Battery module structure

Abstract

The utility model discloses a battery module structure, which comprises a plurality of battery pieces and conductive connecting pieces for connecting two adjacent battery pieces, grid lines are arranged on the battery pieces, connecting strips electrically connected with the grid lines are further arranged on the battery pieces, and the connecting strips abut against the conductive connecting pieces. As the connecting strip is directly abutted against the conductive connecting piece, and no other connecting structure or welding layer is arranged between the connecting strip and the conductive connecting piece, the contact resistance of the metal grid line and the conductive connecting piece is reduced, the photoelectric conversion efficiency of the battery piece is improved, and the power generation production cost of the whole battery module is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic cells, in particular to a battery module structure. Background Art

[0002] At present, the solar industry produces a large number of crystalline silicon solar cells, and the various metal grid lines (electrodes) on their surfaces are made by screen printing silver paste and sintering. However, the electrode grid lines produced by this method have a small aspect ratio (after sintering, the average width is 30-50μm and the height is about 10-15μm), resulting in a large shading area for the cell (the front shading area ranges from 4-5%). In addition, the price of silver paste is expensive (about 4,500-7,500 yuan per kilogram of silver paste), so how to improve efficiency and reduce production costs is a top priority for all cell manufacturers.

[0003] One of the most popular and feasible directions is to replace the long-standing solar cell main grid with 0BB (Busbar) technology. Then, because of the poor conductivity of silver paste, the number of BBs of photovoltaic cells has developed from the original 3BB to 20BB, and more cell slicing processes must be performed. Although it can effectively improve the conversion efficiency output and reduce the consumption of silver paste, it is still impossible to completely remove the silver, and the laser slicing process has also been added, which has increased the process and cost of the cell. In addition, in the traditional process of module packaging in the past, because the string welding grid line has become thinner, it also brings problems to the alignment of the module packaging. That is, the alignment during welding cannot ensure that the string welding rod can completely overlap the grid line on the cell, resulting in a cold weld, which will increase the contact resistance. Or when the cell group is in the process of string welding, the cell is hidden. The power generation and reliability of the module are reduced. Utility Model Content

[0004] In order to overcome the above disadvantages, the purpose of the present invention is to provide a battery module structure.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is: a battery module structure, including multiple battery cells and conductive connecting parts connecting two adjacent battery cells, the battery cells are provided with grid lines, and the battery cells are also provided with connecting strips electrically connected to the grid lines, the connecting strips and the conductive connecting parts are directly abutted, and no other connecting layers or welding layers are provided.

[0006] Further, the width of the connecting strip is in the range of 100μm to 500μm, the thickness is in the range of 5μm to 80μm, the conductive connector is overlapped with the connecting strip, and the width of the overlap is in the range of 0.5mm to 2.5mm. Exemplarily, the width of the connecting strip is 100μm, 200μm, 300μm, 400μm, 500μm, the thickness is 5μm, 10μm, 20μm, 40μm, 60μm, 80μm, and the width of the overlap is 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm.

[0007] Furthermore, the conductive connecting member and the connecting strip are made of the same metal or metal alloy, which can achieve lower contact resistance.

[0008] Furthermore, the conductive connecting member and the connecting strip are made of metal copper or copper alloy.

[0009] Furthermore, an insulating adhesive layer is provided between the battery cell and the conductive connector, the insulating adhesive layer is provided on one side or both sides of the connecting strip, and the thickness of the insulating adhesive layer ranges from 5 μm to 100 μm. Exemplarily, the thickness of the insulating adhesive layer is 5 μm, 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, or 100 μm.

[0010] Furthermore, the connecting strip (14) is in a straight line or an "S" shape, and the insulating adhesive layer (15) is in a straight line or a dot-shaped structure, and is arranged on one side or both sides of the connecting strip (14).

[0011] Furthermore, an insulating layer is provided between the conductive connecting member and the side edge of the battery cell, or a gap is left between the conductive connecting member and the side edge of the battery cell.

[0012] Furthermore, the conductive connector includes a conductive plate, and the two ends of the conductive plate are respectively provided with a front connecting plate and a back connecting plate integrally formed therewith, the conductive plate is located between the side edges of two adjacent battery cells, the front connecting plate is affixed to the connecting strip on the front side of one of the battery cells, and the back connecting plate is affixed to the connecting strip on the back side of the other battery cell.

