Cap assembly for cylindrical secondary battery and cylindrical secondary battery comprising same

Abstract

This specification relates to a cap assembly for a cylindrical secondary battery and a cylindrical secondary battery including the same.

Description

Technology Field

[0001] The present invention relates to a cap assembly for a cylindrical secondary battery and a cylindrical secondary battery including the same. Background Technology

[0002] Lithium-ion batteries are classified according to the shape of the battery case into cylindrical or prismatic batteries, in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries, in which the electrode assembly is housed in a pouch-type case made of aluminum laminate sheets. Among these, cylindrical batteries have the advantage of relatively high capacity and structural stability.

[0003] The cylindrical secondary battery is sealed by positioning a cap assembly on the top of an open cylindrical case, thereby isolating the exterior and interior of the cylindrical secondary battery. The gasket constituting the cap assembly also functions to ensure insulation between the top cap, which is connected to the positive tab of the electrode assembly, and the cylindrical case, which is connected to the negative tab.

[0004] A cap assembly for a cylindrical secondary battery consists of a top cap, a vent, a clamping gasket, a current interrupting member, and a bottom gasket. However, upon external impact, the vent is deformed due to the deformation of the cap assembly, and there is a problem in that the secondary battery easily short-circuits due to such deformation.

[0005] Therefore, there is a high need for cylindrical secondary batteries capable of preventing short circuits caused by external shocks. The problem to be solved

[0006] The present specification provides a cap assembly for a cylindrical secondary battery having strong resistance to deformation caused by external impact by improving the rigidity of the vent compared to conventional designs, and a cylindrical secondary battery including the same. means of solving the problem

[0007] One embodiment of the present specification provides a cap assembly for a cylindrical secondary battery, comprising: a top cap disposed on the upper part of the cap assembly; and a vent disposed on the lower part of the top cap, wherein the vent comprises a honeycomb layer comprising a plurality of hexagonal column structures.

[0008] Additionally, one embodiment of the present specification provides a cylindrical secondary battery comprising: a cylindrical can that accommodates an electrode assembly in a wound form with a separator placed between a positive electrode and a negative electrode; and a cap assembly coupled to an opening of the cylindrical can. Effects of the invention

[0009] The cap assembly according to the present invention has the effect of increasing the stability of the battery by increasing the rigidity of the vent without changing the existing material and having strong resistance to deformation from external impact, as the vent includes a honeycomb layer. Brief explanation of the drawing

[0010] FIG. 1 is a vertical cross-sectional view of a cylindrical secondary advance according to one embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of a cap assembly for a cylindrical secondary battery according to one embodiment of the present invention. FIG. 3 illustrates one embodiment of a vent included in the cap assembly of the present invention. Figure 4 illustrates a part of the honeycomb layer included in the above vent. Specific details for implementing the invention

[0011] The present specification will be described in more detail below.

[0012] In this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0013] In this specification, when it is said that a member is located "on" another member, this includes not only cases where a member is in contact with another member, but also cases where another member exists between the two members.

[0014] In this specification, when a part is described as being connected to another part, this includes not only cases where they are directly connected, but also cases where they are indirectly connected with other elements in between.

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. However, embodiments of the present invention may be modified in various forms, and the scope of the present invention is not limited to the embodiments described below. However, in describing the operating principles of preferred embodiments of the present invention in detail, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the essence of the present invention, such detailed description is omitted. Additionally, the same reference numerals are used for parts having similar functions and operations throughout the drawings.

[0016] One embodiment of the present invention provides a cap assembly for a cylindrical secondary battery that is coupled to an opening of a cylindrical can that accommodates an electrode assembly, the cap assembly comprising: a top cap located at the opening; and a vent positioned at the bottom of the top cap and surrounding the outer periphery of the top cap, wherein the vent comprises a honeycomb layer having a plurality of hexagonal column structures.

[0017] FIG. 1 is a vertical cross-sectional view of a cylindrical secondary battery including a cap assembly according to one embodiment of the present invention.

[0018] Specifically, the cylindrical secondary battery (100) may be in the form in which an electrode assembly (110) is accommodated inside a cylindrical can (120), and a positive electrode tab (111) is disposed on one side of the electrode assembly (110). The side of the positive electrode tab (111) opposite to the side where the electrode assembly (110) is disposed is an opening, and specifically, a cap assembly according to one embodiment of the present invention may be coupled to the opening of the cylindrical can (120).

[0019] A cap assembly according to one embodiment of the present invention may include a top cap (131) located at the opening and a vent (132) positioned at the bottom of the top cap (131) and surrounding the outer periphery of the top cap (131).

[0020] According to one embodiment of the present invention, the top cap (131) is formed with a central part protruding upward and can form a positive terminal.

[0021] The vent (132) may have a downwardly concave shape and may include a plurality of notches. When gas is generated inside the cylindrical battery (100) and the internal pressure rises, the vent (132) may protrude upward at a predetermined pressure and break to discharge the internal gas to the outside.

