Photovoltaic solar cell module

Abstract

The photovoltaic solar cell module comprises a cell piece and a welding strip, grid line electrodes are arranged on one face or two faces of the cell piece, the welding strip is correspondingly arranged on one face or two faces of the cell piece and welded to the corresponding grid line electrodes on the solar cell piece, and the welding strip and the solar cell piece are provided with connecting parts. In the extension direction of the central cross section of the connecting part of the grid line electrode and the solar cell piece, the connecting part is distributed below and on the two sides of the welding strip, the connecting part on the two sides comprises a first connecting area close to the welding strip and a second connecting area away from the welding strip, and the first connecting area and the second connecting area are adjacent to each other. The length of the second connecting area is larger than that of the first connecting area, and the thickness change of the second connecting area per unit length is smaller than that of the first connecting area per unit length. According to the photovoltaic solar cell module, after welding, the arrangement of the specific connecting part between the welding strip and the cell piece has larger welding tension, and the welding effect is good.

Description

Technical Field

[0001] The present application belongs to the technical field of solar cell processing and relates to a photovoltaic solar cell assembly. Background Art

[0002] In photovoltaic solar cell modules, the electrodes of solar cell grid lines are connected by welding ribbons. At present, cold welding and insufficient welding tension are technical problems that need to be solved in photovoltaic solar cell modules. At the same time, the repair of defective parts also wastes production time and increases production costs. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the present invention provides a photovoltaic solar cell assembly.

[0004] A photovoltaic solar cell assembly comprises a cell and a welding strip, wherein one side or both sides of the cell have a grid electrode, and the welding strip is correspondingly arranged on one side or both sides of the cell and welded to the corresponding grid electrode on the solar cell.

[0005] The welded welding ribbon and the solar cell have a connecting portion, and in the extension direction of the central cross-section of the connecting portion between the grid line electrode and the solar cell, the connecting portion is distributed below and on both sides of the welding ribbon, and the connecting portions on both sides include a first connecting area close to the welding ribbon and a second connecting area away from the welding ribbon, and the first connecting area and the second connecting area are adjacent to each other, wherein the length of the second connecting area is greater than the length of the first connecting area, and the thickness change per unit length of the second connecting area is less than the thickness change per unit length of the first connecting area.

[0006] In a photovoltaic solar cell assembly of one embodiment, in the central cross-sectional direction of the connection portion between the grid line electrode and the solar cell, the first connection area is a triangular area between the side of the welding strip and the surface of the cell, wherein the edge of the first connection area is close to a line, has an outward convex arc shape, or has an inward concave arc shape.

[0007] In a photovoltaic solar cell module according to an embodiment, in a central cross-sectional direction of a connection portion between the grid line electrode and the solar cell sheet, a length of the second connection region is more than twice a length of the first connection region.

[0008] In a photovoltaic solar cell assembly according to an embodiment, in a central cross-sectional direction of a connection portion between the grid line electrode and the solar cell sheet, an area of ​​the second connection region is smaller than an area of ​​the first connection region.

[0009] In a photovoltaic solar cell assembly according to an embodiment, when the total length of the connection portion between the grid line electrode and the solar cell sheet in the central cross-sectional direction is less than 1.5 mm, the length ratio of the second connection region to the first connection region is greater than 1.5.

[0010] In a photovoltaic solar cell assembly of one embodiment, the grid line electrode is thickened at the connection position where it contacts the welding strip, the thickened position is the thickened portion, the length of the thickened portion is greater than the width of the welding strip, and in the central cross-sectional direction of the connection portion between the grid line electrode and the solar cell sheet, the end of the second connection area is close to the edge of the thickened portion, located at the edge of the thickened portion or beyond the edge of the thickened portion.

[0011] In one embodiment of the photovoltaic solar cell assembly, the thickness of the welding ribbon is 0.1 to 0.5 mm.

[0012] In the photovoltaic solar cell assembly of one embodiment, the grid line electrode is a silver electrode or a tin electrode.

