Preparation method of back contact battery assembly and back contact battery assembly

Abstract

The invention provides a preparation method of a back contact cell assembly and the back contact cell assembly, and relates to the technical field of solar cells, a long cell string is firstly prepared, confluence fixing glue layers are formed on the back surfaces of a first piece, a tail piece and a middle piece, and then a first interconnection strip and a second interconnection strip are arranged. A plurality of long battery strings are then laid on the substrate. And an insulating isolation strip is arranged on the second interconnection strip at the preset position. And then bus bars are arranged on the insulating isolating bars and the bus fixing adhesive layer, and finally, a back plate is laid and laminated welding is carried out. Compared with the prior art, the bus bar can be hidden on the back surface of the battery, so that the size of the battery is increased, the space utilization rate of the module is improved, and the power of the module is improved. And meanwhile, by preparing the bus bar fixing adhesive layer in advance, high-temperature welding on the edge of the battery piece when the bus bar is fixed in the conventional technology is avoided, the warping phenomenon of the battery piece can be effectively avoided, the risk of subfissure or piece cracking is reduced, and the quality and yield of the battery are improved.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and in particular to a method for preparing a back-contact solar cell assembly and a back-contact solar cell assembly. Background Art

[0002] Conventional back contact battery (BC battery, Back Contact) components are composed of multiple battery strings. The bus bar is used as a current extraction component and is connected to the head and tail interconnection bars of the battery string. In conventional layout design, the bus bar needs to occupy a certain space (such as Figure 1 As shown in the figure), the size of the battery will be limited and the power of the components will be limited.

[0003] Conventional back-contact cells also undergo high-temperature welding during the fabrication of interconnects and busbars. This requires high-temperature welding to achieve electrical connection and fixation between the busbars and interconnects. However, high-temperature welding equipment is complex, and performing high-temperature welding on the edges of the cell can easily cause cell warping, leading to hidden cracks or splinters in subsequent processes, impacting cell quality and yield. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a back-contact battery assembly and a back-contact battery assembly, which can increase the battery size, improve the assembly space utilization and power, and avoid warping of the battery cells, reduce the risk of hidden cracks or splits, and improve the battery quality and yield.

[0005] In a first aspect, the present invention provides a method for preparing a back-contact battery assembly, comprising: Prepare a long battery string, wherein the long battery string includes a plurality of back-contact battery cells arranged sequentially along a first direction, a busbar fixing adhesive layer intermittently arranged along a second direction is formed on the back surfaces of the first, last, and middle back-contact battery cells, and a first interconnection bar and a second interconnection bar intermittently arranged along the first direction are provided on the back surfaces of the plurality of back-contact battery cells, the first interconnection bar and the second interconnection bar being alternately arranged at intervals along the second direction at intermittent openings in the busbar fixing adhesive layer for connecting adjacent back-contact battery cells, the first direction being perpendicular to the second direction; Laying a plurality of the long battery strings on a substrate according to a preset pattern; An insulating isolation strip is provided on the second interconnecting strip at the intermittent opening of the busbar fixing adhesive layer, wherein the insulating isolation strip and the corresponding busbar fixing adhesive layer are arranged along the same straight line direction; A bus bar is provided on the insulating isolation bar and the bus fixing adhesive layer, wherein the insulating isolation bar is used to electrically isolate the bus bar from the second interconnection bar, and the bus fixing adhesive layer is used to bond and fix the bus bar so that the bus bar contacts the first interconnection bar; Laying a back sheet on the long battery string to form a battery assembly; The battery assembly is laminated and welded, so that the first interconnection bar and the second interconnection bar are welded and fixed to the back contact battery sheet, and the bus bar is welded and fixed to the first interconnection bar.

[0006] In an optional embodiment, the step of preparing a long battery string includes: Providing a plurality of back-contact solar cells arranged in series along a first direction; Printing a busbar fixing adhesive layer on the back side of the back contact battery cells of the first sheet, the last sheet and the middle sheet, wherein the busbar fixing adhesive layer is intermittently arranged along the second direction; A first interconnection bar and a second interconnection bar are alternately arranged on the back side of the plurality of back-contact battery cells along the second direction, so that the plurality of back-contact battery cells are connected in series through the first interconnection bar and the second interconnection bar to form a long battery string, wherein the first interconnection bar and the second interconnection bar are alternately arranged at the intermittent openings of the bus fixing adhesive layer.

[0007] In an optional embodiment, before the step of printing and forming a busbar fixing adhesive layer on the back surface of the back contact solar cells of the first sheet, the last sheet, and the middle sheet, the preparation method further comprises: An insulating adhesive layer, a solder paste layer, and an interconnect fixing adhesive layer are sequentially printed on the back side of the back contact solar cell; The interconnection fixing adhesive layer is used to fix the first interconnection bar and the second interconnection bar, and the interconnection fixing adhesive layer and the bus fixing adhesive layer are spaced apart.

[0008] In an optional embodiment, the interconnect fixing adhesive layer is a thermal fixing adhesive, and the bus fixing adhesive layer is a UV fixing adhesive; or the interconnect fixing adhesive layer is a UV fixing adhesive, and the bus fixing adhesive layer is a thermal fixing adhesive.

[0009] In an optional embodiment, the step of providing alternately distributed first interconnection bars and second interconnection bars on the back side of the plurality of back contact solar cells comprises: Alternately laying first interconnecting bars and second interconnecting bars along a second direction on the back sides of a plurality of back contact battery cells arranged along a first direction according to a preset pattern to form a first battery string; Second interconnection bars and first interconnection bars are alternately laid in sequence along the second direction on the back sides of the plurality of back contact battery sheets arranged along the first direction according to a preset pattern to form a second battery string.

[0010] In an optional embodiment, the step of laying a plurality of the long battery strings on a substrate according to a preset pattern includes: Providing a substrate with a front adhesive film layer; Laying the first battery string and the second battery string alternately on the substrate along the second direction; The first battery string and the second battery string are symmetrical in the second direction.

[0011] In an optional embodiment, the step of preparing a long battery string includes: Providing a plurality of back-contact solar cells arranged in series along a first direction; Alternately arranging first interconnection bars and second interconnection bars along a second direction on the back surfaces of the plurality of back-contact battery cells, so that the plurality of back-contact battery cells are connected in series through the first interconnection bars and the second interconnection bars to form a long battery string; A busbar fixing adhesive layer is formed on both sides of the first interconnection bar and the second interconnection bar on the back contact battery cells of the first, last and middle sheets, wherein the busbar fixing adhesive layer is intermittently arranged along the second direction and spaced apart from the first interconnection bar and the second interconnection bar.

