PVEL’s 2021 PV Module Reliability Scorecard Out

• PVEL's 7^th edition of PV Module Reliability Scorecard says BOMs need to be stressed upon since unproven ones can cost financially and from safety point of view
• 26% of the BOMs eligible for this year's scorecard had at least 1 failure as compared to 20% in 2020
• Junction box defects continue to hound solar modules as 1 in 3 manufacturers tested for the report, experienced safety failures due to these

Downstream solar test lab PV Evolution Labs (PVEL) argues that to ensure solar modules are reliable, buyers must specify their desired bills of material (BOM) in supply contracts since the quality of a PV module depends in part on the materials it contains. Still, as PVEL's Chief Commercial Officer (CCO) Tara Doyle points out, many buyers never request BOM details from suppliers.

In its 2021 PV Module Reliability Scorecard, the 7^th annual edition of this research report, PVEL counts 26% of the BOMs eligible for this year's scorecard had at least 1 failure as compared to 20% in 2020 (see PVEL Releases 2020 Module Reliability Report). The greatest number of failures occurred during the mechanical stress sequence to check how the module would fare under extreme weather. PVEL said it included this test recently to its Product Qualification Program (PQP) to address durability concerns.

Deploying 'unproven' BOMs in the field can have profound financial implications and safety consequences, fears PVEL while pointing out the race to bring out 500W commercial modules in brand-new factories.

At least 1 in 3 manufacturers tested for the report, experienced safety failures due to junction box defects versus 1 in 5 in 2020, and what's more, the majority of these tests were observed before these could be tested.

According to the authors of the report, 100 million solar cells are soldered every day to meet PV module demand, and to address climate change, the world would need to reach at least 1 billion cells soldered per day. While technical advancements in PV technology are welcome especially when these promise to enhance power output and bring down cost of solar power, they stress that quality cannot be sacrificed for scale.

"An unprecedented expansion of PV module manufacturing capacity is underway. New factories and production lines are vital as demand for solar power soars, but buyers must be vigilant to avoid the risks inherent to rapid growth," explained PVEL CEO Jenya Meydbray. "The preventable safety failures observed in this year's Scorecard underscore the complex challenges that manufacturers face as they race to meet demand in a highly dynamic global market."

Some of the other key takeaways from the report include the following:

• Compared to PVEL's historic PQP results, monocrystalline wafers and Passivated Emitter and Rear Contact (PERC) cells exhibit stronger thermal cycling (TC) performance than multicrystalline wafers and Aluminum Back Surface Field (Al-BSF) cells.
• Bifacial TC results showed both glass/glass and glass/backsheet bifacial modules achieving Top Performer status, with the amounts of front-side and rear-side power degradation aligned.
• 30% of the Top Performers achieved less than 2% degradation before the 48-hour high-heat, high-current BO stabilization treatment after DH2000. The remaining Top Performers achieved less than 2% degradation after power loss recovery from BO stabilization.
• Many module datasheets continue to advertise products as "PID resistant", yet both the median and average degradation from PID was higher in the 2021 Scorecard dataset than in the 2020 Scorecard dataset — the highest in PVEL's history.
• Test results for both boron- and gallium-doped PERC modules show that LID and LETID can be solved, but it is possible that new degradation modes will emerge in the field over time
• All 2021 PAN Top Performers are bifacial modules because of the energy yield boost from their rear-sides.

PVEL has named 117 models of PV modules from 26 manufacturers as Top Performers in the report that's available for free download on its website.

Speaking during TaiyangNews' 1^st Reliable PV Module Design Conference on October 9, 2020, Meydbray said that performance test certifications are helpful to keep really faulty products out of the market, but they do not always end up keeping all the faults out of the product that may start appearing after a few years on the field. He stressed on third party testing, beyond the IEC tests, that can test module quality thoroughly (see TaiyangNews Reliable PV Module Design Conference).

On the occasion, we launched our TaiyangNews Backsheet & Module Encapsulation Market Survey 2020, which also provides detailed product specs from leading suppliers' models. It is available for free download.