Battery string, battery string preparation method and photovoltaic module

Abstract

The invention discloses a battery string, a battery string preparation method and a photovoltaic module, which are applied to the field of solar cells, the battery string comprises a plurality of battery pieces and solder strips for connecting adjacent battery pieces, each battery piece is provided with a middle area and edge areas located on two sides of the middle area along the extension direction of the solder strips, and the surface of each battery piece is provided with fine grids. The battery string further comprises an edge bearing film and a low-temperature welding disc which are arranged in the edge area, and the edge bearing film and the low-temperature welding disc are used for fixing the welding strip on the surface of the battery piece in advance. The edge bearing films and the low-temperature welding discs are arranged in the edge areas, located on the two sides of the middle area of the battery piece, of the battery piece in the extending direction of the welding strip, the two ends of the welding strip are pre-fixed through the edge bearing films and the low-temperature welding discs, and the contact yield of the edges of the welding strip can be increased.

Description

Technical Field

[0001] This invention relates to the field of solar cells, and particularly to a battery string, a method for preparing the battery string, and a photovoltaic module. Background Technology

[0002] With the development of solar cells and modules, cost reduction and efficiency improvement are the mainstream development directions in the industry. In non-silicon cost reduction, in order to reduce the amount of silver paste used, grid-less photovoltaic modules have been developed. Taking grid-less photovoltaic modules as an example, the solder ribbon contacts the fine grid to conduct the current generated by photoelectric conversion in the fine grid. In order to balance the stable connection between the solder ribbon and the fine grid and to avoid grid breakage, the current method is to lay the solder ribbon on the surface of the cell and lay a carrier film on the outside of the solder ribbon to fix the solder ribbon to the surface of the cell, so that the solder ribbon and the fine grid are fixedly connected at low temperature.

[0003] However, the method of fixing the carrier film by laying it on the outside of the solder strip is prone to moisture intrusion at the edge of the carrier film, which can lead to unstable connection at the edge of the carrier film. This can cause the edge of the solder strip to detach from the grid, reducing the yield of the module. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a battery string, a battery string preparation method and a photovoltaic module, which solves the problem in the prior art that uses a carrier film to fix the solder strip on the outside of the solder strip. This is because the edge of the carrier film is easily invaded by water vapor, which leads to unstable connection at the edge of the carrier film, and in turn, causes the edge of the solder strip to detach from the grid, thus reducing the yield of the module.

[0005] To solve the above-mentioned technical problems, the present invention provides a battery string, including a plurality of battery cells and a solder strip connecting adjacent battery cells. The battery cells have a central region and edge regions located on both sides of the central region along the extension direction of the solder strip. The surface of the battery cells has a fine grid. The battery string also includes an edge support film and a low-temperature welding pad disposed in the edge regions. The edge support film and the low-temperature welding pad are used to pre-fix the solder strip on the surface of the battery cells.

[0006] A fixed carrier film is used to cover the solder ribbon to pre-fix the solder ribbon to the surface of the battery cell.

[0007] Optionally, the low-temperature welding pad is disposed on the fine grid in the edge region.

[0008] Optionally, the low-temperature welding pad is disposed on a fine grid adjacent to the edge of the solar cell;

[0009] The edge-bearing membrane is located on the outside of the low-temperature welding pad.

[0010] Optionally, the edge support film is a strip-shaped edge support film disposed corresponding to the edge of the battery cell.

[0011] Optionally, the edge bearing film and the low-temperature welding pad are provided on both sides of the edge region; or,

[0012] One edge region has the edge support film and the low-temperature welding pad disposed on its front side, and the other edge region has the edge support film and the low-temperature welding pad disposed on its back side.

[0013] Optionally, the thickness of the edge-bearing membrane is 75 micrometers to 100 micrometers;

[0014] The low-temperature soldering pad is a low-temperature solder paste, and the thickness of the low-temperature solder paste is 20 to 50 micrometers thicker than the thickness of the edge carrier film.

[0015] Optionally, the fixed bearing film is a strip-shaped fixed bearing film.

[0016] Optionally, the strip-shaped fixed bearing film is laid in a direction perpendicular to the extension direction of the welding strip.

[0017] The present invention also provides a method for preparing a battery string, comprising:

[0018] Low-temperature welding pads are installed at the edge areas of the solar cells;

[0019] An edge-supporting film is applied to the edge area of ​​the battery cell;

[0020] The solder strip is laid on the surface of the battery cell and corresponds to the position of the edge support film and the low-temperature welding pad;

[0021] The fixing carrier film is placed on the battery cell and covered with the solder strip;

[0022] Heating fixes the solder ribbon to the surface of the battery cell and electrically connects the solder ribbon to the grid.

