Secondary battery

Abstract

A secondary battery includes: an electrode assembly; a housing housing the electrode assembly; and a cover covering an open portion of the housing, wherein one of the housing and the cover includes a vent on its outer surface, the vent including a recess, the recess including a first recess and a second recess, the first recess extending from a central portion of the vent in a first direction, the second recess including: a first region extending from the central portion in the first direction; and a second region extending from the first region in a direction different from the first direction, and the first recess being inside the first region.

Description

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2024-0190606, filed on December 18, 2024, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] One or more embodiments relate to secondary batteries. Background Technology

[0004] Unlike primary batteries, which are not designed for recharging, secondary batteries are designed for both charging and discharging. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as energy sources to power motors in hybrid vehicles, electric vehicles, and other similar applications, and also as batteries for energy storage. Such secondary batteries include electrode assemblies with positive and negative electrodes, a housing containing the electrode assemblies, and electrode terminals connected to the electrode assemblies.

[0005] The information disclosed in this background is intended only to improve the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art. Summary of the Invention

[0006] An embodiment includes a secondary battery comprising: an electrode assembly; a housing housing the electrode assembly; and a cover covering an open portion of the housing, wherein one of the housing and the cover includes an exhaust portion on its outer surface, the exhaust portion including a recess, the recess including a first recess and a second recess, the first recess extending from a central portion of the exhaust portion in a first direction, the second recess including: a first region extending from the central portion in the first direction; and a second region extending from the first region in a direction different from the first direction, and the first recess being inside the first region.

[0007] The second notch may be less deep than the first notch.

[0008] The depth difference between the first notch and the second notch can be less than 20% of the thickness of the shell.

[0009] The length of the first notch can be less than 1 / 3 of the length of the first region.

[0010] The depth of the first notch can be 70% to 85% of the thickness of the shell.

[0011] The depth of the second notch can be 50% to 70% of the thickness of the shell.

[0012] The notch may further include a groove in the central portion of the exhaust portion, and the groove may extend in the first region to increase the width of the first region.

[0013] The notch may further include a third notch surrounding the second notch, the ends of the second region may be connected by the third notch surrounding the second notch, and the third notch may be less deep than the second notch.

[0014] The depth of the third notch can be 20% to 50% of the thickness of the shell.

[0015] The width of the third notch can be greater than the width of the first notch, and the width of the second notch can be greater than the width of the third notch.

[0016] An embodiment includes a secondary battery comprising: an electrode assembly; a housing housing the electrode assembly; and a cover covering an open portion of the housing, wherein one of the housing and the cover includes an exhaust portion on its outer surface, the exhaust portion including a notch comprising a first notch, a second notch, and a third notch, the first notch extending from a central portion of the exhaust portion in a first direction, the second notch including: a first region extending from the central portion in the first direction; and a second region extending from the first region in a direction different from the first direction, the third notch surrounding the second notch, and each end of the second region being connected via the third notch surrounding the second notch.

[0017] The first notch may be inside the first region.

[0018] The depth difference between the first notch and the second notch can be less than 20% of the thickness of the shell.

[0019] The length of the first notch can be less than 1 / 3 of the length of the first region.

[0020] The depth of the first notch can be 70% to 85% of the thickness of the shell.

[0021] The depth of the second notch can be 50% to 70% of the thickness of the shell.

[0022] The depth of the third notch can be 20% to 50% of the thickness of the shell.

[0023] The width of the third notch can be greater than the width of the first notch, and the width of the second notch can be greater than the width of the third notch.

[0024] The notch may further include a groove in the central portion of the exhaust portion, and the groove may extend in the first region to increase the width of the first region.

[0025] The second notch may be less deep than the first notch, and the third notch may be less deep than the second notch. Attached Figure Description

[0026] Features will become apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, in which:

[0027] Figure 1 This is a schematic perspective view of an example of a secondary battery according to one embodiment;

[0028] Figure 2 It is along Figure 1 A schematic cross-sectional view of an example section taken by line III-III';

[0029] Figure 3 This is a schematic plan view of an example of the venting section of a secondary battery according to one embodiment;

[0030] Figure 4 This is a schematic plan view of an example of the venting section of a secondary battery according to another embodiment;

[0031] Figure 5 This is an enlarged perspective view of an example of the venting section of a secondary battery according to another embodiment;

[0032] Figures 6A to 6C This is a sequential view of the operation of the venting section of a secondary battery according to one embodiment; and

[0033] Figures 7A to 7C This is a view of a modified example of a notch formed on the vent of a secondary battery according to an embodiment. Detailed Implementation

[0034] Exemplary embodiments will now be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey exemplary implementation methods to those skilled in the art.

