Collecting plate for cylindrical lithium battery and cylindrical lithium battery monomer

Abstract

The current collecting plate comprises a positive current collecting plate, the positive current collecting plate comprises a circular pole lug welding area, a current collecting handle and a circular end cover welding area, a central liquid injection through hole and a first auxiliary hole are formed in the end face of the circular pole lug welding area, and a second auxiliary hole is formed in the current collecting handle. According to the utility model, the plurality of first auxiliary holes are distributed in the circular tab welding area and are uniformly distributed in the internal space of the battery, so that the injection and infiltration of electrolyte and the discharge of gas in the battery are facilitated, the distribution positions of the first auxiliary holes do not occupy the functional area of the circular tab welding area, and the first auxiliary holes can be arranged according to a welding mode; and welding processes such as spot welding, wire welding or ring welding are met. And the second auxiliary hole is formed in the current collecting handle, so that the over-current area transmitted from the battery pole group to the end cover assembly can be reduced, and the current collecting handle can be quickly fused and the current output can be cut off when the battery is in short circuit or thermal runaway.

Description

Technical Field

[0001] This utility model belongs to the field of lithium battery structure, specifically relating to a current collector for a cylindrical lithium battery and a cylindrical lithium battery cell. Background Technology

[0002] As the performance requirements for lithium batteries become increasingly stringent, traditional lithium batteries, which employ a single tab or a small number of tabs, suffer from uneven current distribution, high internal resistance, and problems such as localized overheating, capacity decay, and reduced cycle life. Cylindrical full-tab lithium batteries, due to their advantages of good rate performance, low cost, and good safety, are becoming increasingly popular. In the manufacturing process of cylindrical full-tab batteries, the protruding current collectors at both ends of the electrode assembly are connected to the positive and negative current collectors, which are then connected to the cell casing and end cap assembly structure to deliver electrical energy to the outside.

[0003] For cylindrical all-tab lithium-ion batteries, the current collector has many functions and requirements. It needs to be firmly welded, compatible with electrolyte injection and easy wetting and penetration, prevent short circuit between the positive current collector and the casing, and address cost issues. Currently used positive current collectors only have a central through hole for electrolyte injection. Moreover, after a short circuit or thermal runaway occurs, the current collector handle melts and takes a long time to break. In short, there is still room for further improvement in the current collector. Utility Model Content

[0004] This invention provides a current collector for cylindrical lithium batteries and a cylindrical lithium battery cell, which addresses the shortcomings of the prior art.

[0005] The technical solution adopted in this utility model is as follows:

[0006] A current collector for a cylindrical lithium battery includes a positive current collector, which comprises a circular tab welding area, a current collector stalk, and a circular end cap welding area. The end face of the circular tab welding area has a central electrolyte injection through-hole and a first auxiliary hole, and the current collector stalk has a second auxiliary hole. The first auxiliary hole, evenly distributed around the central electrolyte injection through-hole, facilitates better electrolyte wetting and penetration into the electrode assembly. Furthermore, the first auxiliary hole does not occupy the functional space of the circular tab welding area. Besides improving electrolyte injection efficiency, it also helps to expel gas generated inside the battery. The second auxiliary hole on the current collector stalk reduces its overcurrent area, allowing the current collector stalk to melt more quickly in the event of a short circuit or thermal runaway, cutting off the current output and preventing greater safety hazards, thus providing safety assurance.

[0007] In a preferred embodiment of this invention, the side end where the circular electrode welding area connects to the collector handle is a straight end, and a bending notch is provided at the position where the straight end connects to the collector handle. The bending notch facilitates the bending of the collector handle.

[0008] As a preferred embodiment of this utility model, the second auxiliary hole is provided along the extension direction of the collector handle, that is, along the flow direction of the collector handle.

