A photovoltaic module

Abstract

The application relates to a photovoltaic module. The photovoltaic module comprises at least two cell units arranged along a first direction and connected in series, each cell unit comprises a plurality of sub-string parallel modules arranged along the first direction and connected in parallel, the sub-string parallel module comprises two cell sub-strings arranged along a second direction, the cell sub-string comprises a plurality of cell pieces connected in series, the cell piece adopts a 2-split cell piece or a multi-split cell piece, the second direction is parallel to the installation plane of the photovoltaic module, and the first direction is perpendicular to the second direction. The photovoltaic module provided by the embodiment of the application can have long-term safety and reliability in a complex shading environment.

Description

Technical Field

[0001] This application relates to the field of photovoltaic power generation technology, and in particular to a photovoltaic module. Background Technology

[0002] In large-scale photovoltaic power plants and distributed (industrial, commercial, and residential) scenarios, shading between rows of photovoltaic modules is difficult to completely avoid. When the cells at the bottom of a photovoltaic module are shaded, the shaded cells will act as a load, consuming the energy generated by the other sun-exposed cells, causing the photovoltaic module to overheat, i.e., producing the "hot spot effect." Traditional photovoltaic modules typically use a bypass diode connected in parallel to the entire cell string for protection. This can lead to reverse bias of the entire cell string due to partial shading in complex shading environments, resulting in a significant reduction in the overall power output of the module. Summary of the Invention

[0003] Therefore, it is necessary to provide a photovoltaic module and a photovoltaic power generation system that can reliably cope with complex shading environments.

[0004] In a first aspect, embodiments of this application provide a photovoltaic module, including at least two battery cells arranged in series along a first direction, each battery cell including a plurality of sub-series-parallel modules arranged in parallel along the first direction.

[0005] The sub-string parallel module includes two battery sub-strings arranged along the second direction. Each battery sub-string includes multiple battery cells connected in series. The battery cells can be 2-cell or multi-cell battery cells.

[0006] The second direction is parallel to the mounting plane of the photovoltaic module, and the first direction is perpendicular to the second direction.

[0007] In some embodiments, the long sides of the solar cells in the photovoltaic module are arranged along a first direction, the length direction of the photovoltaic module is parallel to the first direction, and the following conditions are met simultaneously:

[0008]

[0009]

[0010] Where l and w are the length and width of the solar cell, respectively, and V o V is the open-circuit voltage of the photovoltaic module, v is the output voltage of the solar cell, M is the number of parallel modules in the sub-string of the solar cell, d1 is the spacing between adjacent solar cells along the first direction, s1 is the reserved width of the photovoltaic module along the first direction, d2 is the spacing between adjacent solar cells along the second direction, s2 is the reserved width of the photovoltaic module along the second direction, n is the number of solar cells in the sub-string, and L and W are the length and width of the standardized module, respectively.

[0011] In an exemplary embodiment, the long sides of the solar cells in the photovoltaic module are arranged along a first direction, the length direction of the photovoltaic module is parallel to a second direction, and the following conditions are simultaneously met:

[0012]

[0013]

[0014] Where l and w are the length and width of the solar cell, respectively, and V o V is the open-circuit voltage of the photovoltaic module, v is the output voltage of the solar cell, M is the number of parallel modules in the sub-string of the solar cell, d1 is the spacing between adjacent solar cells along the first direction, s1 is the reserved width of the photovoltaic module along the first direction, d2 is the spacing between adjacent solar cells along the second direction, s2 is the reserved width of the photovoltaic module along the second direction, n is the number of solar cells in the sub-string, and L and W are the length and width of the standardized module, respectively.

[0015] In some embodiments, the component open-circuit voltage V o The voltage range is 40V to 60V, n is 5 to 13, and M is 2 to 6.

[0016] In some embodiments, the number of 2-cell solar cells arranged along the first direction in the photovoltaic module is 8 to 13, and the number of 2-cell solar cells arranged along the second direction is 10 to 26.

[0017] In some embodiments, at least two battery cells are connected in series via a first busbar, and sub-series-parallel modules in the battery cells are connected in parallel via a second busbar.

[0018] In some embodiments, the cross-sectional area of ​​the first busbar is 3–5 mm²; and / or,

[0019] The cross-sectional area of ​​the second busbar is 1.6–2.8 mm².

[0020] In some embodiments, the first busbar and / or the second busbar are disposed on the back side of the battery cell.

[0021] In some embodiments, the width of the first busbar is 15–50 mm and the thickness is 0.1–0.2 mm; and / or,

[0022] The width of the second busbar is 8–28 mm, and the thickness is 0.1–0.2 mm.

[0023] In some embodiments, among at least two battery cells connected in series, adjacent two cells are grouped together, and a bypass diode is connected in parallel in each group. The group of battery cells adjacent to the mounting plane of the photovoltaic module is connected in parallel with a bypass diode.

[0024] Secondly, embodiments of this application provide a photovoltaic power generation system, including the photovoltaic module as described in the first aspect of this application.

