Photovoltaic module, preparation method and welding tool

Abstract

The invention discloses a photovoltaic module, a preparation method and a welding tool, and relates to the technical field of photovoltaic modules. The photovoltaic module comprises one or more battery strings, each battery string comprises a plurality of battery pieces, a plurality of high-temperature welding strips and a plurality of low-temperature welding strips, and the high-temperature welding strips and the low-temperature welding strips are connected with the battery pieces in series. Each battery piece is provided with a plurality of first main grids; each high-temperature welding strip is connected in series with two corresponding first main grids of two adjacent battery pieces; and each low-temperature welding strip is arranged between the two adjacent first main grids on the battery pieces and is connected with the two adjacent battery pieces in series. According to the embodiment, the high-temperature welding strip and the low-temperature welding strip are arranged in the photovoltaic module at the same time, and part of the main grids in the battery piece are reserved, so that the purposes of reducing the silver paste cost and the gram weight of an adhesive film can be achieved, and the problem that the photovoltaic module is prone to failure in the outdoor long-term operation process is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic modules, and in particular to a photovoltaic module, a preparation method and a welding tool. Background Art

[0002] Cost reduction and efficiency improvement has become one of the development directions of photovoltaic modules. At present, either the number of main grids is increased to reduce the diameter of the welding ribbon and the weight of the film, or the main grid is omitted and low-temperature welding ribbon is used directly to collect current from the fine grid to achieve the purpose of cost reduction and efficiency improvement of photovoltaic modules.

[0003] However, due to the increase in the number of main grids, the amount of silver paste required for printing the main grids increases, resulting in an increase in cost, which greatly limits the space for cost reduction. As for the structure that directly collects current through the low-temperature solder strip, since the low-temperature solder strip is in direct contact with the fine grid, the contact area is small, resulting in limited current collection capacity, and the low-temperature solder strip and the fine grid are prone to fall off and fail during use. Therefore, there is an urgent need for a photovoltaic module with low preparation cost and stable structure that is not prone to failure. Summary of the invention

[0004] In view of this, the embodiments of the present invention provide a photovoltaic module, a preparation method and a welding tool, which can not only reduce the cost of silver paste and the weight of the film, but also avoid the problem of photovoltaic modules being prone to failure during long-term outdoor operation.

[0005] To achieve the above object, according to one aspect of an embodiment of the present invention, a photovoltaic assembly is provided, comprising: one or more battery strings, wherein:

[0006] The battery string comprises a plurality of battery cells and a plurality of high-temperature welding strips and a plurality of low-temperature welding strips connecting the battery cells in series;

[0007] Each of the above-mentioned battery cells is provided with a plurality of first main grids;

[0008] Each of the high-temperature welding strips is connected in series with two first main grids corresponding to two adjacent battery cells;

[0009] Each of the low-temperature welding strips is disposed between two adjacent first main grids on the battery cell and is connected in series with two adjacent battery cells.

[0010] To achieve the above object, according to another aspect of an embodiment of the present invention, a method for preparing a photovoltaic module is provided, comprising:

[0011] Repeat the following steps N1 to N2 until the battery string is laid out:

[0012] N1. Lay one end of the high-temperature welding tape on the first main grid of the current battery cell; lay one end of the low-temperature welding tape between two adjacent first main grids of the current battery cell, and fix the low-temperature welding tape;

[0013] N2, laying another battery cell on the other end of the high-temperature welding strip and the other end of the low-temperature welding strip, and taking the other battery cell as the current battery cell, and executing N1;

[0014] The laid battery string is fixed by welding tooling, and the high temperature welding strips in the laid battery string are subjected to high temperature welding;

[0015] The welding tool is removed, and the battery string that has been subjected to high-temperature welding is laminated. During the lamination process, the low-temperature welding of the low-temperature welding strip is performed to obtain a welded battery string;

[0016] Assemble multiple welded cell strings into photovoltaic modules.

[0017] To achieve the above object, according to another aspect of an embodiment of the present invention, there is provided a welding tool for a photovoltaic module, which is applied to any of the above-mentioned methods for preparing a photovoltaic module, and comprises: a pressure discharge component and a welding support component;

[0018] The above-mentioned pressure-discharging component includes a connecting portion, a plurality of pressure blocks and a plurality of pressure needles, wherein the plurality of pressure needles are arranged at intervals on the above-mentioned connecting portion, and the plurality of pressure blocks are arranged on the above-mentioned connecting portion and are located between adjacent pressure needles;

[0019] The welding support component comprises a heating device, a bottom plate and a heat-insulating interlayer spaced apart on the bottom plate; the heating device is connected to the bottom plate;

[0020] During the use of the above-mentioned welding tooling, the above-mentioned pressure-discharging component is placed above the laid battery string; the above-mentioned welding support component is used to support the laid battery string; wherein the above-mentioned pressure needle portion corresponds to the high-temperature welding strip on the upper surface of the laid battery string; the above-mentioned pressure block portion corresponds to the low-temperature welding strip on the upper surface of the laid battery string; the above-mentioned thermal insulation interlayer corresponds to the low-temperature welding strip on the lower surface of the laid battery string; the above-mentioned heating device provides heat to the above-mentioned bottom plate to perform high-temperature welding on the high-temperature welding strips in the laid battery string.

[0021] An embodiment of the above invention has the following advantages or beneficial effects: by simultaneously arranging high-temperature welding strips and low-temperature welding strips in the photovoltaic module and retaining part of the main grid in the battery cell, it is possible to reduce the cost of silver paste and the weight of the adhesive film, and avoid the problem of easy failure of the photovoltaic module during long-term outdoor operation.

[0022] The further effects of the above-mentioned non-conventional optional manner will be described below in conjunction with the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0024] Figure 1 It is a schematic diagram of the structure of a cell in the first photovoltaic module in the prior art;

[0025] Figure 2 It is a structural schematic diagram of the location of the main grid welding contact point in the first photovoltaic module in the prior art;

[0026] Figure 3 It is a schematic diagram of the connection structure between the low-temperature welding strip and the fine grid in the second photovoltaic module in the prior art;

[0027] Figure 4 is a schematic diagram of a first structure of a cell sheet of a photovoltaic module according to an embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of a second structure of a cell sheet of a photovoltaic module according to an embodiment of the present invention;

[0029] Figure 6 is a third structural schematic diagram of a cell sheet of a photovoltaic module according to an embodiment of the present invention;

[0030] Figure 7 is a fourth structural schematic diagram of a cell sheet of a photovoltaic module according to an embodiment of the present invention;

[0031] Figure 8 is a fifth structural schematic diagram of a cell of a photovoltaic module according to an embodiment of the present invention;

[0032] Fig. 9 is a sixth structural schematic diagram of a cell of a photovoltaic module according to an embodiment of the present invention;

[0033] Fig.10 is a schematic flow chart of a method for preparing a photovoltaic module according to an embodiment of the present invention;

[0034] Fig.11 is a schematic structural diagram of a battery cell with a high-temperature welding strip and a low-temperature welding strip laid thereon according to an embodiment of the present invention;

[0035] Fig.12 is a schematic diagram of laying a battery string by glue point gluing according to an embodiment of the present invention;

[0036] Fig.13 is a schematic diagram of a structure for laying a high-temperature solder strip and a low-temperature solder strip in a battery cell on which glue dots are printed according to an embodiment of the present invention;

[0037] Fig.14 is a schematic diagram of laying a battery string by using a tape gluing method according to an embodiment of the present invention;

[0038] Fig.15is a schematic diagram of a structure in which a low-temperature soldering tape is fixed to a battery cell using an adhesive tape according to an embodiment of the present invention;

[0039] Fig.16 is a schematic structural diagram of a pressure discharge component according to an embodiment of the present invention;

[0040] Fig.17 is a schematic structural diagram of a welding support component according to an embodiment of the present invention;

[0041] Fig.18 is a structural schematic diagram of a needle pressing part according to an embodiment of the present invention;

[0042] Fig.19 is a schematic diagram of a first structure of a pressing block portion according to an embodiment of the present invention;

[0043] Fig. 20 2 is a schematic diagram of a second structure of a pressing block part according to an embodiment of the present invention.

