Junction box and photovoltaic module

Abstract

The invention relates to a junction box and a photovoltaic module, the junction box comprises a first diode, a second diode, a first wiring terminal, a second wiring terminal and a third wiring terminal, the positive electrode of the first diode is electrically connected with the first wiring terminal; the negative electrode of the first diode, the positive electrode of the second diode and the second wiring terminal are electrically connected; and the cathode of the second diode is electrically connected with the third wiring terminal. The junction box can effectively reduce the influence of faults such as hot spots on the output power of the photovoltaic module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic modules, in particular to a junction box and a photovoltaic module. BACKGROUND

[0002] During the operation of a photovoltaic module, hot spot effect of local heating occurs due to shading, dust or internal failure. The hot spot effect reduces the output power of the photovoltaic module to some extent, and if the heating temperature exceeds a certain limit, it will also cause permanent damage such as dark spots, solder melting, and aging of encapsulation materials, which is an important factor affecting the output power and service life of the photovoltaic module, and may even cause safety hazards.

[0003] To solve the hot spot problem, the mainstream solution is to use a three-part junction box, that is, each photovoltaic module is provided with three junction boxes, and each junction box has a diode that conducts current in one direction when working normally. When hot spot effect occurs in a local area of the photovoltaic module, the diode in the junction box in that area will be broken down to short-circuit the control area of the junction box, thereby reducing the impact on power generation in other normal areas. Currently, the mainstream photovoltaic module has 12 strings of cells, and when one of the junction boxes is broken down due to hot spot problems, it will short-circuit all 4 strings of cells connected to the junction box, resulting in a 1 / 3 reduction in the output power of the photovoltaic module, which has a significant impact on the output power of the photovoltaic module. SUMMARY

[0004] Therefore, it is necessary to provide a junction box and a photovoltaic module to reduce the loss of output power of the photovoltaic module.

[0005] In a first aspect, the present application provides a junction box, comprising a first diode, a second diode, a first terminal, a second terminal and a third terminal, wherein:

[0006] The anode of the first diode is electrically connected to the first terminal;

[0007] The cathode of the first diode and the anode of the second diode are electrically connected to the second terminal;

[0008] The cathode of the second diode is electrically connected to the third terminal.

[0009] The technical solutions are further described as follows:

[0010] In one embodiment, the junction box further comprises a box body, the first diode and the second diode are connected in series and encapsulated in the box body to form a diode package, and the first terminal, the second terminal and the third terminal are arranged around the outer periphery of the diode package.

[0011] In one embodiment, the diode package has a first side and a second side disposed opposite to each other, and a third side connecting the first side and the second side, the first terminal is connected to the first side, the second terminal is connected to the second side, and the third terminal is connected to the third side.

[0012] In one embodiment, the first terminal, the second terminal and the third terminal are each provided with a soldering portion for soldering with a wire.

[0013] In one embodiment, the first terminal, the second terminal and the third terminal are each provided with a threading hole for threading a wire.

[0014] In one embodiment, the first terminal, the second terminal and the third terminal are each provided with a threading hole for threading a wire.

[0015] In one embodiment, the number of the battery string groups is four, the four battery string groups are respectively a first battery string group, a second battery string group, a third battery string group and a fourth battery string group, the first battery string group, the second battery string group, the third battery string group and the fourth battery string group are connected in series, the first battery string group has a negative electrode busbar, the first battery string group and the second battery string group have a first intermediate busbar at a connection position of a positive electrode of the first battery string group and a negative electrode of the second battery string group, the second battery string group and the third battery string group have a second intermediate busbar at a connection position of a positive electrode of the second battery string group and a negative electrode of the third battery string group, the third battery string group and the fourth battery string group have a third intermediate busbar at a connection position of a positive electrode of the third battery string group and a negative electrode of the fourth battery string group, and the fourth battery string group has a positive electrode busbar.