[0025] The aforementioned photovoltaic modules offer two key advantages. First, they provide a novel battery circuit topology for complex shading environments. This fundamentally avoids reverse bias in the entire battery string caused by partial shading, preventing a significant reduction in module output power. This transforms "passive bypass protection" into "active circuit avoidance," greatly enhancing the output power of photovoltaic modules in complex shading environments, as well as their long-term safety and reliability. Second, based on this battery circuit topology, the photovoltaic module design integrates various usage scenarios, installation methods, module costs, standardized module dimensions, common cell dimensions, and voltage constraints for integrated and coordinated optimization. This results in a layout with high screen-to-body ratio, optimal material utilization, and compliance with target voltage requirements, maximizing efficiency. Firstly, it improves the output power of the modules, solving the problem of traditional designs where one aspect is neglected for another. It can be used with standardized module sizes and is compatible with various cell sizes, greatly expanding the applicability of this design. Secondly, based on this new cell circuit topology and layout design, the arrangement, size, and setting of the busbars are optimized, reducing bus losses and further improving the screen ratio and module output power. Thirdly, based on this new cell circuit topology, only one bypass diode needs to be connected in parallel for two adjacent series-connected cell units. Based on this, while effectively ensuring the safety and power output of the photovoltaic modules, the amount of diodes and junction boxes used is significantly reduced, thereby simplifying the junction box design and achieving a substantial reduction in the material cost of photovoltaic module manufacturing. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a circuit diagram of a traditional photovoltaic module;

[0028] Figure 2 A circuit diagram of a photovoltaic module provided in an embodiment of this application;

[0029] Figure 3 A circuit diagram of another photovoltaic module provided in an embodiment of this application;

[0030] Figure 4 A circuit diagram of yet another photovoltaic module provided in an embodiment of this application;

[0031] Figure 5 A circuit diagram of yet another photovoltaic module provided in an embodiment of this application;

[0032] Figure 6 This is a circuit diagram of a photovoltaic module from the perspective of the main view, provided as an embodiment of this application. Detailed Implementation

[0033] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0034] Unless otherwise defined, 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 application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0035] It is understood that the terms "first," "second," etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first bus may be referred to as a second bus, and similarly, a second bus may be referred to as a first bus. Both the first bus and the second bus are bus, but they are not the same bus.

[0036] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0037] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0038] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0039] like Figure 1 As shown, the cell arrangement in traditional photovoltaic modules is usually quite simple. The layout design often considers electrical parameters, cell size, or packaging process in isolation. The cell arrangement (horizontal / vertical) is determined solely by manufacturing practices. It adopts a topology structure in which two parallel cell units are arranged vertically, and each cell unit consists of multiple cells connected in series (usually 20-24 or more cells in series). A bypass diode is connected in parallel between every two rows of series cells for protection. This means that in applications where photovoltaic modules are installed vertically, the bottom rows of cells in the rear photovoltaic modules will be blocked by the front photovoltaic modules. At the same time, due to the frame of the photovoltaic modules, dust is prone to accumulate at the bottom, which will also block the bottom cell strings.

[0040] Whether a large area of ​​solar cells is shaded or only a portion of them are shaded, in traditional photovoltaic modules, the entire lower half of the series-connected solar cells becomes a load on the circuit, causing reverse bias and severe localized overheating. This not only results in a significant loss of output power from the photovoltaic module but may also pose a fire hazard. In traditional photovoltaic modules, when solar cells are shaded, they become a load, causing bypass diodes to conduct, such as... Figure 1 As shown, when shading occurs in the bottom row area A1 of the photovoltaic module, the current will only flow through the branch A2 where the bypass diode is located, causing all the cells in the lower half of the traditional photovoltaic module to become loads and unable to output power, which seriously affects the power output of the traditional photovoltaic module.

[0041] Meanwhile, in traditional photovoltaic (PV) modules, one bypass diode is typically configured for every two cell strings. This means that a traditional PV module with 60 or 72 cells usually requires three bypass diodes. For traditional PV modules using multi-cell technology, the number of bypass diodes may increase to six or more. The increased use of bypass diodes leads to a significant increase in the cost of the associated heat dissipation structures and junction boxes for traditional PV modules.

[0042] Based on this, the applicant proposed a photovoltaic module resistant to reverse polarization. For example... Figure 2 As shown, a photovoltaic module 10 of one embodiment includes at least two battery cells 12 arranged and connected in series along a first direction X. Each battery cell 12 includes a plurality of sub-series parallel modules 122 arranged and connected in parallel along the first direction X.

[0043] The photovoltaic module 10 includes four battery cells 12 arranged along a first direction X, numbered from top to bottom as the first battery cell to the fourth battery cell (12-1, 12-2, 12-3, 12-4). The outer sides of the first battery cell 12-1 and the third battery cell 12-3 are positive electrodes, and the outer sides of the second battery cell 12-2 and the fourth battery cell 12-4 are negative electrodes. The four battery cells 12 are connected in series, and current flows from the first battery cell 12-1 to the fourth battery cell 12-4. Each battery cell 12 includes three sub-string parallel modules 122 arranged in parallel along the first direction X. The number of battery cells 12, the positive and negative electrode directions of each battery cell, and the number of sub-string parallel modules 122 are not limited to these and can be determined according to the following multi-factor collaborative design method.

[0044] The sub-string parallel module 122 includes two battery sub-strings 1222 arranged along the second direction Y. Each battery sub-string 1222 includes multiple battery cells 14 connected in series. The battery cells 14 are either 2-cell or multi-cell cells. The second direction Y is parallel to the mounting plane of the photovoltaic module 10, and the first direction X is perpendicular to the second direction Y. Optionally, the second direction Y is horizontal, and the first direction X is perpendicular to the second direction Y.

[0045] The individual battery substrings 1222 in each battery cell 12 are connected in parallel.

