Cylindrical secondary battery and method for manufacturing the same

Abstract

According to one embodiment of the present disclosure, a cylindrical secondary battery is provided, in which an electrode assembly having a positive electrode / separator / negative electrode structure is built into a cylindrical battery can, the cylindrical secondary battery comprising: a first insulating layer, the first insulating layer being installed at an upper end portion of the electrode assembly and having a first through hole for an electrode tab to pass through; and a second insulating layer, the second insulating layer being installed at an upper end portion of the first insulating layer and having a second through hole formed corresponding to a center position of the electrode assembly.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2019-0012233 filed on January 30, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0003] The present disclosure relates to a cylindrical secondary battery and a method for manufacturing the same, and more particularly, to a cylindrical secondary battery for aligning positions of electrode tabs and a method for manufacturing the same. Background Art

[0004] In modern society, with the daily use of portable devices such as mobile phones, notebook computers, camcorders and digital cameras, technological development in fields related to the above-mentioned mobile devices has become active, and the demand for the development of secondary batteries used in portable devices has also increased.

[0005] The secondary battery includes: an electrode assembly consisting of a positive electrode, a separator and a negative electrode; and a housing that seals the electrode assembly and the electrolyte. According to their structural differences, such secondary batteries can be divided into cylindrical secondary batteries, prismatic secondary batteries and pouch-type secondary batteries.

[0006] A cylindrical secondary battery may include: an electrode assembly consisting of a positive electrode, a separator, and a negative electrode; a can that accommodates the electrode assembly and has an opening at an upper end; and a cap assembly that covers the upper end of the can. Typically, in the electrode assembly, the positive electrode is connected to a positive electrode tab, which may be welded to the cap assembly at the upper end of the opening, and the negative electrode is connected to a negative electrode tab, which may be welded to the bottom surface of the can.

[0007] Figure 1 is a plan view of an electrode assembly before winding to explain the positions of electrode tabs in a conventional secondary battery. Figure 2 It is shown Figure 1 A perspective view of a structure in which an electrode assembly is wound.

[0008] like Figure 1 As shown in , in a conventional secondary battery, the electrode tab 21 before winding is biased to the outside, rather than the center of the electrode assembly 10. In this case, when current flows through the electrode, the resistance may vary due to the difference in current density. In view of this, attempts have been made to move the position of the electrode tab 21 to the center of the electrode assembly 10, but there is a problem of deterioration in workability during the manufacturing process of the secondary battery.

[0009] In this regard, refer to Figure 2 , when Figure 1When the position of the electrode tab 21 in the electrode assembly 10 is moved to the center of the electrode assembly 10, Figure 2 Compared with the conventional electrode tab 21 of the electrode assembly 10, the position of the electrode tab 21 is wound Figure 1 The position of the electrode tab 21 shown in the electrode assembly 10 is changed to the position of the outermost electrode tab 21' as shown in the arrow direction in the jelly roll structure. Therefore, during the assembly process of the secondary battery, there are various process problems, such as interference of a beading holder in a beading process, interference of a syringe holder in an injection process, and stability problems caused by reverse alignment of the tabs.

[0010] Therefore, there is a need to improve the problem of deterioration in workability and output performance due to the position of an electrode tab formed on an electrode assembly of a secondary battery. Summary of the invention

[0011] Technical issues

[0012] The embodiments of the present disclosure are proposed to solve the above-mentioned problems of the previously proposed methods. Therefore, the purpose of the present disclosure is to provide a cylindrical secondary battery and a manufacturing method thereof that attempt to improve the difficulties in the process caused by the position of the electrode tab extending to the upper end of the electrode assembly during the manufacturing process of a conventional cylindrical secondary battery, and that can improve the processability by adjusting the position of the electrode.

[0013] However, the problems to be solved by the embodiments of the present disclosure are not limited to the above-mentioned problems, and various extensions can be made within the scope of the technical concept included in the present disclosure.

