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 multiple solar cells, which are partially overlapped along a second direction; and multiple fine grids spaced apart on each solar cell along a first direction; and a solder ribbon mesh stacked on the solar cells, the solder ribbon mesh including a first solder ribbon sub-mesh and a second solder ribbon sub-mesh. This application facilitates the series welding of multiple solar cells by setting a solder ribbon mesh on the solar cells. The solder ribbon mesh can be connected to multiple fine grids simultaneously. The first solder ribbon mesh and the second solder ribbon mesh can be connected to fine grids of different polarities respectively, realizing independent current collection of positive and negative fine grids. The solder ribbon mesh structure can align and fix multiple solder ribbons to multiple fine grids at one time, reducing the difficulty of solder ribbon positioning.

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 photovoltaic module includes multiple solar cells, which are partially overlapped along a second direction; and multiple fine grids spaced apart on each solar cell along a first direction; and a solder strip mesh stacked on the solar cells, the solder strip mesh including a first solder strip sub-mesh and a second solder strip sub-mesh, the first solder strip sub-mesh and the second solder strip sub-mesh being insulated from each other, a portion of the fine grids being connected to the first solder strip mesh, another portion of the fine grids being connected to the second solder strip mesh, and the first solder strip sub-mesh of one of two adjacent solar cells being connected to the second solder strip mesh of the other of the two adjacent solar cells.

[0005] Optionally, the first welding strip has a first busbar extending out of the battery cell, the first busbar being bent in a direction away from the battery cell to form a first rolled edge, the projection of the first rolled edge onto the battery cell being located on the battery cell.

[0006] Optionally, the minimum distance between the first rolled edge and the edge of the battery cell ranges from 1 to 3 mm.

[0007] Optionally, the second ribbon mesh has a second busbar extending out of the solar cell, and the first rolled edge of the first ribbon mesh of one of the two adjacent solar cells is connected to the second busbar of the second ribbon mesh of the other of the two adjacent solar cells.

[0008] Optionally, the second busbar is bent in a direction away from the battery cell to form a second rolled edge portion, the projection of the second rolled edge portion onto the battery cell is located on the battery cell, and the first rolled edge portion of the first solder strip mesh of one of the two adjacent battery cells and the second rolled edge portion of the second solder strip mesh of the other of the two adjacent battery cells are connected by a conductive connector.

[0009] Optionally, the minimum distance between the second rolled edge and the edge of the battery cell ranges from 1 to 3 mm.

[0010] Optionally, the first solder strip subnet includes a first busbar and a plurality of first solder strips respectively connected to the first busbar. The plurality of first solder strips and the portion of the fine grid are arranged in a one-to-one correspondence. The first solder strips and the fine grid are respectively arranged to extend along the second direction, and the first busbar is arranged to extend along the first direction.

[0011] Optionally, the second welding strip subnet includes a second busbar and a plurality of second welding strips respectively connected to the second busbar. The plurality of second welding strips and the fine grid of the other part are arranged in a one-to-one correspondence. The second welding strips and the fine grid are respectively arranged to extend along the second direction, and the second busbar is arranged to extend along the first direction.

[0012] Optionally, the conductive connector includes a plurality of connecting strips, which are connected one-to-one between a plurality of first strips of one adjacent cell and a plurality of second strips of the other adjacent cell.

[0013] Optionally, it also includes a fixing strip disposed on each of the battery cells, the fixing strip extending along the first direction, the fixing strip being used to fix the welding wire mesh.

[0014] Optionally, there are multiple fixing strips, which are spaced apart on the battery cell along the second direction, wherein the width of the fixing strip located in the edge region of the battery cell is greater than the width of the fixing strip located in the middle region of the battery cell.

[0015] Optionally, the width of the fixing strip located in the edge region of the battery cell ranges from 3 to 7 mm.

[0016] Optionally, in the second direction, the difference between the length of the welding strip and the length of the battery cell ranges from 6 to 10 mm.

