The photovoltaic industry, a key player in the solar power generation sector due to the growing global demand for renewable energy, has developed rapidly. As the main components of the solar energy conversion process, photovoltaic panels directly influence the efficiency and lifetime of solar power systems. Photovoltaic films are crucial in the production of solar cells as they protect, encapsulate, and enhance the performance of the cells. This article examines the history of photovoltaic films, the types of films available, the material structures, and the applications of hydrolysis-resistant carbodiimide agents in PV PET films and anti-PID masterbatches for encapsulant films.

1. The Structure and Types of Photovoltaic Films

A photovoltaic module is primarily composed of photovoltaic cells, glass, a backsheet, and encapsulant films. Photovoltaic cells convert solar energy into electricity and are classified primarily into thin-film and crystalline silicon solar cells. Due to their high conversion efficiency and mature production processes, crystalline silicon cells are widely used in modern photovoltaic technologies.

Film materials are essential for encapsulating photovoltaic cells. Backsheet films, protective films, and encapsulant films are all types of photovoltaic films. Backsheet films protect photovoltaic cells from environmental factors such as UV radiation, moisture, and oxidation, ensuring their stability and efficiency. Backsheet films are commonly made from polyester (PET), polyolefins (PO), and polycarbonates (PC). Encapsulant films, on the other hand, encapsulate the photovoltaic cells and other components to ensure the stability and durability of the cells. Encapsulant films are commonly made from EVA or PVB.

2. The History of Photovoltaic Films

The development history of photovoltaic films is closely linked to the advancement of photovoltaic panels. Early photovoltaic films were made from simple materials designed to protect the photovoltaic cells from external environmental influences. These early films were not durable and were prone to degradation and aging when exposed to moisture and UV radiation.

With continuous advancements in photovoltaic technology, the materials used for photovoltaic films evolved to offer better performance. Transparent backsheet films, moisture-resistant films, and other innovations in the 1990s improved the durability and stability of films. In the 21st century, with the rapid development of the photovoltaic sector, high-performance films became mainstream. Key characteristics such as hydrolysis resistance, UV resistance, and PID resistance became essential for the performance of photovoltaic films.

3. Materials and Types of Photovoltaic Films

In addition to material properties, environmental conditions and costs are important factors in selecting photovoltaic films. Polyester (PET), polyolefins (PO), polyurethanes (PU), and polycarbonates (PC) are the primary materials used for photovoltaic films. Each material has its advantages and disadvantages.

• PET Film: Polyester films are widely used in photovoltaic applications due to their excellent mechanical properties and UV resistance. PET films are relatively low-cost and produced through well-established processes, making them ideal for large-scale manufacturing. However, their hydrolysis resistance is relatively low, which can lead to aging problems in humid environments.
• Polyolefin (PO) Film: Polyolefin films offer excellent flexibility, high-temperature resistance, and chemical stability. Compared to PET films, PO films offer better hydrolysis resistance, making them ideal for high-moisture and high-temperature environments.
• Polyurethane (PU) Film: Polyurethane films have excellent chemical resistance and mechanical strength. Their durability makes them ideal for high-performance applications, though they are more expensive than other film types.
• Polycarbonate (PC) Film: Polycarbonate films are suitable for photovoltaic panels that require high performance and temperature resistance, providing superior strength and heat resistance.

4. Use of Carbodiimide-Based Hydrolysis-Resistant Agents in PV PET Films

Carbodiimide-based hydrolysis-resistant agents are widely used in photovoltaic PET films to enhance their hydrolysis resistance. These hydrolysis-resistant agents work by chemically interacting with water molecules, preventing the water from interfering with the PET film’s molecular structure, thereby improving its resistance to hydrolysis. The stabilizing effect on the film’s molecular chains prevents water-induced degradation and aging, thus extending the lifespan of the photovoltaic panel. In addition, carbodiimide agents improve the reliability of photovoltaic panels in high-moisture environments and reduce power degradation rates.

5. Use of Anti-PID Masterbatches in Encapsulant Films

The PID (Potential Induced Degradation) effect is a common degradation that occurs in photovoltaic cells over time. PID causes current leakage within the cells, leading to reduced cell efficiency and, in some cases, system failure. Anti-PID masterbatches are increasingly being used in photovoltaic encapsulant films to prevent PID effects.

Anti-PID masterbatches work by adding specific chemical components to the encapsulant film, which suppress current leakage. By optimizing the electrical properties of the encapsulant films, anti-PID masterbatches improve the stability of photovoltaic systems and enhance their resistance to degradation. The addition of anti-PID masterbatches improves the performance of photovoltaic panels in high-temperature and high-moisture environments, thus increasing their reliability and longevity.

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6. Future Development Challenges and Directions

Research and applications of photovoltaic films are continuously evolving as the photovoltaic industry advances. Future photovoltaic films are expected to be more efficient, longer-lasting, and cost-effective. Smart photovoltaic films, self-healing films, and high-efficiency films are expected to become major trends. The application of new materials such as thin-film technologies and quantum dot technologies presents additional opportunities for improving the performance of photovoltaic films.

However, the development of photovoltaic films still faces several challenges. High-performance films are still relatively expensive to produce, and reducing these costs without compromising performance remains a significant challenge. Additionally, the environmental impact of photovoltaic films is a concern, with recycling and reusing film materials being key to the sustainable growth of the photovoltaic industry.

7. Conclusion

Photovoltaic films play a vital role in the performance and longevity of photovoltaic panels. The type, material structure, and performance of these films directly impact the durability and efficiency of the panels. Technological advancements have significantly improved the performance of photovoltaic films, particularly with the use of hydrolysis-resistant carbodiimide-based agents and anti-PID masterbatches. As the industry progresses, photovoltaic films will continue to evolve towards more efficient, environmentally friendly, and high-performance materials, driving the sustainable growth of the photovoltaic sector.