Hotspots are localized overheating events in individual solar cells caused by cell defects, partial shading, cell fractures, or faulty solder joints. Affected cells change from being generators to consumers and can heat up to over 150°C.
Untreated hotspots can lead to destruction of the encapsulant film (browning), delamination, glass breakage, and in extreme cases fire. Particularly with modern high-performance modules (>400 Wp), the thermal stresses are higher than with older module types.
The standard method is infrared thermography per IEC 62446-3. PV-BESS-Assessor performs drone-based thermography inspections for large PV systems, complemented by electroluminescence for root cause diagnosis at the cell level.
Temperature differences of >20 K compared to adjacent cells are considered critical. Above >40 K difference, there is an acute fire risk. IEC 62446-3 defines three categories: <20 K (non-critical), 20–40 K (monitoring required), >40 K (immediate action required).
Hotspot Analysis: 87 Modules with 14% Yield Loss
Real anonymized investigation case with measurement data, timeline, and economic evaluation.