A main grid-free back contact battery, battery module and preparation method

Abstract

The embodiment of the present invention provides a busbar-free back contact battery, a battery module and a preparation method, which relate to the technical field of back contact batteries. The busbar-free back contact battery includes a battery cell, a plurality of first fine grid lines for collecting a first polarity, and a plurality of second fine grid lines for collecting a second polarity, wherein the plurality of first fine grid lines and the plurality of second fine grid lines are arranged alternately in sequence along the width direction of the battery cell, the lengths of the first fine grid lines and the second fine grid lines are substantially the same, and there is no need to set a fold line or a busbar, and the first fine grid lines and the second fine grid lines both have a disconnection area, which is used to cooperate with a welding strip, and the width range of the disconnection area is 1mm-5mm, thereby reserving sufficient tolerance for the installation of the welding strip to avoid the welding strip from contacting the first fine grid line or the second fine grid line and thus causing a short circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of back contact batteries, and in particular to a busbar-free back contact battery, a battery module and a preparation method thereof. Background Art

[0002] Back-contact solar cells are cells that place both the emitter and base contact electrodes on the back side of the cell (non-light-receiving side). The light-receiving side of the cell is not blocked by any metal electrode, which effectively increases the short-circuit current of the cell. At the same time, the back side can allow for wider metal grid lines to reduce series resistance and thus increase the fill factor. Moreover, this type of cell with no obstruction on the front side not only has high conversion efficiency, but also looks more beautiful. At the same time, the components with full back electrodes are easier to assemble. For back-contact solar cells, multiple main grids can shorten the transmission length of the current on the metal fine grid electrode. According to the power loss (P=I 2 R) calculation, the increase in the number of main grids is equivalent to dividing the battery into more unit blocks, and the current of each unit block is smaller. At the same time, the transmission distance of the current on the fine grid can be reduced, thereby reducing the conductivity requirements of the fine grid electrode, and then reducing the amount of silver paste and the cost of metal electrodes. However, the positive and negative metal electrodes of the back contact battery are both on the back of the battery. If the main grid is set on the edges of both sides of the battery, the stress of the welding belt after the module string welding is made is very large, which can easily cause hidden cracks or fragments in the battery, thereby affecting the yield and reliability of the module.

[0003] The back contact battery in the prior art has technical problems such as uneven length of fine grids and severe deformation of the battery after welding. Summary of the invention

[0004] The present invention provides a main grid-free back contact battery, a battery module and a preparation method, which can ensure the consistency of the length of the fine grid and improve the battery deformation problem.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] An embodiment of the present invention provides a busbar-free back contact battery, comprising a battery cell, a plurality of first fine grid lines for collecting a first polarity, and a plurality of second fine grid lines for collecting a second polarity, wherein the plurality of first fine grid lines and the plurality of second fine grid lines are alternately arranged in sequence along the width direction of the battery cell, and the first fine grid lines and the second fine grid lines both have a disconnection area, and the disconnection area is used to cooperate with a welding strip, wherein the width range of the disconnection area is 1 mm-5 mm;

[0007] A plurality of welding strip connection blocks are provided on the first fine grid line and the second fine grid line, and the plurality of welding strip connection blocks are respectively arranged at both ends and the middle of the battery cell, wherein the spacing between the welding strip connection block located at the end of the battery cell and the adjacent welding strip connection block ranges from 6mm to 16mm, the spacing between two adjacent welding strip connection blocks located in the middle of the battery cell ranges from 6mm to 16mm, and the difference between the spacing between two adjacent welding strip connection blocks located in the middle of the battery cell and the spacing between the welding strip connection block located at the end of the battery cell and the adjacent welding strip connection block is less than 3mm;

[0008] In the width direction of the battery cell, an insulating block is provided between two adjacent welding strip connecting blocks, the length of the insulating block ranges from 2 mm to 5 mm, and the length of the insulating block is 2.5 times to 10 times the width of the welding strip.

[0009] Optionally, the disconnection area includes a first disconnection area and a second disconnection area, the first disconnection area is located on the first fine gate line, all the first disconnection areas are located on the same straight line, the second disconnection area is located on the second fine gate line, all the second disconnection areas are located on the same straight line, and the first disconnection area and the second disconnection area are staggered.

[0010] Optionally, the width of the first fine gate line and / or the second fine gate line is in the range of 10um-100um.

[0011] Optionally, the thickness of the first fine gate line and / or the second fine gate line is in the range of 5um-20um.

[0012] Optionally, a distance between an end of the first fine grid line and / or the second fine grid line and an edge of the battery cell is in a range of 1 mm to 4 mm.

[0013] Optionally, the length of the soldering ribbon connection block ranges from 100um to 500um, and the width of the soldering ribbon connection block ranges from 50um to 4mm.

[0014] Optionally, a spacing between the welding ribbon connection block at the end of the battery cell and the edge of the battery cell is in a range of 0.6 mm to 3 mm.

[0015] An embodiment of the present invention further provides a battery module, comprising a battery string, wherein the battery string comprises a welding strip and a plurality of main grid-free back contact batteries, wherein the polarities of two adjacent battery sheets are opposite, the welding strip is overlapped on the welding strip connection block and the insulating block of the two adjacent battery sheets, and the width of the welding strip is in the range of 0.3 mm to 2 mm;

[0016] The welding strip includes a first welding strip and a second welding strip, the first welding strip is overlapped at the middle of the battery cell, the second welding strip is overlapped at both ends of the battery cell, and the cross-sectional area of ​​the first welding strip is 2 to 6 times the cross-sectional area of ​​the second welding strip.

