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] This application belongs to the field of solar cell processing technology and relates to a photovoltaic solar cell module. Background Technology

[0002] In photovoltaic solar cell modules, the solar cells are connected to the grid electrodes via solder ribbons. Currently, incomplete soldering and insufficient solder pull are pressing technical problems that need to be solved. At the same time, the rework of defective components wastes production time and increases production costs. Utility Model Content

[0003] In order to solve the problems existing in the prior art, this utility model provides a photovoltaic solar cell module.

[0004] A photovoltaic solar cell module includes solar cells and solder ribbons. The solar cells have grid electrodes on one or both sides, and the solder ribbons are correspondingly disposed on one or both sides of the solar cells and soldered to the corresponding grid electrodes on the solar cells.

[0005] The welded strip and the solar cell have a connection portion. In the extension direction of the central cross-section of the connection portion between the grid electrode and the solar cell, the connection portion is distributed below and on both sides of the weld strip. The connection portion on both sides includes a first connection area close to the weld strip and a second connection area away from the weld strip. The first connection area and the second connection area are adjacent to each other. The length of the second connection area is greater than the length of the first connection area, and the thickness variation per unit length of the second connection area is less than the thickness variation per unit length of the first connection area.

[0006] In one embodiment of a photovoltaic solar cell module, in the central cross-sectional direction of the connection between the grid electrode and the solar cell, the first connection area is a triangular-like area between the side of the solder strip and the surface of the cell, wherein the edge of the first connection area is nearly linear and has an outwardly convex arc shape or an inwardly concave arc shape.

[0007] In one embodiment of the photovoltaic solar cell module, in the direction of the central cross-section of the connection between the grid electrode and the solar cell, the length of the second connection region is more than twice the length of the first connection region.

[0008] In one embodiment of the photovoltaic solar cell module, the area of ​​the second connection region is smaller than the area of ​​the first connection region in the central cross-sectional direction of the connection between the grid electrode and the solar cell.

[0009] In one embodiment of the photovoltaic solar cell module, when the total length of the connection portion in the central cross-sectional direction of the connection portion between the grid electrode and the solar cell 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 one embodiment of the photovoltaic solar cell module, the grid line electrode is thickened at the connection position where it contacts the solder strip. The thickened position is called the thickened part. The length of the thickened part is greater than the width of the solder strip. In the central cross-sectional direction of the connection between the grid line electrode and the solar cell, the end of the second connection area is close to the edge of the thickened part, located at or beyond the edge of the thickened part.

[0011] In one embodiment of the photovoltaic solar cell module, the solder strip thickness is 0.1 to 0.5 mm.

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

[0013] In one embodiment of the photovoltaic solar cell module, solder paste is pre-applied at the connection points between the grid electrodes and the solder ribbon.

[0014] In one embodiment of the photovoltaic solar cell module, the connection part is formed in a vacuum environment with a vacuum level of -10 kPa to -80 kPa.

[0015] One embodiment of a photovoltaic solar cell module, wherein the cell is a gridless solar cell, and the solder ribbon is arranged perpendicular to the fine grid electrode.

[0016] One embodiment of a photovoltaic solar cell module, wherein the cell is a grid-connected solar cell, and the solder strip is arranged parallel above the grid electrode and perpendicular to the fine grid electrode.

[0017] In one embodiment of a photovoltaic solar cell module, an insulating adhesive is provided on the surface of the solar cell. The solder 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 solder strip. Each side of the connecting portion includes a first connecting area close to the solder strip and a second connecting area extending away from the solder strip. The first connecting area and the second connecting area are adjacent to each other. 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 outer periphery of the second connecting area is blocked by the insulating adhesive in the length direction and cannot be fully unfolded and formed.

[0018] This application achieves the following technical effects through the above technical solution.

[0019] The photovoltaic solar cell module of this application, after welding, has a specific connection between the solder strip and the cell, which has greater welding pull and better welding effect. In particular, it has a good welding effect for the gridless solar cell module of this embodiment, and solves the problems of poor welding and low welding pull of gridless solar cell modules in the prior art. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of two adjacent cells and the solder strip connecting them in a photovoltaic solar cell module according to one 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, in which the electrode grid lines have thickened portions;

[0024] Figures 4 to 6 for Figure 2 SEM image of the central cross-section of the grid electrode and the connector;

[0025] Figure 7 This is a schematic diagram of a photovoltaic solar cell module in which solder ribbons are placed on a solar cell with a main grid, according to one embodiment.

