4 ms·
That's maybe a bit pessimistic. We have come a long way (NiCd 40-60 Wh/kg, NiMH 30-80 Wh/kg, LiIon 150-250 Wh/kg), we're just still a long way from fossil fuels
by tonyarkles 13y ago
That's maybe a bit pessimistic. We have come a long way (NiCd 40-60 Wh/kg, NiMH 30-80 Wh/kg, LiIon 150-250 Wh/kg), we're just still a long way from fossil fuels (~12,000 Wh/kg for gasoline). I think the biggest trick is to set expectations properly and wait it out as battery technology continues to evolve.
http://en.wikipedia.org/wiki/Energy_density http://en.wikipedia.org/wiki/Energy_density
http://en.wikipedia.org/wiki/Rechargeable_battery http://en.wikipedia.org/wiki/Rechargeable_battery
- chongli 13y agoWoah, you can't compare those numbers directly. If you could then Tesla cars would be travelling just 10s of miles per charge. Obviously, there are many other factors: weight and bulk of the power train, power train efficiency, regenerative breaking, driving conditions, etc.
- tonyarkles 13y agoOh, totally agree! I wasn't necessarily referring to electric cars specifically, more just comparing how much energy different things store, although it does highlight why building long-range and high-performance electric cars is a Hard Problem. There's a lot of things that are different. The 50L of fuel in my car is going to weigh about 45kg and will get me about 800km, and the batteries in a Tesla weigh 300-500kg (not sure exactly, found a few different numbers). But like you say, the power train is considerably different, etc etc.
- kyrra 13y agoPoking around, on the Lithium-air battery wiki page, they have this quote: > The energy density of gasoline is approximately 13 kW·h/kg, which corresponds to 1.7 kW·h/kg of energy provided to the wheels after losses. Any clue what the energy provided to the wheels is for electric cars like a Tesla? I'm wonder what the energy loss is for electric cars from stored form to actual power at the wheel.
- plorkyeran 13y agoThe Tesla Roadster was 88% efficient. I don't remember the exact value for the Model S, but it's in the same general range. This huge difference is the main thing that makes electric cars viable.
- Zoomla 13y agoAlso, electric cars can be powered by coal, nuclear, hydroelectric, etc... or whatever the grid is powered by.
- seanalltogether 13y agoGood electric motors typically have 90%-95% efficiency. However tesla is using AC motors driven by DC batteries, so they have to convert.