New technology of laser printing transferable from BASF's and companies Schmid

Contactless printing and related silver pastes increase the efficiency of production wafers. Innovative technology will be first presented at the 24th European exhibition and conference on photovoltaic solar energy in Hamburg. Conclusion technology on the market is planned for early 2010

Currently, the metallization process is mostly used screen printing. The system of printing and pastes developed by BASF and Schmid, based on non-contact laser technology process and not only provides customers the benefits of exploitation but also increases the efficiency of solar cells. So, eg using the new technology reduces break wires, increasing productivity and there is the possibility of processing solar cells with thickness less than 180 microns. Besides, pasta BASF is extremely eco-friendly, because it does not contain lead in its composition. Also available are silver and aluminum paste, water-based v. e. solvent, application of these pastes will contribute to significant improvements in production, particularly in relation to the manufacture of photocells.

Concern BASF, with years of experience in the production of metal-based pastes for different applications, began development of a silver paste for the PV industry in 2005. "We wanted to meet the demands of industry in this segment, and not only offer "regular" silver paste, not contain lead, but also to try to improve the process of metallization, - Said Dr. Frank Kleine Eger, Project Manager BASF for the production of silver paste. As a result, the idea of developing the technology of laser printing, and specially designed for the pasta, solvent. Soon BASF find a suitable partner in the company aurentum Innovationstechnologie GmbH, located in the city of Mainz (Germany), the company developed a process of non-contact laser printing with the help of special pastes, not contain lead.

Order to have the opportunity to test the technology and paste on an industrial scale, in late 2008, BASF signed an agreement on a joint project with the company Schmid Group, one of the world's largest manufacturers of equipment for manufacturing photovoltaic cells. "In the face of the company Schmid, we were able to get one of the most innovative partners having a great experience not only in production equipment, but also in the solar industry, - Said Dr. Eger. - "Only through joint efforts we were able to so quickly and flexibly to implement our idea in a real, really a production mechanism.

Laser printer for printing transferable LTP PV 1500 was developed by Schmid Group to fully replace the existing technology of screen printing. It can be used for the application of aluminum and aluminum-silver coating on the back (inside) of photocells and the silver coating on its front (outer) part. The system can be integrated into existing production lines, it is suitable for solar cells of all types and sizes. There are plans to unite the technical processes of printing on the inside and outside cells. Printer LTP has a capacity of 1,500 wafers per hour, and he absolutely exclude any contact prevent any possible mechanical influence on the plate. Plate, which will be produced print previously placed in the printer, fixed on the vacuum conveyor and then passed through a laser. Laser beam separates metalliziruyuschuyu pasta with a film carrier and transfers it to the plate. Pasta on the film continuously and cyclically replaced. Built-in feeder to meter ink viscosity allows the use of pastes with different compositions. Printing is carried out in digital mode, that gives the possibility to work with any patterns as well as production individually printed plates.

Since 2010 BASF will produce customized pastes for the metallization of mono-and polycrystalline solar cells, specifically for the new technology LTP; they are also suitable for use in conventional screen printing. The assortment will be included as a silver based paste for printing on the front side, and aluminum-based pastes for printing on the reverse side of the plates.

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