Back contact cell, cell assembly and photovoltaic system

Abstract

The invention provides a back contact battery, a battery assembly and a photovoltaic system. The back contact battery comprises a battery substrate, a plurality of first fine grids and a plurality of second fine grids; the battery substrate comprises a first edge area and a middle area which are sequentially arranged along a first direction; the first fine grids and the second fine grids extend along a second direction, and the second direction is crossed with the first direction; in the middle region, the first fine grids and the second fine grids are alternately arranged along the first direction; in the first edge region, the plurality of first fine grids are sequentially arranged along the first direction; and the second fine grid avoids the first edge region. According to the back contact battery provided by the embodiment of the invention, the second fine grid avoids the first edge region, so that when the back contact battery is applied to the battery assembly, the bus bar can be arranged in the first edge region, the battery assembly does not need to arrange an isolating strip between the bus bar and the back contact battery, and the thickness of the battery assembly can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a back contact battery, a battery assembly and a photovoltaic system. Background Art

[0002] In the related art, when the busbar is set on the back side of the back contact battery, since the grid lines of both polarities in the back contact battery are located on the back side of the battery, it is necessary to set an isolation bar between the busbar and the grid lines of opposite polarity. However, in this way, the thickness of the battery assembly is too thick, which may easily cause the back contact battery to crack and fragment during lamination. Based on this, how to design the back contact battery to reduce the thickness of the battery assembly has become an urgent problem to be solved. Summary of the invention

[0003] The present invention provides a back-contact cell, a cell assembly and a photovoltaic system to solve the technical problem in the related art that the back-contact cell of the cell assembly is prone to hidden cracks and fragments.

[0004] The embodiment of the present invention is implemented as follows: the present invention provides a back-contact cell, a cell string, a cell assembly, and a photovoltaic system. The back-contact cell includes a cell substrate, a plurality of first fine grids, and a plurality of second fine grids, wherein the first fine grids and the second fine grids have opposite polarities; the cell substrate includes a first edge region and a middle region arranged in sequence along a first direction; the first fine grids and the second fine grids both extend in a second direction, and the second direction intersects the first direction; in the middle region, the first fine grids and the second fine grids are alternately arranged along the first direction; in the first edge region, a plurality of the first fine grids are arranged in sequence along the first direction; and the second fine grids avoid the first edge region.

[0005] Furthermore, the battery substrate comprises a first edge, and the first edge extends along the second direction; the first fine grid closest to the first edge is spaced apart from the first edge by 0.2 mm to 2 mm.

[0006] Furthermore, a distance between the second fine grid closest to the first edge and the first edge is 2 mm to 6 mm.

[0007] Furthermore, in the first edge region, a distance between two adjacent first fine gates is smaller than a distance between two adjacent first fine gates in the middle region.

[0008] Furthermore, it also includes a first insulating member and a second insulating member; in the middle area, the first insulating member is located on the side of the first fine grid facing away from the battery substrate, and the second insulating member is located on the side of the second fine grid facing away from the battery substrate; the first insulating member and the second insulating member both avoid the first edge area.

[0009] Furthermore, the back contact battery includes a first main grid and a second main grid, the first main grid and the second main grid both extend along the first direction, the first main grid and the second main grid are alternately arranged along the second direction, the first main grid is connected to the first fine grid, the second main grid is connected to the second fine grid, the first main grid and the second main grid have opposite polarities; the second main grid avoids the first edge area.

[0010] Furthermore, the battery substrate comprises a first edge, and the first edge extends along the second direction; and a distance between an end of the first main grid facing the first edge and the first edge is 0.2 mm to 2 mm.

[0011] Furthermore, a distance between an end of the second main grid facing the first edge and the first edge is 2 mm to 6 mm.

[0012] Furthermore, the battery substrate includes a second edge region, which is located on a side of the middle region away from the first edge region; in the second edge region, a plurality of the second fine grids are arranged in sequence along the first direction; and the first fine grids avoid the second edge region.

[0013] Furthermore, the battery substrate comprises a second edge, and the second edge extends along the second direction; the distance between the second fine grid closest to the second edge and the second edge is 0.2 mm to 2 mm.

[0014] Furthermore, a distance between the first fine grid closest to the second edge and the second edge is 2 mm to 6 mm.

[0015] Furthermore, in the second edge region, a distance between two adjacent second fine grids is smaller than a distance between two adjacent second fine grids in the middle region.

[0016] Furthermore, the back-contact battery also includes a first insulating member and a second insulating member; in the middle area, the first insulating member is located on the side of the first fine grid facing away from the battery substrate, and the second insulating member is located on the side of the second fine grid facing away from the battery substrate; the first insulating member and the second insulating member both avoid the first edge area and the second edge area.

[0017] Furthermore, the back contact battery includes a first main grid and a second main grid, the first main grid and the second main grid both extend along the first direction, the first main grid and the second main grid are alternately arranged along the second direction, the first main grid is connected to the first fine grid, the second main grid is connected to the second fine grid, the first main grid and the second main grid have opposite polarities; the second main grid avoids the first edge area; the first main grid avoids the second edge area.

[0018] An embodiment of the present invention further provides a battery assembly, including a plurality of battery strings, wherein the battery string comprises a plurality of the above-mentioned back-contact batteries.

[0019] Furthermore, the battery string includes a plurality of the back-contact batteries, and two adjacent back-contact batteries are respectively a first battery cell and a second battery cell, and the first battery cell and the second battery cell overlap at a first edge region of the first battery cell.

[0020] Furthermore, the battery string includes a plurality of the back-contact batteries, and the battery assembly also includes a first bus bar; along the first direction, the back-contact battery located at the first end of the battery string is a head battery cell, and the first bus bar is located at a first edge area of ​​the head battery cell.

[0021] Furthermore, the battery assembly also includes a first welding strip and a second welding strip, the first welding strip and the second welding strip both extend along the first direction, the first welding strip and the second welding strip are alternately arranged along the second direction, the first welding strip is conductively connected to the first fine grid of the string head battery cell, and the second welding strip is conductively connected to the second fine grid of the string head battery cell; in the first edge area of ​​the string head battery cell, the first welding strip is arranged along the second direction; and the second welding strip avoids the first edge area of ​​the string head battery cell.

[0022] Furthermore, the battery assembly also includes a second bus bar; along the first direction, the back contact battery located at the second end of the battery string is a string tail battery sheet, and the second bus bar is located at a second edge area of ​​the string tail battery sheet.

[0023] Furthermore, the first welding strip is conductively connected to the first fine grid of the cell at the end of the string, and the second welding strip is conductively connected to the second fine grid of the cell at the end of the string; in the second edge area of ​​the cell at the end of the string, the second welding strip is arranged along the second direction; and the first welding strip avoids the second edge area of ​​the cell at the end of the string.

[0024] An embodiment of the present invention further provides a photovoltaic system, which includes the battery assembly described above.