[0012] In an optional embodiment, the step of providing an insulating isolation strip on the second interconnection strip at the intermittent opening of the busbar fixing adhesive layer includes: Delimiting an isolation area on the second interconnection bar according to the bus fixing adhesive layer, wherein a width of the isolation area along the first direction is greater than a width of the bus fixing adhesive layer; A layer of insulating isolation strip is laid on the top side and side wall of the second interconnection strip in the isolation area, wherein the insulating isolation strip is spaced apart from the bus fixing adhesive layer, and the thickness of the bus fixing adhesive layer is greater than or equal to the sum of the thickness of the second interconnection strip and the insulating isolation strip.

[0013] In an optional embodiment, the step of providing busbars on the insulating isolation bars and the busbar fixing adhesive layer includes: Laying busbars on the corresponding busbar fixing adhesive layers and the insulating isolation strips along the second direction, wherein the busbars are used to connect adjacent long battery strings, and the busbars on the back-contact battery sheets of the first and last sheets and the busbars on the back-contact battery sheets of the middle sheet are staggered along the second direction; Pressing down the bus bar so that the bus bar contacts the first interconnection bar; The bus fixing adhesive layer is cured.

[0014] In an optional embodiment, the step of aligning and laying the busbars on the corresponding busbar fixing adhesive layers and the insulating isolation bars along the second direction includes: Align the recess on the bottom side of the busbar with the insulating spacer; The busbars are laid on the corresponding busbar fixing adhesive layers and the insulating isolation strips.

[0015] In an optional embodiment, the step of laying a backsheet on the long battery string includes: Laying a backside adhesive film layer and a backsheet in sequence on the long battery string; The backside adhesive film layer covers the backsides of the plurality of back-contact battery cells and the busbars.

[0016] In an optional embodiment, the step of laminating and welding the battery assembly includes: The battery assembly is placed in a laminator for vacuuming and heating to a preset temperature, so that the first interconnection bar and the second interconnection bar are alloy-welded with the electrodes of the back contact battery sheet, and the bus bar is alloy-welded with the first interconnection bar.

[0017] In an optional embodiment, the preset temperature is between 135°C and 155°C.

[0018] In a second aspect, the present invention provides a back-contact battery assembly, which is prepared using the method for preparing a back-contact battery assembly as described in any of the above embodiments, and the back-contact battery assembly includes: substrate; A plurality of long battery strings laid on the substrate, each of the long battery strings comprising a plurality of back-contact battery cells arranged sequentially along a first direction, a busbar fixing adhesive layer intermittently arranged along a second direction formed on the back surfaces of the first, last, and middle back-contact battery cells, and first and second interconnecting bars intermittently arranged along the first direction provided on the back surfaces of the plurality of back-contact battery cells, the first and second interconnecting bars being alternately arranged at intervals along the second direction at intermittent openings in the busbar fixing adhesive layer for connecting adjacent back-contact battery cells, the first direction being perpendicular to the second direction; an insulating spacer strip provided on the second interconnecting strip at the intermittent opening of the busbar fixing adhesive layer, wherein the insulating spacer strip and the corresponding busbar fixing adhesive layer are arranged along the same straight line direction; The busbar is arranged on the insulating isolation bar and the busbar fixing adhesive layer, the insulating isolation bar is used to electrically isolate the busbar and the second interconnection bar, the busbar fixing adhesive layer is used to bond and fix the busbar, and the busbar is welded and fixed to the first interconnection bar.

[0019] In an optional embodiment, the plurality of long battery strings include a first battery string and a second battery string, the first battery string and the second battery string are alternately laid on the substrate in sequence along the second direction, and the first interconnection bar and the second interconnection bar on the first battery string and the first interconnection bar and the second interconnection bar on the second battery string are symmetrical structures in the second direction.

[0020] In an optional embodiment, each of the long battery strings includes 2N back-contact battery cells arranged in sequence along a first direction, wherein the back-contact battery cell of the first cell and the back-contact battery cell of the Nth cell are connected in series with each other, the back-contact battery cell of the N+1th cell and the back-contact battery cell of the last cell are connected in series with each other, and the back-contact battery cell of the Nth cell and the back-contact battery cell of the N+1th cell are connected in parallel with each other.

[0021] The beneficial effects of the embodiments of the present invention include: Embodiments of the present invention provide a method for preparing a back-contact cell and a back-contact cell. The method first prepares a long cell string consisting of a plurality of back-contact cells arranged sequentially along a first direction. A busbar fixing adhesive layer is formed on the backside of the first, last, and middle back-contact cells, intermittently arranged along a second direction. Furthermore, a first and second interconnecting bar are provided on the backside of the plurality of back-contact cells, with the first and second interconnecting bars being provided at the intermittent cuts in the busbar fixing adhesive layer. The plurality of long cell strings are then laid out on a substrate according to a predetermined pattern. Insulating strips are then provided on the second interconnecting bar at the intermittent cuts in the busbar fixing adhesive layer. A busbar is then provided on the insulating strip and the busbar fixing adhesive layer. The insulating strip electrically isolates the busbar from the second interconnecting bar, while the busbar fixing adhesive layer adheres and secures the busbar to the first interconnecting bar. Finally, a backplane is placed on the long cell string, and the resulting battery assembly is laminated and welded, completing the welding and securing of the first and second interconnecting bars to the back-contact cells, and between the busbars and the first interconnecting bar.

[0022] Compared with the prior art, the embodiment of the present invention can set the busbar on the insulating isolation strip and busbar fixing adhesive layer on the back of the back contact battery cell, and can hide the busbar on the back of the battery, thereby increasing the battery size, improving the component space utilization, and improving the component power. At the same time, by preparing the busbar fixing adhesive layer in advance, the busbar can be directly bonded and fixed through the busbar fixing adhesive layer when fixed, avoiding high-temperature welding before lamination, thereby avoiding the high-temperature welding of the battery cell edge when fixing the busbar in conventional technology. In addition, the use of a low-temperature lamination welding process to achieve the welding connection between the busbar and the interconnecting bar can effectively avoid the warping of the battery cell, reduce the risk of hidden cracks or splits, and improve the battery quality and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 Schematic diagram of the distribution structure of the back contact battery assembly in the prior art; Figure 2 A flowchart of a method for preparing a back-contact battery assembly according to an embodiment of the present invention; Figures 3 to 6 for Figure 2 Schematic diagram of the process flow of step S1; Figure 7 for Figure 2 Schematic diagram of the process flow of step S2; Figure 8 for Figure 2 Schematic diagram of the process flow of step S3; Figure 9 for Figure 8 A partial enlarged schematic diagram of position IX in the middle; Figure 10 for Figure 8 Partial cross-sectional view at AA in the middle; Figure 11 for Figure 2 Schematic diagram of the process flow of step S4; Figure 12 for Figure 11 Partial cross-sectional view at the middle BB; Figure 13 for Figure 11 A partial cross-sectional view of BB in another preferred embodiment; Figure 14 for Figure 2 Schematic diagram of the process flow of step S5; Figure 15 An exploded schematic diagram of a back-contact battery assembly provided by an embodiment of the present invention; Figure 16 A partial structural cross-sectional view of a back-contact battery assembly provided in an embodiment of the present invention.