[0017] Optionally, the battery module further includes an adhesive film layer, and the adhesive film layer is arranged on the bottom of the battery cell and the surface of the welding strip.

[0018] An embodiment of the present invention further provides a method for manufacturing a battery module, wherein the battery module is manufactured, and the method for manufacturing the battery module comprises:

[0019] Laying the welding ribbon on two adjacent battery strings so that the welding ribbon covers the welding ribbon connecting block and the insulating block;

[0020] A film layer is attached to the surface of the battery cell on one side of which the welding tape is overlapped, and the film layer is heated to connect the welding tape and the battery cell, and the heating temperature ranges from 50°C to 100°C.

[0021] The beneficial effects of the busbar-free back contact battery, battery module and preparation method of the embodiments of the present invention include, for example:

[0022] The main grid-free back contact battery includes a battery cell, a plurality of first fine grid lines for collecting a first polarity, and a plurality of second fine grid lines for collecting a second polarity. The plurality of first fine grid lines and the plurality of second fine grid lines are alternately arranged in sequence along the width direction of the battery cell. The lengths of the first fine grid lines and the second fine grid lines are basically the same, and there is no need to set a fold line or a main grid. The first fine grid lines and the second fine grid lines both have a disconnection area, and the disconnection area is used to cooperate with the welding strip. The width range of the disconnection area is 1mm-5mm, thereby reserving sufficient tolerance for the installation of the welding strip to avoid the welding strip and the first fine grid line or the second fine grid line from contacting and causing a short circuit; the first fine grid line and the second fine grid line are both provided with a plurality of welding strip connecting blocks, and the plurality of welding strip connecting blocks are respectively arranged at both ends and the middle of the battery cell, and the welding strip connecting blocks located at the ends of the battery cell The spacing between the block and the adjacent welding strip connection block is in the range of 6mm-16mm, the spacing between the two adjacent welding strip connection blocks in the middle of the battery cell is in the range of 6mm-16mm, and the difference between the spacing between the two adjacent welding strip connection blocks in the middle of the battery cell and the spacing between the welding strip connection block at the end of the battery cell and the adjacent welding strip connection block is less than 3mm, so that the spacing between the two adjacent welding strip connection blocks can be closer to the maximum length of carrier transmission, so that the carriers can flow back to the welding strip as much as possible; in the width direction of the battery cell, an insulating block is provided between the two adjacent welding strip connection blocks, the length of the insulating block is in the range of 2mm-5mm, and the length of the insulating block is 2.5 times to 10 times the width of the welding strip, thereby reducing the stress of the welding strips on both sides of the battery. The overall process is simple, ensuring the consistency of the length of the fine grid and improving the problem of battery deformation.

[0023] The battery module includes a battery string, the battery string includes a welding strip and a plurality of main grid-free back contact batteries, the polarities of two adjacent battery cells are opposite, the welding strip is overlapped on the welding strip connection block and the insulating block of the two adjacent battery cells, and the width of the welding strip ranges from 0.3mm to 2mm; the welding strip includes a first welding strip and a second welding strip, the first welding strip is overlapped on the middle of the battery cell, and the second welding strip is overlapped on both ends of the battery cell, and the cross-sectional area of ​​the first welding strip is 2 to 6 times the cross-sectional area of ​​the second welding strip. When in use, the battery module can ensure that the length of the fine grid is consistent, improving the problem of battery deformation.

[0024] The manufacturing method of the battery module manufactures the battery module, and the manufacturing method of the battery module comprises: laying the welding strip on two adjacent battery strings so that the welding strip covers the welding strip connection block and the insulating block; attaching a film layer to the surface of the battery cell on one side of which the welding strip is overlapped, heating the film layer to connect the welding strip and the battery cell, and the heating temperature ranges from 50° C. to 100° C. The manufacturing method of the battery module is simple and convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic structural diagram of a busbar-free back contact battery from a first perspective provided in this embodiment;

[0027] Figure 2 A schematic structural diagram of a busbar-free back contact battery from a second viewing angle provided in this embodiment;

[0028] Figure 3 A schematic structural diagram of a battery module provided in this embodiment from a first perspective;

[0029] Figure 4 A schematic diagram of the structure of the battery module provided in this embodiment from a second viewing angle;

[0030] Figure 5 A schematic structural diagram of the battery module provided in this embodiment from a third perspective.

[0031] Icon: 10-battery cell; 20-first thin grid line; 30-second thin grid line; 101-first disconnection area; 102-second disconnection area; 40-welding strip connecting block; 50-insulating block; 100-main grid-free back contact battery; 200-welding strip; 210-first welding strip; 220-second welding strip; 300-adhesive film layer; 400-back adhesive film; 500-back plate; 600-front adhesive film; 700-front plate; 1000-battery module. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0035] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention 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, and therefore cannot be understood as a limitation on the present invention.

[0036] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0037] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0038] Back-contact solar cells are cells that place both the emitter and base contact electrodes on the back side of the cell (non-light-receiving side). The light-receiving side of the cell is not blocked by any metal electrode, which effectively increases the short-circuit current of the cell. At the same time, the back side can allow for wider metal grid lines to reduce series resistance and thus increase the fill factor. Moreover, this type of cell with no obstruction on the front side not only has high conversion efficiency, but also looks more beautiful. At the same time, the components with full back electrodes are easier to assemble. For back-contact solar cells, multiple main grids can shorten the transmission length of the current on the metal fine grid electrode. According to the power loss (P=I 2 R) calculation, the increase in the number of main grids is equivalent to dividing the battery into more unit blocks, and the current of each unit block is smaller. At the same time, the transmission distance of the current on the fine grid can be reduced, thereby reducing the conductivity requirements of the fine grid electrode, and then reducing the amount of silver paste and the cost of metal electrodes. However, the positive and negative metal electrodes of the back contact battery are both on the back of the battery. If the main grid is set on the edges of both sides of the battery, the stress of the welding belt after the module string welding is made is very large, which can easily cause hidden cracks or fragments in the battery, thereby affecting the yield and reliability of the module.

