Method for manufacturing a tab, tab, and battery pack

Abstract

The embodiment of the application discloses a connecting piece manufacturing method, a connecting piece and a battery pack. The connecting piece manufacturing method comprises the following steps: providing a material belt, the material belt is provided with at least one product area, each product area comprises a welding area; roughening the surface of the welding area to form a plurality of first grooves and a plurality of second grooves on one side surface of the welding area, the first grooves and the second grooves are not overlapped, and the depths of the first grooves and the second grooves are different; and cutting the material belt to obtain the connecting piece corresponding to the product area. The surface roughness of the welding area of the connecting piece is increased, so that the reflectivity of laser is reduced, and the risk of false welding or poor welding is avoided.

Description

Technical Field

[0001] This application relates to the field of battery accessory technology, and in particular to a method for manufacturing a connecting piece, the connecting piece, and a battery pack. Background Technology

[0002] Currently, with the increasing awareness of environmental protection, more and more people are paying attention to environmental issues, especially the abnormal changes in global climate, which have received high attention and have become a social problem that human society needs to solve. To alleviate environmental problems, relevant technical personnel have proposed a solution of replacing gasoline-powered vehicles with new energy vehicles, achieving the effects of energy diversification, pollution reduction, and improved energy efficiency.

[0003] Battery packs are the primary power source for new energy vehicles and have become one of the core components of electric vehicles. A battery pack consists of multiple individual cells, which are typically connected to terminals and tabs via connecting tabs. The connection between the connecting tabs and terminals is achieved using laser welding. During research and practice with existing technologies, the inventors of this application discovered that, during laser welding, the side of the connecting tab opposite the laser welding head is a smooth surface. During welding, reflection reduces the absorption rate of the laser light by the connecting tab, posing a risk of incomplete or poor welds. Summary of the Invention

[0004] This application provides a method for manufacturing a connector, the connector, and a battery pack, which can improve the technical problem that the high reflectivity of the side of the connector used for laser welding can easily lead to incomplete welding or poor welding.

[0005] This application provides a method for manufacturing a connecting piece, comprising:

[0006] Step B1: Provide a strip of material, the strip of material having at least one product area, each product area including a welding area;

[0007] Step B2: Roughen the surface of the welding area to form a plurality of first grooves and a plurality of second grooves on one side surface of the welding area. The first grooves and the second grooves do not overlap and have different depths.

[0008] Step B3: Cut the strip to obtain the connecting piece corresponding to the product area.

[0009] Optionally, in some embodiments of this application, in step B1, the welding area includes a plurality of first areas and second areas, wherein the second areas enclose and form a plurality of first areas;

[0010] Step B2 includes:

[0011] Step B21: Perform a first roughening treatment on the surface of the first region to form the first groove on the surface of the first region;

[0012] Step B22: Perform a second roughening treatment on the surface of the second region to form a plurality of the second grooves on the surface of the second region;

[0013] In step B2, steps B21 and B22 are executed alternately, and the order of steps B21 and B22 can be changed, with steps B21 and B22 being executed at least once.

[0014] Optionally, in some embodiments of this application, in step B21, a first punch is used to press the surface of the first region, thereby performing a first roughening treatment on the surface of the first region.

[0015] In step B22, a second punch is used to press the surface of the second region, thereby performing a second roughening treatment on the surface of the second region.

[0016] Optionally, in some embodiments of this application, the depth of the first groove is greater than the depth of the second groove.

[0017] Optionally, in some embodiments of this application, the depth of the first groove is 0.03 mm to 0.1 mm.

[0018] Optionally, in some embodiments of this application, the depth of the second groove is 0.01 mm to 0.05 mm.

[0019] This application embodiment also provides a connecting piece with a welding area. One side surface of the welding area is provided with a plurality of first grooves and a plurality of second grooves. The first grooves and the second grooves do not overlap, and the depths of the first grooves and the second grooves are different.

[0020] Optionally, in some embodiments of this application, the depth of the first groove is greater than the depth of the second groove.

