Controlling the optical degradation of , double-glass, n-type monocrystalline solar photovoltaic modules requires a coordinated effort across multiple dimensions, including material selection, process optimization, environmental adaptability design, and operations and maintenance management, to form a comprehensive control system covering the entire module lifecycle. Material selection is fundamental to optical degradation control. In a double-sided, d, both the front and rear covers utilize ultra-clear tempered glass, whose transmittance directly impacts the module's light absorption efficiency. Excessive iron content in the glass reduces transmittance, increasing the risk of optical degradation. Therefore, ultra-clear glass with a low iron content (≤0.015%) is selected, combined with nano-scale anti-reflection coating technology to increase transmittance to over 94%, mitigating initial degradation caused by the glass's inherent properties.
The performance of the encapsulation material is crucial to the module's weather resistance. Traditional EVA (ethylene-vinyl acetate copolymer) readily hydrolyzes in hot and humid environments to produce acetic acid, which corrodes the cell metallization, increasing contact resistance and power degradation. For bifacial, double-glass N-type monocrystalline modules, using POE (polyolefin elastomer) or TPO (thermoplastic polyolefin) as the encapsulation material prevents the release of acidic substances and significantly improves the module's resistance to moisture and heat. Furthermore, the thickness uniformity of the encapsulation material must be controlled within ±0.05mm to prevent local stress concentrations that could cause glass breakage or cell cracking.
Optimizing the cell manufacturing process is key to reducing light-induced degradation (LID). N-type monocrystalline silicon wafers, with their extremely low boron-oxygen complex content, fundamentally reduce the occurrence of light-induced degradation (LID). Doping with gallium instead of boron further suppresses the formation of defect states induced by photogenerated carriers, keeping the first-year degradation rate stable at less than 1%. Furthermore, using laser doping or ion implantation techniques allows for precise control of doping concentration and depth, improving cell uniformity and stability and reducing attenuation variations caused by process fluctuations.
Module structural design must balance heat dissipation and mechanical strength. While the bifacial, double-glass structure improves light absorption efficiency, it also increases the module's weight and thermal capacity. By optimizing the glass thickness (3.2mm front panel + 2.0mm back panel) and frame structure, mechanical load capacity can be maintained while reducing stress caused by differences in thermal expansion coefficients. Furthermore, adding heat sink fins to the back of the module or using high-thermal-conductivity adhesives can effectively lower operating temperatures, slowing the aging of the encapsulation materials and cells, thereby controlling degradation.
Environmental adaptability design requires differentiated strategies for different application scenarios. In high-temperature and high-humidity areas, module power decreases by approximately 0.4% for every 1°C increase in operating temperature. In these situations, increasing the spacing between modules (≥10cm) and optimizing the mounting angle can improve air circulation and reduce the risk of hot spots. In deserts or other windy and dusty areas, wear-resistant anti-reflection coatings and dust-proof glass are required to minimize the impact of dust adhesion on light transmittance. Furthermore, regular cleaning of the module surface is essential to prevent dust accumulation and hard scale, which can lead to localized overheating and increased degradation.
Operation and maintenance management is the last line of defense in degradation control. By establishing comprehensive operation and maintenance records that record every test result, cleaning time, and module replacement, degradation trends can be monitored in real time. Utilize a photovoltaic management system to track power generation, module temperature, and environmental parameters, and use data analysis to provide early warning of potential problems. For example, when an IV curve test indicates module power degradation exceeding a threshold, the cause must be immediately investigated and targeted measures implemented, such as replacing an aging junction box or repairing cracked cells.
Controlling the degradation rate of double-sided, double-glass, n-type monocrystalline solar photovoltaic modules requires a comprehensive approach encompassing materials, processes, design, and maintenance. By optimizing materials such as low-iron glass, weather-resistant encapsulation materials, and gallium-doped cells, combined with environmental adaptability strategies such as heat dissipation design and differentiated protection, and supported by scientific maintenance and management, the module's total degradation rate can be controlled to within 11% over 25 years, significantly improving power generation efficiency and return on investment.
