1 How many parts are photovoltaic modules composed of?
Solar power generation, also known as photovoltaic modules, is the core component of photovoltaic power plants. Today, we will provide a detailed analysis of its main components:
It is mainly composed of solar cells, glass cover, EVA encapsulation, backsheet, aluminum frame, junction box, solder tape, and silicone.
1. Photovoltaic cells
The core component of photovoltaic modules is responsible for converting light energy into electrical energy. After the battery cells are connected in series and parallel to reach a certain rated output power and voltage, they form photovoltaic modules. Photovoltaic modules are combined to form a photovoltaic array, which is connected to components such as controllers, battery packs, inverters, etc. to form a photovoltaic power generation system.
Battery cells are usually made of silicon materials, including monocrystalline silicon, polycrystalline silicon, and thin-film cells.
Crystalline silicon cell technology is based on silicon wafers as substrates, and generates electricity by separating photo generated carriers based on PN junctions. According to the differences in raw materials and battery preparation technology, crystalline silicon batteries are divided into P-type batteries and N-type batteries.
2. Glass Cover
Photovoltaic glass is a type of sodium calcium silicate hydrochloric acid glass located at the forefront of the module, protecting the solar cells from external environmental factors such as wind, rain, snow, etc. Generally, high transmittance tempered glass is used to increase light absorption efficiency. Therefore, photovoltaic glass needs to have high transparency and high reflectivity for 1200nm infrared light. Secondly, it has high mechanical strength. Impact resistant, capable of withstanding wind pressure of 2400Pa and snow pressure of 5400Pa, providing support and protection. Thirdly, it has good durability. Due to the influence of climate and geographical location, components need to operate in outdoor environments with large temperature differences between day and night, and must have corrosion resistance and weather resistance characteristics.
3. EVA film (EVA encapsulation)
Used for packaging battery cells, ensuring that the cells are fixed between the glass cover plate and the back plate. EVA film has good adhesion and light transmittance, while providing some cushioning protection.
According to the materials, the mainstream adhesive films mainly include EVA POE,EPE,PVB. EVA film is the mainstream photovoltaic packaging film, with good transparency, good processing performance, stable supply, and low cost. However, it has disadvantages such as high water vapor penetration, low impact resistance, and unstable PID resistance. POE film has low water vapor permeability and good resistance to PID, making it suitable for packaging double glass components and N-type components. However, it has poor processing properties and high costs.
4. Backsheet
Located on the back of the component, it protects the battery cells and internal structure from mechanical damage and environmental erosion. Usually made of highly weather resistant materials, it has good electrical insulation and moisture resistance.
Photovoltaic backboards are divided into fluorinated backboards and non fluorinated backboards. Fluorinated backboards have TPT TPE,TPC,CPC, Non fluorinated backboards include PET, PA/PO, etc.
5. Aluminum Frame
Used to support and protect the structure of photovoltaic modules, provide mechanical strength of the modules, support the connection carrier between the modules and brackets, and use frames to improve the overall mechanical strength and load-bearing capacity of the modules, thereby extending their lifespan.
6. Junction Box
Located on the back of the module, connect the photovoltaic module to the external circuit through a cable. The junction box usually contains diodes to prevent reverse current flow and protect the battery cells from damage. The junction box mainly consists of a junction box cover, sealing ring, diode, heat dissipation device, box body, wires, and connectors. The main function of a junction box is to connect the electricity generated by solar cells to external circuits.
7. Photovoltaic ribbon, silicone
Photovoltaic ribbon is a composite conductive material formed by coating tin based solder on the surface of copper ribbon, which is used for series or parallel connection of photovoltaic cells to collect current and conduct electricity.
Silicone is mainly used for bonding and sealing laminated glass photovoltaic modules, bonding frames and glass, junction boxes and backplates (or glass), playing a sealing and connecting role. According to different usage locations, silicone is divided into sealant and potting adhesive.
2 Process flow of photovoltaic modules
According to the important components of photovoltaic modules mentioned above, the specific manufacturing process of photovoltaic modules can be divided into welding, stacking, laminating, EL testing, framing, junction box assembly, cleaning, IV testing, finished product inspection, packaging, etc.