Method of manufacturing a photovoltaic module and photovoltaic module

Abstract

The application relates to the photovoltaic technical field and discloses a photovoltaic module preparation method and a photovoltaic module. The photovoltaic module preparation method comprises the following steps: adopting a flattening device to flatten a solder strip located at a flattening position to form a flattened part, and cutting the solder strip with the flattened part, so that the solder strip after cutting forms a first soldering part and a second soldering part at two ends of the flattened part; welding the first soldering part with one of two adjacent cell pieces, welding the second soldering part with the other of the two adjacent cell pieces, and making the multiple cell pieces serially connected to form a cell string; and arranging encapsulating materials on two sides of the cell string to obtain the photovoltaic module; wherein the flattening device comprises a base for placing the solder strip and a pressing head which can move relative to the base to flatten the solder strip on the base. The photovoltaic module preparation method and the photovoltaic module provided by the application can be beneficial to avoiding the hidden crack damage phenomenon of the cell piece and improving the production yield of the photovoltaic module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a photovoltaic module preparation method and a photovoltaic module. BACKGROUND

[0002] With the continuous development of photovoltaic power generation technology, the installed capacity of photovoltaic modules is also increasing. Photovoltaic modules can generate electricity under the irradiation of sunlight, thereby realizing power generation. The cell pieces in the photovoltaic module have a photovoltaic effect and can convert solar energy into electrical energy for use by the load. The cell pieces usually go through multiple processes to obtain a formed photovoltaic module.

[0003] In the process of making a photovoltaic module, different cell pieces need to be electrically connected to form a cell string. In the process of connecting the cell pieces, the cell pieces may be abnormally cracked and damaged due to the state of the introduced connecting piece, resulting in a decrease in the production yield of the photovoltaic module. Therefore, how to avoid the cracking and damage of the cell pieces and improve the production yield of the photovoltaic module is an important problem. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a photovoltaic module preparation method and a photovoltaic module, which can help to avoid the cracking and damage of the cell pieces and improve the production yield of the photovoltaic module.

[0005] To solve the above technical problems, the embodiments of the present application provide a photovoltaic module preparation method. The photovoltaic module preparation method comprises: flattening a solder strip located at a flattening position by using a flattening device to form a flattened part, and cutting the solder strip with the flattened part, so that the solder strip after cutting forms a first soldering part and a second soldering part at both ends of the flattened part; welding the first soldering part with one of the two adjacent cell pieces, and welding the second soldering part with the other of the two adjacent cell pieces, so that the plurality of cell pieces are connected in series to form a cell string; and disposing encapsulating material on both sides of the cell string to obtain a photovoltaic module; wherein the flattening device comprises a base for placing the solder strip, and a pressing head movable relative to the base to flatten the solder strip located on the base, the pressing head can rotate around a preset direction when it separates from the solder strip after flattening the solder strip located at the flattening position, and the preset direction is perpendicular to the length direction of the solder strip.

[0006] The embodiments of the present application also provide a photovoltaic module, which is made by using the above photovoltaic module preparation method. The photovoltaic module comprises a cell string and encapsulating material located on both sides of the cell string, the cell string comprises a plurality of cell pieces and a solder strip connecting the plurality of cell pieces, and the solder strip comprises a first soldering part, a flattened part and a second soldering part arranged in sequence along the length direction, the first soldering part is connected with one of the two adjacent cell pieces, and the second soldering part is connected with the other of the two adjacent cell pieces.

[0007] The photovoltaic module manufacturing method and photovoltaic module provided by the embodiments of the present application use a flattening device to flatten the solder strip at the flattening position, so that the part of the solder strip at the flattening position forms a flattening part with a small thickness. After the solder strip with the flattening part is cut, the two ends of the flattening part form a first soldering part and a second soldering part, respectively. The first soldering part and the second soldering part are connected to different cell pieces to form a cell string, and the cell string is then encapsulated to form a photovoltaic module. When the pressure head of the flattening device is separated from the solder strip after flattening the part of the solder strip at the flattening position, the pressure head can rotate around a preset direction. This can avoid the solder strip from being tilted or deflected due to different rotating modes of the pressure head, and thus avoid the cell pieces from being cracked or broken when connected to the cell pieces, thereby improving the production yield of the photovoltaic module.

[0008] In some embodiments, the length of the flattening part is 6-20 mm.

[0009] In some embodiments, the base can rotate around the length direction of the solder strip when the pressure head flattens the solder strip at the flattening position.

[0010] In some embodiments, the pressure head includes a pressing surface and a giving surface connected to the pressing surface. The pressing surface is used to contact the solder strip at the flattening position to apply pressure to the solder strip. The giving surface is located on one side of the pressing surface in the length direction of the solder strip, and the giving surface and the pressing surface are located on different planes.

