Electrical Insulation Tester for Solar Modules after Scribing

This measurement solution performs an electrical insulation test between the solar cells after scribing. The system detects shorts and minimum resistance between neighboring cells which can lead to a loss of cell effectiveness and an overall reduction of the performance of the solar module


The Insulation tester's main component is a measurement interface. A row of metal contact probes is installed along a contact bar. This board-like interface is easily installed on a frame and is placed horizontal above the solar modules flowing through the production line after scribing. The amount and distance of the lined up contact probes depends on the size of the panel and, more importantly, on the number of cells - one probe for each cell. The modular design of the bar interface enables customers to easily exchange the contact bar for applications with different panel sizes.

The measurement interface is connected with a controller box including a single board computer as well as an pneumatic system that lifts and lowers the contact bar for measurement.

Dr. Schenk can deliver every type of inspection system that requires handling: We design and build standalone solutions where inspection and handling form a contained and independent system, like particle counters, edge inspection systems and the LabInspect offline testing stations.

Insulation test probes

How does the system detect shorts?

As soon as a panel arrives at the measuring point, the line control unit communicates with the Electrical Insulation Tester and the panel stops for the measurement cycle (max 3 seconds). Within this period, the contact bar is lowered onto the panel. The spring mounting of the probes guarantees an optimal height compensation, so that they have a clear contact with the cells and at the same time keep the pressure at a minimum in order to prevent damage to the panel.

With a low voltage on the contact probes the electrical resistance between neighboring cells is measured. By this analysis the systems can detect, if cells are properly insulated or if an interruption of scribes will cause a short circuit. Cells that do not show an infinite resistance are damaged and depending on the parameters set by the line operator for this production these panels can later be either rejected from further production. After the measurement cycle is finished, the contact bar will lift to its original position.

For fully automated production lines this SolarMeasure system does not even require a visualization software as it communicates directly with the line control unit and can send signals to restart the line flow.