Photovoltaic cell string, photovoltaic module and method for preparing photovoltaic module

Abstract

The present application provides a photovoltaic cell string, a photovoltaic module and a method for preparing a photovoltaic module, wherein the cell string comprises at least a first cell and a second cell, wherein the first end of the first cell is adjacent to the second end of the second cell and there is a gap between the first end and the second end, a first support portion is provided on the front side of the first end and / or a second support portion is provided on the back side of the second end, the first support portion and the second support portion are used to limit relative displacement of the cell sheets, and support portions are provided at both adjacent ends of two cell sheets to provide support for the cell sheets, thereby preventing the cell sheets from being close to each other during lamination or actual use and compressing the welding strips, causing hidden cracks in the cell sheets; at the same time, the welding strips between the cell sheets do not need to be bent, so that the gap between the cell sheets can be further reduced relative to that of a traditional small-pitch photovoltaic cell string, and there is no overlapping area between the cell sheets, so that the power generation performance of the cell sheets will not be wasted.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic manufacturing, and in particular to a photovoltaic cell string, a photovoltaic module and a method for preparing the photovoltaic module. Background Art

[0002] The high-density arrangement of cells within photovoltaic modules can increase the power generation per unit area of ​​the modules and reduce the LCOE (levelized cost of electricity) of power station installations. The main technical directions for achieving high-density arrangement of cells in the industry are stack welding and small pitch.

[0003] Figure 1 It shows a conventional photovoltaic cell string structure, where the cells 1 and 3 are connected in series via a welding ribbon 2, the width of the gap 4 between the cells is usually about 2 mm, and the arrangement density of the cells is very low.

[0004] Figure 2 A stacked photovoltaic cell string structure is shown, where the cell 1 and the cell 3 are connected in series via a welding ribbon 2, and the cell 1 and the cell 3 have an overlapping area 16, the width of the overlapping area 16 is usually about 0.5 mm. Figure 1 The conventional structure shown improves the arrangement density of the battery, but after overlapping, the battery cell 3 will be blocked by the light of the battery cell 1, so the edge portion of the battery cell 3 will not have the power generation function, resulting in a waste of the power generation performance of the battery cell 3.

[0005] Figure 3 A small-pitch photovoltaic cell string structure is shown, where cells 1 and 3 are connected in series via a soldering ribbon 2, and the soldering ribbon in the gap 4 between the cells is flattened to allow cells 1 and 3 to be closer together. Normally, the width of the gap 4 of the small-pitch photovoltaic cell string is about 0.8 mm.

[0006] However, if Figure 3 The small-pitch photovoltaic cell string structure shown can reduce the spacing between cell pieces compared to the conventional photovoltaic cell string structure, but there is still a gap compared to the zero spacing that can be achieved by the stack-welded photovoltaic cell string; at the same time, the welding ribbon in the gap 4 needs to be bent into the shape of the bending zone 5, which affects the accuracy of cell slicing, welding ribbon bending and string welding; when the photovoltaic cell string is in use, the welding ribbon will expand and contract due to changes in outdoor temperature, which will cause pulling of the cell piece and cause hidden cracks at the edge of the cell piece. Summary of the invention

[0007] In order to solve the deficiencies of the prior art, the main purpose of the present invention is to provide a photovoltaic cell string, a photovoltaic module and a method for preparing a photovoltaic module.

[0008] In order to achieve the above-mentioned objectives, in the first aspect, the present invention provides a photovoltaic cell string, comprising at least a first cell sheet and a second cell sheet, wherein the grid line on the front side of the first cell sheet is connected to the grid line on the back side of the second cell sheet by a welding strip, the first end of the first cell sheet is adjacent to the second end of the second cell sheet and there is a gap between the first end and the second end, a first supporting portion is provided on the front side of the first end and / or a second supporting portion is provided on the back side of the second end, and the first supporting portion and the second supporting portion are used to limit the relative displacement of the first cell sheet and the second cell sheet.

[0009] In some embodiments, the first supporting portion and the second supporting portion are formed by a gasket strip, and the gasket strip is ethylene vinyl acetate copolymer EVA or polyolefin thermoplastic elastomer POE.

[0010] In some embodiments, the first supporting portion and the second supporting portion are formed by a whole gasket strip, and the gasket strip is ethylene-vinyl acetate copolymer EVA or polyolefin thermoplastic elastomer POE.

[0011] In some embodiments, a hole is provided on the cushion strip, and a position of the hole corresponds to a position of the welding strip between the first end and the second end.

