Cylindrical secondary battery

Abstract

Embodiments of the present application relate to a cylindrical secondary battery including a cylindrical can having one open end to form an opening, an electrode assembly received in the cylindrical can, and a cap assembly including a vent plate disposed at an outermost side in a direction away from the opening and having at least one notch, a lower cap disposed to be spaced apart from the vent plate in a direction of the opening and electrically connected to the electrode assembly, a support plate disposed between the vent plate and the lower cap to be coupled to the vent plate, and an insulating member interposed between the support plate and the lower cap to insulate the support plate and the lower cap from each other, wherein the vent plate is ruptured to be separated from the cap assembly when a gas inside the can is discharged toward the opening.

Description

Technical Field

[0001] Embodiments of the present invention relate to a cylindrical secondary battery that maximizes gas emission efficiency while maintaining operational stability. Background Technology

[0002] Typically, a cylindrical secondary battery includes a cylindrical electrode assembly, a cylindrical can containing the electrode assembly and electrolyte, and a cover assembly connected to the top opening of the can to seal the can and allow current generated from the electrode assembly to flow to an external device.

[0003] The cover assembly may include a vent plate that ruptures to release internal gas when the gas pressure inside the secondary battery rises above a set value. The vent plate is disposed inside the upper cover of the cover assembly. During the vent plate rupture, the upper cover is secured to the top of the can, and the vent plate is covered by the upper cover. Therefore, when residual gas is released after rupture, the gas outlet may be blocked or narrowed due to the ruptured vent plate.

[0004] The information disclosed in this background section is only intended to enhance the understanding of the background of the invention, and therefore may include information that does not constitute prior art. Summary of the Invention

[0005] Technical issues

[0006] The purpose of this invention is to provide a cylindrical secondary battery with a cover assembly that deforms during gas emission by means of components that fix the cover assembly during operation and rupture to maximize gas emission while maintaining operational stability.

[0007] Technical solution

[0008] A cylindrical secondary battery according to an embodiment of the present invention may include: a cylindrical can having an open end to form an opening; an electrode assembly housed in the cylindrical can; and a cover assembly including: a vent plate disposed on the outermost side in a direction away from the opening and having at least one notch; a lower cover disposed spaced apart from the vent plate in the direction of the opening and electrically connected to the electrode assembly; a support plate disposed between the vent plate and the lower cover to be coupled to the vent plate; and an insulating member inserted between the support plate and the lower cover to insulate the support plate and the lower cover from each other, wherein the vent plate breaks to separate from the cover assembly when gas inside the cylindrical can is discharged toward the opening.

[0009] The central portion of the lower cover can protrude toward the exhaust plate to form a connection part that attaches to the exhaust plate, and the connection part separates from the lower cover when the exhaust plate is in operation.

[0010] The connecting part may have a welded part that is welded to the exhaust plate, and the notch may be formed to be spaced apart from the welded part in the outward direction.

[0011] The support plate is formed as a circular plate and may have multiple slits and circular through holes. The multiple slits are spaced apart from the outer edge in the inward direction and are formed through the circumference. The circular through holes are formed through the through holes and are spaced apart from the multiple slits in the inward direction. Multiple second support portions with arc shapes may be formed between the multiple slits and through holes.

[0012] The exhaust plate can be formed as a circular plate and can include a curved portion formed by folding the outer edge of the exhaust plate, and the outer edge of the support plate can be a first support portion inserted into the curved portion.

[0013] The insulating component can be formed into a ring and can be disposed between multiple second supports and the lower cover.

[0014] The notch can be formed in the circumferential direction in the area between multiple gaps that connect the first support and multiple second supports respectively.

[0015] The recess of the exhaust plate is formed adjacent to the curved portion, and the recess of the support plate is formed spaced apart from the recess of the exhaust plate in the inward direction.

[0016] When the gas is released, the support plate can be flipped toward the exhaust plate, and the exhaust plate can be separated from the cover assembly.

[0017] When the gas is being discharged, the lower cover can be separated from the cover assembly when the exhaust plate is separated from the cover assembly.

[0018] The support plate and insulating member can be formed as a ring with a through hole formed in the center, and the insulating member can be arranged in the direction of the inner circumferential surface of the support plate so that the exhaust plate and the lower cover are insulated from each other.

