Back contact cell string and photovoltaic module

Abstract

The utility model discloses a back contact cell string and a photovoltaic assembly, the back contact cell string comprises a plurality of cells and a plurality of solder strips, the backlight surface of each cell is provided with a plurality of frame lines and a plurality of fine grid lines, the frame lines are distributed along a second direction, and the fine grid lines are distributed along a second direction. The plurality of rows of fine grid lines are distributed at intervals along a second direction, each row of fine grid lines are distributed at intervals along a first direction, a backlight surface of the battery piece comprises a plurality of welding areas which are distributed perpendicular to the fine grid lines, part of the fine grid lines are distributed at two sides of the welding areas at intervals, and part of the fine grid lines penetrate through the welding areas and are connected with the frame lines; a plurality of bonding glue layers are arranged on each welding area, a plurality of insulating glue layers are arranged on the welding area adjacent to the frame line, the bonding glue layers are positioned between two adjacent fine grid lines in the same row, and the insulating glue layers cover the fine grid lines. According to the utility model, the welding tension between the welding strip and the battery piece can be effectively improved, and the current collection capability can be improved through the design of the fine grid lines.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar cells, and in particular relates to a back-contact cell string and a photovoltaic component. Background Art

[0002] BC (Back Contact) battery is the full name of the back contact battery. It sets the PN junction and positive and negative electrodes all on the back of the battery, which can maximize the light-receiving area of the battery cell and reduce optical loss energy, thereby greatly improving the photoelectric conversion efficiency of the battery cell.

[0003] 0BB (Zero Busbar) technology is an innovative process that eliminates the busbar in traditional battery cells during battery manufacturing. By using solder ribbons to directly connect to the fine grid lines on the battery cells, the amount of silver paste used can be reduced, thereby reducing process costs.

[0004] Existing busbarless BC batteries usually use a glue dispensing process to fix the welding ribbon to multiple battery cells, and then weld the multiple battery cells into a battery string. The structural design of the glue dispensing point often affects the current collection capacity of the fine grid line.

[0005] Therefore, in order to solve the above technical problems, it is necessary to provide a back-contact cell string and photovoltaic module. Utility Model Content

[0006] The purpose of the present invention is to provide a back-contact cell string and photovoltaic module to increase the welding tension between the welding ribbon and the cell sheet and to improve the current collection capacity of the cell string and the module.

[0007] In order to achieve the above-mentioned purpose, the technical solution provided by one embodiment of the present invention is as follows:

[0008] A back-contact battery string, the back-contact battery string includes multiple battery cells and multiple welding strips, the backlight surface of the battery cell is provided with multiple frame lines and multiple fine grid lines, the frame lines are distributed along a second direction, multiple rows of fine grid lines are spaced apart along the second direction and each row of fine grid lines is spaced apart along the first direction, the backlight surface of the battery cell includes multiple welding areas distributed perpendicular to the fine grid lines, some of the fine grid lines are spaced apart on both sides of the welding area, some of the fine grid lines are arranged through the welding area and are connected to the frame lines, each of the welding areas is provided with multiple adhesive layers, and the welding area adjacent to the frame line is provided with multiple insulating layers, the adhesive layer is located between two adjacent fine grid lines in the same row, the insulating layer covers the fine grid line, the welding strip is located in the welding area and is fixed to the backlight surface of the battery cell through the adhesive layer or the adhesive layer and the insulating layer.

[0009] In one embodiment, in the welding area adjacent to the frame line, the welding ribbon is fixed to the backlight surface of the battery cell through an adhesive layer and an insulating layer, and in the remaining welding areas, the welding ribbon is fixed to the backlight surface of the battery cell through an adhesive layer.

[0010] In one embodiment, the fine gate lines further include reinforcement lines, the reinforcement lines are at least partially located in the welding region, and the line width of the reinforcement lines is greater than the line width of the fine gate lines.

[0011] In one embodiment, in the welding area adjacent to the frame line, the height of the reinforcement line close to the insulating adhesive layer is greater than the height of the reinforcement line away from the insulating adhesive layer.

[0012] In one embodiment, in the welding area adjacent to the frame line, the upper surface of the reinforcement line close to the insulating adhesive layer is flat, or is inclined or curved in a direction away from the insulating adhesive layer toward the backlight surface of the battery cell.

