Determination the Reliability of Solar Modules in Analogy to Glass in Buildings

In recent years, photovoltaic (PV) module designs have doubled in size, introducing XXL modules, with approximately 3 m². Meanwhile, the single glass height of glass-glass modules has decreased from 3.2 mm to 2 mm or less. This reduction, coupled with decreased frame stiffness, raises concerns about load-bearing capacity and modules increasingly show damage like glass and frame breakage in the field. PV module load bearing capacity is determined via MQT 16, a static mechanical load test in accordance with IEC 61215. This test inadequately represents real damage scenarios as it does not consider material strength variability and time-temperature behavior of the interlayer. Instead, the design method from the construction industry can be used to determine the static reliability of solar modules. Regardless of the material, the partial safety concept is used, which considers variations in loading and material. Components or structures can then be dimensioned using a suitable mechanical model. For many years, glass has been used in façades and roof structures without frequent breakage due to static overloading. This paper describes the current problems related to unexpected solar module damage, illustrates load-bearing behavior of glass-glass modules considering material, mounting, and mechanics, and presents the construction industry design method.