Tab welding structure and battery

Abstract

The utility model provides a tab welding structure and a battery, and the tab welding structure comprises a plurality of tab groups, each tab group is provided with a plurality of laminated composite tabs, and each composite tab is provided with a substrate layer and conductive layers located at the two sides of the substrate layer along the thickness direction; the composite tabs are arranged in a staggered manner and / or gradually changed in size, so that a step structure is formed on at least one side of the tab group; the plurality of tab groups are stacked, so that a plurality of welding grooves distributed along the stacking direction are formed among the plurality of tab groups, and at least one inner side wall of each welding groove is of a step structure; the adapter is provided with a convergence part which is electrically connected with the pole and a plurality of welding parts which are connected with the convergence part; at least part of the welding part is located in the welding groove and welded to the stepped structure. Therefore, the resistance value of the tabs during welding can be reduced, the overcurrent capacity of the battery is improved, the welding strength can be improved, and the method can be suitable for the condition that the number of layers of composite tabs is large.

Description

Technical Field

[0001] The present application relates to the field of battery processing technology, and in particular to a tab welding structure and a battery. Background Art

[0002] In order to improve the safety performance of the battery, the composite current collector uses polymer materials such as PET (polyethylene terephthalate) and PP (polypropylene) as the matrix, and a layer of aluminum foil is plated on the surface of both sides of the matrix by thermal evaporation, or a layer of copper / aluminum foil is plated on the surface of both sides of the matrix by magnetron sputtering + thermal evaporation, so as to obtain a composite material with light weight and good tensile strength.

[0003] During the battery processing, multiple tabs are formed on the composite current collector. In the traditional method, multiple tabs are stacked together and welded to achieve conduction of multiple tabs. However, since the middle layer of the composite current collector is a polymer insulating layer, the resistance of the electrode formed by multiple tabs will increase, and the bonding force between the composite current collector layers will be poor, resulting in an increased probability of cold welding. Utility Model Content

[0004] In view of this, the present application provides a tab welding structure with good welding strength and good current carrying capacity.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A tab welding structure, comprising:

[0007] A plurality of tab groups, each tab group having a plurality of composite tabs arranged in a stacked manner, each of the composite tabs having a base layer and a conductive layer located on both sides of the base layer in a thickness direction; the plurality of composite tabs are staggered and / or gradually sized to form a step structure on at least one side of the tab group; the plurality of tab groups are stacked to form a plurality of welding grooves arranged in a stacking direction between the plurality of tab groups, and at least one inner side wall of each welding groove is the step structure;

[0008] The adapter comprises a collector for electrically connecting to the pole and a plurality of welding parts connected to the collector; at least part of the welding parts is located in the welding groove and welded to the step structure.

[0009] Optionally, the thickness of the welding portion gradually decreases along a direction approaching a bottom of the welding groove.

[0010] Optionally, the adapter includes a plurality of adapter plates, and the plurality of adapter plates are sequentially spaced apart along the thickness direction to form the plurality of welding portions.

[0011] Optionally, the adapter further includes a connecting portion, and the plurality of welding portions and the bus bar are respectively connected to two sides of the connecting portion in the thickness direction.

[0012] Optionally, both inner side walls of the welding groove are the stepped structures and are welded to the welding portions simultaneously.

[0013] And / or, stepped structures are formed on both side surfaces of at least part of the tab groups, and the two stepped structures on the same tab group are respectively welded to two adjacent welding portions.

[0014] Optionally,

[0015] The plurality of tab groups have 10 - 30 of the composite tabs, and the dimension of the step of the stepped structure in the step direction is 1 - 1.5 millimeters.

[0016] Or, the plurality of tab groups have 30 - 50 of the composite tabs, and the dimension of the step of the stepped structure in the step direction is 0.5 - 1 millimeter.

[0017] Optionally, the thickness of the composite tab is 4 - 8 micrometers, and the stepped structure has 3 - 12 layers.

[0018] Optionally, the plurality of composite tabs are offset in the width direction to form the stepped structure.

