Detailed explanation of solar battery manufacturing process process -Lithium - Ion Battery Equipment
In order to reduce the manufacturing costs of solar batteries, scientists follow two paths: one is the material to develop novel solar batteries, and the other path is to improve the conversion efficiency of solar batteries itself. The endless sunshine is transformed into an electric energy for humans. The core technology is the photoelectric conversion rate of solar cells.
There are more than a dozen semiconductor materials for solar batteries, so there are many types of solar batteries. At present, the most mature technology and the most widely used solar cells are silicon solar batteries.
Silicon solar battery manufacturing process process
1. Cut the silicon wafer, materials preparation:
The single crystal silicon material used in industrial silicon batteries is generally used to use the solar single crystal silicon rod made of a straight pot. The side length is generally 10 ~ 15cm, the thickness is about 200 ~ 350um, and the resistivity of about 1Ω.cm (global energy -saving and environmentally friendly network boron is mixed).
2. Remove the damage layer:
In the cutting process, there will be a large number of surface defects. These two problems will occur. First of all, the quality of the surface is poor. In addition, these surface defects will increase the fragments during the battery manufacturing process. Therefore, the cutting damage layer should be removed. Generally, alkaline or acid corrosion is used, and the thickness of the corrosion is about 10um.
The velvet is to corrode the surface of the relatively smooth raw material silicon wafers through acid or alkali to make it uneven and rough, forming a long reflection, and reducing the loss of solar energy directly to the surface of the silicon wafer. For single crystal silicon, it is generally used to corrode NaOH alcohol. The various heterosexual corrosion of the single crystal silicon is used to form countless pyramid structures on the surface. About 15 minutes. For polycrystalline, acid method is generally used.(Lithium - Ion Battery Equipment)
4. diffusion knot:
The purpose of diffusion is to form a PN knot. Phosphorus is generally used for N -type doping. Due to the high temperature of solid -state diffusion, it is very important to clean the surface of the silicon wafer surface before the diffusion. It is required to clean the silicon wafer after the velvet is made, that is, the alkali residue and metal impurities on the surface of the silicon wafer surface with acid and silicon wafer surface.
5. Edge etching and cleaning:
During the diffusion process, a diffusion layer is also formed on the surrounding surface of the silicon wafer. The peripheral diffusion layer makes the upper and lower electrode of the battery form a short -circuit ring, which must be removed. Any tiny local short -circuit on the surroundings will reduce the battery parallel resistance and even become waste. At present, industrialized production is corroded by a plasma dry method. Under the condition of gifted discharge conditions, the use of fluorine and oxygen is used to remove the surroundings containing the diffusion layer.
The purpose of cleaning after diffusion is to remove silicone glass formed during the diffusion process.
6. Deposition reduction reflex layer:
The purpose of sedimentary reduction reflective layer is to reduce surface reflection and add refractive index. PECVD is widely used to deploy SIN. Since PECVD deploys SIN, not only grows SIN as a reduction of anticipulum, but also generates a large amount of atomic hydrogen. Production in large quantities.
7, screen printing up and down electrodes:
The preparation of the electrode is a vital step in the preparation of the solar cell. It not only determines the structure of the launch area, but also determines the area of the series resistance of the battery and the area covered by the metal surface. The earliest vacuum steaming or chemical electroplating technology is used, and now the wire printing method is generally used, that is, the silver paste (silver aluminum pulp) is printed on the positive back of the solar cell through a special printing machine and template to form positive and negative electrodes. lead.
8. Burns to form metal contact:
The crystal silicon solar battery must be printed through three times of metal slurry. Traditional techniques must be used with secondary sinters to form a good metal electrode Ohm contact. A total of only one -time sintering process is required. In the production of solar battery screen printing electrodes, a chain sintering oven is usually used for rapid sintering.
9. Battery test:
The completed battery films are classified by testing.