The global photovoltaic cell market is dominated by crystalline silicon cells. Improving efficiency and reducing cost of crystalline silicon battery is the key to the development of photovoltaic industry. From the initial mass-produced aluminum back-field cells, to PERC (emitter passivation and back contact) , to HJT (heterojunction of the intrinsic amorphous layer) cells and TOPCon (tunnel oxide passivation contact cells) , and to future laminated cells, the efficiency of photovoltaic cells is approaching the limit, which leads to a breakthrough in cost and scale.
Although the technology of photovoltaic cells has been iterated and the efficiency has been improved, the basic principle and core process of crystalline silicon cells have not changed, that is, cleaning cashmere, diffusion knot, passivation coating, metallization four steps.
1) cleaning flocking cleaning is mainly used to remove impurities and damage layer on the surface of silicon wafer, flocking is used to form a pyramid structure on the surface of silicon wafer to reduce reflectivity.
2) P-N junction is the core structure of photovoltaic cells. It is usually suitable for homogeneous junction batteries.
3) the passivation film is formed on the surface of the cell by vacuum plating, which plays a key role in improving the efficiency of the cell and is the main starting point of improving the efficiency of the cell.
4) Metallization is used to form the front and back electrodes of a photovoltaic cell, usually by screen printing. The metallization process is closely related to the passivation process, and plays a key role in reducing minority recombination and resistance loss. In addition, also includes etching, detection and other general steps, in the different battery technology line of little difference.