V-shaped copper-aluminum composite strip for photovoltaics and its production process

Abstract

The present invention discloses a V-shaped copper-aluminum composite strip for photovoltaics and a production process thereof, comprising the following steps: (a) rolling copper strip, (b) rolling aluminum strip, (c) composite forming and (d) V-shaped surface forming; step (a) rolling copper strip, processing oxygen-free copper wire to obtain copper strip, step (b) rolling aluminum strip, processing aluminum strip to obtain aluminum strip; step (c) composite forming, cold rolling and composite the copper strip obtained by rolling copper strip in step (a) and the aluminum strip obtained by rolling aluminum strip in step (b) to obtain copper-aluminum composite strip; step (d) V-shaped surface forming, rolling and forming on the surface of the aluminum strip of the copper-aluminum composite strip to form a V-shaped groove to obtain a V-shaped copper-aluminum composite strip. The present invention realizes copper-aluminum composite, has a conductive property close to that of copper materials, and saves a large amount of copper resources; the V-shaped copper-aluminum composite strip can reflect sunlight irradiated on the surface, and can reach the battery surface through secondary reflection, so that the sunlight can be reused, thereby improving the utilization rate of sunlight.

Description

Technical Field

[0001] The present invention relates to a photovoltaic copper strip, and more specifically, to a production process of a photovoltaic V-shaped copper-aluminum composite strip, and also to a photovoltaic V-shaped copper-aluminum composite strip produced by the process. Background Art

[0002] Copper tape is an important component in photovoltaic modules and a key material for connecting solar cells. Solar cells are connected by copper tape to form a complete electrical path. Light energy is converted into electrical energy through solar cells, and the generated current forms a transmission circuit through copper tape, providing a path basis for utilizing solar energy. Copper tape plays the role of conductive link and heat dissipation channel in photovoltaic modules.

[0003] In order to achieve welding between the copper strip and the solar cell, a tin layer is plated on the surface of the copper strip. After tinning, the surface of the copper strip is a plane that is approximately mirror-like. The light entering the component is incident on the surface and will be reflected by the mirror and cannot be used, thereby reducing the light intensity and causing the loss of sunlight.

[0004] In addition, the cost of copper strips is relatively high, while the performance of copper-aluminum composite materials is close to that of copper materials, and can be used as a substitute for copper materials, which can greatly reduce the material cost. However, the thickness of copper strips used for photovoltaics is relatively thin, and the current copper-aluminum composite process cannot meet the requirements of photovoltaic conductive strips.

[0005] Therefore, a new solution needs to be proposed to solve this problem. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a V-shaped copper-aluminum composite strip for photovoltaics and a production process thereof.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A process for producing a V-shaped copper-aluminum composite strip for photovoltaic use, comprising the following steps: (a) rolling a copper strip, (b) rolling an aluminum strip, (c) composite forming, and (d) V-shaped surface forming;

[0009] Step (a) rolling copper strips to process oxygen-free copper wires to obtain copper strips; step (b) rolling aluminum strips to process aluminum wires to obtain aluminum strips, wherein the widths of the processed copper strips and aluminum strips are adapted;

[0010] Step (c) composite forming, after step (a) rolling the copper strip and step (b), cold rolling the copper strip obtained by rolling the copper strip in step (a) and the aluminum strip obtained by rolling the aluminum strip in step (b) to obtain a copper-aluminum composite strip;

[0011] The step (c) composite forming includes the following steps: (c1) cold rolling composite, (c2) online annealing, (c3) drying, (c4) continuous rolling, (c5) online annealing, and (c6) drying; the step (c1) cold rolling composite includes the following steps: (c11) aluminum strip grinding, (c12) copper strip grinding, (c13) copper strip twisting, and (c14) lamination composite;

[0012] Steps (c11) of polishing the aluminum strip and (c12) of polishing the copper strip include polishing the composite surface of the aluminum strip and the composite surface of the copper strip, respectively, to form grooves distributed along the length direction of the strip body after polishing; step (c13) of twisting the copper strip includes twisting the copper strip obtained by polishing the copper strip (c12), during which the composite surface of the copper strip will bend to form an arc-shaped bulge;

[0013] Step (d) V-shaped surface forming: after step (c) composite forming, rolling forming is performed on the surface of the aluminum strip of the copper-aluminum composite strip to form a V-shaped groove to obtain a V-shaped copper-aluminum composite strip.

[0014] The present invention is further configured that, in the step (c13) of twisting the copper strip, the twisting angle of the copper strip is 5°-15°;

[0015] The step of stacking and compounding (c14) is to stack the copper strip obtained by twisting the copper strip (c13) and the aluminum strip obtained by grinding the aluminum strip (c11) on each other, stack the composite surface of the copper strip and the composite surface of the aluminum strip obtained by grinding, and cold-roll the copper strip and the aluminum strip to compound.

[0016] The present invention is further configured as follows: step (a) rolling a copper strip, the copper strip manufactured has a thickness of 1 mm and a width of 6 mm; step (b) rolling an aluminum strip, the aluminum strip manufactured has a thickness of 4 mm and a width of 6 mm.