[0039] The back contact battery in the prior art has technical problems such as uneven length of fine grids and severe deformation of the battery after welding.

[0040] Please refer to Figure 1-Figure 5This embodiment provides a battery module 1000, which includes a battery string, the battery string includes a welding strip 200 and a plurality of main grid-free back contact batteries 100, the polarities of two adjacent battery cells 10 are opposite, and the welding strip 200 is overlapped on the welding strip connection block 40 and the insulating block 50 of the two adjacent battery cells 10. It can effectively improve the above-mentioned technical problems, ensure the consistency of the length of the fine grid, and improve the battery deformation problem.

[0041] Please refer to Figure 1-Figure 5 The busbar-free back contact battery 100 comprises a battery cell 10, a plurality of first fine grid lines 20 for collecting a first polarity, and a plurality of second fine grid lines 30 for collecting a second polarity, wherein the plurality of first fine grid lines 20 and the plurality of second fine grid lines 30 are alternately arranged in sequence along the width direction of the battery cell 10. Figure 1 The relative positions in FIG. 1 are described as follows. The first thin gate lines 20 and the second thin gate lines 30 are alternately arranged in sequence along the vertical direction.

[0042] The first fine grid line 20 and the second fine grid line 30 both have a disconnection area, and the disconnection area is used to cooperate with the welding strip 200. Specifically, the disconnection area includes a first disconnection area 101 and a second disconnection area 102. The first disconnection area 101 is located on the first fine grid line 20, and all the first disconnection areas 101 are located on the same straight line. The second disconnection area 102 is located on the second fine grid line 30, and all the second disconnection areas 102 are located on the same straight line. The first disconnection area 101 and the second disconnection area 102 are staggered. Among them, the first disconnection area 101 and the second disconnection area 102 are both located in the middle of the battery cell 10, and all the first disconnection areas 101 are arranged in a row, and all the second disconnection areas 102 are arranged in a row, so that Figure 1 To illustrate the relative positions in the figure, the spacing between the first fine grid line 20 and / or the second fine grid line 30 and the edge of the battery cell 10 is W1, and the spacing W1 between the end of the first fine grid line 20 and / or the second fine grid line 30 and the edge of the battery cell 10 is in the range of 1mm-4mm; the width of the disconnected area of ​​the first fine grid line 20 and / or the second fine grid line 30 in the middle of the battery cell 10 is W2, and the range of W2 is 1mm-5mm.

[0043] It should be noted that the width of the soldering strip 200 ranges from 0.3mm to 2mm, and there is a tolerance between the width of the soldering strip 200 and W1 and W2, so that the first disconnection area 101 and the second disconnection area 102 can completely accommodate the soldering strip 200, thereby preventing the soldering strip 200 from contacting the first fine grid line 20 or the second fine grid line 30 after being installed in the first disconnection area 101 and the second disconnection area 102, thereby causing a short circuit; at the same time, the values ​​of W1 and W2 should be as small as possible while ensuring that sufficient tolerance is reserved for the soldering strip 200, thereby reducing the transmission of carriers in the area without fine grids, thereby reducing power loss.

[0044] In this embodiment, the lengths of the first thin grid line 20 and the second thin grid line 30 are basically the same, and there is no need to set a fold line and a main grid. The welding strip 200 can be installed in the first disconnection area 101 and the second disconnection area 102, which reduces the consumption of metal electrode materials and reduces costs. At the same time, the setting without a main grid can avoid hidden cracks or breakages in the battery cell 10 during subsequent welding, thereby ensuring the yield and reliability of the battery module 1000 and making the process simpler.

[0045] In this embodiment, the first polarity and the second polarity are opposite polarities, and the first fine gate lines 20 and the second fine gate lines 30 are formed by printing, inkjet printing of silver paste or electroplating of copper.

[0046] In this embodiment, the width of the first fine gate line 20 and / or the second fine gate line 30 is in the range of 10 um-100 um, and the thickness of the first fine gate line 20 and / or the second fine gate line 30 is in the range of 5 um-20 um.

[0047] It should also be noted that a plurality of welding strip connection blocks 40 are disposed on the first fine grid line 20 and the second fine grid line 30. The plurality of welding strip connection blocks 40 are disposed at both ends and the middle of the battery cell 10, respectively. Figure 1 In the A region of the figure, the ribbon connection blocks 40 are arranged in two rows in the A region. The number of rows of the ribbon connection blocks 40 located in the middle of the battery cell 10 is between 2 and 20. The ribbon connection blocks 40 on the adjacent first fine grid lines 20 and the second fine grid lines 30 are staggered. Figure 1 The number of arrangement of the welding ribbon connection blocks 40 in the middle A area can be 3 rows, 10 rows or 20 rows, which is not specifically limited here.