[0013] Furthermore, a surface of the front connecting plate away from the battery cell is flat or circular.

[0014] Further, the thickness of the conductive connector is in the range of 0.1 mm to 0.5 mm, and the length is in the range of 150 mm to 250 mm. Exemplarily, the thickness of the conductive connector is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, and the length is 150 mm, 170 mm, 190 mm, 210 mm, 230 mm, 250 mm.

[0015] The beneficial effects of the utility model are:

[0016] 1) Since the connecting strip and the conductive connector are directly in contact, no other connecting structure or welding layer is set between the connecting strip and the conductive connector, which reduces the contact resistance between the metal grid line and the conductive connector, improves the photoelectric conversion efficiency of the battery cell, and reduces the power generation production cost of the overall battery module.

[0017] 2) The battery cell string group is produced by replacing the past practice of connecting two battery cells with a string welding rod with a conductive connector. Since the string welding rod is no longer used for module packaging, the bonding strength of the entire module is improved.

[0018] 3) By setting the insulating adhesive layer, there is no need to set a welding layer between the conductive connector and the connecting bar to fix their position. On the one hand, the contact resistance between the connecting bar and the conductive connector is reduced, and on the other hand, the stability of the battery module structure is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and the description thereof are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. 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.

[0021] Figure 1 This is a schematic diagram of the battery module structure connection of an embodiment of the utility model;

[0022] Figure 2 This is a schematic diagram of the battery module structure connection of another embodiment of the utility model;

[0023] Figure 3 A schematic diagram of the connection between the grid lines and the connecting bars according to an embodiment of the utility model;

[0024] Figure 4 A schematic diagram of connection between grid lines and connecting bars according to another embodiment of the utility model;

[0025] Figure 5 It is a three-dimensional diagram of a conductive connecting member according to an embodiment of the present utility model.

[0026] In the figure: 1. Battery cell; 11. Front; 12. Back; 13. Grid line; 14. Connecting bar; 15. Insulating adhesive layer; 2. Conductive connector; 21. Front connecting plate; 22. Back connecting plate; 23. Conductive plate; 3. Insulating layer. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0028] See attached Figure 1 and attached Figure 2 As shown, a battery module structure in this embodiment includes multiple battery cells 1, and two adjacent battery cells 1 are connected by a conductive connector 2. Specifically, the battery cell 1 includes a battery front 11 and a battery back 12. One end of the conductive connector 2 is connected to the front side 11 of the battery cell 1, and the other end is connected to the back side 12 of another adjacent battery cell 1, so that the multiple battery cells 1 are connected in series to form a battery module.

[0029] See attached Figure 1-4As shown, in some embodiments, the front 11 and the back 12 of the battery cell 1 are both provided with a plurality of grid lines 13, and the plurality of grid lines 13 are arranged side by side and equidistantly on the front 11 and the back 12 of the battery cell 1. Connecting bars 14 are arranged at both ends of the grid lines 13 near the edge of the battery cell 1, and the connecting bars 14 are connected to the ends of the grid lines 13 to converge the current on the plurality of grid lines 13. The connecting bar 14 is directly abutted against the conductive connector 2, and no other connecting structure or welding layer is arranged between the connecting bar 14 and the conductive connector 2, so as to reduce the contact resistance between the metal grid lines and the conductive connector 2, and finally improve the photoelectric conversion efficiency of the battery cell, and reduce the power generation production cost of the overall battery module. The width of the connecting bar 14 ranges from 100μm to 500μm, and the thickness ranges from 5μm to 80μm. Specifically, one end of the conductive connector 2 is overlapped with the connecting bar 14 of the front 11 of the battery cell 1, and the width of the contact overlap between the conductive connector 2 and the connecting bar 14 ranges from 0.5mm to 2.5mm. The other end is in contact with the connecting bar 14 on the back side 12 of another battery cell 1, and multiple battery cells 1 are connected in series through the conductive connector 2. The battery cell 1 string group is produced by replacing the method of connecting two battery cells 1 with a string welding rod that has been used for many years with the conductive connector 2. Since the string welding rod is no longer used for module packaging, the bonding strength of the entire module is improved. And because the grid line 13 and the connecting bar 14 on the battery cell 1 are directly connected to the conductive connector 2, and the conductive connector 2, the grid line 13 and the connecting bar 14 are made of the same metal material, compared with the contact using the previous string solder, the direct connection between the conductive connector 2 and the connecting bar 14 can obtain a lower contact resistance.