[0021] Optionally, in some embodiments of this application, the depth of the first groove is 0.03 mm to 0.1 mm, and the depth of the second groove is 0.01 mm to 0.05 mm.

[0022] This application also provides a battery pack including a plurality of electrically connected battery cells, wherein a positive electrode connecting piece is welded to the positive electrode of the battery cell, and a negative electrode connecting piece is welded to the negative electrode of the battery cell, wherein the positive electrode connecting piece and / or the negative electrode connecting piece adopts the connecting piece as described above.

[0023] This application embodiment employs a method for manufacturing a connecting piece, the connecting piece, and a battery pack. By roughening the surface of the welding area of ​​the connecting piece, multiple first grooves and multiple second grooves are formed on one side of the welding area. The first grooves and second grooves do not overlap, and the depths of the first grooves and second grooves are different. This increases the surface roughness of the welding area of ​​the connecting piece, thereby reducing the reflectivity of the laser and avoiding the risk of incomplete welding or poor welding. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic flowchart illustrating the method for manufacturing the connecting piece provided in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the material strip structure provided in an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of step B21 provided in an embodiment of this application;

[0028] Figure 4 A bottom view of the first punch provided in an embodiment of this application;

[0029] Figure 5 This is a schematic diagram of the main structure of the first punch provided in an embodiment of this application;

[0030] Figure 6 This is a schematic diagram of step B22 provided in an embodiment of this application;

[0031] Figure 7 A bottom view of the second punch provided in an embodiment of this application;

[0032] Figure 8 This is a schematic diagram of the main structure of the second punch provided in an embodiment of this application;

[0033] Figure 9 A schematic diagram of step B31 provided in an embodiment of this application;

[0034] Figure 10 A schematic diagram of step B33 provided in an embodiment of this application;

[0035] Figure 11 A schematic diagram of step B34 provided in an embodiment of this application;

[0036] Figure 12 This is a schematic diagram of the structure of the connecting piece provided in an embodiment of this application.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1-Material strip, 10-Product area, 100-Connecting piece, 110-Welding area, 111-First area, 112-Second area, 1121-First sub-area, 1122-Second sub-area, 113-First groove, 114-Second groove, 200-First punch, 210-Protrusion, 300-Second punch, 310-Stamping pattern, 400-Third punch, 500-Fourth punch, X-First direction, Y-Second direction. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this application. It is understood that the accompanying drawings are provided for reference and illustration only, and are not intended to limit this application. The connection relationships shown in the accompanying drawings are only for clear description and do not limit the connection method.

[0040] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component, or there may be an intervening component. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be noted that, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; or as a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application.

[0041] It should also be noted that in the description of this application, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] Please see Figure 1 This application provides a method for manufacturing a connecting piece, including:

[0043] Step B1, as follows Figure 2 As shown, a strip 1 is provided, which has at least one product area 10, and each product area 10 includes a welding area 110;

[0044] Step B2, as follows Figure 3 and Figure 6 As shown, the surface of the welding area 110 is roughened to form a plurality of first grooves 113 and a plurality of second grooves 114 on one side surface of the welding area 110. The first grooves 113 and the second grooves 114 do not overlap, and the depths of the first grooves 113 and the second grooves 114 are different.

[0045] Step B3, as follows Figures 9 to 12 As shown, the strip 1 is cut to obtain the connecting piece 100 corresponding to the product area 10.

[0046] In the manufacturing method of the connecting piece in this application embodiment, the surface of the welding area 110 of the connecting piece 100 is roughened to form a plurality of first grooves 113 and a plurality of second grooves 114 on one side surface of the welding area 110. The first grooves 113 and the second grooves 114 do not overlap and the depths of the first grooves 113 and the second grooves 114 are different, which can increase the surface roughness of the welding area 110 of the connecting piece 100, so as to reduce the reflectivity of the laser and thus avoid the risk of false soldering or poor soldering.

[0047] Specifically, in step B1, such as Figure 2 As shown, the welding area 110 includes multiple first areas 111 and second areas.