[0035] In the drawings, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as "on" another layer or substrate, it may be directly on the other layer or substrate, or an intermediary layer may also be present. Furthermore, it will be understood that when a layer is referred to as "below" another layer, it may be directly below the other layer, and one or more intermediary layers may also be present. Additionally, it will be understood that when a layer is referred to as "between" two layers, it may be the only layer between the two layers, or one or more intermediary layers may also be present. Similar reference numerals always refer to similar elements.

[0036] The terms or words used in this specification and claims should not be construed as limited to their general or dictionary meanings, and should be interpreted as conforming to the meaning and concept of the technical idea of ​​this disclosure, based on the principle that the inventor is capable of appropriately defining the terms and concepts to best interpret his or her own disclosure. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of this disclosure and do not represent all the technical ideas of this disclosure. It should be understood that various equivalents and modifications may exist to replace these embodiments at the time of filing this application.

[0037] The terms “comprising” and / or “including” as used herein indicate the presence of stated features, quantities, steps, operations, components, elements and / or groups thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements and / or groups thereof.

[0038] Although the terms first, second, etc., may be used herein to describe various components, these components are not limited by these terms. These terms are used only to distinguish one component from another, and unless otherwise stated, the first component may of course also be the second component in this case.

[0039] Throughout this specification, unless otherwise stated, each component may be singular or plural.

[0040] The phrase "any configuration is placed "above (or below)" or "on" a component can mean not only that the arbitrary configuration is placed in contact with the upper (or lower) surface of the component, but also that other configurations may be located between the component and the arbitrary configuration placed on (or below) the component.

[0041] Furthermore, when a component is described as being “connected,” “joined,” or “fastened” to another component, these components may be directly connected to each other or be able to be connected to each other; however, it should also be understood that an additional component may be “between” these two components, or that these two components may be “connected,” “joined,” or “fastened” through that additional component. When referring to one part being electrically connected to another part, this includes not only cases where they are directly connected, but also cases where they are connected using another element between them.

[0042] Figure 1 This is a schematic perspective view of an example of a secondary battery according to one embodiment, and Figure 2 It is along Figure 1 A schematic cross-sectional view of an example section taken by line III-III'.

[0043] refer to Figure 1 and Figure 2 According to one embodiment, the secondary battery 10 may include an electrode assembly 210, a terminal portion 11 and a terminal portion 12 respectively electrically connected to the electrode assembly 210, a housing 15 for accommodating the electrode assembly 210, and a cover plate 17 covering the upper portion (e.g., the open portion) of the housing 15.

[0044] An example description will be given in which the secondary battery 10 according to one embodiment is a lithium-ion battery cell having a prismatic (e.g., parallelepiped) shape. However, this disclosure can also be applied to various types of battery cells, such as lithium polymer battery cells or cylindrical battery cells.

[0045] Terminal portions 11 and 12 may include a first terminal 11 and a second terminal 12 with different polarities. For example, if the first terminal 11 is a positive electrode terminal, the second terminal 12 may be a negative electrode terminal, and in another example, if the first terminal 11 is a negative electrode terminal, the second terminal 12 may be a positive electrode terminal. For example, the first terminal 11 and the second terminal 12 may be formed with different polarities, and may not have a specific polarity.

[0046] The secondary battery 10 may include: at least one of an electrode assembly 210 wound with a separator 213 as an insulator, the separator 213 being located between a positive electrode 211 and a negative electrode 212; and a housing 15 wherein the electrode assembly 210 is constructed (e.g., accommodated). The electrode assembly 210 may undergo an electrochemical reaction with an electrolyte to generate energy.

[0047] After the diaphragm 213, which serves as an insulator, is placed between the positive electrode 211 and the negative electrode 212, the positive electrode 211 and the negative electrode 212 can be wound together. However, the electrode assembly 210 described above can be formed in a structure in which the positive electrode 211 and the negative electrode 212, each comprising multiple sheets, are alternately stacked using the diaphragm 213 placed between the positive electrode 211 and the negative electrode 212.

[0048] The positive electrode 211 and the negative electrode 212 in the current collector formed of a thin metal foil may respectively include a coated portion and an uncoated portion 211a and 212a. The coated portion may be coated with an active material, and the uncoated portions 211a and 212a may not be coated with an active material.

[0049] The housing 15 can form the overall appearance of the secondary battery 10 and can provide space therein to house the electrode assembly 210. The housing 15 can be made of a conductive metal, such as aluminum, aluminum alloy, or nickel-plated steel.

[0050] The secondary battery 10 may include a cover 17 that covers an opening (e.g., an open portion) of the housing 15. The housing 15 and the cover 17 may contain a conductive material. Here, a first terminal 11 and a second terminal 12 electrically connected to the positive electrode 211 or the negative electrode 212 may be mounted to protrude outward through the cover 17.

