Back contact battery assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a back contact cell module and a photovoltaic system. The back contact battery assembly comprises a plurality of parallel connection structures arranged along a first direction, each parallel connection structure comprises two battery string groups arranged along a second direction and a diode, and the two battery string groups are connected with the diode in parallel; each battery string group comprises two battery strings arranged along a first direction, and each battery string comprises a plurality of battery pieces arranged along a second direction; all the battery pieces arranged along the second direction in the parallel structure are connected in an imbricated manner; and the first middle bus bar is positioned on a battery piece, close to one end of a middle line of the parallel structures in the second direction, in the first battery string in the first parallel structure and the second battery string in the second parallel structure. According to the back contact battery assembly and the photovoltaic system provided by the invention, the risk that the edges of the battery pieces are crushed during lamination to cause hidden cracks of the battery pieces can be effectively reduced, and meanwhile, the aesthetic property is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cell, in particular to a back contact cell module and a photovoltaic system. BACKGROUND

[0002] At present, the back contact cell module includes two spaced-apart cell string modules and an intermediate busbar for connecting the two cell string modules in parallel. Since the intermediate busbar is arranged in the spacing area between the two cell string modules, the spacing area cannot well support the intermediate busbar, so that the cell pieces are easily damaged during lamination, and there is a risk of hidden cracks. In addition, due to the existence of the spacing area, the intermediate busbar can be seen from the front of the cell module, that is, there is a blank in the appearance of the cell module, which affects the appearance. CONTENT OF THE UTILITY MODEL

[0003] The present application provides a back contact cell module and a photovoltaic system, aiming to solve the technical problems of increasing the risk of hidden cracks of the cell module and affecting the appearance in the prior art.

[0004] The present application provides a back contact cell module, comprising:

[0005] a plurality of parallel structures arranged along a first direction, each of the parallel structures comprising two cell string groups and a diode arranged along a second direction, the two cell string groups being connected in parallel with the diode; each of the cell string groups comprising two cell strings arranged along the first direction and connected in series, each of the cell strings comprising a plurality of cell pieces arranged along the second direction and connected in series; all the cell pieces arranged along the second direction in the parallel structure being connected in shingled connection;

[0006] a first intermediate busbar extending along the first direction and connecting adjacent first and second parallel structures in series;

[0007] The first intermediate busbar is located in a first cell string in the first parallel structure and a second cell string in the second parallel structure, and is close to the cell pieces at one end of the midline of the parallel structure in the second direction. The first cell string and the second cell string are adjacent cell strings in the first direction.

[0008] In some embodiments, the back contact cell module further comprises a second intermediate busbar;

[0009] The back contact cell module has two edges in the first direction;

[0010] The two edge cell strings close to any of the edges are connected by the second intermediate busbar, and the second intermediate busbar is located on the cell pieces close to one end of the midline of the parallel structure in the second direction in any of the edge cell strings.

[0011] In some embodiments, the back contact battery assembly further comprises an end busbar;

[0012] The end busbar is located on a cell tab of an end of the battery string group away from a center line of the parallel structure in the second direction, and the two battery strings included in the battery string group are connected in series.

[0013] In some embodiments, the back contact battery assembly further comprises a first solder strip and a second solder strip; the first solder strip extends along the second direction and connects two adjacent cell tabs in the battery string, and the second solder strip extends along the second direction and connects two adjacent battery string groups in the second direction.

[0014] In some embodiments, the back contact battery assembly comprises a first insulating strip;

[0015] The first insulating strip extends along the first direction and is arranged between the first intermediate busbar and the back surface of the cell tab corresponding to the first intermediate busbar;

[0016] The first insulating strip is provided with a first through hole for electrical connection of the first intermediate busbar or the solder strip of the corresponding polarity.

[0017] In some embodiments, the back contact battery assembly comprises a second insulating strip;

[0018] The second insulating strip extends along the first direction and is arranged between the second intermediate busbar and the back surface of the cell tab corresponding to the second intermediate busbar;

[0019] The second insulating strip is provided with a second through hole for electrical connection of the second intermediate busbar and the solder strip of the corresponding polarity.

