Cylindrical lithium battery

Abstract

This invention relates to the field of lithium battery technology and provides a cylindrical lithium battery, comprising: a cylindrical casing having an open end and a closed end, wherein a first through hole is formed at the center of the end face of the closed end; a cell assembly disposed within the casing, including a first electrode near the closed end and a second electrode near the open end, the first electrode and the second electrode having different electrical polarities; a first current collector disposed within the casing and connected to the first electrode of the cell assembly, wherein a boss extending from the first through hole to the outside of the casing is provided at the center of the first current collector; a first electrode lead-out end cap disposed outside the casing and connected to the boss; and a second electrode lead-out end cap disposed at the open end of the casing, connecting the second electrode of the cell assembly and the casing, wherein the second electrode lead-out end cap and the casing are sealed together. The cylindrical lithium battery provided by this invention avoids battery self-discharge and internal short circuits caused by metal dust generated during the battery sealing process.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, and more specifically, relates to a cylindrical lithium battery. Background Technology

[0002] Lithium-ion batteries boast high energy density, long cycle life, excellent rate performance and safety, and are environmentally friendly, making them a crucial energy source for modern electronic products and electric vehicles. Furthermore, steel-cased cylindrical lithium-ion batteries offer standardized models, a high degree of automation in production, good battery consistency, and convenient assembly design, making them the preferred choice for electronic products and electric vehicles, leading to their increasingly widespread application.

[0003] Existing cylindrical lithium batteries typically include a casing with openings at both ends, a cell assembly, a positive terminal cap, and a negative terminal cap. The cell assembly is located inside the casing, the negative terminal cap is located at one opening of the casing and connected to the negative terminal of the cell assembly, and the positive terminal cap is located at the other opening of the casing and connected to the positive terminal of the cell assembly. When packaging cylindrical lithium-ion batteries, it is usually necessary to perform a grooving process on the battery casing. When the casing is used to fix the positive terminal cap, the grooving can provide a point of force to fix the positive terminal cap. However, there is a risk that nickel powder may fall during the grooving process and cause a short circuit inside the battery. Summary of the Invention

[0004] The purpose of this invention is to provide a cylindrical lithium battery to solve the technical problem of internal short circuits caused by nickel powder falling off during the grooving process of existing cylindrical lithium batteries.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a cylindrical lithium battery is provided, comprising: a cylindrical housing having an open end and a closed end opposite to the open end, wherein a first through hole is provided at the center of the end face of the closed end; a cell assembly disposed within the housing, including a first electrode near the closed end and a second electrode near the open end, wherein the first electrode and the second electrode have different electrical properties; a first current collector disposed within the housing and connected to the first electrode of the cell assembly, wherein a boss extending from the first through hole to the outside of the housing is provided at the center of the first current collector; a first electrode lead-out end cap disposed outside the housing and connected to the boss; and a second electrode lead-out end cap disposed at the open end of the housing, connecting the second electrode of the cell assembly and the housing, wherein the second electrode lead-out end cap is sealed to the housing.

[0006] Furthermore, a second current collector is provided between the second electrode lead-out end cap and the second electrode terminal of the battery cell assembly.

[0007] Furthermore, a second through hole for injecting electrolyte is provided on the protrusion.

[0008] Furthermore, the first electrode lead-out end cap has a groove corresponding to the protrusion for positioning the first electrode lead-out end cap.

[0009] Furthermore, the cylindrical lithium battery also includes a first sealing element, which is disposed between the first current collector and the closed end of the housing.

[0010] Furthermore, the first electrode end is provided with multiple concave surfaces, and the first current collector is provided with multiple protrusions protruding towards the concave surfaces, with the multiple protrusions inserted into the multiple concave surfaces for fixation.

[0011] Furthermore, the opening end of the housing is provided with a flange facing the inside of the housing, and the flange fixes the second electrode lead-out end cap.

[0012] Furthermore, a receiving ring is formed between the side wall of the housing and the flange, and a connecting ring fixed to the receiving ring is provided on the second electrode lead-out end cap.

[0013] Furthermore, a second sealing element is provided between the second electrode lead-out end cap and the flange.

[0014] Furthermore, the boss is integrally stamped with the first manifold; or, the boss is welded to the center of the first manifold using laser welding.