[0051] For example, the outer peripheral surfaces of the upper supports of the first terminal 11 and the second terminal 12 that protrude outward from the cover plate 17 may be threaded and may be secured to the cover plate 17 by using a nut. However, the first terminal 11 and the second terminal 12 may be formed as a riveting structure for being riveted, or may be welded to the cover plate 17.

[0052] The cover plate 17 may be a thin plate and may be connected to an opening in the housing 15. An electrolyte injection opening 14, in which a sealing cap may be installed, may be formed in the cover plate 17.

[0053] The first terminal 11 and the second terminal 12 can be electrically connected to a current collector, which includes a first current collector 240 and a second current collector 250 (hereinafter referred to as the positive electrode current collector and the negative electrode current collector) soldered to the uncoated portion 211a of the positive electrode terminal or the uncoated portion 212a of the negative electrode terminal.

[0054] For example, the first terminal 11 and the second terminal 12 can be connected to the positive electrode current collector 240 and the negative electrode current collector 250 by welding, respectively. However, the first terminal 11 and the second terminal 12 can also be integrally formed with the positive electrode current collector 240 and the negative electrode current collector 250, respectively.

[0055] In some embodiments, an insulating member may be installed between the electrode assembly 210 and the cover plate 17. Here, the insulating member may include a first lower insulating member 260 and a second lower insulating member 270. The first lower insulating member 260 and the second lower insulating member 270 may each be installed between the electrode assembly 210 and the cover plate 17.

[0056] According to one embodiment, the separator can be installed between the insulating member and the first terminal 11 and the second terminal 12 in such a way that one end of each separator is arranged opposite to a corresponding side surface of the electrode assembly 210, and the separator may include a first separator 280 and a second separator 290. Accordingly, one end of the first separator 280 and one end of the second separator 290, respectively arranged opposite to the corresponding side surface of the electrode assembly 210, can be arranged between the first lower insulating member 260 and the first terminal 11 and between the second lower insulating member 270 and the second terminal 12, respectively.

[0057] This allows the first terminal 11 and the second terminal 12, which are respectively soldered to the positive electrode current collector 240 and the negative electrode current collector 250, to the corresponding ends of the first lower insulating member 260 and the second lower insulating member 270, as well as the first separator member 280 and the second separator member 290.

[0058] In some embodiments, the secondary battery 10 according to one embodiment may include a venting section 13. During charging or discharging of the secondary battery 10, the active materials and electrolyte may deteriorate or decompose due to abnormal external environments, thereby generating gas. The generated gas may increase the internal pressure of the secondary battery 10, causing further rapid deterioration.

[0059] The exhaust section 13 can be a region that discharges internal gas to the outside of the secondary battery 10, and can improve the safety of the secondary battery 10 against heat transfer and fire.

[0060] The vent 13 may be positioned on the housing 15 housing the electrode assembly 210, or on a cover 17 covering the upper portion (e.g., an open portion) of the housing 15. In one embodiment, one of the housing 15 and the cover 17 includes the vent 13 on its outer surface. For example, the vent 13 may be located between a first terminal 11 and a second terminal 12 on the terminal portion of the cover 17. As another example, the vent 13 may be located on the lower surface of the housing 15, each of the two opposing side surfaces, or one side surface. The shape of the vent 13 (including its size and location) may vary from other vent 13. Figure 1 and Figure 2 The shape shown in the image.

[0061] Figure 3This is a schematic plan view of an example of the venting section of a secondary battery according to one embodiment, and Figure 4 This is a schematic plan view of an example of the venting section of a secondary battery according to another embodiment.

[0062] refer to Figure 3 and Figure 4 According to one embodiment, the secondary battery may include a venting section 13. In the event that the secondary battery catches fire (e.g., ignition and / or gas generation) due to repeated charging and discharging, the gas generated inside the secondary battery can be discharged to the outside through the venting section 13. The venting section 13 can suppress the spread of fire and thermal runaway by discharging gas and heat, thereby improving the safety of the secondary battery.

[0063] The vent 13 may include a recess formed to a certain depth from the outer surface of the housing 15 or the cover 17. The area of ​​the vent 13 with the recess may be thinner than other areas of the housing 15 or the cover 17, and the area of ​​the vent 13 with the recess, which is thinner than other areas of the housing 15 or the cover 17, may break preferentially when the internal pressure of the secondary battery increases.

[0064] In the event of thermal runaway, high-temperature and high-pressure gases can be generated, which may increase the internal pressure of the secondary battery, causing the casing 15 to tear or the secondary battery to explode. According to one embodiment, the secondary battery may include a vent 13 with notches formed therein, thereby allowing internal gases and heat to be discharged to the outside by operating the vent 13, and reducing the risk of thermal runaway (which is a series of explosions).