[0011] In some embodiments, the pressure head further includes a side surface perpendicular to the pressing surface, and the included angle between the giving surface and the side surface is 60-90°.

[0012] In some embodiments, the projection length of the giving surface in the length direction of the solder strip is 2-5 mm.

[0013] In some embodiments, before the solder strip at the flattening position is flattened by the flattening device to form the flattening part, the method further includes: clamping the head of the solder strip by a clamp and pulling the solder strip, so that the solder strip is pulled out from the winding state and passes through the flattening position; and arranging a weight on the moving path of the solder strip, so that the solder strip passes through the weight and the weight presses the solder strip.

[0014] In some embodiments, after the solder strip at the flattening position is flattened by the flattening device to form the flattening part, the method further includes: continuing to pull the solder strip by the clamp, so that the flattening part moves away from the base; clamping the flattening part; and releasing the clamp to clamp the head of the solder strip.

[0015] In some embodiments, after the solder strip at the flattening position is flattened by the flattening device to form the flattening part, the method further includes: detecting the state of the solder strip by a detection mechanism to determine whether the solder strip is tilted. BRIEF DESCRIPTION OF DRAWINGS

[0016] One or more embodiments are illustrated by way of example in the figures that are part of this document and which illustrate various embodiments of the application, and which are not intended to limit the scope of the application, the same being indicated by the same reference numbers in the figures of the accompanying drawings and where identical components have the same reference numbers unless otherwise indicated. The figures in the accompanying drawings are not intended to be to scale.

[0017] Figure 1 is a flow chart of a method for manufacturing a photovoltaic module according to some embodiments of the present application;

[0018] Figure 2 is a front view of a pressing head and a base when they are engaged according to some embodiments of the present application;

[0019] Figure 3 is a side view of a pressing head and a base when they are engaged according to some embodiments of the present application;

[0020] Figure 4 is a structure diagram of a cut-off solder ribbon according to some embodiments of the present application;

[0021] Figure 5 is a structure diagram of a connection of a cell according to some embodiments of the present application;

[0022] Figure 6 is a structure diagram of a cooperation of a solder ribbon and a cell according to some embodiments of the present application;

[0023] Figure 7 is a structure diagram of a photovoltaic module according to some embodiments of the present application.

[0024] Reference signs: 11, base; 101, second rotating shaft; 12, pressing head; 121, pressing surface; 122, giving place surface; 123, side surface; 102, first rotating shaft; 21, solder ribbon; 22, rolling part; 23, first soldering part; 24, second soldering part; 31, cell; 300, cell string; 400, adhesive film; 500, cover plate. DETAILED DESCRIPTION

[0025] In order to make the purposes, technical solutions, and advantages of the embodiments of the present application clearer, the various embodiments of the present application will be described in detail below with reference to the drawings. However, those skilled in the art can understand that, in the various embodiments of the present application, many technical details are presented in order to make the readers better understand the present application. However, the technical solutions claimed by the present application can be implemented even without these technical details and various changes and modifications based on the following various embodiments. The division of the following various embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the present application. The various embodiments can be combined and referenced to each other without contradiction.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application; the use of the terms "including," "comprising," "having" and variations thereof in the specification and claims and the aforementioned summary of the application are intended to cover both the inclusive and exclusive cases.

[0027] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection" and other terms should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0028] With the increase of the installed capacity of photovoltaic modules, it is also important to improve the production yield of photovoltaic modules. In the manufacturing process of photovoltaic modules, different processes will affect the production yield of photovoltaic modules, therefore, it is important to ensure the normal operation of different processes to improve the production yield of photovoltaic modules, especially to ensure the normal operation of the string welding process. The string welding process connects the cell pieces together through the connecting piece to form a cell string, and the connecting piece usually adopts a welding strip. Before connecting the cell pieces, the welding strip is subjected to calendering treatment, so that part of the position of the welding strip is flattened, the part of the welding strip that is flattened is thinner, can be the part that bends between two adjacent cell pieces, can be elastically deformed, reduces the pressure formed on the cell piece when the welding strip is welded, and in turn reduces the phenomenon of hidden crack damage of the cell piece, that is, ensures that the cell piece will not appear stress concentration phenomenon due to the welding strip being too high after string welding, and in turn avoids the hidden crack damage phenomenon of the cell piece. However, the cell piece will be turned on its side when subjected to calendering treatment, so that when the welding strip is matched with the cell piece, the wider part formed after calendering is between two cell pieces, and the risk of hidden crack damage of the cell piece cannot be reduced.

