Battery cell, battery pack, and vehicle including same

Abstract

A battery cell according to the present invention includes: an electrode assembly including electrodes having different polarities and a separator interposed therebetween, the electrodes and the separator being provided to be wound around a central axis of a winding central hole; a cell housing configured to accommodate the electrode assembly and having an opening at one side thereof; and a can lid coupled to one end of the cell housing and the electrode assembly, wherein the can lid includes a vent notch portion formed by notching a radially inner side of an edge of the can lid and formed to have different thicknesses at two or more positions.

Description

Battery cells, battery packs, and automobiles including the same

[0001] The present invention relates to a battery cell, a battery pack, and an automobile including the same, and more specifically, to a battery cell, a battery pack, and an automobile including the same in which venting can be effectively performed when a thermal event occurs.

[0002] This application is a priority claim application for Korean Patent Application No. 10-2024-0143307 filed on October 18, 2024, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference.

[0003] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, research on high-performance secondary batteries capable of repeated charging and discharging is actively underway.

[0004] Currently commercialized rechargeable batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0005] These lithium-ion secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative active materials, respectively. Additionally, the lithium-ion secondary battery comprises an electrode assembly in which a positive plate and a negative plate, each coated with the positive and negative active materials, are arranged with a separator in between, and an outer casing that seals and encloses the electrode assembly together with an electrolyte.

[0006] Meanwhile, lithium-ion rechargeable batteries can be classified according to the shape of the battery case into pouch-type rechargeable batteries, in which the electrode assembly is embedded in an aluminum laminate sheet pouch, and can-type rechargeable batteries, in which the electrode assembly is embedded in a metal can. Furthermore, can-type rechargeable batteries can be further classified into cylindrical batteries and prismatic batteries depending on the shape of the metal can. These lithium-ion rechargeable batteries are utilized as battery modules or battery packs, in which multiple battery cells are assembled into a dense structure by overlapping or stacking them to provide high voltage and high current, and then electrically connected.

[0007] FIG. 1 is a drawing showing a can lid of a conventional battery cell. Referring to FIG. 1, the conventional battery cell may include an electrode assembly and a cell housing that accommodates it, and a can lid (300') that is coupled to an opening of the cell housing. In the can lid (300') of the conventional battery cell, the electrode coupling portion (310') that is welded to the electrode assembly is formed in a single flat shape that is entirely flat and without curvature along the periphery of the flat portion surrounding the injection port.

[0008] In such conventional battery cell can lids (300'), the flatness with respect to the electrode assembly may be unstable or inconsistent, so the welding with respect to the electrode assembly may be formed as over-welded or under-welded, resulting in poor welding quality, and the dimensions such as welding flatness with respect to the electrode assembly, welding length, and injection port diameter were not matched.

[0009] In addition, the can lid (300') of a conventional battery cell is provided with a vent notch portion that is notched so that it can be broken and opened when high temperature and high pressure are formed in the battery cell due to a thermal event. This vent notch portion of the conventional battery cell could be provided on the radially outer side of the electrode coupling portion (310'). Furthermore, although the vent notch portion of the conventional battery cell is designed to have a uniform thickness throughout the entire section during design, thickness variations may occur depending on the location due to various factors such as punch wear and mold part tolerances during the actual manufacturing process, and as a result, a dispersion of vent pressure (e.g., the magnitude of the internal pressure of the battery cell at which the vent notch portion begins to break) may occur depending on the location.

[0010] As a result, conventional battery cells could not effectively vent when a thermal event occurred.

[0011] In addition, the can lid (300') of a conventional battery cell could be cumbersome to manage. Specifically, since the thickness variation and vent pressure dispersion by location as described above could exist throughout the entire vent notch portion of the conventional can lid (300'), it was necessary to manage the thickness variation or vent pressure dispersion of the vent notch portion throughout the entire vent notch portion. This could be a factor that makes the management of the can lid (300') cumbersome.

[0012] The present invention was conceived in consideration of the aforementioned problems and has one objective of providing a battery cell, a battery pack, and an automobile including the same, which can effectively perform venting when a thermal event occurs.

[0013] In addition, another purpose is to provide a battery cell, a battery pack, and a vehicle including the same, which can facilitate the management of the can lid.

[0014] The technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art from the description of the invention below.

[0015] A battery cell according to the present invention comprises: an electrode assembly provided by being wound around the central axis of a winding center hole with a separator interposed between electrodes of different polarities; a cell housing that accommodates the electrode assembly and has an opening on one side; and a can lid coupled to one end of the cell housing and the electrode assembly, wherein the can lid is formed by notching on the radially inner side of the edge and has a vent notch portion formed such that the thicknesses at at least two locations are formed differently from each other.

[0016] The above-mentioned bent notch portion may extend along the circumferential direction for at least a portion.

[0017] The cross-section of the above-mentioned bent notch viewed from the circumferential direction can be formed in a V-shape or a U-shape.

[0018] The thickness of the vent notch portion in the section corresponding to the part of the can lid where stress is concentrated due to the internal pressure of the battery cell may be formed to be thinner than the thickness of the vent notch portion in the remaining other sections.

[0019] The can lid comprises at least one electrode coupling portion that is positioned relatively closer to the electrode assembly than to a surrounding portion and is coupled to the electrode assembly; and at least one spacing portion that is spaced apart from the electrode assembly, wherein the vent notch portion has a first point located in a section corresponding to the electrode coupling portion, a second point located in a section corresponding to the spacing portion, and a third point located between the first point and the second point, and the thickness of the vent notch portion at the third point may be formed to be thinner than the thickness of the vent notch portion at the first point and the thickness of the vent notch portion at the second point.

[0020] The thickness of the vent notch portion at the first point and the thickness of the vent notch portion at the second point can be formed to be the same as each other.

[0021] The above-mentioned vent notch portion may be disposed radially on the outer side of the electrode coupling portion.

[0022] The can lid is configured to be coupled to one end of the cell housing and further comprises an edge portion formed at the edge of the can lid, and the bent notch portion may be provided radially inward from the edge portion.

[0023] The above-mentioned bent notch portion may be formed such that the thickness of each of at least two locations forms a discontinuous thickness change between the two locations.

[0024] The above-mentioned bent notch portion may be formed such that the thickness of each of at least two locations forms a gradual thickness change between the two locations.

[0025] The above-mentioned vent notch may be formed only on one side of the can lid, either the upper surface far from the electrode assembly or the lower surface close to the electrode assembly.

[0026] The above-mentioned vent notch may be formed on both the upper surface far from the electrode assembly and the lower surface close to the electrode assembly of the can lid.

[0027] The above-mentioned vent notch may be formed on only one of the upper surface far from the electrode assembly and the lower surface close to the electrode assembly in a certain section, and may be formed on both the upper surface and the lower surface of the can lid in the remaining section.

[0028] The above-mentioned bent notch portion can be formed by extending in a continuous form.

[0029] The above-mentioned bent notch portion may be formed by extending in a discontinuous shape.

[0030] A battery pack according to the present invention is characterized by including at least one battery cell according to the present invention.

[0031] An automobile according to the present invention is characterized by including at least one battery pack according to the present invention.

[0032] According to the present invention, a battery cell, a battery pack, and an automobile including the same can be provided, wherein venting can be effectively performed when a thermal event occurs.

[0033] In addition, a battery cell, a battery pack, and a vehicle including the same can be provided, which can facilitate the management of the can lid.