[0065] In some embodiments, the notch may include a first notch 100 and a second notch 200.

[0066] The first notch 100 may extend from the center portion of the exhaust portion 13 in a first direction. For example, the first direction may be the same as the longitudinal direction of the exhaust portion 13, and the first notch 100 may be formed parallel to the longitudinal direction of the exhaust portion 13.

[0067] The thickness of the vent 13 in the area where the first notch 100 is formed can be thinner than the thickness in other areas of the housing 15 or the cover plate 17. Therefore, under increased internal pressure, the vent 13 can easily rupture along the first notch 100. The rupture of the first notch 100 creates a space, through which gas and heat can be smoothly discharged from the interior of the secondary battery, thereby improving the safety of the secondary battery.

[0068] For example, the first notch 100 can be formed in a region exhibiting maximum strain due to increased internal pressure in the secondary battery. The secondary battery 10, including the housing 15, can expand due to internally generated gas and heat. In this case, the first notch 100 can be located in a region exhibiting maximum strain due to expansion, thereby allowing stress generated by internal pressure to concentrate in the region where the first notch 100 is formed. For example, the first notch 100 can be formed in a region subjected to maximum tensile stress, and tensile failure can occur.

[0069] By forming the first notch 100 in the region exhibiting the maximum strain, the operation of the venting section 13 can be performed quickly, and the explosion or thermal runaway of the secondary battery can be delayed or suppressed.

[0070] The second recess 200 may include: a first region 201 extending from the center portion of the exhaust portion 13 in a first direction; and a second region 202 extending from the first region 201 in a direction different from the first direction. For example, the first direction may be the same as the longitudinal direction of the exhaust portion 13, and the first region 201 of the second recess 200 may be parallel to the first recess 100 in the longitudinal direction of the exhaust portion 13.

[0071] In this case, the first notch 100 may be located inside the first region 201. The region in which the first notch 100 is formed may overlap with the first region 201 of the second notch 200, and may be defined such that the first notch 100 is located inside the second notch 200 (e.g., inside the first region 201).

[0072] For example, the first notch 100 may be formed to have a certain depth from the lower surface of the second notch 200 toward the inner surface of the housing 15. For example, after the first region 201 of the second notch 200 is formed, the first notch 100 may be formed in a portion of the first region 201 by an additional forging process.

[0073] With the first notch 100 positioned inside the first region 201 to overlap with the second notch 200, the thickness of the vent portion 13 in the region where the first notch 100 and the second notch 200 are formed can be thinner than the thickness in other regions of the housing 15 or the cover plate 17. Accordingly, the vent portion 13 including the first notch 100 and the second notch 200 can be broken by a smaller force to ensure a gas flow path and suppress further degradation, thereby enhancing the safety of the secondary battery.

[0074] By forming a first notch 100 in the first region 201 and allowing the rupture and opening of the exhaust section 13 to occur from the first notch 100, the rupture of the exhaust section 13 can occur in the first region 201 before the rupture occurs in the second region 202, and the rupture conditions can be controlled by promoting the sequential rupture of the exhaust section 13.

[0075] The length L1 of the first notch 100 can be less than one-third of the length L2 of the first region 201. The first notch 100 can be formed in the first region 201, thereby being located in the second notch 200. The longer the length L1 of the first notch 100, the faster the exhaust section 13 can be operated (e.g., ruptured), and the more smoothly the gas and heat can be discharged through the space formed by the rupture of the first notch 100, thereby reducing the risk of thermal runaway propagation.

[0076] However, when the length L1 of the first notch 100 exceeds one-third of the length L2 of the first region 201, the following problems may exist: such as the exhaust 13 rupturing even under pressure lower than the internal pressure set for the rupture of the exhaust 13, or foreign objects passing through the exhaust 13.

[0077] Accordingly, the secondary battery according to another embodiment can be configured such that the length L1 of the first notch 100 is less than 1 / 3 of the length L2 of the first region 201, thereby ensuring the safety and reliability of the secondary battery while ensuring its durability by controlling the pressure conditions that cause the vent 13 to rupture.

[0078] In some embodiments, the second region 202 of the second notch 200 may extend from the first region 201 in a direction different from the first direction. The second region 202 may extend from each of one end and the other end of the first region 201. The second region 202 may extend from each of one end and the other end of the first region 201 to form a plurality of second regions 202.

[0079] For example, a plurality of second regions 202 extending from one end of the first region 201 may extend upward in a second direction and a third direction different from the first direction, and a plurality of second regions 202 extending from the other end of the first region 201 may extend in a fourth direction and a fifth direction different from the first direction. The second to fifth directions may be the same or different directions, and the plurality of second regions 202 may be positioned symmetrically or asymmetrically with respect to the central portion.

