Photovoltaics International Papers

This paper outlines how a blend of physics-based analysis and statistical data science methods can aid continuous improvement and yield optimization in high-volume solar cell fabrication.

PV manufacturing capacity expansion announcements in 2019 were a stark contrast to 2018, when major policy changes in China impacted the upstream supply chain. This paper looks in detail at not only a significant recovery in capacity expansions throughout the year but also new trends in the capacity scale of announcements and a marked shift in wafer sizes and cell technology.

Organic/inorganic lead halide perovskite solar cells (PSCs) have received global attention because of their excellent photovoltaic performance and ease of fabrication. PSC’s have reached over 24% power conversion efficiency demonstrating that the lead halide perovskites are the most promising class of materials for next-generation thin-film photovoltaics. The unprecedented increase in the device performance from 3.8% to 24% in less than 10 years is mostly due to compositional engineering of mixed cations, and anions, as well as improved processing protocols has made PSC the fastest development of a new material in the PV field. Though the efficiencies on Lab scale are staggering, the full potential of this burgeoning technology cannot be realized without addressing the following challenges: fighting the degradation of the material is the highest focus for the moment and has several fronts for improvements including within larger scale cells or modules. The other main challenge of the new class of material is the toxicity risks due to the presence of lead. The research community is actively working on the mitigation and reduction of the associated risks. The exceptional properties of this material combined alongside its inherent relative lower costs have already triggered the interests of industries and start-up worldwide while on a European regional level, EPKI for European Perovskite Initiative was formed gathering all the significant players in the field.

Photovoltaics International’s annual analysis of PV manufacturers, research and development (R&D) spending in 2018 includes 21 companies that were public listed on various stock exchanges around the world. R&D spending data was taken from audited annual financial reports and converted to US dollars at the time of the reports being published. The analysis in this 2018 report is intended to provide a good representation of global R&D spending trends in the PV wafer, cell and module segments of the upstream solar market.

This paper reports on the latest advances in passivated emitter and rear cell (PERC)-based shingled solar cell activities at Fraunhofer ISE. The approach taken is to fabricate 6" host wafers from Czochralski-grown silicon and separate them after metallization and contact firing into bifacial p-type shingled passivated edge, emitter and rear (pSPEER) solar cells.

Heterojunction technology is currently a hot topic actively discussed in the silicon PV community. Hevel recently became one of the first companies to adopt its old micromorph module line for manufacturing high-efficiency silicon heterojunction (SHJ) solar cells and modules. On the basis of Hevel’s own experience, this paper looks at all the production steps involved, from wafer texturing through to final module assembly.

This paper presents the calibration of solar cells, in accordance with the IEC 60904 standards, carried out at the solar cell calibration laboratory of the Calibration and Test Center (CalTeC) at the Institute of Solar Energy Research Hamelin (ISFH). For the calibration of a solar cell, the cell area, the spectral responsivity (SR) and the current–voltage (I–V) curve have to be determined. The I–V curve then yields the characteristic parameters, including the power conversion efficiency, fill factor, short-circuit current and opencircuit voltage. The required measurement facilities and contacting stages are explained in detail; in addition, the measurement procedures are introduced. The precision and accuracy of the resulting characteristic parameters and curves are demonstrated by recent intercomparisons between different international calibration laboratories.

Passivated emitter and rear cell (PERC) solar cell design is the industry standard for high-volume solar cell manufacturing today. The next challenge for the PV industry is to find a low-cost cell upgrade technology platform that can be easily retrofitted in existing production lines to modify the front side and enhance the rear. The monoPolyTM technology platform, developed at SERIS together with its strategic industry partners, offers an attractive solution and paves the way for the adoption of passivating contacts in large-scale manufacturing. This platform requires only one tool upgrade for most PERC/T production lines, has one less process step than a standard PERC production process, and yields a +1%abs. efficiency boost over a standard PERC process. The authors believe that monoPoly will enable the PV industry to mass produce cells with efficiencies exceeding 24% in their existing lines in the near future.

The PV industry is undergoing rapid technology changes that have been driven by the well-documented swift adoption of monocrystalline wafers. Less well understood, however, is that within this wafer technology transition comes a shift to larger wafer sizes, and this includes p-type and n-type mono-Si wafers.

This paper explains how these modern production concepts are implemented in ISC’s lab, and details the plans for their utilization in future production sites, with illustrations of the key benefits in practice. With these modern manufacturing concepts, it will even be possible to bring future c-Si PV production back to the EU with the choice of an appropriate cell concept (high efficiency but proven technology, e.g. interdigitated back-contact (IBC) cells, such as ZEBRA) and a sound business plan.