Composite current collector tab connecting structure not easy to separate

Abstract

The utility model discloses a composite current collector tab connecting structure not easy to separate, which comprises a composite current collector and metal foils connected to one end of the composite current collector, the outer side width of the edge of the composite current collector is larger than the inner side width, and the metal foils are arranged on the upper surface and the lower surface of the composite current collector. The metal foils on the two surfaces are welded, and a welding area surrounds the edge of the composite current collector, so that the welding area of the metal foils and the edge of the composite current collector are mutually blocked. According to the utility model, the firmness of connection between the composite current collector and the metal foil can be obviously improved, and the metal foil can stably clamp the composite current collector due to mutual blocking between the welding area and the composite current collector, so that the problem that the composite current collector is easy to separate in the prior art is effectively solved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and more specifically to a composite current collector pole ear connection structure that is not easy to separate. Background Art

[0002] Batteries generally include positive and negative electrode sheets and positive and negative electrode current collectors, etc. The positive and negative electrode current collectors are respectively connected to the positive and negative electrode sheets and collect current to the positive and negative electrodes. Batteries generally use a composite current collector, which includes a polymer layer, and the upper and lower surfaces of the polymer layer are provided with metal coatings. The composite current collector has the advantages of small thickness and high safety performance. Since the upper and lower metal coatings of the composite current collector are not connected, the upper and lower metal coatings need to be connected through a conductive sheet and connected to the pole ears.

[0003] At present, the connection between the composite current collector and the pole ear is to use two layers of metal pole ears to clamp one side of a layer of composite current collector, and then weld the multiple layers of metal pole ears to the positive pole ears or negative pole ears of the lithium battery respectively, so as to realize the connection between the composite current collector and the pole ears. This connection structure requires wrapping and welding two metal pole ears on one side of each composite current collector, which will increase the weight of the battery and reduce the energy density of the battery.

[0004] A composite current collector unit and a composite current collector tab connection structure with Chinese patent publication number CN218274649U is disclosed, in which a first foil is arranged at a first connection portion, a second foil is arranged at a second connection portion, and the first foil and the second foil are alternately connected on the upper and lower surfaces of the composite current collector to reduce the weight of the battery. However, the first foil and the second foil are overlapped on the surface of the composite current collector and are easily detached from the composite current collector. Utility Model Content

[0005] In order to overcome the problem that the first foil and the second foil are overlapped on the surface of the composite current collector and are easily separated from the composite current collector, the utility model provides a composite current collector tab connection structure that is not easy to separate.

[0006] The technical solution of the utility model is as follows:

[0007] A composite current collector tab connection structure that is not easy to detach comprises a composite current collector and a metal foil connected to one end of the composite current collector, wherein the outer width of the edge of the composite current collector is greater than the inner width, the metal foil is arranged on the upper and lower surfaces of the composite current collector, the metal foils on both surfaces are welded, and the welding area surrounds the edge of the composite current collector so that the welding area of ​​the metal foil and the edge of the composite current collector block each other to prevent detachment.

[0008] According to the above solution of the utility model, the cross section of the edge of the composite current collector is an inverted cone.

[0009] According to the above-mentioned solution of the utility model, the cross section of the edge of the composite current collector is a major arc shape.

[0010] According to the above-mentioned solution of the utility model, the cross section of the edge of the composite current collector is in a "convex" shape.

[0011] According to the above-mentioned solution of the utility model, an electrode coating layer is provided on the surface of at least one side of the composite current collector.

[0012] According to the above-mentioned solution of the utility model, the electrode coating layer includes one of a positive electrode active material layer and a negative electrode active material layer.

[0013] The utility model according to the above solution further comprises a pole ear, wherein the pole ear is located at an end of the metal foil away from the composite current collector.

[0014] According to the utility model of the above scheme, the composite current collector laminate has multiple layers, metal foil is provided in two adjacent layers of the composite current collector, and the two adjacent layers of the composite current collector are electrically connected to the electrode tab through the metal foil.

[0015] According to the utility model of the above solution, the welding method of the metal foil is ultrasonic welding or resistance welding.