[0025] Icons: 100-back contact battery assembly; 110-long battery string; 111-back contact battery cell; 112-first interconnection bar; 113-second interconnection bar; 114-interconnection fixing adhesive layer; 115-first battery string; 116-second battery string; 120-bus fixing adhesive layer; 130-insulating isolation strip; 140 substrate; 150-bus bar; 151-relief groove; 160-back plate. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0029] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0030] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0031] As disclosed in the background technology, in the prior art, back contact cells are usually designed as a semi-assembly design, with the busbar serving as a current extraction component connected to the head and tail interconnection bars of the battery string. In conventional layout designs, the busbar 150 needs to occupy a certain space (e.g. Figure 1 As shown in the figure), the size of the battery will be limited and the power of the components will be limited.

[0032] Furthermore, a solution has emerged to set the bus bar on the back side of the back-contact battery cell. However, this solution requires high-temperature welding when preparing the interconnection bars and bus bars to ensure that the bus bars and interconnection bars are welded and fixed. This high-temperature welding process will cause the local thermal stress of the battery cell to increase and easily cause the battery cell to warp. Hidden cracks or splits are likely to occur in subsequent processes, affecting the quality and yield of the battery.

[0033] In order to solve the above problems, an embodiment of the present invention provides a method for preparing a back-contact battery assembly and a back-contact battery assembly. It should be noted that the features in the embodiments of the present invention can be combined with each other without conflict.

[0034] See also Figure 2 An embodiment of the present invention provides a method for preparing a back-contact battery assembly 100, which is used to prepare the back-contact battery assembly 100. The method for preparing the back-contact battery assembly 100 can increase the battery size, improve the assembly space utilization and power, and avoid warping of the battery cells, reduce the risk of hidden cracks or splits, and improve the battery quality and yield.

[0035] The method for preparing the back-contact battery assembly 100 provided in an embodiment of the present invention includes the following steps: S1: preparing a long battery string 110 .

[0036] See also Figures 3 to 6 , wherein the long battery string 110 includes a plurality of back-contact battery cells 111 arranged in sequence along a first direction, and a bus fixing adhesive layer 120 intermittently arranged along a second direction is formed on the back side of the back-contact battery cells 111 of the first, last, and middle pieces, and a first interconnection bar 112 and a second interconnection bar 113 intermittently arranged along the first direction are provided on the back side of the plurality of back-contact battery cells 111. The first interconnection bar 112 and the second interconnection bar 113 are alternately arranged at the intermittent opening of the bus fixing adhesive layer 120 along the second direction for connecting adjacent back-contact battery cells 111. The first direction is perpendicular to the second direction.

[0037] It should be noted that the first interconnecting bar 112 and the second interconnecting bar 113 are both interconnecting bars on the back side of the back contact battery cell 111, wherein the first interconnecting bar 112 and the second interconnecting bar 113 are alternately distributed, and the one used for direct contact with the bus bar 150 is set as the first interconnecting bar 112, and the one used for isolation from the bus bar 150 is set as the second interconnecting bar 113. Their distribution and connection structure can refer to the existing back contact battery cell 111.

[0038] When actually preparing the long battery string 110, the following steps can be used: S11: providing a plurality of back-contact cells 111 arranged in series along a first direction.

[0039] Specifically, see Figure 3 First, the back contact cell 111 is prepared. The back contact cell 111 can be a half cell. Then, 2N back contact cells 111 are arranged in sequence along the first direction, where N is a natural number. For example, N is 6 here, that is, 12 back contact cells 111 are arranged in sequence along the first direction.

[0040] S12 : An insulating adhesive layer, a solder paste layer and an interconnect fixing adhesive layer 114 are sequentially printed on the back side of the back contact cell 111 .

[0041] See also Figure 4 Specifically, an insulating adhesive layer, a solder paste layer, and an interconnect fixing adhesive layer 114 can be printed sequentially on the back side of each back contact cell 111 according to the design position. The insulating adhesive layer can be a UV-curable adhesive or a thermosetting adhesive, cured by UV light or heat. The insulating adhesive layer can serve to insulate the oppositely charged electrodes. The solder paste layer can be cured by heat to complement the insulating adhesive layer and solder flux. The interconnect fixing adhesive layer 114 can be positioned according to the subsequent arrangement of the first interconnect bar 112 and the second interconnect bar 113, thereby securing the first interconnect bar 112 and the second interconnect bar 113.

[0042] S13: Printing and forming a busbar fixing adhesive layer 120 on the back side of the back contact battery cells 111 of the first, last and middle sheets.

[0043] See also Figure 5 The busbar fixing adhesive layer 120 is intermittently arranged along the second direction, and the interconnection fixing adhesive layer 114 is provided at the interruption of the busbar fixing adhesive layer 120. The busbar fixing adhesive layer 120 and the interconnection fixing adhesive layer 114 are spaced apart. Specifically, the busbar fixing adhesive layer 120 can be formed by printing according to the designed position through a printing process. The busbar fixing adhesive layer 120 is used to subsequently fix the busbar 150.

[0044] It should be noted that the interconnect-fixing adhesive layer 114 and the busbar-fixing adhesive layer 120 are made of different adhesive types and are not yet cured. For example, the interconnect-fixing adhesive layer 114 may be a thermally cured adhesive, while the busbar-fixing adhesive layer 120 may be a UV-curable adhesive. Alternatively, the interconnect-fixing adhesive layer 114 may be a UV-curable adhesive, while the busbar-fixing adhesive layer 120 may be a thermally cured adhesive. This embodiment uses the example of a case where the interconnect-fixing adhesive layer 114 is a thermally cured adhesive and the busbar-fixing adhesive layer 120 is a UV-curable adhesive.

[0045] S14 : Alternately arrange first interconnection bars 112 and second interconnection bars 113 along the second direction on the back side of the plurality of back-contact battery cells 111 .

[0046] See also Figure 6Specifically, the first interconnection bar 112 and the second interconnection bar 113 are laid at a predetermined position according to the designed position, in contact with the interconnection fixing adhesive layer 114, solder paste and insulating adhesive layer, and connected to the adjacent back contact battery cells 111, and then the interconnection fixing adhesive layer 114 is cured by heating, and the first interconnection bar 112 and the second interconnection bar 113 are fixedly bonded, so that multiple back contact battery cells 111 are connected in series through the first interconnection bar 112 and the second interconnection bar 113 to form a long battery string 110, wherein the first interconnection bar 112 and the second interconnection bar 113 are alternately arranged at the intermittent openings of the bus fixing adhesive layer 120.

