PERC Double Glass Cell is an important technological breakthrough in the current photovoltaic field. It combines the efficient power generation capacity of PERC cells and the durability of double-glass modules, and is widely used in various complex environments. The technical structure of PERC double-glass cells mainly includes the PERC cell core structure and the double-glass packaging structure. The two complement each other and greatly improve the photoelectric conversion efficiency, mechanical strength and environmental resistance of the cell.
1. PERC cell core structure
PERC technology is an improvement on traditional crystalline silicon solar cells, focusing on the optimized design of the back of the cell. The core technical structure of PERC cells mainly consists of the following parts.
Emitter passivation layer: PERC cells have a passivation layer added to the back, usually composed of aluminum oxide or silicon nitride materials. The main function of this passivation layer is to reduce the recombination of the cell surface and improve the transmission efficiency of carriers. This layer of passivation material can reflect part of the sunlight that passes through the cell and reuse these photons to increase the amount of light absorption. At the same time, the passivation layer can also effectively reduce the recombination loss of surface electrons and increase the open circuit voltage of the cell.
Back surface field (BSF): The back surface field is another key structure of PERC cells. By forming an electron barrier on the back of the cell, BSF can prevent minority carriers from escaping from the cell, thereby reducing the recombination loss of carriers. This design greatly improves the photoelectric conversion efficiency of the cell, especially under long-wavelength infrared light, the performance of PERC cells is even better.
Front anti-reflection layer: In order to further enhance the light absorption efficiency, the front of the PERC cell is usually coated with an anti-reflection coating, usually made of silicon nitride material. This coating can reduce the reflection of sunlight on the surface of the cell and increase the amount of light entering the silicon wafer, thereby improving the photoelectric conversion efficiency of the cell.
Double-glass packaging structure: In addition to the core technology of PERC cells, another key feature of PERC double-glass cells is the use of double-glass packaging structure. This packaging design not only improves the stability and service life of the cell module, but also can better adapt to complex environmental conditions.
2. The double-glass structure of PERC double-glass cells refers to the use of tempered glass on both sides of the cell for packaging. Compared with traditional single-glass modules, double-glass modules are more durable, can withstand greater mechanical stress, and are not easily affected by the external environment. This design effectively reduces the damage to the battery caused by external factors such as thermal expansion and contraction, wind and sand erosion, and moisture penetration, thereby extending the service life of the battery.
EVA film layer: In the double-glass structure, the silicon wafer of the PERC battery is sandwiched between two pieces of tempered glass and encapsulated by EVA (ethylene-vinyl acetate copolymer) film. EVA film can protect the battery silicon wafer and prevent the intrusion of external moisture and impurities. At the same time, it has good optical transparency to ensure that light energy can be efficiently transmitted. In addition, the flexibility of EVA film can absorb the impact force of the module during transportation and installation, and avoid damage to the battery silicon wafer.
Frame design: The frames of PERC double-glass batteries are usually made of aluminum alloy or other corrosion-resistant materials. These frames not only provide mechanical support for the battery components, but also prevent moisture and other contaminants from penetrating into the components from the sides, further improving the sealing and service life of the components. In the double-glass components with frameless design, the selection of sealing materials is also very critical. High-strength silicone or polymer is usually used for encapsulation to ensure the overall sealing and protective performance of the battery.
