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.
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.
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.
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.
Just put condensers/a small lithium break battery in.
i think bmw was working on something like that.