Tab welding structure and battery

Abstract

The utility model provides a tab welding structure and a battery, and the tab welding structure comprises a tab group which is provided with a plurality of laminated composite tabs, and each composite tab is provided with a substrate layer, and a first conductive layer and a second conductive layer which are respectively located at the two sides of the substrate layer along the thickness direction; the conducting strips are overlapped and electrically connected with the first conducting layer of the composite tab; wherein the plurality of composite tabs are laminated along the thickness direction, and are laminated at the position of the lowest layer of composite tab, so that the plurality of conducting strips are staggered along with the plurality of composite tabs, and a step structure is formed on one side of the plurality of conducting strips. Therefore, the conductive sheet is connected to the single side of the composite tab, so that the conductivity of the composite tab to external electric connection is enhanced, the internal resistance of the battery is reduced, the heating temperature rise at the tab is reduced, the processing technology is simple, the quality risk caused by poor welding is reduced, and the reliability of a product is improved.

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] The composite current collector uses polymer materials such as PET (PP) 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 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. However, since the matrix material is an insulator, the metal coatings on both sides need to be conducted through current, which requires additional processing.

[0003] In the prior art, copper / aluminum foils are generally ultrasonically welded on the two coating surfaces of the composite current collector, and the active materials on both sides of the composite current collector are electrically connected to the outside through the composite welded copper / aluminum foils. However, this method directly welds on both sides of the composite current collector, resulting in a large continuous welding area, poor welding stability and consistency, large internal resistance, high heat generation, and poor electrical performance of the battery product. Utility Model Content

[0004] In view of this, the present application provides a tab welding structure and a battery, which have good electrical conductivity and small internal resistance.

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

[0006] A tab welding structure, comprising:

[0007] A tab group, comprising a plurality of composite tabs stacked in layers, each of the composite tabs comprising a base layer and a first conductive layer and a second conductive layer respectively located on both sides of the base layer in a thickness direction;

[0008] A plurality of conductive sheets, the conductive sheets overlap with and are electrically connected to the first conductive layer of the composite tab;

[0009] The multiple composite tabs are pressed together along the thickness direction and pressed together at the position of the bottom composite tab, so that the multiple conductive sheets are displaced along with the multiple composite tabs and a stepped structure is formed on one side of the multiple conductive sheets.

[0010] Optionally, in the length direction of the composite electrode tab, the size of the conductive sheet is larger than the size of the adjacent composite electrode tab.

[0011] Optionally, two adjacent conductive sheets are respectively arranged on two side surfaces of the same composite electrode tab along the thickness direction.

[0012] Optionally, the conductive sheet is partially bonded to a side surface of the composite electrode tab.

[0013] Optionally, the bonding area between the conductive sheet and the composite electrode tab accounts for 6%-60% of the overlapping area between the conductive sheet and the composite electrode tab.

[0014] Optionally include:

[0015] The connecting piece is electrically connected to at least one of the conductive layers of each of the composite tabs.

[0016] Optionally, in the length direction of the composite pole ear, the size of the overlapping area between each composite pole ear and the connecting sheet is greater than or equal to 1 mm; in the width direction of the composite pole ear, the connecting sheet occupies at least 10% of the size of the composite pole ear; and the thickness of the conductive sheet is set to 0.05-0.3 mm.

[0017] Optionally,

[0018] The multiple composite tabs have consistent sizes in the length direction;

[0019] And / or, in the length direction of the plurality of composite tabs, the sizes of the plurality of conductive sheets are consistent.

[0020] A battery comprises a tab welding structure, wherein the tab welding structure is the tab welding structure as described in any one of the above items.

[0021] Optionally, a pole piece is included, the pole piece has a coating area and a pole lug area, the conductive sheet is arranged in the pole lug area, and the interval between the conductive sheet and the coating area is greater than or equal to 0.5 mm.

