What does a solar panel quality control inspection cover?

Solar Panel Quality Control Inspections

The solar power industry has been experiencing a huge boom in the wake of the Covid-19 pandemic, leading to a growing demand for solar panels, or photovoltaic panels – and as a result of this, there has also been an increase in the need for solar panel quality control inspection.

With so many people staying and working from home during the core lockdown periods of the pandemic, many began to look for alternatives to save on the higher energy costs they were experiencing. With the exponential improvement in solar panel technology over the past 10 years, costs have also fallen, making solar power more accessible and affordable for the average home-owning customer, not just for large businesses.

In several countries, increased government subsidies coupled with growing environmental awareness and the desire to find alternative means of power have also been a major factor in the demand for solar panels.

All of this has led to an uptick in demand for solar panel inspections, as manufacturers work to keep up with the demand.

What is a solar panel and where are they made?
A solar panel, also known as a photovoltaic module, is a highly engineered piece of equipment assembled in a mounted framework, which is installed either on rooftops (common in North America) or on raised structures (common in India). These panels harness energy from the sun to generate electricity directly into the building or structure it is connected to.

Although Asia dominates the list of exporter countries for solar panels, they aren’t the only region to manufacture and export the product. The top 10 list of solar panel exporters are:

    • China – 43.1% of solar panel exports come from here
    • Malaysia – 9.8%
    • Japan – 7.4%
    • South Korea – 6.5%
    • Vietnam – 5.8%
    • Germany – 4.6%
    • Taiwan – 4.4%
    • USA – 3.4%
    • Thailand – 2.6%
    • Singapore – 2.1%

With so many different countries manufacturing solar panels to individualized brand specifications, manufacturers must ensure each complete part of the solar panel they have been designated to make, is uniform. This achieves both safety as well as effective functionality of the final product. Everything from cells, controllers, converters, inverters, batteries, photovoltaic panels, junction boxes, connectors, cables, back sheets to electric boards and glass, must conform with one another, as this is crucial to the performance of the fully manufactured solar panel.

What are the main quality issues for solar panels?
One of the main challenges within the solar panel manufacturing industry is quality defects. With solar panels, what may appear to be the tiniest imperfection can actually have a major impact on the working life of the final product. Needless to say, it is imperative that solar panels are not only manufactured using high-quality components but that they also undergo stringent quality control inspections – whether through an in-house QC inspection or a third-party inspection – before shipment.

The most common defects that quality control inspectors look for on the manufactured photovoltaic cells include, but is not limited to: water ingress, wrong cell color, marks on the panel, bubbles on the panel, foreign materials within the cell, traces of glue on the junction box, micro-fractures on the solar cell, broken or chipped solar cells, scratches on the glass, solar cell string alignment, incorrect dimensions, incorrect cable length, insulation resistance, and battery performance.

What are the control factors for a solar panel quality inspection?
As noted earlier, several photovoltaic cells together make up a solar panel of differing dimensions (based on the number of cells required for the panel to convert sunlight into electrical energy). This need for precise power conversion means that it is extremely important to maintain control both before and during production.

Pre-Production
Before the actual production process begins, it is important to pre-select the cells that will be integrated into the final solar panel, verify the glass control process for mechanical resistance and transparency control, check the lamination time, and confirm the different stages of control planned through the production process.

Post-Production
After the solar panel has been fully assembled, ProQC recommends manufacturers perform Pre-Shipment Inspections (PSI), to ensure the final product quality and conformity with customer specifications.

Several elements of the complete solar panel are inspected during the final QC inspection process. The end-to-end verification process follows this guideline checklist:

1.Visual Inspection:

  • Physical condition – appearance and cleanliness of the product
  • Verification of the overall aesthetic view of the solar panels, batteries, inverters, solar charge, cables, and accessories. Each of these must be free from any damage, deformation, scratches, dents, or dirt
  • Checking that the sealant on the solar panels is tight and properly affixed around the edges
  • Ensuring there is nothing broken, no cracks on the solar panel laminate, no damage on the frame, all the fixing/installation/drain/grounding holes, junction box, and anything else required in the product specifications, must be present
  • Making sure the correct branding and origin of the various components are present for the: glass, tedlar, aluminum frame, cells, junction box, cables, MC4 connector, inverters, solar chargers, and batteries

2.Dimension Inspection:

  • Length
  • Width
  • Thickness
  • Diagonal difference
  • Labels

3. Function & Special Tests:
The product must comply with all the information provided, so the solar panel quality inspection must include the operation of each function intended for use.

  • Power/voltage/current test charging/discharging test
  • Hi-Pot test
  • Temperature check
  • Polarity check
  • Assemble a sample of solar panels with complete connections of the inverter, solar charger, and batteries, to ensure it works as it should

4. Logo, labeling, markings check:

  • Barcodes: all need to be clean and positioned as per specifications
  • Logo: quality, colors, dimension, positioning, and alignment
  • Label & marking: correct content within the label and marked appropriately
  • Verification and check of the rating label of each product to be as per specs

5. Packaging inspection:

  • Correct contents and quantity of items/accessories within the package
  • Contents of box are well protected to avoid any damage during transit
  • Shipping marks and labels are positioned correctly
  • Retail package artworks are correct
  • Presence of correct printed literature within the package

Performing quality control for the solar panel manufacturing industry requires a critical eye, and third-party inspectors can bring valuable insight to the process.

Pro QC is a global trusted third-party inspection company offering quality control services to the solar panel industry in China, Vietnam, South Korea, Thailand, Taiwan, Malaysia, the USA, and 88 more countries. Visit www.proqc.com to learn more about our quality solutions.