[0029] Currently, in the flattening device, the pressure head presses two solder strips at one time. In order to ensure the uniformity of the calendered thickness of the two solder strips, a balance shaft is added at the center position of the pressure head, so that the pressure head can rotate around the length direction of the solder strip, and self-adaptation compression is realized in the flattening process. It is found in actual test that the reason why the solder strip will be turned over during the calendering process is that the free rotation of the pressure head around the length direction of the solder strip will cause the left and right swing phenomenon during the separation from the solder strip, and after the pressure head is pressed down, the flattened part of the solder strip is tightly attached to the surface of the pressure head, and the left and right swing during the separation of the pressure head and the solder strip will deviate the solder strip, so that the solder strip is turned over. Therefore, it is necessary to reduce the lateral force of the solder strip during the flattening process (calendering) of the solder strip, change the separation mode of the pressure head, reduce the probability of solder strip calendering turn over, reduce the fragment rate of the battery sheet, and thus improve the production yield of the overall photovoltaic module.

[0030] In order to reduce the left and right action of the solder strip, thereby reducing the probability of solder strip calendering turn over and ensuring the welding yield, some embodiments of the present application provide a photovoltaic module preparation method. When the photovoltaic module is manufactured, the rotation direction of the pressure head in the flattening device is changed, the pressure head is gradually separated in the length direction of the solder strip, and the solder strip is prevented from being turned over or deviated due to the left and right swing of the pressure head. Then, when the flattened and cut solder strip is laid on the battery sheet, it can be ensured that the thinner part formed after the calendering is located at the position where the two battery sheets are close to each other, the head and tail point height of the battery sheet is reduced, the virtual welding of the head and tail point of the battery sheet is reduced, the phenomenon of hidden crack damage of the battery sheet caused by the solder strip being too high is avoided, and the production yield of the photovoltaic module is improved.

[0031] The photovoltaic module preparation method provided by some embodiments of the present application will be described below in combination with Figure 1 In the photovoltaic module preparation method provided by some embodiments of the present application, Figure 2 and Figure 3 The cooperation structure of the pressure head and the base used in the photovoltaic module preparation method is shown, Figure 4 The structure of the solder strip after cutting in the photovoltaic module preparation method is shown, Figure 5 and Figure 6 The cooperation structure when the solder strip connects different battery sheets is shown, Figure 7 The structure of the obtained photovoltaic module is shown.

[0032] As Figure 1 shown, the photovoltaic module preparation method provided by some embodiments of the present application includes the following steps:

[0033] Step S110, using a flattening device to flatten the solder strip at the calendering position to form a calendering part, and cutting the solder strip with the calendering part to form a first welding part and a second welding part at both ends of the calendering part.

[0034] Before the string welding, the welding strip 21 is pre-processed by calendering, i.e. the welding strip 21 is flattened by a flattening device, and the flattening position of the welding strip 21 is at the middle position of the cutting and segmenting. After the flattening, the welding strip 21 forms a relatively thin calendering part 22, and the two sides of the calendering part 22 form relatively thick first and second welding parts 23 and 24 respectively. The first and second welding parts 23 and 24 are used to form connections with different battery pieces 31, and the first and second welding parts 23 and 24 have lengths close to or consistent with the battery pieces 31. The calendering part 22 is located at the position where the adjacent two battery pieces 31 are close to each other during the welding process.

[0035] As shown in Figure 2 and Figure 3 , the flattening device includes a base 11 for placing the welding strip 21, and a press head 12 movable relative to the base 11 to flatten the welding strip 21 located on the base 11. The press head 12 can rotate around a preset direction when it separates from the welding strip 21 after completing the flattening of the welding strip 21 located at the calendering position, and the preset direction is perpendicular to the length direction of the welding strip 21.

[0036] The press head 12 of the flattening device can cooperate with the base 11 to flatten the part of the welding strip 21 located at the calendering position, so that the thickness of the part of the welding strip 21 located at the calendering position in the moving direction of the press head 12 is reduced, forming the calendering part 22. The press head 12 can be installed through a first rotating shaft 102, so as to rotate relative to the front end power transmission support rod and swing in the length direction of the welding strip 21 by a certain amplitude. The center axis direction of the first rotating shaft 102 is perpendicular to the length direction of the welding strip 21 located at the calendering position.

