Solar Panels Working but Not Efficient? Check for Delamination

  • Post last modified:March 30, 2026

Solar Panels Working but Not Efficient? Check for Delamination

For many homeowners and industrial facility managers, the installation of a solar photovoltaic (PV) system represents a significant financial commitment aimed at long-term energy independence and sustainability. When you first install your panels, the efficiency is at its peak, and the return on investment (ROI) looks promising. However, as the years pass, you might notice a troubling trend: your electricity bills are creeping up, and your monitoring software shows that while the panels are “working,” they aren’t producing nearly as much power as they used to. While many attribute this to dust, shading, or simple aging, there is a more insidious culprit often at play: delamination.

Delamination is one of the most common and devastating physical defects in solar modules. It is a silent efficiency killer that often goes unnoticed until the damage is extensive. Understanding what delamination is, why it happens, and how to identify it is crucial for anyone looking to maintain the health and longevity of their solar array. In this comprehensive guide, we will dive deep into the mechanics of solar panel delamination and what you can do to protect your investment.

What Exactly is Solar Panel Delamination?

To understand delamination, we first need to understand how a solar panel is constructed. A standard crystalline silicon solar panel is a “sandwich” of several layers bonded together under heat and pressure. These layers typically include:

  • Tempered Glass: The top layer that protects the cells from the elements.
  • Encapsulant (EVA): Usually made of Ethylene Vinyl Acetate, this clear, glue-like layer bonds the glass to the solar cells and the cells to the backsheet.
  • Solar Cells: The silicon wafers that actually convert sunlight into electricity.
  • Backsheet: A polymer layer on the bottom that provides electrical insulation and protection against moisture.
  • Frame: Usually aluminum, which holds the entire assembly together.

Delamination occurs when the bond between these layers—specifically between the encapsulant and the glass or the encapsulant and the cells—begins to fail. When the bond breaks, air and moisture gaps form within the module. While the panel may still be generating a current, its ability to do so efficiently is severely compromised.

Why Efficiency Drops: The Science of Delamination

You might wonder why a simple separation of layers would cause a drop in power output if the silicon cells are still intact. The loss of efficiency due to delamination is caused by several physical and chemical factors:

1. Increased Light Reflection

Solar panels are designed to absorb as much light as possible. The encapsulant layer has an optical index that helps “bridge” the light from the glass to the silicon cell with minimal reflection. When delamination occurs, an air pocket is created. Because air has a different refractive index than the encapsulant or glass, light hits this air pocket and reflects away from the cell rather than passing through to it. This means fewer photons reach the silicon, directly reducing the electrical output.

2. Moisture Ingress and Corrosion

The encapsulant’s primary job is to provide a hermetic seal. Once delamination starts, the seal is broken. This allows moisture and humidity to seep into the internal structure of the panel. Moisture is the enemy of electronics. It leads to the oxidation of the metal busbars and finger lines on the solar cells. Corrosion increases electrical resistance, which generates heat and further reduces the amount of usable electricity that can leave the panel.

3. Increased Internal Temperature

Air is a poor conductor of heat compared to the solid materials in a well-bonded solar panel. When air pockets form via delamination, they act as thermal insulators. This causes the solar cells in those specific areas to overheat. Since solar cell efficiency drops as temperature increases (known as the temperature coefficient), these “hot spots” drag down the performance of the entire string of panels.

The Common Causes of Delamination

Delamination doesn’t happen overnight. It is usually the result of long-term environmental stress or manufacturing flaws. Here are the primary drivers:

Poor Manufacturing Quality

This is perhaps the most common cause of early-onset delamination. If the manufacturer uses low-quality EVA or fails to maintain the correct temperature and vacuum pressure during the lamination process, the bond will be weak from day one. Over time, this weak bond is the first to fail under environmental stress.

Thermal Cycling

Solar panels are subject to extreme temperature fluctuations. During the day, they can reach temperatures upwards of 65°C (150°F), and at night, they cool down significantly. This constant expansion and contraction is known as thermal cycling. Different materials in the panel expand at different rates. If the adhesive/encapsulant isn’t flexible enough or hasn’t cured properly, the mechanical stress eventually tears the layers apart.

UV Degradation

While solar panels are designed to sit in the sun, UV radiation is incredibly harsh. Over 10 to 20 years, UV rays can break down the chemical bonds in the encapsulant polymer. This leads to browning (discoloration) and eventually a loss of adhesion, resulting in delamination.

