A solar cell string, its preparation method and application

Abstract

The present invention provides a solar cell string, a preparation method thereof and an application. The solar cell string includes solar cell wafers and solder tapes for connecting the solar cell wafers in series. The solder tapes are bonded to the surfaces of the solar cell wafers through double-sided transparent tapes. The double-sided transparent tapes are located between the solder tapes and the solar cell wafers. At the positions on the solar cell wafers where the double-sided transparent tapes are placed, short grid lines in a direction different from that of the sub-grid lines are provided. The preparation method of the solar cell string provided by the present invention can easily bond the solder tapes to the solar cell wafers, replacing the original welding pad points, reducing the amount of silver paste used and the shading loss at the same time, and can be obtained by changing some accessories on the current welding machine; the transmittance of the tape is greater than 50%, which does not affect the sunlight from entering the area under the tape. The function of the short horizontal line is to lead the photocurrent generated in the area under the tape to the adjacent grid line, and it is not necessary to first combine the tape with the solder tape, greatly simplifying the preparation process.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and relates to a solar cell string, a preparation method and an application thereof, and particularly relates to a main-grid-free solar cell string, a preparation method and an application thereof. Background Art

[0002] In the field of main-grid-free solar cells, when using only fine grid lines for current collection, problems such as an increase in series resistance and a decrease in fill factor will occur, resulting in a serious reduction in the power of the manufactured components; screen-printing relatively wide silver paste grid lines to reduce the series resistance, but due to the increase in the amount of silver used, it will bring a sharp rise in cost. At the same time, the wide grid lines will also cause a deterioration in the insulation effect between P-N and an easy leakage problem.

[0003] In the solar cell industry, several single-crystalline silicon cells need to be connected together in series by soldering tapes to facilitate the extraction of the current generated by all the silicon cells. The connection method of the soldering tape is to weld one end to the front main grid of the front-side silicon cell and the other end to the back main grid of the back-side silicon cell. At present, the thickness of silicon cells shows a trend of becoming thinner. Using the connection method of soldering tapes is more likely to cause hidden cracks. In this way, the connection method of soldering tapes will be more and more restricted.

[0004] When a solar cell string is formed by connecting solar cells in series with a strip-shaped soldering tape, since outside the tape (or called a strip-shaped adhesive film) area, the soldering tape is directly in contact with EVA, during lamination, EVA (Ethylene Vinyl Acetate Copolymer) melts and has fluidity, and there may be a situation where EVA insulates the soldering tape and the fine grid during lamination.

[0005] To improve the application of screen-printed main grid lines, the best way is to completely avoid the main grid lines. However, the technical difficulty in completely avoiding the main grid lines lies in how to connect the batteries in series. At present, there is also an existing technology that provides a polymer adhesive film. The adhesive film is first bonded to a wire, then placed on the battery, and finally laminated together. This technology can completely avoid the use of main grid lines, but the adhesive film requires a special structure and needs to be bonded to the wire and then fixed to the battery, increasing the process complexity.

[0006] CN100431175A discloses an electrode, which includes a flat surface transparent electrically insulating optical film. An adhesive is coated on the flat surface, and then parallel wires are embedded in the adhesive layer. The thickness of the adhesive is less than the thickness of the wires, so that the protruding part forms an ohmic contact with the optoelectronic element.

[0007] CN108419433A discloses a polymer conductor plate, a solar cell and a production method thereof. In a homogeneous polymer plate, two-layer or three-layer regions are formed by means of heat, radiation, chemistry, etc. The first region has a low crosslinking degree or polymerization degree and is thermally adherent. The second region has a high crosslinking degree or polymerization degree and is a support layer. The third layer has an even lower crosslinking degree or polymerization degree. Multiple groups of parallel wires are adhered to the first region to form a polymer plate, and then a battery string is formed.

[0008] Both of the above two documents mention the curing of a transparent adhesive film, a polymer plate or a liquid adhesive. As a person skilled in the art, these three names all refer to a polymer adhesive film. The adhesive film is bonded to the wire, and then welding is achieved during lamination to achieve electrical contact. However, all three methods must additionally add a processing platform for polymer adhesive film materials, a bonding platform for adhesive film materials and wires, etc., which undoubtedly increases the cost and complexity. In addition, the adhesive film, i.e., the bonding layer, provided by these three methods is on the layer of the metal wire away from the solar cell and adopts full coverage, so high requirements are imposed on its light transmittance and stability.

