大多数大块硅产品鉴定(Production Validation)模块由透明表面、封装、背面和围绕外边缘的框架组成。大部分组件中,顶面是玻璃,封装剂是伊娃(醋酸乙烯乙酯),背面是彼得.这只是一块玻璃太阳能电池板。柔性元件的表面可以是ETFE或宠物，贴片元件的背面是多氯联苯.
PV module Surface material
The front surface of the photovoltaic module must have a high light transmittance within the wavelength range that the solar cell in the photovoltaic module can use. For silicon solar cells, the top surface must have high light transmittance in the wavelength range of 350 nm to 1200 nm. In addition, the reflection of the front surface should be very low. Although theoretically, this reflection can be reduced by applying antireflection coatings on the top surface, in practice, these coatings are not strong enough to withstand the use conditions of most photovoltaic systems. Another technique to reduce reflection is to “roughen” or texture the surface. However, in this case, dust and dirt are more likely to adhere to the top surface and are less likely to be dispersed by wind or rain. Therefore, these components are not “self-cleaning”, and the advantage of reducing reflection is quickly offset by the loss caused by the increase of dirt on the top surface.
In addition to reflection and transmission characteristics, the surface material shall be impermeable, have good impact resistance, be stable under long-term ultraviolet radiation, and have low thermal resistivity. Water or steam entering PV modules will corrode metal contacts and interconnecting devices, thus greatly reducing the service life of PV modules. In most components, the front surface is used to provide mechanical strength and stiffness, so the surface or rear surface must have mechanical stiffness to support the solar cells and wiring.
There are several choices of surface materials, including acrylic, polymer and glass. Tempered glass with low iron content is the most commonly used glass because of its low cost, robustness, stability, high transparency, impermeability to water and gas, and good self-cleaning performance.
PV module Encapsulant
The encapsulant is used to provide adhesion between the top surface and the rear surface of the solar cell sheet and photovoltaic module. The encapsulation agent should be stable under high temperature and high ultraviolet radiation. It should also be optically transparent and have low thermal resistance. EVA (vinyl acetate ethyl ester) is the most commonly used packaging material. EVA is a thin sheet, which is inserted between the solar cell and the top and back. The interlayer is then heated to more than 100 degrees to polymerize EVA and glue the components together.
PV module Rear surface
The main feature of the back surface of the PV module is that it must have low thermal resistance and must prevent water or steam from entering. In most modules, thin polymer plates are used on the back surface. Some photovoltaic modules, called double-sided modules, are designed to receive light from the front or back of the solar cell. In the double-sided assembly, both the front and rear must be optically transparent
PV module frame
The last structural part of the solar panel is the frame or frame of the solar panel. Traditional PV module frames are usually made of aluminum. The frame structure shall be free from projections that may cause the retention of water, dust or other substances.
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