[0048] 112, the second region 112 encloses and forms multiple first regions 111.

[0049] like Figure 2As shown, the second region 112 includes multiple first sub-regions 1121 and multiple second sub-regions 1122. The first sub-regions 1121 extend along a first direction X, and the multiple first sub-regions 1121 are spaced apart along a second direction Y. The second sub-regions 1122 extend along the second direction Y, and the multiple second sub-regions 1122 are spaced apart along the first direction X. The multiple first sub-regions 1121 and multiple second sub-regions 1122 intersect and enclose to form multiple first regions 111. In this embodiment, the first direction X and the second direction Y are perpendicular, and the multiple first regions 111 are arranged in an array. Of course, depending on the actual situation and specific requirements, the first direction X and the second direction Y can be set at other angles, as long as the first direction X and the second direction Y intersect; no particular limitation is made here.

[0050] Specifically, step B2 includes:

[0051] Step B21, as follows Figure 3 As shown, the surface of the first region 111 is subjected to a first roughening treatment to form a first groove 113 on the surface of the first region 111;

[0052] Step B22, as follows Figure 6 As shown, a second roughening treatment is applied to the surface of the second region 112 to form a plurality of second grooves 114 on the surface of the second region 112;

[0053] In step B2, steps B21 and B22 are executed alternately, and the order of steps B21 and B22 can be interchanged, but steps B21 and B22 are executed at least once. Under this setup, step B21 forms the first groove 113, and step B22 forms the second groove 114; that is, the two grooves of different depths are formed separately through corresponding processes. In this embodiment, the density of the first groove 113 is less than the density of the second groove 114.

[0054] It should be noted that, in order to distinguish the roughening processes of steps B21 and B22, the roughening process of step B21 is named the first roughening process, and the roughening process of step B22 is named the second roughening process. That is, the first roughening process is not necessarily the roughening process performed first in step B2, and the second roughening process is not necessarily performed after the first roughening process. The above naming is only to limit the first roughening process to the process corresponding to the formation of the first groove 113, and the second roughening process to the process corresponding to the formation of the second groove 114.

[0055] In one embodiment of this application, step B2 may include: first, performing a first roughening treatment on the surface of the first region 111 to form a first groove 113 on the surface of the first region 111; then, performing a second roughening treatment on the surface of the second region 112 to form a plurality of second grooves 114 on the surface of the second region 112, thereby forming grooves of different depths, which can increase the surface roughness of the welding area 110 of the connecting piece 100, so as to reduce the reflectivity of the laser and thus avoid the risk of incomplete welding or poor welding.

[0056] In another embodiment of this application, step B2 may include: first, performing a second roughening treatment on the surface of the second region 112 to form a plurality of second grooves 114 on the surface of the second region 112; then, performing a first roughening treatment on the surface of the first region 111 to form a first groove 113 on the surface of the first region 111, thereby forming grooves of different depths, which can increase the surface roughness of the welding area 110 of the connecting piece 100 in order to reduce the reflectivity of the laser and thus avoid the risk of incomplete welding or poor welding.

[0057] In another embodiment of this application, step B2 may include: first, performing a second roughening treatment on the surface of the second region 112 to form a plurality of second grooves 114 on the surface of the second region 112; then, performing a first roughening treatment on the surface of the first region 111 to form a first groove 113 on the surface of the first region 111; subsequently, performing a second roughening treatment on the surface of the second region 112 again to form a plurality of second grooves 114 on the surface of the second region 112. By forming grooves of different depths through the above process, the surface roughness of the welding area 110 of the connecting piece 100 can be increased, so as to reduce the reflectivity of the laser and thus avoid the risk of incomplete welding or poor welding. In this embodiment, the second groove 114 formed when the surface of the second region 112 is subjected to the second roughening treatment for the first time is different in shape (texture) from the second groove 114 formed when the surface of the second region 112 is subjected to the second roughening treatment for the second time. The second groove 114 formed when the surface of the second region 112 is subjected to the second roughening treatment for the first time is at least partially intersecting and connected with the second groove 114 formed when the surface of the second region 112 is subjected to the second roughening treatment for the second time, which can increase the frosted effect of the second region 112 and help reduce reflection.