[0013] In a photovoltaic solar cell assembly according to one embodiment, before placing the soldering ribbon on the grid electrode, solder paste is applied to the connection position between the grid electrode and the soldering ribbon.

[0014] In a photovoltaic solar cell assembly of one embodiment, when welding is performed, the solar cell sheet, welding ribbon and other components are placed in a vacuum environment as a whole, and the vacuum degree is -10KPa to -80KPa.

[0015] In a photovoltaic solar cell assembly according to one embodiment, the cell is a busbar-less solar cell, and the welding strip is arranged perpendicular to the fine grid electrode.

[0016] In a photovoltaic solar cell assembly according to one embodiment, the cell is a main grid solar cell, and the welding strip is arranged in parallel above the main grid electrode and perpendicular to the fine grid electrode.

[0017] In one embodiment of a photovoltaic solar cell assembly, insulating glue is provided on the surface of the solar cell, and the welding strip and the solar cell have a connecting portion. In the central cross-sectional direction of the connecting portion between the grid electrode and the solar cell, the connecting portion is distributed below and on both sides of the welding strip, and the connecting portion on each side includes a first connecting area close to the welding strip, and a second connecting area extending away from the welding strip, and the first connecting area and the second connecting area are adjacent to each other, wherein the length of the second connecting area is greater than the length of the first connecting area, and the thickness variation per unit length of the second connecting area is less than the thickness variation per unit length of the first connecting area; the second connecting area is blocked by the insulating glue in the length direction and cannot be fully unfolded and formed.

[0018] Through the above technical solution, this application achieves the following technical effects.

[0019] The photovoltaic solar cell assembly of the present application has a specific connection portion between the welding ribbon and the solar cell after welding, which has a greater welding tension and a good welding effect, especially for the solar cell assembly without a main grid of the present embodiment, which has a good welding effect and solves the problems of cold welding and low welding tension of the solar cell assembly without a main grid in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic diagram of two adjacent solar cells and the welding strips connected thereto in a photovoltaic solar cell assembly according to an embodiment;

[0022] Figure 2 for Figure 1 Enlarged view of the circular schematic area;

[0023] Figure 3 for Figure 1 An enlarged view of the circular schematic area, wherein the electrode grid lines have a thickened portion;

[0024] Figures 4 to 6 for Figure 2 SEM image of the central cross section of the gate electrode and the connecting portion;

[0025] Figure 7 A schematic diagram of the structure in which a welding ribbon is placed on a solar cell with a main grid in a photovoltaic solar cell assembly according to an embodiment;

[0026] Figure 8 for Figure 7 SEM image of the central cross section of the gate electrode and the connecting portion;

[0027] In the figure, there are a solar cell 1, a soldering ribbon 2, an insulating adhesive 3, a grid line electrode 11, a main grid electrode 12, a thickened portion 111, and a soldering pad 13. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0030] Secondly, the present application is described in detail with reference to the schematic diagram. When describing the embodiments of the present application in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0031] A photovoltaic solar cell assembly comprises a cell sheet and a welding strip, wherein one side or both sides of the cell sheet have grid line electrodes, and the welding strip is correspondingly arranged on one side or both sides of the cell sheet and welded to the corresponding grid line electrodes on the solar cell sheet.

[0032] In one embodiment, the cell is a busbar-free solar cell, and the welding strip and the grid electrode welded thereto are arranged vertically. Figure 1 and Figure 2 Taking the back contact solar cell as an example, the gate electrode is arranged on the back of the cell, wherein: Figure 1 Two adjacent cells 1 and the welding strip 2 connected thereto in a photovoltaic solar cell assembly, Figure 1 The battery cell and the welding strip are schematically shown, but the details of the welding strip and the gate electrode are not shown. For example, the insulating glue provided at the corresponding position of the gate electrode to avoid short circuit is not shown in the figure. Figure 1 In the figure, the circular position is the welding point between the welding strip and a gate electrode and the position nearby. Figure 2 for Figure 1 Enlarged view of the circle-marked area. Figures 4 to 6 : is a SEM image of the central cross section of the gate line electrode and the connecting part.