[0023] The present invention also provides a photovoltaic module, comprising:

[0024] The first encapsulation film, the second encapsulation film, the front plate, the back plate, and the battery string as described above;

[0025] The first encapsulating film and the second encapsulating film are respectively disposed on both sides of the battery string, and the front plate and the back plate are respectively disposed on the outer sides of the first encapsulating film and the second encapsulating film.

[0026] As can be seen, the battery string provided by the present invention includes a plurality of battery cells and solder strips connecting adjacent battery cells. Each battery cell has a central region and edge regions located on both sides of the central region along the extension direction of the solder strip. The surface of the battery cell has fine grids. The battery string also includes an edge support film and a low-temperature welding pad disposed in the edge regions. The edge support film and the low-temperature welding pad are used to pre-fix the solder strips to the surface of the battery cells. The present invention improves the contact yield of the solder strip edges by providing an edge support film and a low-temperature welding pad in the edge regions on both sides of the central region of the battery cell along the extension direction of the solder strip, and by using the edge support film and the low-temperature welding pad to pre-fix the two ends of the solder strip.

[0027] In addition, the present invention also provides a method for preparing a battery string and a photovoltaic module, which also have the above-mentioned beneficial effects. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a battery cell in a battery string provided by an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of an existing battery cell;

[0031] Figure 3 This is a schematic diagram of a battery cell without solder strips provided in this embodiment;

[0032] Figure 4 This is a schematic diagram of the structure of a battery cell in another battery string provided by an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of the structure of a battery cell in a battery string provided by an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of another battery string structure provided in an embodiment of the present invention;

[0035] Figure 7 A flowchart of a battery string fabrication method provided in an embodiment of the present invention;

[0036] Figure 8 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present invention;

[0037] Figures 1 to 6 ,as well as Figure 8 The reference numerals in the attached figures are explained as follows:

[0038] 1-Battery cell, 11-Grid, 20-Edge carrier film, 30-Low temperature welding pad, 40-Spindle, 50-Fixing carrier film, 60-Front panel, 70-First encapsulation film, 80-Second encapsulation film, 90-Back panel. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1:

[0041] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a battery cell in a battery string according to an embodiment of the present invention. The battery string includes a plurality of battery cells 1 and solder strips 40 connecting adjacent battery cells 1. Each battery cell 1 has a central region and edge regions located on both sides of the central region along the extension direction of the solder strips 40. The surface of the battery cell has fine grids. The battery string also includes an edge support film 20 and a low-temperature welding pad 30 disposed in the edge regions. The edge support film 20 and the low-temperature welding pad 30 are used to pre-fix the solder strips 40 to the surface of the battery cells 1.

[0042] A fixed carrier film 50 is used to cover the solder ribbon 40 to pre-fix the solder ribbon 40 to the surface of the battery cell 1.

[0043] In this embodiment, the battery cell 1 is generally configured as a rectangular battery cell. The fine grids 11 on the surface of the battery cell 1 are generally formed parallel to a set of edges of the battery cell 1. To facilitate current collection by the solder ribbon 40, the solder ribbon 40 is generally configured to be perpendicular to the fine grids 11 and conductive to all the fine grids 11 on the surface of the battery cell 1. The aforementioned fine grids 11 can be referenced from... Figure 2 , Figure 2 This is a schematic diagram of the structure of an existing battery cell. Figure 2The solar cell 1 is a solar cell without the solder ribbon 40. In this embodiment, the solar cell 1 is used in a process where a fixing carrier film 50 is laid on the side of the solder ribbon 40 facing away from the solar cell 1 to fix the solder ribbon 40 to the surface of the solar cell 1. Because the fixing carrier film 50 is typically smaller than the solar cell 1 in the process of fixing the solder ribbon 40 by laying it on the outside of the solder ribbon 40, and because there is a lack of pressure from a presser at the edge of the fixing carrier film 50 during the pre-fixation heating process, the ends of the solder ribbon 40 are prone to detachment. Therefore, it is necessary to fix the solder ribbon 40 at its edges to avoid this detachment. In this embodiment, the fixing carrier film 50 can be only placed in the middle area of ​​the surface of the solar cell 1. In this embodiment, the edge carrier film and low-temperature welding pad can also be placed in a portion of the edge area of ​​a portion of the solar cell. In this embodiment, the welding temperature required for the low-temperature welding pad is lower than the string welding temperature of solar cells in traditional photovoltaic modules.

