Preparation method of battery string and battery string

Abstract

The invention discloses a preparation method of a battery string and the battery string, and belongs to the field of photovoltaic technology. The preparation method of the battery string comprises the following steps: providing a battery piece, wherein the surface of the battery piece is provided with an electrode structure; preparing solder blocks on the electrode structure of the battery piece, wherein each solder block comprises at least two solder sub-blocks which are arranged at intervals along a first direction; a welding strip is laid on the surface of the battery piece in the second direction, the welding strip is placed on the welding flux block and makes contact with the at least two welding flux sub-blocks, and the first direction and the second direction are perpendicular and both parallel to the plane where the battery piece is located; and welding the solder strip and the solder block, and connecting different battery pieces to form a battery string. According to the method, the solder strip is supported by the solder block, so that the deviation of the solder strip can be reduced, the occurrence probability of pseudo soldering or solder skips is reduced, and the product yield and the overall power generation performance can be improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a method for preparing a battery string and a battery string. Background Art

[0002] Solar cell technology, as a key solution for sustainable clean energy, has garnered significant attention in recent years. During module production, multiple cells are typically joined together using ribbons to form a string, followed by assembly and lamination. During the welding process, a pre-applied soldering material is often applied to the cells to strengthen the connection between the ribbon and the cells. This material can easily cause the ribbon to shift, potentially leading to cold or leaky solder joints, reducing product yield and impacting the overall power generation performance of the module. Summary of the Invention

[0003] This application aims to solve 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 the deviation of the welding ribbon, reduce the probability of cold or leaky welding, and help improve product yield and overall power generation performance.

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

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

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

[0007] Laying a solder ribbon on the surface of the cell along a second direction, the solder ribbon being placed on the solder block and in contact with the at least two solder sub-blocks, wherein the first direction and the second direction are perpendicular and parallel to the plane where the cell is located;

[0008] The soldering ribbons are soldered to the solder blocks to connect the different battery cells to form a battery string.

[0009] According to the preparation method of the battery string of the present application, solder blocks are prepared on the battery cells, each solder block includes at least two solder sub-blocks arranged at intervals along the first direction, and the solder strip is laid on the surface of the battery cell along the second direction. Each solder sub-block forms a support point for the solder strip, which supports the solder strip along the first direction. This can reduce the deviation of the solder strip and the probability of cold solder joints or leaking solder joints, which helps to improve product yield and overall power generation performance.

[0010] According to one embodiment of the present application, the step of preparing a solder bump on the electrode structure of the battery cell includes:

[0011] printing solder on the electrode structure according to a solder printing pattern;

[0012] Performing a curing process to obtain the solder block;

[0013] The solder printing pattern includes at least two sub-block printing patterns spaced apart along the first direction, and the at least two sub-block printing patterns are used to form the at least two solder sub-blocks.

[0014] According to one embodiment of the present application, the sub-block printed pattern is circular, triangular, quadrilateral or irregular.

[0015] According to one embodiment of the present 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 away 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.

[0016] According to one embodiment of the present application, the end solder sub-block is in the shape of a triangle in the projection area of ​​the battery cell, the first end corresponds to the base of the triangle, and the second end corresponds to the vertex of the triangle.

[0017] According to one embodiment of the present 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 two end solder sub-blocks is d2;

[0018] When the solder block is located at the fine grid of the electrode structure, 1 / 3W≤d1≤2 / 3W, 1 / 3W≤d2≤2 / 3W, and 1 / 2W≤L1≤2W are satisfied, where W is the size of the solder strip along the first direction.

[0019] According to one embodiment of the present 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 two end solder sub-blocks is d2;

[0020] When the solder block is located on the pad of the electrode structure, 1 / 2W≤d1≤3 / 2W, 1 / 3W≤d2≤1W, and W≤L1≤2W are satisfied, where W is the size of the solder strip along the first direction.

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

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

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

[0024] In a second aspect, the present application provides a battery string prepared by the battery string preparation method described in the first aspect above.

