Cap assembly and secondary battery including the same

Abstract

A secondary battery cover assembly or the like having an improved structure such that emission of heated active material is blocked or reduced in the event of, for example, gas release. A cover assembly according to one aspect of the present invention is a secondary battery cover assembly coupled to an open end of a battery can, the cover assembly including: a top cover arranged to protrude from a top portion to form a cathode terminal; a safety vent formed below the top cover so as to have a varying shape during an increase in internal pressure of the battery can; a gasket for surrounding edges of the top cover and the safety vent; and a shielding member interposed between the top cover and the safety vent, the shielding member having an edge surrounded by the gasket and having at least a portion formed as a mesh.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2020-0140614, filed on October 27, 2020, in the Republic of Korea, the disclosure of which is incorporated herein by reference.

[0002] This disclosure relates to a secondary battery and a cover assembly for the secondary battery, and more particularly to a secondary battery having enhanced safety in the event of fire or explosion and a cover assembly for the secondary battery. Background Technology

[0003] Recently, with the widespread use of portable devices such as smartphones and laptops, transportation devices such as electric vehicles, electric kickboards and electric two-wheelers, and devices such as energy storage systems (ESS), there has been increasing attention on secondary batteries as a core component for supplying electricity.

[0004] Specifically, because rechargeable batteries can be reused for extended periods through charging and discharging, they have become widely used in various fields in recent years. Rechargeable batteries can include several types. Among them, lithium-ion batteries have a larger capacity compared to nickel-cadmium or nickel-metal hydride batteries, and are particularly favored due to their high energy density per unit weight; therefore, lithium-ion batteries are being used more and more extensively.

[0005] Lithium-ion secondary batteries typically use lithium oxide and carbonaceous materials as the positive and negative electrode active materials, respectively. A lithium-ion secondary battery includes an electrode assembly and an external material. In the electrode assembly, positive and negative electrode plates, coated with the positive and negative active materials respectively, are arranged with a separator inserted between them. The external material seals and receives the electrode assembly and the electrolyte.

[0006] Furthermore, based on the shape of the battery case, lithium secondary batteries can be classified into can-type secondary batteries and pouch-type batteries. In can-type secondary batteries, the electrode assembly is included in a battery can made of metal material, while in pouch-type batteries, the electrode assembly is included in a pouch made of aluminum laminate. Additionally, based on the shape of the metal can, can-type secondary batteries can be further classified into cylindrical batteries and rectangular batteries. The external material of rectangular or cylindrical secondary batteries includes a battery can and a cover assembly, which is sealed to the open end of the battery can.

[0007] Figure 1 This is a cross-sectional view of the cover assembly 10 of a conventional cylindrical secondary battery.

[0008] Reference Figure 1A cylindrical secondary battery typically includes: a cylindrical battery canister 20; a wound electrode assembly 30 received in the battery canister 20; a cover assembly 10 attached to the upper portion of the battery canister 20; a rolled edge portion 40 disposed at the front end of the battery canister 20 for mounting the cover assembly 10; and a crimping portion 50 for sealing the battery.

[0009] The electrode assembly 30 is wound into a core shape with the separator positioned between the positive and negative electrodes. The positive lead 31 is attached to the positive electrode and connected to the cover assembly 10, and the negative lead (not shown) is attached to the negative electrode and connected to the lower end of the battery canister 20.

[0010] The cover assembly 10 includes: a top cover 11 forming the positive terminal; a safety vent 12 for interrupting current and / or for venting gas when pressure increases in the battery; an insulating member 13 for electrically separating the safety vent 12 from the current interruption member 14, except in a specific portion; and the current interruption member 14 connected to the positive lead 31 connected to the positive terminal. The top cover 11, safety vent 12, insulating member 13, and current interruption member 14 are laminated in the above order. Additionally, the cover assembly 10 is mounted to the rolled edge portion 40 of the battery canister 20 in the state of being mounted to the gasket 15. Therefore, under normal operating conditions, the positive terminal of the electrode assembly 30 is electrically connected to the top cover 11 via the positive lead 31, the current interruption member 14, and the safety vent 12.

[0011] In this cover assembly, when the electrode assembly 30 catches fire, the pressure inside the battery canister 20 increases. This increased pressure causes the safety vent 12 to deform, allowing gases inside the battery canister 20 to escape to the outside. However, during this gas venting process, the active material of the electrode assembly 30 can be released to the outside of the battery canister 20 while heated. This high-temperature active material released in this way can adhere to other components around the secondary battery, such as other secondary batteries, as sediment, thereby heating that secondary battery.

[0012] Specifically, recently, instead of using a single secondary battery, it is common to use multiple secondary batteries, often housed within a single battery module or battery pack. For example, in the case of electric vehicles, a battery module or battery pack may include dozens or hundreds of secondary batteries. In this case, if a fire occurs in one of the secondary batteries, releasing the heated active material to the outside, it can cause a chain reaction of combustion by heating other secondary batteries around the burning battery. Furthermore, this chain reaction can not only damage the battery module or battery pack but also lead to significant problems, such as fires in the battery-containing device or structure, and personal injury. Summary of the Invention

[0013] Technical issues

[0014] This disclosure is designed to address the problems of the related art, and therefore aims to provide a cover assembly with an improved structure to block or reduce the emission of heated active material in the event of, for example, gas release, fire or explosion, and to provide a secondary battery using the cover assembly.

