Method for manufacturing a battery string and battery string

Abstract

The application discloses a battery string preparation method and a battery string, and belongs to the photovoltaic technical field. The battery string preparation method comprises the following steps: providing a cell sheet, and the surface of the cell sheet is provided with an electrode structure; preparing a solder block on the electrode structure of the cell sheet, each solder block comprises at least two solder sub-blocks arranged at intervals along a first direction; laying a solder strip on the surface of the cell sheet along a second direction, the solder strip is placed on the solder block and in contact with the at least two solder sub-blocks, and the first direction and the second direction are perpendicular and parallel to the plane where the cell sheet is located; and welding the solder strip and the solder block to connect different cell sheets to form a battery string. The method can support the solder strip by the solder block, can reduce the deviation of the solder strip, can reduce the occurrence probability of false welding or missed welding, and is helpful to improve the product yield and overall power generation performance.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, and in particular relates to a method for preparing a battery string and the battery string itself. Background Technology

[0002] Solar cell technology, as a crucial solution for sustainable clean energy, has garnered significant attention in recent years. During module fabrication, multiple solar cells are typically welded into strings using solder ribbons, followed by processes such as laying and lamination to complete the module encapsulation. When placing the solder ribbons during the welding process, a welding material is usually pre-installed on the solar cells to enhance the connection between them. However, the presence of this welding material can cause the solder ribbons to shift, potentially leading to incomplete or missing welds, reducing product yield, and impacting the overall power generation performance of the module. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a method for preparing a battery string and a battery string that can reduce solder strip misalignment, lower the probability of incomplete or missing solder joints, and help improve product yield and overall power generation performance.

[0004] In a first aspect, this application provides a method for preparing a battery string, comprising:

[0005] A battery cell is provided, wherein the surface of the battery cell is provided with an electrode structure;

[0006] Solder blocks are prepared on the electrode structure of the battery cell, each solder block comprising at least two solder sub-blocks spaced apart along a first direction;

[0007] The solder ribbon is laid on the surface of the battery cell along the second direction. The solder ribbon is placed on the solder block and in contact with the at least two solder sub-blocks. The first direction and the second direction are perpendicular to each other and are both parallel to the plane where the battery cell is located.

[0008] The solder strips are welded to the solder block to connect different battery cells to form a battery string.

[0009] According to the battery string preparation method of this application, by preparing solder blocks on the battery cell, each solder block includes at least two solder sub-blocks arranged at intervals along a first direction, and laying the solder strip on the surface of the battery cell along a second direction, each solder sub-block forms a support point for the solder strip and supports the solder strip along the first direction, the offset of the solder strip can be reduced, the probability of cold solder or missing solder is reduced, and the product yield and overall power generation performance can be improved.

[0010] According to one embodiment of this application, the fabrication of solder blocks on the electrode structure of the battery cell includes:

[0011] Solder is printed on the electrode structure according to the solder printing pattern;

[0012] The solder block is obtained by performing a curing process.

[0013] The solder printing pattern includes at least two sub-block printing patterns arranged at intervals along the first direction, the at least two sub-block printing patterns being used to form the at least two solder sub-blocks.

[0014] According to one embodiment of this application, the printed pattern of the sub-block is a circle, triangle, quadrilateral or irregular shape.

[0015] According to one embodiment of this application, the at least two solder sub-blocks include two end solder sub-blocks located at both ends of the solder block, the first ends of the two end solder sub-blocks are close to each other, the second ends of the two end solder sub-blocks are far apart from each other, and the size of the end solder sub-blocks gradually decreases from the first end to the second end along the second direction.

[0016] According to one embodiment of this application, the end solder sub-block is triangular in the projection area of ​​the battery cell, with the first end corresponding to the base of the triangle and the second end corresponding to the apex of the triangle.

[0017] According to one embodiment of this application, the dimension of the end solder sub-block along the first direction is d1, the dimension of the first end along the second direction is L1, and the distance between the first ends of the two end solder sub-blocks is d2.

[0018] When the solder block is located in the fine grid of the electrode structure, the following conditions are met: 1 / 3W≤d1≤2 / 3W, 1 / 3W≤d2≤2 / 3W, 1 / 2W≤L1≤2W, where W is the dimension of the solder strip along the first direction.

[0019] According to one embodiment of this application, the dimension of the end solder sub-block along the first direction is d1, the dimension of the first end along the second direction is L1, and the distance between the first ends of the two end solder sub-blocks is d2.

[0020] When the solder block is located on the pad of the electrode structure, the following conditions are met: 1 / 2W≤d1≤3 / 2W, 1 / 3W≤d2≤1W, W≤L1≤2W, where W is the dimension of the solder strip along the first direction.

[0021] According to one embodiment of this application, the size of the solder block located at the fine grid of the electrode structure is smaller than the size of the solder block located at the pad of the electrode structure.

[0022] According to one embodiment of this application, after the solder strip and the solder block are soldered, the projection area of ​​the solder block on the battery cell is located within the projection area of ​​the solder strip on the battery cell.

