Photovoltaic module and photovoltaic system

Abstract

The present application relates to a photovoltaic module and a photovoltaic system. The photovoltaic module comprises a first battery pack (100) comprising a first battery string (102) and a second battery string (104), wherein a positive electrode of the first battery string (102) is connected to a negative electrode of the second battery string (104); a second battery pack (200) comprising a third battery string (202) and a fourth battery string (204), wherein a negative electrode of the third battery string (202) is connected to a positive electrode of the fourth battery string (204); and a first middle busbar (300), a second middle busbar (400) and a third middle busbar (500) which are spaced apart, wherein the first middle busbar (300) is connected to a negative electrode of the first battery string (102), the second middle busbar (400) is connected to a positive electrode of the third battery string (202), the third middle busbar (500) is separately connected to a positive electrode of the second battery string (104) and a negative electrode of the fourth battery string (204).

Description

Photovoltaic panels and photovoltaic systems

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 2023229441859, filed on November 1, 2023, entitled “Photovoltaic Modules and Photovoltaic Systems,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of photovoltaics, and in particular to a photovoltaic module and a photovoltaic system. Background Art

[0004] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0005] Typically, when two battery strings connected in series in a photovoltaic module are reverse-parallel connected at the ends of different bypass diodes, the ends of each battery string are respectively connected to different bus bars in the photovoltaic module, and then the bus bars are connected to the ends of the bypass diodes in the junction box to achieve reverse parallel connection between the battery strings and the bypass diodes. This process is complicated.

[0006] Summary of the Invention

[0007] According to various embodiments of the present application, a photovoltaic assembly and a photovoltaic system are provided.

[0008] The present disclosure provides a photovoltaic module, comprising:

[0009] A first battery pack includes a first battery string and a second battery string, wherein the positive electrode of the first battery string is connected to the negative electrode of the second battery string;

[0010] a second battery pack, comprising a third battery string and a fourth battery string, wherein the negative electrode of the third battery string is connected to the positive electrode of the fourth battery string; and

[0011] The first central bus bar, the second central bus bar and the third central bus bar are arranged at intervals, the first central bus bar is connected to the negative electrode of the first battery string, the second central bus bar is connected to the positive electrode of the third battery string, and the third central bus bar is respectively connected to the positive electrode of the second battery string and the negative electrode of the fourth battery string.

[0012] The present disclosure also provides a photovoltaic system, comprising:

[0013] A photovoltaic module as described in any one of the above items; and

[0014] The junction box includes a first bypass element and a second bypass element; the positive electrode of the first bypass element is connected to the first middle bus bar, the negative electrode of the second bypass element is connected to the second middle bus bar, and the negative electrode of the first bypass element and the positive electrode of the second bypass element are connected to the third middle bus bar.

[0015] The details of one or more embodiments of the present disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0017] FIG1 is a schematic structural diagram of a photovoltaic module in one embodiment;

[0018] FIG2 is a circuit diagram of a battery pack according to an embodiment of the present invention;

[0019] FIG3 is a schematic structural diagram of a photovoltaic module in another embodiment;

[0020] FIG4 is a circuit diagram of a battery pack according to an embodiment of the present invention; FIG3;

[0021] FIG5 is a schematic structural diagram of a photovoltaic system in one embodiment;

[0022] FIG6 is a circuit diagram of a battery pack according to an embodiment of the present invention; FIG5;

[0023] FIG7 is a schematic structural diagram of a photovoltaic system according to another embodiment;

[0024] FIG8 is a circuit diagram of a battery pack according to an embodiment of the present invention.

[0025] Explanation of the reference numerals: 100, first battery group; 102, first battery string; 104, second battery string; 106, solar cell; 108, first end bus bar; 200, second battery group; 202, third battery string; 204, fourth battery string; 206, second end bus bar; 300, first middle bus bar; 302, first bypass element; 304, second bypass element; 400, second middle bus bar; 500, third middle bus bar; 600, junction box; 700, photovoltaic module. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0029] It will be understood that the terms "first," "second," and the like used herein may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, a first battery pack may be referred to as a second battery pack, and similarly, a second battery pack may be referred to as a first battery pack without departing from the scope of this application. Both the first battery pack and the second battery pack are battery packs, but they are not the same battery pack.

[0030] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0031] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.

