Back contact battery assembly and photovoltaic system

Abstract

The utility model relates to the technical field of back contact batteries, and particularly discloses a back contact battery assembly and a photovoltaic system, the back contact battery assembly comprises a battery string, the battery string comprises battery pieces which are connected in series, the battery pieces comprise a first battery piece and a second battery piece which are arranged along a first direction, the first battery piece is arranged at the end part of the battery string, and the second battery piece is arranged at the end part of the battery string; the first confluence piece is arranged at one end, close to the first battery piece, of the second battery piece, the first confluence piece comprises a conductive main body and an insulating coating arranged on the outer surface of the conductive main body, the insulating coating comprises a back insulating part, the back insulating part is arranged on one side, facing the second battery piece, of the conductive main body, and the first confluence piece extends in the second direction; the first direction and the second direction are crossed, and the first welding strip is used for electrically connecting the conductive main body and the first battery piece. According to the utility model, the effective light-receiving area of the cell assembly can be increased, the conversion efficiency of the assembly can be improved, the observed area of the bus bar from one side of the light-receiving surface is smaller, even the bus bar can be completely hidden and is more beautiful, meanwhile, the production difficulty can be effectively reduced, the risks of cell piece cracking, fragmentation and pseudo soldering are reduced, and the reliability is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of back-contact batteries, in particular to a back-contact battery assembly and a photovoltaic system. Background Art

[0002] In existing back-contact battery modules, the series bus bars between adjacent series battery strings are usually placed at the edge of the battery module, and the parallel bus bars between adjacent parallel battery strings are usually placed in the reserved spacing area between the two battery strings. This results in a certain amount of space being required at the edge of the battery module to place the series bus bars, and a certain amount of space also being required between the two parallel battery strings to place the parallel bus bars. On the one hand, this reduces the effective light-receiving area of ​​the battery module and affects the module conversion efficiency. On the other hand, it affects the appearance of the battery cell.

[0003] In some products, the bus bar is installed in the middle position on the back of the battery cell, and an insulating strip is set between the bus bar and the battery cell. Although this setting can hide the bus bar, it is necessary to drill holes in the insulating strip or replace the bus bar with intermittent insulating blocks so that the bus bar can contact the same polarity welding strip on the battery cell, and at the same time be insulated from the opposite polarity welding strip and fine grid on the battery cell. This setting has high requirements on the drilling accuracy of the insulating strip and the arrangement position accuracy of the insulating block. It is difficult to produce and is prone to short circuit / cold solder joint due to position offset when the insulating strip is drilled or the insulating block is laminated. Utility Model Content

[0004] The purpose of the utility model is to provide a back contact battery assembly and a photovoltaic system in response to the existing technical status.

[0005] The utility model can increase the effective light-receiving area of ​​the battery assembly and improve the conversion efficiency of the assembly. The area of ​​the busbar observed from the light-receiving side is smaller and can even be completely hidden, which is more beautiful. At the same time, it can effectively reduce the difficulty of production, reduce the risk of battery cell cracks, fragments, and cold solder joints, and improve reliability.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] In one aspect, the present invention provides a back-contact battery assembly, comprising:

[0008] A battery string, wherein the battery string includes battery cells connected in series, the battery cells include a first battery cell and a second battery cell arranged along a first direction, the first battery cell is provided at an end of the battery string,

[0009] a first busbar, provided at one end of the second battery cell close to the first battery cell, the first busbar comprising a conductive body and an insulating coating provided on an outer surface of the conductive body, the insulating coating comprising a back insulating portion, the back insulating portion being provided on a side of the conductive body facing the second battery cell,

[0010] The first current collector extends along a second direction, and the first direction intersects the second direction.

[0011] The first welding ribbon is used to electrically connect the conductive body and the first battery cell.

[0012] In some embodiments, the thickness of the first current bus is 100 μm to 600 μm.

[0013] In some embodiments, the thickness of the insulating coating is 5 μm to 150 μm.

[0014] In some embodiments, the conductive body includes a first core material and a first tin layer outside the first core material, the conductive body is provided with a first connection area for connecting to the first soldering strip, and the first core material is provided with a rough surface on the side facing the first tin layer, and at least part of the rough surface is located at a corresponding position of the first connection area.

[0015] In some embodiments, the insulating coating further includes a front insulating portion, which is disposed on the side of the conductive body facing away from the second battery cell, and the front insulating portion is provided with an avoidance window for exposing the conductive body, and the first welding strip at least partially passes through the avoidance window to be electrically connected to the conductive body.

[0016] In some embodiments, the insulating coating further includes a lateral insulating portion, and the lateral insulating portion is provided at one end or both ends of the conductive body in the first direction.

[0017] In some embodiments, the conductive body is provided with a first connection area for connecting with the first welding ribbon, and a first adhesive layer is further provided on a surface of the first connection area.

[0018] In some embodiments, a second adhesive layer is provided outside the insulating coating.

[0019] In some embodiments, the insulating coating is any one of an acrylic layer, a silicone layer, an ethylene-vinyl acetate copolymer layer, a resin material layer, a polyimide layer, a polypropylene layer, and a polyethylene layer.

[0020] In some embodiments, the battery assembly includes at least one series-connected battery string group, each of the series-connected battery string groups includes two battery strings arranged along the second direction and arranged in series with each other.

[0021] Furthermore, in the same series-connected battery string group, the same first current bus extends from the second battery cell in one battery string to the second battery cell in another battery string.

[0022] In some embodiments, each battery string is provided with a fourth battery cell at one end away from the first battery cell, and a third battery cell is provided at one end of the fourth battery cell close to the first battery cell.

[0023] The battery assembly includes a parallel battery string group, and the same parallel battery string group includes at least two battery strings arranged along the first direction and arranged in parallel with each other, and the fourth battery cells in the two battery strings arranged in parallel with each other are arranged adjacent to each other in the first direction,

[0024] The battery assembly further comprises:

[0025] The second busbar is provided at an edge of the third battery cell in the battery string, and the second busbar is provided at an end of the third battery cell close to the fourth battery cell.

[0026] The second busbar includes a conducting body and an insulating material coating provided on an outer surface of the conducting body, wherein the insulating material coating includes a first insulating portion, and the first insulating portion is provided on a side of the conducting body facing the third battery cell.

[0027] The second current collector extends along a second direction, and the first direction intersects the second direction.

[0028] The second welding ribbon is used to electrically connect the second busbar, the fourth battery cell in the battery string, and the fourth battery cell in another battery string adjacent to the battery string in the first direction.

[0029] In another aspect, the present invention provides a back-contact battery assembly, comprising:

[0030] A parallel battery string group, wherein the same parallel battery string group includes at least two battery strings arranged in a first direction and arranged in parallel with each other, each battery string includes battery cells connected in series, the battery cells include a third battery cell and a fourth battery cell arranged in the first direction, the fourth battery cell is arranged at the end of the battery string, and the fourth battery cells in the two battery strings arranged in parallel are arranged adjacent to each other in the first direction,

[0031] The second busbar is provided at an edge of the third battery cell in the battery string, and the second busbar is provided at an end of the third battery cell close to the fourth battery cell.

