Cracking Down on PV Module Design

December 15, 2020

We’ve all seen the damage that a major storm can inflict on solar modules. Broken glass and mangled frames are easy to identify after a force majeure event. While underlying damage is more difficult to detect, it can still be devastating: significant power loss and safety issues may develop over time if the solar cells within PV modules are cracked.

Cell cracks are caused by thermal and mechanical stress. For example, they can result from manufacturing defects, extreme weather events (i.e., wildfires, hailstorms, tornados), mishandling and even improper maintenance. Cracks appear as dark lines or areas in electroluminescence (EL) images.

Cell cracks may not reduce energy yield immediately, but they can expand and become more severe over time. They can even create hotspots that accelerate backsheet delamination and degradation, increasing the likelihood that ground and arc faults will occur. Identifying and documenting cell cracks for insurance claims usually requires field EL imaging.

Several trends in PV module technology and design can actually increase cell crack susceptibility. Kiwa PVEL’s PV Module Product Qualification Program helps PV module buyers evaluate the durability of different products through independent performance and reliability testing. Our rigorous test sequences reveal how specific PV module bills of materials (BOMs) respond to thermal and mechanical stress.

Our white paper explains the challenge of cell cracks and shares new findings from Kiwa PVEL’s mechanical stress testing to help downstream solar PV module buyers, investors and asset owners mitigate technology risk.