Cylindrical secondary battery and method for manufacturing the same

Abstract

To provide a cylindrical secondary battery and manufacturing method thereof capable of adjusting the position of an electrode tab to improve workability in order to improve the process difficulty caused by the position of the electrode tab protruding from the upper end of an electrode assembly in a manufacturing process of a cylindrical secondary battery.SOLUTION: A secondary battery in which an electrode assembly having a cathode / separator / negative structure is housed in a cylindrical battery can includes a first insulating layer 120 mounted on the upper end of an electrode assembly 100 and having a first through hole 122 through which an electrode tab penetrates, and a second insulating layer 130 mounted on the upper end of the first insulating layer and having a second through hole 132 formed to correspond to the central position of the electrode assembly.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of priority based on Korean Patent Application No. 10 - 2019 - 0012233, filed on January 30, 2019, and all of the contents disclosed in the document of the Korean patent application are incorporated herein by reference as part of this specification.

[0002] The present invention relates to a cylindrical secondary battery and a method for manufacturing the same, and more particularly, to a cylindrical secondary battery for aligning electrode tab positions and a method for manufacturing the same.

Background Art

[0003] In modern society, with the daily use of portable devices such as mobile phones, notebook computers, camcorders, and digital cameras, the development of technologies in fields related to these devices has become active, and the need for the development of secondary batteries used in portable devices is increasing.

[0004] A secondary battery includes an electrode assembly composed of a positive electrode, a separator, and a negative electrode, and an external case for sealing the electrode assembly with an electrolytic solution. Such a secondary battery can be classified into a cylindrical secondary battery, a prismatic secondary battery, and a pouch - type secondary battery according to structural differences.

[0005] A cylindrical secondary battery is composed of an electrode assembly including a positive electrode, a separator, and a negative electrode, a can for accommodating the electrode assembly and having an opening at the upper end, and a cap assembly covering the upper end of the can. Generally, in the electrode assembly, a positive electrode tab is connected to the positive electrode, the positive electrode tab is welded to the cap assembly at the upper end of the opening, a negative electrode tab is connected to the negative electrode, and the negative electrode tab can be welded to the bottom surface of the can.

[0006] FIG. 1 is a plan view before winding an electrode assembly to explain the positions of electrode tabs in a conventional secondary battery. FIG. 2 is a perspective view showing the structure of the wound electrode assembly of FIG. 1.

[0007] As shown in FIG. 1, in a conventional secondary battery, the electrode tab 21 before winding is not at the center of the electrode assembly 10 but is offset to the outside. In this case, when current flows through the electrode, the resistance can change due to the current density difference. Considering this, there have been attempts to move the position of the electrode tab 21 to the center of the electrode assembly 10, but there has been a problem that the workability deteriorates in the manufacturing process of the secondary battery.

[0008] Referring to FIG. 2 in connection with this, when the position of the electrode tab 21 shown by winding the electrode assembly 10 of FIG. 1 is moved to the center of the electrode assembly 10 in the electrode assembly 10 of FIG. 1, as shown in the first direction d1 in the jelly roll structure in the electrode assembly 10 of FIG. 2, the electrode tab 21' is located further outside compared to the position of the existing electrode tab 21. As a result, during the assembly process of the secondary battery, there are various problems in the manufacturing process such as interference of the beading holder in the beading process, interference of the liquid injection machine holder in the liquid injection process, and stability problems due to tab misalignment.

[0009] It is necessary to improve the problems that the workability and output performance are reduced due to the position of the electrode tab formed on the electrode assembly of the secondary battery.

Summary of the Invention

Problems to be Solved by the Invention

[0010] Embodiments of the present invention are proposed to solve the above-mentioned problems of the previously proposed methods. In the manufacturing process of a conventional cylindrical secondary battery, in order to improve the engineering difficulties caused by the position of the electrode tab protruding from the upper end of the electrode assembly, the position of the electrode tab is adjusted to enhance the workability. The purpose is to provide a cylindrical secondary battery and its manufacturing method.

