Back-contact stacked photovoltaic modules and photovoltaic systems

Abstract

This application relates to the field of photovoltaic technology and provides a back-contact stacked grid photovoltaic module and photovoltaic system, including a solar cell and a plurality of first fine grids and a plurality of second fine grids alternately arranged on the solar cell along a first direction, wherein the polarities of the first fine grids and the second fine grids are opposite; a plurality of first solder strips are arranged one-to-one on the plurality of first fine grids, and a plurality of second solder strips are arranged one-to-one on the plurality of second fine grids. This application arranges the solder strips and fine grids in the same direction, with the extension direction of the solder strips and fine grids being consistent, forming a full contact surface between the solder strips and fine grids. The solder strips are firmly welded, resulting in high current collection efficiency. Furthermore, because the solder strips and fine grids are arranged correspondingly, the risk of short circuits caused by overlapping of opposite polarity solder strips is reduced. The solder strips are connected to the busbar to form a solder strip mesh structure, which allows multiple solder strips to be aligned with multiple fine grids at the same time, reducing the difficulty of positioning the solder strips.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, and in particular relates to a back-contact stacked-grid photovoltaic module and photovoltaic system. Background Technology

[0002] To reduce the amount of paste used on the grid lines of solar cells, the main grid lines can be eliminated, leaving only the fine grid lines. The solder ribbon collects current directly from the fine grid lines. However, because the fine grid lines are very narrow and densely distributed to improve current collection efficiency, welding the solder ribbon to the fine grid lines in the traditional cross-grid structure can easily lead to overlap of opposite polarity solder ribbons, causing short circuits in the module. Furthermore, due to the small contact area between the solder ribbon and the fine grid lines, the solder ribbon is also prone to detachment, resulting in decreased current collection efficiency and power loss in the photovoltaic module. Utility Model Content

[0003] This application provides a back-contact stacked grid photovoltaic module, which aims to solve the problems of traditional structures with cross-arranged solder strips and fine grids, which are prone to short circuits caused by overlapping of opposite polarity solder strips. Due to the small contact area between the solder strip and the fine grid lines, the solder strip is also easy to detach, resulting in a decrease in current collection efficiency and power loss of the photovoltaic module.

[0004] This application is implemented as follows: a back-contact stacked-grid photovoltaic module includes a solar cell and a plurality of first fine grids and a plurality of second fine grids alternately disposed on the solar cell along a first direction, the first fine grids and the second fine grids having opposite polarities; a plurality of first solder strips disposed one-to-one on the plurality of first fine grids, and a plurality of second solder strips disposed one-to-one on the plurality of second fine grids, the first solder strips, the second solder strips, the first fine grids and the second fine grids respectively extending along a second direction; a first busbar extending along the first direction, the plurality of first solder strips being connected to the first busbar; and a second busbar extending along the first direction, the plurality of second solder strips being connected to the second busbar; wherein the plurality of first solder strips are respectively insulated from the second busbar, and the plurality of second solder strips are respectively insulated from the first busbar.

[0005] Optionally, a plurality of the first solder strips are respectively spaced apart from the second busbar.

[0006] Optionally, a plurality of the second welding strips are respectively spaced apart from the first busbar.

[0007] Optionally, the distance between the first welding strip and the second busbar is 1 to 10 mm, and / or the distance between the second welding strip and the first busbar is 1 to 10 mm.

[0008] Optionally, the first weld strip is one of a round weld strip, a triangular weld strip, or a flat weld strip, and / or the second weld strip is one of a round weld strip, a triangular weld strip, or a flat weld strip.

[0009] Optionally, it also includes a fixing strap extending along the first direction, the fixing strap being used to fix a plurality of first solder strips and a plurality of second solder strips.

[0010] Optionally, there are multiple fixing straps, and the multiple fixing straps are distributed at intervals along the second direction.

[0011] Optionally, the diameter of the first welding strip is in the range of 0.05 to 0.2 mm, and the diameter of the first busbar is in the range of 0.05 to 5 mm.

[0012] Optionally, the diameter of the second welding strip is in the range of 0.05 to 0.2 mm, and the diameter of the second manifold is in the range of 0.05 to 5 mm.