[0023] According to one embodiment of this application, the cross-section of the welding strip is circular, triangular, or quadrilateral.

[0024] Secondly, this application provides a battery string, which is prepared by the battery string preparation method described in the first aspect above.

[0025] According to the battery string of this application, by preparing solder blocks on the battery cells, each solder block includes at least two solder sub-blocks arranged at intervals along a first direction, and laying the solder strip on the surface of the battery cells along a second direction, each solder sub-block forms a support point for the solder strip and supports the solder strip along the first direction, the offset of the solder strip can be reduced, the probability of cold solder or missing solder is reduced, and it helps to improve product yield and overall power generation performance.

[0026] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0027] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0028] Figure 1 This is a schematic flowchart of the battery string preparation method provided in the embodiments of this application;

[0029] Figure 2 This is one of the schematic diagrams of solder strip offset in related technologies;

[0030] Figure 3 This is the second schematic diagram of solder strip offset in related technologies;

[0031] Figure 4 This is one of the schematic diagrams of the solder ribbon being laid on the surface of the battery cell according to an embodiment of this application;

[0032] Figure 5 This is a second schematic diagram of the solder ribbon being laid on the surface of the battery cell according to an embodiment of this application;

[0033] Figure 6 This is one of the structural schematic diagrams of the solder block provided in the embodiments of this application;

[0034] Figure 7 This is a second schematic diagram of the solder block structure provided in the embodiments of this application;

[0035] Figure 8This is a schematic diagram of the solder block located in the fine gate according to an embodiment of this application;

[0036] Figure 9 This is a schematic diagram of the solder block located on the pad according to an embodiment of this application;

[0037] Figure 10 This is a schematic diagram of the back contact battery provided in an embodiment of this application.

[0038] Figure label:

[0039] Solar cell 200, fine grid 310, main grid 320, pad 330.

[0040] Solder strip 400, solder block 500, solder sub-block 510, insulating adhesive 600. Detailed Implementation

[0041] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0042] The following is for reference. Figures 1-10 This application describes a method for preparing a battery string and a battery string according to embodiments thereof.

[0043] like Figure 1 As shown, the battery string preparation method of this application embodiment includes steps 110 and 140.

[0044] Step 110: Provide battery cell 200.

[0045] In this step, the surface of the provided solar cell 200 is provided with an electrode structure, which may include grid lines, pads 330 (PADs), and other structures.

[0046] Taking the 200-cell battery as an example, which is a back-contact battery.

[0047] Multiple solar cells 200 are provided. The back contact surface of the solar cell without main grid 320 is provided with multiple fine grids 310. The fine grids 310 with opposite conductive polarities are arranged alternately to collect the current on the solar cell 200.

[0048] For a back contact battery with a main grid 320, its surface is provided with multiple fine grids 310 and multiple main grids 320. The fine grids 310 with opposite conduction polarities are arranged alternately to collect the current on the battery cell 200. The main grids 320 with opposite conduction polarities are also arranged alternately. The main grids 320 intersect and are electrically connected with the fine grids 310 with the same conduction polarity, so as to summarize and export the current collected by the fine grids 310.

[0049] Step 120: Prepare solder block 500 on the electrode structure of battery cell 200.

[0050] Each solder block 500 includes at least two solder sub-blocks 510 arranged at intervals along a first direction.

[0051] It is understandable that the first direction can be any direction parallel to the plane where the battery cell 200 is located.

[0052] In this step, solder blocks 500 are prepared on the solar cell 200. The solder blocks 500 are located on the electrode structure of the solar cell 200. Each solder block 500 includes two or more solder sub-blocks 510 arranged at intervals along a first direction.

[0053] For example, such as Figure 6 As shown, the solder block 500 includes two solder sub-blocks 510 arranged at intervals along the first direction D1, and the two solder sub-blocks 510 are arranged opposite each other and spaced apart.

[0054] In actual implementation, when the solder block 500 includes two or more solder sub-blocks 510 arranged at intervals along the first direction, it is divided into two solder sub-blocks 510 located at both ends and at least one solder sub-block 510 located in the middle.

[0055] It is understandable that multiple solder blocks 500 can be fabricated on the solar cell 200, and the position, number, and size of the solder blocks 500 are related to the type and distribution of the electrode structure on the solar cell 200.

[0056] In this embodiment, the solder block 500 is a structure made using solder, which can be, for example, but not limited to, tin, tin-lead alloy or lead-free solder.

[0057] Step 130: Lay the welding ribbon 400 on the surface of the battery cell 200 along the second direction.

[0058] In this step, solder ribbon 400 is placed on solder block 500 and in contact with at least two solder sub-blocks 510.

[0059] Specifically, the first direction and the second direction are perpendicular to and parallel to the plane containing the solar cell 200. That is, the first direction can be any direction parallel to the plane containing the solar cell 200, and the second direction can be a direction parallel to the plane containing the solar cell 200 and perpendicular to the first direction. It should be noted that "perpendicular" here includes not only absolute perpendicularity of 90 degrees, but also other approximate perpendicularity cases close to 90 degrees.