[0032] FIG1 is a schematic diagram of the structure of a photovoltaic module in an embodiment, and FIG2 is a circuit diagram of the circuit connection of a battery pack in an embodiment corresponding to FIG1 . As shown in FIG1 and FIG2 , in this embodiment, a photovoltaic module is provided, including: a first battery pack 100, a second battery pack 200, a first middle bus bar 300, a second middle bus bar 400, and a third middle bus bar 500; the first battery pack 100 includes a first battery string 102 and a second battery string 104, wherein the positive electrode of the first battery string 102 is connected to the negative electrode of the second battery string 104; the second battery pack 200 The battery pack includes a third battery string 202 and a fourth battery string 204, wherein the negative electrode of the third battery string 202 is connected to the positive electrode of the fourth battery string 204; a first central bus bar 300, a second central bus bar 400, and a third central bus bar 500 are arranged at intervals, wherein the first central bus bar 300 is connected to the negative electrode of the first battery string 102, the second central bus bar 400 is connected to the positive electrode of the third battery string 202, and the third central bus bar 500 is connected to the positive electrode of the second battery string 104 and the negative electrode of the fourth battery string 204, respectively.

[0033] Specifically, the first cell string 102 is formed by a plurality of solar cells 106 connected in series. The positive electrode of any solar cell 106 located in the middle of the first cell string 102 is connected to the negative electrode of an adjacent solar cell 106, and the negative electrode of the solar cell 106 is also connected to the positive electrode of another adjacent solar cell 106. The positive electrode of the solar cell 106 located at one end of the first cell string 102 is not connected to the adjacent solar cell 106 and serves as the positive electrode of the first cell string 102. The negative electrode of the solar cell 106 located at the other end of the first cell string 102 is not connected to the adjacent solar cell 106 and serves as the negative electrode of the first cell string 102. The second cell string 104, the third cell string 202, and the fourth cell string 204 are similar and are not described in detail here.

[0034] The positive electrode of the first battery string 102 is connected to the negative electrode of the second battery string 104, so that the first battery string 102 and the second battery string 104 in the first battery group 100 are connected in series. At this time, the negative electrode of the first battery string 102 is the negative electrode of the first battery group 100, and the positive electrode of the second battery string 104 is the positive electrode of the first battery group 100; the negative electrode of the third battery string 202 is connected to the positive electrode of the fourth battery string 204, so that the third battery string 202 and the fourth battery string 204 in the second battery group 200 are connected in series. At this time, the positive electrode of the third battery string 202 is the positive electrode of the second battery group 200, and the negative electrode of the fourth battery string 204 is the negative electrode of the second battery group 200.

[0035] The first middle bus bar 300 , the second middle bus bar 400 and the third middle bus bar 500 are spaced apart so that any two of the first middle bus bar 300 , the second middle bus bar 400 and the third middle bus bar 500 are disconnected from each other and do not directly contact each other. The first central bus bar 300 is connected to the negative electrode of the first battery string 102, and the negative electrode of the first battery group 100 is led out through the first central bus bar 300. The second central bus bar 400 is connected to the positive electrode of the third battery string 202, and the positive electrode of the second battery group 100 is led out through the second central bus bar 400. The third central bus bar 500 is respectively connected to the positive electrode of the second battery string 104 and the negative electrode of the fourth battery string 204. The positive electrode of the first battery group 100 and the negative electrode of the second battery group 100 are connected together through the third central bus bar 500 to realize the series connection of the first battery group 100 and the second battery group 100. At the same time, the positive electrode of the first battery group 100 and the negative electrode of the second battery group 200 can be led out through a third central bus bar 500, thereby reducing the use of bus bars and reducing production costs. Subsequently, the first battery group 100 can be reverse-connected in parallel to the two ends of the first bypass element 302 via the first central bus bar 300 and the third central bus bar 500. The first bypass element 302 can prevent the solar cells 106 in the first battery group 100 from being burned due to the hot spot effect. The second battery group 200 can be reverse-connected in parallel to the two ends of the second bypass element 304 via the second central bus bar 400 and the third central bus bar 500. The second bypass element 304 can prevent the solar cells 106 in the second battery group 200 from being burned due to the hot spot effect. Furthermore, reverse-connecting the first battery group 100 and the second battery group 200 at the two ends of different bypass elements can prevent the reverse current passing through the bypass element from exceeding the reverse current limit of the bypass element and damaging the bypass element. At the same time, it increases the current of the photovoltaic module, reduces the difficulty of matching the photovoltaic module with the inverter, and reduces the voltage of the photovoltaic module while keeping the number of solar cells in the photovoltaic module unchanged.