[0026] Figure 8 for Figure 7 SEM image of the central cross-section of the grid electrode and the connector;

[0027] In the figure, solar cell 1, solder ribbon 2, insulating adhesive 3, grid line electrode 11, main grid electrode 12, thickened part 111, and solder pad 13. Detailed Implementation

[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0030] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0031] A photovoltaic solar cell module includes a cell and a solder ribbon, wherein the cell has grid electrodes on one or both sides, and the solder ribbon is disposed on one or both sides of the cell and soldered to the corresponding grid electrodes on the solar cell.

[0032] In one embodiment, the solar cell is a gridless solar cell, with the solder ribbon and the grid line electrodes soldered thereto arranged vertically. See also Figure 1 and Figure 2 Taking a back-contact solar cell as an example, the grid electrodes are located on the back of the cell. Figure 1 This refers to two adjacent solar cells 1 and the solder strip 2 connecting them in a photovoltaic solar cell module. Figure 1 The diagram schematically shows the solar cells and solder ribbons, but does not show details of the solder ribbons and grid electrodes, such as the insulating adhesive placed at the corresponding positions of the grid electrodes to avoid short circuits. Figure 1 The circular area in the diagram represents the location of the solder strip and the area near the welded area of ​​a grid line electrode. Figure 2 for Figure 1 Enlarged view of the circular schematic area. Figures 4 to 6 This is a SEM image of the central cross-section of the grid electrode and the connector.

[0033] The photovoltaic solar cell module of this application, after welding, has a specific connection between the solder strip and the cell, which has greater welding pull and better welding effect. In particular, it has a good welding effect for the gridless solar cell module of this embodiment, and solves the problems of poor welding and low welding pull of gridless solar cell modules in the prior art.

[0034] Specifically, the photovoltaic solar cell module of this application has a connection portion between the soldered ribbon and the solar cell. 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 solder ribbon. The connection portions on both sides include a first connection area close to the solder ribbon and a second connection area extending away from the solder ribbon. The first and second connection areas are adjacent, wherein the length of the second connection area is greater than the length of the first connection area, and the thickness variation per unit length of the second connection area is less than the thickness variation per unit length of the first connection area.

[0035] Without a second connection area, the tensile failure point at the weld joint between the solder ribbon and the battery cell is located at the intersection of the first connection area and the battery cell. The tensile failure quickly propagates to the third connection area located below the solder ribbon, tearing part of the third connection area until it is completely torn, causing the solder ribbon and battery cell to fail or detach completely. In this embodiment, a second connection area extending away from the solder ribbon is provided in addition to the first connection area near the solder ribbon. The tensile failure point at the weld joint between the solder ribbon and the battery cell is located at the end of the contact area between the second connection area and the battery cell. The tensile failure point needs to travel a long distance to propagate to the intersection of the first connection area and the battery cell. Only when the welded battery cell is subjected to greater tensile force will it affect the third connection area located below the solder ribbon, causing partial tearing or detachment of the third connection area. The second connection area effectively increases the tensile strength of the welded battery cell; specific comparative data can be found in the detailed embodiments below.

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

[0037] It should be noted that the first connection area and the second connection area being adjacent means that the first connection area and the second connection area are connected, not disconnected.

[0038] In some embodiments, the gate electrode is thickened at the connection point where it contacts the solder strip; for ease of description, this is defined as the thickened portion. The length of the thickened portion is greater than the width of the solder strip. See [link to documentation]. Figure 3 This is an enlarged view of the weld strip and the welded area of ​​the grid line with the thickened portion, and the vicinity thereof. In this type of embodiment, the end of the second connection region is close to the edge of the thickened portion, located at or beyond the edge of the thickened portion.

[0039] See Figures 4 to 6 , Figures 4 to 6 This is a SEM image of the central cross-section of the gate electrode and the connector. Wherein, Figure 5 for Figure 4 Enlarged image on the left, Figure 6 for Figure 4 Enlarged view on the right. The first connection area is a triangular-like area between the side of the solder strip and the surface of the battery cell. Its connecting side (right-angled side) is connected to both the side of the solder strip and the surface of the battery cell. The edge (hypotenuse) of the first connection area is nearly linear. In some other embodiments, the edge of the first connection area has an outwardly convex arc shape or an inwardly concave arc shape.

[0040] The second connecting region is an elongated strip extending along its length. The thickness per unit length within the second connecting region varies little, but its thickness abruptly decreases compared to the first connecting region. Figure 4 In the image, the adjacent positions of the first and second connection areas are shown by yellow circles.

