Optical Inspection for the Field of Thin-Film Solar

Transcription

1 Top quality for the photovoltaic industry Optical Inspection for the Field of Thin-Film Solar Thin-film solar cells are playing an increasingly important role in the photovoltaic industry. Even though the availability of the materials used for these kinds of solar cells is practically unlimited, the processing steps during the manufacturing of solar cells are still quite complicated and require that the quality process be monitored one hundred percent of the time. This is why it is a good idea to make use of a camera-based in-line inspection system after each important production segment so that it is assured that only completely inspected parts that have been found to be ok continue on to the next processing step. In doing so, the fully automated inspection with 100% defect recognition combined with tools for processing optimization will maximize the rate of return of the production equipment. Thin-film solar technology is playing an increasingly more important role when it comes to manufacturing solar cells. Solar cells or photovoltaic cells are electrical components that make use of the photoelectrical effect to convert the radiation energy of sunlight directly into electric energy. One issue that has been contributing to the growing use of this technology is the fact that the availability of the materials used, such as silicon, is practically unlimited. Solar modules are made of component parts that are harmless to the environment. The manufacturing process itself can be carried out at low temperatures. The thin-film technology makes it possible to connect Page 1

2 the solar cells to solar modules in series. This allows a simplified adaptation of the module voltage. Efficient and precise automatic inspection The latest developments in this process allow special coatings made of zinc oxide to be used for thin solar glass. These transparent and conductive layers also known as TCO increase the efficiency of photovoltaic systems by nearly 5%. The size of the glass surfaces being produced is becoming larger and in the generation 8.5 are reaching sizes of 2.2 m x 2.6 m. In the process, quality inspection requires particular attention to ensure that the high demands placed on the photovoltaic industry are met. The POWERSCAN systems by ISRA VISION offer an efficient and precise automatic inspection. These systems can be integrated into a variety of different processing steps within the process chain. Directly after the washing sequence for the solar cell raw materials and before the high-quality coating sequence, they reliably detect typical glass defects and specific defects such as shells and breakouts on the edges. Defective material can be discharged immediately and never reaches the high-quality coating process. POWERSCAN is then used directly after the coating process to inspect whether the coating was applied properly. This is typically followed by the edge processing of the solar cells, which also involves an inspection process of the corners and edges. Further steps include the scribing, chemical vapor deposition (CVD), cutting and lamination processes. Each of these steps can conclude with an inspection process so that at each step only 100% inspected merchandise arrives for further processing throughout the entire front and back end area. Page 2

3 This assures that costs for the production of thin film modules are reduced considerably. POWERSCAN can be used to inspect all of today's and the future's glass and module sizes quickly and at highest resolutions. Because of the modular systems that can easily be integrated into a variety of different production stages, every customer is supplied with a customized solution. As far as the camera modules in use are concerned, the systems are scalable, which makes it possible to satisfy any requirement. Simple, reliable and precise defect classification Because of the extremely high resolution in the µm range, even the smallest defects are detected reliably at a maximum sheet width and at highest production speeds. No other system in its class is able of inspecting material surfaces faster and more accurately. Highresolution high speed cameras provide crystal clear images of any defects and the QUICKTEACH function allows them to be categorized easily, reliably and exactly. The state-of-the-art teaching classification software processes the inspection data in real-time. QUICKTEACH allows a learning by showing process: The software needs only to be taught the products and the names of the defect types once and no expert knowledge is required. Data and images of all significant defects are stored to be analyzed at a later time and can be called up during the processes with one click of the mouse. The information collected in this way can be used for optimizing the production process. This makes it possible to ideally configure the production processes. The customers benefit from thin film solar cells of top quality. Page 3

4 Maximize the rate of return of production systems The POWERSCAN system is so flexible that it can also be used successfully in other fields of the photovoltaic industry. ISRA inspection tools, which have been considered a proven technology for a long time in many different areas, such as for inspecting optical display films, thin films or in glass inspection technology, is not only the selection of choice when it comes to quality control and process optimization in the production processes of thin-film solar, such as CIS, CIGS, CSG and CdTe, and also of solar wafers for inspecting defects in the coating, structure, edges and other typical glass defects. It is also the product of choice for inspecting solar modules (inspecting for completeness, position, size, geometry and glass defects) and cover glass (inspecting for glass and edge defects as well as size/dimension errors). The inspection systems increase processing reliability and productivity. The fully automated inspection combined with 100% defect recognition, in addition to tools for processing optimization, maximizes the rate of return of production equipment and ensures that its users are ahead of their competition in a global market. Page 4

5 Picture 1: Thin_film_1.jpg Best quality higher energy efficiency: Thin-film solar modules in use Picture 2: Thin_film_2.jpg To be on the winning side: Exact 100% inspection at all processing stages in thin-film photovoltaic module production from front to back end - assures higher yield, higher energy efficiency, and better customer acceptance Page 5

6 Picture 3: Thin_Film_3.jpg Typical defect, reliably detected by POWERSCAN: pinholes Picture 4: Thin_Film_4.jpg A big problem for quality, not for POWERSCAN: patches Page 6