The service life of photovoltaic modules is usually required to be more than 25 years. As a "protective shield" against external environmental erosion, packaging technology directly determines the long-term reliability and power generation stability of modules. With the rapid development of new battery technologies such as perovskite and ultra-thin silicon, packaging technology not only needs to cope with traditional challenges such as water vapor, ultraviolet radiation, and temperature cycles, but also needs to adapt to the material characteristics of new batteries, becoming a key support for the industrialization of photovoltaic technology.

Water vapor penetration is the primary factor leading to the failure of photovoltaic modules, and it is particularly fatal for perovskite batteries—trace water vapor can cause the decomposition of perovskite materials, leading to a sharp decline in efficiency. The water vapor transmission rate of traditional packaging materials is mostly at the level of 10⁻³g/m²/day, which is far from meeting the needs of high-efficiency batteries. The breakthrough of organic-inorganic composite packaging technology has changed this situation. By combining the compactness of the inorganic barrier layer with the flexibility of the organic adhesive layer, the water vapor transmission rate is reduced to below 10⁻⁵g/m²/day, providing reliable protection for sensitive materials such as perovskite.

Ultraviolet radiation is another important aging factor. Long-term irradiation can cause the packaging film to turn yellow and become brittle, which not only reduces light transmittance but also destroys the internal structural integrity of the module. The construction of the anti-ultraviolet packaging system starts from two aspects: one is to add high-efficiency ultraviolet absorbers and stabilizers to the film to convert ultraviolet light into harmless energy; the other is to use high-transmittance quartz glass or tempered glass treated with ultraviolet coating as the cover plate, which filters more than 90% of harmful ultraviolet bands while ensuring the visible light transmittance exceeds 94%.

Extreme temperature cycles put forward strict requirements on the sealing performance of the packaging structure. In the alternating environment of low temperature (-40℃) and high temperature (85℃), the difference in thermal expansion coefficients of different materials can easily lead to interface peeling, lead breakage and other problems. The application of elastic packaging materials effectively alleviates this contradiction. The thermal expansion coefficient of this type of material can be accurately matched with the battery sheet and cover plate materials, and it can still maintain good bonding performance when the temperature changes drastically. Combined with the wide temperature range adaptability of the edge sealant, the power attenuation rate of the module under extreme working conditions is controlled within 0.1% per month.

In response to the special needs of flexible modules, flexible packaging technology has also achieved synchronous development. Using polyimide (PI) or ethylene-tetrafluoroethylene copolymer (ETFE) as the flexible substrate, combined with special flexible films, the packaged modules can withstand more than 100,000 bending cycles while maintaining excellent weather resistance, providing a guarantee for the outdoor application of flexible photovoltaics.

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