The Italian PV market is poised to become the leading market worldwide. However the recent GSE estimates have revealed unexpected volumes installed in 2010. This may lead to an adjustment of the feed-in tariff (FiT) level in the course of this year. GIFI (the Italian PV industry association) is preparing the field for a proposal to make the market development more sustainable, long-lasting and to upgrade the 2020 target.
In 2006, Conergy AG started construction on one of the most advanced solar factories in the world in Frankfurt (Oder). On 35,000 square metres, a fully integrated and fully-automated wafer, cell and module production facility was created – all under one roof. Since 2008, production has been running at full speed and every day more than 3,000 premium modules roll out of the factory. This paper outlines the Manufacturing Execution System (MES) process put in place by Conergy during the planning phase of the factory, to monitor and control the complex and merging production processes.
Over the past two years the solar industry has shown itself to be incredibly resilient to general economic crisis. Supported by cost-cutting and efficiency improvements, the PV industry managed to achieve a growth rate of 120%, or 16.2GW, of newly installed capacity in 2010. Although individual companies are feeling the strong price and margin pressure and intensifying competition, the large, international and vertically-integrated companies are surviving. At least eight new PV markets with a potential annual capacity of 500MW are expected to be added over the next two years. The PV industry will therefore acquire the stability and political autonomy it needs to be able to grow unimpeded and to enter new dimensions. There might also be further tailwind for the PV industry from the catastrophic nuclear crisis in Japan.
Supporting a smooth application of new wafer materials and handling equipment into photovoltaic mass production requires extensive testing of new wafers and equipments under a range of potential operating conditions. The management of such experiments, both in laboratory and production environments, demands the integration and management of a multitude of differing information. This includes static data-like equipment, specifications and experiment settings, online machine data regarding process signal and events – but also unstructured human knowledge, which is available in manual and test reports. To efficiently deal with these kind of complex environments, knowledge management techniques have proven to be a promising approach in various industrial applications. This paper depicts, by means of a photovoltaic wafer-testing platform at Fraunhofer IPA, how the application of automation systems and knowledge management techniques leads to more effective experiment management. More precisely, the gathered knowledge from the wider range of information included in the analysis of experiments can be re-used during future experiments and the manual effort is significantly reduced.
A growing number of thin-film photovoltaic module producers are either trying to keep up with the current cost leader or aiming to differentiate on product design. Calyxo is dedicated to both keeping the pace in the US$0.50/Wp race and introducing new product generations, therefore delivering more value to the customer. We have tried to improve the methodology and approaches for knowledge building in the individual process steps, by learning the relevant interactions between them, as well as ramping volume and lowering manufacturing cost in the first production line. Developing and building the deposition equipment suited to the high process temperatures of approximately 1000°C at atmospheric pressure took some time, but the technology itself now enables Calyxo to benefit from significant cost savings both on capital investment and operational cost – compared to some well-known vacuum deposition methods. Besides the continuous decrease in manufacturing costs, even early on in building the manufacturing capacity, the ability to design the product itself according to the needs of the customers proved itself to be a decisive factor in ensuring competitiveness. This paper aims to give an insight into some of the basic design features of a new product generation and how the so-called new CX3 product will generate more watts by improved performance: delivering better customer value by decreased voltage to save on BOS costs and ensuring further increased field durability through an optimized package design.
Phosphorus dopant pastes are an attractive alternative to the conventional phosphorus oxychloride (POCl3) dopant source for emitter processing in solar cells, as they allow the fabrication of selective emitters on an industrial scale. In this paper it is demonstrated that single-sided uniform screen-printed emitters, processed with phosphorus dopant pastes, can getter multicrystalline silicon (mc-Si) wafers more effectively than conventional double-sided uniform POCl3 emitters. This result is confirmed by minority carrier lifetime measurements with the quasi-stead-state photoconductance (QSSPC) method. Solar cells with selective emitters were processed using phosphorus dopant pastes on mc-Si wafers and were subsequently characterized. The current-voltage (I-V) results are improved compared to uniform POCl3 emitter solar cells and an increased internal quantum efficiency (IQE) for selective emitter solar cells is demonstrated.
Upgraded metallurgical-grade silicon (UMG-Si), once looked on as a cost-effective and energy-efficient alternative to Si produced via the Siemens route, has experienced a severe regression of late. This has been caused both by the market conditions and by specific physical properties of these materials. Meanwhile, the qualities and the rated influence of negative physical effects have changed partially. Hopes are again rising that these materials, which have to be compensated to meet the desired net doping specifications, might achieve an economical breakthrough instead of long-dreaded low breakdown voltages. In the following paper, we summarize a few of our results on multicrystalline UMG silicon as well as results published by other research groups in the last few years.
The 12th Edition was published in May 2011. Highlights from this edition include Conergy’s in-depth study of MES in PV facilities; University of Konstanz heralds the return of UMG-Si; RWTH Aachen University details the gettering options available for selective emitters; TU Delft presents an overview of breakage issues for silicon wafers and cells; and the University of Toledo outlines the benefits of RTSE in polarized light metroscopy.
Technology computer-aided design (TCAD) is pervasive throughout research, development and manufacturing in the semiconductor industry. It allows very low-cost evaluation of process options and competing technologies, guides process development and transfer to production and supports more efficient process improvement with minimal down time in the factory environment. This paper reviews the use of TCAD in the semiconductor industry and shows, with some illustrative examples, its important enabling role for the PV industry.
Reduction of silicon wafer thickness without increasing the wafer’s strength can lead to a high fracture rate during subsequent handling and processing steps. The cracking of solar cells has become one of the major sources of solar module failure and rejection. Hence, it is important to evaluate the mechanical strength of silicon solar wafers and influencing factors. The purpose of this work is to understand the fracture behaviour of multicrystalline silicon wafers and to obtain information regarding the fracture of solar wafers and solar cells. The effects on silicon wafer strength of saw damage and of grain size, boundaries and triple junctions are investigated, while the effects of surface roughness and the damage layer removal process are also considered. Significant changes in fracture strength are found as a result of different silicon wafer crystallinity and surface roughness. Results indicate that fracture strength of a processed silicon wafer is mainly affected by the following factors: the saw-damage layer thickness, surface roughness, cracks/ defects at the edges and the number of grain boundaries – which all serve as possible crack initiation points. The effects of metallization paste type and firing conditions on the strength of solar cells are also considered, with findings indicating that the aluminium paste type and firing conditions influence the strength of solar cells.
