Photovoltaic or PV cells are the most important part of a solar panel. These critical components absorb photons from sunlight. PV cells work in conjunction with semiconductors built into. An aluminum frame holds all the above together. Without a frame, the panels would be prone to bending under the stress of high winds. The aluminum frame also works as a solid. Finally, a layer of EVA (ethylene vinyl acetate) film provides the solar panel's critical components with additional protection against extreme temperatures and humidity. EVA film. A layer of toughened glass covers the PV cells to form the outermost portion of the panel. This layer of glass is designed to protect photovoltaic cells from elements such as rain, sleet, snow. The backsheet is the outmost protective layer built into the bottom of every solar panel. This sheet is often white or transparent and is hardly noticeable. This backsheet helps make the.