[0022] The tab welding structure and battery provided in the present application connect a conductive sheet on one side of the composite tab to enhance the conductivity of the external electrical connection of the composite tab, reduce the internal resistance of the battery, and reduce the heat rise at the tab. In addition, the processing technology is simple, which is conducive to reducing the quality risks caused by poor welding and improving the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 A cross-sectional view of a welding structure of a pole ear (after kneading) shown in some embodiments;

[0025] Figure 2 A top view of a pole ear welding structure (after kneading) shown in some embodiments;

[0026] Figure 3 A cross-sectional view of a welding structure of a pole ear (before kneading) shown in some embodiments;

[0027] Figure 4 A cross-sectional view of a composite tab according to some embodiments;

[0028] Figure 5 A cross-sectional view of a tab welding structure (with a connecting sheet and without hiding the conductive sheet) shown in some embodiments;

[0029] Figure 6 The figure is a top view of a tab welding structure (with a connecting piece and a hidden conductive piece) according to some embodiments.

[0030] In the figure: 1. composite electrode ear; 2. conductive sheet; 3. stepped structure; 4. coating area; 5. connecting sheet; 11. base layer; 12. first conductive layer; 13. second conductive layer. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] like Figure 1-Figure 6 As shown, an embodiment of the present application provides a tab welding structure, including a tab group and a plurality of conductive sheets 2.

[0033] The tab group has a plurality of composite tabs 1. For example, the number of composite tabs 1 is set to five, six or more. Figure 1 The composite tab 1 includes a base layer 11, a first conductive layer 12 and a second conductive layer 13, and the first conductive layer 12 and the second conductive layer 13 are respectively arranged in the thickness direction (i.e., Figure 1 The Z direction and Figure 4 On both sides of the upper and lower directions), for example, the base layer 11 is set to one or more of PET, PP and PI, the first conductive layer 12 and the second conductive layer 13 are set to aluminum layers or copper layers, and the thickness of the composite electrode ear 1 is generally set to 5-8 microns.

[0034] The conductive sheet 2 is attached to the side of the composite tab 1 having the first conductive layer 12, that is, the conductive sheet 2 is attached to the side of the first conductive layer 12 away from the second conductive layer 13, and the conductive sheet 2 overlaps and is electrically connected to the first conductive layer 12. Here, the conductive sheet 2 can be set as a metal conductive foil.

[0035] It should be noted that if Figure 1 , 3 As shown in Figures 4 and 5, the first conductive layer 12 constitutes the upper side of the composite electrode tab 1, and the second conductive layer 13 constitutes the lower side of the composite electrode tab 1. Among the multiple composite electrode tabs 1, the second conductive layer 13 of the composite electrode tab 1 of the upper layer is arranged opposite to and close to the first conductive layer 12 of the lower layer. The conductive sheets 2 are all attached to the first conductive layer 12, that is, the conductive sheets 2 are attached to the upper side of the composite electrode tab 1.

[0036] During the film making process, it is necessary to press a plurality of composite tabs 1 along the thickness direction so that two adjacent composite tabs 1 are pressed together. In this solution, Figure 1 , 3 As shown, the position of the composite pole ear 1 of the bottom layer is kept unchanged, and the composite pole ear 1 of the upper layer is pressed downward by kneading. Since there are gaps between the multiple composite pole ears 1 stacked, the composite pole ear 1 of the upper layer will be close to the composite pole ear 1 of the bottom layer in the thickness direction, so that after pressing, the multiple composite pole ears 1 are located at the position of the composite pole ear 1 of the bottom layer. At the same time, the multiple composite pole ears 1 will drive the conductive sheet 2 in the length direction (i.e. Figure 1 The composite pole tabs 1 are misaligned in the X direction (in the X direction), and the misalignment degree of the composite pole tab 1 of the upper layer is greater than the misalignment degree of the composite pole tab 1 of the lower layer, so as to form a stepped structure 3 on one side of the conductive sheet 2. In this way, the multiple composite pole tabs 1 can be electrically connected by welding the stepped structure 3 formed by multiple conductive sheets 2.

[0037] In this way, by connecting the conductive sheet 2 on one side of the composite pole ear 1, the conductivity of the external electrical connection of the composite pole ear 1 is enhanced, the internal resistance of the battery is reduced, and the temperature rise at the pole ear is reduced. In addition, the processing technology is simple, which is conducive to reducing the quality risk caused by poor welding and improving the reliability of the product.

