Current collector, battery cell, battery pack and automobile including the same

Abstract

According to one embodiment of the present invention, a battery cell includes: an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, the first electrode including a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side and accommodating the electrode assembly through the opening; and a current collector including a support portion disposed on an upper portion of the electrode assembly, a tab coupling portion extending from the support portion and coupling with the first uncoated portion, and a housing coupling portion extending from the support portion and electrically coupling with an inner surface of the battery housing, wherein a fracture portion having a strength lower than that of a surrounding region is provided at a boundary between the support portion and the tab coupling portion.

Description

[Technical Field]

[0001] The present invention relates to a current collector, a battery cell, a battery pack, and a vehicle including the same.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0077637 filed on June 16, 2023, Korean Patent Application No. 10-2024-0030857 filed on March 4, 2024, and Korean Patent Application No. 10-2024-0067269 filed on May 23, 2024, and the contents disclosed in the specifications and drawings of those applications are incorporated herein in their entirety. [Background technology]

[0003] Secondary batteries, which are easily applicable to various products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs), hybrid electric vehicles (HEVs), etc. These secondary batteries are attracting attention as a new energy source that not only has the primary advantage of dramatically reducing the use of fossil fuels but also is environmentally friendly because they do not produce any by-products associated with energy use and improve energy efficiency.

[0004] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of such a unit secondary battery cell is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack is constructed by connecting multiple battery cells in series. Alternatively, a battery pack can be constructed by connecting multiple battery cells in parallel depending on the required charge / discharge capacity of the battery pack. Therefore, the number of battery cells included in the battery pack can be variously set depending on the required output voltage and / or charge / discharge capacity.

[0005] On the other hand, if heat is not managed in a battery cell, phenomena such as thermal runaway can occur, in which the electrochemical cell self-heats in an uncontrollable manner, changing the environment in a way that further accelerates temperature changes. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a battery cell in which flames generated inside the battery cell can be smoothly exhausted when thermal runaway occurs.

[0007] Furthermore, the present invention prevents damage to the beading portion of the battery cell when thermal runaway occurs.

[0008] The present invention prevents pinholes from occurring in the beading portion of a battery cell when thermal runaway occurs.

[0009] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description of the invention. [Means for solving the problem]

[0010] According to one embodiment of the present invention, a battery cell includes: an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, the first electrode including a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side and accommodating the electrode assembly through the opening; and a current collector including a support portion disposed on an upper portion of the electrode assembly, a tab coupling portion extending from the support portion and coupling with the first uncoated portion, and a housing coupling portion extending from the support portion and electrically coupling with an inner surface of the battery housing, wherein a fracture portion having a strength lower than that of a surrounding region is provided at a boundary between the support portion and the tab coupling portion.

[0011] For example, the break may include a notch line that includes a plurality of notches.

[0012] The current collector according to an embodiment of the present invention may include a through-hole configured to penetrate the current collector.

[0013] For example, the through hole may be located at the notch line.

[0014] According to an embodiment of the present invention, the through-hole may be located at the center of the boundary between the support portion and the tab coupling portion.

[0015] According to an embodiment of the present invention, at least one through hole may be provided in the support portion.

[0016] According to an embodiment of the present invention, at least one through-hole may be provided in the tab coupling portion.

[0017] The notch line according to an embodiment of the present invention may be configured to have a curved shape.

[0018] According to an embodiment of the present invention, the tab connection portion may be configured to have a width greater than that of the housing connection portion.

[0019] According to an embodiment of the present invention, the first non-coating portion and the tab connecting portion may be connected by welding along the radial direction of the electrode assembly.

[0020] For example, a weld bead may be formed between the first non-coated portion and the tab connecting portion.

[0021] In this case, the weld beads may form a linear weld pattern extending along the radial direction of the electrode assembly.

[0022] Here, the weld pattern is configured to be perpendicular to the notch line.

[0023] For example, the tab connection portion may be located below the lower surface of the beading portion.

[0024] According to one embodiment, the present invention provides a current collector including: a support portion disposed on an upper portion of an electrode assembly; a tab coupling portion extending from the support portion and electrically coupling with the electrode assembly; and a housing coupling portion extending from the support portion and electrically coupling with an inner surface of a battery housing in which the electrode assembly is accommodated. A fracture portion having a lower strength than a surrounding region may be provided at a boundary between the support portion and the tab coupling portion.

[0025] Alternatively, the present invention provides a battery pack including at least one battery cell according to any of the above-described embodiments.

[0026] The present invention also provides a vehicle including at least one battery pack according to the above-described embodiment.

[0027] Furthermore, the present invention provides a battery module including at least one battery cell according to the above-described embodiments.

[0028] The present invention is an energy storage system that includes at least one battery module according to the above-described embodiments.

[0029] According to yet another embodiment, a battery cell of the present invention includes an electrode assembly having a core and an outer circumferential surface defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, wherein the first electrode includes a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side and accommodating the electrode assembly through the opening; and a current collector including a support portion disposed on an upper portion of the electrode assembly, a tab connecting portion extending from the support portion and connecting to the first uncoated portion, and a housing connecting portion extending from the support portion and electrically connecting to an inner surface of the battery housing, wherein the current collector is provided with a channel or path capable of venting flames to the outside in the event of thermal runaway in the electrode assembly.

[0030] For example, the passage includes a break portion at the boundary between the support portion and the tab connection portion that is configured to have lower strength than the surrounding area, and the break portion includes a notch line that includes a plurality of notches. [Effects of the Invention]

[0031] According to an embodiment of the present invention, when thermal runaway occurs, a flame generated inside a battery cell can be smoothly exhausted.

[0032] According to an embodiment of the present invention, it is possible to effectively prevent damage to the beading portion of the battery cell when thermal runaway occurs.

[0033] For example, the present invention can prevent pinholes from occurring in the beading portion of the battery cell when thermal runaway occurs.