[0017] Optionally, one portion of the fine grid is a first fine grid, and the other portion of the fine grid is a second fine grid. The first fine grid and the second fine grid are opposite in nature, and a plurality of first fine grids and a plurality of second fine grids are alternately arranged on the solar cell.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] This application facilitates the series welding of multiple solar cells by setting a welding ribbon mesh on the solar cell. The welding ribbon mesh can be connected to multiple grids at the same time. The welding ribbon mesh includes a first welding ribbon sub-mesh and a second welding ribbon sub-mesh. The first welding ribbon sub-mesh and the second welding ribbon sub-mesh can be connected to grids of different polarities respectively, so as to realize independent current collection of positive and negative grids. The welding ribbon mesh structure can align and fix multiple welding ribbons to multiple grids at one time, reducing the difficulty of positioning the welding ribbons. Attached Figure Description

[0022] Figure 1 This is a structural schematic diagram of the first type of back-contact stacked-grid photovoltaic module provided in the current application;

[0023] Figure 2 This is a structural schematic diagram of the second type of back-contact stacked-grid photovoltaic module provided in the current application;

[0024] Figure 3 This is a structural schematic diagram of the third type of back-contact stacked-grid photovoltaic module provided in the current application;

[0025] Figure 4 This is a structural schematic diagram of the fourth type of back-contact stacked-grid photovoltaic module provided in the current application;

[0026] Figure 5 This is a structural schematic diagram of the fifth type of back-contact stacked-grid photovoltaic module provided in the current application;

[0027] Figure 6 This is a structural schematic diagram of the conductive connector for the fifth type of back-contact stacked-grid photovoltaic module provided in the current application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 100. Battery cell; 200. Welding strip mesh; 201. First welding strip sub-mesh; 2011. First busbar; 2012. First welding strip; 202. Second welding strip sub-mesh; 2021. Second busbar; 2022. Second welding strip; 203. First rolled edge portion; 204. Second busbar section; 205. Second rolled edge portion; 206. First busbar section; 300. Fine grid; 301. First fine grid; 302. Second fine grid; 400. Conductive connector; 401. Connecting welding strip; 402. First busbar welding strip; 403. Second busbar welding strip; 500. Fixing strip; 600. First interconnecting grid line; 700. Second interconnecting grid line. Detailed Implementation

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] like Figure 1 As shown in the embodiments of this application, a back-contact stacked-grid photovoltaic module includes multiple solar cells 100, which are partially overlapped along a second direction to form a shingled solar cell module. Multiple fine grids 300 are spaced apart on each solar cell 100 along a first direction. Specifically, the solar cells 100 can be made of semiconductor materials. The back side of the solar cells 100 is precisely patterned to form alternating P-type and N-type doped regions through a doping process, such as laser doping, photolithography, or ion implantation. The positions of the doped regions correspond to the printed / electroplated fine grids. The fine grids 300 include positive and negative grids. The positive grids contact the P-type doped regions, and the negative grids contact the N-type doped regions. The positive and negative grids are spaced apart to insulate the dissimilar grids. It is understood that in other embodiments of this application, the structure of the solar cells 100 can be configured differently, which is not limited here. However, it should be noted that in any type of battery cell 100, it is configured to have a positive electrode grid in the P-type doped region and a negative electrode grid in the N-type doped region.

[0037] 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 its positive and negative grids is determined based on the actual size of the solar cell 100, and the width and distance between the positive and negative grids, and is not specifically limited here.

[0038] 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.

[0039] like Figure 2 As shown, in some embodiments, the welding ribbon mesh 200 can be prefabricated. The welding ribbon mesh 200 has a mesh structure and contains multiple welding ribbons. The welding ribbons in the welding ribbon mesh 200 are interconnected to form a whole. The spacing and number of welding ribbons in the welding ribbon mesh 200 need to be adapted to the spacing and number of fine grids 300 on the solar cell 100. In this way, the welding ribbon mesh 200 is stacked on the solar cell 100, and the welding ribbons in the welding ribbon mesh 200 are simultaneously aligned and fixed with all the fine grids 300 on the solar cell 100. Compared with the traditional method of welding a single welding ribbon to the solar cell 100 separately, using a prefabricated welding ribbon mesh 200 for welding ribbon installation is convenient and efficient. Furthermore, since the welding ribbon mesh 200 is a complete coverage, even if some individual welding ribbons in the welding ribbon mesh 200 have poor welding, it will not affect the overall connection strength between the welding ribbon mesh 200 and the solar cell 100.