[0011] However, the problems to be solved by the embodiments of the present invention are not limited to the above-mentioned problems and can be variously extended within the scope of the technical idea included in the present invention.

Means for Solving the Problem

[0012] According to one embodiment of the present invention, in a cylindrical secondary battery, an electrode assembly having a positive electrode / separator / negative electrode structure is housed in a cylindrical battery can, and a first insulating layer having a first through-hole through which an electrode tab penetrates and is mounted on the upper end of the electrode assembly, and a second insulating layer having a second through-hole formed so as to correspond to the central position of the electrode assembly and mounted on the upper end of the first insulating layer are included.

[0013] The electrode tab that has passed through the first through-hole can be bent so as to pass through the second through-hole.

[0014] The electrode tab that has passed through the second through-hole can be arranged perpendicular to the second insulating layer and protrude from the center of the electrode assembly.

[0015] The first through-hole is formed at a position that is not the center of the first insulating layer, and the first through-hole and the second through-hole may not overlap with each other.

[0016] The first through-hole and the second through-hole may have a hole structure that penetrates linearly.

[0017] Also, according to another embodiment of the present invention, a method for manufacturing a cylindrical secondary battery is a method for manufacturing a secondary battery in which an electrode assembly having a positive electrode / separator / negative electrode structure is housed in a cylindrical battery can, including the steps of mounting a first insulating layer on the upper end of the electrode assembly so that an electrode tab connected to the electrode assembly penetrates through a first through-hole formed in the first insulating layer and protrudes upward, bending the electrode tab that has passed through the first through-hole, and mounting a second insulating layer on the upper end of the first insulating layer, wherein the bent electrode tab passes through a second through-hole formed in the second insulating layer.

[0018] The electrode tab that has passed through the second through-hole can be arranged perpendicular to the second insulating layer and protrude from the center of the electrode assembly.

[0019] The step of bending the electrode tab can include the steps of bending at the first through-hole and the second through-hole, respectively.

[0020] The second through-hole can be disposed at the center of the second insulating layer.

[0021] The method for manufacturing the cylindrical secondary battery can further include the step of winding the electrode assembly in a jelly roll form; and the step of disposing the wound electrode assembly inside the battery can.

Advantages of the Invention

[0022] According to an embodiment of the present invention, the electrode tab portion connected to the electrode can improve the assembly processability of the secondary battery by bringing the position of the electrode tab portion protruding from the upper end of the electrode assembly closer to the center of the electrode assembly by folding the electrode tab using a plurality of insulating layers while maintaining the position for high output.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Best Mode for Carrying Out the Invention

[0024] Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. The present invention can be realized in various different forms and is not limited to the embodiments described herein.

[0025] To clearly explain the present invention, parts that are unnecessary for the explanation are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

[0026] In addition, the size and thickness of each configuration shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to the places shown in the drawings. In the drawings, the thickness is enlarged to clearly show a plurality of layers and regions. And in the drawings, for convenience of explanation, the thickness of some layers and regions is exaggerated.

[0027] Also, when a part such as a layer, film, region, or plate is “on” another part, this includes not only the case where it is “directly on” another part but also the case where there are other parts in between. Conversely, when a part is “directly on” another part, it means that there are no other parts in between. Also, being “on” a reference part means being located above or below the reference part and does not necessarily mean being located “upward” in the opposite direction of gravity.

[0028] Also, throughout the specification, when a part “includes” a certain component, this means that other components can be further included without excluding other components, unless otherwise stated to the contrary.

[0029] FIG. 3 is a drawing showing a cylindrical secondary battery according to an embodiment of the present invention.

[0030] Referring to FIG. 3, a cylindrical secondary battery according to an embodiment of the present invention includes an electrode assembly 100, an electrode tab 110 protruding from the electrode assembly 100, a first insulating layer 120 in which a first through hole 122 through which the electrode tab 110 passes is formed, and a second insulating layer 130 in which a second through hole 132 is formed.

