Sunrise Energy Co., Ltd.
Sunrise Energy Co., Ltd.

Main Raw Materials and Components of Solar Cell Modules

Ⅰ. The main raw materials of solar cell modules


1. Photovoltaic glass for solar cell materials


The panel glass used in the battery module is low-iron ultra-white suede tempered glass. The general thickness is 3.2mm and 4mm. Building material solar cell modules sometimes use tempered glass with a thickness of 5~10mm, but the light transmittance is required to be above 90% regardless of the thickness. Tempering is to increase the strength of the glass, resist the impact of wind, sand and hail, and protect the solar cells for a long time. After tempering the panel glass, the strength of the glass can be 3 to 4 times higher than that of ordinary glass.


2. EVA film for solar cell materials


The copolymer of ethylene and vinyl acetate is a thermosetting film-like hot-melt adhesive, which is currently a commonly used bonding solar cell material in the packaging of solar cell modules. Two layers of EVA film should be added to the solar cell module. The two layers of EVA film are sandwiched between the panel glass, the cell and the TPT back sheet film, and the glass, the cell and the TPT are bonded together. After it is bonded with glass, it can improve the light transmittance of glass, play the role of antireflection, and have a gain effect on the power output of solar cell modules.


3. Backsheet materials for solar cell materials


The back sheet material of the solar cell module can be selected in a variety of ways according to the requirements of the solar cell module. Generally, there are tempered glass, plexiglass, aluminum alloy, TPT composite film and so on.


Tempered glass backplane is mainly used to make double-sided light-transmitting building materials type solar cell modules, which are used in photovoltaic curtain walls, photovoltaic roofs, etc. In addition, the most widely used is the TPT composite membrane. TPT composite film has the characteristics of airtightness, good strength, good weather resistance, long service life, no change under lamination temperature, and strong bonding with bonding materials. These features are suitable for encapsulating solar cell modules, and the back sheet solar cell material effectively prevents the erosion and influence of various media, especially water, oxygen, and corrosive gases, on EVA and solar cells.


Ⅱ. Components of solar cell modules


1. Junction box and bypass diode


The dedicated junction box for solar cell modules is a component that connects the internal output line of the battery module with the external line. The positive and negative bus bars drawn from the solar panel enter the junction box, and are plugged or soldered to the corresponding position in the junction box. The leads are also connected to the junction box by means of plugging, soldering, and screw crimping.


When more solar cell modules are connected in series to form a cell array or a branch of the cell array, a diode needs to be connected in reverse parallel to the positive and negative output terminals of each solar panel. The diode connected in parallel at both ends of the module is called a side circuit diode. When a component or a part of the component in the square array string is shaded or fails to stop power generation, a forward bias will be formed at both ends of the bypass diode of the component to make the diode conduct, and the operating current of the component string bypasses the fault. The component, which is bypassed by the diode, does not affect the power generation of other normal components, and also protects the bypassed components from being damaged by high forward bias or heating due to the "hot spot effect".


2. Battery


Crystalline silicon solar cells are divided into monocrystalline silicon cells and polycrystalline silicon cells. The surface of the cell has a blue anti-reflection film and silver-white electrode grid lines. Generally, the electrode wire on the front is the negative wire of the battery, and the electrode wire on the back is the positive wire of the battery. The area of the cell is proportional to the output current and power generation. The larger the area, the greater the output current and power generation.