Back contact battery strings, modules and photovoltaic systems

Abstract

This utility model relates to the field of silicon solar cells, specifically disclosing a back-contact cell string, module, and photovoltaic system. The back-contact cell string includes: multiple solar cells arranged along a first direction; multiple solder ribbons for electrically connecting adjacent solar cells; the solder ribbons arranged along a second direction on the solar cells, extending along the first direction and intersecting with the second direction; and fixing adhesive dots disposed on the solar cells to fix the solder ribbons to the solar cells. The width of the solder ribbons and the width of the fixing adhesive dots conform to the following relationship: 0.75 ≤ D / L < 6; where D is the width of the fixing adhesive dot and L is the width of the solder ribbon. The back-contact cell string of this utility model has the advantages of high welding yield and low microcrack rate, improving the overall yield and reliability of the back-contact cell module.

Description

Technical Field

[0001] This utility model relates to the field of silicon solar cells, and in particular to a back-contact cell string, module and photovoltaic system. Background Technology

[0002] During the module manufacturing process, solar cells need to be coated with adhesive first, then cut, arranged, and have auxiliary components (such as solder ribbons, busbars, backsheets, adhesive films, tempered glass, etc.) added. Finally, post-soldering is used to complete the circuit conduction. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a back contact battery string, battery module and photovoltaic system with high welding yield, low microcrack rate and high overall yield.

[0004] To address the aforementioned problems, this utility model discloses a back-contact battery string, comprising:

[0005] Multiple solar cells are arranged along a first direction;

[0006] Multiple solder strips for electrically connecting adjacent solar cells; the multiple solder strips are arranged on the solar cells along a second direction, the solder strips extending along a first direction, the first direction and the second direction being intersected; and

[0007] A fixing adhesive dot is disposed on the battery cell to fix the solder ribbon to the battery cell;

[0008] The width of the solder strip and the width of the fixing adhesive dot conform to the following relationship: 0.75≤D / L<6;

[0009] In the formula, D is the width of the fixed adhesive dot, and L is the width of the solder strip.

[0010] As an improvement to the above technical solution, the width of the welding strip is 0.4mm to 3mm; and / or

[0011] The width of the fixing adhesive dots is 0.75mm to 5mm.

[0012] As an improvement to the above technical solution, the width of the solder strip and the width of the fixing adhesive dot conform to the following relationship: 1≤D / L≤4;

[0013] In the formula, D is the width of the fixed adhesive dot, and L is the width of the solder strip.

[0014] As an improvement to the above technical solution, the solder strip extends beyond the coverage area of ​​the fixing adhesive dot in the first direction.

[0015] As an improvement to the above technical solution, the fixing adhesive dots are transparent adhesive dots or black adhesive dots.

[0016] As an improvement to the above technical solution, the fixing adhesive dots are fluorescent adhesive dots;

[0017] The width of the solder strip and the width of the fixing adhesive dot conform to the following relationship: D / L > 1;

[0018] In the formula, D is the width of the fixed adhesive dot, and L is the width of the solder strip.

[0019] As an improvement to the above technical solution, the battery cell is a gridless battery cell, and the battery cell has a first edge and a second edge in a first direction;

[0020] The battery cell has a first pad area and a second pad area on both sides in a first direction for forming pads. The first pad area is located near the first edge, and the second pad area is located near the second edge.

[0021] In a first direction, the fixing adhesive dots are disposed between the first edge and the first pad area; and / or

[0022] In the first direction, the fixing adhesive dots are located between the second edge and the second pad area.

[0023] As an improvement to the above technical solution, the battery cell has a first edge and a second edge in a first direction; the battery cell is provided with main grid lines arranged along a second direction;

[0024] The battery cell has a first pad area and a second pad area on both sides in a first direction for forming pads. The first pad area is located near the first edge, and the second pad area is located near the second edge.

[0025] In a first direction, the fixing adhesive dots are disposed between the first pad region and the second pad region; and / or

[0026] In a first direction, the fixing adhesive dots are disposed between the first edge and the first pad area; and / or

[0027] In the first direction, the fixing adhesive dots are located between the second edge and the second pad area.