[0044] In this embodiment, the edge region of the battery cell 1, located outside the middle region of the battery cell 1 at both ends along the extension direction of the solder ribbon 40, is the edge region of the battery cell 1. The edge support film 20 and the low-temperature welding pad 30 are correspondingly disposed in the edge region of the battery cell 1 to pre-fix the solder ribbon 40 to the surface of the battery cell 1 at both ends. The edge support film 20 and the low-temperature welding pad 30 are disposed between the solder ribbon 40 and the surface of the battery cell 1. This embodiment does not limit the specific location of the two ends of the battery cell 1 along the extension direction of the solder ribbon 40, as long as the edge support film 20 and the low-temperature welding pad 30, disposed after the solder ribbon 40 is laid, can further improve the fixing stability of the solder ribbon 40 at both ends. For example, it can refer to... Figure 3 , Figure 3This is a schematic diagram of a battery cell without solder ribbons provided in this embodiment. For example, the edge region on the surface of the battery cell 1 can be a region formed by extending 1 mm inward from both ends of the surface of the battery cell 1 along the extension direction of the solder ribbon 40, or it can be a region formed by extending 2 mm inward from both ends of the surface of the battery cell 1 along the extension direction of the solder ribbon 40, or it can be a region formed by extending inward at other distances from both ends of the extension direction of the solder ribbon 40. The specific settings can be made by the operator according to the fixing effect on both ends of the solder ribbon 40. In addition, in this embodiment, while ensuring the stability of the edge fixing of the solder ribbon 40, the region on the surface of the battery cell 1 where the edge bearing film 20 is provided can also be set as a region formed by extending inward at a first preset distance from the edge of the battery cell 1 and a second preset distance. The first preset distance and the second preset distance can be set according to the fixing effect on both ends of the solder ribbon 40, that is, the width of the edge bearing film 20 on the surface of the battery cell 1 along the extension direction of the solder ribbon 40 can be set according to the fixing effect. Accordingly, in this embodiment, the area where the low-temperature welding pad 30 is located can be determined in relation to the area where the edge bearing film 20 is set.

[0045] This embodiment does not limit the specific shape of the edge support film 20, as long as it can further fix both ends of the solder ribbon 40 when it is laid. Correspondingly, this embodiment does not limit the specific shape of the printed low-temperature soldering pad 30, which can be rectangular or other shapes. In this embodiment, the edge support film 20 can be selected from EVA (ethylene-vinyl acetate copolymer) film, POE film (POE film is a polyolefin elastomer film), EPE film (EPE film is a polyethylene foam film), PVB (polyvinyl butyral) film, etc. It should be further noted that in this embodiment, the solder ribbon 40 can be firmly connected to the low-temperature soldering pad 30 and the edge support film 20 by preheating, and the solder ribbon 40 can be connected to the fine grid 11 on the surface of the cell 1. The solder ribbon 40 can also be further fixed during the lamination process after the photovoltaic module is formed. It should be further noted that, in this embodiment, the fixed carrier film 50 can refer to the carrier film disposed on the outside of the solder ribbon 40 in a conventional battery string for fixing the solder ribbon 40. For example, it can be a fixed carrier film that is laid all over the outside of the solder ribbon 40 in conventional technology. In this embodiment, the solder ribbon 40 can be a low-temperature solder ribbon, which can be made of tin-lead-bismuth system material, wherein the bismuth content can be between 10% and 60%, and the melting point of the solder ribbon 40 is between 90 degrees Celsius and 130 degrees Celsius.

[0046] Furthermore, in order to ensure that the applied edge carrier film 20 and the printed low-temperature welding pad 30 can firmly connect the welding strip 40 to the surface of the battery cell, the thickness of the edge carrier film 20 can be set to 75 micrometers to 100 micrometers.

[0047] The low-temperature soldering pad 30 can be configured to use low-temperature solder paste, the thickness of which can be set to be 20 to 50 micrometers thicker than the edge carrier film 20.

[0048] It should be noted that in this embodiment, the thickness of the carrier film is set to 75 micrometers to 100 micrometers to ensure a stable connection between the edge carrier film 20 and the solder ribbon 40. Furthermore, to prevent the edge carrier film 20 from obstructing sufficient contact between the solder ribbon 40 and the low-temperature solder paste during solder ribbon application, thus avoiding poor contact, the thickness of the low-temperature solder paste is set to be greater than the thickness of the edge carrier film 20 to ensure close contact between the solder ribbon 40 and the low-temperature solder paste. Specifically, the thickness of the low-temperature solder paste is set to be 20 to 50 micrometers greater than the thickness of the edge carrier film 20 to ensure the stability of the pre-fixed connection between the low-temperature solder paste and the solder ribbon 40. Further, it should be noted that in this embodiment, the thickness of the low-temperature solder paste can be set to be 50 micrometers greater than the thickness of the edge carrier film 20 to ensure a stable connection with the solder ribbon even when the solder paste collapses in the thickness direction. It should be further noted that the low-temperature solder paste in this embodiment can be set as a tin-lead-bismuth system solder paste, wherein the bismuth content can be set to 10% to 60%, the melting temperature is 130 degrees Celsius to 150 degrees Celsius, the length along the extension direction of the fine gate 11 can be set to 1 mm, and the width along the preset direction can be set to 0.1 mm.

