Solar cell and method of manufacturing the same, photovoltaic module

Abstract

Embodiments of the present application provide a solar cell and a preparation method thereof, and a photovoltaic module, and relate to the technical field of photovoltaic, aiming to reduce the risk of cracking of the solar cell. In the solar cell, a plurality of first solder strips and a plurality of second solder strips are arranged on the back surface of the cell piece. An insulating strip is arranged on the side of the second solder strip away from the cell piece. A first conductive foil is arranged on the side of the insulating strip away from the cell piece and is electrically connected with the plurality of first solder strips. An encapsulation cover plate is arranged on the side of the first conductive foil away from the cell piece and is provided with an opening. A conductive bending structure is bent to form a first part and a second part, the first part is electrically connected with the first conductive foil, and the second part is led out to the outside of the encapsulation cover plate through the opening. The thickness of the first conductive foil is less than or equal to the thickness of the conductive bending structure, the first part partially overlaps with the first conductive foil, and the opening exposes the overlapping part of the first part and the first conductive foil. The solar cell can be applied to the photovoltaic module to convert light energy into electrical energy.

Description

TECHNICAL FIELD

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

[0002] The bus bar area structure of the solar cell has many layers, so that the total thickness of the area is thick, and the solar cell is prone to cracking during lamination.

[0003] At present, how to reduce the cracking risk of the solar cell is a problem to be solved in the field. SUMMARY

[0004] The present application provides a solar cell, a preparation method thereof and a photovoltaic module, which aims to reduce the cracking risk of the solar cell.

[0005] In a first aspect, the present application provides a solar cell, which comprises a cell piece, a plurality of first solder strips and a plurality of second solder strips, a plurality of insulating strips, a first conductive foil, an encapsulation cover plate and a conductive bending structure. The cell piece comprises opposite front and back surfaces. The plurality of first solder strips and the plurality of second solder strips are arranged on the back surface, and the first solder strips and the second solder strips are arranged alternately along a first direction parallel to the back surface. One insulating strip is arranged on a side of one second solder strip away from the cell piece. The first conductive foil is arranged on a side of the insulating strip away from the cell piece, and the first conductive foil is electrically connected with the plurality of first solder strips. The encapsulation cover plate is arranged on a side of the first conductive foil away from the cell piece, and the encapsulation cover plate is provided with an opening. The conductive bending structure is bent to form a first part and a second part, the first part is electrically connected with the first conductive foil, and the second part is led out to the outside of the encapsulation cover plate through the opening. The thickness of the first conductive foil is less than or equal to the thickness of the conductive bending structure, the first part partially overlaps with the first conductive foil, and the opening exposes the part of the first part overlapping with the first conductive foil.

[0006] The solar cell provided by the present application comprises a cell piece, a plurality of first solder strips and a plurality of second solder strips, a plurality of insulating strips, a first conductive foil, an encapsulation cover plate and a conductive bending structure. The plurality of first solder strips and the plurality of second solder strips, the plurality of insulating strips, the conductive foil and the encapsulation cover plate are arranged on the back surface of the cell piece in sequence. The encapsulation cover plate is provided with an opening, the conductive bending structure comprises a first part and a second part, the first part is electrically connected with the first conductive foil, and the second part is led out to the outside of the encapsulation cover plate through the opening. Since the thickness of the first conductive foil is less than or equal to the thickness of the conductive bending structure, the overall thickness of the solar cell is reduced, thereby reducing the risk of hidden cracking or cracking of the solar cell.

[0007] Due to the large thickness of the area where the first part overlaps the first conductive foil, by exposing the part where the first part overlaps the first conductive foil through the opening, the encapsulation cover plate can avoid the thick overlapping area, so that the thickness of the film layer under the encapsulation cover plate is uniform, and the problem of hidden cracks or cracks of the solar cell due to stress concentration during lamination of the solar cell can be avoided.

[0008] In some embodiments, the conductive bending structure is a bus bar, and the thickness of the first conductive foil is less than the thickness of the bus bar.

[0009] In some embodiments, the ratio of the thickness of the bus bar to the thickness of the first conductive foil ranges from 1.67 to 20.

[0010] In some embodiments, the material of the first conductive foil is different from the material of the bus bar.

[0011] In some embodiments, the first part is welded with the first conductive foil. Alternatively, the first part is electrically connected with the first conductive foil through conductive glue.

[0012] In some embodiments, the first part includes a second conductive foil, and the second part includes a third conductive foil and a bus bar. The thicknesses of the first conductive foil, the second conductive foil and the third conductive foil are equal, and are less than the thickness of the bus bar.

[0013] In some embodiments, the materials of the first conductive foil, the second conductive foil and the third conductive foil are the same and are integrally arranged. The materials of the first conductive foil, the second conductive foil and the third conductive foil are different from the material of the bus bar.

[0014] In some embodiments, in the second part, the third conductive foil is welded with the bus bar. Alternatively, the third conductive foil is electrically connected with the bus bar through conductive glue.

[0015] In some embodiments, along a second direction parallel to the back surface, the width of the first conductive foil is greater than the width of the conductive bending structure, and the second direction intersects the first direction.

[0016] In some embodiments, the width of the first conductive foil ranges from 16.7mm to 210mm.

[0017] In some embodiments, the ratio of the size of the opening to the width of the conductive bending structure is greater than or equal to 1.2.

[0018] In some embodiments, along a second direction parallel to the back surface, the cross-sectional area of the first conductive foil is greater than or equal to the cross-sectional area of the conductive bending structure, and the second direction intersects the first direction.

[0019] In some embodiments, the first conductive foil is electrically connected with the first solder strip through a metal interconnection layer or conductive glue.

[0020] In a second aspect, the present application also provides a method for manufacturing a solar cell, the method comprising: providing a cell sheet, the cell sheet comprising opposite front and back surfaces; disposing a plurality of first solder ribbons and a plurality of second solder ribbons on the back surface, the first solder ribbons and the second solder ribbons being arranged alternately along a first direction parallel to the back surface; disposing a plurality of insulating strips on the back surface, one insulating strip being disposed on a side of one second solder ribbon away from the cell sheet; disposing a first conductive foil and a conductive bending structure on the back surface, the first conductive foil and the conductive bending structure being disposed on a side of the insulating strip away from the cell sheet, and the first conductive foil being electrically connected to the plurality of first solder ribbons; and disposing an encapsulation cover plate on a side of the first conductive foil away from the cell sheet, the encapsulation cover plate being provided with an opening.

[0021] The method provided by the present application comprises: disposing a plurality of first solder ribbons and a plurality of second solder ribbons on the back surface of the cell sheet, disposing a plurality of insulating strips on the back surface, one insulating strip being disposed on a side of one second solder ribbon away from the cell sheet, so as to insulate the second solder ribbon from a metal conductive layer above the second solder ribbon; disposing a first conductive foil and a conductive bending structure on the back surface, the first conductive foil and the conductive bending structure being disposed on a side of the insulating strip away from the cell sheet, and the first conductive foil being electrically connected to the plurality of first solder ribbons, i.e., the first conductive foil functions as a current collector; and disposing an encapsulation cover plate on a side of the first conductive foil away from the cell sheet, the encapsulation cover plate being provided with an opening.

[0022] The conductive bending structure is bent to form a first part and a second part, the first part is electrically connected to the first conductive foil, and the second part is led out to the outside of the encapsulation cover plate through the opening. The thickness of the first conductive foil is less than or equal to the thickness of the conductive bending structure. By disposing the first conductive foil with a smaller thickness, the overall thickness of the solar cell is reduced, the risk of stress concentration and the risk of solder joint failure are reduced, and thus the risk of hidden cracks or broken pieces of the solar cell is reduced.

[0023] The thickness of the region where the first part overlaps the first conductive foil is large. By exposing the part where the first part overlaps the first conductive foil through the opening, the encapsulation cover plate can avoid the thick overlapping region, so that the thickness of the film layer under the encapsulation cover plate is uniform, and the problem of hidden cracks or broken pieces of the solar cell due to stress concentration during lamination of the solar cell can be avoided.