[0034] In addition, a battery cell, a battery pack, and an automobile including the same can be provided, in which the processing of the vent notch portion can be facilitated.

[0035] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the attached drawings.

[0036] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0037] Figure 1 is a drawing showing a can lid of a conventional battery cell.

[0038] FIG. 2 is a perspective view showing the overall appearance of a battery cell according to one embodiment of the present invention.

[0039] FIG. 3 is a side cross-sectional view showing a cross- section of a battery cell according to one embodiment of the present invention.

[0040] FIG. 4 is a plan view showing a can lid according to one embodiment of the present invention.

[0041] FIG. 5 is a side cross-sectional view showing a cross-section of a bent notch portion viewed from the circumferential direction according to one embodiment of the present invention.

[0042] FIG. 6 is a schematic diagram showing a cross-sectional view of a bent notch portion viewed from the radial direction according to another embodiment of the present invention.

[0043] FIG. 7 is a schematic diagram showing a cross-sectional view of a bent notch portion viewed from the radial direction according to another embodiment of the present invention.

[0044] FIG. 8 is a side cross-sectional view showing the appearance of a bent notch portion formed on the upper or lower surface of a can lid according to one embodiment of the present invention.

[0045] FIG. 9 is a side cross-sectional view showing a bent notch portion formed on both the upper and lower surfaces of a can lid according to one embodiment of the present invention.

[0046] FIG. 10 is a side cross-sectional view showing a part of the BB' section of FIG. 4.

[0047] FIG. 11 is a side cross-sectional view showing another part of the BB' section of FIG. 4.

[0048] Figure 12 is a table showing the inner diameter of the injection port, etc., according to the winding center hole size of the electrode assembly.

[0049] Figure 13 is a drawing showing a conventional separable can lid.

[0050] FIG. 14 is a table showing the results of each vent pressure measurement for a battery cell according to an embodiment and a battery cell according to a comparative example.

[0051] Figure 15 is a photograph showing a comparison of the discharge appearance of the electrode assembly after venting of the battery cell according to the embodiment and the battery cell according to the comparative example.

[0052] FIG. 16 is a drawing showing a battery pack according to one embodiment of the present invention.

[0053] FIG. 17 is a drawing showing an automobile according to one embodiment of the present invention.

[0054] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0055] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0056] The statement that two subjects of comparison are identical means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a domain may mean that it is uniform from an average perspective.

[0057] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0058] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0059] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0060] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0061] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0062] Meanwhile, contents common to parts described in any one embodiment of the present invention may also be applied to other embodiments. For example, contents common to parts described in the first embodiment of the second embodiment may be replaced by the description of the first embodiment described above, and such common contents may also be applied to the second embodiment. Furthermore, contents described in the second embodiment that are applicable to the first embodiment may also be applied to the first embodiment. The same applies to other embodiments.

[0063] In this specification, unless otherwise specified, the X-axis and Y-axis directions may be left-right and front-back directions, or front-back and left-right directions, respectively, and the Z-axis direction orthogonal to the XY plane may be up-down direction (vertical direction).

[0064] In this specification, for convenience of explanation, the direction following the longitudinal direction of the central axis of the winding center hole of the electrode assembly is referred to as the axial direction. The axial direction may coincide with the Z-axis direction. Furthermore, the direction surrounding the central axis of the winding center hole is referred to as the circumferential direction. Furthermore, the direction approaching or moving away from the central axis of the winding center hole is referred to as the radial direction.

[0065]

[0066] FIG. 2 is a perspective view showing the overall appearance of a battery cell according to one embodiment of the present invention, and FIG. 3 is a side cross-sectional view showing a cross- section of a battery cell according to one embodiment of the present invention.

[0067] Referring to FIGS. 2 and FIGS. 3, a battery cell (10) according to one embodiment of the present invention may include an electrode assembly (100), a cell housing (200), and a can lid (300).

[0068] The battery cell (10) may be a secondary battery configured to be rechargeable. For example, the battery cell (10) may be a cylindrical battery cell (10).

[0069] The electrode assembly (100) may comprise a first electrode and a second electrode and a separator interposed between them. The first electrode may have a first polarity, and the second electrode may have a second polarity opposite to the first polarity. For example, the first polarity may be positive and the second polarity may be negative. In the following description, the first electrode may be referred to as the positive electrode and the second electrode as the negative electrode. However, in all embodiments described herein, it should be understood that the described polarities of the first electrode and the second electrode may be changed or reversed.

[0070] The electrode assembly (100) may be configured such that a first electrode and a second electrode and a separator interposed between them are laminated to form a laminate. The laminate of the first electrode, the second electrode, and the separator of the electrode assembly (100) may be wound around the central axis (A) of the winding center hole (core) (C) and provided in a jelly-roll form. The electrodes (first electrode and second electrode) may have a blank portion (112) that does not contain active material. The blank portion (112) may be located along the long side end of each electrode before winding, and after winding, the blank portion (112) may be located at the axial end of the electrode assembly (100). The blank portion (112) may have a plurality of notched foil tabs.

[0071] For example, the first electrode is an anode plate, and an anode active material is coated on one or both sides of the anode plate, and a first blank portion (112a) on which the anode active material is not coated may be formed at the end of the anode plate. The first blank portion (112a) may be formed on one side of the anode plate that extends parallel to the winding direction of the laminate. The first blank portion (112a) may be exposed to the outside by protruding axially beyond the edge of the separator while forming a plurality of winding turns around the central axis (A) of the winding center hole (C), and may be used as an electrode tab itself.

[0072] The second electrode is a negative plate, and a negative active material is coated on one or both sides of the negative plate, and a second blank portion (112b) in which the negative active material is not coated may be formed at the end of the negative plate. The second blank portion (112b) may be formed on one side of the negative plate that extends parallel to the winding direction of the laminate. The second blank portion (112b) may be exposed to the outside by protruding axially beyond the edge of the separator while forming a plurality of winding turns around the central axis (A) of the winding center hole (C), and may be used as an electrode tab itself.

[0073] The edge of the separator where the second blank portion (112b) protrudes axially may be the edge opposite in the axial direction to the edge of the separator where the first blank portion (112a) protrudes axially. Accordingly, the electrode tabs of opposite polarity may be located at opposite ends in the axial direction of the electrode assembly (100) wound thereon. For example, the first blank portion (112a) may be located at the -Z direction side end of the electrode assembly (100), and the second blank portion (112b) may be located at the +Z direction side end of the electrode assembly (100).

[0074] That is, the positive plate and the negative plate may each include an uncoated portion at the long end of the winding direction in which the active material is not coated. Additionally, the first uncoated portion (112a) and the second uncoated portion (112b) may be configured to protrude in opposite directions in the axial direction.

[0075] The first blank portion (112a) and the second blank portion (112b) may each include, for example, a plurality of foil tabs in the form of flags arranged in the winding direction. The plurality of foil tabs may be formed by notching or slitting the blank portion. In the jelly-roll type electrode assembly (100), the foil tabs may be flattened by bending them radially. The foil tabs may be bent radially inward or outward. The foil tabs may be bent one by one during the process of winding the laminate to form the jelly-roll type electrode assembly (100). Alternatively, the foil tabs may be bent all at once after winding the laminate to form the jelly-roll type electrode assembly (100). The foil tabs of the first blank section (112a) and the foil tabs of the second blank section (112b), which are folded and overlapped in the radial direction in this way, can each form a plane that is substantially perpendicular to the axial direction at both axial ends of the electrode assembly (100).