[0037] In actual cases, the flattening device can further include a transmission mechanism and a power mechanism. The power mechanism outputs power, and the transmission mechanism transmits the power output by the power mechanism to the pressing head 12 to realize the pressing and retraction of the pressing head 12. The transmission mechanism can adopt a connecting rod mechanism to transmit the power output by the power mechanism to the pressing head 12 in a suitable form. Part of the solder strip 21 can be placed on the bearing surface of the base 11. The side of the pressing head 12 facing the base 11 has a pressing surface. When the pressing head 12 moves towards the base 11 until it is close to the base 11, the pressing surface of the pressing head 12 will apply pressure to the part of the solder strip 21 at the flattening position, forcing the part of the solder strip 21 at the flattening position to deform. The pressing head 12 can rotate around a predetermined direction during the flattening of the solder strip 21. The predetermined direction is perpendicular to the length direction of the solder strip 21, which refers to the length direction of the part of the solder strip 21 at the flattening position, i.e., the pressing head 12 can rotate around the width direction of the solder strip 21, i.e., swing forward and backward relative to the solder strip 21. When the pressing head 12 moves towards the solder strip 21 on the base 11 to flatten the solder strip 21, the pressing head 12 will first contact the solder strip 21 and apply pressure to the solder strip 21 through the power provided by the front end, forcing the part of the solder strip 21 at the flattening position to deform. During this process, the pressing head 12 will embed in the deformed part of the solder strip 21 and form a close contact with the deformed part of the solder strip 21. At this time, when the driving pressing head 12 is separated from the solder strip 21, the movement of the pressing head 12 will affect the state of the solder strip 21. When the pressing head 12 swings left and right, the solder strip 21 will be tilted or deflected due to the difference in the order of separation of the pressing head 12 in the width direction of the solder strip 21. By changing the left-right swinging of the pressing head 12 to forward-backward swinging, the pressing head 12 will only have a difference in the order of separation in the length direction of the solder strip 21, which will not cause the solder strip 21 to tilt or deflect. Moreover, the forward-backward swinging of the pressing head 12 when separating from the solder strip 21 can make the pressing head 12 sequentially separate from the flattened part 22 formed on the solder strip 21 in the length direction of the solder strip 21, ensuring smooth separation.

[0038] In addition, the pressing head 12 can also rotate in multiple different directions, i.e., have multiple degrees of freedom, and adaptively deflect in multiple directions. The angle of rotation can be any angle within 5°.

[0039] In step S120, the first welding part is welded with one of the two adjacent battery pieces, and the second welding part is welded with the other of the two adjacent battery pieces, so that the plurality of battery pieces are connected in series to form a battery string.

[0040] Figure 4The cut and segmented solder strip 21 can be connected with the battery sheet 31, and different welding portions of the solder strip 21 are welded with different battery sheets 31 respectively, so that the plurality of battery sheets 31 are connected in series to form a battery string 300. When the different welding portions of the solder strip 21 are connected with the battery sheet 31, the different welding portions are welded on different surfaces of two battery sheets 31, so that the positive and negative electrodes of the adjacent two battery sheets 31 are connected. As shown in Figure 5 and Figure 6 The first welding portion 23 can be welded on the front surface of one battery sheet 31 to form an electrical connection with the front surface main grid, and the second welding portion 24 can be welded on the back surface of another battery sheet 31 to form an electrical connection with the back surface main grid.

[0041] In actual cases, one of the first welding portion 23 and the second welding portion 24 can be connected with the battery sheet 31 first, and then the plurality of battery sheets 31 welded with one of the welding portions of the solder strip 21 are arranged in sequence, and then the other welding portion is connected with the other battery sheet 31.

[0042] In step S130, the encapsulating material is arranged on both sides of the battery string to obtain a photovoltaic module.

[0043] After the battery sheets 31 are connected in series, the encapsulating material can be arranged on the two side surfaces of the battery string 300 respectively, and the battery string 300 is encapsulated inside by the encapsulating material to protect the battery sheets 31. The two sides of the battery string 300 are the front surface side and the back surface side with larger areas respectively.

[0044] In actual cases, after the battery string 300 is formed, the battery string 300 can be laminated and packaged, and packaging materials are arranged on both sides of the battery string 300, including the adhesive film 400 and the cover plate 500, and the cover plate 500 is bonded to the battery string 300 through the adhesive film 400. The adhesive film 400 can be a packaging adhesive film such as a polyvinyl butyral (PVB) adhesive film, an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene copolymer elastomer (POE) adhesive film, or a polyethylene terephthalate (PET) adhesive film. Alternatively, the adhesive film 400 can be an EP adhesive film, an EPE adhesive film, or a PVP adhesive film. The cover plate 500 can be a glass cover plate or a plastic cover plate. During the packaging process, a front adhesive film and a front cover plate are arranged on the front side of the battery string 300, and a back adhesive film and a back cover plate are arranged on the back side of the battery string 300. After the battery string 300 is laminated with the packaging materials, the front adhesive film and the back adhesive film are fused to wrap the battery string inside, the front cover plate is bonded to the front side of the battery string 300 through the front adhesive film, and the back cover plate is bonded to the back side of the battery string 300 through the back adhesive film. The cover plate 500 and the adhesive film 400 can both allow light to pass through, so that the battery piece 31 wrapped inside can receive light irradiation and generate current.

