The solar cells are encapsulated above and below with EVA, which stands for ethylene vinyl acetate. The cells are compressed between EVA layers at 150 degrees C under pressure, effectively sealing them from contaminants. It also acts as a shock absorber on both sides of the delicate crystalline structure.
The Relative Density of EVA is 0.92 to 0.94 g/cm 3, so it is lighter than water, with a RD of 1. EVA doesn’t contribute much weight to the panel at all, just a few ounces at most.