[0044] Reference numerals:

[0045] 1-first main grid; 101-first main grid line; 102-main grid welding contact point; 2-high temperature welding strip; 3-fine grid; 301-fine grid welding contact point; 302-first fine grid segment; 303-second fine grid segment; 4-segmented main grid; 5-second main grid; 6-low temperature welding strip; 7-glue point; 8-tape; 9-pressure discharge component; 901-connecting part; 9011-first connecting part; 9012-second connecting part; 902-pressing block part; 9021-reflective layer; 9022-insulating pad; 90221-groove; 903-pressing needle part; 9031-elastic member; 90311-circlip; 90312-spring; 9032-pressing needle body; 904-frame; 10-welding support component; 1001-heating device; 1002-bottom plate; 1003-insulating interlayer. DETAILED DESCRIPTION

[0046] In photovoltaic modules, the film can be filled between the photovoltaic cell array formed by the cell sheet and the welding ribbon and the glass to reduce vibration and buffer the stress generated by the photovoltaic cell array due to environmental factors such as temperature changes during the use of the photovoltaic module, so as to provide stable mechanical support for the photovoltaic module. While maintaining the performance of the photovoltaic module, the number of welding ribbons per unit area of ​​the photovoltaic cell array can be increased, and the gap and height difference between the photovoltaic cell array and the glass can be reduced. The thinner welding ribbon has a relatively small change in the degree of expansion and contraction caused by temperature, and the stress generated on the film is more uniform. Therefore, when the diameter of the welding ribbon is small and the number is large, a thinner film can be used, thereby reducing the weight of the film.

[0047] At present, there are mainly two types of commonly used photovoltaic modules.

[0048] The first is to lay high temperature welding strips 2 on the cells with the first main grid 1 spaced apart, and perform high temperature welding to obtain a photovoltaic module. In this case, the layout of the cell can be as follows: Figure 1 As shown, the first busbars 1 on the cell are evenly distributed at the same intervals, and each first busbar 1 includes a first busbar line 101 and busbar welding contact points 102 (busbar PAD points) distributed at intervals. Figure 2 As shown, in this photovoltaic module, the high-temperature welding ribbon 2 can be spread on the position of the main grid welding contact point 102 after high-temperature welding, and form a firm contact with the main grid welding contact point 102. Therefore, this photovoltaic module has the advantage of high reliability. However, since all the main grids are retained in the battery cell, the cost reduction space of the silver paste is greatly limited. In addition, due to cost constraints, the first main grid 1 in the battery cell is generally 16BB, which makes it impossible to further increase the number of high-temperature welding ribbons 2, and it is also difficult to achieve cost reduction of the gram weight of the adhesive film.

[0049] The second type is to lay low-temperature welding tape 6 on the cell without the first main grid 1 and only with the fine grid 3, and perform low-temperature welding to obtain a photovoltaic module. Since such a photovoltaic module does not have a main grid, the cost of using silver paste is greatly reduced, the number of low-temperature welding tapes 6 can reach 24, and the weight of the film can also be reduced. At the same time, if Figure 3 As shown, the low-temperature welding strip 6 is in direct contact with the fine grid 3, the contact area is small, it is difficult to form alloy, the reliability is low, and there may even be a gap between the low-temperature welding strip 6 and the fine grid 3, so that the low-temperature welding strip 6 is easy to fall off and fail during outdoor use of the photovoltaic module, affecting the current collection capacity and the life of the photovoltaic module.

[0050] In order to solve the above problems existing in the prior art, the embodiments of the present invention provide a novel photovoltaic module and a preparation method thereof, and a grid line preparation tool.

[0051] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0052] It should be pointed out that the embodiments of the present invention and the technical features therein may be combined with each other without conflict.

[0053] It should be noted that the electrical connection involved in the embodiments of the present invention refers to a connection method that can achieve electrical conduction, which can be a direct connection or an indirect connection.

[0054] The photovoltaic assembly of the embodiment of the present invention mainly includes: one or more battery strings, wherein the battery string includes a plurality of battery cells and a plurality of high-temperature welding strips 2 and a plurality of low-temperature welding strips 6 connecting the battery cells in series. Figure 4 FIG. 1 is a schematic diagram of a first structure of a cell sheet of a photovoltaic module according to an embodiment of the present invention. Figure 4 As shown, each of the above-mentioned battery cells is provided with multiple first main grids 1; each of the above-mentioned high-temperature welding strips 2 is connected in series with the two corresponding first main grids 1 of the two adjacent above-mentioned battery cells; each of the above-mentioned low-temperature welding strips 6 is arranged between the two adjacent above-mentioned first main grids 1 on the above-mentioned battery cell, and is connected in series with the two adjacent above-mentioned battery cells.

[0055] On each cell, a plurality of first main grids 1 extend from one end of the cell to the other end along a first direction and are arranged at intervals. The intervals between the plurality of first main grids 1 may be the same or different. Each first main grid 1 may include a first main grid line 101 and a plurality of main grid welding contact points 102 arranged at intervals. A plurality of fine grids 3 are arranged on each cell, and the plurality of fine grids 3 extend from one end of the cell to the other end along a second direction, wherein the second direction is perpendicular to the first direction.

[0056] The high temperature welding strip 2 covers the first main grid 1, and the low temperature welding strip 6 is arranged between two adjacent first main grids 1. It can be understood that there can be multiple first main grids 1 between two low temperature welding strips 6, that is, there can be multiple high temperature welding strips 2.

[0057] Preferably, if Figure 5 As shown, the high-temperature welding strips 2 and the low-temperature welding strips 6 are arranged at intervals, that is, each high-temperature welding strip 2 is arranged between two adjacent low-temperature welding strips 6 and covers the first main grid 1, and each low-temperature welding strip 6 is arranged between two adjacent high-temperature welding strips 2, that is, between two adjacent first main grids 1.

[0058] In the photovoltaic module, each high-temperature welding strip 2 connects in series the two first main grids 1 corresponding to two adjacent cells. For example, in cell a, a high-temperature welding strip 2 covers the first first main grid 1. In cell b adjacent to cell a, the high-temperature welding strip 2 should also cover its first first main grid 1, so as to connect in series the first first main grid 1 corresponding to the adjacent cells a and b. Similarly, on adjacent cells of the photovoltaic module, each low-temperature welding strip 6 is arranged between the two adjacent first main grids 1 corresponding to the two adjacent cells. For example, in cell a, a low-temperature welding strip 6 is arranged between the first first main grid 1 and the second first main grid 1 adjacent to the first first main grid 1. In cell b adjacent to cell a, the low-temperature welding strip 6 should also be arranged between the first first main grid 1 and the second first main grid 1, so as to connect in series the cells a and the cells b.

[0059] In addition, in order to achieve cost reduction of photovoltaic modules while ensuring the reliability of long-term outdoor operation of photovoltaic modules, the total number of high-temperature welding strips 2 and low-temperature welding strips 6 set on the surface of each cell string of the photovoltaic module can be 16 to 30. As an example, the total number of high-temperature welding strips 2 and low-temperature welding strips 6 set on the surface of each cell string of the photovoltaic module can be 16, 20, 25 or 30.

[0060] By simultaneously providing the high-temperature welding strip 2 and the low-temperature welding strip 6 in the photovoltaic module, the reliability of the photovoltaic module in long-term outdoor operation is ensured. Even if the low-temperature welding strip 6 falls off during long-term operation, there is still a high-temperature welding strip 2 with reliable contact, and the current can be collected through the high-temperature welding strip 2, avoiding the problem of reducing the life of the photovoltaic module due to the falling off of the low-temperature welding strip 6. At the same time, since multiple low-temperature welding strips 6 are provided, the number of main grids is reduced, the use cost of silver paste and the weight of the film are reduced, and the cost of photovoltaic modules is reduced.

[0061] In an optional embodiment, the number of the high-temperature welding strips 2 on the surface of the battery string is greater than or equal to the number of the low-temperature welding strips 6 .

[0062] In order to ensure the reliability of photovoltaic modules in long-term outdoor use and avoid the reduction of current collection capacity due to the falling of low-temperature welding strips 6, the number of high-temperature welding strips 2 on the surface of each battery string should be greater than or equal to the number of low-temperature welding strips 6.

