Eight core materials for solar modules

 Photovoltaic modules refer to the smallest and indivisible combination of photovoltaic cells with packaging and internal connections that can provide direct current separately. It is the core component of a photovoltaic power generation system, composed of eight core materials. Today, let's learn about the eight important materials that make up components!

Solar Cells 

 The solar cell is the most core component of the module, mainly used to convert light energy into electrical energy. After the solar cells are connected in series or 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 with the controller, battery pack, inverter and other components to form a photovoltaic power generation system.

 Solar cells are divided into monocrystalline silicon, polycrystalline silicon, and amorphous silicon solar cells based on their raw materials. Crystal silicon cells technology is based on silicon wafers as a substrate, and generates electricity through the separation of photo generated carriers using PN junctions. According to the differences in raw materials and cells preparation technology, crystalline silicon cells are divided into P-type cells and N-type cells. P-type silicon wafers are made by doping boron elements in silicon materials. The preparation techniques for P-type cells include traditional AL-BSF (aluminum back field) and PERC technologies; N-type silicon wafers are made by doping phosphorus elements in silicon materials, and there are many preparation technologies for N-type cells, including PERC, TOPCon, IBC, and HJT.

 Among them, heterojunction cells is one of N-type cells, which has many advantages such as high conversion efficiency, high power generation, low temperature coefficient, no photoinduced attenuation and potential attenuation, simple preparation process, high double-sided power generation efficiency, etc. With the continuous breakthroughs in cells technology and the continuous acceleration of industry processes, heterojunction technology is expected to become the next generation of mainstream battery technology.

Glass

 Photovoltaic glass is a type of sodium calcium silicate hydrochloric acid glass mainly used for packaging photovoltaic modules. Photovoltaic glass will directly affect the power generation efficiency and service life of photovoltaic modules.

 Photovoltaic glass is generally low iron tempered glass or semi tempered glass, which has the following characteristics. One is good permeability. The transmittance is a key factor affecting the conversion efficiency of photovoltaic cells. Photovoltaic glass needs to have high transparency and high reflectivity for 1200nm infrared light. Secondly, it has high mechanical strength. Impact resistant, able to withstand 2400Pa wind pressure and 5400Pa snow pressure, providing support and protection. Thirdly, it has good durability. Due to the influence of climate and geographical location, components need to be operated in an open air environment with a large temperature difference between day and night, and must possess corrosion resistance and weather resistance characteristics.

 Heterojunction battery components are generally packaged with ultra-white low iron tempered glass, which has high light transmittance and less impurities, making them less prone to self explosion. The front of the heterojunction battery module is made of tempered coated glass, which can enhance the light transmittance.

Film

 Photovoltaic packaging film is an important component of photovoltaic modules, located on the upper and lower sides of the battery cell. The primary function of the adhesive film is to bond the battery to the glass and back panel. Secondly, the adhesive film can play a protective role in packaging, protecting the battery circuit from external environmental interference, and extending the service life of the components. In addition, the packaging adhesive film can enhance the light transmittance of the photovoltaic module, thereby improving the power generation efficiency of the module. Finally, the adhesive film can also serve as a structural support and positioning battery during the production, storage, installation, and use of components.

 According to the materials, the mainstream adhesive films mainly include EVA, POE, EPE, and PVB. EVA film is a mainstream photovoltaic packaging film with good transparency, processing performance, stable supply, and low cost. However, it has disadvantages such as high water vapor permeability, low impact resistance, and unstable PID resistance. POE adhesive film has low water vapor transmittance and good PID resistance, making it suitable for packaging double glass components and N-type components. However, its processing properties are poor and its cost is high.

 Heterojunction double glass components are packaged with POE adhesive film, which has high water resistance and PID resistance, providing reliable guarantee for efficient heterojunction components.

Backboard

 Photovoltaic backboard are packaging materials used for back protection, typically used for single glass modules. Photovoltaic backboards are divided into fluorinated backboards and non fluorinated backboards. Fluorinated backboards include TPT, TPE, TPC, CPC, and non fluorinated backboards include PET, PA/PO, etc.

 Photovoltaic backboard are mainly used to resist the erosion of materials such as battery cells and adhesive films in humid and hot environments, providing corrosion resistance, weather resistance, oxidation resistance, and insulation protection, effectively extending the service life of components. The white backboard has high reflectivity, which can improve the conversion efficiency of the component. At the same time, the high infrared reflectivity also facilitates the reduction of the operating temperature of the components.

Solder strip

 Photovoltaic solder strip is a composite conductive material formed by coating tin based solder on the surface of copper strip. It is used in series or parallel connection of photovoltaic cells to collect current and conduct electricity. It is an important material in the welding process of photovoltaic modules.

 Photovoltaic welding strips are divided into interconnection welding strips and busbar welding strips. Interconnecting solder strips are used to connect photovoltaic cells and collect and transmit current from the cells. The busbar welding strip is used to collect the current generated by the battery string and lead it out to the junction box. The welding strip has a direct impact on the current collection, thus affecting the power and power generation efficiency of the module.

 In the early days of the industry, flat welded strips were used. With the development of the industry, currently efficient components are all made of round welded strips. The Aikang HJT module adopts low-temperature round wire welding strip, with the core made of oxygen free copper and the outer layer coated with tin lead alloy, combined with low-temperature soldering flux, for welding at 165-190 ℃.

Silicone

 Silicone is mainly used for bonding and sealing laminated glass photovoltaic modules, bonding frames to glass, junction boxes to backboards (or glass), and playing a sealing and connecting role.

 According to the different usage positions, silicone is divided into sealant and potting adhesive. Sealant is used in the frame card slot and at the bottom of the junction box and backplane. Sealing glue is generally used inside the junction box to protect the internal circuits.

junction box 

 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. It can seal, waterproof, and dustproof the outgoing lines of photovoltaic modules. The junction box also plays a role in protecting the safe operation of the photovoltaic module system. If a module experiences a short circuit, the junction box will automatically disconnect the short circuit battery string to prevent the entire system from being burned out.

 Aikang high-efficiency components mainly use split junction boxes, which need to be fixed on the photovoltaic module during use. Pour sealing glue into the junction box and apply sealant on the edges to provide sealing and fixation.