[0025] In the back contact battery of the embodiment of the present invention, since the second fine grid avoids the first edge area, when the back contact battery is applied to a battery assembly, the bus bar can be arranged in the first edge area, and the battery assembly does not need to provide an isolation bar between the bus bar and the back contact battery, thereby reducing the thickness of the battery assembly and reducing the risk of hidden cracks and fragments of the back contact battery when the battery assembly is laminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the module structure of a photovoltaic system provided by an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of a module structure of a battery assembly provided in one embodiment of the present invention;

[0029] Figure 3 A schematic diagram of a module structure of a battery string provided in one embodiment of the present invention;

[0030] Figure 4 A schematic diagram of a partial structure of a back contact battery provided by an embodiment of the present invention;

[0031] Figure 5 A partial structural schematic diagram of a back contact battery provided by another embodiment of the present invention;

[0032] Figure 6 A partial structural schematic diagram of a back-contact battery provided in yet another embodiment of the present invention, wherein the back-contact battery is provided with a first insulating member and a second insulating member;

[0033] Figure 7 A partial structural schematic diagram of a back-contact battery provided in yet another embodiment of the present invention, wherein the back-contact battery is provided with a first insulating member and a second insulating member;

[0034] Figure 8 A partial structural schematic diagram of a back-contact battery provided in yet another embodiment of the present invention, wherein the back-contact battery is provided with a first insulating member and a second insulating member;

[0035] Fig. 9 A partial structural schematic diagram of a back-contact battery provided in yet another embodiment of the present invention, wherein the back-contact battery is provided with a first insulating member and a second insulating member;

[0036] Fig.10A partial structural schematic diagram of a back contact battery provided in yet another embodiment of the present invention;

[0037] Fig.11 A partial structural schematic diagram of a back contact battery provided in yet another embodiment of the present invention;

[0038] Fig.12 A schematic diagram of a portion of the structure of a battery string in a battery assembly provided in another embodiment of the present invention;

[0039] Fig.13 A schematic diagram of a partial cross-sectional structure of a battery string in a battery assembly provided in yet another embodiment of the present invention;

[0040] Fig.14 A schematic diagram of a portion of the structure of a battery string in a battery assembly provided in yet another embodiment of the present invention;

[0041] Fig.15 for Fig.14 A schematic diagram of a portion of the structure of the battery string;

[0042] Fig.16 for Fig.14 A schematic diagram of another part of the structure of the battery string;

[0043] Fig.17 A schematic structural diagram of a third battery cell in a battery assembly provided in yet another embodiment;

[0044] Fig.18 for Fig.14 Schematic diagram of the soldering strip arrangement structure of the battery string.

[0045] Explanation of the main component symbols: 1000, photovoltaic system; 1100, battery assembly; 1101, battery string; 100, back contact battery; 200, first welding strip; 300, second welding strip; 101, first edge; 102, second edge; 110, first battery cell; 120, second battery cell; 130, third battery cell; 140, first battery cell in the string; 150, last battery cell in the string; 10, battery substrate; 20, first fine grid; 30, second fine grid; 40, first main grid; 50, second main grid; 60, first bus bar; 70, second bus bar; 80, first insulating member; 90, second insulating member; 11, first edge region; 12, middle region; 13, second edge region; 21, first fine grid; 22, last fine grid; 41, first fixed structure; 51, second fixed structure. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0047] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "top", "bottom", "lateral", "longitudinal" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0051] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use scenarios of other materials.

[0052] See also Figures 1 to 3 The photovoltaic system 1000 in the embodiment of the present invention may include the battery assembly 1100 in the embodiment of the present invention, and the battery assembly 1100 in the embodiment of the present invention may include a plurality of battery strings 1101. The battery string 1101 may include the back contact battery 100 in the embodiment of the present invention, and the plurality of back contact batteries 100 in the battery assembly 1100 may be serially connected in sequence through welding strips to form the battery string 1101. The battery strings 1101 in the battery assembly 1100 may be connected in series, in parallel, or in series-parallel combination to realize the bus output of current, for example, the connection between the battery strings 1101 may be realized through a bus bar.

[0053] See also Figures 4 to 11 In an embodiment of the present invention, a back contact battery 100 is provided. The back contact battery 100 comprises a battery substrate 10, a plurality of first fine grids 20 and a plurality of second fine grids 30. The polarities of the first fine grids 20 and the second fine grids 30 are opposite; the battery substrate 10 comprises a first edge region 11 and a middle region 12 arranged in sequence along a first direction; the first fine grids 20 and the second fine grids 30 both extend in a second direction, and the second direction intersects the first direction; in the middle region 12, the first fine grids 20 and the second fine grids 30 are alternately arranged in the first direction; in the first edge region 11, a plurality of first fine grids 20 are arranged in sequence along the first direction, and the second fine grids 30 avoid the first edge region 11.

[0054] Exemplarily, the battery substrate 10 may include a silicon substrate, and may optionally include one or more of a dielectric layer, a doping layer, a passivation layer, etc., which may be specifically configured according to actual conditions.

[0055] In this way, the back contact battery 100 of the embodiment of the present invention, since the second fine grid 30 avoids the first edge area 11, when applied to the battery assembly 1100, the bus bar can be set in the first edge area 11, and the battery assembly 1100 does not need to set an isolation bar between the bus bar and the back contact battery 100, thereby reducing the thickness of the battery assembly 1100 and reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0056] Specifically, the back contact battery 100 includes a battery substrate 10, on which a plurality of first fine grids 20 and second fine grids 30 are arranged at intervals along a first direction, and the first fine grids 20 and the second fine grids 30 both extend along a second direction. The first fine grids 20 and the second fine grids 30 have opposite polarities. For example, the first fine grids 20 are positive and the second fine grids 30 are negative, or the second fine grids 30 are positive and the first fine grids 20 are negative, which is not limited here.

[0057] Meanwhile, the back contact cell 100 may be a back contact cell 100 without a main grid, or may be a back contact cell 100 with a main grid, which is not limited here.

[0058] It is worth noting that in the battery assembly 1100, multiple back contact batteries 100 provided by the embodiments of the present invention may be provided, but not all back contact batteries 100 are provided with bus bars. In the battery assembly 1100, one or more of the back contact batteries 100 may be provided with bus bars, which is not limited here.

[0059] The battery substrate 10 includes a first edge region 11 and a middle region 12. The first edge region 11 and the middle region 12 are arranged in sequence along a first direction. A first fine grid 20 and a second fine grid 30 are arranged in the middle region 12, and the first fine grid 20 and the second fine grid 30 are arranged alternately and at intervals along the first direction.

[0060] In the first edge region 11, the second fine grid 30 is arranged to avoid the first edge region 11, and a plurality of first fine grids 20 are arranged at intervals along a first direction, wherein the first direction intersects with the second direction. Optionally, the first direction and the second direction may be perpendicular to each other.

[0061] It is worth noting that “the second fine gate 30 avoids the first edge region 11 ” means that the second fine gate 30 is not disposed in the first edge region 11 , or in other words, the first edge region 11 is not provided with the second fine gate 30 . All the fine gate lines in the first edge region 11 are the first fine gates 20 .

[0062] Therefore, the first fine grid 20 is arranged in the first edge region 11 and the middle region 12. The second fine grid 30 is arranged in the middle region 12, and is not arranged in the first edge region 11. In this way, since the first edge region 11 has only one fine grid of polarity, the first fine grid 20, when the bus bar is arranged, the bus bar can be arranged in the first edge region 11. It is only necessary to arrange the bus bar and the first fine grid 20 to be electrically connected, and there is no need to arrange the bus bar and the grid line for insulation, so that there is no need to arrange an isolation bar between the back contact battery 100 and the bus bar, so that the thickness of the battery assembly 1100 can be reduced, and the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated is reduced.