[0040] Furthermore, the welding strip mesh 200 includes a first welding strip sub-mesh 201 and a second welding strip sub-mesh 202. The first welding strip sub-mesh 201 and the second welding strip sub-mesh 202 are insulated from each other. A portion of the fine grid 300 is connected to the first welding strip sub-mesh 201, and another portion of the fine grid 300 is connected to the second welding strip mesh 202. The first welding strip sub-mesh 201 of one of two adjacent battery cells 100 is connected to the second welding strip mesh 202 of the other of the two adjacent battery cells 100. Understandably, the polarities of one portion of the fine grid 300 and the other portion of the fine grid 300 are opposite. For example, one portion of the fine grid 300 is a positive fine grid, and the other portion is a negative fine grid. The solder strip mesh 200 is correspondingly divided into a first solder strip sub-mesh 201 and a second solder strip sub-mesh 202 to distinguish the positive and negative poles of the solder strip mesh. The first solder strip sub-mesh 201 is connected to all the positive fine grids, and the second solder strip sub-mesh 202 is connected to all the negative fine grids, realizing independent current collection for the positive and negative fine grids 300. Adjacent cells 100 are connected in series through solder strip sub-meshes of opposite polarities, omitting the need for series solder strips, simplifying the series connection process, and improving production efficiency.

[0041] In some embodiments, the first welding ribbon mesh 201 has a first busbar section 206 extending out of the solar cell 100. The first busbar section 206 is bent in a direction away from the solar cell 100 to form a first rolled edge portion 203. The projection of the first rolled edge portion 203 onto the solar cell 100 is located on the solar cell 100. Specifically, a portion of the first busbar 2011 and the first welding ribbon 2012 constitutes the first busbar section 206. The portion of the first welding ribbon 2012 is bent away from the solar cell 100, so that the first busbar section 206 forms the first rolled edge portion 203. The first rolled edge portion 203 is located within the solar cell 100 to avoid stacking adjacent solar cells 100. In this embodiment, the connection of the welding ribbon meshes 200 on adjacent solar cells 100 in the shingled solar cell assembly is achieved by bending the first busbar section 206.

[0042] like Figure 3 , Figure 4 and Figure 5 As shown, the connection methods of the welding strip mesh 200 on adjacent solar cells 100 further include at least the following two:

[0043] In some embodiments, the second ribbon mesh 202 has a second busbar section 204 extending out of the battery cell 100. The first rolled edge 203 of the first ribbon mesh 201 of one of the adjacent battery cells 100 is connected to the second busbar section 204 of the second ribbon mesh 202 of the other adjacent battery cell 100. That is, the second busbar section 204 extending out of the second ribbon mesh 202 is not bent, and the second busbar section 204 extends straight out of the outer side of the battery cell 100. The ribbon mesh 200 on each battery cell 100 forms a single-sided inward roll, so that the first rolled edge 203 of one of the adjacent battery cells 100 and the second busbar section 204 of the other overlap and connect, realizing the series connection of adjacent battery cells 100.

[0044] In other embodiments, the second busbar 204 is bent away from the battery cell 100 to form a second rolled edge 205. The projection of the second rolled edge 205 onto the battery cell 100 is located on the battery cell 100. The first rolled edge 203 of the first solder strip mesh 201 of one of the two adjacent battery cells 100 and the second rolled edge 205 of the second solder strip mesh 202 of the other two adjacent battery cells 100 are connected by a conductive connector 400. That is, the second busbar 204 extending from the second solder strip mesh 202 is also bent to form a second rolled edge 205. The first rolled edge 203 and the second rolled edge 205 are both located inside the battery cell 100. The solder strip mesh 200 on each battery cell 100 forms a double-sided inward roll. A conductive connector 400 is provided between the first rolled edge 203 of one of the two adjacent battery cells 100 and the second rolled edge 205 of the other to conduct electricity, thereby realizing the series connection of adjacent battery cells 100.

[0045] like Figure 6 As shown, the conductive connector 400 includes multiple connecting ribbons 401, which are connected one-to-one between multiple first ribbons 2012 of one of the adjacent battery cells 100 and multiple second ribbons 2022 of the other of the two adjacent battery cells 100. The conductive connector 400 also includes a first bus ribbon 402 and a second bus ribbon 403, with the multiple connecting ribbons 401 connected between the first bus ribbon 402 and the second bus ribbon 403. Thus, the conductive connector 400 can be configured as a mesh structure adapted to the ribbon mesh 200. The conductive connector 400 can form a prefabricated connector, so that the conductive connector 400 can simultaneously connect multiple ribbons between two adjacent battery cells 100, simplifying the serial welding process.

