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 solar cells and a plurality of fine grids spaced apart on the solar cells along a first direction; a plurality of electrical connection layers are correspondingly disposed on the plurality of fine grids, the extension direction of the electrical connection layers is in the same direction as the extension direction of the fine grids, and the width of the electrical connection layer in the first direction is less than or equal to the width of the fine grids in the first direction. By correspondingly disposing of the plurality of electrical connection layers on the plurality of fine grids, and arranging the extension direction of the electrical connection layers in the same direction as the extension direction of the fine grids, the electrical connection layers can be disposed along the entire fine grid line, thus expanding the disposal area of ​​the electrical connection layers. In this way, when solder ribbons are stacked on the fine grids, the electrical connection layers located between the solder ribbons and the fine grids can effectively fix the solder ribbons, resulting in high connection strength between the solder ribbons and the fine grids, improving welding tensile strength, and achieving good welding effect.

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] In back-contact solar cells, to reduce the use of solder paste, a gridless design is adopted, with solder ribbons directly soldered onto the fine grid. However, in this technical solution, because the solder ribbons and fine grids are interleaved, and the solder paste is applied at the junction of the solder ribbons and fine grids, the application area of ​​the solder paste is limited, resulting in lower connection strength between the solder ribbons and fine grids, and making them prone to cold solder joints. Utility Model Content

[0003] This application provides a back-contact stacked grid photovoltaic module, which aims to solve the problem that due to the cross arrangement between the solder strip and the fine grid, the solder paste is placed at the connection between the solder strip and the fine grid, the solder paste placement area is limited, the connection strength between the solder strip and the fine grid is low, and the problem of poor soldering is easy to occur.

[0004] This application provides a back-contact stacked-grid photovoltaic module, comprising solar cells and a plurality of fine grids spaced apart on the solar cells along a first direction; a plurality of electrical connection layers are disposed on the plurality of fine grids in a one-to-one correspondence, wherein the extension direction of the electrical connection layers is the same as the extension direction of the fine grids, and the width of the electrical connection layers in the first direction is less than or equal to the width of the fine grids in the first direction.

[0005] Optionally, the electrical connection layer has a linear structure, and multiple electrical connection layers and multiple fine gates are arranged in a one-to-one correspondence.

[0006] Optionally, the electrical connection layer has a dotted structure, and multiple electrical connection layers on each fine gate are spaced apart in the extension direction of the fine gate.

[0007] Optionally, the shape of the electrical connection layer includes at least one of spindle, rectangular, circular, and gourd-shaped.

[0008] Optionally, the plurality of electrical connection layers located on two adjacent fine gates are staggered one-to-one in the extension direction of the fine gates.

[0009] Optionally, the projection point of the electrical connection layer on the adjacent fine gate is located at the exact midpoint between two adjacent electrical connection layers on the fine gate.

[0010] Optionally, the electrical connection layer includes low-temperature solder paste or high-temperature solder paste.

[0011] Optionally, the back-contact stacked photovoltaic module further includes multiple solder strips, with the multiple solder strips and the multiple fine grids stacked in a one-to-one correspondence, and the electrical connection layer disposed between the solder strips and the fine grids.

[0012] Optionally, a portion of the plurality of fine gates is a first fine gate, and another portion of the plurality of fine gates is a second fine gate. The first fine gate and the second fine gate are opposite in nature, and the plurality of first fine gates and the plurality of second fine gates are alternately arranged on the solar cell.

[0013] 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.

[0014] 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.

[0015] Optionally, 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.

[0016] Optionally, the first interconnect gate line and the first interconnect gate line are parallel to each other.

[0017] This application expands the area where multiple electrical connection layers are disposed one-to-one on multiple fine grids, with the extension direction of the electrical connection layers being the same as the extension direction of the fine grids. This allows for the placement of electrical connection layers along the entire fine grid line. When solder ribbons are stacked on the fine grids, the electrical connection layers located between the solder ribbons and the fine grids can effectively fix the solder ribbons, resulting in high connection strength between the solder ribbons and the fine grids, improved welding tensile strength, and better welding performance. Furthermore, the width of the electrical connection layer in the first direction is less than or equal to the width of the fine grids in the first direction, preventing contact between electrical connection layers on adjacent fine grid lines, avoiding short circuits between dissimilar fine grid lines, and ensuring reliable operation of the photovoltaic module.