[0016] According to the above-mentioned solution of the utility model, the thickness of the metal foil is 1-15 μm.

[0017] The utility model according to the above scheme has the beneficial effect that the utility model has a composite current collector pole ear connection structure that is not easy to detach. By setting the edge of the composite current collector to a large tail and a small head shape, after the composite current collector is welded to the metal foil, the metal foil welding area and the composite current collector block each other, the metal foil can clamp the composite current collector more firmly, and the connection between the composite current collector and the metal foil can be more firm, thereby effectively connecting the upper and lower surfaces of the composite current collector. The utility model can significantly improve the connection firmness between the composite current collector and the metal foil, the metal foil can stably clamp the composite current collector, and effectively solves the problem of easy detachment in the prior art; because the welding area and the composite current collector block each other, the metal foil can be clamped on the composite current collector, and the stability of the composite current collector is improved, thereby improving the overall performance and safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the utility model;

[0019] Figure 2 A top view of an embodiment of the utility model;

[0020] Figure 3 A top view of another embodiment of the utility model;

[0021] Figure 4 A top view of another embodiment of the utility model;

[0022] Figure 5 A top view of yet another embodiment of the present utility model;

[0023] Figure 6 It is a schematic diagram of the structure of the composite current collector of the utility model;

[0024] Figure 7 A top view of an embodiment of the composite current collector of the utility model;

[0025] Figure 8 A top view of another embodiment of the composite current collector of the utility model;

[0026] Fig. 9 A top view of another embodiment of the composite current collector of the utility model;

[0027] Fig.10 It is a top view of another embodiment of the composite current collector of the utility model.

[0028] In the drawings, the reference numerals are as follows:

[0029] 1. Composite current collector; 11. Electrode coating layer; 12. Through hole; 2. Metal foil; 3. Tab; 4. Welding area. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0031] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present utility model are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. Terms such as "setting" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "bottom", etc. are based on the directions or positions shown in the drawings, which are only for the convenience of description and cannot be understood as limitations on the present technical solution.

[0032] like Figure 1-Figure 10 As shown, in order to overcome the problem that the existing first foil and the second foil are overlapped on the surface of the composite current collector and are easy to detach from the composite current collector, the present embodiment provides a composite current collector pole ear connection structure that is not easy to detach, by setting the edge of the composite current collector 1 to a shape with a large tail and a small head, or punching a hole 12 at the edge of the composite current collector 1, after the composite current collector 1 is welded to the metal foil 2, the welding area of ​​the metal foil 2 and the composite current collector 1 block each other, the metal foil 2 can clamp the composite current collector 1 more firmly, and the connection between the composite current collector 1 and the metal foil 2 can be more firm, thereby effectively connecting the upper and lower surfaces of the composite current collector 1.

[0033] The composite current collector structure of the utility model can significantly improve the connection firmness between the composite current collector 1 and the metal foil 2, and the metal foil 2 can stably clamp the composite current collector 1, effectively solving the problem of easy separation in the prior art. Secondly, since the welding area and the composite current collector 1 block each other, the metal foil 2 can be clamped on the composite current collector 1, and the stability of the composite current collector 1 is improved, thereby improving the overall performance and safety of the battery.

[0034] The composite current collector structure also has the advantages of easy manufacturing and low cost. Through simple process adjustments, large-scale production and application can be achieved.

[0035] Specifically, it includes a composite current collector 1 and a metal foil 2 connected to one end of the composite current collector 1, the outer width of the edge of the composite current collector 1 is greater than the inner width or the edge of the composite current collector 1 is provided with a through hole 12; the metal foil 2 is arranged on the upper and lower surfaces of the composite current collector 1, the metal foils 2 on both sides are welded, and the welding area surrounds the edge of the composite current collector 1, so that the welding area of ​​the metal foil 2 clamps the edge of the composite current collector 1.

