Solar photovoltaic systems (monocrystalline silicon photovoltaic systems), our main line of products, are manufactured through the processes in the following illustrations:
The materials of solar cells are high purity virgin polysilicon, and sometimes silicon scraps from the manufacturing processes of ingots and wafers are also reused.
Silicon raw materials are mixed at a certain compound ratio and melted in a crucible at high temperatures (approx. 1420℃ or higher), and a seed crystal is dipped into the molten silicon and slowly pulled out while being rotated to make monocrystalline ingots.
Monocrystalline ingots are manufactured at the following factory:
In this process, cylindrical ingots are cut to form quadrangles that have the size of a wafer from edge to edge. These are completed by grinding.
With this process, wafers are shaped into the rounded-off square that is easy to arrange on a solar panel.
Ingots are manufactured at the following place:
This is a process where ingots are sliced into wafers by machines called "wire saws."
As shown in the illustration, wire saws have two rollers with several thousand grooves that have steel wires wound around them. Ingots are sliced as they are slowly pressed on the wires running at very high speed with cutting fluid. Only the parts in contact with the wire are cut. As a result several thousand wafers are sliced simultaneously.
Ingots are sliced at the following place:
The wafers are cleaned and only those that pass vigorous inspections (all the wafers are tested) become finished products.
Wafers are checked, wrapped and packaged before they are finally shipped to customers.
Monocrystalline silicon wafers are inspected at the following place:
6. Solar cells
Silicon wafers are doped with impurities (such as phosphorus and boron) to create a photoelectric effect, and electrodes are then screen-printed as an "outlet" for electricity.
In addition, the devices use a textured structure (roughness with microscopic pyramid-shape irregularities on the crystalline surface) to efficiently trap sunlight in the power-generation layer and antireflection coatings to utilize sunlight maximally.
7. Solar modules
Electrodes are connected by soldering cells with ribbon wire. Tempered glasses are then used to laminate the assembly of connected cells. Finally, framed with aluminum and equipped with positive and negative terminal boxes, a module is completed.
8. Solar photovoltaic systems
For instance, as shown in the illustration, system-controlled multiple modules are installed over the rooftop of a house, and generate electric power with sunlight.