[0025] According to the battery string of the present application, solder blocks are prepared on the battery cells, each solder block includes at least two solder sub-blocks arranged at intervals along a first direction, and the solder strip is laid on the surface of the battery cell along a second direction. Each solder sub-block forms a support point for the solder strip, which supports the solder strip along the first direction. This can reduce the deviation of the solder strip and the probability of cold solder joints or leaking solder joints, thereby helping to improve product yield and overall power generation performance.

[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0028] Figure 1 1 is a flow chart of a method for preparing a battery string provided in an embodiment of the present application;

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

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

[0031] Figure 4 This is one of the schematic diagrams of the embodiment of the present application showing the soldering ribbon laid on the surface of the solar cell;

[0032] Figure 5 This is the second schematic diagram of the embodiment of the present application showing the soldering ribbon laid on the surface of the solar cell;

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

[0034] Figure 7 This is the second structural diagram of the solder block provided in the embodiment of the present application;

[0035] Figure 8is a schematic diagram of a solder block located on a fine grid provided in an embodiment of the present application;

[0036] Figure 9 is a schematic diagram of a solder block located on a pad provided by an embodiment of the present application;

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

[0038] Reference numerals:

[0039] Cell 200, fine grid 310, main grid 320, pad 330,

[0040] Solder ribbon 400 , solder block 500 , solder sub-block 510 , and insulating glue 600 . DETAILED DESCRIPTION

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

[0042] Reference below Figures 1-10 A method for preparing a battery string and a battery string according to an embodiment of the present application are described.

[0043] like Figure 1 As shown, the method for preparing a battery string according to an embodiment of the present application includes step 110 and step 140 .

[0044] Step 110: Provide a battery cell 200.

[0045] In this step, an electrode structure is provided on the surface of the provided battery cell 200. The electrode structure may include gate lines, pads 330 (PADs) and other structures.

[0046] Take the battery cell 200 as an example of a back contact battery.

[0047] A plurality of battery cells 200 are provided, and a plurality of fine grids 310 are provided on the back contact battery surface without a main grid 320 . The fine grids 310 with opposite conductive polarities are alternately arranged in sequence to collect the current on the battery cell 200 .

[0048] For a back-contact battery with a main grid 320, a plurality of fine grids 310 and a plurality of main grids 320 are provided on its surface. The fine grids 310 with opposite conductive polarities are alternately arranged in sequence to collect the current on the battery cell 200. The main grids 320 with opposite conductive polarities are also alternately arranged in sequence. The main grid 320 intersects with and is electrically connected to the fine grids 310 with the same conductive polarity to summarize and derive the current collected by the fine grids 310.

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

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

[0051] It can be understood 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 battery cell 200 . The solder blocks 500 are located on the electrode structure of the battery cell 200 . Each solder block 500 includes two or more solder sub-blocks 510 spaced apart along a first direction.

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

[0054] In actual implementation, when the solder block 500 includes two or more solder sub-blocks 510 spaced apart along the first direction, the solder blocks 500 are 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 a plurality of solder blocks 500 may be prepared on the battery cell 200 , and the position, quantity, and size of the solder blocks 500 are related to the type and distribution of the electrode structures on the battery cell 200 .

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

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

[0058] In this step, the solder ribbon 400 is placed on the solder bump 500 and contacts at least two solder sub-bumps 510 .

[0059] The first direction and the second direction are perpendicular and parallel to the plane of the battery cell 200. That is, the first direction can be any direction parallel to the plane of the battery cell 200, and the second direction can be any direction parallel to the plane of the battery cell 200 and perpendicular to the first direction. It should be noted that "perpendicular" here includes not only an absolute 90-degree perpendicularity, but also other approximately perpendicular conditions close to 90 degrees.

[0060] For example, Figure 8As shown, the first direction is the left-right direction, and the second direction is the up-down direction. The solder ribbon 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 ribbon 400, supporting the solder ribbon 400 from both sides, effectively reducing the probability of the solder ribbon 400 sliding to the left or right.