[0046] Optionally, the photovoltaic module 10 provided in this application embodiment can be a vertically mounted photovoltaic module or a horizontally mounted photovoltaic module. When the photovoltaic module 10 is a vertically mounted photovoltaic module, the long sides of the solar cells in the photovoltaic module 10 are arranged along a first direction X, and the length direction of the photovoltaic module 10 is parallel to the first direction X. When the photovoltaic module 10 is a horizontally mounted photovoltaic module, the long sides of the solar cells in the photovoltaic module 10 are arranged along the first direction X, and the length direction of the photovoltaic module 10 is parallel to a second direction Y. Optionally, when the photovoltaic module 10 is a photovoltaic module applied to a large-scale ground-mounted power station or a residential photovoltaic module, the photovoltaic module 10 is a vertically mounted photovoltaic module; when the photovoltaic module 10 is an industrial or commercial distributed photovoltaic module, the photovoltaic module 10 is a horizontally mounted photovoltaic module.

[0047] Solar cell 14 is the most basic photoelectric conversion element in photovoltaic module 10, capable of directly converting solar energy into electrical energy. Optionally, solar cell 14 may include monocrystalline silicon solar cells, polycrystalline silicon solar cells, perovskite tandem solar cells, or other types of solar cells. A two-cell solar cell refers to one of two sub-cells formed by cutting a whole solar cell. A multi-cell solar cell refers to one of at least three sub-cells formed by cutting a whole solar cell. Optionally, to ensure high consistency in photovoltaic module 10, all solar cells 14 in photovoltaic module 10 are of the same type. Using two-cell or multi-cell solar cells helps to reduce the output current of photovoltaic module 10 and increases the open-circuit voltage of photovoltaic module 10.

[0048] In the photovoltaic module of this application embodiment, each cell includes six independent parallel branches, forming six independent current paths. The on / off state of one branch or path does not affect other branches or paths. If a certain area of ​​the cell module is shaded, causing the branch corresponding to the shaded area to stop working, since the cell sub-strings of each cell in the photovoltaic module of this application embodiment are connected in parallel, whether the branch corresponding to the shaded area works or not does not affect the branches corresponding to other areas. The branches corresponding to other unshaded areas still generate power and output power normally. For example, suppose the bottom row of cells in the fourth cell unit at the bottom of the photovoltaic module is shaded, causing the bottommost sub-string parallel module to stop generating power. However, since the three sub-string parallel modules in the fourth cell unit are connected in parallel, the other two sub-string parallel modules still generate power normally. The current can be output without passing through the bottommost sub-string parallel module. Therefore, the bottommost sub-string parallel module being shaded and unable to work normally does not affect the other sub-string parallel modules, and the cell unit to which it belongs can still output power.

[0049] Therefore, the photovoltaic module provided in this application adopts a novel battery circuit topology. By using a parallel structure of multiple battery sub-strings and arranging the parallel sub-string battery modules in a direction perpendicular to the module installation direction, multiple independent current paths can be constructed at the photovoltaic module 10 level. Each battery cell 12 can have a large number of independent current paths. This ensures that in any area of ​​the photovoltaic module 10 that may be shaded (exemplarily, especially the bottom row of the photovoltaic module 10), there are parallel current paths to choose from. This avoids the problem of the entire string failing due to partial shading. It can minimize the number of battery cells 14 that experience reverse bias heating, while maximizing the number of independent current paths that can still work normally. This ensures that the photovoltaic module 10 maintains the maximum possible power output even under partial shading conditions, significantly improving the output power of the photovoltaic module 10 under different complex shading environments, solving the safety risks caused by hot spot effects, and achieving anti-reverse bias.

[0050] The photovoltaic module 10 provided in this application embodiment has an innovative design of the battery circuit topology of the photovoltaic module, which can fundamentally avoid the reverse bias phenomenon of all battery sub-strings 1222 caused by partial shading from the physical connection, changing "passive bypass protection" to "active circuit avoidance", and greatly improving the long-term safety and reliability of the photovoltaic module in complex shading environment.

[0051] In the photovoltaic module design, the following key constraints are simultaneously optimized and solved: installation and shading constraints, electrical system constraints, and standardized manufacturing constraints.

[0052] First, determine the application scenarios and installation methods for photovoltaic modules. Application scenarios include large-scale ground-mounted power plants, industrial and commercial distributed systems, and residential systems.

[0053] Secondly, the shading pattern, standardized module size, and cell type and size are determined based on the usage scenario and installation method. Large-area bottom shading and partial shading are common shading patterns in large-scale ground-mounted power plants, industrial and commercial distributed systems, and residential applications. Standard manufacturing constraints include standardized module sizes and common cell sizes. For large-scale ground-mounted power plants, standardized module sizes include 2384mm×1303mm, 2382mm×1134mm, etc.; cell sizes include 195×90~140mm, preferably 195×91mm, 195×105mm, or 195×110mm; vertical installation is adopted. For residential applications, standardized module sizes include 1762mm×1134mm; cell sizes include 210mm×105mm. For industrial and commercial applications, standardized module sizes include 2384mm×1303mm or 2382mm×1134mm, and cell sizes include 210mm×105mm or 182mm×105mm; horizontal mounting is used. Cell types include crystalline silicon cells, perovskite cells, or perovskite-crystalline silicon tandem cells, etc.

[0054] Third, the battery circuit topology is determined based on the shading mode. The battery circuit topology of the anti-reverse-bias photovoltaic module adopted in the above embodiments of this application can effectively solve the problems of large-area shading and localized shading at the bottom of the photovoltaic module.