[0049] Furthermore, in order to reduce the material cost of the fixed bearing membrane 50, reference can be made to... Figure 4 , Figure 4 This is a schematic diagram of the structure of a battery cell in another battery string provided by an embodiment of the present invention. The aforementioned fixed support film 50 can be configured as a strip-shaped fixed support film.

[0050] It should be noted that in this embodiment, the fixing carrier film 50 is configured as a strip-shaped fixing carrier film, and multiple strip-shaped fixing carrier films are provided on the side of the solder ribbon 40 facing away from the battery cell 1. These multiple strip-shaped fixing carrier films are spaced apart on the side of the solder ribbon 40 facing away from the battery cell 1, and are connected to the battery cell 1 at the gaps between the solder ribbons 40 during heat fixing to fix the solder ribbon 40. This embodiment does not limit the specific way in which the multiple strip-shaped fixing carrier films are spaced apart, as long as it can firmly fix the solder ribbon 40 to the surface of the battery cell 1.

[0051] Furthermore, in order to balance the material cost of the strip-shaped fixed carrier film and the fixing effect on the welding strip 40, the laying direction of the strip-shaped fixed carrier film can be set to be perpendicular to the extension direction of the welding strip 40.

[0052] It should be noted that in this embodiment, the laying direction of the strip-shaped fixing support film is set perpendicular to the extension direction of the welding ribbon 40. This ensures the fixing effect of the strip-shaped fixing support film on the welding ribbon 40 while reducing the material usage of the strip-shaped fixing support film. Furthermore, in this embodiment, multiple strip-shaped fixing support films laid perpendicular to the extension direction of the welding ribbon 40 can be evenly spaced along the extension direction of the welding ribbon 40, or they can be set according to the fixing effect. For example, multiple strip-shaped fixing support films can be spaced smaller closer to the two edges along the extension direction of the welding ribbon 40 to further improve the fixing effect on both ends of the welding ribbon 40 and prevent the ends of the welding ribbon 40 from detaching. For details, please refer to [reference needed]. Figure 5 , Figure 5 This is a schematic diagram of the structure of a battery cell in another battery string provided in an embodiment of the present invention.

[0053] The battery string provided in this embodiment of the invention includes a plurality of battery cells 1 and solder strips 40 connecting adjacent battery cells 1. Each battery cell 1 has a central region and edge regions located on both sides of the central region along the extending direction of the solder strips 40. The surface of the battery cell has fine grids. The battery string also includes an edge support film 20 and a low-temperature welding pad 30 disposed in the edge regions. The edge support film 20 and the low-temperature welding pad 30 are used to pre-fix the solder strips 40 to the surface of the battery cells 1. By disposing of the edge support film 20 and the low-temperature welding pad 30 in the edge regions located on both sides of the central region of the battery cells 1 along the extending direction of the solder strips 40, and by using the edge support film 20 and the low-temperature welding pad 30 to pre-fix both ends of the solder strips 40, the contact yield of the solder strips 40 edges can be improved. Furthermore, by setting the thickness of the edge carrier film 20 to 75 micrometers to 100 micrometers, this embodiment of the invention can ensure a stable connection between the edge carrier film 20 and the solder ribbon 40. Correspondingly, by setting the thickness of the low-temperature solder paste to be 20 micrometers to 50 micrometers greater than the thickness of the edge carrier film 20, this embodiment of the invention can ensure the stability of the pre-fixed connection between the low-temperature solder paste and the solder ribbon, and prevent the edge carrier film 20 from affecting the connection between the solder ribbon 40 and the low-temperature solder paste. By setting the fixing carrier film 50 as a strip-shaped fixing carrier film, and providing multiple strip-shaped fixing carrier films on the side of the solder ribbon 40 facing away from the battery cell 1, this embodiment of the invention can reduce the material cost of the fixing carrier film 50 while ensuring the fixing effect. Setting the laying direction of the strip-shaped fixing carrier film to be perpendicular to the extension direction of the solder ribbon 40 further reduces the manufacturing cost.