[0061] It can be 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 soldering ribbon 400 is laid on the surface of the battery cell 200 along the second direction, the soldering ribbon 400 contacts the solder block 500 on the surface of the battery cell 200, and the soldering ribbon 400 contacts at least two solder sub-blocks 510 of each solder block 500. Each solder sub-block 510 forms a support point for the soldering ribbon 400, supporting the soldering ribbon 400 along the first direction, which can effectively reduce the probability of the soldering ribbon 400 sliding along the first direction and reduce the offset of the soldering ribbon 400.

[0063] In the related art, wet solder paste (soldering material) is printed on the battery surface during the soldering process, and then semi-cured by a high-temperature process. During the curing process, the solder paste forms a curved surface due to the wetting principle, such as Figure 2 As shown, the solder paste B1 is located on the surface of the battery C1. When the solder ribbon A1 with a rectangular cross section is placed on the solder paste B1, the solder ribbon A1 is easily offset. Figure 3 As shown, the solder paste B1 is located on the surface of the battery C1. When the solder ribbon A2 with a circular cross-section is placed on the solder paste B1, the solder ribbon A2 is easily offset, and cold solder joints or leaking solder joints are likely to occur after soldering.

[0064] In the embodiment of the present application, a solder block 500 is prepared on the battery cell 200. Each solder block 500 includes at least two solder sub-blocks 510 spaced apart along the first direction D1. The solder ribbon 400 is laid on the surface of the battery cell 200 along the second direction. Figure 4 As shown, when the solder ribbon 400 with a rectangular cross section is placed on the solder block 500, the solder ribbon 400 contacts at least two solder sub-blocks 510, forming at least two support points, which can provide a stable support for the solder ribbon 400 whose contact surface with the solder block 500 is a plane, as shown in FIG. Figure 5As shown, when the solder ribbon 400 with a circular cross-section is placed on the solder block 500, the solder ribbon 400 contacts at least two solder sub-blocks 510 to form at least two support points, which can also provide stable support for the solder ribbon 400 whose contact surface with the solder block 500 is a curved surface. The solder ribbon 400 is placed on at least two solder sub-blocks 510 spaced apart along the first direction, which can effectively reduce the probability of the solder ribbon 400 slipping and reduce the offset of the solder ribbon 400, which helps to improve the welding effect of subsequent processes.

[0065] It can be understood that the soldering ribbon 400 is laid on the battery cell 200 along the second direction, and a plurality of soldering points, i.e., a plurality of points in contact with the solder block 500, can be provided on one soldering ribbon 400. The battery cell 200 can have a plurality of solder blocks 500 arranged at intervals along the second direction.

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

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

[0068] It should be noted that when the soldering ribbon 400 and the solder block 500 are soldered, the solder block 500 will move toward the position of the soldering ribbon 400. When the soldering ribbon 400 is laid on the battery cell 200, the axis of the soldering ribbon 400 in the length direction can be aligned with the midpoint of the solder block 500. For the solder block 500 including two solder sub-blocks 510, the soldering ribbon 400 is placed centrally between the two solder sub-blocks 510, and the solder sub-blocks 510 on both sides of the axis of the soldering ribbon 400 are evenly distributed, which helps to improve the subsequent welding effect.

[0069] In the related art, in the case where the welding strips are prone to deviation, a fixed film layer is laminated to reduce the deviation of the positive and negative electrode welding strips during the process of the main grid back contact battery assembly. However, the addition of a film layer will increase the cost and the complexity of the preparation process, and the lamination process is also prone to cause the solder to fall off, and there is still a high probability of cold soldering or welding leakage.

[0070] In the embodiment of the present application, by improving the shape of the solder block 500, a solder block 500 consisting of at least two solder sub-blocks 510 arranged at intervals along a first direction is prepared on the battery cell 200, and the solder ribbon 400 is placed on the solder block 500. The solder ribbon 400 contacts the at least two solder sub-blocks 510 to form at least two support points, which can effectively reduce the probability of the solder ribbon 400 slipping and reduce the offset of the solder ribbon 400. Moreover, the at least two solder sub-blocks 510 spaced apart are provided, which not only allows the solder ribbon 400 to be firmly placed on the solder block 500, but also reduces the amount of solder used in the area between the solder sub-blocks 510, effectively reduces the preparation cost, reduces the offset of the solder ribbon 400, and reduces the probability of cold solder joints or leaks, thereby helping to improve product yield and overall power generation performance.

