Battery string, battery assembly, and photovoltaic system

Abstract

A battery string (100), a battery assembly (200), and a photovoltaic system (1000). In the battery string (100), first auxiliary grids (11) are connected to first main grids (13) and are disconnected at second main grids (14), second auxiliary grids (12) are connected to the second main grids (14) and are disconnected at the first main grids (13), first ribbons (20) are connected to the first main grids (13) in the previous back contact solar cell (10) and the second main grids (14) in the next back contact solar cell (10), and second ribbons (30) are connected to the second main grids (14) in the previous back contact solar cell (10) and the first main grids (13) in the next back contact solar cell (10). A first gap (111) is formed between a disconnection point formed by the disconnection of each first auxiliary grid (11) and each second main grid (14), and a second gap (121) is formed between a disconnection point formed by the disconnection of each second auxiliary grid (12) and each first main grid (13). At a position corresponding to a spacer region (101) between two back contact solar cells (10), each first ribbon (20) forms a first suspended segment (21) at the spacer region (101), or each second ribbon (30) forms a second suspended segment (31) at the spacer region (101), and the lengths of the first suspended segment (21) and the second suspended segment (31) are both less than the width (L1) of the first gap (111) and the width (L2) of the second gap (121).

Description

Battery strings, battery panels and photovoltaic systems

[0001] Priority information

[0002] This application claims priority and benefits of patent application No. 202420053311.3 filed with the State Intellectual Property Office of China on January 9, 2024, and the entire text of which is incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of solar cells, and in particular to a battery string, a battery assembly and a photovoltaic system. Background Art

[0004] In related technologies, a secondary grid and a main grid are usually provided on the back side of a back-contact battery. When forming a battery string, the main grids of two adjacent battery cells with different polarities are aligned, and then welding ribbons are welded on the main grids to connect the two battery cells in series, and every other welding ribbon is cut off to form a complete battery string.

[0005] However, in such a technical solution, since the soldering ribbon is cut off and a portion thereof is suspended, the suspended portion is easily bent and contacts the auxiliary grid with a different polarity from the soldering ribbon, thereby causing a short circuit. Summary of the Invention

[0006] The present application provides a battery string, a battery assembly and a photovoltaic system.

[0007] The present application is implemented as follows: the battery string of the embodiment of the present application includes:

[0008] A plurality of back-contact solar cells arranged at intervals along a first direction, the back-contact solar cells having a plurality of first auxiliary grids, a plurality of second auxiliary grids, a plurality of first main grids, and a plurality of second main grids, the plurality of first auxiliary grids and the plurality of second auxiliary grids being alternately and spaced apart in parallel along the first direction, the plurality of first main grids and the plurality of second main grids being alternately and spaced apart in parallel along a second direction, the first direction intersecting the second direction, the first auxiliary grid being connected to the first main grid and disconnected at the second main grid, the second auxiliary grid being connected to the second main grid and disconnected at the first main grid; in two adjacent back-contact solar cells, the first main grid of one corresponds to the second main grid of the other in the first direction, and a spacer is provided between the two adjacent back-contact solar cells;

[0009] a plurality of first welding ribbons and a plurality of second welding ribbons alternately arranged in sequence along the second direction, wherein the first welding ribbons and the second welding ribbons are parallel to the first busbar and the second busbar and are correspondingly arranged on the first busbar and the second busbar; the first welding ribbons connect the first busbar in the preceding back-contact solar cell and the second busbar in the succeeding back-contact solar cell, and the second welding ribbons connect the second busbar in the preceding back-contact solar cell and the first busbar in the succeeding back-contact solar cell;

[0010] Wherein, in the second direction, there is a first gap between the disconnection point formed by disconnection of the first auxiliary gate and the second main gate, and there is a second gap between the disconnection point formed by disconnection of the second auxiliary gate and the first main gate;

[0011] At a position corresponding to the spacing area, the first welding ribbon or the second welding ribbon is cut off. When the first welding ribbon is cut off, the first welding ribbon forms a first suspended section at the spacing area, and the length of the first suspended section is smaller than the width of the first gap and the second gap.

