Due to a customer demand for a solution for insulation testing for unframed modules, MBJ has developed a new mechanics for contacting frameless modules. The previous solution for contacting with slotted spring plates may no longer be offered due to a German patent.
The new solution is based on a suggestion from VDE regulation PM 434 of July 12, 2006, where it is suggested: "If the modules do not have a metal frame, insulation testing should be carried out with a conductive substitute frame or similar that rests against all edges of the module."
Following this, the contact strips for contacting the side edges of frameless modules were each in the form of a continuous and rigid metal strip, as we believe this design is no longer covered by the patent in suit.
Sufficiently good contacting of the glass edge is also achieved by the spring-loaded mounting of the rigid strips. However, it should be noted that protruding residues of the encapsulation material could negatively influence the result. It would be obvious to solve this problem by using contact springs (see also https://hollandshielding.com/Door-fingerstrips-spring-contacts) or by applying an elastic conductive material (see also https://hollandshielding.com/Electrically-conductive-foam).
However, such solutions are protected by the patent within Germany. In the current version of the patent, the following description and explanation of the design can be found in paragraph [0023] of the patent:
[...] By using such materials, it is ensured that the contact element is elastic enough to prevent mechanical damage to the photovoltaic module when the photovoltaic module is contacted mechanically by pressing on the contact frame or the contact plunger, but at the same time sufficient electrical contact is ensured. Instead of these materials, conventional metal contact sheets or contact foils can also be used, in which case they are advantageously spring-mounted or resiliently supported in a suitable manner so as not to damage the comparatively sensitive module during the contacting process.
Since the patent is a German patent, it would theoretically have been possible to retrofit our systems with contact springs outside Germany, but this is not possible in any case within Germany.
We therefore decided to offer a process-safe solution by means of a camera system. Our inspection system inspects the module in transmitted light during loading into the MBJ Backend Solution (combination of electroluminescence, insulation test and solar simulator).
With this additional camera system, cell spacing can be measured, foreign objects can be detected and broken cells can be identified. In addition, the glass edges can be checked for breakouts and for any protruding residues from the lamination process. Thus, we can offer a process-safe insulation inspection which, in our opinion, does not interfere with the scope of protection of the existing German patent.
Further information about our inspection systems for the PV industry can be found on the web at our product overview.