[0013] Optionally, the cross-section of the first busbar is one of a circle, a triangle, or a rectangle, and / or the cross-section of the second busbar is one of a circle, a triangle, or a rectangle.

[0014] Optionally, the back-contact stacked-grid photovoltaic module further includes a first interconnect grid line, and each of the plurality of first fine grids is connected to the first interconnect grid line.

[0015] Optionally, the back-contact stacked-grid photovoltaic module further includes a second interconnect grid line, with each of the plurality of second fine grids connected to the second interconnect grid line.

[0016] Optionally, the first interconnect gate line and the second interconnect gate line extend along the first direction, the first interconnect gate line and the second interconnect gate line are disposed opposite each other in the second direction, and the first interconnect gate line and the second interconnect gate line are parallel to each other.

[0017] This application arranges the solder strip and the fine grid in the same direction, with the extension directions of the solder strip and the fine grid being consistent. The solder strip and the fine grid form a full contact surface, resulting in a strong weld and high busbar efficiency. Furthermore, because the solder strip and the fine grid are arranged correspondingly, the risk of short circuits caused by overlapping of opposite polarity solder strips is reduced. The solder strip and the busbar are connected to form a solder strip mesh structure, which can align multiple solder strips and multiple fine grids at the same time, reducing the difficulty of positioning the solder strip. Attached Figure Description

[0018] Figure 1 This is a structural schematic diagram of the first type of back-contact stacked-grid photovoltaic module provided in the current application;

[0019] Figure 2This is a structural schematic diagram of the second type of back-contact stacked-grid photovoltaic module provided in the current application.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100. Battery cell; 101. Fixing strip; 200. First grid; 300. Second grid; 400. First welding strip; 500. Second welding strip; 600. First busbar; 700. Second busbar; 800. First interconnect grid line; 900. Second interconnect grid line. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0023] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0028] like Figure 1 and Figure 2 As shown in the embodiments of this application, a back-contact stacked-grid photovoltaic module includes a solar cell 100 and a plurality of first fine grids 200 and a plurality of second fine grids 300 alternately disposed along a first direction on the solar cell 100. The polarities of the first fine grids 200 and the second fine grids 300 are opposite. Specifically, the solar cell 100 can be made of semiconductor material. The back side of the solar cell 100 is precisely patterned to form alternating P-type doped regions and N-type doped regions through a doping process, such as laser doping, photomask lithography, or ion implantation. The positions of the doped regions correspond to printed / electroplated fine grid lines. The fine grid lines include positive fine grid lines and negative fine grid lines. The positive fine grid lines form contact with the P-type doped regions, and the negative fine grid lines form contact with the N-type doped regions. The positive and negative fine grid lines are spaced apart to insulate the dissimilar fine grid lines. It is understood that in other embodiments of this application, the structure of the solar cell 100 can also be configured in other ways, which are not limited here. However, it should be noted that in any type of solar cell 100, it is configured to have fine positive grid lines in the P-type doped region and fine negative grid lines in the N-type doped region.

[0029] Specifically, the first fine grid 200 can be a positive electrode fine grid, and the second fine grid 300 can be a negative electrode fine grid. Of course, in other embodiments, the first fine grid 200 can also be a negative electrode fine grid, and the second fine grid 300 can be a positive electrode fine grid. The polarity of the fine grid is determined according to the type of doped region it is configured with. Multiple first fine grids 200 and multiple second fine grids 300 are alternately arranged on the solar cell 100, that is, the polarity of each pair of adjacent fine grids is opposite. Such electrode pattern arrangement is beneficial to the uniform distribution of current on the solar cell 100.

[0030] The solar cell 100 can be substantially rectangular, such as a square, or another type of rectangle, and can have standard corners, cut corners, or rounded corners, depending on actual production needs, and is not specifically limited here. Meanwhile, the number of positive and negative electrode fine grid lines is determined based on the actual size of the solar cell 100, the width of the positive electrode fine grid lines, and the distance between them, and is not specifically limited here.