[0063] In this embodiment, the cell substrate 10 of the back contact cell 100 includes a plurality of first doping layers and second doping layers (not shown in the figure) arranged alternately, a first fine gate 20 is arranged on the first doping layer, and a second fine gate 30 is arranged on the second doping layer. The first fine gate 20 and the second fine gate 30 both extend along the second direction and are arranged at intervals along the first direction. At the same time, the first doping layer and the second doping layer also extend along the second direction and are arranged along the first direction to form a photocurrent. Among them, the arrangement position of the first doping layer specifically corresponds to the first fine gate 20, and the arrangement position of the second doping layer specifically corresponds to the second fine gate 30. Therefore, in the middle area 12, the first doping layer and the second doping layer are arranged alternately along the first direction; in the first edge area 11, a plurality of first doping layers are arranged, and the number of first doping layers can be multiple, or only one wider first doping layer can be arranged, and the second doping layer avoids the first edge area 11.

[0064] like Figure 4 , Figure 5 , Fig.10 and Fig.11 As shown, in a possible implementation, the battery substrate 10 includes a first edge 101, and the first edge 101 extends along the second direction. The spacing D1 between the first fine grid 20 closest to the first edge 101 and the first edge 101 is 0.2mm to 2mm. For example, it is 0.2mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm. The spacing D2 between the second fine grid 30 closest to the first edge 101 and the first edge 101 is 2mm to 6mm. For example, it is 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm.

[0065] In this way, enough space can be left to form the first edge region 11, and then enough area can be left to place the busbar. Therefore, only one polarity of grid lines can be provided in the area where the busbar is placed, and there is no need to provide an isolation bar between the back contact cell 100 and the busbar. In this embodiment, the back contact cell 100 can be a back contact cell 100 without a main grid or a back contact cell 100 with a main grid, which is not limited here.

[0066] It is worth noting that the first edge 101 is not only the edge of the battery substrate 10, but also the edge of the first edge region 11. Specifically, the first edge 101 is the edge of the first edge region 11 away from the middle region 12.

[0067] like Figure 4 , Figure 5 , Fig.10 and Fig.11 As shown, in a possible implementation, in the first edge region 11, the distance D3 between two adjacent first fine gates 20 is smaller than the distance D4 between two adjacent first fine gates 20 in the middle region 12. In this way, the carrier collection efficiency in the first edge region 11 can be improved.

[0068] Specifically, the spacing D3 between two adjacent first fine grids 20 in the first edge region 11 can be set smaller than the spacing D5 between the adjacent first fine grids 20 and the second fine grids 30 in the middle region, so as to further improve the carrier collection efficiency of the first edge region 11. In the first edge region 11, since only fine grid lines of one polarity are provided, the first fine grids 20 can be arranged more compactly in the first edge region 11, so as to improve the carrier collection efficiency, improve the photoelectric conversion efficiency of the back contact battery 100, and further improve the power generation efficiency of the battery assembly 1100.

[0069] In addition, for the area other than the first edge area 11 and the middle area 12 in the battery substrate 10 of the back contact battery 100, the arrangement of the fine grids can refer to the middle area 12, with the first fine grids 20 and the second fine grids 30 arranged alternately; or, it can be the same as the arrangement of the first edge area 11, with only the first fine grids 20 arranged at intervals and the second fine grids 30 arranged in a avoided manner; or, it can be the opposite of the arrangement of the first edge area 11, with only the second fine grids 30 arranged at intervals and the first fine grids 20 arranged in a avoided manner. This is not limited here.

[0070] like Figures 6 to 9 As shown, in a possible implementation, the back contact battery 100 further includes a first insulating member 81 and a second insulating member 82; in the middle region 12, the first insulating member 81 is located on the side of the first fine grid 20 facing away from the battery substrate 10, and the second insulating member 82 is located on the side of the second fine grid 30 facing away from the battery substrate 10; the first insulating member 81 and the second insulating member 82 both avoid the first edge region 11. Alternatively, the grid lines can be interrupted in the corresponding regions to avoid short circuits between the welding strips and the grid lines.

[0071] In this way, in the back contact battery 100 in the embodiment of the present invention, an insulating member may be provided only in the middle area 12, and the first insulating member 81 and the second insulating member 82 both avoid the first edge area 11. Therefore, when the back contact battery 100 is applied to the battery assembly 1100, the thickness of the battery assembly 1100 can be reduced, further reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0072] It is understandable that if Figure 6As shown, in the battery assembly 1100, when a bus bar is provided in the first edge region 11 of the back contact battery 100 in the embodiment of the present invention, when the back contact battery 100 is connected with a welding strip, there is no need to additionally provide an insulating member in the first edge region 11, thereby further reducing the thickness of the battery assembly 1100.

[0073] Specifically, the first insulating member 81 and the second insulating member 82 are insulating structures of the back contact battery 100, and are arranged on the side of the gate line facing away from the battery substrate 10 to isolate the gate lines of different polarities and prevent the back contact battery 100 from having a short circuit. The first insulating member 81 and the second insulating member 82 can be prepared by laying or coating. In one embodiment, the first insulating member 81 and the second insulating member 82 can be insulating glue layers arranged on the corresponding gate lines by a spraying process.

[0074] like Figure 8 As shown, in a possible implementation, in the first edge region 11 , the first insulating member 81 is located on the side of the first fine grid 20 facing away from the battery substrate 10 . The second insulating member 82 avoids the first edge region 11 .

[0075] It is understandable that in the battery assembly 1100, when the first edge region 11 of the busbar-free back-contact battery 100 is not provided with a busbar, when the back-contact battery 100 is connected with a welding strip, a second insulating member 82 may be provided at the second fine grid 30 in the middle region 12, and a first insulating member 81 may be provided at the first fine grid 20 in the middle region 12 and the first edge region 11, so as to prevent the back-contact battery 100 from short-circuiting. At the same time, because there is only one polarity of the grid line in the first edge region 11, the second insulating member 82 does not need to be provided in the first edge region 11.

[0076] Specifically, the arrangement and setting manner of the first insulating members 81 in the first edge region 11 may refer to the arrangement and setting manner of the first insulating members 81 in the middle region 12 .

[0077] In a possible implementation, Figure 5 , Figure 7 , Fig. 9 and Fig.11As shown, the back contact cell 100 further includes a first main grid 40 and a second main grid 50, both of which extend along the first direction, and are alternately arranged along the second direction, the first main grid 40 is connected to the first fine grid 20, and the second main grid 50 is connected to the second fine grid 30, and the first main grid 40 and the second main grid 50 have opposite polarities; in the middle area 12, the first main grid 40 and the second main grid 50 are alternately arranged along the second direction; in the first edge area 11, a plurality of first main grids 40 are sequentially arranged along the second direction; and the second main grid 50 avoids the first edge area 11. The first main grid 40 and the first fine grid 20 have the same polarity, and the second main grid 50 and the second fine grid 30 have the same polarity.

