Could Radioisotope Thermoelectric generators power electric cars?

[nite owl]

TL;DR Summary

RTG for electric cars.

Could electric cars be given longer range by radioisotope thermoelectric generators like they use to power spacecraft in deep space?

 

[Drakkith]

The last thing you want on a vehicle is an inefficient radioactive power source just waiting to be cracked open by a collision. Or by inept mechanics, ignorant owners, or terrorists.

 

[PeterDonis]

Could electric cars be given longer range by radioisotope thermoelectric generators like they use to power spacecraft in deep space?

Aside from the concern about radioactivity that @Drakkith raises, I believe these generators are too low power to be useful for an electric vehicle.

 

[Astronuc]

Summary: RTG for electric cars.

Could electric cars be given longer range by radioisotope thermoelectric generators like they use to power spacecraft in deep space?

Complementing concerns raised by Drakkith and PeterDonis, indeed the power densities are too low to be practical for mass transportation/propulsion.

https://en.wikipedia.org/wiki/Radio..._generator#Criteria_for_selection_of_isotopes
Pu-238 is chosen for its relatively long half-life, much longer than typical missions. Its power density is ~
0.54 W/g or 0.54 kW/kg. Taking the power for a 2016 Honda Civic (158 - 174 hp / 118 - 130 kW), this would require 218 to 240 kg Pu-238, which is a fair amount of mass for a car. Other isotopes with higher power density, e.g., Po-210, would require much less mass, but the half-life is relatively short, e.g., 138 days, so the power level decreases fairly quickly.

Radio-isotopes are quite expensive! Pu-238 costs ~$8 million per kilogram.
https://ne.oregonstate.edu/rebuilding-supply-pu-238

A major disadvantage of a radioactive source is the fact that they decay continuously, so they are always on. When not driving, one would have to plug the generator into the grid to dump the power, or otherwise remove the heat. It would be a great heat source in winter.