[0046] Furthermore, the minimum distance between the first roll edge 203 and the edge of the battery cell 100 ranges from 1 to 3 mm. This minimum distance, which is also the width of the clearance area formed by the first busbar 206 bending onto the battery cell 100, is used for stacking adjacent battery cells 100. For example, the minimum distance between the first roll edge 203 and the edge of the battery cell 100 can be any value between 1 mm, 2 mm, 3 mm, or 1 mm to 3 mm; this application does not impose any limitation on this. This ensures that the edges of the battery cell 100 have sufficient space for stacking, avoiding interference from the welding wire mesh 200 on the stacking of the battery cell 100.

[0047] Similarly, the minimum distance between the second roll edge 205 and the edge of the battery cell 100 ranges from 1 to 3 mm. This minimum distance, which is also the width of the clearance area formed by the second busbar 204 bending onto the battery cell 100, is used for stacking adjacent battery cells 100. For example, the minimum distance between the second roll edge 205 and the edge of the battery cell 100 can be any value between 1 mm, 2 mm, 3 mm, or 1 mm to 3 mm; this application does not impose any limitation on this. This ensures that the edges of the battery cell 100 have sufficient space for stacking, avoiding interference from the welding wire mesh 200 on the stacking of the battery cell 100.

[0048] In some embodiments, the first solder strip subnet 201 includes a first busbar 2011 and a plurality of first solder strips 2012 respectively connected to the first busbar 2011. The plurality of first solder strips 2012 and a portion of fine grids 300 are arranged in a one-to-one correspondence. The first solder strips 2012 and fine grids 300 are respectively extended along a second direction, and the first busbar 2011 is extended along a first direction. In this embodiment, the first solder strip 2012 and the fine grid 300 are arranged in the same direction, and the first busbar 2011 and the first solder strip 2012 are arranged crosswise. The first busbar 2011 is used to interconnect all the first solder strips 2012 to realize the current of all the first solder strips 2012. The first solder strip 2012 and the fine grid 300 extend in the same direction and form a full contact surface, which can efficiently collect the current on the fine grid 300. Moreover, each first solder strip 2012 collects the current on each fine grid 300, forming a uniform electric field distribution. Compared with the traditional electrode connection structure, the electric field concentration at the edge of the battery cell 100 is caused by all the fine grids 300 being connected to the same polarity solder strip. The one-to-one correspondence between the solder strip and the fine grid 300 can eliminate the concentration of reverse bias at the edge of the battery.

[0049] In some embodiments, the second solder strip subnet 202 includes a second busbar 2021 and a plurality of second solder strips 2022 respectively connected to the second busbar 2021. The plurality of second solder strips 2022 and another portion of fine grids 300 are arranged in a one-to-one correspondence. The second solder strips 2022 and fine grids 300 are respectively arranged to extend along a second direction, and the second busbar 2021 is arranged to extend along a first direction. In this embodiment, the second solder strip 2022 and the fine grid 300 are arranged in the same direction, and the second busbar 2021 and the second solder strip 2022 are arranged crosswise. The second busbar 2021 is used to interconnect all the second solder strips 2022 to realize the current of all the second solder strips 2022. The extension direction of the second solder strip 2022 and the fine grid 300 is consistent, and the second solder strip 2022 and the fine grid 300 form a full contact surface, which can efficiently collect the current on the fine grid 300. Moreover, each second solder strip 2022 collects the current on each fine grid 300, forming a uniform electric field distribution. Compared with the traditional electrode connection structure, the electric field concentration at the edge of the battery cell 100 is caused by all the fine grids 300 being connected to the same polarity solder strip. In this application, the solder strips and fine grids 300 are arranged in a one-to-one correspondence to eliminate the concentration of reverse bias voltage at the edge of the battery.

[0050] 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.

