Method for manufacturing a back contact cell assembly and back contact cell assembly

Abstract

The application provides a preparation method of a back contact battery assembly and the back contact battery assembly, and relates to the technical field of solar cells. First, a long battery string is prepared, the back surface of a first piece, a tail piece and an intermediate piece is formed with a busbar fixing adhesive layer, and a first interconnection strip and a second interconnection strip are arranged. Then, a plurality of long battery strings are laid on a substrate. An insulating isolation strip is arranged on the second interconnection strip at a preset position. Then, a busbar is arranged on the insulating isolation strip and the busbar fixing adhesive layer. Finally, a back plate is laid, and laminated welding is performed. Compared with the prior art, the busbar can be hidden on the back surface of the battery, the size of the battery is increased, the space utilization of the assembly is improved, and the power of the assembly is improved. Meanwhile, the busbar fixing adhesive layer is prepared in advance, high-temperature welding on the edge of the battery piece during fixing of the busbar in the conventional technology is avoided, the warping of the battery piece can be effectively avoided, the risk of hidden cracks or broken pieces is reduced, and the quality and yield of the battery are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells, in particular, to a preparation method of a back contact cell assembly and a back contact cell assembly. BACKGROUND

[0002] A conventional back contact cell (BC cell) assembly is composed of a plurality of cell strings, and a busbar is connected with a cell string head-tail interconnection strip as a current lead component. In a conventional version design, the busbar needs to occupy a certain space (as shown in Figure 1 ), which limits the size of the cell and the power of the assembly.

[0003] In addition, in the preparation of the interconnection strip and the busbar, high-temperature welding is performed for fixation, that is, the electrical connection and fixation between the busbar and the interconnection strip are achieved through high-temperature welding. However, on the one hand, the high-temperature welding equipment is complex in structure, and on the other hand, high-temperature welding at the edge of the cell sheet is prone to cause the cell sheet to warp, which is prone to hidden cracks or cracks in subsequent processes, affecting the quality and yield of the cell. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of a back contact cell assembly and a back contact cell assembly, which can increase the size of the cell, improve the space utilization and power of the assembly, and avoid the warping of the cell sheet, thereby reducing the risk of hidden cracks or cracks and improving the quality and yield of the cell.

[0005] In a first aspect, the present application provides a preparation method of a back contact cell assembly, comprising:

[0006] Preparation of a long cell string, wherein the long cell string comprises a plurality of back contact cell sheets arranged in a first direction, and the back surface of the back contact cell sheet of the first sheet, the tail sheet and the middle sheet is formed with a busbar fixing adhesive layer arranged intermittently in a second direction, and the back surface of the plurality of back contact cell sheets is provided with a first interconnection strip and a second interconnection strip arranged intermittently in the first direction, and the first interconnection strip and the second interconnection strip are arranged alternately and spaced apart in the second direction at the intermittent opening of the busbar fixing adhesive layer, for connecting adjacent back contact cell sheets, and the first direction is perpendicular to the second direction;

[0007] Laying a plurality of long cell strings on a substrate according to a predetermined version;

[0008] Providing an insulating isolation strip on the second interconnection 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 in the same linear direction;

[0009] A busbar is arranged on the insulating isolation strip and the busbar fixing adhesive layer, wherein the insulating isolation strip is used to electrically isolate the busbar and the second interconnection strip, and the busbar fixing adhesive layer is used to adhesively fix the busbar and make the busbar contact the first interconnection strip;

[0010] A back plate is laid on the long battery string to form a battery assembly;

[0011] The battery assembly is laminated and welded to make the first interconnection strip and the second interconnection strip welded to the back contact battery piece, and the busbar and the first interconnection strip welded.

[0012] In an optional embodiment, the step of preparing a long battery string comprises:

[0013] A plurality of back contact battery pieces arranged in a string in a first direction are provided;

[0014] A busbar fixing adhesive layer is printed on the back of the back contact battery piece of the first piece, the last piece and the intermediate piece, wherein the busbar fixing adhesive layer is arranged intermittently in a second direction;

[0015] A first interconnection strip and a second interconnection strip are alternately arranged on the back of the plurality of back contact battery pieces in the second direction, so that the plurality of back contact battery pieces are connected in series by the first interconnection strip and the second interconnection strip to form a long battery string, wherein the first interconnection strip and the second interconnection strip are alternately arranged at the intermittent openings of the busbar fixing adhesive layer.

[0016] In an optional embodiment, before the step of printing a busbar fixing adhesive layer on the back of the back contact battery piece of the first piece, the last piece and the intermediate piece, the preparation method further comprises:

[0017] An insulating adhesive layer, a tin paste layer and an interconnection fixing adhesive layer are sequentially printed on the back of the back contact battery piece;

[0018] The interconnection fixing adhesive layer is used to fix the first interconnection strip and the second interconnection strip, and the interconnection fixing adhesive layer is arranged at intervals with the busbar fixing adhesive layer.

[0019] In an optional embodiment, the interconnection fixing adhesive layer is a thermal fixing adhesive, and the busbar fixing adhesive layer is a UV fixing adhesive; or the interconnection fixing adhesive layer is a UV fixing adhesive, and the busbar fixing adhesive layer is a thermal fixing adhesive.

[0020] In an optional embodiment, the step of arranging the first interconnection strip and the second interconnection strip alternately distributed on the back of the plurality of back contact battery pieces comprises:

[0021] The back surfaces of the plurality of back contact battery pieces arranged in the first direction are sequentially and alternately laid with the first interconnection strips and the second interconnection strips in the second direction according to a preset pattern to form the first battery string;

[0022] The back surfaces of the plurality of back contact battery pieces arranged in the first direction are sequentially and alternately laid with the second interconnection strips and the first interconnection strips in the second direction according to a preset pattern to form the second battery string.

[0023] In an optional embodiment, the step of laying the plurality of long battery strings on the substrate according to a preset layout includes:

[0024] A substrate with a front-side adhesive film is provided.

[0025] The first battery string and the second battery string are sequentially and alternately laid on the substrate in the second direction.

[0026] The first battery string and the second battery string are symmetrically arranged in the second direction.

[0027] In an optional embodiment, the step of preparing the long battery string includes:

[0028] A plurality of back contact battery pieces arranged in a string in the first direction are provided.

[0029] The back surfaces of the plurality of back contact battery pieces are alternately provided with the first interconnection strips and the second interconnection strips in the second direction, so that the plurality of back contact battery pieces are connected in series by the first interconnection strips and the second interconnection strips to form the long battery string.

