Application of Air Compressor in Photovoltaic Cell Production

In the production of photovoltaic cells, the air compressor is the core equipment to ensure process accuracy and product quality, and its application runs through the whole process of silicon wafer processing, cell chip manufacturing and component packaging. The following analysis of its specific role and technical requirements from a professional point of view:

application of 1. Core Process

1. wafer Cleaning and Cashmere Making
   • function: Provide high-pressure airflow to purge the surface of the silicon wafer to remove metal impurities, organic pollutants and cutting damage layers.
   • Technical requirements: Precision filters are required to ensure that the gas cleanliness reaches ISO 8573-1 Class 1 standard to avoid particle pollution leading to a decrease in battery efficiency.
   • Process value: The pyramid-shaped suede structure is formed by the velvet process, which can reduce the light reflectivity from 30% to less than 10%, and significantly improve the short-circuit current of the battery.
2. diffusion bonding
   • function: During the formation of the PN junction, the doping gas (such as POCl) is accurately delivered through the mass flow controller, and the stable gas flow field in the furnace tube is maintained.
   • Technical requirements: need to be equipped with frequency conversion speed regulation system, to ensure that the gas flow fluctuation <± 1%, to ensure the uniformity of PN junction.
   • Process value: directly affects the open circuit voltage of the battery, and the high-quality PN junction can increase the conversion efficiency by 0.3-0.5.
3. plasma etching
   • function: Provide the carrier gas of the reaction gas (such as CF?), and maintain the pressure of the vacuum chamber stable.
   • Technical requirements: oil-free scroll air compressor shall be used to avoid the increase of etching edge roughness caused by oil vapor pollution.
   • Process value: Precisely remove the PN junction at the edge of the silicon wafer, reduce the edge leakage current to less than 0.1μA, and improve the anti-PID performance of the component.
4. Coating and screen printing
   • function: Provide the carrier gas of process gas (such as SiH?/NH3) during PECVD coating, and purge the excess slurry after screen printing.
   • Technical requirements: a cold dryer shall be configured to control the pressure dew point at -40 ℃ to prevent water vapor from causing the film to fall off.
   • Process value: silicon nitride antireflection film can increase light absorption rate by 4%-6%, and high-quality electrode printing can reduce series resistance to below 0.5 mΩ · cm².

2. special process requirements

1. oil-free standard
   • it is necessary to use a model that has passed TÜV Class 0 oil-free certification, and the oil content of the gas is less than 0.01 mg/m & sup3; To avoid oil pollution causing black spots in the EL test of the battery.
2. Pressure stability
   • key processes (such as diffusion and coating) shall be equipped with gas storage tank and pressure maintenance valve to ensure that the air pressure fluctuation is <± 0.02MPa and the process repeatability is guaranteed.
3. Energy Efficiency Management
   • it is recommended to use the permanent magnet frequency conversion model, which saves 25%-35% energy compared with the power frequency machine. With the heat recovery system, the compression heat can be used to preheat the water washing tank, thus improving the comprehensive energy efficiency by 40%.

3. typical application cases
take 210mm large size silicon wafer production as an example:

• device Configuration: 4 GW37 non-oil-water lubricated air compressors (rated pressure 0.8MPa, displacement 6.1m & sup3;/min)
• process matching:
  • cleaning and velvet making: double-machine linkage air supply, flow fluctuation <± 3%
  • diffusion junction: equipped with precision pressure regulating valve, pressure stability of 0.005MPa
  • component lamination: through the combination of cold dryer and adsorption dryer, the pressure dew point is -60 ℃, to ensure that the EVA film is free of bubbles
• energy efficiency performance: system specific power ≤ 5.2kW/(m & sup3;/min), 18% energy saving compared with the industry average

4. selection recommendations

1. capacity matching: According to the single-line capacity calculation, each GW battery production needs to be equipped with 120-150m & sup3;/min air compressor unit.
2. Redundant design: N +1 backup mode is adopted to ensure that the system pressure drop is less than 10% when a single unit fails.
3. Intelligent control: Configure the Internet of Things module to realize real-time monitoring of 20 parameters such as pressure, temperature, energy consumption, etc., and the fault warning response time is less than 3 seconds.

Air compressors have evolved from traditional power sources to precision process equipment in the production of photovoltaic cells, and their technological development is deeply integrated with the trend of large-scale and thin-slice cells. The selection of models with oil-free certification, precision pressure control and intelligent energy-saving functions is an important basis for ensuring the competitiveness of photovoltaic products.