Lauren asked in Science & MathematicsPhysics · 3 years ago

# Compare the energy in a pound of gasoline to the energy in a pound of a modern computer battery:?

( ) The gasoline has about the same energy as the battery

( ) The battery has 10x more energy

( ) The gasoline has 10x more energy

( ) The gasoline has 100x more energy

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• 3 years ago

The best LI-ion batterys today have about 265 Watt-hours of energy per kilogram of weight for the best rechargeable units.

Gasoline contains about 12,889 Watt-hours of energy per kilogram of weight.

This is nabout 48.6 times as much energy available in a kilogram of gasoline versus what is available in a kilogram of Li battery.

Multiply these numbers by 2.2 to convert to pounds but the differential is the same.

So, I would use answer 100X since is the closest I see since it is off by a factor of 2 and the other answers are off by about 5 times.

Last, although the gasoline is gone when used up, a rechargeable LI battery is only good for a minimum number of recycles before it must be replaced.

Overall efficiency of the gasoline in a car may be reduced to about 4000 watt-hours of deliverable energy (depending on which report you read) this is still 15 times more energy per kg than a battery. The Li battery while seeming to be the perfect coupling with the electric vehicle has a CO2 foot print which is abou 25%

of a gasoline power car. This takes into account the energy to charge the battery comes from fossil fueled power plants that operate at about 33% efficiency. Also the batteries have a limited number of charge cycles before they have to be replaced.

I ignore the costs of the rare metals needed make the magnets and electronics for the electric car.

Hope this helps,

Newton1Law

• 3 years ago

That would depend on whether you discharge the battery or burn it.

Seriously, though, that comparison doesn't make sense. If you want to use it for transportation, you'd have to contemplate the full system - and that would depend on where you want to put the boundaries. Does creating the charge for the battery or the fuel also count?

• 3 years ago

I would guess gas has 10x more energy per pound.

However, how do you take into account that an electric drive is 5 times more efficient than a gas engine?

And the battery is not consumed and reusable, whereas the gasoline is gone?