[0024] In some embodiments, the method of providing a first conductive foil and a conductive bending structure on the back side includes: using an adhesive bonding process to connect the first conductive foil to a plurality of first solder strips. After providing the encapsulation cover, the above preparation method further includes using a lamination process to electrically connect the first conductive foil to the plurality of first solder strips.

[0025] In some embodiments, the conductive bending structure is a busbar. Before the first conductive foil and the conductive bending structure are disposed on the back side, the above preparation method further includes: connecting the busbar to the first conductive foil. The bent busbar forms a first part and a second part, and the first part is electrically connected to the first conductive foil.

[0026] In some embodiments, the first part includes a second conductive foil, and the second part includes a third conductive foil and a busbar. Before forming the first conductive foil and the conductive bending structure on the back side, the above-described preparation method further includes: forming a conductive foil, the conductive foil including an integrally formed first conductive foil, second conductive foil, and third conductive foil; connecting the busbar to the third conductive foil to form a conductive structure; and bending the conductive structure along the boundary line between the second and third conductive foils.

[0027] Thirdly, this application also provides a photovoltaic module comprising a plurality of solar cells as described in any of the above embodiments, wherein the plurality of solar cells are electrically connected.

[0028] The aforementioned photovoltaic modules have the same beneficial technical effects as solar cells, and will not be elaborated further here. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in some embodiments of this application will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not actual dimensions of the products or actual processes of the methods involved in the embodiments of this application.

[0030] Figure 1 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application;

[0031] Figure 2 for Figure 1 A magnified view of the photovoltaic module at point M;

[0032] Figure 3 for Figure 2 A cross-sectional view of the photovoltaic module along section line AA';

[0033] Figure 4 for Figure 2 A schematic diagram showing the positional relationship of the insulating strip, main grid, and sub-grid in a [structure / system].

[0034] Figure 5 for Figure 2 Another schematic diagram showing the positional relationship between the insulating strip, the main grid, and the sub-grid;

[0035] Figure 6 A schematic diagram of the structure of the first conductive foil provided in an embodiment of this application;

[0036] Figure 7 A schematic diagram of a conductive bending structure provided for an embodiment of this application;

[0037] Figure 8 for Figure 2 A schematic diagram showing the connection between the conductive bending structure and the first conductive foil;

[0038] Figure 9 A flowchart illustrating a method for fabricating a solar cell, provided as an embodiment of this application;

[0039] Figures 10-13 for Figure 9 A step diagram of the preparation method in the image;

[0040] Figure 14 A step diagram illustrating the formation of the first conductive foil and the conductive bending structure provided for embodiments of this application;

[0041] Figure 15 This is a schematic diagram of the structure of the solar cell provided in this application;

[0042] Figure 16 for Figure 15 A schematic diagram showing the connection between the conductive bending structure and the first conductive foil;

[0043] Figure 17 for Figure 9 Another step diagram of the preparation method in the image;

[0044] Figure 18 and Figure 19 The diagram shows the steps involved in forming the first conductive foil and the conductive bending structure, as provided in the embodiments of this application. Detailed Implementation

[0045] The technical solutions in some embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application are within the scope of protection of this application.

[0046] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and encompassing, that is, "including, but not limited to".

[0047] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0048] In describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. For example, in describing some embodiments, the term "connection" may be used to indicate that two or more components have direct physical or electrical contact with each other.

[0049] In addition, the use of “based on” implies openness and inclusivity, because processes, steps, calculations or other actions “based on” one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0050] This document describes exemplary embodiments with reference to cross-sectional views as idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0051] An embodiment of this application provides a photovoltaic module. Figure 1 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application. The photovoltaic module 100 includes multiple solar cells 10, which are electrically connected. The number of solar cells 10 within the photovoltaic module can be adjusted as needed to convert solar energy into electrical energy.

[0052] Figure 2 for Figure 1 A magnified view of the photovoltaic module at point M; Figure 3 for Figure 2 A cross-sectional view of the photovoltaic module along section line AA'.

[0053] Referring to Figure 2 Embodiments of the present application also provide a solar cell 10, which comprises a cell sheet 1, a plurality of first solder strips 21 and a plurality of second solder strips 22, a plurality of insulating strips 3, a first conductive foil 4, an encapsulating cover plate 5 and a conductive bending structure 6.

[0054] The cell sheet 1 comprises opposite front and back surfaces, Figure 2 The back surface of the cell sheet 1 is shown in FIG. 1. The plurality of first solder strips 21 and the plurality of second solder strips 22 are arranged on the back surface, and the first solder strips 21 and the second solder strips 22 are arranged alternately along a first direction (direction X) parallel to the back surface.

[0055] Referring to Figure 3 The solar cell 10 further comprises a plurality of first main grids 71 and a plurality of second main grids 72, which are arranged alternately along the first direction X. Exemplarily, the material of the plurality of first main grids 71 and the material of the plurality of second main grids 72 can be silver paste. The polarity of the first main grids 71 and the second main grids 72 is different, and exemplarily, the first main grids 71 are positive main grids and the second main grids 72 are negative main grids, or the first main grids 71 are negative main grids and the second main grids 72 are positive main grids. Embodiments of the present application are described by taking the first main grids 71 as positive main grids and the second main grids 72 as negative main grids as an example.

[0056] The first solder strips 21 are located above the first main grids 71 and cover the first main grids 71, and the second solder strips 22 are located above the second main grids 72 and cover the second main grids 72, i.e. the first solder strips 21 are positively charged and the second solder strips 22 are negatively charged. Exemplarily, tin paste points 90 are arranged between the first solder strips 21 and the first main grids 71 and between the second solder strips 22 and the second main grids 72, and the electrical connection between the main grids and the solder strips is realized through the tin paste points 90.

[0057] Continuing to refer to Figure 2 and Figure 3 The plurality of insulating strips 3 are arranged along the first direction X, and one insulating strip 3 is arranged on the side of one second solder strip 22 away from the cell sheet 1. The insulating strip 3 is used to insulate the second solder strip 22 from the first conductive foil 4. The first conductive foil 4 is arranged on the side of the insulating strip 3 away from the cell sheet 1, and the first conductive foil 4 is electrically connected to the plurality of first solder strips 21, i.e. the first conductive foil 4 is electrically connected to the positively charged solder strips, and the positive electricity is collected in the first conductive foil 4.

[0058] Exemplarily, continuing to refer to Figure 2 and Figure 3The first conductive foil 4 is electrically connected to multiple first solder ribbons 21 via a metal interconnect layer (or conductive adhesive) 9. For example, the metal interconnect layer 9 can be made of solder paste, and the conductive adhesive 9 can be made of pressure-sensitive tape. The first conductive foil 4 is electrically connected to the multiple first solder ribbons 21 via the metal interconnect layer (or conductive adhesive) 9, meaning that the first conductive foil 4 and the first solder ribbons 21 do not need to be directly soldered, thereby reducing the impact of the high temperature during soldering of the first conductive foil 4 and the first solder ribbons 21 on the main grid located below the solder ribbons. Furthermore, the absence of solder joints between the first conductive foil 4 and the first solder ribbons 21 reduces the damage to the battery cell 1 caused by direct soldering. When the first conductive foil 4 is subjected to external pulling force, the stress is concentrated at this point. Since there are no solder joints between the first conductive foil 4 and the first solder ribbons 21, the possibility of alloy layer breakage and desoldering between the solder paste point 90 and the main grid is reduced, thereby improving the strength and reliability of the solder paste point.

[0059] See Figure 3 The solar cell 10 also includes multiple first sub-grids 81 and multiple second sub-grids 82, arranged alternately along a second direction parallel to the back surface. The first direction intersects the second direction; for example, the first direction is perpendicular to the second direction, where the first direction is direction X and the second direction is direction Y. That is, the multiple first sub-grids 81 and multiple second sub-grids 82 are arranged perpendicularly to the multiple first main grids 71 ​​and multiple second main grids 72.

