Self-Charging Cars

Back in 2010, Toyota developed a solar power system for the roofs of their Prius hybrid-electric vehicles (HEVs). The goal behind the initiative for Toyota was to see if a vehicle’s rooftop would provide enough solar power to charge the vehicle’s battery, providing drivers a few extra miles before the next charging session. According to Toyota, it was the company’s first steps towards producing a self-charging car. But the solar cells implemented into Toyota’s photovoltaic system provided just enough power to run auxiliary devices such as the power steering pump, ventilation fan, and air-conditioning compressor. This was due to the fact that the solar cells generated a capacity of only 50 watts.

Compare this with the design of the Lightyear One created by a startup company based in the Netherlands. Total peak output is 1.25kW which is enough power to provide anywhere between 20 – 45 miles of average range per day, according to Lightyear. Lowie Vermeersch created the design of the Lightyear One and an engineering firm based in Germany – Aachen – helped develop its integral 60-kWh battery system. The strategy, according to Lightyear’s chief technology officer, Arjo van der Ham, was their clean-sheet, systems-engineered approach.  This meant a propulsion motor at each wheel, lightweight materials, advanced aerodynamics, and enough sky-facing surface area to host about 1,000 photovoltaic cells. As Eric Wesoff of PV Magazine points out, the challenge to accomplishing the goals of aerodynamic efficiency and solar power efficiency lies in the design. He explains that you want a car that can both charge itself, which would require a broad area for the PV cells, yet remain aerodynamically efficient, which would require a narrow body design.

This is where Lightyear stayed true to its systems approach and the company believes it addressed this challenge in competing design goals. Lightyear believes it has met the challenge by integrating the motors with the suspension via a propulsion motor in each wheel and by making adjustments to the battery size. Lightyear also believes that they have now provided a solid architecture that other companies will use in the future as they push towards self-charging cars.

Taken from: www.sae.org

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