I'm with you there. Electrochemical storage technology has not experienced a necessary quantum leap from 19th century technology. The lead acid battery hasn't changed at all since the Civil War!
However, within the constraints of the EPA game, there's some room for batteries as a motive storage device.
And if you're going to do it, and if you really need >40mpg (we don't), then all I'm saying is that a serial hybrid makes more sense than a parallel hybrid, and less pollution than an ultra-lean diesel.
Yeah, until the batteries catch fire on you.
The safety of lithium batteries is still up in the air, as the occasional laptop fires show. Huge piles of lithium cells in an accident could be really bad for you, if you are in the car. Gone in seconds comes to mind.
I saw an engineering analysis(can’t remember where) that showed battery power, pound for pound, delivered about 1/25 the energy to the rear wheels as gasoline.