LIFETIME ANALYSIS OF BIFACIAL-READY CONTACTING OF BUSBARLESS AND MULTIBUSBAR SOLAR CELLS FOR INDUSTRIAL MASS PRODUCTION

摘要

In our contribution, we evaluate two variants of a bifacial-ready contacting solution for busbarless and multibusbar solar cells with regard to their lifetime and the effect of repeated contacting on a single cell. Our contact solution is named universal contact probes (cetisPV-CF-ucp) as they are universally applicable to all kinds of silicon solar cells. We assess their lifetime using the stability and reproducibility of IV and EL measurements during a long-term test over 8 million contacting cycles. Our results demonstrate a strong impact of the surface morphology of the probes on the contacting quality achievable in the long-term test. Variant two of the probes achieves stable FF measurements and fulfills industry requirements on repeatability and accuracy over a lifetime of 8 million cycles, whereas variant one which differs only in the surface morphology of the contacting area fails after a few hundred thousand cycles. To investigate the effect of repeated contacting on solar cells we examined visible marks left in the cell metallization and electrical degradation upon frequent contacting determining the usability of cells as calibration references over a larger number of contacting events (up to 10~6 cycles). In the end, we provide a method for a reliable and fast assessment of the local and global contacting quality of each probe bar during maintenance and commissioning.