[0015] These and other objects and advantages of this disclosure may be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means and combinations thereof shown in the appended claims.

[0016] Technical solutions

[0017] In one aspect of this disclosure, a cover assembly for a secondary battery is provided, the cover assembly being coupled to an open end of a battery canister, the cover assembly comprising: a top cover disposed in a projecting manner on an uppermost portion of the cover assembly to form a positive terminal; a safety vent disposed below the top cover to deform in shape upon increased internal pressure in the battery canister; a gasket configured to surround an edge of the top cover and an edge of the safety vent; and a shielding member disposed between the top cover and the safety vent and having an edge surrounded by the gasket, the shielding member being at least partially configured in a mesh form.

[0018] Here, the cover assembly may also include a current interruption member having an upper portion and a lower portion, the upper portion being connected to the lower end of the safety vent and the lower portion being connected to the electrode assembly, and the current interruption member being configured to interrupt the electrical connection between the electrode assembly and the top cover when the safety vent is deformed.

[0019] Furthermore, the shielding member can be formed in a dome shape, such that at least the central portion of the shielding member protrudes upward.

[0020] In addition, the shielding member may include a protrusion formed to protrude upwards or downwards.

[0021] In addition, the shielding components may include multiple unit shielding components stacked on top of each other in the vertical direction.

[0022] Furthermore, the plurality of unit shields can be configured to have different mesh patterns from each other.

[0023] Furthermore, the upper shield among the plurality of unit shields may be formed in a dome shape such that at least the central portion protrudes upward, and the lower shield among the plurality of unit shields may be formed in a dome shape such that at least the central portion protrudes downward.

[0024] Furthermore, the lower shield can be configured such that the convex shape of the lower shield changes from the downward direction to the upward direction due to the deformation of the safety vent.

[0025] Furthermore, the lower shield can be configured such that when the convex shape is reversed, at least some of the holes formed in the lower shield are located in a different position in the horizontal direction than the holes formed in the upper shield.

[0026] In another aspect of this disclosure, a secondary battery including a cover assembly for a secondary battery according to this disclosure is also provided.

[0027] In another aspect of this disclosure, a battery pack comprising at least one secondary battery according to this disclosure is also provided.

[0028] Beneficial effects

[0029] According to this disclosure, the safety of secondary batteries can be improved.

[0030] Specifically, according to embodiments of this disclosure, when situations such as internal gas release caused by increased internal pressure of the secondary battery, or fire or explosion caused by thermal runaway occur, the emission of internal active materials to the outside of the battery can be blocked or reduced.

[0031] Specifically, in the event of a fire or explosion, the internal active materials can be at extremely high temperatures. Therefore, if the internal active materials are released to the outside, other secondary batteries could be heated, causing a chain reaction of fires or explosions within the battery module or battery pack. However, according to embodiments of this disclosure, even if a fire or explosion occurs in one or more secondary batteries, the release of the high-temperature internal active materials to the outside can be prevented, thereby preventing a chain reaction of fires or explosions. Attached Figure Description

[0032] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure should not be considered limited to the drawings.

[0033] Figure 1 This is a cross-sectional view showing the cover assembly of a conventional cylindrical secondary battery.

[0034] Figure 2 This is an exploded perspective view schematically showing a cover assembly included in a secondary battery according to an embodiment of the present disclosure.

[0035] Figure 3 This is a schematic cross-sectional view of the cover assembly of a secondary battery according to an embodiment of the present disclosure.

[0036] Figure 4This is a schematic top view of a shielding member included in a cover assembly according to an embodiment of the present disclosure.

[0037] Figure 5 This is a perspective view schematically showing a shielding member included in a cover assembly according to an embodiment of the present disclosure.

[0038] Figure 6 It is along Figure 5 The cross-sectional view taken by line B-B'.

[0039] Figure 7 It is a cross-sectional view schematically showing the state of deformation of the safety vent relative to the cover assembly according to an embodiment of the present disclosure.

[0040] Figure 8 This is a schematic cross-sectional view of some components of a shielding member according to another embodiment of the present disclosure.

[0041] Figure 9 This is a schematic cross-sectional view of a cover assembly for a secondary battery according to another embodiment of the present disclosure.

[0042] Figure 10 It is shown Figure 9 A magnified view of part of C2.

[0043] Figure 11 and Figure 12 This is a schematic top view of a shielding member according to another embodiment of the present disclosure.

[0044] Figure 13 This is a schematic cross-sectional view of a cover assembly according to yet another embodiment of the present disclosure. Detailed Implementation

[0045] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Before the description, it should be understood that the terminology used in the specification and appended claims should not be considered as limited to its general or dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present disclosure, based on the principle that the inventor is allowed to appropriately define the terminology for best description.