[0060] The first sub-gate 81 and the second sub-gate 82 have different polarities. For example, the first sub-gate 81 is a positive sub-gate and the second sub-gate 82 is a negative sub-gate, or the first sub-gate 81 is a negative sub-gate and the second sub-gate 82 is a positive sub-gate. The embodiments of this application are illustrated with the example of the first sub-gate 81 being a positive sub-gate and the second sub-gate 82 being a negative sub-gate.

[0061] See also Figure 3 Electrical connection is achieved through contact between the main gate and the secondary gate of the same polarity. An insulating layer 31 is provided between the main gate and the secondary gate of different polarities. For example, the insulating layer 31 can be any one of insulating adhesive or insulating block. In the embodiments of this application, the first main gate 71 is in direct contact with the first secondary gate 81, an insulating layer 31 is provided between the first main gate 71 and the second secondary gate 82, the second main gate 72 is in direct contact with the second secondary gate 82, and an insulating layer 31 is provided between the second main gate 72 and the first secondary gate 81.

[0062] Figure 4 for Figure 2 A schematic diagram showing the positional relationship of the insulating strip, main grid, and sub-grid in a [structure / system]. Figure 5 for Figure 2 Another schematic diagram showing the positional relationship between the insulating strip, the main grid, and the sub-grid.

[0063] like Figure 4 andFigure 5 As shown, the insulation strip 3 in the embodiments of the present application can have two settings, both of which can achieve insulation of the grid lines of different polarities in the solar cell 10.

[0064] For example, referring to Figure 4 , the solar cell 10 further comprises an insulating glue 30, which is printed between the first main grid 71 and the second main grid 72 to cover the sub-grid of the same polarity as the second solder strip 22, i.e., the second sub-grid 82, so as to achieve insulation of the second sub-grid 82 with negative electricity and the second solder strip 22 from the first conductive foil 4 with positive electricity. In this case, the width W1 of the insulation strip 3 only needs to cover the width d1 of the second solder strip 22, for example, W1>d1+2mm. The distance between the first main grid 71 and the second main grid 72 is x, and the distance d2 between the adjacent two insulation strips 3 is d2=2x-W1.

[0065] For example, referring to Figure 5 , only the insulation strip 3 is provided between the second solder strip 22 and the first conductive foil 4, and the insulation strip 3 needs to cover the second solder strip 22 and the sub-grid of the same polarity as the second solder strip 22, i.e., the second sub-grid 82, so as to achieve insulation of the second sub-grid 82 with negative electricity and the second solder strip 22 from the conductive foil 4 with positive electricity. In this case, the width W1 of the insulation strip 3 is W1>2x-1mm, and the distance d2 between the adjacent two insulation strips 3 is d2=d1+1mm.

[0066] Figure 6 A structural schematic diagram of the first conductive foil provided in the embodiments of the present application.

[0067] For example, referring to Figure 2 and Figure 6 , Figure 6 (1) shows a top view of the first conductive foil 4, i.e., the orthographic projection of the first conductive foil 4 on the cell sheet 1, Figure 6 (2) shows a front view of the first conductive foil 4. For example, referring to Figure 6 (1), the length L1 of the first conductive foil 4 is set to cover at least the width of the plurality of first solder strips 21 along the first direction (direction X), so as to ensure that the first conductive foil 4 collects all the charges carried on the first solder strips 21. For example, referring to Figure 6 (2), the thickness of the first conductive foil 4 is d1, and the width of the first conductive foil 4 is W2.

[0068] Continuing to refer to Figure 2 , the packaging cover plate 5 is arranged on the side of the first conductive foil 4 away from the cell sheet 1, and the packaging cover plate 5 is provided with an opening 51. For example, the material of the packaging cover plate 5 can be glass.

[0069] Figure 7 A structural schematic diagram of a conductive bending structure provided in the embodiments of the present application.

[0070] Referring to Figure 2 and Figure 7 , the conductive bending structure 6 is bent to form a first portion 61 and a second portion 62, the first portion 61 is electrically connected with the first conductive foil 4, and the second portion 62 is led out of the packaging cover plate 5 through the opening 51 and is electrically connected with the junction box.

[0071] For example, referring to Figure 7 (1), the length L3 of the first portion 61 is greater than or equal to 5 mm, which is used to control the contact area of the first portion 61 with the first conductive foil 4 to ensure the electrical connection between the first portion 61 and the first conductive foil 4. The width of the conductive bending structure 6 is W3. The length L4 of the second portion 62 is in the range of 20 mm to 24 mm, and the length L4 in this range is convenient for electrical connection with the junction box.

[0072] Referring to Figure 8 (2), the thickness of the conductive bending structure 6 is d4. The thickness d3 of the first conductive foil 4 is less than or equal to the thickness d4 of the conductive bending structure 6.

[0073] The solar cell 10 provided in the present application includes a cell piece 1, a plurality of first solder strips 21 and a plurality of second solder strips 22, a plurality of insulating strips 3, a first conductive foil 4, a packaging cover plate 5, and a conductive bending structure 6. The plurality of first solder strips 21 and the plurality of second solder strips 22, the plurality of insulating strips 3, the conductive foil 4, and the packaging cover plate 5 are sequentially arranged on the back surface of the cell piece 1. The packaging cover plate 5 is provided with an opening 51, and the conductive bending structure 6 includes a first portion 61 and a second portion 62, the first portion 61 is electrically connected with the first conductive foil 4, and the second portion 62 is led out of the packaging cover plate 5 through the opening 51. Since the thickness d3 of the first conductive foil 4 is less than or equal to the thickness d4 of the conductive bending structure 6, the overall thickness of the solar cell 10 is reduced, thereby reducing the risk of hidden cracks or broken pieces of the solar cell 10.

[0074] Figure 2 For Figure 2 the connection diagram of the conductive bending structure and the first conductive foil.

[0075] Referring to Figure 8 and Figures 6-8 , the first portion 61 partially overlaps the first conductive foil 4. For example, the length L5 of the portion of the first portion 61 that does not overlap the first conductive foil 4 is less than or equal to 4 mm. By setting L5, the bending line (the junction line between the first portion 61 and the second portion 62) of the conductive bending structure (bus bar) 6 is not adjacent to the first conductive foil 4, thereby providing a margin for the bending of the conductive bending structure (bus bar) 6.

[0076] The thickness of the solar cell 10 in the region where the first portion 61 overlaps with the first conductive foil 4 is thicker than the thickness of the solar cell 10 in other regions. The opening 51 exposes the portion of the first portion 61 that overlaps with the first conductive foil 4. Since the opening 51 exposes the overlapping portion, the thickness of the film layer under the encapsulation cover plate 5 is uniform during the lamination of the solar cell 10, thereby reducing the risk of cracking or chipping of the solar cell 10 during the lamination.

[0077] In some embodiments, referring to Figure 6 , the conductive bending structure 6 is a busbar, and the thickness d3 of the first conductive foil 4 is less than the thickness d4 of the busbar. For example, the ratio of the thickness d4 of the conductive bending structure 6 to the thickness d3 of the first conductive foil 4 is in the range of 1.67-20, for example, the value of d4:d3 can be 1.67, 5, 10, 15, or 20. By setting the thickness d3 of the conductive foil 4 and the thickness d4 of the conductive bending structure 6 in the range of 1.67-20, the overall thickness of the solar cell 10 can be effectively reduced, thereby reducing the risk of cracking or chipping of the solar cell 10.

[0078] For example, referring to Figure 7 (2) and Figure 2 (2), the thickness d3 of the first conductive foil 4 is in the range of 10 μm-60 μm, for example, d3 can be 10 μm, 20 μm, 35 μm, 45 μm, or 60 μm. The thickness d4 of the conductive bending structure 6 is in the range of 0.1 mm-0.2 mm.