[0060] For example, such as Figure 8As shown, the first direction is the left-right direction, and the second direction is the up-down direction. The solder strip 400 is laid on the surface of the battery cell 200 along the up-down direction. The solder block 500 includes two solder sub-blocks 510 arranged at intervals along the left-right direction. The two solder sub-blocks 510 are located on both sides of the solder strip 400 and support the solder strip 400 from both sides, effectively reducing the probability of the solder strip 400 slipping to the left or right.

[0061] It is understood that when the solder block 500 includes two or more solder sub-blocks 510 arranged at intervals along the first direction, the solder sub-blocks 510 located at both ends support the solder strip 400 from both sides of the solder strip 400, and the solder sub-block 510 located in the middle can support the solder strip 400 from the middle of the solder strip 400. Each solder sub-block 510 forms a support point for the solder strip 400, supporting the solder strip 400 extending along the second direction along the first direction, that is, supporting the solder strip 400 from the transverse direction of the solder strip 400 (the direction perpendicular to the extension direction of the solder strip 400).

[0062] In this embodiment, the solder ribbon 400 is laid on the surface of the battery cell 200 along the second direction. The solder ribbon 400 is in contact with the solder block 500 on the surface of the battery cell 200. The solder ribbon 400 is in contact with at least two solder sub-blocks 510 of each solder block 500. Each solder sub-block 510 forms a support point for the solder ribbon 400 and supports the solder ribbon 400 along the first direction. This can effectively reduce the probability of the solder ribbon 400 slipping along the first direction and reduce the offset of the solder ribbon 400.

[0063] In related technologies, the soldering process involves printing wet solder paste (soldering material) onto the battery surface, followed by a high-temperature process to semi-solder the paste. During the curing process, the solder paste forms a curved surface due to the wetting principle, such as... Figure 2 As shown, solder paste B1 is located on the surface of battery C1. When a rectangular solder ribbon A1 is placed on solder paste B1, solder ribbon A1 is prone to shifting, as... Figure 3 As shown, solder paste B1 is located on the surface of battery C1. When the solder ribbon A2 with a circular cross-section is placed on solder paste B1, solder ribbon A2 is prone to shifting, which can easily lead to poor soldering or missing solder after soldering.

[0064] In this embodiment, solder blocks 500 are prepared on the battery cell 200. Each solder block 500 includes at least two solder sub-blocks 510 spaced apart along a first direction D1. Solder ribbon 400 is laid on the surface of the battery cell 200 along a second direction. Figure 4 As shown, when a rectangular solder strip 400 is placed on a solder block 500, the solder strip 400 contacts at least two solder sub-blocks 510, forming at least two support points. This provides stable support for the solder strip 400, whose contact surface with the solder block 500 is planar. Figure 5As shown, when a circular solder strip 400 is placed on a solder block 500, the solder strip 400 contacts at least two solder sub-blocks 510, forming at least two support points. The solder strip 400, whose contact surface with the solder block 500 is curved, can also play a stable supporting role. Placing the solder strip 400 on at least two solder sub-blocks 510 spaced apart along the first direction can effectively reduce the probability of the solder strip 400 slipping off and reduce the offset of the solder strip 400, which helps to improve the welding effect of subsequent processes.

[0065] It is understandable that the solder ribbon 400 is laid on the cell 200 along the second direction, and a solder ribbon 400 may have multiple solder points, that is, multiple points that contact the solder block 500. The cell 200 may have multiple solder blocks 500 arranged at intervals along the second direction.

[0066] Step 140: Weld the solder strip 400 and the solder block 500 to connect different battery cells 200 to form a battery string.

[0067] In this embodiment, the solder ribbon 400 and the solder block 500 are soldered together to connect multiple different battery cells 200 to form a battery string. During the soldering process, the solder ribbon 400 and the solder block 500 form an electrical connection, and the solder ribbon 400 can realize the current transmission between different battery cells 200.

[0068] It should be noted that when welding the solder ribbon 400 and the solder block 500, the solder block 500 will move toward the position where the solder ribbon 400 is located. When laying the solder ribbon 400 on the battery cell 200, the axis of the solder ribbon 400 along its length can be aligned with the midpoint of the solder block 500. For a solder block 500 that includes two solder sub-blocks 510, the solder ribbon 400 is placed in the center between the two solder sub-blocks 510. The solder sub-blocks 510 on both sides of the axis of the solder ribbon 400 are evenly distributed, which helps to improve the subsequent welding effect.

[0069] In related technologies, for cases where the solder ribbon is prone to shifting, a film layer is laminated to fix the film layer, which reduces the shifting of the positive and negative electrode solder ribbons during the process of battery modules without a main grid back contact. However, adding a film layer will increase the cost and complicate the manufacturing process. Furthermore, the lamination process can easily cause the solder to fall off, and there is still a high probability of incomplete or missing soldering.