[0031] Generally, the solar cell 100 has a sheet-like structure. The side that can absorb light energy and convert it into electrical energy is called the light-absorbing side or the front side, and the other side is called the back side. A solar cell with electrodes of both polarities disposed on the back side of the cell is a back-contact cell. In the embodiments of this application, when the solar cell 100 is installed in normal use, the side facing upwards is called the front side, and the side opposite to the front side is called the back side.

[0032] Furthermore, multiple first solder strips 400 are correspondingly disposed on multiple first fine gates 200, and multiple second solder strips 500 are correspondingly disposed on multiple second fine gates 300. The first solder strips 400, second solder strips 500, first fine gates 200, and second fine gates 300 extend along a second direction, that is, in the embodiments of this application, the first solder strips 400, second solder strips 500, first fine gates 200, and second fine gates 300 are arranged in the same direction, wherein the first solder strips 400 and the first... The fine grid 200 forms a full contact surface, and the second solder strip 500 and the second fine grid 300 form a full contact surface. On the one hand, this strengthens the connection between the solder strip and the fine grid. On the other hand, the same solder strip only conducts current on the same fine grid, forming a uniform electric field distribution on the cell 100. Compared with the traditional electrode connection structure, where all fine grids are connected to the same polarity solder strip, it is easy to cause the electric field to concentrate at the edge of the cell 100. In this application, the solder strip and fine grid are set in a one-to-one correspondence, which can eliminate the concentration of reverse bias voltage at the edge of the cell.

[0033] In some embodiments, the first bus 600 extends along a first direction, and a plurality of first solder strips 400 are connected to the first bus 600. Since the first solder strips 400 extend along a second direction, the first solder strips 400 and the first bus 600 are cross-connected, and the plurality of first solder strips 400 and the first bus 600 are connected to form a first solder strip sub-network structure. The second bus 700 extends along the first direction, and since the second solder strips 500 extend along the second direction, a plurality of second solder strips 500 are connected to the second bus 700, and the plurality of second solder strips 500 and the second bus 700 are connected to form a second solder strip sub-network structure. In this way, the first solder strip sub-network is connected to all the positive electrode fine grids, and the second solder strip sub-network is connected to all the negative electrode fine grids, realizing independent current collection for the positive and negative fine grids.

[0034] In this embodiment of the application, for example, the first direction may be the length direction of the battery cell 100, and the second direction may be the width direction of the battery cell 100. The first direction and the second direction are perpendicular to each other.

[0035] Understandably, since the fine gate properties of the first solder ribbon 400 and the second solder ribbon 500 are opposite, the first solder ribbon subnet and the second solder ribbon subnet need to be insulated from each other. Specifically, since the solder ribbons are spaced apart, insulation design is required between the intersecting solder ribbons and the busbar. Therefore, multiple first solder ribbons 400 are insulated from the second busbar 700. For example, multiple first solder ribbons 400 are spaced apart from the second busbar 700. Specifically, a laser can be used to break the ends of the first solder ribbons 400 to form the gap with the second busbar 700. Multiple second solder ribbons 500 are insulated from the first busbar 600. For example, multiple second solder ribbons 500 are spaced apart from the first busbar 600. Specifically, a laser can be used to break the ends of the second solder ribbons 500 to form the gap with the first busbar 600. Thus, the first and second welding strip subnets form an interdigitated structure, and the first and second welding strip subnets do not contact each other, forming a complete physical isolation and completely eliminating short circuits caused by overlapping of dissimilar welding strips.

[0036] Furthermore, the distance between the first solder strip 400 and the second busbar 700 is 1–10 mm, and / or the distance between the second solder strip 500 and the first busbar 600 is 1–10 mm. The distance between the solder strip and the busbar within the above range can achieve complete physical isolation between the solder strip and the busbar, avoiding the possibility of contact between the solder strip and a busbar of opposite polarity.

[0037] In some embodiments, the first welding strip 400 is one of a round welding strip, a triangular welding strip, or a flat welding strip, and / or, the second welding strip 500 is one of a round welding strip, a triangular welding strip, or a flat welding strip. The specific selection of the welding strip shape can be determined according to the production process requirements, and this application does not limit it in this regard.