[0047] It should be noted that the arrangement of the first interconnection bar 112 and the second interconnection bar 113 can be completed here according to the electrical design. For example, each long battery string 110 includes 2N back-contact battery cells 111, the back-contact battery cell 111 of the first piece and the back-contact battery cell 111 of the Nth piece are connected in series with each other, the back-contact battery cell 111 of the N+1th piece and the back-contact battery cell 111 of the tail piece are connected in series with each other, and the back-contact battery cell 111 of the Nth piece and the back-contact battery cell 111 of the N+1th piece are connected in parallel with each other.

[0048] It is worth noting that the long battery string 110 includes a first battery string 115 and a second battery string 116. When forming the long battery string 110, the first battery string 115 and the second battery string 116 can be formed separately, wherein the first battery string 115 and the second battery string 116 differ only in the arrangement of the first interconnection bars 112 and the second interconnection bars 113. For example, when laying the first interconnection bars 112 and the second interconnection bars 113, the first interconnection bars 112 and the second interconnection bars 113 can be laid alternately in a second direction along the back surface of a plurality of back-contact battery cells 111 arranged along the first direction according to a preset pattern to form the first battery string 115, that is, the first interconnection bars 112 are laid first in the first battery string 115. Furthermore, when laying the first interconnecting bars 112 and the second interconnecting bars 113, the second interconnecting bars 113 and the first interconnecting bars 112 can be laid alternately along the second direction on the back sides of the plurality of back-contact solar cells 111 arranged along the first direction according to a predetermined pattern to form a second solar cell string 116. Specifically, the second interconnecting bars 113 are laid before the second solar cell string 116. The first solar cell string 115 and the second solar cell string 116 can be designed to be symmetrical along the second direction.

[0049] In other preferred embodiments of the present invention, the following steps may be used to prepare the long battery string 110: S11: providing a plurality of back-contact solar cells 111 arranged in series along a first direction.

[0050] S12 : An insulating adhesive layer, a solder paste layer and an interconnect fixing adhesive layer 114 are sequentially printed on the back side of the back contact cell 111 .

[0051] An insulating adhesive layer, a solder paste layer, and an interconnect-fixing adhesive layer 114 can be printed sequentially on the back side of each back-contact cell 111 according to the design position. The insulating adhesive layer can be a UV-curable adhesive or a thermosetting adhesive, cured by UV light or heat. The insulating adhesive layer can insulate the oppositely charged electrodes. The solder paste layer can be cured by heat, complementing the insulating adhesive layer and solder flux. The interconnect-fixing adhesive layer 114 can be positioned according to the subsequent arrangement of the first interconnect bar 112 and the second interconnect bar 113, thereby securing the first interconnect bar 112 and the second interconnect bar 113.

[0052] S13 : Alternately arrange first interconnection bars 112 and second interconnection bars 113 along the second direction on the back side of the plurality of back contact cells 111 .

[0053] Specifically, the first interconnection bar 112 and the second interconnection bar 113 are laid at a predetermined position according to the designed position, in contact with the interconnection fixing adhesive layer 114, solder paste and insulating adhesive layer, and connected to adjacent back contact battery cells 111, and then the interconnection fixing adhesive layer 114 is cured by heating, and the first interconnection bar 112 and the second interconnection bar 113 are fixedly bonded, so that multiple back contact battery cells 111 are connected in series through the first interconnection bar 112 and the second interconnection bar 113 to form a long battery string 110, wherein the first interconnection bar 112 and the second interconnection bar 113 are alternately arranged at the intermittent openings of the bus fixing adhesive layer 120.

[0054] S14: forming a busbar fixing adhesive layer 120 on both sides of the first interconnection bar 112 and the second interconnection bar 113 on the back contact battery cells 111 of the first, last and middle cells.

[0055] The busbar fixing adhesive layer 120 is intermittently arranged along the second direction and is spaced apart from the first interconnection bars 112 and the second interconnection bars 113. Specifically, the busbar fixing adhesive layer 120 can be formed by a printing or dispensing process, and the first interconnection bars 112 and the second interconnection bars 113 are alternately arranged at the intermittent openings of the busbar fixing adhesive layer 120.

[0056] It should be noted that since the first interconnection bar 112 and the second interconnection bar 113 are set first, the bus fixing adhesive layer 120 can be better positioned when formed and ensure that the bus fixing adhesive layer 120 is spaced apart from the first interconnection bar 112 and the second interconnection bar 113.

[0057] After the first interconnection bars 112 , the second interconnection bars 113 and the busbar fixing adhesive layer 120 are prepared, the preparation of the long battery string 110 is completed, and steps S2 to S6 are continued.

[0058] S2: Laying out a plurality of long battery strings 110 on a substrate according to a preset pattern.

[0059] See also Figure 7 Specifically, a substrate with a front adhesive film layer can be provided first, and the substrate can be a front glass material. Then, the first battery string 115 and the second battery string 116 are colloidally laid on the substrate along the second direction, wherein the first battery string 115 and the second battery string 116 are symmetrical structures in the second direction.

[0060] S3 : Disposing insulating isolation strips 130 on the second interconnecting strips 113 at the intermittent openings of the busbar fixing adhesive layer 120 .

[0061] See also Figures 8 to 10 , wherein the insulating isolation strip 130 and the corresponding bus fixing adhesive layer 120 are arranged along the same straight line direction. After the first battery string 115 and the second battery string 116 are laid, the isolation area on the second interconnection strip 113 can be first delineated according to the bus fixing adhesive layer 120. The isolation area is located on the second interconnection strip 113 on the back contact battery cell 111 of the first piece, the tail piece and the middle piece. wherein the width of the isolation area along the first direction is greater than the width of the bus fixing adhesive layer 120; then a layer of insulating isolation strip 130 is laid on the top side and side wall of the second interconnection strip 113 in the isolation area, wherein the width of the insulating isolation strip 130 along the first direction is the same as the width of the isolation area, thereby ensuring that the width of the insulating isolation strip 130 is greater than the width of the bus fixing adhesive layer 120, thereby ensuring the electrical insulation effect. At the same time, the insulating isolation strip 130 is spaced apart from the bus fixing adhesive layer 120, which can prevent the insulating isolation strip 130 from affecting the bonding and fixing effect of the bus fixing adhesive layer 120. The thickness of the bus fixing adhesive layer 120 is greater than or equal to the sum of the thicknesses of the second interconnecting bar 113 and the insulating isolation bar 130. At this time, the bus fixing adhesive layer 120 is in an uncured state. Therefore, the relatively thicker setting can ensure that the bus fixing adhesive layer 120 is in contact with the subsequent bus bar 150, thereby ensuring the bonding and fixing effect.

