Portable Measuring Arm Ensures the Performance of Photovoltaic Modules
AT&S - Austria
AT&S is one of the world’s leading suppliers of highquality circuit boards. These boards carry and provide the electrical connection to mounted components in practically every electronic device. AT&S products are mainly used in portable devices such as smartphones and tablet PCs, in automobiles and the fields of industrial and biomedical technology.
The Solder Ribbon Dilemma
AT&S exploits the know-how gained from making circuit boards to manufacture photovoltaic modules using a new connection technology. Solar systems consist of individual cells connected together to form a solar module. In conventional modules, the cells are connected by solder ribbons to conduct the current. The manufacturers of these modules either use relatively thick ribbons (which leads to greater shadowing of the active cell surface) or very thin ribbons (which cannot carry as much current). In either case, these solar modules are less efficient because the calculation is based on the sum of the theoretical output of each cell. Mario Egger, Photovoltaics Department Manager at AT&S, says: “The use of these connecting ribbons results in efficiency losses of up to 2% per module. The cumulative loss for a large installation over decades is immense.”
Backsheet Foils Mean More Output
AT&S has completely avoided the connecting ribbon dilemma in its photovoltaic products. At its factory in Leoben, the company manufactures conducting foils for providing the contact on the back of the solar modules. Various coatings on the conducting surface insulate and strengthen the foil. Thirty-one contacts, which must coincide with precisely defined points on the back of the solar cells, are left uncoated on each foil. Mario Egger explains the advantages of this form of construction: “The backsheet foil minimises the efficiency loss of the solar module – which is a factor of 10 less than with soldering bands.”
ROMER Absolute Arm: Simple Operation, Reliable Measurements
The AT&S technicians check whether all the contacts are in the right positions using a Hexagon Metrology portable measuring arm, the ROMER Absolute Arm. With the measuring arm, they determine the precise positions of 52 reference points per foil, from which they can judge the success of the coating operation. If the reference points are in the correct positions, then so are the contact points. Process Engineer Stefan Portner is one of the users of the ROMER Arm. He has learned to appreciate the advantages of the portable coordinate measuring machine: “The ROMER Arm is very flexible and easy to operate. We have also established that the measured values are very reliable and their accuracy has remained stable over time. We tested the reproducibility of the results with various colleagues – the measuring arm is extremely dependable.” Around 100 foils are inspected in this way every month. AT&S send the test reports with the measured foils to partners and customers.
Transparency Transforms into Trust
Mario Egger sums it up: “The ROMER Absolute Arm is highly suitable for inspecting the backsheet foils. The reliability of the measurements creates transparency in our relationship with our customers, who also benefit from the excellent quality of the foils. With these measurements, we secure not only the quality of our manufacturing processes but also the trust of our customers.”