[0030] The first interconnection strips and the second interconnection strips on the back contact battery pieces of the first piece, the tail piece and the intermediate piece are provided with busbar fixing adhesive layers on both sides, wherein the busbar fixing adhesive layers are discontinuously arranged in the second direction and spaced apart from the first interconnection strips and the second interconnection strips.

[0031] In an optional embodiment, the step of providing the insulating isolation strips on the second interconnection strips at the discontinuous openings of the busbar fixing adhesive layers includes:

[0032] The isolation region on the second interconnection strips is demarcated according to the busbar fixing adhesive layer, wherein the width of the isolation region in the first direction is greater than the width of the busbar fixing adhesive layer.

[0033] An insulating isolation strip is laid on the top side and the side wall of the second interconnection strip in the isolation region, wherein the insulating isolation strip is spaced apart from the busbar fixing adhesive layer, and the thickness of the busbar fixing adhesive layer is greater than or equal to the sum of the thicknesses of the second interconnection strip and the insulating isolation strip.

[0034] In an optional embodiment, the step of arranging the bus bar on the insulating isolation strip and the bus bar fixing adhesive layer comprises:

[0035] arranging the bus bar on the corresponding bus bar fixing adhesive layer and the insulating isolation strip in the second direction, wherein the bus bar is used for connecting adjacent long battery strings, and the bus bars on the back contact battery pieces of the first piece and the tail piece are arranged in the second direction staggered with the bus bars on the back contact battery pieces of the middle piece;

[0036] pressing the bus bar to make the bus bar contact the first interconnection strip;

[0037] solidifying the bus bar fixing adhesive layer.

[0038] In an optional embodiment, the step of arranging the bus bar on the insulating isolation strip and the bus bar fixing adhesive layer comprises:

[0039] aligning the accommodation groove on the bottom side of the bus bar with the insulating isolation strip;

[0040] arranging the bus bar on the corresponding bus bar fixing adhesive layer and the insulating isolation strip.

[0041] In an optional embodiment, the step of arranging the back plate on the long battery string comprises:

[0042] arranging a back adhesive film layer and a back plate on the long battery string in sequence;

[0043] wherein the back adhesive film layer covers the back surface of a plurality of back contact battery pieces and the bus bar.

[0044] In an optional embodiment, the step of laminating and welding the battery assembly comprises:

[0045] putting the battery assembly into a laminator to perform vacuum extraction and heating to a preset temperature, so that the first interconnection strip and the second interconnection strip form alloy welding with the electrodes of the back contact battery pieces, and the bus bar and the first interconnection strip form alloy welding.

[0046] In an optional embodiment, the preset temperature is between 135°C and 155°C.

[0047] In a second aspect, the present application provides a back contact battery assembly prepared by the preparation method of the back contact battery assembly according to any one of the preceding embodiments, wherein the back contact battery assembly comprises:

[0048] a substrate;

[0049] a plurality of long battery strings laid on the substrate, each of the long battery strings comprising a plurality of back contact battery pieces arranged in sequence along a first direction, the back surface of the back contact battery pieces of the first piece, the last piece and the intermediate pieces being formed with a busbar fixing adhesive layer intermittently arranged along a second direction, and the back surface of the plurality of back contact battery pieces being provided with a first interconnection strip and a second interconnection strip intermittently arranged along the first direction, the first interconnection strip and the second interconnection strip being alternately and spacedly arranged at the intermittent openings of the busbar fixing adhesive layer along the second direction, for connecting adjacent back contact battery pieces, the first direction being perpendicular to the second direction;

[0050] an insulating isolation strip arranged on the second interconnection strip at the intermittent openings of the busbar fixing adhesive layer, the insulating isolation strip being arranged along the same linear direction as the corresponding busbar fixing adhesive layer;

[0051] a busbar arranged on the insulating isolation strip and the busbar fixing adhesive layer, the insulating isolation strip being used for electrically isolating the busbar and the second interconnection strip, the busbar fixing adhesive layer being used for bonding and fixing the busbar, and the busbar being welded and fixed with the first interconnection strip.

[0052] In an optional embodiment, the plurality of long battery strings comprises a first battery string and a second battery string, the first battery string and the second battery string being laid in sequence and alternately along the second direction on the substrate, the first interconnection strip and the second interconnection strip on the first battery string and the first interconnection strip and the second interconnection strip on the second battery string being symmetrical structures in the second direction.

[0053] In an optional embodiment, each of the long battery strings comprises 2N back contact battery pieces arranged in sequence along the first direction, wherein the back contact battery piece of the first piece and the back contact battery piece of the Nth piece are connected in series with each other, the back contact battery piece of the N+1th piece and the back contact battery piece of the last piece are connected in series with each other, and the back contact battery piece of the Nth piece and the back contact battery piece of the N+1th piece are connected in parallel with each other.

[0054] The beneficial effects of the embodiments of the present application include:

[0055] The present invention provides a method for preparing a back-contact battery cell and a back-contact battery cell. The method first prepares a long battery string composed of multiple back-contact battery cells arranged sequentially along a first direction. The back sides of the first, last, and middle back-contact battery cells have intermittently arranged busbar fixing adhesive layers along a second direction. Simultaneously, the back sides of the multiple back-contact battery cells are provided with first and second interconnecting strips, which are located at the intermittent openings of the busbar fixing adhesive layers. Then, the multiple long battery strings are laid on a substrate according to a preset pattern. Insulating strips are then provided on the second interconnecting strips at the intermittent openings of the busbar fixing adhesive layers. Next, busbars are provided on the insulating strips and the busbar fixing adhesive layers. The insulating strips electrically isolate the busbars and the second interconnecting strips, while the busbar fixing adhesive layer bonds and fixes the busbars, ensuring contact between the busbars and the first interconnecting strips. Finally, a backplate is laid on the long battery string, and the formed battery assembly is laminated and welded to complete the welding and fixing between the first and second interconnecting strips and the back-contact battery cells, and between the busbars and the first interconnecting strips.

