Impact of interconnection failure on photovoltaic module performance

Understanding the impact of failures on performance is necessary for any technology's development. There are many interconnection schemes that have emerged as the field solar photovoltaics has matured, but the most commonly used and well‐understood scheme is ribbon tabbing. In the field, the contacts between the ribbons and the cell metallization can fail via corrosion or solder joint failure. Solder joint failures are simulated by systematically cutting the interconnections of four‐busbar, multicrystalline silicon modules. It is shown that not only do the failures themselves contribute to performance loss but the location of the failed interconnection with respect to those near it is also important. Different breakage schemes and their impact on performance are compared. Different methods of calculating series resistance are evaluated. Multi‐irradiance performance is used to show how energy yield models can inaccurately predict module output for modules with high series resistance. Systematic disconnections were induced in the interconnection ribbons of a set of modules to simulate the effects of solder joint failure in the field. Busbar redundancy is shown to be critical in mitigating the impact of this failure mode on module performance. Three different methods of calculating series resistance are investigated and compared, and the influence of multi‐irradiance performance on energy yield predictions in different regions shows deviations from assuming one‐sun performance.