[0020] In some embodiments, the back contact battery assembly comprises a third insulating strip;

[0021] The third insulating strip extends along the first direction and is arranged between the end busbar and the back surface of the cell tab corresponding to the end busbar;

[0022] The third insulating strip is provided with a third through hole for electrical connection of the end busbar and the solder strip of the corresponding polarity.

[0023] In some embodiments, the gap width between two adjacent battery string groups in the first direction is 1mm-3mm.

[0024] In some embodiments, the overlap width of two adjacent cell tabs in the second direction is 0.5mm-1mm.

[0025] The application also provides a photovoltaic system comprising the back contact cell module according to any one of the above.

[0026] The back contact module and the photovoltaic system provided by the application can realize the series connection of the two adjacent parallel structures by arranging the first intermediate busbar on the cell pieces of the two adjacent parallel structures, and the first intermediate busbar can be hidden, the cell pieces arranged in the second direction are all connected in a shingle manner, so that the whole surface of the module presents the appearance effect of complete cell piece splicing, which can not only improve the aesthetic appearance, but also greatly reduce the non-cell space of the module, further increase the light receiving area, and improve the photoelectric conversion efficiency of the module.

[0027] Additional aspects and advantages of the application will be made apparent by the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is one of the structural schematic diagrams of the back contact module provided by the embodiments of the application;

[0029] Figure 2 is another of the structural schematic diagrams of the back contact module provided by the embodiments of the application;

[0030] Figure 3 is a third of the structural schematic diagrams of the back contact module provided by the embodiments of the application;

[0031] Figure 4 is a fourth of the structural schematic diagrams of the back contact module provided by the embodiments of the application;

[0032] Figure 5 is a structural schematic diagram of the photovoltaic system provided by the embodiments of the application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the application more clear, the application will be further described in detail below in combination with the drawings and embodiments. The examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the application, and cannot be understood as limiting the application. In addition, it should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0034] In the description of the present application, it needs to be understood that the terms "upper", "lower", "back", "front", and the like indicate 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 do not indicate or imply 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 a limitation of the present application.

[0035] In the present application, unless otherwise explicitly specified and limited, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "under", "below" and "below" of the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is less than the second feature in horizontal height.

[0036] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the application of other processes and / or the use of other materials.

[0037] The back contact battery assembly and photovoltaic system provided by the embodiments of the present application will be described in detail below in combination with specific embodiments. Figures 1 to 5 The back contact battery assembly and photovoltaic system provided by the embodiments of the present application will be described in detail below in combination with specific embodiments.

[0038] Figure 1 is one of the structural schematic diagrams of the back contact assembly provided by the embodiments of the present application, Figure 2 is one of the structural schematic diagrams of the back contact assembly provided by the embodiments of the present application, Figure 1 and Figure 2 The back contact battery assembly provided by the embodiments of the present application comprises:

[0039] a plurality of parallel structures 10 arranged along a first direction, each parallel structure 10 comprising two battery string groups 101 and a diode 102 arranged along a second direction, the two battery string groups 101 being connected in parallel with the diode 102; each battery string group 101 comprising two battery strings 103 connected in series and arranged along the first direction, each battery string 103 comprising a plurality of battery pieces 104 connected in series and arranged along the second direction; all the battery pieces 104 arranged along the second direction in the parallel structure 10 being connected in a shingled manner;

[0040] a first intermediate busbar 20 extending along the first direction and connecting in series the adjacent first parallel structure and second parallel structure;

[0041] The first intermediate busbar 20 is located in the first battery string in the first parallel structure and the second battery string in the second parallel structure, and is close to the battery piece 104 at one end of the middle line of the parallel structure 10 in the second direction, the first battery string and the second battery string being the battery strings 103 adjacent in the first direction.

[0042] In actual implementation, as shown in Figure 4 , a plurality of battery pieces 104 are arranged along the second direction and connected in series to form a battery string 103, that is, the battery string 103 can be regarded as a whole composed of a plurality of battery pieces connected in series, and each battery string 103 contains the same number of battery pieces.

[0043] As shown in Figure 3 , the battery string group 101 refers to a whole composed of at least two battery strings 103 connected in series along the first direction, and each battery string group 101 contains the same number of battery strings 103, for example, 2 strings, 3 strings, 4 strings or an integer greater than or equal to 2, etc., which is not specifically limited here.