[0028] As an improvement to the above technical solution, the pad includes a PAD point and an end line, the end line extends along a second direction, and there is an offset gap between the end line and the center line of the PAD point along the second direction.

[0029] The fixing adhesive dots are staggered from the end lines.

[0030] As an improvement to the above technical solution, the solder strip is connected to the PAD point, and the end line is exposed outside the solder strip.

[0031] Accordingly, this utility model also discloses a back contact battery assembly, which includes the aforementioned back contact battery string.

[0032] Accordingly, this utility model also discloses a photovoltaic system, which includes the aforementioned back contact battery assembly.

[0033] Implementing this utility model has the following beneficial effects:

[0034] One embodiment of this utility model discloses a back-contact battery string, which includes multiple battery cells, multiple solder ribbons, and multiple fixing adhesive dots. The multiple battery cells are arranged along a first direction, and the multiple solder ribbons are arranged along a second direction on the back surface of the battery cells, extending along the first direction. The multiple fixing adhesive dots are disposed on the back surface of the battery cells and are used to fix the solder ribbons to the back surface of the battery cells. Specifically, the width of the solder ribbon (i.e., its extension width in the second direction) and the width of the fixing adhesive dots (i.e., their extension width in the second direction) conform to the following relationship: 0.75 ≤ < D / L < 6; where D is the width of the fixing adhesive dot and L is the width of the solder ribbon. Based on the above technical solution, firstly, it solves the problem that the adhesive dots are difficult to effectively fix the solder ribbons due to too much or too little fixing adhesive, effectively preventing solder ribbon misalignment and reducing the probability of cold solder joints. Secondly, it prevents uneven distribution of adhesive after dispensing due to excessive fixing adhesive, reducing the microcrack rate during lamination and improving the yield rate. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of a back-contact solar cell string in one embodiment of this utility model;

[0036] Figure 2 This is a schematic diagram of the back structure of the battery cell in one embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the back contact battery assembly in one embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the back contact battery assembly in another embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the system composition of a photovoltaic system in one embodiment of this utility model. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0041] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0043] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0045] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0046] See Figure 1 , Figure 2 This embodiment discloses a back-contact battery string 10, which includes multiple battery cells 1, multiple solder ribbons 2, and multiple adhesive dots 3. The multiple battery cells 1 are arranged along a first direction, and the multiple solder ribbons 2 are arranged along a second direction on the back surface of the battery cells 1, extending along the first direction. The multiple adhesive dots 3 are disposed on the back surface of the battery cells 1 and are used to fix the solder ribbons 2 to the back surface of the battery cells 1. Specifically, the width of the solder ribbon 2 (i.e., its extension width in the second direction) and the width of the adhesive dots 3 (i.e., their extension width in the second direction) conform to the following relationship: 0.75 ≤ D / L < 6; where D is the width of the adhesive dots 3 and L is the width of the solder ribbon 2.

[0047] Based on the above technical solutions, firstly, by establishing a correspondence between the width of the fixing adhesive dots 3 and the width of the solder ribbon 2, the problem of insufficient or excessive fixing adhesive causing the fixing adhesive dots 3 to effectively fix the solder ribbon 2 is solved, effectively preventing the solder ribbon 2 from shifting and reducing the probability of cold solder joints. It should be noted that if the fixing adhesive dots 3 are too small, i.e., the amount of adhesive applied is too small, the solder ribbon 2 will not be firmly fixed and is prone to shifting during battery string transfer and lamination; if the fixing adhesive dots 3 are too large, i.e., the amount of adhesive applied is too large, it may not cure sufficiently before placing the solder ribbon 2, resulting in an unstable fixation of the solder ribbon 2 and a tendency to shift during battery string transfer and lamination. Secondly, by establishing a correspondence between the width of the fixing adhesive dots 3 and the width of the solder ribbon 2, uneven adhesive distribution after application due to excessive fixing adhesive is prevented, preventing microcracks during lamination and improving yield. It should be noted that when the amount of fixing adhesive is too large, it is unevenly dispersed on the surface of the battery cell 1, and the fixing adhesive dots 3 formed after surface drying have a large height difference in their cross-section. This will create stress concentration points during lamination, leading to microcracks.

