EU PVSEC Programme Online
EU PVSEC 2021, 6 - 10 September 2021
Presentation: 4BO.5.1 Enabling Climate Specific Modelling of Thermomechanical Fatigue in PV Module Interconnects by Help of Machine Learning Techniques
Type: Oral
Date: Tuesday, 7th September 2021
17:00 - 18:30
Author(s): G. Otnes, D. Lindholm, H. Fjær, L. Kvalbein, P. Seljom, S.E. Foss
Presenter / Speaker: G. Otnes, Institute for Energy Technology, Kjeller, Norway
Event: Conference Conference
Session: 4BO.5 Interconnects and Soldering
Topic: 4. 1 PV Module Design, Manufacture, Performance and Reliability
Summary / Abstract: Degradation of cell interconnects is typically found among the main degradation modes in photovoltaic (PV) modules [1], potentially leading to significant power losses, hence revenue loss and/or safety concerns [2]. Such degradation can be caused by corrosion, as well as circuitry breakage due to mechanical and/or thermomechanical fatigue. Several studies based on finite element (FE) modelling have investigated thermomechanical fatigue in interconnects, and its dependence on e.g. module bill-of-material [3-4] and module and cell size [5]. Typically, temperature profiles from thermal cycling experiments is used in the modelling, but attempts have also been made to model the effect of actual outdoor temperature profiles. To keep computational demands on a reasonable level, studies have until now either used simpler 2D-models to look at longer time-periods [6], or looked at a couple of days representing certain conditions in a given location [3],[7]. In this contribution, we use unsupervised machine learning techniques to select a small number of days (5- 10) from a long timeseries (3-10 years) of module temperature data, for locations in different climate zones. The temperature profiles of these few days are selected such that they give a good statistical representation of the overall variety of temperature profiles experienced in the given location. In this way, modelling of thermomechanical fatigue of interconnects for specific climates or locations is possible within reasonable computational times also with a 3D FE-model. Such a model is capable of capturing stresses in both the interconnect ribbon and in the solder layer [4].