[0019] The insulating component may have an outer edge that is attached to the inner edge of the support plate in a stacked state.

[0020] Beneficial effects

[0021] In embodiments of the invention, during operation of the cylindrical secondary battery, the upper cover with a recess formed therein remains fixed to the can, and when gas is released, the upper cover breaks and a portion of the lower cover breaks together. Furthermore, when gas is released, the lower cover also deforms and breaks due to the deformation of the support plate, causing the gas release channel to expand. Therefore, the gas release rate and gas release volume can be greatly increased, thereby maximizing the gas release effect. Attached Figure Description

[0022] Figure 1 This is a longitudinal sectional view showing a typical cylindrical secondary battery.

[0023] Figure 2It shows when the gas is according to Figure 1 A cross-sectional view of the state of the cover assembly when it is being discharged into the cover assembly.

[0024] Figure 3 This is a longitudinal sectional view showing a cylindrical secondary battery according to a first embodiment of the present invention.

[0025] Figure 4 It shows the basis Figure 3 A plan view of the support plate of the cover assembly.

[0026] Figure 5 It shows the basis Figure 3 A cross-sectional view of the exhaust plate in the cover assembly in its working state.

[0027] Figure 6 It is shown Figure 5 A cross-sectional view of the vent plate in the cover assembly in a fractured state.

[0028] Figure 7 It shows when the gas is according to Figure 6 A cross-sectional view of the state of the cover assembly when it is being discharged into the cover assembly.

[0029] Figure 8 It shows the basis Figure 7 A cross-sectional view of the cover assembly in its final state after gas venting.

[0030] Figure 9 This is a cross-sectional view of the cover assembly of a cylindrical secondary battery according to a second embodiment of the present invention.

[0031] Figure 10 This illustrates a secondary battery according to an embodiment of the present invention. Figure 9 A cross-sectional view of the vent plate in the cover assembly in a fractured state. Detailed Implementation

[0032] Examples of the invention are provided to explain it more fully to those skilled in the art, and the following examples can be modified in various other forms. However, the invention can be embodied in many different forms and should not be construed as limited to the examples (or exemplary) embodiments set forth herein. Rather, these exemplary embodiments are provided so that the invention will be thorough and complete, and will convey aspects and features of the invention to those skilled in the art.

[0033] Additionally, for the sake of brevity and clarity, the dimensions or thicknesses of various components are exaggerated in the accompanying drawings, and the same reference numerals consistently denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, it will be understood that when element A is referred to as being "connected to" element B, element A may be directly connected to element B, or there may be an intermediary element C between element A and element B, such that element A and element B are indirectly connected to each other.

[0034] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising or including” and / or variations thereof are used in this specification, it indicates the presence of the stated features, numbers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, and / or groups thereof.

[0035] It will be understood that although the terms first, second, etc., may be used herein to describe various components, elements, regions, layers, and / or portions, these components, elements, regions, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one component, element, region, layer, and / or portion from another component, element, region, layer, and / or portion. Thus, for example, without departing from the teachings of the invention, the first component, first element, first region, first layer, and / or first portion discussed below may be referred to as a second component, second element, second region, second layer, and / or second portion.

[0036] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” and “above” may be used herein to describe the relationship of one element or feature to other elements or features as shown in the accompanying drawings. It will be understood that, in addition to the orientation depicted in the drawings, the spatial relative terms are intended to cover different orientations of the device during use or operation. For example, if an element or feature in the drawings is flipped, an element described as “below” or “under” other elements or features would then be oriented “above” or “above” said other elements or features. Thus, the exemplary term “below” can encompass both above and below orientations.

[0037] In the following, a cylindrical secondary battery according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0038] Figure 1 This is a longitudinal sectional view showing a typical cylindrical secondary battery. Figure 2 It shows when the gas is according to Figure 1A cross-sectional view of the state of the cover assembly when it is being discharged into the cover assembly.

