Briefly describe the classification of silicon solar cell modules and the role of module testers

　　Solar cell modules refer to the interconnection and packaging of multiple individual solar cells into modules. It is a minimum indivisible solar cell combination device with external packaging and internal connections, capable of providing separate DC power output. Single solar cells often have low output voltage, inappropriate output current, and crystal silicon cells themselves are relatively brittle, making it difficult to independently withstand harsh external conditions. Therefore, in practical use, it is necessary to connect individual solar cells in series or parallel. And it is packaged and comes into contact with external wires to become a solar cell module that can be used independently as a photovoltaic power source. Also known as photovoltaic modules.

　　Silicon solar cells can be divided into: monocrystalline silicon solar cells, polycrystalline silicon thin film solar cells, and amorphous silicon thin film solar cells.

　　Single crystal silicon solar cell: It is a solar cell made from high-purity single crystal silicon rods, with the highest conversion efficiency and the most mature technology. High performance monocrystalline silicon batteries are based on high-quality monocrystalline silicon materials and related heat treatment processes.

　　1. Amorphous silicon thin film solar cells: The silicon used is a-Si. Its basic structure is not a pn junction but a pin junction. Boron doping forms a p-region, phosphorus doping forms an n-region, and i is a non impurity or lightly doped intrinsic layer.

　　Highlight: Low cost of materials and manufacturing processes; The production process is low-temperature (100-300 ℃), with low energy consumption; Easy to form large-scale production capacity, production can be fully automated throughout the process; There are many varieties and a wide range of uses.

　　2. Existing problems: The optical bandgap is 1.7eV → insensitive to long wave regions → low conversion efficiency; Photoinduced decay effect: The photoelectric efficiency decays with the extension of illumination time; Solution: Preparation of stacked solar cells, which involves depositing one or more p-i-n sub cells onto the prepared p-i-n single junction solar cells; Production methods: reactive sputtering method, PECVD method, LPCVD method; Reaction gas: SiH4 diluted with H2; Substrate materials: glass, stainless steel, etc.

　　3. Polycrystalline silicon thin film solar cells: Polycrystalline silicon thin films are grown on low-cost substrate materials, and a relatively thin crystalline silicon layer is used as the activation layer of the solar cell. This not only maintains the high performance and stability of crystalline silicon solar cells, but also significantly reduces the amount of material used, significantly reducing the cost of the battery. The working principle of polycrystalline silicon thin film solar cells, like other solar cells, is based on the photovoltaic effect formed by the interaction between sunlight and semiconductor materials.

　　4. Common preparation methods: Low pressure chemical vapor deposition (LPCVD); Plasma enhanced chemical vapor deposition (PECV) liquid phase epitaxy (LPPE); Sputtering deposition method; Reaction gases SiH2Cl2, SiHCl3, SiCl4 or SiH4; ↓ (in a certain protective atmosphere)

　　Polycrystalline silicon thin film cells, due to the use of less silicon than monocrystalline silicon, the problem of inefficiency degradation, and the possibility of being prepared on inexpensive substrate materials, have much lower costs than monocrystalline silicon cells and higher efficiency than amorphous silicon thin film cells. Therefore, polycrystalline silicon thin film cells will soon dominate the solar power market.

　　The completion of photovoltaic module production requires electrical performance testing and defect detection, mainly detecting the power, conversion efficiency, internal defects, and appearance defects of the modules. Therefore, it is necessary to use equipment such as module IV tester and EL appearance defect detector for testing. The classification can be based on the power of photovoltaic modules.