[0063] In an optional embodiment, the battery cell further comprises: a fine grid welding contact point 301 is provided between two adjacent first main grids 1. The low temperature welding strip 6 is electrically connected to the welding contact point between the two adjacent first main grids 1.

[0064] Specifically, Figure 6 As shown, one or more fine grid welding contact points 301 are arranged between two adjacent first main grids 1. In the case where there are multiple fine grid welding contact points 301, the multiple fine grid welding contact points 301 are arranged at intervals along the extension direction of the first main grid 1, that is, the first direction. In the upper surface or lower surface of each solar cell, the total area of ​​all fine grid welding contact points 301 is less than 0.5mm 2 , thereby ensuring that the silver paste cost can be reduced in this case. As an example, in the upper surface or lower surface of each battery cell, the total area of ​​all fine grid welding contacts 301 can be 0.1mm 2 , 0.2mm 2 , 0.4mm 2 or 0.5mm 2 wait.

[0065] In the photovoltaic module, the low temperature welding tape 6 is electrically connected to the fine grid welding contact point 301 provided between two adjacent first main grids 1. In the case of multiple fine grid welding contact points 301, the low temperature welding tape 6 is deployed along the multiple fine grid welding contact points 301 between two adjacent first main grids 1.

[0066] It should be noted that the fine grid welding contact point 301 should be set in the fine grid 3 to assist in enhancing the contact reliability between the fine grid 3 and the low-temperature welding strip 6 and at the same time improve the current collection capacity of the low-temperature welding strip 6.

[0067] In an optional embodiment, if Figure 7 As shown, the cell further comprises: a plurality of segmented main grids 4 are arranged between two adjacent first main grids 1. The low temperature welding strips 6 are arranged along the plurality of segmented main grids 4 and are electrically connected to the plurality of segmented main grids 4.

[0068] Each segmented main grid 4 may have a length of 2-50 mm and a width of 10-20 μm, and each segmented main grid 4 should be electrically connected to at least one fine grid 3 to collect the current on the fine grid 3. As an example, the length of each segmented main grid 4 may be 2 mm, 10 mm, 25 mm or 50 mm, and the width of each segmented main grid 4 may be 10 μm, 13 μm, 15 μm or 20 μm, etc.

[0069] The segmented main grid 4 extends along the first direction and is arranged in parallel with the first main grid 1. The low-temperature welding strip 6 is deployed along several segmented main grids 4 and covers several segmented main grids 4, and collects current from the fine grid 3 electrically connected thereto and several segmented main grids 4 covered therewith. By setting the segmented main grid 4, the possibility of the low-temperature welding strip 6 falling off is reduced, the current collection capacity is improved, and the silver paste cost is reduced by controlling the length and width of the segmented main grid 4.

[0070] In an optional embodiment, if Figure 8 As shown, the cell further comprises: a second main grid 5 is arranged between two adjacent first main grids 1 . The low temperature welding strip 6 is arranged along the second main grid 5 and electrically connected to the second main grid 5 .

[0071] The width of the second main grid 5 is smaller than the width of the first main grid 1. Preferably, the width of the second main grid 5 may be 10-20 μm. As an example, the width of the second main grid 5 may be 10 μm, 12 μm, 16 μm or 20 μm.

[0072] The second main grid 5 extends from one end of the cell to the other end along the first direction, and is arranged in parallel with the first main grid 1. The second main grid 5 is electrically connected to each thin grid 3 on the cell to collect the current on the thin grid 3. The low-temperature welding strip 6 is deployed along the second main grid 5 and covers the second main grid 5 to collect current from the second main grid 5. By setting the second main grid 5, the possibility of the second welding strip falling off is reduced, and the current collection capacity is further improved. By controlling the width of the second main grid 5 to be smaller than the width of the first main grid 1, the cost of silver paste is reduced.

[0073] In an optional embodiment, if Fig. 9 As shown, the thin grid 3 included in the above-mentioned battery cell includes a first thin grid segment 302 and a second thin grid segment 303 arranged alternately, wherein the width of the above-mentioned second thin grid segment 303 is greater than the width of the above-mentioned first thin grid segment 302; the above-mentioned first main grid 1 is electrically connected to the above-mentioned first thin grid segment 302. The above-mentioned low-temperature welding belt 6 is electrically connected to the above-mentioned second thin grid segment 303.

[0074] Specifically, the fine grid 3 of the cell comprises a first fine grid segment 302 and a second fine grid segment 303 having a width greater than that of the first fine grid segment 302 . There may be one or more second fine grid segments 303 in each fine grid 3 .

[0075] The width of the second fine grid segment 303 may be 10-80 μm. As an example, the width of the second fine grid 3 may be 10 μm, 30 μm, 50 μm or 80 μm, etc. By controlling the width of the second fine grid segment 303, the contact area between the low-temperature welding strip 6 and the second fine grid segment 303 may be increased, and the current collection capability of the second fine grid segment 303 may be improved.

[0076] In addition, the length of the second fine grid segment 303 can be 1-2 mm, and the total number of the second fine grid segments 303 on the upper surface or the lower surface of each cell can be 3-200. As an example, the length of the second fine grid segment 303 can be 1 mm, 1.5 mm or 2 mm, etc.; the total number of the second fine grid segments 303 on the upper surface or the lower surface of each cell can be 3, 20, 80, 150, 200, etc. By controlling the length of the second fine grid segment 303 and the total number of the second fine grid segments 303 on each surface of the cell, the cost of silver paste can be reduced.

[0077] In an optional embodiment, it is possible to Figure 4 or Figure 5 As shown, in the battery cell, no fine grid welding contact point 301, segmented main grid 4 or second main grid 5 may be arranged between two adjacent first main grids 1. In addition, the above-mentioned fine grid 3 may only include a first fine grid segment 302, so that the low-temperature welding strip 6 is directly arranged between two adjacent first main grids 1 and electrically connected to the fine grid 3, thereby further reducing the silver paste cost.

[0078] It can be understood that, as described above, the fine grid 3, the segmented main grid 4 or the second main grid 5 are arranged between two adjacent first main grids 1, and the fine grid 3 may include a first fine grid segment 302 and a second fine grid segment 303, and several structures can be arranged simultaneously in the same cell. As an example, on the surface of a certain cell, a number of welding contacts can be arranged between the adjacent first first main grid 1 and the second first main grid 1, and a second main grid 5 can be arranged between the adjacent second first main grid 1 and the third first main grid 1. As another example, on the surface of a certain cell, a number of segmented main grids 4 and a number of fine grid welding contacts 301 can be arranged between the adjacent second first main grid 1 and the third first main grid 1, and at the same time, the fine grid 3 includes a first fine grid segment 302 and a second fine grid segment 303.

[0079] In an optional embodiment, the thickness of the above-mentioned cell is 80-140 μm. By simultaneously providing the low-temperature welding strip 6 and the high-temperature welding strip 2 in the cell string of the photovoltaic module, the number of the first main grid 1 is reduced, the number of welding strips is increased, and ultra-thin welding strips can be used, which is suitable for thin cells.

[0080] Optionally, the high temperature solder strip 2 includes but is not limited to a solder strip with a solder strip coating of SnPb alloy, the diameter may be 0.1-0.26 mm, and the melting point may be greater than 180° C. As an example, the diameter of the high temperature solder strip 2 may be 0.1 mm, 0.15 mm, 0.20 mm, or 0.26 mm, etc., and the melting point may be 181° C., 185° C., or 190° C., etc.

[0081] Optionally, the low-temperature solder strip 6 includes but is not limited to a solder strip with a solder strip coating of SnPbBi alloy, the diameter may be 0.1-0.26 mm, and the melting point may be 120-160° C. As an example, the diameter of the low-temperature solder strip 6 may be 0.1 mm, 0.16 mm, 0.22 mm, or 0.26 mm, and the melting point may be 120° C., 130° C., 140° C., or 160° C., etc.

[0082] The cells in the photovoltaic module may be Passivated Emitter and Rear Cell (PERC), Hetero Junction Technology (HJT), Tunnel Oxide Passivating Contacts (TOPCon) or Back Contact (BC), but are not limited thereto.

