Failures in Testing

“Enerparc takes quality seriously; we leverage PVEL’s detailed test reports to make procurement decisions. While we believe that Top Performer recognition is an encouraging indictor of product reliability, we review the detailed test reports and will not source modules that exhibit any type of failure in PVEL’s Product Qualification Program for our projects.”

Erik Lohse, Team Leader Quality Management, Enerparc

Key Takeaways

Click through the key takeaways below.

Some manufacturers experienced no failures and others had multiple

Although a similar share of bills of materials (BOMs) experienced at least one failure in 2022 and 2021, just one manufacturer accounted for 40% of all failures in the 2022 Scorecard.

Damp heat failures increased, but not for most manufacturers

More BOMs experienced failure in damp heat testing than in any other test, but less than 15% of manufacturers experienced a DH-related failure.

Junction box issues are a primary driver of failure

In the last four successive Scorecards, we have observed persistent safety concerns with junction boxes. They remain a common source of failure, with 30% of participating manufacturers having one or more junction box related failures.

PQP Failure Statistics

PV Module Reliability Test Result Chart: failures across test sequences

This graph shows failures observed in each test sequence of the PQP by type of failure.

The most common type of failure is safety, followed closely by power degradation and visual inspection defects.

Initial failures are those that were detected during intake characterizations prior to testing.

Failure Types

Safety Failure

Modules with safety failures may be hazardous to operate in the field. Safe operation is determined via wet leakage testing using the IEC 61215 standard, which evaluates the electrical insulation of the PV module.

The module cable was damaged, exposing metal, which led to a electrical fault during wet leakage testing.

Visual Inspection

Visual inspections identify issues that cause premature field failure. Modules are examined for delamination, corrosion, broken or cracked surfaces and other defects using the IEC 61215 criteria.

Poor frame sealant allowed the laminate to separate from the frame during static mechanical load testing.

Power Degradation

Modules with power degradation failures may underperform in the field and ultimately result in financial losses for the asset owner. Although the PQP does not assign specific pass/fail thresholds for degradation, manufacturers may remove products from testing if rates are above expectations. They typically change BOMs or production processes, then submit new samples for retesting. Retests are clearly noted in PQP reports.

This module set the record for the highest amount of power loss following DH testing in PVEL’s history.

Electroluminescence

Modules undergo EL imaging throughout the PQP test sequences. No pass/fail thresholds are applied to EL images, but manufacturers may discontinue testing if the level of cell damage observed is higher than anticipated. In these cases, PVEL records an EL failure and a new sample may be submitted for retesting.

This module arrived at PVEL with a shattered cell. The manufacturer decided to remove it from testing.

Diode

PVEL evaluates the functionality of the module’s bypass diodes after stress testing. A failed bypass diode can no longer protect the module from hot spots, which could lead to fire risk.

A diode in this module failed in short circuit following 400 thermal cycles. 1/3 of the EL image is completely dark, which indicates ~33% power loss.

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