Electric-car battery progress: incremental improvements, not revolutionary leaps

Tesla Motors - Model S lithium-ion battery packThe report that Toyota is planning an electric car with a solid-state battery for 2022 has led some fans and advocates to suggest huge new leaps in electric cars are imminent. The 2011 Nissan Leaf had an EPA-rated range of 75 miles combined; the comparable figure for a 2017 Chevrolet Bolt EV is 238 miles. That's remarkable progress, and clearly...