[0080] After the first notch 100 and the first region 201 break sequentially, the second region 202 can break. The second region 202 can expand the rupture area, allowing the high-temperature and high-pressure gases generated inside the secondary battery to escape smoothly, and can extend in a direction different from that of the first region 201, thus breaking with less force. Therefore, the venting section 13 can operate quickly to suppress the explosion of the secondary battery.

[0081] For example, the second region 202 can extend from one end of the first region 201 to form a plurality of second regions 202, and as a specific example, it can extend from one end of the first region 201 in a V-shape. As the ruptured area and open space along the second region 202 increase, gas and heat can be rapidly discharged from the interior of the secondary battery, thereby reducing the risk of thermal runaway.

[0082] The notch may further include a third notch 300, which surrounds the second notch 200 by connecting the ends of the plurality of second regions 202. The third notch 300 may be formed around the second notch 200 to prevent rupture or separation of the exhaust section 13 from any region other than the exhaust section 13. While discharging gas and heat through the space created by the rupture of the first notch 100 and the second notch 200, the third notch 300 can stably hold the exhaust section 13.

[0083] The third notch 300 can be formed along the boundary of the vent 13, and the size of the rupture or opening of the vent 13 can be determined according to the internal pressure of the secondary battery. The size of the vent 13, determined along the boundary of the vent 13, can vary depending on, for example, the battery material, the generated flow rate, the battery shape, etc.

[0084] In some embodiments, the width W3 of the third notch 300 may be greater than the width W1 of the first notch 100, and the width W2 of the second notch 200 may be greater than the width W3 of the third notch 300. The width of the notches provides space in which the vent 13 will be opened to release gas and heat. If the width of each notch is narrower than a certain width, it may be difficult to ensure the space required to open the vent 13. In another example, if the width of each notch is greater than a certain width, it may be difficult to protect the secondary battery and maintain the strength and durability of the housing 15.

[0085] The first notch 100 can be located in the first region 201, and the width W1 of the first notch 100 can be narrower than the width W2 of the second notch 200. This allows the first notch 100 to be formed inside the second notch 200. For example, an additional forging process can be performed on a portion of the first region 201 to form a narrow and deep first notch 100 inside the second notch 200. The first notch 100 can increase the depth of a portion of the region in which the second notch 200 is formed, and the vent 13 can be operated quickly, resulting in improved safety of the secondary battery. By allowing the first region 201 to fracture earlier than the second region 202, the first notch 100 can induce sequential fracture and control the fracture conditions.

[0086] The width W2 of the second notch 200 can be greater than the width W1 of the first notch 100 and the width W3 of the third notch 300. The wider width of the second notch 200 can facilitate the rupture and opening of the exhaust section 13. The second notch 200 can be ruptured along with the rupture of the first notch 100, and can increase the rupture area and open space of the exhaust section 13. The open space of the exhaust section 13 extending along the second notch 200 can serve as a path for gas exhaust and heat dissipation, thereby inhibiting heat propagation and ignition.

[0087] The width W3 of the third notch 300 may be narrower than the width W2 of the second notch 200. The third notch 300 may be formed along the boundary of the exhaust portion 13 to suppress breakage in the area outside the exhaust portion 13, thereby determining the size of the exhaust portion 13. The width W3 of the third notch 300 may be set such that the exhaust portion 13 can maintain stable operation without separation while gas and heat are being discharged.

[0088] In some embodiments, the notch may further include a groove 400 formed in the central portion of the exhaust portion 13 by increasing the width of the first region 201. The groove 400 may be formed in a shape in which the first region 201 extends from the central portion, and for example, may have a circular shape centered on the central portion of the exhaust portion 13. Additionally, refer to... Figure 3 The width of the first region 201 can correspond to the width W2 of the second notch 200.

[0089] In this case, the groove 400 can be formed in a region where stress is concentrated due to the internal pressure of the secondary battery. For example, the secondary battery may expand due to gas and heat, and the region of stress concentration may exhibit the maximum strain caused by the expansion. The groove 400 can be formed in the region subjected to the maximum tensile stress, and tensile failure may occur.

[0090] When the internal pressure of the secondary battery increases, the groove 400 formed in the central portion of the vent 13 may be the first part to rupture due to the high temperature and high pressure gas, and the vent 13 can open from the groove 400. The secondary battery according to this embodiment can control the operation of the vent 13 by concentrating stress on the groove 400 formed in the recess, thereby ensuring safety and reliability.

