Mono vs multi, n-type vs p-type: outlooks from PV CellTech 2018

By Tom Kenning, deputy editor, PV Tech

PV CellTech has become the upstream PV industry’s foremost annual event. This year, a key topic for discussion was whether n-type silicon would trump p-type as manufacturers look to drive up efficiencies, as well as the inevitable debate over the relative fortunes of multi and mono technologies. Tom Kenning reports from the event.

Four-terminal perovskite/c-Si tandem PV technology

By Dong Zhang, ECN part of TNO – Solliance, Eindhoven; Stefan Luxembourg, ECN part of TNO, Petten, The Netherlands; Gianluca Coletti, ECN part of TNO, Petten, The Netherlands; Sjoerd Veenstra, ECN part of TNO – Solliance, Eindhoven; Bart Geerligs, ECN part of TNO, Petten, The Netherlands

Two factors have coincided to stimulate the recent spur in interest for hybrid tandem PV technology based on crystalline silicon – the fact that balance-of-system (BOS) costs are increasingly dominating turnkey system costs, which strengthens the effect of high efficiency in reducing Wp costs, and the discovery of perovskite solar cells as a promising low-cost wide-band-gap partner for crystalline silicon (c-Si). This paper presents the progress and analysis of four-terminal (4T) perovskite/c-Si tandem technology at ECN part of TNO, with perovskite technology development carried out within the Solliance research organization.

PV manufacturing capacity expansion announcements in Q1 2018

By Mark Osborne, senior news editor, Photovoltaics International

PV manufacturing capacity expansion announcements in the first quarter of 2018 continued to mirror those of the previous two years, highlighting the recent trend of the last quarter and the first quarter of each year (since the end of 2015) being the most active. The quarter being discussed also represents a revival in thin-film expansion plans, the return of PV module assembly outpacing solar cell announcements and the return of India and the US as major destinations for new capacity plans.

The opportunity for wafer-based reduction in LCOE

By Adam Lorenz, 1366 Technologies, Bedford, Massachusetts, USA; Jochen Rentsch, Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany; Sebastian Nold, Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany; Todd Templeton, 1366 Technologies, Bedford, Massachusetts, USA; Laureen Sanderson, 1366 Technologies, Bedford, Massachusetts, USA

As the PV industry strives to reach terawatt scale, addressing the last remaining cost centres of the crystalline silicon value chain will play a critical role in ensuring that the industry can continue to achieve lower systems costs, and provide the extremely low levelized cost of electricity (LCOE) required to drive the adoption of this form of energy. Wafer manufacturing remains the single largest cost driver in industrial cell production. While incremental improvements, such as diamond wire (DW) sawing, have helped to lower silicon consumption, wafer manufacturing has lacked the significant step change necessary for achieving dramatic cost reduction.

Solutions to realizing LID-controlled multi-PERC cells and modules

By Fangdan Jiang; Jan-Nicolas Jaubert; Daqi Zhang; Zheng Yao; Guangyong Xiong; Jian Wu; Guoqiang Xing, Canadian Solar Inc., Suzhou, Jiangsu, China

State-of-the-art black-silicon texturing technology has been successfully implemented in all of the 4.5GW multi-Si cell production lines at Canadian Solar (CSI). With a combination of black-silicon texturing and diamondwire-sawn wafers, it has been possible to increase cell efficiency and wattage, while significantly reducing the cost. To further improve CSI’s multi-Si product performance and cost, multi-Si passivated emitter rear contact (multi-PERC) technology has been developed to achieve a mass production cell efficiency of more than 20% on average, and a module power exceeding 300W. By the end of 2017, a production capacity of over 1GW had been established, and CSI’s majority multi-Si cell capacity will be upgraded to PERC in 2018. This paper will introduce the solutions to realizing light-induced degradation (LID)-controlled multi-PERC cells and modules, as well as offering a discussion of the degradation performance. In addition, the technology evolution of CSI’s high-efficiency multi-Si products and a roadmap for 22%-efficiency multi-Si cells are presented.

Power rating and qualification of bifacial PV modules

By Xiaoyu Zhang; Christos Monokroussos; Markus Schweiger; Matthias Heinze, TÜV Rheinland Group

The extra energy gain offered by bifacial PV modules has helped make them an increasingly popular choice in the global PV industry. But the question of how to define, measure and rate the electrical output from bifacial modules is a hotly debated topic, given the extent to which the rear-side contribution is dependent on a range of variable factors relating to local environmental conditions and system configurations. Drawing on in-house modelling and simulation software developed at TÜV Rheinland, this paper explores the power rating issue for bifacial devices, examining the definitions of rear irradiance, measurement test method, power stabilization and verification for type approval. Relevant reliability and safety tests are discussed, with additional modifications and suggestions for bifacial PV modules.