[0056] Compared to existing technologies, this invention allows the busbar to be positioned on the insulating separator and busbar fixing adhesive layer on the back of the back-contacting solar cell. This conceals the busbar on the back of the cell, increasing cell size, improving module space utilization, and boosting module power. Furthermore, by pre-preparing the busbar fixing adhesive layer, the busbar can be directly bonded and fixed using this layer, avoiding high-temperature welding before lamination. This eliminates the need for high-temperature welding of the cell edges during busbar fixing, a common practice in conventional technologies. Moreover, the use of a low-temperature lamination welding process to connect the busbar to the interconnecting strip effectively prevents cell warping, reduces the risk of microcracks or cell breakage, and improves cell quality and yield. Attached Figure Description

[0057] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a schematic diagram of the distribution structure of a back-contact battery assembly in the prior art;

[0059] Figure 2 A flowchart illustrating the steps of a method for preparing a back contact battery assembly according to an embodiment of the present invention;

[0060] Figures 3 to 6 for Figure 2 A schematic diagram of the process flow for step S1;

[0061] Figure 7 For Figure 2 Process flowchart of step S2 in the embodiment;

[0062] Figure 8 For Figure 2 Process flowchart of step S3 in the embodiment;

[0063] Figure 9 For Figure 8 Local enlarged schematic view of IX in the embodiment;

[0064] Figure 10 For Figure 8 Local sectional view of A-A in the embodiment;

[0065] Figure 11 For Figure 2 Process flowchart of step S4 in the embodiment;

[0066] Figure 12 For Figure 11 Local sectional view of B-B in the embodiment;

[0067] Figure 13 For Figure 11 Local sectional view of B-B in other preferred embodiments;

[0068] Figure 14 For Figure 2 Process flowchart of step S5 in the embodiment;

[0069] Figure 15 Exploded schematic view of the back contact battery assembly provided by the embodiment;

[0070] Figure 16 Local structural sectional view of the back contact battery assembly provided by the embodiment.

[0071] Figure legend: 100-back contact battery assembly; 110-long battery string; 111-back contact battery piece; 112-first interconnection strip; 113-second interconnection strip; 114-interconnection fixed adhesive layer; 115-first battery string; 116-second battery string; 120-converging fixed adhesive layer; 130-insulating isolation strip; 140-substrate; 150-converging strip; 151-give-way recess; 160-back plate. DETAILED DESCRIPTION

[0072] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0073] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0074] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0075] In the description of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0076] In addition, if the terms "first", "second" and the like appear, they are only used for differentiation description, and cannot be understood as indicating or implying relative importance.

[0077] As disclosed in the background, for the back contact cell in the prior art, it is usually designed as a half-assembly design, the busbar is connected with the cell head and tail interconnection strip as the current lead-out part, in the conventional version design, the busbar 150 needs to occupy a certain space (as shown in Figure 1 The size of the battery is limited, and the power of the assembly is limited.

[0078] Further, there is a scheme of arranging the busbar on the back surface of the back contact cell, however, in this scheme, high-temperature welding is performed when preparing the interconnection strip and the busbar to ensure that the busbar and the interconnection strip are welded and fixed, and such high-temperature welding process will cause the local thermal stress of the cell to increase, and easily cause the cell to warp, and hidden cracks or cracked pieces are easily generated in the subsequent process, which affects the quality and yield of the battery.

[0079] To solve the above problems, the embodiment of the present application provides a preparation method of a back contact battery assembly and the back contact battery assembly, and it should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0080] Referring to Figure 2 The embodiment of the present application provides a preparation method of a back contact battery assembly 100, which is used for preparing the back contact battery assembly 100. The back contact battery assembly 100 prepared by the method can increase the size of the battery, improve the space utilization and power of the assembly, avoid the warping of the battery piece, reduce the risk of hidden cracks or broken pieces, and improve the quality and yield of the battery.

[0081] The preparation method of the back contact battery assembly 100 provided by the embodiment of the present application comprises the following steps:

[0082] S1: preparing a long battery string 110.

[0083] Referring to Figures 3 to 6 The long battery string 110 comprises a plurality of back contact battery pieces 111 arranged in the first direction. The back surface of the back contact battery piece 111 of the first piece, the tail piece and the middle piece is formed with a busbar fixing adhesive layer 120 arranged intermittently in the second direction. The back surface of the plurality of back contact battery pieces 111 is provided with a first interconnection strip 112 and a second interconnection strip 113 arranged intermittently in the first direction. The first interconnection strip 112 and the second interconnection strip 113 are arranged alternately and spaced apart in the second direction at the intermittent opening of the busbar fixing adhesive layer 120, and are used for connecting adjacent back contact battery pieces 111. The first direction is perpendicular to the second direction.

[0084] It should be noted that the first interconnection strip 112 and the second interconnection strip 113 are both interconnection strips on the back surface of the back contact battery piece 111. The first interconnection strip 112 and the second interconnection strip 113 are alternately distributed, and the first interconnection strip 112 is set for direct contact with the busbar 150, and the second interconnection strip 113 is set for isolation from the busbar 150. The distribution and connection structure can refer to the existing back contact battery piece 111.

[0085] In actual preparation of the long battery string 110, the following steps can be used to complete:

[0086] S11: providing a plurality of back contact battery pieces 111 arranged in a string in the first direction.

[0087] Specifically, referring to Figure 3First, the preparation of the back contact cell piece 111 is completed, which can be a half cell piece, and then 2N back contact cell pieces 111 are arranged in the first direction in sequence with intervals, where N is a natural number, for example, N is 6 here, that is, 12 back contact cell pieces 111 are arranged in the first direction in sequence.

[0088] S12: The insulating adhesive layer, the tin paste layer and the interconnection fixing adhesive layer 114 are printed in sequence on the back of the back contact cell piece 111.

[0089] Referring to Figure 4 Specifically, the insulating adhesive layer, the tin paste layer and the interconnection fixing adhesive layer 114 can be printed in sequence on the back of each back contact cell piece 111 according to the design position, where the insulating adhesive layer can be UV curing adhesive or heat curing adhesive, which is cured by UV light or heating, and the insulating adhesive layer can play the role of insulating the heterogeneous electrode. The tin paste layer can be cured by heating, which plays the role of compensating the insulating adhesive layer and the flux. The interconnection fixing adhesive layer 114 can be set according to the arrangement position of the subsequent first interconnection strip 112 and the second interconnection strip 113, and can realize the fixation of the first interconnection strip 112 and the second interconnection strip 113.

[0090] S13: The busbar fixing adhesive layer 120 is printed on the back of the back contact cell piece 111 of the first piece, the tail piece and the middle piece.

[0091] Referring to Figure 5 The busbar fixing adhesive layer 120 is discontinuously arranged along the second direction, and the interconnection fixing adhesive layer 114 is arranged at the discontinuous opening of the busbar fixing adhesive layer 120, and the busbar fixing adhesive layer 120 and the interconnection fixing adhesive layer 114 are arranged with intervals. Specifically, the busbar fixing adhesive layer 120 can be printed to form by printing process according to the design position, which is used for subsequent fixation of the busbar 150.