[0041] The thickness variation per unit length of the second connecting region is less than that of the first connecting region. In other words, the edge of the first connecting region has a steeper shape, while the edge of the second connecting region has a gentler shape. It should be noted that the thickness variation per unit length is not necessarily in units of one millimeter or one micrometer; it can be one-tenth or one-twentieth of the total length, etc.

[0042] See also 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 region is greater than the length of the first connection region. More preferably, the length of the second connection region is more than twice the length of the first connection region. For gridless solar cells, the welding pull force is greater than 1N; for solar cells with grids, the welding pull force is greater than 2.5N.

[0043] See also Figures 4 to 6 In the direction of the central cross-section of the connection between the grid electrode and the solar cell, 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. For a gridless solar cell, the welding pull force is greater than 0.8 N, and for a grid-connected solar cell, the welding pull force is greater than 2 N.

[0045] See Figures 4 to 6 The first and second connection areas, together with the third connection area located below the solder strip, constitute the connection portion. This securely fixes the lower part of the solder strip to the battery cell while ensuring that the tensile failure initiation point on both sides is far away from the main connection portion (third connection area) between the solder strip and the battery cell. Within a certain length range, the longer the second connection area, the greater the additional tensile force it contributes. However, in some battery cell functional structure designs, sufficient space is not allowed for the second connection area to extend outward, which limits its tensile force contribution.

[0046] It should be noted that the applicant found in the study 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 solder strip thickness, the gate electrode composition, the amount of solder paste applied, and the soldering process.

[0047] In this application, the thickness of the solder strip is 0.1 to 0.5 mm, preferably between 0.12 and 0.25 mm. For example, the thickness of the solder 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 grid electrodes are composed of silver or tin electrodes. As understood by those skilled in the art, silver electrodes are electrodes whose main conductive component is silver, and are prepared using processes such as screen printing or laser transfer. Tin electrodes are electrodes whose main conductive component is tin, and are prepared through methods such as electroplating or vapor deposition.

[0049] Before soldering, more specifically, before placing the solder ribbon onto the gate electrode, solder paste can be applied to the area of ​​the gate electrode to be soldered.

[0050] Welding can be performed using methods such as laser welding, infrared welding, heating welding, or hot pressing. Preferably, the parts to be welded are placed in a vacuum environment with a vacuum level of -10 kPa to -80 kPa. The provision of the vacuum environment can be referenced from existing technologies such as CN118106614A, CN117096213A, and CN219852605U.

[0051] Specifically, as the thickness of the solder 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 also becomes longer.

[0052] When the gate electrode is a tin electrode, compared to a 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 also longer.

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

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

[0055] As will be understood by those skilled in the art, the connection portion is the part that connects the solder strip and the battery cell, and is an alloy layer formed by the solder strip and the grid electrode metal (and / or the main grid electrode metal) and a metal layer of tin or other auxiliary solder during the soldering process.

[0056] The photovoltaic solar cell module of this application has a second connection area extending outward from the first connection area at the connection between the solder ribbon and the grid line. This increases the welding length of the solder ribbon and the grid line, and also increases the welding area between the solder ribbon and the solar cell. This increases the tensile strength of the solder ribbon, effectively improving the problems of poor soldering and insufficient tensile strength in gridless solar cell photovoltaic modules.

[0057] For solar cells with main grids, the photovoltaic solar cell module of this application can further improve tensile strength and avoid welding stress concentration problems.

[0058] In one embodiment, the solar cell is a solar cell with a main grid, and the solder strip is disposed above the main grid electrode and perpendicular to the sub-grid electrode.

[0059] In photovoltaic modules with solar cells having a main grid, the solder ribbon and solar cell have a connection portion, similar to the aforementioned photovoltaic modules without a main grid, where the grid lines are thickened. In the cross-sectional direction of the sub-grid center connected to the solder pad (for a main grid without a solder pad, in the cross-sectional direction of the sub-grid center connected to the main grid), the distribution of the connection portion is the same as in the aforementioned embodiments.

[0060] In some other embodiments, to avoid short circuits, insulating adhesive is applied to the grid line electrodes, wherein the periphery of the second connection area is blocked by the insulating adhesive in the length direction and cannot be fully unfolded.