[0015] The cylindrical lithium battery provided by this invention, compared with the prior art, does not have the grooved sealing structure of traditional cylindrical batteries. The outer surface of the cylindrical shell has no inward or outward deformation. The open end of the cylindrical lithium battery is sealed to the shell through a second electrode lead-out end cap to achieve shell encapsulation. In the traditional cylindrical battery groove and sealing process, metal deformation will cause metal dust to contaminate the inside of the battery. The structure of this invention completely avoids the generation of metal dust during the battery sealing process, thereby avoiding battery self-discharge and internal short circuit caused by metal dust generated during the battery sealing process. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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 the present invention. 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 structure of a cylindrical lithium battery provided in an embodiment of the present invention;

[0018] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0019] Figure 3 for Figure 1 A magnified view of a section at point B in the middle;

[0020] Figure 4 for Figure 1 A magnified view of a section at point C.

[0021] The following are the labeling elements in the figure:

[0022] 1-Housing; 11-Closed end; 111-First through hole; 12-Open end; 122-Flanged edge; 123-Receiving ring; 2-Cell assembly; 21-First electrode terminal; 211-Concave surface; 22-Second electrode terminal; 3-First current collector; 31-Boss; 311-Second through hole; 32-Protrusion; 4-First electrode lead-out end cap; 41-Groove; 42-Connecting ring; 5-Second electrode lead-out end cap; 6-First seal; 7-Second seal. Detailed Implementation

[0023] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0024] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0025] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] Please see Figure 1 The cylindrical lithium battery provided by the present invention will now be described. The cylindrical lithium battery includes: a cylindrical housing 1 having an open end and a closed end opposite to the open end, wherein a first through hole 111 is provided at the center of the end face of the closed end; a cell assembly 2 disposed inside the housing 1, including a first electrode 21 near the closed end 11 and a second electrode 22 near the open end 12, wherein the first electrode 21 and the second electrode 22 have different electrical properties; a first current collector 3 disposed inside the housing 1 and connected to the first electrode 21 of the cell assembly 2, wherein a boss 31 extending from the first through hole 111 to the outside of the housing 1 is provided at the center of the first current collector 3; a first electrode lead-out end cap 4 disposed outside the housing 1 and connected to the boss 31; and a second electrode lead-out end cap 5 disposed at the open end 12 of the housing 1, connecting the second electrode 22 of the cell assembly 2 and the housing 1, wherein the second electrode lead-out end cap 5 is sealed to the housing 1. In specific implementation, the battery cell assembly 2 is a wound core formed by winding a positive electrode sheet, a negative electrode sheet, and a separator. The housing 1 can be a steel shell. The boss 31 can be integrally stamped with the first current collector 3, or it can be welded to the center of the first current collector 3 by laser welding. The specific setting can be selected according to actual needs. The first electrode 21 can be a positive electrode, and correspondingly, the second electrode 22 can be a negative electrode; the first electrode 21 can also be a negative electrode, and correspondingly, the second electrode 22 can be a positive electrode. There is no limitation here, and the setting can be selected according to actual needs. For ease of understanding, the following explanation uses the example of the first electrode 21 being a positive electrode and the second electrode 22 being a negative electrode. The first electrode 21 is connected to the first current collector 3. The positive electrode of the first electrode 21 is guided to the first current collector 3. Since the center of the first current collector 3 is provided with a boss 31 extending from the first through hole 111 to the outside of the housing 1, and the first electrode lead-out end cover 4 is connected to the boss 31, the positive electrode on the first current collector 3 is guided to the first electrode lead-out end cover 4 outside the housing 1 through the boss 31. The second electrode lead-out end cover 5 connects the second electrode 22 and the housing 1. Therefore, the negative electrode of the second electrode 22 is led out to the housing 1 through the second electrode lead-out end cover 5. At this time, the first electrode lead-out end cover 4 located outside the housing 1 and close to the closed end 11 of the housing 1 has a different electrode from the closed end 11 of the housing 1. Thus, the positive electrode and the negative electrode can be led out at the same end of the housing 1, which is convenient for the installation and maintenance of cylindrical lithium batteries in electric vehicles. Similarly, when the first electrode 21 is the negative electrode and the second electrode 22 is the positive electrode, the positive and negative electrodes are drawn out in opposite directions, which will not be elaborated here.

[0028] The cylindrical lithium battery provided by this invention, compared with the prior art, does not have the grooved sealing structure of traditional cylindrical batteries. The outer surface of the cylindrical shell 1 has no inward or outward deformation. The open end 12 of the cylindrical lithium battery is sealed to the shell 1 through the second electrode lead-out end cap 5 to achieve the encapsulation of the shell 1. In the traditional cylindrical battery groove and sealing process, due to metal deformation, metal dust will be generated and contaminate the inside of the battery. The structure of this invention completely avoids the generation of metal dust during the sealing process of the cylindrical lithium battery, thereby avoiding battery self-discharge and internal short circuit caused by metal dust generated during the sealing process of the cylindrical lithium battery.

