Photovoltaic cell interconnection method and photovoltaic cell assembly

Abstract

The invention discloses a photovoltaic cell interconnection method and a photovoltaic cell assembly, and relates to the technical field of photovoltaic cells, and the method comprises the steps: arranging a positive electrode bus bar at the edge of a first side edge of a plane where a positive electrode of a photovoltaic cell is located, and arranging a negative electrode bus bar at the edge of a second side edge of a plane where a negative electrode of the photovoltaic cell is located, respectively connecting the anode bus bar and the cathode bus bar with an anode welding strip and a cathode welding strip on the photovoltaic cell; the method comprises the following steps of: connecting positive and negative electrode welding strips of a plurality of adjacent photovoltaic cells to form a photovoltaic cell string A, rotating by 180 degrees to obtain a photovoltaic cell string A ', and connecting in series to form a cell string interconnection unit B; mirroring by taking a straight line where the positive and negative output ports of the battery string interconnection unit B are located as an axis to obtain a battery string interconnection unit B ', and connecting in parallel to form a parallel structure; and carrying out transverse expansion on the parallel structure, carrying out series connection to form a series-parallel structure, and packaging each structure to obtain the photovoltaic cell module. According to the invention, the power generation efficiency and matching performance of the photovoltaic cell can be improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, and in particular to a photovoltaic cell interconnection method and a photovoltaic cell module. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Because the output voltage and power of a single photovoltaic cell are limited, it cannot be used directly as a power supply device. Several individual photovoltaic cells must be connected in series or parallel and packaged into a photovoltaic module (PV module) with practical application value. Conventional photovoltaic cells have their positive and negative electrodes on the front and back sides, respectively. Back-contact photovoltaic cells, as a special type of photovoltaic cell, have both their positive and negative electrodes located on the back side. In traditional photovoltaic modules, taking series connection as an example, when connecting photovoltaic cells in a straight path, the main grid lines of the positive electrode of the upper photovoltaic cell are typically welded together. This weld strip is then used as a connection medium to weld to the main grid lines of the negative electrode of the lower photovoltaic cell, thus forming a series unit. When the interconnection path needs to be changed, a busbar is usually used to interconnect the main grid lines of the positive electrode of the upper photovoltaic cell and the negative electrode of the lower photovoltaic cell.

[0004] In other words, in traditional photovoltaic (PV) cell interconnection processes, it is typically necessary to extend solder strips of a certain length from the positive and negative electrodes of two adjacent cell strings, and then connect them with additional busbars to form the electrical connection components between adjacent cell strings. This method of connection results in a high proportion of non-power-generating areas due to the busbars and solder strips occupying a large portion of the cell gaps, thus reducing the area of ​​the effective power-generating components within the PV module and consequently lowering the module's power generation efficiency. Furthermore, with the continuous rise in the prices of raw materials such as PV glass and encapsulant films, and the market's demand and guidance for high module efficiency, it is also necessary to reduce the comparative production costs of interconnected PV modules.

[0005] In addition, considering that photovoltaic system applications require that the positive and negative electrodes of photovoltaic modules be unique, otherwise the application of photovoltaic modules will be greatly limited, traditional interconnection processes mostly use individual series or parallel connections to ensure the uniqueness of the positive and negative electrodes of photovoltaic modules. The lack of a mixed series and parallel interconnection method limits the range of electrical parameters of photovoltaic modules to a certain extent. Summary of the Invention

[0006] To address the shortcomings of the prior art, this invention provides a photovoltaic cell interconnection method and a photovoltaic cell module. By setting a busbar on the positive and negative electrode surfaces of the photovoltaic cells, connecting the busbar to the positive and negative electrode solder strips of adjacent cell strings, a photovoltaic module with parallel, series, or series-parallel interconnection structures can be formed based on this structure. This interconnection method can significantly increase the effective power generation area and efficiency within the photovoltaic module, reduce production costs, and, combined with the series-parallel structure, improve the matching of electrical parameters between the designed photovoltaic module and components such as inverters, thereby enhancing the practicality of the corresponding photovoltaic module.

[0007] In a first aspect, the present invention provides a method for interconnecting photovoltaic cells.

[0008] A photovoltaic cell interconnection method, comprising: A positive electrode busbar is set on the first side edge of the positive electrode surface of the photovoltaic cell, and a negative electrode busbar is set on the second side edge of the negative electrode surface of the photovoltaic cell. The positive electrode busbar and the negative electrode busbar are connected to the positive electrode solder strip and the negative electrode solder strip on the photovoltaic cell, respectively. Connect the positive and negative electrode strips of several adjacent photovoltaic cells to form a photovoltaic cell string A. After rotating 180 degrees, a photovoltaic cell string A' is obtained. Connect the positive busbar of photovoltaic cell string A and the negative busbar of photovoltaic cell string A' in series to form a cell string interconnection unit B. Mirroring the battery string interconnection unit B with the straight line containing the positive and negative output ports as the axis, we obtain the battery string interconnection unit B', which is then connected in parallel to form a parallel structure. By laterally expanding the parallel structure, several parallel structures are obtained. These are then connected in series to form a series-parallel structure. Each structure is then encapsulated to obtain a photovoltaic cell module.