[0045] The photovoltaic module preparation method provided by some embodiments of the present application uses a flattening device to flatten the solder strip 21 located at the stretching position, so that the part of the solder strip 21 located at the stretching position forms a stretching part 22 with a small thickness. After the solder strip 21 with the stretching part 22 is cut, the two ends of the stretching part 22 form a first soldering part 23 and a second soldering part 24, respectively. The first soldering part 23 and the second soldering part 24 are connected to different battery pieces 31 to form a battery string 300, and then the battery string 300 is packaged to form a photovoltaic module. When the pressure head 12 of the flattening device separates from the solder strip 21 after flattening the part of the solder strip 21 located at the stretching position, the pressure head 12 can rotate around a preset direction. This can avoid the solder strip 21 from tilting or deflecting due to different rotation modes of the pressure head 12, and thus avoid the phenomenon of hidden cracks and breakage of the battery piece 31 when connecting to the battery piece 31, thereby improving the production yield of the photovoltaic module.

[0046] In actual cases, for the flattening device, a shaft can be used to install the pressure head 12, so that the pressure head 12 can rotate around the axial direction of the shaft. The axial direction of the shaft is perpendicular to the length direction of the solder strip 21 located at the stretching position.

[0047] In some embodiments, the length of the stretching part 22 can be 6-20 mm.

[0048] The calendering portion 22 is located at the position where the two adjacent battery pieces 31 are close to each other when the welding strip 21 is connected to the two battery pieces 31. By controlling the length of the calendering portion 22, it can be avoided that the calendering portion 22 is too short to play a good transition role, or the gap between the battery pieces 31 is too large due to the calendering portion 22 being too long, thereby avoiding affecting the light receiving area of the photovoltaic module. In actual cases, the length of the calendering portion 22 can be 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm or 20 mm.

[0049] In some embodiments, the base 11 can rotate around the length direction of the welding strip 21 when the pressing head 12 is flattening the welding strip 21 located at the calendering position.

[0050] That is, after canceling the adaptive rotation of the pressing head 12 around the length direction of the welding strip 21, the adaptive rotation of the base 11 around the length direction of the welding strip 21 can be introduced. By making the base 11 rotatable around the length direction of the welding strip 21, the pressing head 12 can ensure the close effect when pressing down by using the left and right rotation of the base 11 when flattening the welding strip 21, thereby ensuring the thickness consistency of the calendering portion 22 of the welding strip 21. If the pressing head 12 and the base 11 are not close, the base 11 will rotate at a certain angle, for example, 3°, 4° or 5°, and finally the pressing head 12 and the base 11 are completely close, ensuring the flattening effect of the welding strip 21. As shown in Figure 3 The base 11 can be installed through the second rotating shaft 101 and cooperates with the base part of the flattening device, so that the base 11 can swing in the width direction of the welding strip 21 within a certain amplitude. The central axis direction of the second rotating shaft 101 is parallel to the length direction of the welding strip 21 located at the calendering position.

[0051] As shown in Figure 2 The pressing head 12 can include a pressing surface 121 and a giving surface 122 connected to the pressing surface 121. The pressing surface 121 is used to contact the welding strip 21 located at the calendering position to apply pressure to the welding strip 21. The giving surface 122 is located on one side of the pressing surface 121 in the length direction of the welding strip 21. The giving surface 122 and the pressing surface 121 are located on different planes.

[0052] The pressure surface 121 and the displacement surface 122 are located on the side of the pressure head 12 close to the base 11. The two sides of the pressure surface 121 are provided with the displacement surface 122. The pressure surface 121 is in contact with the solder strip 21, thereby completing the flattening process of the solder strip 21. The displacement surface 122 is adjacent to the pressure surface 121. The displacement surface 122 corresponds to the end of the part of the solder strip 21 located in the calendering position. The displacement surface 122 can exert a smaller pressure on one side of the pressure surface 121 to form a transition part with varying thickness at one end of the calendering part 22 of the solder strip 21. The displacement surface 122 can be inclined relative to the pressure surface 121, or parallel to the pressure surface 121 and spaced from the pressure surface 121.

[0053] The transition part with varying thickness formed by the displacement surface 122 when pressed can make the resistance of the pressure head 12 to the solder strip 21 smaller when separated, facilitating the retraction of the pressure head 12 after completing the pressing action. In addition, the displacement surface 122 can avoid the phenomenon that the ends of the flattened part of the solder strip 21 are raised when the pressure head 12 applies pressure to the part of the solder strip 21 located in the calendering position, thereby avoiding the solder strip 21 being clamped on the bottom side of the pressure head 12, avoiding affecting the separation of the pressure head 12, and ensuring the flatness of the solder strip 21.

[0054] In addition, the pressure head 12 can further include a side surface 123 perpendicular to the pressure surface 121. The included angle between the displacement surface 122 and the side surface 123 is 60° to 90°.