[0029] In one embodiment, a second current collector (not shown) is provided between the second electrode lead-out end cap 5 and the second electrode terminal 22 of the cell assembly 2. Specifically, for cylindrical lithium batteries where the second current collector and the second electrode lead-out end cap 5 are integrated, the second electrode lead-out end cap 5 is directly connected to the second electrode terminal 22 of the cell assembly 2; for cylindrical lithium batteries where the second current collector and the second electrode lead-out end cap 5 are separate, the second electrode lead-out end cap 5 is connected to the second electrode terminal 22 of the cell assembly 2 through the second current collector. The specific configuration can be selected according to actual needs.

[0030] In one embodiment, in conjunction with reference to Figure 2 The boss 31 has a second through hole 311 for injecting electrolyte. By providing the second through hole 311, when it is necessary to inject electrolyte into the cell assembly 2, the electrolyte can be injected into the cell assembly 2 through the second through hole 311.

[0031] In one embodiment, the first electrode lead-out end cap 4 has a groove 41 corresponding to the boss 31 for positioning the first electrode lead-out end cap 4. By providing the groove 41 corresponding to the boss 31 on the first electrode lead-out end cap 4, and by the cooperation between the groove 41 and the boss 31, the first electrode lead-out end cap 4 can be easily positioned during installation, thus improving the stability of the installation process.

[0032] In one embodiment, the cylindrical lithium battery further includes a first sealing element 6, which is disposed between the first current collector 3 and the closed end 11 of the housing 1. Specifically, since the electrodes on the housing 1 and the first electrode lead-out end cap 4 are different from those on the closed end 11 of the housing 1, that is, the electrodes on the first current collector 3 and the closed end 11 of the housing 1 are also different, the first sealing element 6, disposed between the first current collector 3 and the closed end 11 of the housing 1, not only achieves sealing between the first current collector 3 and the closed end 11 of the housing 1, but also insulates the first current collector 3 from the housing 1, preventing short circuits in the cylindrical lithium battery.

[0033] In one embodiment, the first electrode 21 is provided with multiple concave surfaces 211, and the first current collector 3 is provided with multiple protrusions 32 protruding towards the concave surfaces 211. The multiple protrusions 32 are inserted into the multiple concave surfaces 211 for fixation. In specific implementation, multiple protrusions 32 are provided on the first current collector 3, and the protrusions 32 protrude towards the concave surfaces 211, so that they can be inserted into the concave surfaces 211 for fixation. This allows the first current collector 3 to be better positioned and fixed with the end face of the cell assembly 2, which is convenient for laser welding, improves the production efficiency of the product, thereby reducing the production cost of the product and improving the market competitiveness of the product. Compared with the existing battery electrode end face being flattened to form a welding plate, the battery electrode end face corresponding to the protrusions 32 provided on the first current collector 3 is flattened for easy welding. The other parts of the end face of the cell assembly 2 are still in an upright state, and the electrolyte is more easily penetrated, improving the electrolyte penetration efficiency. Preferably, each protrusion 32 extends along the radial direction of the first current collector 3, that is, it is set in a reflective manner from the center of the first current collector 3 toward the circumference of the first current collector 3, so that it is more stable and reliable when it is in contact with the end face of the battery cell assembly 2.

[0034] In one embodiment, in conjunction with reference to Figure 3 The opening end 12 of the housing 1 is provided with a flange 122 facing inwards, which fixes the second electrode lead-out end cover 5. By providing a flange 122 facing inwards at the opening end 12 of the housing 1, not only can the second electrode lead-out end cover 5 be fixed, but it can also seal the opening end 12 of the housing 1. There are various ways to connect the second electrode lead-out end cover 5 to the cell assembly 2. For example, the connection method between the first current collector 3 and the cell assembly 2 described above can be used. Specifically, multiple concave surfaces 211 can be provided at one end of the cell assembly 2 near the second electrode lead-out end cover 5, and protrusions that cooperate with the multiple concave surfaces 211 can be provided on the second electrode lead-out end cover 5. The protrusions are inserted into the concave surfaces 211 to fix it. Of course, other methods can also be used to connect the second electrode lead-out end cover 5 to the cell assembly 2. Those skilled in the art can choose the appropriate method according to actual needs.

