Sep. 19, 2025
Curved crystalline silicon PV tiles are a BIPV product that deeply integrates crystalline silicon photovoltaic cells with traditional solar roof tiles. Compared to conventional solar panel, curved crystalline silicon PV tiles are designed to preserve the curves and aesthetics of traditional building roofs while achieving efficient power generation and long-term weather resistance.
Making crystalline silicon into "curved PV tiles" that can withstand the curvature of roofs maximizes power generation efficiency per unit area while preserving the building's original form and aesthetics.
Based on this demand, curved crystalline silicon PV tiles face two technical challenges:
1. How can the inherently brittle crystalline silicon material be processed into a structure that adapts to curved building surfaces while preventing silicon wafer cracking and maintaining electrical performance?
Crystalline silicon cells currently lead in efficiency and stability, but the rigid sheet structure of traditional crystalline silicon cells makes them difficult to directly adapt to curved roofs. Typically 150–200 microns thick, they offer little flexibility. Conventional photovoltaic modules are flat, rectangular panels, making them difficult to use directly in applications like curved roof tiles and curved roofs.
Once subjected to bending stress exceeding critical limits, traditional silicon wafers are prone to microcracks or even breakage. To adapt the silicon wafers to curved surfaces, they must either be made ultra-thin (reducing stiffness) or employ specialized cutting/thinning/peeling processes. Even if the silicon wafers are successfully bent, the laminated module must be able to withstand outdoor temperature cycles, wind loads, snow pressure, and other factors, otherwise they are prone to failure.
2. How can we minimize the loss of photovoltaic cell efficiency and maintain long-term stability while achieving a colored or semi-transparent appearance?
Building photovoltaics (BIPV) not only need to generate electricity but also meet aesthetic requirements (color and light transmittance), such as glass curtain walls and colored roofs. Color results from selective reflection or absorption of light, which inevitably reduces the effective light reaching the silicon wafer. Furthermore, the higher the transmittance of solar tiles, the less light reaches the cell, resulting in lower power generation and conversion efficiency. Color coatings or microstructures must be uniform over large areas, resisting fading due to aging or environmental changes, while also ensuring the long-term reliability of the modules.
Transforming crystalline silicon photovoltaics from being limited to square panels to being able to integrate with architectural forms; transforming photovoltaic modules from being "blackboards" into a diverse architectural material option that meets aesthetic and design needs, ensuring both aesthetic appeal and stable power generation, is a key development direction for BIPV.
Since its establishment in 2007, Yingli|Gain Solar has been focused on the research and development and industrialization of BIPV technology, committed to promoting the deep integration of green buildings and clean energy. Leveraging the National Key Laboratory of Photovoltaic Materials and Photovoltaic Cells, it has established multiple R&D platforms, including the Photovoltaic Green Building Materials Research Center and the Hebei Province Photovoltaic Building Integration Technology Innovation Center. With a cumulative investment of nearly 1 billion yuan, Gain Solar has successfully overcome the production challenges of curved crystalline silicon panels and the bottlenecks in color transmission efficiency, developing the world's first curved crystalline silicon photovoltaic tile, filling a gap in the international field. Its unique ultra-thin curved crystalline silicon technology and multi-colorization technology have reached internationally advanced levels.
Ultra-Thin Silicon Wafers: Crystalline silicon cell thickness is significantly reduced from the conventional 150–200 µm to a few microns, allowing the wafers to achieve a certain degree of flexibility, allowing them to conform to curvature or undergo localized shaping. Ultra-thin silicon cell thinning is achieved through mechanical grinding/chemical wet polishing (chemical etching), backside thinning, and thin-film transfer/stripping.
Mechanical Strengthening and Stress Management: Ultra-thin silicon wafers are prone to microcracks during the molding and installation processes. Mechanical supports are designed at the module level to absorb bending stress, combined with optimized cell structure to distribute stress and reduce the risk of fracture.
Maintaining Electrical Performance: Significant wafer thinning changes surface recombination, backside reflection, and light absorption pathways. To maintain or improve conversion efficiency, simultaneous optimization of surface passivation, backside optical enhancement, and optimized electrode and gridline design are performed to minimize performance loss.
Digital glass printing/Ceramic frit: Color printing or glazing is applied to the surface glass of a module to create a multi-color or textured effect. Light transmission can be controlled through shading patterns, while selectively affecting the spectrum.
Thin film/mineral coating: Thin films (such as dielectric reflective layers, nanostructured layers, or metal/dielectric composite layers) are deposited on the encapsulating glass or cell surface to produce controllable color through interference or plasmon effects. Energy loss to incident light can be minimized through design.
Selective texture and microstructure: Surface microstructure design (micro-nanotexture or textured glass) can be used to create specific scattering or reflection characteristics in the visible light band, thereby creating color and a sense of translucency, while minimizing absorption within the photovoltaic effective band.
Gain Solar's Curved Crystalline Silicon and Color Transparent Technology Breakthrough Comparison Table
Technical Direction | Technical Bottlenecks | Gain Solar's Technological Achievements |
Production of Curved Crystalline Silicon Surfaces | Crystalline silicon is thick, brittle, and cannot be bent. It will break if subjected to excessive stress. Processing and packaging are difficult, making it difficult to conform to curved roof surfaces. Applications are limited to traditional solar modules, which cannot meet architectural aesthetic requirements. | Through ultra-thinning processes (wafer thinning/stripping) and stress management design, crystalline silicon wafers can be molded to curved surfaces. Successfully developed the world's first curved crystalline silicon photovoltaic tile. Enabling large-scale production and installation while ensuring structural strength and electrical performance. |
Color Transmission Efficiency | Colored or translucent designs block or reflect some light, significantly reducing power generation efficiency. Uneven color, short lifespan, and prone to fading or aging. It's difficult to balance aesthetics and efficiency. | Utilizing nano-optical films, functional coatings, and digital ceramic printing, these technologies achieve more uniform and stable colors. Optimizing spectral selectivity achieves a balance between light transmission and power generation efficiency. Successfully breaking the "color vs. efficiency" dilemma, achieving both aesthetically pleasing and efficient BIPV products. |
To date, Yingli|Gain Solar has launched 13 generations of BIPV products, including four product series: "Black Brick," "Solar Tile," "Colored Glaze," and "Crystal Clear." These products provide renewable energy solutions for building roofs, facades, sunshades, and surrounding structures. The company has applied for 344 patents, co-edited and co-edited 18 international and national standards, and published China's first SEMI international standard in this field, the "Classification Standard for Building Integrated Photovoltaics (BIPV)." In conjunction with the China Academy of Building Standard Design, the national building standard design atlas, "Integrated Design and Installation of Solar Modules for Buildings," was jointly released with the China Academy of Building Standard Design, filling a gap in the industry.
Yingli|Gain Solar CEO Zhang Yifei stated that the company will continue to increase R&D investment, deepen industry collaboration, and promote the large-scale application of BIPV technology in green buildings, zero-carbon parks, urban renewal, and new urbanization. This will inject new momentum into the development of the green building industry and provide solid product support for achieving the "dual carbon" goals in the construction sector.