[0079] In some embodiments, referring to Figure 8 , the material of the first conductive foil 4 is different from the material of the busbar. For example, the material of the first conductive foil 4 can be a conductive metal such as copper, aluminum, copper-aluminum composite, etc., and the material of the busbar can be a metal with a copper core and a tin-lead alloy coating. By setting the first conductive foil 4 and the busbar to be made of different materials, a conductive metal with better ductility and conductivity and lower cost can be selected as the material of the first conductive foil 4, thereby improving the current collecting capacity of the first conductive foil 4 and reducing the manufacturing cost of the solar cell 10.

[0080] In some embodiments, referring to Figure 2 , the first portion 61 and the first conductive foil 4 can be welded. For example, flux can be applied to the contact surface between the first portion 61 and the first conductive foil 4, and then an electric soldering iron can be used for welding; or the first portion 61 and the first conductive foil 4 can be overlapped without additional flux, and ultrasonic welding or laser welding can be used. The welding method is cost-effective and easy to operate. Alternatively, the first portion 61 and the first conductive foil 4 can also be electrically connected by conductive glue. For example, the material of the conductive glue includes conductive glue or solder paste.

[0081] In some embodiments, referring to Figure 2 , the ratio of the size D of the opening 51 to the width W3 of the conductive bent structure 6 is greater than or equal to 1.2. The present application does not limit the shape of the opening 51, for example, the opening 51 can be a circular opening, the opening 51 has a diameter D, that is, D:W3≥1.2. For example, D=12mm, then W3≤10mm. By setting D:W3≥1.2, the second part 62 can pass through the opening 51 more easily, thereby reducing the difficulty of the second part 62 passing through the opening 51.

[0082] In some embodiments, referring to Figure 8 and Figure 2 , the width W2 of the first conductive foil 4 is greater than the width W3 of the conductive bent structure 6. For example, the ratio of the width W2 of the conductive foil 4 to the width W3 of the conductive bent structure 6 ranges from 1.67 to 105, for example, the width W2 of the conductive foil 4 ranges from 16.7mm to 210mm, for example, W2 can be 16.7mm, 50mm, 100mm, 150mm or 210mm. The width W3 of the conductive bent structure 6 ranges from 2mm to 10mm. By setting the first conductive foil 4 with a wider width, the area of the first conductive foil 4 covering the first solder strip 21 can be increased, thereby increasing the current collecting capacity of the first conductive foil 4, and thereby improving the current transmission capacity of the first conductive foil 4.

[0083] In some embodiments, referring to Figure 8 and Figure 12 , in the second direction Y parallel to the back surface, the cross-sectional area of the first conductive foil 4 is greater than or equal to the cross-sectional area of the conductive bent structure 6, the second direction Y intersects the first direction X, for example, the second direction Y is perpendicular to the first direction X. That is, the cross-sectional area of the first conductive foil 4 is greater than or equal to the cross-sectional area of the busbar, according to the formula R=ρL / S (ρ represents the resistivity of the resistance, which is determined by its own properties, L represents the length of the resistance, S represents the cross-sectional area of the resistance), it can be known that, compared with using a traditional busbar, the embodiments of the present application use a first conductive foil 4 with a larger cross-sectional area as a busbar assembly of the solar cell 10, which can reduce the resistance of the first conductive foil 4, thereby reducing the resistance loss of the solar cell 10, to improve the component power of the solar cell 10.

[0084] The present application also provides a preparation method of a solar cell, which is used for preparing the solar cell 10 as shown in Figure 9 , which is a preparation method of a solar cell provided by the embodiments of the present application; Figures 10-13 , which is a step diagram of the preparation method in Figure 9 . Figure 9

[0085] Referring to​Figure 10 The preparation method comprises the following steps S1-S5:

[0086] Step S1: referring to Figure 10 , a battery piece 1 is provided, the battery piece 1 comprising opposite front and back surfaces, Figure 11 The back surface of the battery piece 1 is shown in

[0087] Step S2: referring to Figure 11 , a plurality of first solder strips 21 and a plurality of second solder strips 22 are arranged on the back surface, the first solder strips 21 and the second solder strips 22 being arranged alternately along a first direction X parallel to the back surface.

[0088] Exemplarily, referring to Figure 11 , a plurality of first main grids 71 and a plurality of second main grids 72 are further arranged on the back surface, the first main grids 71 and the second main grids 72 being arranged alternately along the first direction X. Exemplarily, the material of the plurality of first main grids 71 and the material of the plurality of second main grids 72 can be silver paste. The polarity of the first main grids 71 and the second main grids 72 is different, exemplarily, the first main grids 71 are positive main grids and the second main grids 72 are negative main grids, or the first main grids 71 are negative main grids and the second main grids 72 are positive main grids. Embodiments of the present application are described by taking the first main grids 71 as positive main grids and the second main grids 72 as negative main grids as an example.

[0089] The first solder strips 21 are located above the first main grids 71 and cover the first main grids 71, and the second solder strips 22 are located above the second main grids 72 and cover the second main grids 72, that is, the first solder strips 21 have positive electricity and the second solder strips 22 have negative electricity. Exemplarily, tin paste points are arranged between the first solder strips 21 and the first main grids 71 and between the second solder strips 22 and the second main grids 72, and the electrical connection between the main grids and the solder strips is realized through the tin paste points.

[0090] Exemplarily, continuing to refer to Figure 12 , a plurality of first auxiliary grids 81 and a plurality of second auxiliary grids 82 are further arranged on the back surface, the first auxiliary grids 81 and the second auxiliary grids 82 being arranged alternately along a second direction parallel to the back surface. The first direction and the second direction intersect, exemplarily, the first direction and the second direction are perpendicular, the first direction is direction X, and the second direction is direction Y, that is, the plurality of first auxiliary grids 81 and the plurality of second auxiliary grids 82 are arranged perpendicularly to the plurality of first main grids 71 and the plurality of second main grids 72.

[0091] The polarity of the first auxiliary grids 81 and the second auxiliary grids 82 is different, exemplarily, the first auxiliary grids 81 are positive auxiliary grids and the second auxiliary grids 82 are negative auxiliary grids, or the first auxiliary grids 81 are negative auxiliary grids and the second auxiliary grids 82 are positive auxiliary grids. Embodiments of the present application are described by taking the first auxiliary grids 81 as positive auxiliary grids and the second auxiliary grids 82 as negative auxiliary grids as an example.

[0092] Step S3: see Figure 12 A plurality of insulating strips 3 are arranged on the back surface, the plurality of insulating strips 3 are arranged along the first direction X, and one insulating strip 3 is arranged on the side of one second solder strip 22 away from the battery piece 1. The insulating strip 3 is used to insulate the second solder strip 22 and the metal conductive layer above the second solder strip 22.

[0093] For example, see Figure 12 The contact between the main grid and the auxiliary grid of the same polarity realizes electrical connection, and the insulating layer 31 is arranged between the main grid and the auxiliary grid of different polarities. For example, the insulating layer 31 can be any one of insulating glue or insulating block. In the embodiment of the application, the first main grid 71 is in direct contact with the first auxiliary grid 81, the insulating layer 31 is arranged between the first main grid 71 and the second auxiliary grid 82, the second main grid 72 is in direct contact with the second auxiliary grid 82, and the insulating layer 31 is arranged between the second main grid 72 and the first auxiliary grid 81.

[0094] For example, see Figure 13 The insulating glue 30 is printed between the first main grid 71 and the second main grid 72 to cover the auxiliary grid of the same polarity as the second solder strip 22, that is, the second auxiliary grid 82, so as to realize the insulation between the second auxiliary grid 82 and the second solder strip 22 with negative electricity and the first conductive foil 4 with positive electricity. In this case, the width W1 of the insulating strip 3 only needs to cover the width d1 of the second solder strip 22, for example, W1>d1+2mm. The distance between the first main grid 71 and the second main grid 72 is x, and the distance d2 between the adjacent two insulating strips 3 is 2x-W1.

