Investigation of Screen-Printed Copper Metallization Interconnection and Durability in the HJT Solar Cell and Module
article
This study reports progress in screen-printed copper (Cu) metallization (Cu paste with 0% Ag content) for silicon heterojunction solar cells (HJT), fully replacing the conventional silver-based metallization. Important performance requirements for practical application were tested and demonstrated. A line width of less than 20 μm was achieved, which implies it is suitable for use on the front side of a solar cell. Cell-to-cell interconnection by use of low-temperature soldering was demonstrated with sufficient material adhesion. Selected accelerated degradation tests (damp heat and thermal cycling) showed Cu metallized HJT cell and module stability within IEC test thresholds. The optimized Cu metallization resulted in less than 0.5% power loss compared to silver (Ag) metallized reference cells; a peel force for the interconnection tabs of 1.0–2.0 N/mm comparable to the soldered Ag contact. After 200 thermal cycles (cf. IEC standard 61215), Cu-metallized HJT single cell modules showed an average ∼2.7% power loss, mainly due to a reduction in fill factor. In the Cu contact durability test at cell and module level, only minor losses in voltage and pseudo fill factor were measured, from which we assess there was no detrimental Cu diffusion into the active cell layers. Both Ag and Cu metallization based single cell modules, provided with and without edge sealant, showed less than 5% power loss after 1000-hour damp heat testing, which meets the IEC 61215 standard, though the modules without edge sealant with Cu-metallized cells showed more degradation than the other three types of modules.
Topics
TNO Identifier
1029039
Source
IEEE Journal of Photovoltaics
Publisher
IEEE Electron Devices Society
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