[0014] Technical Solution

[0015] According to one embodiment of the present disclosure, a cylindrical secondary battery is provided, in which an electrode assembly having a positive electrode / separator / negative electrode structure is built into a cylindrical battery can, the cylindrical secondary battery comprising: a first insulating layer, which is installed at the upper end of the electrode assembly and has a first through hole for an electrode tab to pass through; and a second insulating layer, which is installed at the upper end of the first insulating layer and has a second through hole formed corresponding to the center position of the electrode assembly.

[0016] The electrode tab passing through the first through hole may be bent so as to pass through the second through hole.

[0017] The electrode tab passing through the second through hole may have a shape disposed perpendicularly to the second insulating layer and protruding from the center of the electrode assembly.

[0018] The first via hole is formed at a position other than a center of the first insulating layer, and the first via hole and the second via hole may not overlap each other.

[0019] The first through hole and the second through hole may have a straight through hole structure respectively.

[0020] According to one embodiment of the present disclosure, there is provided a method for manufacturing a cylindrical secondary battery, in which an electrode assembly having a positive electrode / separator / negative electrode structure is built into a cylindrical battery can, the method comprising the following steps: installing a first insulating layer on the upper end portion of the electrode assembly, and then allowing an electrode tab connected to the electrode assembly to extend upward through a first through hole formed in the first insulating layer; bending the electrode tab passing through the first through hole; and installing a second insulating layer at the upper end of the first insulating layer, wherein the bent electrode tab passes through a second through hole formed on the second insulating layer.

[0021] The electrode tab passing through the second through hole may have a shape disposed perpendicularly to the second insulating layer and protruding from the center of the electrode assembly.

[0022] The bending of the electrode tab may include bending at the first through hole and the second through hole, respectively.

[0023] The second through hole may be disposed at a center of the second insulating layer.

[0024] The method of manufacturing a cylindrical secondary battery may further include: winding the electrode assembly into a jelly roll shape; and disposing the wound electrode assembly inside a battery can.

[0025] Beneficial Effects

[0026] According to an embodiment of the present disclosure, the electrode tab portion connected to the electrode maintains a position for high output, and at the same time, by folding the electrode tab using multiple insulating layers, the position of the electrode tab portion extending to the upper end of the electrode assembly can be close to the center of the electrode assembly, thereby improving the assembly workability of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a plan view of an electrode assembly before winding to explain the positions of electrode tabs in a conventional secondary battery.

[0028] Figure 2 It is shown Figure 1 A perspective view of a structure in which an electrode assembly is wound.

[0029] Figure 3 is a diagram illustrating a cylindrical secondary battery according to one embodiment of the present disclosure.

[0030] Figures 4 to 7 is a perspective view illustrating a method of manufacturing a cylindrical secondary battery according to other embodiments of the present disclosure. DETAILED DESCRIPTION

[0031] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. The present disclosure can be modified in various different ways and is not limited to the embodiments set forth herein.

[0032] Parts irrelevant to the description will be omitted to clearly describe the present disclosure, and like reference numerals denote like elements throughout the application.

[0033] In addition, in the drawings, for the convenience of description, the size and thickness of each element are arbitrarily shown, and the present disclosure is not necessarily limited to those shown in the drawings. In the drawings, for the sake of clarity, the thickness of layers, regions, etc. are exaggerated. In the drawings, for the convenience of description, the thickness of some layers and regions is exaggeratedly shown.

[0034] Furthermore, it will be understood that when an element such as a layer, film, region, or plate is referred to as being "on" or "above" another element, the element may be directly on the other element or there may be intervening elements. Conversely, when an element is referred to as being "directly on" another element, this means that there are no other intervening elements. Furthermore, the term "on..." or "above..." refers to being disposed on or above a reference portion, and does not necessarily mean being disposed on the upper end of the reference portion facing in the opposite direction of gravity.

[0035] Furthermore, throughout the application, when a part is referred to as “comprising” a certain component, it means that the part may further include other components, without excluding the other components, unless otherwise specified.

[0036] Figure 3 is a diagram illustrating a cylindrical secondary battery according to one embodiment of the present disclosure.

[0037] Reference Figure 3 A cylindrical secondary battery according to one embodiment of the present disclosure includes: an electrode assembly 100; an electrode tab 110 extending from the electrode assembly 100; a first insulating layer 120 having a first through hole 122 formed therein, and the electrode tab 110 passes through the first insulating layer 120 through the first through hole 122; and a second insulating layer 130 having a second through hole 132 formed therein.