[0013] In one embodiment, a first connecting line is provided between at least two reinforcing lines adjacent to the insulating adhesive layer in a welding area adjacent to the frame line.

[0014] In one embodiment, in the welding area adjacent to the frame line, the reinforcing line adjacent to the insulating layer is disconnected from the fine grid lines in its row, and a second connecting line is provided between the fine grid lines in the row where the reinforcing line is located and the fine grid lines away from the insulating layer.

[0015] In one embodiment, the border line includes a first border line and a second border line arranged opposite to each other along a first direction, and the fine gate line includes multiple rows of first fine gate lines and second fine gate lines alternately distributed along a second direction, the first border line is connected to the first fine gate line, and the second border line is connected to the second fine gate line.

[0016] In one embodiment, the welding area includes a first welding area and a second welding area alternately distributed along a first direction;

[0017] Some of the first thin grid lines are spaced apart and distributed on both sides of the first welding area, and some of the first thin grid lines pass through the first welding area and are connected to the first border line;

[0018] Some of the second thin gate lines are spaced apart and distributed on both sides of the second welding area, and some of the second thin gate lines pass through the second welding area and are connected to the second border line.

[0019] In one embodiment, the welding strips include first welding strips and second welding strips alternately distributed along a first direction;

[0020] A plurality of first adhesive layers are provided on each first welding area, a plurality of first insulating layers are provided on the first welding area adjacent to the first border line, the first adhesive layer is located between two adjacent first fine grid lines in the same row, the first insulating layer covers the first fine grid lines, the first welding ribbon is located in the first welding area and is fixed to the backlight surface of the solar cell by the first adhesive layer or the first adhesive layer and the first insulating layer;

[0021] Multiple second adhesive layers are provided on each second welding area, and multiple second insulating layers are provided on the second welding area adjacent to the second border line. The second adhesive layer is located between two adjacent second fine grid lines in the same row, and the second insulating layer covers the second fine grid lines. The second welding strip is located in the second welding area and is fixed to the backlight surface of the battery cell through the second adhesive layer or the second adhesive layer and the second insulating layer.

[0022] In one embodiment, the first fine grid line is arranged to pass through the second welding area, the first fine grid line includes a first reinforcement line, the line width of the first reinforcement line is greater than the line width of the first fine grid line, and the first reinforcement line is at least partially located in the second welding area;

[0023] The second thin gate line is set to pass through the first welding area, and the second thin gate line includes a second reinforcement line. The line width of the second reinforcement line is greater than the line width of the second thin gate line, and the second reinforcement line is at least partially located in the first welding area.

[0024] In one embodiment, the first welding ribbon is located in the second welding area of the adjacent cell and fixed to the backlight surface of the adjacent cell, and the second welding ribbon is located in the first welding area of the adjacent cell and fixed to the backlight surface of the adjacent cell.

[0025] Another embodiment of the present invention provides the following technical solutions:

[0026] A photovoltaic module comprises the above-mentioned back-contact cell string.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The soldering tape in the present invention is fixed to the backlight surface of the cell by an adhesive layer or an adhesive layer and an insulating layer, which can effectively improve the welding tension between the soldering tape and the cell, and at the same time improve the current collection capacity through the design of fine grid lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a schematic structural diagram of a back-contact battery string in Example 1 of the present utility model;

[0031] Figure 2 This is a schematic cross-sectional view of the battery cell in Example 1 of the present utility model;

[0032] Figure 3 This is a schematic diagram of the planar structure of the fine grid lines on the backlight surface of the silicon wafer in Example 1 of the present utility model;

[0033] Figure 4 This is a schematic diagram of the planar structure of the doping layer on the backlight surface of the silicon wafer in Example 1 of the present utility model;

[0034] Figure 5a for Figure 1 Schematic diagram of the local structure after removing the soldering tape, adhesive layer, and insulating layer at point A in the middle;

[0035] Figure 5b for Figure 1 Schematic diagram of the local structure after removing the soldering tape, adhesive layer, and insulating layer at point B in the middle;

[0036] Figure 5c for Figure 1 Schematic diagram of the local structure after removing the solder strip and adhesive layer at point C in the middle;

[0037] Figure 6a for Figure 1 Schematic diagram of the local structure after removing the welding strip at A in the middle;

[0038] Figure 6b for Figure 1 Schematic diagram of the local structure after removing the welding strip at B;

[0039] Figure 6c for Figure 1 Schematic diagram of the local structure after removing the welding strip at C in the middle;

