A flexible and rollable back-contact solar cell module and its preparation method

Abstract

The present invention provides a flexible and rollable back-contact solar cell module, the length of which can be extended indefinitely. The module is composed of a plurality of large battery blocks connected in series or in parallel; a large battery block is composed of a plurality of small battery strings connected in series or in parallel; a small battery string is composed of a plurality of small square battery slices connected in series or in parallel; the large battery blocks, small battery strings, and small square battery slices are connected in series or in parallel with each other by welding with flexible interconnection strips in a horizontal or vertical direction. The electrodes of the small square battery slices are all on the back side, and are cut from back-contact solar cells, and the light-receiving surface is adhered to a protective layer with an adhesive layer. At the same time, during preparation, the solar cells and the protective layer are pre-cut and then adhered, and then the fragments are processed. The back-contact solar cell module can realize the free combination of large battery blocks in series, in parallel, or in series and parallel according to actual application requirements, and the electrodes do not block the light-receiving surface, making the design more flexible, the processing more convenient, and the light utilization rate higher.

Description

Technical Field

[0001] The present invention relates to the field of solar cell preparation, and in particular to a flexible and rollable IBC or HBC back-contact solar cell module and a preparation method thereof. Background Art

[0002] Previous generations of flexible solar cell modules were manufactured by cutting solar cell chips into numerous small cells and then laminating and protecting them on the surface of the small cells. However, due to the small size of the small cells, the lamination and protection layer required high precision, resulting in a high number of defects. Furthermore, the positive and negative electrodes of the small cells that make up the flexible solar panel are on different sides of the cell. During production, the positive and negative electrodes of the small cells must be serially soldered. This requires soldering the positive or negative side, then flipping it over and soldering the other side, or laying interconnecting strips on both sides of the small cell and soldering them simultaneously. Due to the small size of the small cells that make up the flexible assembly, the required process is very precise and difficult to manufacture. Furthermore, the small cells are welded in a uniform horizontal direction, which limits the design of the flexible battery assembly. Furthermore, because the cells have electrodes on both the light-receiving and backside surfaces, the interconnecting strips after serial soldering can block the power generation surface, reducing power generation efficiency.

[0003] The most notable feature of back-contact solar cells (IBC and HBC) is that the PN junction and metal contacts are located on the back of the solar cell. This completely eliminates the front surface from obstruction by metal grid electrodes and interconnecting strips for welding electrodes. This maximizes the use of incident light, reduces optical losses, and achieves higher short-circuit current. Furthermore, the presence of both the positive and negative electrodes on the back of the cell further improves process efficiency during the welding of small cells. This unobstructed front solar cell not only offers high conversion efficiency but also boasts an aesthetically pleasing appearance. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention provides a flexible, rollable back-contact solar cell module. The module is characterized by being infinitely extendable and composed of multiple large battery blocks connected in series or in parallel; the large battery blocks are composed of multiple small battery strings connected in series or in parallel; the small battery strings are composed of multiple small square battery cells connected in series or in parallel; and the large battery blocks, small battery strings, and small square battery cells are connected in series or in parallel using horizontal or vertical flexible interconnecting strips. The electrodes of the small square battery cells are all on the back side and are cut from back-contact solar cells. The light-receiving surface is bonded with a protective layer of adhesive.

[0005] To obtain the back-contact solar cell module, the present invention adopts the following technologies:

[0006] Pre-cutting the back contact solar cells and protective layers to form multiple small square cells and small square protective layers that are not completely disconnected;

[0007] Use an adhesive layer to bond the light-receiving surface of the back-contact solar cell and the protective layer together;

[0008] The fragments are processed to form multiple small square cells with protective layers attached to the light-receiving surfaces;

[0009] Use automatic chip splitting and arranging equipment to arrange multiple small square battery cells, and use high-temperature tape to stick to the middle of the back to fix the position of the small square battery cells. Then use flexible interconnection strips to weld them in series or parallel to form a small battery string;

[0010] Arrange multiple strings of small batteries and then weld them in series or in parallel through flexible interconnecting strips to form a large battery block;

[0011] According to the design requirements, multiple large battery blocks are welded in series or in parallel through flexible interconnection strips to form a back-contact solar cell module.

[0012] Preferably, the infinitely extended back-contact solar cell module can also be cut at a suitable position according to design requirements, re-formed into multiple large cells, and then re-connected in series and parallel via flexible interconnection strips to form a solar cell module that meets the new design requirements.

[0013] Preferably, when the back-contact solar cell module is formed by connecting large battery blocks in series, the positive and negative electrodes of the large battery blocks are connected by flexible interconnecting strips in a horizontal direction.

[0014] Preferably, when the back-contact solar cell module is formed by connecting large battery blocks in parallel, vertical flexible interconnection strips are used to connect the positive electrodes and the negative electrodes of the large battery blocks.

[0015] Preferably, the small square battery cells have a length of 1-100 mm and a width of 1-100 mm, and a certain distance is maintained between the small square battery cells.