[0055] Fourth, based on the electrical design parameters of the photovoltaic module and the type of solar cells, a multi-factor collaborative design method is used to determine the photovoltaic module layout. Electrical system constraints include open-circuit voltage and cell breakdown voltage.

[0056] For vertically mounted photovoltaic modules, the long sides of the solar cells 14 in the photovoltaic module 10 are arranged along the first direction X, the length direction of the photovoltaic module 10 is parallel to the first direction X, and the following conditions are met simultaneously (first set of calculation formulas):

[0057]

[0058]

[0059] Where l and w are the length and width of the battery cell 14, respectively, and V o V is the open-circuit voltage of the photovoltaic module 10, v is the output voltage of the cell 14, M is the number of sub-string parallel modules 122 in the battery cell 12, d1 is the spacing between adjacent cells 14 along the first direction X, s1 is the reserved width of the photovoltaic module 10 along the first direction X, d2 is the spacing between adjacent cells 14 along the second direction Y, s2 is the reserved width of the photovoltaic module 10 along the second direction Y, n is the number of cells 14 in the battery sub-string 1222, and L and W are the length and width of the standardized module, respectively.

[0060] For the horizontally mounted photovoltaic module, the long side of the solar cells 14 in the photovoltaic module 10 is arranged along the first direction X, the length direction of the photovoltaic module 10 is parallel to the second direction Y, and the following conditions are met simultaneously (second set of calculation formulas):

[0061]

[0062]

[0063] Where l and w are the length and width of the battery cell 14, respectively, and V o V is the open-circuit voltage of the photovoltaic module 10, v is the output voltage of the cell 14, M is the number of sub-string parallel modules 122 in the battery cell 12, d1 is the spacing between adjacent cells 14 along the first direction X, s1 is the reserved width of the photovoltaic module 10 along the first direction X, d2 is the spacing between adjacent cells 14 along the second direction Y, s2 is the reserved width of the photovoltaic module 10 along the second direction Y, n is the number of cells 14 in the battery sub-string 1222, and L and W are the length and width of the standardized module, respectively.

[0064] Finally, determine the busbar size and configuration, as well as the bypass diode configuration.

[0065] In traditional photovoltaic (PV) module design, electrical parameters such as voltage, cell size, or module packaging technology are often considered in isolation. This leads to a situation where cells are simply connected in series to meet voltage requirements, neglecting the possibility of reverse bias due to shading in different installation scenarios. Furthermore, the cell arrangement direction (horizontal or vertical) is determined solely by manufacturing practices and has no relation to shading resistance logic. Moreover, in designing large-size PV modules, it is difficult to simultaneously meet voltage requirements and high power targets within the standard PV module size framework, often resulting in compatibility issues or low material utilization.

[0066] The multi-factor integrated collaborative design method provided in this application integrates the installation method, shading mode, cell size, cell type, open-circuit voltage, photovoltaic module size, and circuit topology of the photovoltaic module during the photovoltaic module layout design. In addition to fundamentally solving the above-mentioned hot spot reverse bias problem of photovoltaic modules, it can also obtain photovoltaic modules 10 with the highest screen ratio, optimal material utilization, and target open-circuit voltage, thus achieving the optimal synergistic effect between photovoltaic module cost and performance.

[0067] The output voltage of a single solar cell is 0.5–3V. For crystalline silicon solar cells, the output voltage of a single solar cell is 0.4–0.7V; for perovskite-crystalline silicon tandem solar cells, the output voltage of a single solar cell is 1.5–2V; and for three-cell perovskite solar cells, the output voltage of a single solar cell is 2.8–3V.

[0068] Optionally, the reserved width s1 or s2 is related to factors such as creepage distance and waterproof adhesive width. d2 is -0.3 to 2 mm; when using a lamination process, the spacing d2 is negative. d1 is 0-10 mm.

[0069] In some embodiments, the open-circuit voltage Vo of the photovoltaic module 10 is 40V to 60V. The avalanche breakdown voltage of perovskite cells is approximately 1V to 4V, while the avalanche breakdown voltage of crystalline silicon cells is higher than 70V. For perovskite tandem cells, the reverse bias voltage is mainly applied to the crystalline silicon bottom cell. Controlling the open-circuit voltage Vo of the photovoltaic module between 40V and 60V can prevent the photovoltaic module 10 using perovskite-crystalline silicon tandem cells from experiencing breakdown and overheating under reverse bias.

[0070] When using perovskite-silicon tandem solar cells with two-cell modules, the aforementioned multi-factor collaborative design method, specifically the two sets of calculation formulas, yields a cell count (n) of 5–13 cells per sub-string and a number of parallel sub-string modules (M) of 2–6 cells per cell unit. The number of two-cell modules arranged along the first direction X is 8–13, and the number of two-cell modules arranged along the second direction Y is 10–26. This approach can cover various scenarios, including large-scale ground-mounted power plants, industrial and commercial applications, and residential applications. It is also compatible with standardized module sizes and various commonly used cell specifications, achieving the highest screen-to-body ratio, optimal material utilization, and a series of standardized layouts that meet target voltage requirements. This solves the problem of traditional designs that compromise on certain aspects, and improves the applicability of the aforementioned battery circuit topology and design method.

[0071] The following describes the photovoltaic module layout for various application scenarios, using perovskite crystalline silicon tandem cells, with the cells being 2-cell units arranged vertically.

