Back contact cell string and photovoltaic module

Abstract

The utility model is suitable for the technical field of solar cells, and provides a back contact cell string and a photovoltaic assembly, the back contact cell string comprises a plurality of cells and a plurality of solder strips; the battery piece is provided with a first edge and a second edge which are opposite in the first direction; the distance between the first welding strip closest to the first edge and the first edge is a first distance, the distance between the second welding strip closest to the first edge and the first edge is a second distance, and the first distance is smaller than the second distance; in the two first welding strips adjacent to the second welding strip, the distance between the first welding strip close to the first edge and the second welding strip is a third distance, the distance between the first welding strip close to the second edge and the second welding strip is a fourth distance, and the third distance is smaller than the fourth distance; the distance between every two adjacent first welding strips is 1.9-2.1 times of the first distance. According to the back contact cell string provided by the utility model, all the welding strips can be synchronously placed on the silicon wafer, the cell manufacturing process is simplified, and the production efficiency is improved.

Description

[0001] This application claims priority to patent application No. 2024225060918 (the earlier application was filed on October 16, 2024), entitled "Back Contact Battery and Photovoltaic Module". Technical Field

[0002] This utility model belongs to the field of solar cell technology, and in particular relates to a back-contact battery string and photovoltaic module. Background Technology

[0003] Solar cell power generation is a sustainable and clean energy source that utilizes the photovoltaic effect of semiconductor pn junctions to convert sunlight into electrical energy. In solar cells, back-contact cells are those where both the emitter and base contact electrodes are placed on the back of the cell (the non-light-receiving surface). Since the light-receiving surface of this cell is not obstructed by any metal electrodes, this effectively increases the short-circuit current of the silicon wafer.

[0004] To achieve series connection of silicon wafers, the back of the back contact cell is provided with two types of sub-gates of different polarities. In related technologies, the spacing of all sub-gates is equal and the width of the sub-gates is relatively narrow. The tool for fixing the solder ribbons needs to perform multiple gripping operations to fix all the solder ribbons, which is cumbersome and time-consuming. Utility Model Content

[0005] This utility model provides a back-contact battery string and a photovoltaic module, aiming to solve the problem of cumbersome and time-consuming fixed welding strip operation.

[0006] This utility model provides a back-contact battery string, comprising: multiple battery cells and multiple solder strips; the solder strips connect two adjacent battery cells;

[0007] The welding strip includes a first welding strip and a second welding strip; the first welding strip and the second welding strip are disposed on the battery cell, extending along a second direction and alternately arranged along a first direction;

[0008] The spacing between two adjacent first weld strips is equal to the spacing between two adjacent second weld strips;

[0009] The battery cell has a first edge and a second edge opposite to each other in the first direction;

[0010] The distance between the first solder strip closest to the first edge and the first edge is the first distance, and the distance between the second solder strip closest to the first edge and the first edge is the second distance, wherein the first distance is smaller than the second distance;

[0011] In the two first solder strips adjacent to the second solder strip, the distance between the first solder strip closer to the first edge and the second solder strip is the third distance, and the distance between the first solder strip closer to the second edge and the second solder strip is the fourth distance, wherein the third distance is smaller than the fourth distance;

[0012] The spacing between two adjacent first solder strips is 1.9 to 2.1 times the first spacing.

[0013] In some embodiments, the spacing between two adjacent first solder strips is twice the first spacing.

[0014] In some embodiments, the difference between the spacing between two adjacent first solder strips and the first spacing is within a first range, wherein the first range is greater than or equal to 4.5 mm and less than the first spacing.

[0015] In some embodiments, the spacing between two adjacent second solder strips is 0.9 to 1.1 times the second spacing.

[0016] In some embodiments, the difference between the spacing between two adjacent second solder strips and the second spacing is within a second range, the second range being greater than 0 mm and less than or equal to 2.6 mm.

[0017] In some embodiments, the spacing between two adjacent first solder strips is 17.5mm to 18.5mm, the first spacing is 9.3mm to 10.3mm, and the second spacing is 15mm to 16.2mm.

[0018] In some embodiments, the line width of the first solder strip is 2mm to 3mm.

[0019] In some embodiments, the distance between the second solder strip closest to the second edge and the second edge is a fifth distance, which is equal to the first distance.

[0020] This utility model also provides a photovoltaic module, including: a back contact battery string as described in any of the preceding claims.