[0070] In this embodiment, by improving the shape of the solder block 500, a solder block 500 consisting of at least two solder sub-blocks 510 spaced apart along a first direction is prepared on the battery cell 200. The solder ribbon 400 is placed on the solder block 500, and the solder ribbon 400 is in contact with at least two solder sub-blocks 510 to form at least two support points. This can effectively reduce the probability of the solder ribbon 400 slipping off and reduce the offset of the solder ribbon 400. Furthermore, setting the solder sub-blocks 510 to be spaced apart not only allows the solder ribbon 400 to be firmly fixed on the solder block 500, but also reduces the amount of solder used in the area between the solder sub-blocks 510, effectively reducing the manufacturing cost, reducing the offset of the solder ribbon 400, and reducing the probability of cold solder joints or missing solder joints, which helps to improve product yield and overall power generation performance.

[0071] According to the battery string preparation method provided in the embodiments of this application, by preparing solder blocks 500 on the battery cell 200, each solder block 500 includes at least two solder sub-blocks 510 arranged at intervals along a first direction, and laying solder ribbon 400 on the surface of the battery cell 200 along a second direction, each solder sub-block 510 forms a support point for the solder ribbon 400 and supports the solder ribbon 400 along the first direction, the offset of the solder ribbon 400 can be reduced, the probability of cold solder or missing solder is reduced, and it helps to improve product yield and overall power generation performance.

[0072] In some embodiments, step 120, preparing a solder block 500 on the electrode structure of the battery cell 200, may include:

[0073] Solder is printed onto the electrode structure according to the solder printing pattern;

[0074] After solidification, solder block 500 is obtained;

[0075] The solder printing pattern includes at least two sub-block printing patterns arranged at intervals along a first direction, the at least two sub-block printing patterns being used to form at least two solder sub-blocks 510.

[0076] In this embodiment, solder is printed on the electrode structure of the cell 200 using solder printing patterns. One solder printing pattern can correspond to the printing of one solder block 500. The solder printing pattern is a double-hole or multi-hole pattern, including two or more sub-block printing patterns arranged at intervals along a first direction. Each sub-block printing pattern is used to print one solder sub-block 510.

[0077] Taking solder as an example, solder block 500 includes two solder sub-blocks 510.

[0078] According to the solder printing pattern, wet solder paste is printed on the surface of the cell 200. The solder paste is cured by a high-temperature process to prevent it from falling off the production line during the process. During the curing process, the solder paste forms a curved surface on the cell 200 due to the wetting principle. The solder ribbon 400 is laid on the surface of the cell 200 along the second direction. Two solder sub-blocks 510 are arranged opposite each other along the first direction on both sides of the solder ribbon 400. Each solder sub-block 510 forms a support point for the solder ribbon 400. Supporting the solder ribbon 400 from both sides can reduce the offset of the solder ribbon 400, reduce the probability of cold solder or missing solder, and help improve product yield and overall power generation performance.

[0079] In actual implementation, the solder is printed according to the solder printing pattern. The solder is flat away from the surface of the battery cell 200. After curing, the solder becomes curved away from the surface of the battery cell 200.

[0080] It should be noted that during the curing process, the solder corresponding to each solder sub-block 510 is individually wetted. After curing, an independent bump (i.e., solder sub-block 510) is formed on the battery cell 200. The solder ribbon 400 is placed on the solder block 500 and is in contact with at least two solder sub-blocks 510. Each solder sub-block 510 forms a support point for the solder ribbon 400, reducing the offset of the solder ribbon 400. After welding, at least two solder sub-blocks 510 can be fused into one point or remain spaced apart.

[0081] In some embodiments, the printed graphics of the sub-blocks are circles, triangles, quadrilaterals, or irregular shapes.

[0082] In this embodiment, solder can be printed on the battery cell 200 by selecting a circular, triangular, quadrilateral, or irregularly shaped solder printing pattern for the sub-block printing pattern, depending on the type and distribution of the electrode structure on the battery cell 200.

[0083] It is understandable that solder blocks 500 at different locations on the battery cell 200 can be obtained by printing and curing solder printing patterns of different shapes.

[0084] It should be noted that the printed pattern of the sub-block can be circular, triangular, quadrilateral or irregular. After the solder is printed on the battery cell 200 according to the solder printing pattern, the projection of the solder on the battery cell 200 forms a circular, triangular, quadrilateral or irregular shape. After curing, the solder moves away from the surface of the battery cell 200 to form a curved surface. The projection of the solder on the battery cell 200 can maintain a circular, triangular, quadrilateral or irregular shape.

[0085] Quadrilaterals can be rhombuses, rectangles, squares, etc., while irregular shapes can refer to polygons with more than four sides.

[0086] For example, if the sub-block printing pattern is a triangle, solder is printed on the battery cell 200 according to the double-triangle pattern, and after curing, it forms a shape like... Figure 6 The solder block 500 shown includes two or more solder sub-blocks 510 arranged at intervals along a first direction, and the projection of each solder sub-block 510 on the solar cell 200 maintains a triangular shape.