[0039] like Figure 1 and Figure 2 As shown, a typical cylindrical secondary battery A includes: a cylindrical can 10 having an opening formed at one end in the longitudinal direction; an electrode assembly 30 housed inside the can; and a cover assembly 50 inserted into the opening. The cover assembly 50 includes a safety vent 51, an upper cover 52 disposed above the safety vent 51, and a lower cover 53 disposed below the safety vent 51. The cover assembly 50 may further include an insulating member 54 and an insulating gasket 55. The insulating member 54 is inserted between the safety vent 51 and the lower cover 53 to prevent a portion of the safety vent 51 other than its center from contacting the lower cover 53. The insulating gasket 55 insulates the cover assembly 50 and the can 10 from each other. In the safety vent 51, a portion of the can 10 near its longitudinal central axis Y1 contacts the lower cover 53, and a portion supported by the insulating member 54 is spaced apart from the lower cover 53. A notch 51a is formed in the safety vent 51. On one open side of the can 10, the lower part of the lid assembly 50 is recessed in an annular shape to form a rolled edge 12, and the upper part of the lid assembly 50 is bent inward to form a crimped part 14.

[0040] When the pressure inside the secondary battery A rises above a certain pressure level, the safety vent 51 deforms and the notch 51a ruptures, allowing the gas inside the secondary battery A to be released. The gas passes through the ruptured safety vent 51 and is discharged to the outside of the secondary battery A through the through hole 52a formed in the top cover 52.

[0041] However, as Figure 2 As shown, even if the safety vent 51 ruptures, the safety vent 51 itself remains between the upper cover 52 and the lower cover 53, and the upper cover 52 also remains in its original position. Therefore, the safety vent 51 may block the passage for gas to be discharged. In this case, the gas inside the secondary battery A cannot be discharged quickly. To solve this problem, the present invention proposes a new cover assembly structure.

[0042] Figure 3 This is a longitudinal sectional view showing a cylindrical secondary battery according to a first embodiment of the present invention. Figure 4 It shows the basis Figure 3 A plan view of the support plate of the cover assembly.

[0043] like Figure 3 and Figure 4As shown, the cylindrical secondary battery B according to the first embodiment of the present invention may include a cylindrical can 100, an electrode assembly 300 inserted into the can 100, a cover assembly 500 inserted into one end of the can 100, and an insulating washer 700 inserted between the can 100 and the cover assembly 500. A center pin 380 may be attached to the electrode assembly 300.

[0044] The can 100 includes a circular bottom 110 and a side 130 extending upward from the bottom 110, with the upper part of the side 130 being open (hereinafter referred to as the opening). In the manufacturing process of the secondary battery B, the electrode assembly 300, together with the electrolyte, is inserted into the can 100 through the opening. The can 100 may be made of steel, steel alloy, nickel-plated steel, nickel-plated steel alloy, aluminum, aluminum alloy, or equivalents, but the material is not limited thereto.

[0045] The cap assembly 500 is inserted into the opening of the can 100 (which will be described later). A rolled edge 132 and a crimped portion 134 may be formed on the side 130 to prevent the inserted cap assembly 500 from escaping to the outside through the opening of the can 100.

[0046] A rolled edge 132 is formed below the cap assembly 500 and recessed towards the interior of the can 100. A crimping portion 134 is formed above the cap assembly 500 and shaped to bend towards the interior of the can 100. Because the rolled edge 132 and the crimping portion 134 grip the cap assembly 500 in the vertical direction, the cap assembly 500 can remain attached to the can 100. The electrode assembly 300 is disposed inside the can 100 below the cap assembly 500.

[0047] The electrode assembly 300 includes a negative electrode plate 310 coated with a negative electrode active material (e.g., graphite, carbon, etc.), a positive electrode plate 320 coated with a positive electrode active material (e.g., transition metal oxides (LiCoO2, LiNiO2, LiMn2O4, etc.)), and a separator 330 disposed between the negative electrode plate 310 and the positive electrode plate 320 to prevent short circuits and allow only lithium ion movement. The negative electrode plate 310, the positive electrode plate 320, and the separator 330 can be wound in a substantially cylindrical shape and housed inside the can 100.