[0022] The electrode assembly housed within the above-described cylindrical can may be in the form of a coil with a separator placed between the anode and the cathode. Specifically, the laminated structure may be coiled in a 'jelly roll' shape, or it may be in the form of a stack of anode plates and cathode plates of a predetermined size with a separator in between.

[0023] FIG. 2 is a vertical cross-sectional view of a cap assembly for a cylindrical secondary battery according to one embodiment of the present invention.

[0024] Referring to FIG. 2, a cap assembly according to one embodiment of the present invention may include a top cap (131) located at the opening and a vent (132) positioned at the bottom of the top cap (131) and surrounding the outer periphery of the top cap (131).

[0025] The top cap (131) is formed with a central part protruding upward and may include a hole for discharging gas, and FIG. 2 is a cross-sectional view of the location where the hole is formed in the top cap (131).

[0026] Specifically, a cap assembly (130) according to one embodiment of the present invention may additionally include a clamping gasket (133), a lower gasket (134), and a current blocking member (135).

[0027] The clamping gasket (133) is positioned at the outer periphery of the vent (132) and can serve to seal the secondary battery while being in close contact with the opening of the cylindrical can. The cap assembly (130) of FIG. 2 is in a form before being coupled to the opening of the cylindrical secondary battery, and when coupled to the opening of the cylindrical secondary battery later, the clamping gasket (133) can be in close contact by wrapping around the outer periphery of the vent.

[0028] The current blocking member (135) may be located in the space between the vent (132) and the electrode assembly. The current blocking member (135) serves to block the current and relieve internal pressure when the cylindrical battery operates abnormally.

[0029] The lower gasket (134) may be located at the lower part of the vent (132) and at the outer periphery of the current blocking member (135), and may prevent the vent (132) and the current blocking member (135) from coming into contact at a part other than the center.

[0030] In addition, a cap assembly for a cylindrical secondary battery according to one embodiment of the present invention includes a vent comprising a honeycomb layer (202) comprising a plurality of hexagonal column structures to increase rigidity against physical deformation.

[0031] Specifically, the cap assembly (130) for a cylindrical secondary battery according to the present invention has a different structure of vent from a conventional cap assembly for a cylindrical secondary battery. Since the vent included in the conventional cap assembly is composed of a single layer that does not have a specific shape, when the cap assembly is deformed by being compressed from an external impact, the vent is also easily deformed, so there was a problem that a short circuit with the electrode easily occurred.

[0032] On the other hand, the vent (132) included in the cap assembly of the present invention includes a honeycomb layer (202) comprising a plurality of hexagonal column structures, so the rigidity of the vent against physical deformation is increased, and the vent is not easily deformed from external impact, thus having strong resistance to external impact without changing the material of the vent. Therefore, when using the cap assembly according to one embodiment of the present invention, a secondary battery with greatly improved stability can be provided.

[0033] In one embodiment of the present invention, the vent (132) includes a honeycomb layer (202) comprising a plurality of hexagonal column structures. The honeycomb layer (202) refers to a grid structure composed of a plurality of hexagonal column structures with a hollow center.

[0034] In one embodiment of the present invention, the vent (132) is formed with a structure that is easily broken as internal pressure increases, including a plurality of notches, and a honeycomb structure may not be formed in the notches.

[0035] In one embodiment of the present invention, the vent may further include a first support (201) disposed on the upper part of the honeycomb layer (202); and a second support (203) disposed on the lower part of the honeycomb layer (202).

[0036] FIG. 3 illustrates an embodiment of a vent included in the cap assembly.

[0037] Specifically, the vent may have a structure comprising a first support (201) disposed on the upper part of the honeycomb layer (202); and a second support (203) disposed on the lower part of the honeycomb layer. That is, the honeycomb layer (202) may be stacked on the second support (203), and the first support (201) may be stacked on the honeycomb layer (202) in that order.

[0038] Accordingly, the upper and lower portions of the vent (132) are composed of a first support (201) and a second support (203), but the space between the upper and lower portions of the vent is composed of a honeycomb layer (202) of a hexagonal column structure with a hollow center, thus including some empty space.

[0039] The increased rigidity due to the honeycomb layer (202) can prevent deformation from external impacts and improve battery stability. In addition, superior rigidity can be created compared to using a conventional vent without changing the material, and since the material is not changed, it can be applied without changing the existing process itself.

[0040] The method of laminating the first support, the honeycomb layer, and the second support of the above-mentioned vent is not particularly limited, and methods used in the industry may be appropriately adopted.

[0041] The first support, the honeycomb layer, and the second support may comprise the same material. The material is not particularly limited and may utilize any material having appropriate rigidity used in the industry. Specifically, it may comprise aluminum, and more specifically, it may comprise an aluminum alloy.

[0042] Figure 4 illustrates a part of the honeycomb layer included in the above vent.

[0043] Specifically, the honeycomb layer comprises a plurality of hexagonal prism structures with a hollow center, and the plurality of hexagonal prism structures are formed into a lattice structure by interlocking their sides. Although the thickness of the face of the hexagonal prism forming the honeycomb layer is not indicated in FIG. 4, it may have a certain thickness. Specifically, it may be 50 μm to 500 μm, more specifically 50 μm to 200 μm, and even more specifically 150 μm.