[0036] Illustratively, the first bypass element 302 and / or the second bypass element 304 include a bypass diode or an integrated circuit with a bypass protection function. The bypass protection refers to protecting batteries connected in reverse parallel at both ends without affecting normal use of the batteries.

[0037] In the above-mentioned photovoltaic module, the third central bus bar 500 realizes the series connection between the first battery group 100 and the second battery group 200. At the same time, the first battery group 100 and the second battery group 200 can be reversely connected in parallel at the two ends of different bypass diodes through the first central bus bar 300, the second central bus bar 400 and the third central bus bar 500. The structure is simple, the use of bus bars is reduced, the production cost is reduced, the current of the photovoltaic module is increased, the difficulty of matching the photovoltaic module with the inverter is reduced, and the voltage of the photovoltaic module is reduced while the number of solar cells in the photovoltaic module remains unchanged.

[0038] As shown in Figure 1, in one embodiment, in the first direction X, the first central bus bar 300 is located on one side of the third central bus bar 500, and in the second direction Y, the first central bus bar 300 and the second central bus bar 400 are arranged at intervals. At this time, the first central bus bar 300 and the second central bus bar 400 are located on the same side of the third central bus bar 500, and the second direction intersects with the first direction. This arrangement can reduce the area occupied by the bus bars, facilitate the connection of the first battery pack 100 and the second battery pack 200 to the central bus bars, and the process is simple.

[0039] In one embodiment, in the second direction Y, the first battery group 100 is located on the side of the first central bus bar 300 facing away from the second central bus bar 400, and the second battery group 200 is located on the side of the second central bus bar 400 facing away from the first central bus bar 300. This arrangement facilitates the reverse parallel connection of the first battery group 100 to one side of the first bypass element 302, and the reverse parallel connection of the second battery group 200 to one side of the second bypass element 304. Furthermore, in the first direction X, the first battery string 102 in the first battery group 100 is located on one side of the first central bus bar 300, and the second battery string 104 is located on one side of the third central bus bar 500. This arrangement facilitates connecting the negative electrode of the first battery string 102 to the first central bus bar 300 and the positive electrode of the second battery string 104 to the third central bus bar 500, simplifying the connection method, shortening the length of the connection, and reducing manufacturing costs. Furthermore, in the first direction X, the third battery string 202 in the second battery group 200 is located on one side of the second central bus 400, and the fourth battery string 204 is located on one side of the third central bus 500. This arrangement facilitates connecting the positive pole of the third battery string 202 to the second central bus 400 and connecting the negative pole of the fourth battery string 204 to the third central bus 500, thereby simplifying the connection method, shortening the length of the connection, and reducing the manufacturing cost.

[0040] Furthermore, the first direction X is perpendicular to the second direction Y. This arrangement further reduces the occupied area of ​​the first central bus bar 300, the second central bus bar 400 and the third central bus bar 500, shortens the distance between the first battery pack 100 and the second battery pack 200, reduces the size of the photovoltaic module, increases the integration density of the photovoltaic module, and reduces the manufacturing cost.

[0041] As shown in FIG1 , in one embodiment, the first central bus bar 300 , the second central bus bar 400 and the third central bus bar 500 all extend along the first direction X, thereby reducing the occupied area of ​​the first central bus bar 300 , the second central bus bar 400 and the third central bus bar 500 , shortening the distance between the first battery group 100 and the second battery group 200 , reducing the size of the photovoltaic module, increasing the integration density of the photovoltaic module, and reducing the manufacturing cost.

[0042] Continuing to refer to Figure 1, in one embodiment, the photovoltaic module also includes: a first end bus bar 108 and a second end bus bar 206, the first end bus bar 108 is connected to the positive pole of the first battery string 102 and the negative pole of the second battery string 104; the second end bus bar 206 is connected to the negative pole of the third battery string 202 and the positive pole of the fourth battery string 204, the first end bus bar 108 realizes the series connection of the first battery string 102 and the second battery string 104, and the second end bus bar 206 realizes the series connection of the third battery string 202 and the fourth battery string 204, which simplifies the series connection method between the battery strings in the first battery group 100 and the second battery group 200, and has a simple process and low manufacturing cost.