[0038] In this embodiment, in the length direction of the composite electrode ear 1 (i.e. Figure 1 In the X direction), the size of the conductive sheet 2 is larger than the size of the adjacent composite pole ear 1, and the adjacent composite pole ear 1 is the composite pole ear 1 on the upper side and lower layer of the conductive sheet 2, so that the conductive sheet 2 protrudes in the length direction of the composite pole ear 1, and then the two adjacent conductive sheets 2 can be fitted and connected, which is conducive to realizing the electrical connection of multiple conductive sheets 2, further improving the conductivity of the external electrical connection of the composite pole ear 1, and reducing the internal resistance of the battery.

[0039] In some preferred embodiments, the number of conductive sheets 2 is greater than the number of composite tabs 1. In addition to overlapping and electrically connecting conductive sheets 2 on the first conductive layer 12 of the composite tab 1, conductive sheets 2 are also overlapped and electrically connected on the second conductive layer 13 of the composite tab 1 (i.e., the conductive sheets 2 are arranged on the lower side of the composite tab 1 of the lowest layer), so that two adjacent conductive sheets 2 are respectively arranged on two side surfaces of the same composite tab 1 along the thickness direction. Since all conductive sheets 2 protrude in the length direction of the composite tab 1, the two sides of all composite tabs 1 can be electrically connected together through multiple conductive sheets 2, thereby improving the tab welding effect.

[0040] In some embodiments, the conductive sheet 2 is partially bonded to the side of the composite tab 1. Since the base layer 11 of the composite tab 1 is a polymer material such as PP, PET, etc., which is not conductive, if the entire area is welded, the internal resistance of the battery at the welding point will be too large. This solution adopts a partial bonding (i.e., non-full-area bonding) method, which can effectively reduce the welding area of ​​the polymer layer, thereby reducing the internal resistance of the battery and increasing the battery's current capacity.

[0041] In a specific solution, the bonding area between the conductive sheet 2 and the composite electrode tab 1 accounts for 6%-60% (preferably 30%-50%) of the overlapping area between the conductive sheet 2 and the composite electrode tab 1. Within this range, sufficient flow area can be ensured and the internal resistance of the battery can be reduced.

[0042] In some preferred embodiments, the plurality of composite tabs 1 are arranged in the length direction (i.e. Figure 3 The dimensions in the X direction of the plurality of composite tabs 1 are consistent. Thus, after the plurality of composite tabs 1 are meshed along the thickness direction, the offset dimensions of two adjacent composite tabs 1 are consistent, and have good consistency. Figure 3 In the X direction in the drawing, the sizes of the plurality of conductive sheets 2 are consistent. Thus, after the plurality of composite tabs 1 are meshed along the thickness direction, the sizes of the two adjacent conductive sheets 2 are consistent with the misalignment of the composite tabs 1, and the consistency is good.

[0043] During the production process, Figure 1 , 3 As shown, after the upper composite pole ear 1 is kneaded downward, the two adjacent composite pole ears 1 are in close contact through the conductive sheet 2, and the conductive sheet 2 is used to realize electrical connection and extraction. The heads of multiple composite pole ears 1 will form a gradient difference in the length direction. At the same time, the conductive sheet 2 forms a gradient difference in the length direction with the dislocation of the composite pole ear 1. Welding at the position where the gradient difference is formed can effectively reduce the area of ​​the polymer layer of the weld, thereby reducing the internal resistance of the battery. In addition, the length of the composite pole ear 1 can be increased by 0.5-1mm in sequence during the composite pole sheet die-cutting process or after the composite pole sheet is made, so as to realize the composite pole ear 1 in a gradient arrangement.

[0044] like Figure 5 , 6 As shown, in some embodiments, the electrode tab welding structure also includes a connecting sheet 5, and the connecting sheet 5 is welded to the conductive sheet 2, so as to be conductive with the conductive layer (the first conductive layer 12 and the second conductive layer 13) of each composite electrode tab 1. During the film making process, the connecting sheet 5 is connected through the adapter sheet, so as to realize the electrical connection of the conductive layers on both sides of the composite electrode tab 1. In this way, the current carrying capacity can be further improved by setting the connecting sheet 5. Specifically, the material of the connecting sheet 5 is set to copper or aluminum, and is set at the top layer of multiple composite electrode tabs 1, that is, the stepped structure 3 electrically connected to multiple conductive sheets 2.