[0035] Furthermore, in conjunction with reference Figure 4 In one specific embodiment of the cylindrical lithium battery provided by this utility model, a receiving ring 123 is formed between the side wall of the housing 1 and the flange 122, and a connecting ring 42 fixed to the receiving ring 123 is provided on the second electrode lead-out end cap 5. There are various ways to fix the connecting ring 42 to the receiving ring 123. For example, the connecting ring 42 can be welded inside the receiving ring 123, or the connecting ring 42 can be interference-fitted or snap-fitted to the receiving ring 123, as long as it can achieve the goal of fixing the connecting ring 42 to the receiving ring 123. Of course, it is understood that the housing 1 can also be directly welded to the second electrode lead-out end cap 5 through the flange 122 to achieve the fixation between the two. Those skilled in the art can choose the appropriate setting according to actual needs.

[0036] In one embodiment, a second sealing element 7 is provided between the second electrode lead-out end cap 5 and the flange 122. The second sealing element 7 can isolate the internal space of the cylindrical lithium battery from the external space of the cylindrical lithium battery.

[0037] In one embodiment, the boss 31 is laser-welded to the first electrode lead-out end cap 4. By laser-welding the boss 31 to the first electrode lead-out end cap 4, the fixed connection between the boss 31 and the first electrode lead-out end cap 4 can be better guaranteed. At the same time, it can also seal the second through hole 311 for electrolyte filling, avoiding problems such as electrolyte leakage that affect the function of the cylindrical lithium battery due to loosening of the connection between the boss 31 and the first electrode lead-out end cap 4 during use or transportation.

[0038] In one embodiment, the boss 31 is integrally stamped with the first collector plate 3; or, the boss 31 is welded to the center of the first collector plate 3 by laser welding.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cylindrical lithium battery, characterized in that, include: A cylindrical shell has an open end and a closed end opposite to the open end, and a first through hole is provided at the center of the end face of the closed end; A battery cell assembly, disposed within the housing, includes a first electrode near the closed end and a second electrode near the open end, wherein the first electrode and the second electrode have different electrical properties; wherein, the battery cell assembly is a wound core formed by winding a positive electrode sheet, a negative electrode sheet, and a separator. The first current collector is disposed inside the housing and connected to the first electrode of the battery cell assembly. The center of the first current collector is provided with a boss extending from the first through hole to the outside of the housing. The first electrode lead-out end cap is located outside the housing and connected to the boss; the positive electrode on the first current collector is guided to the first electrode lead-out end cap outside the housing through the boss; A second electrode lead-out end cap is disposed at the open end of the housing, connecting the second electrode terminal of the battery cell assembly and the housing. The negative electrode of the second electrode terminal is led out to the housing through the second electrode lead-out end cap, and the second electrode lead-out end cap is sealed to the housing. At this time, the first electrode lead-out end cap located outside the housing and close to the closed end of the housing has a different electrode from the closed end of the housing, and can lead out the positive and negative electrodes at the same end of the housing. The first electrode is provided with multiple concave surfaces, and the first current collector is provided with multiple protrusions protruding towards the concave surfaces. The multiple protrusions are inserted into the multiple concave surfaces for fixation, and each protrusion is arranged in a reflective manner with respect to the center of the first current collector in the circumferential direction of the first current collector. The protrusion is provided with a second through hole for injecting electrolyte; The first electrode lead-out end cap has a groove corresponding to the protrusion, which is used to position the first electrode lead-out end cap. The opening end of the housing is provided with a flange facing the inside of the housing, and the flange fixes the second electrode lead-out end cap; A receiving ring is formed between the side wall of the housing and the flange, and a connecting ring fixed to the receiving ring is provided on the second electrode lead-out end cap; A second sealing element is provided between the second electrode lead-out end cap and the flange; Wherein, the first electrode is a positive electrode, and the second electrode is a negative electrode; or, The first electrode is a negative electrode, and the second electrode is a positive electrode.

2. The cylindrical lithium battery as described in claim 1, characterized in that, A second current collector is provided between the second electrode lead-out end cap and the second electrode terminal of the battery cell assembly.

3. The cylindrical lithium battery as described in claim 1, characterized in that, The cylindrical lithium battery further includes a first sealing element, which is disposed between the first current collector and the closed end of the housing.

4. The cylindrical lithium battery as described in claim 1, characterized in that, The boss is integrally stamped with the first manifold; or, the boss is welded to the center of the first manifold by laser welding.

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