[0019] Optionally,

[0020] The dimensions of the plurality of composite tabs in the length direction increase or decrease in sequence to form the stepped structure.

[0021] And / or, the dimensions of the plurality of composite tabs in the width direction increase or decrease in sequence to form the stepped structure.

[0022] A battery includes a tab welding structure, and the tab welding structure is the tab welding structure described in any one of the above.

[0023] For the tab welding structure and the battery provided by this application, the welding portion of the adapter extends into the welding groove between the plurality of tab groups and is welded to the stepped structure. The method of offset welding can effectively reduce the area occupied by the base layer during welding, thereby effectively reducing the tab resistance during welding, increasing the overcurrent capacity of the battery, and reducing the risk of false soldering during the welding process. Moreover, multiple welding grooves are formed between the plurality of tab groups and respectively carry and weld the plurality of welding portions, which can make there be multiple layers of intersections between the adapter and the plurality of tab groups, which can not only improve the welding strength but also be applicable to the case of a large number of layers of composite tabs. Description of the Drawings

[0024] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0025] Figure 1 It is a top view of the tab welding structure shown in the first embodiment;

[0026] Figure 2 It is a front view of the tab welding structure shown in the first embodiment;

[0027] Figure 3 It is a welding schematic of the tab welding structure shown in the first embodiment Figure 1 ;

[0028] Figure 4 It is a welding schematic of the tab welding structure shown in the second embodiment Figure 2 ;

[0029] Figure 5 It is a cross-sectional view of the composite tab shown in some embodiments.

[0030] In the figure: 1. Tab group; 11. Step structure; 12. Welding groove; 2. Adapter; 21. Welding part; 22. Current collecting part; 23. Connecting part; 101. Substrate layer; 102. Conductive layer. Detailed implementation manners

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0032] As Figures 1 - 5 shown, the embodiments of the present application provide a tab welding structure, including a plurality of tab groups 1 and an adapter 2.

[0033] Each tab group 1 includes a plurality of composite tabs arranged in a stacked manner. The plurality of composite tabs are arranged in a staggered manner, and / or the sizes of the plurality of composite tabs are gradually changed, so that a stepped structure 11 is formed on at least one side of the tab group 1. For example, a stepped structure 11 is formed only on one side of a single tab group 1, or stepped structures 11 are formed on both sides of a single tab group 1. Here, the stepped structure 11 on the tab group 1 is located at a position close to the edge on the side of the tab group 1. Specifically, the sizes of the plurality of composite tabs can be the same, and the stepped structure 11 is formed by arranging them in a staggered manner during stacking; or the sizes of the plurality of composite tabs can be different, and they are not arranged in a staggered manner during stacking, and the stepped structure 11 is formed by gradual change in size; or the sizes of the plurality of composite tabs can be different, and the stepped structure 11 is formed by arranging them in a staggered manner and gradual change in size during stacking.

[0034] Among them, as Figure 5 shown, the composite tab includes a substrate layer 101 and two conductive layers 102. The two conductive layers 102 are respectively arranged on both sides in the thickness direction (i.e., the Z direction in Figure 5 ) of the substrate layer 101. For example, the substrate layer 101 is made of one or more of PET, PP, and PI, and the conductive layer 102 is made of an aluminum layer or a copper layer. The thickness of the composite tab is generally set to 5-8 microns.

[0035] A plurality of tab groups 1 are arranged in a stacked manner and form an integral structure (i.e., the tab part of the battery cell). Since there is a stepped structure 11 on at least one side of the tab group 1, a plurality of welding grooves 12 arranged in the stacking direction (i.e., the Z direction in Figure 2 ) are formed between the plurality of tab groups 1. For example, a welding groove 12 is formed between any two adjacent tab groups 1, and the plurality of welding grooves 12 are all arranged on the same side of the tab part of the battery cell to facilitate connection by a connecting piece. Moreover, at least one inner sidewall in each welding groove 12 is the above-mentioned stepped structure 11. For example, stepped structures 11 are formed on two opposite side surfaces of two adjacent tab groups 1, and both inner sidewalls of the welding groove 12 formed between the two tab groups 1 are stepped structures 11; or stepped structures 11 are formed on two side surfaces with the same orientation of two adjacent tab groups 1, and one inner sidewall of the welding groove 12 formed between the two tab groups 1 is a stepped structure 11.