[0083] According to the photovoltaic module of the embodiment of the present invention, by simultaneously arranging the high-temperature welding strip 2 and the low-temperature welding strip 6 in the photovoltaic module, only a part of the main grid in the battery cell is retained, thereby increasing the number of welding strips to a certain extent. Both the high-temperature welding strip 2 and the low-temperature welding strip 6 can use welding strips with smaller diameters, thereby achieving the purpose of reducing the silver paste cost and the gram weight of the adhesive film. At the same time, the retention of the high-temperature welding strip 2 can also avoid the problem of easy failure of the photovoltaic module during long-term outdoor operation, so that the photovoltaic module has good stability.

[0084] Even if the low-temperature welding strip 6 falls off during long-term outdoor operation, current collection can be achieved through the high-temperature welding strip 2, which increases the life of the photovoltaic module compared to a photovoltaic module that only has the low-temperature welding strip 6.

[0085] Fig.10 FIG. 1 is a schematic diagram of a process for preparing a photovoltaic module according to an embodiment of the present invention. Fig.10 As shown, the method for preparing a photovoltaic module according to an embodiment of the present invention includes the following steps A1 to A4:

[0086] Step A1, loop through the following steps N1 to N2 until a battery string is laid out:

[0087] N1. Lay one end of the high-temperature welding tape 2 on the first main grid 1 of the current battery cell; lay one end of the low-temperature welding tape 6 between two adjacent first main grids 1 of the current battery cell, and fix the low-temperature welding tape 6;

[0088] N2, laying another battery cell on the other end of the high temperature welding strip 2 and the other end of the low temperature welding strip 6, and taking the other battery cell as the current battery cell, executing N1;

[0089] Step A2, using welding tools to fix the laid battery string, and performing high-temperature welding on the high-temperature welding strips 2 in the laid battery string;

[0090] Step A3, removing the welding tool, laminating the battery string that has been subjected to high temperature welding, and performing low temperature welding of the low temperature welding strip 6 during the lamination process to obtain a battery string that has been welded;

[0091] Step A4, assembling the welded multiple battery strings into a photovoltaic module.

[0092] In order to simplify the preparation process of the photovoltaic module provided with the high temperature welding strip 2 and the low temperature welding strip 6, the high temperature welding strip 2 and the low temperature welding strip 6 can be laid in the adjacent battery cells in the string welding machine, and multiple battery cells can be interconnected to form a battery string. In this way, the laid battery string can be directly subjected to high temperature welding, and the high temperature welding strip 2 can be subjected to high temperature welding during the high temperature welding process to achieve alloying of the high temperature welding strip 2 and the first main grid 1. After high temperature welding, the battery string after high temperature welding can be arranged into an arrangement structure corresponding to the battery string in the photovoltaic module, and then laminated. During the lamination process, the low temperature welding strip 6 is subjected to low temperature welding at the temperature during lamination to achieve alloying of the low temperature welding strip 6 and the fine grid 3. After lamination, operations such as framing can be performed to obtain a photovoltaic module. Therefore, the embodiment of the present invention realizes low temperature welding by utilizing the lamination temperature during the lamination process, and there is no need to increase the preparation process for the photovoltaic module provided with both the high temperature welding strip 2 and the low temperature welding strip 6. Among them, high temperature welding can be infrared welding, but is not limited thereto.

[0093] Specifically, taking a battery cell in which the positive electrode and the negative electrode are respectively arranged on the upper surface and the lower surface, and a battery cell in which the positive electrode and the negative electrode are both arranged on the lower surface as examples, step A1 is described in detail:

[0094] For a battery cell with the positive electrode and the negative electrode disposed on the upper surface and the lower surface respectively, step A1 specifically includes: firstly, laying a high-temperature welding strip 2 and a low-temperature welding strip 6 on a string welding machine, referring to Fig.11 , place the current cell on the laid high-temperature welding tape 2 and low-temperature welding tape 6, so that the high-temperature welding tape 2 corresponds to the first main grid 1 of the current cell, and the low-temperature welding tape 6 corresponds to the position between two adjacent first main grids 1, that is, the welding tape laying on the lower surface of the current cell is completed. N1, lay the high-temperature welding tape 2 and the low-temperature welding tape 6 at the corresponding position on the upper surface of the current cell. N2, lay another cell, and correspond each first main grid 1 of the other cell to each first main grid 1 of the above-mentioned current cell, so that the two cells are placed correspondingly, and the other end of the high-temperature welding tape 2 and the low-temperature welding tape 6 on the upper surface of the above-mentioned current cell is located on the lower surface of the above-mentioned other cell. Take the above-mentioned other cell as the current cell, and repeat steps N1 and N2 until a cell string is laid.

[0095] For a battery cell in which both the positive and negative electrodes are arranged on the lower surface, step A1 specifically includes: N1, laying high-temperature welding tape 2 and low-temperature welding tape 6 on the string welding machine, laying the current battery cell on the laid high-temperature welding tape 2 and low-temperature welding tape 6, so that the high-temperature welding tape 2 corresponds to the first main grid 1 of the current battery cell, and the low-temperature welding tape 6 corresponds to the position between two adjacent first main grids 1, that is, the welding tape laying of the current battery cell is completed. N2, laying another battery cell, each first main grid 1 of the other battery cell corresponds to each first main grid 1 of the above-mentioned current battery cell, so that the two battery cells are placed correspondingly, and the other end of the high-temperature welding tape 2 and the low-temperature welding tape 6 of the above-mentioned current battery cell is located at the corresponding position on the lower surface of the above-mentioned other battery cell. Take the above-mentioned other battery cell as the current battery cell, lay the high-temperature welding tape and the low-temperature welding tape on the surface of the current battery cell and the next battery cell, and repeat steps N1 and N2 until the battery string is laid.

[0096] It should be noted that, for the battery cells that are not at the edge of the battery string, one end of each welding strip connects the positive electrode of the current battery cell with the negative electrode of another battery cell; for the two battery cells at the edge of the battery string, the welding strips that are not connected to the adjacent battery cells are connected to the bus bar.

[0097] After the battery string on the string welding machine is laid, the battery string is fixed by a welding tool to prevent the high temperature welding strip 2 and the low temperature welding strip 6 from shifting, and the low temperature welding strip 6 is thermally insulated, and the battery string is high temperature welded by the cooperation of the welding tool and the string welding machine, so that the high temperature welding strip 2 forms a reliable contact with the first main grid 1. In addition, during the high temperature welding process, it is necessary to ensure that the low temperature welding strip 6 and the fine grid 3 are not alloyed, so as to avoid the alloying of the low temperature welding strip 6 and the fine grid 3 at high temperature, resulting in broken grids that affect the power and reliability of the photovoltaic module.

[0098] After the high-temperature welding is completed, the welding tooling is removed, and the high-temperature welded battery strings are arranged into the battery string arrangement structure in the photovoltaic module, and laminated. The temperature during the lamination process is used to perform low-temperature welding on the low-temperature welding strip 6, so that the low-temperature welding strip 6 and the fine grid 3 are alloyed to form a good contact.

[0099] Optionally, during the lamination process, the lamination temperature may be 135-160° C. As an example, the lamination temperature may be 135° C., 140° C., 150° C., or 160° C.

[0100] In an optional embodiment, step N1 further includes: fixing the low-temperature soldering tape 6 by gluing.

[0101] Since the high temperature welding strip 2 needs to be welded first during the welding process, and the welding temperatures of the low temperature welding strip 6 and the high temperature welding strip 2 are different, in order to prevent the low temperature welding strip 6 from moving during the high temperature welding process, the low temperature welding strip 6 can be fixed on the battery cell by gluing.

[0102] It is understandable that the fixing method of the low-temperature soldering tape 6 is not limited to the gluing method, and any method that can achieve the fixing of the low-temperature soldering tape 6 and does not affect the preparation of the photovoltaic module can be used, and no specific limitation is made here.

[0103] Furthermore, the gluing method may include two methods: glue point gluing and tape gluing.