[0044] Among them, the first direction can be the horizontal direction in Figures 1 to 4 , and the second direction can be the vertical direction in Figures 1 to 4 . Of course, in other embodiments, the first direction and the second direction can also be other directions, such as diagonal directions, etc., which are not specifically limited here.

[0045] All the battery pieces 104 arranged along the second direction in a shingled manner means that the battery pieces are arranged in a partially overlapping manner, which can create a series connection structure without gaps between the battery pieces, and the shingled connection mode can fully utilize the surface area of the module, reduce line loss and improve conversion efficiency.

[0046] The two battery string groups 101 are arranged along the second direction and connected in parallel at both ends of the diode 102 to form a parallel structure 10. A plurality of parallel structures 10 can be arranged along the first direction and connected in series through the first intermediate busbar 20.

[0047] In the embodiments of the present application, the two adjacent parallel structures 10 are a first parallel structure and a second parallel structure, and the first parallel structure and the second parallel structure are connected in series through the first intermediate bus bar 20 extending in the first direction;

[0048] It can be understood that, in the first parallel structure and the second parallel structure, there are two groups of first battery strings and second battery strings adjacent in the first direction. The first intermediate bus bar 20 can be located on the cell sheet 104 close to one end of the middle line of the parallel structure 10 in the second direction in the first battery string and the second battery string.

[0049] The first intermediate bus bar 20 is arranged in two cell sheets 104 in which the two battery string groups 101 in the first parallel structure overlap each other, on the back of the cell sheet 104 belonging to the first battery string, and in two cell sheets 104 in which the two battery string groups 101 in the second parallel structure overlap each other, on the back of the cell sheet 104 belonging to the second battery string. For example, the first intermediate bus bar 20 can be arranged at a position substantially in the middle of the two cell sheets 104, away from the fragile edge part, so that the risk of edge damage of the cell sheet 104 and hidden cracks of the cell sheet 104 during lamination can be effectively avoided. Furthermore, the first intermediate bus bar 20 can be arranged on the above-mentioned two cell sheets, and the operability is stronger. In other embodiments, the first intermediate bus bar 20 can also be arranged on the adjacent cell sheets 104 of the above-mentioned two cell sheets 104, which is not limited here.

[0050] The back contact assembly provided in the present application realizes the series connection of the adjacent two parallel structures by arranging the first intermediate bus bar on the cell sheets in which the battery string groups of the adjacent two parallel structures overlap each other, thereby realizing the hiding of the first intermediate bus bar, and the cell sheets arranged in the second direction are all connected in a shingle manner, so that the entire surface of the assembly presents a complete cell sheet splicing appearance effect, which not only improves the aesthetics, but also greatly reduces the non-battery space of the assembly, further increases the light receiving area, and improves the photoelectric conversion efficiency of the assembly.

[0051] In some embodiments, the back contact battery assembly further comprises a second intermediate bus bar 30;

[0052] The back contact battery assembly has two edges in the first direction;

[0053] The two edge battery strings close to any edge are connected through the second intermediate bus bar 30, and the second intermediate bus bar 30 is located on the cell sheet 104 close to one end of the middle line of the parallel structure 10 in the second direction in any edge battery string.

[0054] It can be understood that the two edge battery strings close to any edge are arranged in the second direction, and the second intermediate bus bar 30 is located on the cell sheet 104 in which the two edge battery strings close to any edge overlap each other.

[0055] It should be noted that the second intermediate busbar 30 refers to the busbar with a shorter length relative to the first intermediate busbar 20, that is, the length of the second intermediate busbar 30 is less than the length of the first intermediate busbar 20. In actual implementation, the length of the busbar can be specifically set according to the battery string specification and component specification parameters. The above busbars can be arranged on the back surface of the photovoltaic module at the same time to realize the hiding of the busbar.

[0056] In some embodiments, the back contact battery module further comprises an end busbar 40;

[0057] The end busbar 40 is arranged on the cell sheet 104 at one end of the battery string group away from the center line of the parallel structure 10 in the second direction, and connects two battery strings 103 included in the battery string group 101 in series.

[0058] It can be understood that the end busbar 40 is arranged on the cell sheet at the end of the back contact battery module in the second direction. The back contact battery module has two ends in the second direction, and among all the cell sheets 104 arranged in the first direction at each end, the cell sheets 104 are connected two by two through the end busbar 40 to realize the series connection of the two battery strings 103. The end busbar 40 is arranged on the back surface of the cell sheet 104 at the end, and the hiding of the end busbar 40 can be realized.