[0031] The electrode assembly 100 is formed in a positive electrode / separator / negative electrode structure, and such an electrode assembly 100 can be installed inside a cylindrical battery can. The first insulating layer 120 and the second insulating layer 130 are mounted on the upper end of the electrode assembly 100, and the electrode tab 110 passes through the second through hole 132 after passing through the first through hole 122. At this time, according to this embodiment, the positions where the first through hole 122 and the second through hole 132 are formed in the first insulating layer 120 and the second insulating layer 130 respectively are different from each other. The second through hole 132 can be formed closer to the center of the electrode assembly 100 than the first through hole 122. Here, the center of the electrode assembly 100 can be regarded as the center of the circle shown when the electrode assembly 100 is cut horizontally as viewed in FIG. 2.

[0032] The electrode tab 110 that has passed through the first through hole 122 is bent so as to pass through the second through hole 132, and the electrode tab 110 that has passed through the second through hole 132 can be arranged perpendicular to the second insulating layer 130 and protrude from the center of the electrode assembly 100.

[0033] The patterns of the first through hole 122 and the second through hole 132 can be a hole structure that penetrates linearly, but such patterns can be deformed in various ways.

[0034] The first through hole 122 is formed at a position that is not the center of the first insulating layer 120, and the first through hole 122 and the second through hole 132 can be formed so as not to overlap each other with respect to the vertical direction. The shapes of the first through hole 122 and the second through hole 132 are not limited to those shown in FIG. 3. As another embodiment, the first through hole 122 and the second through hole 132 can be elliptical holes having a size through which the electrode tab 110 can pass.

[0035] As shown in FIG. 3, the first insulating layer 120 is disposed at the upper end of the electrode assembly 100 to prevent a short circuit due to contact between the upper end of the electrode assembly 100 and the electrode tab 110 during the bending process of the electrode tab 110, and can be made of an insulating material. Further, the second insulating layer 130 is for bending the electrode tab 110 that has passed through the first through-hole 122 located at a portion other than the center of the electrode assembly 100 and positioning it at the center of the electrode assembly 100. The second through-hole 132 is disposed at the center of the second insulating layer 130, and it can be formed of an insulating material.

[0036] The electrode tab 110 described above can be a positive electrode tab.

[0037] Hereinafter, a method for manufacturing a cylindrical secondary battery according to this embodiment will be described.

[0038] The method for manufacturing a cylindrical secondary battery according to this embodiment is a method for manufacturing a secondary battery in which an electrode assembly having a positive electrode / separator / negative electrode structure is installed in a cylindrical battery can. The method includes winding the electrode assembly in a jelly roll form, mounting a first insulating layer on the upper end of the electrode assembly, passing an electrode tab through a first through-hole formed in the first insulating layer and protruding upward, bending the electrode tab that has passed through the first through-hole twice so that it is disposed perpendicular to the first insulating layer, and mounting a second insulating layer so that the bent electrode tab passes through a second through-hole formed in the second insulating layer mounted on the upper end of the first insulating layer.

[0039] After the step of winding the electrode assembly in a jelly roll form, the method can further include the step of disposing the electrode assembly wound in a jelly roll form inside the battery can.

[0040] Hereinafter, with reference to FIGS. 4 to 7, the method for manufacturing a cylindrical secondary battery according to this embodiment will be described in more detail. FIGS. 4 to 7 are perspective views showing a method for manufacturing a cylindrical secondary battery according to another embodiment of the present invention.

[0041] As shown in FIG. 4, an electrode tab 110 protrudes from the upper end of the electrode assembly 100 disposed inside the battery can 200. Here, it can be confirmed that the position of the electrode tab 110 is not at the center of the electrode assembly 100 but is biased outward, similar to that of an existing secondary battery. Although not shown, the electrode assembly 100 according to the present embodiment may be in a jelly roll form.