[0032] The second busbar includes a conducting body and an insulating material coating provided on an outer surface of the conducting body, wherein the insulating material coating includes a first insulating portion, and the first insulating portion is provided on a side of the conducting body facing the third battery cell.

[0033] The second current collector extends along a second direction, and the first direction intersects the second direction.

[0034] The second welding ribbon is used to electrically connect the second busbar, the fourth battery cell in the battery string, and the fourth battery cell in another battery string adjacent to the battery string in the first direction.

[0035] In some embodiments, the second current bus has a thickness of 100 μm to 600 μm.

[0036] In some embodiments, the thickness of the insulating material coating is 5 μm to 150 μm.

[0037] In some embodiments, the conductive body includes a second core material and a second tin layer outside the second core material, the conductive body is provided with a second connection area for connecting to the second soldering strip, and the second core material is provided with a rough end surface on the side facing the second tin layer, and at least part of the rough end surface is located at a corresponding position of the second connection area.

[0038] In some embodiments, the insulating material coating further includes a second insulating portion, which is disposed on the side of the conductive body facing away from the third battery cell, and the second insulating portion is provided with an avoidance hollowing for exposing the conductive body, and the second welding strip at least partially passes through the avoidance hollowing to be electrically connected to the conductive body.

[0039] In some embodiments, the insulating material coating further includes a third insulating portion, and the third insulating portion is provided at one end or both ends of the conductive body in the first direction.

[0040] In some embodiments, the conductive body is provided with a second connection area for connecting with the second welding ribbon, and a third adhesive layer is further provided on the surface of the second connection area.

[0041] In some embodiments, a fourth adhesive layer is provided outside the insulating material coating.

[0042] In some embodiments, the insulating material coating is any one of an acrylic layer, a silicone layer, an ethylene-vinyl acetate copolymer layer, a resin material layer, a polyimide layer, a polypropylene layer, and a polyethylene layer.

[0043] Furthermore, the present invention provides a photovoltaic system including the above-mentioned back-contact cell assembly.

[0044] The beneficial effects of the present invention are:

[0045] 1) The built-in structure of the end collector of the present invention can, on the one hand, increase the effective light-receiving area of ​​the battery assembly, improve the conversion efficiency of the assembly, make the area of ​​the first collector observed from the light-receiving side smaller, or even completely hidden, and improve the overall aesthetics of the battery assembly; on the other hand, it can ensure that the first welding strip can be fully fitted and welded to the effective welding position of the first battery cell, avoiding the installation of the first collector causing insufficient welding between the first welding strip and the first battery cell, thereby affecting the current collection. During assembly, it is only necessary to place the entire first collector with an insulating coating on the end of the second battery cell close to the first battery cell, which effectively reduces the production precision requirements and production difficulty; furthermore, the built-in structure of the end collector of the present invention can It is suitable for both main-grid back-contact battery assemblies and non-main-grid back-contact battery assemblies, and has greater versatility. The stress at the end of the second battery cell close to the first battery cell is smaller than the outer edge of the last battery cell in the battery string during lamination. The integrated setting of the insulating coating and the conductive body can ensure that the first busbar performs normal busbar and insulation functions while making the overall thickness of the first busbar much lower than the sum of the thicknesses of the separately set busbars and insulating strips, thereby reducing the relative height distance from the connection between the first busbar and the first welding strip to the first battery cell, avoiding the risks of fragments, cracks, and cold solder joints caused by the large relative height distance between the connection between the busbar and the welding strip and the first battery cell, and the reliability of the back-contact battery assembly is good.

[0046] 2) The built-in structure of the intermediate busbar of the present invention can, on the one hand, increase the effective light-receiving area of ​​the battery assembly, improve the conversion efficiency of the assembly, make the area of ​​the second busbar observed from the light-receiving side smaller, or even completely hidden, and improve the overall aesthetics of the battery assembly; on the other hand, it can ensure that the second welding strip can be fully fitted and welded to the effective welding position of the fourth battery cell, avoiding the installation of the second busbar causing insufficient welding between the second welding strip and the fourth battery cell and affecting the current collection. During assembly, it is only necessary to place the entire second busbar with the insulating material coating on the end of the third battery cell close to the fourth battery cell, which effectively reduces the production precision requirements and production difficulty; furthermore, the built-in structure of the intermediate busbar of the present invention can It is suitable for both main-grid back-contact battery assemblies and non-main-grid back-contact battery assemblies, and has greater versatility. The end of the third battery cell close to the fourth battery cell has less stress during lamination than the outer edge of the last battery cell in the battery string. The integrated setting of the insulating material coating and the conductive body can ensure that the second busbar performs normal busbar and insulation functions while making the overall thickness of the second busbar much lower than the sum of the thicknesses of the separately set busbars and insulating strips, thereby reducing the relative height distance from the connection between the second busbar and the second welding strip to the fourth battery cell, avoiding the risks of cracks, fragments, and cold solder joints caused by the large relative height distance from the connection between the busbar and the welding strip to the fourth battery cell, and the reliability of the back-contact battery assembly is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic structural diagram of the built-in structure of the end current collector of the back-contact battery assembly according to an embodiment of the present invention.

[0048] Figure 2 This is a cross-sectional view of the first current bus (including the back insulating portion) according to an embodiment of the present invention.

[0049] Figure 3 This is a cross-sectional view of the first current bus (including the back insulating portion and the front insulating portion) according to an embodiment of the present invention.

[0050] Figure 4 This is a cross-sectional view of the first current bus (including the back insulating portion and the side insulating portion) according to an embodiment of the present invention.

[0051] Figure 5 This is a cross-sectional view of a first current bus (including a back insulating portion, a front insulating portion, and a lateral insulating portion) according to an embodiment of the present invention.

[0052] Figure 6 This is a cross-sectional view of the first current collector (including the first adhesive layer) according to an embodiment of the present invention.

[0053] Figure 71 is a cross-sectional view of a first current collector (including a first adhesive layer and a second adhesive layer) according to an embodiment of the present invention.

[0054] Figure 8 This is a top view of an implementation of the front insulating part of an embodiment of the present utility model.

[0055] Figure 9 This is a top view of another implementation of the front insulating portion of an embodiment of the present utility model.

[0056] Figure 10 It is a structural schematic diagram of a back-contact battery assembly (including a first busbar and a second busbar) according to an embodiment of the present invention.

[0057] Figure 11 This is a schematic structural diagram of the built-in structure of the intermediate busbar of the back-contact battery assembly according to an embodiment of the present invention.

[0058] Figure 12 This is a cross-sectional view of the second current bus (including the first insulating portion) according to an embodiment of the present invention.

[0059] Figure 13 2 is a cross-sectional view of a second current bus (including a first insulating portion and a second insulating portion) according to an embodiment of the present invention.

[0060] Figure 14 2 is a cross-sectional view of the second current bus (including the first insulating portion and the third insulating portion) according to an embodiment of the present invention.

[0061] Figure 15 It is a cross-sectional view of the second current bus (including the first insulating portion, the second insulating portion and the third insulating portion) according to an embodiment of the present invention.