[0033] The photovoltaic solar cell assembly of the present application has a specific connection portion between the welding ribbon and the solar cell after welding, which has a greater welding tension and a good welding effect, especially for the solar cell assembly without a main grid of the present embodiment, which has a good welding effect and solves the problems of cold welding and low welding tension of the solar cell assembly without a main grid in the prior art.

[0034] Specifically, the photovoltaic solar cell assembly of the present application has a connection portion between the welded welding ribbon and the solar cell, and in the central cross-sectional direction of the connection portion between the grid electrode and the solar cell, the connection portion is distributed below and on both sides of the welding ribbon, and the connection portions on both sides include a first connection area close to the welding ribbon and a second connection area extending away from the welding ribbon. The first connection area and the second connection area are adjacent, wherein the length of the second connection area is greater than the length of the first connection area, and the thickness change per unit length of the second connection area is less than the thickness change per unit length of the first connection area.

[0035] When the second connection area is not set, the starting point of the tensile failure of the connection part of the welding point between the welding ribbon and the battery cell is located at the intersection of the first connection area and the battery cell, and the tensile failure is quickly transmitted to the third connection area between the welding ribbon and the battery cell located below the welding ribbon, and the third connection area is partially torn until it is completely torn, so that the tension of the welding ribbon and the battery cell fails or is completely separated. In the embodiment of the present application, in addition to the first connection area close to the welding ribbon, a second connection area extending away from the welding ribbon is also set. The starting point of the tensile failure of the connection part of the welding point between the welding ribbon and the battery cell is located at the end of the contact area between the second connection area and the battery cell. The starting point of the tensile failure needs to travel a long distance to be transmitted to the intersection of the first connection area and the battery cell. When the battery cell after welding is subjected to a greater tensile force, it will affect the third connection area between the welding ribbon and the battery cell located below the welding ribbon, resulting in partial tearing or tearing of the third connection area. Setting the second connection area can effectively increase the tensile strength of the battery cell after welding. For specific comparative data, please refer to the specific embodiment below.

[0036] Setting the thickness variation per unit length of the second connection zone to be smaller than the thickness variation per unit length of the first connection zone is beneficial to ensuring that the thickness of the second connection zone is relatively uniform in the vertical direction, and the tensile failure strength of the second connection zone in the length direction is basically consistent without obvious tensile failure weak point areas, thereby ensuring that the second connection zone provides stable additional tensile strength.

[0037] It should be noted that the first connection area and the second connection area are adjacent to each other, which means that the first connection area and the second connection area are connected but not disconnected.

[0038] In some embodiments, the gate line electrode is thickened at the connection position where it contacts the solder strip, which is defined as a thickened portion for ease of description. The length of the thickened portion is greater than the width of the solder strip, see Figure 3 , is an enlarged view of the welding area between the welding strip and the grid line with the thickened portion and its vicinity. In such an embodiment, the end of the second connection area is close to the edge of the thickened portion, located at the edge of the thickened portion or beyond the edge of the thickened portion.

[0039] See also Figures 4 to 6 , Figures 4 to 6 is a SEM image of the central cross section of the gate electrode and the connecting portion. Figure 5 for Figure 4 The enlarged image on the left, Figure 6 for Figure 4 The enlarged view on the right. The first connection area is a triangular area between the side of the welding ribbon and the surface of the battery cell, and its connection edges (right angle sides) are respectively connected to the side of the welding ribbon and the surface of the battery cell, and its edge (hypotenuse) of the first connection area is close to a line. In some other embodiments, the edge of the first connection area has a convex arc shape or a concave arc shape.