[0092] It should be noted that the adhesive layers of the interconnection fixing adhesive layer 114 and the busbar fixing adhesive layer 120 are different, and are not cured at present. For example, the interconnection fixing adhesive layer 114 is heat curing adhesive, and the busbar fixing adhesive layer 120 is UV curing adhesive; or the interconnection fixing adhesive layer 114 is UV curing adhesive, and the busbar fixing adhesive layer 120 is heat curing adhesive. In this embodiment, the interconnection fixing adhesive layer 114 is heat curing adhesive, and the busbar fixing adhesive layer 120 is UV curing adhesive.

[0093] S14: The first interconnection strip 112 and the second interconnection strip 113 are alternately arranged along the second direction on the back of the plurality of back contact cell pieces 111.

[0094] Referring to Figure 6Specifically, the first interconnection strip 112 and the second interconnection strip 113 are laid at the designed positions, contacted with the interconnection fixing adhesive layer 114, the tin paste and the insulating adhesive layer, and connected with the adjacent back contact battery pieces 111, and then the interconnection fixing adhesive layer 114 is cured by heating to fix and bond the first interconnection strip 112 and the second interconnection strip 113, so that the plurality of back contact battery pieces 111 are connected in series by the first interconnection strip 112 and the second interconnection strip 113 to form the long battery string 110, wherein the first interconnection strip 112 and the second interconnection strip 113 are alternately arranged at the intermittent openings of the busbar fixing adhesive layer 120.

[0095] It should be noted that the arrangement of the first interconnection strip 112 and the second interconnection strip 113 can be completed according to the electrical design, for example, each long battery string 110 includes 2N back contact battery pieces 111, the first back contact battery piece 111 and the Nth back contact battery piece 111 are connected in series with each other, the N+1th back contact battery piece 111 and the last back contact battery piece 111 are connected in series with each other, and the Nth back contact battery piece 111 and the N+1th back contact battery piece 111 are connected in parallel with each other.

[0096] It should be noted that the long battery string 110 includes the first battery string 115 and the second battery string 116, and the first battery string 115 and the second battery string 116 can be formed respectively when the long battery string 110 is formed, wherein the first battery string 115 and the second battery string 116 only differ in the arrangement of the first interconnection strip 112 and the second interconnection strip 113. For example, when the first interconnection strip 112 and the second interconnection strip 113 are laid, the first interconnection strip 112 and the second interconnection strip 113 can be alternately laid in the second direction on the back surface of the plurality of back contact battery pieces 111 arranged in the first direction according to the preset pattern to form the first battery string 115, that is, the first battery string 115 lays the first interconnection strip 112 first. In addition, when the first interconnection strip 112 and the second interconnection strip 113 are laid, the second interconnection strip 113 and the first interconnection strip 112 can be alternately laid in the second direction on the back surface of the plurality of back contact battery pieces 111 arranged in the first direction according to the preset pattern to form the second battery string 116, that is, the second battery string 116 lays the second interconnection strip 113 first. Wherein, the first battery string 115 and the second battery string 116 can be designed symmetrically in the second direction.

[0097] In other preferred embodiments of the present application, the following steps can also be used to complete the actual preparation of the long battery string 110:

[0098] S11: providing a plurality of back contact battery pieces 111 arranged in series in the first direction.

[0099] S12: printing an insulating adhesive layer, a tin paste layer and an interconnection fixing adhesive layer 114 in sequence on the back of the back contact cell 111.

[0100] The insulating adhesive layer can be UV curing adhesive or heat curing adhesive, which can be cured by UV light or heating, and can play the role of insulating the heterogeneous electrode. The tin paste layer can be cured by heating, which can compensate for the insulating adhesive layer and flux. The interconnection fixing adhesive layer 114 can be arranged according to the arrangement position of the subsequent first interconnection strip 112 and the second interconnection strip 113, and can realize the fixation of the first interconnection strip 112 and the second interconnection strip 113.

[0101] S13: alternately arranging the first interconnection strip 112 and the second interconnection strip 113 along the second direction on the back of the plurality of back contact cells 111.

[0102] Specifically, the first interconnection strip 112 and the second interconnection strip 113 are laid in the designated position, in contact with the interconnection fixing adhesive layer 114, the tin paste and the insulating adhesive layer, and connected to the adjacent back contact cells 111, and then the interconnection fixing adhesive layer 114 is cured by heating to fix and bond the first interconnection strip 112 and the second interconnection strip 113, so that the plurality of back contact cells 111 are connected in series by the first interconnection strip 112 and the second interconnection strip 113 to form the long battery string 110, wherein the first interconnection strip 112 and the second interconnection strip 113 are alternately arranged at the intermittent openings of the busbar fixing adhesive layer 120.

[0103] S14: forming a busbar fixing adhesive layer 120 on both sides of the first interconnection strip 112 and the second interconnection strip 113 on the back contact cells 111 of the first piece, the tail piece and the middle piece.

[0104] The busbar fixing adhesive layer 120 is intermittently arranged along the second direction and spaced apart from the first interconnection strip 112 and the second interconnection strip 113. Specifically, the busbar fixing adhesive layer 120 can be formed by printing or dispensing process, and the first interconnection strip 112 and the second interconnection strip 113 are alternately arranged at the intermittent openings of the busbar fixing adhesive layer 120.

[0105] It should be noted that since the first interconnection strip 112 and the second interconnection strip 113 are completed first, the busbar fixing adhesive layer 120 can be better positioned when formed, and the busbar fixing adhesive layer 120 is spaced apart from the first interconnection strip 112 and the second interconnection strip 113.

[0106] After the preparation of the first interconnection strip 112, the second interconnection strip 113 and the busbar fixing adhesive layer 120 is completed, the preparation of the long battery string 110 is completed, and steps S2 to S6 are continued.

[0107] S2: lay a plurality of long battery strings 110 on the substrate according to a preset version.

[0108] Referring to Figure 7 Specifically, a substrate with a front-side adhesive film layer can be provided first, and the substrate can be a front-side glass material. Then, the first battery string 115 and the second battery string 116 can be laid on the substrate in the second direction by adhesive, where the first battery string 115 and the second battery string 116 are symmetrical structures in the second direction.

[0109] S3: disposing an insulating isolation strip 130 on the second interconnection strip 113 at the discontinuous opening of the busbar fixing adhesive layer 120.

