Answer: Solar cells.
By adding the technology to its plug-in hybrid Prius, the car-maker has given its well-known hybrid vehicle three distinct sources of power.
This isn’t the first time that Toyota has added solar panels to its Priuses — the Japan-only 2016 Prius PHV got them — but this new design is capable of five times more power generation than the previous version. The solar panels themselves are thinner, at just 0.03 mm, allowing them to be installed on curved surfaces so they can cover the entire length of the hood, roof and rear hatch. Additionally, the panels convert solar energy at a rate of 34 percent efficiency as compared to a previous 22.5 percent.
Most notable, however, is that where the previous vehicles had to be parked in order to charge from their solar panels, the latest iteration is capable of charging while the car is moving. If parked in the sun for a full day, the panels will generate enough power to give the car an additional 27 miles of range. Toyota has scheduled road tests for later this month that should provide more details into the car’s improved efficiency.