[0072] Example 1: High-density power plant design

[0073] In large-scale ground-mounted power station scenarios, a vertical mounting method is adopted. The photovoltaic modules adopt a standard size of 2384mm × 1303mm. The cell size is 195mm × 91mm or 195mm × 105mm, arranged vertically. A stacking process is used, and the spacing between adjacent cells 14 along the second direction Y is -1.5mm. The module open-circuit voltage is 40~60. The circuit topology adopts the battery circuit topology of the above embodiment.

[0074] In this embodiment, as Figure 3 As shown, L=2384mm, W=1303mm, l=195mm, w=91mm or 105mm. Using the first set of calculation formulas, the number of battery cells is 4, the number of sub-string parallel modules in each battery cell is 3, the number of battery cells in each sub-string parallel module is 7, the module output voltage is 56V, and the total number of 2-segment battery cells is 168.

[0075] This embodiment achieves an optimal balance between power and safety. Utilizing the novel battery circuit topology described above, it resolves the hot spots caused by bottom shading of the photovoltaic modules during vertical installation, achieves anti-reverse bias, boasts a screen-to-body ratio of up to 94.6%, and maximizes output power within a standard size framework.

[0076] Example 2: Standard Power Plant Layout

[0077] In the large-scale ground-mounted power station scenario, a vertical mounting method is adopted. The photovoltaic modules adopt a standard size of 2382mm × 1134mm. The cell size is 195mm × 91mm or 195mm × 110mm, arranged vertically. The spacing between adjacent cells 14 along the second direction Y is 0.5mm. The open-circuit voltage of the module is 40~60. The circuit topology adopts the battery circuit topology of the above embodiment.

[0078] In this embodiment, as Figure 3 As shown, L=2382mm, W=1134mm, l=195mm, w=91mm or 110mm. Using the first set of calculation formulas, the number of battery cells is 4, the number of sub-string parallel modules in each battery cell is 3, the number of battery cells in each sub-string parallel module is 7, the module output voltage is 48V, and the total number of 2-segment battery cells is 144.

[0079] This embodiment balances performance and cost. Utilizing the novel battery circuit topology described above, it resolves the hot spots caused by bottom shading of the photovoltaic modules during vertical installation, achieving anti-reverse bias. With a screen-to-body ratio of 92.6%, it offers greater flexibility in manufacturing processes and a more competitive cost while maintaining extremely high safety. It maximizes output power within a standard size framework.

[0080] Example 3: Household-compatible template, solving compatibility issues under standard household sizes.

[0081] For residential applications, a vertical mounting method is adopted. The photovoltaic modules use a standard size of 1762mm × 1134mm. The solar cells are 210mm × 105mm in size and arranged vertically. A stacking process is used, with the spacing between adjacent solar cells 14 along the second direction Y being -0.50 to 2mm. The open-circuit voltage of the module is 40 to 60V. The circuit topology adopts the battery circuit topology of the above embodiment.

[0082] In this embodiment, as Figure 4 As shown, L=1762mm, W=1134mm, l=210mm, w=105mm. Using the first set of calculation formulas, the number of battery cells is 4, the number of sub-string parallel modules in each battery cell is 2, the number of battery cells in each sub-string parallel module is 5, the module output voltage is 40V, and the total number of 2-segment battery cells is 80.

[0083] The novel battery circuit topology described above solves the problem of hot spots caused by bottom shading of photovoltaic modules during vertical installation, achieving anti-reverse bias and improving the safety and reliability of the modules. This topology is compatible with different cell sizes, thus having a wider range of applications.

[0084] Example 4: Industrial and Commercial Version 1

[0085] For commercial and industrial rooftop applications, a horizontal mounting method is used. The photovoltaic modules are of standard size 2384mm × 1303mm. The solar cells are 210mm × 105mm in size and arranged vertically. A stacking process is used, with the spacing between adjacent solar cells 14 along the second direction Y being -0.3 to 0mm. The open-circuit voltage of the module is 40 to 60V. The circuit topology adopts the battery circuit topology of the above embodiment.

[0086] In this embodiment, as Figure 5 As shown, L=2384mm, W=1303mm, l=210mm, w=105mm. Using the second set of calculation formulas, the number of battery cells is 2, the number of sub-string parallel modules in each battery cell is 3, the number of battery cells in each sub-string parallel module is 11, the module output voltage is 44V, and the total number of 2-segment battery cells is 132.

[0087] This embodiment features an optimized layout for horizontal mounting, maintaining high power output and resistance to shading. The novel battery circuit topology described above solves the problem of hot spots caused by bottom shading of photovoltaic modules during horizontal installation, achieving reverse bias resistance and improving module safety and reliability. This topology's applicability can be extended from vertical to horizontal mounting, offering a wider range of applications.

[0088] Example 5: Industrial and Commercial Version Two

[0089] For commercial and industrial rooftop applications, a horizontal mounting method is used. The photovoltaic modules are of standard size 2382mm × 1134mm. The solar cells are 182mm × 105mm in size and arranged vertically. A stacking process is used, with the spacing between adjacent solar cells 14 along the second direction Y being -0.3 to 0mm. The open-circuit voltage of the module is 40 to 60V. The circuit topology adopts the battery circuit topology of the above embodiment.

[0090] In this embodiment, as Figure 5 As shown, L=2382mm, W=1134mm, l=182mm, w=105mm. Using the second set of calculation formulas, the number of battery cells is 2, the number of sub-string parallel modules in each battery cell is 3, the number of battery cells in each sub-string parallel module is 11, the module output voltage is 44V, and the total number of 2-segment battery cells is 132.

