Battery string and photovoltaic module

Abstract

The present application relates to the technical field of photovoltaic modules, and specifically discloses a battery string and a photovoltaic module. The battery string comprises: a cell without a busbar; a plurality of fingers, the plurality of fingers being arranged on the surface of the cell at intervals in a first direction; and a plurality of solder ribbons, the plurality of solder ribbons being arranged at intervals in a second direction and being connected to the surface of the cell, each solder ribbon being at least connected to a part of the plurality of fingers, and the second direction being perpendicular to the first direction. The number of the solder ribbons is x, the width of the solder ribbons in the second direction is y, and x and y satisfy the relation: -0.0105x+0.4186≤y≤-0.01x+0.48, wherein the unit of x is piece, and the unit of y is mm.

Description

Battery string and photovoltaic module

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 28, 2023, with application number 202310778450.2 and invention name “A battery string and photovoltaic module”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of photovoltaic modules, and in particular to a battery string and a photovoltaic module. Background Art

[0003] A cell string is the core component of a photovoltaic module, converting solar energy into electricity. A cell string consists of multiple cells arranged in sequence. The cell surfaces are equipped with a main grid and a secondary grid, which collect the current generated by the cells. The main grid and the secondary grid are cross-connected, and the main grid collects the current collected by the secondary grid, thus aggregating the current generated by the cells.

[0004] Typically, a slurry is printed on the surface of a cell by screen printing to form multiple mutually perpendicular auxiliary grids and multiple main grids on the surface of the cell. The current generated by the cell is collected and aggregated by the multiple auxiliary grids and multiple main grids in order to collect the current generated by the entire cell. However, setting up multiple main grids and auxiliary grids on the surface of the cell consumes a lot of slurry, thus increasing the cost of the cell. In addition, the auxiliary grids and main grids will block the upper surface of the cell, affecting the efficiency of the upper surface of the cell in absorbing light, thereby affecting the photoelectric conversion efficiency of the cell.

[0005] In related technologies, the production cost of solar cells is typically reduced, while the photovoltaic conversion efficiency of the cells is improved, by reducing the number of main grids and auxiliary grids, or even eliminating the main grid. As shown in Figure 1, only the auxiliary grid is installed on the surface of the cell. A welding ribbon is placed in the position of the main grid, and the auxiliary grid is connected to the auxiliary grid through the welding ribbon to collect the current collected by the auxiliary grid.

[0006] However, simply reducing the number of main grids or auxiliary grids, or not providing a main grid, still cannot effectively improve the photoelectric conversion efficiency of the solar cell.

[0007] Summary of the Invention

[0008] The purpose of this application is to provide a battery string and a photovoltaic module.

[0009] Specifically, this application involves the following aspects:

[0010] In a first aspect, the present application discloses a battery string, comprising a battery cell without a main grid; a plurality of auxiliary grids, wherein the plurality of auxiliary grids are arranged at intervals along a first direction on the surface of the battery cell; a plurality of welding strips, wherein the plurality of welding strips are arranged at intervals along a second direction and connected to the surface of the battery cell, and each of the welding strips is connected to at least a portion of the plurality of auxiliary grids, and the second direction is perpendicular to the first direction; the number of the welding strips is x, and the width of the welding strip along the second direction is y, satisfying -0.0105x+0.4186≤y≤-0.01x+0.48, where the unit of x is root and the unit of y is mm.

[0011] In a second aspect, the present application further discloses a battery string, comprising a battery cell without a main grid; a plurality of auxiliary grids, wherein the plurality of auxiliary grids are spaced apart along a first direction on the surface of the battery cell; a plurality of welding strips, wherein the plurality of welding strips are spaced apart along a second direction and connected to the surface of the battery cell, and each welding strip is connected to at least a portion of the plurality of auxiliary grids, wherein the second direction is perpendicular to the first direction; wherein the number of the welding strips is x, the number of the auxiliary grids is z, and 0.1754x is satisfied. 2 -7.2048x+115.26≤z≤0.0828x 2 -3.7862x+100.26, where x and z are in roots.

