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Posted by7 months ago

https://spectrum.ieee.org/ev-battery-2658649740

Why this is misinformation: the article simply takes the nameplate watt-hours per liter of different fuel types. It compares recent lithium ion batteries, with an energy density of 750 Wh/L , to gasoline with 9,600.

This appears correct but it's bullshit.

Reasons: it's irrelevant how much heat energy gasoline has because thermodynamics prevents you from converting all of that energy into lower entropy work. Electrical energy stored has lower entropy and can be converted to work (movement of the car or pumping heat, etc) with far greater efficiency.

If we take the top end efficiency for an ICE drivetrain at 27% and compare it to batteries at 95%, the numbers above become:

9600* 0.27 = 2592 vs 7500*.95 = 710. So this would indicate that gasoline is 3.65 times as much volumetrically dense as batteries in the real world.

Now we have to factor in that issue that while electrical energy can be converted to work with a tiny motor and motor controller, a gas engine needs: the engine, fuel vapor control system, exhaust and muffler, a larger radiator, the transmission with gears or CVT, and of course the engine itself.

You have another issue that usable volume in a vehicle is also better with batteries because they can be crammed into almost any shape, while the above gas engine parts have a non-negotiable bulky shape for all commercial engine designs that are cheap and reliable.

I'm not sure how to account for this other than to say it probably evens up all of the difference and battery vehicles have as much or more usable volume for the same outer dimensions as a gas vehicle with similar range.

Main problem is weight (batteries are heavy), charging speed (gas is faster), and cost of the batteries.

The article in reality I think is just misinformation.

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