[0009] In a further technical solution, the first and second sides of the photovoltaic cell are symmetrical sides of the photovoltaic cell, and the positive electrode busbar and the negative electrode busbar are perpendicular to the arrangement direction of the positive and negative electrodes and parallel to the first and second sides of the photovoltaic cell, respectively. The positive electrode busbar is used to collect the positive electrode charge of the photovoltaic cell, and the negative electrode busbar is used to collect the negative electrode charge of the photovoltaic cell.

[0010] In a further technical solution, the photovoltaic cell includes a conventional photovoltaic cell and a back-contact photovoltaic cell; For conventional photovoltaic cells, the positive electrode busbar and negative electrode busbar are overlapped with the positive electrode solder strip and negative electrode solder strip on the conventional photovoltaic cell, respectively, and the overlap length is not less than half the width of the busbar. For back-contact photovoltaic cells, when the busbar collects charges of the same polarity, it is made to interconnect with only a single polarity electrode by at least one of the following methods: local insulation of the back-contact photovoltaic cell surface, local insulation of the solder ribbon, and local insulation of the busbar surface.

[0011] A further technical solution is to define the width and thickness of the positive and negative busbars according to actual needs when the busbars are connected in series, and to define the first distance range between the edge of the positive busbar and the edge of the adjacent photovoltaic cell, and the second distance range between the edge of the negative busbar and the edge of the second side; the first distance range is set to be greater than the second distance range.

[0012] A further technical solution involves interconnecting to form a battery string interconnection unit B, including: For several adjacent photovoltaic cells, the positive electrode solder strip of the previous photovoltaic cell is connected to the negative electrode solder strip of the next adjacent photovoltaic cell, and so on, to form a photovoltaic cell string A. Photovoltaic cell string A is rotated 180 degrees to obtain photovoltaic cell string A'; Set the string spacing between two photovoltaic cell strings, and connect them in series with the positive busbar of photovoltaic cell string A and the negative busbar of photovoltaic cell string A' as the interconnection terminal to form cell string interconnection unit B; In the battery string interconnection unit B, the negative busbar of photovoltaic cell string A serves as the negative output port, and the positive busbar of photovoltaic cell string A' serves as the positive output port, with the positive and negative output ports on the same horizontal straight line.

[0013] In a further technical solution, in the battery string interconnection unit B, the end of the positive and negative busbars that are close to each other but not connected is used as an extension port. A bypass diode is connected to the extension port to provide bypass protection for the battery string interconnection unit.

[0014] Further technical solutions, interconnected to form a parallel structure, include: By mirroring the line containing the positive and negative output ports of battery string interconnection unit B as the axis, we obtain battery string interconnection unit B'. Set the spacing between the two battery string interconnection units, then connect the two battery string interconnection units in parallel, and after encapsulation, form a photovoltaic module with a parallel structure; Specifically, the two battery string interconnection units are connected in parallel as follows: the negative busbar of battery string interconnection unit B is simultaneously connected to the negative solder strips of the two battery string interconnection units, and the positive busbar of battery string interconnection unit B is simultaneously connected to the positive solder strips of the two battery string interconnection units.

[0015] A further technical solution involves interconnecting components to form a series-parallel structure, which is then packaged to obtain photovoltaic modules, including: By horizontally expanding the parallel structure, several parallel structures are obtained; Connect the positive and negative output ports of several parallel structures in sequence to form a series-parallel structure; The positive output port of the first parallel structure and the negative output port of the last parallel structure are used as the positive and negative output ports of the series-parallel photovoltaic module. Junction boxes with bypass diodes, positive and negative output cables and connectors are set at the positive and negative output ports. Junction boxes with only bypass diodes are set at the extension ports in the straight line where the positive and negative output ports are located. After encapsulation, a photovoltaic module with parallel and series structures is formed.

[0016] Further technical solutions, for non-photovoltaic cell areas, involve optical optimization by using one or more of the following methods on the back of the photovoltaic module: staggered white adhesive film, high reflectivity backsheet, glazed grid glass, and reflective film strip. The non-photovoltaic cell area includes the spacing between cells and the spacing between cell strings.

[0017] Secondly, the present invention provides a photovoltaic cell module.

[0018] A photovoltaic cell module includes a photovoltaic cell module obtained by encapsulating any one of the following structures: a cell string interconnection unit formed by connecting cells using the photovoltaic cell interconnection method described in the first aspect, a parallel structure, or a series-parallel structure.