[0036] The adapter 2 includes a busbar portion 22 and a plurality of welding portions 21. A busbar portion 22 is electrically connected to the plurality of welding portions 21. One of the busbar portions 22 is used for electrically connecting to the pole post of the battery cell, and the plurality of welding portions 21 are used for electrically connecting to the plurality of tab groups 1. Among them, a part or all of the welding portions 21 are respectively located in the plurality of welding grooves 12, that is, there is one welding portion 21 in each welding groove 12, and the number of welding portions 21 is greater than or equal to the number of welding grooves 12. At the same time, the welding portion 21 located in the welding groove 12 is welded to the stepped structure 11 in the welding groove 12, so that the adapter 2 is electrically connected to the plurality of tab groups 1, which is beneficial to realizing the electrical connection between the plurality of tab groups 1 (that is, the tab part of the battery cell) and the pole post of the battery cell.

[0037] With such a setting, the welding portion 21 of the adapter extends into the welding groove 12 between the plurality of tab groups 1 and is welded to the stepped structure 11. The method of offset welding can effectively reduce the area occupied by the base layer during welding, thereby effectively reducing the tab resistance during welding, increasing the over-current capacity of the battery, and reducing the risk of false soldering during the welding process. Moreover, a plurality of welding grooves 12 are formed between the plurality of tab groups 1 and respectively carry and weld the plurality of welding portions 21, which can make there be multiple layers of intersections between the adapter 2 and the plurality of tab groups 1, which can not only improve the welding strength but also be applicable to the case of a large number of composite tab layers.

[0038] In some embodiments, the thickness of the welding portion 21 gradually decreases along the direction close to the bottom of the welding groove 12. Due to the setting of the stepped structure 11, the width of the welding groove 12 gradually decreases in the direction from the groove opening to the groove bottom. By matching the shape of the welding portion 21 with the shape of the welding groove 12, the welding portion 21 can be embedded in the welding groove 12, so that the welding portion 21 abuts against the stepped structure 11, improving the welding stability between the welding portion 21 and the stepped structure 11.

[0039] Of course, in other solutions, the welding portion 21 can also be set as a plate with a uniform thickness, and the welding portion 21 can be brought into contact with the stepped structure 11 by extruding the plurality of tab groups 1 in the thickness direction.

[0040] In some other solutions, the adapter 2 includes a plurality of adapter plates, and the plurality of adapter plates are sequentially spaced apart in the thickness direction to form a plurality of welding portions 21. After the plurality of adapter plates extend into the welding groove 12 and are welded to the stepped structure 11, one ends of the plurality of adapter plates away from the welding groove 12 are connected together to form a busbar portion 22 and are simultaneously electrically connected to the pole post of the battery cell. In this way, in the form of a plurality of adapter plates, it is convenient for connection and processing.

[0041] Such as Figure 3 、 4As shown, the adapter 2 has a welding portion 21, a busbar portion 22, and a connecting portion 23. A plurality of welding portions 21 and busbar portions 22 are respectively connected to both sides of the connecting portion 23 in the thickness direction. The electrical connection between one busbar portion 22 and a plurality of welding portions 21 is achieved through the connecting portion 23, and the structure is stable and reliable.

[0042] In some embodiments, both inner sidewalls of the welding groove 12 are provided with a stepped structure 11. The two stepped structures 11 are simultaneously welded to the same welding portion 21, so that both sides of one welding portion 21 are welded within the welding groove 12, further enhancing the welding strength and current-carrying capacity of the adapter 2.

