3 ms·

For comparison gasoline has about 9000 Wh/L of raw chemical energy, of which maybe 30-40% gets converted to useful work.

culopatin 10mo ago
Almost half way there
jeffbee 10mo ago
ICE engines outsource half of the reactants to the atmosphere, so this comparison isn't as useful as it appears at first.
- MobiusHorizons 10mo ago
  Batteries can make use of the atmosphere as well (eg aluminum air batteries/ or venting hydrogen in lead acid batteries) although I don’t know of any rechargeable chemistries off hand that use environmental oxygen. All that to say the trick is available for batteries even if the best current chemistries by mass density don’t make use of it.
  - scott113341 10mo ago
    One I'm familiar with (but don't know deeply about) is Iron-air batteries [1]. Form Energy [2], an interesting grid-storage startup uses them. They're not energy-dense whatsoever, but very cheap, which makes them economical for that application. [1]: https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemical_cell https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemi... [2]: https://formenergy.com/technology/battery-technology/ https://formenergy.com/technology/battery-technology/
thesz 10mo ago
https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density Gunpowder is 4-10 times less energy dense than gasoline. The difference is that gunpowder includes fuel and oxygen-producing substances, much like most of Li-ion batteries. This thing is in gunpowder energy density range.
Yaggo 10mo ago
30…40% is very ideal number, 15…25% is often the reality.
- kingstnap 10mo ago
  A good hybrid can do very well. Presumably by keeping the engine in exactly its sweet spot and designing aggressively for that. BYD for example claims 46% thermal efficiency. [0] [0] https://ev.com/news/byd-hybrid-efficiency https://ev.com/news/byd-hybrid-efficiency
  - Yaggo 10mo ago
    Yes, hybrids are much more efficient especially in city driving, not so much on highway. I used to drive a Prius back in the day.

culopatin 10mo ago

Almost half way there

jeffbee 10mo ago

ICE engines outsource half of the reactants to the atmosphere, so this comparison isn't as useful as it appears at first.

MobiusHorizons 10mo ago
Batteries can make use of the atmosphere as well (eg aluminum air batteries/ or venting hydrogen in lead acid batteries) although I don’t know of any rechargeable chemistries off hand that use environmental oxygen. All that to say the trick is available for batteries even if the best current chemistries by mass density don’t make use of it.
- scott113341 10mo ago
  One I'm familiar with (but don't know deeply about) is Iron-air batteries [1]. Form Energy [2], an interesting grid-storage startup uses them. They're not energy-dense whatsoever, but very cheap, which makes them economical for that application. [1]: https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemical_cell https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemi... [2]: https://formenergy.com/technology/battery-technology/ https://formenergy.com/technology/battery-technology/

thesz 10mo ago

https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density Gunpowder is 4-10 times less energy dense than gasoline. The difference is that gunpowder includes fuel and oxygen-producing substances, much like most of Li-ion batteries. This thing is in gunpowder energy density range.

Yaggo 10mo ago

30…40% is very ideal number, 15…25% is often the reality.

kingstnap 10mo ago
A good hybrid can do very well. Presumably by keeping the engine in exactly its sweet spot and designing aggressively for that. BYD for example claims 46% thermal efficiency. [0] [0] https://ev.com/news/byd-hybrid-efficiency https://ev.com/news/byd-hybrid-efficiency
- Yaggo 10mo ago
  Yes, hybrids are much more efficient especially in city driving, not so much on highway. I used to drive a Prius back in the day.