SOLYCO HJT modules | Additional butyl seal for improved moisture protection

Handmuster: Butyl-Abdichtung für verbesserten Feuchtigkeitsschutz bei Solarmodulen

SOLYCO heterojunction double-glass modules (HJT) ( R-BG 108h.5 & R-TG 96h.5 ) feature an additional butyl seal at the module edges to optimize the long-term reliability and moisture resistance of the modules. This is not merely a marketing gimmick, but a technical solution to the specific physical challenges of modern high-performance modules. But what advantages does this additional butyl seal actually offer?

Protection against moisture penetration

Solar modules with tempered front and back glass offer a high level of protection against mechanical and climatic influences. Basic moisture protection is already ensured by the encapsulation materials used within the laminate. However, the module edges represent a particularly critical area due to their design, as different materials meet here. Suitable edge sealing with butyl in heterojunction modules helps to minimize moisture penetration into the laminate structure and effectively limit potential aging mechanisms such as corrosion, delamination, or electrical degradation.

Properties of butyl sealant

1. Moisture barrier:

Butyl rubber (polyisobutylene) forms a virtually hermetic seal at the edges, significantly reducing the ingress of water vapor and air. This is particularly important for glass-to-glass or frameless modules, where there are no metal frames that would otherwise be protected.

2. Flexible & durable:

Butyl remains flexible for decades (approximately from -40 °C to +120 °C) without becoming brittle or cracking. This flexibility is crucial for withstanding thermal cycles (day-night fluctuations) and maintaining watertightness throughout the module's lifespan. Studies and field tests show that modules with high-quality edge sealing typically operate 10-15 years longer without significant performance losses than those without such sealing.

3. Improved electrical insulation:

Butyl can also contribute to electrical insulation and prevent voltage breakdowns at the module edges - important in systems with higher operating voltages (up to 1500 V or more).

Combination with other materials

Butyl edge sealant is never used alone, but always in conjunction with high-quality POE-containing embedding materials (instead of conventional EVA), which themselves have very low moisture permeability and do not produce acid-forming byproducts. This combination results in a significantly extended service life and considerably reduces the risk of PID (potentially induced degradation). Thanks to the enhanced moisture protection, a guaranteed residual performance of over 90% can be assured even after 30 years of operation.

Summary

Aspect	Effect of butyl edge sealing
Moisture protection	It blocks water vapor at the module edges.
Thermal stability	Remains flexible across wide temperature extremes
Corrosion protection	Reduces metal corrosion and PID risks
life	Significantly extends module lifespan
synergy	Works particularly well with POE encapsulants