[0054] Example 2:

[0055] The battery string provided in this embodiment of the invention differs from that in Embodiment 1 in that: the low-temperature welding pad is disposed on the fine grid in the edge region.

[0056] In this embodiment, by placing the low-temperature solder pad on the fine grid in the edge region, the solder ribbon can be connected to the fine grid on the surface of the cell through the applied low-temperature solder paste, thereby ensuring the stability of the connection between the solder ribbon and the fine grid on the surface of the cell and avoiding the problem of poor contact between the solder ribbon and the fine grid.

[0057] Furthermore, in order to improve the stability of fixing the solder ribbon to the surface of the solar cell while further reducing the manufacturing cost and improving the fixing efficiency, the aforementioned low-temperature soldering pad can be set on the fine grid adjacent to the edge of the solar cell.

[0058] The edge support membrane is located on the outside of the low-temperature welding pad.

[0059] In this embodiment, the fine grid near the edge of the solar cell is the outermost fine grid at both ends of the surface of the solar cell 1 along the extension direction of the solder strip. It should be noted that setting the fine grid near the edge of the solar cell as the outermost fine grid on the surface of the solar cell 1 along the extension direction of the solder strip ensures that the low-temperature solder pads located at the fine grid near the edge of the solar cell improve the stability of the connection between the solder strip ends and the solar cell 1. Furthermore, since printing the low-temperature solder pads at the outermost fine grid contributes the most to improving the connection stability at both ends of the solder strip, this not only solves the problem of easy detachment at the ends of the solder strip but also further reduces manufacturing costs and avoids the need for large-area application of low-temperature solder pads. In addition, this embodiment further improves the effect of the edge carrier film on the connection stability of the solder strip ends by providing an edge carrier film on the side of the fine grid near the edge of the solar cell closer to the edge of the solar cell. Moreover, since the edge carrier film only needs to be provided on the outer side of the fine grid, large-area application is not required, reducing material costs.

[0060] Furthermore, in order to ensure the preparation efficiency of the aforementioned edge support film, the edge support film can be configured as a strip-shaped edge support film corresponding to the edge of the battery cell.

[0061] It should be noted that in this embodiment, the edge carrier film can be a carrier film laid along the edge extension direction of the battery cell, that is, forming a strip-shaped edge carrier film disposed between the edge of the battery cell and the aforementioned edge grid. This eliminates the need for a separate edge carrier film for each solder ribbon connection area; the strip-shaped edge carrier film can be directly applied, improving the laying efficiency of the edge carrier film. Furthermore, if the process allows, setting the edge carrier film to be separately installed in designated areas corresponding to the solder ribbon placement areas can further reduce the material usage of the edge carrier film, but this further increases the manufacturing difficulty.

[0062] The battery string provided in this embodiment of the invention, by placing a low-temperature solder pad on the fine grid in the edge region, can connect the solder ribbon to the fine grid on the surface of the battery cell through the applied low-temperature solder paste, thereby improving the stability of the connection between the solder ribbon and the fine grid and avoiding contact problems. Furthermore, by setting the fine grid adjacent to the edge of the battery cell as the outermost fine grid along the extension direction of the solder ribbon on the surface of the battery cell, and placing the edge carrier film on the outer side of the fine grid adjacent to the edge of the battery cell, the stability of fixing the two ends of the solder ribbon is improved, while further reducing the manufacturing cost; by setting the edge carrier film as a strip-shaped edge carrier film corresponding to the edge of the battery cell, the application efficiency of the edge carrier film is improved.

[0063] Example 3:

[0064] Please refer to the details. Figure 6 , Figure 6 This is a schematic diagram of another battery string structure provided in an embodiment of the present invention. The battery string provided in this embodiment differs from that in Embodiment 1 in that: both sides of the edge region are provided with an edge bearing film 20 and a low-temperature welding pad 30; or,

[0065] One edge region has an edge support film 20 and a low-temperature welding pad 30 on its front side, and the other edge region has an edge support film 20 and a low-temperature welding pad 30 on its back side.

