According to statistics from the European Photovoltaic Industry Association (EPLA) in 2012, crystalline silicon solar cells have always accounted for the vast majority of the solar cell market and are the mainstream of photovoltaic power generation. The market distribution of different types of solar cells is shown in Figure 1.
Since the crystalline silicon solar cell itself is easily broken and easily corroded, if it is directly exposed to the atmosphere, the photoelectric conversion efficiency will decrease due to the influence of humidity, dust, acid rain and other factors, and it is also easy to be damaged. Therefore, crystalline silicon solar cells generally must be used after being made into a flat structure by means of glue sealing, lamination, etc., as a power source, several single cells must be connected in series and parallel and tightly sealed. This is a solar cell module. The physical appearance of the solar cell module is shown in Figure 2.
Solar cell module packaging is a key link in the long-life utilization of solar cells to isolate the communication channels between the solar cells and the outside atmosphere, protect the electrodes and avoid corrosion of interconnections. In addition, the use of rigid materials for encapsulation also avoids solar cell fragmentation. The quality of the encapsulation determines the performance and service life of the crystalline silicon solar cell module. The encapsulation of crystalline silicon solar cells mainly adopts the vacuum hot pressing method. After the solar battery cells welded by the positive and negative electrodes are connected in series and parallel to form a crystalline silicon solar battery array, EVA (Ethylene/Vinyl Acetate) material is used on both sides, and then add low-iron tempered glass and TPT on both sides, put them into the vacuum laminator, vacuum and heat the laminating chamber, and heat press the glass/EVA battery string/EVA/TPT together to ensure the practicability, interchangeability, reliability and longevity of use. Among them, TPT (Tedler-Polyeast Tedler) is the covering on the back of the solar cell and is a white fluoroplastic film. After the components are packaged, they have sufficient mechanical strength to withstand the conflicts, vibrations and other stresses that occur during transportation, installation and use, and reduce the overall power loss.
Solar cell module structure
The conventional solar cell module structure has the following types: glass shell structure module, flat structure module, and full glue sealing module without cover.
Among them, the glass shell structure is shown in Figure 3, the flat panel assembly is shown in Figure 4, and the all-glue sealing assembly without a cover is shown in Figure 5.