[0030] In some embodiments, the material of the grid line 13 is metallic copper, and the metallic copper grid line 13 is disposed on the cell 1 by electroplating. This has been recognized by many photovoltaic experts and many cell factories and has actually obtained measurement values. The specific data is that the average Rs electrical property measurement value (Rs, i.e., series resistance) of the cell 1 with copper metal grid lines is 0.0015 or lower. The average Rs electrical property measurement value (Rs, i.e., series resistance) of the cell 1 prepared with silver paste metal grid lines is 0.0030 or higher. This directly leads to a decrease in the fill factor (FF) (ranging from 1% to 2.5%). Ultimately, the photoelectric conversion efficiency of the cell 1 will also decrease. Therefore, the present application replaces the silver paste with copper metal on the metal grid line 13 of the cell 1, whether it is a high-temperature or low-temperature type of silver paste, to improve the photoelectric conversion efficiency of the cell 1.

[0031] See attached Figure 3 and attached Figure 4As shown, in some embodiments, an insulating adhesive layer 15 is provided between the battery cell 1 and the conductive connector 2, and the battery cell 1 and the conductive connector 2 are fixedly connected by the insulating adhesive layer 15 to prevent the conductive connector 2 from shifting. The thickness of the insulating adhesive layer 15 ranges from 5μm to 100μm. The insulating adhesive layer 15 is provided on one side or both sides of the connecting strip 14, and is arranged side by side with the connecting strip 14 on the surface of the battery cell 1. During the preparation process, an adhesive is coated on the side of the copper connecting strip 14 on the battery cell 1, and then the battery cell 1 and the conductive connector 2 coated with the adhesive are aligned, pressurized and heated to prepare a battery cell 1 string group. The specific operating conditions are a temperature range of 70℃ to 150℃, 0.5Kg / cm 2 ~3.0Kg / cm 2 The pressure range is 5 seconds to 60 seconds of heating and pressurizing the bonding time range. When applying the adhesive, a gap is left between the insulating adhesive and the connecting strip 14 to prevent the formation of an insulating adhesive layer 15 between the conductive connector 2 and the connecting strip 14 during the pressurizing and heating process.

[0032] In some embodiments, see Appendix Figure 3 As shown, the connecting bar 14 is a straight line and is arranged perpendicular to the gate line 13. The insulating glue layer 15 is a straight line and is arranged parallel to one side or both sides of the connecting bar 14. Figure 4 As shown, the connecting strip 14 may also be in an "S" shape, and the insulating adhesive layer 15 is a dot-shaped structure, which is arranged at the groove of the "S"-shaped connecting strip 14. By setting the connecting strip 14 in an "S" shape, the stress of the connecting strip 14 can be reduced.

[0033] In some embodiments, see Appendix Figure 5 As shown, the conductive connector 2 is an integrally formed conductive metal, which is formed into a stepped conductive connector 2 with an upper cover and a lower support by extrusion. The conductive connector 2 is made of copper metal or a copper alloy component, and its thickness ranges from 0.1mm to 0.5mm, and its length ranges from 150mm to 250mm. Specifically, the conductive connector 2 includes a conductive plate 23, and the two ends of the conductive plate 23 are respectively provided with a front connecting plate 21 and a back connecting plate 22 integrally formed therewith, and the conductive plate 23 is located between the sides of the two adjacent battery cells 1. The front connecting plate 21 is attached to the connecting strip 14 of the front side 11 of one of the battery cells 1; the back connecting plate 22 is attached to the connecting strip 14 of the back side 12 of another of the battery cells 1. A current path is formed by the connecting strip 14 located on the front side 11 of the battery cell 1 - the front connecting plate 21 - the conductive plate 23 - the back connecting plate 22 - the connecting strip 14 located on the back side 12 of another battery cell 1. Multiple groups of battery cells 1 are connected in series through the conductive connector 2, replacing the traditional string welding tape and solving the problem of string welding alignment offset.

[0034] In some embodiments, the side of the front connecting plate 21 away from the solar cell 1 is flat or circular, preferably circular, which can enhance the reflection of sunlight and increase more light.

