Frame detachment simulation of PV modules under mechanical load

Abstract

Photovoltaic (PV) laminates are attached to aluminium frames using adhesives, which provide structural stability. In most Finite Element Method (FEM) simulations of PV modules, the importance of frame attachments and adhesion between the frame and PV laminate is ignored by using a simplified model in terms of geometry and material model, though they have a definite impact on the behaviour of the module [1]. This can be due to the increase in the computational cost and the complexity of identifying the appropriate material model for the adhesives. However, the adhesive has a strong influence on the behaviour of the PV module exposed to mechanical load. High loads might lead to the detachment of the adhesive and, consequently, the failure of the PV module. Studying the influence of the adhesive, its response under load, and understanding the strength of the adhesive are essential for a correct modelling of the PV module and hence preventing damage to PV modules. Therefore, within this work, two materials, a one-component silicone (1C silicone) and a two-component silicone (2C silicone), are analysed and modelled using a 2-parameter Mooney-Rivlin incompressible hyperelastic material model. The material model is validated using a single lap shear test. A suitable failure criterion is identified at ambient temperature for one-component silicone through an experimental investigation focusing on the tensile and shear stress states of the adhesive. A FEM simulation is performed to determine the stresses in the 1C silicone in a PV module under mechanical load. The comparison to the failure stresses shows, that the stress values within the adhesive are far below the failure stress and hence no frame detachment is expected.