[0058] It is understandable that the order and number of steps B21 and B22 in step B2 can be adjusted appropriately according to the actual situation and specific needs, and no special restrictions are imposed here.

[0059] Specifically, such as Figures 3 to 5As shown, in step B21, a first punch 200 is used to punch the surface of the first region 111, thereby performing a first roughening treatment on the surface of the first region 111. In this embodiment, the working end face of the first punch 200 is provided with a plurality of protrusions 210. When the first punch 200 punches the surface of the first region 111, a first groove 113 can be punched into the surface of the first region 111, with each protrusion 210 corresponding to one first groove 113. In this embodiment, the plurality of protrusions 210 are arranged in an array, and correspondingly, the plurality of first grooves 113 formed are also arranged in an array.

[0060] Specifically, the cross-sectional shape of the protrusion 210 can be rectangular, triangular, circular, elliptical, pentagonal, or other shapes. The cross-sectional shape of the first groove 113 is adapted to the cross-sectional shape of the protrusion 210, that is, the cross-sectional shape of the first groove 113 can be rectangular, triangular, circular, elliptical, pentagonal, or other shapes. Of course, the cross-sectional shape of the first groove 113 can be appropriately modified according to the actual situation and specific requirements, and is not particularly limited here.

[0061] Specifically, such as Figures 6 to 8 As shown, in step B22, the second punch 300 is used to punch the surface of the second region 112, thereby performing a second roughening treatment on the surface of the second region 112. In this embodiment, the working end face of the second punch 300 is provided with a punching pattern 310. The punching pattern 310 is formed by roughening the working end face of the second punch 300 through EDM. Therefore, the punching pattern 310 has an irregular texture structure. When the second punch 300 punches the surface of the second region 112, multiple second grooves 114 can be punched on the surface of the second region 112, and the second grooves 114 have an irregular texture structure.

[0062] Specifically, the depth of the first groove 113 and the second groove 114 is less than the thickness of the strip 1, that is, the depth of the first groove 113 and the second groove 114 is less than the thickness of the connecting piece 100, so as to form a rough surface on one side of the welding area 110 of the connecting piece 100, while the other side of the welding area 110 of the connecting piece 100 remains a flat surface.

[0063] If the depths of the first groove 113 and the second groove 114 are too large, the strength of the welding area 110 may be affected; if the depths of the first groove 113 and the second groove 114 are too small, the surface roughness of the welding area 110 cannot be guaranteed. To balance these issues, the depths of the first groove 113 and the second groove 114 should be set to 0.5% to 20% of the thickness of the strip 1 (connecting piece 100). For example, the depth of the first groove 113 can be 0.5%, 1%, 2.5%, 5%, 10%, 15%, or 20% of the thickness of the strip 1 (connecting piece 100), and the depth of the second groove 114 can be 0.5%, 1%, 2.5%, 5%, 10%, 15%, or 20% of the thickness of the strip 1 (connecting piece 100).

[0064] Specifically, the thickness of strip 1 (connecting piece 100) is 0.5 mm to 2 mm. For example, the thickness of connecting piece 100 can be 0.8 mm, 1 mm, 1.5 mm, or 2 mm. Of course, the thickness of strip 1 (connecting piece 100) can be adjusted appropriately according to the actual situation and specific requirements, and is not particularly limited here.

[0065] Specifically, the depth of the first groove 113 is greater than the depth of the second groove 114, which increases the surface roughness of the welding area 110 of the connecting piece 100, thereby reducing the reflectivity of the laser and avoiding the risk of incomplete welding or poor welding. In this embodiment, by forming a deeper first groove 113 in the first region 111, an embossed effect can be formed on the welding area 110; by forming a shallower second groove 114 in the second region 112, a matte effect can be formed on the welding area 110.