[0087] It is understood that the solder block 500 includes at least two (i.e., two or more) solder sub-blocks 510, and the at least two solder sub-blocks 510 include end solder sub-blocks located at both ends of the solder block 500. That is, the two solder sub-blocks 510 located at both ends of the solder block 500 are called end solder sub-blocks.

[0088] In some embodiments, the first ends of the two end solder sub-blocks are close to each other, the second ends of the two end solder sub-blocks are far apart from each other, and the size of the end solder sub-blocks along the second direction gradually decreases from the first end to the second end.

[0089] It should be noted that when the solder block 500 includes two or more solder sub-blocks 510, the end solder sub-blocks located at both ends of the solder block 500 have a first end and a second end, and the shape of the middle solder sub-block 510 can be the same as or different from the shape of the end solder sub-blocks located at both ends.

[0090] In this embodiment, each end solder sub-block located at both ends of the solder block 500 has a first end and a second end. The first end and the second end are arranged opposite to each other along a first direction. The first ends of the two end solder sub-blocks are close to each other and spaced apart, while the second ends of the two end solder sub-blocks are far apart. Each end solder sub-block has a shape in which the size gradually decreases from the first end to the second end along a second direction.

[0091] In actual operation, during welding, the solder block 500 will move toward the position of the solder strip 400. The solder strip 400 can be placed in the center between the two end solder sub-blocks. The first end of the two end solder sub-blocks is close to each other and has a relatively larger size, which can provide support for the solder strip 400 so that the solder strip 400 and the first end form a stable support point.

[0092] In this embodiment, the size of the end solder sub-block gradually decreases from the first end to the second end along the second direction. Compared with the rectangular solder of the same printing material in the related art, the printing width of the solder block 500 along the first direction can be increased to increase the tolerance of the placement accuracy of the solder strip 400. Compared with the rectangular solder of the same length in the related art, the printing material of the solder can be reduced, thereby reducing the battery production cost.

[0093] It should be noted that the solder raw materials used to prepare solder block 500 may include acidic flux. During the soldering process, the flux may not completely evaporate, resulting in residue. The molecular bonds of the acidic flux may be broken under light, causing the flux to corrode the battery cell 200.

[0094] In this embodiment, the second ends, which are far apart from each other, are distributed on both sides of the solder strip 400. The second ends are relatively small in size, and the portion of the solder block 500 exposed above the solder strip 400 is small, which makes it easy to retract below the solder strip 400 during welding. That is, after welding is completed, the solder strip 400 can cover the solder block 500, reducing the corrosion caused by the exposed solder block 500.

[0095] In some embodiments, the end solder sub-blocks are triangular in the projection area of ​​the battery cell 200, with the first end corresponding to the base of the triangle and the second end corresponding to the apex of the triangle.

[0096] In this embodiment, the end solder sub-block is triangular in the projection area of ​​the battery cell 200. The first end corresponds to the base of the triangle, and the second end corresponds to the apex of the triangle. The bases of the two triangles projected by the solder block 500 are close to each other and spaced apart, while the apexes of the two triangles are far apart. Along the second direction, the size of the triangle corresponding to each end solder sub-block gradually decreases from the base to the apex.

[0097] like Figure 6 As shown, with the same amount of solder, the end solder sub-blocks in the projected area of ​​the cell 200, which are triangular, can increase the overall printing width of the solder block 500 in the first direction D1. The solder ribbon 400 is laid on the cell 200 along the second direction D2. The solder ribbon 400 can be placed in the center between the two triangles. The solder ribbon 400 is in contact with both end solder sub-blocks. The base of the two triangles provides stable support for the solder ribbon 400. The amount of solder used at the apex of the two triangles is small, which makes it easy to retract below the solder ribbon 400 during welding and reduce the corrosion of the cell 200.

[0098] The design dimensions of the end solder sub-block are described in detail below.

[0099] The solder block 500 has two end solder sub-blocks located at both ends, which have a first end and a second end. The first end and the second end are arranged opposite to each other along a first direction. The first ends of the two end solder sub-blocks are close to each other and spaced apart, while the second ends of the two end solder sub-blocks are far apart. Each end solder sub-block has a shape in which the size gradually decreases from the first end to the second end along a second direction.

[0100] like Figure 7 As shown, the dimension of the end solder sub-blocks located at both ends of the solder block 500 along the first direction is d1, the dimension of the first end along the second direction is L1, and the distance between the first ends of the two end solder sub-blocks is d2.

[0101] Taking the first direction D1 as the horizontal direction and the second direction D2 as the vertical direction as an example.

[0102] d1 is the lateral length of the end solder sub-block, d2 is the lateral spacing between the two end solder sub-blocks, the end solder sub-blocks have a shape in which the longitudinal dimension gradually decreases from the first end to the second end, and L1 is the maximum value of the longitudinal length of the end solder sub-block.

[0103] In some embodiments, when the solder block 500 is located in the fine grid 310 of the electrode structure, the following conditions are met: 1 / 3W≤d1≤2 / 3W, 1 / 3W≤d2≤2 / 3W, 1 / 2W≤L1≤2W, where W is the dimension of the solder strip 400 along the first direction.