[0040] Figure 7a for Figure 1 Schematic diagram of the local structure at A in the middle;

[0041] Figure 7b for Figure 1 Schematic diagram of the local structure at B in the middle;

[0042] Figure 7c for Figure 1 Schematic diagram of the local structure at C in the middle;

[0043] Figure 8 for Figure 6a Schematic diagram of the local structure at D in the middle;

[0044] Figure 9 This is a schematic structural diagram of the second reinforcement line in Example 2 of the present utility model;

[0045] Figure 10 This is a schematic structural diagram of the second reinforcement line in Example 3 of the present utility model;

[0046] Figure 11 This is a schematic diagram of the partial structure of the backlight surface of the silicon wafer in Example 4 of the present utility model;

[0047] Figure 12 This is a schematic diagram of the partial structure of the backlight surface of the silicon wafer in Example 5 of the present utility model;

[0048] Figure 13 This is a schematic structural diagram of a back-contact battery string in Example 6 of the present utility model;

[0049] Figure 14 for Figure 13 Schematic diagram of the local structure at E in the middle. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only a portion of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0051] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0052] The utility model discloses a back-contact battery string, which includes multiple battery cells and multiple welding strips. Multiple frame lines and multiple fine grid lines are provided on the backlight surface of the battery cell, the frame lines are distributed along the second direction, multiple rows of fine grid lines are spaced apart along the second direction, and each row of fine grid lines is spaced apart along the first direction. The backlight surface of the battery cell includes multiple welding areas perpendicular to the fine grid lines, some fine grid lines are spaced apart on both sides of the welding area, and some fine grid lines pass through the welding area and are connected to the frame lines. Multiple adhesive layers are provided on each welding area, and multiple insulating layers are provided on the welding area adjacent to the frame line. The adhesive layer is located between two adjacent fine grid lines in the same row, and the insulating layer covers the fine grid line. The welding strip is located in the welding area and is fixed to the backlight surface of the battery cell by the adhesive layer or the adhesive layer and the insulating layer.

[0053] The utility model also discloses a photovoltaic component, comprising the above-mentioned back contact cell string.

[0054] The soldering tape in the present invention is fixed to the backlight surface of the cell by an adhesive layer or an adhesive layer and an insulating layer, which can effectively improve the welding tension between the soldering tape and the cell, and at the same time improve the current collection capacity through the design of fine grid lines.

[0055] The present invention will be further described below with reference to specific examples.

[0056] Example 1:

[0057] Ginseng Figure 1 As shown, the back contact cell string in this embodiment includes multiple cell cells 10 and welding strips 20. The cell cells are back contact (BC) cell cells. In this embodiment, a busbar-free (0BB) back contact cell cell is used as an example for explanation. The back of the cell cell only includes fine grid lines, and no busbar lines are set.

[0058] Ginseng Figure 2 Combined with Figure 3 、 Figure 4 As shown, the BC cell in this embodiment includes a silicon wafer 10, a plurality of doped layers and a plurality of fine gate lines located on the backlight side (i.e., the back side) of the silicon wafer, the doped layers include a first doped layer 101 and a second doped layer 102 of opposite doping types, the first doped layer 101 and the second doped layer 102 are arranged in a width direction (i.e., Figure 3 The first doping layer 101 is parallel to the longitudinal direction (ie, Figure 3 A plurality of first fine gate lines 121 are provided at intervals (in the lateral direction), and a plurality of second fine gate lines 122 are provided at intervals along the length direction on the second doped layer 102, and the intervals between the first fine gate lines 121 and the intervals between the second fine gate lines 122 are staggered along the length direction.

[0059] For example, the silicon wafer is an N-type silicon wafer, and the first doping layer 101 is a P-type doped polysilicon layer with a doping concentration of 1E19 cm -3 ~10E19cm -3 The second doping layer 102 is an N-type doped polysilicon layer with a doping concentration of 1E20cm -3 ~10E20cm -3 Preferably, in this embodiment, the thickness of the N-type silicon wafer is 140 μm, and the first doping layer 101 is a boron-doped polysilicon layer with a doping concentration of 8E19 cm -3 The second doping layer 102 is a phosphorus-doped polysilicon layer with a doping concentration of 3E20cm -3 .