[0012] In a third aspect, the present application discloses a photovoltaic module, which includes the battery string described in the first aspect and / or the second aspect, wherein the battery string includes a plurality of battery strings, and the plurality of battery strings are arranged at intervals.

[0013] This application discloses a cell string and a photovoltaic module, the cell string comprising: a cell without a main grid; a plurality of auxiliary grids spaced apart along a first direction on the surface of the cell; a plurality of welding ribbons spaced apart along a second direction and connected to the surface of the cell, with each welding ribbon connected to at least a portion of the plurality of auxiliary grids, the second direction being perpendicular to the first direction; the number of welding ribbons being x, the width of the welding ribbons along the second direction being y, such that -0.0105x+0.4186≤y≤-0.01x+0.48, where x is in units of ribbons and y is in units of mm. In this application, by setting the width y of the welding ribbons along the second direction to the number of welding ribbons x, such that y is greater than or equal to -0.0105x+0.4186 and less than or equal to -0.01x+0.48, the photovoltaic conversion efficiency of the cell is improved by limiting the range of the welding ribbon width y under different welding ribbon number x.

[0014] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] FIG1 shows the photovoltaic conversion efficiency of a half-cell with no main grid on the front side, with the number of solder strips x, the width of the solder strips along the second direction y, and the number of auxiliary grids z as variables.

[0017] FIG2 shows the quantitative relationship between the number x of solder strips, the width y of the solder strips along the second direction, and the number z of auxiliary grids when there is no main grid on the front side of a half-cell.

[0018] FIG3 shows a graphical relationship between the number x of solder strips and the width y of the solder strips along the second direction.

[0019] FIG4 shows a graphical relationship between the number of solder strips x and the number of auxiliary grids z.

[0020] FIG5 shows a first structural diagram of the battery cell according to an embodiment of the present application.

[0021] FIG6 shows a second structural diagram of the battery cell according to an embodiment of the present application.

[0022] FIG7 is a schematic structural diagram of the joining point in an embodiment of the present application.

[0023] FIG8 shows a schematic diagram of the adhesive points described in the embodiment of the present application.

[0024] FIG9 shows a second schematic diagram of the adhesive points described in an embodiment of the present application.

[0025] FIG10 shows a side view of the battery cell described in an embodiment of the present application.

[0026] Reference numerals: 10: cell; 20: auxiliary grid; 30: junction point; 40: welding strip; 50: adhesive point; A: first direction; B: second direction. Specific embodiments

[0027] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] Referring to Figure 1, the photoelectric conversion efficiency corresponding to the cell is shown when there is no main grid on the front side of the half-cell, with the number of welding strips x, the width of the welding strip along the second direction y and the number of auxiliary grids z as variables; Referring to Figure 2, the quantitative relationship between the number of welding strips x, the width of the welding strip along the second direction y and the number of auxiliary grids z is shown when there is no main grid on the front side of the half-cell; Referring to Figure 3, the graphical relationship between the number of welding strips x and the width of the welding strip along the second direction y is shown; Referring to Figure 4, the graphical relationship between the number of welding strips x and the number of auxiliary grids z is shown.

[0029] The present application discloses a battery string, which includes a battery cell 10 without a main grid; multiple auxiliary grids 20, which are arranged at intervals on the surface of the battery cell 10 along a first direction A; multiple welding ribbons 40, which are arranged at intervals along a second direction B and connected to the surface of the battery cell 10, and each welding ribbon 40 is connected to at least a portion of the multiple auxiliary grids 20, and the second direction B is perpendicular to the first direction A; the number of welding ribbons 40 is x, and the width of the welding ribbon 40 along the second direction B is y, satisfying -0.0105x+0.4186≤y≤-0.01x+0.48, where the unit of x is root and the unit of y is mm.