[0104] The glue point bonding method may use an acrylic thermosetting adhesive, but is not limited thereto. The light transmittance of the thermosetting adhesive is greater than or equal to 90%, the height of the formed glue point 7 is less than 150 μm, and the area of ​​the glue point 7 is less than 1 mm 2 , the number of glue dots 7 in each low-temperature solder strip 6 of each cell is 3-10, and the curing temperature is 80-120°C. The gluing methods include but are not limited to printing and dispensing. As an example, the transmittance of the thermosetting glue in the glue point gluing method can be 90%, 92% or 95%, etc., the height of the glue dots 7 formed by the thermosetting glue can be 150μm, 140μm, 120μm or 100μm, etc., and the area of ​​the glue dots 7 can be 1mm 2 , 0.8mm 2 , 0.5mm 2 or 0.3mm 2 The number of glue dots 7 in each low-temperature solder strip 6 of each battery cell can be 3, 5, 8 or 10, and the curing temperature can be 80°C, 90°C, 100°C or 120°C.

[0105] In the tape gluing method, a self-adhesive tape 8 may be used. The light transmittance of the tape 8 is greater than or equal to 90%, the width may be 1-5 mm, the thickness may be 10-50 μm, and the length should be consistent with the length of the low-temperature solder tape 6 laid in one battery cell. As an example, the light transmittance of the tape 8 in the tape gluing method may be 90%, 92% or 95%, the width may be 1 mm, 2 mm, 3 mm or 5 mm, the thickness may be 10 μm, 20 μm, 30 μm or 50 μm, etc.

[0106] The following two examples illustrate the method of laying out battery strings using glue point gluing and tape gluing.

[0107] Example 1: In step A1, the battery string is laid out by using glue point gluing method.

[0108] like Fig.12As shown, glue dots 7 are printed between adjacent first main grids 1 on the upper and lower surfaces of the cell, so that the positions of the glue dots 7 correspond to the positions of the low-temperature solder strips 6 to be laid. When printing the glue dots 7, the glue dots 7 on the lower surface of the cell can be printed first, and then the glue dots 7 on the upper surface of the cell, so that when the solder strips are subsequently laid on the surface of the cell, there is no need to flip the cell again. Lay the high-temperature solder strips 2 and the low-temperature solder strips 6 on the stringing machine, refer to Fig.13 , place the current cell with glue dots 7 printed on it on the laid high-temperature welding tape 2 and low-temperature welding tape 6, so that the high-temperature welding tape 2 corresponds to the first main grid 1 on the lower surface of the current cell, and the low-temperature welding tape 6 corresponds to the position between two adjacent first main grids 1 on the lower surface, and the low-temperature welding tape 6 is fixed by the glue dots 7 on the current cell. Lay the high-temperature welding tape 2 and the low-temperature welding tape 6 at the corresponding position on the upper surface of the current cell with glue dots 7 printed on it. Lay another cell with glue dots 7 printed on it, and make each first main grid 1 of the other cell correspond to each first main grid 1 of the above-mentioned current cell, so that the two cells are placed correspondingly, and the other ends of the high-temperature welding tape 2 and the low-temperature welding tape 6 on the upper surface of the above-mentioned current cell are located on the lower surface of the above-mentioned other cell, and the low-temperature welding tape 6 is fixed by the glue dots 7 on the other cell. Take the above-mentioned other cell as the current cell, and step in a loop until a cell string is laid out.

[0109] Example 2: In step A1, the battery string is laid out by adhesive tape.

[0110] like Fig.14 As shown, the tape 8 is laid on the stringer, and then the high-temperature soldering tape 2 and the low-temperature soldering tape 6 are laid, so that the low-temperature soldering tape 6 is located above the tape 8, refer to Fig.15, place the current cell on the laid high temperature welding tape 2 and low temperature welding tape 6, so that the high temperature welding tape 2 corresponds to the first main grid 1 of the current cell, and the low temperature welding tape 6 corresponds to the position between two adjacent first main grids 1, and the low temperature welding tape 6 is fixed to the lower surface of the current cell by the adhesive tape 8 laid below the low temperature welding tape 6. Lay the adhesive tape 8 next to the current cell, and lay the high temperature welding tape 2 and low temperature welding tape 6 at the corresponding position on the upper surface of the current cell, one end of the high temperature welding tape 2 and the low temperature welding tape 6 is located on the upper surface of the current cell, the other end of the high temperature welding tape 2 is located next to the current cell, and the other end of the low temperature welding tape 6 is located on the adhesive tape 8 laid next to the current cell. Lay the adhesive tape 8 on the low temperature welding tape 6 on the upper surface of the current cell, so that one end of the low temperature welding tape 6 is fixed to the upper surface of the current cell by the adhesive tape 8. Lay out another cell, and make each first main grid 1 of the other cell correspond to each first main grid 1 of the above current cell, so that the two cells are placed correspondingly, and the other ends of the high temperature welding belt 2 and the low temperature welding belt 6 on the upper surface of the above current cell are located on the lower surface of the above other cell, and the other end of the low temperature welding belt 6 is fixed to the lower surface of the other cell by using the adhesive tape 8 below the other end of the low temperature welding belt 6. Take the above other cell as the current cell, and step in a loop until a cell string is laid out.

[0111] According to the preparation method of the photovoltaic module of the embodiment of the present invention, by laying the low-temperature welding tape and the high-temperature welding tape simultaneously in the battery cell before high-temperature welding to form a battery string, there is no need to add a low-temperature welding process in the process of preparing the above-mentioned battery string into a photovoltaic module, and the low-temperature welding tape can be directly low-temperature welded by the temperature of the lamination process. At the same time, the laid battery string is fixed by the welding tool, which can avoid the displacement of the high-temperature welding tape and the low-temperature welding tape during the high-temperature welding process, and can also provide thermal insulation protection for the low-temperature welding tape to avoid the problem of broken grid caused by tinning of the low-temperature welding tape during the high-temperature welding process.

[0112] In addition, the low-temperature soldering tape is fixed by gluing, which further ensures the stability of the low-temperature soldering tape and prevents the low-temperature soldering tape from shifting.

[0113] Fig.16 is a schematic structural diagram of a pressure discharge component according to an embodiment of the present invention; Fig.17 Schematic diagram of the structure of the welding support component according to an embodiment of the present invention. Fig.16 and Fig.17 As shown, an embodiment of the present invention provides a welding tool for a photovoltaic module, which is applied to any of the above-mentioned methods for preparing a photovoltaic module, and includes: a pressure-discharging component 9 and a welding support component 10 .

[0114] like Fig.16As shown, the above-mentioned pressure-discharging component 9 includes a connecting portion 901, a plurality of pressure blocks 902 and a plurality of pressure needles 903, wherein the plurality of pressure needles 903 are arranged at intervals on the above-mentioned connecting portion 901, and the plurality of pressure blocks 902 are arranged on the above-mentioned connecting portion 901 and located between adjacent pressure needles 903.

[0115] The connecting part 901 includes a first connecting part 9011 and a second connecting part 9012, which are vertically arranged. The pressing needle part 903 is arranged at intervals on the first connecting part 9011, and the pressing block part 902 is arranged on the second connecting part 9012, and the pressing block part 902 and the second connecting part 9012 are located between adjacent pressing needle parts 903.

[0116] In addition, the pressure-discharging component 9 further includes a frame 904, which is connected to the connecting portion 901 and is used to support and fix the connecting portion 901. Specifically, the frame 904 is connected to the end of the first connecting portion 9011.

[0117] like Fig.17 As shown, the welding support component 10 comprises a heating device 1001 , a bottom plate 1002 and a heat insulating interlayer 1003 spaced apart on the bottom plate 1002 ; the heating device 1001 is connected to the bottom plate 1002 .

[0118] There may be a plurality of heating devices 1001 , which are respectively disposed at both ends of the bottom plate 1002 to provide heat for the bottom plate 1002 during high temperature welding.

[0119] During the use of the above-mentioned welding tooling, the above-mentioned pressure-discharging component 9 is placed above the laid battery string; the above-mentioned welding support component 10 is used to support the laid battery string; wherein the above-mentioned pressure needle part 903 corresponds to the high-temperature welding strip 2 on the upper surface of the laid battery string; the above-mentioned pressure block part 902 corresponds to the low-temperature welding strip 6 on the upper surface of the laid battery string; the above-mentioned thermal insulation interlayer 1003 corresponds to the low-temperature welding strip 6 on the lower surface of the laid battery string; the above-mentioned heating device 1001 provides heat for the above-mentioned bottom plate 1002 to perform high-temperature welding on the high-temperature welding strip 2 in the laid battery string.