[0091] According to one embodiment, the groove 400 may be formed in the central portion of the vent 13 in a shape that increases in width with respect to the first region 201. In other words, the groove 400 extends in the first region 201 to increase the width of the first region 201, and the first recess 100 may be positioned in the first region 201 and may extend from the central portion (e.g., on both sides of the groove 400). Accordingly, the first recess 100 may be positioned to pass through the groove 400 formed in the central portion of the vent 13, and the area where the first recess 100 and the groove 400 overlap with each other may be the area exhibiting the maximum stress generated by the expansion of the secondary battery. In the event of a secondary battery fire (e.g., ignition and / or gas generation), the groove 400 and the first recess 100 may rapidly operate the vent 13 and suppress strain or bursting of the secondary battery.

[0092] Figure 5 This is an enlarged perspective view of the venting section of a secondary battery according to another embodiment.

[0093] refer to Figure 5 According to another embodiment, the secondary battery may include an exhaust portion 13 in which notches are formed. The first notch 100, the second notch 200, and the third notch 300 may have different depths, thus the exhaust portion 13 may have different thicknesses in each region where the notches are formed. In this case, the thickness of the exhaust portion 13 in the region where the notches are formed may be the thickness from the lowest point of the notch to the inner surface of the housing 15, while the thickness of the exhaust portion 13 in the region where no notches are formed may be the same as the thickness T of the housing 15.

[0094] The area in which the notch is formed in the vent 13 may have a thinner thickness than other areas of the housing 15 or cover 17. In the case where the vent 13 is thin due to the depth of the notch, the vent 13 may rupture and open first due to the gas and heat generated by the increased internal pressure of the secondary battery.

[0095] In this embodiment, for ease of explanation, the thickness of the exhaust portion 13 in the region where the first recess 100 is formed can be referred to as the first thickness T1, the thickness of the exhaust portion 13 in the region where the second recess 200 is formed can be referred to as the second thickness T2, and the thickness of the exhaust portion 13 in the region where the third recess 300 is formed can be referred to as the third thickness T3.

[0096] The depth T-T1 of the first notch 100 (e.g., T minus T1) can be 70% to 85% of the thickness T of the housing 15. For example, the first thickness T1 can be 15% to 30% of the thickness T of the housing 15. If the first thickness T1 is less than 15% of the thickness T of the housing 15, the thickness of the exhaust portion 13 may be too thin. This could cause the exhaust portion 13 to rupture even under low internal pressure. In another example, if the first thickness T1 exceeds 30% of the thickness T of the housing 15, rapid operation of the exhaust portion 13 may not be permitted. This could limit the timely discharge of gas and heat.

[0097] The depth T-T2 of the second notch 200 can be 50% to 70% of the thickness T of the housing 15. For example, the second thickness T2 can be 30% to 50% of the thickness T of the housing 15. If the second thickness T2 is less than 30% of the thickness T of the housing 15, the exhaust section 13 may rupture even at a pressure lower than the internal pressure set to cause the exhaust section 13 to rupture. In another example, if the second thickness T2 exceeds 50% of the thickness T of the housing 15, it may be difficult to expand the rupture area and open space of the exhaust section 13.

[0098] The depth T-T3 of the third notch 300 can be 20% to 50% of the thickness T of the housing 15. For example, the third thickness T3 can be 50% to 80% of the thickness T of the housing 15. If the third thickness T3 is less than 50% of the thickness T of the housing 15, the following problems may occur: any area other than the exhaust vent 13 may crack due to the exhaust gas, or the housing 15 may be torn and the exhaust vent 13 may separate. In another example, if the third thickness T3 exceeds 80% of the thickness T of the housing 15, it may be difficult to provide space in which the exhaust vent 13 will be opened to exhaust gas and heat.

[0099] In this case, the depth difference between the first notch 100 and the second notch 200 can be less than 20% of the thickness T of the housing 15. For example, the difference between the first thickness T1 and the second thickness T2 can be less than 20% of the thickness T of the housing 15. If the difference between the first thickness T1 and the second thickness T2 exceeds 20% of the thickness T of the housing 15, it may be difficult to design notches that satisfy the sequential fracture of the first notch 100 and the second notch 200 and the desired fracture pressure, and the durability of the secondary battery may be problematic.

[0100] The secondary battery according to this embodiment may include a venting section 13, which includes notches of different depths, so that the operation of the venting section 13 can be controlled by controlling the pressure conditions under which the venting section 13 ruptures. The difference in notch depth can cause sequential rupture and allow for the stable discharge of gas and heat, thereby improving the safety of the secondary battery.