[0009] As a preferred embodiment of this utility model, it also includes a negative electrode current collector, which can be a rectangular or circular current collector. The negative electrode current collector only has a shell welding area, and can be rectangular or circular. The rectangular current collector can be directly made from rolled material, cut to the specified size according to process requirements, with no material waste, saving material costs, improving utilization rate and production efficiency. The circular current collector has a larger contact area, which can reduce the battery's internal resistance and heating rate, and obtain better high-rate output performance.

[0010] In a preferred embodiment of this invention, the negative electrode current collector has a raised / lowered welding point at its center. The raised / lowered welding point is designed to improve the weldability of resistance welding and enhance the stability of the battery structure; other slight deformations that facilitate welding can also be used.

[0011] As a preferred embodiment of this utility model, functional holes or slots are provided at the edge or redundant space of the negative electrode current collector. Without affecting the manufacturing and performance of the negative electrode current collector, the functional holes or slots facilitate the gripping and positioning of the production equipment during battery production, and also provide error prevention and orientation protection.

[0012] This utility model also provides a cylindrical lithium battery cell, including the aforementioned current collector for cylindrical lithium batteries.

[0013] As a preferred embodiment of this utility model, it further includes a housing, an insulating ring between the positive current collector and the housing, a battery electrode assembly inside the housing, and an end cap assembly on the top of the housing. The insulating ring protects the positive current collector from internal short circuits when the battery is deformed.

[0014] As a preferred embodiment of the present invention, the battery electrode assembly includes a first electrode tab at the top and a second electrode tab at the bottom. The positive electrode current collector is disposed above the first electrode tab, the circular electrode tab welding area is welded to the first electrode tab, and the circular end cap welding area is welded to the end cap assembly. The negative electrode current collector is disposed below the second electrode tab and is welded to the second electrode tab.

[0015] This invention features multiple first auxiliary holes evenly distributed within the circular tab welding area of ​​the battery. This facilitates electrolyte injection and wetting, as well as the venting of internal gases. Furthermore, the placement of these first auxiliary holes does not encroach on the functional area of ​​the circular tab welding area and can be arranged according to the welding method, accommodating spot welding, wire welding, or ring welding. The second auxiliary hole in the current collector reduces the current-carrying area from the battery electrode assembly to the end cap assembly, allowing for faster melting of the current collector and interruption of current output in the event of a short circuit or thermal runaway. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the positive current collector of this utility model.

[0018] Figure 2 This is a schematic diagram of the rectangular negative electrode current collector of this utility model.

[0019] Figure 3 This is a schematic diagram of the circular negative electrode current collector of this utility model.

[0020] Figure 4 This is a schematic diagram of the structure of the battery cell of this utility model.

[0021] Figure 5 This is an exploded view of the battery cell of this utility model with the outer casing omitted. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] This utility model provides an embodiment of a current collector for a cylindrical lithium battery, including a positive current collector 1 and a negative current collector 2.

[0024] like Figure 1As shown, the positive electrode current collector 1 includes a circular tab welding area 11, a current collector stalk 12, and a circular end cap welding area 13. The end face of the circular tab welding area 11 is provided with a central liquid injection through hole 111 and a first auxiliary hole 112. The first auxiliary hole is a circular punch with a small diameter. The first auxiliary hole does not affect the structure and welding function of the circular tab welding area. The shape, number, and distribution position of the punch can be selected according to the welding process. This not only does not affect the manufacturing process and process design, but also facilitates the wetting of the electrolyte inside the battery and the discharge of gas after expansion, thereby improving the safety performance of the battery.

[0025] The side end where the circular tab welding area 11 connects to the current collector 12 is a straight end 113. A bending notch 114 is provided at the connection point between the straight end 113 and the current collector 12, facilitating bending of the current collector. Furthermore, the current collector 12 is provided with a second auxiliary hole 121. The second auxiliary hole 121 is located along the extension direction of the current collector, i.e., along the current flow direction. This reduces the current flow area of ​​the current collector, allowing it to melt more quickly in the event of a battery short circuit or thermal runaway, cutting off the current output and preventing greater safety hazards, thus providing safety assurance.