[0034] However, the effects of the present invention are not limited to the effects described above, and other effects of the present invention not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0035] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention, so the present invention should not be interpreted as being limited to the matters described in the drawings. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a diagram illustrating a battery cell according to an embodiment of the present invention; [Figure 2] FIG. 2 is a vertical cross-sectional perspective view of FIG. [Figure 3] FIG. 2 is a longitudinal cross-sectional view of the battery cell of FIG. 1. [Figure 4] FIG. 2 is a perspective view illustrating a current collector according to an embodiment of the present invention. [Figure 5] FIG. 10 is a perspective view illustrating a current collector according to another embodiment of the present invention. [Figure 6] FIG. 10 is a perspective view illustrating a current collector according to still another embodiment of the present invention. [Figure 7] FIG. 10 is a perspective view illustrating a current collector according to still another embodiment of the present invention. [Figure 8] FIG. 10 is a perspective view illustrating a current collector according to still another embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view illustrating a current collector according to still another embodiment of the present invention. [Figure 10] 10A and 10B are diagrams illustrating a case where thermal runaway occurs in a battery cell to which a conventional current collector is applied. [Figure 11] 10A and 10B are diagrams illustrating a case where thermal runaway occurs in a battery cell according to an embodiment of the present invention. [Figure 12] 10A and 10B are diagrams illustrating another case where thermal runaway occurs in a battery cell according to an embodiment of the present invention. [Figure 13] 10A and 10B are diagrams illustrating yet another case where thermal runaway occurs in a battery cell according to an embodiment of the present invention. [Figure 14]1 is a diagram illustrating a battery pack including a battery cell according to an embodiment of the present invention; [Figure 15] FIG. 15 is a diagram for explaining a vehicle including the battery pack of FIG. 14.

[0037] In some of the accompanying drawings, corresponding components are given the same reference numerals. Those skilled in the art will appreciate that the drawings are intended to illustrate components simply and clearly and are not necessarily drawn to scale. For example, to facilitate understanding of the various embodiments, the dimensions of some components shown in the drawings may be exaggerated relative to other components. Furthermore, elements of known technology that are useful or essential in commercially viable embodiments may be omitted so as not to interfere with the spirit of the various embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0038] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventor himself can appropriately define the concepts of terms in order to best describe the invention. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical ideas of the present invention, and therefore various equivalents and modifications that can be substituted therefor may exist at the time of filing this application.

[0039] In addition, in order to facilitate understanding of the invention, some components may be exaggerated in the accompanying drawings rather than being drawn to scale, and the same reference numerals may be used to refer to the same components in different embodiments.

[0040] When two comparison objects are identical, it means that they are "substantially identical." Therefore, "substantially identical" may include deviations that are considered low in the art, for example, deviations within 5%. Furthermore, when any parameter is uniform in a given region, it may mean uniformity on average.

[0041] Terms such as "first" and "second" are used to describe various components, but these terms are not intended to limit the components. These terms are used to distinguish only one component from another, and unless otherwise specified, the first component may be the second component.

[0042] Furthermore, throughout the specification, unless otherwise specified, each element may be singular or plural.

[0043] When any structure is placed "on top (or bottom)" of a component or "above (or below)" a component, it can mean that the structure is placed directly on the top (or bottom) surface of the component, but also that other structures may be interposed between the component and any structure placed above (or below) the component.

[0044] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" by other components.

[0045] Throughout the specification, unless otherwise specified, "A and / or B" means "A," "B," or "A and B," and "C through D" means at least C and at most D, unless otherwise specified.

[0046] As used in this specification, the terms "about," "approximately," and "substantially" are used to mean a range of or approximation to a numerical value or degree, taking into consideration inherent manufacturing and material tolerances, and are used to prevent infringers from unfairly exploiting the disclosure content in which exact or absolute numerical values ​​provided to aid in the understanding of the present invention are mentioned.

[0047] For ease of explanation, in this specification, the direction along the longitudinal direction of the winding shaft of the electrode assembly 10 wound in a jelly roll shape is referred to as the axial direction (Y direction). The direction surrounding the winding shaft is referred to as the circumferential direction or circumferential direction (X direction). The direction approaching the winding shaft or the direction away from the winding shaft is referred to as the radial direction. Of these, the direction approaching the winding shaft is particularly referred to as the mesial direction, and the direction away from the winding shaft is particularly referred to as the centrifugal direction.

[0048] When thermal runaway occurs in a secondary battery, pinholes may occur on the side of the battery cell. In this case, the thermal runaway may directly damage the surrounding battery cells, causing them to explode one after another and resulting in a chain fire. Therefore, it is necessary to reduce the frequency of pinhole occurrence.

[0049] Furthermore, considering that pinholes frequently occur in the beading portion when thermal runaway occurs, when the flame does not smoothly escape to the vent portion but instead travels to the side, the flame directly contacts the surrounding beading portion, causing pinholes. Therefore, the present invention provides an electrode assembly structure that can smoothly escape the flame.

[0050] For example, a battery cell according to an embodiment of the present invention may be provided with a channel or path that allows flames to be smoothly discharged to a vent portion when thermal runaway occurs.

[0051] Fig. 1 is a diagram illustrating a battery cell 1 according to an embodiment of the present invention, and Fig. 2 is a vertical cross-sectional perspective view of Fig. 1. Fig. 3 is a vertical cross-sectional view of the battery cell 1 of Fig. 1.

[0052] 1 and 2, a battery cell 1 according to one embodiment of the present invention includes an electrode assembly 10, a battery housing 20, and a current collector 30. In addition, the battery cell 1 may further include a housing cover 40. The present invention is not limited by the shape of the battery, and is also applicable to batteries of other shapes, for example, prismatic batteries.

[0053] 2 and 3, the electrode assembly 10 includes a first non-coated portion 11 and a second non-coated portion 12. For example, the electrode assembly 10 according to one embodiment has a winding structure in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed therebetween around a winding shaft with a separator interposed therebetween. That is, the electrode assembly 10 according to the present invention may be a jelly-roll type electrode assembly 10. In this case, a separator may be further provided on the outer circumferential surface of the electrode assembly 10 for insulation from the battery housing 20.

