Research on the Types and Characteristics of Photovoltaic Module Packaging Adhesive Films

Introduction: In solar photovoltaic power generation systems, photovoltaic modules are one of the key components. The encapsulation film is an indispensable part of photovoltaic modules, located between the battery cells and glass, as well as between the backplate and aluminum frame, which protects the battery cells from external environmental erosion and improves the photovoltaic conversion efficiency of the modules. This article will delve into the types and characteristics of photovoltaic module packaging films, in order to provide reference for relevant professionals in the industry. The classification of packaging films for photovoltaic modules is mainly divided into three categories based on different materials: EVA (ethylene vinyl acetate copolymer) film, POE (polyolefin elastomer) film, and other new material films. （1） EVA film features: advantages: lower price; Has good adhesion and processing performance; It can effectively block the damage of ultraviolet rays to battery cells. Disadvantages: Poor weather resistance, easy yellowing after long-term use, affecting light transmittance; The ability to resist PID (potential induced attenuation) is weak. Applicable scenario: Suitable for ordinary monocrystalline silicon or polycrystalline silicon battery components. （2） Characteristics of POE film: Advantages: excellent aging resistance and long service life; Excellent water vapor barrier effect, preventing water vapor from entering the interior of components and causing corrosion; Strong resistance to PID. Disadvantage: High cost; Due to its high molecular weight, it is easy to encounter issues such as foggy appearance or uneven surface tension during the processing. Applicable scenarios: Suitable for double glass modules, N-type high-efficiency battery modules, and occasions with higher reliability requirements. （3） With the development of technology, some new packaging materials have gradually been developed, such as TPU (Thermoplastic Polyurethane Elastomer) film for other new materials. These new materials typically combine the advantages of EVA and POE, and perform better under certain specific conditions. The technical parameters of packaging film When selecting a suitable packaging film, a series of technical indicators need to be considered, mainly including the following aspects: transmittance: directly affects the photoelectric conversion efficiency of the component, usually requiring an initial transmittance of not less than 90%, and a retention rate of over 85% after long-term outdoor use. UV resistant linearity: resist the degradation effect of ultraviolet rays, ensuring the service life of the adhesive film. Moisture and heat resistance: Maintain stability in high temperature and humid environments to avoid delamination or performance degradation. Low temperature resistance: Maintain flexibility and adhesion in low temperature and condensing environments. Peel strength: Ensure a strong connection between the adhesive film and the substrate, and prevent moisture penetration. Volume resistivity and interface resistivity are particularly important for double-sided components, as they relate to their electrical performance and safety. Fire rating: Meet the requirements of different countries and regions for building safety materials. The selection of packaging film for photovoltaic modules not only affects the performance and service life of the modules themselves, but also relates to the stability and economy of the entire photovoltaic system. Therefore, in practical applications, multiple factors need to be comprehensively considered, including cost, environmental conditions, component types, and specific customer needs, in order to make the best decision. In the future, with the advancement of technology and the development of new materials, it is believed that more high-performance and environmentally friendly packaging films will emerge, promoting the sustainable development of the photovoltaic industry.