[0120] It should be noted that, in the process of laying the battery string, the welding tool and the string welding machine cooperate with each other, the welding support component 10 is placed under the welding light box on the string welding machine table, and the welding support component 10 is used as a table for laying the battery string. After the battery string is laid, the pressure strip component 9 is placed on top of the laid battery string. After the welding light box is turned on, infrared rays are emitted, and the heating device 1001 of the welding support component 10 is turned on to provide heat for the bottom plate 1002, and cooperate with the light box to perform high-temperature welding on the high-temperature welding strip 2. The heat-insulating interlayer 1003 set in the bottom plate 1002 can prevent heat from being transferred to the position of the low-temperature welding strip 6, thereby avoiding the problem of broken grid caused by alloying the low-temperature welding strip 6 with the fine grid 3 during high-temperature welding.

[0121] In an optional embodiment, if Fig.18 As shown, the above-mentioned pressing needle part 903 includes an elastic piece 9031 and a pressing needle body 9032; the pressing needle body 9032 is elastically connected to the connecting part 901 through the above-mentioned elastic piece 9031; during the use of the above-mentioned pressing needle part 903, the position of each pressing needle part 903 corresponds to the position of the high-temperature welding strip 2 in the laid battery string, and the above-mentioned pressing needle body 9032 applies pressure to the above-mentioned high-temperature welding strip 2. Under the action of pressure, the above-mentioned elastic piece 9031 contracts, driving the above-mentioned pressing needle body 9032 to move in the direction away from the battery string, wherein the contraction direction of the above-mentioned elastic piece 9031 is the same as the contraction direction of the above-mentioned battery string.

[0122] One end of the pressing needle body 9032 is connected to the elastic member 9031 , and the other end can be set as a truncated cone structure to increase the contact area between the bottom of the pressing needle body 9032 and the high-temperature welding strip 2 during the use of the pressing needle part 903 , thereby strengthening the fixation of the high-temperature welding strip 2 .

[0123] The elastic member 9031 includes a clip 90311 and a spring 90312. The pressure needle body 9032 penetrates the clip 90311 and is engaged with the first connecting portion 9011 through the clip 90311. A cavity is provided between the clip 90311 and the connecting portion 901, and the spring 90312 is provided in the cavity, and one end of the spring 90312 is fixedly connected to the pressure needle body 9032. When the pressure-discharging component 9 is placed above the laid battery string, the pressure-discharging component 9 applies pressure to the laid battery string, and the pressure needle body 9032 corresponds to the high-temperature welding strip 2 and applies pressure to the high-temperature welding strip 2. Under the reaction force of the high-temperature welding strip 2, the spring 90312 contracts, driving the pressure needle body 9032 to move away from the battery string. Under the limitation of the retaining spring 90311, the pressure needle body 9032 will not fall off from the cavity, thereby preventing the high-temperature welding strip 2 from shifting during the high-temperature welding process and forming a more reliable contact between the high-temperature welding strip 2 and the first main grid 1.

[0124] In an optional embodiment, if Fig.19As shown, the pressing block portion 902 includes a reflective layer 9021 located above the connecting portion 901 and a heat insulating pad 9022 located below the connecting portion 901, wherein the reflective layer 9021 and the heat insulating pad 9022 are arranged correspondingly.

[0125] Specifically, the pressing block part 902 includes a reflective layer 9021 located above the second connecting part 9012 and a heat insulating pad 9022 located below the second connecting part 9012.

[0126] The reflective layer 9021 is a smooth metal coating. When high temperature welding is performed by infrared welding, the reflective layer 9021 is used to reflect infrared light to prevent the infrared light from irradiating the low temperature welding strip 6 and alloying the low temperature welding strip 6 with the fine grid 3 during high temperature welding.

[0127] During the use of the pressing block 902, the heat insulating pad 9022 can apply downward pressure to better fix the low temperature welding strip 6 in the laid battery string, and prevent the low temperature welding strip 6 from shifting during high temperature welding. At the same time, the heat insulating pad 9022 can further reduce the conduction of heat during high temperature welding, and prevent the low temperature welding strip 6 from tinning during high temperature welding.

[0128] Optionally, the thermal insulation block 9022 may be made of a thermal insulation material having a thermal conductivity of less than 0.174 W / (m·K); the width of the thermal insulation block 9022 may be 1-5 mm. As an example, the thermal insulation block 9022 may be made of a thermal insulation material having a thermal conductivity of 0.170 W / (m·K), 0.100 W / (m·K), 0.050 W / (m·K) or 0.020 W / (m·K); the width of the thermal insulation block 9022 may be 1 mm, 2 mm, 3 mm or 5 mm. As another example, the thermal insulation block 9022 may be made of a thermal insulation material such as silica aerogel, nano thermal insulation board or high silica fiber felt, but is not limited thereto.

[0129] When the low-temperature solder strip 6 is fixed by gluing with tape, the end of the thermal insulation pad 9022 away from the second connecting portion 9012 can be a flat surface, so that when the pressing block portion 902 applies pressure, uniform pressure can be applied to the tape 8, so that the tape 8 can fix the low-temperature solder strip 6 more firmly on the surface of the battery string.

[0130] Furthermore, if Fig. 20 As shown, the above-mentioned insulation pad 9022 is provided with grooves 90221 on one side away from the above-mentioned connecting part 901; when the above-mentioned low-temperature solder strip 6 is fixed by gluing, the above-mentioned grooves 90221 correspond to the above-mentioned glue dots 7, so as to accommodate the glue dots 7 when the above-mentioned pressing block part 902 applies pressure to the above-mentioned low-temperature solder strip 6, so as to prevent the glue dots 7 from being damaged during the use of the pressing block part 902.

[0131] Furthermore, the heat insulating pad 9022 of the pressing block part 902 is detachably connected to the second connecting part 9012, so that the heat insulating pad 9022 with corresponding intervals can be replaced according to the glue points 7 with different intervals, further increasing the practicality of the pressure discharge component 9.

[0132] According to the welding fixture of the photovoltaic module of the embodiment of the present invention, the laid battery string can be fixed by the mutual cooperation of the pressure-discharging component and the welding support component, so as to prevent the high-temperature welding strip and the low-temperature welding strip from shifting during the high-temperature welding process. In addition, by providing a pressure block part containing a heat-insulating pad in the pressure-discharging component and providing a heat-insulating interlayer in the welding support component, the low-temperature welding strip can be heat-insulated and protected during the high-temperature welding process, so as to prevent the low-temperature welding strip from tinning and causing the grid to break during the high-temperature welding process.

[0133] The photovoltaic module and the method for preparing the photovoltaic module provided by the present invention are further described below based on specific embodiments. The following description is only used to explain the relevant inventions of this application and is not intended to limit the present invention.

[0134] Use Figure 4 For the cell of the structure shown, 20 welding strips can be laid on the surface of each cell, including 15 high-temperature welding strips 2 and 5 low-temperature welding strips 6. A high-temperature welding strip is laid on the first main grid 1 on the lower surface of the first cell, and a low-temperature welding strip 6 is laid between the first main grids 1. The second cell is placed corresponding to the first cell, so that each first main grid 1 in the second cell is aligned with each first main grid 1 in the first cell, and the other end of the high-temperature welding strip 2 laid on the lower surface of the first cell is laid on the first main grid 1 on the upper surface of the second cell, and the other end of the low-temperature welding strip 6 laid on the upper surface of the first cell is laid between the first main grids 1 on the upper surface of the second cell, and the process is repeated until a cell string is laid. The low-temperature welding strips 6 in the cell string are fixed by adhesive tape.

[0135] The high temperature solder strip 2 may be made of Sn60Pb40 with a diameter of 0.2 mm and a melting point of 183°C; the low temperature solder strip 6 may be made of Sn32Pb42Bi26 with a diameter of 0.2 mm and a melting point of 135°C.

[0136] In the string welding machine, the following Fig.16 The pressure member 9 shown and Fig.17 The welding support component 10 shown fixes the laid battery string, and the high temperature welding strip 2 in the laid battery string is welded at high temperature by emitting infrared rays from the welding light box and the heat provided by the welding support component 10, so that the high temperature welding strip 2 forms a good contact with the first main grid 1. The welding temperature of the welding light box is 280°C, and the temperature of the welding support component is 100°C.

