Different solar panels have different characteristics. In order to better understand them, I have classified them according to their uses: Fixed solar panels, Portable solar panels.Generally speaking, most of the fixed solar panels are used on the roof. They are exposed to wind and rain every day, and they need to be cleaned and maintained regularly. Therefore, the first thing to do when designing solar panels is to solve the waterproof.
However, many people don’t know how it is waterproof. The following will explain why solar panels are waterproof.
Ordinary solar panels are divided into five layers: photovoltaic glass, EVA layer, solar cell sheet, EVA layer, and back sheet.Photovoltaic glass: photovoltaic (short for solar photovoltaic power generation system, is a new type of power generation system that uses the photovoltaic effect of solar cell semiconductor materials to directly convert solar radiation energy into electrical energy. There are two modes of independent operation and grid-connected operation. ) Glass is one of the important components of solar panels. It is composed of low-iron glass, solar cells, film, back glass, and special metal wires (special tempered glass).
The solar cells are sealed between a piece of low-iron glass and a piece of back glass, it is a novel high-tech glass product for construction. The low-iron glass is used to cover the solar cell to ensure high solar light transmittance.
The tempered low-iron glass is a special use of glass, also has stronger resistance to wind pressure and the ability to withstand large changes in temperature between day and night, so as to improve its light efficiency. The purpose is to improve its light absorption and photoelectric conversion efficiency. The advantages are:
(1)High strength. This is one of the main conditions for solar panels to be waterproof. The strength of low-iron glass is mainly reflected in the bending strength and impact strength. Compared with ordinary glass, the bending strength and impact strength of low-iron glass are respectively normal glass 3-5 times and 5-10 times higher than that, which can better protect the integrated board.
(2)High heat resistance. The temperature difference range that low iron glass can withstand is above 150 degrees Celsius, which is 2-3 times higher than that of ordinary glass. (Solar panel components will generate a lot of heat during use, and poor heat resistance will cause the glass to burst.)
(3)High security. Low-iron glass is not easy to break. When its ability to withstand external forces reaches its limit to cause damage, the fragments will not take on an acute angle, so that greatly reduced to harm the human body (almost no rupture).
EVA layer (transition layer): ethylene and vinyl acetate copolymer film, referred to as EVA, is mainly used as a bonding agent for photovoltaic glass and cells.
Cells (divided into monocrystalline silicon and polycrystalline silicon): The basic device that absorbs solar radiation and converts it into electrical energy to realize the photo-electric conversion pair. It is the core of the solar cell panel, but the cell cannot be used at will, best to use monocrystalline silicon cells with high conversion rate, low cost and long life.
Backplane: It supports the battery, and has reliable insulation, water resistance, and aging resistance. Generally, it has a multi-layer structure (PVDF/PET/PVDF), the outer protective layer PVDF has good resistance to environmental corrosion, the middle layer is a PET polyester film with good insulation properties, and the inner layer PVDF and EVA has good adhesion properties.
The main waterproof function of solar panels is based on the first layer of photovoltaic glass and the last layer of backing. But even if they are stacked on top of each other in this way, rainwater will seep in from the edges. In order to avoid the short circuit of the control circuit inside, which would damage the battery cells, it is necessary to apply Conformal Coating evenly on the edges, because Conformal Coating has outstanding water repellency, high and low temperature resistance. , After curing, it becomes a transparent protective film, which can enhance the moisture-proof, anti-fouling, anti-mildew, waterproof and anti-smoke ability of electronic circuits and components. To prevent corrosion of solder joints and conductors, it can also play a role in shielding and eliminating electromagnetic interference, preventing circuit short-circuits, and improving the insulation performance of circuit boards.
The above is all the components of a fixed solar panel, and a fixed solar panel cannot meet all the needs of life, such as electricity used in mobile activities such as travel, RV, camping, fishing, etc., so portable solar panels have been developed. The main difference between them is the ETFE film. Let us introduce the ETFE film in the portable solar panel in detail:
Portable solar panels are mainly used in field activities. With the development of modern communication technology, the application of electronic communication tools and various electrical appliances in the field is increasing. The supply of power has become a new problem, such as field exploration, field investigation, photography, TV shooting, tourism, picnics, and field military activities. Ordinary batteries cannot be carried in large quantities and their limited capacity. Therefore, portable solar panels are an important way of supplying power in these activities, and because they are easy to carry, store and use, solar panels have been widely used in outdoor activities.
The structure of the portable solar panel and the fixed solar panel are the same, except that the portable solar panel replaces the photovoltaic glass with an ETFE film, which is more convenient to carry and use, and the efficiency of photoelectric conversion will be better. Ethylene tetrafluoroethylene (ETFE) is a fluorine-based plastic. It was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer and its source-based name is poly(ethene-co-tetrafluoroethene). It is also known under the brand name Tefzel. ETFE has a relatively high melting temperature, excellent chemical, electrical and high-energy radiation resistance properties.
Benefits of ETFE film:
(1)Waterproof - ETFE is a copolymer of ethylene and tetrafluoroethylene. The copolymer combines all the advantages of ethylene and tetrafluoroethylene. A major feature of tetrafluoroethylene is that it is insoluble in water, so the ETFE film has waterproof performance.
(2)Solar control/shading - ETFE thin film system can add a variety of glass frit patterns on one or more layers to change its solar performance.
(3)Excellent light transmittance - ETFE film can be highly transparent, allowing sufficient sunlight to pass through.
(4)Durable and durable - ETFE will not degrade after long - term exposure to environmental pollution, ultraviolet rays, irritating chemicals or extreme temperature changes.
(5)Acoustics - ETFE film has approximately 70% acoustic transmission.
(6)Sustainability/Energy Saving - Compared with other similar coating materials, it consumes less energy from film extrusion to transportation to the site, thereby reducing the overall carbon footprint. In addition, the nature of the product enhances the physical building through heat insulation and daylighting, thereby contributing to the global low energy consumption of the building.
(7)Cost-effectiveness - ETFE resins are resistant to ultraviolet light. An artificial weathering test (comparable to 30 years’ exposure) produced almost no signs of film deterioration.
(8)Recyclable - easy to recycle, waste from the manufacturing process and even old ETFE components can be remade into new ETFE products, such as pipe parts, wires or castings.
(9)Elasticity - Although ETFE films are very elastic, they still have structural resistance. The tensile strength at the elastic/plastic limit is 21 - 23N/mm2, but the tensile strength at the breaking point is 52/Nmm2. For membrane structure calculations, the limit of 15 N/mm is usually conservatively adopted, with a working temperature range of 89 K to 423 K (−185 °C to +150 °C or −300 °F to +300 °F).
In summary, ETFE film is far greater than other materials in terms of technology and cost. The ITETHIL store uses ETFE film imported from Japan for the production of solar panels. At present, it is the only seller of 100w 18v folding solar panel using ETFE film in the market. Its main features are: waterproof, easy to clean, easy to carry, storage and high conversion rate, and the price is lower than other non-ETFE film solar panels of the same wattage.
To read more about 100w 18v folding solar panel, click here.