Photovoltaic welding strip adopting invar alloy wire core

Abstract

The invention provides a photovoltaic solder strip adopting an invar alloy wire core, which comprises the invar alloy wire core, a copper layer and a soldering tin layer, the invar alloy wire core, the copper layer and the soldering tin layer form a strip body, the outer surface of the invar alloy wire core is wrapped by the copper layer, and the outer surface of the copper layer is wrapped by the soldering tin layer. The invar alloy wire core is compounded into the welding strip, and the thermal expansion coefficient of the invar alloy is smaller than that of metal copper and soldering tin, so that a good anchoring effect, namely an effect of inhibiting thermal deformation of the copper and the tin, can be achieved, and thermal fatigue damage of thermal expansion of the metal to a solar cell is reduced.

Description

Technical Field

[0001] The invention relates to the field of photovoltaic technology, and in particular to a photovoltaic welding strip using an Invar alloy wire core. Background Art

[0002] The thermal expansion coefficient of silicon is about 2.4*10^-6 / K, the thermal expansion coefficient of copper is about 18.7*10^-6 / K, and the thermal expansion coefficient of tin is about 22.0*10^-6 / K. Due to the large difference in thermal expansion coefficients between metal copper and solar cells, photovoltaic ribbons will bring thermal expansion and contraction stress to solar cells, which may cause bending and deformation of solar cells in severe cases. During the alternating hot and cold conditions of day and night, photovoltaic ribbon welding brings cyclical stress to solar cells, which is a destructive thermal fatigue damage. Therefore, it is necessary to avoid thermal fatigue cracking of photovoltaic ribbons. The thermal expansion coefficient of Invar alloy with low expansion characteristics is about 2.5*10^-6 / K, which is very close to that of silicon and is a good technical direction. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention attempts to overcome the above defects. Therefore, the present invention provides a photovoltaic welding strip using an Invar alloy wire core. The thermal expansion coefficient of the Invar alloy is smaller than that of metal copper and solder, and is very close to the thermal expansion coefficient of elemental silicon. Through the anchoring effect of the Invar alloy, the thermal fatigue damage of the solar cell panel caused by the thermal expansion of the metal is reduced.

[0004] To achieve the above objectives, the present invention is implemented through the following technical scheme: a photovoltaic welding strip using an Invar alloy wire core, comprising the Invar alloy wire core, a copper layer and a solder layer, wherein the Invar alloy wire core, the copper layer and the solder layer constitute a strip body, the outer surface of the Invar alloy wire core is wrapped with a copper layer, and the outer surface of the copper layer is wrapped with a solder layer.

[0005] Furthermore, the diameter of the Invar wire core is 0.01-0.05 mm.

[0006] Furthermore, the copper layer has a thickness of 0.01-0.2 mm.

[0007] Furthermore, the thickness of the solder layer is 0.01-0.03 mm.

[0008] Furthermore, the width of the belt body is 0.2-1 mm.

[0009] Compared with the prior art, the present invention has the following beneficial effects: The Invar alloy wire core is compounded into the solder strip. Since the thermal expansion coefficient of Invar alloy is smaller than that of metal copper and solder, it can play a good anchoring role, that is, it can inhibit the thermal deformation of copper and tin, thereby reducing the thermal fatigue damage of metal thermal expansion to solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 : It is a transverse cross-sectional view of this patent; In the figure: 1. Invar alloy wire core; 2. Solder layer; 3. Copper layer; 4. Strip body. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] The present invention provides a photovoltaic welding ribbon using an Invar alloy wire core, such as Figure 1 As shown, it includes an Invar alloy wire core 1, a copper layer 3 and a solder layer 2. The Invar alloy wire core 1, the copper layer 3 and the solder layer 2 form a strip body 4. The outer surface of the Invar alloy wire core 1 is wrapped with the copper layer 3, and the outer surface of the copper layer 3 is wrapped with the solder layer 2. The diameter of the Invar alloy wire core is 0.01-0.05 mm, the thickness of the copper layer 3 is 0.01-0.2 mm, the thickness of the solder layer 2 is 0.01-0.03 mm, and the width of the strip body 4 is 0.2-1 mm.

[0013] Working principle: The Invar alloy wire core is compounded into the solder strip. Since the thermal expansion coefficient of Invar alloy is smaller than that of metal copper and solder, it can play a good anchoring role, that is, it can inhibit the thermal deformation of copper and tin, thereby reducing the thermal fatigue damage of metal thermal expansion to solar cells. Embodiment 1

[0014] The Invar alloy wire core is pulled into and transported to the electroplating pool, so that a layer of copper is electroplated on the surface of the Invar alloy wire core, and then it is pulled into and the electroplating liquid on the surface is removed by spraying, and then it is blown dry by an air gun, and then it is pulled into and sent to the heating furnace area, which is protected by nitrogen, and then it is pulled into the hot-dip tinning melt pool, and then it is cooled by an air gun and finally rolled up. Embodiment 2

[0015] The Invar alloy wire core is pulled into and transported to the electroplating pool, so that a layer of copper is electroplated on the surface of the Invar alloy wire core, and then it is pulled into and the electroplating liquid on the surface is removed by spraying, and then it is blown dry by an air gun, and then it is pulled into and sent to the heating furnace area, which is protected by nitrogen, and then it is pulled into and flattened by rollers to become a flat wire, and then it is pulled into the hot-dip tinning melt pool, and then it is cooled by an air gun and finally rolled up.

[0016] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A photovoltaic welding ribbon using an Invar alloy ribbon core, characterized in that: The invention comprises an Invar alloy wire core (1), a copper layer (3) and a solder layer (2); the Invar alloy wire core (1), the copper layer (3) and the solder layer (2) form a strip body (4); the outer surface of the Invar alloy wire core (1) is wrapped with the copper layer (3), and the outer surface of the copper layer (3) is wrapped with the solder layer (2).

2. A photovoltaic welding ribbon using an Invar alloy core according to claim 1, characterized in that: The diameter of the Invar wire core is 0.01-0.05 mm.

3. A photovoltaic welding ribbon using an Invar alloy core according to claim 1, characterized in that: The copper layer (3) has a thickness of 0.01-0.2 mm.

4. The photovoltaic welding ribbon using an Invar alloy core according to claim 1, characterized in that: The thickness of the solder layer (2) is 0.01-0.03 mm.

5. The photovoltaic welding ribbon using an Invar alloy core according to claim 1, characterized in that: The width of the belt body (4) is 0.2-1 mm.

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