[0066] It should be noted that the stamping pattern 310 on the working end face of the second punch 300 is a full-surface pattern. Since the depth of the second groove 114 is less than the depth of the first groove 113, the stamping pattern 310 of the second punch 300 will not affect the depth of the first groove 113 when step B22 is executed after step B21. Similarly, when step B21 is executed after step B22, since the protrusion 210 of the first punch 200 is set corresponding to the first area 111, the protrusion 210 of the first punch 200 will not affect the depth of the second groove 114.

[0067] Specifically, the depth of the first groove 113 is 0.03 mm to 0.1 mm. For example, the depth of the first groove 113 can be 0.03 mm, 0.05 mm, 0.07 mm or 0.1 mm, as long as the depth of the first groove 113 is greater than the depth of the second groove 114, and no special limitation is made here.

[0068] Specifically, the depth of the second groove 114 is 0.01 mm to 0.05 mm. For example, the depth of the second groove 114 can be 0.01 mm, 0.03 mm or 0.05 mm, as long as the depth of the second groove 114 is less than the depth of the first groove 113, and no special limitation is made here.

[0069] Specifically, such as Figure 2 and Figure 12 As shown, the center-to-center distance D1 between two adjacent first grooves 113 (first regions 111) is 0.5 mm to 2 mm, and similarly, the distance D2 between two adjacent first grooves 113 (first regions 111) is 0.5 mm to 2 mm. For example, the center-to-center distance D1 between two adjacent first grooves 113 can be 0.5 mm, 1 mm, or 2 mm, and the distance D2 between two adjacent first grooves 113 (first regions 111) can be 0.5 mm, 1 mm, or 2 mm. This arrangement ensures sufficient space between two adjacent first grooves 113 for the second groove 114, thus guaranteeing the surface roughness of the welding area 110. Of course, the distance D2 and center-to-center distance D1 between two adjacent first grooves 113 can be adjusted appropriately according to the actual situation and specific requirements, and are not specifically limited here.

[0070] Specifically, step B3 includes:

[0071] Step B31, as follows Figure 9 As shown, the third punch 400 is used to punch the product area 10 of the strip 1 on both sides along the width direction, so that the part of the strip 1 corresponding to the product area 10 is separated from the strip 1 on both sides along the width direction.

[0072] Step B32: Deburr the product area 10 of the material strip 1;

[0073] Step B33, as follows Figure 10 As shown, the fourth punch 500 is used to punch one side of the product area 10 of the strip 1 along the length direction, so that the part of the strip 1 corresponding to the product area 10 is separated from the strip 1 on one side of the length direction.

[0074] Step B34, as follows Figure 11As shown, a fourth punch 500 is used to punch the product area 10 of the strip 1 along the other side of its length, causing the portion of the strip 1 corresponding to the product area 10 to separate from the strip 1 on the other side of its length. Through this arrangement, the portion of the strip 1 corresponding to the product area 10 is separated from the strip 1, thereby obtaining the connecting piece 100 corresponding to the product area 10. In this embodiment, the shapes of the opposite sides of the fourth punch 500 are adapted to the shapes of the opposite sides of the product area 10 of the strip 1 along its length. Therefore, one fourth punch 500 can be used to punch the opposite sides of the product area 10 of the strip 1, saving one punch and reducing mold costs.

[0075] In this embodiment, steps B2 and B3 can be implemented using a progressive die. The progressive die includes a moving die and a fixed die arranged opposite to each other. The moving die is equipped with a first punch 200, a second punch 300, a third punch 400, and a fourth punch 500. The fixed die has multiple stations, with the first punch 200, second punch 300, third punch 400, and fourth punch 500 corresponding to different station settings. By placing the product area 10 of the strip 1 at the corresponding station, the product area 10 of the strip 1 can be processed by the corresponding punch.