[0048] The negative electrode plate 310 can be copper (Cu) foil or nickel (Ni) foil, the positive electrode plate 320 can be aluminum (Al) foil, and the diaphragm 330 can be polyethylene (PE) or polypropylene (PP), but these materials are not limited in this invention. A downwardly protruding negative electrode tab 340 extending a certain length can be welded to the negative electrode plate 310, and an upwardly protruding positive electrode tab 350 extending a certain length can be welded to the positive electrode plate 320, but the reverse is also possible. The negative electrode tab 340 can be made of copper or nickel, and the positive electrode tab 350 can be made of aluminum, but these materials are not limited in this invention. The negative electrode tab 340 can be welded to the bottom 110 of the can 100, in which case the can 100 can operate as a negative electrode. Conversely, the positive electrode tab 350 can be welded to the bottom 110 of the can 100, in which case the can 100 can operate as a positive electrode.

[0049] Additionally, the first insulating plate 360 ​​and the second insulating plate 370 can be positioned above and below the electrode assembly 300, respectively. The first insulating plate 360 ​​prevents the positive electrode plate 320 from making electrical contact with the bottom 110 of the canister 100, and the second insulating plate 370 prevents the negative electrode plate 310 from making electrical contact with the cover assembly 500.

[0050] To allow gas to move upwards in the event of a large amount of gas generated due to an anomaly in the secondary battery, the first insulating plate 360 ​​includes a first hole 362 communicating with the center pin 380 and a second hole 364 through which the negative electrode tab 340 can pass. The negative electrode tab 340 can be soldered to the bottom 110 through the second hole 364.

[0051] The second insulating plate 370 includes a first hole 372 and a second hole 374. When a large amount of gas is generated due to an anomaly in the secondary battery, the gas can move to the cover assembly 500 through the first hole 372. The second hole 374 is formed through the second insulating plate 370 to allow the positive electrode tab 350 to penetrate. The positive electrode tab 350 can be welded to the lower cover 550, which will be described later, through the second hole 374. A plurality of second holes 374 can be formed as inlets for electrolyte injection into the electrode assembly 300 during the electrolyte injection process.

[0052] The center pin 380 is formed as a hollow circular tube and can be attached to the center of the electrode assembly 300. The center pin 380 can be made of steel, steel alloy, nickel-plated steel, nickel-plated steel alloy, aluminum, aluminum alloy, or polybutylene terephthalate, but the material is not limited thereto. The center pin 380 is used to suppress deformation of the electrode assembly 300 during the charging and discharging of the secondary battery and serves as a channel for gases generated inside the secondary battery. In some cases, the center pin 380 can be omitted.

[0053] On the other hand, such as Figure 3As shown, the cover assembly 500 may include an exhaust plate 510 exposed to the outside of the can 100, a lower cover 550 disposed below the exhaust plate 510, a support plate 530 disposed between the exhaust plate 510 and the lower cover 550, and an insulating member 570 disposed between the support plate 530 and the lower cover 550. Figure 3 In this context, based on an imaginary central axis Y2 along the longitudinal direction of tank 100, the direction toward the central axis Y2 is defined as the inward direction, and the direction away from the central axis Y2 is defined as the outward direction. Furthermore, based on... Figure 3 The upper side is defined as the upper direction, and the lower side is defined as the lower direction.

[0054] like Figure 3 As shown, the exhaust plate 510 is located at the uppermost part of the cover assembly 500 (based on what will be described later). Figure 3 and Figure 5 (At the very top). More specifically, the vent plate 510 is located at the outermost point of the cover assembly 500, furthest from the opening of the can 100. The vent plate 510 serves as a safety vent and can replace the function of the top cover in a cover assembly 500 where the top cover is omitted. The vent plate 510 can be made of the same or similar material as the bottom cover 550, which will be described later. In addition, for the smooth breaking operation of the vent plate 510, the material of the vent plate 510 can have less rigidity than the material of the bottom cover 550.

[0055] The exhaust plate 510 is formed as a substantially circular plate, and its outer edge is folded toward the opening of the canister 100 to form a bend 512. The bend 512 is formed around the outer edge of the support plate 530, which will be described later. (See reference...) Figure 3 The curved portion 512 is shaped to bend downwards.

[0056] Furthermore, the exhaust plate 510 has a notch 510a formed along the circumferential direction between the curved portion 512 and the imaginary central axis Y2. The notch 510a can be formed in a ring shape along the circumferential direction, or multiple fan-shaped shapes can be arranged at regular intervals. The notch 510a is the part that breaks when gas is discharged, and can be formed on the plate surface of the exhaust plate 510 facing the opening of the canister 100. Thus, the exhaust plate 510 of the present invention does not have a structure corresponding to the through hole 52a formed in the conventional top cover 52.