[0076] An electrode assembly (100) can be accommodated in the cell housing (200). The electrode assembly (100) can be accommodated inside the cell housing (200). The cell housing (200) can be configured in a cylindrical shape, for example. If the cell housing (200) is configured in a cylindrical shape, the battery cell (10) can be configured as a cylindrical battery cell (10).

[0077] An opening (210) may be formed on one side of the cell housing (200). For example, an opening (210) may be formed on the +Z direction side of the cell housing (200). An electrode assembly (100) may be inserted through the opening (210) formed on one side of the cell housing (200) and accommodated in the cell housing (200).

[0078] The can lid (300) can be coupled to one end of the cell housing (200) and the electrode assembly (100). Specifically, the can lid (300) can be coupled to one end of the cell housing (200) in which an opening (210) is formed.

[0079] The can lid (300) may be configured to cover the opening (210). The can lid (300) may be configured to seal the opening (210) of the cell housing (200). The can lid (300) may be press-fitted to one end of the cell housing (200). The can lid (300) may be welded to one end of the cell housing (200).

[0080] The can lid (300) can be electrically connected to the cell housing (200).

[0081] The can lid (300) can be coupled to the electrode assembly (100). The can lid (300) can be electrically connected to the electrode assembly (100). The can lid (300) can be directly coupled by contacting the electrode assembly (100). The can lid (300) can be electrically connected to the second electrode. The can lid (300) can be coupled to the second non-removable portion (112b). The can lid (300) can have a second polarity.

[0082] The can lid (300) can be electrically connected to the cell housing (200) and the electrode assembly (100), respectively. In this case, the cell housing (200) may have a second polarity.

[0083]

[0084]

[0085] Meanwhile, the can lid (300) according to the present invention is coupled to the cell housing (200) to cover the opening (210) of the cell housing (200), and at the same time can be directly coupled to the electrode assembly (100), so, for example, a configuration such as a negative electrode current collector plate may not be separately provided. That is, the can lid (300) according to the present invention can be provided as a so-called integrated can lid (300) that can perform the function of a current collector plate.

[0086] Meanwhile, a closed portion (220) may be provided on the other side of the cell housing (200). For example, a closed portion (220) may be provided on the -Z direction side of the cell housing (200). In the cell housing (200), the closed portion (220) may be located on the opposite side of the open portion (210).

[0087] Meanwhile, the battery cell (10) according to the present invention may further include a terminal (400). The terminal (400) may be disposed in the closed portion (220). The terminal (400) may be electrically connected to the first electrode. The terminal (400) may have a first polarity. The terminal (400) may be configured in the form of a rivet that is disposed through the closed portion (220).

[0088] Meanwhile, the cell housing (200) may include a conductive metal. The cell housing (200), excluding the terminal (400), is electrically connected to the second electrode and may have a second polarity. The closure portion (220) may have a second polarity. That is, in the battery cell (10) according to the present invention, both the first polarity and the second polarity may be formed on the closure portion (220) side. An insulating gasket (500) that electrically insulates them may be disposed between the closure portion (220) and the terminal (400).

[0089] Meanwhile, the battery cell (10) according to the present invention may include a current collector plate (600). The current collector plate may have a first polarity. The current collector plate (600) may be composed of, for example, a positive current collector plate. The current collector plate (600) may be electrically connected to a first non-circulating portion (112a). The current collector plate (600) may be disposed between the electrode assembly (100) and the closing portion (220) inside the cell housing (200). An insulator (700) may be disposed between the current collector plate (600) and the closing portion (220). The insulator (700) may be configured to electrically insulate the current collector plate (600) and the closing portion (220).

[0090] Meanwhile, the cell housing (200) may be configured to extend along the axial direction parallel to the axial direction. That is, the cell housing (200) may be configured to be indented radially inward or not bent. For example, the cell housing (200) may not have a beading portion indented radially inward and / or a crimping portion bent radially inward. When the cell housing is configured in this way, the internal space of the battery cell is increased, and the space efficiency and energy density of the battery cell can be improved.

[0091]

[0092] FIG. 4 is a plan view showing a can lid according to one embodiment of the present invention, and FIG. 5 is a side cross-sectional view showing a cross-sectional view of a bent notch portion according to one embodiment of the present invention viewed from the circumferential direction.

[0093] Referring to FIGS. 4 and FIGS. 5, in a battery cell (10) according to one embodiment of the present invention, the can lid (300) may have a vent notch portion (380).

[0094] The bent notch portion (380) can be formed by notching the inner side of the edge of the can lid (300).

[0095] The vent notch portion (380) may be configured to be broken by the internal pressure of the battery cell (10). The vent notch portion (380) may be a part configured to be broken when the internal pressure of the battery cell (10) is formed to be greater than a preset size. Specifically, when a thermal event occurs in the battery cell (10), the internal pressure of the high-temperature venting gas is formed, and when the internal pressure is formed to be greater than a preset size, the vent notch portion (380) may be broken. When the vent notch portion (380) is broken, the venting gas can be smoothly discharged from the battery cell (10) to the outside. Therefore, when the can lid (300) is equipped with the vent notch portion (380), the venting gas can be easily and smoothly discharged from the battery cell (10), thereby ensuring high venting performance of the battery cell (10).

[0096] Meanwhile, the magnitude of the internal pressure of the battery cell (10) at which the vent notch portion (380) begins to break can be defined as the vent pressure. And, the vent pressure at which the vent notch portion (380) actually begins to break can be defined as the actual vent pressure. Furthermore, the vent notch portion (380) can be designed to be pre-set so that it breaks at a specific vent pressure, and said specific vent pressure can be defined as the pre-set vent pressure.

[0097] The bent notch portion (380) may be formed with different thicknesses at at least two locations. Specifically, the thickness of the bent notch portion (380) at one location may be formed thinner than the thickness of the bent notch portion (380) at another location.

[0098] In a battery cell (10) according to one embodiment of the present invention, the vent notch portion (380) may be formed as described above. When high temperature and high pressure are formed inside the battery cell (10) due to a thermal event, the portion of the vent notch portion (380) corresponding to one location formed relatively thin may begin to break at a lower vent pressure than the portion of the vent notch portion (380) corresponding to another location formed relatively thick. As a result, the venting of the battery cell (10) can be effectively achieved. Specifically, by forming different vent pressures at different locations in the vent notch portion (380), the discharge of venting gas proceeds first in a specific part of the vent notch portion (380), and the discharge of venting gas proceeds stepwise or sequentially in a part different from the specific part, thereby enabling the venting of the battery cell (10) to be effectively achieved. In addition, the venting gas can be discharged in a balanced manner according to the location of the vent notch (380), so that additional damage to other parts of the battery cell (10) excluding the can lid (300) or the risk of explosion of the battery cell (10) is prevented, and the venting of the battery cell (10) can be achieved.

[0099] In addition, in the battery cell (10) according to one embodiment of the present invention, as described above, since fracture can be induced more easily in a specific part of the vent notch (380), it is sufficient to intensively manage the thickness variation or vent pressure dispersion of the vent notch (380) only in the specific part where fracture is easily induced, thus making it easier to manage the can lid (300).

[0100]

[0101] The bent notch portion (380) may extend along the circumferential direction for at least a portion. Specifically, the bent notch portion (380) may extend along the circumferential direction to form part or all of a circle radially inward from the edge of the can lid (300).