[0030] It should be noted that the cell 10 in the present application has a first end face and a second end face that are opposite to each other. The surface of the cell 10 in the present application can be the first end face of the cell 10 or the second end face of the cell 10. The first end face is the front face of the cell 10, and it can be understood that the first end face is the light-receiving surface of the cell 10. The second end face is the back face of the cell 10, that is, the backlight side of the cell 10.

[0031] The first end face and the second end face of the battery cell 10 are generally rectangular or square. The battery cell 10 also has a first side face and a second side face that are oppositely disposed, and a third side face and a third side face that are oppositely disposed. In the embodiment of the present application, as shown in FIG5 , the direction extending from the first side face to the second side face is set as a first direction A, and the direction extending from the third side face to the fourth side face is set as a second direction B. The second direction B is perpendicular to the first direction A.

[0032] The battery string disclosed in the embodiments of the present application includes a battery cell 10 without a busbar. It is understood that no busbar is provided on the surface of the battery cell 10. The surface of the battery cell 10 is provided with only a secondary grid 20. The secondary grid 20 includes multiple secondary grids 20, which are spaced apart on the surface of the battery cell along a first direction A. Specifically, a metal paste can be printed on the surface of the battery cell 10 by screen printing to form the multiple secondary grids 20.

[0033] It should be noted that the auxiliary grid 20 in the embodiment of the present application is conductive. Therefore, the auxiliary grid 20 can be formed by printing a metal paste on the surface of the cell 10. The metal paste can be silver paste or other metal pastes. The specific material of the metal paste is not particularly limited. In actual use, technicians can select an appropriate metal paste as needed.

[0034] The battery string disclosed in the embodiment of the present application further includes a plurality of welding ribbons 40, which are spaced apart along the second direction B and connected to the surface of the battery cell 10. For example, the welding ribbons 40 can be adhered to the surface of the battery cell 10 using adhesive dots 50, or can be electrically welded to the surface of the battery cell 10 using welding ribbons. In the embodiment of the present application, there are no additional restrictions on the specific method of connecting the welding ribbons 40 to the surface of the battery cell 10. In actual applications, technicians can select an appropriate connection method as needed.

[0035] As shown in FIG. 5 , each welding strip 40 extends along a first direction A, each auxiliary grid 20 extends along a second direction B, and each welding strip 40 is perpendicular to the auxiliary grids 20 and is connected to at least a portion of the auxiliary grids 20 .

[0036] The battery string disclosed in the embodiments of the present application includes a battery cell 10, and a plurality of auxiliary grids 20 spaced apart along a first direction A on the surface of the battery cell 10 to collect the current generated by the battery cell 10 through the plurality of auxiliary grids 20. A plurality of welding ribbons 40 are spaced apart along a second direction B and connected to the surface of the battery cell 10, and each welding ribbon 40 is connected to at least a portion of the plurality of auxiliary grids 20, so that the welding ribbon 40 is electrically connected to the plurality of auxiliary grids 20. Thus, the current collected by the plurality of auxiliary grids 20 can be collected through the welding ribbons 40 to aggregate the current generated by the battery cells.

[0037] FIG1 shows that, taking half a cell as an example, when the number of sub-grids on the back of the cell remains unchanged, that is, when the number of sub-grids on the second end face of the cell remains unchanged, the photoelectric conversion efficiency of the cell is calculated by adjusting the number x of solder strips 40 on the first end face of the cell, the width y of the solder strip 40 along the second direction B and the number z of sub-grids 20, and a reference value of the photoelectric conversion efficiency of the cell is obtained.

[0038] It should be noted that in the field of photovoltaic module technology, the type of cell is usually named after the number of busbars (BBs) on the surface. For example, if a cell has 10 busbars on its surface, it can be named a 10BB cell. In the embodiment of the present application, as shown in Figure 1 as 12BB-58, 12 represents 12 solder ribbons 40 on the surface of the cell, and 58 represents 58 secondary grids 20 on the surface of the cell.