[0012] When the second welding ribbon is cut off, the second welding ribbon forms a second suspended segment at the spacing area, and the length of the second suspended segment is smaller than the width of the first gap and the second gap.

[0013] Furthermore, the number of the back-contact solar cells is greater than two, and in two adjacent spacer areas, the first welding ribbon in one of the spacer areas is cut off, and the second welding ribbon in the other spacer area is cut off.

[0014] Furthermore, the width of the first gap is 0.9 mm-1.2 mm; the width of the second gap is 0.9 mm-1.2 mm.

[0015] Furthermore, in the first direction, the distance between two adjacent back-contact solar cells is 0.3 mm-1.2 mm.

[0016] Furthermore, the width of the first gap is greater than the width of the second gap.

[0017] Furthermore, at a corresponding position of the spacer area, a first shielding layer is provided on a side of the first welding ribbon facing the light-receiving surface of the back-contact solar cell.

[0018] A second shielding layer is provided on a side of the second welding ribbon facing the light-receiving surface of the back-contact solar cell.

[0019] Furthermore, the colors of the first shielding layer and the second shielding layer correspond to the colors of the back contact solar cell.

[0020] Furthermore, the ends of the first suspended segment and the second suspended segment are coated with an insulating coating, and the insulating coating wraps the ends of the first suspended segment and the second suspended segment.

[0021] Furthermore, the color of the insulating coating corresponds to the color of the back contact solar cell.

[0022] The present application also provides a battery assembly, which includes several of the above-mentioned battery strings.

[0023] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0024] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a module schematic diagram of a photovoltaic system provided in an embodiment of the present application.

[0026] FIG2 is a module schematic diagram of a battery assembly provided in an embodiment of the present application.

[0027] FIG3 is a schematic diagram of a planar structure of a battery string provided in an embodiment of the present application;

[0028] FIG4 is another planar structural diagram of a battery string provided in an embodiment of the present application;

[0029] FIG5 is another schematic plan view of the structure of a battery string according to an embodiment of the present application;

[0030] FIG6 is a schematic cross-sectional view of the battery string in FIG5 at the position of the first welding strip along the first direction;

[0031] FIG7 is a schematic cross-sectional view of the battery string in FIG5 at the position of the second welding strip along the first direction;

[0032] FIG8 is a schematic cross-sectional view of the battery string in FIG3 at the position of the first welding strip along the first direction;

[0033] FIG9 is a schematic cross-sectional view of the battery string in FIG3 at the position of the second welding strip along the first direction.

[0034] Description of main component symbols:

[0035] Photovoltaic system 1000, battery assembly 200, battery string 100, back-contact solar cell 10, first auxiliary grid 11, second auxiliary grid 12, first main grid 13, second main grid 14, first welding ribbon 20, first suspended section 21, second welding ribbon 30, second suspended section 31, first bus bar 40, second bus bar 50, first shielding layer 60, second shielding layer 70, insulating coating 80. Modes for Carrying Out the Invention

[0036] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and are not to be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present application and are not intended to limit the present application.

[0037] In the description of this application, it should be understood that the terms "up", "down", "left", "right", "horizontal", "longitudinal", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They 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 direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on this application.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this application, "several" means two or more, unless otherwise specifically defined.

[0039] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0040] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use scenarios of other materials.

[0041] Example 1

[0042] 1 and 2 , the photovoltaic system 1000 in the embodiment of the present application may include the battery assembly 200 in the embodiment of the present application, and the battery assembly 200 in the embodiment of the present application may include several battery strings 100 in the embodiment of the present application.

[0043] 3 to 6 , the cell string 100 in the embodiment of the present application may include a plurality of back-contact solar cells 10 , a plurality of first soldering ribbons 20 , and a plurality of second soldering ribbons 30 .

[0044] A plurality of back-contact solar cells 10 may be arranged at intervals along a first direction. The back-light surface of the back-contact solar cell 10 has a plurality of first sub-grids 11 , a plurality of second sub-grids 12 , a plurality of first main grids 13 and a plurality of second main grids 14 .

