Suheir Nofal

Suheir Nofal

PGSB Fellow
Palestine Polytechnic University & RWTH Aachen University

Home Palestinian University: Palestine Polytechnic University

Specialization: Electrical Engineering

Accurate Specialization: Photovoltaics

Degree aims: PhD

FZJ Supervisor: Dr. Bart E. Pieters

Center in Juelich: Full Name with abbreviaion: Institute of Energy and Climate Resrearch (IEK-5)

Affiliated University in Germany: RWTH Aachen University

Department: Electrical Engineering

Faculty: Faculty of Photovoltaics.

The mission research period : from 2019 - to 2021

Title of  Research: The Dynamics of Hotspot Formation in Thin-Film Solar Modules

Research Purpose: The performance of thin-film solar technologies tends to degrade when a module is partially shaded. A solar module consists of many series connected cells. Under partial shading conditions one or more of these cells may become reverse biased. As a solar module can produce rather high voltages the reverse biased cells are driven into junction breakdown. Typically, junction breakdown does not occur in the whole area of the reverse biased cells. Instead one or more small areas conduct all the current, and thus the power is dissipated very locally. As the commonly used encapsulation materials are poor conductors for heat, and the solar cell itself is very thin, the generated heat cannot quickly flow away and a so-called a hot-spot is formed. These hot spots can reach very high temperature in a very short time (we measured up to 1740 K) and often permanently damage the solar cell. For some thin-film technologies we know that junction breakdown is very sensitive to the temperature and thus a good understanding of this mechanism needs to consider both electrical and thermal aspects.