[0078] In this way, the back contact battery 100 of the embodiment of the present invention, since the second main grid 50 avoids the first edge area 11, when applied to the battery assembly 1100, a bus bar can be set in the first edge area 11, and then the battery assembly 1100 does not need to set an isolation bar between the bus bar and the back contact battery 100, thereby reducing the thickness of the battery assembly 1100 and reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0079] Specifically, the back contact battery 100 can be a back contact battery 100 with a main grid. The extension direction of the main grid intersects with the extension direction of the fine grid. The first main grid 40 is conductively connected to the first fine grid 20, and the second main grid 50 is conductively connected to the second fine grid 30. The polarities of the first main grid 40 and the second main grid 50 are opposite. For example, the first main grid 40 is positive and the second main grid 50 is negative, or the second main grid 50 is positive and the first main grid 40 is negative, which is not limited here.

[0080] It is worth noting that "the second main grid 50 avoids the first edge region 11" means that the second main grid 50 is not arranged in the first edge region 11, or in other words, the first edge region 11 is not provided with the second main grid 50. All the main grid lines in the first edge region 11 are the second main grid 50. Therefore, in the first edge region 11, only grid lines of one polarity, the first main grid 40 and the first fine grid 20 are provided. Therefore, when the busbar is arranged in the first edge region 11, the grid lines in the first edge region 11 do not need to be insulated from the busbar, and further, there is no need to arrange isolation bars, so that the thickness of the battery assembly 1100 can be further reduced, and the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated can be reduced.

[0081] In addition, for the area other than the first edge area 11 and the middle area 12 in the cell substrate 10 of the back contact cell 100 with a busbar, the arrangement of the busbar and the fine grid can refer to the middle area 12, with the first busbar 40 and the second busbar 50 arranged alternately, and the first fine grid 20 and the second fine grid 30 arranged alternately; or, it can also be the same as the arrangement of the first edge area 11, with only the first busbar 40 and the first fine grid 20 arranged alternately, and the second busbar 50 and the second fine grid 30 are arranged in a circumventing manner; or, it can also be the opposite of the arrangement of the first edge area 11, with only the second busbar 50 and the second fine grid 30 arranged alternately, and the first busbar 40 and the second fine grid 30 are arranged in a circumventing manner. No limitation is made here.

[0082] like Figure 5 and Fig.11 As shown, in a possible implementation, the battery substrate 10 includes a first edge 101, and the first edge 101 extends along the second direction; the distance D6 between the end of the first main grid 40 facing the first edge 101 and the first edge 101 is 0.2mm to 2mm. For example, 0.2mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.5mm, 1.6mm, 1.8mm, 2mm.

[0083] Furthermore, the spacing D7 between one end of the second main grid 50 facing the first edge 101 and the first edge 101 is 2 mm to 6 mm. For example, it is 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 5.5 mm, and 6 mm. In this way, for the back contact battery 100 with a main grid, enough space can be left to form the first edge area 11. In addition, there is enough area to place the bus bar, so that there is only one polarity of the grid line in the area where the bus bar is placed, and there is no need to set an isolation strip between the back contact battery 100 and the bus bar, thereby reducing the thickness of the battery assembly 1100 and further reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0084] Specifically, the distance D6 between the end of the first main grid 40 facing the first edge 101 and the first edge 101 can be set to be smaller than the distance D7 between the end of the second main grid 50 facing the first edge 101 and the first edge 101. Thus, a grid line arrangement structure in which the first main grid 40 and the second main grid 50 are staggered is formed. In this way, a grid line region with only one polarity can be formed on the battery substrate 10.

[0085] Furthermore, if Figure 7As shown, in such an embodiment, for the back contact battery 100 with a main grid, in the middle area 12, the first insulating member 81 is located on the side of the first fine grid 20 facing away from the battery substrate 10, and the second insulating member 82 is also located on the side of the second fine grid 30 facing away from the battery substrate 10; the first insulating member 81 and the second insulating member 82 both avoid the first edge area 11. Alternatively, the grid line can be interrupted in the corresponding area to avoid short circuit between the welding strip and the grid line.

[0086] It is understandable that in the battery assembly 1100, when a bus bar is provided in the first edge region 11 of the back-contact battery 100 with a main grid, when the back-contact battery 100 is connected with a welding strip, there is no need to additionally provide an insulating member in the first edge region 11, which can further reduce the thickness of the battery assembly.

[0087] It is understandable that in the battery assembly 1100, when the first edge region 11 of the back contact battery 100 with a main grid is not provided with a bus bar, when the back contact battery 100 is connected with a welding strip, a second insulating member 82 may be provided at the second fine grid 30 in the middle region 12, and a first insulating member 81 may be provided at the first fine grid 20 in the middle region 12 and the first edge region 11, so as to prevent the back contact battery 100 from short-circuiting. At the same time, because there is only one polarity grid line in the first edge region 11, the second insulating member 82 does not need to be provided in the first edge region 11.

[0088] Specifically, the arrangement and setting manner of the first insulating members 81 in the first edge region 11 may refer to the arrangement and setting manner of the first insulating members 81 in the middle region 12 .

[0089] In a possible implementation, Figures 4 to 11 As shown, the battery substrate 10 also includes a second edge region 13, which is located on the side of the middle region 12 away from the first edge region 11; in the second edge region 13, a plurality of second fine grids 30 are arranged in sequence along the first direction; and the first fine grids 20 avoid the second edge region 13.

[0090] In this way, the back contact cell 100 of the embodiment of the present invention, since the first fine grid 20 avoids the second edge area 13, when the back contact cell 100 is applied to the battery assembly 1100, a bus bar can also be set in the second edge area 13, and then the battery assembly 1100 does not need to set an isolation bar between the bus bar and the back contact cell 100, thereby reducing the thickness of the battery assembly 1100 and further reducing the risk of hidden cracks and fragments of the back contact cell 100 when the battery assembly 1100 is laminated.

[0091] Specifically, the second edge region 13 and the first edge region 11 are arranged opposite to each other, and the second edge region 13 and the first edge region 11 are respectively located on both sides of the middle region 12. In the second edge region 13, the first fine gate 20 is arranged to avoid the second edge region 13, and a plurality of second fine gates 30 are arranged at intervals along the first direction. Correspondingly, in the second edge region 13, a plurality of second doped layers are arranged in sequence along the first direction, the first doped layers avoid the second edge region 13, or only a second doped layer with a larger width in the first direction is arranged in the second edge region 13.

[0092] It is worth noting that "the first fine grid 20 avoids the second edge region 13" means that the first fine grid 20 is not arranged in the second edge region 13, or in other words, the second edge region 13 is not provided with the first fine grid 20. All the fine grid lines in the first edge region 11 are the second fine grids 30. Therefore, since the second edge region 13 has only one polarity of fine grids, the second fine grid 30, when setting the bus bar, the bus bar can be set in the second edge region 13. It is only necessary to set the bus bar and the second fine grid 30 to be electrically connected, and there is no need to set the bus bar and the grid line insulation, so there is no need to set the isolation bar, so that the thickness of the battery assembly 1100 can be reduced, and the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated is reduced.

[0093] It is understandable that when the back-contact battery 100 is applied to the battery assembly 1100 , a bus bar may be provided in the first edge region 11 and / or the second edge region 13 of the back-contact battery 100 , which is not limited here.