[0048] The width of the solder strip 2 can be determined according to the size of the battery cell 1, the thickness of the grid lines on the connected battery cell 1, and its specific material. In some embodiments, the width of the solder strip 2 is 0.4mm to 3.5mm, exemplarily 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, or 3.2mm, but is not limited thereto. Preferably, it is 0.4mm to 3mm, 1mm to 2.5mm, or 0.8mm to 2mm, but is not limited thereto. It should be noted that when the solder strip 2 is too thin, it will result in high resistivity, high transmission loss, and reduced output power of the battery string; when the solder strip 2 is too wide, the welding thermal stress during lamination welding will be large, which can easily lead to poor soldering, over-soldering, and microcracks.

[0049] Specifically, the cross-section (the section along its width direction) of the welding strip 2 can be circular, square, or elliptical, but is not limited to these. Correspondingly, the width of the welding strip 2 is the diameter of the cross-section of the circular welding strip, the side length of the cross-section of the square welding strip, or the length of the major axis of the cross-section of the elliptical welding strip, but is not limited to these.

[0050] The width of the fixing adhesive dot 3 can be determined according to the width of the solder strip 2. In some embodiments, the width of the fixing adhesive dot 3 is 0.3mm to 6mm, and exemplary values ​​are 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3.0mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4.0mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5.0mm, 5.2mm, 5.4mm, 5.6mm, or 5.8mm, but are not limited thereto. Preferably, it is 0.75mm to 5mm, 1.2mm to 5mm, 1.5mm to 5mm, or 2mm to 5.5mm, but is not limited thereto. It should be noted that if the adhesive dots 3 are too large, i.e., the amount of adhesive applied is too large, it can easily cause uneven adhesive distribution, resulting in defects such as lamination microcracks. Moreover, in the non-busbar back-contact solar cell 1, since the adhesive dots 3 are close to the edge of the solar cell 1, if the adhesive dots 3 are too large, they can easily adhere to another solar cell 1 during the formation of the shingled structure, causing appearance defects. If the adhesive dots 3 are too small, the fixing effect on the solder ribbon 2 is poor.

[0051] Specifically, when viewed along the thickness direction of the battery cell 1, the projection of the fixing adhesive point 3 is circular, near-circular, or elliptical, but not limited to these shapes. Correspondingly, the width of the fixing adhesive point 3 is the diameter of the projection of the circular or near-circular fixing adhesive point or the length of the major axis of the projection of the elliptical fixing adhesive point, but not limited to these shapes.

[0052] Specifically, in the back contact battery string 10, multiple battery cells 1 can be located on the same plane or overlapped to form a shingled structure, but are not limited to this. When multiple battery cells 1 are located on the same plane, a separator strip is provided between adjacent battery cells 1. The color of the front of the separator strip is the same as the color of the light-receiving surface (i.e., the front) of the back contact battery cell 1, so that the front of the back contact battery string 10 has a consistent color, improving its aesthetics.

[0053] Specifically, in the back contact battery string 10, the battery cell 1 can be a whole solar cell or a segment, specifically, it can be a segment cut from a whole solar cell into two, three, or four segments, but is not limited thereto. Preferably, in some embodiments, the battery cell 1 is a segment cut from a whole solar cell, that is, a solar cell is cut along its centerline to obtain two battery cells 1.

[0054] Specifically, in the back-contact battery string 10, one edge of the battery cell 1 may be chamfered. For adjacent battery cells 1, the chamfered edges may face one direction, or the two chamfered edges may face each other, but this is not a limitation. Preferably, see [link to relevant documentation]. Figure 1 , Figure 3 , Figure 4 The chamfered edge is positioned in one direction, namely, in the first direction, the chamfered edge of the subsequent battery cell 1 is aligned with the non-chamfered edge of the preceding battery cell 1. This improves the overall appearance of the battery string.

[0055] Specifically, in the above-described embodiments, multiple welding strips 2 are disposed on the back surface of the battery cell 1, arranged along the second direction on the battery cell 1, and extending along the first direction.

