Crack initiation and growth in PV module interconnection

Abstract

As the cost of PV (photovoltaic) solar panels drops, it is widely expected that solar energy will become the cheapest source of electricity in many parts of the world over the next two decades. To ensure that PV solar modules have a long service life and can meet the PV manufacturer’s warranty, the PV modules need to have high reliability. Solar PV module manufacturers typically provide two warranties: a performance warranty which guarantees 90% of original power output after 10 years and 80% of original output of at 25 years; and an equipment warranty which guarantees their PV module will have a minimum of 10–12 years operation before failure. A critical part of the solar PV module assembly is the ribbon interconnection between the solar cells (i.e. the solder joint interconnections), and failure of the ribbon interconnection can adversely affect the performance and reliability of whole PV module. Ribbon interconnection failures have been linked to the thermal cracks which are initiated in the solder joint material during the high temperature ribbon interconnection manufacturing process; and then the crack propagation and growth associated with the thermal cycling of the ribbon interconnections under higher than ambient temperature PV module operating conditions. This paper reports on the study of high temperature crack initiation and propagation in different PV Module interconnection configurations by using XFEM in ABAQUS software. It concerns a necessary, urgent and fundamental revision of the manufacturing process that lies at the heart of PV module ribbon interconnection manufacture.