Photovoltaics (PV) has become one of the fastest-growing renewable energy sources. As a core material for module encapsulation, demand for polyester chips for backsheets will continue to rise. In distributed generation, the trend toward lightweight modules may drive the substitution of glass with polyester-based backsheets. Performance optimization and specialization are the key development pathways for these materials.
Global Market Expansion and Net-Zero Goals
The global PV industry is experiencing explosive growth, serving as a primary driver for net-zero emissions. Most nations now prioritize energy transition and carbon neutrality. To achieve net-zero by 2050, 90% of power generation must come from renewables, with solar and wind accounting for nearly 70%. PV systems are projected to surpass all other power sources by 2027.
The 2023 UN Climate Change Conference reaffirmed the 1.5°C goal of the Paris Agreement. The UAE’s “Global Decarbonization Accelerator” (GDA) commits 116 countries to tripling renewable energy capacity to 11 terawatts and doubling energy efficiency rates to 4% by 2030. Success depends on sustained investment in solar PV. In 2023, global cumulative capacity hit 1.6 terawatts, with new installations jumping from 236 gigawatts in 2022 to 446 gigawatts. The PV industry is now a critical engine for a clean, low-carbon society.
PV Module Structure and Encapsulation
PV modules consist of glass, encapsulant film, solar cells, and backsheets. Polyester film backsheets, favored for electrical insulation and weather resistance, are the standard for monofacial modules. Bifacial transparent polyester film backsheets are emerging as a significant future trend, ensuring steady demand for polyester film.
The PV industry chain includes polysilicon production, wafer manufacturing, cell fabrication, module encapsulation, and power generation. A standard module cross-section has five layers: glass, encapsulant, cell, encapsulant, and backsheet. As a vital encapsulation material, the backsheet protects and supports solar cells.
Material Classifications: Organic vs. Inorganic
PV backsheets fall into two categories:
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Organic Polymers: Primarily polyester film backsheets.
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Inorganic Materials: Primarily glass backsheets.
Polyester Film Backsheets
These feature a multi-layer structure. The core is modified PET (polyethylene terephthalate) film, known for high insulation and low moisture permeability. The outer layers typically use weather-resistant fluorinated materials. Manufacturers bond these layers with adhesives or direct coating. A backsheet must provide a moisture barrier, insulation, and weather resistance to ensure cells function in harsh environments. It must also remain stable during lamination and bond securely to the encapsulant.
The “TPT” structure is classic: ‘T’ represents UV-resistant PVF (Tedlar®), and ‘P’ represents the insulating PET film. This structure effectively ensures a 25-year lifespan. Current production processes include lamination, coating, and co-extrusion. Some manufacturers also offer fluorine-free backsheets, which use surface-modified PET to reduce dependence on expensive fluorinated materials.
Glass Backsheets
Glass backsheets create “dual-glass” modules, which are often used in bifacial power generation. Both front and back glass undergo tempering and coating to protect cells and provide structural support. PV glass must achieve over 91.5% light transmittance. Compared to ordinary glass, it has a lower iron content and superior durability.
Cross-section structure of a standard PV module showing polyester backsheet
Module Types and Market Trends
Modules are categorized by generation and structure:
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Generation: Monofacial (back covered with full aluminum) vs. Bifacial (partial aluminum, capturing light on both sides).
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Structure: Single-glass (polyester backsheet) vs. Dual-glass (glass backsheet).
While glass backsheets improve performance in some areas, they increase module cost and weight. Consequently, polyester backsheets remain the mainstream choice for monofacial markets. For bifacial modules, glass backsheets currently lead, but demand for transparent polyester is growing. Compared to glass, transparent polyester backsheets are 90% lighter, easier to install, resistant to salt-alkali corrosion, and handle thermal stress better.
Future Outlook for Polyester Materials
The market’s pursuit of high-power, low-cost modules will phase out outdated capacity. As a core material, polyester for backsheets must improve hydrothermal stability, enhance lamination efficiency, and reduce processing energy consumption.
Polyester chips for backsheets connect chip manufacturers to film producers. Polyester film—produced by biaxially stretching extruded PET chips—is stable and easy to process. It is widely used in printing, electronics, and optical displays. Using it for crystalline silicon cell encapsulation is a vertical expansion into high-end applications.
Polyester chips are a mid-stream product in the polyester chain. Upstream raw materials, PTA and ethylene glycol, undergo esterification and polymerization. Polyester film consumes roughly 30% of these chips. While backsheets protect modules, they are prone to hydrolysis. Industry leaders are now focusing on hydrothermal modification during the chip preparation process. Key strategies include adding end-capping agents to react with terminal carboxyl groups and incorporating titanium dioxide to maintain mechanical strength. In the monofacial market, developing highly reflective polyester film is also essential to boost power generation efficiency.
PET Film for PV Backsheet
As the photovoltaic industry accelerates the shift toward high-efficiency, long-lifespan modules, the demand for superior hydrothermal stability has never been greater. Based on the industry consensus that reducing terminal carboxyl groups is essential to inhibiting hydrolysis, our high-performance Low-Carboxyl Polyester Chips provide the optimal solution.
Engineered to deliver exceptional resistance against heat and moisture, our low-carboxyl chips effectively minimize polymer degradation and enhance mechanical strength, ensuring your backsheets stand the test of time. Partner with Hubei Decon Polyester Co., Ltd to leverage cutting-edge material science for your next-generation PV modules. Contact our technical team today to request data sheets or sample evaluations.
Learn more about our products: https://www.polyestermfg.com/film-grade-pet-chip/
Technical inquiries & sample requests: info@polyestermfg.com
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