[0095] Step S4: see Figure 2 The first conductive foil 4 and the conductive bending structure 6 are arranged on the side of the insulating strip 3 away from the battery piece 1, and the first conductive foil 4 is connected with the plurality of first solder strips 21, that is, the first conductive foil 4 is connected with the solder strip with positive electricity, so as to collect positive electricity on the first conductive foil 4.

[0096] Step S5: see Figure 2 The packaging cover plate 5 is arranged on the side of the first conductive foil 4 away from the battery piece 2, so as to form the solar cell 10. The packaging cover plate 5 is provided with an opening 51, and the material of the packaging cover plate 5 is glass.

[0097] For example, see Figure 2 The conductive bending structure 6 is bent to form a first part 61 and a second part 62, the first part 61 is electrically connected with the first conductive foil 4, and the second part 62 is led out to the outside of the packaging cover plate 5 through the opening 51. The thickness of the first conductive foil 4 is less than or equal to the thickness of the conductive bending structure 61.

[0098] For example, see Figure 13The ratio of the size D of the opening 51 to the width W3 of the conductive bent structure 6 is greater than or equal to 1.2. The present application does not limit the shape of the opening 51. For example, the opening 51 can be a circular opening, and the opening 51 has a diameter D, i.e., D:W3≥1.2. For example, D=12mm, and W3≤10mm. By setting D:W3≥1.2, the second part 62 can pass through the opening 51 more easily, thereby reducing the difficulty of the second part 62 passing through the opening 51.

[0099] The preparation method provided by the present application sets a plurality of first solder strips 21 and a plurality of second solder strips 22 on the back of the battery piece 1, sets a plurality of insulating strips 3 on the back, one insulating strip 3 is set on the side away from the battery piece 1 of one second solder strip 22, so as to insulate the second solder strip 22 from the metal conductive layer located above the second solder strip 22. The first conductive foil 4 and the conductive bent structure 6 are set on the side away from the battery piece 1 of the insulating strip 3, and the first conductive foil 4 is connected with the plurality of first solder strips 21, i.e., the first conductive foil 4 functions as a current collector. The packaging cover plate 5 is set on the side away from the battery piece 2 of the first conductive foil 4, and the packaging cover plate 5 is provided with an opening 51.

[0100] The conductive bent structure 6 is bent to form a first part 61 and a second part 62, the first part 61 is electrically connected with the first conductive foil 4, and the second part 62 passes through the opening 51 and is led out to the outside of the packaging cover plate 5, and the thickness of the first conductive foil 4 is less than or equal to the thickness of the conductive bent structure 61. By setting the first conductive foil 4 with a thinner thickness, the overall thickness of the solar cell 10 is reduced, the risk of stress being too large at the first conductive foil 4 and the risk of solder joint failure are reduced, thereby reducing the risk of solar cell 10 cracking or chipping.

[0101] In some embodiments, referring to Figure 2 The first conductive foil 4 and the conductive bent structure 6 are set on the back, which includes connecting the first conductive foil 4 with the plurality of first solder strips 21 by using a bonding process. The first conductive foil 4 is bonded with the plurality of first solder strips 21 through a metal interconnection layer (or conductive adhesive). For example, the material of the metal interconnection layer can be tin paste, and the material of the conductive adhesive can be pressure-sensitive adhesive tape.

[0102] Referring to Figure 14After the encapsulation cover plate 5 is arranged, the above preparation method further comprises electrically connecting the first conductive foil 6 and the plurality of first solder strips 21 by using a lamination process. The first conductive foil 4 is electrically connected to the plurality of first solder strips 21 through a metal interconnection layer (or conductive glue), that is, the first conductive foil 4 does not need to be directly soldered to the first solder strips 21, thereby reducing the high temperature during soldering of the first conductive foil 4 and the first solder strips 21 and the influence on the main grid located below the solder strips. Moreover, there is no solder joint between the first conductive foil 4 and the first solder strips 21, thereby reducing the damage of the solder joint to the battery piece 1. In the case that the first conductive foil 4 is pulled by an external force, the stress is concentrated at this position. Since there is no solder joint between the first conductive foil 4 and the first solder strips 21, the alloy layer between the solder paste point and the main grid is less likely to be broken and detached, thereby increasing the firmness and reliability of the solder paste point.

[0103] Figure 13 The step diagram for forming the first conductive foil and the conductive bent structure provided by the embodiments of the present application.

[0104] In some embodiments, referring to Figure 14 , the conductive bent structure 6 is a bus bar. Before the first conductive foil 4 and the conductive bent structure 6 are arranged on the back surface, the above preparation method further comprises, referring to Figure 14 , connecting the bus bar to the first conductive foil 4 and bending the bus bar to form a first portion 61 and a second portion 62, the first portion 61 being electrically connected to the first conductive foil 4. That is, the first conductive foil 4 and the conductive bent structure 6 are connected and the conductive bent structure 6 is bent in advance, and then the whole is arranged on the back surface.

[0105] For example, referring to Figure 15 , the first portion 61 and the first conductive foil 4 are overlapped together without additional flux, and are welded by using ultrasonic welding or laser welding. The welding method is low in cost and easy to operate. Alternatively, the first portion 61 and the first conductive foil 4 are electrically connected by using conductive glue. For example, the material of the conductive glue includes conductive glue or solder paste.

[0106] In another aspect, the embodiments of the present application also provide another solar cell, Figure 15 The structure diagram of the solar cell provided by the embodiments of the present application.

[0107] Referring to Figure 15 , the solar cell 10 comprises a battery piece 1, a plurality of first solder strips 21 and a plurality of second solder strips 22, a plurality of insulating strips 3, a first conductive foil 4, an encapsulation cover plate 5 and a conductive bent structure 6.

[0108] The battery piece 1 comprises opposite front and back surfaces, Figure 15The back surface of the cell sheet 1 is shown in FIG. 1. A plurality of first solder strips 21 and a plurality of second solder strips 22 are disposed on the back surface, and the first solder strips 21 and the second solder strips 22 are arranged alternately along a first direction (direction X) parallel to the back surface.

[0109] The solar cell 10 further includes a plurality of first main grids 71 and a plurality of second main grids 72, which are arranged alternately along the first direction X. The material of the plurality of first main grids 71 and the material of the plurality of second main grids 72 can be silver paste, for example. The polarity of the first main grids 71 and the second main grids 72 is different, and the first main grids 71 are positive main grids and the second main grids 72 are negative main grids, or the first main grids 71 are negative main grids and the second main grids 72 are positive main grids, for example. The embodiment of the present application is described by taking the first main grids 71 as positive main grids and the second main grids 72 as negative main grids as an example.

[0110] The first solder strips 21 are located above the first main grids 71 and cover the first main grids 71, and the second solder strips 22 are located above the second main grids 72 and cover the second main grids 72, that is, the first solder strips 21 are positively charged and the second solder strips 22 are negatively charged. Solder paste points are disposed between the first solder strips 21 and the first main grids 71 and between the second solder strips 22 and the second main grids 72, for example, to realize electrical connection between the main grids and the solder strips.

[0111] A plurality of insulating strips 3 are arranged along the first direction X, and one insulating strip 3 is disposed on the side of one second solder strip 22 away from the cell sheet 1. The insulating strip 3 is used to insulate the second solder strip 22 from the first conductive foil 4. The first conductive foil 4 is disposed on the side of the insulating strip 3 away from the cell sheet 1, and the first conductive foil 4 is electrically connected to the plurality of first solder strips 21, that is, the first conductive foil 4 is electrically connected to the positively charged solder strips to collect positive electricity on the first conductive foil 4.