[0057] In addition, based on Figure 3 The exhaust plate 510 may have a step, such that the curved portion 512 is positioned below other portions of the plate surface. Generally based on the notch 510a, the inward plate surface may be formed higher than the edge plate surface on the side of the curved portion 512. That is, based on... Figure 3 The exhaust plate 510 has a shape that protrudes in the upward direction.

[0058] like Figure 3 and Figure 4 As shown, the support plate 530 is formed by processing a substantially circular plate material. In the support plate 530, a plurality of slits 534 penetrate inward in a direction toward the central axis Y2, spaced apart from the outer edge of the circular plate shape. The slits 534 have an arcuate shape, and the plurality of slits 534 are arranged to be spaced apart at regular intervals. A substantially circular through-hole 538 penetrates inward in a portion spaced apart from the slits 534.

[0059] The outer edge of the support plate 530 has a predetermined width (width in the radial direction) and is defined as a first support portion 532. Part or all of the first support portion 532 is covered by the curved portion 512 of the exhaust plate 510. The area between the slit 534 and the through hole 538 is defined as a second support portion 536. Since the slit 534 has an arcuate shape and the through hole 538 is circular, the second support portion 536 has multiple arcuate shapes. The first support portion 532 and the second support portion 536 connect to the area between the slits 534. A notch 530a is formed between the slits 534 that connect the first support portion 532 and the second support portion 536, respectively. The notch 530a is formed more inwardly than the notch 510a of the exhaust plate 510. When gas is discharged, the second support portion 536 deforms and flips in the upward direction based on the notch 530a, thereby rapidly discharging gas. However, the support plate 530 can remain in a deformed state without separating from the cover assembly. The support plate 530 may be made of the same or similar material as the insulating member 570. Optionally, the lower cover 550 may be made of the same or similar material.

[0060] Furthermore, the first support portion 532 and the second support portion 536 have steps relative to each other. Based on Figure 3 (and will be described later) Figure 5 The upper surface of the second support portion 536 is positioned higher than the upper surface of the first support portion 532. That is to say, based on... Figure 3 The support plate 530 protrudes upwards. This structure corresponds to the stepped structure of the exhaust plate 510.

[0061] Therefore, based on Figure 3 The first support portion 532 is positioned such that a portion of its lower surface facing the opening of the can 100 is wrapped by the curved portion 512, and most of its upper surface is in contact with the lower surface of the exhaust plate 510. The second support portion 536 is positioned such that its entire upper surface is in contact with the lower surface of the exhaust plate 510. The second support portion 536 is positioned inwardly from the recess 510a of the exhaust plate 510. In this state, the lower cover 550 is configured such that the insulating member 570 is placed between the second support portion 536 and the lower cover 550.

[0062] like Figure 3As shown, the lower cover 550 is formed as a substantially circular plate and is disposed below the exhaust plate 510. In the lower cover 550, the central portion of the disc protrudes upward in a substantially cylindrical shape and is in close contact with the lower surface of the exhaust plate 510. Conversely, the lower cover 550 has an edge that curves downward from the central portion. The portion of the lower cover 550 that is in close contact with the exhaust plate 510 is defined as the connecting portion 552. The edge of the circular plate of the lower cover 550 is disposed on the lower surface of the second support portion 536 of the support plate 530, and the insulating member 570 is located between the edge of the circular plate of the lower cover 550 and the lower surface of the second support portion 536. In this state, the connecting portion 552 and the exhaust plate 510 are welded and fixed. Only the weld portion 554 to be welded is connected to the exhaust plate 510, and the other portions do not contact the exhaust plate 510. A notch 550a may be formed on the connecting portion 552 in a radial direction and spaced apart from the weld portion 554 in an outward direction. When the gas is released, a portion of the notch 550a on the connector 552 breaks.

[0063] The insulating member 570 allows the support plate 530 and the lower cover 550 to remain separated and serves to insulate the support plate 530 and the lower cover 550 from each other. Therefore, when viewed from above, the insulating member 570 can be formed in the shape of an annulus with a predetermined width. For example, the insulating member 570 may be made of polyethylene (PE), polypropylene (PP), ethylene propylene diene monomer (M-type) rubber (EPDM rubber), or equivalents thereof, but is not limited thereto. The insulating member 570 can be welded to the support plate 530 and the lower cover 550 by ultrasonic welding or laser welding.