[0059] In some embodiments, the back contact battery module further comprises a first solder strip and a second solder strip; the first solder strip extends in the second direction and connects two adjacent cell sheets 104 in the battery string, and the second solder strip extends in the second direction and connects two adjacent battery string groups 101 in the second direction.

[0060] It should be noted that the cell sheets 104 of the battery string 103 can be connected in series by the first solder strip on the back surface. The two parallel battery string groups 101 are connected in parallel by the second solder strip.

[0061] Among them, the first solder strip and the second solder strip can be low-temperature solder strips, or can be ordinary solder strips, or can be other conductive materials.

[0062] In some embodiments, the back contact battery module comprises a first insulating strip;

[0063] The first insulating strip extends in the first direction and is arranged between the first intermediate busbar 20 and the back surface of the cell sheet 104 corresponding to the first intermediate busbar 20;

[0064] The first insulating strip is provided with a first through hole, and the first through hole is used for electrical connection of the first intermediate busbar 20 or the solder strip with the corresponding polarity.

[0065] It can be understood that the first insulating strip is arranged between the first intermediate bus bar 20 and the back surface of the corresponding battery piece 104 of the first intermediate bus bar 20 along the first direction. The welding strip of the corresponding polarity is connected with the first intermediate bus bar 20 through the first through hole or the notch on the first insulating strip, which not only ensures the reliable connection between the welding strip and the bus bar, but also avoids the direct contact between the welding strip and other parts of the photovoltaic module, thereby realizing the double effects of insulation and fixation.

[0066] The first intermediate bus bar 20 and the first insulating strip are both arranged on the back light surface of the back contact battery module along the first direction, and the first intermediate bus bar 20 covers the first insulating strip. From the direction of the back light surface of the back contact battery, the orthographic projection of the first intermediate bus bar 20 is completely located in the orthographic projection of the first insulating strip. The insulating strip can be a long strip similar in shape to the first intermediate bus bar 20. Compared with the need for slotting, segment distribution, punching and other ways to prepare the insulating part, the insulating strip of the embodiment of the application has a simpler process and can save production time.

[0067] In some embodiments, the back contact battery module includes a second insulating strip;

[0068] The second insulating strip extends along the first direction and is arranged between the second intermediate bus bar 30 and the back surface of the corresponding battery piece 104 of the second intermediate bus bar 30;

[0069] The second insulating strip is provided with a second through hole, and the second through hole is used for electrically connecting the second intermediate bus bar 30 and the welding strip of the corresponding polarity.

[0070] It can be understood that the second insulating strip is arranged between the second intermediate bus bar 30 and the back surface of the corresponding battery piece along the first direction. The welding strip of the corresponding polarity is connected with the second intermediate bus bar 30 through the second through hole or the notch on the second insulating strip, which not only ensures the reliable connection between the welding strip and the bus bar, but also avoids the direct contact between the welding strip and other parts of the photovoltaic module, thereby realizing the double effects of insulation and fixation.

[0071] The second intermediate bus bar 30 and the second insulating strip are both arranged on the back light surface of the back contact battery module along the first direction, and the second intermediate bus bar 30 covers the second insulating strip. From the direction of the back light surface of the back contact battery, the orthographic projection of the second intermediate bus bar 30 is completely located in the orthographic projection of the second insulating strip. The insulating strip can be a long strip similar in shape to the second intermediate bus bar 30. Compared with the need for slotting, segment distribution, punching and other ways to prepare the insulating part, the insulating strip of the embodiment of the application has a simpler process and can save production time.

[0072] In some embodiments, the back contact battery module includes a third insulating strip;

[0073] The third insulation strip extends along the first direction and is arranged between the end bus bar 40 and the back surface of the battery sheet 104 corresponding to the end bus bar 40;

[0074] The third insulation strip is provided with a third through hole for electrically connecting the end bus bar 40 and the welding strip of the corresponding polarity.