[0016] The number of the junction boxes is two, and the two junction boxes are a negative junction box and a positive junction box. The negative junction box is arranged between the first battery string group and the second battery string group. A first connecting terminal of the negative junction box is connected with the negative busbar. A second connecting terminal of the negative junction box is connected with the first intermediate busbar. A third connecting terminal of the negative junction box is connected with the second intermediate busbar through a first jumper wire. The positive junction box is arranged between the third battery string group and the fourth battery string group. A first connecting terminal of the positive junction box is connected with the second intermediate busbar. A second connecting terminal of the positive junction box is connected with the third intermediate busbar. A third connecting terminal of the positive junction box is connected with the positive busbar through a second jumper wire.

[0017] In one of the embodiments, the first battery string group and the third battery string group are arranged in a first direction of the photovoltaic module. The second battery string group and the third battery string group are arranged between the first battery string group and the third battery string group. The second battery string group and the third battery string group are arranged in a second direction of the photovoltaic module.

[0018] In one of the embodiments, the negative junction box is provided with a negative output terminal connected with the negative busbar. The positive junction box is provided with a positive output terminal connected with the positive busbar.

[0019] In one of the embodiments, each of the battery string groups comprises a plurality of battery strings connected in parallel. Each of the battery strings comprises a plurality of battery pieces connected in series.

[0020] In the above junction box, a first diode and a second diode connected in series are arranged in the junction box. The first connecting terminal is connected with the positive electrode of the first diode. The second connecting terminal is connected with the series connection of the first diode and the second diode. The third connecting terminal is connected with the negative electrode of the second diode. When the junction box is used to connect two battery string groups connected in series, the negative electrode of the first battery string group is connected with the first connecting terminal, the positive electrode of the first battery string group is connected with the second connecting terminal. The negative electrode of the second battery string group is connected with the second connecting terminal, and the positive electrode of the second battery string group is connected with the third connecting terminal. Thus, the first diode is connected in parallel with the first battery string group, and the second diode is connected in parallel with the second battery string group. When one of the two battery string groups connected in series has a hot spot or other faults, only the diode connected in parallel with the battery string group is broken to short-circuit the fault battery string group. The other battery string group and the diode connected in parallel with the battery string group can still work normally, avoiding the problem that all the battery string groups connected with the same junction box are all disabled, thereby reducing the loss of output power of the photovoltaic module. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application and are incorporated herein for a purpose of explanations of the present application and are not intended as improper limitations on the present application.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0023] In addition, the drawings are not drawn in a 1:1 ratio, and the relative sizes of the various elements are only exemplarily drawn in the drawings, but not necessarily drawn in a true ratio. In the drawings:

[0024] Figure 1 Structure schematic view of a positive terminal box of an embodiment.

[0025] Figure 2 Structure schematic view of a negative terminal box of an embodiment.

[0026] Figure 3 Structure schematic view of a photovoltaic module of an embodiment.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 101, negative terminal box; 102, positive terminal box; 11, diode package; 111, first diode; 112, second diode; 121, first terminal; 1211, welding part; 1212, threading hole; 122, second terminal; 123, third terminal; 13, box body; 141, positive output terminal; 142, negative output terminal; 21, first cell string group; 22, second cell string group; 23, third cell string group; 24, fourth cell string group; 31, negative busbar; 32, first intermediate busbar; 33, second intermediate busbar; 34, third intermediate busbar; 35, positive busbar; 41, first jumper wire; 42, second jumper wire. DETAILED DESCRIPTION

[0029] In order to make the above purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. In the following description, a lot of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0030] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0031] In addition, if there are terms such as "first", "second", these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] In the present application, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] In the present application, unless otherwise explicitly specified and limited, if there are similar descriptions such as "first feature on" or "below" the second feature, the meaning can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0034] It is to be noted that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it is to be understood that when a layer is referred to as being "connected", "coupled", or "supported" on another layer or substrate, it can be directly on the other layer or substrate or intervening layers can also be present. As used herein, the terms "vertical", "horizontal", "up", "down", "left", "right", and the like are described with respect to the orientations shown in the drawings and are merely for purposes of illustration and are not intended to be limiting.