[0110] Referring to Figures 8 to 10 Wherein, the insulating isolation strip 130 and the corresponding busbar fixing adhesive layer 120 are arranged along the same linear direction. After the laying of the first battery string 115 and the second battery string 116 is completed, the isolation area on the second interconnection strip 113 on the back contact cell piece 111 of the first piece, the tail piece and the middle piece can be first demarcated according to 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; then a layer of insulating isolation strip 130 is laid on the top side and the 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, so as to ensure that the width of the insulating isolation strip 130 is greater than the width of the busbar fixing adhesive layer 120, and the electrical insulation effect is ensured. At the same time, the insulating isolation strip 130 is spaced apart from the busbar fixing adhesive layer 120, which can avoid the influence of the insulating isolation strip 130 on the bonding and fixing effect of the busbar fixing adhesive layer 120. And the thickness of the busbar 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, at this time the busbar fixing adhesive layer 120 is in an uncured state, so the relatively thicker setting can ensure that the busbar fixing adhesive layer 120 contacts the subsequent busbar 150, and the bonding and fixing effect is ensured.

[0111] It should be noted that the busbar fixing adhesive layer 120 can be located at the center line position of the corresponding back contact cell piece 111, so the isolation area on the second interconnection strip 113 is also located at the center line position of the corresponding back contact cell piece 111. The insulating isolation strip 130 can be prepared in advance, and when positioning, the demarcation of the isolation area can be realized by a visual scheme, and then the insulating isolation strip 130 is placed on the second interconnection strip 113 in the isolation area by a mechanical arm. Of course, the placement of the insulating isolation strip 130 can also be completed by manual method. Wherein, the insulating isolation strip 130 can be made of insulating material, such as PET material, and the thickness of the insulating isolation strip 130 can be greater than or equal to 35μm.

[0112] In other preferable embodiments of the present application, the insulating isolation strips 130 can also be formed by a dispensing or printing process, so that the thickness of the insulating isolation strips 130 is more uniform.

[0113] S4: disposing the bus bars 150 on the insulating isolation strips 130 and the bus bar fixing adhesive layers 120.

[0114] Referring to Figure 11 and Figure 12 , the insulating isolation strips 130 are used to electrically isolate the bus bars 150 and the second interconnection strips 113, and the bus bar fixing adhesive layers 120 are used to bond and fix the bus bars 150 and make the bus bars 150 contact the first interconnection strips 112. The width of the insulating isolation strips 130 in the first direction can be greater than the width of the bus bars 150, so as to ensure the insulating isolation effect and effectively avoid the contact between the bus bars 150 and the second interconnection strips 113.

[0115] In actual arrangement of the bus bars 150, the bus bars 150 can be first laid in the second direction on the corresponding bus bar fixing adhesive layers 120 and insulating isolation strips 130. The bus bars 150 can be positioned by visual detection, for example, by the insulating isolation strips 130, the bus bar fixing adhesive layers 120 or the mark pads designed on the back surface of the back contact battery pieces 111, or directly by the insulating isolation strips 130. The bus bars 150 are used to connect the adjacent long battery strings 110, and the bus bars 150 on the back contact battery pieces 111 of the head and tail pieces are arranged in a staggered manner in the second direction with the bus bars 150 on the back contact battery pieces 111 of the middle pieces. Then, the bus bars 150 are pressed to make the bus bars 150 contact the first interconnection strips 112. Finally, the bus bar fixing adhesive layers 120 are solidified to complete the fixing of the bus bars 150.

[0116] It should be noted that the bus bars 150 can connect the first interconnection strips 112 of the adjacent long battery strings 110 in the second direction, so as to realize series connection. The bus bars 150 are made of conductive material, for example, a material with a core of copper and a surface of lead-tin-bismuth alloy coating, and the thickness thereof is usually 0.1-0.4 mm, for example, any one of 0.1 mm, 0.25 mm and 0.4 mm or a value between any two of them. The width of the bus bars 150 can be 4-10 mm, for example, any one of 4 mm, 7 mm and 10 mm or a value between any two of them. The solidification means of the bus bar fixing adhesive layers 120 can be determined according to the adhesive material of the bus bar fixing adhesive layers 120. For example, when the bus bar fixing adhesive layers 120 are UV adhesive layers, the bus bars 150 can be bonded with the first interconnection strips 112 by irradiating the fixing adhesive with UV light to make the fixing adhesive solidify.

[0117] It is worth noting that the thickness of the busbar fixing adhesive layer 120 in this embodiment is relatively larger than the thickness of the first interconnection strip 112, so in the process of pressing down, the busbar 150 first contacts the busbar fixing adhesive layer 120, and the busbar fixing adhesive layer 120 is continuously pressed down and deformed until the busbar 150 contacts the first interconnection strip 112, and then the busbar fixing adhesive layer 120 is fixed. At this point, the busbar 150 can be bonded and fixed by the busbar fixing adhesive layer 120, and the busbar 150 is in contact with the first interconnection strip 112, which facilitates subsequent welding and fixing.

[0118] In some embodiments, when the busbar 150 is pressed down, a point-like pressing tool can be used, such as a pressing member with multiple pressing heads corresponding to the positions of the multiple first interconnection strips 112 to press down the busbar 150, which can cause the busbar 150 to deform to a certain extent and ensure that the busbar 150 is in contact with the first interconnection strip 112.

[0119] Referring to Figure 13 In other preferred embodiments of the present application, the bottom side of the busbar 150 can be provided with a recess 151, and the width of the recess 151 in the second direction is adapted to the width of the insulating isolation strip 130. When the busbar 150 is laid on the busbar fixing adhesive layer 120 and the insulating isolation strip 130, the recess 151 on the bottom side of the busbar 150 can be aligned with the insulating isolation strip 130, and then the busbar 150 is laid on the corresponding busbar fixing adhesive layer 120 and insulating isolation strip 130. Preferably, the recess 151 can be formed by pre-bending the busbar 150, and the depth of the recess 151 is adapted to the thickness of the insulating isolation strip 130, for example, the depth of the recess 151 is slightly smaller than the thickness of the insulating isolation strip 130, so that in the process of pressing down the busbar 150, the busbar 150 can more easily contact the first interconnection strip 112, facilitating subsequent welding and fixing, and avoiding interference of the insulating isolation strip 130 with the busbar 150. The number of recesses 151 is adapted to the number of insulating isolation strips 130, so as to fully realize the recessing effect of the insulating isolation strips 130.