[0062] Figure 16 This is a cross-sectional view of the second current collector (including the third adhesive layer) according to an embodiment of the present invention.

[0063] Figure 17 2 is a cross-sectional view of the second manifold (including the third adhesive layer and the fourth adhesive layer) according to an embodiment of the present invention.

[0064] Figure 18 This is a top view of an implementation of the second insulating part of an embodiment of the present utility model.

[0065] Figure 19 This is a top view of another implementation of the second insulating portion of an embodiment of the present utility model. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present application and are not intended to limit the present application.

[0067] In the description of this application, the terms "first," "second," "third," "fourth," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature defined as "first," "second," "third," "fourth," etc. may explicitly or implicitly include one or more of the described features. In the description of this application, "plurality" means two or more, unless otherwise explicitly and specifically defined.

[0068] Example 1

[0069] See also Figures 1 to 2 As shown, this embodiment discloses a back contact battery assembly, comprising:

[0070] A battery string, wherein the battery string includes battery cells connected in series, wherein the battery cells include a first battery cell 11 and a second battery cell 12 arranged along a first direction, wherein the first battery cell 11 is provided at an end of the battery string,

[0071] The first busbar 2 is provided at one end of the second battery cell 12 close to the first battery cell 11. The first busbar 2 includes a conductive body 21 and an insulating coating 22 provided on the outer surface of the conductive body 21. The insulating coating 22 includes a back insulating portion 221. The back insulating portion 221 is provided on the side of the conductive body 21 facing the second battery cell 12.

[0072] The first current collector 2 is extended along the second direction, and the first direction and the second direction are intersected.

[0073] The first welding ribbon 41 is used to electrically connect the conductive body 21 and the first battery cell 11 .

[0074] It is understandable that in a battery string, the battery string may include two battery cells connected in series, three battery cells connected in series, or other larger numbers of battery cells. The specific number of battery cells to be connected in series can be determined based on actual usage.

[0075] In this embodiment, the first busbar 2 is an end busbar, and the first battery cell 11 is located at the end of the battery string. For ease of explanation, in this embodiment, the end where the first battery cell 11 is located is recorded as the tail end of the battery string, that is, in the first direction, the first battery cell 11 is the last battery cell of the battery string, and the second battery cell 12 is the second to last battery cell of the battery string. It is not difficult to understand that the end where the first battery cell 11 is located can also be recorded as the head end of the battery string, which will not be repeated here.

[0076] Optionally, in the same battery string, adjacent battery cells can be connected in series by means of welding strips, conductive adhesives, etc., and adjacent battery cells can be arranged at intervals or partially stacked (ie, in a stacking manner).

[0077] The insulating coating 22 can be covered on the conductive body 21 by lamination, coating, heat shrinkage or other processes.

[0078] In one embodiment, see Figure 1 As shown, adjacent battery cells are connected by series welding ribbons 51. Specifically, the series welding ribbons 51 include first series welding ribbons 511 and second series welding ribbons 512. In the first direction, the first series welding ribbons 511 and the second series welding ribbons 512 are alternately arranged. In the second direction, the first series welding ribbons 511 and the second series welding ribbons 512 are alternately arranged. In a battery string, the Nth battery cell, the N+1th battery cell, and the N+2th battery cell (N is a positive integer greater than 1) are arranged in sequence along the first direction, wherein the positive electrode welding point of the Nth battery cell and the negative electrode welding point of the N+1th battery cell are connected in series through multiple first series welding ribbons 511, and the positive electrode welding point of the N+1th battery cell and the negative electrode welding point of the N+2th battery cell are connected in series through multiple second series welding ribbons 512.

[0079] During assembly, the battery cells in the battery string are connected in series with each other, and the first busbar 2 is arranged at one end of the second battery cell 12 close to the first battery cell 11, wherein the first busbar 2 is insulated from the grid lines, welding strips, welding points, etc. on the second battery cell 12 through the back insulation part 221, and is electrically connected to the first welding strip 41 through the conductive body 21, and the main body of the first welding strip 41 is electrically connected to the effective welding position of the first battery cell 11, thereby enabling the first busbar 2 to draw out the current of the battery string and ensuring that the conductive body 21 of the first busbar 2 and the second battery cell 12 are insulated from each other.

[0080] First of all, in the present invention, the first busbar 2 is arranged on the second battery cell 12, and the conductive body 21 of the first busbar 2 is insulated from the grid lines, welding strips, welding points, etc. on the second battery cell 12 by the back insulating portion 221 of the insulating coating 22. On the one hand, there is no need to reserve space at the edge of the battery assembly for placing the busbar, and the battery assembly can reserve more space for installing battery cells, so that the effective light-receiving area of ​​the battery assembly is larger and the assembly conversion efficiency is higher. On the other hand, when observing from the light-receiving surface (or "front") of the battery cell, the area of ​​the first busbar 2 observed is smaller, and it can even be completely blocked by the battery cell, and the overall aesthetics of the battery assembly is better.

[0081] Secondly, compared to setting the bus bar in the middle position on the back of the battery cell, the first bus bar 2 of the utility model is set at one end of the second battery cell 12 close to the first battery cell 11, and the first welding strip 41 can be fully fitted and welded with the effective welding position of the first battery cell 11, so as to avoid the installation of the first bus bar 2 causing insufficient welding between the first welding strip 41 and the first battery cell 11 and affecting the current collection. At the same time, after being welded to the first battery cell 11, the first welding strip 41 can be directly connected to the conductive body 21 of the first bus bar 2. Combined with the integrated setting of the insulating coating 22 and the conductive body 21, it is possible to ensure that the first bus bar 2 can lead out the battery string current on the basis of ensuring that the first bus bar 2 is connected to the second battery cell 12. The welding strips, grid lines and welding points are insulated, and there is no need to set up additional insulating strips that need to be processed by opening holes or intermittent insulating blocks. During assembly, it is only necessary to place the first busbar 2 with the insulating coating 22 on the end of the second battery cell 12 close to the first battery cell 11, which effectively reduces the production precision requirements and production difficulty, and can avoid short circuits / cold solder joints caused by position offset when the insulating strip is opened or position offset when the insulating blocks are laminated. Compared with the method of separately setting the busbar and the insulating strip, the utility model adopts an integrated setting of the insulating coating 22 and the conductive body 21, which can avoid problems such as short circuits / cold solder joints caused by relative offset between the busbar and the insulating strip in the first direction during the preparation process, thereby increasing product stability and yield.

[0082] Furthermore, when the bus bar is set at the outer edge of the last cell in the battery string, that is, when the first cell 11 is away from one end of the second cell 12, since the outer edge of the last cell in the battery string is close to the edge of the battery assembly, the stress there is relatively large during lamination, which is prone to defects such as fragments. At the same time, the installation of the bus bar will affect the welding between the first welding ribbon 41 and the first cell 11. The first welding ribbon 41 cannot be welded to the first cell 11 at the position covered by the bus bar, resulting in insufficient welding between the first welding ribbon 41 and the first cell 11 and poor current collection. This situation is particularly serious when the battery assembly is a main grid back contact battery assembly.