[0094] In a possible implementation, Fig.10 and Fig.11 As shown, in a possible implementation, the battery substrate 10 includes a second edge 102, and the second edge 102 extends along the second direction; the distance D8 between the second fine grid 30 closest to the second edge 102 and the second edge 102 is 0.2mm to 2mm. For example, it is 0.2mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm. The distance D9 between the first fine grid 20 closest to the second edge 102 and the second edge 102 is 2mm to 6mm. For example, it is 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm.

[0095] In this way, there is enough space to form the second edge region 13, and thus enough area to place the busbar, so only grid lines of one polarity can be arranged in the area where the busbar is placed, without the need to arrange isolation bars between the back contact battery 100 and the busbar.

[0096] It is worth noting that the second edge 102 is not only the edge of the battery substrate 10, but also the edge of the second edge region 13. Specifically, the second edge 102 is the edge of the second edge region 13 away from the middle region 12. The second edge 102 is arranged opposite to the first edge 101, and is respectively arranged on both sides of the back contact battery 100 along the first direction.

[0097] like Fig.10 and Fig.11 As shown, in a possible implementation, in the second edge region 13, the interval D10 between two adjacent second fine gates 30 is smaller than the interval D13 between two adjacent second fine gates 30 in the middle region 12. In this way, the carrier collection efficiency in the second edge region 13 can be improved.

[0098] Specifically, the spacing D10 between two adjacent second fine grids 30 in the second edge region 13 can be set smaller than the spacing D5 between the adjacent first fine grids 20 and the second fine grids 30 in the middle region 12, so as to improve the carrier collection efficiency of the second edge region 13. In the second edge region 13, since only fine grid lines of one polarity are provided, the second fine grids 30 can be arranged more compactly in the second edge region 13, so as to improve the carrier collection efficiency, improve the photoelectric conversion efficiency of the back contact battery 100, and further improve the power generation efficiency of the battery assembly 1100.

[0099] like Figure 6 As shown, in a possible implementation, the busbar-free back contact cell 100 further includes a first insulating member 81 and a second insulating member 82; in the middle region 12, the first insulating member 81 is located on the side of the first fine grid 20 facing away from the cell substrate 10, and the second insulating member 82 is located on the side of the second fine grid 30 facing away from the cell substrate 10; the first insulating member 81 avoids the first edge region 11 and the second edge region 13; the second insulating member 82 avoids the first edge region 11 and the second edge region 13. Alternatively, the grid line can be interrupted in the corresponding region to avoid short circuit between the welding strip and the grid line.

[0100] It can be understood that in the battery assembly 1100, when the first edge area 11 and the second edge area 13 of the back contact battery 100 in the embodiment of the present invention are provided with bus bars, when the back contact battery 100 is connected with the welding ribbon, there is no need to additionally provide insulating parts in the first edge area 11 and the second edge area 13, thereby further reducing the thickness of the battery assembly 1100.

[0101] Therefore, in the back contact battery 100 in the embodiment of the present invention, an insulating member may be provided only in the middle area 12, and the first insulating member 81 and the second insulating member 82 both avoid the first edge area 11 and the second edge area 13 on both sides of the middle area 12. Therefore, when applied to the battery assembly 1100, the thickness of the battery assembly 1100 can be reduced, and the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated can be further reduced.

[0102] like Figure 8 As shown, in a possible implementation, in the second edge region 13 of the busbar-less back contact cell 100 , the first insulating member 81 is located on the side of the first fine grid 20 facing away from the cell substrate 10 . The first insulating member 81 avoids the second edge region 13 .

[0103] It is understandable that in the battery assembly 1100, when the second edge region 13 of the back contact battery 100 in the embodiment of the present invention is not provided with a bus bar, when the back contact battery 100 is connected with a welding ribbon, a second insulating member 82 may be provided on the second fine grids 30 in the middle region 12 and the second edge region 13 to prevent the back contact battery 100 from short-circuiting. At the same time, because there is only one polarity fine grid in the second edge region 13, it is not necessary to provide the first insulating member 81 in the second edge region 13.

[0104] It is understandable that in the battery assembly 1100, when the first edge region 11 and the second edge region 13 of the back contact battery 100 in the embodiment of the present invention are not provided with a bus bar, when the back contact battery 100 is connected with a welding strip, a first insulating member 81 may be provided on the first fine grid 20 in the middle region 12 and the first edge region 11, and a second insulating member 82 may be provided on the second fine grid 30 in the middle region 12 and the second edge region 13 to prevent the back contact battery 100 from short-circuiting. At the same time, because there is only one polarity fine grid in the first edge region 11, it is not necessary to provide the second insulating member 82 in the first edge region 11; and because there is only one polarity fine grid in the second edge region 13, it is not necessary to provide the first insulating member 81 in the second edge region 13.

[0105] Specifically, the arrangement and arrangement of the first insulating member 81 in the first edge region 11 can refer to the arrangement and arrangement of the first insulating member 81 in the middle region 12. Meanwhile, the arrangement and arrangement of the second insulating member 82 in the second edge region 13 can refer to the arrangement and arrangement of the second insulating member 82 in the middle region 12.

[0106] It is understandable that for the busbar-free back contact cell 100, a busbar may be provided in the first edge region 11 and / or the second edge region 13, which is not limited here. Correspondingly, an insulating member may also be provided in the first edge region 11 and / or the second edge region 13, or an insulating member may not be provided in both the first edge region 11 and the second edge region 13, which is not limited here.

[0107] like Figure 5 , Figure 7 , Fig. 9 and Fig.11 As shown, in a possible embodiment, the back contact battery 100 includes a first main grid 40 and a second main grid 50, both of which extend along the first direction, the first main grid 40 is connected to the first fine grid 20, and the second main grid 50 is connected to the second fine grid 30; in the middle area 12, the first main grid 40 and the second main grid 50 are alternately arranged along the second direction; in the first edge area 11, a plurality of first main grids 40 are arranged in sequence along the second direction, and the first main grid 40 and the second main grid 50 are alternately arranged along the second direction; the second main grid 50 avoids the first edge area 11; the first main grid 40 avoids the second edge area 13.

[0108] In this way, the back contact battery 100 of the embodiment of the present invention, since the second main grid 50 avoids the second edge area 13, and the first main grid 40 avoids the second edge area 13, when the back contact battery 100 is applied to the battery assembly 1100, a bus bar can be set in the first edge area 11 and / or the second edge area 13, and then the battery assembly 1100 does not need to set an isolation bar between the bus bar and the back contact battery 100, thereby reducing the thickness of the battery assembly 1100 and reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0109] It is worth noting that "the first main grid 40 avoids the second edge region 13" means that the first main grid 40 is not arranged in the second edge region 13, or in other words, the second edge region 13 is not provided with the first main grid 40. All the main grid lines in the second edge region 13 are the first main grid 40. Therefore, in the second edge region 13, only grid lines of one polarity, the second main grid 50 and the second fine grid 30 are provided. Therefore, when the busbar is arranged in the second edge region 13, the grid lines in the second edge region 13 do not need to be insulated from the busbar, and further, there is no need to arrange isolation bars, so that the thickness of the battery assembly 1100 can be further reduced, and the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated is reduced.

[0110] like Figure 7As shown, in a possible implementation, the back contact battery 100 with a main grid further includes a first insulating member 81 and a second insulating member 82; in the middle region 12, the first insulating member 81 is located on the side of the first fine grid 20 facing away from the battery substrate 10, and the second insulating member 82 is located on the side of the second fine grid 30 facing away from the battery substrate 10; the first insulating member 81 avoids the first edge region 11 and the second edge region 13; the second insulating member 82 avoids the first edge region 11 and the second edge region 13. Alternatively, the grid line can be interrupted in the corresponding region to avoid short circuit between the welding strip and the grid line.