[0035] Specifically, one embodiment of the present application provides a junction box for connecting two battery string groups in series in a photovoltaic module. Specifically, referring to Figure 1 The junction box of one embodiment includes a first diode 111, a second diode 112, a first terminal 121, a second terminal 122, and a third terminal 123, wherein the positive electrode of the first diode 111 is electrically connected to the first terminal 121; the negative electrode of the first diode 111, the positive electrode of the second diode 112, and the second terminal 122 are electrically connected; and the negative electrode of the second diode 112 is electrically connected to the third terminal 123.

[0036] In the above junction box, the first diode 111 and the second diode 112 are arranged in series in the junction box, the first terminal 121 is connected to the positive electrode of the first diode 111, the second terminal 122 is connected to the series connection of the first diode 111 and the second diode 112, and the third terminal 123 is connected to the negative electrode of the second diode 112. In this way, when the junction box is used to connect two battery string groups in series, the negative electrode of the first battery string group is connected to the first terminal 121, the positive electrode of the first battery string group is connected to the second terminal 122, the negative electrode of the second battery string group is connected to the second terminal 122, and the positive electrode of the second battery string group is connected to the third terminal 123, so that the first battery string group and the first diode 111 form a parallel connection, and the second battery string group and the second diode 112 form a parallel connection. When one of the two battery string groups in series has a hot spot or other fault, only the diode in parallel with the fault battery string group is broken down to short-circuit the fault battery string group, and the other battery string group and the diode in parallel with it can still work normally, avoiding the problem that all battery string groups connected by the same junction box fail, thereby reducing the loss of output power of the photovoltaic module.

[0037] Referring to Figure 1In an embodiment, the junction box further comprises a box body 13, the first diode 111 and the second diode 112 are connected in series and encapsulated in the box body 13 to form a diode package 11, and the first junction terminal 121, the second junction terminal 122 and the third junction terminal 123 are arranged around the outer periphery of the diode package 11. By connecting the first diode 111 and the second diode 112 in series and encapsulating them in one box body 13, the number of junction boxes can be reduced under the corresponding circuit design, the circuit structure is simplified, and the cost is saved. At the same time, by arranging the first junction terminal 121, the second junction terminal 122 and the third junction terminal 123 around the outer periphery of the diode package 11, the internal layout of the junction box can be more regular, and the volume of the box body 13 can be reduced.

[0038] Optionally, in an embodiment, the diode package 11 has a first side and a second side arranged opposite to each other, and a third side connecting the first side and the second side, the first junction terminal 121 is connected to the first side, the second junction terminal 122 is connected to the second side, and the third junction terminal 123 is connected to the third side. Specifically, the first side corresponds to the positive electrode of the first diode 111, so as to ensure that the first junction terminal 121 can be directly connected to the positive electrode of the first diode 111. The second side corresponds to the negative electrode of the first diode 111 and the positive electrode of the second diode 112, so as to ensure that the second junction terminal 122 can be directly connected to the negative electrode of the first diode 111 and the positive electrode of the second diode 112. The third side corresponds to the negative electrode of the second diode 112, so as to ensure that the second junction terminal 122 can be directly connected to the negative electrode of the second diode 112. In this way, the internal wiring of the junction box is simplified, and the regularity of the local part of the internal part of the junction box is further improved.

[0039] Referring to Figure 1 The first junction terminal 121, the second junction terminal 122 and the third junction terminal 123 are each provided with a welding portion 1211 for welding with a wire, so as to facilitate welding and fixing of the first junction terminal 121, the second junction terminal 122 and the third junction terminal 123 with an external wire. The wire includes but is not limited to a busbar or a jumper wire in a photovoltaic module.

[0040] Optionally, in an embodiment, the first junction terminal 121, the second junction terminal 122 and the third junction terminal 123 are each further provided with a threading hole 1212 for threading the wire, and preferably, the threading hole 1212 is formed on one side of the welding portion 1211 close to the diode package 11. Specifically, before welding, the wire is first threaded into the threading hole 1212 to pre-fix the wire, and then the wire is welded with the welding portion 1211, so as to prevent displacement of the wire during welding and improve the welding stability of the wire with the welding portion 1211.

