When evaluating polycrystalline solar panels for potential-induced degradation (PID) susceptibility, manufacturers and third-party testers follow a rigorous protocol rooted in international standards like IEC 62804. The process starts by replicating real-world stress conditions that accelerate PID mechanisms. Panels are exposed to high temperatures (typically 85°C), elevated humidity levels (85% RH), and a sustained negative voltage bias (-1000V relative to ground) for 96 hours in specialized environmental chambers. These parameters simulate years of field exposure in climates prone to PID, such as coastal regions with high humidity or installations with ungrounded mounting systems.
During testing, engineers monitor three critical parameters: leakage current between the panel’s semiconductor layer and frame, insulation resistance degradation, and power output decline. Advanced labs use electroluminescence imaging to detect microscopic shunts in solar cells caused by sodium ion migration – PID’s primary failure mechanism. A polycrystalline solar panel showing more than 5% power loss or insulation resistance drop below 40 MΩ typically fails PID certification.
Post-test analysis involves dissecting module materials. Technicians examine the ethylene-vinyl acetate (EVA) encapsulant for conductivity changes and test the backsheet’s dielectric strength. Newer test protocols now include temperature cycling (-40°C to +85°C) immediately after humidity-freeze cycles to assess how thermal expansion affects PID pathways in polycrystalline cells’ grain boundaries.
Leading manufacturers have developed proprietary PID recovery tests, where panels are subjected to reverse biasing after PID exposure. This determines whether performance losses are reversible – a key differentiator in product warranties. Field correlation studies show lab results must predict less than 2% annual PID-related degradation for 25-year performance guarantees to remain valid.
Cutting-edge facilities employ real-time quantum efficiency measurements during stress tests, tracking how PID affects spectral response across different wavelengths. This reveals whether sodium ion accumulation disproportionately impacts blue or red light conversion in polycrystalline silicon – a critical factor for panels used under varying atmospheric conditions.