[0061] Taking a back-contact solar cell with a main grid as an example, see Figure 7 This is a schematic diagram of a solar cell with solder ribbon placed on a main grid. To illustrate the relative relationships of the sub-grid electrode, main grid electrode, pad, insulating adhesive, and solder ribbon, the lower part of the diagram only shows the main grid electrode and sub-grid electrode, the middle part shows the insulating adhesive, and the upper part shows the solder ribbon. As can be seen, the solder ribbon 2 is placed parallel above the main grid electrode 12, connecting at the pad 13. Parts of the sub-grid electrode 11, main grid electrode 12, and pad 13 are covered by insulating adhesive 3. At this point, in the central cross-sectional direction of the connection between the grid line electrode (fine grid electrode) and the solar cell, the connection portion is distributed below and on both sides of the solder ribbon. Each side of the connection portion includes a first connection area close to the solder ribbon and a second connection area extending away from the solder ribbon. The first and second connection areas are adjacent, with the length of the second connection area being greater than the length of the first connection area, and the thickness variation per unit length of the second connection area being less than the thickness variation per unit length of the first connection area. As will be understood by those skilled in the art, the unfolded length of the second connection region is related to the position of the insulating adhesive; the less the insulating adhesive covers the fine grid electrode, the longer the unfolded length of the second connection region.

[0062] See Figure 8 In order to follow Figure 7 The image shows a SEM image of the cross-section along the centerline of the sub-gate welded in this manner. It can be seen that the third connection region forms normally, the first connection region forms, but the second connection region fails to fully expand and form due to the obstruction of the insulating adhesive.

[0063] It should be noted that the photovoltaic solar cell module provided in this application includes a welded sheet of solar cells. After welding, it further includes steps such as hot-press encapsulation, or welding is completed during hot-press encapsulation. In this case, the photovoltaic solar cell module also includes heat-sealing layers and photovoltaic glass layers above and below the cells. The technical solution of this application aims 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 description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A photovoltaic solar cell module, comprising solar cells and solder strips, wherein, The solar cell has grid electrodes on one or both sides, and solder ribbons are correspondingly disposed on one or both sides of the solar cell and soldered to the corresponding grid electrodes on the solar cell, characterized in that: The solder strip and the solar cell have a connection portion. In the direction of extension of the central cross-section of the connection portion between the grid electrode and the solar cell, the connection portion is distributed below and on both sides of the solder strip. The connection portion on both sides includes a first connection area close to the solder strip and a second connection area away from the solder strip. The first connection area and the second connection area are adjacent to each other. The length of the second connection area is greater than the length of the first connection area, and the thickness variation per unit length of the second connection area is less than the thickness variation per unit length of the first connection area.

2. The photovoltaic solar cell module according to claim 1, characterized in that: In the central cross-sectional direction of the connection between the grid electrode and the solar cell, the first connection area is a triangular-like area between the side of the solder strip and the surface of the cell, wherein the edge of the first connection area is nearly linear, has an outwardly convex arc shape, or an inwardly concave arc shape.

3. The photovoltaic solar cell module according to claim 1, characterized in that: In the central cross-sectional direction of the connection between the grid 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 module according to claim 1, characterized in that: In the central cross-sectional direction of the connection between the grid electrode and the solar cell, the area of ​​the second connection region is smaller than the area of ​​the first connection region.

5. The photovoltaic solar cell module according to claim 1, characterized in that: In the direction of the central cross-section 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.

6. The photovoltaic solar cell module according to claim 1, characterized in that: The grid electrode is thickened at the connection point where it contacts the solder strip. The thickened part is called the thickened part. The length of the thickened part is greater than the width of the solder strip. In the central cross-sectional direction of the connection between the grid electrode and the solar cell, the end of the second connection area is close to the edge of the thickened part, located at or beyond the edge of the thickened part.

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

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

9. The photovoltaic solar cell module according to claim 1, characterized in that: Solder paste is pre-applied at the connection points between the gate electrode and the solder strip.

10. The photovoltaic solar cell module according to claim 1, characterized in that: The connection is formed in a vacuum environment with a vacuum level of -10 kPa to -80 kPa.

11. The photovoltaic solar cell module according to claim 1, characterized in that: The battery is a gridless solar cell, and the solder strip is arranged perpendicular to the fine grid electrode.

12. The photovoltaic solar cell module according to claim 1, characterized in that: The battery is a solar cell with a main grid, and the solder ribbon is arranged parallel above the main grid electrode and perpendicular to the fine grid electrode.

13. The photovoltaic solar cell module according to any one of claims 1 to 12, characterized in that: An insulating adhesive is applied to the surface of the solar cell. The solder 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 solder strip. Each side of the connecting portion includes a first connecting area close to the solder strip and a second connecting area extending away from the solder strip. The first and second connecting areas are adjacent to each other. 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 outer periphery of the second connecting area is blocked by the insulating adhesive in the length direction and cannot be fully unfolded and formed.

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