[0040] The second connection area is in the shape of a long strip extending in the length direction, the thickness per unit length in the second connection area changes little, and the thickness suddenly decreases compared to the first connection area. Figure 4 In the figure, the adjacent position of the first connecting region and the second connecting region is shown in yellow circle.

[0041] The thickness variation per unit length of the first connection area is smaller than that of the second connection area. In other words, the edge of the first connection area is steeper, and the edge of the second connection area is flatter. It should be noted that the thickness variation per unit length is not necessarily based on a unit length of one millimeter or one micron, but can be one tenth or one twentieth of the total length.

[0042] Continue to see Figures 4 to 6 In the central cross-sectional direction of the connection between the grid electrode and the solar cell, the length of the second connection area is greater than the length of the first connection area. More preferably, the length of the second connection area is more than twice the length of the first connection area. For solar cells without a main grid, the welding tension is greater than 1N, and for solar cells with a main grid, the welding tension is greater than 2.5N.

[0043] Continue to see Figures 4 to 6 In the central cross-sectional direction of the connection portion between the grid line electrode and the solar cell sheet, the area of ​​the second connection region is smaller than the area of ​​the first connection region.

[0044] In the central cross-sectional direction of the connection between the grid electrode and the solar cell, when the total length of the connection is less than 1.5 mm, the length ratio of the second connection area to the first connection area is greater than 1.5, and for a solar cell without a main grid, the welding tension is greater than 0.8 N, and for a solar cell with a main grid, the welding tension is greater than 2 N.

[0045] See also Figures 4 to 6 The first connection area and the second connection area, together with the third connection area located below the solder strip, constitute the connection part, so that the lower part of the solder strip and the battery cell are firmly fixed, while the starting point of the tensile failure on both sides is far away from the main connection part (third connection area) between the solder strip and the battery cell. Within a certain length range, the longer the second connection area is, the greater the additional tensile force it contributes. However, in the functional structure design of some battery cells, the second connection area is not allowed to have enough space to extend, which will limit the tensile contribution of the second connection area.

[0046] It should be noted that the applicant has found in the research that the length of the first connection area, its edge shape, and the length and thickness of the second connection area are related to the thickness of the solder strip, the composition of the gate electrode, the amount of solder paste applied, and the process during soldering.

[0047] In the present application, the thickness of the welding strip is 0.1-0.5 mm, preferably between 0.12-0.25 mm. For example, the thickness of the welding strip is 0.1 mm, 0.12 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm or 0.5 mm.

[0048] The composition of the gate electrode is a silver electrode or a tin electrode. As understood by those skilled in the art, a silver electrode is an electrode whose main conductive component is silver, and is prepared by screen printing, laser transfer, etc. A tin electrode is an electrode whose main conductive component is tin, and is prepared by electroplating, evaporation, etc.

[0049] Before soldering, more specifically, before placing the soldering ribbon on the gate line electrode, solder paste may be coated on the gate line electrode at the position to be soldered.

[0050] During welding, laser welding, infrared welding, heating welding or welding during hot pressing can be used. Preferably, during welding, the parts to be welded are placed in a vacuum environment with a vacuum degree of -10KPa to -80KPa. The provision of the vacuum environment can refer to the prior art, CN118106614A, CN117096213A, CN219852605U, etc.

[0051] Specifically, as the thickness of the welding strip decreases, the total length of the first connection area and the second connection area becomes longer, and the length of the second connection area becomes longer.

[0052] When the gate line electrode is a tin electrode, compared with the silver electrode, the total length of the first connection region and the second connection region is longer, and the length of the second connection region is longer.

[0053] When applying solder paste, the total length of the first connection area and the second connection area is longer, and the length of the second connection area is longer.

[0054] When welding under vacuum conditions, the total length of the first connection area and the second connection area is longer, and as the vacuum degree decreases, the total length of the first connection area and the second connection area increases, and the length of the second connection area increases.

[0055] Those skilled in the art can understand that the connecting portion is the part connecting the soldering ribbon and the battery cell, which is the alloy layer formed by the soldering ribbon and the gate electrode metal (and / or the main gate electrode metal) and the metal layer of tin or other auxiliary solder during welding.