[0054] The first electrode according to an embodiment of the present invention includes a first electrode current collector and a first electrode active material coated on one or both surfaces of the first electrode current collector. An uncoated portion where the first electrode active material is not coated is present at one end of the first electrode in the width direction (parallel to the height direction of the battery cell 1 shown in FIG. 1). That is, the first electrode includes an uncoated portion at a long edge along the winding direction that is not coated with an active material and is exposed to the outside of the separator. The uncoated portion functioning as a first electrode tab is hereinafter referred to as a first uncoated portion 11. The first uncoated portion 11 is provided at an upper portion in the height direction (parallel to the height direction of the battery cell 1 shown in FIG. 1) of the electrode assembly 10 housed within the battery housing 20. That is, the first electrode includes a first uncoated portion 11 at a long edge that is not coated with an active material layer and is exposed to the outside of the separator, and at least a portion of the first uncoated portion 11 is used as an electrode tab. The first non-coated portion 11 may be, for example, a negative electrode tab.

[0055] Meanwhile, at least a portion of the first non-applied portion 11 may include a plurality of segment pieces divided along the winding direction of the electrode assembly 10. In this case, the plurality of segment pieces may be bent along the radial direction of the electrode assembly 10.

[0056] 2 and 3, according to an embodiment of the present invention, the plurality of segments of the folded first non-coating portion 11 may be overlapped to form a folded surface. In this case, a tab coupling portion 32 of a current collector 30, which will be described later, may be bonded to the folded surface. The tab coupling portion 32 may be bonded to a region where the plurality of segments are overlapped. In this case, welding may be performed on a certain region while the tab coupling portion 32 is mounted on the folded surface of the first non-coating portion 11. That is, the tab coupling portion 32 may be bonded to a region where the plurality of segments of the first non-coating portion 11 are overlapped. For example, as can be seen in FIG. 5, the tab coupling portion 32 may have at least one welded portion where a certain region is welded while mounted on the folded surface of the first non-coating portion 11.

[0057] According to an embodiment of the present invention, the second electrode includes a second electrode current collector and a second electrode active material coated on one or both sides of the second electrode current collector. The other end of the second electrode in the width direction (parallel to the height direction of the battery cell 1 shown in FIG. 1 ) has an uncoated portion where the second electrode active material is not coated. That is, the second electrode includes an uncoated portion at a long edge along the winding direction that is not coated with an active material and is exposed to the outside of the separator. The uncoated portion functioning as a second electrode tab is hereinafter referred to as a second uncoated portion 12. For example, the second uncoated portion 12 is provided at a lower portion in the height direction of the electrode assembly 10 housed in the battery housing 20. That is, the second electrode includes a second uncoated portion 12 at a long edge that is not coated with an active material and is exposed to the outside of the separator, and at least a portion of the second uncoated portion 12 is used as an electrode tab. The second uncoated portion 12 may be, for example, a positive electrode tab.

[0058] Meanwhile, in the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may be any active material known in the art without any limitations.

[0059] Referring to FIG. 1 according to an embodiment of the present invention, the battery housing 20 is a substantially cylindrical container having an opening on one side and is made of a conductive metal material. The side surface of the battery housing 20 and the bottom surface opposite the opening are generally integrally formed. That is, the battery housing 20 generally has an open upper end in its height direction and a closed lower end. The bottom surface of the battery housing 20 may be substantially flat. The battery housing 20 receives the electrode assembly 10 through an opening formed on one side in its height direction. The battery housing 20 may also receive an electrolyte through the opening.

[0060] For example, the battery housing 20 includes a beading portion 21 formed at an end adjacent to an opening provided at the upper end of the battery housing 20. The battery housing 20 further includes a crimping portion 22 formed at the beading portion 21. The beading portion 21 has a shape in which the outer circumferential surface of the battery housing 20 is pressed to a predetermined depth. Alternatively, the beading portion 21 may have a shape in which it is pressed inward in a region between an opening formed on one side of the battery housing 20 and a receiving portion that receives the electrode assembly 10.

[0061] The beading portion 21 according to an embodiment of the present invention is formed on the upper portion of the electrode assembly 10. The inner diameter of the battery housing 20 in the area where the beading portion 21 is formed is smaller than the diameter of the electrode assembly 10. At least one tab coupling portion 32 of the current collector 30, which will be described later, may be located below the beading portion 21. Alternatively, the tab coupling portion 32 may be located below the bottom surface of the beading portion 21.

[0062] The beading portion 21 according to an embodiment of the present invention provides a support surface on which the housing cover 40 is mounted. The beading portion 21 may also provide a support surface on which at least a portion of the periphery of the current collector 30 (described later) is mounted and coupled. That is, at least a portion of the periphery of the current collector 30 and / or the periphery of the housing cover 40 may be mounted on the upper surface of the beading portion 21. In order to stably support at least a portion of the periphery of the current collector 30 and / or the periphery of the housing cover 40, the upper surface of the beading portion 21 may extend in a direction substantially parallel to the lower surface of the battery housing 20, i.e., in a direction substantially perpendicular to the sidewall of the battery housing 20.

[0063] The beading portion 21 according to an embodiment of the present invention prevents the electrode assembly 10, which has a size approximately corresponding to the inner diameter of the battery housing 20, from slipping out of the opening formed at the upper end of the battery housing 20, and may function as a support portion 31 on which the housing cover 40 is mounted. The beading portion 21 may function as a support portion 31 for fixing not only the housing cover 40 but also the contact portion of the current collector 30, the sealing gasket G1, etc.

[0064] According to an embodiment of the present invention, the crimping portion 22 is formed on the beading portion 21. The crimping portion 22 is extended and bent to surround the periphery of the housing cover 40 disposed on the beading portion 21. The housing cover 40 is fixed to the beading portion 21 due to the shape of the crimping portion 22.

[0065] 1 and 2, a current collector 30 according to an embodiment of the present invention is housed inside a battery housing 20 and is electrically connected to the electrode assembly 10 and the battery housing 20. That is, the current collector 30 electrically connects the electrode assembly 10 and the battery housing 20.