[0051] In this embodiment, the battery assembly further includes a fixing strip 500 disposed on each battery cell 100. The fixing strip 500 extends along a first direction and is used to fix the welding strip mesh 200. Specifically, the fixing strip 500 can be a fixing tape, such as UV adhesive, UV thermosetting adhesive, pressure-sensitive adhesive, etc. The fixing strip 500 covers the welding strip mesh 200 and bonds it to the battery cell 100, achieving pre-fixation of the welding strip mesh 200. Subsequently, lamination welding is performed on the welding strip mesh 200 to further weld and fix it to the battery cell 100. It can be understood that there can be multiple fixing strips 500, which are spaced apart along a second direction. The number of fixing strips 500 can be determined according to the size of the battery cell 100 and the production process requirements. For example, four fixing strips 500 can be disposed spaced apart on the battery cell 100 in the second direction to fix the welding strip mesh 200. Preferably, the width of the fixing band 500 located at the edge region of the solar cell 100 is greater than the width of the fixing band 500 located in the middle region of the solar cell 100. Generally, the edge region of the module typically bears greater mechanical stress, such as from frame fixing, installation stress, wind pressure, snow load, or transportation vibration. Providing a wider fixing band 500 at the edge region of the solar cell 100 physically provides better support and connection strength, ensuring a tighter connection between the welding wire mesh 200 and the solar cell 100. This helps resist external stress, reduces the risk of solder joint breakage or incomplete soldering, and thus improves the mechanical stability of the entire battery string at the edge region. Further, the width of the fixing band 500 located at the edge region of the solar cell 100 ranges from 3 to 7 mm. Exemplarily, the width of the fixing band 500 located at the edge region of the solar cell 100 can be any value between 3 mm, 5 mm, 7 mm, or 3 mm to 7 mm; this application does not impose any limitation on this. Within the above range, the fixing band 500 can stably fix the welding wire mesh 200 to the solar cell 100.

[0052] In some embodiments, in the second direction, the difference between the length of the welding strip 200 and the length of the solar cell 100 ranges from 6 to 10 mm. The length of the welding strip 200 is greater than the length of the solar cell 100, and within the above-mentioned difference range, the welding strip 200 has sufficient redundant length for bending to form a rolled edge.

[0053] In some embodiments, a portion of the fine grid 300 is a first fine grid 301, and another portion is a second fine grid 302. The first fine grid 301 and the second fine grid 302 have opposite polarities, and multiple first fine grids 301 and multiple second fine grids 302 are alternately arranged on the solar cell 100. Specifically, the first fine grid 301 can be a positive electrode fine grid, and the second fine grid 302 can be a negative electrode fine grid. Of course, in other embodiments, the first fine grid 301 can be a negative electrode fine grid, and the second fine grid 302 can be a positive electrode fine grid. The polarity of the fine grid 300 is determined according to the type of doped region it is provided with. The multiple first fine grids 301 and multiple second fine grids 302 are alternately arranged on the solar cell 100, that is, the polarities of each adjacent pair of fine grids 300 are opposite. Such an electrode pattern arrangement is beneficial to the uniform distribution of current on the solar cell 100.

[0054] The back-contact tandem photovoltaic module also includes a first interconnect grid line 600, with each of the plurality of first fine grids 301 connected to the first interconnect grid line 600. By setting the first interconnect grid line 600, the current on the plurality of first fine grids 301 is combined, shortening the current transmission path. Furthermore, the first interconnect grid line 600 connects multiple first fine grids 301 in parallel, which can balance the current density of each first fine grid 301 and avoid local overheating. When a single first fine grid 301 fails, the first interconnect grid line 600 provides a bypass channel, reducing the risk of hot spots in the module.

[0055] The back-contact tandem photovoltaic module also includes a second interconnect grid line 700, with each of the multiple second fine grids 302 connected to the second interconnect grid line 700. By setting the second interconnect grid line 700, the current on the multiple second fine grids 302 is combined, shortening the current transmission path. Furthermore, the second interconnect grid line 700 connects multiple second fine grids 302 in parallel, which can balance the current density of each second fine grid 302 and avoid local overheating. When a single second fine grid 302 fails, the second interconnect grid line 700 provides a bypass channel, reducing the risk of hot spots in the module.

[0056] In some embodiments, the first interconnect gate line 600 and the second interconnect gate line 700 extend along a first direction, and are arranged opposite to each other in a second direction, with the first interconnect gate line 600 and the second interconnect gate line 700 being parallel to each other. This application achieves polarity isolation and current distribution of the fine gate 300 through the separate arrangement of the first interconnect gate line 600 and the second interconnect gate line 700. For example, the first interconnect gate line 600 is used to collect the hole current of the positive electrode fine gate, and the second interconnect gate line 700 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 600 and the second interconnect gate line 700 are parallel to each other. In this way, the interconnect gate lines and the fine gate 300 are positively interconnected, forming a uniform support network, effectively distributing the load and reducing 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.

