Cylindrical battery cell

Abstract

The present invention provides a cylindrical battery cell. The cylindrical battery cell of the present invention comprises: a can housing having an opening formed in one side thereof; an electrode assembly accommodated in the can housing; a current collecting plate disposed at the end portion of the electrode assembly in the axial direction; and a vent plate which is disposed on the outer side of the current collecting plate in the axial direction, covers the opening of the can housing, and has a vent notch formed therein, wherein the current collecting plate comprises: a support ring portion which is disposed at the end portion of the electrode assembly in the axial direction, and has formed therein a support hole portion so as to correspond to a core unit of the electrode assembly; a plurality of support ribs which extend outwardly from the support ring portion in the radial direction, and are bonded to the end portion of the electrode assembly in the axial direction; and a plurality of bridge portions which extend outwardly from the support ring portion in the radial direction, are electrically connected to the can housing, and have bridge notch portions formed therein.

Description

cylindrical battery cells

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0108661, dated August 13, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a cylindrical battery cell that can easily discharge loose parts or fragments of an electrode assembly when a thermal runaway occurs and prevent combustion or fire from spreading to surrounding battery cells.

[0003] Typically, a cylindrical battery cell comprises a can housing and an electrode assembly. The can housing is manufactured by deep-drawing a metal sheet to form a circular bottom portion and a circular tubular side wall portion connected to the bottom portion.

[0004] Cylindrical battery cells house an electrode assembly within a can housing. The electrode assembly is wound into a cylinder with a synthetic resin separator interposed between the negative and positive electrodes. The bottom of the can housing may be welded to the negative electrode collector plate, and the vent may be welded to the positive electrode collector plate.

[0005] Recently, a cylindrical battery cell with a new structure is being developed. The cylindrical battery cell may include a beaded crimping area with a vent and a rivet area containing a positive terminal. A vent plate with a vent may be installed in the beaded crimping area, and a rivet terminal may be installed in the rivet area. An insulating gasket is placed between the rivet terminal and the terminal hole in the can housing.

[0006] On both axial sides of the electrode assembly, a flat surface is formed by pressing and laying down the electrode tab portion. A negative electrode collector plate may be welded to the flat surface on both axial sides of the electrode assembly, and a positive electrode collector plate may be welded to the flat surface on the other axial side of the electrode assembly. In addition, the negative electrode collector plate may be welded to the crimping portion of the can housing, and the positive electrode collector plate may be welded to the rivet terminal portion.

[0007] A vent plate is arranged on the outside of the negative electrode collector, and the periphery of the vent plate and the periphery of the negative electrode collector are crimped and fixed by a crimping portion. A vent notch is formed in the vent plate. When thermal runaway occurs inside the can housing, the vent notch may be cut or broken as gas pressure is applied to the vent plate. As the vent notch is cut or broken, combustion products and gases of the electrode assembly are discharged to the outside.

[0008] However, since the negative current collector is conventionally installed to completely block one axial flat surface of the electrode assembly, when thermal runaway occurs, the electrode assembly is blocked by the negative current collector, making it difficult for any loose parts of the electrode assembly in the axial direction to be discharged outside the can housing. In addition, when thermal runaway occurs, combustion fragments of the electrode assembly may be generated, but these fragments are also blocked by the negative current collector, making it difficult for them to be discharged outside the can housing. In this way, since it is difficult for loose parts or fragments of the electrode assembly to be discharged outside the can housing, most of the electrode assembly may remain inside the can housing. Accordingly, the residual amount of the electrode assembly, which provides a cause of combustion or explosion, increases, which may prolong the thermal runaway time in the battery cell. As the thermal runaway time in the battery cell prolongs, flames or thermal runaway may spread to surrounding battery cells installed in the battery pack.

[0009] The present invention has been devised to solve the above-described problem, and aims to provide a cylindrical battery cell capable of easily discharging loose parts or fragments of an electrode assembly when thermal runaway occurs.

[0010] The present invention aims to provide a cylindrical battery cell in which the residual amount of an electrode assembly inside a can housing can be rapidly reduced.

[0011] The purpose of the present invention is to provide a cylindrical battery cell capable of preventing combustion or fire from spreading to surrounding battery cells when thermal runaway occurs.

[0012] The technical objectives of the present invention are not limited to the purposes mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0013] The present invention can be applied to a battery cell including a can housing having an opening formed on one side, an electrode assembly accommodated inside the can housing, a current collector plate disposed at an axial end of the electrode assembly, and a vent plate disposed on an axial outer side of the current collector plate and covering the opening of the can housing.

[0014] The above battery cell may be cylindrical. However, the present invention is not limited to cylindrical battery cells.

[0015] The above vent plate is formed with a vent notch portion. The above vent notch portion may be defined by a notch groove formed in the thickness direction on one or both surfaces of the vent plate.

[0016] The above vent notch portion may be formed to extend in a circumferential direction along the edge of the vent plate from the inside.

[0017] The above-mentioned vent notch portion may form a closed loop or may form a substantially closed loop. For example, the above-mentioned vent notch portion may be in the form of a continuously extended notch groove or in the form of an intermittently extended notch groove.