[0009] Therefore, how to adjust the connection mode of the solder ribbon while avoiding light shielding of the main grid line of the solar cell and large consumption of silver is a technical problem to be solved urgently. Summary of the Invention

[0010] The purpose of the present invention is to provide a solar cell string, a preparation method and an application thereof. The present invention connects the solder ribbon and the solar cell chip through a double-sided transparent adhesive tape, and with a special grid line design, the solder ribbon can be easily adhered to the solar cell chip, replacing the original welding pad points (metal solder joints) to form a solar cell string, reducing the amount of silver paste used and reducing the light shielding loss at the same time, and can be obtained by changing some accessories on the current welding machine. The method is simple and convenient; the adhesive tape is located between the solder ribbon and the battery, which will not affect the extraction of the photocurrent of the solar cell chip under the adhesive tape, and there is no need to combine the adhesive tape with the solder ribbon first, greatly simplifying the preparation process.

[0011] To achieve the purpose of this invention, the following technical solutions are adopted by the present invention:

[0012] In the first aspect, the present invention provides a solar cell string, which includes solar cell chips and solder ribbons that connect the solar cell chips in series. The solder ribbons are bonded to the surfaces of the solar cell chips through double-sided transparent adhesive tapes. The double-sided transparent adhesive tapes are located between the solder ribbons and the solar cell chips. Short grid lines in a direction different from that of the sub-grid lines are provided at the positions of the solar cell chips where the double-sided transparent adhesive tapes are placed.

[0013] The solar cell string provided by the present invention refers to a component structure formed by connecting multiple groups of solar cells in series through solder tapes, with the head and tail connected in series. The connection method is that the positive electrode of the previous solar cell is connected to the negative electrode of the next solar cell, that is, an alternating positive and negative connection. The provided solder tape is the wire for connecting between solar cells. The solder tape is a segmented solder tape, and its length is greater than or equal to 2 times the length of the connected solar cell. One side of the solder tape is in close contact with the front side of one solar cell, and the other side forms contact with the back side of the adjacent solar cell. Connecting them in sequence can form a solar cell string.

[0014] In the present invention, the strip-shaped tape cannot affect the light absorption of the solar cell, so it should have the characteristic of transparency. At the same time, there is no specific requirement for the conductivity of the tape. It can be a conductive tape or a non-conductive tape.

[0015] In a solar cell, the grid lines are the electrodes, and their function is to conduct the current generated by the solar cell. Generally, the grid lines (electrodes) of the solar cell are formed by screen printing and then sintering, and are composed of many single lines that are parallel to each other and have the same spacing. The battery string provided by the present invention is a main-gridless battery string, that is, there are only sub-grid lines and no main grid lines.

[0016] In the present invention, when the double-sided transparent tape is located between the solar cell and the solder tape, for the grid lines under the solder tape, due to the insertion of the tape in the middle, the grid lines will be insulated from the solder tape (wire), resulting in the inability to conduct the current generated in the area under the tape. By matching with special short grid lines, the design of multiple single grid lines parallel to each other is broken. Even in the presence of the tape, the short grid line design in a different direction from the sub-grid lines can also conduct the current to the adjacent sub-grid lines, and then transmit it to the solder tape (wire) to avoid insulation.

[0017] The double-sided transparent tape provided by the present invention only needs to be located within the area of the short grid lines, and there is no special limitation on the position of the tape, as long as it can tightly bond the solder tape and the solar cell together.

[0018] The present invention connects the solder tape and the solar cell through the double-sided transparent tape, and with a special grid line design, the solder tape can be easily bonded to the solar cell, replacing the original welding pad points (metal solder joints) to form a solar cell string, reducing the amount of silver paste used and at the same time reducing the shading loss. Moreover, it can be obtained by changing some accessories on the current welding machine, and the method is simple and convenient; the tape is located between the solder tape and the solar cell, which will not affect the conduction of the photocurrent of the solar cell under the tape, and there is no need to combine the tape with the solder tape first, greatly simplifying the preparation process.