[0064] As described above, when the exhaust plate 510, support plate 530, lower cover 550, and insulating member 570 are combined to form the cover assembly 500, the curved portion 512 of the exhaust plate 510 covers the first support portion 532 of the support plate 530. Therefore, the lower surface of the second support portion 536 of the support plate 530 and the exhaust plate 510 are in contact with each other. Here, the support plate 530 and the lower cover 550 are combined, and the insulating member 570 is located between the support plate 530 and the lower cover 550. Furthermore, the connecting portion 552 of the lower cover 550 is welded to the lower surface of the exhaust plate 510. This state is defined as the assembled state of the cover assembly 500.

[0065] In the cylindrical secondary battery having the above-described structure, the states of various components of the cover assembly according to the gas emission process will now be described (refer to...). Figure 3 (Describe the components not shown in the accompanying drawings).

[0066] Figure 5 It shows the basis Figure 3 A cross-sectional view of the exhaust plate in the cover assembly in its working state. Figure 6 It is shown Figure 5A cross-sectional view of the vent plate in the cover assembly in a fractured state. Figure 7 It shows when the gas is according to Figure 6 A cross-sectional view of the state of the cover assembly when it is being discharged into the cover assembly. Figure 8 It shows the basis Figure 7 A cross-sectional view of the cover assembly in its final state after gas venting.

[0067] like Figure 5 As shown, the vent plate 510 operates when abnormal pressure is generated inside the cylindrical secondary battery B due to overcharging or other reasons. When the vent plate 510 operates, it bulges upward and deforms due to the gas trapped inside the secondary battery B, thus separating the connecting portion 552 of the lower cover 550 based on the notch 550a.

[0068] When the internal gas pressure gradually increases and becomes greater than the predetermined rupture pressure, the notch 510a of the exhaust plate 510 ruptures, and a portion of the exhaust plate 510 moves upward (e.g., Figure 6 (As shown in the diagram) Even if the notch breaks, the bent portion remains connected to the support plate.

[0069] When gas is momentarily released due to the gas discharge passage opening through the rupture of the exhaust plate 510, the second support portion 536 of the support plate 530 can be flipped upward based on the notch 530a by strong gas pressure (e.g., Figure 7 (As shown in the diagram). Since notch 530a is a relatively weak part compared to the other parts, deformation occurs in this part. Figure 7 As shown, since the second support portion 536 pushes the exhaust plate 510 upward while simultaneously pushing it upward, the exhaust plate 510 completely breaks and can be separated from the cover assembly 500. The notch 510a of the exhaust plate 510, rather than the notch 530a of the support plate 530, is preferably provided outward to allow the exhaust plate 510 to easily separate from the second support portion 536. That is, the aforementioned reason is that when the notch 530a moves away from the bend 512, the notch 530a of the support plate 530 is easily flipped and deformed in the upward direction. When the exhaust plate 510 is separated, the inward portion of the exhaust plate 510 based on the notch 510a is removed, and the outward portion of the exhaust plate 510 based on the notch 510a and the bend 512 remain connected to the support plate 530. Simultaneously, the lower cover 550 is also pushed upward by strong gas pressure, and the insulating member 570 is also damaged and may separate from the support plate 530 (the insulating member is melted or damaged by the strong gas pressure and high temperature). When the exhaust plate 510 and the lower cover 550 are separated from the cover assembly 500, the cross-sectional area through which the gas can be discharged increases, allowing the gas to be discharged more quickly.

[0070] When gas is discharged, the exhaust plate 510 and the lower cover 550 separate from the cover assembly 500 and are removed, while the support plate 530 remains in a deformed state. Therefore, the cover assembly 500 ultimately has the following characteristics: Figure 8 The shape shown.

[0071] In the above embodiments, it has been described that the support plate 530 consists of a first support portion 532 and a second support portion 536, and that when gas is discharged, the second support portion 536 deforms in the upward direction to facilitate the breaking and opening of the exhaust plate 510. Hereinafter, an embodiment in which the support plate 530 has an annular shape will be described (detailed descriptions of the same construction as in the above embodiments will be omitted).

