Device Architecture Simplification of Laser Pattering in High-Volume Crystalline Silicon Solar Cell Fabrication using Intensive Computation for Design and Optimization

Prices of Si based solar modules have been continuously declining in recent years. Goodrich is pointing out that a significant portion of these cost reductions have come about due to ?economies of scale? benefits, but there is a point of diminishing returns when trying to lower cost by simply expanding production capacity [1]. Developing innovative high volume production technologies resulting in an increase of conversion efficiency without adding significant production cost will be necessary to continue the projected cost reductions. The Foundational Program to Advance Cell Efficiency (F-PACE) is seeking to achieve this by closing the PV efficiency gap between theoretical achievable maximum conversion efficiency - 29% for c-Si - and the current typical production - 18.5% for a typical full area back contact c-Si Solar cell ? while targeting a module cost of $0.50/Watt . The research conducted by SolarWorldUSA and it?s partners within the FPACE framework focused on the development of a Hybrid metal-wrap-through (MWT) and laser-ablated PERC solar cell design employing a extrusion metallization scheme to achieve >20% efficient devices. The project team was able to simulate, develop and demonstrate the technologies necessary to build p-type MWT PERC cells with extruded front contacts. Conversion efficiencies approaching 20%more » were demonstrated and a path for further efficiency improvements identified. A detailed cost of ownership calculation for such a device was based on a NREL cost model and is predicting a $/Watt cost below 85 cents on a 180 micron substrate. Several completed or planned publications by SolarWorldUSA and our partners are based on the research conducted within this project and are adding to a better understanding of the involved technologies and materials. Several aspects and technologies of the proposed device have been assessed in regards to technical effectiveness and economic feasibility. It has been shown in a pilot demonstration with wafer thicknesses down to 120 micron that further wafer thickness reduction is only economically viable if handling and contact formation limitations are addressed simultaneously. Furthermore the project partners assessed and demonstrated the feasibility of processing wafers with vias connecting front and back sides through a PERC cell process and aligning and connecting those vias with a non-contact metallization. A close cooperation between industry and institutes of higher education in the Pacific Northwest as shown in this project is of direct benefit to the public and is contributing to the education of the next generation of PV engineers and scientist.« less