[0021] The back-contact battery string and photovoltaic module provided by this utility model have an asymmetrical design for the solder ribbon spacing, which makes it easy to adapt to different solder ribbon fixing tools. Due to the larger fourth spacing, the solder ribbon fixing tool has more placement space, which allows multiple sets of solder ribbons to be operated at the same time. All solder ribbons can be placed on the silicon wafer synchronously, which simplifies the battery manufacturing process and improves production efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the back contact battery string provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the photovoltaic module provided in this embodiment of the utility model. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0025] In this invention, the reference to "embodiment" or "implementation" means that a specific feature, component, or characteristic described in connection with an embodiment or implementation may be included in at least one embodiment of this invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] In the description of this utility model, it should be understood that the terms "length," "width," "upper," "lower," "left," "right," "horizontal," "top," and "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model 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 utility model. 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 indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] The following is combined with Figures 1 to 2 The back contact battery and photovoltaic module provided by the present invention will be described in detail through specific embodiments and application scenarios.

[0029] Figure 1 This is a schematic diagram of the back contact battery provided in an embodiment of the present invention.

[0030] like Figure 1 As shown, this utility model provides a back contact battery, including: a silicon wafer 10, a first sub-grid 20, a second sub-grid 30, a first solder strip 40 and a second solder strip 50, wherein the first sub-grid 20 and the second sub-grid 30 have different polarities;

[0031] The first sub-gate 20 and the second sub-gate 30 are disposed on the back side of the silicon wafer 10 and extend along the first direction. The first sub-gate 20 and the second sub-gate 30 are arranged alternately along the second direction, and the first direction and the second direction intersect.

[0032] The first solder strip 40 and the second solder strip 50 extend along the second direction and are alternately arranged along the first direction. The first solder strip 40 is used to collect the current generated by the first sub-gate 20, and the second solder strip 50 is used to collect the current generated by the second sub-gate 30. The number of the first solder strip 40 and the second solder strip 50 is equal.

[0033] The spacing between two adjacent first weld strips 40 is equal to the spacing between two adjacent second weld strips 50;

[0034] The silicon wafer 10 has opposing first and second edges in a first direction;

[0035] The distance between the first solder strip 40, which is closest to the first edge, and the first edge is the first distance D1, and the distance between the second solder strip 50, which is closest to the first edge, and the first edge is the second distance D2. The first distance D1 is smaller than the second distance D2.

[0036] In the two adjacent first weld strips 40 of the second weld strip 50, the distance between the first weld strip 40 near the first edge and the second weld strip 50 is the third distance D3, and the distance between the first weld strip 40 near the second edge and the second weld strip 50 is the fourth distance D4. The third distance D3 is smaller than the fourth distance D4.

[0037] All first solder strips 40 and all second solder strips 50 are placed synchronously on silicon wafer 10.

[0038] It is understood that the back contact battery string includes multiple battery cells. This embodiment of the invention describes the structure of one of the battery cells; the structures of the other battery cells may be the same or different, and are not specifically limited here. In this embodiment, the battery cell is a gridless battery cell.

[0039] Reference Figure 1 The gridless solar cell includes a silicon wafer 10, a number of first sub-grids 20, a number of second sub-grids 30, a number of first solder strips 40 and a number of second solder strips 50.

[0040] The silicon wafer 10 serves as the main body of the solar cell and is used for photoelectric conversion. The silicon wafer 10 has a front side and a back side. A plurality of first sub-gates 20, a plurality of second sub-gates 30, a plurality of first solder ribbons 40 and a plurality of second solder ribbons 50 are all disposed on the back side of the silicon wafer 10.

[0041] A plurality of first sub-gates 20 and a plurality of second sub-gates 30 extend along a first direction and are arranged alternately and at equal intervals along a second direction to ensure uniform current distribution for easy current collection. The sub-gates on the silicon wafer 10 are distributed as follows: first sub-gate 20, second sub-gate 30, first sub-gate 20, second sub-gate 30, ... first sub-gate 20, second sub-gate 30.

[0042] The first sub-gate 20 and the second sub-gate 30 have opposite polarities; one of them is a positive sub-gate, and the other is a negative sub-gate. The first sub-gate 20 and the second sub-gate 30 are used to collect and conduct current.

[0043] A plurality of first solder strips 40 and a plurality of second solder strips 50 extend along a second direction and are arranged alternately in parallel along a first direction. The silicon wafer 10 has opposing first and second edges in the first direction. Since the first spacing D1 is smaller than the second spacing D2, the solder strips closest to the first edge are the first solder strips 40. The solder strips on the silicon wafer 10 are distributed as follows: first solder strip 40, second solder strip 50, first solder strip 40, second solder strip 50, ..., first solder strip 40, second solder strip 50. Wherein, the first spacing D1 can be the distance between the centerline of the first solder strip 40 closest to the first edge in the second direction and the first edge, and the second spacing D2 can be the distance between the centerline of the second solder strip 50 closest to the first edge in the second direction and the first edge.

