Car manufacturer Toyota announced that it is collaborating with NEDO and Sharp Corporation to experiment with a Toyota Prius that can be charged using rooftop solar panels. The research should help increase the range through such a system and increase the efficiency of solar-panel electric vehicles.
Within the project, solar panels with a conversion efficiency of 34% will be used. These panels were previously developed as part of a project led by NEDO, within which a built-in solar panel was designed. This panel was placed by Toyota on the roof, bonnet, tailgate and other parts of the Prius PHV. Together, the solar panels produce an output of 860 watts, which is about 4.8 times more than the commercial version of the Prius PHV with solar panels.
Charging while driving and parking
Using the solar panels, the test vehicle can be charged while driving as well as while parked. This increases the output of the solar panels and thus both the vehicle's range on electricity and its consumption of traditional fuel. In addition to an electric motor, the Prius PHV also features a traditional internal combustion engine.
The vehicle will be tested on public roads in several regions in Japan from the end of this month, including in Toyota City in Aichi prefecture near Tokyo. During the project, data will be collected to further develop and refine the solar system. Some of this data is shared with NEDO and Sharp. The benefits of the system will be assessed by the PV-powered Vehicle Strategy Committee, sponsored by NEDO and others.
The Toyota Prius PHV with solar panels (source photo: Toyota)
Already available with solar panels
Incidentally, the Toyota Prius PHV has long been available with a so-called 'Solar Roof'. This option costs 2,895 euros and covers the roof the vehicle with solar panels. However, at 22.5%, the efficiency of these panels is a lot lower than the new panels Toyota is now experimenting with more. They also have a limited output of 180 watts and a range of 6.1 kilometres.
In addition, the solar panels on the existing Prius can only charge the batteries while the vehicle is parked; it does not charge while driving. Stored energy is used to charge the 12-volt battery that powers the navigation system and climate control.
Lightyear
Recently, Lightyear also launched a vehicle with solar panels: the Lightyear One. With this, the Dutch company claims to be marketing the first solar-powered car suitable for long distances. The Lightyear One features solar panels on both its roof and bonnet, which can be used to charge the vehicle's batteries while driving. This allows the vehicle to achieve a range of 725 kilometres.
With the vehicle, Lightyear aims to address some of the limitations of existing electric cars. For instance, electric cars must be charged using a charging station, to which the vehicle is connected by cable. However, the availability of charging stations is currently limited, which means that charging cannot be done at every location.
"Lightyear One does not suffer from these drawbacks. The car is ultra-efficient. As a result, you can drive an unprecedented 725 kilometres with a relatively small battery. In addition, the battery recharges itself using solar energy, allowing you to charge up to 20,000 kilometres a year. This makes charging a lot easier, as you can cover longer distances with the same energy. You can also use regular sockets; with a regular 230-volt plug, you can charge up to 400 kilometres a night. That's especially nice if you want to go on a road trip, because you don't have to use the electric charging infrastructure," Lex Hoefsloot, CEO and one of Lightyear's founders, said during the presentation of the prototype.
Author: Wouter Hoeffnagel