[0026] The positive current collector can be made of industrial pure aluminum, aluminum alloy, or aluminum-based composite materials. It is formed by stamping, etching, laser cutting and other forming processes. While taking into account conductivity, lightweight and stability, it can also reflect the advantages of its design.

[0027] The negative electrode current collector 2 is made of copper, copper-nickel composite, or other copper-based materials, and is formed using stamping, etching, and laser cutting processes. It is suitable for high energy density and high safety requirements, and combines the advantages of high precision, low internal resistance, and large-scale production efficiency. The negative electrode current collector only has a shell welding area and uses a rectangular or circular current collector. Furthermore, a raised / lowered welding point 21 is located at the center of the negative electrode current collector 2. The raised / lowered welding point is designed to improve the solderability of resistance welding, enhance the stability of the battery structure, and can also incorporate other slight deformations that facilitate welding.

[0028] When using a rectangular collector panel, such as Figure 2 As shown, it can be made directly from rolled material and cut to the specified size according to process requirements. There is no waste in material utilization, which can save material costs, improve utilization rate and production efficiency. The circular current collector has a larger contact area, which can reduce the battery internal resistance and heat generation rate, and obtain better high-rate output performance.

[0029] When a circular collector plate is used, such as Figure 3As shown, a raised / concave welding point 21 is provided at the center of the outer casing welding area 22, and a functional hole 23 is provided on the surface of the outer casing welding area 22 outside the raised / concave welding point. This functional hole does not affect the original performance of the negative electrode current collector, and is intended to facilitate the gripping and positioning of the production equipment during battery production, as well as to prevent mistaken orientation. Of course, functional holes or functional grooves can also be provided at the edge of the negative electrode current collector 2.

[0030] This utility model also provides an embodiment of a cylindrical lithium battery cell, such as... Figure 4 and 5 As shown, it includes a positive current collector 1, a negative current collector 2, a housing 3, a battery electrode assembly 5, and an end cap assembly 6. The end cap assembly 6 serves as the positive lead-out end of the battery and is rigidly fitted with the metal housing 3. The end cap assembly 6 is connected to the battery electrode assembly 5 through the positive current collector 1, so that it maintains stable electrochemical performance and current output capability inside.

[0031] The outer casing 3 is the negative terminal of the battery. It can be made of nickel-plated steel strip or aluminum alloy and formed by die stamping. At the same time, the surface of the casing should be plated, such as nickel plating, which can further increase conductivity, rust prevention and corrosion resistance. The outer casing 3 is closed at one end and open at the other end. It is a thin-walled cylindrical metal component with an internal cavity. The negative current collector 2 is located at the closed end of the outer casing and is located below the battery electrode group 5 and welded to the battery electrode group 5.

[0032] An insulating ring 4 is provided between the positive current collector 1 and the outer casing 3 to further prevent the first electrode tab 51 and the positive current collector from contacting the outer casing 3. The insulating ring 4 can also be replaced with a structure formed by wrapping with insulating tape, achieving the same effect. A battery electrode assembly 5 is provided inside the outer casing 3, which is formed by winding a positive electrode, a negative electrode, and heat insulation.

[0033] The top of the outer casing 3 is equipped with an end cap assembly 6. An inwardly oriented groove is machined at a suitable position below the opening of the outer casing 37. The lower edge of the groove presses against the electrode assembly to prevent displacement. The end cap assembly 6 is pressed into the opening of the outer casing, allowing it to be horizontally positioned along the upper edge of the inner groove. The opening of the casing can be mechanically bent inward at an angle of 90° or greater. The end cap assembly 6 and the outer casing 3 together form a sealed space for the battery cell, preventing leakage of internal electrolyte or the entry of external air and moisture into the battery. An insulating ring protects the positive current collector, preventing internal short circuits when the battery deforms.