[0091] This embodiment features an optimized layout for horizontal mounting, maintaining high power output and resistance to shading. The novel battery circuit topology addresses the hot spots caused by bottom shading of the photovoltaic module during horizontal installation, achieving reverse bias resistance and improving module safety and reliability. This topology's applicability extends from vertical to horizontal mounting and is compatible with next-generation silicon wafer sizes (182mm × 105mm), offering a wider range of applications.

[0092] Comparative Example 1:

[0093] use Figure 1 The circuit topology shown is a traditional series connection at the bottom of the photovoltaic module. The module size is 2384mm × 1303mm, and the cell size is 210mm × 105mm. The total number of 2-section cells is 132. It is installed vertically. The cells are arranged horizontally. Each string has a bypass diode connected in parallel.

[0094] Comparative Example 2:

[0095] use Figure 1 The circuit topology shown is a traditional series connection at the bottom of the photovoltaic module. The module size is 2384mm × 1303mm, and the cell size is 210mm × 105mm. The total number of 2-section cells is 132. It is installed vertically. The cells are arranged vertically. Each string has a bypass diode connected in parallel.

[0096] The photovoltaic modules 10 of the five different types provided in this application (vertical high-density type, vertical standard type, residential adapter type, horizontal type (210 2-cell), horizontal type (210R 2-cell)) are compared with traditional photovoltaic modules as shown in Table 1 below.

[0097] Table 1

[0098]

[0099] Module degradation rate under IEC61215 hot spot test conditions:

[0100] Taking the vertically mounted photovoltaic module provided in Embodiment 1 of this application as an example, according to the test method given in IEC61215-2:2021 4.9.5.2, the anti-reverse polarization vertically mounted photovoltaic module provided in this application embodiment, as well as the lowest and highest shunt resistance cells of traditional vertically mounted photovoltaic modules, were selected. The worst-case shading condition for each test unit was determined, causing the photovoltaic module 10 to be short-circuited under temperature conditions of 55±5℃ and 1000W / m 2 The solar cells were irradiated for 1 hour under the specified radiation conditions, and the results were compared. Table 2 shows the comparison results. (During the test, one solar cell was shaded. It is assumed that the shading location of a traditional photovoltaic module is as follows...) Figure 1The boxed area shown represents the battery cell BAT1, and the shading portion of the photovoltaic module provided in this embodiment is as follows. Figure 2 The selected area shown is the battery cell BAT2.

[0101] Table 2

[0102]

[0103] In one exemplary embodiment, such as Figure 6 As shown, at least two battery cells 12 are connected in series via a first busbar 22, and the sub-string parallel modules 122 in the battery cells 12 are connected in parallel via a second busbar 24. In the battery circuit topology of this embodiment, each battery cell 12 includes multiple parallel battery sub-strings, which causes a sharp increase in the current in the busbar, placing higher demands on the current-carrying capacity of the busbar.

[0104] In some embodiments, the cross-sectional area of ​​the first busbar 22 is 3–5 mm², enabling it to carry a current of 20–30 A. The cross-sectional area of ​​the second busbar 24 is 1.6–2.8 mm², enabling it to carry a current of 10–15 A. This significantly improves the current-carrying capacity of the busbars, preventing the photovoltaic modules from overheating due to excessive current and thus avoiding safety hazards, further enhancing the safety of the photovoltaic modules.

[0105] Optionally, the resistivity of the first bus 22 or the second bus 24 is 0.0172 Ω·mm² / m.

[0106] Taking Example 1 as an example, if the current of a single string of tandem cells is taken as the median value, calculated at 4A, the current through the first busbar 22 is 24A, and the line loss of the first busbar 22 is 2.47~4.12W. The current through the second busbar 24 is 12A, and the line loss of the second busbar 24 is 2.2W~3.85W. In contrast, the cross-sectional area of ​​the first busbar 2 of a conventional photovoltaic module is 1.6~2.4mm², and the line loss when carrying the current of the aforementioned tandem cells is 5.13~7.71W. The cross-sectional area of ​​the second busbar of a conventional photovoltaic module is 1.0~1.6mm², and the line loss when carrying the current of the aforementioned tandem cells is 3.85~6.16W.

[0107] Taking Example 4 as an example, the cross-sectional area of ​​the first busbar 22 needs to be set at 3~5mm², with a line loss of 1.24~2.06W; the cross-sectional area of ​​the second busbar 24 needs to be set at 1.6~2.8mm², with a line loss of 1.28W~2.2W. In contrast, the traditional second busbar has a cross-sectional area of ​​1.0~1.6mm², with a line loss of 1.93~3.08W; and the traditional first busbar has a cross-sectional area of ​​1.6~2.4mm², with a line loss of 2.56~3.84W.

[0108] Therefore, in Example 1, compared with the traditional busbar, the busbar of this application can reduce the average current loss of a single module by more than 5W. In Example 4, the busbar of this application can reduce the average current loss of a single module by more than 2W. This significantly reduces the power loss of the busbar and further improves the output power of the photovoltaic module.

[0109] Optionally, the first busbar 22 is located at the middle position of the photovoltaic module 10; the second busbar 24 is located at the edge position of the photovoltaic module 10 along the second direction Y.

[0110] In some embodiments, the width of the first busbar 22 is 15–50 mm and the thickness is 0.1–0.2 mm. The width of the second busbar 24 is 8–28 mm and the thickness is 0.1–0.2 mm. Optionally, the width of the first busbar 22 is 40 mm and the thickness is 0.1 mm, and the width of the second busbar 24 is 20 mm and the thickness is 0.1 mm.