[0048] Since the carriers need to be collected on the soldering ribbon 200, the spacing between the soldering ribbon connecting blocks 40 needs to be close to the maximum length of the carrier transmission, and the longer the transmission length is, the higher the conductivity requirement for the fine grid metal electrode is. If the transmission length is too short, the number of soldering ribbons 200, the difficulty of subsequent packaging and the cost of the soldering ribbon 200 will increase. Therefore, in this embodiment, the soldering ribbon 200 is preferably 1 / 40mm thick. Figure 1 To illustrate the relative positions in the figure, the spacing W3 between the center line of the welding ribbon connection block 40 located at the end of the battery cell 10 and the edge of the battery cell 10 is in the range of 0.6mm-3mm, the spacing W4 between the welding ribbon connection block 40 located at the end of the battery cell 10 and the adjacent welding ribbon connection block 40 is in the range of 6mm-16mm, the spacing W5 between two adjacent welding ribbon connection blocks 40 located in the middle of the battery cell 10 is in the range of 6mm-16mm, and the deviation between W5 and W4 is less than 3mm.

[0049] Specifically, the soldering strip connection block 40 is formed by printing, inkjet printing of conductive silver paste, conductive silver glue or solder paste.

[0050] In this embodiment, the length of the soldering ribbon connection block 40 ranges from 100 um to 4 mm, the width of the soldering ribbon connection block 40 ranges from 50 um to 500 um, and the thickness of the soldering ribbon connection block 40 ranges from 10 um to 50 um.

[0051] In the width direction of the battery cell 10, an insulating block 50 is provided between two adjacent welding strip connection blocks 40 to Figure 2 For explanation of the relative position, an insulating block 50 is provided between the soldering strip connecting blocks 40 on two adjacent first fine grid lines 20 and second fine grid lines 30. The insulating block 50 is installed in the first disconnection area 101 and the second disconnection area 102, and the insulating block 50 is connected to the soldering strip 200.

[0052] Since the welding strip 200 is connected to the insulating block 50, in order to prevent the welding strip 200 from contacting the first fine grid line 20 and the second fine grid line 30 and causing a short circuit, the length of the insulating block 50 should be greater than the width of the welding strip 200, and the width of the insulating block 50 at least covers the insulating block 50 connecting line and the area with the opposite polarity to the welding strip connecting block 40. Therefore, in this embodiment, the length W6 of the insulating block 50 ranges from 2mm to 5mm, the length of the insulating block 50 is 2.5 times to 10 times the width of the welding strip 200, and the thickness of the insulating block 50 is 2um to 40um.

[0053] by Figure 3 The relative positions in the figure are explained. In the case of overlapping multiple battery cells 10, the welding strip 200 includes a first welding strip 210 and a second welding strip 220. The first welding strip 210 is overlapped at the middle of the battery cell 10, and the second welding strip 220 is overlapped at both ends of the battery cell 10. The cross-sectional area of ​​the first welding strip 210 is 2 times to 6 times the cross-sectional area of ​​the second welding strip 220. The spacing between the second welding strip 220 and the edge of the battery cell 10 ranges from 0.3 mm to 1 mm. Since the current collected by the second welding strip 220 is half of the current collected by the first welding strip 210, the cross-sectional area of ​​the second welding strip 220 can be 0.25 times to 0.5 times the cross-sectional area of ​​the first welding strip 210, thereby reducing the stress of the second welding strip 220 located at the end of the battery cell 10 during welding.

[0054] Furthermore, the battery module 1000 also includes a film layer 300, a back film 400, a back plate 500, a front film 600 and a front plate 700. The film layer 300 is arranged at the bottom of the battery cell 10 and the surface of the welding strip 200. The front film 600 is stacked on the upper surface of the film layer 300 above the welding strip 200. The front plate 700 is stacked on the upper surface of the front film 600. The back film 400 is stacked on the lower surface of the film layer 300 below the battery cell 10. The back plate 500 is stacked on the lower surface of the back film 400, thereby forming the battery module 1000.

[0055] In this embodiment, the adhesive film is any one of EVA adhesive film, POE adhesive film, TPU adhesive film or PI adhesive film. The back plate 500 and the front plate 700 can be any one of glass, polyvinyl fluoride composite film, PET, TPE, polyamide, aluminum-plastic plate, and the front adhesive film 600 and the back adhesive film 400 can be any one of EVA adhesive film, POE adhesive film, TPU adhesive film, which are not specifically limited here.

[0056] The embodiment of the present invention further provides a method for manufacturing a battery module 1000. The battery module 1000 is manufactured. The method for manufacturing the battery module 1000 includes:

[0057] S1: Laying the welding ribbon 200 on two adjacent battery strings so that the welding ribbon 200 covers the welding ribbon connecting block 40 and the insulating block 50;

[0058] S2: attaching the adhesive film layer 300 to the surface of the battery cell 10 on which the welding ribbon 200 is overlapped, and heating the adhesive film layer 300 to connect the welding ribbon 200 and the battery cell 10, wherein the heating temperature ranges from 50°C to 100°C;

[0059] S3: sequentially stacking a front adhesive film 600 and a front plate 700 on the adhesive film layer 300;

[0060] S4: attaching the adhesive film layer 300 to the bottom surface of the battery cell 10 and heating the adhesive film layer 300 at a heating temperature ranging from 50° C. to 100° C.;

[0061] S5: The backside adhesive film 400 and the back plate 500 are sequentially stacked on the lower surface of the adhesive film layer 300, and then laminated at a temperature of 130°C-200°C to form a module.