[0062] It should be noted that the bus fixing adhesive layer 120 here can be located at the center line position of the corresponding back contact battery cell 111, so the isolation area on the second interconnection bar 113 is also located at the center line position of the corresponding back contact battery cell 111. The insulating isolation bar 130 can be prepared in advance. During actual positioning, the isolation area can be demarcated through a visual solution, and then the insulating isolation bar 130 can be placed on the second interconnection bar 113 in the isolation area through a robotic arm. Of course, the placement of the insulating isolation bar 130 can also be completed manually here. Among them, the insulating isolation bar 130 can be made of an insulating material, such as PET material, and the thickness of the insulating isolation bar 130 can be greater than or equal to 35μm.

[0063] In other preferred embodiments of the present invention, the insulating isolation strips 130 may also be formed by dispensing or printing processes, so that the thickness of the insulating isolation strips 130 is more uniform.

[0064] S4: The busbar 150 is arranged on the insulating spacer 130 and the busbar fixing adhesive layer 120 .

[0065] See also Figure 11 and Figure 12 Insulating strip 130 is used to electrically isolate bus bar 150 from second interconnect bar 113, and busbar fixing adhesive layer 120 is used to bond and secure bus bar 150, ensuring contact between bus bar 150 and first interconnect bar 112. The width of insulating strip 130 in the first direction can be greater than the width of bus bar 150, thereby ensuring its insulation and isolation, and effectively preventing contact between bus bar 150 and second interconnect bar 113.

[0066] When actually setting the busbar 150, the busbar 150 can first be aligned and laid on the corresponding busbar fixing adhesive layer 120 and insulating isolation bar 130 along the second direction. The busbar 150 can be positioned by visual inspection, for example, by the insulating isolation bar 130, the busbar fixing adhesive layer 120, or the additionally designed marking pad on the back of the back contact battery cell 111, or it can be aligned directly through the insulating isolation bar 130. The busbar 150 is used to connect adjacent long battery strings 110, and the busbars 150 on the back contact battery cells 111 of the first and last pieces and the busbar 150 on the back contact battery cell 111 of the middle piece are staggered along the second direction; then the busbar 150 is pressed down to make the busbar 150 contact the first interconnection bar 112; finally, the busbar fixing adhesive layer 120 is cured to complete the fixation of the busbar 150.

[0067] It should be noted that the busbar 150 can connect the first interconnecting bars 112 of the adjacent long battery strings 110 along the second direction, thereby realizing series connection. The busbar 150 is a conductive material, for example, a material with a core of copper and a coating of a lead-tin-bismuth alloy on the surface, and its thickness is generally 0.1-0.4 mm, for example, it can be any point value among 0.1 mm, 0.25 mm, 0.4 mm or a value between any two points. The width of the busbar 150 can be 4-10 mm, for example, it can be any point value among 4 mm, 7 mm, 10 mm or a value between any two points. When curing the busbar fixing adhesive layer 120, the curing means can be determined according to the adhesive layer material of the busbar fixing adhesive layer 120. For example, if the busbar fixing adhesive layer 120 is a UV adhesive layer, this can cause the fixing adhesive to undergo a curing reaction by irradiation with UV light, thereby bonding the busbar 150 to the first interconnecting bar 112.

[0068] It is worth noting that in this embodiment, the busbar fixing adhesive layer 120 is thicker than the first interconnecting bar 112. Therefore, during the pressing process, the busbar 150 first contacts the busbar fixing adhesive layer 120, and the busbar fixing adhesive layer 120 is further pressed downward and deformed until the busbar 150 contacts the first interconnecting bar 112. At this time, the busbar fixing adhesive layer 120 is fixed. Here, the busbar fixing adhesive layer 120 can be used to bond and fix the busbar 150 and make the busbar 150 contact the first interconnecting bar 112, facilitating subsequent welding and fixing.

[0069] In some embodiments, when pressing down the bus bar 150, a point-shaped pressing tool can be used, such as a pressing piece with multiple pressing heads. The multiple pressing heads press down the bus bar 150 corresponding to the positions of the multiple first interconnecting bars 112, which can cause the bus bar 150 to undergo a certain deformation and ensure that the bus bar 150 is in contact with the first interconnecting bar 112.

[0070] See also Figure 13 In other preferred embodiments of the present invention, a clearance groove 151 may be provided on the bottom side of the busbar 150, and the width of the clearance groove 151 in the second direction is adapted to the width of the insulating isolation bar 130. When the busbar 150 is laid on the bus fixing adhesive layer 120 and the insulating isolation bar 130, the clearance groove 151 on the bottom side of the busbar 150 can be aligned with the insulating isolation bar 130, and then the busbar 150 can be laid on the corresponding bus fixing adhesive layer 120 and the insulating isolation bar 130. Here, preferably, the busbar 150 can be pre-bent to form a clearance groove 151. The depth of the clearance groove 151 is adapted to the thickness of the insulating isolation bar 130. For example, the depth of the clearance groove 151 is slightly less than the thickness of the insulating isolation bar 130. Therefore, when the busbar 150 is pressed down, the busbar 150 can more easily contact the first interconnection bar 112, facilitating subsequent welding and fixation, and avoiding interference between the insulating isolation bar 130 and the busbar 150. The number of the clearance grooves 151 is adapted to the number of the insulating isolation bars 130, thereby fully achieving the clearance effect for the insulating isolation bars 130.

[0071] S5 : Laying the back sheet 160 on the long battery string 110 .

[0072] See also Figure 14 Specifically, after the busbars 150 are fixed, a backside adhesive film layer and a backsheet 160 can be sequentially laid on the long battery string 110 to form a battery assembly. The backside adhesive film layer can cover the backsides of the plurality of back-contact battery cells 111 and the busbars 150.

[0073] S6: Lamination welding of battery components.

[0074] Specifically, after the backsheet 160 is laid, the stacked battery assembly can be placed in a laminator for vacuuming and heating to a preset temperature, so that the first interconnecting bars 112 and the second interconnecting bars 113 are alloy-welded to the electrodes of the back-contact battery cell 111, and the bus bar 150 is alloy-welded to the first interconnecting bar 112. That is, the first interconnecting bars 112 and the second interconnecting bars 113 are welded and fixed to the back-contact battery cell 111, and the bus bar 150 is welded and fixed to the first interconnecting bar 112. Laminating and welding in a laminator can avoid local high-temperature welding. The vacuuming and heating in the laminator can melt the first interconnecting bars 112, the second interconnecting bars 113, the bus bar 150, the solder paste layer, and the electrodes of the back-contact battery cell 111 to form an alloy weld, completing the welding and fixing. Moreover, due to the overall low-temperature welding of the laminator, the negative effects of local high-temperature welding can be effectively avoided. At the same time, the adhesive film melts, bonding the glass, the back-contact battery cell 111, and the backsheet 160, thereby forming a laminate.