[0019] The above one or more technical solutions have the following beneficial effects: 1. This invention proposes a photovoltaic cell interconnection method and a photovoltaic cell module. By setting a busbar on the positive and negative electrode surfaces of the photovoltaic cells, the busbar is connected to the positive and negative electrode solder strips led out from the adjacent cell strings. Based on this structure, a photovoltaic module with parallel, series, or series-parallel structures is formed. Through this interconnection method, the effective power generation area and power generation efficiency inside the photovoltaic module can be significantly improved, the production cost can be reduced, and the matching of electrical parameters between the designed photovoltaic module and components such as inverters can be improved by combining the series-parallel structure, thereby improving the practicality of the corresponding photovoltaic module.

[0020] 2. The photovoltaic cell interconnection method proposed in this invention is applicable to conventional photovoltaic cells and back-contact photovoltaic cells. In conventional photovoltaic cells, the lead-out ends of the front-side solder strips of the photovoltaic cells are electrically connected to the main grid solder strips on the back side of the photovoltaic cells to form photovoltaic cell components and photovoltaic modules with series, parallel, and series-parallel connections, thereby increasing the area ratio of the effective power generation region inside the photovoltaic module and the corresponding power generation efficiency of the photovoltaic module. In back-contact photovoltaic cells, methods such as partial insulation of the back-contact photovoltaic cell surface, partial insulation of the solder strips, or partial insulation of the busbar surface are used to electrically interconnect the solder strips on the back side of the back-contact photovoltaic cells and collect specific types of charges, so as to achieve effective interconnection or effective insulation between different back-contact photovoltaic cells. Based on this interconnection method, photovoltaic cell components and photovoltaic modules with series, parallel, and series-parallel connections of back-contact photovoltaic cells are realized, thereby increasing the area ratio of the effective power generation region inside the photovoltaic module and the corresponding power generation efficiency of the photovoltaic module.

[0021] 3. The photovoltaic cell interconnection method designed in this invention is applicable to photovoltaic cell slicing technology using N equal divisions (N is a positive rational number) and unequal division slicing technology; it is also applicable to single-glass photovoltaic modules, double-glass photovoltaic modules and photovoltaic modules using other encapsulation materials and encapsulation processes such as organic polymers.

[0022] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 This is an overall flowchart of the photovoltaic cell interconnection method described in an embodiment of the present invention; Figure 2 This is a schematic diagram of the front and back sides of a conventional photovoltaic cell in an embodiment of the present invention; wherein, ( a () is the front, ( b (This refers to the back side) Figure 3 This is a schematic diagram of the busbar connection between the front and back sides of a conventional photovoltaic cell in an embodiment of the present invention; wherein, ( a () is the front, ( b (This refers to the back side) Figure 4 This is a schematic diagram of a photovoltaic cell string formed by connecting conventional photovoltaic cells in an embodiment of the present invention; Figure 5 This is a schematic diagram of a parallel structure formed by connecting conventional photovoltaic cells in an embodiment of the present invention; Figure 6 This is a schematic diagram of a series-parallel structure formed by connecting conventional photovoltaic cells in an embodiment of the present invention; Figure 7 This is a schematic diagram of the back contact photovoltaic cell and its positive and negative electrode busbar connection in an embodiment of the present invention; Figure 8 This is a schematic diagram of the parallel structure formed by connecting the back-contact photovoltaic cells in an embodiment of the present invention; Figure 9 This is a schematic diagram of a parallel structure formed by connecting back-contact photovoltaic cells and then connecting them in series in an embodiment of the present invention; Figure 10 This is a schematic diagram of the series-parallel structure formed by connecting back-contact photovoltaic cells in an embodiment of the present invention. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are exemplary and are intended only to describe specific embodiments and to provide further explanation of the invention, and are not intended to limit the scope of exemplary embodiments of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] Terminology Explanation Photovoltaic cell: A thin semiconductor wafer that converts sunlight into electrical energy, also known as a solar cell. Typically, the front and back of a photovoltaic cell are the positive and negative electrodes, respectively. Conductive cell meshes are distributed on both the front and back sides, and the cell meshes are usually composed of main grid lines and sub-grid lines.

[0027] Back-contact photovoltaic cell: One of the many types of photovoltaic cells, it is a photovoltaic cell in which both the positive and negative electrodes are located on the back of the cell.

[0028] Main grid lines: fine conductive lines distributed on the surface of photovoltaic cells, generally parallel to the interconnection direction of photovoltaic cell strings, and their main function is to collect charged particles generated by photovoltaic cells under photovoltaic effects; usually, the number and distribution position of main grid lines are the same on the front and back of photovoltaic cells.

[0029] Solder ribbon: A thin wire or strip of conductive material, usually made of metal. It is used to weld adjacent photovoltaic cells to the front and back electrode main grid lines, thereby achieving series connection between them.

