What are the connection methods for solar aluminum frames?

Connection methods for solar aluminum frames?

The frame of the module must have sufficient strength and stability to ensure that the photovoltaic module operates safely and normally in harsh environments such as strong winds, heavy rain, and blizzards. In addition, the component frame must have a certain anti-corrosion ability to prevent corrosion in high temperature and high humidity areas, which will affect the overall performance of the frame.

At present, the main material used for component frames is aluminum alloy, and the most commonly used aluminum alloy model is 6063-T5 (6063 is the grade of aluminum magnesium alloy, T5 is the heat treatment method), which is required to comply with GB/T16474-1996 “Method for Expressing Wrought Aluminum and Aluminum Alloy Grades”. Aluminum alloy has low density, high strength, good plasticity, and is easy to process into various profiles. It has excellent conductivity, thermal conductivity, and corrosion resistance. After surface treatment, aluminum alloy can form a dense oxide layer on the surface, providing effective corrosion resistance. The surface treatment method of 6063 aluminum magnesium alloy is mainly anodizing, and the thickness of the oxide layer is generally greater than 10 μ M (i.e. AA10 level).

The connection methods for aluminum frames are mainly divided into two types: corner code connection and screw connection. The screw connection is shown in Figure 3-15. Generally, screw holes are pre machined on the short frame, and the aluminum profile on the long frame has a self tapping screw installation structure. During assembly, stainless steel self tapping screws are screwed in from one side of the short frame to connect the long and short frames.

◆ The corner code connection is shown in Figure 3-16, which connects the long and short frames through the interference fit between the L-shaped aluminum profile and the long and short frame cavities.

◆ In order to ensure sufficient strength of the component frame, the following aspects need to be considered when designing profiles:

(1) The height of the profile. The height of the profile has a significant impact on the bending section modulus of the profile. Currently, the height of component profiles from mainstream manufacturers is generally within the range of 30-50mm. The height of the profile will have an impact on production and transportation costs. So the design of profile height should be comprehensively considered;

(2) The wall thickness of the profile section. The wall thickness of the cross-section also affects the strength of the profile. Currently, the wall thickness of the profile is generally required to be greater than 1.5mm, and the design should be combined with the requirements of the installation end, especially paying attention to the wall thickness design of stress concentration areas such as installation holes;

(3) The hardness of the profile. The hardness of profiles is mainly determined by the alloy elements and heat treatment process of the profiles. The hardness of profiles has a significant impact on their yield strength and tensile strength. Currently, it is generally required that the hardness of profiles should be at least HW8 or above, with a yield strength of at least 110MPa and a tensile strength of at least 160MPa.

With the advancement of material technology, there is a trend towards thinner and lighter frame profiles in the future. In situations where installation weight is required, such as roofs, thin profiles can be used; In areas with good climate conditions all year round, the height, wall thickness, hardness and other indicators of the components can be relaxed, which not only reduces the weight of the components but also lowers costs. In addition, plastic frames are also one of the current research objects. Plastic frames mainly face technical challenges in terms of strength, cost, and reliability, which still need to be tested and evaluated in the market.

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