Trends in solar module production

By Hans-Joachim Bender

In 2005, Robert Bürkle's research and development team began to examine the lamination process and the materials used in solar module production. The company was aware that a multi-opening lamination line would be the way to go for high-volume solar module production, in order to meet the high capacity requirements and the need for reduced production cost per module.

Bürkle had the experience and know-how necessary to build a high-volume multi-opening lamination line for solar module encapsulation due to its experience in building multi-opening lamination lines for other industries. In 2007, after two years of research and development, the company presented the Ypsator at the photovoltaic show in Milan.

With this lamination line, high volume production can be realized on a small footprint. Its multi-opening lamination systems can be adjusted to customers' capacity requirements by changing the number of openings. Using steel heating platens in combination with thermal oil heating systems, Bürkle lamination lines ensure a homogeneous temperature distribution over the entire useful lamination area. Depending on their size, two, three or four solar modules can be laminated per opening, or up to 40 modules per cycle can be processed with a 10-opening Ypsator line.

Lamination lines

Bürkle has supplied and commissioned 20 multi-opening lamination lines since the market launch at the end of 2007. This corresponds to the capacity of more than 80 traditional single-opening laminators.

In addition to the Ypsator multi-opening lamination line, Bürkle also offers the e.a.sy-Lam single-opening lamination line for module encapsulation. Since the beginning of 2008, nearly 20 lines have been supplied to solar module manufacturers. Bürkle has supplied laminating lines for crystalline cell solar modules and thin film (glass-glass) solar modules to module manufacturers in Europe, North America and Asia.

New processes

The company has also developed the 3-Step Process, which revolutionised the lamination process. It permits a higher production capacity with considerably reduced cycle times, as well as the production of new materials due to the high flexibility of the concept and the selection of parameters.

The 3-Step Process is available for crystalline solar cell modules as well as thin film (glass-glass) solar modules. For crystalline solar modules, two vacuum laminators are arranged after each other, followed by a cooling unit. For glass-glass thin film solar modules, the first step is a vacuum laminator followed by a hydraulic hot press and a cooling press. In the hydraulic hot press, the glass-glass modules are heated under pressure from both sides. In the cooling press, the modules are cooled down under pressure from both sides.

Due to the uniform heating and cooling from both sides, the internal stress of the laminated modules is reduced, which minimizes glass breakage. The symmetric heating in the second step provides laminated solar modules with uniform and high gel-content. The modules can be immediately processed, due to the uniform temperature of the solar module after cooling.

Additional products

The German manufacturer has enlarged its production portfolio and offers transport and handling equipment and intermediate storage units/buffer racks, as well as complete lines for the so-called back-end of the module production for thin-film technology. This comprises crucial components from its own development and production such as foil uncoiling and foil lay-up, pairing and the automatic setting of junction boxes - just to name a few components.

For more information, please visit www.buerkle-gmbh.com

Hans-Joachim Bender is Managing Director, Managing Partner and Speaker of the Management Board for Robert Bürkle GmbH, Freudenstadt. Bender studied mechanical engineering and was Factory Manager of Degussa (now called Evonik) and Managing Director of Badische Maschinenfabrik Durlach GmbH (BMD) before coming to Bürkle. In October 2009 he was awarded the enterprise medal of Baden-Württemberg.