[0071] According to the preparation method of the battery string provided in the embodiment of the present application, a solder block 500 is prepared 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 the solder strip 400 is laid on the surface of the battery cell 200 along a second direction. Each solder sub-block 510 forms a support point for the solder strip 400, supporting the solder strip 400 along the first direction, which can reduce the offset of the solder strip 400 and reduce the probability of cold solder joints or leaking solder joints, thereby helping to improve product yield and overall power generation performance.

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

[0073] printing solder on the electrode structure according to the solder printing pattern;

[0074] Performing a curing process to obtain a solder block 500;

[0075] The solder printing pattern includes at least two sub-block printing patterns spaced apart along the first direction, and the at least two sub-block printing patterns are used to form at least two solder sub-blocks 510 .

[0076] In this embodiment, solder is printed on the electrode structure of the battery cell 200 using a solder printing pattern. One solder printing pattern may correspond to printing 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] For example, the solder is tin and the 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 battery cell 200, and the solder paste is solidified through a high-temperature process to prevent the wet solder paste from being touched and dropped by the assembly line during the process. During the solidification process, the solder paste forms a curved surface on the battery cell 200 due to the wetting principle. The solder ribbon 400 is laid on the surface of the battery cell 200 along the second direction, and the two solder sub-blocks 510 arranged opposite to each other along the first direction are located 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 joints or leaking solder joints, and help improve product yield and overall power generation performance.

[0079] In actual implementation, the solder is printed according to the solder printing pattern, and the surface of the solder facing away from the battery cell 200 is a plane. After the solidification process, the surface of the solder facing away from the battery cell 200 forms a curved surface.

[0080] It should be noted that during the curing process, the solder corresponding to each solder sub-block 510 is wetted separately, and 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 contacts at least two solder sub-blocks 510. Each solder sub-block 510 forms a support point for the solder ribbon 400, reducing the deviation of the solder ribbon 400. After welding, at least two solder sub-blocks 510 can be melted into one point, or they can still remain separated.

[0081] In some embodiments, the sub-block printed pattern is circular, triangular, quadrilateral or irregular in shape.

[0082] In this embodiment, according to the type and distribution of the electrode structure on the battery cell 200 , a sub-block printing pattern of a circular, triangular, quadrilateral or irregular-shaped solder printing pattern can be selected to print solder on the battery cell 200 .

[0083] It is understandable that the solder blocks 500 at different positions 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 sub-block printed pattern can be circular, triangular, quadrilateral or irregular. After printing the solder 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 solidification, the solder faces 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] Among them, the quadrilateral can be a rhombus, rectangle, square and other shapes, and the irregular shape can refer to a polygon 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 solder printing pattern of the double triangle pattern, and after solidification, the following is formed: Figure 6 As shown in the solder blocks 500 , each solder block 500 includes two or more solder sub-blocks 510 spaced apart along a first direction. The projection of each solder sub-block 510 on the battery cell 200 maintains a triangular shape.

[0087] It can be 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 away 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 more than two solder sub-blocks 510, in the solder block 500, the end solder sub-blocks located at both ends have a first end and a second end, and the shape of the solder sub-block 510 located in the middle 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 the first direction, the first ends of the two end solder sub-blocks are close to each other and spaced apart, and the second ends of the two end solder sub-blocks are far away from each other, and each end solder sub-block presents a shape in which the size along the second direction gradually decreases from the first end to the second end.

[0091] In actual implementation, when soldering is performed, the solder block 500 will move toward the position of the soldering strip 400, and the soldering strip 400 can be centered between the two end solder sub-blocks. The two end solder sub-blocks are close to each other and the first end with a relatively larger size can provide support for the soldering strip 400, so that the soldering strip 400 and the first end form a stable support point.