[0017] The present invention is further configured as follows: (c1) after cold rolling and compounding, the thickness of the copper-aluminum composite strip is 1.25 mm; the cold rolling and compounding processing rate is greater than 70%, and the weight proportion of the copper strip in the copper-aluminum composite strip is 40% to 50%.

[0018] The present invention is further configured as follows: (c4) the continuous rolling step is that the continuous rolling passes are 2 to 5 times, and the rolling processing rate of each pass is 20% to 50%; after (c4) continuous rolling, the thickness of the copper-aluminum composite strip is 0.35 mm.

[0019] The present invention is further configured such that (d) V-shaped surface forming includes the following steps: (d1) rolling forming, (d2) online annealing, (d3) drying, and (d4) winding; the step of (d1) rolling forming is to use a V-shaped surface forming roller group to roll-form the (c) composite-formed copper-aluminum composite strip to form a V-shaped groove (211) on the aluminum strip surface of the copper-aluminum composite strip to obtain a V-shaped copper-aluminum composite strip.

[0020] The present invention is further configured such that the height H of the V-shaped groove (211) is 0.037 mm±0.002 mm, and the angle of the V-shaped groove (211) is 117°±2°.

[0021] The present invention is further configured such that, in the V-shaped copper-aluminum composite strip, a diffusion layer is formed at the bonding interface between the copper strip and the aluminum strip, and the thickness of the diffusion layer is less than 3 μm.

[0022] The present invention is further configured such that, in the step (c13) of twisting the copper strip, a twisting device is used to twist the copper strip, and the twisting device includes a limit roller group 1, a limit roller group 2 and a twisting roller group. The limit roller group 1 and the limit roller group 2 are horizontally arranged along the conveying direction of the copper strip, and the twisting roller group is located between the limit roller group 1 and the limit roller group 2. The twisting roller group includes two twisting rollers arranged in parallel up and down, and a twisting gap is formed between the two twisting rollers for the copper strip to pass through; an inclination angle B is formed between the axis of the twisting roller and the horizontal plane. During the conveying process, the copper strip is input from the original horizontal direction to between the two twisting rollers, and the copper strip is tilted and twisted.

[0023] The present invention also provides a V-shaped copper-aluminum composite belt for photovoltaics, which is processed by the above production process to obtain a V-shaped copper-aluminum composite belt. The V-shaped copper-aluminum composite belt realizes copper-aluminum composite, has a conductivity close to that of copper materials, saves copper materials, can reduce the cost of the composite belt, and saves a large amount of copper resources. Moreover, the V-shaped copper-aluminum composite belt can reflect sunlight irradiated on the surface, and can reach the battery surface through secondary reflection, so that the sunlight can be reused, thereby improving the utilization rate of sunlight, increasing the light intensity, and reducing the loss of radiation.

[0024] Before cold rolling and laminating, the surfaces of the copper and aluminum strips to be laminated are first polished. During the polishing process, rough grooves can be formed on the composite surfaces of the copper and aluminum strips, and the grooves are arranged roughly along the length direction of the strips. During the laminating process, the composite surfaces of the copper and aluminum strips with grooves fit together, and the concave and convex groove parts can fit together. Moreover, after fitting together, the bite strength of the contact surfaces of the two strips can be improved, thereby improving the strength performance of the copper and aluminum strips when they are laminated.

[0025] After polishing, the copper strip is twisted, and the twist axis is roughly along the length direction of the strip. During the twisting process, the copper strip composite surface will bend and form an arc-shaped bulge. During the twisting process, the copper strip composite surface will change from the original plane to a similar arc-shaped convex surface, and become longer along the width direction of the copper strip, and the grooves on the copper strip composite surface will be slightly torn and expanded. The grooves on the expanded aluminum strip composite surface can be more easily embedded in the copper strip composite surface, and the copper strip and aluminum strip are more interlocked, thereby improving the composite strength and performance of the two. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The process flow chart of a production process of a V-shaped copper-aluminum composite strip for photovoltaic use in Example 1;

[0027] Figure 2 This is a process flow chart of V-shaped surface forming in step (d) of Example 1;

[0028] Figure 3 This is a process flow chart of composite molding in step (c) of Example 1;

[0029] Figure 4 This is a schematic diagram of the structure of the copper strip and the aluminum strip stacked in Example 1;

[0030] Figure 5 This is a schematic diagram of the structure of the V-shaped surface forming in Example 1;

[0031] Figure 6 Schematic diagram of the cross section of the V-shaped copper-aluminum composite strip in Example 1;

[0032] Figure 7 for Figure 6 Enlarged view of point A in the middle;

[0033] Figure 8 This is an enlarged schematic diagram of the copper strip and the aluminum strip after being polished in Example 1;

[0034] Fig. 9 This is a process flow chart of cold rolling and laminating in step (c1) of Example 2;

[0035] Fig.10 This is a schematic diagram of the structure of the copper strip twisting in Example 2;

[0036] Fig.11 It is a structural schematic diagram of the twisting device in the second embodiment;

[0037] Fig.12 The structure of the twisting roller group in the second embodiment is shown in FIG. Figure 1 ;

[0038] Fig.13 The structure of the twisting roller group in the second embodiment is shown in FIG. Figure 2 ;

[0039] Fig.14 Schematic diagram of the structure of the diffusion layer of the copper strip and the aluminum strip in Example 1.