[0044] It should be noted that the first solder strip 40 is electrically connected to the first sub-gate 20, and the first solder strip 40 is insulated from the second sub-gate 30; the second solder strip 50 is electrically connected to the second sub-gate 30, and the second solder strip 50 is insulated from the first sub-gate 20. The insulation can be achieved by applying insulating adhesive at the connection between the first solder strip 40 and the second sub-gate 30, or by applying insulating adhesive at the connection between the second solder strip 50 and the first sub-gate 20. Other insulating layers or materials can also be used to achieve insulation between sub-gates and solder strips of different polarities; no specific limitations are specified here.

[0045] The first solder strip 40 is used to collect the current generated by the first sub-busbar 20, and the second solder strip 50 is used to collect the current generated by the second sub-busbar 30 and conduct the collected current out of the cell. This arrangement allows each solder strip to effectively collect the current of the corresponding polarity sub-busbar. Figure 1The solder strips shown are for illustrative purposes only and do not represent all solder strips. Solder strips are also provided in the middle area, but they have been omitted for clarity.

[0046] The number of first sub-gates 20 and second sub-gates 30 is equal, and the number of first solder strips 40 and second solder strips 50 is equal, ensuring the balance of current collection.

[0047] It should be noted that, preferably, the first direction is the horizontal direction, which is also the width direction of the solar cell; the second direction is the vertical direction, which is also the length direction of the solar cell.

[0048] It is understandable that the spacing between two adjacent first solder strips 40 is the third spacing D3 + the fourth spacing D4, and the spacing between two adjacent second solder strips 50 is also the third spacing D3 + the fourth spacing D4. That is, the spacing between the positive electrode sub-gate and the spacing between the negative electrode sub-gate are equal, which can ensure the balance of current collection.

[0049] The first solder strip 40 and the second solder strip 50 are not equidistantly distributed. Assuming that two adjacent solder strips of different polarities form a group, the distance between two solder strips in the same group is the third distance D3, and the distance between adjacent groups of solder strips is the fourth distance D4, with the third distance D3 being smaller than the fourth distance D4. The size of the third distance D3 matches the solder strip fixing tool for fixing one group of solder strips. If the third distance D3 is equal to the fourth distance D4 of the adjacent group of solder strips, then the fourth distance D4 is insufficient to accommodate two groups of solder strip gripping tools, thus preventing the simultaneous fixing of multiple groups of solder strips. Therefore, the fourth distance D4 is widened to be larger than the third distance D3, allowing the fourth distance D4 to accommodate two groups of solder strip gripping tools.

[0050] Optionally, the third spacing D3 and the fourth spacing D4 can be widened simultaneously to achieve the simultaneous fixation of multiple sets of welding strips.

[0051] It should be noted that, among the two adjacent first solder strips 40 of the second solder strip 50, the third spacing D3 can be the distance between the center line of the first solder strip 40 near the first edge in the second direction and the center line of the second solder strip 50 in the second direction, and the fourth spacing D4 can be the distance between the center line of the first solder strip 40 near the second edge in the second direction and the center line of the second solder strip 50 in the second direction.

[0052] The back contact battery provided in this embodiment of the utility model has an asymmetrical design for the solder ribbon spacing, which is convenient to adapt to different solder ribbon fixing tools. Due to the larger fourth spacing, the solder ribbon fixing tool has more placement space, and multiple sets of solder ribbons can be operated at the same time. All solder ribbons can be placed synchronously on the silicon wafer, which simplifies the battery manufacturing process, improves production efficiency, and allows for the placement of wider solder ribbons, which can collect current more effectively.

[0053] In some embodiments, the spacing between two adjacent first solder strips 40 is greater than a first spacing D1, and the difference between the spacing between two adjacent first solder strips 40 and the first spacing D1 is within a first range, the first range being determined based on the magnitude of the current collected to the first solder strip 40 closest to the first edge.

[0054] It is understood that the solder strip closest to the first edge is the first solder strip 40, and the solder strip closest to the second edge is the second solder strip 50. In actual implementation, the distance between the edge solder strips can be adjusted based on the current-gathering effect of the solder strips closest to the first and second edges to optimize the current-gathering effect. Therefore, the spacing between two adjacent first solder strips 40 is a variable range value, which can be adjusted according to the actual situation.