[0043] FIG3 is a schematic structural diagram of a photovoltaic module according to another embodiment, and FIG4 is a circuit connection diagram of a battery pack according to an embodiment of FIG3 . As shown in FIG3 and FIG4 , in one embodiment, the first battery pack 100 includes a plurality of first battery strings 102 connected in parallel and a plurality of second battery strings 104 connected in parallel. Specifically, all first battery strings 102 in the first battery pack 100 are connected in parallel, and all second battery strings 104 are connected in parallel. The first battery strings 102 connected in parallel and the second battery strings 104 connected in parallel are connected in series. The current of the photovoltaic module can be adjusted by adjusting the number of first battery strings 102 and second battery strings 104 in the first battery pack 100. For example, the number of first battery strings 102 and second battery strings 104 is the same. Furthermore, the second battery group 200 includes a plurality of third battery strings 202 connected in parallel and a plurality of fourth battery strings 204 connected in parallel. Specifically, all third battery strings 202 in the second battery group 200 are connected in parallel, and all fourth battery strings 204 are connected in parallel. The third battery strings 202 connected in parallel and the fourth battery strings 204 connected in parallel are then connected in series. By adjusting the number of third battery strings 202 and fourth battery strings 204 in the second battery group 200, the current of the photovoltaic module can be further adjusted. Exemplarily, the number of third battery strings 202 and fourth battery strings 204 is the same. Furthermore, the sum of the number of first battery strings 102 and third battery strings 202 is equal to the sum of the number of third battery strings 104 and fourth battery strings 204. This configuration maximizes the utilization of the solar cells in the photovoltaic module.

[0044] As shown in Figures 3 and 4, in one embodiment, the sum of the number of solar cells in the first battery string 102 and the number of solar cells in the second battery string 104 is equal to the number of solar cells in the third battery string 202 and the number of solar cells in the fourth battery string 204. At this time, the first battery group 100 and the second battery group 200 can be connected in reverse parallel at both ends of a bypass element with the same performance, eliminating the influence of different bypass elements on the component current transmission of the photovoltaic module, and the selection of the bypass element is simple.

[0045] As shown in Figures 3 and 4, in one embodiment, in the same battery pack, the number of solar cells connected in series in each battery string is the same. Specifically, the number of solar cells in the first battery string 102 in the first battery pack 100 is equal to the number of solar cells in the second battery string 104; the number of solar cells in the third battery string 202 in the second battery pack 20 is equal to the number of solar cells in the fourth battery string 204. This arrangement facilitates the arrangement of solar cells on the battery carrier substrate. Furthermore, the number of solar cells in the first battery string 102, the number of solar cells in the second battery string 104, the number of solar cells in the third battery string 202, and the number of solar cells in the fourth battery string 204 are all the same. Exemplarily, the size of the photovoltaic module in the first direction X is 125mm-210mm, and the size of the photovoltaic module in the second direction Y is 125mm-210mm.

[0046] In one embodiment, the positive electrode of the second battery string 104 is on an extension line of the negative electrode of the fourth battery string 204, and the direction of the extension line is from the second battery string 104 toward the fourth battery string 204, that is, the direction of the extension line is the second direction Y. This reduces the length of the lead wires of the positive electrode of the second battery string 104 and the negative electrode of the fourth battery string 204, improves the utilization rate of raw materials, and reduces manufacturing costs.

[0047] In one embodiment, the solar cells in the photovoltaic module include perovskite / crystalline silicon stacked cells. By adjusting the number of the first cell string 102, the second cell string 104, the third cell string 202 and the fourth cell string 204 in the photovoltaic module and the number of solar cells connected in series in each cell string, the module voltage and module current of the photovoltaic module can be adjusted, so that the photovoltaic module and the inverter corresponding to a typical photovoltaic module including crystalline silicon cells are better matched. Table 1 is a parameter comparison table of a three-parallel, two-series photovoltaic module 3 (similar to FIG3 , except that each cell string in FIG3 has five solar cells), a two-parallel, three-series photovoltaic module 2 including perovskite / crystalline silicon tandem cells (the number of perovskite / crystalline silicon tandem cells connected in series in each cell string is 11), and a two-parallel, three-series photovoltaic module 1 including crystalline silicon cells (the number of crystalline silicon cells connected in series in each cell string is 11). As can be seen from Table 1, compared with photovoltaic module 2, photovoltaic module 3 has lower open-circuit voltage Uoc (V) and operating voltage Umpp (V), higher operating current Impp (A) and short-circuit current Isc (A). The difference between photovoltaic module 3 and photovoltaic module 1 is smaller than that between photovoltaic module 2 and photovoltaic module 1, which makes the inverter matching degree of photovoltaic module 3 higher than that of photovoltaic module 1.