[0060] In addition, an isolation structure 103 is provided between the first doping layer 101 and the second doping layer 102. The isolation structure 103 in this embodiment is an intrinsic polysilicon layer, but may also be an insulating layer in other embodiments. Figure 4 As shown, in this embodiment, the back side of the silicon wafer includes a first doped layer 101, an isolation structure 103, a second doped layer 102, an isolation structure 103, a first doped layer 101, an isolation structure 103, a second doped layer 102... distributed in sequence. Through the design of the isolation structure, the first doped layer 101 and the second doped layer 102 can be isolated.

[0061] Ginseng Figure 2 As shown, a front surface field (N+FSF) 105 is formed on the light-receiving surface (i.e., the front side) of the silicon wafer, and a passivation layer 106 and an anti-reflection layer 107 are sequentially stacked on the light-receiving surface of the silicon wafer. The passivation layer 106 can be a silicon dioxide (SiO2) layer, etc., and the anti-reflection layer 107 can be a silicon nitride (SiN X ) layer, etc. The front structure of the BC battery cell in this embodiment is exactly the same as that in the prior art and will not be described again here.

[0062] On the backlight side of the silicon wafer is a layer of polysilicon (Poly), which is doped in different areas to form a first doped layer (P++ area) and a second doped layer (N++ area). The P++ area and the N++ area are separated by an isolation area. Furthermore, an insulating layer 104 is stacked on top of the first doped layer, the second doped layer and the isolation structure. The first fine gate line 121 passes through the insulating layer 104 and is electrically connected to the first doped layer 101. The second fine gate line 122 passes through the insulating layer 104 and is electrically connected to the second doped layer 102. For example, the insulating layer in this embodiment is silicon nitride (SiN X ) layer, and in other embodiments may also be other insulating material layers.

[0063] Re-attend Figure 1As shown, a plurality of frame lines 11 and a plurality of fine grid lines 12 are provided on the backlight surface of the battery cell 10, the frame lines 11 are distributed along the second direction (i.e., longitudinal direction), and a plurality of rows of fine grid lines 12 are distributed at intervals along the second direction and each row of fine grid lines 12 is distributed at intervals along the first direction (i.e., transverse direction).

[0064] The backlight surface of the cell 10 includes a plurality of welding areas 13 perpendicular to the fine grid lines 12 . Some of the fine grid lines 12 are spaced apart on both sides of the welding areas 13 , and some of the fine grid lines 12 pass through the welding areas 13 and are connected to the frame lines 11 .

[0065] Among them, multiple adhesive layers 14 are provided on each welding area, and multiple insulating adhesive layers 15 are provided on the welding area adjacent to the frame line. The adhesive layer 15 is located between two adjacent fine grid lines 12 in the same row, and the insulating adhesive layer 15 covers the fine grid line 12. The welding strip 20 is located in the welding area 13 and is fixed to the backlight surface of the battery cell 10 through the adhesive layer 14 or the adhesive layer 14 and the insulating adhesive layer 15.

[0066] Ginseng Figure 1 Combined with Figures 5a to 5c As shown, the border line 11 in this embodiment includes a first border line 111 and a second border line 112 arranged relatively to each other along a first direction (i.e., horizontal direction), and the fine gate line 12 includes a plurality of rows of first fine gate lines 121 and second fine gate lines 122 alternately distributed along a second direction (i.e., vertical direction), the first border line 111 is connected to the first fine gate line 121, and the second border line 112 is connected to the second fine gate line 122.

[0067] The welding area 13 in this embodiment includes a first welding area 131 and a second welding area 132 that are alternately distributed along a first direction (i.e., transverse direction). Some of the first fine grid lines 121-1 are spaced apart on both sides of the first welding area 131, and some of the first fine grid lines 121-2 are arranged through the first welding area 131 and connected to the first frame line 111; some of the second fine grid lines 122-1 are spaced apart on both sides of the second welding area 132, and some of the second fine grid lines 122-2 are arranged through the second welding area 132 and connected to the second frame line 112.

[0068] For example, in this embodiment, taking a half-cell BC battery with a length of 182 mm as an example, there are 20 alternating first welding areas 131 and second welding areas 132 along the first direction, and the leftmost first welding area 131 is adjacent to the first frame line 111, and the rightmost second welding area 132 is adjacent to the second frame line 112. The width of the first welding area 132 and the second welding area 132 are both 0.9 mm.