[0046] Therefore, the description presented herein is merely a preferred example for illustrative purposes and is not intended to limit the scope of this disclosure. It should be understood that other equivalent substitutions and modifications may be made to this disclosure without departing from its scope.

[0047] Figure 2 This is an exploded perspective view schematically illustrating a cover assembly 100 included in a secondary battery according to an embodiment of the present disclosure. Furthermore, Figure 3This is a schematic cross-sectional view of the cover assembly 100 of a secondary battery according to an embodiment of the present disclosure.

[0048] Reference Figure 2 and Figure 3 The secondary battery according to this disclosure includes an electrode assembly 300, a battery canister 200, and a cover assembly 100.

[0049] The electrode assembly 300 includes a positive electrode plate and a negative electrode plate and is received in the battery canister 200, with a separator between the positive and negative electrode plates. The electrode assembly 300 can be wound and configured as a core, and in this case, it is also referred to as a wound assembly. The electrode plates of the electrode assembly 300 can be configured such that the current collector is coated with an active material slurry, which is formed by mixing active material particles, auxiliary conductors, binders, plasticizers, etc., and a solvent is added to the slurry. Uncoated portions may exist at the beginning and end of the current collector along the winding direction of the electrode plates, and electrode leads corresponding to each electrode plate can be attached to the uncoated portions. Typically, the positive electrode lead 310 can be attached to the upper end of the electrode assembly 300 and electrically connected to the cover assembly 100, and the negative electrode lead (not shown) can be attached to the lower end of the electrode assembly 300 and connected to the bottom of the battery canister 200.

[0050] Meanwhile, although not shown in the accompanying drawings, an upper insulating plate may be provided at the upper end of the electrode assembly 300. This upper insulating plate can serve to insulate the electrode assembly 300 from the cover assembly 100.

[0051] The battery canister 200 is made of a lightweight, conductive metallic material, such as aluminum, stainless steel, or an alloy of aluminum and stainless steel, and may have a cylindrical or angled structure, wherein it has an opening at the upper end and a closed bottom opposite the opening. The electrode assembly 300 may be housed together with the electrolyte within the internal space of the battery canister 200.

[0052] Specifically, the secondary battery according to this disclosure can be a cylindrical battery, wherein the battery can 200 is formed in a cylindrical shape. However, the battery can 200 can be formed in various shapes other than cylindrical, such as prismatic.

[0053] According to this disclosure, a rolled edge portion can be formed on the battery can 200, such as... Figure 2 and Figure 3 As shown. However, this disclosure is not necessarily limited to the form of the battery can 200, and this disclosure can also be applied to battery cans 200 where the rolled edge portion is not formed thereon.

[0054] The cover assembly 100 for a secondary battery according to this disclosure is a component of the secondary battery. The cover assembly 100 is connected to the upper end, i.e., the open end, of the battery can 200 and, when connected to the open end of the battery can 200, can seal the internal space of the battery can 200. The cover assembly 100 can be formed into various shapes depending on the shape of the battery can 200, such as a circular shape or a prismatic shape.

[0055] The cover assembly 100 for a secondary battery according to this disclosure includes a top cover 110, a safety vent 120, a gasket 130, and a shielding member 140.

[0056] The top cover 110 may be disposed on the uppermost portion of the cover assembly 100 in an upwardly projecting manner to form a positive terminal. Therefore, the top cover 110 may be configured to be electrically connected to an external device, such as a load or charging device. Alternatively, the top cover 110 may be configured to be electrically connected to another secondary battery. Specifically, multiple secondary batteries may be electrically connected to each other in series and / or parallel to form a battery module or battery pack. In this case, the top cover 110 may contact the top cover 110 of another secondary battery or the battery canister 200, or contact a connecting member such as a busbar.

[0057] Gas vents can be formed in the top cover 110, such as in Figure 2 The gas is indicated by V, allowing gas to be discharged through this gas hole. Therefore, when gas is generated from the electrode assembly 300, the gas can be discharged to the outside of the battery tank 200 through this gas hole V.

[0058] The top cover 110 can be made of a conductive material, such as a metal, like stainless steel or aluminum.

[0059] The safety vent 120 can be positioned below the top cover 110 so that it is closer to the electrode assembly 300 than the top cover 110. Furthermore, the safety vent 120 can be configured to deform in shape when the internal pressure of the secondary battery, i.e., the internal pressure of the battery canister 200, increases to or exceeds a certain level. For example, the safety vent 120 can be configured to withstand an internal pressure of 15 kgf / cm². 2 or higher than 15 kgf / cm 2 Deformation and cracking occur over time.

[0060] Therefore, as shown in the accompanying drawings, the safety vent 120 can be configured such that its central portion protrudes downwards. Additionally, when gas is generated from inside the secondary battery, i.e., from the electrode assembly 300, to increase the internal pressure of the battery canister 200, the safety vent 120 can deform to protrude upwards while reversing its shape. Specifically, a predetermined notch can be formed near the center of the safety vent 120, and the safety vent 120 can rupture around this notch during deformation. Thus, gas filling the battery canister 200 can be discharged to the outside through the ruptured portion of the safety vent 120.

