Study on Creep of Lightweight Flexible Crystalline Silicon Photovoltaic Module

The long-term creep behavior of lightweight flexible crystalline silicon photovoltaic (PV) modules under combined mechanical and thermal loads remains poorly understood, limiting reliable design for field applications. This study therefore investigates how stress (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4-50 \text{MPa}$</tex>) and temperature (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$25-85{ }^{\circ} \mathrm{C}$</tex>) influence time-dependent deformation and recovery in two module types differing only by back-sheet material (SMS and US). Creep–recovery tests reveal that higher stress and temperatures above 65°C markedly accelerate the three stage creep process, with the US module showing superior resistance at elevated temperatures. Burger viscoelastic model calibrated to experimental data with average errors below 5% captures the stress- and temperature-dependent viscoelastic parameters. These findings fill a critical gap in understanding flexible PV module mechanics and offer quantitative guidance for material selection and durability assessment.