[0018] On the other hand, this application provides a photovoltaic system including the aforementioned back-contact stacked-grid photovoltaic module. The technical effects of this application are the same as those of the aforementioned back-contact stacked-grid photovoltaic module, and will not be repeated here. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the back-contact stacked-grid photovoltaic module provided in the current application. Figure 1 ;

[0020] Figure 2 This is a schematic diagram of the back-contact stacked-grid photovoltaic module provided in the current application. Figure 2 ;

[0021] Figure 3 This is a partial schematic diagram of the back-contact stacked-grid photovoltaic module provided in the current application. Figure 1 ;

[0022] Figure 4 This is a partial schematic diagram of the back-contact stacked-grid photovoltaic module provided in the current application. Figure 2 .

[0023] Explanation of reference numerals in the attached figures:

[0024] 100, Solar cell; 200, Grid; 201, First grid; 202, Second grid; 300, Electrical connection layer; 400, Solder ribbon; 500, First interconnect grid line; 600, Second interconnect grid line. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] like Figure 1As shown in the embodiments of this application, a back-contact stacked-grid photovoltaic module includes a solar cell 100 and a plurality of fine grids 200 spaced apart along a first direction on the solar cell 100. 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 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 grids 200 include positive 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.

[0032] 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.

[0033] 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.

[0034] In some embodiments, multiple electrical connection layers 300 are correspondingly disposed on multiple fine gates 200. The extension direction of the electrical connection layer 300 is the same as the extension direction of the fine gate 200, and the width of the electrical connection layer 300 in the first direction is less than or equal to the width of the fine gate 200 in the first direction. That is, one electrical connection layer 300 is disposed on each fine gate 200. In this embodiment, the fine gate 200 extends along the second direction, and the electrical connection layer 300 also extends along the second direction. The electrical connection layer 300 and the fine gate 200 are arranged in the same direction. For example, the entire fine gate 200 may be provided with an electrical connection layer 300, or the entire fine gate 200 may be provided with an electrical connection layer 300 intermittently, or the fine gate 200 may be provided with an electrical connection layer 300 partially. This application does not limit this. Further, the electrical connection layer 300 includes low-temperature solder paste or high-temperature solder paste. For example, the low-temperature solder paste can be Sn-Bi, and its operating temperature range is 150-190°C. Applying the low-temperature solder paste can reduce damage to the solar cell 100. The high-temperature solder paste can be Sn-Ag-Cu, and its operating temperature range is 230-250°C. Applying the high-temperature solder paste provides higher soldering strength.

[0035] Compared to traditional solder paste that is only applied at the intersection of the solder ribbon 400 and the fine grid 200, the arrangement in this embodiment greatly expands the area of ​​the electrical connection layer 300. Thus, when the solder ribbon 400 is stacked on top of the fine grid 200, the electrical connection layer 300 located between the solder ribbon 400 and the fine grid 200 can effectively fix the solder ribbon 400. The solder ribbon 400 and the fine grid 200 have high connection strength, improving welding pull force and resulting in good welding effect. Furthermore, the width of the electrical connection layer 300 in the first direction is less than or equal to the width of the fine grid 200 in the first direction, preventing short circuits caused by lateral overflow of molten solder paste bridging adjacent opposite-polarity fine grids 200 during reflow soldering, ensuring reliable operation of the photovoltaic module.

[0036] 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.

[0037] like Figure 4 As shown, in some embodiments, the electrical connection layer 300 has a linear structure, and multiple electrical connection layers 300 and multiple fine gates 200 are arranged in a one-to-one correspondence. That is, each fine gate 200 is provided with an electrical connection layer 300, and the electrical connection layer 300 extends in the second direction to form a continuous and uninterrupted linear structure. The shape of the electrical connection layer 300 is adapted to the shape of the fine gate 200, which can ensure that the electrical connection layer 300 and the fine gate 200 form a full contact surface, thereby minimizing the contact resistance.