[0075] It can be understood that the third insulation strip is arranged between the end bus bar 40 and the back surface of the battery sheet 104 corresponding to the end bus bar 40 along the first direction. The welding strip of the corresponding polarity is connected with the end bus bar 40 through the second through hole or the gap on the third insulation strip, which not only ensures the reliable connection between the welding strip and the bus bar, but also avoids the direct contact between the welding strip and other parts of the photovoltaic module, thereby realizing the dual effects of insulation and fixation.

[0076] The end bus bar 40 and the third insulation strip are both arranged along the first direction on the back light surface of the back contact battery module, and the end bus bar 40 covers the third insulation strip. From the direction of the back light surface of the back contact battery, the orthographic projection of the end bus bar 40 is completely located in the orthographic projection of the third insulation strip. The insulation strip can be a long strip similar in shape to the end bus bar 40. Compared with the insulation component which needs to be prepared by slotting, segment distribution, punching and the like, the insulation strip of the embodiment of the application has a simpler process and can save production time.

[0077] In some embodiments, the gap width between two adjacent battery string groups 102 in the first direction is 1mm-3mm.

[0078] It can be understood that a gap needs to be provided between two adjacent battery string groups 102 in the first direction to ensure that the performance of the module is not affected. The gap width can be in the range of 1mm-3mm, for example, it can be 1mm, 1.5mm, 2mm, 2.5mm or 3mm, which is not limited in the embodiment of the application.

[0079] In some embodiments, the overlap width of two adjacent battery sheets in the second direction is 0.5mm-1mm.

[0080] It can be understood that two adjacent battery sheets in the second direction are arranged in a partial overlap, that is, in the parallel structure 10, any two adjacent battery sheets 104 in the second direction overlap a part of the area. For example, the overlap width can be in the range of 0.5mm-1mm, for example, the overlap width can be 0.5mm, 0.6mm, 0.7mm, 0.9mm, 0.9m or 1mm, which is not limited in the embodiment of the application. Without affecting the reliability of the module, the smaller the overlap width, the smaller the non-battery area of the module, which effectively improves the light receiving area of the module, thereby improving the photoelectric conversion efficiency of the module.

[0081] In the embodiments of the present application, the plurality of solar cells in the back contact battery assembly can be sequentially connected in series to form a cell string, thereby realizing the series connection of the current, for example, the connection of the cell pieces can be realized by means of welding strip (bus bar, interconnecting strip), conductive back plate, etc.

[0082] It can be understood that in such embodiments, the back contact battery assembly can further include a metal frame, a back plate, photovoltaic glass and a film. The film can be filled between the front and back of the solar cell and the photovoltaic glass, adjacent cell pieces, etc., as a filler, which can be a transparent gel with good light transmission and aging resistance, for example, the film can use EVA film or POE film, which can be selected according to actual conditions, and is not limited herein.

[0083] The photovoltaic glass can be covered on the film on the front of the solar cell, and the photovoltaic glass can be super white glass, which has high light transmittance, high transparency, and superior physical, mechanical and optical properties, for example, the light transmittance of super white glass can reach more than 92%, which can protect the solar cell as much as possible without affecting the efficiency of the solar cell. At the same time, the film can bond the photovoltaic glass and the solar cell together, and the presence of the film can seal and insulate the solar cell and prevent water and moisture.

[0084] The back plate can be attached to the film on the back of the solar cell, and the back plate can protect and support the solar cell, has reliable insulation, water resistance and aging resistance, and the back plate can have multiple choices, which can be tempered glass, organic glass, aluminum alloy TPT composite film, etc., which can be set according to the specific circumstances, and is not limited herein. The whole of the back plate, the solar cell, the film and the photovoltaic glass can be arranged on the metal frame, which is the main external supporting structure of the whole back contact battery assembly, and can stably support and install the back contact battery assembly, for example, the back contact battery assembly can be installed at the desired installation position through the metal frame.

[0085] As shown in Figure 5 The utility model further provides a photovoltaic system 100, including the back contact battery assembly 1001 in any one of the above embodiments.

[0086] The photovoltaic system provided by the present application realizes the series connection of the adjacent two parallel structures by arranging the first intermediate bus bar on the cell pieces of the mutually overlapping cell string groups in the adjacent two parallel structures, thereby realizing the hiding of the first intermediate bus bar, and the cell pieces arranged in the second direction are all connected in a shingle manner, so that the whole surface of the assembly presents a complete appearance effect of cell piece splicing, which not only can improve the appearance, but also can greatly reduce the non-cell space of the assembly, further can increase the light receiving area and improve the photoelectric conversion efficiency of the assembly.