[0072] Figure 9 This is a cross-sectional view of the cover assembly of a cylindrical secondary battery according to a second embodiment of the present invention. Figure 10 This illustrates a secondary battery according to an embodiment of the present invention. Figure 9 A cross-sectional view of the fractured state of the exhaust plate in the cover assembly.

[0073] like Figure 9 As shown, the support plate 530' is an annular plate material with a through hole 536' formed therein. The support plate 530' is mounted such that the curved portion 512 of the exhaust plate 510 surrounds the outer edge of the support plate 530'. The portion covered by the curved portion 512 is referred to as the first support portion 532'. The upper surface of the support plate 530' contacts the lower surface of the exhaust plate 510, and the lower surface contacts the upper surface of the outer edge of the insulating member 570'. This portion is referred to as the second support portion 534'. The upper surface of the second support portion 534' can be shaped to correspond to the shape of the exhaust plate 510 and be higher than the upper surface of the first support portion 532'.

[0074] Insulating member 570' is based on Figure 9 The predetermined width (length in the left-right direction (the direction perpendicular to the central axis Y2) and based on Figure 9The insulating member 570' is a generally annular insulator with a thickness (length in the vertical direction (direction of the central axis Y2)). The insulating member 570' is positioned on the inner circumferential surface of the support plate 530'. That is, the insulating member 570' is positioned further inward than the support plate 530'. The insulating member 570' includes a first insulating portion 572' and a second insulating portion 574'. The first insulating portion 572' has an upper surface that contacts the lower surface of the second support portion 534', which is the inner edge of the support plate 530'. The second insulating portion 574' extends inward from the first insulating portion 572' and has an upper surface that contacts the lower surface of the exhaust plate 510 and a lower surface that contacts the upper edge surface of the lower cover 550. The first insulating portion 572' is attached to the second support portion 534' in a stacked state. The second insulating portion 574' is formed at a position corresponding to the position of the second support portion 536 of the support plate 530 in the first embodiment described above. The support plate 530' is insulated and supported by the first insulating portion 572', and the exhaust plate 510 is insulated and supported by the second insulating portion 574'. Therefore, the insulating member 570' insulates the exhaust plate 510 and the lower cover 550 from each other, and also insulates the support plate 530' and the lower cover 550 from each other. The first insulating portion 572' is joined to the support plate 530' by welding or the like, and the second insulating portion 574' is joined to the exhaust plate 510 and the lower cover 550. Since the distance between the lower cover 550 and the exhaust plate 510 is greater than the distance between the lower cover 550 and the support plate 530', the thickness of the second insulating portion 574' is greater than the thickness of the first insulating portion 572'.

[0075] like Figure 10 As shown, when the exhaust plate 510 breaks and deforms upwards during gas emission, the insulating member 570' attached to the exhaust plate 510 is pulled up, and the lower cover 550 moves together. As the lower cover 550 moves, the working breakage dispersion of the exhaust plate 510 increases, and the remaining portion of the exhaust plate 510 is prone to breakage, thus allowing for rapid gas emission. The final remaining portion after gas emission can be a support plate 530', as in the first embodiment.

[0076] As described above, when the gas inside the cylindrical secondary battery is released, the support plate or lower cover can deform due to the pressure of the gas in the gas release direction, and the working dispersion of the vent plate increases. Therefore, after rupture, the vent plate can easily separate from the cover assembly, thus opening the gas release channel without being blocked by the remaining parts, allowing the gas to be released quickly. Furthermore, since the upper cover is omitted and the vent plate performs the functions of both a safety vent and an upper cover, it has the advantage of allowing gas to be released quickly through the rupture and separation of the vent plate.

[0077] While the foregoing embodiments have been provided for implementing the secondary battery according to the invention, it should be understood that the embodiments described herein should be considered in a descriptive sense only and not for limiting purposes, and various changes in form and detail may be made without departing from the spirit and scope of the invention as defined by the claims.

[0078] Industrial applicability

[0079] This invention can be widely applied to the field of secondary batteries and various devices or vehicles in which secondary batteries are installed.

