A solar cell module refers to the smallest indivisible assembly of solar cells that is encapsulated and internally connected, and capable of providing direct current output independently. There are many types of solar cell modules.
Based on the type of solar cell, solar cell modules can be divided into crystalline silicon (monocrystalline and polycrystalline silicon) solar cell modules, amorphous silicon thin-film solar cell modules, and gallium arsenide solar cell modules, etc.; based on the different encapsulation materials and processes, they can be divided into epoxy resin encapsulated solar panels and laminated encapsulated solar cell modules; based on the different applications, they can be divided into general-purpose solar cell modules and building material solar cell modules.
Polycrystalline silicon solar cell modules are a new generation of solar cell modules that combine the high conversion efficiency and long lifespan of monocrystalline silicon cells with the relatively simplified material fabrication process of amorphous silicon thin-film cells. A polycrystalline silicon solar cell module is a component of a polycrystalline silicon solar cell. Below, we will learn about the main components and functions of a polycrystalline silicon solar cell module.
1. Tempered glass: Its function is to protect the main body of the power generation battery cells. Its selection is subject to requirements: (1) The light transmittance must be high, generally above 91%); (2) Ultra-white tempered treatment.
2. EVA: Used to bond and fix tempered glass and the main solar cells. The quality of transparent EVA material directly affects the lifespan of the module. EVA exposed to air is prone to aging and yellowing, which affects the light transmittance of the module and thus the power generation quality. In addition to the quality of the EVA itself, the lamination process of the module manufacturer also has a great impact. For example, if the EVA adhesiveness is not up to standard, or if the bonding strength between EVA and tempered glass and backsheet is insufficient, it will cause the EVA to age prematurely and affect the lifespan of the module.
3. Solar Cells: Their main function is to generate electricity. The mainstream solar cells on the market are crystalline silicon solar cells and thin-film solar cells. Each has its advantages and disadvantages. Crystalline silicon solar cells have relatively low equipment costs, but high consumption and cell costs. However, they also have high photoelectric conversion efficiency and are more suitable for generating electricity under outdoor sunlight. Thin-film solar cells have relatively high equipment costs, but very low consumption and cell costs. However, their photoelectric conversion efficiency is only slightly more than half that of crystalline silicon solar cells. They have excellent low-light performance and can generate electricity even under ordinary light, such as the solar cells on calculators.
4. EVA: Its function is as described above, mainly to bond and encapsulate the power generation unit and backsheet.
5. Backsheet: Its function is to seal, insulate, and waterproof. It is generally made of materials such as TPT and TPE and must be resistant to aging. Module manufacturers offer a 25-year warranty. Tempered glass and aluminum alloy are generally fine. The key is whether the backsheet and silicone can meet the requirements.
6. Aluminum alloy: Protective laminate, providing a certain degree of sealing and support.
7. Junction Box: Protects the entire power generation system and acts as a current transfer station. If the module is short-circuited, the junction box will automatically disconnect the short-circuited battery string to prevent the entire system from burning out. The most critical part of the junction box is the selection of diodes. The corresponding diodes are different depending on the type of battery cells in the module.
8. Silicone: Used for sealing, sealing the junction between components and aluminum alloy frames, and between components and junction boxes. Some companies use double-sided tape or foam to replace silicone, but silicone is widely used in China because it is simple, convenient, easy to operate, and has a low cost.