[0066] Fig. 4 is a perspective view illustrating a current collector 30 according to one embodiment of the present invention, and Fig. 5 is a perspective view illustrating a current collector 30 according to another embodiment of the present invention. Figs. 6 to 9 are perspective views illustrating a current collector 30 according to still another embodiment of the present invention.

[0067] 4 to 7, the current collector 30 according to an embodiment of the present invention includes a support portion 31 located on one side of the electrode assembly 10, a tab connecting portion 32 extending from the support portion 31 and connecting to the first non-coated portion 11, and a housing connecting portion 33 extending from the support portion 31 and connecting to the inner surface of the battery housing 20.

[0068] 4 to 9, a break portion 34 having a lower strength than the surrounding region may be provided at the boundary between the support portion 31 and the tab coupling portion 32. That is, the break portion 34 may be structurally weaker than the surrounding region. For example, the break portion 34 may be thinner than the surrounding region. Or, the break portion 34 may be denser than the surrounding region. According to one embodiment of the present invention, the break portion 34 may include, for example, a notch line NL including a plurality of notches, or a through hole HC.

[0069] According to the structure in which the breaking portion 34 is provided at the boundary between the support portion 31 and the tab coupling portion 32 according to an embodiment of the present invention, when a thermal runaway phenomenon occurs inside the battery cell 1 and a flame is emitted, strong pressure is applied to the breaking portion 34, causing a fracture at the breaking portion 34. As a result, the support portion 31 of the current collector 30 may be separated from the tab coupling portion 32. That is, when a flame is emitted inside the battery cell 1, the breaking portion 34 is broken, causing the tab coupling portion 32 of the current collector 30 to be separated. As a result, the fracture at the breaking portion 34 allows a flame generated inside the battery cell 1 to be smoothly vented to the outside.

[0070] 5 to 9, the current collector 30 according to an embodiment of the present invention may include through-holes HC configured to penetrate the current collector 30. The through-holes HC may be circular as shown in FIG. 5, but are not limited thereto. For example, the through-holes HC may be circular or have other polygonal shapes such as triangles and rectangles. The through-holes HC allow flames generated inside the battery cell 1 to be smoothly exhausted.

[0071] For example, if a thermal runaway phenomenon occurs in the electrode assembly 10, the current collector 30 is located on the upper side of the electrode assembly 10. Therefore, according to the structure of the conventional battery cell 1, the flame generated in the electrode assembly 10 is blocked by the current collector 30 and is difficult to smoothly evacuate. This causes a problem in that the flame moves toward the beading portion 21 located in the peripheral area of ​​the electrode assembly 10 and the current collector 30, causing a pinhole in the beading portion 21. If a pinhole is formed in the beading portion 21, it is highly likely that other battery cells 1 located around the battery cell 1 where the fire occurred will be directly damaged. Therefore, the spread of the fire to other battery cells 1 is inevitable.

[0072] In contrast, according to one embodiment of the present invention, the current collector 30 is provided with through holes HC, and flames generated in the electrode assembly 10 are discharged through the through holes HC. This prevents the flames from spreading toward the beading portion 21. As a result, according to the present invention, the beading portion 21 can be prevented from being damaged by the flames. Alternatively, according to the present invention, the formation of pinholes in the beading portion 21 can be effectively prevented.

[0073] According to an embodiment of the present invention, the through hole HC may be located at a notch line NL of the breaking portion 34. In this structure, by including both the breaking portion 34 and the through hole HC, the strength of the boundary region between the support portion 31 and the tab coupling portion 32 may be configured to be lower than the strength of the surrounding region, compared to a structure including only one of the breaking portion 34 and the through hole HC.

[0074] For example, referring to FIG. 5, by providing through holes HC in the current collector 30, vent gas and / or flames generated due to thermal runaway or the like on the electrode assembly 10 side can be smoothly discharged to the outside through the through holes HC.

[0075] 5 according to an embodiment of the present invention, when the through-hole HC is formed in the boundary region between the support portion 31 and the tab coupling portion 32, the material of the current collector 30 is removed in the region where the through-hole HC is formed, thereby reducing the width of the connection portion constituting the boundary region between the support portion 31 and the tab coupling portion 32. As a result, the strength of the boundary region between the support portion 31 and the tab coupling portion 32 can be configured to be lower than the strength of the surrounding region. As a result, when vent gas generated due to thermal runaway or the like is ejected upward in the electrode assembly 10, only the tab coupling portion 32 separates and falls. As a result, flames generated in the electrode assembly 10 can be smoothly exhausted through the space formed by the separation and falling of the tab coupling portion 32.

[0076] 5 according to an embodiment of the present invention, when a notch line NL including a plurality of notches is formed in the boundary region between the support portion 31 and the tab coupling portion 32, the thickness and / or density of the current collector 30 is reduced in the region where the notches are formed, and therefore the strength of the boundary region between the support portion 31 and the tab coupling portion 32 may be configured to be lower than the strength of the surrounding region. As a result, when vent gas generated due to thermal runaway or the like on the electrode assembly 10 side is ejected upward, only the tab coupling portion 32 may separate and fall. As a result, flames generated in the electrode assembly 10 can be smoothly exhausted through the space formed by the separation and fall of the tab coupling portion 32.

[0077] 5 according to an embodiment of the present invention, the through hole HC may be configured to be located at the center of the boundary between the support part 31 and the tab coupling part 32. That is, the connection portions of the boundary region between the support part 31 and the tab coupling part 32 provided on both sides of the through hole HC may be configured to have the same width.

[0078] According to this structure, the connection portions at the boundary between the support portions 31 on both sides of the through hole HC and the tab connecting portion 32 have the same width, so when the tab connecting portion 32 is subjected to upward pressure by vent gas, the same force is applied to each connection portion. As a result, all of the tab connecting portions 32 are broken, which prevents the tab connecting portion 32 from being incompletely separated due to the breakage of only one connection portion.

[0079] According to still another embodiment of the present invention, at least one through hole HC may be provided in the support portion 31 .

