Study of manufacturing and hotspot formation in cut cell and full cell PV modules

Abstract

The photovoltaic cell pattern and geometry affect the origination, level and distribution of stresses in the modules. The cut cell patterns can be potential alternative of conventional full cell patterns in terms of enhanced stability, reduced hotspot effects, etc. Here, we study the thermo-mechanical behavior of cut cell (half cut and one by three cut cell) and full cell modules during manufacturing and hotspot formation. The 3D geometrical models of modules with maximum details are simulated for these processes. Modules with cut cells are found more resistant to thermo-mechanical loads. The transitory and permanent hotspot cycles with different temperature ends are applied; and it is found that the stress level increases with the increase in temperature and dwell time of hotspots. Due to permanent hotspots with upper extreme end of 110 °C, the busbars experience compressive stresses of −137 MPa, −122 MPa, and −106 MPa in full, half cut, and one by three cut cell modules respectively; and cells experience compressive stresses of −76 MPa, −80 MPa, −72 MPa in full, half cut, and one by three cut cell modules respectively. With the use of cut cells, interconnectors thickness can be reduced and parametric analysis shows that the thinner interconnectors lead to lower stresses in cells. During thermal loading, strain energy is stored in the interconnectors due to deformation and it increases with the increase in thermal loading i.e. for each degree rise in temperature, strain energy increases. In addition, solutions to avoid or reduce hotspot formation are also outlined.