[0056] More specifically, in the back-contact battery string 10, adjacent battery cells 1 are connected in series via solder ribbons 2. That is, on adjacent battery cells 1, the same solder ribbon 2 connects grid lines of different polarities to achieve series current collection and output on different battery cells 1. Exemplarily, the solder ribbon 2 may include a copper core and a cover layer covering the copper core. This cover layer may be an aluminum layer or a tin layer. The cover layer may cover all or part of the surface of the copper core. For example, the cover layer may cover all surfaces of the copper core facing the battery cell 1 and all surfaces facing away from the battery cell 1, but not the sides of the copper core. Alternatively, the cover layer may cover the entire surface of the copper core. This embodiment does not limit the specific type of cover layer to meet various needs. For example, when the cover layer is a tin layer, it may be a single tin layer or a tin alloy layer. Tin alloy layers include, but are not limited to, at least one of SnPb layers, SnBi layers, and SnAg layers.

[0057] Specifically, the solder ribbons 2 provided on the backlight side of the battery cell 1 are not limited to electrically connecting adjacent battery cells 1; some of the solder ribbons 2 can also be used to connect the busbar 200. The busbar 200 can be provided on the outside of the battery string or on the backlight side of the battery string to form a hidden busbar structure. Correspondingly, the solder ribbons 2 connecting the busbar 200 are also fixed by adhesive dots 3, and the width of the solder ribbon 2 and the width of the adhesive dots 3 also conform to the above-described relationship.

[0058] Specifically, the material of the fixing adhesive point 3 can be a UV-curable adhesive or a thermosetting adhesive (such as epoxy resin, but not limited to this), and it is an insulating material.

[0059] Specifically, the fixing adhesive dots 3 can be transparent or colored, such as black, green, or yellow, but are not limited to these. Preferably, in some embodiments, the fixing adhesive dots 3 are transparent or black, which improves the aesthetics of the battery string. More specifically, when the battery module 100 is a double-glass module, its back surface is also provided with transparent glass. By using transparent or black adhesive dots, the area of ​​the fixing adhesive dots 3 can be made to match the color of the battery cell 1 area, thereby improving the appearance consistency of the back of the battery module 100. Preferably, in other embodiments, the fixing adhesive dots 3 are fluorescent adhesive dots, that is, they can produce colors such as yellow or green when excited by specific light. Based on this embodiment, the fixing adhesive dots 3 can be used as a reference object to quickly determine the fixing status of the solder ribbon 2 through AOI inspection, thereby improving the production yield of the back contact battery string 10. It should be noted that when using the fixed adhesive point 3 as a reference object to detect the fixation of the solder ribbon 2, the ratio of the width D of the solder ribbon 2 to the width L of the fixed adhesive point 3 should be greater than 1, that is, D / L>1. Based on this, the fixed adhesive point 3 will partially extend beyond the projection surface of the solder ribbon 2. Therefore, the fixed adhesive point 3 can be used as a reference to detect the fixation of the solder ribbon 2.

[0060] Specifically, in the above-described embodiments, the first direction is the arrangement direction of the battery cells 1 in the back-contact battery string 10, and the second direction is preferably perpendicular to the first direction. Specifically, the first direction and the second direction can be the longitudinal direction and the transverse direction of the back-contact battery string 10, respectively. Of course, in other embodiments, the second direction may not be perpendicular to the first direction; this is not a limitation here.

[0061] Preferably, in some embodiments, the width of the solder ribbon 2 and the width of the fixing adhesive dots 3 in the back contact battery string 10 conform to the following relationship: 1 ≤ D / L ≤ 4, where D is the width of the fixing adhesive dots 3 and L is the width of the solder ribbon 2. The inventors have found through extensive experiments that within this range, the risk of solder ribbon 2 displacement, incomplete soldering, over-soldering, and invisible soldering is lower. Furthermore, when using thermosetting fixing adhesive dots 3, it can ensure that the adhesive dots achieve surface drying in a shorter time, thereby optimizing the fixing effect on the solder ribbon 2 and improving the production efficiency of the module. Specifically, the production cycle of a conventional back contact battery module 100 is approximately 45s to 60s, while based on this ratio, the production cycle can be shortened to approximately 40s.

[0062] Preferably, in some embodiments, the solder ribbon 2 extends beyond the coverage area of ​​the fixing adhesive point 3 in a first direction, that is, its end is located between the fixing adhesive point 3 and the edge of the battery cell 1 closest to the fixing adhesive point 3 in the first direction. Based on this embodiment, the fixing effect of the solder ribbon 2 can be further improved.