[0111] It can be understood that in the battery assembly 1100, when the first edge area 11 and the second edge area 13 of the back contact battery 100 in the embodiment of the present invention are provided with bus bars, when the back contact battery 100 is connected with the welding ribbon, there is no need to additionally provide insulating parts in the first edge area 11 and the second edge area 13, thereby further reducing the thickness of the battery assembly 1100.

[0112] Therefore, in the back contact battery 100 in the embodiment of the present invention, an insulating member may be provided only in the middle area 12, and the first insulating member 81 and the second insulating member 82 both avoid the first edge area 11 and the second edge area 13 on both sides of the middle area 12. Therefore, when applied to the battery assembly 1100, the thickness of the battery assembly 1100 can be reduced, and the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated can be further reduced.

[0113] like Fig. 9 As shown, in a possible implementation, in the second edge region 13 of the back contact battery 100 with a main grid, the second insulating member 82 is located on the side of the first fine grid 20 facing away from the battery substrate 10. The first insulating member 81 avoids the second edge region 13. Alternatively, the grid line can be interrupted in the corresponding area to avoid a short circuit between the welding strip and the grid line.

[0114] It is understandable that in the battery assembly 1100, when the second edge region 13 of the back contact battery 100 in the embodiment of the present invention is not provided with a bus bar, when the back contact battery 100 is connected with a welding ribbon, a second insulating member 82 may be provided on the second fine grid 30 of the second edge region 13 to prevent the back contact battery 100 from short-circuiting. At the same time, because there is only one grid line of polarity in the second edge region 13, it is not necessary to provide the first insulating member 81 in the second edge region 13.

[0115] It is understandable that in the battery assembly 1100, when the first edge region 11 and the second edge region 13 of the back contact battery 100 in the embodiment of the present invention are not provided with a bus bar, when the back contact battery 100 is connected with a welding strip, a first insulating member 81 may be provided in the first fine grid 20 in the middle region 12 and the first edge region 11, and a second insulating member 82 may be provided in the second fine grid 30 in the middle region 12 and the second edge region 13 to prevent the back contact battery 100 from short-circuiting. At the same time, because there is only one polarity of the grid line in the first edge region 11, it is not necessary to provide the second insulating member 82 in the first edge region 11; and because there is only one polarity of the grid line in the second edge region 13, it is not necessary to provide the first insulating member 81 in the second edge region 13.

[0116] Specifically, the arrangement and arrangement of the first insulating member 81 in the first edge region 11 can refer to the arrangement and arrangement of the first insulating member 81 in the middle region 12. Meanwhile, the arrangement and arrangement of the second insulating member 82 in the second edge region 13 can refer to the arrangement and arrangement of the second insulating member 82 in the middle region 12.

[0117] It is understandable that for the back contact battery 100 with a main grid, a bus bar may be provided in the first edge region 11 and / or the second edge region 13, which is not limited here. Correspondingly, an insulating member may also be provided in the first edge region 11 and / or the second edge region 13, or an insulating member may not be provided in both the first edge region 11 and the second edge region 13, which is not limited here.

[0118] like Figure 5 , as shown, in a possible implementation, the first main grid 40 includes a first fixed structure 41, and the second main grid 50 includes a second fixed structure 51. The first fixed structure 41 is used to set solder paste or insulating glue, and the first main grid 40 is connected to the corresponding solder strip through the first fixed structure 41. The second fixed structure 51 is used to set solder paste or insulating glue, and the second main grid 50 is connected to the corresponding solder strip through the second fixed structure 51. The first fixed structure 41 and the second fixed structure 51 can be PAD points or welding points. In addition, for the main grid-free back contact battery 100, a fixed structure (not shown) can be set on the first fine grid 20 and the second fine grid 30 to connect the solder strip.

[0119] Please refer to Figures 12 to 18 Furthermore, for the battery assembly 1100 in the embodiment of the present invention, the battery assembly 1100 includes a plurality of battery strings 1101, and the battery string 1101 may include a plurality of back-contact batteries 100 in any one of the above-mentioned embodiments.

[0120] like Fig.13As shown, in a possible implementation, a battery string 1101 includes a plurality of back contact batteries 100. Two adjacent back contact batteries 100 are a first battery cell 110 and a second battery cell 120, respectively. The first battery cell 110 and the second battery cell 120 overlap at a first edge region 11 of the first battery cell 110.

[0121] In this way, for the overlapping first battery cell 110 and the second battery cell 120, because the first battery cell 110 and the second battery cell 120 overlap in the first edge region 11 of the first battery cell 110, and the grid lines in the first edge region 11 do not need to be insulated by an insulating member, there is no need to set an insulating member in the overlapping portion of two adjacent battery cells, thereby reducing the thickness of the overlapping portion of the first battery cell 110 and the second battery cell 120, thereby reducing the thickness of the battery assembly 1100, and further reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0122] Furthermore, because the first battery cell 110 and the second battery cell 120 overlap at the first edge region 11 of the first battery cell 110, and the first edge region 11 of the first battery cell 110 does not need to be provided with an insulating member, the thickness of the overlapping portion of the first battery cell 110 and the second battery cell 120 can be reduced, thereby reducing the thickness of the battery assembly 1100, and further reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0123] In a possible implementation, Fig.14 As shown, the battery string 1101 includes a plurality of back-contact batteries 100 and a first bus bar 60. Along the first direction, the back-contact battery 100 at the first end of the battery string 1101 is the first battery cell 140 of the string, and the first bus bar 60 is located at the first edge region 11 of the first battery cell 140.

[0124] Specifically, the first bus bar 60 is located in the first edge region 11 of the string head cell 140. In this way, in the back contact cell 100 of the embodiment of the present invention, since the first bus bar 60 is provided in the first edge region 11 of the grid line with only one polarity, there is no need to provide an isolation bar between the back contact cell 100 and the first bus bar 60, thereby reducing the thickness of the battery assembly 1100 and further reducing the risk of hidden cracks and fragments of the back contact cell 100 when the battery assembly 1100 is laminated.

[0125] like Figures 14 to 18As shown, for the arrangement of the busbars, the first busbar 60 may cover or not cover the first fine grid 20 in the first edge region 11. In a possible implementation, the first busbar 60 covers the first fine grid 20 closest to the first busbar 60. For example, the first cell 140 in the string includes a first fine grid 21, which is the first first fine grid 20 of the first cell 140 in the first direction, and the first fine grid 21 is the first fine grid 20 closest to the first busbar 60. The first busbar 60 is arranged on the side of the first fine grid 21 away from the battery substrate 10, and the first busbar 60 covers the first fine grid 21. In this way, the current loss of the first busbar 60 when collecting current can be reduced, and the battery efficiency of the battery assembly 1100 can be improved.

[0126] In this embodiment, the first cell 140 of the string can be a back contact cell 100 with a main grid or a back contact cell 100 without a main grid, which is not limited here. In addition, the first bus bar 60 can be arranged to be spaced apart from each of the first fine grid 20 and the second fine grid 30 .