[0043] In some other solutions, based on or not based on the above solution, stepped structures 11 are formed on both side surfaces of part or all of the tab groups 1. The two stepped structures 11 on the same tab group 1 are respectively welded to two adjacent welding portions 21, further enhancing the welding strength and current-carrying capacity of the tab group 1. Specifically, as Figure 4 shown, when the tab group 1 with stepped structures 11 formed on both side surfaces is located in the outermost layer of a plurality of tab groups 1, one of the two stepped structures 11 is located within the welding groove 12, and the other is located on the outer side surface of the tab group 1. Correspondingly, for the two welding portions 21 electrically connected to the tab group 1, one is located within the welding groove 12, and the other is located on the outer sidewall of the welding groove 12 (i.e., the outer side surface of the tab group 1). That is to say, part of the welding portions 21 are located within the welding groove 12, and the other part of the welding portions 21 are located on the outer side surfaces of a plurality of tab groups 1 (the tab portions of the battery cell). In this way, the welding strength and current-carrying capacity are further enhanced by the form of clamping the tab group 1 through the welding portions 21.

[0044] In some preferred solutions, a plurality of tab groups 1 have 10 - 30 composite tabs, and the dimension of the step of the stepped structure 11 in the stepped direction (i.e., the misalignment length) is 1 - 1.5 millimeters; or, a plurality of tab groups 1 have 30 - 50 composite tabs, and the dimension of the step of the stepped structure 11 in the stepped direction (i.e., the misalignment length) is 0.5 - 1 millimeter. Among them, the stepped direction is the Figure 1 Y direction in. In this preferred solution, the number of composite tabs is set to 10 - 50. When the number of composite tabs is small, the misalignment length of the stepped structure 11 is large, and when the number of composite tabs is large, the misalignment length of the stepped structure 11 is small, so that the total length of the stepped structure 11 is relatively balanced and consistent, which is beneficial to adapting to the adapter 2 and enhancing the welding strength of the adapter 2.

[0045] In addition, the thickness of the composite tab is 4 - 8 microns, the stepped structure 11 has 3 - 12 layers. For example, the number of composite tabs is 10 - 50, the length of the longest composite tab is 16 - 56 millimeters, the thickness of the composite tab is 4 - 8 microns, the stacked thickness of all the composite tabs (i.e., all the tab groups 1) is 40 - 400 microns, and the distance between two peaks (the peak is the position between two adjacent welding grooves 12) is 24 - 192 microns.

[0046] In some embodiments, multiple composite tabs in the same tab group 1 are offset in the width direction (i.e., the Y direction in Figure 1 ) to form the stepped structure 11. During processing, the lengths of the individual composite tabs can be kept consistent, and the width of the strip during winding can be kept consistent, which is beneficial to saving the material cost of the battery cell during winding. Among them, the sizes of the multiple composite tabs can be the same or different. Here, the width direction is perpendicular to the length direction, and the length direction is the direction in which the tab is away from the battery cell body.

[0047] In other solutions, the sizes of multiple composite tabs in the same tab group 1 increase or decrease in the length direction (i.e., the X direction in Figure 1 ) to form the stepped structure 11. Among them, the sizes of the multiple composite tabs in the width direction can be kept the same. When connecting the adapter 2, the adapter 2 is located on the side of the tab away from the battery cell body, which can avoid interference between the adapter 2 and other structures.

[0048] In addition to this, the sizes of multiple composite tabs can also increase or decrease in sequence in the width direction (i.e., the Y direction in Figure 1 ) to form the stepped structure 11. Among them, the sizes of the multiple composite tabs in the length direction can be kept the same. During processing, the lengths of the individual composite tabs can be kept consistent, and the width of the strip during winding can be kept consistent, which is beneficial to saving the material cost of the battery cell during winding.

[0049] The embodiment of the present application provides a battery including the tab welding structure in the above - mentioned embodiment. With such a setting, the welding part 21 of the adapter extends into the welding groove 12 between multiple tab groups 1 and is welded to the stepped structure 11. The offset welding method can effectively reduce the area occupied by the base layer during welding, thereby effectively reducing the tab resistance during welding, increasing the over - current capacity of the battery, and reducing the risk of false soldering during the welding process. Moreover, multiple welding grooves 12 are formed between multiple tab groups 1 and respectively carry and weld multiple welding parts 21, which can make there be multiple layers of interleaving between the adapter 2 and multiple tab groups 1, which can not only improve the welding strength but also be applicable to the case of a large number of composite tab layers.

