How much does a battery weigh that can store a million joules of energy?
jim m asked:
If a good energy storage system was available electric cars would be a lot more useful. Batteries do store energy so how much do they weigh per megajoule of storage?
If a good energy storage system was available electric cars would be a lot more useful. Batteries do store energy so how much do they weigh per megajoule of storage?
That is probably heavily dependent on the type of battery and how that certain type of battery was constructed. Mastermind
joules= mass + weight Kristen T
Lithium Thionol Chloride battery: 2.5MJ/kg.
So that is 400g or slightly less than a lbs.
Rechargeable:
Lithium Ion battery: 0.5-0.7MJ/kg
You would need about 2kg of battery mass for that.
Please keep in mind that it is not practical to fully deplete Li-Ion batteries. More than 50-60% depletion and the cells die much more quickly. So in reality you can, at best, get 0.3MJ/kg or so.
And sadly, an electric car won’t drive for long on a MJ. Three, four minutes on the highway, at most. Which is why you need approx. 200-500kg battery packs with current technology to make a practical electric car. amansscientiae
It all depends of the type of battery.
Lead/acid batteries that are found in cars have the worst weight rating.
Some batteries have better power/weight ratios.
Some batteries have better Density/power ratios.
Some batteries blow-up if you short them out or poke a hole in them!
Check out my link on this weeks article on batteries mixmaster2
a big Layden jar ?
0.5CV^2
or 1Amp for 1sec gives 1 volt to_700million_idiots