Presentation Details
| Performance Calibration of Multi-Busbar and Busbar-Less Industrial Silicon Cells Using a Home-Built Reconfigurable Probing Chuck Nikos Kopidakis1, Jeremy Brewer1, Idris Davis1, Rafell Williams1, Harrison Wilterdink2, Nicholas Degenhart2, David Hinken3, Karsten Bothe3, Tao Song1. 1National Laboratory of the Rockies, Golden, CO, USA.2Sinton Instruments, Boulder, CO, USA.3Institut für Solarenergieforschung (ISFH), Hameln, Germany |
Abstract
The remarkable advances in silicon PV cell technology have created new challenges for the accurate testing of the performance of these cells. Champion efficiencies are no longer reached by lab-scale cells (few cm2 area), but by full-size M10 or G12 cells. The need to decrease silver use has led to multi-busbar cells with busbars barely wider than the grid fingers or to the elimination of busbars altogether in busbar-less cells. Silicon cells are now almost always bifacial, with busbar patterns in the rear of the cell similar or even identical to the front. The challenges of measuring the performance of these cells accurately, reproducibly, and in a way representative of their behavior in a module have already been recognized. Due to the resistance of the narrow busbars, the exact placement of contacts for current collection and voltage sensing is critical. Commonly used pin-type contacting can be designed for correct contact placement but causes significant shading. Additionally, pin-contacts often suffer from poor reproducibility when placed on narrow and intermittent busbars, and are not even applicable to 0BB cells. An additional challenge for PV performance calibration laboratories is that a contacting scheme must be reconfigurable to accommodate the wide range of cell sizes and metallization patterns encountered in practice. Here we describe a home-built probing station, the industrial Silicon Cell Contacting Chuck (iSiC3), for contacting both m-BB and 0BB cells. We show the contacting hardware and describe how it can be reconfigured for any cell size up to G12 and any metallization pattern and demonstrate improved reproducibility of contacting m-BB cells using iSiC3 compared to pin-type contacting. For a first validation of the iSiC3 contacting system, we compare performance results on 4 industrial silicon cells between NLR and the ISFH CalTeC calibration laboratory and show good agreement within the estimated measurement error.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.