[0061] The gasket 130 may be configured to surround the edges of the top cover 110 and the safety vent 120, i.e., the outer perimeter. The gasket 130 may be made of an electrically insulating material, such that the edge portions of the top cover 110 and the safety vent 120 are insulated from the battery canister 200. Additionally, the gasket 130 may be made of an impact-resistant, resilient, and durable material to support and protect the cover assembly 100. Therefore, the gasket 130 may be made of, for example, polyolefin or polypropylene. Furthermore, it is preferred that the gasket 130 be bent by machining rather than by heat treatment to prevent a decrease in electrical insulation.

[0062] The shielding member 140 can be placed between the top cover 110 and the safety vent 120. In addition, the edge of the shielding member 140 can be surrounded by a pad 130. That is, the outer perimeter of the top cover 110, the outer perimeter of the shielding member 140, and the outer perimeter of the safety vent 120 can be stacked so that they are in close contact with each other and covered by the pad 130.

[0063] At least a portion of the shielding member 140 may be constructed in a mesh pattern. See also... Figure 4 A more detailed description is given of the specific form of the shielding member 140.

[0064] Figure 4 This is a schematic top view of a shielding member 140 included in a cover assembly 100 according to an embodiment of the present disclosure.

[0065] like Figure 4 As shown, the central portion of the shielding member 140, such as the portion indicated by A1, can be configured in a grid pattern. Here, the grid pattern can be configured such that multiple holes H are formed in the plate-shaped member. Specifically, when the cover assembly 100 is applied to a cylindrical secondary battery, similar to the top cover 110 and the safety vent 120, the shielding member 140 can be configured in a circular plate shape, and multiple holes H can be formed in the central portion of the circular plate. Typically, in the central portion, for example... Figure 4In part A1, the shielding member 140 can be constructed as a grid of different wires orthogonal to each other. In this case, the shielding member 140 can be easily manufactured, and a large number of holes H can be formed while reducing the size of the holes H.

[0066] At the same time, the edge portion of the shielding member 140, for example in Figure 4 The portion indicated by A2 may not be constructed in a mesh form. Furthermore, the shielding member 140 may be surrounded by a pad 130 at its edge portions. That is, the portion of the shielding member 140 through which gas does not pass may not be constructed in a mesh form.

[0067] The shielding member 140 may be made at least partially of a conductive material, such as a metal. The metallic material may include materials such as steel or nickel. Because such steel or nickel materials have a higher melting point than copper or aluminum, they can more stably maintain their shape even if the battery catches fire or explodes.

[0068] Specifically, at least the edge portion of the shielding member 140, as indicated by A2, may be made of a conductive material. The edge portion of the shielding member 140 may be positioned between the edge of the top cover 110 and the edge of the safety vent 120 to serve as an electrical connection path. That is, the top cover 110 and the safety vent 120 may not be in direct contact with each other, but rather be electrically connected through the shielding member 140. Therefore, at least the edge portion of the shielding member 140 may be made of a conductive material.

[0069] According to the configuration of the present disclosure as described above, the cover assembly 100 can be provided with improved safety due to the shielding member 140. Specifically, since at least a portion of the shielding member 140, such as the central portion, is configured in a mesh form, there is no significant obstacle to venting the gas inside the battery canister 200 to the outside when the internal pressure of the battery canister 200 increases and the safety vent 120 ruptures or deforms. However, even during gas venting, the active material inside the battery canister 200 can be prevented from venting to the outside due to the mesh configuration of the shielding member 140. That is, even in the event of a secondary battery fire or explosion, the active material inside the battery canister 200 can be blocked by the shielding member 140. Specifically, when a secondary battery fires or explodes, the temperature of the secondary battery is typically high. Therefore, in this situation, the active material inside the battery canister 200 can be heated to a very high temperature. However, according to the embodiments of the present disclosure, the high-temperature active material can be prevented from venting to the outside of the battery canister 200 due to the shielding member 140. Therefore, it is possible to prevent the active material vented to the outside from damaging surrounding secondary batteries or causing a chain reaction of fires.

[0070] In addition, such as Figure 2 and Figure 3 As shown, the cover assembly 100 according to this disclosure may further include a current interruption member 150.

[0071] The current interrupting member 150 can be configured to have an upper portion and a lower portion, the upper portion being at least partially connected to the lower end of the safety vent 120, and the lower portion being connected to the electrode lead of the electrode assembly 300, such as the positive lead 310. Additionally, the current interrupting member 150 can be configured to block the electrical connection between the electrode assembly 300 and the top cover 110 when the safety vent 120 is deformed. That is, the current interrupting member 150 is positioned between the safety vent 120 and the electrode assembly 300 to electrically connect the electrode assembly 300 to the safety vent 120. The current interrupting member 150 can be referred to as a CID (Current Interrupt Device).