[0055] The side surface 123 is perpendicular to the pressure surface 121. The displacement surface 122 is arranged in an inclined state. The displacement surface 122 forms an obtuse angle with the pressure surface 121, or the displacement surface 122 is parallel to the pressure surface 121, which can ensure that the displacement surface 122 is relatively gentle relative to the pressure surface 121. By controlling the angle between the displacement surface 122 and the side surface 123 of the pressure head 12, it can be avoided that the displacement surface 122 cannot play a displacement role due to the small included angle between the displacement surface 122 and the side surface 123, or that part of the displacement surface 122 cannot be closely attached to the solder strip 21 due to the large included angle between the displacement surface 122 and the side surface 123, thereby avoiding affecting the integrity of the transition part formed at one end of the calendering part 22 of the solder strip 21. In actual situations, the included angle between the displacement surface 122 and the side surface 123 can be 60°, 65°, 70°, 75°, 80°, 85°, or 90°.

[0056] In some embodiments, the projection length of the displacement surface 122 in the length direction of the solder strip 21 can be 2 mm to 5 mm.

[0057] By controlling the projection length of the displacement surface 122 in the length direction of the solder strip 21, the length of the end of the calendered portion 22 of the solder strip 21 can be controlled when the displacement surface 122 is used to press down the solder strip 21. When the displacement surface 122 is arranged obliquely relative to the pressing surface 121, the length of the displacement surface 122 in the horizontal direction can be 2-5 mm, for example, 2 mm, 3 mm, 4 mm or 5 mm.

[0058] In actual cases, the pressing surface 121 can be polished or plated with chromium.

[0059] By polishing or plating the pressing surface 121 with chromium, the smoothness of the pressing surface 121 can be improved, thereby reducing the close contact between the pressing surface 121 and the solder strip 21 after the solder strip 21 is flattened at the calendered position, reducing the degree of embedding of the solder strip 21 into the pressing surface 121, and reducing the solder strip 21 adhesion, thereby reducing the driving effect of the solder strip 21 when the pressure head 12 is separated from the solder strip 21.

[0060] In addition, a microstructure can be formed on the bottom of the pressure head 12 using a surface micro-texture technology, and a microstructure with a pit diameter of 50-200 microns can be prepared on the surface of the pressure head 12 by laser or electrolytic processing, which can also reduce the solder strip 21 adhesion. In actual cases, the pit diameter of the microstructure formed on the surface of the pressure head 12 can be 50 microns, 100 microns, 150 microns or 200 microns.

[0061] In some embodiments, the photovoltaic module preparation method can further include the following steps:

[0062] When the pressure head 12 moves away from the base 11 and is separated from the solder strip 21, vibration is applied to the pressing surface 121.

[0063] By applying vibration to the pressing surface 121, the adhesion between the pressure head 12 and the solder strip 21 can be effectively prevented, which is beneficial to avoiding a large driving effect on the solder strip 21 when the pressure head 12 is separated from the solder strip 21.

[0064] In actual cases, a piezoelectric ceramic module can be installed inside the pressure head 12, and high-frequency vibration can be applied to the pressure head 12 and the solder strip 21 by the piezoelectric ceramic module when the pressure head 12 is separated from the solder strip 21, and the frequency of the vibration can be 20-40 kHz, which can reduce the rebound deflection of the solder strip 21.

[0065] In addition, before the solder strip at the calendered position is flattened by the flattening device in step S110, the following steps can also be included:

[0066] Step S101: The head of the solder strip is clamped by the chuck, and the solder strip is pulled out from the winding state and passes through the calendered position.

[0067] The clamp head, as a clamping device, can clamp the head of the welding strip 21 and move the welding strip 21 by moving the clamp head, so that the welding strip 21 is pulled out from the winding state and a part of the welding strip 21 pulled out is in a flat state. That is, the clamp head can play a role of pulling and straightening and move the welding strip 21, so that the welding strip 21 continuously undergoes the flattening and cutting process.

[0068] In step S102, a weight is arranged on the movement path of the welding strip, so that the welding strip passes through the weight and the weight presses the welding strip.

[0069] The weight is located on the movement path of the welding strip 21, and the straightened welding strip 21 can be pressed by the weight, so that the straightened welding strip 21 enters a tension state from a relatively relaxed state. After being tensioned, the straightened welding strip 21 can ensure the flatness of the welding strip 21, so that the part of the welding strip 21 located at the flattening position does not appear to be bent.

[0070] In some embodiments, after the welding strip at the flattening position is flattened by the flattening device in step S110 to form the flattened part, the following steps can be further included:

[0071] In step S111, the welding strip is continuously pulled by the clamp head, and the flattened part is moved away from the base.

[0072] After the flattening action is completed, subsequent cutting and transferring can be performed, so that the welding strip 21 can be pulled again by the clamp head, so that the flattened and formed flattened part 22 can move away from the flattening position, that is, move away from the base 11, to prepare for subsequent cutting.

[0073] In step S112, the flattened part is clamped.

[0074] After the flattened part 22 moves away from the base 11, the flattened part 22 can be clamped, so that the welding strip 21 can be kept in a fixed state.