[0048] Table 1

[0049] Figure 5 is a structural schematic diagram of a photovoltaic system in one embodiment, and Figure 6 is a circuit connection diagram of a battery pack in one embodiment corresponding to Figure 5. As shown in Figures 5 and 6, in this example, a photovoltaic system is further provided, including: a photovoltaic module as described in any of the above items and a junction box 600, the junction box 600 including a first bypass element 302 and a second bypass element 304; the positive electrode of the first bypass element 302 is connected to the first middle bus bar 300, the negative electrode of the second bypass element 304 is connected to the second middle bus bar 400, and the negative electrode of the first bypass element 302 and the positive electrode of the second bypass element 304 are connected to the third middle bus bar 500. Bypass protection is respectively implemented for the first battery pack 100 and the second battery pack 200 through the first bypass element 302 and the second bypass element 304 in the junction box 600. At the same time, the junction box 600 can realize external connection of the photovoltaic module to enable the photovoltaic module to provide electrical energy to the outside.

[0050] FIG7 is a schematic diagram of the structure of a photovoltaic system according to another embodiment, and FIG8 is a circuit diagram of the circuit connection of a battery pack according to an embodiment of FIG7 . As shown in FIG7 and FIG8 , in one embodiment, there are multiple photovoltaic modules 700 in the photovoltaic system, and the first central bus bar 700 of any photovoltaic module 700 is connected to the second central bus bar 400 of the adjacent photovoltaic module 700. The first central bus bar 300 of one end photovoltaic module 700 of the two end photovoltaic modules 700 in the photovoltaic system serves as the negative electrode of the photovoltaic system, and the second central bus bar 400 of the other end photovoltaic module 700 serves as the positive electrode of the photovoltaic system. That is, the photovoltaic modules 700 in the photovoltaic system are connected in series through the connection between the first central bus bar 300 and the second central bus bar 400, thereby increasing the system current of the photovoltaic system while preventing the reverse current of the bypass element in the photovoltaic module 700 from exceeding the reverse current limit of the bypass element and damaging the bypass element. Exemplarily, adjacent photovoltaic modules 700 are connected via a junction box. Furthermore, the number of first battery strings 102 , second battery strings 104 , third battery strings 202 and fourth battery strings 204 in each photovoltaic assembly can be set according to system current requirements and the performance of bypass elements in each photovoltaic assembly 700 .

[0051] In one embodiment, the photovoltaic modules 700 in the photovoltaic system have the same structure, thereby eliminating the influence of different photovoltaic modules on the parameters of the photovoltaic system.

[0052] In one embodiment, the junction box 600 includes: a positive terminal, a negative terminal, and a common terminal; the positive terminal is connected to the positive terminal of the first bypass element 302; the negative terminal is connected to the negative terminal of the second bypass element 304; and the common terminal is connected to the negative terminal of the first bypass element 302 and the positive terminal of the second bypass element 304. In this case, the first central bus bar 300 is connected to the positive terminal of the junction box 600, the second central bus bar 400 is connected to the negative terminal of the junction box 600, and the third central bus bar 500 is connected to the common terminal of the junction box. Connections to the third central bus bar 500, the negative terminal of the first bypass element 302, and the positive terminal of the second bypass element 304 are achieved through the common terminal, thereby simplifying the process steps and reducing costs.

[0053] The photovoltaic system includes a photovoltaic module 700, wherein the third central bus bar 500 in the photovoltaic module 700 is connected to the positive electrode of the second battery string 104 and the negative electrode of the fourth battery string 204, respectively. While the third central bus bar 500 realizes the series connection of the first battery group 100 and the second battery group 200, the first battery group 100 can be connected in reverse parallel to the two ends of the first bypass element 302 via the first central bus bar 300 and the third central bus bar 500, and the second battery group 200 can be connected in reverse parallel to the two ends of the second bypass element 304 via the second central bus bar 400 and the third central bus bar 500. This simple structure reduces the use of bus bars and reduces production costs. This increases the current of the photovoltaic module 700 in the photovoltaic system, reduces the difficulty of matching the photovoltaic module with the inverter, and reduces the voltage of the photovoltaic module while maintaining the same number of solar cells in the photovoltaic module.