[0120] S5: Laying a back plate 160 on the long battery string 110.

[0121] Referring to Figure 14 Specifically, after the fixing of the busbar 150 is completed, a back adhesive film layer and a back plate 160 can be laid on the long battery string 110 in sequence, thereby forming a battery assembly. The back adhesive film layer can cover the back surfaces of the multiple back contact battery pieces 111 and the busbar 150.

[0122] S6: Laminating and welding the battery assembly.

[0123] Specifically, after the back plate 160 is laid, the completed battery assembly can be put into a laminator to be vacuumized and heated to a preset temperature, so that the first interconnection strip 112 and the second interconnection strip 113 are both alloy welded with the electrodes of the back contact battery piece 111, and the bus bar 150 and the first interconnection strip 112 are alloy welded, that is, the first interconnection strip 112 and the second interconnection strip 113 are welded and fixed with the back contact battery piece 111, and the bus bar 150 and the first interconnection strip 112 are welded and fixed. Through the laminating welding of the laminator, local high-temperature welding can be avoided, and vacuumization and heating and other actions in the laminator can make the first interconnection strip 112, the second interconnection strip 113, the bus bar 150, the tin paste layer and the electrodes of the back contact battery piece 111 melt with each other to form alloy welding, complete welding and fixation, and effectively avoid the negative effects of local high-temperature welding due to the low-temperature welding of the laminator as a whole. At the same time, the adhesive film melts to bond the glass, the back contact battery piece 111 and the back plate 160, thereby forming a laminated part.

[0124] It should be noted that the preset temperature is between 135℃ and 155℃, for example, it can be any one of 135℃, 145℃, 155℃ or a value between any two points, and preferably it can be 140℃-150℃. Since the tin paste layer, the first interconnection strip 112, the second interconnection strip 113 and the bus bar 150 are all low-temperature materials with a melting temperature of 140℃-150℃, which is the same as the laminating temperature, so that low-temperature welding technology can be realized.

[0125] After laminating is completed, the installation of the frame and the wiring frame can be performed according to the conventional assembly process.

[0126] It should be noted that the preparation method of the back contact battery assembly 100 provided by the embodiment of the application uses the bus bar fixing adhesive layer 120 to fix the bus bar 150, avoiding the direct high-temperature welding fixation scheme, so that local high-temperature welding process can be effectively avoided, and the negative effects such as battery piece warping and hidden cracking caused by local high-temperature welding can be avoided. At the same time, the bus bar 150 can be hidden at the back of the battery, increasing the size of the battery, improving the space utilization of the assembly, and improving the power of the assembly.

[0127] Referring to Figure 11 , Figure 15 and Figure 16In another aspect, the embodiments of the present application also provide a back contact battery assembly 100 prepared by the above-mentioned method for preparing a back contact battery assembly 100. The back contact battery assembly 100 comprises a substrate, an insulating isolation strip 130, a busbar 150, a plurality of long battery strings 110 and a back plate 160. The substrate can be a front glass material. The plurality of long battery strings 110 are laid on the substrate. Each long battery string 110 comprises a plurality of back contact battery pieces 111 arranged in a first direction. The back surface of the first piece, the tail piece and the middle piece of the back contact battery piece 111 is formed with a busbar fixing adhesive layer 120 arranged intermittently in a second direction. The back surface of the plurality of back contact battery pieces 111 is provided with a first interconnection strip 112 and a second interconnection strip 113 arranged intermittently in the first direction. The first interconnection strip 112 and the second interconnection strip 113 are arranged alternately and spaced apart in the second direction at the intermittent opening of the busbar fixing adhesive layer 120, for connecting adjacent back contact battery pieces 111. The first direction is perpendicular to the second direction. The insulating isolation strip 130 is arranged on the second interconnection strip 113 at the intermittent opening of the busbar fixing adhesive layer 120. The insulating isolation strip 130 is arranged in the same linear direction as the corresponding busbar fixing adhesive layer 120. The busbar 150 is arranged on the insulating isolation strip 130 and the busbar fixing adhesive layer 120. The insulating isolation strip 130 is used to electrically isolate the busbar 150 and the second interconnection strip 113. The busbar fixing adhesive layer 120 is used to bond and fix the busbar 150. The busbar 150 is welded and fixed with the first interconnection strip 112. The back plate 160 is arranged on the plurality of long battery strings 110 and located on the side of the busbar 150 away from the substrate.

[0128] In some embodiments, the plurality of long battery strings 110 comprises a first battery string 115 and a second battery string 116. The first battery string 115 and the second battery string 116 are laid alternately in the second direction on the substrate. The first interconnection strip 112 and the second interconnection strip 113 on the first battery string 115 and the first interconnection strip 112 and the second interconnection strip 113 on the second battery string 116 are in a symmetrical structure in the second direction. Specifically, the first interconnection pattern composed of the first interconnection strip 112 and the second interconnection strip 113 on the first battery string 115 and the second interconnection pattern composed of the first interconnection strip 112 and the second interconnection strip 113 on the second battery string 116 are in a symmetrical structure. Through the arrangement of the first battery string 115 and the second battery string 116, the circuit design can be better realized.

[0129] Further, the busbar 150 can realize the connection between the first battery string 115 and the second battery string 116. The busbar 150 on the back contact battery piece 111 of the first piece and the tail piece and the busbar 150 on the back contact battery piece 111 of the middle piece can be arranged in a staggered manner in the second direction.

[0130] In some embodiments, each long battery string 110 includes 2N back contact battery pieces 111 arranged in sequence along the first direction, wherein the back contact battery piece 111 of the first piece and the back contact battery piece 111 of the Nth piece are connected in series with each other, the back contact battery piece 111 of the N+1th piece and the back contact battery piece 111 of the last piece are connected in series with each other, and the back contact battery piece 111 of the Nth piece and the back contact battery piece 111 of the N+1th piece are connected in parallel with each other. Here, N is a natural number, for example, can be 6, that is, the first piece to the sixth piece of back contact battery piece 111 is in series structure, the seventh piece to the twelfth piece of back contact battery piece 111 is in series structure, and the sixth piece and the seventh piece of back contact battery piece 111 are in parallel structure (apparently in series). That is, two sub-battery strings that should be independent along the first direction in the conventional technology are connected by the first interconnection strip 112 and the second interconnection strip 113, but in the 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 application can be reduced by half, but the number of battery pieces in the battery string is doubled.