[0127] Of course, in other embodiments, a gap may be provided between the first bus bar 60 and the first fine grid 21. In other words, the first bus bar 60 may not cover the first fine grid 21, which is not limited here.

[0128] Moreover, when the battery cell 140 in the string is a back contact battery 100 with a main grid, the first bus bar 60 can be arranged on the side of the first main grid 40 of the battery cell 140 in the string away from the battery substrate 10. At the same time, the first bus bar 60 and the second main grid 50 of the battery cell 140 in the string are both arranged at intervals. Specifically, at the same time, the interval D11 between the first bus bar 60 and the second main grid 50 of the battery cell 140 in the string is 1 mm to 5 mm. For example, it is 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm.

[0129] like Fig.18 As shown, in a possible embodiment, the battery assembly 1100 also includes a first welding strip 200 and a second welding strip 300, both of which extend along the first direction, and the first welding strip 200 and the second welding strip 300 are alternately arranged along the second direction, the first welding strip 200 is conductively connected to the first fine grid 20, and the second welding strip 300 is conductively connected to the second fine grid 30; the second welding strip 300 avoids the first edge area 11 of the string head battery cell 140.

[0130] In this way, in the first edge area 11 of the string head battery cell 140, there is only a welding strip with one polarity. When setting the first bus bar 60, it is only necessary to connect the first bus bar 60 with the first welding strip 200. There is no need to insulate the first bus bar 60 from the second welding strip 300, and there is no need to set an isolation strip between the bus bar and the welding strip. This can reduce the thickness of the battery assembly 1100 and further reduce the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0131] It is worth noting that “the second welding strip 300 avoids the first edge region 11 of the string battery cell 140” means that the second welding strip 300 is not provided in the first edge region 11 of the string battery cell 140, or in other words, the first edge region 11 of the string battery cell 140 is not provided with the second welding strip 300. The first edge region 11 of the string battery cell 140 is entirely the first welding strip 200.

[0132] Specifically, for a back-contact cell 100 with a main grid, the first welding strip 200 is specifically connected to the connection structure of the first main grid 40, and the second welding strip 300 is specifically connected to the connection structure of the second main grid 50. For a back-contact cell 100 without a main grid, the first welding strip 200 is specifically connected to the connection structure of the first fine grid 20, and the second welding strip 300 is specifically connected to the connection structure of the second fine grid 30.

[0133] When the first bus bar 60 is specifically provided, the first bus bar 60 can be provided in the first edge region 11 of the string battery cell 140, and along the second direction, the first welding strips 200 are arranged at intervals in the first edge region 11 of the string battery cell 140. In addition, the first edge region 11 of the string battery cell 140 is not provided with the second welding strip 300. Therefore, in the first edge region 11 where the first bus bar 60 is provided, there is only a welding strip of one polarity, so there is no need to insulate between the bus bar and the welding strip, thereby reducing the thickness of the battery assembly 1100.

[0134] like Figures 14 to 18 As shown, in a possible implementation, the battery string 1101 further includes a second bus bar 70. The back contact battery 100 at the end of the battery string 1101 is a battery cell 150 at the end of the string, and the second bus bar 70 is located at the second edge region 13 of the battery cell 150 at the end of the string.

[0135] Specifically, the second bus bar 70 is located in the second edge region 13 of the string tail cell 150. In this way, in the back contact cell 100 of the embodiment of the present invention, since the second bus bar 70 is provided in the second edge region 13 of the grid line with only one polarity, there is no need to provide a spacer bar between the back contact cell 100 and the second bus bar 70, thereby reducing the thickness of the battery assembly 1100 and further reducing the risk of hidden cracks and fragments of the back contact cell 100 when the battery assembly 1100 is laminated.

[0136] It is worth noting that the first end of the battery string 1101 refers to the first end of the battery string 1101 arranged along the first direction. The second end of the battery string 1101 refers to the second end of the battery string 1101 arranged along the first direction.

[0137] like Fig.18 As shown, in a possible implementation, the first welding strip 200 avoids the second edge region 13 of the end-of-string battery cell 150. In this way, in the second edge region 13 of the end-of-string battery cell 150, there is only a welding strip of one polarity. When the second bus bar 70 is set, it is only necessary to set the second bus bar 70 to be connected with the second welding strip 300, and there is no need to set the second bus bar 70 to be insulated from the first welding strip 200, and there is no need to set an isolation strip between the bus bar and the welding strip, so that the thickness of the battery assembly 1100 can be reduced, and the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated is further reduced.

[0138] It is worth noting that “the first welding ribbon 200 avoids the second edge region 13 of the end cell 150” means that the first welding ribbon 200 is not disposed in the second edge region 13 of the end cell 150, or in other words, the second edge region 13 of the end cell 150 is not provided with the first welding ribbon 200. The second edge region 13 of the end cell 150 is entirely provided with the second welding ribbon 300.

[0139] When the second bus bar 70 is specifically provided, the second bus bar 70 can be provided in the second edge region 13 of the end cell 150, and along the second direction, the second welding strips 300 are arranged at intervals in the second edge region 13 of the end cell 150. In addition, the second edge region 13 of the end cell 150 is not provided with the first welding strip 200. Therefore, in the second edge region 13 where the second bus bar 70 is provided, there is only one polarity welding strip, so there is no need to insulate between the bus bar and the welding strip, thereby reducing the thickness of the battery assembly 1100.

[0140] like Figures 14 to 18As shown, for the arrangement of the busbar, the second busbar 70 may cover or not cover the second fine grid 30 in the second edge region 13. In a possible implementation, the second busbar 70 covers the second fine grid 30 closest to the second busbar 70. For example, the last cell 150 in the string includes the last fine grid 22, which is the last second fine grid 30 of the first cell 140 in the first direction, and the last fine grid 22 is the second fine grid 30 closest to the second busbar 70. The second busbar 70 is arranged on the side of the last fine grid 22 away from the battery substrate 10, and the second busbar 70 covers the last fine grid 22. In this way, the current loss of the second busbar 70 when collecting current can be reduced, and the battery efficiency of the battery assembly 1100 can be improved.

[0141] In this embodiment, the end cell 150 can be a back contact cell 100 with a main grid or a back contact cell 100 without a main grid, which is not limited here. In addition, the second bus bar 70 can be arranged to be spaced apart from each of the first fine grid 20 and the second fine grid 30 .

[0142] Of course, in other embodiments, a gap may be provided between the second bus bar 70 and the last fine grid 22. In other words, the second bus bar 70 may not cover the last fine grid 22, which is not limited here.

[0143] Moreover, when the end cell 150 of the string is a back contact cell 100 with a main grid, the second bus bar 70 can be arranged on the side of the second main grid 50 of the end cell 150 away from the cell substrate 10. At the same time, the second bus bar 70 and the first main grid 40 of the end cell 150 are arranged at intervals. Specifically, the interval D12 between the second bus bar 70 and the first main grid 40 of the end cell 150 is 1 mm to 5 mm. For example, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm.