[0038] In this embodiment, the battery assembly further includes a fixing strip 101 extending along a first direction. The fixing strip 101 is used to fix a plurality of first welding strips 400 and a plurality of second welding strips 500. Specifically, the fixing strip 101 can be a fixing tape, such as UV adhesive, UV thermosetting adhesive, pressure-sensitive adhesive, etc. The fixing strip 101 covers the first welding strips 400 and the second welding strips 500 and bonds them to the battery cell 100, achieving pre-fixation of the welding strips. Subsequently, lamination welding is performed on the welding strips to further weld and fix them to the battery cell 100. It can be understood that there can be multiple fixing strips 101, which are spaced apart along the second direction. The number of fixing strips 101 can be determined according to the size of the battery cell 100 and the production process requirements. For example, four fixing strips can be set at intervals on the battery cell 100 in the second direction to fix the first welding strips 400 and the second welding strips 500.

[0039] In some embodiments, the diameter of the first solder strip 400 ranges from 0.05 to 0.2 mm. For example, the diameter of the first solder strip 400 can be any value between 0.05 mm, 0.1 mm, 0.2 mm, or 0.05 mm and 0.2 mm, and this application does not impose any limitation thereon. The diameter of the first bus 600 ranges from 0.05 to 5 mm. For example, the diameter of the first bus 600 can be any value between 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, or 0.05 mm and 0.5 mm, and this application does not impose any limitation thereon. In other embodiments, the diameter of the first bus 600 is larger than the diameter of the first solder strip 400, thereby reducing resistance loss during the busing process.

[0040] In some embodiments, the diameter of the second solder strip 500 ranges from 0.05 to 0.2 mm. For example, the diameter of the second solder strip 500 can be any value between 0.05 mm, 0.1 mm, 0.2 mm, or 0.05 mm and 0.2 mm, and this application does not impose any limitation thereon. The diameter of the second bus 700 ranges from 0.05 to 5 mm. For example, the diameter of the second bus 700 can be any value between 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, or 0.05 mm and 0.5 mm, and this application does not impose any limitation thereon. In other embodiments, the diameter of the second bus 700 is larger than the diameter of the second solder strip 500, thereby reducing resistance loss during the busing process.

[0041] In some embodiments, the cross-section of the first busbar 600 is one of a circle, a triangle, or a rectangle, and / or the cross-section of the second busbar 700 is one of a circle, a triangle, or a rectangle. The specific selection of the busbar shape can be determined according to the requirements of the production process, and this application does not limit it in this regard.

[0042] The back-contact tandem photovoltaic module also includes a first interconnect grid line 800, with each of the multiple first fine grids 200 connected to the first interconnect grid line 800. By setting the first interconnect grid line 800, the current on the multiple first fine grids 200 is combined, shortening the current transmission path. Furthermore, the first interconnect grid line 800 connects multiple first fine grids 200 in parallel, which can balance the current density of each first fine grid 200 and avoid local overheating. When a single first fine grid 200 fails, the first interconnect grid line 800 provides a bypass channel, reducing the risk of hot spots in the module.

[0043] The back-contact tandem photovoltaic module also includes a second interconnect grid line 900, with each of the multiple second fine grids 300 connected to the second interconnect grid line 900. By setting up the second interconnect grid line 900, the current on the multiple second fine grids 300 is combined, shortening the current transmission path. Furthermore, the second interconnect grid line 900 connects multiple second fine grids 300 in parallel, which can balance the current density of each second fine grid 300, avoiding local overheating. When a single second fine grid 300 fails, the second interconnect grid line 900 provides a bypass path, reducing the risk of hot spots in the module.