[0038] like Figure 3 As shown, in some embodiments, the electrical connection layer 300 has a dotted structure, with the electrical connection layers 300 on each fine grid 200 spaced apart along the extension direction of the fine grid 200. That is, the electrical connection layers 300 are discretely distributed on each fine grid 200, and the discrete distribution trend of the electrical connection layers 300 is consistent with the extension direction of the fine grid 200. This provides a safety buffer even if some electrical connection layers 300 are misaligned, reducing alignment accuracy and improving yield. Furthermore, the dot density of the discrete distribution of the electrical connection layers 300 is adjustable, allowing for more flexible arrangement of the electrical connection layers 300. For example, the dot density can be increased in high-current regions (battery edges) to reduce lateral resistance. In addition, the spaced electrical connection layers 300 effectively reduce material damage and lower component production costs while ensuring the connection strength between the solder ribbon 400 and the fine grid 200. Furthermore, the shape of the discretely distributed point-like electrical connection layer 300 includes at least one of spindle, rectangular, circular, and gourd-shaped forms, which is not limited in this application. Based on the characteristics of different shapes of the electrical connection layer 300, the actual selection of the shape of the electrical connection layer 300 also needs to consider system design factors such as the width of the fine gate 200 and soldering parameters. For example, a rectangular electrical connection layer 300 with sharp boundary angles helps suppress diffusion, while a circular electrical connection layer 300 has good isotropic properties and uniform stress distribution. It should be noted that, due to the fluidity of solder paste, the above description of the shape of the electrical connection layer 300 is not a strict geometric limitation; a general similarity in outline is sufficient, and even local deformation is permissible.

[0039] In some embodiments, multiple electrical connection layers 300 located on two adjacent fine grids 200 are staggered one-to-one in the extending direction of the fine grids 200. Since the polarities of adjacent fine grids 200 are opposite, a short circuit could easily occur if the electrical connection layers 300 are perfectly aligned. However, with the staggered arrangement, even if there is lateral offset, there is sufficient buffer distance. Furthermore, because the spacing between the fine grids 200 is extremely small, the staggered design of the electrical connection layers 300 greatly improves the yield of shingled modules. Specifically, the multiple electrical connection layers 300 on two adjacent fine grids 200 can be staggered at equal intervals in a stepped manner or staggered at unequal intervals in a random lattice manner. The specific arrangement can be set according to the shape of the electrical connection layers 300 and the soldering temperature. Preferably, the projection point of the electrical connection layer 300 on the adjacent fine grids 200 is located at the exact midpoint between two adjacent electrical connection layers 300 on the fine grid 200. In other words, based on the mutual misalignment of the electrical connection layers 300 on two adjacent fine gates 200, the electrical connection layers 300 on two adjacent fine gates 200 are also equally spaced and misaligned in the second direction. On the one hand, this can avoid short circuits caused by contact between the electrical connection layers 300 on adjacent fine gates 200, and on the other hand, it facilitates the implementation of the printing process for the electrical connection layers 300 and reduces the requirements for the production process.

[0040] like Figure 2 As shown, in some embodiments, the back-contact stacked photovoltaic module further includes multiple solder ribbons 400, which are stacked one-to-one with multiple fine grids 200, and an electrical connection layer 300 is disposed between the solder ribbons 400 and the fine grids 200. In this embodiment, each fine grid 200 is provided with a solder ribbon 400. Specifically, the solder ribbon 400 and the fine grid 200 extend in the same direction, that is, the solder ribbon 400 also extends along the second direction. Combined with the electrical connection layer 300 extending between the solder ribbon 400 and the fine grid 200, the electrical connection layer 300, the solder ribbon 400, and the fine grid 200 extend in the same direction, which can achieve a high-strength connection between the solder ribbon 400 and the fine grid 200 and avoid the phenomenon of poor soldering of the solder ribbon 400.

[0041] In some embodiments, a portion of the plurality of fine grids 200 is a first fine grid 201, and another portion is a second fine grid 202. The first fine grids 201 and the second fine grids 202 have opposite polarities, and the plurality of first fine grids 201 and the plurality of second fine grids 202 are alternately arranged on the solar cell 100. Specifically, the first fine grid 201 can be a positive electrode fine grid, and the second fine grid 202 can be a negative electrode fine grid. Of course, in other embodiments, the first fine grid 201 can also be a negative electrode fine grid, and the second fine grid 202 can be a positive electrode fine grid. The polarity of the fine grids 200 is determined according to the type of doped region they are configured with. The plurality of first fine grids 201 and the plurality of second fine grids 202 are alternately arranged on the solar cell 100, that is, the polarities of each adjacent pair of fine grids 200 are opposite. Such an electrode pattern arrangement is beneficial to the uniform distribution of current on the solar cell 100.

