Flexibility Counts

Fig. 1: Cross-contacts are soldered using an inductive process. This guarantees top-quality connections.

In response to the number of orders and requests received by the company PV Products (PVP) based in the Styrian town of Wies in Austria, management decided not only to produce conventional glass-film photovoltaic modules but also to invest in manufacturing equipment for producing high-quality glass-glass solar modules. Standard high-efficiency modules are made from 156 × 156 mm mono- and polycrystalline silicon cells in three product lines with 48, 60, or 72 cells. The company is also flexible about supplying solar modules in special dimensions, various formats, and different colors. Thus, PVP manufactures glass-glass modules in any size up to 3500 × 2100 mm using either laminated safety glass (LSG) or LSG-insulating glass. Furthermore, round and triangular formats can also be produced. The glass solar elements are laminated with polyvinyl butyral (PVB) film which is available in a wide range of colors. This enables individual color requirements to be met.

High demands on the production line

Cost-effective implementation of  a high level of flexibility called for a partially automated production line exactly matching the PVP’s requirements. It also had to be possible to rapidly reset the line for production of different-sized modules. “We spoke to a number of plant manufacturers and finally opted to work together with ACI-ecotec. The decision to collaborate with the company from the Black Forest was partly based on the company’s excellent consulting service and partly on the concept of its S30M manufacturing system. The human factor also played an important role and enabled us to work together in a highly constructive manner”, stated Karl Kürbisch, one of the managing directors of PVP.
In its present state, the S30M production line can manufacture solar modules fully automatically with a capacity of 30 MW per year. It also possesses addirional manufacturing units which enable 5 MW to be produced. Integration of a second stringer as well as additional robots for cross-contacting has already been taken into account in the plant design, thus enabling production capacity to be increased to around 60 MW per year.

Combined line and customized production

Fig. 3: A handling system which can be rapidly adapted to various string lengths ensures accurate handover to the robot.

The first station in the manufacturing system is the glass-cleaning unit which is fitted with a crane. On completion of the automatic cleaning and drying processes, the first encapsulation film is applied manually. Special formats are then diverted to flexible manufacturing units while standard glass panels continue on to the lay-up station. At the same time, solar cells are singularized in the stringer, checked by a camera system, positioned correctly, and busbars applied and soldered. Depending on the module, two or three busbars are applied. A clamping system holds the busbars accurately in position until they are soldered. This ensures accurate lines and a flawless appearance, even in the case of extremely long strings.
A handling system positions the completed strings so that they can be picked up by a robot. Before placing the strings on the glass panels, the robot first passes them through a testing unit to check the soldered connections. The busbars are then shortened automatically to the correct length. A particular feature of the lay-up station is a special drawer system. “It enables us to produce strings in advance during work…”

Facts for Decision Makers

Cost-effective manufacturing

• Cost-effective implementation of a high level of flexibility requires a partially automated production line.
• This ensures flexibility in the supply of solar modules in special dimensions, various formats, and different colors.
• The S30M production line can manufacture solar modules fully automatically with a capacity of 30 MW per year. It also possesses additional manufacturing units which enable 5 MW to be produced.

Fig. 2: Designed for a three-step process, the laminator also contributes towards the high capacity of the production line. Several modules are grouped together for batchwise lamination.