Negative spacing unit of solar cell

Abstract

The utility model relates to series connection of photovoltaic cells, in particular to a negative spacing unit of a solar cell, which is used for solving the technical problems that in the manufacturing process of a series solar cell module in the prior art, conductive materials between adjacent cell units generally need to be welded to realize electric connection, and the manufacturing cost is low. The welding mode has the technical problems that the welding process is complex and low in efficiency, the welding temperature can generate adverse effects on the batteries, and the reliability and the stability of the welding process are insufficient, and the conventional series welding process cannot process the batteries with inconsistent welding strip numbers, and the batteries in an overlapping area in a lamination process are relatively large in stress after being laminated, so that the welding efficiency is relatively high. And hidden cracks are easy to generate, so that the battery fails. As a series unit, the solar cell negative spacing unit can realize rapid manufacturing of a series cell assembly.

Description

Technical Field

[0001] The utility model relates to the series connection of photovoltaic cells, in particular to a solar cell negative spacing unit. Background Art

[0002] In the photovoltaic module manufacturing process, connecting cells in series is a critical step in achieving the module's power generation function. Conventional string soldering primarily uses solder ribbons to connect the cells, creating a current path. Traditional string soldering typically wraps the ribbons around the other side of the cell, ensuring the same number of ribbons on both sides. This design works well for cells with a consistent number of ribbons, but fails to achieve effective series connection when the number of ribbons is inconsistent.

[0003] With the development of photovoltaic technology and the diversification of its application scenarios, the requirements for series connection of solar cells are becoming increasingly stringent. To meet these new demands, the lamination process has been introduced into the manufacturing of photovoltaic modules. By overlapping the edges of different solar cells, it is possible to connect solar cells with inconsistent numbers of solder ribbons in series without changing the shape and size of the cells. This innovative process solves the problem of inconsistent solder ribbon numbers to a certain extent and can also improve the power density and material utilization of the modules.

[0004] However, because the edges of the cells are overlapped and connected, especially during the lamination process, the overlapping areas are often subjected to greater mechanical stress. Excessive stress concentration during the lamination process can cause hidden cracks in the cells, which not only reduces the mechanical strength of the cells but can also further degrade their electrical performance, ultimately affecting the overall reliability and service life of the PV module.

[0005] Furthermore, existing techniques for manufacturing series-connected solar cell modules typically require welding the conductive material between adjacent cells to achieve electrical connections. This welding method has the following drawbacks: the welding process is complex and inefficient, the welding temperature can adversely affect the cells, and the reliability and stability of the welding process are insufficient. Utility Model Content

[0006] The purpose of the utility model is to solve the problems in the prior art that, in the process of manufacturing series-connected solar cell modules, it is usually necessary to weld the conductive materials between adjacent battery cells to achieve electrical connection. This welding method has the following technical problems: the welding process is complicated and inefficient, the welding temperature has an adverse effect on the battery, and the reliability and stability of the welding process are insufficient. In addition, the conventional string welding process cannot handle batteries with inconsistent numbers of welding ribbons, and the batteries in the overlapping areas of the stacking process are subjected to greater stress after lamination, which is prone to hidden cracks and causes battery failure. A solar cell negative spacing unit is provided.

[0007] In order to solve the deficiencies of the above-mentioned prior art, the present invention provides the following technical solutions:

[0008] A solar cell negative spacing unit includes a cell substrate; the special features of the unit are:

[0009] The light-receiving surface of the battery substrate is provided with a plurality of light-receiving surface welding strips arranged in parallel and at equal intervals, and the back-lighting surface is provided with a plurality of back-lighting surface welding strips arranged in parallel and at equal intervals. The same end of all the light-receiving surface welding strips of the battery substrate extends a mm from the edge of the battery substrate and is connected to a conductive strip perpendicular to the extension direction of the light-receiving surface welding strip. The conductive strip and the battery substrate are respectively located on both sides of all the light-receiving surface welding strips. The other ends of all the light-receiving surface welding strips and both ends of all the back-lighting surface welding strips do not protrude from the edge of the battery substrate. The spacing d1 between adjacent light-receiving surface welding strips is greater than or equal to the spacing d2 between adjacent back-lighting surface welding strips. The value of a is 1 to 5 mm, and the values of d1 and d2 are 0.5 to 3 mm.