[0092] In this embodiment, the size of the end solder sub-block along the second direction gradually decreases from the first end to the second end. Compared with the rectangular solder with 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 with 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 material used to prepare the solder block 500 may include acidic flux. During the welding process, the flux may not be completely volatilized, resulting in residue. The molecular bonds of the acidic flux may be destroyed under light, causing the flux to corrode the battery cell 200.

[0094] In this embodiment, the second ends that are far away from each other are distributed on both sides of the soldering strip 400. The second ends are relatively small in size, and the portion of the solder block 500 exposed from the soldering strip 400 is small, which is convenient for retracting to the bottom of the soldering strip 400 during welding. That is, after welding is completed, the soldering strip 400 can cover the solder block 500 and reduce the corrosion caused by the exposure of the solder block 500.

[0095] In some embodiments, the projection area of ​​the end solder sub-block on the battery cell 200 is in the shape of a triangle, with the first end corresponding to the base of the triangle and the second end corresponding to the vertex of the triangle.

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

[0097] like Figure 6 As shown, under the same amount of solder used, the end solder sub-block is triangular in the projected area of ​​the battery cell 200, which can increase the overall printing width of the solder block 500 in the first direction D1. The solder strip 400 is laid on the battery cell 200 along the second direction D2. The solder strip 400 can be centered between the two triangles. The solder strip 400 contacts both end solder sub-blocks. The bottom edges of the two triangles provide a firm support for the solder strip 400. The top corners of the two triangles use less solder, which is convenient for retracting to the bottom of the solder strip 400 during welding, thereby reducing corrosion of the battery cell 200.

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

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

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

[0101] For example, the first direction D1 is the horizontal direction and the second direction D2 is the vertical direction.

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

[0103] In some embodiments, when the solder bump 500 is located on the fine grid 310 of the electrode structure, 1 / 3W≤d1≤2 / 3W, 1 / 3W≤d2≤2 / 3W, and 1 / 2W≤L1≤2W are satisfied, where W is the size of the solder strip 400 along the first direction.

[0104] It can be understood that W is the size of the welding ribbon 400 along the first direction. For a welding ribbon 400 with a circular cross-section, W may be the diameter of the welding ribbon 400 . For a welding ribbon 400 with a rectangular cross-section, W may be the width of the welding ribbon 400 .

[0105] In this embodiment, for the solder block 500 located at 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 / 3-2 / 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 1-2 times the width (or diameter) of the solder strip 400, which is convenient for placing the solder strip 400. At the same time, the solder block 500 will not exceed the solder strip 400 too much in the first direction, which can control printing costs and reduce corrosion (for acidic flux scenarios).

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

[0107] It is understandable that the pad 330 is a metallized area used to achieve electrical connection and collect gate line current. During component packaging, the pad 330 is the location where the battery cell 200 is welded to the welding ribbon 400 to achieve a firm connection between the battery 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 / 2-3 / 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 / 3-1 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 / 3-4 times the width (or diameter) of the solder strip 400, and at the same time, the maximum longitudinal length of the end solder sub-block can be 1-2 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. On the premise of reducing the risk of gate line breakage, the larger size of the solder block 500 in the first direction and the second direction can effectively enhance the welding reliability and facilitate the placement of the solder strip 400.

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

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

[0111] For example, the solder block 500 includes two end solder sub-blocks, and the projection area of ​​the end solder sub-blocks on the battery cell 200 is a triangle.

[0112] L1 is the maximum longitudinal length of the end solder sub-block, that is, the length of the base of the triangle, d1 is the lateral length of the end solder sub-block, that is, the height from the base of the triangle to the vertex, d2 is the lateral spacing between the two end solder sub-blocks, that is, the spacing between the two bases of the triangle, and W is the size of the solder strip 400 along the first direction.