[0131] It should be noted that, compared with the conventional technology, since the bus bar 150 is no longer arranged at the head and tail of the battery string, the original interconnection strip protruding at the head and tail of the battery string is retracted into the edge of the back contact battery piece 111 in the embodiment of the application, and the size of the back contact battery piece 111 in the first direction can be increased to fill the space of the original bus bar 150 and the retracted interconnection strip. As shown in FIG. 1, the width of the original bus bar 150 in the first direction is L1, and the length of the original interconnection strip protruding from the edge of the battery piece is L2. After adopting the back hiding scheme of the embodiment of the application, the increased half battery size d in the first direction satisfies the following formula: Figure 1

[0132] d=[L-(L1+L2)] / n;

[0133] Wherein, L is the width of the first direction in the conventional battery assembly, and n is the number of battery pieces in the first direction.

[0134] ​In some embodiments, in order to make the busbar 150 successfully hidden in the back of the back contact battery piece 111, and still have the basic current lead-out ability, therefore can be arranged according to a certain pattern, and the back of the back contact battery piece 111 of the head piece, tail piece and middle piece of each long battery string 110 is provided with a busbar fixing adhesive layer 120 and an insulating isolation strip 130, wherein the function of the insulating isolation strip 130 is to separate the opposite electrodes and bond on the interconnection strip of the opposite electrodes, that is, to bond on the second interconnection strip 113. The material of the insulating isolation strip 130 includes but is not limited to PET material, and the width of the insulating isolation strip 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 strip 113, but the insulating isolation strip 130 is spaced from the busbar fixing adhesive layer 120, which can avoid affecting the bonding effect of the busbar fixing adhesive layer 120. The function of the busbar fixing adhesive layer 120 is to fix the busbar 150 with the back of the back contact battery piece 111, in order to avoid the busbar fixing adhesive layer 120 affecting the lap joint between the busbar 150 and the first interconnection strip 112, the busbar fixing adhesive layer 120 should be located on both sides of the first interconnection strip 112, but not contact the first interconnection strip 112 and the insulating isolation strip 130.

[0135] In summary, the preparation method of the back contact cell piece 111 and the back contact cell piece 111 provided by the embodiment of the present application first prepare a long cell string 110 composed of a plurality of back contact cell pieces 111 arranged in a first direction, wherein the back surface of the back contact cell piece 111 of the first piece, the tail piece and the middle piece is formed with a busbar fixing adhesive layer 120 arranged intermittently in a second direction, and the back surface of the plurality of back contact cell pieces 111 is provided with a first interconnection strip 112 and a second interconnection strip 113, and the first interconnection strip 112 and the second interconnection strip 113 are arranged at the intermittent openings of the busbar fixing adhesive layer 120. Then, a plurality of long cell strings 110 are laid on the substrate according to a preset pattern. Then, an insulating isolation strip 130 is arranged on the second interconnection strip 113 at the intermittent openings of the busbar fixing adhesive layer 120. Then, a busbar 150 is arranged on the insulating isolation strip 130 and the busbar fixing adhesive layer 120, the insulating isolation strip 130 can electrically isolate the busbar 150 and the second interconnection strip 113, the busbar fixing adhesive layer 120 can fix the busbar 150, and the busbar 150 can be in contact with the first interconnection strip 112. Finally, a back plate 160 is laid on the long cell string 110, and the formed battery assembly is laminated and welded to complete the welding and fixing between the first interconnection strip 112, the second interconnection strip 113 and the back contact cell piece 111, and the welding and fixing between the busbar 150 and the first interconnection strip 112. Compared with the prior art, the embodiment of the present application can arrange the busbar 150 on the insulating isolation strip 130 and the busbar fixing adhesive layer 120 on the back surface of the back contact cell piece 111, so as to hide the busbar 150 on the back surface of the battery, increase the size of the battery, improve the space utilization of the assembly, and improve the power of the assembly. At the same time, the busbar fixing adhesive layer 120 is prepared in advance, so that the busbar 150 can be fixed by the busbar fixing adhesive layer 120, avoiding high-temperature welding before lamination, thereby avoiding high-temperature welding on the edge of the cell piece in the conventional technology. Moreover, the low-temperature lamination and welding process is adopted to realize the welding and connection between the busbar 150 and the interconnection strip, which can effectively avoid the warping of the cell piece, reduce the risk of hidden cracks or broken pieces, and improve the quality and yield of the battery.

[0136] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope 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) includes a plurality of back contact battery sheets (111) arranged sequentially along a first direction. The back side of the back contact battery sheets (111) of the first sheet, the last sheet and the middle sheet are formed with a busbar fixing adhesive layer (120) intermittently arranged along a second direction. The back side of the plurality of back contact battery sheets (111) is provided with a first interconnecting strip (112) and a second interconnecting strip (113) intermittently arranged along the first direction. The first interconnecting strip (112) and the second interconnecting strip (113) are alternately and spaced along the second direction at the intermittent opening of the busbar fixing adhesive layer (120) for connecting adjacent back contact battery sheets (111). The first direction is perpendicular to the second direction. Multiple long battery strings (110) are laid 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 in the same straight line direction; A busbar (150) is provided on the insulating isolation strip (130) and the busbar fixing adhesive layer (120), wherein the insulating isolation strip (130) is used to electrically isolate the busbar (150) and the second interconnecting strip (113), and the busbar fixing adhesive layer (120) is used to bond and fix the busbar (150) and make the busbar (150) contact the first interconnecting strip (112); A backplate (160) is laid on the long battery string (110) to form a battery assembly; The battery assembly is laminated and welded so that the first interconnect strip (112) and the second interconnect strip (113) are welded and fixed to the back contact battery cell (111), and the busbar (150) is welded and fixed to the first interconnect strip (112); The busbar fixing adhesive layer (120) is spaced apart from the first interconnecting strip (112) and the second interconnecting strip (113), and the busbar fixing adhesive layer (120) is spaced apart from the insulating isolation strip (130). The busbar fixing adhesive layer (120) is used to cure after contacting the busbar (150) and the first interconnecting strip (112) to fix the busbar (150).

