In recent years, the performance changes (UVID) of n-type silicon solar cell modules under ultraviolet light irradiation have attracted attention. In June 2024, a report released by the US RETC Photovoltaic Testing Laboratory showed that in multiple photovoltaic projects, the spontaneous glass breakage rate of modules reached 2%-5%, which is a new type of photovoltaic failure. Ultraviolet light irradiation can cause light-induced decay, spectral response changes and irradiation damage of n-type silicon solar cells, affecting their electrical properties and efficiency. In order to verify the performance changes of photovoltaic modules after long-term ultraviolet light exposure, Millennial UV Preconditioning Chamber has become a key equipment to test the durability of polymer materials such as EVA, silicone, and backplanes to ensure that they comply with IEC61215 and IEC61730 technical standards.

Ultraviolet light degradation (UVID) of n-type modules

The ultraviolet light degradation (UVID) of n-type modules mainly involves the performance changes of n-type silicon solar cells under ultraviolet light. In June 2024, the US RETC Photovoltaic Testing Laboratory released the preliminary report of the 2024 PV Module Index Report. According to the investigation, several large-scale utility photovoltaic projects with a capacity of about 100MW to 300MW collected on-site by RETC had a spontaneous glass breakage rate of 2%-5%. Teresa Barnes, head of the NREL Photovoltaic Reliability and System Performance Group, said that spontaneous glass breakage is "a photovoltaic failure that has never been seen before." Historically, this type of glass breakage is usually due to shoddy operation and maintenance or bad luck such as scratching rocks, as well as poor quality thin-film photovoltaic modules. However, it is no longer surprising that glass breaks in crystalline silicon modules.

UV degradation (UVID) of n-type modules mainly involves the performance changes of n-type silicon solar cells under ultraviolet light. From the report, it can be seen that modern solar cell architectures, including n-type modules, are more sensitive to UVID.

Conversion Efficiency

RETC captures PV module conversion efficiency data as part of its manufacturer's CEC testing. The nominal conversion efficiency is determined by dividing the maximum rated power of the product under standard test conditions by its total aperture area. Conversion efficiency is a key benefit of PV modules.

According to the report, the currently popular p-type passivated emitter rear contactor (p-PERC) PV cells provide better initial efficiency at time zero compared to traditional aluminum back surface field (Al-BSF) technology. Meanwhile, n-type tunnel oxide passivated contact (n-TOPCon) and n-type silicon heterojunction (n-HJT) PV cell technologies provide manufacturers with a roadmap for future even higher efficiency product designs.

Performance changes of n-type silicon solar cell modules under ultraviolet light irradiation

Light-induced attenuation phenomenon: According to research, n-type crystalline silicon solar cells will cause a large amount of fixed charges to accumulate at the SiN:H/Si interface of the surface anti-reflection film under light, increase the density of interface states, and destroy the passivation layer structure on the surface of the battery. This results in a large attenuation of open circuit voltage and short circuit current. For example, the efficiency of n-type silicon solar cells decreases by 3.6% after 35 kWh/m^2 light irradiation.

Changes in spectral response: UV-visible spectrum analysis shows that gamma irradiation can cause discoloration of conductive glass, causing the transmittance of the glass to decrease. Although this is a study on dye-sensitized solar cells, UV light irradiation may also affect the transmittance of n-type silicon solar cells, thereby affecting their performance.

Radiation damage effect: Radiation damage effect is applicable to n-type silicon solar cells. The increase in electron irradiation dose will lead to a significant decrease in electrical parameters such as short-circuit current density and maximum output power of the battery. At low dose rates, the maximum power of the battery dropped by 40% when the dose reached 200 kGy.

UV Preconditioning Chamber

E-mail: market@millennialsolar.com

It is mainly used to test the polymer materials such as EVA, silicone, backplane, junction box and cables in the battery packaging structure of solar modules. The performance of these polymer materials will change after long-term ultraviolet light exposure. UV Preconditioning Chamber is designed to verify the performance changes of solar modules after ultraviolet light exposure.

·Mainly used to test the performance of polymer materials of photovoltaic modules

·Multifunctional and customizable

·Compliant with IEC61215; IEC61730

In summary, the performance change of n-type silicon solar cell modules under ultraviolet light is an important factor affecting their long-term reliability. With the continuous development of photovoltaic technology, it is particularly necessary to conduct in-depth research on the performance of modules under different environmental conditions. As a key testing equipment, UV Preconditioning Chamber provides a scientific basis for evaluating the durability of polymer materials of photovoltaic modules to ensure that they meet international technical standards. In the future, by optimizing module materials and manufacturing processes, the anti-ultraviolet light decay performance of n-type silicon solar cells can be further improved, providing a solid guarantee for the sustainable development of the photovoltaic industry.