[0036] When the outer width of the edge of the composite current collector 1 is greater than the inner width, the welding area of ​​the metal foil 2 is mainly located in the outer area of ​​the edge of the composite current collector 1, or includes a small area of ​​the edge of the composite current collector 1. Since the outer width of the edge of the composite current collector 1 is greater than the inner width, the edge of the composite current collector 1 and the welding area of ​​the metal foil 2 are mutually connected, and the metal foil 2 can clamp the composite current collector 1, thereby achieving conduction between the upper and lower surfaces of the composite current collector 1. Since the edge of the composite current collector 1 is in a shape with a large tail and a small head, and the width near the middle of the composite current collector 1 is small, it is mutually connected with the welding area of ​​the metal foil 2 after being clamped, and will not fall off.

[0037] When the through hole 12 is punched on the edge of the composite current collector 1, the welding area of ​​the metal foil 2 is mainly the edge area of ​​the composite current collector 1 and the area at the through hole 12, or includes a small part of the edge area of ​​the composite current collector 1 and a small part of the area at the through hole 12 on the edge of the composite current collector 1. By welding the metal foil 2 at the edge of the composite current collector 1 and the metal foil 2 at the through hole 12 of the composite current collector 1, that is, the metal foil 2 is fixed at the through hole 12 of the composite current collector 1, the composite current collector 1 is firmly clamped and is not easy to fall off. The composite current collector 1 is clamped between the two metal foils 2, thereby realizing the conduction between the upper and lower surfaces of the composite current collector 1.

[0038] In one embodiment, the cross section of the edge of the composite current collector 1 is an inverted cone. The cross section of the edge of the composite current collector 1 is designed to be an inverted cone, and the edge width of the composite current collector 1 gradually decreases toward the inside. This special shape of the edge can further strengthen the connection between the composite current collector 1 and the welding area of ​​the metal foil 2, prevent the composite current collector 1 from moving, and thus improve the stability between the composite current collector 1 and the metal foil 2. The inverted cone cross-sectional design can make the metal foil 2 better fit on the edge of the composite current collector 1, reduce the gaps and air bubbles that appear during the welding process, and further improve the welding quality.

[0039] In one embodiment, the cross section of the edge of the composite current collector 1 is a major arc, and its central angle is greater than 200°. The major arc design can better adapt to the edge shape of the composite current collector 1, reduce the stress concentration phenomenon generated after welding, and thus improve the stability and reliability of the overall structure. The major arc cross-sectional design can also reduce the heat concentration during the welding process, avoiding poor welding or material damage caused by excessive heat.

[0040] In one embodiment, the cross-section of the edge of the composite current collector 1 is in the shape of a "convex" character. There is a raised portion on the cross-section, which can not only form a hook with the welding area of ​​the metal foil 2, but also increase the contact area of ​​the welding area, so that the metal foil 2 can better fit on the edge of the composite current collector 1, reducing the gaps and air bubbles that may appear during the welding process, thereby improving the stability of the welding. The "convex"-shaped cross-sectional design can also optimize the flow guidance effect. The current can flow more smoothly through the welding area between the composite current collector 1 and the metal foil 2. 4 not only reduces the resistance, but also helps to improve the conductivity and overall performance of the battery.

[0041] In one embodiment, at least one surface of the composite current collector 1 is coated with an electrode coating layer 11. The electrode coating layers 11 on the upper and lower surfaces of the composite current collector 1 may be the same or different.

[0042] The electrode coating layer 11 includes one of a positive electrode active material layer and a negative electrode active material layer. The positive electrode active material layer is mainly composed of elements such as lithium, cobalt, and nickel, and has high electrical conductivity and electrochemical activity. The negative electrode active material layer is mainly composed of materials such as graphite and lithium titanate, and has high capacity and stability.

[0043] When coating the electrode coating layer 11, a suitable coating process is selected, such as physical vapor deposition, chemical vapor deposition, electroplating, spraying, etc., to achieve uniform coating of the electrode coating layer 11 on the surface of the composite current collector 1. At the same time, according to the properties of the electrode coating layer 11 and the characteristics of the composite current collector 1, a suitable coating thickness and coating method are selected to ensure good bonding between the electrode coating layer 11 and the composite current collector 1.

[0044] By coating the surface of the composite current collector 1 with the electrode coating layer 11, the conductivity and welding effect of the composite current collector 1 can be further improved. At the same time, the presence of the electrode coating layer 11 can also enhance the corrosion resistance and stability of the composite current collector 1, thereby improving the reliability and service life of the overall structure.