[0034] In this embodiment, the battery electrode assembly 5 includes a first tab 51 at the top and a second tab 52 at the bottom. The positive or negative electrode of the battery electrode assembly 5 has an uncoated current collector extending upwards as the first tab 51, while a current collector of the opposite polarity extends downwards as the second tab 51. A positive current collector 1 is disposed above the first tab 51, and a circular tab welding area 11 is welded to the first tab 51. Electrical connection is achieved by keeping the current collector and the tab concentric and tightly fitted, and by welding.

[0035] The current collector 12 is bent toward the circular tab welding area, so that the circular end cap welding area 13 is welded to the end cap assembly 6. Both the positive current collector and the end cap assembly have insulation protection to prevent short circuits between the positive and negative electrodes. The insulating pad of the positive current collector and the insulating ring of the end cap assembly can be made of polypropylene (PP), polybutylene terephthalate (PBT), soluble polytetrafluoroethylene (PFA), polyphenylene sulfide (PPS), or other insulating and electrolyte-resistant materials and modified materials, either by punching or injection molding.

[0036] The negative electrode current collector 2 is located below the second electrode tab 52 and is welded to the second electrode tab 52.

[0037] The battery electrode assembly is connected by welding the positive electrode current collector and the negative electrode current collector, and then connected to the positive and negative electrode leads represented by the end cap assembly and the shell, with insulation protection in between. After the electrolyte injection and encapsulation process, the battery cell is completed, forming a complete cylindrical full-tab lithium battery.

[0038] The battery cell structure of this utility model can meet various production processes, improve production efficiency, facilitate electrolyte injection and wetting, and allow gas generated inside the battery to be discharged. At the same time, it can also ensure its safety and fully leverage its advantages of low internal resistance, high energy output, and excellent thermal management.

[0039] In this specification, the terms "an embodiment," "example," "specific example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A current collector for a cylindrical lithium battery, comprising a positive current collector (1), characterized in that: The positive electrode current collector (1) includes a circular electrode tab welding area (11), a current collector handle (12) and a circular end cap welding area (13). The end face of the circular electrode tab welding area (11) is provided with a central liquid injection through hole (111) and a first auxiliary hole (112), and the current collector handle (12) is provided with a second auxiliary hole (121).

2. The current collector for a cylindrical lithium battery according to claim 1, characterized in that: The side end of the circular electrode welding area (11) connected to the collector handle (12) is a straight end (113), and a bending notch (114) is provided at the position where the straight end (113) is connected to the collector handle (12).

3. The current collector for a cylindrical lithium battery according to claim 2, characterized in that: The second auxiliary hole (121) is provided along the extension direction of the collector handle.

4. The current collector for a cylindrical lithium battery according to any one of claims 1-3, characterized in that: It also includes a negative electrode collector plate (2), which is a rectangular collector plate or a circular collector plate.

5. The current collector for a cylindrical lithium battery according to claim 4, characterized in that: The negative electrode current collector (2) is provided with a concave-convex welding point (21) at its center.

6. The current collector for a cylindrical lithium battery according to claim 5, characterized in that: The negative electrode collector (2) is provided with functional holes or functional slots at its edge or in redundant space.

7. A cylindrical lithium battery cell, characterized in that: Includes the current collector for cylindrical lithium batteries as described in claim 5.

8. The cylindrical lithium battery cell according to claim 7, characterized in that: It also includes a housing (3), an insulating ring (4) is provided between the positive electrode current collector (1) and the housing (3), a battery electrode assembly (5) is provided inside the housing (3), and an end cap assembly (6) is provided on the top of the housing (3).

9. The cylindrical lithium battery cell according to claim 8, characterized in that: The battery electrode assembly (5) includes a first electrode tab (51) at the top and a second electrode tab (52) at the bottom. The positive electrode current collector (1) is disposed above the first electrode tab (51), the circular electrode tab welding area (11) is welded to the first electrode tab (51), and the circular end cap welding area (13) is welded to the end cap assembly (6). The negative electrode current collector (2) is disposed below the second electrode tab (52) and welded to the second electrode tab (52).

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