HIUV classifies its EVA encapsulants based on their placement in the module: S201MT1 for the glass side, S201MT2 for the rear side, and S201W as a white rear encapsulant
S201MT1 features a thinner 420 μm profile and is wider at 1,096 mm, while maintaining standard optical and mechanical properties
Rear-side encapsulants offer protection against UV wavelengths below 360 nm and offer strong PID suppression
The 2024/25 TaiyangNews Backsheets and Encapsulation Market Survey, the 4th edition in the series, highlights insights from key industry players in the segment. HIUV, a leading company in the encapsulation segment, has provided data for 3 models, each with specific applications. The company actually differentiates applications at the product level based on the layer they are applied to in the module wrap, and the products have undergone a few changes. S201MT1 is specially designed for the glass side of the laminate. It is now offered in a standard thickness of 420 μm instead of 450 μm, and is wider at 1,096 mm. As with all other EVA suppliers, HIUV offers a wide range of dimensions suitable for any special requirements. The density is given as 0.96 g/m3.
S201MT2 is promoted for rear-side encapsulation. Similar to the other models, it also comes with a surface finish of double-frosted and pyramid embossing to enhance the light trapping. In terms of mechanical properties, the specs for this model and the S201MT1 described above are the same. Both have a tensile strength of ≥ 18 MPa and ≥ 500% elongation in both MD and TD directions, while shrinkages are ≤ 2% and ≤ 4% in the respective directions. The bonding to glass is ≥ 60 N/cm, which is only relevant for glass-glass modules, and a backsheet adhesion strength of ≥ 50 N/cm. They are also identical in terms of performance attributes – limiting water vapor absorption to less than 0.1% in weight, a volume resistivity of ≥ 1x1015 Ohm.cm, and a refractive index of 1.48. As with the front EVA S201MT1, this rear encapsulant is also transparent, and both are rated with a light transmittance of 91% in a wavelength band of 380 to 1,100 nm. However, this EVA, placed at the rear of the laminate, is designed to protect UV exposure below 360 nm. These 2 complementary products exhibit ‘good PID suppressing properties’ according to HIUV (see Encapsulation Sector Balancing Innovation And Cost Pressures In Solar).
S201W is also designed for the rear side, but it is a white EVA that helps enhance the module’s optical performance. The films supplied under this label are specially treated with electron beam pre-crosslinking technology to avoid any overflow of white pigment onto the front side. This product comes with a different tensile strength of ≥ 16 MPa. Like the other 2 encapsulants, this product also belongs to the fast-cure class, meaning the processing conditions are the same for HIUV’s entire product range. The EVA product range supports laminating temperatures of 140 to 170°C. As for the lamination cycle time, 5 to 7 minutes is recommended for vacuum, with 9 to 11 minutes of press time. The crosslinking is accomplished in a temperature window of 135 to 150°C. The film has a vinyl acetate content of 28.5% and 80 to 95% gel content. This EVA model comes with a slightly lower volume resistivity of ≥ 1 × 1014 Ohm.cm (see Optimizing Encapsulation For Next-Gen Solar Modules).
At the TaiyangNews High-Efficiency Solar Technologies 2024 Conference, Jitin Rai Khanna, Global Sales Director at HIUV, shared insights on the company’s latest encapsulation solutions tailored for TOPCon modules (see Advancements In TOPCon Technology: HIUV’s Encapsulants).
The text is an excerpt from the latest TaiyangNews Market Survey on Backsheets & Encapsulation Materials 2024/25, which can be downloaded for free here