[0069] In this embodiment, the line width of the first fine gate line 121-2 is greater than the line width of the first fine gate line 121-1, and the line width of the second fine gate line 122-2 is greater than the line width of the second fine gate line 122-1. Exemplarily, the line widths of the first fine gate line 121-1 and the second fine gate line 122-1 are both 6 μm, and the line widths of the first fine gate line 121-2 and the second fine gate line 122-2 are both 32 μm.

[0070] The first fine gate lines 121-2 are connected to the first frame line 111. Multiple shorter first fine gate lines 121-1 are connected to the first frame line 111. Current can be collected at the edge portion via the first fine gate lines 121-2. Thickening the first fine gate lines 121-2 can improve the current collection capability at the edge portion. Similarly, the second fine gate lines 122-2 can also collect current at the right edge portion, which will not be further described here.

[0071] In addition, the first fine gate line 121-1 in this embodiment also includes a first reinforcement line 123, the line width of the first reinforcement line 123 is greater than the line width of the first fine gate line 121-1, and the first reinforcement line 123 is at least partially located in the second welding area 132, the second fine gate line 122-1 is set through the first welding area 131, the second fine gate line 122-1 includes a second reinforcement line 124, the line width of the second reinforcement line 124 is greater than the line width of the second fine gate line 122-1, and the second reinforcement line 123 is at least partially located in the first welding area 131.

[0072] For example, in this embodiment, the first reinforcement line 123 is located in the middle of the second welding area 132, and the second reinforcement line 124 is located in the middle of the first welding area 131. The line width of the first reinforcement line 123 and the second reinforcement line 124 are both 80μm, the length is 0.8mm, and the height is 6μm.

[0073] The first reinforcing wire 123 and the second reinforcing wire 124 are used to contact the welding strip when welding the welding strip. The reinforcing wire has a larger line width to improve the current collection capacity of the welding strip.

[0074] Furthermore, in this embodiment, in the welding area adjacent to the frame line, the welding ribbon is fixed to the backlight surface of the battery cell through the adhesive layer and the insulating adhesive layer, and in the remaining welding areas, the welding ribbon is fixed to the backlight surface of the battery cell through the adhesive layer.

[0075] Ginseng Figures 6a to 6c Combined with Figures 7a to 7c As shown, the welding strips in this embodiment include first welding strips 21 and second welding strips 22 alternately distributed along a first direction. The first welding strips 21 are located in the first welding area 131 , and the second welding strips 22 are located in the second welding area 132 .

[0076] Multiple first adhesive layers 141 are provided on each first welding area 131. Multiple first insulating layers 151 are provided on the first welding area 131 adjacent to the first frame line 111. The first adhesive layer 141 is located between two adjacent first fine grid lines 121 in the same row, and the first insulating layer 151 covers the first fine grid line 121-2. In the first welding area 131 adjacent to the first frame line 111, the first welding ribbon 21 is secured to the backlight surface of the cell via the first adhesive layer 141 and the first insulating layer 151. In the other first welding areas 131, the first welding ribbon 21 is secured to the backlight surface of the cell only via the first adhesive layer 141.

[0077] Multiple second adhesive layers 142 are provided on each second welding area 132. Multiple second insulating layers 152 are provided on the second welding area 132 adjacent to the second border line 112. The second adhesive layer 142 is located between two adjacent second fine grid lines 122 in the same row, and the second insulating layer 152 covers the second fine grid line 122-2. In the second welding area 132 adjacent to the second border line 112, the second welding ribbon 22 is secured to the backlight surface of the cell via the second adhesive layer 142 and the first insulating layer 152. In the other second welding areas 132, the second welding ribbon 22 is secured to the backlight surface of the cell only via the second adhesive layer 142.

[0078] The insulating adhesive layer in the present invention is printed and cured with insulating adhesive, and the adhesive layer is printed and cured with non-conductive adhesive. The insulating adhesive layer and the adhesive layer can be printed simultaneously or in steps, and can be cured simultaneously or in steps. The specific process will not be repeated here.

[0079] In this embodiment, multiple adhesive layers are spaced apart within each welding area, and multiple insulating layers are spaced apart within the welding area adjacent to the frame line. For example, an adhesive layer is provided for every 16 first or second fine grid lines, and an insulating layer is provided for every 14 first or second fine grid lines. The provision of adhesive and insulating layers improves the curing effect of the solder ribbon and the cell, ensuring subsequent welding performance and ultimately increasing the welding tension between the solder ribbon and the cell.

