Design and application of a linear acceleration test setup for defect diagnostics in high-throughput transportation systems

• Main Authors: Großer, Stephan, Schak, Matthias, Hagendorf, Christian
• Format: Conference Proceeding
• Language: English
• Subjects: Abrasion; Belt conveyors; Damage; Design defects; Dynamic loads; High acceleration; Metallizing; Photovoltaic cells; Production lines; Silicon; Silicon wafers; Solar cells; Transportation systems; Velocity distribution; Wafers
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0141820

The expected tera-Watt PV market leads to the need of large production capacities above 10 GWp/a. One rising challenge for new generations of cell production lines is the improvement of high-throughput transport technologies [1]. Silicon wafer and solar cells must be moved and transferred in or between production tools with high acceleration and velocities to ascertain that no delay or bottle neck is generated by the transport for upcoming GWp/a facilities. Surfaces of wafers and solar cells are often affected by handling-induced defects. Highly sensitive passivation and metallization structures may be damaged by the enhanced dynamic loads acting at the interface between high-speed band-conveyor and inert sample mass, accompanied by sample displacement. In this work, a novel acceleration test setup will be presented to investigate handling-induced damage at wafer and solar cell surfaces under extreme linear acceleration. A transport belt with and without vacuum fixation is applied to induce various adhesion forces. Various acceleration profiles with up to 50 m/s² are monitored by acceleration sensors. The measured actual acceleration profiles differed from the nominal values disclosing adverse strain peaks and belt vibration of the automation solution. As a result, the transport adjustments are optimized in term of actual stresses to mitigate damages due to abrasion due to sample displacement. As a first application, as-cut silicon wafers are tested for trapezoid or sinusoidal shaped velocity profiles with and without vacuum condition. The displacement was measured as a function of acceleration. The displacement for the high nominal acceleration of 40 m/s² could be reduced to less than 150 µm.