[0144] like Fig.17 As shown, in a possible implementation, the battery string 1101 further includes a third battery cell 130. The first bus bar 60 is located at the first edge region 11 of the third battery cell 130, and the second bus bar 70 is located at the second edge region 13 of the third battery cell 130. That is, the battery assembly 1100 may include a back contact battery 100 having both the first bus bar 60 and the second bus bar 70. In this way, there is no need to set an isolation bar for insulation between the third battery cell 130 and the first bus bar 60 and between the third battery cell 130 and the second bus bar 70, thereby reducing the thickness of the battery assembly 1100 and further reducing the risk of hidden cracks and fragments of the back contact battery 100 when the battery assembly 1100 is laminated.

[0145] It is understandable that in such an embodiment, the battery assembly 1100 may also include a frame, a back plate, photovoltaic glass and an adhesive film. The adhesive film may be filled between the front and back of the battery cell and the photovoltaic glass, adjacent battery cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film may be an EVA adhesive film or a POE adhesive film. The specific selection may be based on actual conditions and is not limited here.

[0146] Photovoltaic glass can cover the adhesive film on the front of the cell. Photovoltaic glass can be ultra-white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of ultra-white glass can reach more than 92%, which can protect the cell without affecting the efficiency of the cell as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the cell together. The presence of the adhesive film can seal and insulate the cell and make it waterproof and moisture-proof.

[0147] The backplane can be attached to the film on the back of the battery cell. The backplane can protect and support the battery cell and has reliable insulation, water resistance and aging resistance. There are multiple options for the backplane, which can usually be tempered glass, organic glass, aluminum alloy TPT composite film, etc. It can be set according to the specific situation and is not limited here. The whole composed of the backplane, battery cell, film and photovoltaic glass can be set on the frame. The frame serves as the main external support structure of the entire battery assembly 1100 and can provide stable support and installation for the battery assembly 1100. For example, the battery assembly 1100 can be installed at the required location through the frame.

[0148] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0149] In addition, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A back contact battery, characterized in that: The invention comprises a battery substrate, a plurality of first fine grids and a plurality of second fine grids, wherein the first fine grids and the second fine grids have opposite polarities; the battery substrate comprises a first edge region and a middle region arranged in sequence along a first direction; the first fine grids and the second fine grids both extend along a second direction, and the second direction intersects the first direction; In the middle region, the first fine grids and the second fine grids are alternately arranged along the first direction; In the first edge region, a plurality of the first fine grids are sequentially arranged along the first direction; and the second fine grids avoid the first edge region.

2. The back contact cell according to claim 1, characterized in that: The battery substrate comprises a first edge, and the first edge extends along the second direction; The distance between the first fine grid closest to the first edge and the first edge is 0.2 mm to 2 mm.

3. The back contact battery according to claim 2, characterized in that: The distance between the second fine grid closest to the first edge and the first edge is 2 mm to 6 mm.

4. The back contact cell according to claim 1, characterized in that: In the first edge region, a distance between two adjacent first fine grids is smaller than a distance between two adjacent first fine grids in the middle region.

5. The back contact cell according to claim 1, characterized in that: The back contact cell further includes a first insulating member and a second insulating member; In the middle area, the first insulating member is located on a side of the first fine grid facing away from the battery substrate, and the second insulating member is located on a side of the second fine grid facing away from the battery substrate; The first insulating member and the second insulating member both avoid the first edge area.

6. The back contact cell according to claim 1, characterized in that: The back contact battery comprises a first main grid and a second main grid, the first main grid and the second main grid both extend along the first direction, the first main grid and the second main grid are alternately arranged along the second direction, the first main grid is connected to the first thin grid, the second main grid is connected to the second thin grid, and the first main grid and the second main grid have opposite polarities; The second main grid avoids the first edge area.

7. The back contact cell according to claim 6, characterized in that: The battery substrate comprises a first edge, and the first edge extends along the second direction; a distance between an end of the first main grid facing the first edge and the first edge is 0.2 mm to 2 mm.

8. The back contact battery according to claim 7, characterized in that: A distance between one end of the second main grid facing the first edge and the first edge is 2 mm to 6 mm.

9. The back contact cell according to claim 1, characterized in that: The battery substrate includes a second edge region, which is located on a side of the middle region away from the first edge region; in the second edge region, a plurality of the second fine grids are arranged in sequence along the first direction; and the first fine grids avoid the second edge region.

10. The back contact cell according to claim 9, characterized in that: The battery substrate comprises a second edge, and the second edge extends along the second direction; the distance between the second fine grid closest to the second edge and the second edge is 0.2 mm to 2 mm.

11. The back contact cell according to claim 10, characterized in that: The distance between the first fine grid closest to the second edge and the second edge is 2 mm to 6 mm.

12. The back contact cell according to claim 9, characterized in that: In the second edge region, a distance between two adjacent second fine grids is smaller than a distance between two adjacent second fine grids in the middle region.

13. The back contact battery according to claim 9, characterized in that: The back contact cell further includes a first insulating member and a second insulating member; In the middle area, the first insulating member is located on the side of the first fine grid facing away from the battery substrate, and the second insulating member is located on the side of the second fine grid facing away from the battery substrate; the first insulating member and the second insulating member both avoid the first edge area and the second edge area.

14. The back contact cell according to claim 9, characterized in that: The back contact battery comprises a first main grid and a second main grid, the first main grid and the second main grid both extend along the first direction, the first main grid and the second main grid are alternately arranged along the second direction, the first main grid is connected to the first thin grid, the second main grid is connected to the second thin grid, and the first main grid and the second main grid have opposite polarities; The second main grid avoids the first edge area; The first main grid avoids the second edge area.

15. A battery assembly, characterized in that: The invention comprises several battery strings, wherein the battery strings include a plurality of back-contact batteries according to any one of claims 1 to 14.

16. The battery assembly according to claim 15, characterized in that: The battery string includes a plurality of the back-contact batteries, and two adjacent back-contact batteries are respectively a first battery cell and a second battery cell, and the first battery cell and the second battery cell overlap at a first edge region of the first battery cell.

17. The battery assembly according to claim 15, characterized in that: The battery string includes a plurality of the back-contact batteries, and the battery assembly further includes a first bus bar; Along the first direction, the back contact cell located at the first end of the cell string is a string head cell, and the first bus bar is located at a first edge region of the string head cell.

18. The battery assembly according to claim 17, characterized in that: The battery assembly further includes a first welding strip and a second welding strip, the first welding strip and the second welding strip both extend along the first direction, the first welding strip and the second welding strip are alternately arranged along the second direction, the first welding strip is conductively connected to the first fine grid of the battery cell in the string, and the second welding strip is conductively connected to the second fine grid of the battery cell in the string; In the first edge region of the string-headed solar cell, the first welding strip is arranged along the second direction; and the second welding strip avoids the first edge region of the string-headed solar cell.

19. The battery assembly according to claim 18, characterized in that: The battery assembly further includes a second bus bar; Along the first direction, the back contact cell located at the second end of the cell string is a cell sheet at the end of the string, and the second bus bar is located at a second edge region of the cell sheet at the end of the string.

20. The battery assembly according to claim 19, characterized in that The first welding strip is conductively connected to the first fine grid of the battery cell at the end of the string, and the second welding strip is conductively connected to the second fine grid of the battery cell at the end of the string; In the second edge region of the battery cell at the end of the string, the second welding strip is arranged along the second direction; and the first welding strip avoids the second edge region of the battery cell at the end of the string.

21. A photovoltaic system, characterized in that: Comprising a battery assembly as claimed in any one of claims 15 to 20.

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