Thermo-Mechanical Simulations

Using the Finite Element Method (FEM), we couple structural mechanics with other physical fields, such as heat transfer for thermomechanical simulations. We are capable of solving very complex and thus computationally intensive problems through the interfacing with a CAD program and the use of a High Performance Computing Cluster (HPC cluster).

R&D Services for Thermo-Mechanical Simulations

In the Reserach Topic Module Technology we offer the following services in the field of thermo-mechanical FEM simulation:

• FEM modelling of any component and calculation on a High Performance Computing Cluster (HPC cluster)
• Virtual product development and material qualification
• Virtual product optimization
• Material characterization to determine the material properties, e.g. as input for FEM simulations
• Experimental validation in the test laboratories of Fraunhofer ISE 

Thermomechanical Optimization of PV Modules

In a PV module, stresses occur during production and operation due to temperature changes and mechanical loads. These stresses can lead to cracks in the solar cells, joints or fatigue of the cell interconnectors. Simulations help us to understand these stresses and develop strategies for stress reduction. In the manufacturing process, thermomechanical stresses occur mainly during the interconnection of the solar cells and module lamination. If the modules are installed in a PV power plant, mechanical and thermal loads act on the modules due to weather conditions.

In simulations, we reproduce the manufacturing processes and the load scenarios. For example, we simulate the mechanical load test and the thermal cycling test according to the requirements of the IEC 61215 test standard or use measured climate data to determine the thermal stresses that occur in real operation. From the FEM simulations we can derive how damage to the module can be avoided.

ECA Joining of Shingle Modules

In the shingle interconnection, solar cell strips are connected in a way comparable to roof shingles. The absence of cell interconnectors results in a particularly aesthetic and homogeneous appearance of PV modules. They are also more resistant to shading. Due to their mechanical properties, electrically conductive adhesives (ECA) are particularly well suited for shingle connections. 

In the Reserach Topic Module Technology, we use thermomechanical FEM simulations to investigate the mechanical behavior of such an ECA shingle joint. Special attention is paid to the viscoelastic material behavior of the ECAs.

Optimization of the Thermal Resistance of a Junction Box

Bypass diodes are located in the junction box of a PV module. If a bypass condition occurs, the high currents can cause the bypass diodes to generate a lot of heat. If the heat is not dissipated well, this leads to overheating of the junction boxes and thus to module failure.

Simulation of PV noise barriers

In the ongoing project PVwins, noise barriers with integrated PV modules are being developed for use on motorways and railroad tracks. With FEM we simulate the acousto-mechanical behaviour of a noise protection element.