[0018] In some examples, the vent notch portion may be circular.

[0019] The above collector plate may include a portion extending in the circumferential direction and a portion extending in the radial direction. In some examples, the collector plate may further include a portion extending in the axial direction by a bending portion.

[0020] Preferably, the current collector plate may include a support ring portion formed with a support hole portion corresponding to a core portion of the electrode assembly and disposed at an axial end of the electrode assembly, a plurality of support ribs extending radially outward from the support ring portion and joined to the axial end of the electrode assembly, and a plurality of bridge portions extending radially outward from the support ring portion and electrically connected to the can housing.

[0021] The above support ring portion may be extended in a circumferential direction to surround the support hole portion. Preferably, the support hole portion may be in a closed loop shape.

[0022] The above plurality of support ribs can be arranged radially along the circumference of the support ring portion.

[0023] The plurality of support ribs extending radially outward from the edge of the support ring portion may be spaced apart from each other along the circumferential direction of the support ring portion.

[0024] The plurality of bridge portions extending radially outward from the edge of the support ring portion may be spaced apart from each other along the circumferential direction of the support ring portion.

[0025] The above plurality of support ribs and the above plurality of bridge parts can be arranged alternately along the circumferential direction.

[0026] The plurality of bridge portions may be radially arranged between the plurality of support ribs.

[0027] The connecting portions of the plurality of bridge portions and the support ring portion can be bent. Accordingly, the plurality of bridge portions can also extend in the axial direction.

[0028] The above bridge portion may have a leg portion extending radially from the periphery of the support ring portion, and a leg mounting portion extending from the leg portion and joined to the can housing.

[0029] The above leg portion may extend radially from the support ring portion and thus be inclined axially.

[0030] Preferably, the number of bridge sections and the number of support ribs may correspond. For example, four of each may be provided. However, the number of these is not limited to this.

[0031] The above support rib can be electrically connected by being joined to an electrode tab provided at an axial end of the electrode assembly. For example, the joining can be achieved by welding.

[0032] The above leg mounting portion may be electrically connected to the can by being joined. For example, the joining may be accomplished by welding.

[0033] The above leg mounting portion can be joined to the beading groove portion of the can.

[0034] The present invention proposes an embodiment in which a plurality of plate notches are formed on the current collector plate as a solution to the above-described technical problem.

[0035] The above-described plurality of plate notches may be formed in a form that divides the collector plate into two or more parts. For example, the plate notches may be formed so as to be breakable in a direction transverse to the direction in which each part of the collector plate extends. When the plate notches are broken, the portion extending from the collector plate may be cut off by the broken portion of the plate notches.

[0036] The plurality of plate notches may include bridge notches formed in the bridge portion. Preferably, the bridge notches may be formed in each of the plurality of bridge portions.

[0037] The above bridge notch portion can be formed so that its fracture occurs along a width direction intersecting the extension direction of the bridge portion.

[0038] In some examples, the bridge notch portion may be defined by a portion where the width of the bridge is narrowed by bridge notch grooves formed on both sides of the width direction of the bridge portion.

[0039] In some examples, the bridge notch portion may be defined by a notch groove formed on the surface of the bridge portion and extending transversely along the extension direction of the bridge portion. The bridge notch portion may be in the form of a continuous or interrupted line extending across the width direction of the bridge portion. Preferably, the line shape may be a straight line.

[0040] When the bridge notch portion of the above bridge portion is broken, the bridge portion can be separated from the support ring portion.

[0041] The above plurality of plate notches may include a ring notching portion formed in the support ring portion.

[0042] In some examples, the ring notch portion may be formed in multiple numbers in the support ring portion.

[0043] Preferably, a plurality of ring notches may be spaced apart along the circumferential direction of the ring notches.

[0044] Preferably, the number of the ring notches may correspond to the number of the support ribs.

[0045] Preferably, the number of the ring notch portions may correspond to the number of the bridge portions.

[0046] The above ring notch portion can be formed so that its breakage occurs along a radial direction intersecting the extension direction of the support ring portion.

[0047] In some examples, the ring notch portion may be defined by a portion where the width of the ring is narrowed by notch grooves formed on the radially outer and inner sides of the support ring portion, respectively.

[0048] In some examples, the ring notch portion may be defined by a notch groove formed on the surface of the support ring portion and extending transversely along the extension direction of the support ring portion. The ring notch portion may be in the form of a continuous or interrupted line radially extending across the support ring portion. Preferably, the line shape may be a straight line.

[0049] Preferably, the ring notch portion may be provided in a portion that does not overlap the bridge portion and the support rib in the circumferential direction.

[0050] Preferably, the ring notch portion may be provided between the plurality of bridge portions and the plurality of support ribs in the circumferential direction.

[0051] If the ring notch portion of the above support ring portion is broken, the closed loop shape of the above support ring portion may be broken at the broken portion.

[0052] The above plurality of plate notches may be arranged on the inner side of the axial projection surface of the above vent notch.

[0053] The above bridge notch portion may be arranged on the inner side of the axial projection surface of the above vent notch portion.