[0137] Specifically, the pressure needle part 903 in the pressure discharge part 9 applies pressure to the high temperature welding strip 2 in the laid battery string, the pressure block part 902 applies pressure to the low temperature welding strip 6 in the laid battery string, the welding support part 10 provides support for the laid battery string, and the heat insulation interlayer 1003 corresponds to the low temperature welding strip 6. When the high temperature welding strip 2 in the laid battery string is subjected to high temperature welding by the infrared rays emitted by the welding light box and the heat provided by the welding support part 10, the heat is transferred to the position of the high temperature welding strip 2, so that the high temperature welding strip 2 is tinned and alloyed with the first main grid 1, and a stable connection is formed between the high temperature welding strip 2 and the first main grid 1; the reflective layer 9021 in the pressure block part 902 can reflect the infrared rays emitted by the welding light box, and the heat insulation pad 9022 in the pressure block part 902 and the heat insulation interlayer 1003 in the welding support part 10 can prevent heat from being transferred to the position of the low temperature welding strip 6, thereby avoiding the problem of the low temperature welding strip 6 being tinned and alloyed with the fine grid 3 during the high temperature welding process, resulting in the problem of broken grid.

[0138] It should be noted that both the high-temperature solder strip 2 and the low-temperature solder strip 6 have a tin-plated layer on their surfaces. During the soldering process, the tin-plated layer melts and turns into liquid tin, which is called tinning. The liquid tin can alloy with the gate line.

[0139] After high-temperature welding, the defects in the battery string after high-temperature welding were identified through electroluminescent (EL) testing. It was found that the battery string performed well after the above process, no abnormal hidden cracks were observed, and the low-temperature welding strip 6 did not undergo tinning, and there was no broken grid at the fine grid. After being fixed with tape, the low-temperature welding strip 6 did not shift.

[0140] The battery strings that have been welded at high temperature are stacked. The weight of the adhesive film used in the stacking process is 360g / m 2 Compared with the conventional photovoltaic modules of 16BB, the weight of the adhesive film used in the preparation process of the photovoltaic module preparation method of this embodiment is reduced, thereby reducing the consumption of the adhesive film.

[0141] The stacked battery string is laminated at a lamination temperature of 145°C. During the lamination process, the low-temperature solder strip 6 can be tinned by the lamination temperature, so that the low-temperature solder strip 6 and the fine grid 3 are alloyed to complete the low-temperature welding. Due to the high melting point of the high-temperature solder strip, the high-temperature solder strip will not have the problem of secondary tinning during the lamination process, avoiding the problem of loose connection between the high-temperature solder strip 2 and the first main grid 1 due to secondary tinning. After lamination, the EL test found that the laminated battery string performed well.

[0142] After steps such as framing, photovoltaic modules are obtained.

[0143] After testing, the power of the photovoltaic module of this embodiment is basically the same as that of the conventional photovoltaic module of 16BB. However, compared with the conventional photovoltaic module of 16BB, the thickness of the cell of the photovoltaic module of this embodiment is reduced by 20μm, each photovoltaic module can save 40mg of silver paste, the diameter of the welding belt is reduced by 0.06mm, and the weight of the adhesive film is reduced by 60g / m 2 , the cost can be reduced by 0.2 cents / W. And the photovoltaic module of this embodiment is tested by TC-400 according to the IEC61215 standard. After the test, the power loss is less than 2%, which means that the photovoltaic module of this embodiment can still maintain a high power output capacity after a relatively severe temperature change test. The structure and manufacturing process of the photovoltaic module have good stability and can achieve long-term stable outdoor power generation.

[0144] In summary, the embodiments of the present invention provide the following technical solutions:

[0145] Technical solution 1, a photovoltaic module, comprising: one or more battery strings, wherein:

[0146] The battery string includes a plurality of battery cells and a plurality of high-temperature welding strips 2 and a plurality of low-temperature welding strips 6 connecting the battery cells in series;

[0147] Each of the battery cells is provided with a plurality of first main grids 1;

[0148] Each of the high-temperature welding strips 2 is connected in series with two corresponding first main grids 1 of two adjacent battery cells;

[0149] Each of the low-temperature welding strips 6 is disposed between two adjacent first main grids 1 on the battery cell, and connects two adjacent battery cells in series.

[0150] Technical solution 2: The photovoltaic module according to technical solution 1,

[0151] The number of the high-temperature welding strips 2 on the surface of the battery string is greater than or equal to the number of the low-temperature welding strips 6 .

[0152] Technical solution 3: The photovoltaic module according to technical solution 1,

[0153] The cell further comprises: a fine grid welding contact point 301 is arranged between two adjacent first main grids 1;

[0154] The low-temperature welding strip 6 is electrically connected to the fine grid welding contact point 301 between two adjacent first main grids 1;

[0155] or,

[0156] The cell further comprises: a plurality of segmented main grids 4 are arranged between two adjacent first main grids 1;

[0157] The low temperature welding strip 6 is arranged along the plurality of segmented main grids 4 and is electrically connected to the plurality of segmented main grids 4;

[0158] or,

[0159] The cell further includes: a second main grid 5 is arranged between two adjacent first main grids 1, wherein the width of the second main grid 5 is smaller than the width of the first main grid 1;

[0160] The low-temperature welding tape 6 is arranged along the second main grid 5 and is electrically connected to the second main grid 5;

[0161] and / or,

[0162] The fine grid 3 included in the cell sheet includes first fine grid segments 302 and second fine grid segments 303 arranged alternately, wherein the width of the second fine grid segment 303 is greater than the width of the first fine grid segment 302;

[0163] The first main gate 1 is electrically connected to the first fine gate segment 302;

[0164] The low-temperature welding strip 6 is electrically connected to the second fine grid segment 303 .

[0165] Technical solution 4: The photovoltaic module according to technical solution 3,

[0166] In the case where the cell comprises a fine grid welding contact point 301 disposed between two adjacent first main grids 1, the total area of ​​the fine grid welding contact points 301 disposed between the two adjacent first main grids 1 is less than 0.5 mm2;

[0167] or,

[0168] In the case where the battery cell includes the segmented main grid 4, the length of each segmented main grid 4 is 2-50 mm;

[0169] or,

[0170] In the case where the cell includes the second main grid 5 , the width of each second main grid 5 is 10-20 μm;

[0171] and / or,

[0172] When the fine grid 3 of the cell includes the first fine grid segment 302 , the width of the second fine grid segment is 10-80 μm.

[0173] Technical Solution 5: According to the photovoltaic module described in any one of Technical Solutions 1-4, the thickness of the cell is 80-140 μm.

[0174] Technical solution 6: A method for preparing a photovoltaic module, comprising:

[0175] Repeat the following steps N1 to N2 until the battery string is laid out:

[0176] N1. Lay one end of the high-temperature welding tape on the first main grid of the current battery cell; lay one end of the low-temperature welding tape between two adjacent first main grids of the current battery cell, and fix the low-temperature welding tape;

[0177] N2, laying another battery cell on the other end of the high-temperature welding strip and the other end of the low-temperature welding strip, and taking the other battery cell as the current battery cell, and executing N1;

[0178] The laid battery string is fixed by using welding tools, and the high temperature welding strips in the laid battery string are subjected to high temperature welding;

[0179] The welding tool is removed, and the battery string that has been subjected to high-temperature welding is laminated. During the lamination process, the low-temperature welding of the low-temperature welding strip is performed to obtain a battery string that has been welded;

[0180] Assemble multiple welded cell strings into photovoltaic modules.

[0181] Technical solution 7: According to the method for preparing a photovoltaic module according to technical solution 6, step N1 comprises:

[0182] The low-temperature soldering tape is fixed by gluing.