[0072] Therefore, under normal conditions, the current generated from the electrode assembly 300 flows through the positive lead 310 to the current interruption member 150, the safety vent 120, the shielding member 140, and the top cover 110, allowing the secondary battery to be discharged. However, if the internal pressure of the battery increases due to gas generation and the shape of the safety vent 120 is reversed, the contact between the safety vent 120 and the current interruption member 150 is broken or the current interruption member 150 is damaged, thereby interrupting the electrical connection between the safety vent 120 and the electrode assembly 300.

[0073] When the cover assembly 100 includes the current interruption member 150, it may also include an insulating member. The insulating member may be positioned between the safety vent 120 and the current interruption member 150, such that the current interruption member 150 and the safety vent 120 are electrically insulated from each other except for the portion of the central protrusion of the safety vent 120 that contacts the current interruption member 150.

[0074] The shielding member 140 may be at least partially formed into a dome shape. See also... Figure 5 and Figure 6 This will be described in more detail.

[0075] Figure 5 This is a perspective view schematically showing the shielding member 140 included in the cover assembly 100 according to an embodiment of the present disclosure, and Figure 6 It is along Figure 5 The cross-sectional view taken by line B-B'.

[0076] Reference Figure 5 and Figure 6 as well as Figure 3 The shielding member 140 can be formed in a dome shape, with its central portion protruding upwards. Specifically, the shielding member 140 is typically formed in the shape of a circular plate, and its central portion can be configured to... Figure 6 The part indicated by A3 in the middle protrudes upwards in a similar manner.

[0077] Additionally, an empty space may be formed below the upwardly protruding portion of the shielding member 140. That is, when the shielding member 140 is viewed from the safety vent 120, i.e., when the shielding member 140 is viewed from the bottom to the top, it can be considered that the shielding member 140 has an upwardly concave portion.

[0078] According to this configuration of the present disclosure, when gas is discharged to the outside of the battery tank 200 due to a battery explosion or the like, the explosion pressure can be evenly distributed to the dome-shaped shielding member 140. That is, the discharged gas can be evenly ejected from all parts of the shielding member 140, without concentrating on a particular part. Therefore, damage to the shielding member 140 due to the pressure during gas discharge can be prevented.

[0079] Furthermore, according to the embodiment, when the safety vent 120 deforms and protrudes upward due to the increased pressure inside the battery canister 200, the upwardly protruding portion of the safety vent 120 can be inserted into the dome portion of the shielding member 140. Therefore, damage to the shielding member 140 due to the deformation of the safety vent 120 can be prevented.

[0080] Specifically, the shielding member 140 can be configured such that when the safety vent 120 deforms due to an increase in internal pressure, the dome portion forms a predetermined distance from the deformed safety vent 120. (Refer to...) Figure 7 This will be described in more detail.

[0081] Figure 7 This is a schematic cross-sectional view showing the state of the safety vent 120 deformed relative to the cover assembly 100 according to an embodiment of the present disclosure. For this embodiment, features that can be applied in the same or similar manner as described above will not be described in detail, but features that differ from those described above will be described in detail.

[0082] Reference Figure 7 When the internal pressure inside the battery canister 200 increases, the safety vent 120 can deform and protrude upwards as indicated by the arrow. Furthermore, due to this deformation of the safety vent 120, the electrical connection between the current interruption member 150 and the safety vent 120 can be severed. Even when the safety vent 120 is deformed and protruding upwards, the protruding portion of the safety vent 120 and the dome portion of the shielding member 140 can be configured to be spaced apart from each other by a predetermined distance rather than in contact. That is, even if the safety vent 120 protrudes upwards due to the increase in internal pressure inside the battery canister 200, a predetermined distance or greater between the protruding portion and the dome portion of the shielding member 140 can be maintained, as in... Figure 7 As indicated by D.

[0083] According to this configuration of the present disclosure, in the event of, for example, a battery explosion, the shielding member 140 can be stably maintained in its function of blocking the emission of active materials because the shielding member 140 is prevented from being damaged by the safety vent 120.

[0084] The shielding member 140 may include a protrusion. (Refer to...) Figure 8 This will be described in more detail.

[0085] Figure 8 This is a schematic cross-sectional view of some components of the shielding member 140 according to another embodiment of the present disclosure. For example, Figure 8 It can be Figure 6 This is an example of a modification to part C1. Features that differ from previous embodiments will be described in detail regarding this implementation.

[0086] Reference Figure 8 The shielding member 140 may include protrusions on its upper and / or lower surfaces, as indicated by P. For example, the shielding member 140 may include a plurality of upper protrusions formed to project upwards on its upper surface, as indicated by P1. Additionally, the shielding member 140 may include a plurality of lower protrusions formed to project downwards on its lower surface, as indicated by P2.

[0087] Specifically, the protrusion P of the shielding member 140 can be formed as a pin shape with a sharp tip. For example, the upper protrusion P1 of the shielding member 140 can be configured such that at least the upper end gradually thins in the upward direction. Additionally, the lower protrusion P2 of the shielding member 140 can be configured such that at least the lower end gradually thins in the downward direction. Furthermore, the protrusion P of the shielding member 140 can be configured to be located around the hole H of the shielding member 140.