[0062] The beneficial effects of the busbar-free back contact battery 100, battery module 1000 and preparation method of the embodiments of the present invention include, for example:

[0063] The main grid-free back contact battery 100 includes a battery cell 10, a plurality of first fine grid lines 20 for collecting a first polarity, and a plurality of second fine grid lines 30 for collecting a second polarity, wherein the plurality of first fine grid lines 20 and the plurality of second fine grid lines 30 are alternately arranged in sequence along the width direction of the battery cell 10, and the first fine grid lines 20 and the second fine grid lines 30 both have a disconnection area, and the disconnection area is used to cooperate with the welding strip 200, wherein the width range of the disconnection area is 1mm-5mm; the first fine grid lines 20 and the second fine grid lines 30 are both provided with a plurality of welding strip connecting blocks 40, and the plurality of welding strip connecting blocks 40 are provided on the first fine grid lines 20 and the second fine grid lines 30. The individual soldering ribbon connection blocks 40 are respectively arranged at both ends and the middle of the battery cell 10, wherein the spacing between the soldering ribbon connection blocks 40 located at both ends of the battery cell 10 ranges from 6mm to 16mm, and the spacing between two adjacent soldering ribbon connection blocks 40 located in the middle of the battery cell 10 ranges from 6mm to 16mm; in the width direction of the battery cell 10, an insulating block 50 is arranged between two adjacent soldering ribbon connection blocks 40, and the length of the insulating block 50 ranges from 2mm to 5mm, and the length of the insulating block 50 is 2.5 times to 10 times the difference in the width of the soldering ribbon 200.

[0064] The battery module 1000 includes a battery string, which includes a welding strip 200 and a plurality of main grid-free back contact batteries 100. The polarities of two adjacent battery cells 10 are opposite. The welding strip 200 is overlapped on the welding strip connecting block 40 and the insulating block 50 of two adjacent battery cells 10. The width of the welding strip 200 ranges from 0.3 mm to 2 mm. The welding strip 200 includes a first welding strip 210 and a second welding strip 220. The first welding strip 210 is overlapped on the middle of the battery cell 10, and the second welding strip 220 is overlapped on both ends of the battery cell 10. The cross-sectional area of ​​the first welding strip 210 is 2 to 6 times the cross-sectional area of ​​the second welding strip 220.

[0065] The manufacturing method of the battery module 1000 manufactures the battery module 1000, and the manufacturing method of the battery module 1000 includes: laying the welding ribbon 200 on two adjacent battery strings, so that the welding ribbon 200 covers the welding ribbon connecting block 40 and the insulating block 50; attaching the adhesive film layer 300 to the side surface of the battery cell 10 overlapped with the welding ribbon 200, heating the adhesive film layer 300 to connect the welding ribbon 200 and the battery cell 10, and the heating temperature ranges from 50°C to 100°C.

[0066] In summary, the embodiments of the present invention provide a busbar-free back-contact battery 100, a battery module 1000 and a preparation method, wherein the busbar-free back-contact battery 100 comprises a battery cell 10, a plurality of first fine grid lines 20 for collecting a first polarity and a plurality of second fine grid lines 30 for collecting a second polarity, wherein the plurality of first fine grid lines 20 and the plurality of second fine grid lines 30 are alternately arranged in sequence along the width direction of the battery cell 10, the lengths of the first fine grid lines 20 and the second fine grid lines 30 are substantially the same, and no fold line or busbar is required, the first fine grid lines 20 and the second fine grid lines 30 both have a disconnection area, the disconnection area is used to cooperate with the welding strip 200, and the width range of the disconnection area is 1mm-5mm, thereby reserving sufficient tolerance for the installation of the welding strip 200 to avoid the welding strip 200 from contacting the first fine grid line 20 or the second fine grid line 30 and thus causing a short circuit; the first fine grid lines 20 and the second fine grid lines 30 are both provided with a plurality of welding strip connection blocks 40, and the plurality of welding strip connection blocks 40 are respectively arranged on the battery cell 10 At both ends and the middle, the spacing between the soldering strip connection block 40 located at the end of the battery cell 10 and the adjacent soldering strip connection block 40 is in the range of 6mm-16mm, and the spacing between two adjacent soldering strip connection blocks 40 located in the middle of the battery cell 10 is in the range of 6mm-16mm, and the difference between the spacing between two adjacent soldering strip connection blocks 40 located in the middle of the battery cell 10 and the spacing between the soldering strip connection block 40 located at the end of the battery cell 10 and the adjacent soldering strip connection block 40 is less than 3mm, so that the spacing between two adjacent soldering strip connection blocks 40 can be closer to the maximum length of carrier transmission, so that as many carriers as possible can flow back to the soldering strip 200; in the width direction of the battery cell 10, an insulating block 50 is provided between two adjacent soldering strip connection blocks 40, and the length of the insulating block 50 is in the range of 2mm-5mm, and the length of the insulating block 50 is 2.5 times to 10 times the difference in the width of the soldering strip 200, thereby reducing the stress of the soldering strips 200 on both sides of the battery. The overall process is simple, ensuring the consistency of the length of the fine grid and improving the battery deformation problem.

[0067] The battery module 1000 includes a battery string, the battery string includes a welding strip 200 and a plurality of main grid-free back contact batteries 100, the polarities of two adjacent battery cells 10 are opposite, the welding strip 200 is overlapped on the welding strip connection block 40 and the insulating block 50 of the two adjacent battery cells 10, and the width of the welding strip 200 ranges from 0.3 mm to 2 mm; the welding strip 200 includes a first welding strip 210 and a second welding strip 220, the first welding strip 210 is overlapped on the middle of the battery cell 10, the second welding strip 220 is overlapped on both ends of the battery cell 10, and the cross-sectional area of ​​the first welding strip 210 is 2 to 6 times the cross-sectional area of ​​the second welding strip 220. When in use, the battery module 1000 can ensure that the length of the fine grid is consistent, and improve the problem of battery deformation.

