The reliability investigation of PV junction box based on 1GW worldwide field database

The reliability of junction box plays the critical characteristic in PV development. We perform the statistic analysis from 3.8 million modules over 1GW capacity during the first five year system operation. There are total 73 faulty junction boxes spreading out in 26 of over 1,250 project sites globally with 19.2ppm failure rate. Around 85% of failure is contributed by system install sector within first three months after on-grid. Main failure modes include burnt bypass diode, burnt junction box and low power, while 72.6% portion of the root cause results from energy over stress from system,. Other root causes are also inspected in detail, and the result corresponds quite well with statistic failure mode analysis. In addition, suggestion for preventing reliability risk is also proposed for each sector respectively through whole PV value chain.