Silicone gel encapsulants are transforming the photovoltaic (PV) industry by addressing the weaknesses of traditional EVA-based encapsulation. With over six decades of proven performance in space, concentrator systems, and harsh climates, silicone gels ensure superior durability, efficiency, and recyclability.
Despite its widespread use, ethylene-vinyl acetate (EVA) encapsulant has shown multiple long-term reliability issues in real-world PV panel operations.
| Failure Type | % of Total Failures |
|---|---|
| Corrosion | 45.3% |
| Cell or Interconnect Break | 40.7% |
| Output Lead Problem | 3.9% |
| Junction Box Problem | 3.6% |
| Delamination | 3.4% |
| Overheated Wires/Diodes | 1.5% |
| Mechanical Damage | 1.4% |
| Defective Bypass Diodes | 0.2% |
🔴 Key Insight:
Nearly 86% of EVA-related failures are due to corrosion and interconnect breakage—problems strongly linked to EVA’s degradation into acetic acid under UV and thermal stress.
VIESH Research Institute pioneered the manufacturing of vacuum glazing with thermoplastic spacers, filling evacuated cavities with optically transparent polysiloxane compounds.
Recently, VIESH Institute and Traxle Solar Company scaled this technology to an industrial level, enabling production capacity suitable for multi-MW PV panel manufacturing plants.
| Feature / Property | EVA Encapsulant | Silicone Gel Encapsulant |
|---|---|---|
| Long-Term Operating Temp. | -40 to +80°C | -60 to +250°C |
| UV Radiation Resistance | Low | High |
| Operating Lifetime | ~25 years | ~40 years |
| Laminator Energy Use (per hr) | 49 kWh | 4.5 kWh |
| Refractive Index | 1.482 | 1.406 |
| Transparency @ 360 nm | 8% | 90% |
| Transparency @ 400 nm | 62% | 91% |
| Transparency @ 600–1000 nm | 91% | 93% |
| Corrosive Agents (Lamination) | Acetic Acid Released | None |
| Corrosive Agents (Ageing) | Acetic Acid Released | None |
| Mechanical Stress (Lamination) | Yes | No |
| Mechanical Stress (Ageing) | Yes | No |
| Lamination Temperature | +130°C | +20°C |
| Modulus of Elasticity | 10.0 N/mm² | 0.006 N/mm² |
| Thermal Expansion Coefficient | 4.0 × 10⁻⁴ K⁻¹ | 2.5 × 10⁻⁴ K⁻¹ |
Extended Lifetime – 40+ years vs ~25 years for EVA.
High Optical Transparency – Improves conversion efficiency (up to +15% energy yield over lifetime).
Thermal & UV Stability – Withstands extreme environments, from deserts to high-altitude climates.
No Corrosive By-Products – Unlike EVA, which degrades to acetic acid.
Low Energy Manufacturing – ~10x lower lamination energy requirement.
Mechanical Stress-Free – Gel structure absorbs expansion/contraction stresses.
Recyclability – Panels laminated with silicone gel are easier to recycle and recover.