[0056] In the photovoltaic solar cell module of the present application, the connection portion between the welding strip and the grid line has a second connection area extending outward in addition to the first connection area, which increases the welding length of the welding strip and the grid line, and also increases the welding area of ​​the welding strip and the cell sheet. Thus, the tension of the welding strip is increased, which has a good improvement on the problems of cold welding and insufficient tension of the main grid solar cell photovoltaic module.

[0057] For solar cells with main grids, the photovoltaic solar cell assembly of the present application can further increase the tensile force and avoid the problem of welding stress concentration.

[0058] In one embodiment, the cell is a main grid solar cell, and the welding strip is arranged above the main grid electrode and perpendicular to the auxiliary grid electrode.

[0059] In the photovoltaic module of solar cells with main grids, the welding strips and the solar cells have connecting parts, which are similar to the thickening of the grid lines in the aforementioned photovoltaic module of solar cells without main grids. In the cross-sectional direction of the center of the auxiliary grid connected to the welding pad (for a main grid without a welding pad, it is in the cross-sectional direction of the center of the auxiliary grid connected to the main grid), the distribution of the connecting parts is the same as in the aforementioned embodiment.

[0060] In some other embodiments, in order to avoid short circuit, an insulating glue is coated on the gate line electrode, wherein the second connection region is blocked by the insulating glue in the length direction and cannot be fully expanded and formed.

[0061] Take the back contact solar cell with main grid as an example, see Figure 7 , is a schematic diagram of the structure in which the welding strip is placed on a solar cell with a main grid. In order to show the relative relationship between the auxiliary grid electrode, the main grid electrode, the welding pad, the insulating glue and the welding strip, the lower part of the figure only illustrates the main grid electrode and the auxiliary grid electrode, the middle part illustrates the insulating glue on this basis, and the upper part illustrates the welding strip on this basis. It can be seen from the figure that the welding strip 2 is placed parallel to the main grid electrode 12, and the connection position is the position of the welding pad 13, wherein part of the auxiliary grid electrode 11, the main grid electrode 12 and the outer side of the welding pad 13 are covered by the insulating glue 3. At this time, in the central cross-sectional direction of the grid line electrode (fine grid electrode) and the solar cell connection part, the connection part is distributed below and on both sides of the welding strip, and the connection part on each side includes a first connection area close to the welding strip, and a second connection area extending away from the welding strip, the first connection area and the second connection area are adjacent, wherein the length of the second connection area is greater than the length of the first connection area, and the thickness change per unit length of the second connection area is less than the thickness change per unit length of the first connection area. Those skilled in the art can understand that the expanded molding length of the second connection region is related to the position of the insulating glue. The less the insulating glue covers the fine gate electrode, the longer the expanded molding length of the second connection region.

[0062] See also Figure 8 , in accordance with Figure 7 The SEM image of the centerline cross section of the auxiliary grid welded in the same way as above shows that the third connection area is formed normally, the first connection area is formed, and the second connection area cannot be fully developed and formed due to the obstruction of the insulating glue.

[0063] It should be noted that the photovoltaic solar cell module provided by the present application includes a welded full-panel solar cell, and after the welding is completed, it also includes steps such as hot pressing packaging, or the welding is completed during the hot pressing packaging. At this time, the photovoltaic solar cell module also includes a heat sealing layer above and below the cell and a photovoltaic glass layer. The technical solution of the present application is to achieve good welding. The layout, welding method and hot pressing method of the photovoltaic solar cell module can all refer to the prior art. Other components of the photovoltaic solar cell module, such as photovoltaic glass, can also refer to the prior art.