[0016] Preferably, the flexible interconnection strip is a 0.1-20 mm FCCL soft solder strip or FPCB or a flexible tinned copper strip, and the gap between the small battery strings connected by the flexible interconnection strip is 0.1-5 mm.

[0017] Preferably, the protective layer is a hard material layer, which may be glass, PC, PMMA, PP, PET or a transparent fluorine material layer, and has a thickness of 0.2-2 mm.

[0018] Preferably, the bonding adhesive layer between the small square battery cell and the protective layer is made of silicone, EVA adhesive, POE adhesive, double-sided adhesive, etc., and is cured by UV light or high temperature.

[0019] Preferably, the back-contact solar cell is an interdigitated back-contact (IBC) solar cell or an interdigitated back-contact heterojunction (HBC) solar cell.

[0020] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following advantages:

[0021] The back-contact solar cell module provided by the present invention can be extended indefinitely, and the large battery blocks constituting the back-contact solar cell module can be freely combined in series, in parallel, or in series and parallel by utilizing flexible interconnection strips in both horizontal and vertical directions according to actual application requirements; and by pre-cutting the back-contact solar cells and the protective layer, and then processing the fragments after the adhesive layer is bonded, the design of the solar cell module is more flexible and the processing is more convenient. Furthermore, the electrodes of the back-contact solar cell module are all on the back, which is convenient for welding the flexible interconnection strips and will not block the light-receiving surface, thereby effectively improving the light utilization rate. In addition, because the back-contact solar cell module provided by the present invention can be extended indefinitely, the back-contact solar cell module provided by the present invention can also realize the design of solar cell modules with different current and voltage requirements at any width size. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 A schematic cross-sectional view of the back-contact solar cell module provided by the present invention;

[0024] Figure 2 A schematic diagram of the front structure of a back-contact solar cell module according to an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of cutting the back-contact solar cell provided by the present invention into small square cells;

[0026] Figure 4 This is a schematic diagram of the structure of the back-contact solar cell provided by the present invention, which is bonded to hard glass and then scribed into small square cells;

[0027] Figure 5 This is a schematic diagram of the structure of the small square battery cells provided by the present invention arranged into small battery strings and affixed with high-temperature tape on the back side;

[0028] Figure 6 This is a schematic diagram of the structure of two small battery strings provided by the present invention arranged in parallel;

[0029] Figure 7This is a schematic diagram of the structure after the flexible interconnection strip is welded on the back side between two strings of small batteries provided by the present invention;

[0030] Figure 8 This is a schematic cross-sectional view of two small battery strings provided by the present invention connected in series via a flexible interconnection strip;

[0031] Figure 9 A schematic structural diagram of a large battery block provided by the present invention;

[0032] Figure 10 A schematic diagram of the structure of two large battery blocks provided by the present invention being welded together via flexible interconnection strips;

[0033] Figure 11 A schematic structural diagram of the infinitely extendable back-contact solar cell module provided by the present invention, which is cut at a suitable position according to design requirements. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] Figure 1 and 2 As shown, the present invention provides a flexible, rollable back-contact solar cell module. The module can be extended indefinitely and consists of multiple large battery blocks 10 connected in series or in parallel. The large battery blocks 10 are composed of multiple small battery strings 7 connected in series or in parallel. The small battery strings 7 are composed of multiple small square battery cells 2 connected in series or in parallel. The large battery blocks 10, small battery strings 7, and small square battery cells 2 are connected in series or in parallel using horizontal or vertical flexible interconnecting strips 8. The electrodes of the small square battery cells 2 are all on the back side and are cut from back-contact solar cells 1. The light-receiving surface is bonded to a protective layer 4 with an adhesive layer 3.

[0036] The back contact solar cell module preparation process is as follows:

[0037] First, the back contact solar cell 1 and the protective layer 4 are pre-cut to form a plurality of small square solar cells 2 and small square protective layers 4 that are not completely disconnected; Figure 3 As shown, the back contact solar cell 1 is an interdigitated back contact heterojunction (HBC) solar cell. The cut small square cell 2 has a length of 12.0 mm and a width of 8.0 mm, and the positive and negative electrodes of the small square cell are both on the back of the cell.

[0038] Next, the light-receiving surface of the back-contact solar cell 1 and the protective layer 4 are bonded together using an adhesive layer 3; wherein the adhesive layer 3 is optical silicone, which is cured at high temperature; and the protective layer 4 is a hard material, transparent glass, with a thickness of 0.4 mm.

[0039] Next, the back contact solar cells 1 after bonding are fragmented to form a plurality of small square solar cells 2 with a protective layer bonded to the light-receiving surface;

[0040] Figure 4 and 5 As shown, a chip automatic cracking and arranging device is used to arrange 20 small square battery cells 2 in each string with a spacing of 0.4 mm. A high-temperature tape 6 is attached to the middle of the back to fix the position of the small square battery cells 2. Then, a flexible interconnection strip 8 is used to weld them in series or in parallel to form a small battery string 7.