[0045] In one embodiment, a tab 3 is further included, and the tab 3 is located at one end of the metal foil 2 away from the composite current collector 1. The main function of the tab 3 is to connect the composite current collector 1 with an external circuit to transfer current. By arranging the tab 3 at the far end of the metal foil 2, the conductive property of the metal foil 2 can be better utilized, and welding directly on the edge of the composite current collector 1 is avoided, thereby reducing the difficulty of welding and improving the stability of welding.

[0046] The composite current collector 1 has multiple layers, and metal foils 2 are provided between two adjacent layers of the composite current collector 1 . The two adjacent layers of the composite current collector 1 are electrically connected to the tabs 3 through the metal foils 2 .

[0047] In one embodiment, the metal foil 2 is welded by ultrasonic welding or resistance welding. The principle of ultrasonic welding is to use the heat generated by high-frequency vibration to melt the metal foil 2, and then use the pressure generated by vibration to tightly combine the metal foil 2. Compared with traditional welding methods, ultrasonic welding can complete the welding operation in a shorter time, thereby improving production efficiency. The contact area of ​​the metal foil 2 in the molten state of ultrasonic welding is larger, and the surface of the metal foil 2 after welding is relatively flat, and the conductivity of the welding area is better. Resistance welding uses the resistance heat generated by the current passing through the weldment and the contact point as a heat source to locally heat the weldment, and pressurizes the weldment for welding.

[0048] The thickness of the metal foil 2 is 1-15 μm. By adopting the above technical solution, the metal foil 2 is a 1-15 μm foil, and the thickness of the metal foil 2 is small, thereby reducing the thickness of the composite current collector 1 and improving the energy density of the battery. The weight of the metal foil 2 is low, which can reduce the weight of the battery.

[0049] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to the utility model.

[0050] The above is an exemplary description of the utility model patent in conjunction with the accompanying drawings. It is obvious that the implementation of the utility model patent is not limited to the above-mentioned method. As long as various improvements are made by adopting the method concept and technical solution of the utility model patent, or the concept and technical solution of the utility model patent are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. A composite current collector tab connection structure that is not easy to separate, comprising a composite current collector and a metal foil connected to one end of the composite current collector, characterized in that: The outer width of the edge of the composite current collector is greater than the inner width. The metal foil is arranged on the upper and lower surfaces of the composite current collector. The metal foils on both sides are welded, and the welding area surrounds the edge of the composite current collector so that the welding area of ​​the metal foil and the edge of the composite current collector block each other.

2. The composite current collector tab connection structure that is not easily separated according to claim 1, characterized in that: The cross section of the edge of the composite current collector is in the shape of an inverted cone.

3. The composite current collector tab connection structure that is not easily separated according to claim 1, characterized in that: The cross section of the edge of the composite current collector is a major arc shape.

4. The composite current collector tab connection structure that is not easily separated according to claim 1, characterized in that: The cross section of the edge of the composite current collector is in a "convex" shape.

5. A composite current collector tab connection structure that is not easily detached according to any one of claims 1 to 4, characterized in that: An electrode coating layer is provided on at least one side of the surface of the composite current collector.

6. The composite current collector tab connection structure that is not easily separated according to claim 5, characterized in that: The electrode coating layer includes one of a positive electrode active material layer and a negative electrode active material layer.

7. The composite current collector tab connection structure that is not easily separated according to claim 1, characterized in that: It also includes a pole ear, which is located at one end of the metal foil away from the composite current collector.

8. The composite current collector tab connection structure that is not easily separated according to claim 7, characterized in that: The composite current collector laminate has multiple layers, and metal foil is provided in two adjacent layers of the composite current collectors. The composite current collectors in two adjacent layers are electrically connected to the tabs through the metal foil.

9. The composite current collector tab connection structure that is not easily separated according to claim 1, characterized in that: The thickness of the metal foil is 1-15 μm.

10. The composite current collector tab connection structure that is not easily separated according to claim 1, characterized in that: The metal foil is welded by ultrasonic or resistance welding.

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