[0045] As shown in Figures 3-5, a plurality of first auxiliary grids 11 and a plurality of second auxiliary grids 12 are arranged alternately and parallel to each other along a first direction, while a plurality of first main grids 13 and a plurality of second main grids 14 are arranged alternately and parallel to each other along a second direction, with the first direction intersecting the second direction. The first direction may be the direction in which the battery string 100 is connected (i.e., the transverse direction in Figure 3), and the second direction may be a direction perpendicular to the direction in which the battery string 100 is connected (i.e., the longitudinal direction in Figure 3), with the two directions being perpendicular to each other.

[0046] Among them, the first auxiliary grid 11 and the second auxiliary grid 12 are set corresponding to the first doping layer (not shown in the figure) of the back contact solar cell 10, and the second auxiliary grid 12 is set corresponding to the second doping layer (not shown in the figure) of the back contact solar cell. One of the first doping layer and the second doping layer is a P-type doping layer, and the other is an N-type doping layer.

[0047] As shown in FIG3 to FIG5 , in the back-contact solar cell 10 , the first auxiliary grid 11 is connected to the first main grid 13 and disconnected at the second main grid 14 , and the second auxiliary grid 12 is connected to the second main grid 14 and disconnected at the first main grid 13 .

[0048] In two adjacent back-contact solar cells 10, the first main grid 13 of one back-contact solar cell 10 corresponds to the second main grid 14 of the other back-contact solar cell 10 in a first direction (that is, as shown in Figures 3-5, the first main grid 13 and the second main grid 14 of the two adjacent back-contact solar cells 10 are basically located on the same straight line), and there is a spacer area 101 between the two adjacent back-contact solar cells.

[0049] A plurality of first welding ribbons 20 and a plurality of second welding ribbons 30 are alternately arranged in sequence along the second direction. The first welding ribbons 20 and the second welding ribbons 30 are parallel to the first busbar 13 and the second busbar 14 and are correspondingly arranged above the first busbar 13 and the second busbar 14 (that is, as shown in Figures 3 to 5, the first welding ribbons 20 and the second welding ribbons 30 are aligned with and overlap with the first busbar 13 and the second busbar 14). The first welding ribbons 20 connect the first busbar 13 in the previous back-contact solar cell 10 and the second busbar 14 in the next back-contact solar cell 10, and the second welding ribbons 30 connect the second busbar 14 in the previous back-contact solar cell 10 and the first busbar 13 in the next back-contact solar cell 10.

[0050] Specifically, as shown in Figures 3-5 , each first welding ribbon 20 alternately connects a plurality of first busbars 13 and a plurality of second busbars 14 in the first direction. Similarly, each second welding ribbon 30 alternately connects a plurality of second busbars 14 and a first busbar 13 in the first direction. That is, in the first direction, the first welding ribbon 20 connects the first busbar 13 of the Nth back-contact solar cell and the second busbar 14 of the N+1th back-contact solar cell in parallel, while the second welding ribbon 30 connects the second busbar 14 of the Nth back-contact solar cell and the first busbar 13 of the N+1th back-contact solar cell in parallel.

[0051] As shown in Figures 3-4, in the second direction, there is a first gap 111 between the disconnection point formed by the disconnection of the first auxiliary gate 11 and the second main gate 14, and the width of the first gap 111 is L1 in Figures 3-6. There is a second gap 121 between the disconnection point formed by the disconnection of the second auxiliary gate 12 and the first main gate 13, and the width of the second gap 121 is L2 in Figures 3-6.

[0052] The first welding ribbon 20 or the second welding ribbon 30 is cut off at the position corresponding to the spacing area 101. As shown in FIG3 , when the first welding ribbon 20 is cut off, the first welding ribbon 20 forms a first suspended section 21 at the spacing area 101. The length L3 of the first suspended section 21 is less than the width L1 of the first gap 111 and the width L2 of the second gap 121.