[0102] In this case, when venting the battery cell (10), the vent notch (380) can be induced to break in a roughly circular shape, so that the electrode assembly (100) provided, which is wound around the central axis (A) of the winding center hole (C), can be discharged more smoothly from the battery cell (10).

[0103]

[0104] The cross-section of the vent notch portion (380) may be formed in a V-shape or a U-shape. Specifically, the cross-section of the vent notch portion (380) viewed from the circumferential direction may be formed in a V-shape as shown in FIG. 5. The cross-section of the vent notch portion (380) viewed from the circumferential direction may be formed in a U-shape, unlike as shown in FIG. 5.

[0105] If the cross-section of the vent notch (380) is formed in a V-shape, there may be an advantage that the fracture induction position can be precisely controlled, and if the cross-section of the vent notch (380) is formed in a U-shape, there may be an advantage that the venting gas discharge characteristics can be formed relatively smoothly. The cross-section of the vent notch (380) is not limited to a V-shape or a U-shape and may be configured in various other shapes.

[0106]

[0107] The bent notch portion (380) can be formed with a relatively thinner thickness in the section corresponding to the stress concentration portion (SC) of the can lid (300).

[0108] Specifically, the thickness of the vent notch portion (380) in the section corresponding to the portion of the can lid (300) where stress is concentrated due to the internal pressure of the venting gas generated inside the battery cell (10) (stress concentration portion (SC)) can be formed thinner than the thickness of the vent notch portion (380) in the remaining other sections. For example, the thickness of the vent notch portion (380) in the section belonging to the stress concentration portion (SC) shown in FIG. 4 can be formed thinner than the thickness of the vent notch portion (380) in other sections not belonging to the stress concentration portion (SC).

[0109] The stress concentration portion (SC) may be formed, for example, in a portion adjacent to the third portion (Po3) or third point (P3) described later.

[0110] Accordingly, when a thermal event occurs in the battery cell (10), the portion corresponding to the stress concentration portion (SC) in the vent notch portion (380) may be formed to be more vulnerable to fracture than the rest of the other portions. Therefore, when the vent notch portion (380) is formed as described above, the portion that is already formed to be relatively vulnerable to fracture may be formed to be even more vulnerable to fracture. As a result, the venting of the battery cell (10) can be performed more effectively, and the management of the can lid (300) can be made easier.

[0111]

[0112] In particular, referring to FIG. 4, the can lid (300) may be provided with an electrode coupling portion (310) and a separation portion (360).

[0113] The electrode coupling portion (310) can be coupled to the electrode assembly (100). For example, the electrode coupling portion (310) can be coupled to the second electrode. The electrode coupling portion (310) can be coupled to the electrode assembly (100) by welding. For example, the electrode coupling portion (310) can be coupled to the second non-coupling portion (112b) by welding.

[0114] The bottom surface of the electrode coupling portion (310) (the surface facing the electrode assembly (100)) can be coupled face-to-face with the electrode assembly (100). The bottom surface of the electrode coupling portion (310) can be coupled with the second non-reinforced portion (112b).

[0115] The electrode coupling portion (310) may be positioned at a location relatively closer to the electrode assembly (100) than the surrounding portion. Here, the surrounding portion can be understood as a part of the can lid (300) located around the electrode coupling portion (310), excluding the electrode coupling portion (310). The electrode coupling portion (310) may be positioned further down or further in the -Z direction than the surrounding portion so that it may be positioned at a location relatively closer to the electrode assembly (100) than the surrounding portion.

[0116] The electrode coupling portion (310) may be formed by being recessed toward the electrode assembly (100) along the axial direction, for example. For example, the electrode coupling portion (310) may be formed by being recessed toward the -Z direction.

[0117] The electrode coupling portion (310) may be provided in multiple numbers. For example, the electrode coupling portion (310) may be provided in three numbers. The multiple electrode coupling portions (310) may be spaced apart from each other. For example, the multiple electrode coupling portions (310) may be spaced apart from each other along the circumferential direction.

[0118] The separation portion (360) may be configured to partition any two adjacent electrode coupling portions (310). For example, the separation portion (360) may be positioned between any two electrode coupling portions (310) adjacent in the circumferential direction to partition the two separated electrode coupling portions (310).

[0119] The separation portion (360) may be separated from the electrode assembly (100). For example, the bottom surface of the separation portion (360) may be separated axially from the top surface of the electrode assembly (100). The separation portion (360) may be separated from the foil tab of the electrode assembly (100). For example, the separation portion (360) may be separated axially from the foil tab provided in the second blank portion (112b).

[0120] The separation portion (360) may be positioned at a location relatively farther from the electrode assembly (100) than the electrode coupling portion (310). For example, the separation portion (360) may be positioned further up or in the +Z direction from the electrode assembly (100) than the electrode coupling portion (310).

[0121] The separation portion (360) may be provided as at least one. For example, the separation portion (360) may be provided as only one, or as a plurality.

[0122] For example, a spacing portion (360) may be disposed between two adjacent electrode coupling portions (310). For example, an electrode coupling portion (310) may be disposed between two adjacent spacing portions (360).

[0123] The separation portion (360) may be spaced apart from the electrode assembly (100) to form an empty space between them. Various gases that may be generated inside the battery cell (10) may be contained in the empty space. Additionally, a path for the movement of the electrolyte may be secured through the empty space.

[0124] When the battery cell (10) is configured as described above, electrical connectivity between the can lid (300) and the electrode assembly (100) can be ensured by the electrode coupling portion (310). Additionally, there is an advantage that a gap can be reliably formed between the can lid (300) and the electrode assembly (100) by the spacing portion (360).

[0125]

[0126] In particular, referring to FIG. 4, a first point (P1), a second point (P2), and a third point (P3) may be located in the bent notch portion (380).

[0127] The first point (P1) can be understood as a location in a section corresponding to the electrode coupling portion (310) of the vent notch portion (380). Here, the section corresponding to the electrode coupling portion (310) of the vent notch portion (380) may be, for example, a section of the vent notch portion (380) that overlaps with the electrode coupling portion (310) when viewed from a radial direction, and may be referred to as the first section (S1). The first point (P1) can be understood as a location located approximately in the center of the first section (S1), for example, based on the circumferential direction.

[0128] The second point (P2) can be understood as a location in a section corresponding to the gap (360) of the vent notch section (380). Here, the section corresponding to the gap (360) of the vent notch section (380) may be, for example, a section of the vent notch section (380) that overlaps with the gap (360) when viewed from the radial direction, and may be referred to as the second section (S2). The second point (P2) can be understood as a location located approximately in the center of the second section (S2), for example, based on the circumferential direction.

[0129] The third point (P3) can be understood as any location situated between the first point (P1) and the second point (P2). For example, the third point (P3) may be a location existing at the boundary between the first section (S1) and the second section (S2), or in a section adjacent to said boundary.

[0130] A first part (Po1), a second part (Po2), and a third part (Po3) may be formed at the edge of the electrode coupling portion (310). The first part (Po1) is a portion formed on the side of the bent notch portion (380) or on the radially outer side at the edge of the electrode coupling portion (310), and may be formed approximately parallel to the bent notch portion (380). The first part (Po1) may, for example, extend along the circumferential direction with a predetermined constant curvature from the radially outer edge of the electrode coupling portion (310).

[0131] The second part (Po2) may be a portion formed at the boundary between the edge of the electrode coupling portion (310) and the spaced-out portion (360). The second part (Po2) may be formed by extending toward the first part (Po1). The second part (Po2) may be extended in a straight line, for example.