[0035] See attached Figure 2 As shown, in some embodiments, an insulating layer 3 is provided between the conductive plate 23 and the side of the battery cell 1. If the edge of the battery cell 1 is not coated with the insulating layer 3 and the conductive connector 2 is not coated with the insulating layer 3, the two will be conductive after contact. By providing the insulating layer 3, the edge of the battery cell 1 and the conductive connector 2 are insulated, preventing the battery cell 1 from contacting the conductive connector 2 and causing conduction, resulting in failure of the battery module. Or refer to the attached Figure 1 As shown, a gap is left between the conductive plate 23 and the side of the battery cell 1 to prevent the edge of the battery cell 1 from being electrically connected to the conductive connector 2 .

[0036] The production process is:

[0037] S1 . Apply adhesive to the sides of the connecting strips 14 of the battery cell 1 .

[0038] S2, aligning and covering the conductive connecting member 2 on the battery cell coated with adhesive, so that the conductive sheet and the battery cell are connected and overlapped.

[0039] S3, 120℃, pressure 1.5Kg / cm 2 With a 10-second operation process, an insulating adhesive layer 15 is formed to connect the battery cells in series.

[0040] S4. Lamination preparation is performed on the completed battery cell assembly string. After the assembly string, packaging mold, back plate and glass are properly placed, the assembly lamination process is performed. The process operation conditions are a curing time of 25 minutes, a curing temperature of 180°C and a pressure of 1.0MPa.

[0041] The above implementation modes are only for illustrating the technical concept and features of the utility model, and their purpose is to allow people familiar with this technology to understand the content of the utility model and implement it. It cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A battery module structure, characterized in that: The invention comprises a plurality of battery cells (1) and a conductive connecting member (2) connecting two adjacent battery cells (1); a grid line (13) is provided on the battery cell (1); a connecting bar (14) is provided at the end of the grid line (13) near the edge of the battery cell (1); the connecting bar (14) and the end of the grid line (13) are electrically connected; the connecting bar (14) and the conductive connecting member (2) are in abutment with each other; and the conductive connecting member (2) and the connecting bar (14) are made of the same metal or metal alloy.

2. A battery module structure according to claim 1, characterized in that: The width of the connecting strip (14) is in the range of 100 μm to 500 μm, and the thickness is in the range of 5 μm to 80 μm. The conductive connecting element (2) and the connecting strip (14) are arranged to overlap, and the width of the overlapped portion is in the range of 0.5 mm to 2.5 mm.

3. A battery module structure according to any one of claims 1-2, characterized in that: The conductive connecting piece (2) and the connecting strip (14) are made of metal copper or copper alloy.

4. A battery module structure according to claim 1, characterized in that: An insulating adhesive layer (15) is provided between the battery cell (1) and the conductive connecting member (2); the insulating adhesive layer (15) is provided on one side or both sides of the connecting strip (14); and the thickness of the insulating adhesive layer (15) ranges from 5 μm to 100 μm.

5. A battery module structure according to claim 4, characterized in that: The connecting strip (14) is in a straight line or an "S" shape, and the insulating adhesive layer (15) is in a straight line or a dot-shaped structure, and is arranged on one side or both sides of the connecting strip (14).

6. A battery module structure according to claim 1, characterized in that: An insulating layer (3) is provided between the conductive connecting member (2) and the side edge of the battery cell (1), or a gap is left between the conductive connecting member (2) and the side edge of the battery cell (1).

7. A battery module structure according to claim 1, characterized in that: The conductive connecting member (2) comprises a conductive plate (23), and two ends of the conductive plate (23) are respectively provided with a front connecting plate (21) and a back connecting plate (22) integrally formed therewith, the conductive plate (23) being located between the side edges of two adjacent battery cells (1), the front connecting plate (21) being attached to a connecting strip (14) on the front side (11) of one battery cell (1), and the back connecting plate (22) being attached to a connecting strip (14) on the back side (12) of another battery cell (1).

8. A battery module structure according to claim 7, characterized in that: The surface of the front connecting plate (21) away from the battery cell (1) is flat or circular.

9. A battery module structure according to claim 1, characterized in that: The conductive connecting piece (2) has a thickness ranging from 0.1 mm to 0.5 mm and a length ranging from 150 mm to 250 mm.

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