[0075] In step S113, the clamp head clamping the head of the welding strip is released.

[0076] After the flattened part 22 of the welding strip 21 is fixed, the clamp head clamping the head of the welding strip 21 can be released, so that the welding strip 21 can release the stress formed after the flattening process, so that the welding strip 21 can recover from the slightly deflected state to the flat state when straightened, and then ensure the posture of the welding strip 21. In the posture that the welding strip 21 keeps the flattened part 22 flat, the welding strip 21 can be transferred to a welding station, so that the welding part of the welding strip 21 cooperates with the battery piece 31 to complete the positioning and welding process.

[0077] In some embodiments, after the welding strip at the flattening position is flattened by the flattening device in step S110 to form the flattened part, the following steps can be further included:

[0078] Step S114, detecting the state of the solder strip by the detection mechanism to determine whether the solder strip is side flipped.

[0079] In actual situation, a CCD (Charge-Coupled Device) camera can be added on the moving path of the solder strip 21 to detect the thickness and surface defects of the solder strip 21 after the flattening process in real time.

[0080] The detection camera after the welding of the battery piece 31 can add feature point recognition to determine the calendered width. The normal calendered width of the solder strip 21 is about 0.3 mm, while the calendered width after the side flipping is between 0.1 mm and 0.25 mm. The recognition detection of the calendered width can ensure that the solder strip 21 with abnormal state is accurately recognized and the manual intervention is facilitated to ensure the overall production yield of the assembly. The detection mechanism can detect without stopping, and the feature recognition can be directly performed during the welding process to determine whether the calendered part 22 of the solder strip 21 has the side flipping phenomenon.

[0081] Generally, the solder strip 21 soaked with the flux is laid on the calendering mechanism, and the pressure head 12 is driven by the lever principle to flatten the solder strip 21. To ensure the uniformity of the calendered thickness of the solder strip 21 on both sides of the pressure head 12, a rotating shaft is usually installed at the center position of the pressure head 12. Due to the existence of the rotating shaft, the pressure head 12 will swing left and right during the lifting process, thereby deviating the solder strip 21 and causing the side flipping phenomenon. By changing the movement form of the pressure head 12, the probability of the solder strip 21 side flipping can be reduced, and by setting the movement form of the base 11, the calendering effect of the solder strip 21 can be ensured. After the welding, the solder strip 21 with the side flipping problem can be controlled in the current process to prevent the abnormal products from flowing out and ensure the production yield.

[0082] The flattening device can be mounted at the solder strip 21 arrangement stage of the stringer, and the part of the solder strip 21 at the calendering position is flattened during the pulling process of the solder strip 21. On the one hand, the soldering overhead ratio is reduced to reduce the false welding, and on the other hand, the laminated cracking phenomenon caused by the side flipping of the solder strip 21 is reduced to improve the production yield of the assembly.

[0083] Before the string welding process, the battery piece 31 is provided, which can be subjected to the slicing and drying, sprayed with the flux, and then positioned and grabbed to the string welding station. The solder strip 21 can be flattened and cut after being soaked with the flux, matched with the battery piece 31, and fixed between the solder strip 21 and the battery piece 31 by welding to form the battery string 300, which can be subjected to the defect test by performing the EL (Electro Luminescent) detection.

[0084] By setting the moving form of the pressure head 12 when it is separated from the solder strip 21, i.e., separated from the solder strip 21, the adverse effect on the posture of the solder strip 21 can be avoided, and the solder strip 21 after the flattening treatment can be prevented from being turned over or turned upside down, thereby improving the production yield of the photovoltaic module.

[0085] Some embodiments of the present application also provide a photovoltaic module prepared by the above photovoltaic module preparation method. As shown in Figure 7 The photovoltaic module includes a cell string 300 and encapsulating materials on both sides of the cell string 300. The cell string 300 includes a plurality of cell pieces 31 and a solder strip 21 connecting the plurality of cell pieces 31. The solder strip 21 includes a first soldering portion 23, a flattened portion 22, and a second soldering portion 24 arranged in sequence along the length direction. The first soldering portion 23 is connected to one of the adjacent two cell pieces 31, and the second soldering portion 24 is connected to the other of the adjacent two cell pieces 31.