[0075] It should be noted that the preset temperature here is between 135°C and 155°C, for example, any one of 135°C, 145°C, and 155°C, or a value between any two of them, preferably 140°C to 150°C. Since the solder paste layer, first interconnection bar 112, second interconnection bar 113, and bus bar 150 are all low-temperature materials with melting temperatures between 140°C and 150°C, which is the same as the lamination temperature, low-temperature soldering technology can be implemented.

[0076] After lamination is completed, the frame and wiring frame can be installed according to the conventional component manufacturing process.

[0077] It is noteworthy that the method for preparing the back-contact battery assembly 100 provided in the embodiment of the present invention utilizes the busbar fixing adhesive layer 120 to secure the busbar 150, avoiding direct high-temperature welding. This effectively avoids the localized high-temperature welding process and the negative effects of localized high-temperature welding, such as cell warping and cracking. Furthermore, the busbar 150 can be hidden on the back of the battery, increasing battery size, improving assembly space utilization, and boosting assembly power.

[0078] See also Figure 11 、 Figure 15 and Figure 16On the other hand, an embodiment of the present invention further provides a back-contact battery assembly 100, which is prepared using the aforementioned method for preparing the back-contact battery assembly 100. The back-contact battery assembly 100 includes a substrate, an insulating spacer 130, a bus bar 150, a plurality of long battery strings 110, and a back plate 160. The substrate may be a front glass material. The plurality of long battery strings 110 are laid on the substrate. Each long battery string 110 includes a plurality of back-contact battery cells 111 arranged in sequence along a first direction. The back surfaces of the first, last, and middle back-contact battery cells 111 are formed with a busbar fixing adhesive layer 120 intermittently arranged along a second direction. The back surfaces of the plurality of back-contact battery cells 111 are also provided with first interconnecting bars 112 and second interconnecting bars 113 intermittently arranged along the first direction. The first interconnecting bars 112 and the second interconnecting bars 113 are alternately arranged at intermittent openings in the busbar fixing adhesive layer 120 along the second direction to connect adjacent back-contact battery cells 111. The first direction is perpendicular to the second direction. Insulating isolation bars 130 are arranged on the second interconnecting bars 113 at the intermittent openings of the busbar fixing adhesive layer 120. Insulating isolation bars 130 and the corresponding busbar fixing adhesive layer 120 are arranged along the same straight line. Busbars 150 are arranged on insulating isolation bars 130 and busbar fixing adhesive layer 120. Insulating isolation bars 130 are used to electrically isolate busbars 150 from the second interconnecting bars 113. Busbar fixing adhesive layer 120 is used to bond and fix busbars 150. Busbars 150 are welded to the first interconnecting bars 112. Backplane 160 is arranged on multiple long battery strings 110 and is located on the side of busbars 150 away from the substrate.

[0079] In some embodiments, multiple long battery strings 110 include a first battery string 115 and a second battery string 116. The first battery strings 115 and the second battery strings 116 are alternately arranged on the substrate along the second direction. The first interconnecting bars 112 and the second interconnecting bars 113 on the first battery string 115 and the first interconnecting bars 112 and the second interconnecting bars 113 on the second battery string 116 are symmetrical in the second direction. Specifically, the first interconnecting pattern formed by the first interconnecting bars 112 and the second interconnecting bars 113 on the first battery string 115 and the second interconnecting pattern formed by the first interconnecting bars 112 and the second interconnecting bars 113 on the second battery string 116 are symmetrical. The arrangement of the first battery strings 115 and the second battery strings 116 can better implement circuit design.

[0080] Furthermore, the bus bar 150 can realize the connection between the first battery string 115 and the second battery string 116, wherein the bus bar 150 on the back contact battery cell 111 of the first and last pieces and the bus bar 150 on the back contact battery cell 111 of the middle piece can be staggered along the second direction.

[0081] In some embodiments, each long battery string 110 includes 2N back-contact battery cells 111 arranged sequentially along a first direction, wherein the first back-contact battery cell 111 and the Nth back-contact battery cell 111 are connected in series, the N+1th back-contact battery cell 111 and the last back-contact battery cell 111 are connected in series, and the Nth back-contact battery cell 111 and the N+1th back-contact battery cell 111 are connected in parallel. Here, N is a natural number, such as 6, meaning that the 1st to 6th back-contact battery cells 111 are connected in series, the 7th to 12th back-contact battery cells 111 are connected in series, and the 6th and 7th back-contact battery cells 111 are connected in parallel (appearing to be connected in series). That is, in conventional technology, two independent sub-battery strings along the first direction are connected through the first interconnection bar 112 and the second interconnection bar 113, but in electrical design, the two battery strings form a parallel relationship (that is, the two sub-battery strings in the first direction in the same long battery string 110 are electrically connected in parallel). Through this electrical design, the number of battery strings in the embodiment of the present invention can be reduced by half, but the number of battery cells in the battery string can be doubled.

[0082] It should be noted that, compared to conventional technology, since the busbars 150 are no longer arranged at the head and tail ends of the battery string, the interconnection bars that originally protruded at the head and tail ends of the battery string are retracted to within the edge of the back contact battery cell 111 in the embodiment of the present invention. At the same time, the size of the back contact battery cell 111 in the first direction can be increased to fill the space where the original busbars 150 and the interconnection bars are retracted. Figure 1 , the width of the original busbar 150 in the first direction is L1, and the length of the original interconnection bar extending from the edge of the cell is L2. After adopting the back-side hiding solution of the embodiment of the present invention, the increased half-cell size d in the first direction satisfies the following formula: d=[L-(L1+L2)] / n; Wherein, L is the width of a conventional battery assembly in the first direction, and n is the number of battery cells in the first direction.

[0083] In some embodiments, in order to successfully hide the busbars 150 on the back side of the back-contact cell 111 while still having basic current extraction capabilities, they can be arranged in a certain pattern, and a busbar fixing adhesive layer 120 and an insulating isolation bar 130 are provided on the back side of the back-contact cell 111 of the first, last, and middle cells of each long battery string 110. The insulating isolation bar 130 serves to separate electrodes of opposite polarity and adhere to the interconnection bar of the electrodes of opposite polarity, that is, to the second interconnection bar 113. The material of the insulating isolation bar 130 includes, but is not limited to, PET material, and the width of the insulating isolation bar 130 in the first direction is greater than the width of the busbar 150, and the width in the second direction is greater than the width of the second interconnection bar 113. However, the insulating isolation bar 130 is spaced apart from the busbar fixing adhesive layer 120 to prevent it from affecting the bonding effect of the busbar fixing adhesive layer 120. The function of the bus fixing adhesive layer 120 is to fix the bus bar 150 to the back side of the back contact battery cell 111. In order to prevent the bus fixing adhesive layer 120 from affecting the overlap between the bus bar 150 and the first interconnecting bar 112, the bus fixing adhesive layer 120 should be located on both sides of the first interconnecting bar 112, but not contact the first interconnecting bar 112 and the insulating isolation bar 130.