[0040] Figure numerals: copper strip 1; copper strip composite surface 11; groove one 111; side one 101; side two 102; aluminum strip 2; V-shaped surface 21; V-shaped groove 211; aluminum strip composite surface 22; groove two 221; V-shaped surface forming roller group 3; V-shaped roller 31; V-shaped mold 311; flat roller 32; limiting roller group one 4; limiting roller group two 5; torsion roller group 6; torsion roller 61; torsion gap 62; support frame 63; sliding frame 64; frame 65; hydraulic cylinder 66; guide roller group 7. DETAILED DESCRIPTION

[0041] 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.

[0042] Embodiment 1

[0043] This embodiment discloses a production process of a V-shaped copper-aluminum composite strip for photovoltaic use, referring to Figure 1 As shown, the steps include: (a) rolling copper strip, (b) rolling aluminum strip, (c) composite forming and (d) V-shaped surface forming.

[0044] Wherein, in step (a), the copper strip is rolled, and in order to process the copper strip, the oxygen-free copper wire is processed to obtain the copper strip; when processing the copper strip, the oxygen-free copper wire is used as the raw material, the diameter of the oxygen-free copper wire is 3mm to 8mm, the copper content of the oxygen-free copper wire is greater than 99.99%, the oxygen content is less than 5ppm, the tensile strength is greater than 200MPa, and the elongation is greater than 50%. The size parameters of the manufactured copper strip can be specifically set according to the material requirements. For example, in this embodiment, the manufactured copper strip has a thickness of 1mm and a width of 6mm.

[0045] Step (b) rolling the aluminum strip, in order to process the aluminum strip, the aluminum strip is processed to obtain the aluminum strip; when processing the aluminum strip, aluminum wire is used as the raw material, the diameter of the aluminum wire is 8mm to 12.5mm, the aluminum content of the aluminum wire is greater than 99.99%, the tensile strength is greater than 100MPa, and the elongation is greater than 25%. The size parameters of the manufactured aluminum strip can be specifically set according to the material requirements. For example, in this embodiment, the thickness of the manufactured aluminum strip is 4mm and the width is 6mm.

[0046] There is no particular order in which the copper strip is rolled in step (a) and the aluminum strip is rolled in step (b), and the copper strip 1 and the aluminum strip 2 having matching widths can be obtained respectively.

[0047] Step (c) composite forming, after step (a) rolling the copper strip and step (b), the copper strip 1 obtained by rolling the copper strip in step (a) and the aluminum strip 2 obtained by rolling the aluminum strip in step (b) are cold rolled to obtain a copper-aluminum composite strip, referring to Figure 4 shown.

[0048] Step (d) V-shaped surface forming: after step (c) composite forming, the aluminum strip surface of the copper-aluminum composite strip is rolled to form a V-shaped groove 211 to obtain a V-shaped copper-aluminum composite strip. Figure 5-Figure 7 As shown in FIG. 1 , the thickness of the copper-aluminum composite strip is 1.25 mm.

[0049] In this embodiment, step (a) rolling the copper strip includes the following steps: (a1) drawing, (a2) rolling, (a3) ​​drawing, (a4) rolling, (a5) rolling, (a6) drawing, (a7) rolling, (a8) drawing, (a9) online annealing, (a10) drying, and (a11) winding.

[0050] (a1) The drawing step is: drawing the oxygen-free copper wire with a diameter of 3 mm to 8 mm to a diameter of 1.2 mm to 2.9 mm at a drawing speed of 125 m / min to 130 m / min;

[0051] (a2) the step of rolling comprises: rolling the oxygen-free copper wire drawn in (a1) to obtain a copper strip, wherein the rolling reduction is 0.35 mm to 0.55 mm;

[0052] (a3) the step of drawing comprises: drawing the copper strip obtained by drawing in (a1), wherein the drawing amount of the copper strip width is 0.06 mm to 0.08 mm, and the drawing amount of the copper strip thickness is 0.015 mm to 0.045 mm;

[0053] (a4) the step of rolling comprises: rolling the copper strip drawn in (a3) ​​with a rolling reduction of 0.06 mm to 0.2 mm;

[0054] (a5) the step of rolling comprises: rolling the copper strip obtained by rolling in (a4) with a rolling reduction of 0.06 mm to 0.2 mm;

[0055] (a6) the step of drawing comprises: drawing the copper strip obtained by rolling in (a5), wherein the drawing amount of the copper strip width is 0.06 mm to 0.08 mm, and the drawing amount of the copper strip thickness is 0.015 mm to 0.045 mm;

[0056] (a7) the step of rolling comprises: rolling the copper strip drawn in (a6) with a rolling reduction of 0.06 mm to 0.2 mm;