[0068] The manufacturing method of the battery module 1000 manufactures the battery module 1000, and the manufacturing method of the battery module 1000 includes: laying the welding strip 200 on two adjacent battery strings, so that the welding strip 200 covers the welding strip connecting block 40 and the insulating block 50; attaching the adhesive film layer 300 to the surface of the battery cell 10 on which the welding strip 200 overlaps, heating the adhesive film layer 300 to connect the welding strip 200 and the battery cell 10, and the heating temperature ranges from 50° C. to 100° C. The manufacturing method of the battery module 1000 is simple and convenient to use.

[0069] The embodiments of the present invention are described in detail below, which are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0070] Example 1

[0071] A busbar-free back contact battery 100 comprises a battery cell 10, a plurality of first fine grid lines 20 for collecting a first polarity, and a plurality of second fine grid lines 30 for collecting a second polarity, wherein the plurality of first fine grid lines 20 and the plurality of second fine grid lines 30 are alternately arranged in sequence along the width direction of the battery cell 10. Figure 1 The relative positions in FIG. 1 are described as follows. The first thin gate lines 20 and the second thin gate lines 30 are alternately arranged in sequence along the vertical direction.

[0072] The first fine grid line 20 and the second fine grid line 30 both have a disconnection area, and the disconnection area is used to cooperate with the welding strip 200. Specifically, the disconnection area includes a first disconnection area 101 and a second disconnection area 102. The first disconnection area 101 is located on the first fine grid line 20, and all the first disconnection areas 101 are located on the same straight line. The second disconnection area 102 is located on the second fine grid line 30, and all the second disconnection areas 102 are located on the same straight line. The first disconnection area 101 and the second disconnection area 102 are staggered. Among them, the first disconnection area 101 and the second disconnection area 102 are both located in the middle of the battery cell 10, and all the first disconnection areas 101 are arranged in a row, and all the second disconnection areas 102 are arranged in a row, so that Figure 1 To illustrate the relative positions in the figure, the spacing between the first fine grid line 20 and / or the second fine grid line 30 and the edge of the battery cell 10 is W1, and the spacing W1 between the end of the first fine grid line 20 and / or the second fine grid line 30 and the edge of the battery cell 10 is 1.5 mm; the width of the disconnected area of ​​the first fine grid line 20 and / or the second fine grid line 30 in the middle of the battery cell 10 is W2, and W2 is 2 mm.

[0073] In this embodiment, the width of the first fine gate line 20 and the second fine gate line 30 is 25 um, and the thickness of the first fine gate line 20 and the second fine gate line 30 is 10 um.

[0074] The width of the soldering strip 200 is 1 mm, wherein the width of the second soldering strip 220 is 0.5 mm. There is a tolerance between the width of the soldering strip 200 and W1 and W2, so that the first disconnection area 101 and the second disconnection area 102 can completely accommodate the soldering strip 200, thereby preventing the soldering strip 200 from contacting the first fine grid line 20 or the second fine grid line 30 after being installed in the first disconnection area 101 and the second disconnection area 102, thereby causing a short circuit; at the same time, the values ​​of W1 and W2 should be as small as possible while ensuring that sufficient tolerance is reserved for the soldering strip 200, thereby reducing the transmission of carriers in the area without fine grids, thereby reducing power loss.

[0075] In this embodiment, a plurality of welding ribbon connection blocks 40 are provided on the first fine grid lines 20 and the second fine grid lines 30, and the plurality of welding ribbon connection blocks 40 are respectively arranged at both ends and the middle of the battery cell 10, and the welding ribbon connection blocks 40 on the adjacently arranged first fine grid lines 20 and the second fine grid lines 30 are staggered.

[0076] Since the carriers need to be collected on the soldering ribbon 200, the spacing between the soldering ribbon connecting blocks 40 needs to be close to the maximum length of the carrier transmission, and the longer the transmission length is, the higher the conductivity requirement for the fine grid metal electrode is. If the transmission length is too short, the number of soldering ribbons 200, the difficulty of subsequent packaging and the cost of the soldering ribbon 200 will increase. Therefore, in this embodiment, the soldering ribbon 200 is preferably 1 / 40mm thick. Figure 1 To illustrate the relative positions in the figure, the spacing W3 between the center line of the welding ribbon connection block 40 located at the end of the battery cell 10 and the edge of the battery cell 10 is 1 mm; the spacing W4 between the welding ribbon connection block 40 located at the end of the battery cell 10 and the adjacent welding ribbon connection block 40 is 10 mm; the spacing W5 between two adjacent welding ribbon connection blocks 40 located in the middle of the battery cell 10 is 10 mm; and the deviation between W5 and W4 is less than 2 mm.

[0077] Specifically, the length of the soldering ribbon connection block 40 is 2 um, the width of the soldering ribbon connection block 40 is 300 um, and the thickness of the soldering ribbon connection block 40 is 15 um.

[0078] In the width direction of the battery cell 10, an insulating block 50 is provided between two adjacent welding strip connection blocks 40 to Figure 2 For explanation of the relative position, an insulating block 50 is provided between the soldering strip connecting blocks 40 on two adjacent first fine grid lines 20 and second fine grid lines 30. The insulating block 50 is installed in the first disconnection area 101 and the second disconnection area 102, and the insulating block 50 is connected to the soldering strip 200.

