With a recent spate of new solar cell records announced for PERC-based architectures pushing conversion efficiencies past 24%, it is a good time to reflect on the pioneering work at SolarWorld – the first to commercialise and ramp PERC to volume production. A special in-depth paper from former members of SolarWorld’s R&D and manufacturing team should be a compelling read and a leading reference paper in the future. Adding to the PERC-based theme is the paper from ISC Konstanz, providing further real world insight into achieving manufacturability of nPERT cells with conversion efficiencies approaching 23%.
Welcome to Photovoltaics International 41. An emerging theme in the industry further downstream is the growing variety of bankable PV modules. It’s a topic we’ll be picking up on 23-24 October at our PV ModuleTech conference in Penang, Malaysia. This issue of PVI captures the ongoing work to drive improvements across the full range of those technologies. From the exploration of next generation CIGs cells to the commercial improvements of PERC by Trina Solar, this edition neatly captures that variety. Fraunhofer ISE reviews the latest results from efforts to improve the texturing of diamond wire sawn wafers. Trina Solar presents a roadmap for PERC improvements that it claims could halve costs while pushing efficiencies to 24% in around seven years. ECN and imec explore the latest developments in integrated cell to module manufacturing approaches from the more familiar multi-busbar and multi-wire to shingling and woven fabric and foil-based module technologies for back contacted cells. Elsewhere, CSEM INES zooms in on a major limiting factor for silicon heterojunction cells, metallization. All the regular features including our news reviews and R&D spending report make a return, plus lots more. Following on from this bumper edition, PVI42 will be published in Spring 2019.
Welcome to the tenth anniversary edition of Photovoltaics International. Over the past decade this journal has documented the latest developments in the fast-changing of world PV technology, bringing you exclusive insights from researchers working at the industry’s cutting edge. Over that time the pace of change has been astonishing, so much so that it scarcely seems as though one new technology is accepted before the next arrives on the scene. So seems to be the case with the passivated emitter and rear cell (PERC), which having become the technology upgrade of choice across the industry now appears to have a successor in waiting. In this edition researchers at Fraunhofer ISE look at so-called tunnel oxide passivated contact (TOPCon) technology as a follow-up to PERC. Meanwhile, a team from TÜV Rheinland takes a deep dive into the vexed question of how the industry can most usefully define the benefits of bifacial technology. At the other end of the value chain, US-based 1366 Technologies gives an account of its contribution to reducing costs in wafer manufacturing, a significant ongoing expense in industrial PV cell production and thus a key focus for efforts to drive down the levelized cost of solar-generated electricity. Elsewhere in this edition, Canadian Solar outlines some of the solutions it has developed for tackling light-induced degradation in multi-PERC cells and modules, a persistent challenge with PERC technology. In this edition our deputy editor Tom Kenning reports from the recent PV CellTech event in Malaysia, where the ‘Who’s Who’ of the PV manufacturing world gathered to debate the current state of play in solar technology.
Welcome to the thirty-ninth edition of Photovoltaics International. We go to press just a few days after the conclusion of our PV CellTech conference in Penang. The focus for all the PV CTOs, chief scientists, materials providers, equipment manufacturers and others gathered for the summit was how to keep pushing the industry towards a standard 20% efficiency while also expanding in scale. That expansion ought to be 100GW in three years if demand is to be met, according to one speaker. CEA-INES researchers look at the benefits of exploiting the symmetrical a-Si/c-Si/a- Si structure of silicon heterojunction cells to use ultrathin wafers. Another innovation that delivers materials savings is of course diamond wire sawing and, again, scale and efficiency are dual drivers. Here, CEA demonstrates the need for, and processes involved in, closely monitoring the cutting process to ensure wafer quality is consistent and productivity can remain at the desired level. We look at different sides of bifacial technology (pun intended) starting with JinkoSolar’s appraisal of its mono PERC bifacial cells built using standard production technology and racking up average efficiencies of 21.8%. Away from the crystalline silicon world, German research firm OPVIUS explores how a combination of printing methods could open the door to freeform PV modules, unleashing an entirely new suite of product options and applications. ECN Solar reveals the results of an industrial-scale trial process to develop an n-type bifacial IBC solar cell that is based on tube diffusion and a simultaneous single-step screen-print of contacts at both polarities. Last but not least, CSEM looks at the impact the emerging diversity in cell technology and module architecture is having on metrology.
Welcome to the 38th edition of Photovoltaics International. There is every sign that 2018 is going to be a huge year for the industry as manufacturers continue investing in new tools and technologies. We will doubtless see many of the innovations whose evolution has been documented in these pages becoming increasingly mainstream. Sticking with bifacial solar, Fraunhofer ISE takes a wide-ranging look at a number of challenges surrounding the technology’s leap to widespread deployment. The Institute for Solar Energy Research Hamelin (ISFH) and Meyer Burger Technology AG present a novel bifacial module architecture. The University of New South Wales, Trina Solar and BT Imaging give a suggestion for predicting the variation in multicrystalline cell performance by measuring the bulk lifetime of ingots. We also have a look at PV recycling and lifecycle management from First Solar, PI Berlin’s assessment of PID issues in thin-film solar and TongWei presents a roadmap for PERC cells with 22% efficiency.
As always we have a selection of technical papers from some of the industry’s leading minds. Radovan Kopecek and Joris Libal from ISC Konstanz tackle one of the biggest issues impeding the rollout of bifacial cell and modules, how to standardise their measurement. As long as there is no commercially available means to measure their gain, bifacial modules will struggle to improve their market penetration. The materials section includes an excellent paper from Fraunhofer THM examining the optimization of diamond wire sawing. The method is becoming increasingly predominant with some equipment manufacturers shelving their slurrybased tools. Here Fraunhofer assesses how to squeeze even more efficiency out of diamond wire saws. CSEM meanwhile explores the required metallization and interconnection process changes required to enable a production-scale shift to silicon heterojunction PV. Mark Osborne provides his latest capacity expansion report as upgrades to higher efficiency lines continue to drive planned investments.
In this issue of Photovoltaics International Fraunhofer ISE presents a concept for a bifacial, shingled cell technology that it claims tracks a cost-effective route to a 400W module using existing industrial-scale concepts. Also one trend now much more than a notion is the ongoing switch to monocrystalline cell technology. Meanwhile the University of New South Wales pulls together and critically assesses the raft of research on perovskite PV technology. Following the success of our PV CellTech conference, we’re also introducing our new PV ModuleTech event focusing on the technology that turns completed cells into supplied modules in the commercial market.