[0083] In contrast, the built-in structure of the end busbar of the present invention can be applied to battery assemblies with main grid back contact and battery assemblies without main grid back contact, and is more versatile. Moreover, on the one hand, the stress at the end of the second battery cell 12 close to the first battery cell 11 is smaller than the outer edge of the last battery cell in the battery string during lamination. On the other hand, compared with the method of separately setting the busbar and the insulating strip, the present invention adopts an integrated arrangement of the insulating coating 22 and the conductive body 21, which can ensure that the first busbar 2 performs the normal busbar and insulation functions while making the overall thickness of the first busbar 2 much lower than the sum of the thicknesses of the separately set busbar and the insulating strip, thereby reducing the relative height distance between the connection between the first busbar 2 and the first welding strip 41 and the first battery cell 11, avoiding the risk of cracks, fragments, and cold solder joints caused by the large relative height distance between the connection between the busbar and the welding strip and the first battery cell 11, and improving the reliability of the back contact battery assembly.

[0084] In some embodiments, the thickness of the first current collector 2 is 100 μm to 600 μm.

[0085] Illustratively, the thickness of the first busbar 2 is 100μm, 120μm, 150μm, 180μm, 200μm, 220μm, 250μm, 280μm, 300μm, 320μm, 350μm, 380μm, 400μm, 420μm, 450μm, 480μm, 500μm, 520μm, 550μm, 580μm or 600μm, but is not limited thereto.

[0086] The thickness of the first busbar 2 should not be too thick, otherwise it will easily increase the risk of cracks, fragments, and cold solder joints. The thickness of the first busbar 2 should not be too thin, otherwise it will be difficult to ensure the normal function of the current collecting function of the conductive body 21 and the insulation function of the insulating coating 22 in the first busbar 2.

[0087] In some embodiments, the thickness of the insulating coating 22 is 5 μm to 150 μm.

[0088] Illustratively, the thickness of the insulating coating 22 is 5 μm, 25 μm, 50 μm, 80 μm, 100 μm, 120 μm or 150 μm, but is not limited thereto.

[0089] The thickness of the insulating coating 22 should not be too thin, otherwise it will be difficult to ensure the insulation performance. The thickness of the insulating coating 22 should not be too thick, otherwise it will increase the overall thickness of the first busbar 2 and easily increase the risk of cracks, fragments, and cold solder joints.

[0090] In some embodiments, see Figure 3 and Figure 5As shown, the conductive body 21 includes a first core material 211 and a first tin layer 212 outside the first core material 211. The conductive body 21 is provided with a first connection area 213 for connecting with the first soldering strip 41. The first core material 211 is provided with a rough surface on the side facing the first tin layer 212, and at least part of the rough surface is located at a corresponding position of the first connection area 213.

[0091] Among them, see Figure 3 and Figure 5 As shown, the first tin layer 212 may cover the entire surface or a portion of the surface of the first core material 211 .

[0092] The first tin layer 212 can improve welding performance, but during use, the tin material layer is easily melted and flowed due to thermal effects (also known as tinning phenomenon). If the flow displacement of the tin material layer is too large, it is easy to cause the tin material layer to form an electrical connection with other conductive materials, thereby causing a short circuit.

[0093] In this embodiment, by roughening the surface of the first core material 211 to form a surface with a certain roughness (rough surface), the friction between the first core material 211 and the first tin layer 212 can be increased, thereby reducing the flow displacement of the tin material layer, reducing the risk of short circuit, and improving the reliability of the back contact battery assembly.

[0094] In one embodiment, the rough surface is only located in the first connection area 213 on the conductive body 21 connected to the first welding strip 41, that is, the surface of the first core material 211 is locally roughened, and this treatment method has a smaller treatment area.

[0095] In another embodiment, the surfaces of the first core material 211 are all rough surfaces, that is, the surfaces of the first core material 211 are uniformly roughened. This treatment method does not require special positioning of the to-be-treated position.

[0096] The first core material 211 may be a copper core, and the first tin layer 212 may be a single tin layer or a tin alloy layer. Preferably, the first tin layer 212 is a tin alloy layer. For example, the tin alloy layer may be a SnPb layer, a SnBi layer, or a SnAg layer, but is not limited thereto. By using a tin alloy layer, the tin content in the tin layer is reduced, thereby reducing the flow displacement of the first tin layer 212 without affecting the soldering effect, thereby reducing the risk of short circuits easily caused by the tin oxidation phenomenon.

[0097] In some embodiments, see Figure 3 、 Figure 5 、 Figure 8 and Figure 9As shown, the insulating coating 22 also includes a front insulating portion 222, which is arranged on the side of the conductive body 21 facing away from the second battery cell 12, and the front insulating portion 222 is provided with an avoidance window for exposing the conductive body 21, and the first welding strip 41 at least partially passes through the avoidance window to be electrically connected to the conductive body 21.

[0098] By providing a front insulating portion 222 with an avoidance window on the conductive body 21, the coverage area of ​​the insulating coating 22 outside the first tin layer 212 is increased. Without affecting the electrical conductivity between the first welding strip 41 and the conductive body 21, the flow displacement of the first tin layer 212 can be further limited, thereby reducing the short circuit risk easily caused by the tin-plating phenomenon.

[0099] The setting of the avoidance window prevents the insulating coating 22 from covering the position where the first welding strip 41 and the conductive body 21 are welded to each other, thereby preventing the insulating coating 22 from interfering with the electrical conduction between the first welding strip 41 and the conductive body 21 .

[0100] Preferably, the front insulating portion 222 includes insulating areas arranged at intervals along the second direction on the conductive body 21, and the conductive body 21 is provided with a first connection area 213 for connecting to the first welding strip 41. The first connection area 213 is formed between adjacent insulating areas, and the width of the first connection area 213 in the second direction is greater than the width of the first welding strip 41, thereby reducing the risk of short circuit easily caused by the tinning phenomenon while reducing the production precision requirements for setting the front insulating portion 222 on the conductive body 21.

[0101] In some embodiments, see Figures 4 to 7 As shown, the insulating coating 22 further includes a lateral insulating portion 223 , and the lateral insulating portion 223 is provided at one end or both ends of the conductive body 21 in the first direction.

[0102] Preferably, the lateral insulating portions 223 are provided at both ends of the conductive body 21 in the first direction, which can further limit the flow displacement of the first tin layer 212 and reduce the short circuit risk easily caused by the tin oxidation phenomenon.

[0103] In some embodiments, the lateral insulating portion 223 is connected to the front insulating portion 222 and the back insulating portion 221, respectively, so that the surface areas of the conductive body 21 except the first connection area 213 are covered by the insulating coating 22, which can further limit the flow displacement of the first tin layer 212 and reduce the short circuit risk easily caused by the tin-plating phenomenon.

[0104] In some embodiments, see Figure 1 、 Figure 6 and Figure 10As shown, the conductive body 21 is provided with a first connection area 213 for connecting with the first welding strip 41 , and a first adhesive layer 231 is further provided on the surface of the first connection area 213 .

[0105] At the location of the first connection area 213, the temperature is high when the conductive body 21 and the first welding strip 41 are welded, making it more likely for tinning to occur in this area. The provision of the first adhesive layer 231 can further limit the flow displacement of the first tin layer 212, while also playing the role of bonding the first welding strip 41, thereby ensuring the stability of the connection between the conductive body 21 and the first welding strip 41.