[0054] Throughout this specification, references to terms such as "some embodiments," "other embodiments," and "desired embodiments" indicate that a particular feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative descriptions of these terms do not necessarily refer to the same embodiment or example.

[0055] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0056] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A photovoltaic module, comprising: A first battery group, comprising a first battery string and a second battery string, wherein a positive electrode of the first battery string is connected to a negative electrode of the second battery string; a second battery group, comprising a third battery string and a fourth battery string, wherein a negative electrode of the third battery string is connected to a positive electrode of the fourth battery string; and The first middle bus bar, the second middle bus bar and the third middle bus bar are arranged at intervals, the first middle bus bar is connected to the negative electrode of the first battery string, the second middle bus bar is connected to the positive electrode of the third battery string, and the third middle bus bar is respectively connected to the positive electrode of the second battery string and the negative electrode of the fourth battery string.

2. The photovoltaic module according to claim 1, wherein in a first direction, the first central bus bar is located on one side of the third central bus bar, and in a second direction, the first central bus bar and the second central bus bar are arranged at intervals, and the second direction intersects with the first direction. 3 . The photovoltaic module according to claim 2 , wherein the first central bus bar, the second central bus bar, and the third central bus bar all extend along the first direction. 4 . The photovoltaic module according to claim 2 , wherein in the second direction, the first battery group is located on a side of the first central bus bar away from the second central bus bar, and the second battery group is located on a side of the second central bus bar away from the first central bus bar. 5 . The photovoltaic assembly according to claim 4 , wherein in the first direction, the first battery string in the first battery group is located on one side of the first middle bus bar, and the second battery string is located on one side of the third middle bus bar. 6 . The photovoltaic module according to claim 2 , wherein the first central bus bar, the second central bus bar, and the third central bus bar all extend along the first direction. The photovoltaic module according to claim 2 , wherein the first direction is perpendicular to the second direction.

8. The photovoltaic module according to claim 1, further comprising: A first end bus bar connected to the positive electrode of the first battery string and the negative electrode of the second battery string; as well as The second end bus bar is connected to the negative electrode of the third battery string and the positive electrode of the fourth battery string.

9. The photovoltaic assembly according to any one of claims 1 to 8, wherein the first battery group comprises a plurality of the first battery strings connected in parallel and a plurality of the second battery strings connected in parallel; and the second battery group comprises a plurality of the third battery strings connected in parallel and a plurality of the fourth battery strings connected in parallel.

10. The photovoltaic module according to any one of claims 1 to 8, wherein in the same battery group, the number of solar cells connected in series in each battery string is the same.

11. The photovoltaic assembly according to any one of claims 1 to 8, wherein the positive electrode of the second battery string is on an extension line of the negative electrode of the fourth battery string, and the direction of the extension line is from the second battery string toward the fourth battery string.

12. The photovoltaic assembly according to any one of claims 1-8, wherein the first middle bus bar and the third middle bus bar connect the first battery group in reverse parallel to both ends of the first bypass element; the second middle bus bar and the third middle bus bar connect the second battery group in reverse parallel to both ends of the second bypass element.

13. A photovoltaic system comprising: The photovoltaic module according to any one of claims 1 to 12; as well as A junction box including a first bypass element and a second bypass element; The positive electrode of the first bypass element is connected to the first middle bus bar, the negative electrode of the second bypass element is connected to the second middle bus bar, and the negative electrode of the first bypass element and the positive electrode of the second bypass element are connected to the third middle bus bar. 14 . The photovoltaic system according to claim 13 , wherein there are a plurality of photovoltaic components, and a first middle bus bar of any photovoltaic component is connected to a second middle bus bar of an adjacent photovoltaic component.

15. The photovoltaic system according to claim 13, wherein the junction box comprises: a positive terminal connected to the positive electrode of the first bypass element; a negative terminal connected to the negative electrode of the second bypass element; as well as The common end is connected to the cathode of the first bypass element and the anode of the second bypass element.

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