[0088] According to this configuration of the present disclosure, when gas passes through the aperture H of the shielding member 140 in the event of, for example, a battery explosion, it can even prevent active material from passing through the aperture H of the shielding member 140. Specifically, there may be small active materials with a size smaller than the aperture H of the shielding member 140, or some active materials may be drawn into the aperture H of the shielding member 140 due to exhaust pressure. However, in the above configuration, these active materials can be captured by the protrusion P. Therefore, it is possible to prevent active materials from passing through the shielding member 140 and moving toward the top cover 110 and being discharged to the outside of the battery.

[0089] Furthermore, since the active material located inside the shielding member 140 is captured by the lower protrusion P2 of the shielding member 140, the active material can be prevented from passing through the hole H of the shielding member 140 in advance. Additionally, the lower protrusion P2 of the shielding member 140 can prevent the active material from blocking the hole H of the shielding member 140 or from being trapped in the hole H, thereby allowing gas to be smoothly discharged to the outside through the hole H of the shielding member 140. Furthermore, even if the active material located on the lower side of the shielding member 140 passes through the hole H of the shielding member 140, the upper protrusion P1 of the shielding member 140 can still capture the active material again on the upper side before the active material moves towards the top cover 110.

[0090] Therefore, according to this embodiment, the effect of blocking the emission of active materials by the shielding member 140 can be further improved.

[0091] Additionally, the shielding member 140 may include multiple unit shielding members. (Refer to...) Figure 9 This will be described in more detail.

[0092] Figure 9 This is a schematic cross-sectional view of a cover assembly 100 for a secondary battery according to another embodiment of the present disclosure. Features that differ from those of the previous embodiments will be described in detail regarding this embodiment.

[0093] Reference Figure 9 The shielding member 140 may include two unit shielding members, namely an upper shielding member 141 and a lower shielding member 142. Furthermore, the upper shielding member 141 and the lower shielding member 142 may be stacked on top of each other in the vertical direction. Additionally, the upper shielding member 141 and the lower shielding member 142 may be configured to be spaced apart from each other by a predetermined distance in the vertical direction. Specifically, even when the shape of the safety vent 120 is deformed due to increased pressure inside the battery canister 200, the upper shielding member 141 and the lower shielding member 142 may still be configured to be spaced apart from each other by a predetermined distance.

[0094] According to this configuration of the present disclosure, by setting the shielding member 140 as a dual structure, the effect of preventing the emission of active materials can be further improved. That is, when gas is released from the secondary battery, even if some of the heated active material passes through the lower shielding member 142, the active material can still be filtered by the upper shielding member 141.

[0095] like Figure 9As shown, both the upper shield 141 and the lower shield 142 can be configured as upwardly convex dome shapes. Specifically, in this case, the upper shield 141 and the lower shield 142 can be configured such that the dome-shaped portions of the upper shield 141 and the lower shield 142 are inserted into the internal space (lower space) of the top cover 110, which is formed by the upwardly convex protrusion of the top cover 110. In this case, both the upper shield 141 and the lower shield 142 are configured to distribute pressure evenly, while the space for receiving the upper shield 141 and the lower shield 142 is smoothly held inside the cover assembly 100, thereby preventing unnecessary volume increase of the cover assembly 100.

[0096] Furthermore, multiple unit shielding elements can be constructed with different mesh patterns. Here, different mesh patterns can mean different positions, shapes, and numbers of holes forming the mesh. (Refer to...) Figure 10 This will be described in more detail.

[0097] Figure 10 It is shown Figure 9 A magnified view of part of C2.

[0098] Reference Figure 10 The upper shield 141 and the lower shield 142 can be configured such that the holes in the upper shield 141 and the lower shield 142 are located at different positions in the horizontal direction. More specifically, the hole H1 formed in the upper shield 141 and the hole H2 formed in the lower shield 142 can be configured to be located at different positions in the left-right direction (X-axis direction). In this case, in order for the gas that has passed through the hole H2 of the lower shield 142 to pass through the hole H1 of the upper shield 141, the direction of gas movement should be changed, such as by... Figure 10 As indicated by the arrow in the image.

[0099] According to this embodiment of the present disclosure, the gas outflow path between the upper shield 141 and the lower shield 142 can be configured to be curved. Therefore, the filtration effect of the multiple unit shields on the active material can be further improved.

[0100] Furthermore, the upper shield 141 may include a lower protrusion P2 at least on its lower surface, such as in Figure 10 As indicated by P2. Alternatively, the lower shield 142 may include an upper protrusion P1 at least on its upper surface, as shown in... Figure 10 As indicated by P1, at least one of the upper shield 141 and the lower shield 142 may include a protrusion P on the surface facing each other.