[0045] In a specific embodiment, in the length direction of the composite electrode ear 1 (i.e. Figure 5 , 6 In the X direction of the composite electrode tab 1, the size of the overlapping area between each composite electrode tab 1 and the connecting sheet 5 is greater than or equal to 1 mm. Figure 6 In the Y direction in FIG. 1 , the connecting sheet 5 occupies at least 10% of the size of the composite tab 1. The thickness of the conductive sheet 2 is set to 0.05-0.3 mm.

[0046] The embodiment of the present application provides a battery, including a tab welding structure, which is the tab welding structure in the above embodiment. In this way, by connecting the conductive sheet 2 on one side of the composite tab 1, the conductivity of the composite tab 1 for external electrical connection is enhanced, the internal resistance of the battery is reduced, and the temperature rise at the tab is reduced. In addition, the processing technology is simple, which is conducive to reducing the quality risk caused by poor welding and improving the reliability of the product.

[0047] The battery includes a pole piece, which has a coating area 4 and a tab area, and a conductive sheet 2 is arranged in the tab area, and the interval between the conductive sheet 2 and the coating area 4 is greater than or equal to 0.5 mm. In this way, the conductive sheet 2 can be separated from the active material of the coating area 4, thereby improving the stability of the structure.

[0048] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0049] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0050] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0051] 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 readily apparent to those skilled in the art, and the general principles defined herein may 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 widest scope consistent with the principles and novel features disclosed herein.

[0052] 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 used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0053] The above description has been given for the purpose of illustration and description. In addition, this description is not intended 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. A tab welding structure, characterized in that: include: A tab group, comprising a plurality of composite tabs (1) stacked in layers, each of the composite tabs (1) comprising a base layer (11) and a first conductive layer (12) and a second conductive layer (13) respectively located on both sides of the base layer (11) in a thickness direction; A plurality of conductive sheets (2), wherein the conductive sheets (2) overlap with and are electrically connected to the first conductive layer (12) of the composite tab (1); The plurality of composite pole tabs (1) are pressed together along the thickness direction and pressed together at the position of the bottommost composite pole tab (1), so that the plurality of conductive sheets (2) are displaced along with the plurality of composite pole tabs (1) and a stepped structure (3) is formed on one side of the plurality of conductive sheets (2).

2. The electrode tab welding structure according to claim 1, characterized in that: In the length direction of the composite electrode tab (1), the size of the conductive sheet (2) is larger than the size of the composite electrode tab (1) adjacent thereto.

3. The electrode tab welding structure according to claim 1, characterized in that: The two adjacent conductive sheets (2) are respectively arranged on two side surfaces of the same composite electrode tab (1) along the thickness direction.

4. The electrode tab welding structure according to claim 1, characterized in that: The conductive sheet (2) is partially bonded to the side surface of the composite electrode tab (1).

5. The electrode tab welding structure according to claim 4, characterized in that: The bonding area between the conductive sheet (2) and the composite electrode tab (1) accounts for 6% to 60% of the overlapping area between the conductive sheet (2) and the composite electrode tab (1).

6. The electrode tab welding structure according to claim 1, characterized in that: include: The connecting sheet (5) is electrically connected to at least one of the conductive layers of each of the composite tabs (1).

7. The electrode tab welding structure according to claim 6, characterized in that: In the length direction of the composite electrode lug (1), the size of the overlapping area between each composite electrode lug (1) and the connecting sheet (5) is greater than or equal to 1 mm; in the width direction of the composite electrode lug (1), the connecting sheet (5) occupies at least 10% of the size of the composite electrode lug (1); and the thickness of the conductive sheet (2) is set to 0.05-0.3 mm.

8. The electrode tab welding structure according to claim 1, characterized in that: The multiple composite tabs (1) have consistent dimensions in the length direction; And / or, in the length direction of the plurality of composite tabs (1), the plurality of conductive sheets (2) have the same size.

9. A battery, comprising a tab welding structure, characterized in that: The tab welding structure is the tab welding structure according to any one of claims 1 to 8.

10. The battery according to claim 9, characterized in that It comprises a pole piece, the pole piece having a coating area (4) and a pole lug area, the conductive sheet (2) being arranged in the pole lug area, and the interval between the conductive sheet (2) and the coating area (4) being greater than or equal to 0.5 millimeters.

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