[0106] In some embodiments, see Figure 1 、 Figure 7 and Figure 10 As shown, a second adhesive layer 232 is provided on the outside of the insulating coating 22 .

[0107] The second adhesive layer 232 can form a second layer of protection outside the insulating coating 22 , thereby increasing the effect of limiting the flow and displacement of the first tin layer 212 and reducing the risk of short circuits caused by the tin-plating phenomenon.

[0108] In some embodiments, the insulating coating 22 is any one of an acrylic layer, a silicone layer, an ethylene-vinyl acetate copolymer layer, a resin material layer, a polyimide layer, a polypropylene layer, and a polyethylene layer, so that the insulating coating 22 has better insulating properties.

[0109] In some embodiments, see Figure 1 and Figure 10 As shown, the battery assembly includes at least one series-connected battery string group 100, each of the series-connected battery string groups 100 includes two battery strings arranged along the second direction and connected in series with each other.

[0110] Furthermore, in the same series-connected battery string group 100 , the same first current bus 2 extends from the second battery cell 12 in one battery string to the second battery cell 12 in another battery string.

[0111] For further information, see Figure 1 As shown, the first welding strip 41 includes a first positive electrode welding strip 411 and a first negative electrode welding strip 412. The same first busbar 2 is electrically connected to the first positive electrode welding strip 411 in one battery string and electrically connected to the first negative electrode welding strip 412 in another battery string, so that adjacent battery strings are connected in series.

[0112] Exemplarily, the same series battery string group 100 includes a first battery string 10A and a second battery string 10B, and the first welding strip 41 includes a first positive electrode welding strip 411 (connecting the positive electrode grid line) and a first negative electrode welding strip 412 (connecting the negative electrode grid line). In the same series battery string group 100, the same first busbar 2 extends from the second battery cell 12 in the first battery string 10A to the second battery cell 12 in the second battery string 10B, and in the first battery string 10A, the first busbar 2 is electrically connected to the first positive electrode welding strip 411 on the first battery cell 11, and in the second battery string 10B, the first busbar 2 is electrically connected to the first negative electrode welding strip 412 on the first battery cell 11.

[0113] In one embodiment, the battery assembly includes a parallel battery string group 200, and the same parallel battery string group 200 includes at least two battery strings arranged along a first direction and arranged in parallel with each other, and a spacing area is set between the two battery strings arranged in parallel with each other, and an intermediate bus bar is provided in the spacing area. The intermediate bus bar is used to connect two battery strings arranged adjacent to each other in parallel in the first direction. That is, the built-in structure of the end busbar of the utility model can cooperate with the conventional intermediate busbar installation structure.

[0114] In another more preferred embodiment, see Figures 10 to 12 As shown, the end collector built-in structure of the present invention can be matched with the middle collector built-in structure of the present invention, specifically:

[0115] Each battery string has a fourth battery cell 14 at one end away from the first battery cell 11 , and a third battery cell 13 at one end of the fourth battery cell 14 close to the first battery cell 11 .

[0116] The battery assembly includes a parallel battery string group 200, and the same parallel battery string group 200 includes at least two battery strings arranged in a first direction and arranged in parallel with each other, and the fourth battery cells 14 in the two battery strings arranged in parallel with each other are arranged adjacent to each other in the first direction.

[0117] The battery assembly further comprises:

[0118] The second busbar 3 is provided at an edge of the third battery cell 13 in the battery string, and the second busbar 3 is provided at an end of the third battery cell 13 close to the fourth battery cell 14.

[0119] The second busbar 3 includes a conductive body 31 and an insulating material coating 32 provided on the outer surface of the conductive body 31. The insulating material coating 32 includes a first insulating portion 321. The first insulating portion 321 is provided on a side of the conductive body 31 facing the third battery cell 13.

[0120] The second current collector 3 is extended along a second direction, and the first direction and the second direction are intersected.

[0121] The second welding ribbon is used to electrically connect the second current bus 3 , the fourth battery cell 14 in the battery string, and the fourth battery cell 14 in another battery string adjacent to the battery string in the first direction.

[0122] For ease of explanation, the third battery string 20A and the fourth battery string 20B connected in parallel in the same parallel battery string group 200 are taken as an example, wherein the third battery string 20A is the battery string where the second bus 3 is located:

[0123] The third battery cell 13 in the third battery string 20A is recorded as the third battery cell 13A, the fourth battery cell 14 is recorded as the fourth battery cell 14A, the third battery cell 13 in the fourth battery string 20B is recorded as the third battery cell 13B, the fourth battery cell 14 is recorded as the fourth battery cell 14B, the third battery string 20A and the fourth battery string 20B are arranged along the first direction, and the fourth battery cell 14A and the fourth battery cell 14B are arranged adjacent to each other in the first direction.

[0124] The battery pack also includes:

[0125] The second busbar 3 is provided at the edge of the third battery cell 13A in the third battery string 20A, and the second busbar 3 is provided at one end of the third battery cell 13A close to the fourth battery cell 14A.

[0126] The second busbar 3 includes a conductive body 31 and an insulating material coating 32 provided on the outer surface of the conductive body 31. The insulating material coating 32 includes a first insulating portion 321. The first insulating portion 321 is provided on a side of the conductive body 31 facing the third battery cell 13.

[0127] The second current collector 3 is extended along a second direction, and the first direction and the second direction are intersected.

[0128] The second welding ribbon is used to electrically connect the second busbar 3 , the fourth battery cell 14A, and the fourth battery cell 14B. That is, the same second welding ribbon extends from the fourth battery cell 14B to the fourth battery cell 14A and the second busbar 3 in sequence.

[0129] Furthermore, the second welding strip includes a second positive electrode welding strip and a second negative electrode welding strip, and the fourth battery cell 14A, the fourth battery cell 14B and the second busbar 3 are electrically connected via the second positive electrode welding strip or the second negative electrode welding strip.

[0130] On the one hand, the built-in structure of the intermediate busbar of the present invention can increase the effective light-receiving area of ​​the battery assembly, improve the conversion efficiency of the assembly, make the area of ​​the second busbar 3 observed from the light-receiving side smaller, or even completely hidden, and improve the overall aesthetics of the battery assembly; on the other hand, it can ensure that the second welding strip can be fully fitted and welded to the effective welding position of the fourth battery cell 14, and avoid the installation of the second busbar 3 causing insufficient welding between the second welding strip and the fourth battery cell 14, thereby affecting the current collection. During assembly, it is only necessary to place the entire second busbar 3 with the insulating material coating 32 on the end of the third battery cell 13 close to the fourth battery cell 14, which effectively reduces the production precision requirements and production difficulty; furthermore, the built-in structure of the intermediate busbar of the present invention can be suitable for It is used for battery assemblies with main grid back contact and battery assemblies without main grid back contact, and has stronger versatility. The stress at the end of the third battery cell 13 close to the fourth battery cell 14 is smaller than the outer edge of the last battery cell in the battery string during lamination. The integrated setting of the insulating material coating 32 and the conductive body 31 can ensure that the second busbar 3 performs normal bus and insulation functions while making the overall thickness of the second busbar 3 much lower than the sum of the thicknesses of the separately set busbar and insulating strip, thereby reducing the relative height distance from the connection between the second busbar 3 and the second welding strip to the fourth battery cell 14, avoiding the risks of cracks, fragments, and cold welding caused by the large relative height distance from the connection between the busbar and the welding strip to the fourth battery cell 14, and the reliability of the back contact battery assembly is good.