Claims

1. A cylindrical secondary battery, the cylindrical secondary battery comprising: A cylindrical container with an open end to form an opening; The electrode assembly is housed in the cylindrical container; as well as A cover assembly comprising: an exhaust plate disposed on the outermost side in a direction away from the opening and having at least one notch; a lower cover disposed spaced apart from the exhaust plate in the direction of the opening and electrically connected to the electrode assembly; a support plate disposed between the exhaust plate and the lower cover for attachment to the exhaust plate; and an insulating member inserted between the support plate and the lower cover to insulate the support plate and the lower cover from each other. When the gas inside the cylindrical can is discharged toward the opening, the exhaust plate breaks to separate from the cover assembly. The support plate has multiple slits and notches, the slits being spaced inward from the outer edge of the support plate and extending circumferentially. The notch of the support plate is formed in the circumferential direction in the region between the plurality of gaps, and is spaced apart from the notch of the exhaust plate and farther away from the outer edge than the notch of the exhaust plate.

2. The cylindrical secondary battery according to claim 1, wherein, The central portion of the lower cover protrudes toward the exhaust plate to form a connection portion that attaches to the exhaust plate, and the connection portion separates from the lower cover when the exhaust plate is in operation.

3. The cylindrical secondary battery according to claim 2, wherein, The connecting portion has a weld portion that is welded to the exhaust plate, and the notch of the exhaust plate is formed to be spaced apart from the weld portion in the outward direction.

4. The cylindrical secondary battery according to claim 3, wherein, The support plate is formed as a circular plate and also has a circular through hole through which a plurality of second support portions are formed to be spaced apart from the plurality of gaps in an inward direction and have an arc shape and are spaced apart from each other between the plurality of gaps and the through hole.

5. The cylindrical secondary battery according to claim 4, wherein, The exhaust plate is shaped as a circular plate and includes a curved portion formed by folding the outer edge of the exhaust plate, and the outer edge of the support plate is a first support portion inserted into the curved portion.

6. The cylindrical secondary battery according to claim 5, wherein, The insulating member is formed into a ring and is disposed between the plurality of second supports and the lower cover.

7. The cylindrical secondary battery according to claim 5, wherein, The regions between the plurality of gaps respectively connect the first support portion and the plurality of second support portions.

8. The cylindrical secondary battery according to claim 7, wherein, The notch of the exhaust plate is formed adjacent to the curved portion.

9. The cylindrical secondary battery according to claim 8, wherein, When the gas is released, the support plate flips toward the exhaust plate, and the exhaust plate separates from the cover assembly.

10. The cylindrical secondary battery according to claim 3, wherein, When the gas is discharged, the lower cover separates from the cover assembly when the exhaust plate separates from the cover assembly.

11. A cylindrical secondary battery, the cylindrical secondary battery comprising: A cylindrical container with an open end to form an opening; The electrode assembly is housed in the cylindrical container; as well as A cover assembly comprising: an exhaust plate disposed on the outermost side in a direction away from the opening and having at least one notch; a lower cover disposed spaced apart from the exhaust plate in the direction of the opening and electrically connected to the electrode assembly; a support plate disposed between the exhaust plate and the lower cover for attachment to the exhaust plate; and an insulating member inserted between the support plate and the lower cover to insulate the support plate and the lower cover from each other. When the gas inside the cylindrical can is discharged toward the opening, the exhaust plate breaks to separate from the cover assembly. The support plate and the insulating member are formed as rings with a centrally located through hole, and the insulating member is disposed in the direction of the inner circumferential surface of the support plate so that the exhaust plate and the lower cover are insulated from each other. The insulating component is attached to the exhaust plate.

12. The cylindrical secondary battery according to claim 11, wherein, The insulating member has an outer edge that is attached to the inner edge of the support plate in a stacked state.

13. The cylindrical secondary battery according to claim 11, wherein, The central portion of the lower cover protrudes toward the exhaust plate to form a connection portion that attaches to the exhaust plate, and the connection portion separates from the lower cover when the exhaust plate is in operation.

14. The cylindrical secondary battery according to claim 13, wherein, The connecting portion has a weld portion that is welded to the exhaust plate, and the notch is formed to be spaced apart from the weld portion in the outward direction.

15. The cylindrical secondary battery according to claim 14, wherein, When the gas is discharged, the lower cover separates from the cover assembly when the exhaust plate separates from the cover assembly.

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