The present disclosure provides a functional part, a photovoltaic module and a method of manufacturing photovoltaic modules. The functional part is configured to form a photovoltaic module with a cell string that includes a plurality of cells. Adjacent cells of share an overlapped region. The functional part has a first surface facing the cell string and a second surface opposite to the first surface. The functional part includes at least one groove extending from the first surface toward the second surface. A location of each groove corresponds to a location of at least one overlapped region.