[0066] It should be noted that in this embodiment, the edge bearing film 20 and the low-temperature welding pad 30 can be correspondingly provided on the edge areas of both the front and back surfaces of each battery cell 1. Furthermore, it should be noted that in the battery string, the front side of one battery cell 1 is connected to the back side of another battery cell 1 by a welding ribbon 40. The welding ribbon 40 connecting the two battery cells 1 will bend between the two battery cells 1. The bending area is greatly affected by stress and is prone to delamination. Therefore, the welding ribbon 40 is prone to desoldering in the adjacent edge areas between two adjacent battery cells 1. Therefore, in order to improve the stability of the connection between the welding ribbon 40 and the battery cell 1 and reduce the manufacturing cost, the edge bearing film 20 and the low-temperature welding pad 30 can be provided only in the edge areas of adjacent battery cells 1 connected to the welding ribbon 40 for reinforcement. That is, the edge bearing film 20 and the low-temperature welding pad 30 are provided on the front side of one edge area and the edge bearing film 20 and the low-temperature welding pad 30 are provided on the back side of the other edge area. Furthermore, it should be noted that for the battery cell 1 located at the edge of the battery string, the aforementioned edge support film 20 and low-temperature welding pad 30 only need to be provided on the side of the edge region near the adjacent battery cell 1 that contacts the solder strip 40 connecting the two adjacent battery cells 1. It should also be noted that in this embodiment, the fixing support film 50 is a front support film provided on one side of the corresponding battery cell 1. It can refer to the conventional full-surface support film provided on the outside of the solder strip for fixing the solder strip, which is usually provided in the middle region of the aforementioned battery cell.

[0067] The battery string provided in this embodiment of the invention can maximize the stability of the connection between the solder ribbon 40 and the battery cell 1 by providing an edge bearing film 20 and a low-temperature welding pad 30 on both sides of the edge region of the battery cell 1. By providing an edge bearing film 20 and a low-temperature welding pad 30 on the front side of one edge region of the battery cell 1 and an edge bearing film 20 and a low-temperature welding pad 30 on the back side of the other edge region, the area with the highest risk of desoldering can be reinforced while ensuring the manufacturing cost, thereby improving the stability of the connection between the solder ribbon 40 and the battery cell 1.

[0068] The battery string provided by the present invention specifically includes a plurality of battery cells and solder strips connecting adjacent battery cells. Each battery cell has a central region and edge regions located on both sides of the central region along the extension direction of the solder strips. The surface of the battery cell has a fine grid. The battery string also includes an edge carrier film and a low-temperature welding pad disposed in the edge regions. The edge carrier film and the low-temperature welding pad are used to pre-fix the solder strips to the surface of the battery cells. The low-temperature welding pad is disposed on the fine grid in the edge regions. The edge carrier film and the low-temperature welding pad are disposed on both sides of the edge regions. Alternatively, the front side of one edge region is provided with an edge carrier film and the low-temperature welding pad is provided on the back side of the other edge region.

[0069] A fixed carrier film is applied to the solder ribbon to pre-fix the solder ribbon to the surface of the cell.

[0070] The low-temperature welding pad is set on the fine grid adjacent to the edge of the solar cell; the edge support film is located on the outside of the low-temperature welding pad; the edge support film is a strip-shaped edge support film set corresponding to the edge of the solar cell;

[0071] The thickness of the edge carrier film is 75 micrometers to 100 micrometers; the low-temperature solder pad is a low-temperature solder paste, which is 20 micrometers to 50 micrometers thicker than the edge carrier film.

[0072] The fixed support membrane is a strip-shaped fixed support membrane; the laying direction of the strip-shaped fixed support membrane is perpendicular to the extension direction of the welding strip.

[0073] The following describes the battery string preparation method provided in the embodiments of the present invention. The battery string preparation method described below can be referred to in correspondence with the battery string described above.

[0074] Please refer to Figure 6 , Figure 6 This is a flowchart illustrating a method for preparing a battery string according to an embodiment of the present invention. It may include the following steps:

[0075] S101: Low-temperature welding pads are provided at the edge of the solar cell.

[0076] S102: Lay an edge support film in the edge area of ​​the solar cell.

[0077] In this embodiment, when preparing the aforementioned edge support film and low-temperature welding pad, no welding strip is laid on the surface of the battery cell. However, the edge support film and low-temperature welding pad need to be set up to correspond to the welding strip to be laid later, so that after the welding strip is laid, the aforementioned edge support film and low-temperature welding pad can be used to fix the welding strip.

[0078] S103: Lay the solder ribbon on the surface of the cell and align it with the position of the edge support film and the low-temperature welding pad.

[0079] In this embodiment, the solder strip is provided corresponding to the aforementioned edge support film and low-temperature welding pad, so that the solder strip can be fixed using the edge support film and low-temperature welding pad.

[0080] It should be noted that, in this embodiment, after the solder ribbon is laid, it can be locally heated at a temperature of 100°C to 130°C to initially fix the solder ribbon to the low-temperature welding pad and the edge carrier film. Furthermore, in this embodiment, after the carrier film is laid, it can be heated again at a temperature of 100°C to 130°C to make the carrier film adhere tightly to the solar cell at the gaps between the solder ribbons, thereby making the solder ribbon adhere tightly to the fine grid on the surface of the solar cell. After lamination to form a photovoltaic module, a lamination process is performed. Alternatively, the solder ribbon can be heated and fixed once after the carrier film is laid, and the photovoltaic module is formed after the solder ribbon is pre-fixed and then laminated.