[0101] Compared to configurations that include separate vents, the secondary battery according to this embodiment simplifies the manufacturing process. For example, the notch can be formed by a forging process, and as a specific example, the housing 15 can be molded and manufactured by a first forging to form a third notch 300, a second forging to form a second notch 200, and a third forging to form a first notch 100. The secondary battery according to this embodiment can reduce manufacturing costs by integrally designing and manufacturing the vent 13 in the housing 15, and can control rupture conditions while maintaining the high strength and durability of the secondary battery including the housing 15.

[0102] Figures 6A to 6C This is a sequential view of the operation of the venting section of a secondary battery according to one embodiment.

[0103] refer to Figures 6A to 6C According to one embodiment, a secondary battery may include an exhaust portion 13 in which a notch is formed, and may further include a groove 400 formed in the central portion of the exhaust portion 13 by increasing the width of the first region 201.

[0104] In the event that the temperature of the secondary battery rises due to a thermal event and gas is generated inside, the exhaust section 13 can serve as a path for discharging the gas and heat.

[0105] The first notch 100 may be formed on the central portion of the exhaust section 13 to have a depth greater than that of the second notch 200 and the third notch 300, and may be located in the region of stress concentration caused by internal pressure, thereby causing it to break first. The first notch 100 may be positioned to pass through the groove 400 formed in the central portion of the exhaust section 13, and the region where the first notch 100 and the groove 400 overlap with each other may be the region in which the maximum strain caused by the expansion of the secondary battery is exhibited.

[0106] The first notch 100 can break from the center portion where the groove 400 is formed, and then the first region 201 can break along the already broken first notch 100. The vent 13 of the already broken first region 201 can be opened due to the internal gas, and the gas and heat can be discharged through the open space, thereby reducing the risk of explosion and thermal runaway of the secondary battery.

[0107] Subsequently, the exhaust section 13 can be opened along the second region 202. The second region 202 can extend from each of one end and the other end of the first region 201 to become a plurality of second regions 202, and can increase the rupture area and open space of the exhaust section 13.

[0108] The first region 201 and the second region 202 can be opened sequentially to release gas and heat, thereby delaying and suppressing a series of explosions in the secondary battery. The third notch 300 can be formed along the boundary of the exhaust section 13 and can maintain the exhaust section 13 so that the exhaust section 13 can operate stably without separation.

[0109] The secondary battery according to this embodiment can control rupture conditions, such as rupture sequence and pressure, to suppress further rapid degradation and improve the safety of the secondary battery for heat transfer and ignition.

[0110] Figures 7A to 7C This is a view of a modified example of a notch formed on the vent of a secondary battery according to an embodiment.

[0111] refer to Figures 7A to 7C A secondary battery according to one embodiment may include an exhaust portion in which a notch is formed, and may further include a groove 400 formed in the central portion of the exhaust portion by increasing the width of the first region 201. The secondary battery according to this embodiment may include: a first region 201 extending from the central portion of the exhaust portion in a first direction; and a second region 202 extending from the first region 201 in a direction different from the first direction. The second regions 202 may extend from each of one end and the other end of the first region 201 to form a plurality of second regions 202.

[0112] For example, the second region 202 can extend in a second direction perpendicular to the first direction. Figure 7A The third notch 300 may surround the second region 202 by connecting the end of the second region 202, and for example, the second region 202 may be located inside the third notch 300.

[0113] As another example, the second region 202 can extend from the first region 201 in a curved shape. Figure 7B For example, the direction in which the second region 202 extends can be different from the first direction, and the extended second region 202 can increase the rupture area and open space of the exhaust section.

[0114] As another example, the first notch 100 and the first region 201 can be located inside the groove 400 formed in the central portion of the exhaust section. Thus, the stress generated by the expansion of the secondary battery can be concentrated in the groove 400, and the conditions for the exhaust section to rupture and open can be controlled.

[0115] The notch formed in the exhaust section can have various shapes other than those mentioned above. The shape of the notch (including its width, depth, length, position, orientation, etc.) can differ from... Figures 1 to 7C The shape is illustrated in the figure, and the notch can have various shapes as long as the exhaust part is easily broken through the notch.

[0116] The vent can be located within the housing or within a cover plate that covers the upper portion of the housing. For example, the vent can be located between terminals on a terminal section of the cover plate. As another example, the vent can be located on the lower surface of the housing, each of two opposing side surfaces, or one side surface. The shape of the vent (including its size and location) can vary from... Figures 1 to 7C The shape shown in the example is such that the exhaust section can have various shapes, as long as it discharges the gas and heat generated inside the secondary battery through the exhaust section and delays or suppresses the explosion and ignition of the secondary battery.