[0041] Optionally, the width of the threading hole 1212 is 0.5mm-5mm, and the length is 2mm-20mm, so as to be compatible with all models of busbars and jumper wires used in the photovoltaic industry.

[0042] Optionally, the first diode 111 and the second diode 112 can be Schottky diodes, MOS tubes or other electronic devices with unidirectional conductivity.

[0043] An embodiment of the present application also provides a photovoltaic module, specifically, the photovoltaic module of an embodiment comprises at least two electric cell string groups connected in series, and the junction box of any one of the preceding embodiments, the junction box is arranged between the two electric cell string groups connected in series, and in the two electric cell string groups connected in series, the negative electrode of one of the electric cell string groups is electrically connected to the first junction terminal 121 of the junction box, the positive electrode of the other electric cell string group is electrically connected to the third junction terminal 123 of the junction box, and the series connection of the two electric cell string groups is electrically connected to the second junction terminal 122 of the junction box.

[0044] In the above photovoltaic module, when the two electric cell string groups connected in series are connected by the junction box, the negative electrode of the first electric cell string group is connected to the first junction terminal 121, and the positive electrode of the first electric cell string group is connected to the second junction terminal 122; the negative electrode of the second electric cell string group is connected to the second junction terminal 122, and the positive electrode of the second electric cell string group is connected to the third junction terminal 123, so that the first electric cell string group and the first diode 111 form a parallel connection, and the second electric cell string group and the second diode 112 form a parallel connection. When one of the two electric cell string groups connected in series has a hot spot or other faults, only the diode in parallel with the faulty electric cell string group is broken down to short-circuit the faulty electric cell string group, and the other electric cell string group and the diode in parallel with it can still work normally, avoiding the problem that all the electric cell string groups connected by the same junction box are all disabled, thereby reducing the loss of output power of the photovoltaic module.

[0045] Specifically, referring to Figure 3 In an embodiment, the number of electric cell string groups is four, the four electric cell string groups are a first electric cell string group 21, a second electric cell string group 22, a third electric cell string group 23 and a fourth electric cell string group 24, the first electric cell string group 21, the second electric cell string group 22, the third electric cell string group 23 and the fourth electric cell string group 24 are connected in series, the negative electrode of the first electric cell string group 21 is led out by a negative busbar 31, the series connection of the positive electrode of the first electric cell string group 21 and the negative electrode of the second electric cell string group 22 is led out by a first intermediate busbar 32, the series connection of the positive electrode of the second electric cell string group 22 and the negative electrode of the third electric cell string group 23 is led out by a second intermediate busbar 33, the series connection of the positive electrode of the third electric cell string group 23 and the negative electrode of the fourth electric cell string group 24 is led out by a third intermediate busbar 34, and the positive electrode of the fourth electric cell string group 24 is led out by a positive busbar 35.

[0046] Correspondingly, the number of junction boxes is two, and the two junction boxes are a negative junction box 101 and a positive junction box 102. The negative junction box 101 is arranged between the first battery string group 21 and the second battery string group 22. The first connecting terminal 121 of the negative junction box 101 is connected with the negative busbar 31. The second connecting terminal 122 of the negative junction box 101 is connected with the first intermediate busbar 32. The third connecting terminal 123 of the negative junction box 101 is connected with the second intermediate busbar 33 through the first cross-over line 41. The positive junction box 102 is arranged between the third battery string group 23 and the fourth battery string group 24. The first connecting terminal 121 of the positive junction box 102 is connected with the second intermediate busbar 33. The second connecting terminal 122 of the positive junction box 102 is connected with the third intermediate busbar 34. The third connecting terminal 123 of the positive junction box 102 is connected with the positive busbar 35 through the second cross-over line 42.