[0063] Specifically, see Figure 2 In the back-contact battery string 10, the battery cell 1 can be a battery cell with a main grid or a battery cell without a main grid, but is not limited to either. Taking a battery cell without a main grid as an example, it has a first edge 11 and a second edge 12 in a first direction, and a first pad area 13 and a second pad area 14 for forming pads are provided on both sides in the first direction. The first pad area 13 is located close to the first edge 11 and away from the second edge 12, and the second pad area 14 is located close to the second edge 12 and away from the first edge 11. In the first direction, the fixing adhesive point 3 is located between the first edge 11 and the first pad area 13; and / or the fixing adhesive point 3 is located between the second edge 12 and the second pad area 14. Based on this implementation, the connection stability between the solder ribbon 2 and the fine grid lines and pads on the battery cell 1 is improved, and current transmission loss is reduced. Specifically, multiple positive and negative fine grids 15 and 16 are arranged alternately along a first direction between the first pad region 13 and the second pad region 14. By placing the fixing adhesive dots 3 outside the first pad region 13 and the second pad region 14, the contact between the positive and negative fine grids 15 and 16 and the solder ribbon 2 between the first pad region 13 and the second pad region 14 is not affected, thus improving the current extraction efficiency. In the first pad region 13 and the second pad region 14 of the gridless solar cell, multiple positive and negative pads are arranged alternately along a second direction. During subsequent soldering, the solder ribbon 2 is soldered to these pads. When the fixing adhesive dots 3 are placed outside the first pad region 13 and the second pad region 14, the fixing adhesive dots 3 are prevented from reducing the contact area between the solder ribbon 2 and the pads, thus improving the soldering effect.

[0064] Furthermore, when using a gridless cell, the pad includes a PAD point 17 and an end line 18. The end line 18 extends along a first direction and is located between the pad and the edge of the cell 1 closest to the pad in the first direction. Based on this embodiment, the current of the fine grid covered by the fixing adhesive point 3 can be collected through the end line 18, thereby improving the overall conversion efficiency of the cell string.

[0065] Furthermore, there is an offset gap between the end line 18 and the center line of the PAD point 17 along the second direction; and the fixing adhesive point 3 is staggered from the end line 18. Based on this embodiment, the solder ribbon 2 and the fixing adhesive point 3 can be further positioned by the end line 18, thereby improving the yield of battery strings and battery modules.

[0066] Specifically, in some other embodiments, the battery cell 1 in the back-contact battery string 10 is a battery cell with main grids. The battery cell 1 has a first edge 11 and a second edge 12 in a first direction; the battery cell 1 is provided with multiple main grids arranged along the first direction. The main grids can be intermittent main grids or continuous main grids, but both ends of the main grids are at a predetermined distance from the edge of the battery cell 1 in the first direction.

[0067] Specifically, when the battery cell 1 is a battery cell with a main grid, pads for connecting the solder strip 2 can be provided at the end or middle of the main grid, but this is not limited to this. Preferably, in some embodiments, the battery cell 1 has a first pad area 13 and a second pad area 14 for forming pads on both sides in the first direction. The first pad area 13 is located near the first edge 11, and the second pad area 14 is located near the second edge 12. Based on this embodiment, the positions where the fixing adhesive dots 3 can be set can be as follows:

[0068] In the first direction, the fixing adhesive dots 3 are located between the first pad region 13 and the second pad region 14; since the solder ribbon 2 is only connected to the main grid, and the current of the fine grid on the back contact cell 1 is collected through the main grid, placing the fixing adhesive dots 3 in this region will not affect the current collection. Or

[0069] In the first direction, the fixing adhesive dots 3 are located between the first edge 11 and the first pad area 13; and between the second edge 12 and the second pad area 14. With this arrangement, after the solder ribbon 2 is placed and before the solder ribbon 2 is welded, the solder ribbon 2 is in a flat state throughout the main gate area. When the solder ribbon is welded, the contact between the main gate and the solder ribbon 2 can be further optimized, reducing losses and minimizing microcracks.