[0030] Busbar: A strip-shaped conductive material, typically made of metal. Its primary function is to provide a connection medium for the series connection of the main grid lines of the front electrode of the adjacent photovoltaic cell and the back electrode of the next photovoltaic cell when the interconnection path of the photovoltaic cell string needs to be changed. Its second function is to collect the photogenerated charged particles from the positive and negative electrodes of the photovoltaic cell string and connect them to the corresponding polarity's junction box output port.

[0031] Photovoltaic modules: Components with a basic structure including tempered glass, photovoltaic cells, encapsulation film, backsheet, junction box, positive and negative output cables, etc., are also called solar modules.

[0032] Photovoltaic module power generation efficiency: The ratio of the power generated by a photovoltaic module to the physical area of ​​the photovoltaic module.

[0033] Example 1 This embodiment proposes a photovoltaic cell interconnection method, such as... Figure 1 As shown, the specific steps include: Step S1: Set a positive electrode busbar on the first side edge of the positive electrode surface of the photovoltaic cell, and set a negative electrode busbar on the second side edge of the negative electrode surface of the photovoltaic cell. Connect the positive electrode busbar and the negative electrode busbar to the positive electrode solder strip and the negative electrode solder strip on the photovoltaic cell, respectively. Step S2: Connect the positive and negative electrode strips of several adjacent photovoltaic cells to form a photovoltaic cell string A. After rotating 180 degrees, obtain a photovoltaic cell string A'. Connect the positive busbar of photovoltaic cell string A and the negative busbar of photovoltaic cell string A' in series to form a cell string interconnection unit B. Step S3: Mirror the battery string interconnection unit B with the straight line containing the positive and negative output ports as the axis to obtain the battery string interconnection unit B', and connect them in parallel to form a parallel structure; Step S4: Laterally expand the parallel structure to obtain several parallel structures, connect them in series to form a series-parallel structure, encapsulate each structure to obtain a photovoltaic cell module.

[0034] In this embodiment, taking the application of the interconnection method to conventional photovoltaic cells as an example, the above-mentioned photovoltaic cell interconnection method will be described in more detail. Using the above-mentioned photovoltaic cell interconnection method, for conventional photovoltaic cells, a busbar is set on the back of the photovoltaic cell and connected to the solder strips led out from the front of the adjacent cell string. Based on this structure, a photovoltaic module with parallel, series, or series-parallel structures is formed.

[0035] First, schematic diagrams of the front and back of a conventional photovoltaic cell are shown below. Figure 2 As shown, where, For conventional photovoltaic cells, The solder ribbon connecting the front and back of the photovoltaic cell is a thin filament or strip of conductive material, typically made of metal. Furthermore, the front and back of a conventional photovoltaic cell are the positive and negative electrodes, respectively. The photovoltaic cell technology can include P-type passivated emitter cell technology in crystalline silicon (P-PERC), N-type passivated emitter back-side full diffusion technology (N-PERT), tunneling oxide passivated contact technology (TOPCon), heterojunction technology (HJT), etc. The number of main grids in this conventional photovoltaic cell is unlimited, with typical numbers including 16, 18, 20, 24, and 30.

[0036] In step S1, a busbar is set for a conventional photovoltaic cell, namely: a positive busbar is set on the first side edge of the front of the photovoltaic cell, and a negative busbar is set on the second side edge of the negative side of the photovoltaic cell. The positive busbar and the negative busbar are connected to the positive electrode solder strip and the negative electrode solder strip on the photovoltaic cell, respectively. The positive busbar is used to collect the positive electrode charge of the photovoltaic cell, and the negative busbar is used to collect the negative electrode charge of the photovoltaic cell.

[0037] After setting, such as Figure 3 As shown, For the front electrode of a photovoltaic cell, For the front solder strip of photovoltaic cells, This is the busbar at the interconnection point of the front electrodes of the photovoltaic cell. For the back electrode of a photovoltaic cell, For the back solder strip of photovoltaic cells, This refers to the busbar at the interconnection point on the back of the photovoltaic cell. This busbar is a strip-shaped conductive material, typically made of metal. The first and second sides of the photovoltaic cell are symmetrical sides of the cell. The positive and negative busbars are perpendicular to the arrangement direction of the positive and negative electrodes and parallel to the first and second sides of the photovoltaic cell, respectively.

[0038] Furthermore, to increase the area of ​​photovoltaic cells, reduce the area of ​​non-power generation regions, and reduce the series resistance loss of the busbars, when the busbars are connected in series, the width and thickness of the positive and negative busbars are limited according to actual needs. Simultaneously, a first distance range is defined between the edge of the positive busbar and the edge of the adjacent photovoltaic cell, and a second distance range is defined between the edge of the negative busbar and the second side edge. In this embodiment, a busbar is provided. , The width is 3mm-6mm, and the thickness is 0.27mm-0.35mm; Busbar The distance between the edge of the current collector and the edge of the adjacent photovoltaic cell is 1.5mm-3.5mm. The distance between the edge and the edge of the photovoltaic cell is 0mm-2mm. Additionally, the positive and negative busbars are overlapped with the positive and negative solder strips on conventional photovoltaic cells, respectively. , With solder strip , The overlap length is not less than that of the busbar. 50% of the width.