[0084] In summary, the method for preparing a back-contact cell 111 and the back-contact cell 111 provided in an embodiment of the present invention first prepares a long cell string 110 consisting of a plurality of back-contact cell sheets 111 arranged in sequence along a first direction, wherein the back surfaces of the back-contact cell sheets 111 of the first, last, and middle cells are formed with a bus fixing adhesive layer 120 intermittently arranged along a second direction, and at the same time, a first interconnection bar 112 and a second interconnection bar 113 are provided on the back surfaces of the plurality of back-contact cell sheets 111, and the first interconnection bar 112 and the second interconnection bar 113 are provided at the intermittent openings of the bus fixing adhesive layer 120. Then, the plurality of long cell strings 110 are laid on a substrate according to a preset pattern. Then, an insulating isolation bar 130 is provided on the second interconnection bar 113 at the intermittent openings of the bus fixing adhesive layer 120. Then, a busbar 150 is arranged on the insulating isolation bar 130 and the busbar fixing adhesive layer 120. The insulating isolation bar 130 can electrically isolate the busbar 150 from the second interconnecting bar 113, while the busbar fixing adhesive layer 120 adheres and fixes the busbar 150, and makes the busbar 150 contact the first interconnecting bar 112. Finally, a back plate 160 is laid on the long battery string 110, and the formed battery assembly is laminated and welded to complete the welding and fixation between the first interconnecting bar 112, the second interconnecting bar 113 and the back contact battery cell 111, and between the busbar 150 and the first interconnecting bar 112. Compared with the prior art, the embodiment of the present invention can arrange the busbar 150 on the insulating isolation bar 130 and the busbar fixing adhesive layer 120 on the back of the back contact battery cell 111, so that the busbar 150 can be hidden on the back of the battery, which increases the battery size, improves the component space utilization, and improves the component power. Furthermore, by pre-preparing the busbar fixing adhesive layer 120, the busbar 150 can be directly bonded and fixed through the busbar fixing adhesive layer 120 during installation, avoiding high-temperature welding before lamination. This, in turn, avoids the high-temperature welding of the cell edges required to secure the busbar 150, as is commonly done in conventional techniques. Furthermore, the low-temperature lamination welding process used to weld the busbar 150 to the interconnecting bars effectively prevents cell warping, reduces the risk of hidden cracks or splinters, and improves cell quality and yield.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a back contact battery assembly, characterized in that: include: A long battery string (110) is prepared, wherein the long battery string (110) comprises a plurality of back contact battery sheets (111) arranged in sequence along a first direction, a bus fixing adhesive layer (120) intermittently arranged along a second direction is formed on the back sides of the first, last and middle back contact battery sheets (111), and a first interconnection bar (112) and a second interconnection bar (113) intermittently arranged along the first direction are provided on the back sides of the plurality of back contact battery sheets (111), the first interconnection bar (112) and the second interconnection bar (113) being alternately arranged at intervals along the second direction at the intermittent openings of the bus fixing adhesive layer (120) for connecting adjacent back contact battery sheets (111), and the first direction is perpendicular to the second direction; Laying a plurality of the long battery strings (110) on a substrate according to a preset pattern; An insulating isolation strip (130) is provided on the second interconnecting strip (113) at the intermittent opening of the busbar fixing adhesive layer (120), wherein the insulating isolation strip (130) and the corresponding busbar fixing adhesive layer (120) are arranged along the same straight line direction; A bus bar (150) is provided on the insulating isolation bar (130) and the bus fixing adhesive layer (120), wherein the insulating isolation bar (130) is used to electrically isolate the bus bar (150) from the second interconnection bar (113), and the bus fixing adhesive layer (120) is used to bond and fix the bus bar (150) so that the bus bar (150) contacts the first interconnection bar (112); Laying a back plate (160) on the long battery string (110) to form a battery assembly; The battery assembly is laminated and welded so that the first interconnection bar (112) and the second interconnection bar (113) are welded and fixed to the back contact battery sheet (111), and the bus bar (150) and the first interconnection bar (112) are welded and fixed.

2. The method for preparing a back contact battery assembly according to claim 1, wherein: The steps of preparing a long battery string (110) include: Providing a plurality of back-contact battery cells (111) arranged in series along a first direction; Printing a busbar fixing adhesive layer (120) on the back side of the back contact battery sheet (111) of the first sheet, the last sheet, and the middle sheet, wherein the busbar fixing adhesive layer (120) is intermittently arranged along the second direction; A first interconnection bar (112) and a second interconnection bar (113) are alternately arranged on the back side of the plurality of back-contact battery sheets (111) along a second direction, so that the plurality of back-contact battery sheets (111) are connected in series through the first interconnection bar (112) and the second interconnection bar (113) to form a long battery string (110), wherein the first interconnection bar (112) and the second interconnection bar (113) are alternately arranged at the intermittent openings of the busbar fixing adhesive layer (120).

3. The method for preparing a back contact battery assembly according to claim 2, characterized in that: Before the step of printing and forming a busbar fixing adhesive layer (120) on the back surface of the back contact battery sheets (111) of the first sheet, the last sheet and the middle sheet, the preparation method further comprises: An insulating adhesive layer, a solder paste layer, and an interconnection fixing adhesive layer (114) are sequentially printed on the back side of the back contact battery cell (111); The interconnection fixing adhesive layer (114) is used to fix the first interconnection bar (112) and the second interconnection bar (113), and the interconnection fixing adhesive layer (114) and the busbar fixing adhesive layer (120) are spaced apart.

4. The method for preparing a back contact battery assembly according to claim 3, wherein: The interconnection fixing adhesive layer (114) is a thermal fixing adhesive, and the confluence fixing adhesive layer (120) is a UV fixing adhesive; or, The interconnection fixing adhesive layer (114) is a UV fixing adhesive, and the confluence fixing adhesive layer (120) is a thermal fixing adhesive.

