Solar panel introduction
Solar cells, also known as "solar chips" or "photocells," are photovoltaic semiconductor wafers that use solar light to generate electricity directly. Single-cell solar cells cannot be used directly as power supplies. As a power source, several individual solar cells must be connected in series, connected in parallel, and tightly sealed into components.
Solar panels (also called solar modules) A plurality of solar cells are assembled in the solar power system and are the most important part of the solar power system.
Solar panel structure and various functions
(1) Tempered glass: Its function is to protect the main body of power generation (such as battery sheets). The choice of light transmission is required:
1. The light transmittance must be high (generally 91% or more); 2. Ultra-white steel treatment.
(2) EVA: used to bond fixed tempered glass and power generation main body (cell sheet). The quality of transparent EVA material directly affects the life of components. EVA exposed to air is prone to aging and yellowing, thus affecting the light transmission of components. Rate, which affects the power generation quality of the components. In addition to the quality of the EVA itself, the influence of the lamination process of the component manufacturers is also very large. For example, if the EVA adhesiveness is not up to standard, the bonding strength of EVA and tempered glass and backing plate is insufficient, and EVA will be caused. Early aging affects component life.
(3) Cell: The main function is power generation. The mainstream of the main power generation market is crystalline silicon solar cells and thin film solar cells, both of which have advantages and disadvantages. Crystalline silicon solar cells, the equipment cost is relatively low, but the cost of consumption and cell is high, but the photoelectric conversion efficiency is also high, and it is more suitable to generate electricity in outdoor sunlight.
Thin film solar cells, relatively high equipment cost, but the consumption and battery cost are very low, but the photoelectric conversion efficiency is more than half of the crystalline silicon cell, but the weak light effect is very good, and it can generate electricity under ordinary light, such as calculator. Solar cells on.
(4) Backboard: function, sealed, insulated and waterproof. Generally, materials such as TPT and TPE must be resistant to aging. Most component manufacturers are guaranteed for 25 years. Tempered glass and aluminum alloys are generally no problem. The key is whether the backsheet and silica gel can meet the requirements.
(5) Aluminium alloy: protects the laminate and plays a certain role in sealing and supporting.
(6) Junction box: protects the entire power generation system and acts as a current transfer station. If the component short-circuits the junction box to automatically disconnect the short-circuit battery string, the most critical factor in preventing the burnout of the entire system junction box is the selection of the diode, according to the components. The type of the battery is different, and the corresponding diodes are different.
Silicone: Sealing effect, used to seal components and aluminum alloy frame, assembly and junction box. Some companies use double-sided tape and foam instead of silica gel. Silicone is widely used in China. The process is simple, convenient and easy to operate. And the cost is very low.
Solar panel production method (1)
The first step: first, the titanium dioxide powder is placed in a mortar and ground with a binder, and then slowly coated on a conductive glass with a glass rod to prepare a titanium dioxide film. The titanium dioxide film is placed under an alcohol lamp to be cured and cured. Minute, cool
The second step: Coloring the titanium dioxide with natural dyes As shown in the figure, fresh or frozen black plum, sorbet, pomegranate seeds or black tea is squeezed out with a large spoon, and then the titanium dioxide film is placed for coloring. It takes about 5 minutes until the film turns dark purple. If the film is unevenly colored on both sides, it can be soaked for 5 minutes, then rinsed with ethanol and lightly dried.
The third step: making the positive and negative electrodes of the battery. It consists of a layer of SnO2 coated with electricity, and a layer of graphite is uniformly coated on the conductive surface with a 6B pencil.
The fourth step: adding the electrolyte using the solution containing iodide ions as the electrolyte of the solar cell. As shown in the figure, one or two drops of electrolyte may be added dropwise to the surface of the titanium dioxide film.
The fifth step: Assembling the battery Place the colored titanium dioxide film face up on the table, drop one or two drops of electrolyte containing iodine and iodide ions on the film, and then press the conductive surface of the negative electrode down on the titanium dioxide film. . The two sheets of glass were slightly staggered so that the exposed portion was used as a test for the electrodes. Use two clips to clamp the battery so that your solar cell is made.
The sixth step: Testing the battery Under outdoor sunlight, a solar cell with an open circuit voltage of 0.4V and a short-circuit current of 1mA/cm2 can be obtained.
Solar panel production method (2)
1. The first step is to first connect the cells in series with a copper strip. A piece of battery is equivalent to a small power generation unit that can generate 0.5V, 5.2A current, and use a copper strip to connect a certain number of cells in series to obtain more power.
2. Then you need to seal the battery, isolated from the air, otherwise it will gradually decay until the power generation is zero. Therefore, the second step is to use tempered glass, EVA, and backing plate. After heating and vacuuming, the battery piece can be sealed between the glass and the back plate.
3. But the strength of tempered glass is not enough, it is easy to be damaged, especially in the corners. Therefore, the third step is to put an aluminum frame around it to protect it. After the above three steps, the solar panels are produced.
Solar panel production method (3)
1. Battery test: First classify the performance parameters of the battery, so that it effectively combines the batteries together. The battery test is classified by testing the parameter size of the battery, etc., making a quality qualified battery and improving the efficiency of the battery.
2, front welding: the bus bar is welded to the front of the battery (negative electrode) on the main grid line, the bus bar is tinned copper strip, we use the welding machine can weld the strip in the form of multiple points on the main grid on-line.
3, back series: It is based on different solar panels using different templates, so that the size of the back soldering groove corresponds to the size of the battery, fully integrated.
4. Laminated laying: When the back side is connected in series and passed the inspection, the component string, glass and cut EVA, glass fiber and backing board are laid according to a certain level, ready for lamination.
5. Component lamination: The laid battery is placed in a laminating machine, the air in the assembly is drawn out by vacuuming, and then heated to fuse the EVA to bond the battery, the glass and the back sheet together; finally, the assembly is cooled and taken out.
6. Trimming: When the EVA is melted after lamination, it will form a burr by externally extending and solidifying due to the pressure. At this time, the staff will perform the cutting.
7. Binding: similar to attaching a frame to the glass; attaching the aluminum frame to the glass component, increasing the strength of the component, further sealing the battery component, and prolonging the service life of the solar panel.
8. Solder junction box: Weld a box at the back of the assembly to facilitate connection to other equipment.
9. High-voltage test: High-voltage test refers to applying a certain voltage between the component frame and the electrode lead, testing the component's pressure resistance and dielectric strength, and testing whether it can be used normally under severe conditions.
10, component testing: This is the final test, mainly to determine the output power of the battery, test its output characteristics, so that the quality level of the solar panel can be displayed.