The double-glass design enhances resistance to potential-induced degradation (PID) primarily through its hermetic, symmetrical structure that better protects the solar cells from factors that contribute to PID.
Key factors of double-glass design that improve PID resistance:
- Hermetic sealing: The double-glass module structure creates a more hermetic (airtight) environment around the solar cells, which significantly reduces the risk of moisture ingress. Moisture is a key facilitator of PID because it aids the migration of ions, especially sodium ions from the glass, towards the cells. By limiting moisture penetration, the double-glass design inhibits this ion migration, thereby lowering PID risk.
- Symmetrical structure and neutral mechanical stresses: In double-glass modules, the photovoltaic cells are positioned along a neutral axis between two glass layers. This balanced arrangement means the cells experience minimal mechanical tension or compression under load, which reduces the likelihood of microcracks that can exacerbate PID effects. Conversely, conventional glass-backsheet modules have an asymmetrical structure placing cells under tension, increasing mechanical stress and vulnerability to PID-related damage.
- Improved insulation: The glass-glass construction provides better electrical insulation around the cells compared to glass-backsheet modules, further reducing the conditions that typically promote PID.
- Protection from environmental stress: The robust double-glass assembly offers enhanced resistance to external mechanical and climatic stresses (like hail, snow loads, and temperature fluctuations), which indirectly supports better long-term PID resistance by maintaining cell integrity and encapsulation quality.
In summary, the double-glass design combats PID mainly by creating a hermetically sealed, mechanically balanced environment that limits ion migration and moisture ingress, while providing superior insulation and protection from environmental stressors. This collectively results in higher resistance to potential-induced degradation and improved durability of the solar modules.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-double-glass-design-enhance-the-resistance-to-potential-induced-degradation-pid/
