Numerical simulation of the delamination behavior of photovoltaic modules

Abstract

In this work, the delamination behavior of photovoltaic (PV) modules is investigated by numerical simulation. This work is the first to propose a numerical model representing a full-size PV module using cohesive zone elements to simulate the delamination process. The thermal expansion mismatch of the different materials can explain the delamination behavior of PV modules. The model simulates the manufacturing process and five thermal cycles - an accelerated aging test used in the PV industry - to assess how the thermal expansion behavior of materials influences the risk of delamination. Furthermore, the impact of humid aging and UV aging on the delamination tendency are investigated for the first time. The model identifies the preferential delamination sites in a PV module, which align with experimental observations. Additionally, the influence of boundary conditions on the model’s predictions is examined and discussed. The need for better estimation of adhesion energy is highlighted, as is the lack of experimental Mode II adhesion energy data in the literature.

This numerical model displays the stress distribution at the encapsulant/glass interface. The influence of the cell size on the stress level reached at the encapsulant/glass interface is also revealed. The inter-cell region absorbs deformation in the encapsulant, reducing interface stress and mitigating the risk of delamination.

This simulation tool can model any PV module, provided the material properties are known. This work can be used to investigate new PV module dimensions and new materials to reduce the risk of delamination.