DELAMINATION AND FATIGUE ANALYSIS OF SILICON SOLAR CELLS USING FINITE ELEMENT METHOD
Fracture of silicon solar cells in photovoltaic (PV) modules are widely reported and a wellknown issue in the PV industry, since it is exposed to adverse climatic conditions and varying temperature loads. A commercial silicon solar cell is mainly composed of four different layers. This thesis investigates delamination failure and thermal fatigue failure due to alternating temperature loads using finite element method (FEM) simulation.
The delamination of the encapsulant (EVA) layer and the cell interface was simulated using
finite element (FE) simulations in the COMSOL Multiphysics software. The adhesion between the
layers were modeled using the cohesive zone model (CZM). The CZM parameters such as normal
strength and penalty stiffness were used for the bilinear traction-separation law for the cohesive
model in a 90-degree configuration. The critical energy release rate (πΊπΊππ) was experimentally calculated as one of the CZM parameters. A uniaxial tensile test of the upper layer of the cell was conducted to determine the material properties of the solar cell layers, and that information was
later used for FE simulations. To validate the simulation, we compared the peeling force graph
from the experiment and FE simulation, and it was found both graphs showed a maximum peeling
force of 120 N.
Finite element simulations were also conducted to predict the stress variations in the silicon
solar cell layer due to alternating temperatures. An alternating temperature function was developed
using triangular waveform equations in the COMSOL Multiphysics software. For this simulation,
a 3D model of the cell with a 90-degree peel arm was used, like in the peeling simulation. A
maximum stress of 7.31 x 10β3 π/ππ2 was observed on the encapsulant (EVA)/cell layer, but no
delamination was observed for the given temperature range. In future work, we plan to explore the
calculation of fatigue life using thermal simulation to predict the reliability of a solar cell.
History
Degree Type
- Master of Science
Department
- Mechanical Engineering
Campus location
- Hammond