[0076] Please see Figure 12 At the same time, combined Figures 2-11 This application embodiment also provides a connecting piece 100, which has a welding area 110. One side surface of the welding area 110 has a plurality of first grooves 113 and a plurality of second grooves 114. The first grooves 113 and the second grooves 114 do not overlap, and the depths of the first grooves 113 and the second grooves 114 are different. In this embodiment, the density of the first grooves 113 is less than the density of the second grooves 114.

[0077] Specifically, the welding area 110 includes multiple first areas 111 and second areas 112, with the second areas 112 enclosing and forming multiple first areas 111. A first groove 113 is provided in the first area 111, and a second groove 114 is provided in the second area 112.

[0078] Specifically, the second region 112 includes multiple first sub-regions 1121 and multiple second sub-regions 1122. The first sub-regions 1121 extend along a first direction X, and the multiple first sub-regions 1121 are spaced apart along a second direction Y. The second sub-regions 1122 extend along the second direction Y, and the multiple second sub-regions 1122 are spaced apart along the first direction X. The multiple first sub-regions 1121 and multiple second sub-regions 1122 intersect and enclose to form multiple first regions 111. In this embodiment, the first direction X and the second direction Y are perpendicular, and the multiple first regions 111 are arranged in an array. Of course, depending on the actual situation and specific requirements, the first direction X and the second direction Y can be set at other angles, as long as the first direction X and the second direction Y intersect; no special limitation is made here.

[0079] Specifically, the cross-sectional shape of the first groove 113 can be rectangular, triangular, circular, elliptical, pentagonal, or other shapes. Of course, the cross-sectional shape of the first groove 113 can be modified appropriately according to the actual situation and specific requirements, and is not particularly limited here. In this embodiment, the second groove 114 has an irregular textured structure.

[0080] Specifically, the depth of the first groove 113 and the second groove 114 is less than the thickness of the connecting piece 100, that is, a rough surface is formed on one side of the welding area 110 of the connecting piece 100. This rough surface is used to fix the connecting piece 100 to the positive or negative electrode of the battery cell by laser welding. The other side of the welding area 110 of the connecting piece 100 is still a relatively flat surface.

[0081] Specifically, the depths of the first groove 113 and the second groove 114 are set to 0.5% to 20% of the thickness of the connecting piece 100. For example, the depth of the first groove 113 can be 0.5%, 1%, 2.5%, 5%, 10%, 15%, or 20% of the thickness of the strip 1 (connecting piece 100), and the depth of the second groove 114 can be 0.5%, 1%, 2.5%, 5%, 10%, 15%, or 20% of the thickness of the strip 1 (connecting piece 100).

[0082] Specifically, the thickness of the connecting piece 100 is 0.5 mm to 2 mm. For example, the thickness of the connecting piece 100 can be 0.8 mm, 1 mm, 1.5 mm, or 2 mm. Of course, the thickness of the connecting piece 100 can be adjusted appropriately according to the actual situation and specific requirements, and is not specifically limited here.

[0083] Specifically, the depth of the first groove 113 is greater than the depth of the second groove 114, which can increase the surface roughness of the welding area 110 of the connecting piece 100, so as to reduce the reflectivity of the laser and thus avoid the risk of incomplete welding or poor welding.

[0084] Specifically, the depth of the first groove 113 is 0.03 mm to 0.1 mm. For example, the depth of the first groove 113 can be 0.03 mm, 0.05 mm, 0.07 mm or 0.1 mm, as long as the depth of the first groove 113 is greater than the depth of the second groove 114, and no special limitation is made here.

[0085] Specifically, the depth of the second groove 114 is 0.01 mm to 0.05 mm. For example, the depth of the second groove 114 can be 0.01 mm, 0.03 mm or 0.05 mm, as long as the depth of the second groove 114 is less than the depth of the first groove 113, and no special limitation is made here.