[0101] According to this configuration of the present disclosure, even if the active material is introduced into the space between the upper shield 141 and the lower shield 142, the protrusion P can still prevent the active material from easily escaping from the space. Specifically, according to this configuration, the active material between the upper shield 141 and the lower shield 142 can be prevented from easily discharging into the hole H1 of the upper shield 141.

[0102] Furthermore, according to this configuration of the present disclosure, the protrusion P ensures a stable separation between the upper shield 141 and the lower shield 142. Therefore, gas inside the battery tank 200 can be easily discharged to the outside through the upper shield 141 and the lower shield 142.

[0103] Furthermore, even though this embodiment describes multiple unit shields having different grid positions in the horizontal direction, thus forming different grid patterns, different grid patterns can be implemented in various other ways. For example, different grid patterns between unit shields can be implemented with different hole shapes or sizes. Further reference will be made. Figure 11 and Figure 12 This will be described.

[0104] Figure 11 and Figure 12 This is a schematic top view of a shielding member 140 according to another embodiment of the present disclosure.

[0105] First, refer to Figure 11 The shielding member 140 can be configured as a circular plate with its central portion forming a dome shape. In this case, multiple holes H are formed in the dome portion, and each hole H can be circular. Furthermore, Figure 12 and Figure 11 The implementation method is similar, except that the plurality of holes H provided in the shielding member 140 are formed in a rectangular shape instead of a circular shape.

[0106] As described above, the shielding member 140 or the unit shield can be configured to have various mesh patterns. Specifically, when multiple unit shields are included in the cover assembly 100, the unit shields can be configured to have different hole shapes from each other. For example, when the upper shield 141 and the lower shield 142 are included in the shielding member 140, the upper shield 141 can be formed as follows: Figure 4 The shape shown is used, and the lower shield 142 can be formed as shown. Figure 11 The shape shown is used. As another example, the upper shield 141 can be formed as shown in the diagram. Figure 12 The shape shown is used, and the lower shield 142 can be formed as shown. Figure 4 The shape shown.

[0107] According to this configuration of the present disclosure, multiple stacked unit shields can be easily implemented in different mesh forms.

[0108] At the same time, even when a shielding member 140 is included in the cover assembly 100, it is still possible to use, as Figure 11 or Figure 12 as well as Figure 4 The shielding member 140 shown.

[0109] Figure 13 This is a schematic cross-sectional view of the cover assembly 100 according to yet another embodiment of the present disclosure. Features that differ from those of the previous embodiments will be described in detail regarding this embodiment.

[0110] Reference Figure 13 The cover assembly 100 includes an upper shield 141 and a lower shield 142 as multiple unit shields, and both the upper shield 141 and the lower shield 142 can be formed in a dome shape. In this case, the upper shield 141 can be configured to have a dome shape such that at least its central portion protrudes upward. In addition, the lower shield 142 can be configured to have a dome shape such that its central portion protrudes downward.

[0111] In this configuration, the upper shield 141 can be configured such that at least a portion of the dome-shaped structure is inserted into the concave portion of the top cover 110. That is, the top cover 110 is formed to bulge upwards, and when viewed from below, the concave portion can be considered to be formed at the top cover 110. In this configuration, the upper shield 141 can be positioned below the top cover 110, and at least a portion of the upper shield 141 can be inserted into the concave portion of the top cover 110.

[0112] Furthermore, the lower shield 142 can be configured such that at least a portion of the dome-shaped structure is inserted into the concave portion of the safety vent 120. That is, the safety vent 120 is formed to bulge downwards in the normal state, and when viewed from above, the concave portion can be considered to be formed at the safety vent 120. Additionally, the lower shield 142 can be positioned above the safety vent 120, and at least a portion of the lower shield 142 can be inserted into the concave portion of the safety vent 120.

[0113] According to this configuration of the present disclosure, even if multiple unit shields are included as shielding members 140 in the cover assembly 100, the increase in volume of the cover assembly 100 can still be minimized due to the unit shields. Furthermore, according to this embodiment, the spacing between the unit shields can be safely ensured under normal conditions.

[0114] In the above embodiments, the lower shield 142 can be configured such that the convex shape reverses from the bottom to the top due to the deformation of the safety vent 120. That is, when gas is discharged from the inside of the battery can 200 to the outside due to the increase in internal pressure of the battery can 200, the safety vent 120 can be reversed to convex upwards, such as... Figure 7 The protrusion shown is illustrated. At this time, the lower shield 142 can be configured such that when the safety vent 120 is reversed, the lower shield 142 reverses from a downwardly protruding shape to an upwardly protruding shape in a manner similar to that of the safety vent 120. Specifically, the lower shield 142 can be deformed from a downwardly protruding shape to an upwardly protruding shape by the pushing force generated when the safety vent 120 is reversed. For example, when the safety vent 120 is deformed as shown... Figure 7 When the lower shield 142 protrudes upward as shown, it can be configured to deform as follows: Figure 9 The ground bulges upwards as shown.