[0080] For example, referring to FIG. 6, a plurality of through holes HC may be provided in the support portion 31 of the current collector 30. Meanwhile, the through holes HC may be, for example, circular, but are not necessarily limited to this. For example, a plurality of through holes HC may be provided along the periphery of the current collector hole H2. For example, FIG. 6 shows an embodiment in which four through holes HC are provided along the periphery of the current collector hole H2.

[0081] When the through holes HC are provided in the support portion 31, vent gas and / or flame generated from the electrode assembly 10 can be smoothly discharged to the outside. That is, because the top of the electrode assembly 10 is covered by the current collector 30, in order for gas and / or flame to be discharged from the electrode assembly 10, holes must be present in the current collector 30 or the current collector 30 must be separated. In this regard, according to one embodiment of the present invention, a plurality of through holes HC are provided in the current collector 30, thereby enabling smooth discharge of gas and / or flame generated from the electrode assembly 10. In particular, the core side region of the electrode assembly 10 is covered by the support portion 31 of the current collector 30. However, when a plurality of through holes HC are provided in the support portion 31, vent gas and / or flame generated in the core side region of the electrode assembly 10 can be smoothly discharged upward.

[0082] According to an embodiment of the present invention, at least one through hole HC may be provided in the tab coupling portion 32 .

[0083] For example, referring to Fig. 7, the through holes HC may be provided in each of the tab coupling portions 32 of the current collector 30. For example, Fig. 7 shows an embodiment in which the through holes HC are provided in each region corresponding to the tab coupling portions 32.

[0084] When the through holes HC are provided in the tab coupling portion 32, vent gas and / or flame generated in the electrode assembly 10 can be smoothly discharged to the outside through the through holes HC. In particular, the outer peripheral region of the electrode assembly 10 is covered by the tab coupling portion 32 of the current collector 30, and when a plurality of through holes HC are provided in the tab coupling portion 32, vent gas and / or flame generated in the outer peripheral region of the electrode assembly 10 can be smoothly discharged upward.

[0085] However, if too many through holes HC are provided in the tab coupling portion 32, the area available for welding the tab coupling portion 32 to the electrode assembly 10 may be excessively reduced. As a result, the welding area between the tab coupling portion 32 and the electrode assembly 10 is reduced, weakening the bonding strength. Therefore, it is necessary to appropriately adjust the area of ​​the tab coupling portion 32 and the number of through holes HC formed therein.

[0086] 8 according to an embodiment of the present invention, the through-hole HC may be formed in the support portion 31 of the current collector 30 and may also be formed in the tab coupling portion 32 of the current collector 30. Referring to FIG. 9 according to an embodiment of the present invention, the through-hole HC may be formed in the boundary region between the support portion 31 and the tab coupling portion 32 and may also be formed in the support portion 31. Although not shown, in yet another embodiment of the present invention, the through-hole HC may be formed in the boundary region between the support portion 31 and the tab coupling portion 32 and may also be formed in the tab coupling portion 32. Furthermore, the position of the through-hole HC is not limited to the above embodiment, and the through-hole HC may be formed in any position or combination of positions in the current collector 30 depending on the situation, and such an embodiment is included in the scope of the present invention.

[0087] The notch lines NL according to an embodiment of the present invention may be configured to have a curved shape. For example, referring to FIGS. 4 to 9, the notch lines NL may be configured to have a curved shape that bulges toward the center of the current collector 30. Alternatively, although not shown, the notch lines NL may be configured to have a curved shape that is recessed toward the center of the current collector 30. Alternatively, the notch lines NL may be configured to have a substantially straight shape. In other words, the shape of the notch lines NL is not limited to any one shape and may be configured in various shapes, and such various embodiments are included within the scope of the present invention.

[0088] According to an embodiment of the present invention, the tab coupling portion 32 may have a width greater at a position spaced a predetermined distance from the connection portion toward an end portion of the tab coupling portion 32 in the longitudinal direction than at the connection portion between the tab coupling portion 32 and the support portion 31. For example, referring to FIGS. 4 to 9, the tab coupling portion 32 may have a substantially fan-like shape in which the width greater at a position spaced a predetermined distance from the connection portion toward an end portion of the tab coupling portion 32 in the longitudinal direction than at the connection portion between the tab coupling portion 32 and the support portion 31.

[0089] According to this structure, the tab coupling portion 32 can be configured with a narrow width at the connection portion between the tab coupling portion 32 and the support portion 31, thereby reducing the strength of the connection portion between the tab coupling portion 32 and the support portion 31. As a result, if a thermal runaway phenomenon occurs inside the battery cell 1 and a flame is emitted, strong pressure may be applied to the connection portion between the tab coupling portion 32 and the support portion 31, causing rupture at the connection portion between the tab coupling portion 32 and the support portion 31. As a result, the support portion 31 of the current collector 30 may be separated from the tab coupling portion 32. That is, if a flame is emitted from inside the battery cell 1, the connection portion between the tab coupling portion 32 and the support portion 31 may rupture, causing the current collector 30 to be separated from the tab coupling portion 32 of the current collector 30. As a result, rupture at the connection portion between the tab coupling portion 32 and the support portion 31 allows the flame generated inside the battery cell 1 to be smoothly vented to the outside.

[0090] Furthermore, with this structure, the width at a position spaced a predetermined distance from the connection portion toward the longitudinal end of the tab coupling portion 32 is increased, thereby ensuring a wide overall cross-sectional area of ​​the tab coupling portion 32. That is, the tab coupling portion 32 has a substantially fan-like shape, ensuring a wide contact area between the tab coupling portion 32 and the electrode assembly 10. This facilitates welding of the tab coupling portion 32 and the electrode assembly 10. Furthermore, the wide contact area between the tab coupling portion 32 and the electrode assembly 10 effectively reduces the internal resistance of the battery.

[0091] According to an embodiment of the present invention, the longitudinal end of the tab coupling portion 32 may have a substantially arc shape to correspond to the inner peripheral surface of the battery housing 20. For example, referring to FIGS. 4 to 9, the longitudinal end of the tab coupling portion 32 may have an arc shape, so that the tab coupling portion 32 may be configured to have a substantially fan shape.