[0057] (a8) the step of drawing is: (a7) drawing the copper strip obtained by rolling, wherein the drawing amount of the copper strip width is 0.06 mm to 0.08 mm, and the drawing amount of the copper strip thickness is 0.06 mm to 0.08 mm;

[0058] (a9) The online annealing step is: first conduction heating, then water annealing, the voltage of the conduction heating is 15-17V, the current is 500A-700A, the time of the conduction heating is 0.6-1.2 seconds, and the temperature of the copper strip after the conduction heating is 750-800 degrees; the time of water annealing is 0.3-0.6 seconds, and the temperature of the copper strip after leaving the water is ≤50 degrees; (a9) In the online annealing step, nitrogen protection measures are adopted to prevent oxidation of the surface of the copper strip;

[0059] (a10) drying step comprises: drying the copper strip obtained by online annealing in (a9) at a temperature of 75 to 80 degrees for a drying time of 3 to 5 seconds;

[0060] (a11) The winding step is: winding the copper strip obtained by drying (a10) with a winding force of 35N to 55N.

[0061] In step (a) of rolling the copper strip, the copper strip has a thickness of 1 mm and a width of 6 mm.

[0062] In this embodiment, step (b) rolling the aluminum strip includes the following steps: (b1) drawing, (b2) rolling, (b3) drawing, (b4) rolling, (b5) rolling, (b6) drawing, (b7) rolling, (b8) drawing, (b9) online annealing, (b10) drying, and (b11) winding.

[0063] (b1) the drawing step comprises: drawing the aluminum wire having a diameter of 8 mm to 12.5 mm to a diameter of 2 mm to 5 mm at a drawing speed of 125 m / min to 150 m / min;

[0064] (b2) the step of rolling comprises: rolling the aluminum wire drawn in (b1) to obtain an aluminum strip, wherein the rolling reduction is 0.5 mm to 1 mm;

[0065] (b3) the step of drawing comprises: drawing the aluminum strip obtained by rolling in (b2), wherein the drawing amount of the aluminum strip width is 0.2 mm to 0.3 mm, and the drawing amount of the aluminum strip thickness is 0.06 mm to 0.10 mm;

[0066] (b4) the step of rolling comprises: rolling the aluminum strip drawn in (b3) with a rolling reduction of 0.5 mm to 1 mm;

[0067] (b5) the step of rolling comprises: rolling the aluminum strip obtained by rolling (b4) with a rolling reduction of 0.5 mm to 1 mm;

[0068] (b6) the step of drawing comprises: drawing the aluminum strip obtained by rolling in (b5), wherein the drawing amount of the aluminum strip width is 0.2 mm to 0.3 mm, and the drawing amount of the aluminum strip thickness is 0.06 mm to 0.10 mm;

[0069] (b7) the step of rolling comprises: rolling the aluminum strip drawn in (b6) with a rolling reduction of 0.5 mm to 1 mm;

[0070] (b8) the step of drawing comprises: drawing the aluminum strip obtained by rolling in (b7), wherein the drawing amount of the aluminum strip width is 0.2 mm to 0.3 mm, and the drawing amount of the aluminum strip thickness is 0.06 mm to 0.10 mm;

[0071] (b9) The steps of online annealing are: firstly conducting heating, then annealing in water, the voltage of conducting heating is 5-12V, the current is 200-500A, the time of conducting heating is 0.5-1.5 seconds, and the temperature of the aluminum strip after conducting heating is 300-400 degrees; the time of annealing in water is 0.3-0.6 seconds, and the temperature of the aluminum strip after leaving the water is ≤50 degrees;

[0072] (b10) drying step comprises: drying the aluminum strip obtained by online annealing in (b9) at a temperature of 55 to 65 degrees and a drying time of 3 to 5 seconds;

[0073] (b11) The winding step is: winding the aluminum strip obtained by drying (b10) with a winding force of 35N to 55N.

[0074] In step (b) of rolling the aluminum strip, the aluminum strip produced has a thickness of 4 mm and a width of 6 mm.

[0075] In this embodiment, refer to Figure 3 As shown, step (c) composite forming includes the following steps: (c1) cold rolling composite, (c2) online annealing, (c3) drying, (c4) continuous rolling, (c5) online annealing, and (c6) drying.

[0076] (c1) The step of cold rolling and laminating is: cold rolling and laminating the copper strip and the aluminum strip to obtain a copper-aluminum composite strip. After cold rolling and laminating, the copper-aluminum composite strip has a thickness of 1.25 mm.

[0077] (c1) Before cold rolling and laminating, the surfaces of the copper strip and the aluminum strip to be laminated are first polished with a wire brush, and the polishing direction is consistent with the cold rolling direction. During the polishing process, the wire brush can form rough grooves on the composite surface of the copper strip and the aluminum strip, and the grooves are arranged roughly along the length direction of the strip body. After polishing, the surface of the copper strip and the aluminum strip is purged to make the surface clean and free of powder.