[0183] Technical solution 8, a welding tool for a photovoltaic module, applied to the method for preparing a photovoltaic module as described in any one of technical solutions 6 to 7, comprising: a pressure discharge component 9 and a welding support component 10;

[0184] The pressure-discharging component 9 includes a connecting portion 901, a plurality of pressure blocks 902 and a plurality of pressure needles 903, wherein the plurality of pressure needles 903 are arranged at intervals on the connecting portion 901, and the plurality of pressure blocks 902 are arranged on the connecting portion 901 and located between adjacent pressure needles 903;

[0185] The welding support component 10 comprises a heating device 1001, a bottom plate 1002 and a heat insulating interlayer 1003 arranged at intervals on the bottom plate 1002; the heating device 1001 is connected to the bottom plate 1002;

[0186] During the use of the welding tool, the pressure-discharging component 9 is placed above the laid battery string; the welding support component 10 is used to support the laid battery string; wherein the pressure needle part 903 corresponds to the high-temperature welding strip 2 on the upper surface of the laid battery string; the pressure block part 902 corresponds to the low-temperature welding strip 6 on the upper surface of the laid battery string; the thermal insulation interlayer 1003 corresponds to the low-temperature welding strip 6 on the lower surface of the laid battery string; the heating device 1001 provides heat to the bottom plate 1002 to perform high-temperature welding on the high-temperature welding strip 2 in the laid battery string.

[0187] Technical solution 9, according to the welding tool of the photovoltaic module described in technical solution 8, the pressing needle part 903 includes an elastic member 9031 and a pressing needle body 9032;

[0188] The pressing needle body 9032 is elastically connected to the connecting portion 901 through the elastic member 9031;

[0189] During the use of the pressing needle part 903, the pressing needle body 9032 applies pressure to the high-temperature welding strip 2. Under the action of pressure, the elastic member 9031 contracts, driving the pressing needle body 9032 to move away from the battery string, wherein the contraction direction of the elastic member 9031 is the same as the contraction direction of the battery string.

[0190] Technical Solution 10. According to the welding tooling of the photovoltaic module described in Technical Solution 8, the pressing block part 902 includes a reflective layer 9021 located above the connecting part 901 and an insulating pad 9022 located below the connecting part 901, wherein the reflective layer 9021 and the insulating pad 9022 are arranged correspondingly.

[0191] Technical solution 11. A welding tool for photovoltaic modules according to technical solution 10,

[0192] A groove 90221 is provided at intervals on a side of the heat-insulating pad 9022 away from the connecting portion 901;

[0193] When the low-temperature solder strip 6 is fixed by gluing with glue dots, the groove 90221 corresponds to the glue dots 7 to accommodate the glue dots 7 when the pressing block portion 902 applies pressure to the low-temperature solder strip 6 .

[0194] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A photovoltaic module, characterized in that: include: One or more battery strings, wherein The battery string comprises a plurality of battery cells and a plurality of high-temperature welding strips (2) and a plurality of low-temperature welding strips (6) connecting the battery cells in series; Each of the battery cells is provided with a plurality of first main grids (1); Each of the high-temperature welding strips (2) is connected in series to two corresponding first main grids (1) of two adjacent battery cells; Each of the low-temperature welding strips (6) is arranged between two adjacent first main grids (1) on the battery cell, and connects two adjacent battery cells in series.

2. The photovoltaic module according to claim 1, characterized in that: The number of high-temperature welding strips (2) on the surface of the battery string is greater than or equal to the number of low-temperature welding strips (6).

3. The photovoltaic module according to claim 1, characterized in that: The battery cell further comprises: a fine grid welding contact point (301) is arranged between two adjacent first main grids (1); The low-temperature welding strip (6) is electrically connected to the fine grid welding contact point (301) between two adjacent first main grids (1); or, The cell further comprises: a plurality of segmented main grids (4) arranged between two adjacent first main grids (1); The low-temperature welding strip (6) is arranged along the plurality of segmented main grids (4) and is electrically connected to the plurality of segmented main grids (4); or, The cell further comprises: a second main grid (5) arranged between two adjacent first main grids (1), wherein the width of the second main grid (5) is smaller than the width of the first main grid (1); The low-temperature welding strip (6) is arranged along the second main grid (5) and is electrically connected to the second main grid (5); and / or, The fine grid (3) included in the cell sheet comprises first fine grid segments (302) and second fine grid segments (303) that are arranged alternately, wherein the width of the second fine grid segment (303) is greater than the width of the first fine grid segment (302); The first main grid (1) is electrically connected to the first fine grid segment (302); The low-temperature welding strip (6) is electrically connected to the second fine grid segment (303).

4. The photovoltaic module according to claim 3, characterized in that: In the case where the cell comprises a fine grid welding contact point (301) arranged between two adjacent first main grids (1), the total area of ​​the fine grid welding contact points (301) arranged between the two adjacent first main grids (1) is less than 0.5 mm 2 ; or, When the battery cell comprises the segmented main grid (4), the length of each segmented main grid (4) is 2-50 mm; or, When the cell comprises the second main grid (5), the width of each second main grid (5) is 10-20 μm; and / or, When the fine grid (3) of the cell sheet comprises the first fine grid segment (302), the width of the second fine grid segment is 10-80 μm.

5. The photovoltaic module according to any one of claims 1 to 4, characterized in that: The thickness of the battery cell is 80-140 μm.

6. A method for preparing a photovoltaic module, characterized in that: include: Repeat the following steps N1 to N2 until the battery string is laid out: N1. Lay one end of the high-temperature welding tape on the first main grid of the current battery cell; lay one end of the low-temperature welding tape between two adjacent first main grids of the current battery cell, and fix the low-temperature welding tape; N2, laying another battery cell on the other end of the high-temperature welding strip and the other end of the low-temperature welding strip, and taking the other battery cell as the current battery cell, and executing N1; The laid battery string is fixed by using welding tools, and the high temperature welding strips in the laid battery string are subjected to high temperature welding; The welding tool is removed, and the battery string that has been subjected to high-temperature welding is laminated. During the lamination process, the low-temperature welding of the low-temperature welding strip is performed to obtain a battery string that has been welded; Assemble multiple welded cell strings into photovoltaic modules.

7. The method for preparing a photovoltaic module according to claim 6, characterized in that: Step N1 includes: The low-temperature soldering tape is fixed by gluing.

8. A welding tool for photovoltaic modules, applied to the method for preparing photovoltaic modules according to any one of claims 6 to 7, characterized in that: include: A pressure-discharging component (9) and a welding support component (10); The pressure-discharging component (9) comprises a connecting portion (901), a plurality of pressure block portions (902) and a plurality of pressure needle portions (903), wherein the plurality of pressure needle portions (903) are arranged at intervals on the connecting portion (901), and the plurality of pressure block portions (902) are arranged on the connecting portion (901) and are located between adjacent pressure needle portions (903); The welding support component (10) comprises a heating device (1001), a bottom plate (1002), and a heat-insulating interlayer (1003) arranged at intervals on the bottom plate (1002); the heating device (1001) is connected to the bottom plate (1002); During use of the welding tool, the pressure-discharging component (9) is placed above the laid battery string; the welding support component (10) is used to support the laid battery string; wherein the pressure needle portion (903) corresponds to the high-temperature welding strip (2) on the upper surface of the laid battery string; the pressure block portion (902) corresponds to the low-temperature welding strip (6) on the upper surface of the laid battery string; the heat-insulating interlayer (1003) corresponds to the low-temperature welding strip (6) on the lower surface of the laid battery string; and the heating device (1001) provides heat to the bottom plate (1002) to perform high-temperature welding on the high-temperature welding strip (2) in the laid battery string.

9. The welding tool for photovoltaic modules according to claim 8, characterized in that: The pressing needle part (903) comprises an elastic member (9031) and a pressing needle body (9032); The pressing needle body (9032) is elastically connected to the connecting portion (901) via the elastic member (9031); When the pressing needle part (903) is in use, the pressing needle body (9032) applies pressure to the high-temperature welding strip (2), and under the action of the pressure, the elastic member (9031) contracts, driving the pressing needle body (9032) to move in a direction away from the battery string, wherein the contraction direction of the elastic member (9031) is the same as the contraction direction of the battery string.

10. The photovoltaic module welding tool according to claim 8, characterized in that: The pressing block portion (902) comprises a reflective layer (9021) located above the connecting portion (901) and a heat-insulating pad (9022) located below the connecting portion (901), wherein the reflective layer (9021) and the heat-insulating pad (9022) are arranged correspondingly.

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