| Work Detail |
Researchers at Fraunhofer ISE have demonstrated for the first time the feasibility of the shingling method with perovskite-silicon tandem solar cells. They also produced full-format photovoltaic modules with a power conversion efficiency of 22.8%. A group of scientists led by Germanys Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) has attempted to apply shingling interconnection technology to perovskite-silicon tandem (PVST) solar cells for the first time. “The combination of PVST cells with tiles allows to further increase the efficiency of the module due to the increase in the photoactive area due to the absence of spaces between the cells,” the lead author of the research, Veronika Nikitina, told pv magazine . “Technologically, the Shingling system adapts to the temperature limitations of PVST cells, since the main factor for the choice of processing temperature is the curing conditions of the electrically conductive adhesive.” Tile panels feature a barless structure in which only a small proportion of cells are not exposed to sunlight. The cells are joined together with an electrically conductive adhesive to form a chain of high-density tiles and the resulting strips are connected. The reduced number of bars reduces shadow losses. “A significant advantage of combining PVST cells and tiles is the relaxation of finger resistivity requirements due to the relatively low current density of the cells,” the scientists said. “In addition, the tile does not use tapes and requires only one side of the cell to be printed with electrically conductive adhesives (ECA).” They also emphasized that the tiles use less material while reducing thermomechanical stress on the panels. It also increases the active area of ??a cell, thereby increasing the devices fill factor and power conversion efficiency. Additionally, solar modules with shingles have improved shading resistance compared to products without shingles. The researchers used M6 (166mm x 166mm) precursors with a two-terminal (2T) configuration provided by solar perovskite specialist Oxford PV. Low-temperature silver paste metallization using 60-finger continuous busbar screen printing was carried out at Fraunhofer ISE, while cell cutting into 1/5 tiles with an efficiency of 24.5% was carried out at the Oxford PV plant in Brandenburg, Germany. The tiles were sent back to Fraunhofer ISE in Freiburg for interconnection and module integration. “The optimal number of fingers at the front was determined by sweeping the number of fingers while keeping the number of fingers at the rear constant, as well as the dimensions of the fingers and bus bars,” they also explained, noting that they used cell-module (CTM) analysis to evaluate the impact of the number of fingers and the size of the tiles on the module efficiency. Through their analysis, the scholars found that 1/6 cut-off PVST cells with an initial tile cell efficiency of 25% could achieve a module efficiency of 23.4%. “The feasibility of the shingling approach, as well as the integration of modules with PVST cells, was demonstrated through the production of full-format modules,” the group said, adding that it produced real bifacial glass-glass solar panels based on production equipment industrial, which achieved efficiencies of up to 22.8%. “The metallization of PVST precursors with silver paste at low temperature using screen printing, followed by laser cutting and mechanical cutting, was a success.” |