[0117] By providing an venting section that facilitates the release of gases and heat from within the secondary battery, one or more embodiments can reduce the risk of the spread of thermal runaway (a series of explosions). By forming notches of varying depths within the venting section, the venting section can be sequentially ruptured and opened, and the rupture pressure conditions can be controlled. Through an integral venting section with notches formed therein, one or more embodiments can provide a secondary battery with a simplified manufacturing process and reduced manufacturing costs.

[0118] According to one or more embodiments, when the internal pressure of the secondary battery increases, internal gases and heat can be easily discharged through a vent with a notch formed therein, thereby ensuring the safety and reliability of the secondary battery. Depending on the depth of the notch, sequential rupture can be allowed and rupture conditions can be controlled, ensuring process simplification and reduced manufacturing costs.

[0119] However, the effects obtainable through this disclosure may include other effects besides those described above, and those skilled in the art will clearly understand from the description of this disclosure above that other technical effects not mentioned are possible.

[0120] Although this disclosure has been described herein with reference to limited embodiments and drawings, it is not limited thereto, and it will be apparent to those skilled in the art that various modifications and changes can be made within the scope of the technical concept of this disclosure and the equivalents of the appended claims.

[0121] Exemplary embodiments have been disclosed herein, and although specific terminology has been used, it is used and interpreted in a general and descriptive sense only and is not intended to be limiting. In some instances, as will be apparent to those skilled in the art at the time of filing of this application, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise specifically indicated. Accordingly, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the claims.

Claims

1. A secondary battery, comprising: Electrode assembly; Housing that houses the electrode assembly; as well as A cover plate that covers the open portion of the housing, wherein: One of the housing and the cover plate includes an exhaust portion on its outer surface, the exhaust portion including a notch. The notch includes a first notch and a second notch. The first notch extends from the center portion of the exhaust section in a first direction. The second notch includes: a first region extending from the central portion in the first direction; and a second region extending from the first region in a direction different from the first direction, and The first notch is inside the first region.

2. The secondary battery according to claim 1, wherein the second notch is not as deep as the first notch.

3. The secondary battery according to claim 1, wherein the depth difference between the first notch and the second notch is less than 20% of the thickness of the casing.

4. The secondary battery according to claim 1, wherein the length of the first notch is less than 1 / 3 of the length of the first region.

5. The secondary battery according to claim 1, wherein the depth of the first notch is 70% to 85% of the thickness of the casing.

6. The secondary battery according to claim 1, wherein the depth of the second notch is 50% to 70% of the thickness of the casing.

7. The secondary battery according to any one of claims 1 to 6, wherein: The notch further includes a groove in the central portion of the exhaust section, and The groove extends in the first region to increase the width of the first region.

8. The secondary battery according to any one of claims 1 to 6, wherein: The notch further includes a third notch surrounding the second notch. Each end of the second region is connected by the third notch surrounding the second notch, and The third notch is not as deep as the second notch.

9. The secondary battery according to claim 8, wherein the depth of the third notch is 20% to 50% of the thickness of the casing.

10. The secondary battery according to claim 8, wherein: The width of the third notch is greater than the width of the first notch, and The width of the second notch is greater than the width of the third notch.

11. A secondary battery, comprising: Electrode assembly; Housing that houses the electrode assembly; as well as A cover plate that covers the open portion of the housing, wherein: One of the housing and the cover plate includes an exhaust portion on its outer surface, the exhaust portion including a notch. The notch includes a first notch, a second notch, and a third notch. The first notch extends from the center portion of the exhaust section in a first direction. The second notch includes: a first region extending from the central portion in the first direction; and a second region extending from the first region in a direction different from the first direction. The third notch surrounds the second notch, and Each end of the second region is connected by the third notch surrounding the second notch.

12. The secondary battery according to claim 11, wherein the first notch is inside the first region.

13. The secondary battery according to claim 11, wherein the depth difference between the first notch and the second notch is less than 20% of the thickness of the casing.

14. The secondary battery according to claim 11, wherein the length of the first notch is less than 1 / 3 of the length of the first region.

15. The secondary battery according to claim 11, wherein the depth of the first notch is 70% to 85% of the thickness of the casing.

16. The secondary battery according to claim 11, wherein the depth of the second notch is 50% to 70% of the thickness of the casing.

17. The secondary battery according to claim 11, wherein the depth of the third notch is 20% to 50% of the thickness of the casing.

18. The secondary battery according to any one of claims 11 to 17, wherein: The width of the third notch is greater than the width of the first notch, and The width of the second notch is greater than the width of the third notch.

19. The secondary battery according to any one of claims 11 to 17, wherein: The notch further includes a groove in the central portion of the exhaust section, and The groove extends in the first region to increase the width of the first region.

20. The secondary battery according to any one of claims 11 to 17, wherein: The second notch is not as deep as the first notch, and The third notch is not as deep as the second notch.

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