[0039] In step S2, several conventional photovoltaic cells are interconnected to form a cell string interconnection unit. For example... Figure 4 As shown, firstly, several adjacent photovoltaic cells are electrically connected to each other via solder strips on the front and back sides to form a photovoltaic cell string A. This string A is generally a linear structure, and the number of cells in string A is typically 8-13, but can be adjusted appropriately by combining multi-segmentation and series-parallel structures. The spacing Wc between the cells in string A is typically -1mm to 1.5mm. The two ends of string A are respectively equipped with the aforementioned photovoltaic cell front interconnection busbars. Busbar at the back of the photovoltaic cell Furthermore, battery string A can be used as a standalone photovoltaic power generation unit and formed into photovoltaic module M1 through a certain encapsulation process.

[0040] Next, the photovoltaic cell string A is rotated 180 degrees to obtain the photovoltaic cell string B.

[0041] Then, the string spacing between the two photovoltaic cell strings is set, and the positive busbar of photovoltaic cell string A and the negative busbar of photovoltaic cell string B are connected in series to form a cell string interconnection unit. Specifically, as follows: Figure 5 As shown, C is the interconnection terminal of battery string A and battery string B, and N and P are the positive or negative output ports of the photovoltaic cell string interconnection unit, respectively. The negative busbar of photovoltaic cell string A serves as the negative output port, and the positive busbar of photovoltaic cell string B serves as the positive output port. Battery strings A and B are interconnected through the busbars at the front and back of the photovoltaic cells. , For electrical connection, the spacing Wr between battery strings A and B is typically 1.5mm-2.5mm.

[0042] Furthermore, battery strings A and B are connected via interconnection terminal C to form a battery string interconnection unit, and photovoltaic module M2 is formed by combining photovoltaic module encapsulation materials and encapsulation processes.

[0043] In one implementation, in the battery string interconnection unit, the end where the positive and negative busbars are close to each other but not connected is used as an extension port. A bypass diode is connected to the extension port to provide bypass protection for the battery string interconnection unit.

[0044] In step S3, several battery string interconnect units are connected to form a parallel structure. For example... Figure 5As shown, firstly, M2 is mirrored with the straight line containing output ports N and P as the axis to obtain M2'; secondly, the distance Wh between the photovoltaic cells adjacent to the negative terminals in M2 and M2' is set to 1.5mm-2.5mm, and the busbar is... Simultaneously connect the solder strips on the back of adjacent batteries in M2 and M2', busbar Simultaneously, the solder strips leading out from the front of adjacent cells in M2 and M2' are connected, and a parallel structure is obtained after this parallel connection; then, combined with photovoltaic module encapsulation materials and encapsulation processes, a photovoltaic module M3 with series and parallel structures is formed.

[0045] In step S4, several parallel structures are connected to form a series-parallel structure. For example... Figure 6 As shown, the designed interconnection unit M3 is expanded laterally with output port P as the expansion port to obtain several parallel structures. The positive and negative output ports of the several parallel structures are connected in sequence to form a series-parallel structure. The photovoltaic module is then encapsulated using photovoltaic encapsulation materials and processes such as photovoltaic film, photovoltaic glass or photovoltaic backsheet and aluminum. At the same time, the positive output port of the first parallel structure and the negative output port of the last parallel structure are used as the positive and negative output ports (N and P) of the series-parallel structure photovoltaic module. Junction boxes with bypass diodes and positive and negative output cables and connectors are set at output ports N and P at J1 and JN. Junction boxes with only bypass diodes are set at the expansion port between J1 and JN. Finally, a photovoltaic module M5 with parallel and series structures is formed.

[0046] Through the above interconnection methods, photovoltaic modules with both series and parallel connections can be formed, and the corresponding photovoltaic modules can have practical electrical parameters, thereby improving the matching of the photovoltaic modules with the electrical parameter designs of current inverters and other components on the market. While realizing the electrical series connection, parallel connection, or series-parallel connection of photovoltaic cells, it can also effectively reduce the area ratio of ineffective power generation area (i.e., non-photovoltaic cells formed by the busbar and solder strip) at the interconnection end of the busbar and solder strip, thereby improving the power generation efficiency of the designed photovoltaic modules. In addition, using the solder strip on the back of the cell for the electrical connection of the busbar can reduce the amount of raw materials used for the solder strip to a certain extent, thereby reducing the production cost of photovoltaic modules.

