One More Step ForwardElectric vehicles, in the broad sense of the term which includes hybrids, still have a lot of room to improve. While the technologies that underpin them have been invented a long time ago, it's only relatively recently that largest amount of R&D resources have been poured into the field. While none of this is instantaneous and it takes years to go from the lab to the road, it's now been enough years since this transition to heavier investments that we should start to see the pace of improvements increase. This not only means better batteries (and for this the EV industry is partly piggy-backing on the mobile electronics industry), but also better power electronics, motors, vehicle designs, advanced materials, etc.
One small example of this is this new permanent-magnet electric motor by GE:
General Electric engineers have successfully tested a prototype hybrid and electric vehicle motor with a peak power level of 55 kW and the ability to operate continuously at up to 105 °C (221 °F), using conventional transmission fluid as the motor’s sole cooling agent.
The motor—which GE says is 3 to 5% more efficient than existing motors could potentially extend the range of a plug-in vehicle—was developed as part of a $5.6-million US Department of Energy (DOE) project, and performs well over a range of bus voltages, from 200V to 650V. (source)
It's extremely compact, with a power density about twice that of today’s motors, according to the company.
While this might not seem like much - half the size, 3-5% more efficient - this is a big deal because all of these incremental improvements compound. So you save some weight on the motor, and some energy because it's more efficient. When you combine that with other improvements, like better batteries, improved power electronics, lighter materials and better structural design, etc, you end up with a significant difference. And since people's driving habits are relatively static, at some point you reach the "good enough and cheap enough for most people point" which changes everything.