[0115] According to this implementation configuration of the present disclosure, in an emergency situation involving gas emission, the deformation operation of the safety vent 120 can be prevented from being interfered with by the lower shield 142. Furthermore, according to this embodiment, even in an emergency, the lower shield 142 is formed into a dome shape, allowing the gas ejection pressure to be evenly distributed across the entire lower shield 142.

[0116] In addition, in the above configuration, the lower shield 142 can be configured such that at least some holes are located in different positions in the horizontal direction from the holes of the upper shield 141 when the convex shape is reversed.

[0117] For example, when the safety vent 120 and the lower shield 142 bulge upwards due to gas ejection, some or all of the holes H2 formed in the lower shield 142 may be located in a different position in the horizontal direction (left-right direction in the figures) than the holes H1 in the upper shield 141, such as... Figure 10 As shown.

[0118] According to this embodiment of the present disclosure, as referred to above... Figure 10 As described above, when gas is emitted, a curved portion is formed in the gas emission path, thereby further improving the filtration effect of the shielding member 140 on the active material.

[0119] In addition, in the above configuration, the lower shield 142 can be configured such that at least a portion of the lower shield 142 is spaced apart from the upper shield 141 by a predetermined distance when the convex shape is reversed.

[0120] For example, in the reverse upward convex state of the lower shield 142, the lower shield 142 and the upper shield 141 can be configured to be spaced apart from each other by a predetermined distance. That is, the lower shield 142 and the upper shield 141 can be configured such that even in an abnormal state where gas is discharged, the central portions of the lower shield 142 and the upper shield 141, except for the portion covered by the gasket 130, will not come into direct contact with each other.

[0121] According to this configuration of the present disclosure, when gas is discharged, the gas in the space between the upper shield 141 and the lower shield 142 can be smoothly discharged. That is, when gas is discharged, even if the distance between the lower shield 142 and the upper shield 141 decreases due to the reverse shape of the lower shield 142, a certain space can still be ensured so that gas discharge is not disturbed. Therefore, the effect of improving battery safety according to the present disclosure can be reliably ensured.

[0122] A battery pack according to this disclosure may include at least one secondary battery as described above. Specifically, when multiple secondary batteries are included in the battery pack, each secondary battery may include a cover assembly 100 according to this disclosure. Therefore, even if any one secondary battery explodes or catches fire, it is possible to prevent a chain reaction of fires in other secondary batteries.

[0123] At the same time, although directional terms such as “up,” “down,” “left,” and “right” have been used in this specification, it will be apparent to those skilled in the art that these terms are for ease of interpretation only and may be expressed differently depending on the observer’s position or the position of the object.

[0124] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of illustration only, as various variations and modifications within the scope of this disclosure will become apparent to those skilled in the art based on this detailed description.

[0125] Explanation of reference numerals in the attached figures

[0126] 100: Cover component

[0127] 110: Top Cover

[0128] 120: Safety Vent

[0129] 130: Padding

[0130] 140: Shielding components

[0131] 141: Upper shielding component; 142: Lower shielding component

[0132] 150: Current interruption component

[0133] 200: Battery Canister

[0134] 300: Electrode assembly

[0135] 310: Positive lead

Claims

1. A cover assembly for a secondary battery, the cover assembly being coupled to an open end of a battery canister, the cover assembly comprising: A top cover, which is provided in a protruding form on the uppermost portion of the cover assembly to form a positive terminal; A safety vent is provided below the top cover to deform its shape when the internal pressure of the battery can increases. A liner configured to surround the edge of the top cover and the edge of the safety vent; as well as A shielding member, positioned between the top cover and the safety vent and having an edge surrounded by the padding, the shielding member being at least partially constructed in a mesh form. The shielding component comprises multiple unit shielding elements stacked on top of each other in the vertical direction, and The upper shielding member of the plurality of unit shielding members is formed in a dome shape, such that at least the central part protrudes upward, and the lower shielding member of the plurality of unit shielding members is formed in a dome shape, such that at least the central part protrudes downward.

2. The cover assembly for a secondary battery according to claim 1, further comprising: A current interruption member having an upper portion and a lower portion, the upper portion being connected to the lower end of the safety vent, the lower portion being connected to an electrode assembly, and the current interruption member being configured to interrupt the electrical connection between the electrode assembly and the top cover when the safety vent is deformed.

3. The cover assembly for a secondary battery according to claim 1, in, The shielding member includes a protrusion formed to project upwards or downwards.

4. The cover assembly for a secondary battery according to claim 1, in, The multiple unit shields are configured with different mesh patterns from each other.

5. The cover assembly for a secondary battery according to claim 1, in, The lower shield is configured such that the convex shape of the lower shield changes from a downward direction to an upward direction due to the deformation of the safety vent.

6. The cover assembly for a secondary battery according to claim 5, in, The lower shield is configured such that, when the convex shape is reversed, at least some of the holes formed in the lower shield are located in a different position in the horizontal direction than the holes formed in the upper shield.

7. A secondary battery comprising a cover assembly for a secondary battery according to any one of claims 1 to 6.

8. A battery pack comprising at least one secondary battery according to claim 7.

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