[0078] Reference Figure 8As shown, after polishing, a groove 111 is formed on the surface of the copper strip composite surface 11, and a groove 221 is formed on the aluminum strip composite surface 22. The groove 111 and the groove 221 can be partially interlocked when stacked. Moreover, after being interlocked, the bite strength of the contact surfaces of the two strips can be improved, thereby improving the strength performance of the copper strip 1 and the aluminum strip 2 when they are composited.

[0079] The cold rolling composite processing rate is greater than 70%, and the weight proportion of copper strip in the copper-aluminum composite strip is 40% to 50%.

[0080] (c2) The online annealing step is to first conduction heat and then enter water for annealing. The voltage of the conductive heating is 12-15V, the current is 300-450A, the time of the conductive heating is 0.5-1.5 seconds, and the temperature of the copper-aluminum composite strip after the conductive heating is 350-450 degrees; the time of entering water for annealing is 0.3-0.6 seconds, and the temperature of the copper-aluminum composite strip after exiting the water is ≤50 degrees; in the online annealing step (c2), nitrogen protection measures are adopted to prevent oxidation of the surface of the copper-aluminum composite strip;

[0081] (c3) drying step is to dry the copper-aluminum composite strip obtained by online annealing in (c2) at a temperature of 80° C. to 90° C. for a time of 1 to 2 seconds;

[0082] (c4) The continuous rolling step is that the continuous rolling passes are 2 to 5 times, and the rolling processing rate of each pass is 20% to 50%; the thickness of the copper-aluminum composite strip after continuous rolling is 0.35 mm.

[0083] (c5) The online annealing step is to first conduction heat and then anneal in water. The voltage of the conductive heating is 12-15V, the current is 300-450A, the time of the conductive heating is 0.5-1.5 seconds, and the temperature of the copper-aluminum composite strip after the conductive heating is 350-450 degrees; the time of annealing in water is 0.3-0.6 seconds, and the temperature of the copper-aluminum composite strip after exiting the water is ≤50 degrees; in the online annealing step (c5), nitrogen protection measures are adopted to prevent oxidation of the surface of the copper-aluminum composite strip; in the copper-aluminum composite strip, a diffusion layer is formed at the bonding interface of the copper strip and the aluminum strip, and the thickness of the diffusion layer is less than 3μm, referring to Fig.14 shown.

[0084] (c6) a drying step of drying the copper-aluminum composite strip obtained by online annealing in (c5) at a temperature of 80 to 90 degrees for a drying time of 1 to 2 seconds;

[0085] In this embodiment, refer to Figure 2 As shown, (d) V-shaped surface forming includes the following steps: (d1) rolling forming, (d2) online annealing, (d3) drying, and (d4) winding.

[0086] The step of rolling (d1) is to roll-form the copper-aluminum composite strip (c) by using a V-shaped surface forming roller group 3 to form a V-shaped groove 211 on the surface of the aluminum strip 2 of the copper-aluminum composite strip to obtain a V-shaped copper-aluminum composite strip.

[0087] Reference Figure 7 As shown, the height H of the V-shaped groove 211 is 0.037 mm ± 0.002 mm, the angle of the V-shaped groove 211 is 117° ± 2°, and the designed height H of the V-shaped groove 211 is 0.038 mm, and the angle is 118°. The V-shaped groove 211 can form an emission angle on the surface of the V-shaped copper-aluminum composite strip, and can reflect sunlight for a second time, so that sunlight can be reused, thereby improving the utilization rate of sunlight, increasing the light intensity, and reducing the radiation loss.

[0088] Reference Figure 5 As shown, the forming roller group 3 includes a V-shaped roller 31 and a flat roller 32, and the V-shaped roller 31 and the flat roller 32 are formed and arranged to form a gap for the copper-aluminum composite strip to pass through. The outer periphery of the V-shaped roller 31 is formed with a V-shaped die 311, and the V-shaped die 311 can roll the surface of the aluminum strip 2 of the copper-aluminum composite strip, thereby forming a V-shaped groove 211.

[0089] (d2) The online annealing step is to first conduction heat and then enter water for annealing. The voltage of the conductive heating is 12-15V, the current is 300-450A, the time of the conductive heating is 0.5-1.5 seconds, and the temperature of the V-shaped copper-aluminum composite strip after the conductive heating is 350-450 degrees; the time of the water annealing is 0.3-0.6 seconds, and the temperature of the V-shaped copper-aluminum composite strip after exiting the water is ≤50 degrees; in the online annealing step (d2), nitrogen protection measures are adopted to prevent oxidation of the surface of the V-shaped copper-aluminum composite strip; the thickness of the diffusion layer at the interface of the V-shaped copper-aluminum composite strip is less than 3μm;

[0090] (d3) drying step is to dry the V-shaped copper-aluminum composite strip obtained by online annealing in (d2) at a temperature of 80 to 90 degrees and a drying time of 1 to 2 seconds;

[0091] (d4) winding the V-shaped copper-aluminum composite strip obtained by drying in (d3) with a winding force of 35N to 55N.