[0104] It is understandable that W is the dimension of the solder strip 400 along the first direction. For a solder strip 400 with a circular cross-section, W can be the diameter of the solder strip 400. For a solder strip 400 with a rectangular cross-section, W can be the width of the solder strip 400.

[0105] In this embodiment, for the solder block 500 located in the fine grid 310, the lateral length of the end solder sub-block and the lateral spacing between the two end solder sub-blocks can be 1 / 3 to 2 / 3 times the width (or diameter) of the solder strip 400, so that the overall lateral length (d2+2d1) of the solder block 500 is 1 to 2 times the width (or diameter) of the solder strip 400, which facilitates the placement of the solder strip 400. At the same time, the solder block 500 will not exceed the solder strip 400 by too much in the first direction, which can control printing costs and reduce corrosion (for acidic flux scenarios).

[0106] For the solder block 500 located in the fine gate 310, the maximum longitudinal length of the end solder sub-block can be 1 / 2 to 2 times the width (or diameter) of the solder strip 400. The specific value of the maximum longitudinal length can be adjusted according to the total length of the solder strip 400. The maximum length of the solder strip 400 in contact with a single solder block 500 in the longitudinal direction (i.e., the second direction) is 1 / 2 to 2 times the width (or diameter) of the solder strip 400, so that the solder block 500 and the solder strip 400 can form a stable solder joint. In some other embodiments, when the solder block 500 is located in the pad 330 of the electrode structure, the following conditions are met: 1 / 2W ≤ d1 ≤ 3 / 2W, 1 / 3W ≤ d2 ≤ 1W, W ≤ L1 ≤ 2W, where W is the dimension of the solder strip 400 along the first direction.

[0107] Understandably, pad 330 is a metallized area used to achieve electrical connection and collect grid current. During module packaging, pad 330 is the location where cell 200 is soldered to ribbon 400 to achieve a strong connection between cells 500.

[0108] In this embodiment, for the solder block 500 located on the pad 330, the lateral length of the end solder sub-block can be 1 / 2 to 3 / 2 times the width (or diameter) of the solder strip 400, and the lateral spacing between the two end solder sub-blocks can be 1 / 3 to 1 times the width (or diameter) of the solder strip 400, so that the overall lateral length (d2+2d1) of the solder block 500 is 4 / 3 to 4 times the width (or diameter) of the solder strip 400. At the same time, the maximum value of the longitudinal length of the end solder sub-block can be 1 to 2 times the width (or diameter) of the solder strip 400. The solder block 500 located on the pad 330 does not contact the gate line. Under the premise of reducing the risk of gate line breakage, the larger size of the solder block 500 in the first and second directions can effectively enhance the welding reliability and facilitate the placement of the solder strip 400.

[0109] In some embodiments, the size of the solder block 500 located at the fine gate 310 is smaller than the size of the solder block 500 located at the pad 330.

[0110] It should be noted that the size of the solder block 500 located at the fine gate 310 can be slightly smaller than the size of the solder block 500 located at the pad 330, which can reduce the probability of the fine gate 310 breaking during soldering and improve product yield.

[0111] Taking the solder block 500 as an example, which includes two end solder sub-blocks, and the end solder sub-blocks are triangular in the projection area of ​​the solar cell 200.

[0112] L1 is the maximum longitudinal length of the end solder sub-block, i.e., the side length of the base of the triangle; d1 is the transverse length of the end solder sub-block, i.e., the height from the base of the triangle to the apex; d2 is the transverse spacing between the two end solder sub-blocks, i.e., the spacing between the bases of the two triangles; and W is the dimension of the solder strip 400 along the first direction.

[0113] like Figure 8 As shown, the fine grid 310 on the solar cell 200 extends along the first direction D1, and multiple fine grids 310 are spaced apart along the second direction D2. Solder blocks 500 are disposed on the fine grids 310. Each solder block 500 includes a triangular end solder sub-block in the projection area of ​​the solar cell 200. Solder ribbon 400 is laid on the solar cell 200 along the second direction D2. The size of the solder block 500 satisfies 1 / 3W≤d1≤2 / 3W, 1 / 3W≤d2≤2 / 3W, and 1 / 2W≤L1≤2W.

[0114] like Figure 9As shown, the fine grid 310 on the solar cell 200 extends along the first direction D1, and multiple fine grids 310 are spaced apart along the second direction D2. The main grid 320 extends along the first direction, and solder blocks 500 are disposed on the pads 330 on the main grid 320. Each solder block 500 includes a triangular end solder sub-block in the projection area of ​​the solar cell 200. Solder ribbon 400 is laid on the solar cell 200 along the second direction D2. The dimensions of the solder block 500 satisfy 1 / 2W≤d1≤3 / 2W, 1 / 3W≤d2≤1W, and W≤L1≤2W.