[0112] For example, continuing to refer to Figure 15 , the first conductive foil 4 is electrically connected to the plurality of first solder strips 21 through a metal interconnection layer (or conductive adhesive). The material of the metal interconnection layer can be solder paste, and the material of the conductive adhesive can be pressure-sensitive adhesive tape, for example. The first conductive foil 4 is electrically connected to the plurality of first solder strips 21 through the metal interconnection layer (or conductive adhesive), that is, the first conductive foil 4 does not need to be directly soldered to the first solder strips 21, thereby reducing the high temperature during soldering of the first conductive foil 4 and the first solder strips 21 and the influence on the main grids located below the solder strips. Moreover, there is no solder joint generated by direct soldering of the first conductive foil 4 and the first solder strips 21, thereby reducing the damage of the solder joint to the cell sheet 1. In the case that the first conductive foil 4 is pulled by external force, the stress is concentrated at this position. Since there is no solder joint between the first conductive foil 4 and the first solder strips 21, the alloy layer between the solder paste points 90 and the main grids is less likely to break and fail, and the soldering is less likely to be detached, thereby improving the firmness and reliability of the solder paste points.

[0113] Referring to Figure 15 The solar cell 10 further comprises a plurality of first sub-grids 81 and a plurality of second sub-grids 82, which are arranged alternately along a second direction parallel to the back surface. The first direction intersects the second direction, and in an example, the first direction is perpendicular to the second direction. The first direction is direction X, and the second direction is direction Y, i.e., the plurality of first sub-grids 81 and the plurality of second sub-grids 82 are arranged perpendicularly to the plurality of first main grids 71 and the plurality of second main grids 72.

[0114] The first sub-grids 81 and the second sub-grids 82 have different polarities. In an example, the first sub-grids 81 are positive sub-grids, and the second sub-grids 82 are negative sub-grids, or the first sub-grids 81 are negative sub-grids, and the second sub-grids 82 are positive sub-grids. Embodiments of the present application are described by taking the first sub-grids 81 as positive sub-grids and the second sub-grids 82 as negative sub-grids as an example.

[0115] In an example, continuing to refer to Figure 15 The contact between the main grids and the sub-grids of the same polarity realizes electrical connection, and the main grids and the sub-grids of different polarities are provided with an insulating layer. The insulating layer can be any one of insulating glue or an insulating block. In embodiments of the present application, the first main grids 71 are in direct contact with the first sub-grids 81, the first main grids 71 and the second sub-grids 82 are provided with an insulating layer 31, the second main grids 72 are in direct contact with the second sub-grids 82, and the second main grids 72 and the first sub-grids 81 are provided with an insulating layer.

[0116] Continuing to refer to Figure 16 The conductive bending structure 6 is bent to form a first portion 61 and a second portion 62. The first portion 61 is electrically connected to the conductive foil 4, and the second portion 62 is led out to the outside of the packaging cover plate 5 through the opening 51 and is electrically connected to the junction box.

[0117] Figure 15 FIG. 4 is a schematic view of the connection between the conductive bending structure and the first conductive foil in Figure 15

[0118] In some embodiments, referring to Figure 16 and Figure 15 ​The first part 61 comprises the second conductive foil 42, and the second part 62 comprises the third conductive foil 43 and the busbar 44. The thicknesses of the first conductive foil 4, the second conductive foil 42 and the third conductive foil 43 are equal and smaller than the thickness of the busbar 44. It can be understood that the conductive layer arranged on the back of the cell 1 for collecting current and the bending part of the conductive bending structure 6 are both made of the conductive foil with thin thickness, so that the film layer thickness under the encapsulation cover plate 5 is uniform and thinner, thereby reducing the risk of hidden cracking or cracking of the solar cell 10 in the lamination process. Moreover, the second conductive foil 42 and the third conductive foil 43 have better bending performance due to their thinner thickness, the bending performance of the bending area of the conductive bending structure 6 is improved by using the conductive foil in the bending area, thereby improving the hidden cracking of the cell 1 at the bending part.

[0119] In some embodiments, referring to Figure 16 and Figure 16 The first conductive foil 4, the second conductive foil 42 and the third conductive foil 43 are made of the same material and are integrally arranged. The materials of the first conductive foil 4, the second conductive foil 42 and the third conductive foil 43 are different from the material of the busbar 44. For example, the materials of the first conductive foil 4, the second conductive foil 42 and the third conductive foil 43 can be any one or more alloys of gold, silver, copper, aluminum, tin, etc., and the outer layer can be tinned or not tinned. The material of the busbar 44 can be a metal with a copper inner core and a tinned lead alloy outer surface. By arranging the conductive foils and the busbar 44 made of different materials, a conductive metal with better ductility and conductivity and lower cost can be selected as the material of the first conductive foil 4, the second conductive foil 42 and the third conductive foil 43, thereby improving the current collecting capacity of the first conductive foil 4 and the conductivity of the second conductive foil 42 and the third conductive foil 43, and reducing the preparation cost of the solar cell 10.

[0120] In some embodiments, referring to Figure 16 In the second part 62, the third conductive foil 43 is welded with the busbar 44. Alternatively, the third conductive foil 43 and the busbar 44 can be electrically connected by conductive glue. For example, flux is applied to the contact surface of the third conductive foil 43 and the busbar 44, and then the third conductive foil 43 and the busbar 44 are welded by using an electric soldering iron. Alternatively, the third conductive foil 43 and the busbar 44 are overlapped together without additional flux, and are welded by using ultrasonic welding or laser welding. The welding method is low in cost and easy to operate. Alternatively, the third conductive foil 43 and the busbar 44 can also be electrically connected by conductive glue. For example, the material of the conductive glue includes conductive glue or tin paste.

[0121] For example, continuing to refer to Figure 15, the length L5 of the second conductive foil 42 is less than or equal to 4 mm, the bending line (the junction line of the second conductive foil 42 and the third conductive foil 43) of the conductive bending structure 6 is not adjacent to the first conductive foil 4, so as to provide a margin for the bending of the conductive bending structure 6. The third conductive foil 43 comprises two parts, the length L6 of the first part is greater than or equal to 1 mm, the length L7 of the second part is in the range of 4 mm to 15 mm, the busbar 44 also comprises two parts, the length L8 of the first part is greater than or equal to 5 mm, the first part is used for electrical connection with the junction box, the length of the second part is L7, and the second part of the third conductive foil 43 is welded with the second part of the busbar 44.

[0122] In some embodiments, referring to Figure 15 , the ratio of the size D of the opening 51 to the width W3 of the conductive bending structure 6 is greater than or equal to 1.2. The shape of the opening 51 is not limited in the present application. For example, the opening 51 can be a circular opening, and the opening 51 has a diameter D, i.e., D:W3≥1.2. For example, D=12 mm, and W3≤10 mm. By setting D:W3≥1.2, the second part 62 can pass through the opening 51 more easily, thereby reducing the difficulty of the second part 62 passing through the opening 51.

[0123] In some embodiments, referring to Figure 16 and Figure 15 , the width W2 of the first conductive foil 4 is greater than the width W3 of the conductive bending structure 6. For example, the ratio of the width W2 of the conductive foil 4 to the width W3 of the conductive bending structure 6 is in the range of 1.67 to 105, for example, the width W2 of the conductive foil 4 is in the range of 16.7 mm to 210 mm, for example, W2 can be 16.7 mm, 50 mm, 100 mm, 150 mm or 210 mm. The width W3 of the conductive bending structure 6 is in the range of 2 mm to 10 mm. By setting the first conductive foil 4 with a wider width, the area of the first conductive foil 4 covering the first solder strip 21 can be increased, thereby increasing the current collection capacity of the first conductive foil 4, and thereby improving the current transmission capacity of the first conductive foil 4.

[0124] In some embodiments, referring to Figure 16 and Figure 15, along a second direction Y parallel to the back surface, the cross-sectional area of the first conductive foil 4 is greater than or equal to the cross-sectional area of the conductive bending structure 6, the second direction Y intersects the first direction X, and the second direction Y is perpendicular to the first direction X, for example. That is, the cross-sectional area of the first conductive foil 4 is greater than or equal to the cross-sectional area of the bus bar, and according to the calculation formula R = pL / S (p represents the resistivity of the resistance, which is determined by its own properties, L represents the length of the resistance, and S represents the cross-sectional area of the resistance), it can be known that, compared with using a traditional bus bar, the embodiment of the present application can reduce the resistance of the first conductive foil 4 by using the first conductive foil 4 with a larger cross-sectional area as the bus assembly of the solar cell 10, thereby reducing the resistance loss of the solar cell 10 and improving the component power of the solar cell 10.