[0039] Taking the 12BB-58 in Figure 1 as an example, 12 solder ribbons 40 are provided on the first end surface of the cell 10, meaning the number x of solder ribbons 40 is 12. Fifty-eight auxiliary grids 20 are provided on the first end surface of the cell 10, meaning the number z of auxiliary grids 20 is 58. When the width y of the solder ribbon 40 along the second direction B is 0.36 mm, the relative photovoltaic efficiency of the cell is taken as a baseline value of 0.000. When the width y of the solder ribbon 40 along the second direction B is 0.35 mm, the relative photovoltaic efficiency of the cell is 0.0003. When the width y of the solder ribbon 40 along the second direction B is 0.34 mm, the relative photovoltaic efficiency of the cell is -0.001. When the width y of the solder ribbon 40 along the second direction B is 0.33 mm, the relative photovoltaic efficiency of the cell is -0.003. When the width y of the solder ribbon 40 along the second direction B is 0.32 mm, the relative photovoltaic conversion efficiency of the cell is -0.007. When the width y of the solder ribbon 40 along the second direction B is 0.31 mm, the relative photovoltaic conversion efficiency of the cell is -0.013. When the width y of the solder ribbon 40 along the second direction B is 0.3 mm, the relative photovoltaic conversion efficiency of the cell is -0.020.

[0040] Based on the above data, when the number x of solder ribbons 40 is 12 and the number z of auxiliary grids 20 is 58, the relative photovoltaic conversion efficiency of the cell is highest when the width y of the solder ribbon 40 along the second direction B is 0.35 mm. Therefore, it can be seen that there is a combination relationship between the number x of solder ribbons 40, the width y of the solder ribbon 40 along the second direction B, and the number z of auxiliary grids 20.

[0041] As shown in FIG2 , when the number x of solder ribbons 40 is 12, the maximum value of the width y of the solder ribbon 40 along the second direction B can be set to 0.36 mm, the minimum value of the width y of the solder ribbon 40 along the second direction B can be set to 0.3 mm, the maximum value of the number z of the auxiliary grids 20 can be set to 66, and the minimum value of the number z of the auxiliary grids 20 can be set to 51. This can improve the photovoltaic conversion efficiency of the solar cell.

[0042] Based on the data shown in Figures 1 and 2 , in the embodiment of the present application, as shown in Figure 3 , the width y of the solder ribbon 40 along the second direction B is set to -0.0105x + 0.4186 ≤ y ≤ -0.01x + 0.48. By adjusting the width y of the solder ribbon 40 along the second direction B for different numbers x of solder ribbons 40 , the photovoltaic conversion efficiency of the cell is improved.

[0043] In the embodiment of the present application, as shown in FIG3 , the width y of the soldering ribbon 40 along the second direction B is set to be greater than or equal to -0.0105x+0.4186 and less than or equal to -0.01x+0.48. In other words, the width y of the soldering ribbon 40 along the second direction B is not only less than or equal to -0.01x+0.48, but also greater than or equal to -0.0105x+0.4186.

[0044] As shown in FIG2 , when the number x of solder ribbons 40 is 12, the width y of the solder ribbon 40 along the second direction B is less than or equal to 0.36 mm and greater than or equal to 0.3 mm. When the number x of solder ribbons 40 is 13, the width y of the solder ribbon 40 along the second direction B is less than or equal to 0.35 mm and greater than or equal to 0.28 mm.

[0045] In the embodiment of the present application, by setting the width y of the soldering ribbon 40 along the second direction B to be greater than or equal to -0.0105x+0.4186 and less than or equal to -0.01x+0.48, the range of the width y of the soldering ribbon 40 along the second direction B is further limited when the number x of soldering ribbons 40 is different, thereby further improving the photovoltaic conversion efficiency of the solar cell.

[0046] As an optional embodiment, as shown in FIG4 , the number of the auxiliary grids 20 is z, satisfying z≤0.0828x 2 -3.7862x+100.26, where x and z are both roots.

[0047] In the embodiment of the present application, as shown in FIG4 , the number z of the auxiliary grids 20 is set to be less than or equal to 0.0828x 2 -3.7862x+100.26. When the number x of the solder ribbons 40 is different, the photoelectric conversion efficiency of the solar cell can be improved by adjusting the number z of the auxiliary grids 20.