[0111] In some embodiments, the first busbar 22 and / or the second busbar 24 are disposed on the back side of the battery cell 14.

[0112] Optionally, at least one of the first busbar 22 and the second busbar 24 is disposed on the back side of the solar cell 14. By disposing of the busbar on the back side of the solar cell, the space occupied by the busbar can be saved for arranging the solar cells, thereby increasing the screen-to-body ratio. When the busbar is disposed on the back side of the solar cell, higher requirements are placed on its thickness. The thickness of the busbar located on the back side of the solar cell 14 is 0.1 to 0.2 mm, which can avoid problems such as localized missing glue and bubbles caused by thickness mismatch within the module.

[0113] When the busbar is located on the front side of the solar cell 14, its thickness is 0.1 to 0.5 mm.

[0114] In some embodiments, optionally, such as Figure 6 As shown, the first busbar 22 and the second busbar 24 are disposed on the back side of the solar cell 14, i.e., the backlight side of the solar cell 14. For example, the first busbar 22 and the second busbar 24 are respectively disposed on the back side of the solar cell 14 by folding. Optionally, an insulating layer 28 is provided on the surface of the busbars near the solar cell 14 to prevent short circuits between each busbar and the corresponding solar cell 14. The thickness of the insulating layer 28 can be less than or equal to 100 μm. The insulating layer can be made of insulating tape.

[0115] The second busbar 24 is welded and fixed to the interconnecting strip 1-2 mm away from the battery cell, with no insulating layer on the contact surface. Busbar 1 is folded towards the back of the battery, with the insulating side in contact with the battery cell. After the first busbar 22 is welded and fixed to the interconnecting strip, it is folded towards the back of the battery cell, while the spacing between the two battery strings gradually decreases to 1-2 mm. Insulating tape separates busbar 2 from the battery cell. This design allows the entire busbar to be hidden behind the battery cell.

[0116] Due to limitations in module design and creepage distance, the width of the second busbar 24 needs to be within 4mm to ensure the creepage distance meets standard requirements, resulting in a thickness of 0.4~0.7mm for the second busbar. If the first busbar is designed conventionally, maintaining a 1~2mm gap with the solar cell, its width needs to be controlled within 6mm, and its thickness will reach 0.5~0.8mm. This busbar thickness easily causes thickness mismatch within the module, leading to problems such as localized adhesive gaps and bubbles. The busbar used in this embodiment solves both the problems of limited width and excessive thickness, while also concealing the busbar, avoiding issues like localized adhesive gaps and bubbles, and improving aesthetics.

[0117] Optionally, the first busbar 22 has a width of 20mm and a thickness of 0.1mm, and the second busbar 24 is disposed between the battery cell strings, 1-2mm away from the battery cells, with a width of 10mm and a thickness of 0.4mm. The first busbar 22 is hidden on the back of the battery by folding, and an insulating layer is provided on the side near the battery cell to prevent short circuits.

[0118] Optionally, after the first busbar 22 is welded to the interconnecting strip, it is folded towards the back of the battery cell. The preferred width is 40mm and the thickness is 0.1mm. The second busbar 24 is disposed at a distance of 1~2mm from the battery cell. The preferred width is 7mm and the thickness is 0.4mm.

[0119] Optionally, the first busbar 22 is disposed 1-2 mm away from the solar cell, preferably with a width of 4 mm and a thickness of 0.4 mm. The busbar 2 is disposed between the solar cell strings, 1-2 mm away from the solar cell, preferably with a width of 6 mm and a thickness of 0.5 mm.

[0120] Taking Example 1 as an example, Table 3 shows a comparison between the busbar of the photovoltaic module 10 provided in this application and the busbar of a conventional photovoltaic module. The average busbar power loss is obtained through theoretical calculation.

[0121] Table 3

[0122]

[0123] As can be seen from Table 3, the busbar of the photovoltaic module 10 provided in this application embodiment, by increasing the width and reducing the thickness, increases the cross-sectional area to improve the current carrying capacity while reducing the average busbar power loss, and its performance is better than that of the busbar of traditional photovoltaic modules.

[0124] Optionally, the photovoltaic module 10 may further include a front glass and a back glass, disposed on the upper and lower sides of the photovoltaic cells. Taking Embodiment 1 as an example, in the photovoltaic module 10, the distance between the second busbar 24 and the left side of the front glass or back glass is 13.5 mm, the width of the second busbar 24 is 4 mm, the distance between the cell 14 located at the top corner of the photovoltaic module 10 and the second busbar 24 is 2 mm, and the distance between the cell 14 located at the top corner of the photovoltaic module 10 and the lower side of the front glass or back glass is 13.5 mm.

[0125] like Figure 6 As shown, the photovoltaic module 10 also includes multiple interconnecting strips 26, electrically connected to the solar cells, for connecting adjacent solar cells in series to collect the photocurrent generated by the solar cells. Finally, it is electrically connected to a busbar to output the collected photocurrent.

[0126] Optionally, a rectangular opening may be provided at the center of the second busbar 24. The width of the rectangular opening may be 3mm to 5mm. The end battery cells of the battery sub-string 1222 and the interconnecting strips 26 of their adjacent battery cells pass through the rectangular opening and are then welded onto the second busbar 24.

[0127] In some embodiments, such as Figure 2 As shown, among the at least two battery cells 12 connected in series, two adjacent cells are grouped together, and a bypass diode 16 is connected in parallel in each group. The group of battery cells 12 adjacent to the mounting plane of the photovoltaic module 10 (i.e., the battery cells located at the bottom of the photovoltaic module) is connected in parallel with a bypass diode 16.