[0131] The built-in structure of the end collector of the present invention cooperates with the built-in structure of the middle collector of the present invention to increase the effective light-receiving area of ​​the battery assembly, improve the conversion efficiency of the assembly, improve the overall aesthetics and reliability of the battery assembly, effectively reduce the production precision requirements and production difficulty, and improve production efficiency.

[0132] Furthermore, the present invention provides a photovoltaic system including the above-mentioned back-contact cell assembly.

[0133] Example 2

[0134] See also Figures 10 to 12 As shown, this embodiment discloses a back contact battery assembly, comprising:

[0135] A parallel battery string group 200 includes at least two battery strings arranged in a first direction and arranged in parallel with each other, each battery string includes battery cells connected in series, and the battery cells include a third battery cell 13 and a fourth battery cell 14 arranged in the first direction. The fourth battery cell 14 is arranged at the end of the battery string, and the fourth battery cells 14 in the two battery strings arranged in parallel are arranged adjacent to each other in the first direction.

[0136] The second busbar 3 is provided at an edge of the third battery cell 13 in the battery string, and the second busbar 3 is provided at an end of the third battery cell 13 close to the fourth battery cell 14.

[0137] The second busbar 3 includes a conductive body 31 and an insulating material coating 32 provided on the outer surface of the conductive body 31. The insulating material coating 32 includes a first insulating portion 321. The first insulating portion 321 is provided on a side of the conductive body 31 facing the third battery cell 13.

[0138] The second current collector 3 is extended along a second direction, and the first direction and the second direction are intersected.

[0139] The second welding ribbon is used to electrically connect the second current bus 3 , the fourth battery cell 14 in the battery string, and the fourth battery cell 14 in another battery string adjacent to the battery string in the first direction.

[0140] In this embodiment, the second busbar 3 is an intermediate busbar.

[0141] For ease of explanation, the third battery string 20A and the fourth battery string 20B connected in parallel in the same parallel battery string group 200 are taken as an example, wherein the third battery string 20A is the battery string where the second bus 3 is located:

[0142] The third battery cell 13 in the third battery string 20A is recorded as the third battery cell 13A, the fourth battery cell 14 is recorded as the fourth battery cell 14A, the third battery cell 13 in the fourth battery string 20B is recorded as the third battery cell 13B, the fourth battery cell 14 is recorded as the fourth battery cell 14B, the third battery string 20A and the fourth battery string 20B are arranged along the first direction, and the fourth battery cell 14A and the fourth battery cell 14B are arranged adjacent to each other in the first direction.

[0143] The battery pack also includes:

[0144] A parallel battery string group 200 includes a third battery string 20A and a fourth battery string 20B arranged in parallel along a first direction, each battery string includes battery cells connected in series, and the battery cells include a third battery cell 13 and a fourth battery cell 14 arranged along the first direction. The fourth battery cell 14 is arranged at the end of the battery string, and the fourth battery cells 14 in the third battery string 20A and the fourth battery string 20B are arranged adjacent to each other in the first direction.

[0145] The second busbar 3 is provided at the edge of the third battery cell 13A in the third battery string 20A, and the second busbar 3 is provided at one end of the third battery cell 13A close to the fourth battery cell 14A.

[0146] The second busbar 3 includes a conductive body 31 and an insulating material coating 32 provided on the outer surface of the conductive body 31. The insulating material coating 32 includes a first insulating portion 321. The first insulating portion 321 is provided on a side of the conductive body 31 facing the third battery cell 13A.

[0147] The second current collector 3 is extended along a second direction, and the first direction and the second direction are intersected.

[0148] The second welding ribbon is used to electrically connect the second busbar 3 , the fourth battery cell 14A, and the fourth battery cell 14B. That is, the same second welding ribbon extends from the fourth battery cell 14B to the fourth battery cell 14A and the second busbar 3 in sequence.

[0149] Furthermore, the second welding strip includes a second positive electrode welding strip and a second negative electrode welding strip, and the fourth battery cell 14A, the fourth battery cell 14B and the second busbar 3 are electrically connected via the second positive electrode welding strip or the second negative electrode welding strip.

[0150] First, in the present invention, the second busbar 3 is arranged on the third battery cell 13A, and the conductive body 31 of the second busbar 3 is insulated from the grid lines, welding strips, welding points, etc. on the third battery cell 13A by the back insulating portion 221 of the insulating material coating 32. On the one hand, there is no need to reserve space on the edge of the battery assembly for placing the busbar, and the battery assembly can reserve more space for installing battery cells, so that the effective light-receiving area of ​​the battery assembly is larger and the assembly conversion efficiency is higher. On the other hand, when observed from the light-receiving surface (or "front") of the battery cell, the area of ​​the second busbar 3 observed is smaller, and it can even be completely blocked by the battery cell, and the overall aesthetics of the battery assembly is better.

[0151] Secondly, compared to setting the bus bar in the middle position on the back of the battery cell, the second busbar 3 of the utility model is set at one end of the third battery cell 13A close to the fourth battery cell 14A. The second welding strip can be fully fitted and welded with the effective welding position of the fourth battery cell 14A, thereby avoiding the installation of the second busbar 3 causing insufficient welding between the second welding strip and the fourth battery cell 14A, thereby affecting the current collection. At the same time, after the second welding strip is welded to the fourth battery cell 14A, it can be directly connected to the conductive body 31 of the second busbar 3. Combined with the integrated setting of the insulating material coating 32 and the conductive body 31, it can ensure that the second busbar 3 can lead out the battery string current on the basis of ensuring that the second busbar 3 is connected to the welding strip on the third battery cell 13A. , grid lines and welding points, etc., without the need to set up additional insulating strips that need to be processed by opening holes or intermittent insulating blocks. During assembly, it is only necessary to place the second busbar 3 with the insulating material coating 32 on the end of the third battery cell 13A close to the fourth battery cell 14A, which effectively reduces the production precision requirements and production difficulty, and can avoid short circuits / cold solder joints caused by position offset when the insulating strip is opened or position offset when the insulating blocks are laminated. Compared with the method of separately arranging the busbar and the insulating strip, the utility model adopts an integrated arrangement of the insulating material coating 32 and the conductive body 31, which can avoid problems such as short circuits / cold solder joints caused by the relative offset of the busbar and the insulating strip in the first direction during the preparation process, thereby increasing product stability and yield.

