High productivity in-line screen printing system for crystalline solar cell manufacturing
To develop a high performance in-line screen-printing system, the NPC Group defined an appropriate benchmark for characterizing the industrial efficiency of the operation and carried out a full analysis of the factors affecting this benchmark. A screen-printing system design based on careful cost analysis can produce a machine with a high effective throughput and low cell breakage. As a result, NPC is now offering advanced in-line, high precision systems to the photovoltaic industry. Future design changes results in machine speeds of 1,600 wafers per hour at a breakage below 0.5% for the three prints typical of the current cell manufacturing process.
Processing of crystalline silicon solar cells in high throughput production tools
The contribution of breakage-induced yield losses in solar cell and module manufacturing costs is well understood. Breakage data and information about the solutions implemented by cell manufacturers have a proprietary nature and are much less well known. The emergence of equipment manufacturers serving many customers is enabling solutions that are of common interest to the industry to become better known. In this paper we discuss the cell handling requirements of crystalline silicon solar cell manufacturers and present data obtained with two machines designed and manufactured by the NPC Group and used in cell testing and module assembly operations. On this basis, we propose topics where industry collaboration with the research community could result in advantages for all cell manufacturers.
Evolution of carbide precipitates in Hastelloy N joints during welding and post weld heat treatment
Abstract The effects of welding and post weld heat treatment (PWHT) on the morphology, composition and lattice parameter of the precipitates in the welding joints of Hastelloy N alloy have been investigated. Joint samples were prepared using a gas tungsten arc welding process with ERNiMo-2 fillers, and then solid-solution treated at 1100 °C for 20 min. After welding, eutectic M6C carbides can be observed in the heat affected zones (HAZ) and weld zones (WZ). These eutectic M6C carbides become spheroidized during the following PWHT. The concentration of Si decreases during the transformation from the primary ones to eutectic ones, and then increases during the spheroidizing process. The total concentration of Si + Cr in M6C carbides remains stable during welding and PWHT. At the same time, the heat leads to the outward diffusion of Mo from the M6C carbides, which results in a decrease of the lattice parameter.