[0048] 2 , when the number x of the soldering ribbons 40 is 12, the number z of the auxiliary grids 20 is less than or equal to 66. When the number x of the soldering ribbons 40 is 13, the number z of the auxiliary grids 20 is less than or equal to 64.

[0049] As an optional implementation, as shown in FIG4 , z ≥ 0.1754x 2-7.2048x+115.26.

[0050] In the embodiment of the present application, as shown in FIG4 , the number z of the auxiliary grids 20 is set to be greater than or equal to 0.1754x 2 -7.2048x+115.26. That is to say, the number z of the auxiliary grid 20 must not only be less than or equal to 0.0828x 2 -3.7862x+100.26, and must be greater than or equal to 0.1754x 2 -7.2048x+115.26.

[0051] As shown in FIG2 , when the number x of solder ribbons 40 is 12, the number z of auxiliary grids 20 is less than or equal to 66 and greater than or equal to 51. When the number x of solder ribbons 40 is 13, the number z of auxiliary grids 20 is less than or equal to 64 and greater than or equal to 49.

[0052] In the embodiment of the present application, the number z of the auxiliary grids 20 is set to be greater than or equal to 0.1754x 2 -7.2048x+115.26. In the case of different numbers x of solder ribbons 40, the range of the number z of auxiliary grids 20 is further limited, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0053] Referring to Figure 5, there is shown a structural schematic diagram 1 of the battery cell described in the embodiment of the present application; referring to Figure 6, there is shown a structural schematic diagram 2 of the battery cell described in the embodiment of the present application; referring to Figure 7, there is shown a structural schematic diagram of the joining point described in the embodiment of the present application; referring to Figure 8, there is shown a schematic diagram 1 of the adhesive point described in the embodiment of the present application; referring to Figure 9, there is shown a schematic diagram 2 of the adhesive point described in the embodiment of the present application; referring to Figure 10, there is shown a top view of the battery cell described in the embodiment of the present application.

[0054] In the prior art, the solar cell surface is not provided with a busbar. During the cell lamination process, the poor solderability of the secondary grid 20 paste results in poor ohmic contact between the soldering ribbon 40 and the secondary grid 20. This causes the soldering ribbon 40 to separate from the secondary grid 20, resulting in a decrease in the photovoltaic conversion efficiency of the cell and unsatisfactory cell reliability.

[0055] As shown in FIG. 5 , in the embodiment of the present application, a junction point 30 is provided at the connection between the welding ribbon 40 and the auxiliary grid 20 , wherein the welding ribbon 40 is electrically connected to the auxiliary grid 20 through the junction point 30 .

[0056] In the embodiment of the present application, a junction point 30 is provided at the connection between the soldering ribbon 40 and the auxiliary grid 20, and the soldering ribbon 40 is electrically connected to the auxiliary grid 20 through the junction point 30, so that the auxiliary grid 20 and the soldering ribbon 40 are electrically connected through the junction point 30. This improves the problem of poor ohmic contact between the soldering ribbon 40 and the auxiliary grid 20, improves the photoelectric conversion efficiency of the solar cell, and improves the reliability of the solar cell.

[0057] It should be noted that the junction 30 in the embodiment of the present application is conductive. The junction 30 can be screen-printed on the surface of the battery cell 10 using metal paste. Optionally, the metal paste can be silver paste, which has better conductivity.

[0058] Of course, in addition to silver paste, the metal paste in the embodiment of the present application can also be other metal pastes. Here, there are no excessive restrictions on the specific materials of the metal paste. In actual use, technicians can select appropriate metal paste as needed.

[0059] It should be noted that in the embodiment of the present application, the welding strip 40 can be directly welded to the auxiliary grid 20, or as shown in Figure 7, a joint 30 can be set at the connection between the welding strip 40 and the auxiliary grid 20, and the welding strip 40 can be electrically connected to the auxiliary grid 20 through the joint 30.