[0092] According to this structure, the longitudinal end of the tab coupling portion 32 can be configured to be farther away from the center of the current collector 30, thereby ensuring a wide overall cross-sectional area of ​​the tab coupling portion 32. That is, the tab coupling portion 32 has a substantially fan-like shape, ensuring a wide contact area between the tab coupling portion 32 and the electrode assembly 10. This facilitates welding of the tab coupling portion 32 and the electrode assembly 10. Furthermore, the wide contact area between the tab coupling portion 32 and the electrode assembly 10 effectively reduces the internal resistance of the battery.

[0093] According to an embodiment of the present invention, the tab coupling portion 32 may be configured to have a width greater than that of the housing coupling portion 33. For example, referring to Figures 4 to 9, the tab coupling portion 32 may be formed to have a wide, approximately fan-like shape, while the housing coupling portion 33 may be configured to have a substantially rectangular band shape.

[0094] This structure ensures a wide overall cross-sectional area of ​​the tab coupling portion 32. That is, the tab coupling portion 32 is configured to have a width greater than that of the housing coupling portion 33, thereby ensuring a wide contact area between the tab coupling portion 32 and the electrode assembly 10. This allows smooth welding of the tab coupling portion 32 and the electrode assembly 10. Furthermore, the wide contact area between the tab coupling portion 32 and the electrode assembly 10 effectively reduces the internal resistance of the battery.

[0095] Meanwhile, as an embodiment for ensuring a large area of ​​the tab coupling portion 32, the case where the shape of the tab coupling portion 32 is approximately fan-shaped has been described as an example. However, the scope of the present invention is not limited to this, and any shape that can ensure a contact area between the tab coupling portion 32 and the electrode assembly 10 of a certain level or more is included in the scope of the present invention.

[0096] According to an embodiment of the present invention, the support portion 31 and the tab connecting portion 32 are disposed on the upper portion of the electrode assembly 10. The tab connecting portion 32 may be connected to the first non-coated portion 11 of the electrode assembly 10. For example, the tab connecting portion 32 may be connected to the first non-coated portion 11 by welding along the radial direction of the electrode assembly 10. For example, the tab connecting portion 32 may be connected to the first non-coated portion 11 by welding while being substantially parallel to the lower surface of the battery housing 20. A weld bead may be formed between the first non-coated portion 11 and the tab connecting portion 32. The weld bead may form, for example, a substantially linear weld pattern extending along the radial direction of the electrode assembly 10. The weld pattern may be, for example, a line formed by connecting weld points. The weld pattern may include one pattern or two or more patterns extending along the radial direction of the electrode assembly 10.

[0097] For example, the weld pattern may be configured to be approximately perpendicular to the notch line NL. Alternatively, as described above, the weld pattern may have an approximately linear shape extending radially from the center of the current collector 30. In this case, the notch line NL may be configured to be curved with a curvature that bulges toward the center of the current collector 30. Here, a tangent to the notch line NL at a point where the distance from the weld pattern to the notch line NL is shortest may be configured to be approximately perpendicular to the weld pattern. That is, the weld pattern and the notch line NL may be configured to be approximately perpendicular to each other.

[0098] This structure ensures ease of welding during the process. Also, this structure allows a welding pattern to be formed along the radial direction of the electrode assembly 10, thereby allowing current to flow uniformly from the electrode assembly 10. Furthermore, this structure shortens the current path, effectively reducing the internal resistance of the battery.

[0099] 4 to 9 according to an embodiment of the present invention, the tab coupling portion 32 and the housing coupling portion 33 are indirectly connected to each other via the support portion 31, and are not directly connected to each other. This minimizes the possibility of damage occurring at the coupling portion between the current collector 30 and the electrode assembly 10 and the coupling portion between the current collector 30 and the battery housing 20 when an external impact is applied to the battery cell 1 of the present invention.

[0100] 4 to 9, according to an embodiment of the present invention, at least one tab coupling portion 32 and / or one housing coupling portion 33 may be provided. The at least one tab coupling portion 32 and the at least one housing coupling portion 33 may be arranged, for example, in a substantially radial, cross, or combination thereof, based on the center of the current collector 30. In another aspect, each of the plurality of housing coupling portions 33 may be arranged between adjacent tab coupling portions 32.

[0101] 3 and 4 , according to an embodiment of the present invention, the support portion 31 and the plurality of tab coupling portions 32 are disposed on the upper portion of the electrode assembly 10. For example, the tab coupling portion 32 is coupled to the first non-coated portion 11 of the electrode assembly 10. The tab coupling portion 32 may be coupled to the first non-coated portion 11 by welding along the radial direction of the electrode assembly 10. The tab coupling portion 32 may be coupled to the first non-coated portion 11 by welding, for example, in a state substantially parallel to the lower surface of the battery housing 20. The welds formed between the first non-coated portion 11 and the tab coupling portions 32 may form a substantially linear weld pattern extending along the radial direction of the electrode assembly 10, for example.

[0102] According to an embodiment of the present invention, not only the tab coupling portion 32 but also the support portion 31 may be coupled to the first non-coating portion 11. The tab coupling portion 32 and the first non-coating portion 11 may be coupled by welding. When a beading portion 21 is formed on the battery housing 20, the support portion 31 and the tab coupling portion 32 are located below the beading portion 21.

[0103] For example, the support part 31 may have a current collector hole H2 formed at a position corresponding to a winding hole H1 formed at approximately the center of the electrode assembly 10. The winding hole H1 and the current collector hole H2, which are connected to each other, may function as a passage for inserting a welding rod or irradiating a laser beam for welding the terminal 50 to the current collector 30 or the terminal to a lead tab (not shown). The current collector hole H2 may have a diameter substantially the same as or larger than the winding hole H1 of the electrode assembly 10 so as not to obstruct the winding hole H1 formed in the core of the electrode assembly 10. If the diameter of the current collector hole H2 is too small compared to the diameter of the winding hole H1, the hole may be obstructed, reducing the ability to inject liquid. Furthermore, the diameters of the current collector hole H2 and the winding hole H1 may be appropriately adjusted, taking into consideration that sufficient space may not be secured for inserting a welding device or for irradiating a laser.