[0047] It should be clarified that the surface morphology of the solder ribbon and busbar can be a smooth physical surface or an optical structure that is conducive to light utilization, so as to further increase the power generation efficiency of the photovoltaic module; the number of solder ribbons is consistent with the number of main grids of the photovoltaic cell, and the solder ribbon is electrically connected to the photovoltaic cell or the main grid electrode position on the back. This connection method is not limited to welding, bonding or other methods; the busbar and the solder ribbon form an electrical connection, and this connection method is not limited to welding, bonding or other methods.

[0048] As one implementation method, for non-photovoltaic cell areas such as the spacing between solar cells and the spacing between solar strings, optical optimization can be achieved by using one or more of the following methods on the back of the photovoltaic module: staggered white adhesive film, high reflectivity backsheet, glazed grid glass, and reflective film strip. This can further improve the power generation efficiency of the photovoltaic module.

[0049] Example 2 This embodiment applies the proposed photovoltaic cell interconnection method to back-contact photovoltaic cells. For back-contact photovoltaic cells where both the positive and negative electrodes are located on the back side, a busbar is formed on the back side of the cell, perpendicular to the arrangement direction of the positive or negative electrodes and parallel to the adjacent sides of the cell. Combined with certain insulation measures, this forms a photovoltaic module with parallel, series, or series-parallel connections of the back-contact photovoltaic cells. This approach increases the effective power generation area and efficiency within the photovoltaic module, and the series-parallel structure further enhances the matching of the electrical parameters between the designed photovoltaic module and its components.

[0050] Taking the application of interconnection methods to back-contact photovoltaic cells as an example, this paper provides a more detailed introduction to photovoltaic cell interconnection methods.

[0051] First, the front and back of the back contact photovoltaic cell are as follows: Figure 7 As shown, , It serves as the positive or negative electrode for the back contact of a photovoltaic cell. Its shape can be designed as multiple continuous linear or strip structures. However, considering cost factors, it is usually designed as multiple discontinuous point structures. This refers to the conductive solder strip used to connect the positive and negative electrodes of adjacent cells Cp and Cn. Furthermore, back-contact photovoltaic cells encompass back-contact photovoltaic cells using different technologies, such as interlocked back-contact (IBC), heterojunction back-contact (HBC), tunneling oxide back-contact (TBC), and back-contact technologies with different interlocking techniques (such as HPBC, HTBC, etc.). The number of electrode grids for the positive or negative electrode of a back-contact photovoltaic cell is unlimited, with typical numbers including 8, 10, 12, 15, and 16.

[0052] In step S1, busbars are set for the back-contact photovoltaic cells. Specifically, a positive busbar is set on the first side edge of the back of the photovoltaic cell, and a negative busbar is set on the second side edge of the back of the photovoltaic cell. The positive and negative busbars are connected to the positive and negative electrode solder strips on the photovoltaic cell, respectively. The positive busbar is used to collect the positive electrode charge of the photovoltaic cell, and the negative busbar is used to collect the negative electrode charge of the photovoltaic cell. When collecting charges of the same polarity, the busbars are interconnected with only a single polarity electrode by at least one of the following methods: partial insulation of the back-contact photovoltaic cell surface, partial insulation of the solder strip, and partial insulation of the busbar surface. Afterwards, several back-contact photovoltaic cells are interconnected to form a cell string interconnection unit.

[0053] After the above connection settings are configured, as follows: Figure 7 As shown, M6 represents the back-contact photovoltaic cell string, with the number of back-contact cells typically ranging from 8 to 13, but this can be adjusted appropriately by combining multi-segmentation and series-parallel structures; B1 is the busbar for collecting the positive electrode charge of the back-contact photovoltaic cells, and B2 is the busbar for collecting the negative electrode charge of the back-contact photovoltaic cells. Specifically, busbar B1, when collecting positive electrode charge, achieves this through localized insulation and soldering of the first back-contact photovoltaic cell surface. By employing methods such as partial insulation or partial insulation of the busbar surface, effective interconnection with the positive electrode solder strip of the first back-contact photovoltaic cell can be achieved while effectively isolating it from the negative electrode solder strip. Similarly, when busbar B2 collects the negative electrode charge of M6, it achieves effective interconnection with the positive electrode solder strip of the back-contact photovoltaic cell through partial insulation of the back-contact photovoltaic cell surface and solder strip... By means of partial insulation or partial insulation of the busbar surface, the negative electrode solder strip of the photovoltaic cell that only contacts the back of the tail cell can be effectively interconnected and effectively insulated from its positive electrode solder strip.

[0054] Furthermore, to increase the area of ​​photovoltaic cells and reduce the area of ​​non-power generation areas, and to reduce the series resistance loss of the busbars, when the busbars are connected in series, the width of the busbars B1 and B2 is set to 3mm-6mm and the thickness to 0.27mm-0.35mm, depending on actual needs. Moreover, when the photovoltaic cells are only connected in series, the distance between the edge of the busbar and the edge of the cell should be 0mm-2mm and perpendicular to the direction of the welding strip.