[0152] Furthermore, when the bus bar is set at the outer edge of the last cell in the battery string, that is, the fourth cell 14A is away from one end of the third cell 13A, since the outer edge of the last cell in the battery string is close to the edge of the battery assembly, the stress there is relatively large during lamination, which is prone to defects such as fragments. At the same time, the installation of the bus bar will affect the welding between the second welding ribbon and the fourth cell 14A. The second welding ribbon cannot be welded to the fourth cell 14A at the position covered by the bus bar, resulting in insufficient welding between the second welding ribbon and the fourth cell 14A and poor current collection. This situation is particularly serious when the battery assembly is a main grid back contact battery assembly.

[0153] In contrast, the built-in structure of the end busbar of the present invention can be applied to both main-grid back-contact battery assemblies and non-main-grid back-contact battery assemblies, and is more versatile. Moreover, on the one hand, the stress at the end of the third battery cell 13A close to the fourth battery cell 14A is smaller than the outer edge of the last battery cell in the battery string during lamination. On the other hand, compared with the method of separately setting the busbar and the insulating strip, the present invention adopts an insulating material coating 32 and a conductive body 31 as an integrated arrangement, which can ensure that the second busbar 3 performs the normal busbar and insulating function while making the overall thickness of the second busbar 3 much lower than the sum of the thicknesses of the separately set busbar and the insulating strip, thereby reducing the relative height distance from the connection between the second busbar 3 and the second welding strip to the fourth battery cell 14A, avoiding the risk of cracks, fragments, and cold solder joints caused by the large relative height distance from the connection between the busbar and the welding strip to the fourth battery cell 14A, and improving the reliability of the back-contact battery assembly.

[0154] In some embodiments, the thickness of the second current bus 3 is 100 μm to 600 μm.

[0155] Illustratively, the thickness of the second busbar 3 is 100μm, 120μm, 150μm, 180μm, 200μm, 220μm, 250μm, 280μm, 300μm, 320μm, 350μm, 380μm, 400μm, 420μm, 450μm, 480μm, 500μm, 520μm, 550μm, 580μm or 600μm, but is not limited thereto.

[0156] The thickness of the second busbar 3 should not be too thick, otherwise it will easily increase the risk of cracks, fragments, and cold solder joints. The thickness of the second busbar 3 should not be too thin, otherwise it will be difficult to ensure the normal function of the current collecting function of the conductive body 21 in the first busbar 2 and the insulation function of the insulating coating 22.

[0157] In some embodiments, the thickness of the insulating material coating 32 is 5 μm to 150 μm.

[0158] Exemplarily, the thickness of the insulating material coating 32 is 5 μm, 25 μm, 50 μm, 80 μm, 100 μm, 120 μm or 150 μm, but is not limited thereto.

[0159] The thickness of the insulating material coating 32 should not be too thin, otherwise it is difficult to ensure the insulation performance. The thickness of the insulating coating 22 should not be too thick, otherwise it will increase the overall thickness of the first busbar 2 and easily increase the risk of cracks, fragments, and cold solder joints.

[0160] In some embodiments, see Figure 13 and Figure 15As shown, the conductive body 31 includes a second core material 311 and a second tin layer 312 outside the second core material 311. The conductive body 31 is provided with a second connection area 313 for connecting with the second soldering strip. The second core material 311 is provided with a rough end surface on the side facing the second tin layer 312, and at least part of the rough end surface is located at the corresponding position of the second connection area 313.

[0161] Among them, see Figure 13 and Figure 15 As shown, the second tin layer 312 may cover the entire surface or a portion of the surface of the second core material 311 .

[0162] In this embodiment, by roughening the surface of the second core material 311 to form a surface with a certain roughness (rough end face), the friction between the second core material 311 and the second tin layer 312 can be increased, thereby reducing the flow displacement of the tin material layer, reducing the risk of short circuit, and improving the reliability of the back-contact battery assembly.

[0163] In one embodiment, the rough end surface is only located in the connection area of ​​the conductive body 21 connected to the second welding strip, that is, the surface of the second core material 311 is locally roughened, and this treatment method has a smaller treatment area.

[0164] In another embodiment, the surfaces of the second core material 311 are all roughened end surfaces, that is, the surfaces of the second core material 311 are uniformly roughened. This treatment method does not require special positioning of the to-be-treated position.

[0165] The second core material 311 may be a copper core, and the second tin layer 312 may be a single tin layer or a tin alloy layer. Preferably, the second tin layer 312 is a tin alloy layer. Exemplarily, the tin alloy layer may be a SnPb layer, a SnBi layer, or a SnAg layer, but is not limited thereto. By using a tin alloy layer, the tin content in the tin layer is reduced, thereby reducing the flow displacement of the second tin layer 312 without affecting the soldering effect, thereby reducing the risk of short circuits easily caused by the tin oxidation phenomenon.

[0166] In some embodiments, see Figure 13 、 Figure 15 、 Figure 18 and Figure 19 As shown, the insulating material coating 32 also includes a second insulating portion 322, which is arranged on the side of the conductive body 31 facing away from the third battery cell 13, and the second insulating portion 322 is provided with an avoidance hollowing for exposing the conductive body 31, and the second welding strip at least partially passes through the avoidance hollowing to be electrically connected to the conductive body 31.

[0167] By providing a second insulating portion 322 with a hollowed-out portion on the conductive body 31, the coverage area of ​​the insulating material coating 32 outside the second tin layer 312 is increased. Without affecting the electrical conductivity between the second soldering tape and the conductive body 31, the flow displacement of the second tin layer 312 can be further limited, thereby reducing the short circuit risk easily caused by the tin-plating phenomenon.

[0168] Preferably, the second insulating portion 322 includes insulating areas arranged at intervals along the second direction on the conductive body 31, and the conductive body 31 is provided with a second connection area 313 for connecting to the second welding strip. The second connection area 313 is formed between adjacent insulating areas, and the width of the second connection area 313 in the second direction is greater than the width of the second welding strip, thereby reducing the short circuit risk easily caused by the tinning phenomenon while reducing the production precision requirements for setting the front insulating portion 222 on the conductive body 31.

[0169] In some embodiments, see Figures 14 to 17 As shown, the insulating material coating 32 further includes a third insulating portion 323 , and the third insulating portion 323 is provided at one end or both ends of the conductive body 31 in the first direction.

[0170] Preferably, the third insulating portion 323 is provided at both ends of the conductive body 31 in the first direction, which can further limit the flow displacement of the second tin layer 312 and reduce the short circuit risk easily caused by the tin-plating phenomenon.

[0171] In some embodiments, the third insulating portion 323 is connected to the first insulating portion 321 and the second insulating portion 322, respectively, so that the surface areas of the conductive body 31 except the connection area are covered by the insulating coating 22, which can further limit the flow displacement of the second tin layer 312 and reduce the short circuit risk easily caused by the tin-plating phenomenon.

[0172] In some embodiments, see Figure 16 As shown, the conductive body 31 is provided with a second connection area 313 for connecting with the second welding ribbon, and a third adhesive layer 331 is further provided on the surface of the second connection area 313 .

[0173] The third adhesive layer 331 can further limit the flow displacement of the second tin layer 312 and simultaneously play a role in bonding the second soldering strip, thereby ensuring the stability of the connection between the conductive body 31 and the second soldering strip.

[0174] In some embodiments, see Figure 17 As shown, a fourth adhesive layer 332 is provided on the outside of the insulating material coating 32 .

