium batteries to have a big impact in cars that cost 25k or less.
- tromp 4y ago
  Taking out the lithium seems a rather big advantage. Anyway, it's good to have two promising alternatives to Li-ion, both of which are clearly superior for home use, and likely for affordable, smaller range EVs as well.
- adrian_b 4y ago
  The only significant advantage compared to LFP appears to be the price. However the price advantage is more than enough. After a short googling, it appears that I could buy right now a battery large enough to supply the energy for one day for my house (5 kWh), either as sodium-ion for $650 or as lithium-iron phosphate for $5000 (with very similar specifications for endurance and size). The former I could buy at any time, for the latter I would have to save money for some months to be able to afford it. That is a large enough advantage.
  - quonn 4y ago
    Yeah, I'm talking about car batteries.
  - scythe 4y ago
    That LFP price can't be right. That's $1000/kWh! Batteries have been cheaper than that for at least half a decade. And I'm pretty sure Na-ion (at room temperature) hasn't even hit the market yet! Googling "sodium-ion battery price" just gave me textbooks.
    - adrian_b 4y ago
      I believe that there might be cheaper LFP, that is why I have written "after a short googling". $1000 per kWh was the first price that I have found for a 5 kWh LFP battery and I am lazy now to search for a cheaper one, so this is a real price, even if it is likely not the best price. For a much larger battery, a quick search shows EUR 20000 for 50 kWh, i.e. EUR 400/kWh (though this price is older and now it might have increased). It is normal for the price per kWh to decrease at very large capacities. Also, the fact that LFP were cheaper than this a decade ago is irrelevant, because googling about their price finds that "lithium prices have surged over 700% since the start of 2021, which has led to a big jump in battery pack prices" (written in May 2022). However, Na-ion batteries for solar energy storage have certainly already hit the market, e.g.: https://www.alibaba.com/product-detail/SUNPOK-48V-5kwh-Sodium-ion-battery_1600550915863.html https://www.alibaba.com/product-detail/SUNPOK-48V-5kwh-Sodiu... EDIT: After an extra search, I have seen an offer for a LFP 5 kWh battery @ $2000, so it looks like the $400/kWh price is available for lower capacities too. Nevertheless, this price is less reliable than the higher prices seen initially, because it is only for some kind of pre-order with unknown delivery time.
      - guerby 4y ago
        5 kWh LFP battery with BMS and user serviçable rack format from a reputable brand in the USA is $1,649.99 so $330/kWh, see here for example: https://www.currentconnected.com/product/sk48v100/ https://www.currentconnected.com/product/sk48v100/ You can easily find other brands for less than $300/kWh, and plenty of review/teardowns on youtube. Edit: adding "Typical capacity at 80% DOD @.5C Rate is over 7000 Cycles" so if you bring your battery to 7000 80% cycles at 0.5C you got 28000 kWh out of it, so 0.059 USD/kWh out of the battery (and you still have 4 kWh usable in the battery so many more cycles).
- zeristor 4y ago
  There are some larger charging stations with large battery banks that can store enough electricity for fast charging.
  - quonn 4y ago
    It's more about being able to deliver it when many cars are charging. Charging speeds go down considerably. I typically don't get the maximum possible speed and often am far off and sometimes that depends on the number of cars charging.
    - chris222 4y ago
      Your actual limitation when the site is full is usually the utility transformer. Tesla have been installing many 8 stall and even 12 stall sites with 750kVA pad transformers. If they had a Tesla Megapack as a buffer for example the transformer wouldn’t be the bottleneck as the output is greater from the Megapack.
- tuatoru 4y ago
  > cars that cost 25k or less In other words, most cars. "Americans remain resistant to the lure of EVs, which are still unaffordable": https://arstechnica.com/cars/2022/11/only-1-in-3-americans-would-prefer-an-electric-vehicle-survey-finds/ https://arstechnica.com/cars/2022/11/only-1-in-3-americans-w...
- _ea1k 4y ago
  > Charging speed is now mostly limited by public charger speed and good enough. Not sure where this is the case. Here, the 250kw chargers are plentiful, but cars average closer to 120kw because of the charge curve. We're still battery limited most of the time.
  - quonn 4y ago
    At most Tesla chargers in Europe when they are full.
throwawaymaths 4y ago
The assumption there is that lithium is fully optimized. It's not.
- cogman10 4y ago
  Granted, but lithium has also had a significant amount of additional R&D, particularly in manufacturing. Time will tell if sodium batteries can be competitive, I don't know that it's clear yet.
  - throwawaymaths 4y ago
    Lithium and sodium are similar enough that it's hard to imagine that some of the learnings from lithium haven't translated to sodium.
jetanoia 4y ago
Those 5 advantages are very important, but you haven’t mentioned its disadvantages which render the advantages less dramatic. A significant disadvantage is the lower energy density of the sodium battery chemistry. Implications include faster discharge/lower range if the physical dimensions are the same as a lithium battery, or if optimized for more range/power, then it would be a larger and heavier pack vs lithium with the costs that entails. This lower energy density is one of the main reasons it has been considered more suited to stationary application because the extra space and weight is less problematic than in a mobile applicaiton

by tromp 4y ago

quonn 4y ago

Comparing to LFP the advantages are not that big. It might be cheaper and scale better. Charging speed is now mostly limited by public charger speed and good enough. I expect sodium batteries to have a big impact in cars that cost 25k or less.