[0012] In some embodiments, the width of the gap does not exceed 0.5 mm.

[0013] In some embodiments, the welding strip in the gap is in the shape of a strip, and the thickness ranges from 0.05 mm to 0.25 mm.

[0014] In a second aspect, the present application provides a photovoltaic assembly, comprising the photovoltaic cell string as described above.

[0015] In a third aspect, the present application provides a method for preparing a photovoltaic module, wherein the photovoltaic module includes a photovoltaic cell string, and the photovoltaic cell string includes at least a first cell sheet and a second cell sheet, and the method includes:

[0016] Connecting the grid line on the front side of the first battery cell to the grid line on the back side of the second battery cell through a welding strip, wherein the first end of the first battery cell is adjacent to the second end of the second battery cell and there is a gap between the first end and the second end;

[0017] Disposing a cushion strip on the front side of the first end and / or the back side of the second end;

[0018] The first battery cell and the second battery cell are laminated, and the cushion strip is melted to form a first support portion on the front surface of the first end and / or a second support portion on the back surface of the second end to limit relative displacement of the first battery cell and the second battery cell.

[0019] In some embodiments, the cushion strip includes a first cushion strip and a second cushion strip, and the step of providing the cushion strips on the front side of the first end and the back side of the second end includes:

[0020] connecting the first furring strip to a front face of the first end;

[0021] The first battery sheet and the second battery sheet are turned over at a preset angle, and the second cushion strip is connected to the reverse side of the second end.

[0022] In some embodiments, the cushion strip includes a third cushion strip, the width of the third cushion strip is greater than the width of the gap, and the step of providing the cushion strips on the front side of the first end and the back side of the second end includes:

[0023] causing a preset relative displacement between the first end and the second end so as to lay a third cushion strip in the gap;

[0024] The first battery sheet and the second battery sheet are restored to the positions before the preset relative displacement, so that the third cushion strip contacts the front surface of the first end and the back surface of the second end.

[0025] The beneficial effects achieved by the present invention are:

[0026] The present application provides a photovoltaic cell string, comprising at least a first cell and a second cell, wherein a grid line on the front side of the first cell is connected to a grid line on the back side of the second cell by a welding strip, a first end of the first cell is adjacent to a second end of the second cell and a gap is provided between the first end and the second end, a first support portion is provided on the front side of the first end and / or a second support portion is provided on the back side of the second end, the first support portion and the second support portion are used to limit the relative displacement of the first cell and the second cell, and by respectively providing support portions at the two adjacent ends of the two cell sheets, support can be provided to the cell sheets respectively, so as to prevent the cell sheets from being close to each other during lamination or actual use and causing compression on the welding strip, thereby causing hidden cracks in the cell sheets; at the same time, no bent welding strip is required between the cell sheets, so that the gap between the cell sheets can be further reduced compared with the traditional small-pitch photovoltaic cell string structure, and there is no overlapping area between the cell sheets, so that the power generation performance of the cell sheets will not be wasted;

[0027] Furthermore, the present application proposes that the shape of the welding ribbon in the gap is a strip, and the thickness ranges from 0.05mm to 0.25mm. The pre-flattened welding ribbon replaces the bent welding ribbon in the gap of the traditional small-pitch photovoltaic cell string, thereby avoiding the problem of the bent welding ribbon pulling the battery cell and causing hidden cracks at the edge of the battery cell.

[0028] Not all products of the present invention need to have all the above effects. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0030] Figure 1 This is a diagram of a conventional photovoltaic cell string structure provided in an embodiment of the present application;

[0031] Figure 2 This is a structural diagram of a stack-welded photovoltaic cell string provided in an embodiment of the present application;

[0032] Figure 3 This is a structural diagram of a small-pitch photovoltaic cell string provided in an embodiment of the present application;

[0033] Figure 4 is a structural diagram of an improved photovoltaic cell string provided in an embodiment of the present application;

[0034] Figure 5 is a structural diagram of an improved photovoltaic cell string provided in an embodiment of the present application;

[0035] Figure 6 It is a structural diagram of a photovoltaic cell string provided with a cushion strip provided in an embodiment of the present application;

[0036] Figure 7 This is a schematic diagram of photovoltaic cell string heating provided in an embodiment of the present application;

[0037] Figure 8 is a schematic diagram of photovoltaic module lamination provided in an embodiment of the present application;

