Abstract

Extending the operational life of photovoltaic (PV) modules is essential for sustainable energy transitions and waste reduction and repairing them is one option to achieve this aim. This study focuses on crystalline silicon (c-Si) modules affected by failures inside the junction box (jbox), where overheated solder joints often interrupt current flow. We explored spot-welding with nickel plates as an alternative to traditional soldering. Three welding strategies are considered through digital simulations to evaluate ease of application and reliability, and the most promising is applied experimentally: horizontal placement with a double-folded plate. The PV modules are assessed before and after repair using current–voltage curves, series resistance measurement, and thermal imaging under direct current injection. The intervention of the jbox successfully restored conductivity and power output, with no evidence of hot-spot formation. Post-repair performance is within ±5% of reference modules in terms of power output, without a significant change in the series resistance of the modules under test, supporting second-life use. The findings confirm spot-welding as a robust and lead-free repair method that contributes to circular economy practices in the PV sector.