[0132] The third part (Po3) may be a part formed between the first part (Po1) and the second part (Po2). The third part (Po3) may connect the first part (Po1) and the second part (Po2). The edge of the electrode coupling part (310) may be formed in a bent shape at the third part (Po3). The third part (Po3) may be configured in a curved shape having curvature, and in this case, among the first part (Po1), the second part (Po2) and the third part (Po3), the position where the curvature is formed least may be formed at the third part (Po3).

[0133] The third point (P3) may exist on the section of the bent notch (380) that overlaps with the third part (Po3) when viewed radially from the center of the can lid (300), for example.

[0134] FIG. 5 (a) shows a cross-section (a cross-section viewed from the circumferential direction) of the vent notch portion (380) at the first point (P1) and the second point (P2), and FIG. 5 (b) shows a cross-section (a cross-section viewed from the circumferential direction) of the vent notch portion (380) at the third point (P3). Referring to FIG. 5 (a) and FIG. 5 (b), the thickness of the vent notch portion (380) at the third point (P3) can be formed to be thinner than the thickness of the vent notch portion (380) at the first point (P1) and the thickness at the second point (P2).

[0135] In the vent notch portion (380), the previously described stress concentration portion (SC) may be formed in the portion adjacent to the third portion (Po3) or the third point (P3). Accordingly, when the thickness at the third point (P3) of the vent notch portion (380) is formed as described above, the venting of the battery cell (10) can be performed more effectively, and the management of the can lid (300) can be made easier.

[0136]

[0137] Referring to FIG. 5 (a), the thickness of the vent notch portion (380) at the first point (P1) and the thickness of the vent notch portion (380) at the second point (P2) can be formed to be the same. Specifically, the thickness of the vent notch portion (380) at the first point (P1) and the thickness of the vent notch portion (380) at the second point (P2) can both be formed as in FIG. 5 (a).

[0138] In this case, when notching the vent notch portion (380), the thickness at the first point (P1) and the second point (P2) is made the same, and only the thickness at the third point (P3) is made thinner than these, so the processing of the vent notch portion (380) can be made easier.

[0139]

[0140] Meanwhile, FIG. 5 (c) shows a vent notch portion (380) with a thinner thickness than the embodiment of FIG. 5 (a). Either the thickness of the vent notch portion (380) at the first point (P1) or the thickness of the vent notch portion (380) at the second point (P2) may correspond to FIG. 5 (c), and the other may correspond to FIG. 5 (a). That is, the thickness of the vent notch portion (380) at the first point (P1) and the thickness of the vent notch portion (380) at the second point (P2) may be formed differently from each other.

[0141]

[0142] The vent notch portion (380) can be positioned radially on the outer side of the electrode coupling portion (310).

[0143] In this case, interference between the vent notch portion (380) and the electrode coupling portion (310) can be prevented. Additionally, since the electrode coupling portion (310) is a part that can be welded, it may not be suitable for notching the vent notch portion (380). Furthermore, if the vent notch portion (380) is configured as described above, the area of ​​the radial inner region of the vent notch portion (380) can be secured widely, so that the fracture of the vent notch portion (380) can be easily induced.

[0144]

[0145] In particular, as illustrated in FIG. 4, the can lid (300) may further be provided with an edge portion (370). The edge portion (370) may be formed on the edge of the can lid (300) so as to be coupled to the cell housing (200). The edge portion (370) may be coupled by a press fit to an opening (210) formed on one side of the cell housing (200). The edge portion (370) may be coupled to the cell housing (200) by welding after being press-fitted to one side of the cell housing (200). The cross-section of the edge portion (370) may be approximately U-shaped. The end of the edge portion (370) close to the electrode assembly (100) may be spaced apart from the electrode assembly (100).

[0146] The bent notch portion (380) may be provided on the radially inner side of the edge portion (370). The bent notch portion (380) may be positioned radially between the electrode coupling portion (310) and the edge portion (370).

[0147] The edge portion (370) may be extended along the circumferential direction. The bent notch portion (380) may be extended parallel to the edge portion (370).

[0148] In this way, when the can lid (300) is provided with an edge portion (370), the bonding between the can lid (300) and the cell housing (200) can be strengthened. When the vent notch portion (380) is provided on the inner side of the edge portion (370), the edge portion (370) and the vent notch portion (380) do not interfere with each other, so the venting of the battery cell (10) can be formed smoothly. In addition, since the edge portion (370) can be a welding target and is a part that can be deformed by a press fit, it may not be suitable for notching processing of the vent notch portion (380).

[0149]

[0150] Meanwhile, the electrode coupling portion (310) may be positioned between the flat portion (320) and the edge portion (370) described later. That is, the flat portion (320), the electrode coupling portion (310), and the edge portion (370) described later may be positioned sequentially along the radial direction.

[0151]

[0152] FIG. 6 is a schematic diagram showing a cross-sectional view of a bent notch portion viewed from the radial direction according to another embodiment of the present invention.

[0153] For reference, FIG. 6 is a schematic drawing showing a portion of the bent notch section (380) including the first point (P1), the second point (P2), and the third point (P3) unfolded so that the circumferential direction (CD) is the horizontal direction for convenience of explanation.

[0154] Referring to FIG. 6, the bent notch portion (380) according to another embodiment of the present invention may be formed differently such that the thickness of each of at least two positions forms a discontinuous thickness change between the two positions. That is, the bent notch portion (380) may have a stepped portion formed between at least two positions.

[0155] For example, the thickness of the vent notch portion (380) at the third point (P3) may be formed to be thinner than the thickness of the vent notch portion (380) at the first point (P1) and / or the thickness of the vent notch portion (380) at the second point (P2), and there may be a stepped portion formed between the first point (P1) and the third point (P3) and / or between the second point (P2) and the third point (P3).

[0156] When the vent notch portion (380) is formed as described above, stress may be concentrated in the portion formed with a step difference between at least two positions of the vent notch portion (380). Also, the processing of the vent notch portion (380) may be facilitated.

[0157]

[0158] FIG. 7 is a schematic diagram showing a cross-sectional view of a bent notch portion viewed from the radial direction according to another embodiment of the present invention.

[0159] For reference, FIG. 7 is a schematic drawing showing a portion of the bent notch section (380) including the first point (P1), the second point (P2), and the third point (P3) unfolded so that the circumferential direction (CD) is the horizontal direction for convenience of explanation.

[0160] Referring to FIG. 7, the bent notch portion (380) according to another embodiment of the present invention may be formed differently such that the thickness of each of at least two positions forms a gradual change in thickness between the two positions.

[0161] For example, the thickness of the vent notch portion (380) at the third point (P3) may be formed to be thinner than the thickness of the vent notch portion (380) at the first point (P1) and / or the thickness of the vent notch portion (380) at the second point (P2), and there may be a portion formed such that the thickness changes continuously between the first point (P1) and the third point (P3) and / or between the second point (P2) and the third point (P3).

[0162] When the bent notch portion (380) is formed as described above, the thickness of the bent notch portion (380) can be formed to vary finely between the portion where stress is relatively concentrated (e.g., the portion adjacent to the third point (P3)) and the portion where stress is relatively less concentrated (e.g., the portion adjacent to the first point (P1) and the portion adjacent to the second point (P2).

[0163]

[0164] FIG. 8 is a side cross-sectional view showing the appearance of a bent notch portion formed on the upper or lower surface of a can lid according to one embodiment of the present invention.

