The main problem with any EV is that if one that could have the equivalent mileage and range per weight/volume/mass of a gallon of gasoline... in some sort of "battery", it would make a damn nifty bomb if it malfunctioned. .
There's a lot of joules/wattage/therms... whatever you want to use, in gasoline. roughly 130 MJ/US gal, or 37 kWh/US gal) It's the concentrated effort of billions of watt hours of sunlight, megatons of simple plants and animals, and aeons of unimaginable temperatures and pressures due to geology.
IIRC, the best commercially feasible LiOn batteries to date have about 115 Wh/lb. Whereas Gasoline is about 617 Wh/lb.
So in a very crude estimate, not counting for transmission losses etc. or what it means to the power grid infrastructure, or new power plants, current battery tech will have to improve by a factor of roughly five or six times the current state of the art to make EV's truly feasible as a replacement for gasoline IC engines.
We're probably still going to need to see an increase of around three to four times the current state of the art in battery energy density.
I think you dropped a zero.
Gasoline is 46.4 MJ/kg, which is 5860 Wh/lb, or closer to 40x batteries.
Assuming transmission and road losses are the same, a 33% ICE efficiency, and giving EV's a 50% bonus from regenerative braking and more efficiency at part throttle (note, part-throttle pumping losses can be eliminated as BMW did with their no-throttle VANOS, or with a diesel, and stop-start on engines eliminates the idle penalty), batteries would still need a 10x improvement to match energy density. Of course, the actual drive system is lighter with an EV, so that mass can be used for battery, so let's give the EV another 100% benefit when comparing total fuel+drivetrain mass, and it's still 5x (1265 Wh/kg). Now, some proposed flow-through batteries, coupled with pulsed peak storage (advanced ultracaps) -could- achieve this. But unless it's nuclear or some other non-CO2 emitting plant on the other end of the grid, the carbon footprint remains roughly the same...or worse, as a coal plant emits 1.5-2x the co2 as a modern advanced diesel for a given energy output (and I'm also neglecting the charge/discharge round-trip efficiency of the battery, power management system, motor controller, external charger, grid transport, and motor efficiency, which when combined yield a 25-30% hit on the EV).
ALSO, hydrocarbons are fungible, we can get them from just about anywhere (albeit at potentially widely varying costs), while EV's require rare earths for advanced magnets (90+% from one country, china) and lithium for batteries (75+% IIRC from one country--Bolivia)...so we replace a fungible, world-wide (and synthesizable from electricity...search for my other threads) material with a rare, non-synthesizable, potentially politically limited resource.
Overall, my vision of the future is a synthetic methanol/Dimethylether based liquid transport fuel market, powering advanced high-pressure turbocharged engines, with the fuels created from nuclear generated electricity. Ultra-high power (got to love 100+ octane), zero carbon footprint, maximum re-use of existing infrastructure, and overall better round trip efficiency with no externally politically controlled resource requirements.
