The anti-corrosion measures for photovoltaic street light controllers mainly include the following aspects:
Selection of shell material
Corrosion resistant metal materials:
The shell is made of stainless steel material, such as 304 or 316 stainless steel. 304 stainless steel contains 18% chromium and 8% nickel, which gives it good corrosion resistance in general environments. 316 stainless steel has added molybdenum element, further enhancing its resistance to seawater and chloride corrosion, making it suitable for harsh environments such as coastal areas.
Aluminum alloy is also an option. After anodizing treatment, a dense oxide film will form on the surface of the aluminum alloy shell, which can effectively prevent the aluminum substrate from being corroded. For example, in some urban road photovoltaic street light controllers, 6063 aluminum alloy shells that have been anodized can maintain good stability in environments such as acid rain.
High quality plastic materials:
Use engineering plastics such as ABS (acrylonitrile butadiene styrene copolymer), PC (polycarbonate), or their alloys. ABS plastic has good mechanical properties and corrosion resistance, and is relatively inexpensive. PC plastic has excellent impact resistance and weather resistance, as well as good transparency, and can be used to make controller housings with transparent observation windows. Some high-end photovoltaic street light controllers use PC/ABS alloy shells, which combine the advantages of both and can resist UV radiation, rainwater, and chemical erosion in long-term outdoor environments.
Surface protection treatment
Coating treatment:
Spray paint treatment on the metal shell, and the paint layer can provide physical isolation and chemical protection. For example, using epoxy paint, it has good adhesion and chemical corrosion resistance. First, perform pre-treatment on the metal surface, such as grinding, rust removal, oil removal, etc., then spray epoxy primer, and then spray topcoat as needed. Acrylic paint with weather resistance can be chosen as the topcoat, which can resist the damage of ultraviolet rays, maintain the color and protective performance of the shell.
Adopting hot-dip galvanizing treatment, this method is mainly used for steel shells. Immerse the steel shell into molten zinc solution to evenly cover the surface of the shell with a zinc layer. The zinc layer forms a protective film of zinc compounds in the air. When the surface of the outer shell is damaged, the zinc layer can act as a sacrificial anode and be preferentially corroded, thereby protecting the internal steel structure.
Passivation treatment:
For stainless steel shells, although they have a certain degree of corrosion resistance, passivation treatment can further improve their corrosion resistance. Passivation treatment is the use of chemical methods to form a dense passivation film on the surface of stainless steel, which is mainly composed of chromium oxide. For example, using nitric acid solution to passivate stainless steel shells can enhance the stability of stainless steel in corrosive environments containing chloride ions.
Sealing design
Overall sealing structure:
Design a well sealed casing and use rubber sealing rings to prevent moisture, dust, and corrosive gases from entering the interior of the controller. The material of the sealing ring should be selected according to the specific usage environment. For example, silicone rubber sealing rings can be used in high-temperature environments, which have good resistance to high temperatures and aging; In general, nitrile rubber seals are a good choice as they have good resistance to oils and chemicals.
The joints of the shell are sealed with sealant, which should have good weather resistance and water resistance. For example, using polyurethane sealant can maintain good sealing performance under different temperature and humidity conditions, effectively preventing the intrusion of rainwater and corrosive gases.
Interface sealing:
For various interfaces of the controller, such as photovoltaic panel interface, battery interface, and load interface, waterproof sealing plugs or sealing gaskets should be used for sealing. Waterproof sealed plugs usually have rubber gaskets and locking devices to ensure the sealing of the interface in the connected state. The sealing rubber sleeve can be wrapped around the interface cable to further prevent moisture from entering the interior of the controller along the cable.
Internal circuit board protection
Moisture proof treatment:
Apply moisture-proof paint, such as acrylic resin moisture-proof paint, on the circuit board. This paint can form a protective film on the surface of the circuit board, preventing moisture from condensing on the board and causing short circuits and corrosion. During the coating process, it is necessary to ensure that the paint layer is uniform and covers all electronic components and circuits.
Place a desiccant pack inside the controller, which can absorb moisture from the air and keep the internal environment dry. Common desiccants include silica gel desiccants, which have good moisture absorption properties. When silica gel desiccants absorb moisture, their color changes, and the need to replace the desiccant can be determined by observing the color.
Chemical corrosion prevention:
Special protection should be provided for circuit boards in environments that may come into contact with chemically corrosive gases. For example, using a protective coating on the surface of a circuit board can resist the erosion of acidic or alkaline gases. At the same time, a filtering device is installed at the air inlet of the controller to filter out harmful chemicals in the air and reduce the risk of corrosion to the circuit board.