[0165] FIG. 8 (a) shows a side cross-section viewed from the circumferential direction of a vent notch (380) formed on the upper surface of a can lid (300), and FIG. 8 (b) shows a side cross-section viewed from the circumferential direction of a vent notch (380) formed on the lower surface of a can lid (300).

[0166] According to one embodiment of the present invention, the vent notch portion (380) may be formed by notching only one of the upper or lower surfaces of the can lid (300). That is, the vent notch portion (380) may be notched only on the upper surface of the can lid (300) (see FIG. 8 (a)) or notched only on the lower surface of the can lid (300) (see FIG. 8 (b)). Here, the upper surface of the can lid (300) may be the surface of the can lid (300) that is far from the electrode assembly (100). Here, the lower surface of the can lid (300) may be the surface of the can lid (300) that is close to the electrode assembly (100).

[0167] When the vent notch portion (380) is formed by processing as described above, only one side of the can lid (300) needs to be processed, so the processing of the vent notch portion (380) can be made easier.

[0168]

[0169] Meanwhile, the vent notch portion (380) according to one embodiment of the present invention may be formed such that only one of the upper or lower surfaces of the can lid (300) is notched in a portion of the section, and the other of the upper or lower surfaces is notched in the remaining section.

[0170]

[0171] FIG. 9 is a side cross-sectional view showing a bent notch portion formed on both the upper and lower surfaces of a can lid according to one embodiment of the present invention.

[0172] FIG. 9 shows a side cross-section of the bent notch portion (380) formed on the upper and lower surfaces of the can lid (300) viewed from the circumferential direction.

[0173] According to one embodiment of the present invention, the vent notch portion (380) can be formed by notching both the upper and lower surfaces of the can lid (300), as shown in FIG. 9.

[0174] When the vent notch portion (380) is formed by processing as described above, both sides of the can lid (300) can be processed, so a change in the thickness of the vent notch portion (380) can be provided more clearly.

[0175]

[0176] According to one embodiment of the present invention, the vent notch portion (380) may be formed such that only one of the upper or lower surfaces of the can lid (300) is notched in a certain section, and both the upper and lower surfaces of the can lid (300) are notched in the remaining section. That is, the vent notch portion (380) may be provided by notching in a combined form of FIG. 8 and FIG. 9.

[0177] For example, the vent notch portion (380) may be notched on both the upper and lower surfaces of the can lid (300) in the area where stress is relatively concentrated, and may be notched on only one of the upper or lower surfaces of the can lid (300) in the area where stress is relatively less concentrated.

[0178] When the vent notch portion (380) is formed by processing as described above, the thickness difference between the positions of the vent notch portion (380) can be formed more clearly.

[0179]

[0180] Referring again to FIG. 4, the vent notch portion (380) can be formed in a continuous shape. In this case, under the same preset vent pressure conditions, the notching depth of the vent notch portion (380) can be formed relatively thinly, which may be advantageous in terms of processing the vent notch portion (380).

[0181]

[0182] The vent notch portion (380) may be formed in a discontinuous shape, unlike as shown in FIG. 4. For example, the vent notch portion (380) may be formed in only some sections along the circumferential direction and not formed in other sections.

[0183] When the vent notch portion (380) is configured in this manner, the pre-set vent pressure is formed weakly in the portion where the vent notch portion (380) is formed, and the pre-set vent pressure is formed strongly in the portion where the vent notch portion (380) is not formed, so that venting rupture can be concentrated in a specific portion when venting the battery cell (10).

[0184]

[0185] FIG. 10 is a side cross-sectional view showing a part of the BB' section of FIG. 4, and FIG. 11 is a side cross-sectional view showing another part of the BB' section of FIG. 4.

[0186] With reference to FIGS. 4, 10, and 11, a battery cell (10) according to one embodiment of the present invention will be described in more detail.

[0187] The can lid (300) may further include an injection port (H) and a flat portion (320).

[0188] The injection port (H) may be configured to open toward the interior of the cell housing (200). The injection port (H) may be configured so that the electrolyte can be injected into the interior of the cell housing (200). The injection port (H) may be located approximately in the center of the can lid (300). The center of the injection port (H) may coincide with the center of the can lid (300). The center of the injection port (H) may coincide with the central axis (A) of the winding center hole (C). The injection port (H) may be provided in an approximately circular shape.

[0189] The flat portion (320) may be configured to surround the injection port (H). The flat portion (320) may, for example, surround the injection port (H) along the circumferential direction. The flat portion (320) may be provided with a shape in which at least a portion is flat. The flat portion (320) may be spaced apart from the electrode assembly (100). As described above, when the flat portion (320) is spaced apart from the electrode assembly (100), in addition to the space between the spaced portion (360) and the electrode assembly (100), a void space may also be formed between the flat portion (320) and the electrode assembly (100), thereby securing a larger void space between the can lid (300) and the electrode assembly (100).

[0190] The can lid (300) has a plurality of electrode coupling portions (310) and may further have at least one bridge (350).

[0191] A bridge (350) may be formed to partition any two adjacent electrode coupling portions (310). For example, the bridge (350) may be configured to be positioned between any two circumferentially adjacent electrode coupling portions (310) to partition them from each other. A plurality of bridges (350) may be provided, for example, three.

[0192] The bridge (350) may be extended radially. The bridge (350) may be extended radially from the flat portion (320). The bridge (350) may be extended from the flat portion (320) toward the edge portion (370). Alternatively, the bridge (350) may be extended from the flat portion (320) toward the spaced portion (360).

[0193] By means of the bridge (350), a plurality of electrode coupling parts (310) can be clearly partitioned and spaced apart from each other. The bridge (350) can reinforce the rigidity of the can lid (300). The bridge (350) can be spaced apart from the electrode assembly (310).

[0194] When a plurality of electrode coupling parts (310) are provided, the plurality of electrode coupling parts (310) may be spaced apart from each other, and the aforementioned spacing part (360) and / or bridge (350) may be arranged between adjacent electrode coupling parts (310). For example, the plurality of electrode coupling parts (310) may be spaced apart from each other in the circumferential direction.

[0195] Each of the multiple electrode coupling portions (310) can be positioned at a location relatively closer to the electrode assembly (100) than to the surrounding portion. When the electrode coupling portions (310) are configured in this way, the flatness with respect to the electrode assembly (100) can be stably formed, and the welding quality between the can lid (300) and the electrode assembly (100) can be improved.

[0196] A plurality of electrode coupling portions (310) may be formed and arranged radially and rotationally symmetrically with respect to the center of the can lid (300). Here, the center of the can lid (300) can be understood, for example, as the center of the injection port (H) and may be located on the central axis (A) of the winding center hole (C). Here, being formed and arranged radially and rotationally symmetrically can be understood as being repeatedly formed and arranged at a certain angle with respect to the center of the can lid (300), so that the same arrangement is repeated when rotated by the said certain angle with respect to the center of the can lid (300). Each electrode coupling portion (310) may be formed with the same shape as one another and arranged to be equal to each other with respect to the center of the can lid (300). In this way, when a plurality of electrode coupling parts (310) are symmetrically formed and arranged, stable flatness between the can lid (300) and the electrode assembly (100) can be more easily secured, and the electrical stability of the battery cell (10) can also be improved.

[0197] The electrode coupling portion (310) may be provided in three parts. When the electrode coupling portion (310) is provided in three parts, the multiple electrode coupling portions (310) can easily form a single plane, so stable flatness with the electrode assembly (100) can be more easily secured.