[0050] The basic principles of the present application have been described in conjunction with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are only examples and not limitations. It cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present application. Additionally, the specific details disclosed above are only for the purposes of illustration and facilitating understanding, and are not limitations. The above details do not limit the present application to necessarily implementing with the above specific details.

[0051] The block diagrams of the devices, apparatuses, equipment, and systems involved in the present application are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open-ended terms, meaning "including but not limited to", and can be used interchangeably with each other. The word "or" and "and" used herein refer to the word "and / or", and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to", and can be used interchangeably with each other.

[0052] It should also be noted that in the devices, equipment, and methods of the present application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present application.

[0053] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be very apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0054] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth", and "sixth" used in the description of the embodiments of the present application are only for more clearly elaborating the technical solutions and cannot be used to limit the protection scope of the present application.

[0055] The above description has been given for purposes of illustration and description. In addition, this description does not intend to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

Claims

1. An electrode tab welding structure, characterized in that, Comprising: A plurality of tab groups (1), each tab group (1) having a plurality of composite tabs arranged in a stacked manner, each of the composite tabs having a base layer (101) and conductive layers (102) located on both sides of the base layer in the thickness direction; the plurality of composite tabs are arranged in a staggered manner and / or have a gradually changing size, so as to form a stepped structure (11) on at least one side of the tab group (1); the plurality of tab groups (1) are arranged in a stacked manner, so as to form a plurality of welding grooves (12) arranged in the stacking direction between the plurality of tab groups (1), and at least one inner sidewall of each welding groove (12) is the stepped structure (11); A transfer member having a current collecting portion (22) for electrically connecting to a pole post and a plurality of welding portions (21) connected to the current collecting portion; at least part of the welding portions (21) are located in the welding grooves (12) and are welded to the stepped structure (11).

2. The tab welding structure according to claim 1, wherein The thickness of the welding portion (21) gradually decreases in the direction close to the bottom of the welding groove (12).

3. The tab welding structure according to claim 1, wherein, The transfer member includes a plurality of transfer sheets, and the plurality of transfer sheets are sequentially spaced apart in the thickness direction to form the plurality of welding portions (21).

4. The tab welding structure according to claim 1, characterized in that The transfer member further includes a connecting portion (23), and the plurality of welding portions (21) and the current collecting portion (22) are respectively connected to both sides of the connecting portion (23) in the thickness direction.

5. The tab welding structure according to claim 1, wherein Both inner sidewalls of the welding groove (12) are the stepped structure (11) and are simultaneously welded to the welding portion (21); And / or, both side surfaces of at least part of the tab groups (1) form the stepped structure (11), and the two stepped structures (11) on the same tab group (1) are respectively welded to two adjacent welding portions (21).

6. The tab welding structure according to claim 1, wherein The plurality of tab groups (1) have 10 - 30 of the composite tabs, and the size of the step of the stepped structure (11) in the step direction is 1 - 1.5 mm; Or, the plurality of tab groups (1) have 30 - 50 of the composite tabs, and the size of the step of the stepped structure (11) in the step direction is 0.5 - 1 mm.

7. The tab welding structure according to claim 1, wherein, The thickness of the composite tab is 4 - 8 μm, and the stepped structure (11) has 3 - 12 layers.

8. The tab welding structure according to claim 1, wherein, The plurality of composite tabs are offset in the width direction to form the stepped structure (11).

9. The tab welding structure according to claim 1, wherein The sizes of the plurality of composite tabs in the length direction increase or decrease in sequence to form the stepped structure (11); And / or, the sizes of the plurality of composite tabs in the width direction increase or decrease in sequence to form the stepped structure (11).

10. A battery, including an electrode tab welding structure, is characterized in that, The tab welding structure is the tab welding structure according to any one of claims 1 - 9.

Images