An ICE hybrid is a gas car with a little electric motor shoehorned inside.
A "plug in" hybrid as they are called is a full electric drivetrain, with a gas generator like you'd buy at Lowes stuck in the boot
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It seems trivial, but the difference is massive. The former is super complicated, heavy, and expensive, as you need all the junk a gas car needs and the electric stuff to go with it.
The later is hilarously efficient. It takes the best part of electric cars, the dead simple drive train, and solves their achilles heel: the massive battery. You can get away with a dirt cheap 3 horsepower generator in such a setup and shrink the battery massively, whereas a ICE hybrid needs a huge car engine and (like I said) all the expensive junk that goes with it.
You don't see more of the later because:
Car manufacturers are geared to produce ICE cars, and reserve the electric drivetrain capacitry for profitable luxury vehicles first.
This is just speculation on my part, but a gas range extending generator "taints" a full electric car, making it unpalatable to people who think it ruins the image, eco friendliness or whatever, when it's actually better for the environment because the battery isn't so freaking big.
Another point I was getting as is that pure electric cars suffer from the same problem space rockets do: most of their weight is fuel.
Hence they are heavy, need a lot of raw material and manufacturing. Read: Expensive and bad for the environment, compared to a cheaper plug in hybrid.
And a tiny, 5 horsepower gasoline generator is hilarously efficient compared to a car engine. And dirt cheap, and weighs virtually nothing. There are technical reasons for this, but basically it's not even in the same league, and produces a fraction of the emissions as a full ICE car.
You really don't need 90hp. Coasting on the freeway takes less than 10hp, depending on how big of a block you drive, so as long as the average is around that, the generator can keep the battery charged forever, and the battery handles any surge in power you need. It's only a problem if you drive like a jerk, and floor it out of every light or speed down the highway at 100+mph, and do it long enough to drain the battery.
But the brilliant part is that you can design the generator motor for single, constant RPM. I can't emphasize how much easier and more efficient that makes everything, vs. having to engineer a huge power/rpm range that can handle a dynamic load.
Still, there is a weight penalty depending on how much range they try to squeeze in.
And I'm one of those people that gets super salty about ICE cars getting so heavy too, especially crossovers and city SUVs that everyone seems to run now. A small or mid sized SUV should not be 4,000lb with modern tech, ICE or not.
xkcd #2948: Electric vs Gas ( xkcd.com )
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