tromp 4y ago
Taking out the lithium seems a rather big advantage. Anyway, it's good to have two promising alternatives to Li-ion, both of which are clearly superior for home use, and likely for affordable, smaller range EVs as well.
adrian_b 4y ago
The only significant advantage compared to LFP appears to be the price. However the price advantage is more than enough. After a short googling, it appears that I could buy right now a battery large enough to supply the energy for one day for my house (5 kWh), either as sodium-ion for $650 or as lithium-iron phosphate for $5000 (with very similar specifications for endurance and size). The former I could buy at any time, for the latter I would have to save money for some months to be able to afford it. That is a large enough advantage.
- quonn 4y ago
  Yeah, I'm talking about car batteries.
- scythe 4y ago
  That LFP price can't be right. That's $1000/kWh! Batteries have been cheaper than that for at least half a decade. And I'm pretty sure Na-ion (at room temperature) hasn't even hit the market yet! Googling "sodium-ion battery price" just gave me textbooks.
  - adrian_b 4y ago
    I believe that there might be cheaper LFP, that is why I have written "after a short googling". $1000 per kWh was the first price that I have found for a 5 kWh LFP battery and I am lazy now to search for a cheaper one, so this is a real price, even if it is likely not the best price. For a much larger battery, a quick search shows EUR 20000 for 50 kWh, i.e. EUR 400/kWh (though this price is older and now it might have increased). It is normal for the price per kWh to decrease at very large capacities. Also, the fact that LFP were cheaper than this a decade ago is irrelevant, because googling about their price finds that "lithium prices have surged over 700% since the start of 2021, which has led to a big jump in battery pack prices" (written in May 2022). However, Na-ion batteries for solar energy storage have certainly already hit the market, e.g.: https://www.alibaba.com/product-detail/SUNPOK-48V-5kwh-Sodium-ion-battery_1600550915863.html https://www.alibaba.com/product-detail/SUNPOK-48V-5kwh-Sodiu... EDIT: After an extra search, I have seen an offer for a LFP 5 kWh battery @ $2000, so it looks like the $400/kWh price is available for lower capacities too. Nevertheless, this price is less reliable than the higher prices seen initially, because it is only for some kind of pre-order with unknown delivery time.
    - guerby 4y ago
      5 kWh LFP battery with BMS and user serviçable rack format from a reputable brand in the USA is $1,649.99 so $330/kWh, see here for example: https://www.currentconnected.com/product/sk48v100/ https://www.currentconnected.com/product/sk48v100/ You can easily find other brands for less than $300/kWh, and plenty of review/teardowns on youtube. Edit: adding "Typical capacity at 80% DOD @.5C Rate is over 7000 Cycles" so if you bring your battery to 7000 80% cycles at 0.5C you got 28000 kWh out of it, so 0.059 USD/kWh out of the battery (and you still have 4 kWh usable in the battery so many more cycles).
zeristor 4y ago
There are some larger charging stations with large battery banks that can store enough electricity for fast charging.
- quonn 4y ago
  It's more about being able to deliver it when many cars are charging. Charging speeds go down considerably. I typically don't get the maximum possible speed and often am far off and sometimes that depends on the number of cars charging.
  - chris222 4y ago
    Your actual limitation when the site is full is usually the utility transformer. Tesla have been installing many 8 stall and even 12 stall sites with 750kVA pad transformers. If they had a Tesla Megapack as a buffer for example the transformer wouldn’t be the bottleneck as the output is greater from the Megapack.
tuatoru 4y ago
> cars that cost 25k or less In other words, most cars. "Americans remain resistant to the lure of EVs, which are still unaffordable": https://arstechnica.com/cars/2022/11/only-1-in-3-americans-would-prefer-an-electric-vehicle-survey-finds/ https://arstechnica.com/cars/2022/11/only-1-in-3-americans-w...
_ea1k 4y ago
> Charging speed is now mostly limited by public charger speed and good enough. Not sure where this is the case. Here, the 250kw chargers are plentiful, but cars average closer to 120kw because of the charge curve. We're still battery limited most of the time.
- quonn 4y ago
  At most Tesla chargers in Europe when they are full.

throwawaymaths 4y ago

The assumption there is that lithium is fully optimized. It's not.

cogman10 4y ago
Granted, but lithium has also had a significant amount of additional R&D, particularly in manufacturing. Time will tell if sodium batteries can be competitive, I don't know that it's clear yet.
- throwawaymaths 4y ago
  Lithium and sodium are similar enough that it's hard to imagine that some of the learnings from lithium haven't translated to sodium.

jetanoia 4y ago

Those 5 advantages are very important, but you haven’t mentioned its disadvantages which render the advantages less dramatic. A significant disadvantage is the lower energy density of the sodium battery chemistry. Implications include faster discharge/lower range if the physical dimensions are the same as a lithium battery, or if optimized for more range/power, then it would be a larger and heavier pack vs lithium with the costs that entails. This lower energy density is one of the main reasons it has been considered more suited to stationary application because the extra space and weight is less problematic than in a mobile applicaiton