[0060] Specifically, as shown in Figure 7, the auxiliary grid 20 at the junction 30 includes two, and the two auxiliary grids 20 are arranged at intervals along the second direction B. Along the direction perpendicular to the plane where the battery cell 10 is located, the projections of the two auxiliary grids 20 at least partially overlap with the junction 30, and the welding ribbon 40 passes between the two auxiliary grids 20 and is electrically connected to the junction 30, so that the welding ribbon 40 is electrically connected to the auxiliary grid 20 through the junction 30.

[0061] In a direction perpendicular to the plane of the cell 10, the projections of the two auxiliary grids 20 at least partially fall within the junction 30 and are electrically connected to the junction 30. In other words, the projections of the two auxiliary grids 20 at least partially overlap with the projection of the junction 30. The soldering ribbon extends along the first direction A and passes between the two auxiliary grids 20, and the soldering ribbon 40 is electrically connected to the junction 30.

[0062] As an optional embodiment, as shown in FIG. 7 , the width of the junction 30 is greater than the width of the secondary gate 20 .

[0063] In the embodiment of the present application, the width of the joint 30 is set to be larger than the width of the auxiliary grid 20 , and the soldering strip 40 is connected to the auxiliary grid 20 through the joint 30 , thereby improving the reliability of the connection between the auxiliary grid 20 and the soldering strip 40 .

[0064] As an optional embodiment, as shown in FIG. 7 , along the second direction B, the joint 30 is narrow at both ends and wide in the middle.

[0065] In the embodiment of the present application, as shown in FIG7 , the width of the center of the junction 30 along the second direction B is greater than the width at both ends of the junction 30. In other words, along the second direction B, the width of the junction 30 is narrower at both ends and wider in the center. In the embodiment of the present application, by increasing the width of the center of the junction 30, the reliability of the connection between the solder ribbon 40 and the junction 30 is improved, thereby improving the photovoltaic conversion efficiency of the cell and improving the reliability of the cell.

[0066] As an optional embodiment, as shown in FIG. 8 and FIG. 9 , along the first direction A, there is a first gap between the two auxiliary grids 20 , and the width of the first gap is greater than the width of the adhesive dot 50 .

[0067] In the embodiment of the present application, as shown in Figures 8 and 9, a first gap exists between two adjacent auxiliary grids 20 along the first direction A, so that the adhesive dots 50 can be disposed between the two adjacent auxiliary grids 20. In the embodiment of the present application, along the first direction A, the width of the first gap between two adjacent solder strips 40 is set to be greater than the width of the adhesive dots 50.

[0068] In the embodiment of the present application, the solder ribbon 40 is bonded to the surface of the cell 10 via adhesive dots 50. The adhesive dots 50 may be made of a shadowless adhesive, also known as a photosensitive adhesive or a UV-curable adhesive. Alternatively, the adhesive dots 50 may be made of a thermosetting adhesive. Of course, other types of adhesive may also be used for the adhesive dots 50. This application does not impose any restrictions on the specific type of adhesive used for the adhesive dots 50. In actual use, technicians can select an appropriate adhesive as needed.

[0069] It should be noted that the adhesive used for the adhesive point 50 is generally an insulating material, and along the first direction A, the width of the first gap between two adjacent solder strips 40 is set to be larger than the width of the adhesive point 50. This allows the adhesive point 50 to be set between two adjacent solder strips 40, avoiding the placement of the adhesive point 50 affecting the reliability of the electrical connection between the solder strips 40 and the auxiliary grid 20.

[0070] As an optional embodiment, each soldering ribbon 40 is connected to the battery cell 10 via a plurality of adhesive spots 50 , and the plurality of adhesive spots 50 are arranged at intervals along the first direction A.

[0071] In the embodiment of the present application, each soldering ribbon 40 is connected to the surface of the battery cell 10 via a plurality of adhesive dots 50 to enhance the reliability of the connection of the soldering ribbon 40. The plurality of adhesive dots 50 are spaced apart along the first direction A, and the soldering ribbon 40 is bonded to the plurality of adhesive dots 50 along the first direction A, so that the soldering ribbon 40 can extend along the first direction A.