[0019] Preferably, the transmittance of the double-sided transparent tape > 50%, such as 51%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99%, etc.

[0020] The transmittance of the double-sided transparent tape provided by the present invention is the transmittance after lamination when the solar cell string is applied to the photovoltaic module.

[0021] In the present invention, if the transmittance of the double-sided transparent tape is too low, it will cause shading loss and affect the power generation efficiency.

[0022] Preferably, the double-sided transparent tape is arranged in a direction perpendicular to the direction parallel to the solder ribbon.

[0023] Preferably, the direction of the short grid line is perpendicular to the direction parallel to the sub-grid line.

[0024] Preferably, the width of the double-sided transparent tape is 0.1 - 30 mm, such as 0.1 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm or 30 mm, etc.

[0025] Preferably, the number of the double-sided transparent tapes ≥ 2, such as 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 20, etc.

[0026] The number of the double-sided transparent tapes pointed out in the present invention refers to the number of tapes in each solar cell in the solar cell string. The number of tapes can also be understood as the number of rows or columns of tapes on the solar cell. The number of tapes matches the width of the tape. The narrower the width, the more tapes can be arranged adaptively.

[0027] Preferably, the number of the solder ribbons ≥ 1, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 or 35, etc.

[0028] Preferably, the solder ribbon includes a wire and a coating covering the surface of the wire.

[0029] In the present invention, in order not to increase the series resistance, the number of wires is negatively correlated with the size. The thinner the wire, the more wires are needed.

[0030] Preferably, the diameter of the wire is 0.1 to 400 μm, such as 0.1 μm, 1, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm or 400 μm, etc., and preferably 100 to 300 μm.

[0031] Preferably, the coating includes a single metal coating and / or an alloy coating.

[0032] In the present invention, the coating in the solder ribbon plays a role in welding with the grid lines of the solar cell. Therefore, different wrapping layers are used to correspond to different welding temperatures, thereby affecting the lamination temperature.

[0033] Preferably, the melting point of the alloy coating is 50 to 200 °C, such as 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C or 200 °C, etc., and preferably 100 to 160 °C.

[0034] In the present invention, an alloy coating with a melting point of 120 to 160 °C is selected to adapt to the lamination temperature during the subsequent preparation of the photovoltaic module. During the lamination process, when the melting point temperature of the alloy coating is lower than the lamination temperature, the alloy coating will melt, flow downward along the wire, and converge towards the grid lines of the solar cell, achieving cooling welding. The main part of the wire can be either a copper wire or other wires with good conductivity, and preferably a copper wire.

[0035] Preferably, the length of the short grid line is greater than the width of the double-sided transparent tape.

[0036] In the present invention, it is ensured that the length of the short grid line is greater than the width of the double-sided transparent tape, so that the situation where the solder ribbon is insulated from the sub-grid lines perpendicular to the solder ribbon will not occur.

[0037] Preferably, the material of the short grid line is the same as that of the sub-grid line.

[0038] Preferably, the pasting area of the double-sided transparent tape is smaller than the area of the short grid line.

[0039] In a second aspect, the present invention provides a method for preparing a solar cell string according to the first aspect, and the preparation method includes:

[0040] A short grid line perpendicular to the direction parallel to the sub-grid lines is provided at the position where the double-sided transparent tape is placed on the solar cell, and then the double-sided transparent tape is pasted on the surface of the solar cell along the direction parallel to the sub-grid lines. The welding tape is placed on the surface of the double-sided transparent tape, and the solar cells are connected in series by the welding tape to obtain the solar cell string.

[0041] Preferably, after the welding tape is placed on the surface of the double-sided transparent tape, pressure is applied to the welding tape.

[0042] In a third aspect, the present invention also provides a photovoltaic module, which includes a first glass, a first encapsulant film, the solar cell string as described in the first aspect, a second encapsulant film, and a second glass that are stacked in sequence.

[0043] Preferably, a third encapsulant film is provided between the first encapsulant film and the solar cell string as described in the first aspect.

[0044] Preferably, a fourth encapsulant film is provided between the solar cell string as described in the first aspect and the second encapsulant film.