[0055] It should be noted that the first solder strip 40 closest to the first edge is connected to the first sub-gate 20 on both sides in the first direction. The current transmission direction of the first sub-gate 20 on the side closer to the first edge is from the end closer to the edge to the connection between the first solder strip 40 and the first sub-gate 20. The current transmission direction of the first sub-gate 20 on the side farther from the first edge is from the first sub-gate 20 to the two first solder strips 20 respectively. The two first solder strips 20 are the first solder strip 40 closest to the first edge and its adjacent first solder strip 40.

[0056] Therefore, when the first sub-gate 20 transmits current to the first solder strip 40 closest to the first edge and its adjacent first solder strip 40, if the current magnitude is not uniformly distributed, the current collection effect of the first solder strip 40 closest to the first edge will be poor; if the current magnitude is uniformly distributed, the current collection effect of the first solder strip 40 closest to the first edge will be better.

[0057] In some embodiments, the spacing between two adjacent first solder strips 40 is twice the first spacing D1.

[0058] In actual implementation, except for the first solder strip 40 closest to the first edge and the first solder strip 40 closest to the second edge, all other first solder strips 40 are first solder strips 40 in the middle area.

[0059] The distance between the first solder strip 40 closest to the second edge and the second edge is equal to the spacing between two adjacent first solder strips 40.

[0060] Each of the first solder strips 40 in the middle region has two adjacent solder strips. Therefore, the carriers collected on the sub-gate connected to the first solder strip 40 in the middle region can flow to the two first solder strips 40. This can be understood as the carrier transmission distance being half the distance between the two adjacent first solder strips 40. Therefore, to ensure the current collection effect, the distance between the two adjacent first solder strips 40 is set to twice the first distance D1. This ensures that the transmission distance of carriers on the first sub-gate 20 near the edge to the first solder strip 40 closest to the first edge is equal to the transmission distance of carriers on the first sub-gate 20 far from the edge to the first solder strip 40 not near the edge.

[0061] In some embodiments, the first range is greater than or equal to 4.5 mm and less than the first spacing D1.

[0062] In practice, the first range is used to ensure that the spacing between two adjacent first solder strips 40 is approximately twice the first spacing D1. For example, the first range is between 4.5mm and the first spacing D1, where the first spacing D1 is greater than 4.5mm.

[0063] In some embodiments, the second difference between the spacing of two adjacent second solder strips 50 and the second spacing D2 is within a second range, the second range being determined based on the second spacing D2.

[0064] It is understandable that the distance between the second solder strip 50 closest to the first edge and the first edge is the second distance D2. Therefore, the solder strip closest to the first edge is not the second solder strip 50. Thus, the distance between two adjacent second solder strips 50 and the second difference between the second distance D2 can be approximately equal.

[0065] In some embodiments, the second range is greater than or equal to 0 mm and less than or equal to 2.6 mm.

[0066] In actual implementation, the second range is between 0mm and 2.6mm. For example, it can be any value between 0.5mm, 0.8mm, 1.5mm, 2.0mm, 2.5mm, 2.6mm or 0mm and 2.6mm. No specific restrictions are imposed here.

[0067] In some embodiments, the spacing between two adjacent first solder strips 40 is 17.5mm to 18.5mm, the first spacing D1 is 9.3mm to 10.3mm, and the second spacing D2 is 15mm to 16.2mm.

[0068] In practice, the width of the solar cell is any width between 182.1 mm and 182.9 mm, or any width between 210.1 mm and 210.9 mm. For example, it can be 182.1 mm, 182.2 mm, 182.3 mm, 182.4 mm, 182.5 mm, 182.6 mm, 182.7 mm, 182.8 mm, or 182.9 mm, etc.; it can also be 210.1 mm, 210.2 mm, 210.3 mm, 210.4 mm, 210.5 mm, 210.6 mm, 210.7 mm, 210.8 mm, or 210.9 mm.

[0069] For example: the width of the solar cell is 182.7mm, the spacing between two adjacent first solder strips is 17.6mm, the first spacing D1 is 9.3mm, and the second spacing D2 is 15mm;

[0070] Alternatively, the cell width is 210.9mm, the spacing between two adjacent first solder strips is 10mm, the first spacing D1 is 10.15mm, and the second spacing D2 is 16mm.

[0071] Understandably, the first spacing D1 and the second spacing D2 can be adaptively adjusted according to different cell widths.

[0072] In some embodiments, the line width of the first solder strip 40 is 2mm to 3mm.

