Requirements for the reliability of cell connections

New types of photovoltaic modules are becoming increasingly complex in terms of busbars and connection points. Thinner cell connections and the switch from flat to round wires mean that previous two-dimensional simplifications in mechanical simulation are no longer acceptable, as areas of bending that were previously not taken into account are now also affected.

The reduction of heavy metals requires the substitution of lead in solder joints, making alternative lead-free solders and conductive adhesives more important. At the same time, alternative materials for lightweight modules without glass lead to increased stress on cell connections due to large differences in expansion.

Thermal-mechanical loads caused by temperature changes are an essential aspect of PV module development. Knowledge of module temperatures at different locations, depending on environmental parameters and module design, is crucial for the module's “mission profile.”

The advanced processing of weather data plays a crucial role in the creation of load profiles for evaluating the thermomechanical fatigue of photovoltaic modules. More accurate weather data allows the stress on the modules to be predicted more precisely and better understood.

In order to meet the complex requirements, the further development of existing simulation models is being driven forward, in particular to reproduce round wires more realistically. This is necessary because round wires exhibit altered mechanical behavior that is not fully captured in previous models.

In addition, the influence of new materials and material combinations on the reliability of cell connections is being intensively analyzed. These investigations are particularly important because the introduction of new materials can change the mechanical properties of the modules, which has a direct impact on their long-term stability and functionality.