2. The method for preparing a back contact battery assembly according to claim 1, characterized in that, The steps for fabricating the long battery string (110) include: Provide multiple back contact battery cells (111) arranged in a string along a first direction. A busbar fixing adhesive layer (120) is printed on the back side of the back contact cell (111) of the first cell, the last cell and the middle cell, wherein the busbar fixing adhesive layer (120) is intermittently disposed along the second direction. A first interconnecting strip (112) and a second interconnecting strip (113) are alternately arranged on the back side of a plurality of back contact battery cells (111) along a second direction, so that the plurality of back contact battery cells (111) are connected in series through the first interconnecting strip (112) and the second interconnecting strip (113) to form a long battery string (110), wherein the first interconnecting strip (112) and the second interconnecting strip (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, Prior to the step of printing and forming a busbar fixing adhesive layer (120) on the back side of the back contact cell (111) of the first, last, and middle cells, the preparation method further includes: 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). The interconnect fixing adhesive layer (114) is used to fix the first interconnect strip (112) and the second interconnect strip (113), and the interconnect fixing adhesive layer (114) is spaced apart from the bus fixing adhesive layer (120).

4. The method for preparing a back contact battery assembly according to claim 3, characterized in that, The interconnecting adhesive layer (114) is a heat-curing adhesive, and the busbar adhesive layer (120) is a UV-curing adhesive; or, The interconnecting fixing adhesive layer (114) is a UV fixing adhesive, and the bus fixing adhesive layer (120) is a heat-curing adhesive.

5. The method for preparing a back-contact battery assembly according to claim 2, characterized in that, The step of setting alternating first interconnect strips (112) and second interconnect strips (113) on the back of the plurality of back-contact battery cells (111) includes: According to a preset pattern, a first interconnecting strip (112) and a second interconnecting strip (113) are alternately laid on the back of a plurality of back contact battery cells (111) arranged along the first direction in the second direction to form a first battery string (115). According to a preset pattern, a second interconnecting strip (113) and a first interconnecting strip (112) are alternately laid on the back of a plurality of back contact battery cells (111) arranged along the first direction in the second direction 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 multiple long battery strings (110) on a substrate according to a preset pattern includes: Provide a substrate with a front adhesive film layer; The first battery string (115) and the second battery string (116) are alternately laid on the substrate along the second direction; The first battery string (115) and the second battery string (116) are symmetrical in the second direction.

7. The method for preparing a back contact battery assembly according to claim 1, characterized in that, The steps for fabricating the long battery string (110) include: Provide multiple back contact battery cells (111) arranged in a string along a first direction. A first interconnecting strip (112) and a second interconnecting strip (113) are alternately arranged on the back side of the plurality of back contact battery cells (111) along the second direction, so that the plurality of back contact battery cells (111) are connected in series through the first interconnecting strip (112) and the second interconnecting strip (113) to form a long battery string (110). A busbar fixing adhesive layer (120) is formed on both sides of the first interconnecting strip (112) and the second interconnecting strip (113) on the back contact cell (111) of the first cell, the last cell and the middle cell, wherein the busbar fixing adhesive layer (120) is intermittently arranged along the second direction and spaced apart from the first interconnecting strip (112) and the second interconnecting strip (113).

8. The method for preparing a back contact battery assembly according to claim 1, characterized in that, The step of setting an insulating isolation strip (130) on the second interconnecting strip (113) at the intermittent opening of the busbar fixing adhesive layer (120) includes: An isolation area on the second interconnecting strip (113) is defined 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); An insulating isolation strip (130) is laid on the top side and side wall of the second interconnecting 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 interconnecting strip (113) and the insulating isolation strip (130).

9. The method for preparing a back contact battery assembly according to claim 1, characterized in that, The step of setting the busbar (150) on the insulating insulating strip (130) and the busbar fixing adhesive layer (120) includes: Busbars (150) are aligned and laid on the corresponding busbar fixing adhesive layer (120) and insulating isolation strip (130) 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 sheet (111) of the first and last sheets are staggered with the busbars (150) on the back contact battery sheet (111) of the middle sheet along the second direction; Press down the busbar (150) to make the busbar (150) contact the first interconnecting bar (112); The flow fixation 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) along the second direction on the corresponding busbar fixing adhesive layer (120) and the insulating isolation strip (130) includes: Align the clearance groove (151) on the bottom side of the busbar (150) with the insulating isolation strip (130). The busbar (150) is laid on the corresponding busbar fixing adhesive layer (120) and the insulating isolation strip (130).

11. The method for preparing a back contact battery assembly according to claim 1, characterized in that, The step of laying the backplate (160) on the long battery string (110) includes: A back adhesive film layer and a back plate (160) are sequentially laid on the long battery string (110). The back adhesive film layer covers the back of the plurality of back contact cells (111) and the busbar (150).

12. The method for preparing a back contact battery assembly according to claim 1, characterized in that, The step of laminating the battery assembly includes: The battery assembly is placed in a laminator for vacuuming and heating to a preset temperature so that the first interconnect strip (112) and the second interconnect strip (113) form an alloy weld with the electrode of the back contact battery cell (111), and the busbar (150) forms an alloy weld with the first interconnect strip (112).

13. The method for preparing a back contact battery assembly according to claim 12, characterized in that, The preset temperature is between 135℃ and 155℃.

14. A back-contact battery assembly, manufactured using the method for preparing a back-contact battery assembly as described in any one of claims 1-13, characterized in that, The back contact battery assembly includes: substrate; Multiple long battery strings (110) are laid on the substrate. Each long battery string (110) includes multiple back contact battery sheets (111) arranged sequentially along a first direction. The back side of the back contact battery sheets (111) of the first sheet, the last sheet and the middle sheet are formed with a busbar fixing adhesive layer (120) intermittently arranged along a second direction. The back side of the multiple back contact battery sheets (111) is provided with a first interconnecting strip (112) and a second interconnecting strip (113) intermittently arranged along the first direction. The first interconnecting strip (112) and the second interconnecting strip (113) are alternately and spaced 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 is perpendicular to the second direction. An insulating isolation strip (130) is disposed on the second interconnecting 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) are arranged in the same straight line direction; The busbar (150) is disposed on the insulating isolation strip (130) and the busbar fixing adhesive layer (120). The insulating isolation strip (130) is used to electrically isolate the busbar (150) and the second interconnecting strip (113). The busbar fixing adhesive layer (120) is used to bond and fix the busbar (150). The busbar (150) is welded and fixed to the first interconnecting strip (112).

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). The first battery string (115) and the second battery string (116) are alternately laid on the substrate along a second direction. The first interconnecting strip (112) and the second interconnecting strip (113) on the first battery string (115) and the first interconnecting strip (112) and the second interconnecting strip (113) on the second battery string (116) are symmetrical in the second direction.

16. The back contact battery assembly according to claim 14, characterized in that, Each of the long battery strings (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+1)th 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+1)th back contact battery cell (111) are connected in parallel.

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