[0198] When multiple electrode coupling portions (310) are provided, a spacing portion (360) may be positioned between two electrode coupling portions (310) and an edge portion (370).

[0199] The electrode coupling portion (310) may be extended toward the flat portion (320) and the edge portion (370). Specifically, the electrode coupling portion (310) may be extended in a centripetal direction toward the flat portion (320), and the electrode coupling portion (310) may be extended radially toward the edge portion (370). In this case, since the welding length (d) between the electrode coupling portion (310) and the foil tab can be extended, the internal resistance of the battery cell (10) can be reduced (see FIG. 10).

[0200] A can lid (300) according to one embodiment of the present invention may further include a plug coupling portion (340). A plug (330) may be inserted and seated in the plug coupling portion (340) and coupled thereto. An injection port (H) may be formed in the center of the plug coupling portion (340). The plug (330) may be configured to seal the injection port (H).

[0201] The plug coupling portion (340) may be provided with an insertion portion (341) and a seating portion (342). A plug (330) may be inserted into the insertion portion (341). The plug (330) may be provided with a protrusion (331) that protrudes to be inserted into the insertion portion (341). The protrusion (331) may be coupled to the insertion portion (341) in a press-fit manner. An injection port (H) may be formed on the inner side of the insertion portion (341), and the injection port (H) may be sealed when the protrusion (331) is inserted into the insertion port.

[0202] A plug (330) may be seated in the seating portion (342). The plug (330) may be provided with an extension portion (332) to be seated in the seating portion (342). The extension portion (332) may be in a shape that extends radially from the insertion portion (341). The seating portion (342) may be formed with a step so that the extension portion (332) can be seated. The extension portion (332) and the seating portion (342) may be welded together.

[0203] As described above, when the can lid (300) further includes a plug coupling portion (340), the coupling between the plug (330) and the can lid (300) is improved, and the injection port (H) can be effectively sealed.

[0204] Meanwhile, the wider the width (b) (radial width) of the seating portion (342) formed from the injection port (H) to the inner end of the flat portion (320), the better the weldability of the extension portion (332) of the plug (330) and the seating portion (342) can be improved. The width (b) can be designed to prevent welding defects of the plug (330) caused by the heat of vaporization of the electrolyte. For example, the width (b) can be formed to be 1.0 mm or more and 2.5 mm or less. For example, the width (b) can be formed to be 2.0 mm (see FIG. 10).

[0205] Meanwhile, the width (c) (radial width) of the flat portion (320) can be formed to an appropriate length to ensure stable flatness. For example, the width (c) can be formed to be 1 mm or more and 4 mm or less. The width (c) can be formed to be, for example, 3 mm or more. If the length (c) is formed to be less than 3 mm, it may be difficult to form the flat portion (320) (see FIG. 10).

[0206] The separation portion (360) may be composed of a picking portion. Specifically, a picking area (361) that can be grasped by a picking device may be formed in the separation portion (360). The diameter of the picking area (361) may be formed, for example, from 1.0 mm to 4.0 mm, or may be formed to exceed 4.0 mm.

[0207] When the separation portion (360) is configured as a picking portion, the can lid (300) can be effectively gripped without the picking equipment coming into contact with the electrode coupling portion (310), thus preventing foreign substances from entering the electrode coupling portion (310) from the picking equipment during the picking operation of the can lid (300), and the can lid (300) can be stably gripped and transported during the assembly process of the battery cell (10).

[0208]

[0209] Figure 12 is a table showing the inner diameter of the injection port, etc., according to the winding center hole size of the electrode assembly.

[0210] Meanwhile, referring further to FIG. 12, the injection port (H) may be a hole through which an electrolyte is injected and, at the same time, a hole through which a welding rod passes. For example, a current collector plate (e.g., a positive current collector plate) and a rivet-shaped terminal (400) may be disposed on the opposite side of the injection port (H) in the battery cell (10), and a welding rod may pass through the injection port (H) and be inserted into the winding center hole (core) (C) of the electrode assembly (100) to weld and join the current collector plate and the terminal (400). Accordingly, it may be preferable for the diameter (a) of the injection port (H) to be formed larger than the diameter of the welding rod to avoid interference with the welding rod. Additionally, the diameter (a) of the injection port (H) may be formed smaller than the inner diameter of the winding center hole (C) to ensure stable injection of the electrolyte.

[0211] FIG. 12 illustrates examples such as the inner diameter of the electrode assembly (100) after unwinding according to the size of each core, the inner diameter (a) of the injection port (H), and the diameter of the welding rod that can be inserted into the injection port (H). Here, the size of the core refers to the inner diameter of the winding center hole (C). The length (a) can be designed considering the diameter of the welding rod and the process margin.

[0212]

[0213] FIG. 13 is a drawing showing a conventional separable can lid, FIG. 14 is a table showing the results of each vent pressure measurement of a battery cell according to an embodiment and a battery cell according to a comparative example, and FIG. 15 is a photograph showing a comparison of the discharge appearance of the electrode assembly after each venting of the battery cell according to an embodiment and a battery cell according to a comparative example.

[0214] The conventional can lid (300) shown in FIG. 13, unlike the conventional can lid (300') shown in FIG. 1, is included in a battery cell that includes a separate current collector plate (e.g., a negative current collector plate) and can be referred to as a separable can lid (300) (300). The separable can lid (300) of FIG. 13 may include a portion formed in a flat shape without curvature along the circumferential direction.

[0215] The left table of FIG. 14 shows the actual vent pressure measurement results of 10 battery cells (10) including a can lid (300) (integrated type) according to the present invention, and the right table of FIG. 14 shows the actual vent pressure measurement results of 9 battery cells including a conventional can lid (300) (separable type) shown in FIG. 13.

[0216] With particular reference to FIG. 14, it can be seen that the notch thickness of the vent notch portion (380) of the can lid (300) (integrated type) according to the present invention and the thickness of the vent notch portion of a different conventional can lid (300) (separated type) are provided at levels of approximately 91 µm and 95 µm, respectively. However, the actual vent pressure of the can lid (300) (integrated type) according to the present invention was measured to be an average of 19.38 kgf / cm^2 (variation 2.05 kgf / cm^2), which is lower than the average actual vent pressure of a different conventional can lid (300) (separated type), which is 28.71 kgf / cm^2 (variation 2.92 kgf / cm^2). That is, the can lid (300) (integrated type) according to the present invention has the advantage of being able to secure the moldability of the vent notch portion (380) by securing a thickness of the vent notch portion (380) similar to that of other conventional can lids (300) (separated type), while also being able to form a lower actual vent pressure.

[0217] FIGS. 15 (a) and FIGS. 15 (b) respectively illustrate the discharge of an electrode assembly during venting of a battery cell (10) including a can lid (300) (integrated type) according to the present invention and a battery cell (10) including a different conventional can lid (300) (separable type). Referring to FIGS. 15, it can be seen that the discharge of the electrode assembly during venting is formed much more smoothly in the battery cell (10) including the can lid (300) (integrated type) according to the present invention compared to the battery cell including a different conventional can lid (300) (separable type).

[0218]

[0219] The actual vent pressure of the vent notch portion (380) of the can lid (300) (integrated type) according to the present invention may be formed to be 18.6 kgf / cm^2 or more and 20.55 kgf / cm^2 or less. If the actual vent pressure of the vent notch portion (380) is less than 18.6 kgf / cm^2, the vent notch portion (380) may break too easily, and the vent notch portion (380) may become vulnerable to external impact. And, if the actual vent pressure of the vent notch portion (380) exceeds 20.55 kgf / cm^2, the vent notch portion (380) may not break easily, and thus smooth venting performance of the battery cell (10) may not be secured.