[0128] The bypass diode 16 is used to provide a low-impedance path so that current can bypass the faulty cell when there is a shaded, damaged or degraded cell in the photovoltaic module 10, thereby avoiding hot spot phenomenon of local overheating in the photovoltaic module 10 and ensuring the reliability of the photovoltaic module 10.

[0129] Based on the connection relationship between the bypass diode 16 and the battery cell 12, it is easy to understand that when the photovoltaic module 10 includes only two battery cells 12, the photovoltaic module 10 only needs to use one bypass diode 16; when the photovoltaic module 10 includes four battery cells 12, the photovoltaic module 10 needs two to three bypass diodes 16.

[0130] For example, such as Figure 2As shown, the photovoltaic module includes four cell units 12, including two bypass diodes (16-1 and 16-2). The cathode of the first bypass diode 16-1 is connected to the cathode of each cell sub-string 1222 in the first cell unit 12-1, and the anode of the first bypass diode 16-1 is connected to the anode of each cell sub-string 1222 in the second cell unit 12-2. The cathode of the second bypass diode 16-2 is connected to the cathode of each cell sub-string 1222 in the third cell unit 12-3, and the anode of the second bypass diode 16-2 is connected to the anode of each cell sub-string 1222 in the fourth cell unit 12-4.

[0131] Compared to the traditional photovoltaic module where each string of cells is connected in parallel with a bypass diode, the present application embodiment reduces the number of bypass diodes 16 by about one-third to one-half by connecting two adjacent series-connected cell cells 12 in parallel. This significantly reduces the number of bypass diodes 16, saves junction boxes, and significantly reduces the manufacturing cost of the photovoltaic module 10.

[0132] This application also provides a photovoltaic power generation system, including a photovoltaic module as described in any of the above photovoltaic module embodiments, and further including a photovoltaic inverter.

[0133] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0134] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A photovoltaic module, characterized in that, It includes at least two battery cells arranged in series along a first direction, and each battery cell includes several sub-series-parallel modules arranged in parallel along the first direction. The sub-string parallel module includes two battery sub-strings arranged along the second direction. Each battery sub-string includes multiple battery cells connected in series. The battery cells are either 2-cell or multi-cell battery cells. The second direction is parallel to the mounting plane of the photovoltaic module, and the first direction is perpendicular to the second direction.

2. The photovoltaic module according to claim 1, characterized in that, The long sides of the solar cells in the photovoltaic module are arranged along the first direction, the length direction of the photovoltaic module is parallel to the first direction, and the following conditions are met simultaneously: Where l and w are the length and width of the battery cell, respectively, and V o V is the open-circuit voltage of the photovoltaic module, v is the output voltage of the solar cell, M is the number of parallel sub-string modules in the solar cell, d1 is the spacing between adjacent solar cells along the first direction, s1 is the reserved width of the photovoltaic module along the first direction, d2 is the spacing between adjacent solar cells along the second direction, s2 is the reserved width of the photovoltaic module along the second direction, n is the number of solar cells in the solar sub-string, and L and W are the length and width of the standardized module, respectively.

3. The photovoltaic module according to claim 1, characterized in that, The long sides of the solar cells in the photovoltaic module are arranged along the first direction, the length direction of the photovoltaic module is parallel to the second direction, and the following conditions are met simultaneously: Where l and w are the length and width of the battery cell, respectively, and V o V is the open-circuit voltage of the photovoltaic module, v is the output voltage of the solar cell, M is the number of parallel sub-string modules in the solar cell, d1 is the spacing between adjacent solar cells along the first direction, s1 is the reserved width of the photovoltaic module along the first direction, d2 is the spacing between adjacent solar cells along the second direction, s2 is the reserved width of the photovoltaic module along the second direction, n is the number of solar cells in the solar sub-string, and L and W are the length and width of the standardized module, respectively.

4. The photovoltaic module according to claim 2 or 3, characterized in that, The component open-circuit voltage V o The voltage range is 40V to 60V, n is 5 to 13, and M is 2 to 6.

5. The photovoltaic module according to claim 4, characterized in that, In the photovoltaic module, the number of 2-cell solar cells arranged along the first direction is 8 to 13, and the number of 2-cell solar cells arranged along the second direction is 10 to 26.

6. The photovoltaic module according to claim 1, characterized in that, The at least two battery cells are connected in series via a first busbar, and the sub-series-parallel modules in the battery cells are connected in parallel via a second busbar.

7. The photovoltaic module according to claim 6, characterized in that, The cross-sectional area of ​​the first busbar is 3–5 mm²; and / or, The cross-sectional area of ​​the second busbar is 1.6 to 2.8 mm².

8. The photovoltaic module according to claim 6 or 7, characterized in that, The first busbar and / or the second busbar are disposed on the back side of the battery cell.

9. The photovoltaic module according to claim 6, characterized in that, The width of the first busbar is 15–50 mm, and the thickness is 0.1–0.2 mm; and / or, The width of the second busbar is 8–28 mm, and the thickness is 0.1–0.2 mm.

10. The photovoltaic module according to any one of claims 1-9, characterized in that, In the at least two battery cells connected in series, two adjacent cells are grouped together, and a bypass diode is connected in parallel in each group. The group of battery cells adjacent to the mounting plane of the photovoltaic module is connected in parallel with a bypass diode.

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