[0042] In some embodiments, the back-contact stacked-grid photovoltaic module further includes a first interconnect grid line 500, with each of the plurality of first fine grids 201 connected to the first interconnect grid line 500. By setting the first interconnect grid line 500, the current on the plurality of first fine grids 201 is combined, shortening the current transmission path. Furthermore, the first interconnect grid line 500 connects multiple first fine grids 201 in parallel, which can balance the current density of each first fine grid 201 and avoid local overheating. When a single first fine grid 201 fails, the first interconnect grid line 500 provides a bypass channel, reducing the risk of hot spots in the module.

[0043] In some embodiments, the back-contact tandem photovoltaic module further includes a second interconnect grid line 600, with each of the plurality of second fine grids 202 connected to the second interconnect grid line 600. By setting the second interconnect grid line 600, the current on the plurality of second fine grids 202 is combined, shortening the current transmission path. Furthermore, the second interconnect grid line 600 connects multiple second fine grids 202 in parallel, which can balance the current density of each second fine grid 202 and avoid local overheating. When a single second fine grid 202 fails, the second interconnect grid line 600 provides a bypass channel, reducing the risk of hot spots in the module.

[0044] Furthermore, the first interconnect grid line 500 and the second interconnect grid line 600 extend along a first direction, and are arranged opposite to each other in a second direction. This application achieves polarity isolation and current distribution of the fine grid 200 through the separate arrangement of the first interconnect grid line 500 and the second interconnect grid line 600. For example, the first interconnect grid line 500 is used to collect the hole current of the positive fine grid, and the second interconnect grid line 600 is used to collect the electron current of the negative fine grid. The two interconnect grid lines achieve physical isolation, forming a dual-channel current distribution and reducing the risk of leakage current. Preferably, the first interconnect grid line 500 is parallel to each other. This allows the interconnect grid lines and the fine grid 200 to be positively interconnected, forming a uniform support network, effectively distributing the load and reducing the risk of cell fragmentation. Especially in shingled modules, placing the interconnect grid lines on the outer edge of the cell allows for direct overlapping welding with the interconnect grid lines of adjacent cells 100, forming a connection between cells 100, eliminating the need for the bridging solder strip 400.

[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 gate photovoltaic module, characterized by, It includes a battery cell and a plurality of fine grids spaced apart on the battery cell along a first direction; a plurality of electrical connection layers are disposed on the plurality of fine grids in a one-to-one correspondence, the extension direction of the electrical connection layers is in the same direction as the extension direction of the fine grids, and the width of the electrical connection layers in the first direction is less than or equal to the width of the fine grids in the first direction.

2. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The electrical connection layer has a linear structure, and multiple electrical connection layers and multiple fine gates are arranged in a one-to-one correspondence.

3. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The electrical connection layer has a dotted structure, and multiple electrical connection layers on each fine gate are spaced apart in the extension direction of the fine gate.

4. The back-contact stacked-grid photovoltaic module as described in claim 3, characterized in that, The shape of the electrical connection layer includes at least one of spindle, rectangular, circular, and gourd shapes.

5. The back-contact stacked-grid photovoltaic module as described in claim 3, characterized in that, The multiple electrical connection layers located on two adjacent fine gates are staggered one-to-one in the extension direction of the fine gates.

6. The back-contact stacked-grid photovoltaic module as described in claim 5, characterized in that, The projection point of the electrical connection layer on the adjacent fine gate is located at the exact midpoint between two adjacent electrical connection layers on the fine gate.

7. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The electrical connection layer includes low-temperature solder paste or high-temperature solder paste.

8. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, The back-contact stacked photovoltaic module also includes multiple solder strips, which are stacked one-to-one with the multiple fine grids, and the electrical connection layer is disposed between the solder strips and the fine grids.

9. The back-contact stacked-grid photovoltaic module as described in claim 1, characterized in that, A portion of the plurality of fine gates is a first fine gate, and another portion of the plurality of fine gates is a second fine gate. The first fine gate and the second fine gate are opposite in nature, and the plurality of first fine gates and the plurality of second fine gates are alternately arranged on the solar cell.

10. The back-contact stacked-grid photovoltaic module as described in claim 9, 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.

11. The back-contact stacked-grid photovoltaic module as described in claim 10, 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.

12. The back-contact stacked-grid photovoltaic module as described in claim 11, 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.

13. The back-contact stacked-grid photovoltaic module as described in claim 12, characterized in that, The first interconnect gate line and the first 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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