An entrepreneur planning a new solar module factory in Colombo might focus on securing the right machinery, managing supply chains, and calculating the return on investment. While these are critical steps, an often-underestimated factor can silently undermine the entire operation: the ambient air itself.
In a tropical climate like Sri Lanka’s, high humidity isn’t just a weather condition—it’s a significant technical challenge. If not managed from day one, it can lead to module failure and substantial warranty claims.
This guide breaks down the specific risks high humidity poses to solar module manufacturing. We outline the essential process controls, material choices, and quality checks needed to produce reliable, long-lasting solar panels in such an environment.
Why Humidity Is a Critical Factor in Solar Module Manufacturing
A solar module’s long-term performance depends on its ability to protect sensitive solar cells from the environment for 25 years or more. Moisture is a primary adversary. When water vapor from humid air penetrates a module, it sets off a series of chemical and physical degradation processes.
The most vulnerable stage is lamination, where the module’s layers—glass, encapsulant, cells, and backsheet—are fused under heat and pressure. Trapped moisture can turn into steam during this process, creating bubbles or voids. Over time, this leads to delamination, where the layers separate, compromising the module’s integrity and allowing even more moisture to seep inside.
Persistent humidity also takes a toll on key materials:
- Encapsulant (EVA): The most common encapsulant, Ethylene Vinyl Acetate (EVA), can undergo hydrolysis when exposed to moisture and heat. This chemical reaction produces acetic acid, which is highly corrosive to the solar cell’s metallic contacts and interconnecting ribbons, leading to a gradual loss of power.
- Backsheet: Polymeric backsheets are not perfectly impermeable. Materials with a high Moisture Vapor Transmission Rate (MVTR) allow water vapor to seep into the module over its lifetime. This degrades the backsheet itself, causing it to lose adhesion to the encapsulant.
- Cell Components: Moisture that reaches the solar cells can corrode the solder bonds and the delicate silver grid lines that collect electricity. This results in electrical failures and reduced efficiency.
Key Process Control Points for Humid Environments
Successfully manufacturing solar modules in a high-humidity region like Sri Lanka requires a proactive strategy focused on environmental control, material selection, and process optimization.
Climate-Controlled Environments: Beyond Standard Air Conditioning
The most critical areas of the factory, especially raw material storage and the lamination line, must be protected from ambient humidity. While standard air conditioning provides cooling, it may not be sufficient for moisture removal.
A professional manufacturing setup requires a dedicated HVAC (Heating, Ventilation, and Air Conditioning) system designed specifically for humidity control. The system should maintain a relative humidity (RH) level consistently below 60%. This is typically achieved with industrial dehumidifiers working in tandem with the cooling system. Continuous monitoring with calibrated sensors is essential to ensure these conditions are met around the clock.
Material Selection and Proper Storage
Choosing the right raw materials is fundamental. For tropical climates, it’s crucial to specify materials with a low MVTR, especially for the backsheet and the encapsulant. While these materials may have a higher initial cost, they provide essential long-term protection.
Module design is another key consideration. For instance, understanding the difference between glass-glass and glass-foil solar panels (https://pvknowhow.com/solar-panels/glass-glass-vs-glass-foil-solar-panels-a-comparative-guide-for-manufacturers/) is vital. Glass-glass modules offer superior impermeability to moisture compared to those with a polymer backsheet.
Proper storage protocols are equally important:
- Encapsulant and backsheet rolls should be kept in their original, sealed, moisture-proof packaging right up until they’re needed for production.
- Opened rolls should be used quickly or resealed with desiccants to absorb any ambient moisture.
- All sensitive materials must be stored within the factory’s climate-controlled zone.
Optimizing the Lamination Process
The lamination process is the best chance to remove any residual moisture from the module layup before it is permanently sealed. A lamination cycle consists of heating, pressing, and curing stages, all performed within a vacuum.