[0053] As shown in FIG. 4 , when the second welding ribbon 30 is cut, the second welding ribbon 30 forms a second suspended section 31 at the spacing area 101 , and the length L4 of the second suspended section 31 is smaller than the width L1 of the first gap 111 and the width L2 of the second gap 121 .

[0054] Please refer to Figure 7. In this application, a number of first welding points 131 are provided on the first main grid 13, and a number of second welding points 141 are provided on the second main grid 14. The first welding strip 20 and the second welding strip 30 are connected to the first main grid 13 and the second main grid 14 through the first welding points 131 and the second welding points 141.

[0055] It should be noted that, as shown in Figure 3, the cut first welding strip 20 will form two endpoints, which will form two first suspended segments 21, one of which is connected to the first main grid 13, and the other is connected to the second main grid 14.

[0056] The first suspended section 21 connected to the first main gate 13 refers to the part between the end point close to the first main gate 13 and the first welding point 131 on the first main gate 13 closest to the spacer area 101 when it is cut off. The length L3 of the first suspended section 21 is the distance between the end point and the first welding point 131 on the first main gate 13 closest to the spacer area 101. The first suspended section 21 connected to the second main gate 14 refers to the part between the end point close to the second main gate 14 and the second welding point 141 on the second main gate 14 closest to the spacer area 101 when it is cut off. The length L3 of the first suspended section 21 is the distance between the end point and the second welding point 141 on the second main gate 14 closest to the spacer area 101.

[0057] Similarly, as shown in FIG. 4 , the cut second welding strip 30 also forms two endpoints, which form two second suspended segments 31 , one of which is connected to the second main grid 14 , and the other is connected to the first main grid 13 .

[0058] The second suspended section 31 connected to the first main gate 13 refers to the part between the end point close to the first main gate 13 and the first welding point 131 on the first main gate 13 closest to the spacer area 101 when it is cut off. The length L4 of the second suspended section 31 is the distance between the end point and the first welding point 131 on the first main gate 13 closest to the spacer area 101. The second suspended section 31 connected to the second main gate 14 refers to the part between the end point close to the second main gate 14 and the second welding point 141 on the second main gate 14 closest to the spacer area 101 when it is cut off. The length L4 of the second suspended section 31 is the distance between the end point and the second welding point 141 on the second main gate 14 closest to the spacer area 101.

[0059] In the cell string 100, cell assembly 200, and photovoltaic system 1000 of the embodiments of the present application, a first welding ribbon 20 connects the first busbar 13 of the preceding back-contact solar cell and the second busbar 14 of the succeeding back-contact solar cell, and a second welding ribbon 30 connects the second busbar 14 of the preceding back-contact solar cell and the first busbar 13 of the succeeding back-contact solar cell. In the second direction, a first gap 111 is defined between the break point of the first auxiliary grid 11 and the second welding ribbon 30, and a second gap 121 is defined between the break point of the second auxiliary grid 12 and the first welding ribbon 20. At the location corresponding to the spacer 101, either the first welding ribbon 20 or the second welding ribbon 30 is cut. When the first welding ribbon 20 is cut, a first overhanging section 21 is formed at the spacer 101. The length L3 of the first overhanging section 21 is less than the width L1 of the first gap 111 and the width L2 of the second gap 121 (i.e., L3 < L1 and L3 < L2). When the second welding ribbon 30 is cut, the second welding ribbon 30 forms a second suspended segment 31 at the spacer 101. The length L4 of the second suspended segment 31 is less than the width L1 of the first gap 111. Thus, during the formation of the battery string, by controlling the length L3 of the first suspended segment 21 to be less than the width L1 of the first gap 111 and the length L4 of the second suspended segment 31 to be less than the width L1 of the first gap 111 and the width L2 of the second gap 121 (i.e., L4 < L1 and L4 < L2), the first suspended segment 21 is prevented from contacting the second auxiliary grid 12 when bent, and the second suspended segment 31 is prevented from contacting the first auxiliary grid 11 when bent, thereby preventing short circuits and ensuring the stability and reliability of the battery string.

