A press release by Panasonic outlines their newly developed HIT Photovoltaic Module designed for the Toyota Prius PHV, which generates power and charges the drive system batteries. Previously solar roofs have been limited to powering accessories and auxiliary charging of the 12 volt batteries, however the higher output solar cells Panasonic has created are capable of charging the higher voltage drive system lithium-ion batteries as well.
The new batteries aren’t restricted to the typical flat and boxy shapes we’re typically used to seeing, and can take on a curved design to flow with the body panels of the recipient vehicle.
While a solar panel was mounted on the Prius HV in 2012, the limited output of the panel did not contribute toward the range of the vehicle. With the new HIT panels, they have achieved an output of approximately 180W which is three times the output of the predecessor.
When you put all of these things together, you have a nicely packaged optional feature which may replenish the range by a few miles and further increase the efficiency of the vehicle overall.