Key takeaways:
Quality inspections show recurring defects in soldering, string alignment, and handling across production stages
Packaging-related issues account for a significant share of findings, with damaged packaging contributing to nearly half of CLM observations
Reliability testing highlights ongoing challenges such as UVID in TOPCon and the importance of proper PID pre-conditioning
Manufacturing and product quality in the PV industry have improved significantly over the past few years, driven by continuous testing, findings, and updated standards. Currently, most reliability issues with PV modules and process anomalies are well known. However, real-time testing and inspection data are not widely available to the public.
Intertek CEA, a QA and technical advisory company in the PV industry, has recently released the Quality Report 2026 on Global PV Manufacturing, which includes key risks, defect trends, and supplier performance insights over the last 3 years.
The data comes from inspections of processes and products manufactured in factories in China, Cambodia, India, Indonesia, Malaysia, Thailand, Turkey, the USA, and Vietnam. The inspections are classified based on several parameters, ranging from factory production qualification to the monitoring of processes and final product quality at various stages. These are Factory Audit (FA), Inline Production Monitoring (IPM), Pre-Shipment Inspection (PSI), Container Loading Monitoring (CLM), and Batch Testing.
The report categorizes the findings from these inspections into minor, major, and critical defects, and rates the factories on their performance from A+ to D, with D indicating risk or failure.
Between 2024 and 2025, 50% of factories in China and Indonesia received a D grade in pre-production FAs conducted by Intertek CEA compared with 40% in India. None of the factories during this period earned an A+. Upon comparing yield rates across factories in China, India, and the USA, it was found that factories in the USA have lower yield rates, mainly due to the ramp-up stage of newly built capacities.
On the process side, where inspections typically cover materials, preparation, and all steps before and after lamination, most findings point to the tabbing & stringing, lay-up, and rework stations. Of these findings, the combined share of major and critical issues is about 25%, with critical defects accounting for less than 2.5%. It was found that soldering-related defects are increasing, attributed to the increasing number of busbars and ribbons. Most of these defects are only visible during the final EL inspection after lamination, which is unfortunate, as the module cannot be reworked.
The defects identified during PSI are mostly due to misalignment of strings with busbars. Other common defects identified during visual and EL inspections are cell cracks, microcracks, and scratches, which are attributed to pre- and post-lamination handling of the strings and modules.
The CLM inspection identifies packaging damages, checks the container’s condition and seals, and evaluates stacking and loading methods in accordance with standard operating procedures (SOPs). Damaged packaging is the most common finding, contributing to 47% of total findings in 2025.
Batch testing is a process of sampling final modules at the end of production to test reliability using SOPs for module power degradation. These include potential-induced degradation (PID), light-induced degradation (LID), light- and elevated-temperature-induced degradation (LeTID), and UV-induced degradation (UVID).
Modules made with n-type wafers exhibit a lower LID than those made with p-type wafers. The report presents this comparison; although some outliers still exist for TOPCon modules, the root cause of which is currently unknown. UVID is a key issue for TOPCon modules, and the dataset shows that the average power degradation of TOPCon modules occurs after performing the UVID test at 120 kWh/m².
At the TaiyangNews Reliable PV Module Design Conference 2025, Ingrid Haedrich from Fraunhofer ISE said, “Right now, there is a lot of focus on updating the UVID IEC standard, and the whole industry, including us and major test labs, are involved to make sure it works, not just for TOPCon but also for heterojunction and other technologies.”
At the same conference, Xinrui An from JTPV agreed that the standards usually lag technology, but “it becomes a loop where improving the technology creates new reliability problems, and then you need to study those mechanisms further.” Read through the complete panel discussion of this conference here.
For PID tests, UV stabilization or preconditioning is crucial, as results show significant degradation without UV preconditioning. However, current industrial practice is to perform preconditioning only after PID test results show power degradation of 5% or more. The overall industrial average of PID tests was around 1% in 2025.
There are challenges even after shipping of a high-quality module: poor installation practices, improper handling, and unsafe maintenance, which can lead to microcracks, damage, and early module degradation, as pointed out by Vijay Menon, COO of Navitas Solar, at the recent TaiyangNews Solar Technology Conference, India (STC.I 2026).
Download the complete report, titled Global PV Manufacturing Quality Report 2026, here.