[0045] In the present invention, on the basis of the original encapsulant film, a new encapsulant film is further added for coverage. The purpose of coverage is to avoid direct contact between the battery and the first and second encapsulant films. At the same time, the third and fourth encapsulant films are relatively thin and will not hinder the first and second encapsulant films from filling the gaps, and can also improve the electrical contact, because the first and second encapsulant films have strong fluidity at the lamination temperature. The situation where the first and second encapsulant films insulate the welding tape and the grid lines during the lamination process is avoided.

[0046] Preferably, the thicknesses of the third encapsulant film and the fourth encapsulant film are each independently 0.1 to 100 μm, such as 0.1 μm, 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, etc.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] In the present invention, the welding tape and the solar cell are connected by a double-sided transparent tape, and with a special grid line design, the welding tape can be easily adhered to the solar cell, replacing the original welding pad points (metal solder joints) to form a solar cell string, reducing the amount of silver paste used and reducing the shading loss at the same time, and can be obtained by changing some accessories on the current welding machine, and the method is simple and convenient; the tape is located between the welding tape and the battery and will not affect the extraction of the photocurrent of the solar cell under the tape, nor is it necessary to combine the tape with the welding tape first, greatly simplifying the preparation process. Description of the Drawings

[0049] Figure 1It is a schematic structural diagram of a single solar cell in the solar cell string provided in the specific embodiment.

[0050] Figure 2 It is a partial schematic diagram of the side view of the solar cell string provided in the specific embodiment.

[0051] Figure 3 It is a schematic structural diagram of the solar cell string provided in the specific embodiment.

[0052] 1 - Solar cell, 2 - Solder ribbon, 3 - Double-sided transparent tape, 4 - Short grid line. Specific embodiment

[0053] The embodiments of the present invention will be described in detail below. The same or similar reference numerals represent the same or similar components or components with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as a limitation of the present invention.

[0054] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "installed" should be understood in a broad sense. For example, it can be an installation connection, a detachable connection, a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium. It can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In the description of the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first feature and the second feature, or may include the situation where the first feature and the second feature are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature is at a higher horizontal height than the second feature. The first feature being "below", "below", and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature is at a lower horizontal height than the second feature.

[0056] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as a specific limitation of the present invention.

[0057] In a specific embodiment, the present invention provides a solar cell string (as Figure 3 shown) and its preparation method, as Figure 1As shown, the solar cell string includes solar cells 1 and solder tapes 2 that connect the solar cells 1 in series. The solder tapes 2 are bonded to the surface of the solar cells 1 (as Figure 2 shown) through double-sided transparent tapes 3. The double-sided transparent tapes 3 are located between the solder tapes 2 and the solar cells 1. At the positions where the double-sided transparent tapes 3 are placed on the solar cells 1, short grid lines 4 in a direction different from that of the sub-grid lines are provided. Further, the direction of the short grid lines 4 is perpendicular to the direction parallel to the sub-grid lines.

[0058] The transmittance of the double-sided transparent tape 3 > 50%; the double-sided transparent tape 3 is arranged in the direction perpendicular to the parallel direction of the solder tape 2, and the width of the double-sided transparent tape 3 is 0.1 - 30 mm; the number of the double-sided transparent tapes 3 ≥ 2.

[0059] The number of the solder tapes 2 ≥ 1; the solder tape 2 includes a wire and a coating covering the surface of the wire; the diameter of the wire is 0.1 - 400 μm, further 100 - 300 μm; the coating includes a single metal coating and / or an alloy coating; the melting point of the alloy coating is 50 - 200 °C, further 100 - 160 °C.

[0060] The length of the short grid line 4 is greater than the width of the double-sided transparent tape 3; the material of the short grid line 4 is the same as that of the sub-grid line; the pasting area of the double-sided transparent tape 3 is smaller than the area of the short grid line 4.

[0061] The preparation method includes:

[0062] At the positions where the double-sided transparent tapes 3 are placed on the solar cells 1, short grid lines 4 perpendicular to the parallel direction of the sub-grid lines are set. Then, the double-sided transparent tapes 3 are pasted on the surface of the solar cells 1 along the parallel direction of the sub-grid lines. The solder tapes 2 are placed on the surface of the double-sided transparent tapes 3, pressure is applied to the solder tapes 2, and the solar cells 1 are connected in series with the solder tapes 2 to obtain the solar cell string.