[0113] like Figure 8 As shown, the fine grid 310 on the battery cell 200 extends along the first direction D1, and multiple fine grids 310 are arranged at intervals along the second direction D2. The solder blocks 500 are arranged on the fine grids 310. Each solder block 500 includes an end solder sub-block that is triangular in the projection area of ​​the battery cell 200. The solder ribbon 400 is laid on the battery cell 200 along the second direction D2. The size of the solder block 500 meets the following requirements: 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 battery cell 200 extends along the first direction D1, and multiple fine grids 310 are arranged at intervals along the second direction D2. The main grid 320 extends along the first direction, and the solder block 500 is arranged on the pad 330 on the main grid 320. Each solder block 500 includes an end solder sub-block that is triangular in the projection area of ​​the battery cell 200. The solder ribbon 400 is laid on the battery cell 200 along the second direction D2. The size of the solder block 500 meets the following requirements: 1 / 2W≤d1≤3 / 2W, 1 / 3W≤d2≤1W, and W≤L1≤2W.

[0115] In this embodiment, d2+2d1 of the solder block 500 at the fine grid 310 can be smaller than d2+2d1 of the solder block 500 at the pad 330, and L1 of the solder block 500 at the fine grid 310 can be smaller than L1 of the solder block 500 at the pad 330, that is, the size of the solder block 500 located at the fine grid 310 is slightly smaller than the size of the solder block 500 located at the pad 330, and the size of the fine grid 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 grid 310 being welded off.

[0116] In actual implementation, the size of the end solder sub-block is adjusted according to the size of the solder ribbon 400 along the first direction, and can be applied to batteries with a busbar 320 (with solder pads 330) or without a busbar 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, and the solder is printed on the electrode structure according to the solder printing pattern. After curing treatment, two end solder sub-blocks of the required size are obtained.

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

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

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

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

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

[0123] The quadrilateral may be a rhombus, a rectangle, a square or the like.

[0124] In this embodiment, the solder ribbon 400 is laid on the surface of the battery cell 200 along the second direction, and 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 circular, triangular, quadrilateral or other cross-section, effectively reducing the probability of the solder ribbon 400 slipping and reducing the offset of the solder ribbon 400.

[0125] For example, Figure 4 As shown, when the solder ribbon 400 with a rectangular cross-section is placed on the solder block 500, the solder ribbon 400 contacts both solder sub-blocks 510 to form two support points, which can provide a stable support for the solder ribbon 400 whose contact surface with the solder block 500 is a plane.

[0126] For example, Figure 5 As shown, when the solder ribbon 400 with a circular cross-section is placed on the solder block 500, the solder ribbon 400 contacts both solder sub-blocks 510 to form two support points, which can also provide a stable support for the solder ribbon 400 whose contact surface with the solder block 500 is a curved surface.

[0127] It can be understood that the preparation method of the battery string provided in the embodiment of the present application can be applied to various types of batteries that form a battery string by connecting the battery cell 200 through the solder ribbon 400 and the solder block 500, such as back contact battery (BC), passivated emitter and rear cell (PERC), tunnel oxide passivated contact battery (TOPCon), intrinsic thin film heterojunction battery (HJT) and other types.

[0128] Among them, the back-contact battery is a type of battery that places all positive and negative electrodes on the back, reducing the obstruction of sunlight by the electrodes placed on the front and improving the photoelectric conversion efficiency of the battery.

[0129] In actual implementation, for a back contact battery, an insulating glue 600 may be printed on the heterogeneous 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 glue 600, the overlapping short circuit of the battery cell 200 can be improved. The main grid 320 forms a height difference with the top of the insulating glue 600. The welding strip 400 cannot directly contact the silver paste of the main grid 320, which may cause cold soldering.

[0130] A solder block 500 is printed at the main grid 320 of the battery cell 200 so that the top of the solder block 500 is higher than the top of the insulating glue 600. The solder block 500 realizes the connection between the solder strip 400 and the battery 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, supporting the solder strip 400 from both sides of the solder strip 400, which can reduce the offset of the solder strip 400 and reduce the probability of cold solder joints or leaking solder joints.

[0131] An embodiment of the present application further provides a battery string, which is prepared by the above-mentioned battery string preparation method.