[0010] A light-receiving overlapping area is provided on the light-receiving surface of the cell substrate on the side close to the conductive strip, a backlight overlapping area is provided on the backlight surface away from the conductive strip, and a backlight non-overlapping area is provided on the side close to the conductive strip. The backlight overlapping area is used to stack with the conductive strip and light-receiving overlapping area of another cell substrate;

[0011] All backlight surface welding strips in the backlight non-overlapping area are covered with adhesive film, and part of the adhesive film extends out of the edge of the battery substrate, covering and connecting all light-receiving surface welding strips and conductive strip connections on the battery substrate.

[0012] Furthermore, the light receiving overlapping area is provided with elastic material for buffering.

[0013] Furthermore, the conductive strip is a column with a coating on its surface, and its length is greater than or equal to the length of the battery substrate in the same direction;

[0014] The cross section of the conductive strip is a circle with a diameter of 0.1 to 0.5 mm, or a rectangle with a width of 1.5 to 3 mm and a thickness of 0.1 to 0.2 mm.

[0015] Furthermore, the conductive strip is a cylinder, composed of multiple thin cylinders with a diameter of 0.05 to 0.1 mm connected to each other by outer walls, and a coating is provided on the surface of each thin cylinder; or, the conductive strip is a strip, composed of multiple thin cylinders with a diameter of 0.05 to 0.1 mm connected in sequence by outer walls, and a coating is provided on the surface of each thin cylinder.

[0016] Furthermore, the coating of the conductive strip is a low-temperature alloy or a conductive resin;

[0017] The low-temperature alloy contains at least two of tin, lead, silver, bismuth, indium, zinc, and cerium, and has a thickness of 1 to 30 μm.

[0018] Furthermore, the light-facing surface solder strip and the back-facing surface solder strip are both cylinders provided with a coating, the radial cross-sectional diameter D1 of the light-facing surface solder strip is less than or equal to the radial cross-sectional diameter D2 of the back-facing surface solder strip, the values of D1 and D2 are 0.05 to 0.15 mm, and the coating of the light-facing surface solder strip and the back-facing surface solder strip is an alloy or a conductive resin.

[0019] Furthermore, the elastic material is one of POE, UV glue, and silicone rubber, with a thickness of 0.2 to 3 mm and a Shore hardness of 15 to 40.

[0020] Furthermore, the elastic material corresponds to the shape and position of all the light-receiving surface welding strips in the light-receiving overlapping area, or has a rectangular shape with a length consistent with the length of the battery substrate in the same direction and a width of 0.2 to 2 mm.

[0021] Furthermore, the adhesive film is one of POE, EPE, and PVB.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) The utility model provides a solar cell negative spacing unit, which, as a series connection unit, can realize the rapid production of series cell modules. When connected in series, multiple solar cell negative spacing units are stacked and arranged in sequence. After lamination, the production of series cell modules can be completed, eliminating the complicated welding process, greatly improving production efficiency, and avoiding the influence of temperature on the cell and the welding strip when the conductive strip is welded on the cell surface, thereby maintaining the stability of cell performance, extending the service life of the series cell module, and reducing the requirements for equipment and operator skills, thereby improving the controllability and yield of the production process, and being suitable for large-scale production applications.

[0024] (2) The utility model provides a solar cell negative spacing unit that simplifies the process of connecting the cell modules in series. At the same time, elastic material is provided in the light-receiving overlapping area of the cell substrate. The elastic material can be softened during lamination to protect the cell edge from being crushed by the welding ribbon.

[0025] (3) In a solar cell negative spacing unit of the present invention, an adhesive film is used to strengthen the connection between the conductive strip and the cell substrate, so as to prevent the conductive strip from being too heavy during transportation, causing the light-receiving surface welding strip to bend and deform. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural schematic diagram of an embodiment of a solar cell negative spacing unit of the present utility model;

[0027] Figure 2This is a schematic structural diagram of an embodiment of the present invention when multiple stacks are connected in series, with the light-receiving surface facing downward;

[0028] Figure 3 This is a structural schematic diagram of an embodiment of the present invention when multiple embodiments are stacked in series, with the light-receiving surface facing upward.

[0029] The following are the descriptions of the reference numerals:

[0030] 1-battery substrate; 21-light-receiving surface solder strip; 22-backlight surface solder strip; 31-light-receiving overlapping area, 32-backlight overlapping area, 33-backlight non-overlapping area; 4-conductive strip; 5-adhesive film; 6-elastic material. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0032] Reference Figures 1 to 3 , a solar cell negative spacing unit, including a cell substrate 1.

