Photovoltaic, charging electric cars with the sun while they are parked? Spanish scientists have figured out how to do it

Electric cars equipped with photovoltaic cells to recharge using solar radiation from buildings and other objects while they are parked.

Science has long been wondering how to integrate electric vehicles with photovoltaic panels, but the limited available surface area and variable conditions due to travel place significant limits on this technology.

In a study recently conducted by the Polytechnic University of Madrid, published in the scientific journal Solar Energy Materials and Solar Cells, a model is proposed to simulate direct and diffuse solar radiation on photovoltaic panels integrated into electric vehicles, with the aim of optimizing charging even when the vehicles are parked.

So-called Vehicle Integrated PhotoVoltaics (VIPVs) face challenges linked to the irregular shape of the vehicle, its movement and obstacles present in the urban environment, which can influence its performance. This model has as its main objective the increase of the autonomy of electric vehicles (EV) through the installation of photovoltaic cells on the surfaces of the chassis.

To meet the needs of vehicles, the modules must be light, resistant to operating conditions (such as vibrations and shocks) and, last but not least, comply with safety and aesthetic criteria. Modeling the energy performance of VIPVs is complex due to these variable conditions. For this reason one was developed instrument based on LiDAR data (Light Detection and Ranging), a remote sensing technology that uses laser pulses to measure distances and obtain detailed information about the surrounding environment, now commonly used also by robot vacuum cleaners. This technology simulates the performance of the modules taking into account shading, diffuse and reflected radiation.

In particular, the model studies the reflections coming from surrounding buildings. The study proposes a methodology to estimate solar radiation using a practical case: a vehicle parked near office buildings. Since a vehicle spends most of its time parked, it can receive a significant amount of reflected solar energy.

A fisheye camera capable of taking high-quality hemispherical images was positioned on the roof of the vehicle, together with a sensor developed to measure irradiance on five surfaces of the vehicle: bonnet, roof, trunk, left door and right door.