If you are familiar with the structure of a PV module, you may know the crucial role encapsulants play in the long-term performance of the module. Encapsulants act as a protective layer between the solar PV cells and the environment, providing electrical insulation, weather resistance, and impact resistance.
Among the various encapsulant options—such as EVA (Ethylene Vinyl Acetate), POE (Polyolefin Elastomer), and EPE (EVA-POE-EVA)—selecting the best one is no easy task for a module manufacturer.
However, after extensive research, testing, and field performance monitoring, we conclude that POE stands out as the most superior encapsulant for n-type TOPCon modules.
What is POE?
POE encapsulant is made from POE resin, a thermoplastic elastomer that combines the properties of rubber and plastic. This resin is modified with various processes and additives to make it suitable for encapsulating solar PV cells.
Why is POE popular?
Let’s understand the key reasons behind the rising popularity of POE encapsulants:
Superior moisture barrier
POE encapsulants have a lower water vapour transmission rate (WVTR), making them less likely to allow moisture to penetrate the solar panel and harm the cells. This quality is particularly beneficial for moisture-sensitive n-type PV cells, ensuring long-term protection and module reliability.
No acid formation
Unlike EVA, POE does not produce acetic acid. This characteristic makes POE an excellent choice for Glass-Glass (G-G) modules. In G-G modules, the non-permeable structure can trap any acids formed from encapsulant degradation, potentially damaging the cells and connections through chemical interactions. POE eliminates this risk, preventing issues like blackening and corrosion.
High PID resistance
Potential-induced degradation (PID) is a phenomenon that can lead to power losses in solar panels in hot and humid climates. POE encapsulants exhibit high PID resistance, making them a preferred option for G-G modules. These modules often contain free sodium ions that can cause high leakage currents, but POE helps mitigate this issue, ensuring consistent performance.
Are all POE encapsulants the same?
The answer is a clear NO.
Recent studies have shown variability in the performance of POE encapsulants from different manufacturers. For instance, researchers at the University of New South Wales found that some POEs performed poorly, leading to significant degradation in n-type TOPCon modules. This degradation was attributed to the release of certain additives from the POE, which reacted with the soldering flux and cell metallization, causing contact corrosion. However, it's important to note that this degradation was only observed in POEs from specific manufacturers.
A report by pv Europe highlights research that strongly supports the use of POE encapsulants, particularly in modules using n-type solar cells, such as TOPCon.
RenewSys: Leading the Charge in POE Encapsulants
RenewSys, India's largest PV Encapsulant and Backsheet manufacturer, has been at the forefront of introducing innovative encapsulant solutions. We were the first manufacturer to introduce POE Encapsulant in India in 2018 and POE Encapsulant tailored for TOPCon modules in 2023. Moreover, RenewSys houses India’s first NABL-accredited testing lab for encapsulant and backsheet and their raw materials at its manufacturing facility in Bengaluru.
RenewSys’ N-type TOPCon module series uses POE Encapsulants on both sides. Check module datasheet here.
In July 2024, our POE encapsulant, CONSERV E-360, received high praise from the Fraunhofer Institute for Solar Energy Systems ISE, Europe's largest solar research institute. Their tests confirmed that modules made with our POE were bubble-free and exhibited excellent crosslinking under various lamination conditions.
While POE encapsulants show great promise, research and testing are ongoing to fully understand their long-term performance.
Data source:
RenewSys R&D
Image source:
RenewSys