• Back-contacted high-efficiency silicon solar cells – opportunities for low-cost metallization

    This paper presents ISFH’s recent developments and advances in the field of back-contacted silicon solar cells. The efficiency potential of back-contacted solar cells is very high; nevertheless, in industrial production, back-contacted solar cells are decidedly the minority. In the field of back-contacted solar cells, ISFH has developed several cell concepts and new processing techniques, such as laser ablation for silicon structuring, contact opening through passivation layers, and hole drilling for emitter-wrap-through (EWT) solar cells. The latest results are presented regarding ISFH’s work on back-junction back-contacted solar cells and EWT solar cells, as well as on back-contacted solar cells employing an amorphous/crystalline silicon heterojunction. Also discussed are the advances in high-throughput evaporation of aluminium as a low-cost option for the metallization of back-contacted solar cells. Finally, a novel, silver-free cell interconnection technique is presented, which is based on the direct laser welding of a highly conductive, low-cost Al foil, as a cell interconnect, onto the rear side of back-contacted solar cells.

  • Current status of MWT silicon solar cell and module technology

    This paper reviews metal wrap through (MWT) solar cell and module technology. As MWT solar cells and modules have received more and more attention in recent years, many highly efficient MWT cell types have been presented by research institutes and industry and are summarized herein. The MWT cell structure benefits from a reduced silver consumption compared with a conventional H-pattern cell, and its realization can be easily combined with novel metallization technologies such as dispensing or stencil printing. The introduction of a rear-surface passivation into the MWT structure is feasible with the high-performance MWT (HIP-MWT) concept developed at Fraunhofer ISE. The resulting fabrication sequence includes only one additional process step – laser drilling of vias – compared with an H-pattern passivated emitter and rear cell (PERC). Furthermore, the synergistic effects of MWT and PERC boost the conversion efficiency gain of MWT-PERC-type cells beyond the expected sum of what could be achieved individually from these two approaches. According to the calculations made by Fraunhofer ISE, conversion efficiencies of up to 21.5% (annealed) are feasible for p-type Cz silicon MWT-PERC cells. Because via metallization is one of the challenges in the fabrication of MWT cells, different via pastes are investigated with regard to their series resistance and contact behaviour. With cell-to-module losses in conversion efficiency of only 0.9% abs., both the interconnector-based MWT module technology and the conductive backsheet concept show promising results.

  • 20.1%-efficient industrial-type PERC solar cells applying ICP AlOx as rear passivation layer

  • Development of cost-effective PERLtype Si solar cells with 19.5% average efficiency

  • Selective emitter (SE) technology – from laboratory to optimization in full-scale production

  • Challenges for single-side chemical processing

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  • Photovoltaics International 23rd Edition

    This issue of Photovoltaics International, our 23rd, offers key insights into some of the technologies that are ready to move from lab to fab in support of these goals. ISC Konstanz offer a glimpse of what the low-cost, high-efficiency solar cells of the future might look like. On page 35 the institute’s authors give an overview of what they call Konstanz’ “technology zoo”, encompassing their so-called BiSoN, PELICAN and ZEBRA cell concepts, all of which are aimed at increasing energy yield at the lowest possible cost.

  • Manufacturing The Solar Future: The 2013 Production Annual

    In the ever-changing global solar markets, cost reduction and measures to increase cell efficiencies are the key tools available to PV manufacturers to create new opportunities and drive your business to the next level. Manufacturing the Solar Future 2013 is the third in the Photovoltaics International PV Production Annual series, delivering the next instalment of in-depth technical manufacturing information on PV production processes designed to help you gain the competitive edge.

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