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I’ve been hearing about these for a few years now. Huge if they work out at a large scale.
I’ve been hearing about these for a few years now. Huge if they work out at a large scale.
According to Wikipedia:
Looks like power to weight it much higher, while energy per volume and energy per mass is comparable to existing lithium ion batteries.
No, the energy to volume is much less.
See, that’s what I thought, but the wiki article seems to disagree.
Or am I just misreading something?
idk about that, the regularly cited reason Na-ion batteries are mainly being looked at for grid storage rather than vehicle applications is their bad Wh/l and W/kg numbers compared to Li-ion. the table in the Na-ion article seems to use “1000W/kg” without a source, and it shows lithium as being about a third of that even though the Li-ion article quotes figures up to 10kW/kg.
seems the editors of the two articles aren’t cross-checking eachother.
The “1000W/kg” figure appears to be from Wikipedia, which claims https://www.idtechex.com/en/research-article/sodium-ion-batteries-will-diversify-the-energy-storage-industry/30405 as a source. Wikipedia has the information in a table flagged as “Needs update”.
Anyway, most of the lithium-ion chemistry variations drop off relatively fast in capacity over repeated charge cycles (the exception being LiFePo4). If the sodium-ion chemistry is better that way, and drops off less in the cold, it’s still worth exploring for vehicle use even if the energy density is a little lower.
In colder climates, the lower density could be offset by better performance in cold. This is why sodium has made it to large mining trucks.
from other comments it seems the energy density of batteries currently on the market is about 2/3rds that of lithium cells.
there’s also the asymmetry to worry about: with a max discharge rate of 8C but a charge rate of 3C there could potentially be limits on regen braking. if i’m understanding it correctly, sodium cells degrade quickly at higher charge rates.
Interesting, but from what I understand limited charging would only be a problem if you do not have large enough battery capacity. So for heavier vehicles with larger capacity this might not matter much.
PS: This video about the CATL NaFePO4 battery also mentions a “half sodium half lithium” battery pack for cars to combine the best of both.
Just put condensers/a small lithium break battery in.
i think bmw was working on something like that.
Googling says 175 whr/kg for catls sodium car battery that’s already in production cars vs 270 whr/kg for Tesla’s lithium.
Probably numbers for the raw cell though, not the balancing and cooling which could make sodium a bit more competitive.
W/kilo? Isn’t there a h missing or something?
one is energy density, the other is power density.
Aah, makes sense. I have seen soo many people confounding power and energy I thought it was the same here, my excuses.
No, it seems like you have zero idea what you are talking about and are confusing W/kg with Wh/kg, which are very different metrics