[0132] The battery string may include multiple battery cells 200, and the multiple battery cells 200 are welded by welding ribbons 400 to form a series or parallel connection relationship. There is a solder block 500 on the electrode structure of the battery cell 200, and each solder block 500 includes at least two solder sub-blocks 510 arranged at intervals along a first direction. The solder ribbon 400 is laid on the surface of the battery cell 200 along a second direction. The solder ribbon 400 is in contact with each solder sub-block 510 to form two or more support points, which can effectively reduce the probability of the solder ribbon 400 slipping and reduce the offset of the solder ribbon 400. The at least two solder sub-blocks 510 spaced apart are set, which not only allows the solder ribbon 400 to be firmly prevented 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 preparation cost, reducing the offset of the solder ribbon 400, and reducing the probability of cold solder joints or leaks, which helps to improve product yield and overall power generation performance.

[0133] According to the battery string provided in the embodiment of the present application, a solder block 500 is prepared 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 the solder strip 400 is laid on the surface of the battery cell 200 along a second direction. Each solder sub-block 510 forms a support point for the solder strip 400, supporting the solder strip 400 along the first direction, which can reduce the offset of the solder strip 400 and reduce the probability of cold solder joints or leaking solder joints, thereby helping to improve product yield and overall power generation performance.

[0134] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0135] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "left", "right", etc., indicating the orientation or position relationship, are based on the orientation or position 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, be constructed and operated in a specific orientation. Therefore, they cannot be understood 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, “plurality” means two or more.

[0138] In the description of the present application, a first feature being “on” or “under” a second feature may include the first and second features being in direct contact with each other, or the first and second features being in contact with each other not directly but via another feature therebetween.

[0139] In the description of this application, a first feature “on”, “above” and “above” a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0140] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0141] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for preparing a battery string, characterized in that: include: Providing a battery cell, wherein an electrode structure is provided on a surface of the battery cell; preparing solder blocks on the electrode structure of the battery cell, each of the solder blocks comprising at least two solder sub-blocks spaced apart along a first direction; Laying a solder ribbon on the surface of the cell along a second direction, the solder ribbon being placed on the solder block and in contact with the at least two solder sub-blocks, wherein the first direction and the second direction are perpendicular and parallel to the plane where the cell is located; The soldering ribbons are soldered to the solder blocks to connect the different battery cells to form a battery string.

2. The method for preparing a battery string according to claim 1, wherein: The step of preparing a solder bump on the electrode structure of the battery cell comprises: printing solder on the electrode structure according to a solder printing pattern; Performing a curing process to obtain the solder block; The solder printing pattern includes at least two sub-block printing patterns spaced apart along the first direction, and the at least two sub-block printing patterns are used to form the at least two solder sub-blocks.

3. The method for preparing a battery string according to claim 2, wherein: The sub-block printed graphics are circular, triangular, quadrilateral or irregular shapes.

4. The method for preparing a battery string according to claim 1, wherein: 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 away 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.

5. The method for preparing a battery string according to claim 4, characterized in that: The end solder sub-block is in the shape of a triangle in the projection area of ​​the battery cell, the first end corresponds to the base of the triangle, and the second end corresponds to the vertex of the triangle.

6. The method for preparing a battery string according to claim 4, 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 two end solder sub-blocks is d2; When the solder block is located at the fine grid of the electrode structure, 1 / 3W≤d1≤2 / 3W, 1 / 3W≤d2≤2 / 3W, and 1 / 2W≤L1≤2W are satisfied, where W is the size of the solder strip along the first direction.

7. The method for preparing a battery string according to claim 4, 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 two end solder sub-blocks is d2; When the solder block is located on the pad of the electrode structure, 1 / 2W≤d1≤3 / 2W, 1 / 3W≤d2≤1W, and W≤L1≤2W are satisfied, where W is the size of the solder strip along the first direction.

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

9. The method for preparing a battery string according to any one of claims 1 to 7, characterized in that: After the soldering ribbon and the solder block are soldered, a projection area of ​​the solder block on the battery cell is located within a projection area of ​​the solder ribbon on the battery cell.

10. The method for preparing a battery string according to any one of claims 1 to 7, characterized in that: The cross section of the welding strip is circular, triangular or quadrilateral.

11. A battery string, characterized in that: The battery string is prepared by the method for preparing the battery string according to any one of claims 1 to 10.

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