“We do not differentiate between the applications; we have all the same grade products for either rooftop or solar parks. However, we help our customers to choose a suitable encapsulant if they have clarity on where the final modules are going to be installed. For example, we always suggest POE and EPE for large-scale projects and EPEEVA for rooftop segments.”
With the rapid shift toward TOPCon, HJT, and bifacial modules, how is Alishan optimising its EVA and POE encapsulant formulations to address PID resistance and long-term degradation?
We have been working on Topcon and all future technology encapsulants for a long time and have developed nearly a dozen products for solving one or other issues related to the new cells and mechanisms. Initially, we were certain that one encapsulant for all will be EPE for mitigating almost all the major degradation modes of Topcon and HJT. However, as we progressed with full-fledged module studies, we understood that different BOM combinations need to be taken care of while optimising the encapsulant. Not only cell surface or metal contacts, but also other small consumables used during the lamination process play an important role in finally deriving the reliability of a module. Keeping almost all the major aspects of lamination and its consequences on the long-term performance, we have tweaked the EVA/POE ratio, introduced special functionality to the layers, reduced acidic environment, mitigated 2nd level non-useful reactions, and so on. To date, we have launched four variants of EPE and a couple of variants of EVA to have both reliable and economically viable modules.
How do your encapsulants perform under high temperature & high humidity conditions typical of Indian climates, and what test protocols do you prioritise to validate field durability?
We have a very stringent quality criteria backed by NABL-approved procedures, and we always work beyond the routine standards of measurements. Our in-house lab is a centre of excellence comprising major and critical testing equipment that is essential for developing new products. We test any encapsulant for DH3000 and UV 165kWh before supplying it as a sample to our customers. We believe that more than PID, DH is a critical test for new technologies and will be a critical tool to differentiate between the encapsulants’ performance.
Can you explain how low-acid EVA improves module reliability, especially in relation to cell metallization corrosion and backsheet compatibility?
Certainly. For more than 30 years, we have all used conventional EVA as a champion encapsulant for all variants of Silicon cells, like polycrystalline, monocrystalline and amorphous. Although yellowing of EVA is very common, its impact on power generation
is still debatable. For Topcon technology, corrosion has become a major source of power degradation, and since EVA is prone to UV-led acidification, we were determined to minimise the acidic environment inside the module. Low acid EVA works well for this purpose by effectively removing/converting the acidic complexes into other non-hazardous reactions. We are yet to see its performance with backsheet modules, but in-house coupon studies show improved optical performance of white and transparent backsheets compared to regular EVA.
What role do in-house testing and accelerated ageing play in shortening product development cycles while maintaining bankability standards?
An in-house R&D laboratory is a vital element to confidently put the product in the market. As mentioned earlier, our lab is equipped with all stage equipments to test starting from raw materials to finished goods. Accelerated testing, like PCT, DH, UV and TC, provides much harsher conditions than the actual environment. These studies help us to understand early/infant and later-stage failures within a few months. We not only test single encapsulants, but also variants with different backsheet models too. This gives us an edge over our competitors to suggest suitable backsheets components to the customers.
How do you balance cost optimisation with performance when developing encapsulants for utility-scale projects versus rooftop or distributed solar applications?
We do not differentiate between the applications; we have all the same grade products for either rooftop or solar parks. However, we help our customers to choose a suitable encapsulant if they have clarity on where the final modules are going to be used. For example, we always suggest POE and EPE for large-scale projects and EPE-EVA for rooftop segments. However, ultimately, customers decide on BOM, and we can hardly trace their choices.
Looking ahead, how is Alishan preparing its material roadmap for next-generation technologies such as tandem cells, glass-glass modules, or thinner wafers?
It will be too early to name the products; however, we have already started for all upcoming technologies in the Indian market, and we will keep pushing a variety of innovative products each year for the sustainable solar installations in India.