[0041] Figure 9 As shown, 13 small battery strings 7 are arranged and then welded in series through flexible interconnection strips 8 to form a large battery block 10. Flexible interconnection strips 8 are welded to the positive and negative electrodes of the outermost small battery string 7 to connect the other large battery blocks in series and parallel. The small battery strings 7 are spaced 0.2 mm apart. Figure 6 As shown), the positive and negative electrodes of the two small battery strings 7 are welded in series with flexible interconnection strips 8 ( Figure 7 and 8 shown).

[0042] Figure 10 As shown, according to design requirements, two large battery blocks 10 are welded in parallel through flexible interconnection strips 8 to form a back-contact solar cell module.

[0043] Figure 11 As shown, after a plurality of large battery blocks 10 are connected in series or in parallel to form a back-contact solar cell module, they can be cut at required positions and reconnected in series or welded in parallel via flexible interconnection strips to re-form a back-contact solar cell module according to design requirements.

[0044] The back-contact solar cell module provided by the present invention can be extended indefinitely, and the large battery blocks constituting the back-contact solar cell module can be freely combined in series, in parallel, or in series and parallel by utilizing flexible interconnection strips in both the horizontal and vertical directions according to actual application requirements. Moreover, by pre-cutting the back-contact solar cells and the protective layer, and then processing the fragments after the adhesive layer is bonded, the design of the solar cell module is more flexible and the processing is more convenient. Furthermore, the electrodes of the back-contact solar cell module are all on the back, which is convenient for welding the flexible interconnection strips and will not block the light-receiving surface, thereby effectively improving the light utilization rate. In addition, because the back-contact solar cell module provided by the present invention can be extended indefinitely, the back-contact solar cell module provided by the present invention can also realize the design of solar cell modules with different current and voltage requirements at any width size.

[0045] 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 and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flexible and rollable back-contact solar cell module, characterized by: The back-contact solar cell module can be extended indefinitely and is composed of multiple large battery blocks connected in series or in parallel; the large battery blocks are composed of multiple small battery strings connected in series or in parallel; the small battery strings are composed of multiple small square battery cells connected in series or in parallel; the large battery blocks, small battery strings, and small square battery cells are connected in series or in parallel by welding with flexible interconnection strips in a horizontal or vertical direction; the electrodes of the small square battery cells are all on the back side and are cut from back-contact solar cells, and the light-receiving surface is adhered with a protective layer with an adhesive layer. The back-contact solar cell module adopts the following technologies: Pre-cutting the back contact solar cells and protective layers to form multiple small square cells and small square protective layers that are not completely disconnected; Use an adhesive layer to bond the light-receiving surface of the back-contact solar cell and the protective layer together; The fragments are processed to form multiple small square cells with protective layers attached to the light-receiving surfaces; Use automatic chip splitting and arranging equipment to arrange multiple small square battery cells, and use high-temperature tape to stick to the middle of the back to fix the position of the small square battery cells. Then use flexible interconnection strips to weld them in series or parallel to form a small battery string; Arrange multiple strings of small batteries and then weld them in series or in parallel through flexible interconnecting strips to form a large battery block; According to the design requirements, multiple large battery blocks are welded in series or in parallel through flexible interconnection strips to form a back-contact solar cell module; When the back contact solar cell module is formed by connecting large battery blocks in series, the positive and negative electrodes of the large battery blocks are connected by horizontal flexible interconnection strips; When the back contact solar cell module is formed by connecting large battery blocks in parallel, the positive electrodes and negative electrodes of the large battery blocks are connected by flexible interconnecting strips in a vertical direction.

2. The back-contact solar cell module according to claim 1, further characterized by: The back-contact solar cell module can also be cut at a suitable position according to design requirements to re-form multiple large cells, which are then re-connected in series and parallel via flexible interconnection strips to form a solar cell module that meets new design requirements.

3. The back contact solar cell module according to claim 1 or 2, characterized in that: The length of the small square battery cells is 1-100 mm, the width is 1-100 mm, and the small square battery cells maintain a certain distance from each other.

4. The back contact solar cell module according to claim 1 or 2, characterized in that: The flexible interconnection strip is a 0.1-20mm FCCL soft solder strip or FPCB or flexible tinned copper strip. The gap between the small battery strings connected by the flexible interconnection strip is 0.1-5mm. The small battery string consists of more than two small square batteries.

5. The back contact solar cell module according to claim 1 or 2, characterized in that: The protective layer is a hard material layer, which can be glass, PC, PMMA, PP, PET or a transparent fluorine material layer, and its thickness is 0.2-2 mm.

6. The back contact solar cell module according to claim 1 or 2, characterized in that: The bonding adhesive layer between the small square battery cell and the protective layer is made of silicone, EVA glue, POE glue, double-sided tape, etc., and is cured by UV light or high temperature.

7. The back-contact solar cell module according to claim 1 or 2, characterized in that: The back contact solar cell is an interdigitated back contact (IBC) solar cell or an interdigitated back contact heterojunction (HBC) solar cell.

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