[0044] In one embodiment of the present invention, the length of one side (a) of the hexagonal column of the honeycomb layer may be longer than the height (b) of the honeycomb layer. When this is satisfied, the vent including the honeycomb layer may exhibit sufficient rigidity to withstand deformation caused by external impact.

[0045] In one embodiment of the present invention, the length (a) of one side of the hexagonal column of the honeycomb layer may be 0.4 mm to 1 mm, and preferably 0.6 mm to 0.8 mm.

[0046] In one embodiment of the present invention, the height (b) of the honeycomb layer may be 0.05 mm to 0.3 mm, and preferably 0.1 mm to 0.2 mm.

[0047] In one embodiment of the present invention, the thickness of the first support and the second support may each be independently 0.05 mm to 0.3 mm, and preferably 0.1 mm to 0.2 mm.

[0048] In one embodiment of the present invention, the ratio of the thickness of the first support to the thickness (height) of the honeycomb layer may be 1:2 to 2:1, and preferably 1:1.

[0049] In one embodiment of the present invention, the ratio of the thickness (height) of the honeycomb layer to the thickness of the second support may be 1:2 to 2:1, and preferably 1:1.

[0050] In one embodiment of the present invention, the ratio of the thickness of the first support to the thickness of the second support may be 1:2 to 2:1, and preferably 1:1.

[0051] In one embodiment of the present invention, the ratio of the thickness (height) of the honeycomb layer to the thickness of the second support may be 1:2 to 2:1, and preferably 1:1.

[0052] In one embodiment of the present invention, the ratio of the thickness of the first support: the thickness (height) of the honeycomb layer: the thickness of the second support may be 1:1:1.

[0053] If the above range is satisfied, the vent composed of the first support, the second support, and the honeycomb layer can exhibit sufficient rigidity to withstand deformation caused by external impact.

[0054] In one embodiment of the present invention, the thickness (c) of the vent may be 0.3 mm to 0.6 mm, and preferably 0.4 mm to 0.5 mm. The thickness of the vent may refer to the average thickness of the area excluding the notch.

[0055] By configuring the vent within the range described above, a cap assembly having excellent rigidity against external impact can be manufactured without changing the existing vent material.

[0056] One embodiment of the present invention provides a cylindrical secondary battery comprising: a cylindrical can that accommodates an electrode assembly in a wound form with a separator placed between an anode and a cathode; and the aforementioned cap assembly coupled to an opening of the cylindrical can.

[0057] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as described in the following claims. Explanation of the symbols

[0058] 100: Cylindrical secondary battery 110: Electrode assembly 111: Positive tab 120: Cylindrical can 130: Cap Assembly 131: Top Cap 132: Vent 133: Climbing gasket 134: Lower gasket 135: Current interrupting member 201: First support 202: Honeycomb layer 203: Second support

Claims

Claim 1 A cap assembly for a cylindrical secondary battery, comprising a cap assembly coupled to an opening of a cylindrical can that accommodates an electrode assembly, wherein the cap assembly comprises a top cap located at the opening; and a vent positioned at the bottom of the top cap and surrounding the outer periphery of the top cap, wherein the vent comprises a honeycomb layer having a plurality of hexagonal column structures. Claim 2 A cap assembly for a cylindrical secondary battery according to claim 1, wherein the vent further comprises a first support disposed on the upper part of the honeycomb layer; and a second support disposed on the lower part of the honeycomb layer. Claim 3 A cap assembly for a cylindrical secondary battery according to claim 1, wherein the length of one side of the hexagonal column of the honeycomb layer is longer than the height of the honeycomb layer. Claim 4 A cap assembly for a cylindrical secondary battery according to claim 2, wherein the thickness of the first support and the second support are each independently 0.05 mm to 0.3 mm. Claim 5 A cap assembly for a cylindrical secondary battery according to claim 1, wherein the height of the honeycomb layer is 0.05 mm to 0.3 mm. Claim 6 A cylindrical secondary battery cap assembly according to claim 1, wherein the length of one side of the hexagonal column of the honeycomb layer is 0.4 mm to 1 mm. Claim 7 A cap assembly for a cylindrical secondary battery according to claim 1, wherein the thickness of the vent is 0.3 mm to 0.6 mm. Claim 8 A cap assembly for a cylindrical secondary battery according to claim 2, wherein the first support, the honeycomb layer, and the second support comprise an aluminum alloy. Claim 9 A cap assembly for a cylindrical secondary battery according to claim 1, wherein the cap assembly comprises a clamping gasket located at the outer periphery of the vent and in close contact with the opening of the cylindrical can. Claim 10 A cap assembly for a cylindrical secondary battery according to claim 1, wherein the cap assembly further comprises a current blocking member located in the space between the vent and the electrode assembly and a lower gasket located at the outer periphery of the current blocking member. Claim 11 A cylindrical secondary battery comprising: a cylindrical can that accommodates an electrode assembly in a wound form with a separator placed between a positive electrode and a negative electrode; and a cap assembly according to any one of claims 1 to 10 that is coupled to an opening of the cylindrical can.

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