[0055] In step S2, several conventional photovoltaic cells are interconnected to form a cell string interconnection unit. For example... Figure 8As shown, firstly, M6 is rotated 180 degrees to obtain the back-contact photovoltaic cell string and photovoltaic module power generation unit M7. B1' and B2' are the busbars for the positive and negative electrodes of M2, respectively. Secondly, M6 and M7 are electrically interconnected by busbars B1 and B2' to form a back-contact photovoltaic cell series component. Busbars B1 and B2' can be the same, different, or made of the same material. Then, busbar B2 in M6 and busbar B1' in M7 can serve as the negative and positive output ports of the back-contact photovoltaic cell string, respectively. The ends of the positive and negative busbars that are close to each other but not connected are designated as extension ports, i.e., port J. A bypass diode is connected at this port to provide bypass protection for the formed back-contact photovoltaic cell series component.

[0056] Preferred, such as Figure 9 As shown, based on the back-contact photovoltaic cell series component formed by the electrical interconnection of M6 and M7, series expansion can be further carried out. The number of expanded back-contact photovoltaic cell strings is generally 4-6, thus forming the back-contact photovoltaic cell series component M8. In fact, this step is equivalent to first performing step S4, which horizontally expands and connects the battery string interconnection units, and then performing step S3, which connects the expanded and connected structures in parallel to form a series-parallel structure.

[0057] Specifically, such as Figure 10 As shown, the designed back-contact photovoltaic cell series component M8 is mirrored with the straight line containing output ports N and P as the axis to obtain M8'. Simultaneously, busbars B3, B4, and B5 are electrically interconnected at the mirrored positions of M8 and M8' to obtain the interconnection component M9 of the designed back-contact photovoltaic cell series and parallel structure. Busbars B3, B4, and B5 collect the positive or negative electrode charge of the back-contact photovoltaic cells at the parallel connection ends. When the busbars need to collect the negative electrode charge of the back-contact photovoltaic cells, local insulation and soldering are applied to the surfaces of the back-contact photovoltaic cells on both sides of the busbar at the parallel interconnection point. By means of partial insulation or partial insulation of the busbar surface, it is possible to achieve effective interconnection of the solder strips on the back contact photovoltaic cell surface with only the type of charge to be collected and effective insulation of the solder strips on the opposite electrode.

[0058] Finally, the interconnecting components of the designed back-contact photovoltaic cell series and parallel structure are combined with photovoltaic module encapsulation materials and encapsulation processes. Junction boxes with positive and negative output cables, bypass diodes and connectors are set at the positive output port P and the negative output port N. Junction boxes with only bypass diodes are set at ports similar to point J in the straight line where the positive and negative ports are located. Finally, a back-contact photovoltaic cell photovoltaic module with series and parallel structures is formed.

[0059] It should be clarified that the surface morphology of the solder ribbon and busbar can be a smooth physical surface or an optical structure that is conducive to light utilization, so as to further increase the power generation efficiency of the photovoltaic module; the number of solder ribbons is consistent with the number of main grids of the photovoltaic cell, and the solder ribbon is electrically connected to the photovoltaic cell or the main grid electrode position on the back. This connection method is not limited to welding, bonding or other methods; the busbar and the solder ribbon form an electrical connection, and this connection method is not limited to welding, bonding or other methods.

[0060] Example 3 This embodiment provides a photovoltaic cell module, which includes a photovoltaic cell module obtained by encapsulating any one of the following structures: a battery string interconnection unit, a parallel structure, or a series-parallel structure, formed by connecting the cells using the photovoltaic cell interconnection method described in Embodiment 1 or Embodiment 2.

[0061] The above description is only a preferred embodiment of the present invention. Although the specific implementation of the present invention has been described in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A method for interconnecting photovoltaic cells, characterized in that, include: A positive electrode busbar is set on the first side edge of the positive electrode surface of the photovoltaic cell, and a negative electrode busbar is set on the second side edge of the negative electrode surface of the photovoltaic cell. The positive electrode busbar and the negative electrode busbar are connected to the positive electrode solder strip and the negative electrode solder strip on the photovoltaic cell, respectively. Connect the positive and negative electrode strips of several adjacent photovoltaic cells to form a photovoltaic cell string A. After rotating 180 degrees, a photovoltaic cell string A' is obtained. Connect the positive busbar of photovoltaic cell string A and the negative busbar of photovoltaic cell string A' in series to form a cell string interconnection unit B. Mirroring the battery string interconnection unit B with the straight line containing the positive and negative output ports as the axis, we obtain the battery string interconnection unit B', which is then connected in parallel to form a parallel structure. By laterally expanding the parallel structure, several parallel structures are obtained. These are then connected in series to form a series-parallel structure. Each structure is then encapsulated to obtain a photovoltaic cell module.