[0081] S104: Place the fixed carrier film onto the battery cell and cover it with the solder ribbon.

[0082] S105: Heating fixes the solder ribbon to the surface of the cell and electrically connects the solder ribbon to the grid.

[0083] It should be noted that, in this embodiment, when preparing the above-mentioned battery string, the solder strip can be prepared on the front side of the battery cell using the above method. On the back side of the battery cell located at an adjacent position, a fixed carrier film can be prepared first, a solder strip can be set at the corresponding position on the surface of the fixed carrier film, and an edge carrier film can be set at the corresponding position on the solder strip. Then, a battery cell with a low-temperature welding pad set at the corresponding position on the back side can be set. The battery string preparation is completed by repeating the process.

[0084] The battery string fabrication method provided in this invention includes setting a low-temperature welding pad in the edge region of the battery cell, applying an edge carrier film in the edge region of the battery cell, applying a solder ribbon on the surface of the battery cell corresponding to the positions of the edge carrier film and the low-temperature welding pad, placing a fixing carrier film on the battery cell and covering the solder ribbon, heating to fix the solder ribbon to the surface of the battery cell, and electrically connecting the solder ribbon to the grid. This invention utilizes the aforementioned edge carrier film and low-temperature welding pad to pre-fix both ends of the solder ribbon, solving the problem of unstable connection between the ends of the solder ribbon and the battery cell in existing schemes that apply a carrier film to the outside of the solder ribbon, thereby improving the contact yield of the module and avoiding open circuits.

[0085] The photovoltaic module provided in the embodiments of the present invention is described below. The photovoltaic module described below can be referred to in correspondence with the battery string described above.

[0086] Please refer to the details. Figure 7 , Figure 7 A schematic diagram of a photovoltaic module provided in an embodiment of the present invention may include:

[0087] The first encapsulation film 70, the second encapsulation film 80, the front plate 60, the back plate 90, and the battery string as described above;

[0088] The first encapsulation film 70 and the second encapsulation film 80 are respectively disposed on both sides of the battery string, and the front plate 60 and the back plate 90 are respectively disposed on the outer sides of the first encapsulation film 70 and the second encapsulation film 80.

[0089] In this embodiment, the battery layers forming the photovoltaic module typically consist of multiple sets of battery strings. These sets of battery strings are connected to form a solar panel, and the photovoltaic module is led out using wires. After the layers of the module are stacked, a lamination process is performed. During this process, the first encapsulating film 70 and the second encapsulating film 80 in the photovoltaic module can form an integrated structure with the fixing and bearing film 50 on the surface of the battery strings, improving the fixing effect.

[0090] The photovoltaic module provided in this embodiment of the invention includes a first encapsulating film 70, a second encapsulating film 80, a front panel 60, a back panel 90, and a battery string as described above. The first encapsulating film 70 and the second encapsulating film 80 are respectively disposed on both sides of the battery string, and the front panel 60 and the back panel 90 are respectively disposed on the outer sides of the first encapsulating film 70 and the second encapsulating film 80. The first encapsulating film 70 and the second encapsulating film 80 are both laminated with the fixed carrier film 50 in the battery string to form an integral structure. In this embodiment of the invention, the photovoltaic module is formed using the battery string. By setting an edge carrier film 20 and a low-temperature welding pad 30 on the edge regions of the battery cell 1 along the extension direction of the solder ribbon 40 in the middle region of the battery cell 1, and using the edge carrier film 20 and the low-temperature welding pad 30 to pre-fix the two ends of the solder ribbon 40, the contact yield of the edge of the solder ribbon 40 can be improved. At the same time, by setting the first encapsulating film 70 and the second encapsulating film 80 to be integrally formed with the fixed carrier film 50 on the surface of the battery string through lamination, the fixing effect of the solder ribbon 40 is improved.

[0091] The photovoltaic module preparation method provided in the embodiments of the present invention is described below. The photovoltaic module preparation method described below can be referred to in correspondence with the photovoltaic module described above.

[0092] Please refer to Figure 8 , Figure 8 A flowchart of a photovoltaic module manufacturing method provided in this embodiment of the invention may include the following steps:

[0093] Step S21: Provide the battery string as described above.

