Towards integrated photovoltaic applications: Lightweight silicon heterojunction solar modules with different encapsulation materials and their damp heat stability

Lightweight photovoltaic (PV) modules are able to open up vast new scenarios for PV applications, like building-integrated PV (BIPV) and vehicle-integrated PV (VIPV). Silicon heterojunction (SHJ) solar cells have been recognized as one of the most advanced technologies for improving solar power generation. However, SHJ solar cells are inherently susceptible to damp heat-induced degradation (DHID), which is a critical concern for their application. In this study, lightweight SHJ mini-modules with a low area density (∼ 2 kg/m2) while preserving high power density (∼ 70 W/kg) were fabricated using SHJ solar cells with different encapsulation materials and architectures. A comprehensive analysis of the module degradation was carried out, focusing on the optical and electrical properties of the modules and the chemical properties of the encapsulants after 1000 h of accelerated damp heat (DH) aging test. The efficiency loss in lightweight SHJ solar modules after DH test varied significantly, ranging from 3.22 %rel to 54.06 %rel, depending strongly on the encapsulation materials. The increase in series resistance (Rs) was generally the dominant cause of module efficiency degradation. An optimized damp heat-stable lightweight SHJ module was successfully fabricated, with only 0.47 %rel efficiency degradation after 1000 h of the DH test. Its stability is almost the same as that of the glass/back sheet module. The comparative study and comprehensive investigation provide insights into the DHID behavior of lightweight SHJ solar modules with different encapsulation materials, contributing to the development of lightweight SHJ solar modules with high DH stability for industrialized mass production.