[0033] The light-receiving surface of the battery substrate 1 is provided with multiple parallel and evenly spaced light-receiving surface welding strips 21, and the backlight surface is provided with multiple parallel and evenly spaced backlight surface welding strips 22. The light-receiving surface welding strips 21 and the backlight surface welding strips 22 are both arranged perpendicular to the long side of the battery substrate 1.

[0034] The same end of all the light-receiving surface welding strips 21 of the battery substrate 1 extends out amm from the edge of the battery substrate 1, and is welded with a conductive strip 4 perpendicular to the extension direction of the light-receiving surface welding strip 21. The conductive strip 4 and the battery substrate 1 are respectively located on both sides of all the light-receiving surface welding strips 21. The other end of all the light-receiving surface welding strips 21 and the two ends of all the back-lighting surface welding strips 22 are flush with the edge of the battery substrate 1; the spacing d1 between adjacent light-receiving surface welding strips 21 is greater than or equal to the spacing d2 between adjacent back-lighting surface welding strips 22.

[0035] The light-facing surface welding strip 21 and the back-facing surface welding strip 22 are both cylindrical bodies provided with a coating. The radial cross-sectional diameter D1 of the light-facing surface welding strip 21 is smaller than or equal to the radial cross-sectional diameter D2 of the back-facing surface welding strip 22 .

[0036] In this embodiment, a = 2 mm, d1 = 2 mm, d2 = 1 mm, and D1 = D2 = 0.1 mm. The coatings of the light-receiving surface solder strips 21 and the back-lighting surface solder strips 22 are alloys, specifically tin-lead alloys. The spacing d1 between adjacent light-receiving surface solder strips 21 is greater than the spacing d2 between adjacent back-lighting surface solder strips 22. This can reduce the light-shielding area of the light-receiving surface solder strips 21 and increase the battery's power generation. In other embodiments, the radial cross-sectional diameter D1 of the light-receiving surface solder strips 21 is smaller than the radial cross-sectional diameter D2 of the back-lighting surface solder strips 22. This can also reduce the light-shielding area of the light-receiving surface and increase the battery's power generation. However, this requires reducing the spacing between the solder strips on the back-lighting surface to reduce the overall solder strip series resistance, increase the battery's fill factor, and improve battery efficiency.

[0037] In other embodiments, the value of a can be 1-5 mm, the values of d1 and d2 can be 0.5-3 mm, the values of D1 and D2 can be 0.05-0.15 mm, and the coating of the light-receiving surface welding strip 21 and the backlight surface welding strip 22 can be an alloy or a conductive resin.

[0038] The conductive strip 4 is a column with a coating, and its length is greater than the long side of the battery substrate 1; the cross section of the conductive strip 4 is a rectangle with a width of 2 mm and a thickness of 0.1 mm, and the coating is a tin-lead-bismuth alloy with a thickness of 15 μm.

[0039] In other embodiments, the cross-section of the conductive strip 4 can be a circle with a diameter of 0.1 to 0.5 mm, or a rectangle with a width of 1.5 to 3 mm and a thickness of 0.1 to 0.2 mm; when the cross-section of the conductive strip 4 is rectangular, in order to simultaneously ensure good contact between the conductive strip 4 and the backlight solder strip 22 of the adjacent battery substrate 1 and protect the battery from being crushed, the rectangle needs to have a larger aspect ratio, but an excessively large aspect ratio will increase the difficulty of making the conductive strip 4. For a rectangle with a width of more than 1.5 mm, when its thickness is less than 0.1 mm, the production cost will increase significantly. Therefore, on the premise of ensuring that the requirements of component series connection are met, a rectangle with a width of 1.5 to 3 mm and a thickness of 0.1 to 0.2 mm is selected.

[0040] In other embodiments, the conductive strip 4 is a cylinder, composed of multiple thin cylinders with a diameter of 0.05 to 0.1 mm connected to each other by outer walls, and a coating is provided on the surface of each thin cylinder; or, the conductive strip 4 is a strip, composed of multiple thin cylinders with a diameter of 0.05 to 0.1 mm connected in sequence by outer walls, and a coating is provided on the surface of each thin cylinder. The strip is softer than the conductive strip 4 composed of a single thick round welding strip, and can avoid pressing on the battery surface to cause hidden cracks.

