Among the various thin-film solar module options available, CIGS is especially interesting as it exhibits the highest efficiency potential. These chalcopyrite-based solar cells are manufactured on glass or flexible substrates using various thin-film coating methods for each layer. The central CIGS absorber layer is deposited by co-evaporation, selenization of elemental layers, and other methods. In order to achieve highest quality and reproducibility, the absorber properties must be properly monitored and characterized. In this contribution we shed some light on the most important analysis methods used for CIGS solar cell research, development, and production such as x-ray fluorescence, surface analysis, and Raman spectroscopy.
SolarWorld USA’s two main manufacturing facilities in Camarillo, CA, and Hillsboro, OR, represent the past, present, and future of crystalline-silicon solar photovoltaic manufacturing in the United States. The Southern California site, which sits in a small industrial park across from a verdant expanse of strawberry fields, was home to one of the world’s first (and at one time the largest) solar factories in the late 1970s, a historic campus that has changed corporate hands several times, from Arco Solar to Siemens Solar (1990) to Shell Solar (2001) and finally to SolarWorld (2006) over the three decades since its inception. This paper provides a look inside the factory doors.
Power quality and reliability are two very important factors in electrical power supply, particularly for specific branches of industry. Multifunctional PV battery systems can improve power quality, substitute uninterruptible power supply systems, and can offer additional services such as energy management and peak shaving. This article presents the results of an analysis of possible services under current German conditions and the measurement results of laboratory tests and a pilot demonstration.
Armed with the aim of generating a knowledge base on CPV technology, ISFOC has installed 1.4MW of CPV and is executing up to a total of 3MW of power plants incorporating seven different technologies, all scheduled for completion in 2009. These pilot plants are being established to assist the industry in the setting up of pilot production lines and to obtain very valuable information such as reliability, suitability and production [1]. Rating measurement approaches have been proposed by ISFOC, but there remains a need for an international standard that is accepted by the CPV community. This paper presents ISFOC’s proposed standards set and outlines the methodology adopted by the company in this respect.
The encapsulation of solar cells is one of the most enduring ‘traditional’ process steps in the fabrication of a photovoltaic module. The need to protect the delicate semiconductor active solar cell with protective material to ensure long-term operation remains a critical step in the module assembly process. However, continued development of the lamination process and materials used for encapsulation are required to meet increased demands of 25-year guaranteed module operation in the field, shorter cycle-times and lower production costs. In this two-part article, we look at the challenges these and other factors are having on the lamination process, the equipment required and the developments taking place to meet module manufacturers’ requirements now and in the future.
Although much of the emphasis of Part 1 of this paper (in Photovoltaics International ed. 5) focused on material quality issues and attention to detail on process control, high-volume manufacturing requires a concerted effort to constantly improve productivity of the lamination process and in turn the productivity of the total module manufacturing line. Such is the competitive landscape that greater attention to these factors is becoming a key differentiator for both equipment suppliers and module manufacturers. In this, the second part of the lamination process focus, we will look closely at the dynamics impacting module prices and the developments being undertaken to improve cycle-times of the lamination process, overall productivity and optimization as well as costs to ensure future competitiveness.
This article will look at what trends can be gleaned from patent application publication figures of the past decade in the sector of PV technology. The study looks at the number of patent applications in PV technology published worldwide between 1999 and 2008. The data will show in which regions and countries patent protection is being sought. The figures are taken from patent documentation databases developed by the European Patent Office (EPO) and Japan Patent Office or databases used worldwide and available at the EPO, and they are retrieved mostly using patent classification schemes. The article also provides a brief overview of the role of the EPO and what companies, researchers and individual inventors should keep in mind when applying for a European patent.
Laser doping is discussed often in relation to silicon photovoltaic cell efficiency enhancement. However, the specific use of lasers for dopant diffusion falls within a broader category of ‘Laser-Assisted Selective Emitters’. Understanding the benefits enabled by laser tools here is important not just in explaining what laser doping is, but why laser processing features in most selective emitter concepts.
With the ever-growing challenge of remaining financially viable in today’s economic climate, some companies in the PV industry are adapting and applying the structures and principals of project finance to the photovoltaic assets. The purpose of project finance is to create a business structure which brings together multiple entities, aligns their interests, and allocates the project’s inputs and outputs (i.e. risks and rewards) in such a way that the overall benefits derived from the project are maximized.
The process of wafering silicon bricks into wafers represents about 20% of the entire production cost of crystalline silicon solar cells. In this paper, the basic principles and challenges of the wafering process are discussed. The multi-wire sawing technique used to manufacture wafers for crystalline silicon solar cells, with the reduction of kerf loss currently representing about 50% of the silicon, presents a major challenge for further research efforts. Another relevant field of research is the reduction of wafer thickness in order to obtain more wafers per millimetre of brick length. The last subject that is addressed in this paper is the general optimization of the wafer surface and geometry, as the multi-wire saw cutting process influences the mechanical properties of the wafers and can have further effects on subsequent process steps.