[0057] 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.

[0058] 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.

[0059] 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 gate photovoltaic module, characterized by, The device includes multiple solar cells, which are partially overlapped along a second direction; and multiple fine grids spaced apart on each solar cell along a first direction; and a bonding wire mesh stacked on the solar cells, the bonding wire mesh including a first bonding wire mesh and a second bonding wire mesh, the first bonding wire mesh and the second bonding wire mesh being insulated from each other, a portion of the fine grids being connected to the first bonding wire mesh, another portion of the fine grids being connected to the second bonding wire mesh, and the first bonding wire mesh of one of two adjacent solar cells being connected to the second bonding wire mesh of the other of the two adjacent solar cells.

2. The back contact crossbar photovoltaic assembly of claim 1, wherein, The first welding strip has a first busbar extending out of the battery cell, the first busbar being bent in a direction away from the battery cell to form a first rolled edge, the projection of the first rolled edge onto the battery cell being located on the battery cell.

3. The back contact crossbar photovoltaic assembly of claim 2, wherein, The minimum distance between the first rolled edge and the edge of the battery cell ranges from 1 to 3 mm.

4. The back contact crossbar photovoltaic assembly of claim 2, wherein, The second welding strip mesh has a second busbar extending out of the solar cell, and the first rolled edge of the first welding strip mesh of one of the two adjacent solar cells is connected to the second busbar of the second welding strip mesh of the other of the two adjacent solar cells.

5. The back contact crossbar photovoltaic assembly of claim 4, wherein, The second busbar bends in a direction away from the battery cell to form a second rolled edge. The projection of the second rolled edge onto the battery cell is located on the battery cell. The first rolled edge of the first weld strip mesh of one of the two adjacent battery cells and the second rolled edge of the second weld strip mesh of the other of the two adjacent battery cells are connected by a conductive connector.

6. The back contact crossbar photovoltaic assembly of claim 5, wherein, The minimum distance between the second rolled edge and the edge of the battery cell ranges from 1 to 3 mm.

7. The back contact stacked grid photovoltaic assembly of claim 5, wherein, The first solder strip subnet includes a first busbar and a plurality of first solder strips respectively connected to the first busbar. The plurality of first solder strips and the fine grid of the portion are arranged in a one-to-one correspondence. The first solder strips and the fine grid are respectively arranged to extend along the second direction. The first busbar is arranged to extend along the first direction.

8. The back-contact stacked-grid photovoltaic module as described in claim 7, characterized in that, The second welding strip subnet includes a second busbar and a plurality of second welding strips respectively connected to the second busbar. The plurality of second welding strips and the fine grid of the other part are arranged in a one-to-one correspondence. The second welding strips and the fine grid are respectively arranged to extend along the second direction, and the second busbar is arranged to extend along the first direction.

9. The back-contact stacked-grid photovoltaic module as described in claim 8, characterized in that, The conductive connector includes multiple connecting strips, which are connected one-to-one between multiple first strips of one adjacent cell and multiple second strips of the other adjacent cell.

10. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, It also includes a fixing strip disposed on each of the battery cells, the fixing strip extending along the first direction, the fixing strip being used to fix the welding strip mesh.

11. The back-contact stacked-grid photovoltaic module as described in claim 10, characterized in that, There are multiple fixing strips, which are distributed at intervals along the second direction on the battery cell. The width of the fixing strip located at the edge region of the battery cell is greater than the width of the fixing strip located in the middle region of the battery cell.

12. The back-contact stacked-grid photovoltaic module as described in claim 11, characterized in that, The width of the fixing strip located at the edge region of the battery cell ranges from 3 to 7 mm.

13. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, In the second direction, the difference between the length of the welding strip and the length of the battery cell ranges from 6 to 10 mm.

14. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, One portion of the fine grid is a first fine grid, and the other portion of the fine grid is a second fine grid. The first fine grid and the second fine grid are opposite in nature, and a plurality of first fine grids and a plurality of second fine grids are alternately arranged on the solar cell.

15. The back-contact stacked-grid photovoltaic module as described in claim 14, 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.

16. The back-contact stacked-grid photovoltaic module as described in claim 15, 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.

17. The back-contact stacked-grid photovoltaic module as described in claim 16, 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.

18. A photovoltaic system, characterized in that, Includes the back-contact stacked-grid photovoltaic module as described in any one of claims 1-17.

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