[0086] Specifically, the center-to-center distance D1 between two adjacent first grooves 113 (first regions 111) is 0.5 mm to 2 mm, and similarly, the distance D2 between two adjacent first grooves 113 (first regions 111) is 0.5 mm to 2 mm. For example, the center-to-center distance D1 between two adjacent first grooves 113 can be 0.5 mm, 1 mm, or 2 mm, and the distance D2 between two adjacent first grooves 113 (first regions 111) can be 0.5 mm, 1 mm, or 2 mm. This arrangement ensures sufficient space between two adjacent first grooves 113 for the second groove 114, thus guaranteeing the surface roughness of the welding area 110. Of course, the distance D2 and center-to-center distance D1 between two adjacent first grooves 113 can be adjusted appropriately according to the actual situation and specific requirements, and are not specifically limited here.

[0087] This application embodiment also provides a battery pack, including a plurality of electrically connected battery cells, wherein a positive electrode connecting piece is welded to the positive electrode of the battery cell, and a negative electrode connecting piece is welded to the negative electrode of the battery cell, and the positive electrode connecting piece and / or the negative electrode connecting piece adopts the connecting piece 100 as described above.

[0088] In the specification and claims of this application, the terms "comprising / including" and "having / including" and variations thereof are used to specify the presence of the stated features, values, steps or components, but do not exclude the presence or addition of one or more other features, values, steps, components or combinations thereof.

[0089] Some features of this application are described in different embodiments for clarity; however, these features may also be described in combination in a single embodiment. Conversely, some features of this application are described only in a single embodiment for brevity; however, these features may also be described individually or in any suitable combination in different embodiments.

[0090] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for manufacturing a connecting piece, characterized in that, include: Step B1: Provide a strip of material, the strip of material having at least one product area, each product area including a welding area; Step B2: Roughen the surface of the welding area to form a plurality of first grooves and a plurality of second grooves on one side surface of the welding area. The first grooves and the second grooves do not overlap and have different depths. The depth of the first groove is greater than the depth of the second groove; Step B2 includes: first, performing a second roughening treatment on the surface of the second region to form a plurality of second grooves on the surface of the second region; then, performing a first roughening treatment on the surface of the first region to form a first groove on the surface of the first region; subsequently, performing a second roughening treatment on the surface of the second region again to form a plurality of second grooves on the surface of the second region. The second groove formed when the second roughening treatment is applied to the surface of the second region for the first time is different in shape from the second groove formed when the second roughening treatment is applied to the surface of the second region for the second time. The second groove formed when the second roughening treatment is applied to the surface of the second region for the first time intersects and connects with the second groove formed when the second roughening treatment is applied to the surface of the second region for the second time. The second groove has an irregular texture structure. Step B3: Cut the strip to obtain the connecting piece corresponding to the product area.

2. The method for manufacturing the connecting piece according to claim 1, characterized in that, In step B2, a first punch is used to press the surface of the first region, thereby performing a first roughening treatment on the surface of the first region. The surface of the second region is punched using a second punch, thereby performing a second roughening treatment on the surface of the second region.

3. The method for manufacturing the connecting piece according to claim 1, characterized in that, The depth of the first groove is 0.03 mm to 0.1 mm.

4. The method for manufacturing the connecting piece according to claim 1, characterized in that, The depth of the second groove is 0.01 mm to 0.05 mm.

5. A connecting piece, characterized in that, The connecting piece is manufactured by the method of any one of claims 1-4. The connecting piece has a welding area, and one side surface of the welding area has a plurality of first grooves and a plurality of second grooves. The first grooves and the second grooves do not overlap, and the depths of the first grooves and the second grooves are different.

6. The connecting piece according to claim 5, characterized in that, The depth of the first groove is greater than the depth of the second groove.

7. The connecting piece according to claim 6, characterized in that, The depth of the first groove is 0.03 mm to 0.1 mm, and the depth of the second groove is 0.01 mm to 0.05 mm.

8. A battery pack, characterized in that, The battery includes multiple electrically connected battery cells, wherein a positive electrode connecting piece is welded to the positive electrode of the battery cell, and a negative electrode connecting piece is welded to the negative electrode of the battery cell, wherein the positive electrode connecting piece and / or the negative electrode connecting piece are connecting pieces as described in any one of claims 5-7.

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