[0115] In this embodiment, the d2+2d1 of the solder block 500 at the fine gate 310 can be smaller than the d2+2d1 of the solder block 500 at the pad 330, and the L1 of the solder block 500 at the fine gate 310 can be smaller than the L1 of the solder block 500 at the pad 330. That is, the size of the solder block 500 at the fine gate 310 is slightly smaller than the size of the solder block 500 at the pad 330. The size of the fine gate 310 is generally smaller than the size of the pad 330. The size design of the solder block 500 can effectively reduce the probability of the fine gate 310 being broken.

[0116] In actual implementation, the size of the end solder sub-block is adjusted according to the size of the solder strip 400 along the first direction, and can be applied to batteries with main grid 320 (with solder pad 330) and without main grid 320.

[0117] It should be noted that the size of the end solder sub-block is related to the size of the sub-block printing pattern in the solder printing pattern. The size of the sub-block printing pattern can be designed according to the size of the end solder sub-block. Solder is printed on the electrode structure according to the solder printing pattern. After curing, two end solder sub-blocks of the required size are obtained.

[0118] In some embodiments, after the solder ribbon 400 and the solder block 500 are soldered, the projection area of ​​the solder block 500 on the cell 200 is located within the projection area of ​​the solder ribbon 400 on the cell 200.

[0119] The solder raw materials used to prepare solder block 500 may include acidic flux. During the soldering process, the flux may not completely evaporate, resulting in residue. The molecular bonds of the acidic flux may be broken under light, causing the flux to corrode the battery cell 200.

[0120] In this embodiment, after the solder ribbon 400 and the solder block 500 are soldered, the projection area of ​​the solder block 500 on the solar cell 200 is located within the projection area of ​​the solder ribbon 400 on the solar cell 200. The solder ribbon 400 shields the solder block 500, reducing the exposure of the solder block 500, effectively reducing the corrosion of the solar cell 200, and helping to extend the service life of the solar cell 200.

[0121] In actual implementation, after curing, two or more independent solder sub-blocks 510 are formed on the solar cell 200. The solder ribbon 400 is placed on the solder block 500 and is in contact with each solder sub-block 510. After welding, the multiple solder sub-blocks 510 can be fused into one point or remain spaced apart. The projection area of ​​the solder block 500 on the solar cell 200 is located within the projection area of ​​the solder ribbon 400 on the solar cell 200. The solder ribbon 400 blocks the solder sub-blocks 510 that are fused into one point or spaced apart.

[0122] In some embodiments, the cross-section of the solder strip 400 is circular, triangular, or quadrilateral.

[0123] The quadrilateral can be a rhombus, rectangle, square, or other shapes.

[0124] In this embodiment, the solder ribbon 400 is laid on the surface of the battery cell 200 along the second direction. The solder ribbon 400 is in contact with at least two solder sub-blocks 510 of each solder block 500. Each solder sub-block 510 forms a support point for the solder ribbon 400, which can support the solder ribbon 400 with a cross-section of circular, triangular, quadrilateral or other types, effectively reducing the probability of the solder ribbon 400 slipping and reducing the offset of the solder ribbon 400.

[0125] For example, such as Figure 4 As shown, when the rectangular solder strip 400 is placed on the solder block 500, the solder strip 400 contacts both solder sub-blocks 510, forming two support points. The solder strip 400, whose contact surface with the solder block 500 is flat, can play a stable supporting role.

[0126] For example, such as Figure 5 As shown, when the circular solder strip 400 is placed on the solder block 500, the solder strip 400 contacts both solder sub-blocks 510, forming two support points. The solder strip 400, whose contact surface with the solder block 500 is curved, can also play a stable supporting role.

[0127] It is understood that the battery string fabrication method provided in this application embodiment can be applied to various battery types that form battery strings by connecting battery cells 200 with solder blocks 500 and solder ribbons 400, such as back contact cells (BC), passivated emitter and rear cell (PERC), tunnel oxide passivated contact cells (TOPCon), and intrinsic thin-layer heterojunction cells (HJT).

[0128] Among them, the back contact battery is a type of battery in which both the positive and negative electrodes are placed on the back, reducing the obstruction of sunlight by the electrodes being on the front and improving the photoelectric conversion efficiency of the battery.

[0129] In practice, for back-contact batteries, insulating adhesive 600 can be printed on the irregular grid lines on the back of the battery cell 200, such as... Figure 10 As shown, the fine grid 310 on the left and the fine grid 310 on the right have opposite conductive polarities. After printing the insulating adhesive 600, the short circuit of the cell 200 can be improved. The main grid 320 and the top of the insulating adhesive 600 form a height difference, and the solder ribbon 400 cannot directly contact the silver paste of the main grid 320, which may lead to poor soldering.

[0130] Solder blocks 500 are printed at the main busbar 320 of the cell 200, such that the top of the solder block 500 is higher than the top of the insulating adhesive 600. The solder block 500 realizes the connection between the solder strip 400 and the cell 200. Each solder block 500 includes at least two solder sub-blocks 510 arranged at intervals along the first direction. Each solder sub-block 510 forms a support point for the solder strip 400 and supports the solder strip 400 from both sides, which can reduce the offset of the solder strip 400 and reduce the probability of cold solder joints or missing solder joints.