[0072] In the embodiment of the present application, as shown in FIG9 , the plurality of adhesive dots 50 corresponding to two adjacent solder strips 40 can be staggered in the second direction B. As shown in FIG8 , the plurality of adhesive dots 50 corresponding to two adjacent solder strips 40 can also be arranged correspondingly in the second direction B. In the embodiment of the present application, there are no excessive restrictions on the specific arrangement of the adhesive dots 50, as long as the width of the first gap between the two adjacent solder strips 40 along the first direction A is set to be greater than the width of the adhesive dots 50.

[0073] As an optional embodiment, at least a portion of the plurality of adhesive dots 50 completely avoids the plurality of auxiliary grids 20 .

[0074] In the embodiment of the present application, at least a portion of the plurality of adhesive dots 50 are completely away from the plurality of auxiliary grids 20 , thereby avoiding as much as possible the arrangement of the adhesive dots 50 affecting the reliability of the electrical connection between the soldering ribbon 40 and the auxiliary grid 20 .

[0075] Of course, as an optional embodiment, at least a portion of the plurality of adhesive dots 50 may be bonded to the plurality of auxiliary grids 20. This allows only a portion of the adhesive dots 50 to be bonded to the auxiliary grid 20, while the remaining portion avoids the auxiliary grid 20, thereby minimizing the effect of the adhesive dots 50 on the reliability of the electrical connection between the soldering ribbon 40 and the auxiliary grid 20.

[0076] As an optional embodiment, the width of the welding ribbon 40 along the second direction B is greater than or equal to 0.19 mm and less than or equal to 0.36 mm.

[0077] In the embodiment of the present application, the width of the soldering ribbon 40 is set to be greater than or equal to 0.19 mm and less than or equal to 0.36 mm along the second direction B. Specifically, the width of the soldering ribbon 40 can be set to 0.19 mm, 0.22 mm, 0.25 mm, 0.28 mm, 0.32 mm, 0.36 mm, etc.

[0078] In the embodiment of the present application, the width of the soldering ribbon 40 is set to be greater than or equal to 0.19 mm and less than or equal to 0.36 mm along the second direction B. While ensuring the current collection capacity of the soldering ribbon 40, the shielding of the soldering ribbon 40 on the surface of the cell is minimized, thereby further improving the photovoltaic conversion efficiency of the cell.

[0079] The present application discloses a battery string comprising: a battery cell without a main grid; a plurality of auxiliary grids spaced apart along a first direction on the surface of the battery cell; a plurality of welding ribbons spaced apart along a second direction and connected to the surface of the battery cell, with each welding ribbon connected to at least a portion of the plurality of auxiliary grids, the second direction being perpendicular to the first direction; the number of welding ribbons being x, the width of the welding ribbons along the second direction being y, such that -0.0105x+0.4186≤y≤-0.01x+0.48, where x is in units of ribbons and y is in units of mm. In the present application, by setting the width y of the welding ribbons along the second direction relative to the number of welding ribbons x so that y is greater than or equal to -0.0105x+0.4186 and less than or equal to -0.01x+0.48, the photovoltaic conversion efficiency of the battery cell can be improved by limiting the range of the welding ribbon width y under different welding ribbon number x.

[0080] An embodiment of the present application further provides a photovoltaic assembly, which includes the battery string described in the above embodiment, wherein the battery string includes a plurality of battery strings, and the plurality of battery strings are arranged at intervals.

[0081] It should be noted that in the embodiment of the present application, the battery string included in the photovoltaic module has the same structure as the battery string described in the above embodiment, and its beneficial effects are also similar, which will not be repeated here.