[0060] As shown in Figures 3 and 4, in an embodiment of the present application, the battery string 100 further includes a first bus bar 40 and a second bus bar 50 located at both ends of the battery string 100, respectively. The first bus bar 40 can be connected to all the second welding ribbons 30, and the second bus bar 50 can be connected to all the first welding ribbons 20, thereby realizing the bus output of the battery string 100.

[0061] It is not difficult to understand that, as shown in Figures 3 and 4, in a possible embodiment, if the cell string has only two back-contact solar cells 10, then the cell string has only one spacer 101, and within the spacer 101, either the first welding ribbon 20 is cut off (as shown in Figure 3) or the second welding ribbon 30 is cut off (as shown in Figure 4).

[0062] Please refer to Figure 5. In some embodiments, the number of back-contact solar cells 10 may be greater than two. In this case, in two adjacent spacers 101, the first welding ribbon 20 in one spacer 101 is cut off, and the second welding ribbon 30 in the other spacer 101 is cut off.

[0063] In this way, if the number of back-contact solar cells 10 in the cell string 100 exceeds two, the cut-off solder strips in two adjacent spacers 101 are different, which can achieve smooth current collection and transmission to avoid short circuits.

[0064] Specifically, in this case, if the first welding ribbon 20 in the Nth spacing area 101 is cut off, then the second welding ribbon 30 in the N+1th spacing area 101 is cut off, where N is a positive integer.

[0065] In some embodiments, the width L1 of the first gap 111 may be greater than the width L2 of the second gap 121, that is, L2>L1. This can effectively prevent accidental contact between the first auxiliary grid 11 and the second main grid 13. For example, when the width of the second welding ribbon 30 is wider than the width of the first welding ribbon 20, setting the width L1 of the first gap 111 larger can prevent the first auxiliary grid 11 and the second main grid 13 from contacting each other.

[0066] It is understood that in the embodiments of the present application, the battery assembly 200 may further include a metal frame, a backsheet, photovoltaic glass, and an adhesive film (not shown). The adhesive film may be filled between the front surface and photovoltaic glass, the back surface and the backsheet, and adjacent cells of the back-contact solar cell 10. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film may be EVA film or POE film. The specific choice may be based on actual conditions and is not limited here.

[0067] Photovoltaic glass can cover the adhesive film on the front surface of the back-contact solar cell 10. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and excellent physical, mechanical, and optical properties. For example, ultra-clear glass can have a light transmittance of over 92%, protecting the back-contact solar cell 10 while minimizing the impact on the efficiency of the back-contact solar cell 10. The adhesive film can also bond the photovoltaic glass and the back-contact solar cell 10 together, providing sealing, insulation, and waterproofing of the back-contact solar cell 10.

[0068] A backsheet can be attached to the film on the back of the back-contact solar cell 10. The backsheet protects and supports the back-contact solar cell 10, providing reliable insulation, water resistance, and aging resistance. A variety of backsheet options are available, typically including tempered glass, organic glass, and aluminum alloy TPT composite film. The specific configuration depends on the specific situation and is not limited here. The entire assembly consisting of the backsheet, back-contact solar cell 10, film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the primary external support structure for the entire battery assembly 200 and provides stable support and installation for the battery assembly 200. For example, the metal frame can be used to install the battery assembly 200 in the desired location.

[0069] Furthermore, in this embodiment, the photovoltaic system 1000 can be applied in photovoltaic power stations, such as ground-based power stations, rooftop power stations, and water-based power stations. It can also be applied to equipment or devices that use 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. In other words, the photovoltaic system 1000 can be applied in all fields that require solar power generation. 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 assemblies 200. For example, multiple battery assemblies 200 may form multiple photovoltaic arrays. The photovoltaic arrays are connected to a combiner box, which can combine the current generated by the photovoltaic arrays. The combined current flows through the inverter to convert it into the AC power required by the mains power grid and then connects to the mains power grid to achieve solar power supply.