Challenges for the interconnection of crystalline silicon heterojunction solar cells

By Angela De Rose; Torsten Geipel; Denis Erath; Achim Kraft; Ulrich Eitner, Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany

Crystalline silicon heterojunction (HJT) solar cells and modules based on amorphous silicon on monocrystalline wafers offer advantages over established wafer-based technologies in terms of efficiency potential, complexity of the manufacturing process, and energy yield of the modules. The temperature sensitivity of these solar cells, however, poses considerable challenges for their integration in modules. Currently, there exist three approaches for the interconnection of HJT solar cells, each with its own strengths and weaknesses: 1) ribbon soldering with low-meltingpoint alloys; 2) gluing of ribbons by using electrically conductive adhesives (ECAs); 3) SmartWire Connection Technology (SWCT).

Towards industrial manufacturing of TOPCon

By Frank Feldmann; Sebastian Mack; Bernd Steinhauser; Leonard Tutsch; Jana-Isabelle Polzin; Jan Temmler; Anamaria Moldovan; Andreas Wolf; Jochen Rentsch; Martin Hermle; Stefan W. Glunz, Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany

TOPCon is regarded as a possible follow-up technology to the passivated emitter and rear cell (PERC) concept. This paper presents the latest results for high-efficiency solar cells, and the progress made on migrating layer deposition to high-throughput tools, which are already in use in industry. Possible metallization approaches, and three different industrially relevant solar cell structures featuring TOPCon, are also discussed.

The Most Efficient and Adaptable Solution Design for Bifacial Modules

Leading PV inverter manufacturer Huawei discusses recent technical developments to a better understanding of bifacial solar module PV power plants, using three recent case studies. These efficient PV modules need to be used with devices such as inverters to maximize value. Recently, many inverters and solutions that match bifacial modules have appeared in the industry. Which solution is the best match for bifacial modules? Based on a large amount of experimental data, this article describes the solution needed for bifacial modules.

Polysilicon consumption to decline below 4g/W in Q3 2018

By Finlay Colville, Head of Market Research, Solar Media

The in-house market research team at PV Tech, this journal’s sister website, has developed a new model for forecasting trends in polysilicon consumption by the solar industry. This article analyzes how, based on this new model, the industry’s use of polysilicon will dip below 4 grams per watt by the end of this year.

Volume production of customized organic photovoltaics

By Sri Vishnu Subramaniam; Grzegorz Andrzej Potoczny; Tobias Sauermann, OPVIUS GmbH, Kitzingen, Germany

To realize power generation everywhere, customers and designers are eager for PV solutions offering total design freedom for seamless integration into everyday life. This trend becomes even more important if the ‘mega city’ development is taken into account: more and more people will live in city environments in the future while classical PV technologies do not offer proper solutions for this context.

Top 10 module suppliers in 2017

By Finlay Colville, Head of Market Research, Solar Media

Following an extensive research process, we can now reveal the top 10 module suppliers (by shipment volumes) for the calendar year 2017. The final listing – and the underlying numbers – confirms the trends of recent years and the continued dominance of our self-penned ‘Silicon Module Super League’ (SMSL) group.

PV manufacturing capacity expansion announcement plans and analysis for 2017

By Mark Osborne, Senior news editor, Photovoltaics International

PV manufacturing capacity expansion announcements in 2017 far exceeded the three preceding years, despite the significant slowdown in new plans in the third quarter. The year was dominated by c-Si solar cell expansion plans and the return of CdTe and CIGS thin-film activity – the highest seen in many years. This quarterly report reviews the fourth quarter activity as well offering a full-year review and analysis of a record year across all segments of upstream manufacturing.

ECN’s IBC solar cells in mass production environment: rise of a competitive back-contact module concept

By Antonius R. Burgers; Ilkay Cesar; Nicolas Guillevin; Arthur W. Weeber; Jan M. Kroon, ECN Solar Energy, Petten, The Netherlands

We present an n-type bifacial IBC solar cell that uses a simple process comparable to our industrially proven n-type cell process for conventional H-grid front- and rear-contacted n-PERT cells. The process is based on tube diffusion and a simultaneous single-step screen-print of the contacts to both polarities, and has been demonstrated on an industrial line at pilot scale.