[0080] Example 2:

[0081] In this embodiment, in the welding area adjacent to the frame line, the height of the reinforcement line close to the insulating adhesive layer is greater than the height of the reinforcement line away from the insulating adhesive layer.

[0082] Ginseng Figure 6a Combined with Figure 8 、 Figure 9As shown, in the first welding area 31 adjacent to the first frame line 111, 13 second reinforcement lines 124 are spaced apart between the two first insulating adhesive layers 151, wherein the heights of the first fine gate lines 121-2 and the second fine gate lines 122 are both 6 μm, and the heights of the two second reinforcement lines 124 adjacent to each first insulating adhesive layer 151 are designed to be higher, and the heights of the other second reinforcement lines are equal to the height of the fine gate lines, which is 6 μm.

[0083] Specifically, in this embodiment, the height of the second reinforcing line 124-1 adjacent to the first insulating rubber layer 151 is 26μm, the height of the second reinforcing line 124-2 next to the second reinforcing line 124-1 is 16μm, and the height of the remaining second reinforcing lines 124-3 is 6μm, and the upper surface of each second reinforcing line is flat.

[0084] Because the first insulating adhesive layer 151 is printed on the first fine grid lines 121-2, the soldering height of the first soldering ribbon increases. Raising the second reinforcing lines 124 adjacent to the first insulating adhesive layer 151 can prevent sudden changes in soldering height, thereby increasing the soldering strength of the soldering ribbon. Similarly, the first reinforcing lines 123 adjacent to the second fine grid lines 122-2 are also raised, but this will not be further described here.

[0085] It should be understood that the number of reinforced lines to be raised and the height of the raised lines are not limited to the above embodiments, and any technical solution for raising the reinforced lines beside the fine grid lines falls within the scope of protection of the present utility model.

[0086] Example 3:

[0087] In this embodiment, in the welding area adjacent to the frame line, the upper surface of the reinforcing line adjacent to the insulating adhesive layer is inclined or curved toward the backlight surface of the battery cell in a direction away from the insulating adhesive layer.

[0088] Ginseng Figure 10 As shown, in the first welding area 31 adjacent to the first frame line 111, the height of the first fine grid line 121-2 and the second fine grid line 122 are both 6μm, and the height of the two second reinforcement lines 124 adjacent to each first insulating glue layer 151 is designed to be increased, and the upper surface is a slope, and the height of the other second reinforcement lines is equal to the height of the fine grid lines, which is 6μm, and the upper surface is a plane.

[0089] Specifically, in this embodiment, the height of the second reinforcing line 124-1 adjacent to the first insulating rubber layer 151 gradually decreases from 26 μm to 21 μm in the direction away from the first insulating rubber layer 151, and the height of the second reinforcing line 124-2 next to the second reinforcing line 124-1 gradually decreases from 16 μm to 11 μm in the direction away from the first insulating rubber layer 151. The height of the remaining second reinforcing line 124-3 is 6 μm.

[0090] Similarly, the first reinforcing line 123 beside the second fine gate line 122 - 2 is also designed to be elevated, and its upper surface is an inclined surface, which will not be further described here.

[0091] In this embodiment, the welding tension of the welding strip can be further increased by raising the reinforcing wires beside the insulating adhesive layer and setting the surface to be an inclined surface.

[0092] It should be understood that the number of reinforcement lines to be raised, the height of the raising, the angle of inclination, etc. are not limited to the above embodiments. In other embodiments, the upper surface can also be set as a curved surface, etc., which will not be illustrated one by one here.

[0093] Example 4:

[0094] In the welding area adjacent to the frame line, a first connecting line is provided between at least two reinforcing lines adjacent to the insulating adhesive layer.

[0095] Ginseng Figure 11 As shown, in this embodiment, within the first welding region 31 adjacent to the first frame line 111, a first connecting wire 161 is provided between two second reinforcing wires 124 adjacent to the first insulating layer 151, and both ends of the second reinforcing wire 124 are connected to the second fine grid lines 122. Similarly, within the second welding region 32 adjacent to the second frame line 112, the same structural design is also adopted.

[0096] Specifically, the line width and height of the first connecting line 161 are consistent with the line width and height of the first fine gate line 121 - 1 and the second fine gate line 122 - 1 , and the length thereof is the distance between two adjacent second reinforcing lines 124 .