[0070] However, it should be noted that when using a solar cell 1 with a main grid, the fixing adhesive dots 3 should not overlap with the main grid lines to prevent affecting the electrical contact between the main grid and the solder strip 2.

[0071] Accordingly, when there is a main grid cell, the pad may also include a PAD point 17 and an end line 18. The end line 18 extends along a first direction and is located between the pad and the edge of the cell 1 closest to the pad in the first direction. Based on this embodiment, the current of the fine grid covered by the fixing adhesive point 3 can be collected through the end line 18, thereby improving the overall conversion efficiency of the battery string.

[0072] Furthermore, there is an offset gap between the end line 18 and the center line of the PAD point 17 along the second direction; and the fixing adhesive point 3 is staggered from the end line 18. Based on this embodiment, the solder ribbon 2 and the fixing adhesive point 3 can be further positioned by the end line 18, thereby improving the yield rate.

[0073] Example 2

[0074] See Figure 3 , Figure 4 This embodiment provides a back contact battery assembly 100, which includes the aforementioned back contact battery strings 10, a busbar 200 for connecting multiple back contact battery strings 10, and a connecting solder strip for connecting the busbar 200 to the battery strings. The connecting solder strip is also fixed to the back contact battery strings 10 by adhesive dots 3. Accordingly, the width relationship between the connecting solder strip and the adhesive dots 3 conforms to the limitations in Embodiment 1, and will not be detailed here.

[0075] Specifically, in this embodiment, the busbar 200 can be disposed between adjacent back contact battery strings 10, outside the ends of the back contact battery strings 10, or disposed on the backlight surface of the back contact battery strings 10. Preferably, in some embodiments, the busbar 200 is disposed on the backlight surface of the back contact battery strings 10. Based on this, the busbar 200 can be hidden, optimizing the front appearance, while also increasing the light-receiving area of ​​the unit component and improving the efficiency of the back contact battery assembly 100.

[0076] It is understood that, in the embodiment based on the hidden busbar 200, an insulating strip 300 is also provided below the busbar 200, and the insulating strip 300 completely covers the busbar 200. Since the positive electrode fine grid 15 and the negative electrode fine grid 16 are provided on the back-light surface of the back contact battery, the solder ribbon 2 also has a positive electrode solder ribbon and a negative electrode solder ribbon. Therefore, the insulating strip 300 can be used to insulate the busbar 200 from part of the solder ribbon 2 so as not to affect the electrical connection between the battery cells 1 of the back contact battery string 10, and the electrical connection between the back contact battery strings 10. Specifically, in this embodiment, both the insulating strip 300 and the busbar 200 extend along the second direction. Wherein, the insulating strip 300 covering the busbar 200 means that, when viewed from the direction of the back-light surface of the battery cell 1, the projection of the busbar 200 is completely located inside the insulating strip 300, or in other words, when viewed from the direction of the light-receiving surface of the battery cell 1, the insulating strip 300 can completely block the busbar 200.

[0077] Specifically, in the embodiments of this application, the busbar 200 may include a middle busbar 220 and an edge busbar 210. The middle busbar 220 is located in the middle of the back contact battery string 10 and is used to realize the parallel connection of adjacent back contact battery strings 10, more specifically, the parallel connection of adjacent back contact battery strings 10 in a first direction. The edge busbar 210 is disposed at the end of the back contact battery string 10 and is used to realize the series connection of adjacent back contact battery strings 10, more specifically, the series connection of adjacent back contact battery strings 10 in a second direction. The specific location and form of the busbar 200 are not limited here to meet various needs.

[0078] It is understood that in such embodiments, the back contact battery assembly 100 may further include a frame, a back sheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back sides of the back contact battery, the photovoltaic glass, adjacent battery cells 1, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0079] Photovoltaic glass can be applied to the encapsulating film on the front side of the back contact battery. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%, protecting the back contact battery while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back contact battery together, providing sealing, insulation, and waterproofing / moisture protection for the battery.

[0080] The backsheet can be attached to the adhesive film on the back of the back contact battery. The backsheet protects and supports the back contact battery, providing reliable insulation, water resistance, and aging resistance. Multiple options are available for the backsheet, typically tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, back contact battery, adhesive film, and photovoltaic glass can be integrated into a frame. The frame serves as the main external support structure for the entire back contact battery module 100, providing stable support and installation. For example, the back contact battery module 100 can be installed at the desired location via the frame.