2. The photovoltaic cell interconnection method as described in claim 1, characterized in that, The first and second sides of the photovoltaic cell are symmetrical sides of the photovoltaic cell. The positive electrode busbar and the negative electrode busbar are perpendicular to the arrangement direction of the positive and negative electrodes and parallel to the first and second sides of the photovoltaic cell, respectively. The positive electrode busbar is used to collect the positive electrode charge of the photovoltaic cell, and the negative electrode busbar is used to collect the negative electrode charge of the photovoltaic cell.

3. The photovoltaic cell interconnection method as described in claim 2, characterized in that, The photovoltaic cells include conventional photovoltaic cells and back-contact photovoltaic cells; For conventional photovoltaic cells, the positive electrode busbar and negative electrode busbar are overlapped with the positive electrode solder strip and negative electrode solder strip on the conventional photovoltaic cell, respectively, and the overlap length is not less than half the width of the busbar. For back-contact photovoltaic cells, when the busbar collects charges of the same polarity, it is made to interconnect with only a single polarity electrode by at least one of the following methods: local insulation of the back-contact photovoltaic cell surface, local insulation of the solder ribbon, and local insulation of the busbar surface.

4. The photovoltaic cell interconnection method as described in claim 1, characterized in that, When the busbars are connected in series, the width and thickness of the positive and negative busbars are limited according to actual needs. At the same time, the first distance range between the edge of the positive busbar and the edge of the adjacent photovoltaic cell is limited, and the second distance range between the edge of the negative busbar and the edge of the second side is limited; the first distance range is set to be greater than the second distance range.

5. The photovoltaic cell interconnection method as described in claim 1, characterized in that, Interconnection forms battery string interconnection unit B, including: For several adjacent photovoltaic cells, the positive electrode solder strip of the previous photovoltaic cell is connected to the negative electrode solder strip of the next adjacent photovoltaic cell, and so on, to form a photovoltaic cell string A. Photovoltaic cell string A is rotated 180 degrees to obtain photovoltaic cell string A'; Set the string spacing between two photovoltaic cell strings, and connect them in series with the positive busbar of photovoltaic cell string A and the negative busbar of photovoltaic cell string A' as the interconnection terminal to form cell string interconnection unit B; In the battery string interconnection unit B, the negative busbar of photovoltaic cell string A serves as the negative output port, and the positive busbar of photovoltaic cell string A' serves as the positive output port, with the positive and negative output ports on the same horizontal straight line.

6. The photovoltaic cell interconnection method as described in claim 5, characterized in that, In battery string interconnection unit B, the end where the positive and negative busbars are close to each other but not connected is used as an extension port. A bypass diode is connected to the extension port for bypass protection of the battery string interconnection unit.

7. The photovoltaic cell interconnection method as described in claim 1, characterized in that, Interconnection forms a parallel structure, including: By mirroring the line containing the positive and negative output ports of battery string interconnection unit B as the axis, we obtain battery string interconnection unit B'. Set the spacing between the two battery string interconnection units, then connect the two battery string interconnection units in parallel, and after encapsulation, form a photovoltaic module with a parallel structure; Specifically, the two battery string interconnection units are connected in parallel as follows: the negative busbar of battery string interconnection unit B is simultaneously connected to the negative solder strips of the two battery string interconnection units, and the positive busbar of battery string interconnection unit B is simultaneously connected to the positive solder strips of the two battery string interconnection units.

8. The photovoltaic cell interconnection method as described in claim 1, characterized in that, Interconnected to form a series-parallel structure, and encapsulated to obtain photovoltaic modules, including: By horizontally expanding the parallel structure, several parallel structures are obtained; Connect the positive and negative output ports of several parallel structures in sequence to form a series-parallel structure; The positive output port of the first parallel structure and the negative output port of the last parallel structure are used as the positive and negative output ports of the series-parallel photovoltaic module. Junction boxes with bypass diodes, positive and negative output cables and connectors are set at the positive and negative output ports. Junction boxes with only bypass diodes are set at the extension ports in the straight line where the positive and negative output ports are located. After encapsulation, a photovoltaic module with parallel and series structures is formed.

9. The photovoltaic cell interconnection method as described in claim 1, characterized in that, For non-photovoltaic cell areas, optical optimization is achieved by using one or more of the following methods on the back of the photovoltaic module: staggered white adhesive film, high reflectivity backsheet, glazed grid glass, and reflective film strip. The non-photovoltaic cell area includes the spacing between cells and the spacing between cell strings.

10. A photovoltaic cell module, characterized in that, The photovoltaic module includes a photovoltaic cell module obtained by encapsulating any one of the following structures: a battery string interconnection unit, a parallel structure, or a series-parallel structure, formed by connecting the photovoltaic cells using the photovoltaic cell interconnection method described in any one of claims 1-9.

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