[0073] In practice, the linewidth of the solder strip directly affects its current transmission capability. A wider linewidth results in lower resistance and higher current transmission efficiency. Because the solder strip spacing in this embodiment is non-equidistant, the solder strip layout is more flexible and space is less restricted, allowing for the placement of 2mm to 3mm solder strips. For example, it can be any linewidth from 2mm to 3mm.

[0074] In some embodiments, the first spacing D1 is equal to the fifth spacing D5, where the fifth spacing D5 is the spacing between the second solder strip 50, which is closest to the second edge, and the second edge.

[0075] It is understandable that the first spacing D1 and the fifth spacing D5 are equal, which makes the cell design more aesthetically pleasing, ensures the uniform distribution and effective transmission of current at the edge of the cell, reduces the concentration and loss of current at the edge of the cell, and improves the overall performance of the cell.

[0076] The fifth spacing D5 can be the distance between the center line of the second weld strip 50, which is closest to the second edge, and the second edge in the second direction.

[0077] The photovoltaic module provided by this utility model has an asymmetrical design for the solder ribbon spacing, which makes it easy to adapt to different solder ribbon fixing tools. Due to the larger fourth spacing, the solder ribbon fixing tool has more placement space, which allows multiple sets of solder ribbons to be operated at the same time. All solder ribbons can be placed on the silicon wafer synchronously, which simplifies the battery manufacturing process and improves production efficiency.

[0078] Figure 2 This is a schematic diagram of the structure of the photovoltaic module provided in this embodiment of the utility model.

[0079] like Figure 2 As shown, this utility model embodiment provides a photovoltaic module 100, including the back contact battery 101 as in any of the above embodiments.

[0080] It should be noted that the back contact battery 101 has been described in detail in the above embodiments, and will not be repeated here.

[0081] The photovoltaic module provided in this embodiment of the utility model has an asymmetrical design for the solder ribbon spacing, which is convenient to adapt to different solder ribbon fixing tools. Due to the larger fourth spacing, the solder ribbon fixing tool has more placement space, and multiple sets of solder ribbons can be operated at the same time. All solder ribbons can be placed on the silicon wafer synchronously, which simplifies the battery manufacturing process, improves production efficiency, and allows for the placement of wider solder ribbons, which can collect current more effectively.

[0082] It is understood that those skilled in the art can combine various implementation methods in the above embodiments under the guidance of the above examples to obtain technical solutions with multiple implementation methods.

[0083] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A back-contact battery string, characterized in that, include: Multiple solar cells and multiple solder strips; the solder strips connect two adjacent solar cells; The welding strip includes a first welding strip and a second welding strip; the first welding strip and the second welding strip are disposed on the battery cell, extending along a second direction and alternately arranged along a first direction; The spacing between two adjacent first weld strips is equal to the spacing between two adjacent second weld strips; The battery cell has a first edge and a second edge opposite to each other in the first direction; The distance between the first solder strip closest to the first edge and the first edge is the first distance, and the distance between the second solder strip closest to the first edge and the first edge is the second distance, wherein the first distance is less than the second distance; In the two first solder strips adjacent to the second solder strip, the distance between the first solder strip closer to the first edge and the second solder strip is the third distance, and the distance between the first solder strip closer to the second edge and the second solder strip is the fourth distance, wherein the third distance is smaller than the fourth distance; The spacing between two adjacent first solder strips is 1.9 to 2.1 times the first spacing.

2. The back contact battery string according to claim 1, characterized in that, The spacing between two adjacent first solder strips is twice the first spacing.

3. The back contact battery string according to claim 1, characterized in that, The difference between the spacing between two adjacent first solder strips and the first spacing is within a first range, which is greater than or equal to 4.5 mm and less than the first spacing.

4. The back contact battery string according to claim 1, characterized in that, The spacing between two adjacent second solder strips is 0.9 to 1.1 times the second spacing.

5. The back contact battery string according to claim 4, characterized in that, The difference between the spacing of two adjacent second solder strips and the second spacing is within a second range, which is greater than 0 mm and less than or equal to 2.6 mm.

6. The back contact battery string according to any one of claims 1-5, characterized in that, The spacing between two adjacent first solder strips is 17.5mm~18.5mm, the first spacing is 9.3mm~10.3mm, and the second spacing is 15mm~16.2mm.

7. The back contact battery string according to any one of claims 1-5, characterized in that, The line width of the first solder strip is 2mm~3mm.

8. The back contact battery string according to any one of claims 1-5, characterized in that, The distance between the second solder strip closest to the second edge and the second edge is the fifth distance, which is equal to the first distance.

9. A photovoltaic module, characterized in that, include: The back contact battery string according to any one of claims 1-8.

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