[0131] This application also provides a battery string, which is prepared by the above-described battery string preparation method.

[0132] A battery string may include multiple battery cells 200, which are connected in series or parallel by welding with solder ribbons 400. The electrode structure of the battery cell 200 has solder blocks 500, each solder block 500 including at least two solder sub-blocks 510 spaced apart along a first direction. The solder ribbons 400 are laid on the surface of the battery cell 200 along a second direction, and the solder ribbons 400 are in contact with each solder sub-block 510, forming two or more support points. This can effectively reduce the probability of the solder ribbons 400 slipping and reduce the offset of the solder ribbons 400. The arrangement of at least two spaced solder sub-blocks 510 not only allows the solder ribbons 400 to be firmly fixed on the solder blocks 500, but also reduces the amount of solder used in the area between the solder sub-blocks 510, effectively reducing manufacturing costs, reducing the offset of the solder ribbons 400, reducing the probability of cold solder joints or missing solder joints, and helping to improve product yield and overall power generation performance.

[0133] According to the battery string provided in the embodiments of this application, by preparing solder blocks 500 on the battery cell 200, each solder block 500 includes at least two solder sub-blocks 510 arranged at intervals along a first direction, and laying the solder ribbon 400 on the surface of the battery cell 200 along a second direction, each solder sub-block 510 forms a support point for the solder ribbon 400 and supports the solder ribbon 400 along the first direction, the offset of the solder ribbon 400 can be reduced, the probability of cold solder or missing solder is reduced, and it helps to improve product yield and overall power generation performance.

[0134] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0135] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0136] In the description of this application, "first feature" and "second feature" may include one or more of the features.

[0137] In the description of this application, "multiple" means two or more.

[0138] In the description of this application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features being in contact through another feature between them.

[0139] In the description of this application, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0140] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0141] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a battery string, characterized in that, include: A battery cell is provided, wherein the surface of the battery cell is provided with an electrode structure; Solder blocks are prepared on the electrode structure of the battery cell, each solder block comprising at least two solder sub-blocks spaced apart along a first direction; The solder ribbon is laid on the surface of the battery cell along the second direction. The solder ribbon is placed on the solder block and in contact with the at least two solder sub-blocks. The first direction and the second direction are perpendicular to each other and are both parallel to the plane where the battery cell is located. The solder strips are welded to the solder block to connect different battery cells to form a battery string; The at least two solder sub-blocks include two end solder sub-blocks located at both ends of the solder block. The first ends of the two end solder sub-blocks are close to each other, and the second ends of the two end solder sub-blocks are far apart from each other. The size of the end solder sub-blocks along the second direction gradually decreases from the first end to the second end.

2. The method for preparing a battery string according to claim 1, characterized in that, The process of fabricating solder blocks on the electrode structure of the battery cell includes: Solder is printed on the electrode structure according to the solder printing pattern; The solder block is obtained by performing a curing process. The solder printing pattern includes at least two sub-block printing patterns arranged at intervals along the first direction, the at least two sub-block printing patterns being used to form the at least two solder sub-blocks.

3. The method for preparing a battery string according to claim 2, characterized in that, The printed graphics of the sub-blocks can be circular, triangular, quadrilateral, or irregular in shape.

4. The method for preparing a battery string according to claim 1, characterized in that, The end solder sub-block is triangular in shape in the projection area of ​​the battery cell, with the first end corresponding to the base of the triangle and the second end corresponding to the apex of the triangle.

5. The method for preparing a battery string according to claim 1, characterized in that, The dimension of the end solder sub-block along the first direction is d1, the dimension of the first end along the second direction is L1, and the distance between the first ends of the two end solder sub-blocks is d2. When the solder block is located in the fine grid of the electrode structure, the following conditions are met: 1 / 3W≤d1≤2 / 3W, 1 / 3W≤d2≤2 / 3W, 1 / 2W≤L1≤2W, where W is the dimension of the solder strip along the first direction.

6. The method for preparing a battery string according to claim 1, characterized in that, The dimension of the end solder sub-block along the first direction is d1, the dimension of the first end along the second direction is L1, and the distance between the first ends of the two end solder sub-blocks is d2. When the solder block is located on the pad of the electrode structure, the following conditions are met: 1 / 2W≤d1≤3 / 2W, 1 / 3W≤d2≤1W, W≤L1≤2W, where W is the dimension of the solder strip along the first direction.

7. The method for preparing a battery string according to any one of claims 1-6, characterized in that, The size of the solder block located at the fine grid of the electrode structure is smaller than the size of the solder block located at the pad of the electrode structure.

8. The method for preparing a battery string according to any one of claims 1-6, characterized in that, After the solder strip and the solder block are soldered, the projection area of ​​the solder block on the battery cell is located within the projection area of ​​the solder strip on the battery cell.

9. The method for preparing a battery string according to any one of claims 1-6, characterized in that, The cross-section of the welding strip is circular, triangular, or quadrilateral.

10. A battery string, characterized in that, The battery string is prepared by the method described in any one of claims 1-9.

Images