[0092] This embodiment also discloses a V-shaped copper-aluminum composite belt for photovoltaics, which is processed by the above production process to obtain a V-shaped copper-aluminum composite belt. In this embodiment, the V-shaped copper-aluminum composite belt realizes copper-aluminum composite, has a conductivity close to that of copper materials, saves copper materials, can reduce the cost of the composite belt, and saves a large amount of copper resources. Moreover, the V-shaped copper-aluminum composite belt can reflect the sunlight irradiated on the surface, and can reach the battery surface through secondary reflection, so that the sunlight can be reused, thereby improving the utilization rate of sunlight, increasing the light intensity, and reducing the loss of irradiation.

[0093] Embodiment 2

[0094] This embodiment discloses a production process of a V-shaped copper-aluminum composite strip for photovoltaics. On the basis of the first embodiment, the process of cold rolling composite in step (c1) is improved, thereby improving the composite strength between the copper strip and the aluminum strip.

[0095] (c1) The step of cold rolling and bonding is: cold rolling and bonding the copper strip and the aluminum strip to obtain a copper-aluminum composite strip.

[0096] Reference Fig. 9 As shown, step (c1) cold rolling composite includes the following steps: (c11) aluminum strip grinding, (c12) copper strip grinding, (c13) copper strip twisting and (c14) lamination composite.

[0097] (c11) The step of grinding the aluminum strip is to grind the surface of the aluminum strip 2 obtained by rolling the aluminum strip in step (b), and use a wire brush to grind the composite surface 22 of the aluminum strip, and the grinding direction is consistent with the cold rolling direction. During the grinding process, the wire brush can form rough grooves 221 on the composite surface of the aluminum strip 2, and the grooves 221 are arranged roughly along the length direction of the strip body. After grinding, the surfaces of the copper strip and the aluminum strip are purged to make their surfaces clean and free of powder.

[0098] (c12) The step of grinding the copper strip is to grind the surface of the copper strip 1 obtained by rolling the copper strip in step (a), and use a wire brush to grind the composite surface 11 of the copper strip, and the grinding direction is consistent with the cold rolling direction. During the grinding process, the wire brush can form a rough groove 111 on the composite surface of the copper strip 1, and the groove 111 is arranged roughly along the length direction of the strip body. After grinding, the surface of the copper strip and the aluminum strip is purged to make the surface clean and free of powder.

[0099] Reference Figure 8 As shown, during the compounding, the polished copper strip composite surface 11 and the aluminum strip composite surface 22 are compounded with each other, and the groove 1 111 and the groove 2 221 form a convex and concave gully structure, which can be interlocked to improve the bonding strength between the copper strip 1 and the aluminum strip 2.

[0100] Reference Fig.10As shown, the step of twisting the copper strip (c13) is to twist the copper strip 1 obtained by grinding the copper strip (c12), and the twisting axis is roughly along the length direction of the strip body. During the twisting process, the copper strip composite surface 11 will bend and form an arc-shaped bulge. During the twisting process, the copper strip composite surface 11 will change from the original plane to a similar arc-shaped convex surface, and become longer along the width direction of the copper strip 1, and the groove 1 111 of the copper strip composite surface 11 will be slightly torn and expanded. The groove 2 221 part of the expanded aluminum strip composite surface 22 can be more easily embedded in the copper strip composite surface 11, and the copper strip 1 and the aluminum strip 2 are more interlocked, thereby improving the composite strength and performance of the two.

[0101] The step of stacking and compounding (c14) is to stack the copper strip 1 obtained by twisting the copper strip (c13) and the aluminum strip 2 obtained by grinding the aluminum strip (c11) on each other, with the copper strip composite surface 11 and the aluminum strip composite surface 22 stacked, and the copper strip 1 and the aluminum strip 2 are cold-rolled and compounded.

[0102] This embodiment also discloses a twisting device for implementing the step (c13) of twisting the copper strip, which can twist the copper strip 1, referring to Figure 11-13 Provide explanation.

[0103] Reference Fig.11 As shown, the twisting device includes a limit roller group 1 4, a limit roller group 2 5 and a twisting roller group 6. The limit roller group 1 4 and the limit roller group 2 5 are arranged along the conveying direction of the copper strip 1, and each includes an upper and lower limit roller, which can press and limit the upper and lower sides of the copper strip 1. The limit rollers are arranged in a horizontal direction, so that the copper strip 1 can be conveyed roughly in a horizontal direction.

[0104] Reference Fig.11 , Fig.12 As shown, the twist roller set 6 is located between the limit roller set 1 4 and the limit roller set 2 5. The twist roller set 6 includes two twist rollers 61 stacked up and down. The twist rollers 61 are parallel to each other and are in an inclined state. The axis of the twist rollers 61 forms an inclination angle B with the horizontal plane. The inclination angle B is about 10°, generally in the range of 5-15°. A twist gap 62 is formed between the two twist rollers 61 for the copper strip 1 to pass through.

[0105] During the conveying process, the copper strip 1 is inputted between the two twisting rollers 61 from the original horizontal direction. In the cross-sectional direction, the copper strip 1 will be tilted and twisted, thereby causing the copper strip 1 to be twisted.