In humid climates, adjusting the lamination recipe is often necessary. This usually involves extending the initial heating and vacuum phase (degassing) to allow more time for moisture to be drawn out of the materials before the encapsulant melts and cross-linking begins. A precisely controlled temperature and pressure profile ensures a strong, void-free bond between all layers.
Quality Control and Testing Protocols
Strict, non-negotiable quality control is vital to verify that process controls are effective and that the finished product meets durability standards.
In-Line and Post-Lamination Inspections
Immediately after lamination, every module should undergo a rigorous visual inspection to check for bubbles, voids, or other signs of delamination. However, not all defects are visible to the naked eye.
This is where Electroluminescence (EL) testing becomes essential. It functions like an X-ray for solar modules, revealing hidden defects such as microcracks in the cells. These cracks can be worsened by the mechanical stresses from moisture and temperature cycles, eventually leading to dead areas within the cell.
Advanced Reliability Testing
To validate a module’s long-term resilience against humidity, accelerated lifetime tests are performed on a sampling of modules. The most important of these for tropical climates is the Damp Heat test, specified by the IEC 61215 international standard.
During this test, a module is placed in an environmental chamber and subjected to 85°C and 85% relative humidity for 1,000 hours. This simulates decades of exposure to harsh, humid conditions. A module that passes this test with power degradation of less than 5% has demonstrated that its materials and manufacturing process are robust enough to withstand the climate. This is a core part of the essential guide to solar panel quality control and certifications (https://pvknowhow.com/quality-and-certifications/a-comprehensive-guide-to-solar-panel-quality-control-and-certifications/).
A Sri Lankan Case Study: Lessons from the Field
Based on experience from J.v.G. turnkey projects, a common challenge for new investors is underestimating the need for specialized climate control. One project in a similar Southeast Asian climate initially budgeted for a standard factory ventilation system. During the planning phase, an analysis revealed that ambient humidity levels regularly topped 80%.
The recommendation was to invest in an integrated industrial dehumidification system for the lamination and storage areas. The lamination recipe was also modified with a longer degassing cycle, and a mandatory Damp Heat test was instituted for each production batch. While this increased the initial capital expenditure by a small percentage, it has resulted in a product with a very low field failure rate and a strong reputation for reliability in the local market, ultimately protecting the long-term business case.
Frequently Asked Questions
What is the ideal humidity level for a solar module production area?
For critical areas like raw material storage, lay-up, and lamination, the relative humidity should be maintained below 60%. Continuous monitoring is vital to ensure this target is consistently met.
Can standard air conditioning control humidity effectively?
Not always. Standard air conditioning is designed primarily for cooling and may not remove enough moisture to reach the sub-60% RH level, especially during monsoon seasons. Industrial dehumidifiers are often a required investment.
Are glass-glass modules a better choice for humid climates?
Glass-glass modules generally offer superior long-term protection against moisture ingress because glass is an almost perfect barrier to water vapor. This makes them an excellent technical choice for tropical environments, though the decision also involves factors like cost and weight.
How does humidity impact a module’s power output?
Humidity does not typically affect the initial power output measured at the factory. Its impact is on long-term reliability. The degradation it causes through corrosion and delamination leads to a gradual and premature loss of power over the module’s service life, resulting in warranty claims and reputational damage.
Building for Longevity in a Tropical Climate
For entrepreneurs entering the solar manufacturing sector in Sri Lanka, mastering the humidity challenge is a prerequisite for success. It’s a manageable risk, but one that requires a dedicated focus from the earliest stages of factory planning through daily operations.
Addressing this factor proactively—by designing the right building infrastructure, selecting robust materials, and implementing stringent quality checks—is far more cost-effective than dealing with widespread product failures down the road.
By acknowledging and engineering for local climatic conditions, a new manufacturing venture can build a strong foundation for producing high-quality solar modules that will perform reliably for decades. For those just beginning, exploring the complete process of starting a solar panel factory (https://pvknowhow.com/how-to-start-a-solar-factory/how-to-start-a-solar-panel-factory-a-complete-guide/) provides a structured overview of all the necessary steps.
