Heat transfer and control of the temperature field are important in the production of silicon solar cell wafers. Present work focuses on the first steps of the production chain, i.e. crystallization and wafering. For the crystallization process, control of heat transfer is crucial for the ingot quality in terms of grain structure, impurity distribution, particle formation, and ingot stresses. Heat transfer is also important during subsequent processes, in particular the wire sawing of the silicon blocks into wafers. The paper emphasises the role of heat transfer and explains the consequences for these processes. Examples from experimental trials and measurements are combined with models and simulation methods.
PV manufacturers can quickly reduce their costs, and increase their yields, by using SEMI standards that were originally designed to help semiconductor fabs deal with power glitches and power costs. SEMI, the global industry association serving the manufacturing supply chains for the microelectronic, display and photovoltaic industries, has two well-established electric power standards that could prove especially useful for PV manufacturing: SEMI F47, which helps equipment deal with power disturbances, and SEMI E3, which helps users understand how much electric power is used in their recipes. This paper provides a method of lowering costs and increasing yield by applying these standards in the PV manufacturing industry.
Chemical stoichiometry along with depth profiling and metallic contamination is of considerable interest for photovoltaic thin films. Conversion efficiency can be affected for example if primary components, e.g. Cd and Te, are not present at proper ratios. Moreover, amorphous silicon can vary substantially between sources and deposition technique, and qualitative comparison of trace metallic contaminants may not be sufficient to ensure final thin-film quality. This discussion presents data from atomic emission and mass spectrometry techniques that quantitatively and accurately describe both bulk and trace elemental compositions in photovoltaic materials, various thin-film matrices, and the final thin-film cell and module.
This paper, the second in a series covering cost of ownership studies for photovoltaics [1], examines the need for saw damage removal and the follow-on processes of precleaning, texturization, and cleaning. The process considerations for wet and plasma approaches are further discussed before taking a detailed look at texturization using random pyramid formation. The paper will conclude with a view of current and future wet process techniques and a cost of ownership case study using Akrion Systems’ GAMA-Solar as an example.
Solar enterprises will each be faced with the occasional surplus or lack of solar modules in their lifetimes. In these instances, it is useful to adjust these stock levels at short notice, thus creating a spot market. Spot markets serve the short-term trade of different products, where the seller is able to permanently or temporarily offset surplus, while buyers are able to access attractive offers on surplus stocks and supplement existing supply arrangements as a last resort.
The current feed-in tariff (FiT) scheme in Italy has so far resulted in a total installed PV capacity just above 600MWp. The majority of those installations (77%) are building-adapted (BAPV) or building-integrated (BIPV) thanks to the higher incentives provided compared to non-integrated ground-mounted plants. Moreover, there are special premiums on top of the basic FiT, such as when asbestos roofings are replaced with PV modules. On the one hand, this makes the Italian PV market very attractive for those players specialized in roof applications, while on the other, it represents an opportunity and a strong motivation for both the installers and the manufacturers to explore innovative and standardized BIPV solutions and materials. Will this trend continue in the years to come?
With growth in 2009 suffering from recession and an ongoing credit crunch, this paper presents a review of the key trends in cell and module manufacture for the crystalline silicon (c-Si) PV module market. The c-Si segment remains the largest segment, and is competing effectively with less mature thin-film technologies. PV is still a largely uneconomic way to generate power, and requires subsidy to maintain sales volume and growth. While subsidies exist, the industry treads the narrow path of growing at a healthy clip, developing robust technology and business models, and mapping paths to profitable business without subsidies once PV installations become economically viable.
The uttermost importance of the regulation framework to trigger the development of a PV market has been recognized these last years in many European countries. For policymakers today one of the key questions is making the best choice to initiate and stimulate PV markets. In the aftermath of the financial crisis, EPIA has launched the PV Observatory initiative. It aims at analyzing the current state of regulatory frameworks in a set of countries, starting with the main European PV markets.
Development of fine-line crystalline silicon solar cells is a potential direction for application of high-efficiency and low-cost solar cells in the industry. Fine-line mask-free metallization offers huge potential to increase cell efficiency by reducing metal shadowing losses and surface recombination losses. At China Sunergy, three promising approaches for fine-line crystalline silicon solar cells are currently undergoing research, including processes such as laser doping selective emitter (LDSE) technology, inkjet or aerosol jet printing of metal paste and upgraded screen-printing technology. This paper presents the basic investigations of these three manufacturing technologies, singling out the technology that presents the most potential for further application.
An improved understanding of multicrystalline wafer quality can explain variations in cell performance across multicrystalline silicon blocks. Infrared scanning can detect precipitates in a silicon block, while photoluminescence combined with defect etching can reveal needle-like precipitates along the grain boundaries. Such precipitates typically lead to reduced shunt resistance. Crystallographic defects that lower the current collection and the final cell efficiency can also be identified. Understanding the influence of these defects is important for the development of a crystallisation technology that results in a substantially better cell efficiency. The use of the improved material quality in an innovative cell and module technology have led to the world record module efficiency of 17%. This paper will illustrate one example of how an improved understanding of multicrystalline wafer quality can explain the variations in cell performance.