[0070] Example 2

[0071] In some embodiments, the width L1 of the first gap 111 may be 0.9 mm-1.2 mm, and the width L2 of the second gap 121 may be 0.9 mm-1.2 mm.

[0072] In this way, it is possible to avoid the width L1 of the adjacent first gap 111 and the width L2 of the second gap 121 being too small, which would result in the length L3 of the first suspended section 21 and the length L4 of the second suspended section 31 needing to be set smaller, thereby increasing the process difficulty when cutting the first welding ribbon 20 and the second welding ribbon 30. It is also possible to avoid the width L1 of the first gap 111 and the width L2 of the second gap 121 being too large, which would result in a reduction in the area of ​​the back-contact solar cell 20 that does not have the first fine grid 11 and the second fine grid 12, thereby affecting the efficiency of the back-contact solar cell 10.

[0073] Specifically, in such an embodiment, the width L1 of the first gap 111 can be, for example, 0.9 mm, 0.95 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, or any value between 0.9 mm and 1.2 mm, and is not specifically limited here. The width L2 of the second gap 121 can be, for example, 0.9 mm, 0.95 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, or any value between 0.9 mm and 1.2 mm, and is not specifically limited here. The width L1 of the first gap 111 can be the same as or different from the width of the second gap 121, and is not specifically limited here.

[0074] Example 3

[0075] In some embodiments, in the first direction, the distance between two adjacent back-contact solar cells 10 (ie, the width of the spacer 101 in the first direction) may be 0.3 mm-1.2 mm.

[0076] In this way, it is possible to avoid the distance between two adjacent back-contact solar cells 10 being too small, which would cause inconvenience in operation when cutting the first welding ribbon 20 and the second welding ribbon 30, or even damage to the back-contact solar cell 10. It is also possible to avoid the distance between two adjacent back-contact solar cells 10 being too large, which would cause the number of back-contact solar cells 10 in a single cell string 100 of the same size to be reduced, and the length of the first suspended segment 21 and the second suspended segment 31 to be too long.

[0077] Specifically, in such an embodiment, the distance between two adjacent back-contact solar cells 10 may be, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm or any value between 0.3 mm and 1.2 mm, and is not limited here.

[0078] Example 4

[0079] Referring to Figures 6 and 7 , in some embodiments, a first shielding layer 60 is provided on the side of the first welding ribbon 20 facing the light-receiving surface of the back-contact solar cell 10 (i.e., the bottom surface in Figures 6 and 7 ) at the corresponding position of the spacer 101. A second shielding layer 70 is provided on the side of the second welding ribbon 30 facing the light-receiving surface of the back-contact solar cell 10.

[0080] In this way, the first shielding layer 60 is coated on the area where the first welding strip 20 is exposed from the spacer area 101, and the second shielding layer 70 is coated on the area where the second welding strip 30 is exposed from the spacer area 101. This can shield the first welding strip 20 and the second welding strip 30, and prevent the first welding strip 20 and the second welding strip 30 from being directly exposed and affecting the appearance.

[0081] Furthermore, in some embodiments, the color of the first shielding layer 60 and the second shielding layer 70 may be the same as the color of the back-contact solar cell 10. For example, when the back-contact solar cell 10 is blue, the color of the first shielding layer 60 and the second shielding layer 70 may also be blue; when the back-contact solar cell 10 is gold, the color of the first shielding layer 60 and the second shielding layer 70 may also be gold.

[0082] In this way, the color of the exposed positions of the first welding ribbon 20 and the second welding ribbon 30 can be made the same as the diffraction of the back contact solar cell to avoid seeing the first welding ribbon 20 and the second welding ribbon 30 of different colors from the front at the spacer area 101, thereby ensuring a beautiful appearance.

[0083] Example 5

[0084] Referring to FIG. 8 and FIG. 9 , in some embodiments, the ends of the first suspended segment 21 and the second suspended segment 31 are coated with an insulating coating 80 , and the insulating coating 80 wraps the ends of the first suspended segment 21 and the second suspended segment 31 .