[0047] Specifically, through the above-mentioned circuit design, the first battery string group 21 and the first diode 111 of the negative junction box 101 form parallel connection, the second battery string group 22 and the second diode 112 of the negative junction box 101 form parallel connection, the third battery string group 23 and the first diode 111 of the positive junction box 102 form parallel connection, and the fourth battery string group 24 and the second diode 112 of the positive junction box 102 form parallel connection. Thus, when one of the four battery string groups fails, for example, the first battery string group 21 fails, the first diode 1211 of the negative junction box 101 will be broken down to short-circuit the first battery string group 21. At the same time, the second battery string group 22 connected with the negative junction box 101 still works normally, and the third battery string group 23 and the fourth battery string group 24 connected with the positive junction box 102 also work normally. That is, the photovoltaic module only loses 1 / 4 of the output power. Compared with the traditional photovoltaic module which loses 1 / 3 of the output power when one diode is broken down, the photovoltaic module of the present application can effectively reduce the influence of hot spot and other faults on the output power of the photovoltaic module.

[0048] In addition, compared with the traditional three-part junction box photovoltaic module scheme which needs to use three junction boxes of different specifications, the photovoltaic module of the present application can effectively protect all the battery string groups through two junction boxes (the positive junction box 102 and the negative junction box 101) of the same specification, thereby saving the number of junction boxes, unifying the specifications of the junction boxes, and reducing the production cost.

[0049] Optionally, in an embodiment, the first battery string group 21 and the third battery string group 23 are arranged in a first direction of the photovoltaic module, the second battery string group 22 and the third battery string group are arranged between the first battery string group 21 and the third battery string group 23, and the second battery string group 22 and the third battery string group are arranged in a second direction of the photovoltaic module. In this way, the battery string groups can be arranged more regularly and orderly in the photovoltaic module, thereby improving the output power of the photovoltaic module per unit area. Specifically, as shown in the arrow S1 direction is the first direction, and the arrow S2 direction is the second direction. Exemplarily, the first direction can be the length direction of the photovoltaic module, and the second direction can be the width direction of the photovoltaic module. Figure 1

[0050] Optionally, each battery string group includes a plurality of parallel battery strings, and each battery string includes a plurality of series-connected cell pieces. Specifically, the plurality of cell pieces in each battery string are connected in series in the first direction, and the plurality of battery strings in each battery string group are connected in parallel in the second direction.

[0051] As shown in Figure 1 , in an embodiment, the first battery string group 21 and the third battery string group 23 are symmetrically arranged and each include 6 battery strings, and each battery string includes 3 cell pieces. The second battery string group 22 and the fourth battery string group 24 are symmetrically arranged and each include 3 battery strings, and each battery string includes 6 cell pieces, i.e. Figure 1 The photovoltaic module version shown in the example is 72 cell pieces. Understandably, in other embodiments, the photovoltaic module version can also be 54, 60, 66, 78 cell pieces, etc.

[0052] Exemplarily, the type of cell piece can be a half-piece cell, a three-piece cell, a four-piece cell, or a five-piece cell, etc., which is not limited here. Exemplarily, the technical type of cell piece can be PERC, HJT, BC, etc., which is not limited here.

[0053] Referring to Figure 1 and Figure 2 , in an embodiment, the negative terminal box 101 is provided with a negative output end 142, the negative output end 142 is connected with the negative bus bar 31, that is, the negative output end 142 is connected with the first terminal 121 of the negative terminal box 101, and the negative output end 142 is used as the negative electrode of the photovoltaic module. The positive terminal box 102 is provided with a positive output end 141, the positive output end 141 is connected with the positive bus bar 35, that is, the positive output end 141 is connected with the third terminal 123 of the positive terminal box 102, and the positive output end 141 is used as the positive electrode of the photovoltaic module.

[0054] ​Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, it is to be understood that the application embraces all such possible combinations.

[0055] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A terminal block, characterized by The junction box comprises a first diode (111), a second diode (112), a first terminal (121), a second terminal (122) and a third terminal (123), wherein: the positive electrode of the first diode (111) is electrically connected with the first terminal (121); the negative electrode of the first diode (111), the positive electrode of the second diode (112) and the second terminal (122) are electrically connected; the negative electrode of the second diode (112) is electrically connected with the third terminal (123).