[0087] In the present embodiment, the photovoltaic system can be applied in a photovoltaic power station, such as a ground power station, a roof power station, a water surface power station, etc., and can also be applied in a device or apparatus that utilizes solar energy to generate power, such as a user solar power source, a solar street lamp, a solar car, a solar building, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be applied in all fields that need to utilize solar energy to generate power. Taking a photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a combiner box, and an inverter, the photovoltaic array can be an array combination of a plurality of back contact cell assemblies, for example, a plurality of back contact cell assemblies can constitute a plurality of photovoltaic arrays, the photovoltaic arrays are connected to the combiner box, the combiner box can combine the currents generated by the photovoltaic arrays, the combined currents flow through the inverter to be converted into alternating current required by a power grid, and then are connected to a power network to realize solar power supply.

[0088] In the description of the present specification, the description referring to the terms "some embodiments", "exemplary embodiments", "examples", "specific examples", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in one or more embodiments or examples.

[0089] In addition, the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A back contact cell assembly, characterized by, The back contact battery assembly comprises: a plurality of parallel structures arranged along a first direction, each of the parallel structures comprising two battery string groups and a diode arranged along a second direction, the two battery string groups being connected in parallel with the diode; each of the battery string groups comprising two battery strings connected in series and arranged along the first direction, each of the battery strings comprising a plurality of battery pieces connected in series and arranged along the second direction; all the battery pieces arranged along the second direction in the parallel structures being connected in shingled manner; a first intermediate busbar extending along the first direction and connecting in series adjacent first and second parallel structures; the first intermediate busbar being located in a first battery string in the first parallel structure and a second battery string in the second parallel structure, and being located on a battery piece close to one end of a middle line of the parallel structure in the second direction; the first battery string and the second battery string being adjacent battery strings in the first direction.

2. The back contact solar cell assembly of claim 1, wherein, The back contact battery assembly further comprises a second intermediate busbar; the back contact battery assembly having two edges in the first direction; two edge battery strings close to any of the edges being connected by the second intermediate busbar, the second intermediate busbar being located on a battery piece close to one end of a middle line of the parallel structure in the second direction in any of the edge battery strings.

3. The back contact cell assembly of claim 1, wherein, The back contact battery assembly further comprises an end busbar; the end busbar being located on a battery piece away from a middle line of the parallel structure in the second direction and connecting in series two battery strings included in the battery string group.

4. The back contact cell assembly of claim 1, wherein, The back contact battery assembly further comprises a first solder strip and a second solder strip; the first solder strip extending along the second direction and connecting adjacent two battery pieces in the battery string, and the second solder strip extending along the second direction and connecting two battery string groups adjacent in the second direction.

5. The back contact solar cell assembly of claim 1 wherein, The back contact battery assembly comprises a first insulating strip; the first insulating strip extending along the first direction and being arranged between the first intermediate busbar and a back surface of a battery piece corresponding to the first intermediate busbar; the first insulating strip being provided with a first through hole for electrical connection of the first intermediate busbar or a solder strip of a corresponding polarity.

6. The back contact cell assembly of claim 2, wherein, The back contact battery assembly comprises a second insulating strip; the second insulating strip extending along the first direction and being arranged between the second intermediate busbar and a back surface of a battery piece corresponding to the second intermediate busbar; the second insulating strip being provided with a second through hole for electrical connection of the second intermediate busbar and a solder strip of a corresponding polarity.

7. The back contact cell assembly of claim 3, wherein, The back contact battery assembly comprises a third insulating strip; the third insulating strip extending along the first direction and being arranged between the end busbar and a back surface of a battery piece corresponding to the end busbar; the third insulating strip being provided with a third through hole for electrical connection of the end busbar and a solder strip of a corresponding polarity.

8. The back contact solar cell assembly of any of claims 1-7, wherein, A gap width between two battery string groups adjacent in the first direction is 1mm-3mm.

9. Back contact cell assembly according to any of the claims 1-7, characterized in that, An overlapping width of two battery pieces adjacent in the second direction is 0.5mm-1mm.

10. A photovoltaic system characterized by, A battery assembly comprising the battery assembly of any one of claims 1-9.

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