[0081] Example 3

[0082] See Figure 5This embodiment discloses a photovoltaic system 1000, which includes the back contact battery module 100 of the above embodiment. In the photovoltaic system 1000, the back contact battery modules 100 can be electrically connected in parallel or in series, and the specific configuration can be selected according to actual needs.

[0083] In this embodiment, the photovoltaic system 1000 can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system 1000 are not limited to these; that is to say, the photovoltaic system 1000 can be applied in all fields that require the use of solar energy to generate electricity.

[0084] Taking a photovoltaic power generation system network as an example, the photovoltaic system 1000 may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules 100. For example, multiple battery modules 100 may form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can combine the current generated by the photovoltaic array. The combined current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to realize solar power supply.

[0085] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0086] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A back-contact battery string, characterized in that, include: Multiple solar cells are arranged along a first direction; Multiple welding strips are used to electrically connect adjacent solar cells; Multiple welding strips are arranged on the battery cell along a second direction, the welding strips extend along a first direction, and the first and second directions are intersected; as well as A fixing adhesive dot is disposed on the battery cell to fix the solder ribbon to the battery cell; The width of the solder strip and the width of the fixing adhesive dot conform to the following relationship: 0.75≤D / L<6; In the formula, D is the width of the fixed adhesive dot, and L is the width of the solder strip.

2. The back contact battery string as described in claim 1, characterized in that, The width of the welding strip is 0.4mm to 3mm; and / or The width of the fixing adhesive dots is 0.75mm to 5mm.

3. The back contact battery string as described in claim 1, characterized in that, The width of the solder strip and the width of the fixing adhesive dot conform to the following relationship: 1≤D / L≤4; In the formula, D is the width of the fixed adhesive dot, and L is the width of the solder strip.

4. The back contact battery string as described in claim 1, characterized in that, The solder strip extends beyond the coverage area of ​​the fixing adhesive dot in a first direction.

5. The back contact battery string as described in any one of claims 1 to 4, characterized in that, The fixing adhesive dots are transparent or black.

6. The back contact battery string as described in any one of claims 1 to 4, characterized in that, The fixing adhesive dots are fluorescent adhesive dots; The width of the solder strip and the width of the fixing adhesive dot conform to the following relationship: D / L > 1; In the formula, D is the width of the fixed adhesive dot, and L is the width of the solder strip.

7. The back contact battery string as described in claim 1, characterized in that, The solar cell is a gridless solar cell, and the solar cell has a first edge and a second edge in a first direction; The battery cell has a first pad area and a second pad area on both sides in a first direction for forming pads. The first pad area is located near the first edge, and the second pad area is located near the second edge. In a first direction, the fixing adhesive dots are disposed between the first edge and the first pad area; and / or In the first direction, the fixing adhesive dots are located between the second edge and the second pad area.

8. The back contact battery string as described in claim 1, characterized in that, The battery cell has a first edge and a second edge in a first direction; the battery cell is provided with main grid lines arranged along the second direction; The battery cell has a first pad area and a second pad area on both sides in a first direction for forming pads. The first pad area is located near the first edge, and the second pad area is located near the second edge. In a first direction, the fixing adhesive dots are disposed between the first pad region and the second pad region; and / or In a first direction, the fixing adhesive dots are disposed between the first edge and the first pad area; and / or In the first direction, the fixing adhesive dots are located between the second edge and the second pad area.

9. The back contact battery string as described in claim 7 or 8, characterized in that, The pad includes a PAD point and an end line, the end line extends along a first direction, and there is an offset spacing between the end line and the center line of the PAD point along a second direction; The fixing adhesive dots are staggered from the end lines.

10. The back contact battery string as described in claim 9, characterized in that, The solder strip is connected to the PAD point, and the end line is exposed outside the solder strip.

11. A back-contact battery assembly, characterized in that, Includes the back contact battery string as described in any one of claims 1 to 10.

12. A photovoltaic system, characterized in that, Includes the back contact battery assembly as described in claim 11.

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