4 ms·

They say the charge capacity is 1017 mAh/g. That is about four times the value of a typical (good!) Li-Ion battery.

by deng 4y ago

bjarneh 4y ago
Isn't that quite close to the magic number which makes electric planes a viable option? 1 kW = 1 kg; Musk said something about that in a podcast I think...
- termain 4y ago
  That's specific power, not specific energy. Do you mean 1 kW*r/kg?
  - bjarneh 4y ago
    Yes of course, I meant to say 1 kW·h = 1 kg; but I'm not certain if I remember correctly now; I could be off by a factor of 10 I guess. It was either 1 kg battery weight = 1 kW·h, or perhaps he said 10 kW·h had to be contained in a 1 kg battery to allow all types of air travel. I think the 100 kW·h Tesla batteries found in the Model S/X weigh around 750 kg; so I guess electric air travel is still difficult unless a battery breakthrough happens; at least in terms of weight.
danw1979 4y ago
... assuming the cell voltage is the same ? A quick google suggests Na-S cells at high temperatures are ~2.1V nominal (as opposed to 3.2V for LFP), but I lack the physics chops to parse the paper in the article to validate this. Anyway this sounds like a tiny experimental cell and for real world applications you'd want to see the Wh/kg for a fully packaged product.
- deng 4y ago
  > for real world applications you'd want to see the Wh/kg for a fully packaged product Oh, absolutely, there's still a lot of stuff that could prohibit this technology from ever becoming an actual product. AFAICS, they also don't say anything about dependence an ambient temperature, for instance. It might be that this thing disintegrates as soon as it's freezing. Or, actually the most likely: that it's simply not possible to build this thing at scale with reasonable cost.
dev_tty01 4y ago
Not useful without the cell voltage. Need both to figure out the energy storage. Anyone?
- mikeyouse 4y ago
  Cell degradation was tested at 1V - so conveniently right around 1,000wh/kg.
Robotbeat 4y ago
Is that for a complete cell or just an electrode? If it's not specified, you can bet it's just for the electrode. Complete cell is what matters (or to be strictly true, a full battery... but that's another story). Plus the voltage difference... IIRC, Na-S is 2.1V compared to 3.7V nominal for Lithium-ion, high voltage versions sometimes up to 4.35V max voltage. Perhaps a factor of 2 difference in voltage, plus it's only counting a portion of the cell mass.

They say the charge capacity is 1017 mAh/g. That is about four times the value of a typical (good!) Li-Ion battery.

by deng 4y ago

They say the charge capacity is 1017 mAh/g. That is about four times the value of a typical (good!) Li-Ion battery.

Isn't that quite close to the magic number which makes electric planes a viable option? 1 kW = 1 kg; Musk said something about that in a podcast I think...

termain 4y ago
That's specific power, not specific energy. Do you mean 1 kW*r/kg?
- bjarneh 4y ago
  Yes of course, I meant to say 1 kW·h = 1 kg; but I'm not certain if I remember correctly now; I could be off by a factor of 10 I guess. It was either 1 kg battery weight = 1 kW·h, or perhaps he said 10 kW·h had to be contained in a 1 kg battery to allow all types of air travel. I think the 100 kW·h Tesla batteries found in the Model S/X weigh around 750 kg; so I guess electric air travel is still difficult unless a battery breakthrough happens; at least in terms of weight.

danw1979 4y ago

... assuming the cell voltage is the same ? A quick google suggests Na-S cells at high temperatures are ~2.1V nominal (as opposed to 3.2V for LFP), but I lack the physics chops to parse the paper in the article to validate this. Anyway this sounds like a tiny experimental cell and for real world applications you'd want to see the Wh/kg for a fully packaged product.

deng 4y ago
> for real world applications you'd want to see the Wh/kg for a fully packaged product Oh, absolutely, there's still a lot of stuff that could prohibit this technology from ever becoming an actual product. AFAICS, they also don't say anything about dependence an ambient temperature, for instance. It might be that this thing disintegrates as soon as it's freezing. Or, actually the most likely: that it's simply not possible to build this thing at scale with reasonable cost.

dev_tty01 4y ago

Not useful without the cell voltage. Need both to figure out the energy storage. Anyone?

mikeyouse 4y ago
Cell degradation was tested at 1V - so conveniently right around 1,000wh/kg.

Robotbeat 4y ago

Is that for a complete cell or just an electrode? If it's not specified, you can bet it's just for the electrode. Complete cell is what matters (or to be strictly true, a full battery... but that's another story). Plus the voltage difference... IIRC, Na-S is 2.1V compared to 3.7V nominal for Lithium-ion, high voltage versions sometimes up to 4.35V max voltage. Perhaps a factor of 2 difference in voltage, plus it's only counting a portion of the cell mass.