Although designed to protect a module from the effects of reverse bias, the quality of the junction box which houses the protective diodes has started to come into question. The thermal design and general durability of the junction box is vital to ensure long-term reliability of the module.
Over the past 2 years we have identified 6451 modules across 1.25GW and 25 module manufacturers with activated or faulty diodes. This causes a module power loss of one third as well as losses across the connected module string.
We have also recorded 1372 modules with abnormally hot junction boxes. Evidence has suggested that an elevated temperature in a junction box is a likely precursor to a diode failure and we have been able to make this correlation with repeat thermographic inspections.
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