[0063] In another specific embodiment, the present invention provides a photovoltaic module, which includes a first glass, a first encapsulant film, the solar cell string provided as in the above specific embodiment, a second encapsulant film, and a second glass that are sequentially stacked.

[0064] A third encapsulant film is provided between the first encapsulant film and the solar cell string provided as in the above specific embodiment;

[0065] A fourth encapsulant film is provided between the solar cell string provided as in the above specific embodiment and the second encapsulant film;

[0066] The thicknesses of the third encapsulant film and the fourth encapsulant film are independently 0.1 - 100 μm.

[0067] Example 1

[0068] This embodiment provides a solar cell string and a preparation method thereof, based on a solar cell string and a preparation method thereof provided in the specific implementation manner:

[0069] Among them, the transmittance of the double-sided transparent tape 3 is 88%; the width of the double-sided transparent tape 3 is 3 mm; the number of the double-sided transparent tape 3 is 10.

[0070] The number of the welding tapes 2 is 18; the welding tape 2 includes a wire and a coating covering the surface of the wire; the diameter of the wire is 260 μm; the coating is an alloy coating; the melting point of the alloy coating is 120 °C; the length of the short grid line 4 is 5 mm.

[0071] This embodiment also provides a photovoltaic module, based on a photovoltaic module provided in the specific implementation manner:

[0072] Among them, the thicknesses of the third adhesive film and the fourth adhesive film are 50 μm.

[0073] Example 2

[0074] This embodiment provides a solar cell string and a preparation method thereof, based on a solar cell string and a preparation method thereof provided in the specific implementation manner:

[0075] Among them, the transmittance of the double-sided transparent tape 3 is 90%; the width of the double-sided transparent tape 3 is 4 mm; the number of the double-sided transparent tape 3 is 8.

[0076] The number of the welding tapes 2 is 20; the welding tape 2 includes a wire and a coating covering the surface of the wire; the diameter of the wire is 240 μm; the coating is an alloy coating; the melting point of the alloy coating is 125 °C; the length of the short grid line 4 is 8 mm.

[0077] This embodiment also provides a photovoltaic module, based on a photovoltaic module provided in the specific implementation manner:

[0078] Among them, the thicknesses of the third adhesive film and the fourth adhesive film are 80 μm.

[0079] Example 3

[0080] This embodiment provides a solar cell string and a preparation method thereof, based on a solar cell string and a preparation method thereof provided in the specific implementation manner:

[0081] Among them, the transmittance of the double-sided transparent tape 3 is 91%; the width of the double-sided transparent tape 3 is 5 mm; the number of the double-sided transparent tape 3 is 6.

[0082] The number of the welding tapes 2 is 24; the welding tape 2 includes a wire and a coating covering the surface of the wire; the diameter of the wire is 180 μm; the coating is an alloy coating; the melting point of the alloy coating is 130 °C, and the length of the short grid line 4 is 7 mm.

[0083] This embodiment also provides a photovoltaic module, based on the photovoltaic module provided in the specific implementation manner:

[0084] Among them, the thicknesses of the third adhesive film and the fourth adhesive film are 10 μm.

[0085] Example 4

[0086] This embodiment provides a solar cell string and a method for manufacturing the same, based on a solar cell string and a method for manufacturing the same provided in the specific implementation manner:

[0087] Among them, the transmittance of the double-sided transparent tape 3 is 92%; the width of the double-sided transparent tape 3 is 7 mm; the number of the double-sided transparent tape 3 is 5.

[0088] The number of the solder ribbons 2 is 30; the solder ribbon 2 includes a wire and a coating covering the surface of the wire; the diameter of the wire is 140 μm; the coating is an alloy coating; the melting point of the alloy coating is 140 °C; the length of the short grid line 4 is 9 mm.

[0089] This embodiment also provides a photovoltaic module, based on the photovoltaic module provided in the specific implementation manner:

[0090] Among them, the thicknesses of the third adhesive film and the fourth adhesive film are 20 μm.