[0175] The fourth adhesive layer 332 can form a second layer of protection outside the insulating material coating 32 , thereby increasing the effect of limiting the flow and displacement of the second tin layer 312 and reducing the risk of short circuits caused by the tin deposition phenomenon.

[0176] In some embodiments, the insulating material coating 32 is any one of an acrylic layer, a silicone layer, an ethylene-vinyl acetate copolymer layer, a resin material layer, a polyimide layer, a polypropylene layer, and a polyethylene layer.

[0177] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the structure and implementation principle of the back-contact battery described above can refer to the corresponding structure and implementation principle in the aforementioned embodiment 1, and will not be repeated here.

[0178] Of course, the above figures are only preferred embodiments of the present invention and are not intended to limit the scope of use of the present invention. Therefore, any equivalent changes based on the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A back contact battery assembly, characterized in that: include: A battery string, wherein the battery string includes battery cells connected in series, the battery cells include a first battery cell and a second battery cell arranged along a first direction, the first battery cell is provided at an end of the battery string, a first busbar, provided at one end of the second battery cell close to the first battery cell, the first busbar comprising a conductive body and an insulating coating provided on an outer surface of the conductive body, the insulating coating comprising a back insulating portion, the back insulating portion being provided on a side of the conductive body facing the second battery cell, The first current collector extends along a second direction, and the first direction intersects the second direction. The first welding ribbon is used to electrically connect the conductive body and the first battery cell.

2. The back contact battery assembly according to claim 1, characterized in that The thickness of the first current collector is 100 μm to 600 μm.

3. The back contact battery assembly according to claim 1, characterized in that The thickness of the insulating coating is 5 μm to 150 μm.

4. The back contact battery assembly according to claim 1, wherein: The conductive body includes a first core material and a first tin layer outside the first core material. The conductive body is provided with a first connection area for connecting to the first soldering strip. The first core material is provided with a rough surface on the side facing the first tin layer, and at least part of the rough surface is located at a corresponding position of the first connection area.

5. The back contact battery assembly according to claim 1, wherein: The insulating coating also includes a front insulating portion, which is arranged on the side of the conductive body facing away from the second battery cell, and the front insulating portion is provided with an avoidance window for exposing the conductive body, and the first welding strip at least partially passes through the avoidance window to be electrically connected to the conductive body.

6. The back contact battery assembly according to claim 1, wherein: The insulating coating further includes a lateral insulating portion, and the lateral insulating portion is provided at one end or both ends of the conductive body in the first direction.

7. The back contact battery assembly according to claim 1, characterized in that The conductive body is provided with a first connection area for connecting with the first welding strip, and a first adhesive layer is further provided on the surface of the first connection area.

8. The back contact battery assembly according to claim 7, characterized in that: A second adhesive layer is provided outside the insulating coating.

9. The back contact battery assembly according to claim 1, wherein: The insulating coating is any one of an acrylic layer, a silicone layer, an ethylene-vinyl acetate copolymer layer, a resin material layer, a polyimide layer, a polypropylene layer, and a polyethylene layer.

10. The back contact battery assembly according to claim 1, characterized in that: The battery assembly includes at least one series-connected battery string group, each of the series-connected battery string groups includes two battery strings arranged along the second direction and connected in series with each other, Furthermore, in the same series-connected battery string group, the same first current bus extends from the second battery cell in one battery string to the second battery cell in another battery string.

11. The back contact battery assembly according to claim 1, characterized in that: Each battery string has a fourth battery cell at one end away from the first battery cell, and a third battery cell at one end of the fourth battery cell close to the first battery cell. The battery assembly includes a parallel battery string group, and the same parallel battery string group includes at least two battery strings arranged along the first direction and arranged in parallel with each other, and the fourth battery cells in the two battery strings arranged in parallel with each other are arranged adjacent to each other in the first direction, The battery assembly further comprises: The second busbar is provided at an edge of the third battery cell in the battery string, and the second busbar is provided at an end of the third battery cell close to the fourth battery cell. The second busbar includes a conducting body and an insulating material coating provided on an outer surface of the conducting body, wherein the insulating material coating includes a first insulating portion, and the first insulating portion is provided on a side of the conducting body facing the third battery cell. The second current collector extends along a second direction, and the first direction intersects the second direction. The second welding ribbon is used to electrically connect the second busbar, the fourth battery cell in the battery string, and the fourth battery cell in another battery string adjacent to the battery string in the first direction.

12. A back contact battery assembly, characterized in that: include: A parallel battery string group, wherein the same parallel battery string group includes at least two battery strings arranged in a first direction and arranged in parallel with each other, each battery string includes battery cells connected in series, the battery cells include a third battery cell and a fourth battery cell arranged in the first direction, the fourth battery cell is arranged at the end of the battery string, and the fourth battery cells in the two battery strings arranged in parallel are arranged adjacent to each other in the first direction, The second busbar is provided at an edge of the third battery cell in the battery string, and the second busbar is provided at an end of the third battery cell close to the fourth battery cell. The second busbar includes a conducting body and an insulating material coating provided on an outer surface of the conducting body, wherein the insulating material coating includes a first insulating portion, and the first insulating portion is provided on a side of the conducting body facing the third battery cell. The second current collector extends along a second direction, and the first direction intersects the second direction. The second welding ribbon is used to electrically connect the second busbar, the fourth battery cell in the battery string, and the fourth battery cell in another battery string adjacent to the battery string in the first direction.

13. The back contact battery assembly according to claim 12, characterized in that The second current busbar has a thickness of 100 μm to 600 μm.

14. The back contact battery assembly according to claim 12, wherein: The thickness of the insulating material coating is 5 μm to 150 μm.

15. The back contact battery assembly according to claim 12, wherein: The conductive body includes a second core material and a second tin layer outside the second core material. The conductive body is provided with a second connection area for connecting to the second soldering strip. The second core material is provided with a rough end surface on the side facing the second tin layer, and at least part of the rough end surface is located at a corresponding position of the second connection area.

16. The back contact battery assembly according to claim 12, characterized in that The insulating material coating also includes a second insulating portion, which is arranged on the side of the conductive body facing away from the third battery cell, and the second insulating portion is provided with an avoidance hollowing for exposing the conductive body, and the second welding strip at least partially passes through the avoidance hollowing and is electrically connected to the conductive body.

17. The back contact battery assembly according to claim 12, wherein: The insulating material coating further includes a third insulating portion, and the third insulating portion is provided at one end or both ends of the conductive body in the first direction.

18. The back contact battery assembly according to claim 12, wherein: The conducting body is provided with a second connection area for connecting with the second welding strip, and a third adhesive layer is further provided on the surface of the second connection area.

19. The back contact battery assembly according to claim 18, characterized in that A fourth adhesive layer is provided outside the insulating material coating.

20. The back contact battery assembly according to claim 12, wherein: The insulating material coating is any one of an acrylic layer, a silicone layer, an ethylene-vinyl acetate copolymer layer, a resin material layer, a polyimide layer, a polypropylene layer, and a polyethylene layer.

21. A photovoltaic system, characterized in that: Comprising a back contact battery assembly according to any one of claims 1 to 20.

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