[0041] In other embodiments, the conductive strip 4 is coated with a low-temperature alloy or conductive resin; the low-temperature alloy comprises at least two of tin, lead, silver, bismuth, indium, zinc, and cerium, and has a thickness of 1 to 30 μm. The coating is as thick as possible without significantly increasing the cost of the conductive strip 4, allowing it to melt during lamination and weld to the light-facing soldering strip 21 of the cell substrate 1 on which it resides and the back-facing soldering strip 22 of the adjacent cell substrate 1. Reliable electrical connection between the conductive strip 4 and the light-facing and back-facing soldering strips 21, 22 is achieved by increasing the contact area and coating thickness.

[0042] A light-receiving overlapping area 31 with a width w is provided on the light-receiving surface of the battery substrate 1 on the side away from the conductive strip 4, and the value of w is 1 mm; a backlight overlapping area 32 is provided on the backlight surface of the battery substrate 1 on the side away from the conductive strip 4, and a backlight non-overlapping area 33 is provided on the side close to the conductive strip 4. The backlight overlapping area 32 is used to stack with the conductive strip 4 and the light-receiving overlapping area 31 of another battery substrate 1.

[0043] The light-receiving overlap region 31 of the cell substrate 1 is provided with an elastic material 6 for cushioning. This elastic material 6 is UV adhesive, 0.5 mm thick, and has a Shore hardness of 20. It is rectangular in shape, with a length that matches the length of the cell substrate 1 in the same direction and a width of 0.5 mm. In other embodiments, the elastic material 6 can be made of one of POE (Polyolefin Elastomer), UV adhesive, or silicone, with a thickness of 0.2-3 mm and a Shore hardness of 15-40. It can correspond in shape and position to all light-receiving surface solder strips 21 in the light-receiving overlap region 31, or it can be rectangular in shape, with a length that matches the length of the cell substrate 1 in the same direction and a width of 0.2-2 mm. The elastic material 6 can simply serve as a cushion and does not need to be conductive. It softens during lamination, protecting the cell edges from being crushed by the solder strips. It also secures the solder strips extending from the light-receiving surface, preventing them from protruding from the cell edge and potentially causing them to shift and fall off.

[0044] All backlight-side solder strips 22 in the backlight non-overlapping area 33 are covered with an adhesive film 5. Portions of the adhesive film 5 extend over the edge of the cell substrate 1, covering and connecting all locations where the light-receiving solder strips 21 on the cell substrate 1 are welded to the conductive strips 4. The adhesive film 5 strengthens the connection between the conductive strips 4 and the cell substrate 1, preventing the light-receiving solder strips 21 from bending or deforming due to the weight of the conductive strips 4 during transport. The adhesive film 5 is made of POE. In other embodiments, the adhesive film 5 can be made of one of POE, EPE (Expanded Polyethylene), or PVB (Polyvinyl Butyral).

[0045] When multiple solar cell negative spacing units are connected in series, photovoltaic glass and front adhesive film 5 can be laid in order from bottom to top, and then multiple solar cell negative spacing units can be stacked and arranged in order with the light-receiving surface facing downwards, such as Figure 2 As shown, the conductive strips 4 and the light-receiving overlapping area 31 of the next solar cell negative spacing unit are overlapped on the backlight overlapping area 32 of the previous solar cell negative spacing unit; then, after welding the busbars and electrode lead wires, the backside adhesive film 5 and the backsheet or photovoltaic glass are laid on all the solar cell negative spacing units from bottom to top to complete the series connection;

[0046] In other embodiments, photovoltaic glass and back film 5 may be laid sequentially from bottom to top, and then multiple solar cell negative spacing units may be stacked and arranged in sequence with the light-receiving surfaces facing upwards, such as Figure 3 As shown, the backlight overlapping area 32 of the next solar cell negative spacing unit is overlapped on the conductive strip 4 and the light-receiving overlapping area 31 of the previous solar cell negative spacing unit; then after welding the busbars and electrode lead wires, the front adhesive film 5 and photovoltaic glass are laid on all the solar cell negative spacing units from bottom to top to complete the series connection.

[0047] It should be noted that stacking multiple solar cell negative spacing units with the light-receiving surface facing downward is suitable for single-glass modules and double-glass modules, while stacking multiple solar cell negative spacing units with the light-receiving surface facing upward is suitable for double-glass modules. The reason is that the backsheet is relatively soft and the backsheet cannot be laid first.

