Cell-Level Reliability Testing Procedures for CIGS Photovoltaics

Abstract: The reliability of photovoltaics is commonly studied at the module level. Many reliability problems originate from module attributes, such as metal interconnections to cells, junction boxes. However, significant work in reliability can also be done prior to module design. Testing for reliability earlier in the research cycle increases the probability of avoiding common module reliability problems before cell changes are implemented on a large scale. Cell-level reliability studies can thus lower the rates of module failures in the field and provide confidence to investors that new technologies will perform as advertised. This report summarizes how we investigated three reliability concerns in Cu(In,Ga)Se₂ (CIGS) photovoltaics at the cell level: metastability, shading-induced damage, and potential-induced degradation (PID). Examining these concerns required developing robust measurement protocols including the fabrication of novel testing structures. This information will allow readers to incorporate sound metrics for investigating reliability phenomena and aid their studies of cell and module reliability improvements. Graphic abstract: [Figure not available: see fulltext.]