[0125] In another aspect, the embodiment of the present application also provides another preparation method of a solar cell, which is used for preparing a solar cell as shown in Figure 17 . Figure 9 . Figure 9 .

[0126] Referring to Figure 10 , the preparation method comprises the following steps S1-S5:

[0127] Step S1: referring to Figure 10 , a cell piece 1 is provided, the cell piece 1 comprises opposite front and back surfaces, Figure 11 , the back surface of the cell piece 1 is shown in

[0128] Step S2: referring to Figure 11 , a plurality of first solder strips 21 and a plurality of second solder strips 22 are arranged on the back surface, and the first solder strips 21 and the second solder strips 22 are arranged alternately along a first direction X parallel to the back surface.

[0129] For example, referring to Figure 11 , a plurality of first main grids 71 and a plurality of second main grids 72 are further arranged on the back surface, and the first main grids 71 and the second main grids 72 are arranged alternately along the first direction X. For example, the material of the plurality of first main grids 71 and the material of the plurality of second main grids 72 can be silver paste. The polarity of the first main grid 71 and the second main grid 72 is different, for example, the first main grid 71 is a positive main grid, and the second main grid 72 is a negative main grid, or the first main grid 71 is a negative main grid, and the second main grid 72 is a positive main grid. The embodiment of the present application takes the first main grid 71 as the positive main grid and the second main grid 72 as the negative main grid as an example for description.

[0130] The first solder strip 21 is located above and covers the first main grid 71, and the second solder strip 22 is located above and covers the second main grid 72, that is, the first solder strip 21 has positive electricity, and the second solder strip 22 has negative electricity. Exemplarily, tin paste points are arranged between the first solder strip 21 and the first main grid 71, and between the second solder strip 22 and the second main grid 72, and the electrical connection between the main grid and the solder strip is realized through the tin paste points.

[0131] Exemplarily, continuing to refer to Figure 12 A plurality of first sub-grids 81 and a plurality of second sub-grids 82 are also arranged on the back surface, and the first sub-grids 81 and the second sub-grids 82 are arranged alternately along a second direction parallel to the back surface. The first direction intersects the second direction, and exemplarily, the first direction is perpendicular to the second direction, the first direction is direction X, and the second direction is direction Y, that is, the plurality of first sub-grids 81 and the plurality of second sub-grids 82 are arranged perpendicularly to the plurality of first main grids 71 and the plurality of second main grids 72.

[0132] The polarities of the first sub-grids 81 and the second sub-grids 82 are different, and exemplarily, the first sub-grids 81 are positive sub-grids, and the second sub-grids 82 are negative sub-grids, or the first sub-grids 81 are negative sub-grids, and the second sub-grids 82 are positive sub-grids. Embodiments of the present application take the first sub-grids 81 as positive sub-grids and the second sub-grids 82 as negative sub-grids as an example for description.

[0133] Step S3: referring to Figure 12 A plurality of insulating strips 3 are arranged on the back surface, and the plurality of insulating strips 3 are arranged along the first direction X, and one insulating strip 3 is arranged on one side of the second solder strip 22 away from the battery piece 1. The insulating strip 3 is used to insulate the second solder strip 22 from the metal conductive layer located above the second solder strip 22.

[0134] Exemplarily, referring to Figure 12 The contact between the main grids and the sub-grids with the same polarity realizes electrical connection, and the insulating layer 31 is arranged between the main grids and the sub-grids with different polarities. Exemplarily, the insulating layer 31 can be any one of insulating glue or an insulating block. In the embodiments of the present application, the first main grid 71 directly contacts the first sub-grid 81, the insulating layer 31 is arranged between the first main grid 71 and the second sub-grid 82, the second main grid 72 directly contacts the second sub-grid 82, and the insulating layer 31 is arranged between the second main grid 72 and the first sub-grid 81.

[0135] Exemplarily, continuing to refer to Figure 17, the insulating strip 3 is printed with insulating glue 30 between the first main grid 71 and the second main grid 72 to cover the sub-grid of the same polarity as the second solder strip 22, i.e. the second sub-grid 82, so as to realize the insulation of the second sub-grid 82 and the second solder strip 22 with negative electricity and the first conductive foil 4 with positive electricity. In this case, the width W1 of the insulating strip 3 only needs to cover the width d1 of the second solder strip 22, for example, W1>d1+2mm. The distance between the first main grid 71 and the second main grid 72 is x, and the distance d2 between the adjacent two insulating strips 3 is d2=2x-W1.

[0136] Step S4: refer to Figure 15 The first conductive foil 4 and the conductive bending structure 6 are arranged on the back surface, the first conductive foil 4 and the conductive bending structure 6 are arranged on the side of the insulating strip 3 away from the battery piece 1, and the first conductive foil 4 is connected with the plurality of first solder strips 21, i.e. the first conductive foil 4 is connected with the positive solder strip, and the positive electricity is collected in the first conductive foil 4.

[0137] Step S5: refer to Figure 15 The packaging cover plate 5 is arranged on the side of the first conductive foil 4 away from the battery piece 2 to form the solar cell 10. The packaging cover plate 5 is provided with an opening 51. The material of the packaging cover plate 5 is glass, for example.

[0138] Among them, refer to Figure 15 The conductive bending structure 6 is bent to form a first part 61 and a second part 62, the first part 61 is electrically connected with the first conductive foil 4, and the second part 62 is led out to the outside of the packaging cover plate 5 through the opening 51, and the thickness of the first conductive foil 4 is less than or equal to the thickness of the conductive bending structure 61.

[0139] For example, continue to refer to Figure 17 The ratio of the size D of the opening 51 to the width W3 of the conductive bending structure 6 is greater than or equal to 1.2. The shape of the opening 51 is not limited in the application, for example, the opening 51 can be a circular opening, the opening 51 has a diameter D, i.e. D:W3≥1.2. For example, D=12mm, then W3≤10mm. By setting D:W3≥1.2, the second part 62 can pass through the opening 51 more easily, thereby reducing the difficulty of the second part 62 passing through the opening 51.

[0140] The preparation method provided in the present application sets a plurality of first solder strips 21 and a plurality of second solder strips 22 on the back of the battery piece 1, sets a plurality of insulating strips 3 on the back, one insulating strip 3 is set on the side of one second solder strip 22 away from the battery piece 1, so as to insulate the second solder strip 22 from the metal conductive layer above the second solder strip 22. The first conductive foil 4 and the conductive bending structure 6 are set on the side of the insulating strip 3 away from the battery piece 1, and the first conductive foil 4 is connected with the plurality of first solder strips 21, that is, the first conductive foil 4 functions as a current collector. The packaging cover plate 5 is set on the side of the first conductive foil 4 away from the battery piece 2, and the packaging cover plate 5 is provided with an opening 51.

[0141] The conductive bending structure 6 is bent to form a first part 61 and a second part 62, the first part 61 is electrically connected with the first conductive foil 4, and the second part 62 is led out to the outside of the packaging cover plate 5 through the opening 51, and the thickness of the first conductive foil 4 is less than or equal to the thickness of the conductive bending structure 61. By setting the first conductive foil 4 with a thinner thickness, the overall thickness of the solar cell 10 is reduced, the risk of stress being too large at the first conductive foil 4 and the risk of solder joint failure are reduced, thereby reducing the risk of the solar cell 10 being cracked or broken.

[0142] In some embodiments, referring to Figure 15 The first conductive foil 4 and the conductive bending structure 6 are set on the back, including connecting the first conductive foil 4 with the plurality of first solder strips 21 by using a bonding process. The first conductive foil 4 is bonded with the plurality of first solder strips 21 through a metal interconnection layer (or conductive adhesive). For example, the material of the metal interconnection layer can be tin paste, and the material of the conductive adhesive can be pressure-sensitive adhesive tape.