[0086] The plurality of cell pieces 31 are connected in series by using the solder strip 21. The cut and segmented solder strip 21 can be connected to the cell pieces 31. Different soldering portions of the solder strip 21 are respectively soldered to different cell pieces 31, so that the plurality of cell pieces 31 are connected in series to form the cell string 300. When the different soldering portions of the solder strip 21 are connected to the cell pieces 31, the different soldering portions are soldered to different surfaces of the two cell pieces 31, so that the anode and the cathode of the adjacent two cell pieces 31 are connected. For example, the first soldering portion 23 can be soldered to the front surface of one cell piece 31 to form an electrical connection with the front surface busbar, and the second soldering portion 24 can be soldered to the back surface of another cell piece 31 to form an electrical connection with the back surface busbar. The solder strip 21 can realize the connection between the adjacent two cell pieces 31. The cell pieces 31 can be close to each other at the edges and be overlapped or inclined at an angle, i.e., the front and back surfaces of the cell pieces 31 can be parallel to the front and back surfaces of the cover plate 500, or form a certain angle. The edges of the adjacent two cell pieces 31 can be overlapped to arrange more cell pieces 31, or the edges of the adjacent two cell pieces 31 can be separated from each other to avoid shading. By flattening the solder strip 21 to form the flattened portion 22, the thickness of the solder strip 21 can be reduced, so that the overlapping height between the adjacent two cell pieces 31 is reduced, and the large force on the cell pieces 31 caused by the high solder strip 21 is avoided, thereby avoiding the hidden cracking and damage of the cell pieces 31.

[0087] In addition, the surface of the calendered portion 22 of the welding strip 21 can be kept parallel to the surface of the battery piece 31, and when the calendered portion 22 of the welding strip 21 is longer, the calendered portion 22 can be formed with a certain degree of bending to better transition. The distance between the calendered portion 22 of the welding strip 21 and the end point of the surface of the battery piece 31 can be controlled to about 1.5 mm, such as 1 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm, or 2 mm.

[0088] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application.

Claims

1. A method for manufacturing a photovoltaic module, characterized in that, The application relates to a method for manufacturing a photovoltaic module. The method comprises the following steps: a flattening device is used to flatten a solder strip at a flattening position to form a flattened part, and the solder strip with the flattened part is cut to form a first soldering part and a second soldering part at two ends of the flattened part; one of the first soldering part and the second soldering part is soldered to one of two adjacent battery pieces, and the other of the first soldering part and the second soldering part is soldered to the other of the two adjacent battery pieces, so that a plurality of battery pieces are connected in series to form a battery string; encapsulation materials are arranged on both sides of the battery string to obtain the photovoltaic module.

2. The photovoltaic module production method according to claim 1, wherein The flattening device comprises a base for placing the solder strip and a pressing head which can move relative to the base to flatten the solder strip on the base, and the pressing head can rotate around a preset direction when the pressing head is separated from the solder strip after flattening the solder strip at the flattening position, and the preset direction is perpendicular to the length direction of the solder strip.

3. The photovoltaic module production method according to claim 1, wherein The length of the flattened part is 6-20 mm.

4. The photovoltaic module production method according to claim 1, wherein The base can rotate around the length direction of the solder strip when the pressing head flattens the solder strip at the flattening position.

5. The photovoltaic module production method according to claim 4, wherein The pressing head comprises a pressing surface and a displacement surface which is connected to the pressing surface, the pressing surface is used to contact the solder strip at the flattening position to apply pressure to the solder strip, the displacement surface is located on one side of the pressing surface in the length direction of the solder strip, and the displacement surface is located on a different plane from the pressing surface.

6. The photovoltaic module production method according to claim 5, wherein The pressing head further comprises a side surface which is perpendicular to the pressing surface, and the included angle between the displacement surface and the side surface is 60-90 degrees.

7. The photovoltaic module production method according to claim 1, wherein The projection length of the displacement surface in the length direction of the solder strip is 2-5 mm. Before the flattening device is used to flatten the solder strip at the flattening position to form the flattened part, the method further comprises the following steps: a chuck is used to clamp the head of the solder strip, and the solder strip is pulled out from the winding state and passes through the flattening position; 8. The photovoltaic module production method according to claim 7, wherein a heavy hammer is arranged on the moving path of the solder strip, the solder strip passes through the heavy hammer, and the heavy hammer presses the solder strip. After the flattening device is used to flatten the solder strip at the flattening position to form the flattened part, the method further comprises the following steps: the chuck continues to pull the solder strip, and the flattened part leaves the base; the flattened part is clamped; 9. The photovoltaic module production method of claim 1, wherein the chuck is loosened to clamp the head of the solder strip. After the flattening device is used to flatten the solder strip at the flattening position to form the flattened part, the method further comprises the following steps:

10. A photovoltaic module made by the method of any one of claims 1 to 9, characterized in that, a detection mechanism is used to detect the state of the solder strip to determine whether the solder strip is turned over. The photovoltaic module comprises a battery string and encapsulation materials arranged on both sides of the battery string, the battery string comprises a plurality of battery pieces and a solder strip connecting the plurality of battery pieces, the solder strip comprises a first soldering part, a flattened part and a second soldering part arranged in sequence in the length direction, the first soldering part is connected to one of two adjacent battery pieces, and the second soldering part is connected to the other of the two adjacent battery pieces.

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