[0038] Fig. 9 It is a structural diagram of a photovoltaic cell string provided with a cushion strip provided in an embodiment of the present application;

[0039] Fig.10 This is a schematic diagram of laying cushion strips provided in an embodiment of the present application;

[0040] Fig.11 is a schematic diagram of preheating the pad provided in an embodiment of the present application;

[0041] Fig.12 It is a schematic diagram of the structure of a gasket strip provided with holes provided in an embodiment of the present application;

[0042] Fig.13 It is a structural diagram of a photovoltaic cell string provided with a cushion strip provided in an embodiment of the present application;

[0043] Fig.14 It is a structural diagram of a photovoltaic cell string provided with a cushion strip provided in an embodiment of the present application;

[0044] Fig.15 It is a structural diagram of a photovoltaic cell string provided with a cushion strip provided in an embodiment of the present application;

[0045] Fig.16 is a schematic diagram of photovoltaic module lamination provided in an embodiment of the present application;

[0046] Fig.17 This is a schematic diagram of the lamination of photovoltaic modules provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0048] As described in the background technology, the existing small-pitch photovoltaic cell strings have many disadvantages. To solve the above problems, the present application provides a photovoltaic cell string, such as Figure 4 As shown, at least a battery cell 1 and a battery cell 3 are included, the grid line on the front side of the battery cell 3 is connected to the grid line on the back side of the battery cell 1 through a welding strip 2, the first end 12 of the battery cell 3 is adjacent to the second end 13 of the battery cell 1 and there is a gap between the first end 12 and the second end 13, a first support portion 6 is provided on the front side of the first end 12, and a second support portion 14 is provided on the back side of the second end, and the first support portion 6 and the second support portion 14 are used to limit the relative displacement of the battery cell 1 and the battery cell 3.

[0049] The photovoltaic cell string according to the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0050] Embodiment 1

[0051] like Figure 4 As shown, the photovoltaic cell string provided in the present application comprises at least a cell 1 and a cell 3, the grid line on the front side of the cell 3 is connected to the grid line on the back side of the cell 1 through a welding strip 2, the first end 12 of the cell 3 is adjacent to the second end 13 of the cell 1 and there is a gap 4 between the first end 12 and the second end 13, a first support portion 6 is provided on the front side of the first end 12 and a second support portion 14 is provided on the back side of the second end 13, and the first support portion 6 and the second support portion 14 are used to limit the relative displacement of the cell 1 and the cell 3. The front side of the cell refers to the side of the cell used to absorb solar energy, and the back side of the cell is the opposite side of the front side.

[0052] like Figure 5As shown, the back side of the battery cell 3 can also be connected to the front side of the battery cell 1 through the welding ribbon 2, and then the second support portion 14 is arranged on the back side of the battery cell 3 and the first support portion 6 is arranged on the front side of the battery cell 1.

[0053] Specifically, the preparation process of the photovoltaic module including the photovoltaic cell string includes:

[0054] Step 1: Connect the grid line on the front side of the battery cell 3 to the grid line on the back side of the battery cell 1 through the welding ribbon 2, wherein the first end 12 of the battery cell 3 is adjacent to the second end 13 of the battery cell 1 and there is a gap 4 between the first end 12 and the second end 13;

[0055] like Figure 4 As shown, the solder strip in the gap does not need to be bent. Preferably, in order to reduce the distance between the back of the battery cell 1 and the front of the battery cell 3, the solder strip in the gap can be pre-flattened. Preferably, the thickness of the flattened solder strip is in the range of 0.05-0.25mm. The width of the gap 4 should not exceed 1.5mm, preferably not more than 0.5mm.

[0056] Step 2: Arrange a cushion strip on the front side of the first end 12 and the back side of the second end 13;

[0057] like Figure 6 As shown, the battery cell 1 and the battery cell 3 are connected in series via the welding ribbon 2. A gasket 15 may be provided on the reverse side of the second end 13 of the battery cell 1 and a gasket 15 may be provided on the front side of the first end 12 of the battery cell 3.

[0058] The material of the gasket strip 15 can be any material that is similar to and compatible with the packaging film of the photovoltaic module, such as ethylene-vinyl acetate copolymer EVA, polyolefin thermoplastic elastomer POE, etc.

[0059] The length of the pad should be greater than the distance between the two most distant solder strips among all solder strips, and the thickness of the pad should be greater than the thickness of the battery cell. Preferably, the thickness of the pad can be greater than the sum of the thickness of the battery cell and the solder strip. Preferably, the width of the pad is in the range of 5-30 mm.