2. The junction box of claim 1, wherein, The junction box further comprises a box body (13), the first diode (111) and the second diode (112) are connected in series and encapsulated in the box body (13) to form a diode package (11), and the first terminal (121), the second terminal (122) and the third terminal (123) are arranged around the outer periphery of the diode package (11).

3. The junction box of claim 2, wherein, The diode package (11) has a first side and a second side arranged oppositely, and a third side connecting the first side and the second side, the first terminal is connected to the first side, the second terminal (122) is connected to the second side, and the third terminal (123) is connected to the third side.

4. The junction box of claim 1, wherein, The first terminal (121), the second terminal (122) and the third terminal (123) are each provided with a welding portion (1211) for welding with a wire.

5. The junction box of claim 1, wherein, The first terminal (121), the second terminal (122) and the third terminal (123) are each provided with a threading hole (1212) for threading a wire.

6. A photovoltaic module, characterized by, The junction box comprises at least two battery string groups connected in series and the junction box of any one of claims 1-5, the junction box is arranged between the two battery string groups connected in series, and in the two battery string groups connected in series, the negative electrode of one of the battery string groups is electrically connected with the first terminal (121) of the junction box, the positive electrode of the other battery string group is electrically connected with the third terminal (123) of the junction box, and the series connection of the two battery string groups is electrically connected with the second terminal (122) of the junction box.

7. The photovoltaic module of claim 6, wherein, The number of the battery string groups is four, and the four battery string groups are a first battery string group (21), a second battery string group (22), a third battery string group (23) and a fourth battery string group (24) respectively, the first battery string group (21), the second battery string group (22), the third battery string group (23) and the fourth battery string group (24) are connected in series in sequence, a negative electrode bus bar (31) is led out from the negative electrode of the first battery string group (21), a first intermediate bus bar (32) is led out from the series connection of the positive electrode of the first battery string group (21) and the negative electrode of the second battery string group (22), a second intermediate bus bar (33) is led out from the series connection of the positive electrode of the second battery string group (22) and the negative electrode of the third battery string group (23), a third intermediate bus bar (34) is led out from the series connection of the positive electrode of the third battery string group (23) and the negative electrode of the fourth battery string group (24), and a positive electrode bus bar (35) is led out from the positive electrode of the fourth battery string group (24). The number of the junction boxes is two, and the two junction boxes are a negative electrode junction box (101) and a positive electrode junction box (102) respectively, wherein the negative electrode junction box (101) is arranged between the first battery string group (21) and the second battery string group (22), the first connecting terminal (121) of the negative electrode junction box (101) is connected with the negative electrode bus bar (31), the second connecting terminal (122) of the negative electrode junction box (101) is connected with the first intermediate bus bar (32), and the third connecting terminal (123) of the negative electrode junction box (101) is connected with the second intermediate bus bar (33) through the first cross-over wire (41); the positive electrode junction box (102) is arranged between the third battery string group (23) and the fourth battery string group (24), the first connecting terminal (121) of the positive electrode junction box (102) is connected with the second intermediate bus bar (33), the second connecting terminal (122) of the positive electrode junction box (102) is connected with the third intermediate bus bar (34), and the third connecting terminal (123) of the positive electrode junction box (102) is connected with the positive electrode bus bar (35) through the second cross-over wire (42).

8. The photovoltaic module of claim 7, wherein, The first battery string group (21) and the third battery string group (23) are arranged in a first direction of the photovoltaic module, the second battery string group (22) and the third battery string group are arranged between the first battery string group (21) and the third battery string group (23), and the second battery string group (22) and the third battery string group are arranged in a second direction of the photovoltaic module.

9. The photovoltaic module of claim 7, wherein, The negative electrode junction box (101) is provided with a negative electrode output end (142) connected with the negative electrode bus bar (31), and / or the positive electrode junction box (102) is provided with a positive electrode output end (141) connected with the positive electrode bus bar (35).

10. The photovoltaic module of claim 6, wherein, Each of the battery string groups comprises a plurality of battery strings connected in parallel, and each of the battery strings comprises a plurality of solar cell pieces connected in series.

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