[0044] In some embodiments, the first interconnect gate line 800 and the second interconnect gate line 900 extend along a first direction, and are arranged opposite to each other in a second direction, with the first interconnect gate line 800 parallel to each other. This application achieves polarity isolation and current distribution of the fine gate lines through the separate arrangement of the first interconnect gate line 800 and the second interconnect gate line 900. For example, the first interconnect gate line 800 is used to collect the hole current of the positive electrode fine gate, and the second interconnect gate line 900 is used to collect the electron current of the negative electrode fine gate. The two interconnect gate lines achieve physical isolation, forming a dual-channel current distribution and reducing the risk of leakage current. Preferably, the first interconnect gate line 800 is parallel to each other. This creates a positive interconnection between the interconnect gate lines and the fine gate lines, forming a uniform support network that effectively distributes the load and reduces the risk of cell fragmentation. Especially in shingled modules, the interconnect grid lines are placed on the outer edge of the cell, which can be directly overlapped and welded with the interconnect grid lines of the adjacent cell 100 to form a connection between the cells 100, eliminating the need for bridging solder strips.

[0045] In this embodiment, a photovoltaic system includes the aforementioned back-contact stacked photovoltaic module. In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants, and can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system grid as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0046] In the description of this specification, the use of terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., refers to specific features, structures, materials, or characteristics described in connection with the embodiments or examples, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back-contact stacked-grid photovoltaic module, characterized in that, The device includes a battery cell and a plurality of first fine grids and a plurality of second fine grids alternately disposed on the battery cell along a first direction, wherein the polarities of the first fine grids and the second fine grids are opposite; a plurality of first solder strips are disposed on the plurality of first fine grids in a one-to-one correspondence, and a plurality of second solder strips are disposed on the plurality of second fine grids in a one-to-one correspondence, wherein the first solder strips, the second solder strips, the first fine grids and the second fine grids extend along a second direction; and a first busbar extends along the first direction, wherein the plurality of first solder strips are connected to the first busbar. A second busbar extends along the first direction, and a plurality of second solder strips are connected to the second busbar; wherein the plurality of first solder strips are respectively insulated from the second busbar, and the plurality of second solder strips are respectively insulated from the first busbar.

2. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, Multiple first solder strips are respectively spaced apart from the second busbar.

3. The back-contact stacked-grid photovoltaic module as described in claim 2, characterized in that, Multiple second welding strips are respectively spaced apart from the first busbar.

4. The back-contact stacked-grid photovoltaic module as described in claim 3, characterized in that, The distance between the first welding strip and the second busbar is 1 to 10 mm, and / or the distance between the second welding strip and the first busbar is 1 to 10 mm.

5. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The first welding strip is one of round welding strip, triangular welding strip or flat welding strip, and / or the second welding strip is one of round welding strip, triangular welding strip or flat welding strip.

6. The back-contact tandem photovoltaic module as described in claim 1, characterized in that, It also includes a fixing strap that extends along the first direction and is used to fix a plurality of first welding strips and a plurality of second welding strips.

7. The back-contact stacked-grid photovoltaic module as described in claim 6, characterized in that, There are multiple fixing straps, and the multiple fixing straps are distributed at intervals along the second direction.

8. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The diameter of the first welding strip is in the range of 0.05 to 0.2 mm, and the diameter of the first manifold is in the range of 0.05 to 5 mm.

9. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The diameter of the second welding strip is in the range of 0.05 to 0.2 mm, and the diameter of the second manifold is in the range of 0.05 to 5 mm.

10. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The cross-section of the first busbar is one of a circle, a triangle, or a rectangle, and / or the cross-section of the second busbar is one of a circle, a triangle, or a rectangle.

11. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The back-contact stacked-grid photovoltaic module further includes a first interconnect grid line, and each of the plurality of first fine grids is connected to the first interconnect grid line.

12. The back-contact stacked-grid photovoltaic module as described in claim 11, characterized in that, The back-contact stacked-grid photovoltaic module also includes a second interconnect grid line, and each of the plurality of second fine grids is connected to the second interconnect grid line.

13. The back-contact stacked-grid photovoltaic module as described in claim 12, characterized in that, The first interconnect gate line and the second interconnect gate line extend along the first direction, and the first interconnect gate line and the second interconnect gate line are arranged opposite to each other in the second direction, and the first interconnect gate line and the second interconnect gate line are parallel to each other.

14. A photovoltaic system, characterized in that, Includes the back-contact stacked-grid photovoltaic module as described in any one of claims 1-13.

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