[0042] FIG. 5 is a drawing showing a state in which the first insulating layer 120 is mounted on the upper end of the electrode assembly 100 of FIG. 4. The first through-hole 122 is formed at a position that is not at the center of the first insulating layer 120, that is, not at the center of the electrode assembly 100. This is for passing through the electrode tab 110 that protrudes and is biased outward.

[0043] FIG. 6 is a drawing showing a state in which the electrode tab 110 passing through the first through-hole 122 is bent. It is for positioning the remaining portion of the electrode tab 110 that protrudes and is biased outward of the electrode assembly 100 at the center of the electrode assembly 100. The electrode tab 110 can be bent vertically twice so as to protrude vertically at the center of the electrode assembly 100.

[0044] Next, FIG. 7 is a drawing showing a state in which the second insulating layer 130 is mounted on the upper end of the first insulating layer 120. 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 at a portion corresponding to the center position of the electrode assembly 100. Finally, the electrode tab 110 passing through the second through-hole 132 has a form of protruding perpendicularly from the center of the electrode assembly 100 with respect to the second insulating layer 130.

[0045] As described above, by positioning the positive electrode tab at the center of the electrode assembly to eliminate interference from a beading holder, a liquid injection machine holder, etc. during the assembly process of the secondary battery, the workability is improved. By mounting two insulators on the upper end of the electrode assembly, the insulation is enhanced to double-prevent phenomena such as short circuits and improve stability. If the positive electrode tab is not positioned at the center of the electrode assembly with reference to before winding and instead biases to one side, the resistance can change due to the current density difference when current flows through the electrode. Therefore, when the positive electrode tab is positioned at the center of the electrode assembly as in the embodiment of the present invention, the current density difference is reduced and the resistance becomes lower than before, thereby resulting in an improvement in output characteristics.

[0046] The preferred embodiments of the present invention have been described in detail above. However, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the claims also belong to the scope of the present invention.

Claims

1. In a secondary battery in which an electrode assembly having a positive electrode / separator / negative electrode structure is housed in a cylindrical battery can, a first insulating layer mounted on the upper end of the electrode assembly and having a first through-hole through which an electrode tab penetrates; and a second insulating layer mounted on the upper end of the first insulating layer and having a second through-hole formed so as to correspond to the central position of the electrode assembly, the electrode tab that has passed through the first through-hole is bent so as to pass through the second through-hole, one of the electrode tabs is provided and is located at the center of the electrode assembly before winding, the electrode tab that has passed through the second through-hole is disposed perpendicular to the second insulating layer and protrudes from the center of the electrode assembly, a cylindrical secondary battery.

2. The cylindrical secondary battery according to claim 1, wherein the first through-hole is formed at a position that is not the center of the first insulating layer, and the first through-hole and the second through-hole do not overlap each other.

3. The cylindrical secondary battery according to claim 1 or 2, wherein the first through-hole and the second through-hole have a hole structure that penetrates linearly.

4. In a method for manufacturing a secondary battery in which an electrode assembly having a positive electrode / separator / negative electrode structure is housed in a cylindrical battery can, mounting a first insulating layer on the upper end of the electrode assembly so that an electrode tab connected to the electrode assembly penetrates through a first through-hole formed in the first insulating layer and protrudes upward; bending the electrode tab that has passed through the first through-hole; and mounting a second insulating layer on the upper end of the first insulating layer, the bent electrode tab passes through a second through-hole formed in the second insulating layer, one of the electrode tabs is provided and is located at the center of the electrode assembly before winding, the electrode tab that has passed through the second through-hole is disposed perpendicular to the second insulating layer and protrudes from the center of the electrode assembly, the second through-hole is disposed at the center of the second insulating layer, a method for manufacturing a cylindrical secondary battery.

5. The method for manufacturing a cylindrical secondary battery according to claim 4, wherein the step of bending the electrode tab includes steps of bending at the first through-hole and the second through-hole, respectively.

6. winding the electrode assembly in a jelly roll form; and further including the step of disposing the wound electrode assembly inside the battery can, the method for manufacturing a cylindrical secondary battery according to claim 4 or 5.

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