[0085] In this way, the provision of the insulating coating 80 can prevent the first welding ribbon 20 and the second welding ribbon 30 from unexpectedly causing conductive contact between the two ends after being cut, thereby improving the reliability of the battery string 100.

[0086] Furthermore, in some embodiments, the color of the insulating coating 80 may correspond to the color of the back-contact solar cell 10. In this way, the aesthetic appearance of the entire cell string 100 can be ensured.

[0087] Throughout this specification, reference to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations 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 any one or more embodiments or examples.

[0088] In addition, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery string, comprising:several back-contact solar cells arranged at intervals in a first direction, wherein each back-contact solar cell comprises several first fingers, several second fingers, several first busbars and several second busbars, the first finger and the second finger are sequentially and alternately disposed in parallel at intervals in the first direction, the first busbar and the second busbar are sequentially and alternately arranged in parallel at intervals in a second direction, the first direction intersects with the second direction, the first fingers are connected with the first busbars and are disconnected at a position where the second busbars is provided, and the second fingers are connected with the second busbars and are disconnected at a position where the first busbars is provided; in two adjacent back-contact solar cells, the first busbars of one back-contact solar cell correspond to the second busbars of an other back-contact solar cell in the first direction, and spacer region are provided between two adjacent back-contact solar cells; andseveral first ribbons and several second ribbons, wherein the first ribbon and the second ribbon are sequentially and alternately arranged at intervals in the second direction, wherein the first ribbons and the second ribbons are parallel to the first busbars and the second busbars and are correspondingly disposed on the first busbars and the second busbars; the first ribbon is connected with the first busbars in one back-contact solar cell of the two adjacent back-contact solar cells and the second busbars in an other back-contact solar cell of the two adjacent back-contact solar cells, and the second ribbon is connected with the second busbars in one back-contact solar cells of the two adjacent back-contact solar cells and the first busbars in the other back-contact solar cells of the two adjacent back-contact solar cells;in the second direction, there are first gaps between the second busbar and disconnection point formed by disconnecting the first finger, and there are second gap between the first busbar and disconnection point formed by disconnecting the second finger;at a position corresponding to each spacer region, the first ribbon or the second ribbon is cut off, in a case where the first ribbon is cut off, the first ribbon forms a first suspended segment at the spacer region, and a length of the first suspended segment is less than a width of the first gap and a width of the second gap; andin a case where the second ribbon is cut off, the second ribbon forms a second suspended segment at the spacer region, and a length of the second suspended segment is less than the width of the first gap and the width of the second gap.

2. The battery string according to claim 1, wherein a number of the back-contact solar cells is greater than two, in two adjacent spacer regions, the first ribbon in one spacer region is cut off, and the second ribbon in an other spacer region is cut off.

3. The battery string according to claim 1, wherein the width of the first gap ranges from 0.9mm to 1.2mm; and the width of the second gap ranges from 0.9mm to 1.2mm.

4. The battery string according to claim 1, wherein in the first direction, a distance between two adjacent back-contact solar cells ranges from 0.3mm to 1.2mm.

5. The battery string according to claim 1, wherein the width of the first gap is greater than the width of the second gap.

6. The battery string according to claim 1, wherein at the position corresponding to each spacer region, a side of the first ribbon facing a light-receiving surface of the back-contact solar cell is provided with a first shielding layer, anda side of the second ribbon facing the light-receiving surface of the back-contact solar cell is provided with a second shielding layer.

7. The battery string according to claim 6, wherein a color of the first shielding layer and a color of the second shielding layer correspond to a color of the back-contact solar cell.

8. The battery string according to claim 1, wherein an end portion of the first suspended segment and an end portion of the second suspended segment are coated with insulating coatings, and the insulating coatings wrap the end portion of the first suspended segment and the end portion of the second suspended segment.

9. The battery string according to claim 8, wherein a color of the insulating coating corresponds to the color of the back-contact solar cell.

10. A battery assembly, comprising several battery strings according to any of claims 1-9.

11. A photovoltaic system, comprising the battery assembly according to claim 10.

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