[0097] In this embodiment, the design of the first connecting wire allows two thin gate lines adjacent to the insulating layer to be electrically connected, thereby avoiding the problem of the insulating layer covering the adjacent thin gate lines and preventing current from being collected. Of course, in other embodiments, three or more reinforcing wires adjacent to the insulating layer can also be connected via the first connecting wire.

[0098] Example 5:

[0099] In the welding area adjacent to the frame line, the reinforcing line close to the insulating layer is disconnected from the thin grid lines in its row, and a second connecting line is provided between the thin grid lines in the row where the reinforcing line is located and the thin grid lines away from the insulating layer.

[0100] Ginseng Figure 12As shown, in this embodiment, in the first welding area 31 adjacent to the first frame line 111, the second reinforcement line 124 adjacent to the first insulating rubber layer 151 is disconnected from the second fine grid line 122 in its row, and a second connecting line 162 is provided between the second fine grid line 122 in the row where the second reinforcement line 124 is located and the second fine grid line 122 away from the first insulating rubber layer 151. In other words, the first second fine grid line 122 next to the first insulating rubber layer 151 is disconnected from the second reinforcement line 124 and connected to the second second fine grid line 122 via two second connecting lines 162, and the second second fine grid line 122 is connected to the second reinforcement line 124. Similarly, the same structural design is adopted in the second welding area 32 adjacent to the second frame line 112.

[0101] Specifically, the line width and height of the second connection line 162 are consistent with the line width and height of the first fine gate line 121 - 1 and the second fine gate line 122 - 1 , and the length is the distance between two adjacent second fine gate lines 122 - 1 .

[0102] In this embodiment, the second connecting wire design allows the fine gate lines adjacent to the insulating layer to be conductive, thereby avoiding the problem of the insulating layer covering the adjacent fine gate lines and preventing current from being collected. Of course, in other embodiments, three or more fine gate lines adjacent to the insulating layer can also be connected via the second connecting wire.

[0103] Example 6:

[0104] Ginseng Figure 13 、 Figure 14 As shown, in this embodiment, two back-contact battery cells are connected in series as an example, including adjacent battery cells 10 - 1 and 10 - 2 , and the battery cells 10 - 1 and 10 - 2 are connected in series through multiple first welding ribbons 21 and multiple second welding ribbons 22 .

[0105] Specifically, the cells 10-1 and 10-2 are welded together using a first welding ribbon 21. The first border line 111 of the cell 10-1 is on the left side, and the second border line 112 is on the right side. The first border line 111 of the cell 10-2 is on the right side, and the second border line is on the left side. The first welding ribbon 21 is welded to the first welding area 31 of the cell 10-1 and the second welding area 32 of the cell 10-2. The first welding ribbon 21 is electrically connected to the second fine grid lines 122 in the cell 10-1 and the first fine grid lines 121 in the cell 10-2.

[0106] A second welding ribbon 22 is welded to the second welding region 32 of the cell 10-1 and to the first welding region of the cell on the other side of the cell 10-1 (not shown). This welding ribbon is electrically connected to the first fine grid lines 121 in the cell 10-1. A second welding ribbon 22 is welded to the first welding region 31 of the cell 10-2 and to the second welding region of the cell on the other side of the cell 10-2 (not shown). This welding ribbon is electrically connected to the second fine grid lines 122 in the cell 10-2.

[0107] In this way, multiple battery cells can be connected in series, thereby achieving a series connection of multiple battery cells.

[0108] In other embodiments, if the battery cells need to be connected in parallel, different welding ribbons may be used to weld the battery cells in the same welding area of two adjacent battery cells, which will not be described in detail here.

[0109] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0110] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A back contact battery string, characterized in that: The back-contact battery string includes multiple battery cells and multiple welding strips, and the backlight surface of the battery cell is provided with multiple frame lines and multiple fine grid lines, the frame lines are distributed along the second direction, multiple rows of fine grid lines are spaced apart along the second direction, and each row of fine grid lines is spaced apart along the first direction. The backlight surface of the battery cell includes multiple welding areas perpendicular to the fine grid lines, some of the fine grid lines are spaced apart on both sides of the welding area, and some of the fine grid lines are arranged through the welding area and are connected to the frame lines. Each of the welding areas is provided with multiple adhesive layers, and the welding area adjacent to the frame line is provided with multiple insulating layers. The adhesive layer is located between two adjacent fine grid lines in the same row, and the insulating layer covers the fine grid line. The welding strip is located in the welding area and is fixed to the backlight surface of the battery cell through the adhesive layer or the adhesive layer and the insulating layer.