5. The method for preparing a back contact battery assembly according to claim 2, wherein: The step of arranging alternately distributed first interconnection bars (112) and second interconnection bars (113) on the back sides of a plurality of back contact battery sheets (111) comprises: Alternatingly laying first interconnection bars (112) and second interconnection bars (113) in sequence along a second direction on the back sides of a plurality of back contact battery sheets (111) arranged along a first direction according to a preset pattern to form a first battery string (115); Second interconnection bars (113) and first interconnection bars (112) are alternately laid in sequence along a second direction on the back sides of a plurality of back contact battery sheets (111) arranged along a first direction according to a preset pattern to form a second battery string (116).

6. The method for preparing a back contact battery assembly according to claim 5, characterized in that: The step of laying a plurality of the long battery strings (110) on a substrate according to a preset pattern comprises: Providing a substrate with a front adhesive film layer; Laying the first battery string (115) and the second battery string (116) alternately in sequence on a substrate along the second direction; The first battery string (115) and the second battery string (116) are symmetrical structures in the second direction.

7. The method for preparing a back contact battery assembly according to claim 1, wherein: The steps of preparing a long battery string (110) include: Providing a plurality of back-contact battery cells (111) arranged in series along a first direction; Alternating first interconnection bars (112) and second interconnection bars (113) along a second direction on the back surfaces of the plurality of back-contact battery sheets (111), so that the plurality of back-contact battery sheets (111) are connected in series via the first interconnection bars (112) and the second interconnection bars (113) to form a long battery string (110); A busbar fixing adhesive layer (120) is formed on both sides of the first interconnection bar (112) and the second interconnection bar (113) on the back contact battery sheet (111) of the first sheet, the tail sheet and the middle sheet, wherein the busbar fixing adhesive layer (120) is intermittently arranged along the second direction and is spaced apart from the first interconnection bar (112) and the second interconnection bar (113).

8. The method for preparing a back contact battery assembly according to claim 1, wherein: The step of providing an insulating isolation strip (130) on the second interconnection strip (113) at the intermittent opening of the busbar fixing adhesive layer (120) comprises: Delimiting an isolation area on the second interconnection strip (113) based on the busbar fixing adhesive layer (120), wherein the width of the isolation area along the first direction is greater than the width of the busbar fixing adhesive layer (120); A layer of insulating isolation strip (130) is laid on the top side and side wall of the second interconnection strip (113) in the isolation area, wherein the insulating isolation strip (130) is spaced apart from the bus fixing adhesive layer (120), and the thickness of the bus fixing adhesive layer (120) is greater than or equal to the sum of the thicknesses of the second interconnection strip (113) and the insulating isolation strip (130).

9. The method for preparing a back contact battery assembly according to claim 1, wherein: The step of arranging a bus bar (150) on the insulating isolation bar (130) and the bus fixing adhesive layer (120) comprises: Laying the busbars (150) on the corresponding busbar fixing adhesive layers (120) and the insulating isolation strips (130) in alignment along the second direction, wherein the busbars (150) are used to connect adjacent long battery strings (110), and the busbars (150) on the back contact battery sheets (111) of the first and last sheets and the busbars (150) on the back contact battery sheets (111) of the middle sheet are staggered along the second direction; Pressing down the bus bar (150) so that the bus bar (150) contacts the first interconnection bar (112); The confluence fixing adhesive layer (120) is cured.

10. The method for preparing a back contact battery assembly according to claim 9, characterized in that: The step of aligning and laying the busbar (150) on the corresponding busbar fixing adhesive layer (120) and the insulating isolation bar (130) along the second direction comprises: Aligning the clearance groove (151) on the bottom side of the bus bar (150) with the insulating isolation bar (130); The busbar (150) is laid on the corresponding busbar fixing adhesive layer (120) and the insulating isolation bar (130).

11. The method for preparing a back contact battery assembly according to claim 1, wherein: The step of laying a back plate (160) on the long battery string (110) comprises: Laying a back adhesive film layer and a back plate (160) in sequence on the long battery string (110); The backside adhesive film layer covers the backsides of the plurality of back-contact battery sheets (111) and the busbars (150).

12. The method for preparing a back contact battery assembly according to claim 1, wherein: The step of laminating and welding the battery assembly comprises: The battery assembly is placed in a laminator for vacuuming and heating to a preset temperature, so that the first interconnection bar (112) and the second interconnection bar (113) are alloy-welded with the electrodes of the back contact battery sheet (111), and the bus bar (150) and the first interconnection bar (112) are alloy-welded.

13. The method for preparing a back contact battery assembly according to claim 12, wherein: The preset temperature is between 135°C and 155°C.

14. A back-contact battery assembly, prepared by the method for preparing a back-contact battery assembly according to any one of claims 1 to 13, characterized in that: The back contact battery assembly comprises: substrate; A plurality of long battery strings (110) are laid on the substrate, each of the long battery strings (110) comprising a plurality of back contact battery sheets (111) arranged in sequence along a first direction, a busbar fixing adhesive layer (120) intermittently arranged along a second direction is formed on the back sides of the first, last and middle back contact battery sheets (111), and a first interconnection bar (112) and a second interconnection bar (113) intermittently arranged along the first direction are provided on the back sides of the plurality of back contact battery sheets (111), the first interconnection bar (112) and the second interconnection bar (113) being alternately arranged at intervals along the second direction at the intermittent openings of the busbar fixing adhesive layer (120) for connecting adjacent back contact battery sheets (111), the first direction being perpendicular to the second direction; an insulating isolation strip (130) provided on the second interconnection strip (113) at the intermittent opening of the busbar fixing adhesive layer (120), the insulating isolation strip (130) and the corresponding busbar fixing adhesive layer (120) being arranged along the same straight line direction; A bus bar (150) is provided on the insulating isolation bar (130) and the bus fixing adhesive layer (120), wherein the insulating isolation bar (130) is used to electrically isolate the bus bar (150) from the second interconnection bar (113), and the bus fixing adhesive layer (120) is used to bond and fix the bus bar (150), and the bus bar (150) is fixed to the first interconnection bar (112) by welding.

15. The back contact battery assembly according to claim 14, characterized in that The plurality of long battery strings (110) include a first battery string (115) and a second battery string (116), wherein the first battery string (115) and the second battery string (116) are alternately laid on the substrate in sequence along a second direction, and the first interconnection bar (112) and the second interconnection bar (113) on the first battery string (115) and the first interconnection bar (112) and the second interconnection bar (113) on the second battery string (116) are symmetrical structures in the second direction.

16. The back contact battery assembly according to claim 14, characterized in that Each of the long battery strings (110) comprises 2N back contact battery cells (111) arranged in sequence along a first direction, wherein the back contact battery cell (111) of the first battery cell and the back contact battery cell (111) of the Nth battery cell are connected in series, the back contact battery cell (111) of the N+1th battery cell and the back contact battery cell (111) of the last battery cell are connected in series, and the back contact battery cell (111) of the Nth battery cell and the back contact battery cell (111) of the N+1th battery cell are connected in parallel.

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