[0143] Referring to Figure 18 After the packaging cover plate 5 is set, the above preparation method further includes electrically connecting the first conductive foil 6 with the plurality of first solder strips 21 by using a laminating process. The first conductive foil 4 is electrically connected with the plurality of first solder strips 21 through a metal interconnection layer (or conductive adhesive), that is, the first conductive foil 4 does not need to be directly soldered with the first solder strips 21, thereby reducing the high temperature when the first conductive foil 4 is soldered with the first solder strips 21, and reducing the influence on the main grid below the solder strip. Moreover, the first conductive foil 4 does not have a solder joint generated by being directly soldered with the first solder strips 21, thereby reducing the damage of the solder joint to the battery piece 1. In the case that the first conductive foil 4 is pulled by external force, the stress is concentrated at this position, and since the first conductive foil 4 does not have a solder joint with the first solder strips 21, the alloy layer between the tin paste point and the main grid is less likely to be broken and detached, thereby increasing the firmness and reliability of the tin paste point.

[0144] Figure 19 And Figure 15 The steps of forming the first conductive foil and the conductive bending structure provided in the embodiments of the present application are shown in the following figures.

[0145] In some embodiments, referring to Figure 18 , the first part 61 comprises the second conductive foil 42, and the second part 62 comprises the third conductive foil 43 and the bus bar 44. Before the first conductive foil 4 and the conductive bending structure 6 are arranged on the back surface, the above manufacturing method further comprises the following steps S401-S403:

[0146] Step S401: referring to Figure 19 , a conductive foil is formed, which comprises the first conductive foil 4, the second conductive foil 42 and the third conductive foil 43 arranged integrally.

[0147] Step S402: referring to Figure 16 , the bus bar 44 is connected with the third conductive foil 43 to form the conductive structure 40.

[0148] Step S403: referring to Figure 16 , the conductive structure 40 is bent along the joint line L of the second conductive foil 42 and the third conductive foil 43 to form the first conductive foil 4 and the conductive bending structure 6 arranged on the back surface in the above step S4. That is, the first conductive foil 4 and the conductive bending structure 6 are connected and the conductive bending structure 6 is bent in advance, and then the whole is arranged on the back surface.

[0149] Illustratively, referring to ​ , the soldering flux is applied on the contact surface of the third conductive foil 43 and the bus bar 44, and then the electric soldering iron is used for welding; or the third conductive foil 43 and the bus bar 44 are overlapped together, without additional soldering flux, and the ultrasonic welding or laser welding is used. The welding method is low in cost and easy to operate. Alternatively, the conductive glue is applied on the contact surface of the third conductive foil 43 and the bus bar 44 to electrically connect them. Illustratively, the material of the conductive glue comprises conductive glue or tin paste.

[0150] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can think of changes or replacements within the technical scope disclosed by the present application, which shall be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A solar cell, characterized by, The battery piece comprises opposite front and back surfaces. A plurality of first and second solder strips are arranged on the back surface. The first and second solder strips are arranged alternately along a first direction parallel to the back surface. A plurality of insulating strips are arranged on the side of the second solder strip away from the battery piece. A first conductive foil is arranged on the side of the insulating strip away from the battery piece, and the first conductive foil is electrically connected with the plurality of first solder strips. An encapsulation cover plate is arranged on the side of the first conductive foil away from the battery piece, and the encapsulation cover plate is provided with an opening. A conductive bending structure is bent to form a first part and a second part, the first part is electrically connected with the first conductive foil, and the second part is led out to the outside of the encapsulation cover plate through the opening. The thickness of the first conductive foil is less than or equal to the thickness of the conductive bending structure. The first part and the first conductive foil partially overlap, and the opening exposes the overlapping part of the first part and the first conductive foil. The conductive bending structure is a bus bar, and the thickness of the first conductive foil is less than the thickness of the bus bar.

2. The solar cell according to claim 1, characterized in that, The ratio of the thickness of the bus bar to the thickness of the first conductive foil ranges from 1.67 to 20.

3. The solar cell according to claim 2, characterized in that, The material of the first conductive foil is different from the material of the bus bar.

4. The solar cell of claim 2, wherein The first part is welded with the first conductive foil, or the first part is electrically connected with the first conductive foil through conductive glue.

5. The solar cell of claim 2, wherein The first part comprises a second conductive foil, and the second part comprises a third conductive foil and a bus bar.

6. The solar cell of claim 1, wherein The thicknesses of the first conductive foil, the second conductive foil and the third conductive foil are equal and less than the thickness of the bus bar. The first conductive foil, the second conductive foil and the third conductive foil are integrally arranged and made of the same material.

7. The solar cell according to claim 6, characterized in that The material of the first conductive foil, the second conductive foil and the third conductive foil is different from the material of the bus bar. In the second part, the third conductive foil is welded with the bus bar, or the third conductive foil is electrically connected with the bus bar through conductive glue.

8. The solar cell of claim 7, wherein, Along a second direction parallel to the back surface, the width of the first conductive foil is greater than the width of the conductive bending structure, and the second direction intersects the first direction.

9. The solar cell according to any one of claims 1 to 8, wherein, The width of the first conductive foil ranges from 16.7 mm to 210 mm.

10. The solar cell of claim 9, wherein, The ratio of the size of the opening to the width of the conductive bending structure is greater than or equal to 1.

2.

11. The solar cell of claim 9, wherein, Along the second direction parallel to the back surface, the cross-sectional area of the first conductive foil is greater than or equal to the cross-sectional area of the conductive bending structure, and the second direction intersects the first direction.

12. The solar cell of claim 9, wherein, The first conductive foil is electrically connected with the first solder strip through a metal interconnection layer or conductive glue.

13. The solar cell of claim 1, wherein, The battery piece comprises opposite front and back surfaces.

14. A method of manufacturing a solar cell, characterized by, A plurality of first and second solder strips are arranged on the back surface. The first and second solder strips are arranged alternately along a first direction parallel to the back surface. A plurality of insulating strips are arranged on the side of the second solder strip away from the battery piece. ​ ​ A first conductive foil and a conductive bending structure are arranged on the back surface, the first conductive foil and the conductive bending structure are arranged on a side of the insulating strip away from the battery piece, and the first conductive foil is electrically connected with the plurality of first solder strips; A packaging cover plate is arranged on a side of the first conductive foil away from the battery piece, and the packaging cover plate is provided with an opening; The conductive bending structure is bent to form a first part and a second part, the first part is electrically connected with the first conductive foil, and the second part is led out to the outside of the packaging cover plate through the opening; the thickness of the first conductive foil is less than or equal to the thickness of the conductive bending structure; the first part partially overlaps with the first conductive foil, and the opening exposes the part where the first part overlaps with the first conductive foil.

15. The method of claim 14, wherein, The first conductive foil and the conductive bending structure are arranged on the back surface, including: The first conductive foil is connected with the plurality of first solder strips by using an adhesive process; After the packaging cover plate is arranged, the preparation method further includes: The first conductive foil is electrically connected with the plurality of first solder strips by using a laminating process.

16. The method of claim 14, wherein, The conductive bending structure is a bus bar, and before the first conductive foil and the conductive bending structure are arranged on the back surface, the preparation method further includes: The bus bar is connected with the first conductive foil; The bus bar is bent to form the first part and the second part, and the first part is electrically connected with the first conductive foil.

17. The preparation method according to claim 14, characterized in that, The first part includes a second conductive foil, the second part includes a third conductive foil and a bus bar, and before the first conductive foil and the conductive bending structure are arranged on the back surface, the preparation method further includes: A conductive foil is formed, the conductive foil includes the first conductive foil, the second conductive foil and the third conductive foil arranged integrally; The bus bar is connected with the third conductive foil to form a conductive structure; The conductive structure is bent along the junction line of the second conductive foil and the third conductive foil.

18. A photovoltaic module, characterized by, A plurality of solar cells as claimed in any one of claims 1-13 are included, and the plurality of solar cells are electrically connected.

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