[0104] The plurality of tab connection portions 32 according to one embodiment of the present invention may have a configuration that extends substantially radially from the support portion 31 of the current collector 30 toward the side wall of the battery housing 20. The plurality of tab connection portions 32 may be positioned spaced apart from one another along the circumference of the support portion 31.

[0105] According to an embodiment of the present invention, the plurality of housing coupling portions 33 may extend radially from the support portion 31 of the current collector 30 toward the sidewall of the battery housing 20. The plurality of housing coupling portions 33 may be spaced apart from one another along the circumference of the support portion 31. At least one housing coupling portion 33 may be located between adjacent tab coupling portions 32.

[0106] For example, the housing coupling portion 33 may extend from the support portion 31 and be electrically coupled to the inner surface of the battery housing 20. For example, the housing coupling portion 33 may be coupled to, for example, a beading portion 21 on the inner surface of the battery housing 20. In particular, the housing coupling portion 33 may be coupled to the upper surface of the beading portion 21.

[0107] Alternatively, the housing coupling portion 33 may include a contact portion that couples with the inner surface of the battery housing 20 and a connecting portion that connects between the support portion 31 and the contact portion.

[0108] According to an embodiment of the present invention, the contact portion is coupled to the inner surface of the battery housing 20. When a beading portion 21 is formed on the battery housing 20, the contact portion may be coupled to the beading portion 21. In this case, for stable contact and coupling, both the beading portion 21 and the contact portion may have a shape that extends in a direction substantially parallel to the bottom surface of the battery housing 20, i.e., in a direction substantially perpendicular to the side wall of the battery housing 20.

[0109] According to an embodiment of the present invention, the contact portion may be joined to the upper surface of the beading portion 21 by welding. That is, the weld may be formed in the upper surface region of the beading portion 21. The weld formed between the contact portion and the beading portion 21 may be narrower than the upper surface of the beading portion 21. For example, laser welding, ultrasonic welding, spot welding, or the like may be used as welding for joining the battery housing 20 and the current collector 30.

[0110] FIG. 10 is a diagram for explaining a case where thermal runaway occurs in a battery cell 1 to which a conventional current collector 30 is applied.

[0111] The conventional battery cell 1 shown in Fig. 10 includes a current collector 30, which does not include any holes other than a centrally located current collector hole H2. Due to the structure of the conventional current collector 30, a flame generated in the electrode assembly 10 is blocked by the current collector 30 and is not smoothly discharged. This can lead to a problem in which the flame moves toward the beading portion 21 located in the peripheral region of the electrode assembly 10 and the current collector 30, causing a pinhole in the beading portion 21. If a pinhole is formed in the beading portion 21, it is highly likely that other battery cells 1 located around the battery cell 1 where the fire occurred will be directly damaged, and ultimately, the fire will inevitably spread to the other battery cells 1.

[0112] FIG. 11 is a diagram illustrating a case where thermal runaway occurs in the battery cell 1 according to an embodiment of the present invention.

[0113] The battery cell 1 according to an embodiment of the present invention shown in FIG. 11 includes a current collector 30 having a fractured portion 34. The current collector 30 may have through-holes HC. With this structure, flames generated in the electrode assembly 10 can be discharged to the outside of the electrode assembly 10 through the through-holes HC. This prevents the flames from progressing toward the beading portion 21. As a result, according to the present invention, damage to the beading portion 21 due to the flame can be prevented. Alternatively, according to an embodiment of the present invention, the generation of pinholes in the beading portion 21 can be effectively prevented.

[0114] FIG. 12 is a diagram illustrating another case where thermal runaway occurs in a battery cell 1 according to one embodiment of the present invention, and FIG. 13 is a diagram illustrating yet another case where thermal runaway occurs in a battery cell 1 according to one embodiment of the present invention.

[0115] The current collector 30 shown in FIGS. 12 and 13 is similar to the current collector 30 of the above-described embodiment, and therefore, a redundant description of the configuration that is substantially the same as or similar to the above-described embodiment will be omitted, and the following description will focus on the differences from the above-described embodiment.

[0116] 12 , according to an embodiment of the present invention, a notch line NL including a plurality of notches may be formed in a boundary region between the support portion 31 and the tab coupling portion 32. With this structure, when vent gas generated due to thermal runaway or the like is ejected upward from the electrode assembly 10, the tab coupling portion 32 receives upward pressure from the vent gas, and the tab coupling portion 32 may be bent upward based on the notch line NL. When the tab coupling portion 32 is bent upward, flames generated in the electrode assembly 10 are smoothly exhausted through a space formed between the electrode assembly 10 and the tab coupling portion 32.

[0117] Figure 13, according to one embodiment of the present invention, illustrates a case in which vent gas is ejected more strongly than in Figure 12. In the embodiment of Figure 13, the tab connector 32 is subjected to upward pressure by the vent gas, which may cause the tab connector 32 to separate from the current collector 30 along the notch line NL and fall. As a result, the space formed by the separation of the tab connector 32 allows flames generated in the electrode assembly 10 to be smoothly exhausted.

[0118] As described above, in one embodiment of the present invention, the structure in which the through holes HC and / or notch lines NL are provided at the boundary between the support portion 31 and the tab coupling portion 32 allows flames generated in the electrode assembly 10 to be smoothly discharged to the outside. This prevents the flames from spreading to the beading portions 21 located near the sides of the electrode assembly 10 and the current collector 30. As a result, the structure of the present invention prevents damage such as pinholes from occurring in the beading portions 21.