Extreme Humidity

In tropical or coastal environments, constant high humidity puts immense pressure on the edges of the solar panel. If the edge seals are not perfect, moisture will “wick” into the layers, promoting the separation of the EVA from the glass.

How to Identify Delamination: Visual and Technical Signs

If you suspect your system is underperforming, you should perform a multi-stage inspection. Delamination often leaves “fingerprints” that you can spot if you know what to look for.

Visual Inspection

You don’t always need high-tech equipment to spot delamination. Look for the following:

  • Bubbles: Small or large bubbles appearing under the glass. These are clear signs that the encapsulant has detached.
  • Cloudiness or Fogging: If areas of the panel look milky or foggy, it usually indicates that moisture has entered a delaminated area.
  • Browning/Yellowing: This indicates that the EVA is chemically breaking down, which often precedes or accompanies delamination.
  • Peeling Backsheet: Look at the rear of the panel. If the plastic backsheet is flaking or peeling, the internal layers are likely compromised.

Thermal Imaging (Infrared Cameras)

For a more professional assessment, thermal imaging is used. Because delaminated areas create higher resistance and trap heat, they will show up as “hot spots” on an infrared camera. If you see localized areas of high heat that don’t correspond to external shading, delamination is a likely culprit.

I-V Curve Tracing

Solar technicians use I-V curve tracers to measure the current and voltage of a panel. Delamination typically manifests as a “step” or a “dip” in the I-V curve, indicating that the internal resistance of the module has changed due to layer separation or corrosion.

The Hidden Dangers: Beyond Just Low Efficiency

While a drop in efficiency is the most immediate concern, delamination can lead to more serious problems if left unaddressed. As moisture continues to enter the panel, the risk of Potential Induced Degradation (PID) increases. Furthermore, the localized hot spots caused by delamination can become hot enough to crack the tempered glass or, in extreme cases, cause the backsheet to smolder, posing a fire risk.

From an economic standpoint, delamination destroys the LCOE (Levelized Cost of Energy) of your installation. If a panel meant to last 25 years begins to fail at year 7, the cost per kilowatt-hour of energy produced skyrockets, potentially turning a green investment into a financial loss.

Prevention: Choosing the Right Components

The best way to deal with delamination is to prevent it from happening in the first place. This starts at the manufacturing and procurement stage. If you are a developer or a manufacturer, the choice of adhesives and encapsulants is the most critical decision you will make.

High-quality UV-curable adhesives and advanced EVA formulations are designed to withstand decades of thermal cycling and UV exposure. Ensuring that the materials used have high damp-heat resistance and excellent adhesion to both glass and backsheet polymers is essential.

If you are a consumer, always research the “Tier” of the solar panel manufacturer. Tier 1 manufacturers typically have more rigorous quality control processes and use higher-grade materials that are less prone to delamination. Additionally, check the warranty terms—specifically the “workmanship warranty,” which covers physical defects like delamination, as opposed to just the “power output warranty.”

What to Do if You Find Delamination

If you have confirmed that your solar panels are delaminating, you have a few options:

1. Warranty Claims

Most reputable solar panels come with a 10-to-25-year workmanship warranty. Delamination is considered a manufacturing defect. If your panels are within the warranty period, [Contact Our Team](https://www.incurelab.com/contact) or your original installer to begin the process of a warranty claim. You will likely need photographic evidence and production data to support your claim.

2. Replacement

Unfortunately, delamination cannot be “repaired” in the field. Once the layers have separated and moisture has entered, the structural integrity of the module is compromised. The only effective solution is to replace the affected panels to prevent them from dragging down the performance of the rest of the string.

3. Monitoring

If the delamination is minor and the efficiency drop is negligible, you might choose to monitor the panel closely. However, be aware that delamination is progressive; once it starts, it almost always gets worse over time.

Conclusion: Protecting the Future of Your Energy

Solar energy is one of the most reliable ways to power our world, but it is not “set it and forget it.” Efficiency drops are often a signal that something is wrong beneath the surface. By understanding the risks of delamination, you can take proactive steps to inspect your system, hold manufacturers accountable, and ensure that your panels continue to provide clean, efficient power for their entire intended lifespan.

Whether you are managing a large-scale solar farm or a residential rooftop array, quality matters. From the silicon cells to the adhesives that hold them together, every component plays a role in the longevity of the system. Don’t let delamination steal your ROI—stay vigilant and choose quality from the start.

If you are looking for advanced material solutions or need expert advice on industrial bonding and encapsulation to prevent such issues, we are here to help.

Visit [www.incurelab.com](https://www.incurelab.com) for more information.