The difference between polycarbonate sheet and glass. This is a typical coefficient of thermal expansion for all plastic sheets: polycarbonate sheet is 0.065 mm/m°C. Let me assume that you have installed the board in an area where the temperature difference between the hottest day of the cold summer and winter days is 55°C This means that the size of the paper differs by 55x0.065=3.575mm per meter of board length/width change.
This difference is absorbed by the system used to install the board. In most cases, the polycarbonate plate is sandwiched between aluminum glass rods, which usually have a notch depth of 20 mm and allow some action inside the glass system of the piece. Other types of glass systems can of course also be used, as long as he extends this to the account. In case of doubt, you can refer to the technical documentation of the supplier of a polycarbonate solar panel.