[0106] Reference Fig.11As shown, the two limiting rollers of the limiting roller group 2 5 can accommodate the copper strip 1 and the aluminum strip 2 at the same time. The aluminum strip 2 is transported at the lower side of the copper strip 1 and can also be input to the limiting roller group 2 5 through the guiding effect of the guide roller group 7, and the aluminum strip composite surface 22 is facing and can be mutually attached to the copper strip composite surface 11. The copper strip 1 and the aluminum strip 2 can be cold rolled and composited by continuing to transport backward from the limiting roller group 2 5.

[0107] Reference Fig.12 As shown, in the cross-sectional direction of the copper strip 1, the twisted copper strip 1 has two sides, one side is the side 101, and the other side is the side 2 102, and the height of the side 2 102 is higher than the side 101. Among them, the height of the side 101 is consistent with the height of the copper strip transported in the horizontal direction, and the height of the side 2 102 is higher than the copper strip transported in the horizontal direction. From the overall point of view, the copper strip 1 can be roughly regarded as rotating and flipping upward from the position of the side 2 102 during the twisting process. During the flipping process, the lower side of the copper strip 1 (i.e., the copper strip composite surface 11) will produce a slightly arc-shaped bend. During the bending process, the groove 111 of the copper strip composite surface 11 can be slightly torn and expanded, which is beneficial to the subsequent copper-aluminum composite treatment.

[0108] Reference Fig.13 As shown, the twisting roller set 6 can be further designed so that the twisting roller set 6 can be adjusted in lateral displacement and rotation, so that the inclination angle and lateral position of the torsion gap 62 can meet the torsion requirements of the copper strip.

[0109] Specifically, the twisting roller group 6 is rotatably mounted on the support frame 63, which can support the support frame 63 as a whole and maintain the position stability of the two twisting rollers 61. A frame 65 and a sliding frame 64 are arranged at the lower part of the support frame 63. The frame 65 serves as a supporting carrier at the bottom. The sliding frame 64 is horizontally slidably connected to the frame 65, and the sliding direction is approximately perpendicular to the conveying direction of the copper strip 1. In addition, the support frame 63 is located at the upper part of the sliding frame 64. One side of the support frame 63 is rotatably connected to the sliding frame 64, and a hydraulic cylinder 66 is installed on the other side. The support frame 63 can be supported by the hydraulic cylinder 66. By adjusting the extension and contraction amount of the hydraulic cylinder 66, the support frame 63 and the entire twisting roller group 6 can be tilted and adjusted.

[0110] By combining the lateral adjustment and the rotation adjustment, the position of the torsion gap 62 can be adjusted to meet the requirements of the height position of the side 101 and the side 2 102 of the copper strip 1. During the rotation adjustment of the support frame 63 and the torsion roller group 6, since the rotation center has a certain offset from the position of the side 101 of the copper strip 1, the position (especially the height) of the side 101 of the copper strip 1 will change during the rotation adjustment, and it is impossible to maintain the requirement of being close to the height of the straight section of the copper strip 1. By sliding the sliding frame 64 laterally, the torsion roller group 6 can be offset as a whole, and the corresponding torsion gap 62 in the torsion roller group 6 will also move synchronously, so that the torsion gap 62 can be adapted to the position corresponding to the path of the copper strip 1, and the height of the side 101 of the copper strip 1 can be basically maintained. The side 2 102 of the copper strip 1 is twisted upward, and the copper strip composite surface 11 on the lower side of the copper strip 1 can be stably twisted to ensure the subsequent composite strength and stability of the copper strip 1 and the aluminum strip 2.