[0064] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. A photovoltaic solar cell assembly, comprising a cell sheet and a welding ribbon, wherein: The cell has a grid electrode on one side or both sides, and the welding strip is correspondingly arranged on one side or both sides of the cell and welded to the corresponding grid electrode on the solar cell, characterized in that: The soldering ribbon and the solar cell have a connection portion, and in the extension direction of the central cross section of the connection portion between the grid line electrode and the solar cell, the connection portion is distributed below and on both sides of the soldering ribbon, and the connection portions on both sides include a first connection area close to the soldering ribbon and a second connection area away from the soldering ribbon, and the first connection area and the second connection area are adjacent to each other, wherein the length of the second connection area is greater than the length of the first connection area, and the thickness change per unit length of the second connection area is less than the thickness change per unit length of the first connection area.

2. The photovoltaic solar cell assembly according to claim 1, characterized in that: In the central cross-sectional direction of the connection portion between the grid electrode and the solar cell, the first connection area is a triangular area between the side of the welding strip and the surface of the solar cell, wherein the edge of the first connection area is close to a line, has a convex arc shape, or a concave arc shape.

3. The photovoltaic solar cell assembly according to claim 1, characterized in that: In the central cross-sectional direction of the connection portion between the grid line electrode and the solar cell, the length of the second connection region is more than twice the length of the first connection region.

4. The photovoltaic solar cell assembly according to claim 1, characterized in that: In the central cross-sectional direction of the grid line electrode and the solar cell connecting portion, the area of ​​the second connecting region is smaller than the area of ​​the first connecting region.

5. The photovoltaic solar cell assembly according to claim 1, characterized in that: In the central cross-sectional direction of the connection portion between the grid line electrode and the solar cell sheet, when the total length of the connection portion is less than 1.5 mm, the length ratio of the second connection region to the first connection region is greater than 1.

5.

6. The photovoltaic solar cell assembly according to claim 1, characterized in that: The gate line electrode is thickened at the connection position where it contacts the welding strip, and the thickened position is the thickened portion. The length of the thickened portion is greater than the width of the welding strip. In the central cross-sectional direction of the connection portion between the gate line electrode and the solar cell sheet, the end of the second connection area is close to the edge of the thickened portion, located at the edge of the thickened portion or beyond the edge of the thickened portion.

7. The photovoltaic solar cell assembly according to claim 1, characterized in that: The thickness of the welding strip is 0.1 to 0.5 mm.

8. The photovoltaic solar cell assembly according to claim 1, characterized in that: The gate line electrode is a silver electrode or a tin electrode.

9. The photovoltaic solar cell assembly according to claim 1, characterized in that: Before placing the soldering ribbon on the gate line electrode, solder paste is applied to the connection position between the gate line electrode and the soldering ribbon.

10. The photovoltaic solar cell assembly according to claim 1, characterized in that: During welding, the solar cell sheet and the welding ribbon are placed in a vacuum environment with a vacuum degree of -10KPa to -80KPa.

11. The photovoltaic solar cell assembly according to claim 1, characterized in that: The cell is a main grid-free solar cell, and the welding strip is arranged perpendicular to the fine grid electrode.

12. The photovoltaic solar cell assembly according to claim 1, characterized in that: The cell is a solar cell with a main grid, and the welding strip is arranged in parallel above the main grid electrode and vertically to the fine grid electrode.

13. The photovoltaic solar cell assembly according to any one of claims 1 to 12, characterized in that: Insulating glue is arranged on the surface of the solar cell, and the welding strip and the solar cell sheet have a connecting portion. In the central cross-sectional direction of the connecting portion between the grid electrode and the solar cell sheet, the connecting portion is distributed below and on both sides of the welding strip, and the connecting portion on each side includes a first connecting area close to the welding strip, and a second connecting area extending away from the welding strip, and the first connecting area and the second connecting area are adjacent to each other, wherein the length of the second connecting area is greater than the length of the first connecting area, and the thickness variation per unit length of the second connecting area is less than the thickness variation per unit length of the first connecting area; the second connecting area is blocked by the insulating glue in the length direction and the periphery fails to be fully unfolded and formed.

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