[0094] In this embodiment, the battery string includes a plurality of battery cells and solder strips connecting adjacent battery cells. The battery cells have a central region and edge regions located on both sides of the central region along the extension direction of the solder strips. The battery string also includes at least an edge support film and a low-temperature welding pad disposed in the edge regions. The edge support film and the low-temperature welding pad are used to pre-fix the solder strips to the surface of the battery cells. The battery string also includes a fixing support film, which covers the solder strips to pre-fix the solder strips to the surface of the battery cells.

[0095] Step S22: Stack the front panel, the first encapsulating film, the battery string, the second encapsulating film, and the back panel sequentially along the stacking direction to form the component to be laminated.

[0096] Step S23: Perform lamination on the module to be laminated, and make the first encapsulating film and the second encapsulating film form an integral structure with the fixed carrier film in the battery string to obtain the photovoltaic module.

[0097] The photovoltaic module manufacturing method provided in this invention includes providing a battery string as described above, sequentially stacking a front panel, a first encapsulating film, a battery string, a second encapsulating film, and a back panel along the stacking direction to form a module to be laminated, performing a lamination process on the module to be laminated, and ensuring that both the first and second encapsulating films form an integral structure with the fixed carrier film in the battery string to obtain a photovoltaic module. This invention utilizes the aforementioned battery string to manufacture photovoltaic modules. By setting edge carrier films and low-temperature welding pads on the edge regions of the battery cells along the extension direction of the solder strip in the middle region of the battery cells, and using these edge carrier films and low-temperature welding pads to pre-fix the two ends of the solder strip, the contact yield of the solder strip edges can be improved. Simultaneously, by setting both the first and second encapsulating films as an integral structure with the fixed carrier film on the surface of the battery string through lamination, the fixing effect of the solder strip is improved.

[0098] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0099] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0100] Finally, it should be noted that in this document, relationships such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0101] The present invention has provided a detailed description of a battery string, a method for preparing the battery string, and a photovoltaic module. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A battery string comprising a plurality of battery cells and solder strips connecting adjacent battery cells, wherein each battery cell has a central region and edge regions located on both sides of the central region along the extending direction of the solder strips, and the surface of each battery cell has fine grids, characterized in that: The battery string also includes an edge support film and a low-temperature welding pad disposed in the edge region, the edge support film and the low-temperature welding pad being used to pre-fix the welding strip to the surface of the battery cell; A fixed carrier film is used to cover the solder ribbon to pre-fix the solder ribbon to the surface of the battery cell.

2. The battery string according to claim 1, characterized in that, The low-temperature welding pad is disposed on the fine grid in the edge region.

3. The battery string according to claim 2, characterized in that, The low-temperature welding pad is disposed on the fine grid adjacent to the edge of the battery cell; The edge-bearing membrane is located on the outside of the low-temperature welding pad.

4. The battery string according to claim 3, characterized in that, The edge support film is a strip-shaped edge support film that is disposed corresponding to the edge of the battery cell.

5. The battery string according to claim 1, characterized in that, Both sides of the edge region are provided with the edge bearing film and the low-temperature welding pad; or... One edge region has the edge support film and the low-temperature welding pad disposed on its front side, and the other edge region has the edge support film and the low-temperature welding pad disposed on its back side.

6. The battery string according to claim 1, characterized in that, The thickness of the edge-bearing membrane is 75 micrometers to 100 micrometers; The low-temperature soldering pad is a low-temperature solder paste, and the thickness of the low-temperature solder paste is 20 to 50 micrometers thicker than the thickness of the edge carrier film.

7. The battery string according to claim 1, characterized in that, The fixed bearing membrane is a strip-shaped fixed bearing membrane.

8. The battery string according to claim 7, characterized in that, The strip-shaped fixed bearing membrane is laid in a direction perpendicular to the extension direction of the welding strip.

9. A method for preparing a battery string, characterized in that, For preparing the battery string as described in any one of claims 1 to 8, comprising: Low-temperature welding pads are installed at the edge areas of the solar cells; An edge-supporting film is applied to the edge area of ​​the battery cell; The solder strip is laid on the surface of the battery cell and corresponds to the position of the edge support film and the low-temperature welding pad; The fixing carrier film is placed on the battery cell and covered with the solder strip; Heating causes the solder ribbon to be fixed to the surface of the battery cell and electrically connected to the grid.

10. A photovoltaic module, characterized in that, include: The first encapsulating film, the second encapsulating film, the front plate, the back plate, and the battery string as described in any one of claims 1 to 8; The first encapsulating film and the second encapsulating film are respectively disposed on both sides of the battery string, and the front plate and the back plate are respectively disposed on the outer sides of the first encapsulating film and the second encapsulating film.

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