[0038] The electrode assembly 100 is formed as a positive electrode / separator / negative electrode structure, and such an electrode assembly 100 can be built into a cylindrical battery can. The first insulating layer 120 and the second insulating layer 130 are installed at the upper end of the electrode assembly 100, and the electrode tab 110 passes through the first through hole 122 and then passes through the second through hole 132. At this time, according to the present embodiment, the first through hole 122 and the second through hole 132 are respectively formed at different positions in the first insulating layer 120 and the second insulating layer 130. The second through hole 132 can be formed closer to the center of the electrode assembly 100 than the first through hole 122. Here, as Figure 2 As shown in , the center of the electrode assembly 100 may refer to the center of a circle that appears when the electrode assembly 100 is cut in a horizontal direction.

[0039] The electrode tab 110 passing through the first through hole 122 may be bent to pass through the second through hole 132 , and may have a shape disposed perpendicular to the second insulating layer 130 and protruding from the center of the electrode assembly 100 .

[0040] The shapes of the first through hole and the second through hole may have a straight through hole structure, however these shapes may be variously modified.

[0041] The first through hole 122 is formed at any position except the center of the first insulating layer 120, and the first through hole 122 and the second through hole 132 may be formed so as not to overlap each other based on the vertical direction. Also, the shapes of the first through hole 122 and the second through hole 132 are not limited to Figure 3 In other embodiments, the first through hole 122 and the second through hole 132 may be elliptical holes having a size through which the electrode tab 110 may pass.

[0042] The first insulating layer 120 is located at the upper end of the electrode assembly 100 to prevent Figure 3 In the embodiment of the present invention, the first insulating layer 120 is formed of an insulating material. The first insulating layer 120 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material. The second insulating layer 130 is formed of an insulating material.

[0043] The electrode tab 110 may be a positive electrode tab.

[0044] Hereinafter, a method of manufacturing a cylindrical secondary battery according to the present embodiment will be described.

[0045] A method for manufacturing a secondary battery according to the present embodiment is a method for manufacturing a cylindrical secondary battery in which an electrode assembly having a positive electrode / separator / negative electrode structure is built into a cylindrical battery can, the method comprising the following steps: winding the electrode assembly into a jelly roll shape; installing a first insulating layer on the upper end of the electrode assembly, and then allowing the electrode tab to extend upward through a first through hole formed in the first insulating layer; bending the electrode tab passing through the first through hole twice to be arranged perpendicular to the first insulating layer; and installing a second insulating layer on the upper end of the first insulating layer so that the bent electrode tab passes through a second through hole formed on the second insulating layer.

[0046] After the step of winding the electrode assembly into a jelly-roll shape, the method may further include disposing the electrode assembly wound into the jelly-roll shape inside a battery can.

[0047] In the following, reference will be made to Figures 4 to 7 The method of manufacturing the cylindrical secondary battery according to the present embodiment is described in more detail. Figures 4 to 7 is a perspective view illustrating a method of manufacturing a cylindrical secondary battery according to other embodiments of the present disclosure.

[0048] like Figure 4 As shown in FIG. 2 , the electrode tab 110 protrudes at the upper end of the electrode assembly 100 disposed inside the battery can 200, wherein it can be seen that the position of the electrode tab 110 is offset to the outside rather than the center of the electrode assembly 100 in a manner similar to that in a conventional secondary battery. Although not shown, the electrode assembly 100 according to the present embodiment may be in a jelly roll shape.

[0049] Figure 5 is a diagram showing a case where the first insulating layer 120 is mounted on Figure 4 1 is a diagram of the shape of the upper end of the electrode assembly 100. The first through hole 122 is not formed at the center of the first insulating layer 120, that is, it is formed at a position other than the center of the electrode assembly 100. This causes the first through hole 122 to be biased toward the outside so that the protruding electrode tab 110 passes through.