[0091] The present invention connects the solder ribbon and the solar cell through a double-sided transparent tape, and with a special grid line design, the solder ribbon can be easily adhered to the solar cell, replacing the original welded pad points (metal solder joints), forming a solar cell string, reducing the amount of silver paste used and reducing the shading loss at the same time, and can be obtained by changing some accessories on the current soldering machine, and the method is simple and convenient; the tape is located between the solder ribbon and the cell, which will not affect the extraction of the photocurrent of the solar cell under the tape, and it is not necessary to combine the tape with the solder ribbon first, greatly simplifying the manufacturing process.

[0092] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing a solar cell string, characterized in that, The preparation method includes: A short grid line perpendicular to the direction parallel to the sub-grid line is set at the position where the double-sided transparent tape is placed on the solar cell, and then the double-sided transparent tape is pasted on the surface of the solar cell along the direction parallel to the sub-grid line. The welding ribbon is placed on the surface of the double-sided transparent tape, and the solar cells are connected in series by the welding ribbon to obtain the solar cell string; The double-sided transparent tape is a non-conductive tape, and the double-sided transparent tape is located within the area of the short grid line; The solar cell string includes solar cells and welding ribbons that connect the solar cells in series. The welding ribbon is bonded to the surface of the solar cell by the double-sided transparent tape. The double-sided transparent tape is located between the welding ribbon and the solar cell. At the position where the double-sided transparent tape is placed on the solar cell, a short grid line in a direction different from that of the sub-grid line is set.

2. The manufacturing method of the solar cell string according to claim 1, wherein, The transmittance of the double-sided transparent tape > 50%; 3. The method for preparing a solar cell string according to claim 1, wherein The double-sided transparent tape is arranged along the direction perpendicular to the direction parallel to the welding ribbon; 4. The manufacturing method of the solar cell string according to claim 1, wherein, The direction of the short grid line is perpendicular to the direction parallel to the sub-grid line; 5. The manufacturing method of the solar cell string according to claim 1, wherein The width of the double-sided transparent tape is 0.1 - 30 mm; 6. The method for preparing a solar cell string according to claim 1, wherein, The number of the double-sided transparent tapes ≥ 2; 7. The method for preparing a solar cell string according to claim 1, characterized in that, The number of the welding ribbons ≥ 1; 8. The manufacturing method of the solar cell string according to claim 1, wherein, The welding ribbon includes a wire and a coating covering the surface of the wire; 9. The method for preparing a solar cell string according to claim 8, characterized in that, The diameter of the wire is 0.1 - 400 μm; 10. The manufacturing method of the solar cell string according to claim 9, characterized in that, The diameter of the wire is 100 - 300 μm; 11. The method for preparing a solar cell string according to claim 8, wherein, The coating includes a single metal coating and / or an alloy coating; 12. The method for manufacturing a solar cell string according to claim 11, wherein, The melting point of the alloy coating is 50 - 200 °C; 13. The method for preparing a solar cell string according to claim 12, wherein, Preferably, the melting point of the alloy coating is 100 - 160 °C; 14. The manufacturing method of the solar cell string according to claim 1, characterized in that, The length of the short grid line is greater than the width of the double-sided transparent tape; 15. The manufacturing method of the solar cell string according to claim 1, characterized in that, The material of the short grid line is the same as that of the sub-grid line; 16. The method for preparing a solar cell string according to claim 1, wherein The pasting area of the double-sided transparent tape is smaller than the area of the short grid line; 17. The method for preparing a solar cell string according to claim 1, characterized in that, After the welding ribbon is placed on the surface of the double-sided transparent tape, pressure is applied to the welding ribbon; 18. A photovoltaic module, characterized in that, The photovoltaic module includes a first glass, a first encapsulant film, a solar cell string prepared by the preparation method of the solar cell string according to any one of claims 1 - 17, a second encapsulant film, and a second glass which are stacked in sequence; 19. The photovoltaic module according to claim 18, characterized in that, A third encapsulant film is provided between the first encapsulant film and the solar cell string prepared by the preparation method of the solar cell string according to any one of claims 1 - 17; 20. The photovoltaic module according to claim 19, wherein, A fourth encapsulant film is provided between the solar cell string prepared by the preparation method of the solar cell string according to any one of claims 1 - 17 and the second encapsulant film; 21. The photovoltaic module according to claim 20, characterized in that, The thicknesses of the third encapsulant film and the fourth encapsulant film are independently 0.1 - 100 μm.

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