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Failures

Failures

Two thirds of module manufacturers eligible for the 2024 Scorecard experienced at least one test failure. This is the highest percentage reported within the past four Scorecards. The BOM-level failure rate also increased, from 32% of BOMs experiencing one or more failures reported in the 2023 Scorecard, which was up from 26% in 2022 and 2021, to 41% of BOMs for the 2024 Scorecard dataset. These failures included previously reported junction box related issues and power loss, but also an increasing number of delamination issues.

Failure Types

Close up of a junction box gland failure

Safety Failure

Modules with safety failures may be hazardous to operate in the field. Throughout PQP testing, safe operation is determined via wet leakage testing using the IEC 61215 standard, which evaluates the electrical insulation of the PV module. BOMs not meeting the IEC 61215 minimum requirements for insulation resistance are included in the Scorecard's failure statistics.

This module failed wet leakage testing following LETID testing. Kiwa PVEL's investigation revealed that the cable's conductors had become exposed at the junction box gland. This was a failure mode detected on at least five different BOMs from at least three manufacturers within the past year.

Visual inspection showing delamination with measurement tools

Visual Inspection

Visual inspections identify issues that cause premature field failure. Modules are examined for delamination, corrosion, broken or cracked surfaces and other 'major' defects using the IEC 61215 criteria. BOMs exhibiting 'major' visual inspection findings are included in the Scorecard's failure statistics.

This module experienced delamination along the module perimeter following PID testing. This results in electrical creepage distance below the IEC 61730 required minimum and is therefore considered a 'major defect'. Kiwa PVEL has observed a significant increase in this failure mode within the past year, with ten manufacturers submitting modules that exhibited this form of delamination.

Power degradation failure

Power Degradation

Modules with power degradation failures may underperform in the field. Although the PQP does not assign specific pass/fail thresholds for degradation, manufacturers may initiate a retest if power loss exceeds their or their customers’ expectations. Retests are clearly noted in PQP reports. BOMs that undergo a retest due to power loss are included in the Scorecard’s failure statistics..

This module degraded over 15% following PID testing. While likely due to polarization, which may be reversible, this was a particularly egregious case. Nine manufacturers experienced significantly high rates of PID polarization in the past year.

Visual inspection showing delamination with measurement tools

Diode

Kiwa PVEL evaluates the functionality of the module’s bypass diodes after TC and MSS testing. A failed bypass diode can no longer protect the module from hot spots, which could lead to fire risk. BOMs with non-functioning diodes in reverse and/or forward bias are included in the Scorecard’s failure statistics.

A junction box experienced a rapid unscheduled disassembly during TC testing, resulting in rear glass breakage. This was likely caused by an electrical arc within the bypass diode or a JB soldering issue. Four manufacturers had failing bypass diodes in the past year of PQP testing.

Key
Takeaways

Visual inspection was once again the leading failure category.

58% of all failures were detected during visual inspection, with 50% of manufacturers having at least one visual inspection failure. The two largest subcategories of these were delamination detected during pre-stress, TC, DH and MSS, and junction box covers falling off at pre-stress, or during DH or hail testing.

PQP Failure Statistics

This graph shows the percentage of BOMs experiencing a failure in each test sequence of the PQP by failure type.

The most common type of failure is visual inspection major defect, causing more than half of the recorded failures. This is followed by power degradation failures. Initial failures are those that were detected during characterizations prior to stress-testing.

UVID failures are not shown. Visit the UVID page to learn more.

PQP Failure Statistics Graph

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