[0050] Figure 6 1 is a diagram showing the bent shape of the electrode tab 110 that has passed through the first through hole 122. This is to position the remaining portion of the electrode tab 110 that extends outwardly from the electrode assembly 100 at the center of the electrode assembly 100, wherein the electrode tab 110 may be vertically bent twice and is disposed to extend vertically from the center of the electrode assembly 100.

[0051] Next, Figure 71 is a diagram in which the second insulating layer 130 is installed on the upper end of the first insulating layer 120, wherein the bent electrode tab 110 passes through the second through hole 132 of the second insulating layer 130. The second through hole 132 is formed in a portion corresponding to the central position of the electrode assembly 100, and finally the electrode tab 110 passing through the second through hole 132 has a shape perpendicular to the second insulating layer 130 and extending from the center of the electrode assembly 100.

[0052] As described above, the technical significance of the present disclosure is that by positioning the positive electrode tab at the center of the electrode assembly, interference from a beading holder, a syringe fixture, etc. is eliminated in the assembly process of the secondary battery, thereby improving workability, and by installing two insulators at the upper end of the electrode assembly, the insulation performance is improved to prevent phenomena such as short circuits, thereby improving stability. If the positive electrode tab is not located at the center of the electrode assembly based on the winding before, but is biased to either side, when current flows through the electrode, the resistance may change due to the difference in current density. Therefore, when the positive electrode tab is located at the center of the electrode assembly as in the embodiment of the present disclosure, the difference in current density is reduced than before, resulting in a reduction in resistance, thereby improving output characteristics.

[0053] Although the preferred embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present disclosure defined by the following claims also belong to the scope of rights.

Claims

1. A cylindrical secondary battery, in which an electrode assembly having a positive electrode / separator / negative electrode structure is built in a cylindrical battery can, the electrode assembly is provided with only one positive electrode tab connected to the positive electrode and only one negative electrode tab connected to the negative electrode, the cylindrical secondary battery comprising: a first insulating layer installed at an upper end of the electrode assembly and having a first through hole for an electrode tab to pass through; and a second insulating layer, the second insulating layer being installed at an upper end of the first insulating layer and having a second through hole formed corresponding to a central position of the electrode assembly, wherein the one electrode tab passing through the first through hole is bent so as to pass through the second through hole, wherein the one electrode tab passing through the second through hole has a shape that is disposed perpendicular to the second insulating layer and extends from the center of the electrode assembly, wherein the first through hole is formed at a position outside the center of the first insulating layer, and the first through hole and the second through hole do not overlap each other, wherein the one electrode tab is located at the center of the electrode assembly before winding, and The first insulating layer has only one through hole, namely, the first through hole. 2 . The cylindrical secondary battery according to claim 1 , wherein the first through hole and the second through hole respectively have a straight through hole structure.

3. A method for manufacturing a cylindrical secondary battery, in which an electrode assembly having a positive electrode / separator / negative electrode structure is built into a cylindrical battery can, the electrode assembly being provided with only one positive electrode tab connected to the positive electrode and only one negative electrode tab connected to the negative electrode, the method comprising the following steps before performing a crimping process: Installing a first insulating layer on the upper end of the electrode assembly, and then allowing an electrode tab connected to the electrode assembly to protrude upward through a first through hole formed in the first insulating layer; bending the one electrode tab passing through the first through hole; and installing a second insulating layer at an upper end of the first insulating layer, wherein the bent electrode tab passes through a second through hole formed on the second insulating layer, wherein the one electrode tab passing through the second through hole has a shape that is disposed perpendicular to the second insulating layer and extends from the center of the electrode assembly, wherein the one electrode tab is located at the center of the electrode assembly before winding, and The first insulating layer has only one through hole, namely, the first through hole. 4 . The method of manufacturing a cylindrical secondary battery according to claim 3 , wherein the bending of the one electrode tab includes bending at the first through hole and the second through hole, respectively. 5 . The method of manufacturing a cylindrical secondary battery according to claim 3 , wherein the second through hole is provided at the center of the second insulating layer.

6. The method for manufacturing a cylindrical secondary battery according to claim 3, further comprising: winding the electrode assembly into a jelly roll shape; and The wound electrode assembly is disposed inside a battery can.

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