2. The back contact cell string according to claim 1, characterized in that In the welding area adjacent to the frame line, the welding ribbon is fixed to the backlight surface of the battery cell through the adhesive layer and the insulating layer. In the remaining welding areas, the welding ribbon is fixed to the backlight surface of the battery cell through the adhesive layer.

3. The back contact cell string according to claim 1, characterized in that: The fine gate lines further include reinforcement lines. The reinforcement lines are at least partially located in the welding region, and the line width of the reinforcement lines is greater than the line width of the fine gate lines.

4. The back contact cell string according to claim 3, characterized in that: In the welding area adjacent to the frame line, the height of the reinforcement line close to the insulating adhesive layer is greater than the height of the reinforcement line away from the insulating adhesive layer.

5. The back contact cell string according to claim 3, characterized in that: In the welding area adjacent to the frame line, the upper surface of the reinforcement line close to the insulating adhesive layer is flat, or is inclined or curved in a direction away from the insulating adhesive layer toward the backlight surface of the battery cell.

6. The back contact cell string according to claim 1, characterized in that: In the welding area adjacent to the frame line, a first connecting line is provided between at least two reinforcing lines adjacent to the insulating adhesive layer.

7. The back contact cell string according to claim 1, characterized in that: In the welding area adjacent to the frame line, the reinforcing line close to the insulating layer is disconnected from the thin grid lines in its row, and a second connecting line is provided between the thin grid lines in the row where the reinforcing line is located and the thin grid lines away from the insulating layer.

8. The back contact cell string according to claim 1, characterized in that: The frame lines include a first frame line and a second frame line arranged opposite to each other along a first direction, and the fine gate lines include multiple rows of first fine gate lines and second fine gate lines alternately distributed along a second direction. The first frame lines are connected to the first fine gate lines, and the second frame lines are connected to the second fine gate lines.

9. The back contact cell string according to claim 8, characterized in that: The welding area includes a first welding area and a second welding area alternately distributed along a first direction; Some of the first thin grid lines are spaced apart and distributed on both sides of the first welding area, and some of the first thin grid lines pass through the first welding area and are connected to the first border line; Some of the second thin gate lines are spaced apart and distributed on both sides of the second welding area, and some of the second thin gate lines pass through the second welding area and are connected to the second border line.

10. The back contact cell string according to claim 9, characterized in that: The welding strips include first welding strips and second welding strips alternately distributed along a first direction; A plurality of first adhesive layers are provided on each first welding area, a plurality of first insulating layers are provided on the first welding area adjacent to the first border line, the first adhesive layer is located between two adjacent first fine grid lines in the same row, the first insulating layer covers the first fine grid lines, the first welding ribbon is located in the first welding area and is fixed to the backlight surface of the solar cell by the first adhesive layer or the first adhesive layer and the first insulating layer; Multiple second adhesive layers are provided on each second welding area, and multiple second insulating layers are provided on the second welding area adjacent to the second border line. The second adhesive layer is located between two adjacent second fine grid lines in the same row, and the second insulating layer covers the second fine grid lines. The second welding strip is located in the second welding area and is fixed to the backlight surface of the battery cell through the second adhesive layer or the second adhesive layer and the second insulating layer.

11. The back contact cell string according to claim 9, characterized in that: The first fine grid line is arranged to pass through the second welding area, the first fine grid line includes a first reinforcement line, the line width of the first reinforcement line is greater than the line width of the first fine grid line, and the first reinforcement line is at least partially located in the second welding area; The second thin gate line is set to pass through the first welding area, and the second thin gate line includes a second reinforcement line. The line width of the second reinforcement line is greater than the line width of the second thin gate line, and the second reinforcement line is at least partially located in the first welding area.

12. The back contact cell string according to claim 10, characterized in that: The first welding strip is located in the second welding area of the adjacent battery cell and is fixed to the backlight surface of the adjacent battery cell. The second welding strip is located in the first welding area of the adjacent battery cell and is fixed to the backlight surface of the adjacent battery cell.

13. A photovoltaic module, characterized in that: The photovoltaic module comprises the back-contact cell string according to any one of claims 1 to 12.

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