[0111] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A process for producing a V-shaped copper-aluminum composite strip for photovoltaic use, characterized in that: The method comprises the following steps: (a) rolling a copper strip, (b) rolling an aluminum strip, (c) composite forming and (d) V-shaped surface forming; Step (a) rolling copper strips to process oxygen-free copper wires to obtain copper strips; step (b) rolling aluminum strips to process aluminum wires to obtain aluminum strips, wherein the widths of the processed copper strips and aluminum strips are adapted; Step (c) composite forming, after step (a) rolling the copper strip and step (b), cold rolling the copper strip obtained by rolling the copper strip in step (a) and the aluminum strip obtained by rolling the aluminum strip in step (b) to obtain a copper-aluminum composite strip; The step (c) composite forming includes the following steps: (c1) cold rolling composite, (c2) online annealing, (c3) drying, (c4) continuous rolling, (c5) online annealing, and (c6) drying; the step (c1) cold rolling composite includes the following steps: (c11) aluminum strip grinding, (c12) copper strip grinding, (c13) copper strip twisting, and (c14) lamination composite; Step (c11) aluminum strip polishing and step (c12) copper strip polishing, polishing the aluminum strip composite surface and the copper strip composite surface respectively, forming grooves distributed along the length direction of the strip body after polishing; forming groove 1 (111) on the surface of the copper strip composite surface (11), and forming groove 2 (221) on the surface of the aluminum strip composite surface (22), groove 1 (111) and groove 2 (221) forming a convex and concave gully-like structure that can be interlocked; The step of twisting the copper strip (c13) is to twist the copper strip (1) obtained by grinding the copper strip (c12), and during the twisting process, the composite surface of the copper strip will bend to form an arc-shaped bulge; during the twisting process, the composite surface (11) of the copper strip will change from an original plane to an arc-shaped convex surface, and will become longer along the width direction of the copper strip (1), and the groove 1 (111) of the composite surface (11) of the copper strip will be torn and expanded; In the cross-sectional direction of the copper belt (1), the twisted copper belt (1) has two side edges, one side is side edge 1 (101), and the other side is side edge 2 (102), and the height of side edge 2 (102) is higher than that of side edge 1 (101), the height of side edge 1 (101) is consistent with the height of the copper belt transported in the horizontal direction, and the height of side edge 2 (102) is higher than the belt body transported in the horizontal direction; during the twisting process, the copper belt (1) rotates upward from the position of side edge 2 (102), and during the flipping process, the lower side of the copper belt (1) will generate an arc-shaped bend; Step (d) V-shaped surface forming: after step (c) composite forming, rolling forming is performed on the surface of the aluminum strip of the copper-aluminum composite strip to form a V-shaped groove to obtain a V-shaped copper-aluminum composite strip; (c13) In the step of twisting the copper strip, the copper strip (1) is twisted at an angle of 5° to 15°; (c14) The laminating and compounding step comprises laminating the copper strip (1) obtained by twisting the copper strip (c13) and the aluminum strip (2) obtained by grinding the aluminum strip (c11), laminating the copper strip composite surface and the aluminum strip composite surface obtained by grinding, interlocking the groove 1 (111) of the copper strip composite surface (11) and the groove 2 (221) of the aluminum strip composite surface (22), and cold rolling the copper strip (1) and the aluminum strip (2); In step (c13) of twisting the copper strip, a twisting device is used to twist the copper strip (1), the twisting device comprising a limit roller group 1 (4), a limit roller group 2 (5) and a twisting roller group (6), the limit roller group 1 (4) and the limit roller group 2 (5) are arranged horizontally along the conveying direction of the copper strip (1), the twisting roller group (6) is located between the limit roller group 1 (4) and the limit roller group 2 (5), the twisting roller group (6) comprises two twisting rollers (61) arranged parallel to each other, a twisting gap (62) is formed between the two twisting rollers (61) for the copper strip (1) to pass through; an inclination angle B is formed between the axis of the twisting roller (61) and the horizontal plane, and the copper strip (1) is input from the original horizontal direction to between the two twisting rollers (61) during the conveying process, and the copper strip (1) is tilted and twisted.

2. The photovoltaic V-shaped copper-aluminum composite strip production process according to claim 1, characterized in that: In step (a), a copper strip is rolled, and the copper strip has a thickness of 1 mm and a width of 6 mm. In step (b), an aluminum strip is rolled, and the aluminum strip has a thickness of 4 mm and a width of 6 mm.

3. The photovoltaic V-shaped copper-aluminum composite strip production process according to claim 1, characterized in that: (c1) After cold rolling and laminating, the thickness of the copper-aluminum composite strip is 1.25 mm; the cold rolling and laminating processing rate is greater than 70%, and the weight proportion of the copper strip in the copper-aluminum composite strip is 40% to 50%.

4. The photovoltaic V-shaped copper-aluminum composite strip production process according to claim 1, characterized in that: (c4) The continuous rolling step is that the continuous rolling passes are 2 to 5 times, and the rolling processing rate of each pass is 20% to 50%; (c4) After the continuous rolling, the thickness of the copper-aluminum composite strip is 0.35 mm.

5. The photovoltaic V-shaped copper-aluminum composite strip production process according to claim 1, characterized in that: (d) V-shaped surface forming includes the following steps: (d1) rolling forming, (d2) online annealing, (d3) drying, and (d4) winding; the step of (d1) rolling forming is to use a V-shaped surface forming roller group (3) to roll the (c) composite-formed copper-aluminum composite strip to form a V-shaped groove (211) on the surface of the aluminum strip (2) of the copper-aluminum composite strip to obtain a V-shaped copper-aluminum composite strip.

6. The photovoltaic V-shaped copper-aluminum composite strip production process according to claim 5, characterized in that: The height H of the V-shaped groove (211) is 0.037 mm±0.002 mm, and the angle of the V-shaped groove (211) is 117°±2°.

7. The photovoltaic V-shaped copper-aluminum composite strip production process according to claim 1, characterized in that: In the V-shaped copper-aluminum composite strip, a diffusion layer is formed at the bonding interface of the copper strip (1) and the aluminum strip (2), and the thickness of the diffusion layer is less than 3 μm.

8. A V-shaped copper-aluminum composite strip for photovoltaic use, characterized in that: The V-shaped copper-aluminum composite strip is produced by adopting the production process described in any one of claims 1 to 7.

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