[0079] Since the welding strip 200 is connected to the insulating block 50, in order to prevent the welding strip 200 from contacting the first fine grid line 20 and the second fine grid line 30 and causing a short circuit, the length of the insulating block 50 should be greater than the width of the welding strip 200, and the width of the insulating block 50 should at least cover the insulating block 50 connecting line and the area with the opposite polarity to the welding strip connecting block 40. Therefore, in this embodiment, the length W6 of the insulating block 50 is 4mm; the length of the insulating block 50 is 4-10 times the width of the welding strip 200, and the thickness of the insulating block 50 is 10um.

[0080] by Figure 3 , in the case of overlapping multiple battery cells 10, the welding strip 200 includes a first welding strip 210 and a second welding strip 220, the first welding strip 210 is overlapped at the middle of the battery cell 10, and the second welding strip 220 is overlapped at both ends of the battery cell 10, the cross-sectional area of ​​the first welding strip 210 is 2 times to 6 times the cross-sectional area of ​​the second welding strip 220, and the spacing between the second welding strip 220 and the edge of the battery cell 10 ranges from 0.5 mm to 1.5 mm. Since the current collected by the second welding strip 220 is half of the current collected by the first welding strip 210, the cross-sectional area of ​​the second welding strip 220 is 0.25 times the cross-sectional area of ​​the first welding strip 210, thereby reducing the stress of the second welding strip 220 located at the end of the battery cell 10 during welding.

[0081] Example 2

[0082] Refer to Example 1, which is different from Example 1 in that the spacing W1 between the ends of the first fine grid line 20 and the second fine grid line 30 and the edge of the battery cell 10 is 1 mm, and the width W2 of the disconnected area of ​​the first fine grid line 20 and the second fine grid line 30 in the middle of the battery cell 10 is 1 mm.

[0083] Example 3

[0084] The process is carried out with reference to Example 1. The difference from Example 1 is that the width of the first thin gate line 20 and the second thin gate line 30 is 45 um.

[0085] Example 4

[0086] The process is carried out with reference to Example 1. The difference from Example 1 is that the width of the soldering strip 200 is 0.3 mm, and the width of the second soldering strip 220 is 0.5 mm.

[0087] Example 5

[0088] The process is carried out with reference to Example 1, except that the spacing W3 between the center line of the soldering ribbon connection block 40 at the end of the battery cell 10 and the edge of the battery cell 10 is 2 mm; the spacing W4 between the soldering ribbon connection block 40 at the end of the battery cell 10 and the adjacent soldering ribbon connection block 40 is 15 mm; and the spacing W5 between two adjacent soldering ribbon connection blocks 40 at the middle of the battery cell 10 is 15 mm.

[0089] Example 6

[0090] The process is carried out with reference to Example 1. The difference from Example 1 is that the length of the soldering ribbon connection block 40 is 1 mm, the width of the soldering ribbon connection block 40 is 100 um, and the thickness of the soldering ribbon connection block 40 is 15 um.

[0091] Example 7

[0092] The method is carried out with reference to Example 1. The difference from Example 1 is that the length W6 of the insulating block 50 is 3 mm; the length of the insulating block 50 is 3-8 times the width of the welding strip 200, and the thickness of the insulating block 50 is 20 um.

[0093] Example 8

[0094] The method is carried out with reference to Example 1. The difference from Example 1 is that the spacing between the second welding ribbon 220 and the edge of the battery cell 10 is in the range of 0.2 mm-0.6 mm, and the cross-sectional area of ​​the second welding ribbon 220 is 0.5 times the cross-sectional area of ​​the first welding ribbon 210 .

[0095] Comparative Example 1

[0096] The process is carried out with reference to Example 1. The difference from Example 1 is that a printed silver paste main grid is used to replace the soldering strip connection block 40, and the silver paste main grid connects the fine grids of the same polarity together.

[0097] Comparative Example 2

[0098] Refer to Example 1. Unlike Example 1, the spacing W1 between the ends of the first fine grid line 20 and the second fine grid line 30 and the edge of the battery cell 10 in Example 1 is 4.5 mm, and the width W2 of the disconnected area of ​​the first fine grid line 20 and the second fine grid line 30 in the middle of the battery cell 10 is 6 mm.

[0099] Comparative Example 3

[0100] The process is carried out with reference to Example 1. The difference from Example 1 is that the width of the first thin gate line 20 and the second thin gate line 30 is 120 um.

[0101] Comparative Example 4

[0102] The process is performed with reference to Example 1, except that the width of the first welding strip 210 is 2 mm, and the width of the second welding strip 220 is 1 mm.

[0103] Comparative Example 5

[0104] Refer to Example 1, which is different from Example 1 in that the spacing W3 between the center line of the welding ribbon connection block 40 located at the end of the battery cell 10 and the edge of the battery cell 10 is 3.5 mm; the spacing W4 between the welding ribbon connection block 40 located at the end of the battery cell 10 and the adjacent welding ribbon connection block 40 is 18 mm; the spacing W5 between two adjacent welding ribbon connection blocks 40 located in the middle of the battery cell 10 is 18 mm.

[0105] Comparative Example 6

[0106] The method is carried out with reference to Example 1. The difference from Example 1 is that the length of the soldering ribbon connection block 40 is 50 um, the width of the soldering ribbon connection block 40 is 50 um, and the thickness of the soldering ribbon connection block 40 is 10 um.

[0107] Comparative Example 7

[0108] The process is performed with reference to Example 1, except that the length W6 of the insulating block 50 is 1.8 mm; the length of the insulating block 50 is 1-2 times the width of the welding strip 200, and the thickness of the insulating block 50 is 20 um.