[0060] like Figure 7 As shown, the photovoltaic cell string includes a cell 1 and a cell 3 connected by a welding ribbon 2. The pad can be set on the cell, and then the pad 15 can be heated by a heating device 7 to partially melt it so as to connect it to the cell, and then the cell string is flipped to a preset angle, and another pad is set on the cell string and heated to partially melt it so as to connect it to the cell, so as to avoid the pad falling off during the subsequent processing of the cell string. The heating device 7 includes but is not limited to any heating device such as a soldering iron, hot air, infrared and a heating rod, and this application does not limit this.

[0061] Preferably, the preset angle has a value range of 180°+ / -15°.

[0062] Step 3, laminating battery cell 1 and battery cell 3;

[0063] like Figure 8 As shown, before lamination, the photovoltaic cell string including the cell 1 and the cell 3 can be flipped to a preset angle, and the photovoltaic cell string can be encapsulated on the glass substrate 8 of the photovoltaic module including the photovoltaic cell string through the encapsulation film 10. During lamination, the lamination pressure will be transmitted to the photovoltaic cell string wrapped in the encapsulation film 10 through the backplane 9. The backplane 9 can be any structure such as a polymer structure backplane or a glass plate of a photovoltaic module, and this application does not limit this. During the lamination process, the cushion strip will melt to form the first support portion 6 and the second support portion 14 respectively, and at the same time fill the gap in the encapsulation film 10. As shown in FIG. Figure 8 As shown by the left arrow in FIG. 1 , the first support portion 6 can provide an upward support force to the battery cell 3 to prevent it from being displaced relative to the battery cell 1 due to the lamination pressure; Figure 8 As shown by the right arrow in the figure, the second support portion 14 can provide downward pressure on the battery cell 1 to prevent it from being displaced relative to the battery cell 3 due to the lamination pressure, thereby preventing the battery cells from gradually approaching each other due to the lamination pressure, causing pressure on the welding strip 2 and causing hidden cracks on the edges of the battery cells.

[0064] When photovoltaic modules are installed and used outdoors, since the welding ribbon in the gap is not bent, when the welding ribbon changes due to high and low temperature stress, it will not generate pulling force on the edge of the battery cell, and will not cause hidden cracks on the edge of the battery cell.

[0065] Embodiment 2

[0066] In order to improve the laying efficiency of the mat strips, two mat strips can be processed into one mat strip in advance so that the laying can be completed in one go. Fig. 9 As shown, the battery cell 1 and the battery cell 3 are connected by a welding strip, and the pad 15 is arranged in the gap between the two battery cells. Fig.10 As shown, when laying the cushion strip, the battery cell 1 and the battery cell 3 can be relatively displaced to separate the two ends of the two battery cells, and then the cushion strip 15 is picked up by the picking device 11 and laid on the gap. Fig.11 As shown, the width of the gasket strip is greater than the width of the gap, so it covers the back side of the second end of the battery cell 1 and the front side of the first end of the battery cell 3. The heating device 7 can be used to heat the gasket strip 15 to partially melt it and connect it to the battery cell 1 and / or the battery cell 3 to prevent the gasket strip from being displaced or falling off during subsequent processing.

[0067] During lamination, the cushion strip will melt and form a second supporting portion on the back side covering the second end of the battery cell 1 and a first supporting portion on the front side covering the first end of the battery cell 3 .

[0068] In order to reduce material costs, such as Fig.12 As shown, one or more holes may be opened on the gasket strip 15, and the position of each hole corresponds to the position of the welding strip on the battery cell. Fig.13 A photovoltaic cell string is shown with a mat strip 15 having holes therein laid.

[0069] Embodiment 3

[0070] In order to reduce material costs, a cushion strip may be laid on one of the front surface of the first end or the back surface of the second end.

[0071] like Fig.14 As shown, the cushion strip 15 can be laid only on the front side of the first end 12 of the battery cell 3. Fig.15 As shown, the cushion strip 15 may also be laid only on the back side of the second end of the battery cell 1. Figure 7 As shown, the heating device 7 can be used to heat the gasket 15 so that it partially melts and connects to the second end of the battery cell 1 or the first end of the battery cell 3 .