[0082] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0083] References herein to "one embodiment," "an embodiment," or "one or more embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Furthermore, please note that examples of the phrase "in one embodiment" herein do not necessarily all refer to the same embodiment. In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0084] In the claims, any reference signs placed between brackets shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present application may be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery string, wherein: include: A battery cell without a main grid; A plurality of auxiliary grids, wherein the plurality of auxiliary grids are arranged on the surface of the battery cell at intervals along a first direction; A plurality of welding strips, which are arranged at intervals along a second direction and connected to the surface of the battery cell, and each welding strip is connected to at least a portion of the plurality of auxiliary grids, and the second direction is perpendicular to the first direction; The number of the welding strips is x, the width of the welding strips along the second direction is y, satisfying -0.0105x+0.4186≤y≤-0.01x+0.48, the unit of x is root, and the unit of y is mm.

2. The battery string according to claim 1, wherein: Each of the welding strips is connected to the battery cell via a plurality of adhesive spots, and the plurality of adhesive spots are arranged at intervals along the first direction.

3. The battery string according to claim 2, wherein: The plurality of adhesive spots corresponding to two adjacent welding strips are staggered in the second direction.

4. The battery string according to claim 2, wherein: The plurality of adhesive spots corresponding to two adjacent welding strips are correspondingly arranged in the second direction.

5. The battery string according to claim 2, wherein: At least a portion of the plurality of adhesive dots completely avoids the plurality of auxiliary grids.

6. The battery string according to claim 2, wherein: At least a portion of the plurality of adhesive dots is adhered to the plurality of auxiliary grids.

7. The battery string according to claim 1, wherein: The number of the auxiliary grids is z, satisfying z≤0.0828x 2 -3.7862x+100.26, where z is in roots.

8. The battery string according to claim 7, wherein: Satisfy z ≥ 0.1754x 2 -7.2048x+115.

26.

9. The battery string according to claim 1, wherein: A junction point is provided at a connection between the welding strip and at least a portion of the auxiliary grid, wherein the welding strip is electrically connected to the auxiliary grid through the junction point.

10. The battery string according to claim 9, wherein: The width of the junction point is greater than the width of the secondary gate.

11. The battery string according to claim 10, wherein: Along the second direction, the junction is narrow at both ends and wide in the middle.

12. The battery string according to claim 2, wherein: Along the first direction, there is a first gap between two adjacent auxiliary grids, and the width of the first gap is greater than the width of the adhesive point.

13. A battery string, wherein: include: A battery cell without a main grid; A plurality of auxiliary grids, wherein the plurality of auxiliary grids are arranged on the surface of the battery cell at intervals along a first direction; A plurality of welding strips, which are arranged at intervals along a second direction and connected to the surface of the battery cell, and each welding strip is connected to at least a portion of the plurality of auxiliary grids, and the second direction is perpendicular to the first direction; The number of the welding strips is x, the number of the auxiliary grids is z, and 0.1754x is satisfied. 2 -7.2048x+115.26≤z≤0.0828x 2 -3.7862x+100.26, where x and z are in roots.

14. The battery string according to claim 13, wherein: Each of the welding strips is connected to the battery cell via a plurality of adhesive spots, and the plurality of adhesive spots are arranged at intervals along the first direction.

15. The battery string according to claim 14, wherein: The plurality of adhesive spots corresponding to two adjacent welding strips are staggered in the second direction.

16. The battery string according to claim 14, wherein: The plurality of adhesive spots corresponding to two adjacent welding strips are correspondingly arranged in the second direction.

17. The battery string according to claim 14, wherein: At least a portion of the plurality of adhesive dots completely avoids the plurality of auxiliary grids.

18. The battery string according to claim 14, wherein: At least a portion of the plurality of adhesive dots is adhered to the plurality of auxiliary grids.

19. The battery string according to claim 14, wherein: Along the first direction, there is a first gap between two adjacent auxiliary grids, and the width of the first gap is greater than the width of the adhesive point.

20. The battery string according to claim 13, wherein: The width of the welding strip along the second direction is greater than or equal to 0.19 mm and less than or equal to 0.36 mm.

21. A photovoltaic module, wherein: include: The battery string according to any one of claims 1-20, comprising a plurality of battery strings, wherein the plurality of battery strings are arranged at intervals.

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