[0109] Comparative Example 8

[0110] Refer to Example 1, except that the spacing between the second welding strip 220 and the edge of the battery cell 10 is in the range of 0.1 mm to 0.5 mm, and the cross-sectional area of ​​the second welding strip 220 is 1 times the cross-sectional area of ​​the first welding strip 210.

[0111] Test Case

[0112] The relevant data of the battery silver paste consumption, the yield rate and the power of the battery module 1000 obtained in the above-mentioned embodiments and comparative examples were collected respectively, and the results are shown in Table 1.

[0113] Table 1

[0114]

[0115] It can be seen from the above results that, compared with the comparative example, the embodiment scheme of the present invention adopts a busbar-free design, which can significantly reduce the amount of silver paste used, thereby reducing the production cost of the battery. Further, according to Example 1 and Examples 2-8, it can be seen that the preferred busbar-free metal electrode scheme of the present invention can take into account the silver paste consumption, module power and yield of the battery, which is conducive to large-scale production.

[0116] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A busbar-free back contact battery, It is characterized in that The invention comprises a battery cell (10), a plurality of first fine grid lines (20) for collecting first polarity, and a plurality of second fine grid lines (30) for collecting second polarity, wherein the plurality of first fine grid lines (20) and the plurality of second fine grid lines (30) are arranged alternately in sequence along the width direction of the battery cell (10), and the first fine grid lines (20) and the second fine grid lines (30) both have a disconnection area, and the disconnection area is used to cooperate with a welding strip (200), wherein the width of the disconnection area ranges from 1 mm to 5 mm; A plurality of soldering strip connection blocks (40) are provided on each of the first fine grid line (20) and the second fine grid line (30), and the plurality of soldering strip connection blocks (40) are respectively arranged at both ends and the middle of the battery cell (10), wherein the spacing between the soldering strip connection block (40) located at the end of the battery cell (10) and the adjacent soldering strip connection block (40) ranges from 6 mm to 16 mm, and the spacing between two adjacent soldering strip connection blocks (40) located in the middle of the battery cell (10) ranges from 6 mm to 16 mm, and the difference between the spacing between two adjacent soldering strip connection blocks (40) located in the middle of the battery cell (10) and the spacing between the soldering strip connection block (40) located at the end of the battery cell (10) and the adjacent soldering strip connection block (40) is less than 3 mm; In the width direction of the battery cell (10), an insulating block (50) is provided between two adjacent welding strip connection blocks (40), the length of the insulating block (50) ranges from 2 mm to 5 mm, and the length of the insulating block (50) is 2.5 times to 10 times the width of the welding strip (200); The disconnection area comprises a first disconnection area (101) and a second disconnection area (102); the first disconnection area (101) is located on the first fine grid line (20), and all the first disconnection areas (101) are located on the same straight line; the second disconnection area (102) is located on the second fine grid line (30), and all the second disconnection areas (102) are located on the same straight line; the first disconnection area (101) and the second disconnection area (102) are staggered.

2. The busbar-free back contact cell according to claim 1, It is characterized in that The width of the first fine gate line (20) and / or the second fine gate line (30) is in the range of 10 um to 100 um.

3. The busbar-free back contact cell according to claim 1, It is characterized in that The thickness of the first fine grid line (20) and / or the second fine grid line (30) is in the range of 5 um to 20 um.

4. The busbar-free back contact cell according to claim 1, It is characterized in that The spacing between the end of the first fine grid line (20) and / or the end of the second fine grid line (30) and the edge of the battery cell (10) is in the range of 1 mm to 4 mm.

5. The busbar-free back contact cell according to claim 1, It is characterized in that The length of the soldering ribbon connection block (40) ranges from 100 um to 500 um, and the width of the soldering ribbon connection block (40) ranges from 50 um to 4 mm.

6. The busbar-free back contact cell according to claim 1, It is characterized in that The spacing between the center line of the welding ribbon connection block (40) located at the end of the battery cell (10) and the edge of the battery cell (10) is in the range of 0.6 mm to 3 mm.

7. A battery module, comprising a battery string, It is characterized in that The battery string comprises a welding strip (200) and a plurality of busbar-free back-contact batteries (100) according to any one of claims 1 to 6, the polarities of two adjacent battery cells (10) are opposite, the welding strip (200) is overlapped on the welding strip connection block (40) and the insulating block (50) of the two adjacent battery cells (10), and the width of the welding strip (200) ranges from 0.3 mm to 2 mm; The welding strip (200) comprises a first welding strip (210) and a second welding strip (220), the first welding strip (210) being overlapped at the middle of the battery cell (10), the second welding strip (220) being overlapped at both ends of the battery cell (10), and the cross-sectional area of ​​the first welding strip (210) being 2 to 6 times the cross-sectional area of ​​the second welding strip (220).

8. The battery module according to claim 7, It is characterized in that The battery module (1000) further comprises an adhesive film layer (300), wherein the adhesive film layer (300) is arranged on the bottom of the battery cell (10) and on the surface of the welding strip (200).

9. A method for manufacturing a battery module, It is characterized in that The battery module according to claim 7 is manufactured, and the manufacturing method of the battery module comprises: Laying the welding ribbon (200) on two adjacent battery strings, so that the welding ribbon (200) covers the welding ribbon connection block (40) and the insulating block (50); The adhesive film layer (300) is attached to a surface of the battery cell (10) on one side of which the welding strip (200) is overlapped, and the adhesive film layer (300) is heated to connect the welding strip (200) and the battery cell (10), wherein the heating temperature ranges from 50°C to 100°C.

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