[0072] Fig.16 The lamination schematic diagram is shown when the cushion strip is arranged on the reverse side of the second end of the cell 1. Before lamination, the photovoltaic cell string including the cell 1 and the cell 3 can be flipped at a preset angle, and the photovoltaic cell string is encapsulated on the glass substrate 8 of the photovoltaic module including the photovoltaic cell string through the encapsulation film 10. During lamination, the lamination pressure will be transmitted to the photovoltaic cell string wrapped in the encapsulation film 10 through the back sheet 9, and the support portion formed by the melting of the cushion strip will provide a downward squeezing force on the cell 1, keeping it away from the cell 3 to avoid pressing the welding ribbon 2.

[0073] Fig.17 The lamination schematic diagram is shown when the cushion strip is arranged on the front side of the first end of the cell 3. Before lamination, the photovoltaic cell string including the cell 1 and the cell 3 can be flipped at a preset angle, and the photovoltaic cell string is encapsulated on the glass substrate 8 of the photovoltaic module including the photovoltaic cell string through the encapsulation film 10. During lamination, the support portion formed by the melting of the cushion strip 15 will provide an upward support force for the cell 3, preventing it from moving in the direction close to the cell 1, which can ensure that the spacing between the cells is sufficient during lamination, and avoid the cells being close to each other due to the lamination pressure, which will compress the welding strip 2 and cause hidden cracks at the edge of the cell.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A photovoltaic cell string, comprising at least a first cell and a second cell, characterized in that: The grid lines on the front side of the first battery cell and the grid lines on the back side of the second battery cell are connected by welding strips, the first end of the first battery cell is adjacent to the second end of the second battery cell, and there is a gap between the first end and the second end, and there is no overlapping area between the battery cells; a first supporting portion is provided on the front side of the first end and a second supporting portion is provided on the back side of the second end, the first supporting portion does not completely cover the front side of the entire first battery cell, and the second supporting portion does not completely cover the back side of the entire second battery cell; during lamination, the first supporting portion and the second supporting portion melt and are used to limit the relative displacement of the first battery cell and the second battery cell; The first supporting portion and the second supporting portion are formed by a whole pad strip, the pad strip is provided with a hole, the position of the hole corresponds to the position of the welding strip between the first end and the second end; the width of the pad strip is greater than the gap between the first end and the second end, the pad strip covers the front surface of the first end and the back surface of the second end, the pad strip is partially melted under the action of the heating device and connected to the first battery cell and the second battery cell; during lamination, the pad strip melts and covers the front surface of the first end and the back surface of the second end; The shape of the welding strip in the gap is strip-shaped; The soldering strips in the gaps are flattened in advance before connection.

2. The photovoltaic cell string according to claim 1, characterized in that: The cushion strip is ethylene-vinyl acetate copolymer EVA or polyolefin thermoplastic elastomer POE.

3. The photovoltaic cell string according to any one of claims 1-2, characterized in that: The width of the gap does not exceed 0.5 mm.

4. The photovoltaic cell string according to any one of claims 1-2, characterized in that: The thickness of the welding strip ranges from 0.05mm to 0.25mm.

5. A photovoltaic module, characterized in that: It comprises a photovoltaic cell string as described in any one of claims 1 to 4.

6. A method for preparing a photovoltaic module, the photovoltaic module comprising a photovoltaic cell string, the photovoltaic cell string comprising at least a first cell sheet and a second cell sheet, characterized in that: The method comprises: Connecting the grid line on the front side of the first battery cell to the grid line on the back side of the second battery cell through a welding strip, wherein the first end of the first battery cell is adjacent to the second end of the second battery cell and there is a gap between the first end and the second end, and there is no overlapping area between the battery cells; A cushion strip is provided on the front side of the first end and the back side of the second end; The first battery cell and the second battery cell are laminated, the cushion strip is melted to form a first support portion on the front surface of the first end and a second support portion on the back surface of the second end, so as to limit the relative displacement of the first battery cell and the second battery cell; the first support portion does not completely cover the front surface of the entire first battery cell, and the second support portion does not completely cover the back surface of the entire second battery cell; The first supporting portion and the second supporting portion are formed by a whole pad strip, the pad strip is provided with a hole, the position of the hole corresponds to the position of the welding strip between the first end and the second end; the width of the pad strip is greater than the gap between the first end and the second end, the pad strip covers the front surface of the first end and the back surface of the second end, the pad strip is partially melted under the action of the heating device and connected to the first battery cell and the second battery cell; during lamination, the pad strip melts and covers the front surface of the first end and the back surface of the second end; The shape of the welding strip in the gap is strip-shaped; The soldering strips in the gaps are flattened in advance before connection.

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