[0119] 1 to 3 according to an embodiment of the present invention, the housing cover 40 may include a vent portion 41 formed to prevent an increase in internal pressure due to gas generated inside the battery housing 20. The vent portion 41 may be configured to rupture when the internal pressure of the battery housing 20 increases above a certain level. For example, the vent portion 41 may be formed in a portion of the housing cover 40 and may be a region structurally weaker than the surrounding region so as to be easily ruptured when internal pressure is applied. The vent portion 41 may be, for example, a region having a thickness thinner than the surrounding region. Referring to FIGS. 1 and 2, the vent portion 41 may form a substantially circular closed loop.

[0120] 1 to 3 , according to an embodiment of the present invention, the housing cover 40 covers the opening formed on one side of the battery housing 20. The housing cover 40 may be fixed by a crimping portion 22 formed on the upper end of the battery housing 20. In this case, to improve fixing strength and sealability of the battery housing 20, a sealing gasket G1 may be interposed between the battery housing 20 and the housing cover 40 and between the current collector 30 and the housing cover 40. In this case, the contact portion may be interposed between the beading portion 21 of the battery housing 20 and the sealing gasket G1. The contact portion interposed between the beading portion 21 and the sealing gasket G1 may be fixed by bending the crimping portion 22 extending upward from the beading portion 21.

[0121] A battery module according to an embodiment of the present invention includes a plurality of battery cells, each of which has a basic unit cell that smoothly exhausts a flame generated inside the battery cell when thermal runaway occurs, and includes a battery assembly in which the plurality of battery cells are electrically connected and a module housing that accommodates the battery assembly. Alternatively, the battery module may be used to supply power to an Energy Storage System (ESS).

[0122] FIG. 14 is a diagram illustrating a battery pack 3 including a battery cell 1 according to an embodiment of the present invention.

[0123] 14, a battery pack 3 according to an embodiment of the present invention includes a battery assembly in which a plurality of battery cells 1 according to an embodiment of the present invention are electrically connected as described above, and a pack housing 2 that accommodates the battery assembly. For ease of illustration, components such as bus bars for electrical connections, a cooling unit, and power terminals are omitted from the drawings of the present invention.

[0124] FIG. 15 is a diagram illustrating an automobile 5 including the battery pack 3 of FIG.

[0125] 15, an automobile 5 according to an embodiment of the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and includes a battery pack 3 according to an embodiment of the present invention. The automobile 5 includes a four-wheeled vehicle and a two-wheeled vehicle. The automobile 5 operates by receiving power from the battery pack 3 according to an embodiment of the present invention.

[0126] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is of course possible for a person skilled in the art to which the present invention pertains to make various modifications and variations within the technical spirit of the present invention and the equivalent scope of the following claims. [Explanation of symbols]

[0127] 1 battery cell 2-pack housing 3 Battery Pack 5. Automobiles 10 Electrode assembly 11 First non-coating section 12 Second non-coating section 20 Battery housing 21 Beading section 22 Crimping section 30 Current collector 31 Support part 32 Tab joint 33 Housing joint 34 Breaking part 40 Housing cover 41 Vent NL Notch Line HC through hole G1 sealing gasket

Claims

1. An electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, the first electrode including a first non-coated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side thereof and accommodating the electrode assembly through the opening; a current collector including: a support portion disposed on an upper portion of the electrode assembly; a tab connecting portion extending from the support portion and connecting to the first non-coated portion; and a housing connecting portion extending from the support portion and electrically connecting to an inner surface of the battery housing; Including, The battery cell, wherein a breaking portion having a lower strength than a surrounding area is provided at a boundary between the support portion and the tab connecting portion.

2. The battery cell according to claim 1 , wherein the fracture portion includes a notch line including a plurality of notches.

3. The battery cell of claim 2 , wherein the current collector includes a through hole configured to extend through the current collector.

4. The battery cell according to claim 3 , wherein the through-hole is located at the notch line.

5. The battery cell according to claim 3 or 4, wherein the through-hole is located at a center of a boundary between the support portion and the tab coupling portion.

6. The battery cell according to claim 3 or 4, wherein at least one through-hole is provided in the support portion.

7. The battery cell according to claim 3 or 4, wherein at least one through-hole is provided in the tab coupling portion.

8. The battery cell according to claim 2 , wherein the notch line has a curved shape.

9. The battery cell according to claim 1 , wherein the tab connection portion has a width greater than that of the housing connection portion.

10. The battery cell according to claim 2 , wherein the first non-coated portion and the tab connecting portion are connected by welding along a radial direction of the electrode assembly.

11. a weld bead is formed between the first non-coated portion and the tab connecting portion; The weld bead is The battery cell according to claim 10 , wherein a linear welding pattern extending along a radial direction of the electrode assembly is formed.

12. The battery cell according to claim 11 , wherein the welding pattern is configured to be perpendicular to the notch line.

13. a support portion disposed on an upper portion of the electrode assembly; a tab connection portion extending from the support portion and electrically connecting to the electrode assembly; and a housing connection portion extending from the support portion and electrically connecting to an inner surface of a battery housing in which the electrode assembly is accommodated, A current collector, characterized in that a breaking portion having a lower strength than a surrounding area is provided at the boundary between the support portion and the tab connecting portion.

14. A battery pack comprising at least one battery cell according to any one of claims 1 to 4.

15. A motor vehicle comprising at least one battery pack according to claim 14.

16. A battery module comprising at least one battery cell according to any one of claims 1 to 4.

17. An energy storage system comprising at least one battery module according to claim 16.

18. An electrode assembly having a core and an outer circumferential surface defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, wherein the first electrode includes a first non-coated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side thereof and accommodating the electrode assembly through the opening; a current collector including: a support portion disposed on an upper portion of the electrode assembly; a tab connecting portion extending from the support portion and connecting to the first non-coated portion; and a housing connecting portion extending from the support portion and electrically connecting to an inner surface of the battery housing; Including, The battery cell, wherein the current collector has a passage formed therein that allows a flame to be discharged to the outside when a thermal runaway occurs in the electrode assembly.

19. The battery cell according to claim 18 , wherein the passage includes a break portion at a boundary between the support portion and the tab connection portion, the break portion having a lower strength than a surrounding area.

20. The battery cell of claim 19 , wherein the fracture portion comprises a notch line including a plurality of notches.

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