Claims

1. A solar cell negative spacing unit, comprising a cell substrate (1); characterized in that: The light-receiving surface of the battery substrate (1) is provided with a plurality of light-receiving surface welding strips (21) arranged in parallel and at equal intervals, and the back-lighting surface is provided with a plurality of back-lighting surface welding strips (22) arranged in parallel and at equal intervals, the same end of all the light-receiving surface welding strips (21) of the battery substrate (1) extends out from the edge of the battery substrate (1) by a mm, and is connected to a conductive strip (4) perpendicular to the extension direction of the light-receiving surface welding strip (21), the conductive strip (4) and the battery substrate (1) are respectively located on both sides of all the light-receiving surface welding strips (21), and the other ends of all the light-receiving surface welding strips (21) and the two ends of all the back-lighting surface welding strips (22) do not protrude from the edge of the battery substrate (1); the spacing d1 between adjacent light-receiving surface welding strips (21) is greater than or equal to the spacing d2 between adjacent back-lighting surface welding strips (22); the value of a is 1 to 5 mm, and the values of d1 and d2 are 0.5 to 3 mm; A light-receiving overlapping area (31) is provided on the light-receiving surface of the battery substrate (1) on the side close to the conductive strip (4), a backlight overlapping area (32) is provided on the side of the backlight surface away from the conductive strip (4), and a backlight non-overlapping area (33) is provided on the side close to the conductive strip (4), and the backlight overlapping area (32) is used to stack with the conductive strip (4) and the light-receiving overlapping area (31) of another battery substrate (1); All backlight surface welding strips (22) in the backlight non-overlapping area (33) are covered with an adhesive film (5), and a portion of the adhesive film (5) extends beyond the edge of the battery substrate (1) to cover and connect all light-receiving surface welding strips (21) and the conductive strips (4) on the battery substrate (1).

2. The solar cell negative spacing unit according to claim 1, characterized in that: The light receiving overlapping area (31) is provided with elastic material (6) for buffering.

3. The solar cell negative spacing unit according to claim 1, characterized in that: The conductive strip (4) is a column with a coating on its surface, and its length is greater than or equal to the length of the battery substrate (1) in the same direction; The cross section of the conductive strip (4) is a circle with a diameter of 0.1 to 0.5 mm, or a rectangle with a width of 1.5 to 3 mm and a thickness of 0.1 to 0.2 mm.

4. The solar cell negative spacing unit according to claim 1, characterized in that: The conductive strip (4) is a cylinder, consisting of a plurality of thin cylinders with a diameter of 0.05 to 0.1 mm, whose outer walls are connected to each other, and a coating is provided on the surface of each thin cylinder; or the conductive strip (4) is a strip, consisting of a plurality of thin cylinders with a diameter of 0.05 to 0.1 mm, whose outer walls are connected in sequence, and a coating is provided on the surface of each thin cylinder.

5. A solar cell negative spacing unit according to any one of claims 1 to 4, characterized in that: The coating of the conductive strip (4) is a low-temperature alloy or a conductive resin; The thickness of the low-temperature alloy is 1 to 30 μm.

6. The solar cell negative spacing unit according to claim 5, characterized in that: The light-receiving surface welding strip (21) and the back-light-receiving surface welding strip (22) are both cylinders provided with a coating, the radial cross-sectional diameter D1 of the light-receiving surface welding strip (21) is less than or equal to the radial cross-sectional diameter D2 of the back-light-receiving surface welding strip (22), the values of D1 and D2 are 0.05 to 0.15 mm, and the coating of the light-receiving surface welding strip (21) and the back-light-receiving surface welding strip (22) is an alloy or a conductive resin.

7. The solar cell negative spacing unit according to claim 2, characterized in that: The elastic material (6) is one of POE, UV glue, and silicone rubber, with a thickness of 0.2 to 3 mm and a Shore hardness of 15 to 40.

8. The solar cell negative spacing unit according to claim 7, characterized in that: The elastic material (6) corresponds in shape and position to all light-receiving surface welding strips (21) of the light-receiving overlapping area (31), or is in the shape of a rectangle with a length consistent with the length of the battery substrate (1) in the same direction and a width of 0.2 to 2 mm.

9. The solar cell negative spacing unit according to claim 8, characterized in that: The adhesive film (5) is one of POE, EPE, and PVB.

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