[0220]

[0221] As the battery cell (10) according to the present invention can be configured as in the various embodiments described above, various dimensions such as the welding flat area welding length of the can lid (300), the electrode coupling portion (310), the winding center hole (C), the injection port (H), the flat portion (320), the bridge (350), the gap portion (360), the edge portion (370), and the bent notch portion (380) can be matched.

[0222]

[0223] FIG. 16 is a drawing showing a battery pack according to one embodiment of the present invention.

[0224] Referring to FIG. 16, the battery pack (30) according to the present invention may include at least one battery cell (10) according to the present invention. The battery pack (30) may include a pack case (20) that accommodates at least one battery cell (10).

[0225] In the drawing, for the convenience of drawing, components such as busbars, cooling units, and external terminals for electrical connection of the battery cells (10) have been omitted. The structure of a plurality of battery cells (10) for manufacturing the battery pack (30) has been described above as an example.

[0226]

[0227] FIG. 17 is a drawing showing an automobile according to one embodiment of the present invention.

[0228] Referring to FIG. 17, a battery pack (30) according to one embodiment of the present invention may be applied to a vehicle (40), such as an electric vehicle or a hybrid vehicle. That is, the vehicle (40) according to the present invention may include the battery pack (30) according to the present invention. The battery pack (30) may be installed in the vehicle body frame or trunk space under the vehicle seat. In addition, the vehicle (40) according to the present invention may include various other components included in the vehicle (40) in addition to the battery pack (30). For example, the vehicle (40) according to one embodiment of the present invention may include, in addition to the battery pack (30) according to the present invention, a vehicle body, a motor, a control device such as an ECU (electronic control unit), etc.

[0229] In addition, it goes without saying that the battery pack (30) according to the present invention may also be provided in other devices, mechanisms, and facilities, such as an energy storage system using a secondary battery, in addition to a vehicle (40).

[0230]

[0231] Meanwhile, although terms indicating direction such as up and down have been used in this specification, these terms are used merely for convenience of explanation, and it is obvious to a person skilled in the art that they may vary depending on the location of the object or the position of the observer.

[0232] Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims set forth below by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed above should be considered in an illustrative rather than a restrictive sense. That is, the scope of the true technical spirit of the present invention is indicated in the claims, and all variations within the equivalent scope thereof should be interpreted as being included in the present invention.

[0233] [Explanation of the symbol]

[0234] 10: Battery cell

[0235] 20 : Pack case

[0236] 30: Battery pack

[0237] 40 : Car

[0238] 100 : Electrode assembly

[0239] 112 : Mujibu

[0240] 112a : First nostril

[0241] 112b : Second undisturbed part

[0242] 200 : Cell housing

[0243] 210 : Opening

[0244] 220 : Closure

[0245] 300 : Can lid

[0246] 310: Electrode coupling part

[0247] 320 : Flat section

[0248] 330 : Plug

[0249] 331 : Protrusion

[0250] 332 : Extension

[0251] 340 : Plug connection part

[0252] 341 : Insert

[0253] 342 : Seating part

[0254] 350 : Bridge

[0255] 360 : Separation

[0256] 361 : Picking Area

[0257] 370 : Edge part

[0258] 380 : Vent notch

[0259] 400 : Electrode terminal

[0260] 500 : Insulating gasket

[0261] 600 : Houseplate

[0262] 700 : Insulator

[0263] C: Winding center hole

[0264] A : Central axis

[0265] H: Injection port

[0266] P1: 1st point

[0267] P2 : 2nd point

[0268] P3 : 3rd point

[0269] Po1 : Part 1

[0270] Po2: Part 2

[0271] Po3: Part 3

[0272] S1 : Section 1

[0273] S2 : Section 2

[0274] SC: Stress concentration area

Claims

1. An electrode assembly provided by being wound around the central axis of a central hole with a separator interposed between electrodes of different polarities; A cell housing that accommodates the above electrode assembly and has an opening on one side; and It includes one end of the cell housing and a can lid coupled to the electrode assembly, and The above can lid is, A battery cell characterized by having a bent notch portion formed by notching at the radially inner side of the edge, wherein the thicknesses at at least two locations are formed differently from each other.

2. In Paragraph 1, The above-mentioned bent notch portion is, A battery cell characterized by at least a portion extending along the circumferential direction.

3. In Paragraph 1, A cross-section of the above-mentioned bent notch viewed from the circumferential direction is, A battery cell characterized by being formed in a V-shape or a U-shape.

4. In Paragraph 1, The thickness of the bent notch portion in the section corresponding to the part of the can lid where stress is concentrated due to the internal pressure of the battery cell is, A battery cell characterized by being formed thinner than the thickness of the above-mentioned bent notch portion in the remaining other sections.

5. In Paragraph 1, The above can lid is, At least one electrode coupling portion disposed at a position relatively closer to the electrode assembly than the surrounding portion and coupled to the electrode assembly; and It has at least one spaced portion spaced apart from the electrode assembly, and The above-mentioned bent notch portion is, A first point is located in a section corresponding to the electrode coupling part, a second point is located in a section corresponding to the separation part, and a third point is located between the first point and the second point. The thickness of the bent notch portion at the third point is, A battery cell characterized by being formed thinner than the thickness of the vent notch portion at the first point and the thickness of the vent notch portion at the second point.

6. In Paragraph 5, A battery cell characterized in that the thickness of the vent notch portion at the first point and the thickness of the vent notch portion at the second point are formed to be the same as each other.

7. In Paragraph 5, The above-mentioned bent notch portion is, A battery cell characterized by being disposed on the outer side of the electrode coupling portion in the radial direction.

8. In Paragraph 1, The above can lid is, It is configured to be coupled to one end of the cell housing and further comprises an edge portion formed on the edge of the can lid, and The above-mentioned bent notch portion is, A battery cell characterized by being provided on the radially inner side of the above edge portion.

9. In Paragraph 1, The above-mentioned bent notch portion is, A battery cell characterized in that the thickness of each of at least two locations is formed differently from each other to form a discontinuous thickness change between the two locations.

10. In Paragraph 1, The above-mentioned bent notch portion is, A battery cell characterized in that the thickness of each of at least two locations is formed differently from each other to form a gradual thickness change between the two locations.

11. In Paragraph 1, The above-mentioned bent notch portion is, A battery cell characterized by being formed only on one of the upper surface far from the electrode assembly or the lower surface close to the electrode assembly of the can lid.

12. In Paragraph 1, The above-mentioned bent notch portion is, A battery cell characterized by being formed on both the upper surface far from the electrode assembly and the lower surface close to the electrode assembly of the can lid.

13. In Paragraph 1, The above-mentioned bent notch portion is, In some sections, it is formed only on one of the upper surface far from the electrode assembly and the lower surface close to the electrode assembly of the can lid, and A battery cell characterized by being formed on both the upper and lower surfaces of the can lid in the remaining sections.

14. In Paragraph 1, The above-mentioned bent notch portion is, A battery cell characterized by being formed by extending in a continuous form.

15. In Paragraph 1, The above-mentioned bent notch portion is, A battery cell characterized by being formed by extending in a discontinuous shape.

16. A battery pack characterized by including at least one battery cell according to any one of claims 1 to 15.

17. An automobile characterized by including at least one battery pack according to paragraph 16.

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