ماژول های فتوولتائیک و استفاده از اتصال خمیر گالینستان
I- INTRODUCTION
II- EXPERIMENTS AND DISCUSSION
III- CONCLUSION
REFERENCES
INTRODUCTION
A solar cell is a semiconductor device that converts light energy into electric energy and should be manufactured in the form of a module to function for a long time without being affected by exposure to external environments. In a typical solar cell module, solar cells are connected in series with each other by using a ribbon. Materials such as ethyl vinyl acetate (EVA), back sheet, and glass are laminated by applying heat on both ends of the solar cells for protection, and finally, the module is completed within a frame [1]. At this point, the loss that occurs during the manufacturing process of the solar cell module depends on the resistance of the ribbon that connects the solar cell, the contact resistance between the ribbon and the solar cell electrode, the shadow loss due to the electrode and the ribbon, and the area loss occurring at the in tervals between the solar cells [2–4]. One of the ways to reduce these losses is to fabricate a module by using a laser to cut high-efficiency solar cells within each unit cell and then connect the unit cells directly within a shingled structure without using a ribbon [5, 6]. The shingled module has the advantage of producing more electric power per area than currently commercialized modules because the former eliminates the contact resistance due to the ribbon, the shadow loss caused by the busbar and the gap between each solar cell. A pattern different from that of a conventional solar cell is used to fabricate a shingled module. Because the busbar of a conventional solar cell exists at the same position on both sides of the solar cell, the ribbon is connected in a serial connection, but the busbar of the unit cell used for the shingled module is located at the edges of both sides of the cell. Therefore, each cell is connected using electrically conductive adhesives (ECAs). In this case, the ECA, which is a conductive epoxy material, has high electrical conductivity, a high content of silver and a high unit price and should be stored at −20◦C to prevent epoxy hardening [7]. Additionally, because the shingled module is heated and cured during the fabrication process, cell breakage or damage may occur [8,9]. Therefore, when fabricating a solar cell module by using the liquid metal Galinstan as a connecting material for a thin crystal silicon solar cell, damage due to the difference in the thermal expansion coefficients between the cell and the ribbon can be prevented [10]. Because Galinstan is much cheaper than Ag particles, Galinstan as an interconnection material has an advantages in fabrication cost. Moreover, by using liquid silicone, breakage that may be caused by the difference between the manufacturing of the shingled module and the unit cell may be prevented. In this study, we fabricated a shingled module by using Galinstan paste and liquid silicone and confirmed any damage that might have occurred during the manufacturing of the module, as well as the differences in the module’s characteristics.