[0054] The above-mentioned vent notch portion may be formed in a circular shape concentric with the support ring portion, and the above-mentioned bridge notch portion may be arranged along the circumferential direction to be concentric with the support ring portion.

[0055] The above bridge notch portion may be a bridge notch groove formed on both sides of the width direction of the bridge portion.

[0056] The above bridge notch portion can be formed in a straight line shape so as to cross the width direction of the bridge portion.

[0057] The above bridge notch portion can be formed at the boundary between the support ring portion and the bridge portion.

[0058] The above bridge notch portion may be formed at a portion spaced a certain distance radially outward from the boundary between the support ring portion and the bridge portion.

[0059] The above bridge notch portion can be formed in the above leg portion.

[0060] At least one ring notch portion may be formed in the above support ring portion.

[0061] The above ring notch portion can be placed on the inner side of the axial projection surface of the above vent notch portion.

[0062] The above ring notch portion can be formed between the support rib and the bridge portion in the support ring portion.

[0063] The above ring notch portion can be formed in a straight line shape parallel to the radial direction of the support ring portion.

[0064] The above ring notch portion divides the support ring portion into two or more sections, so that when thermal runaway occurs, the closed-loop support ring portion can be divided into two or more sections and ejected, thereby preventing the support ring portion from blocking the vent outlet.

[0065] In some examples, at least one bridge portion or at least one support rib may be connected to a section between two circumferentially adjacent ring notches in the support ring portion. Accordingly, when a thermal runaway occurs, when the section of the support ring portion divided by the ring notches receives a discharge power from the electrode assembly, a portion of the bridge portion or the support rib connected thereto may also receive the discharge power and be discharged.

[0066] Preferably, at least one bridge portion and at least one support rib may be connected to a section between two circumferentially adjacent ring notches in the support ring portion. Accordingly, when a thermal runaway occurs, when the section where the support ring portion is divided by the ring notch portion receives a discharge power from the electrode assembly, a portion of the bridge portion and the support rib connected thereto may receive the discharge power together and be discharged.

[0067] The above bridge notch portion induces the breakage of the bridge portion joined to the can when the support ring portion receives the spraying force, so that the above-described spraying can be performed more smoothly.

[0068] In some examples, the ring notch portion may be formed in a manner that blocks the support ring portion connecting the adjacent bridge portion and the support rib. For example, if the bridge portion and the support rib each have four, the ring notch portion may be provided in eight pieces. Accordingly, if the ring notch portion is broken, the electrical connection between the bridge portion and the support rib may be severed.

[0069] The outer ends of the plurality of support ribs may be positioned radially outside the projection surface. Accordingly, the joint area of ​​the support ribs can be further expanded. Even if the outer ends of the support ribs are positioned outside the projection surface, since the support ring portion is divided by the ring notch portion, the support ribs can be smoothly discharged together with the divided support ribs connected thereto.

[0070] According to the present invention, when a battery cell experiences thermal runaway, the welding portion and the bridge notch portion of the current collector plate are gradually torn or broken, thereby separating the support ring portion from the end of the electrode assembly, so that the separated support ring portion can smoothly pass through the broken opening of the vent plate due to internal pressure and be discharged to the outside.

[0071] According to the present invention, before the support ring portion is torn off and separated from the end portion of the electrode assembly, fragments generated from the electrode assembly can smoothly pass through the fracture opening of the vent plate via the periphery of the end portion of the electrode assembly.

[0072] According to the present invention, since loose parts or fragments of the electrode assembly in a battery cell in which thermal runaway has occurred are smoothly discharged to the outside of the can housing, the residual amount of the electrode assembly that causes combustion or explosion inside the can housing can be further reduced.

[0073] According to the present invention, the residual amount of the electrode assembly inside the can housing is quickly reduced, so that the thermal runaway time can be significantly shortened.

[0074] According to the present invention, since the residual amount of the electrode assembly inside the can housing is quickly reduced, the spread of flame or thermal runaway to the surrounding battery cells can be prevented.

[0075] According to the present invention, since a plurality of notches are formed in the collector plate, the collector plate can be separated into multiple pieces and partially cut or broken. Accordingly, small-sized collector plate pieces can be smoothly discharged through the break openings in the vent plate.

[0076] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0077] Figure 1 is an exploded perspective view schematically illustrating the stacking state of electrodes and separators constituting a battery cell according to the present invention.

[0078] Fig. 2 is a perspective view schematically illustrating the stacking state of the electrode and separator of Fig. 1.

[0079] Figure 3 is a perspective view schematically illustrating a cylindrical electrode assembly according to the present invention.

[0080] Fig. 4 is a perspective view schematically illustrating a state in which a positive electrode collector plate is welded to the cylindrical electrode assembly of Fig. 3.

[0081] Figure 5 is a perspective view schematically illustrating a state in which a negative electrode collector plate is welded to the cylindrical electrode assembly of Figure 3.

[0082] Figure 6 is a cross-sectional view schematically illustrating a can housing according to the present invention.

[0083] Figure 7 is a cross-sectional view schematically illustrating a state in which an electrode assembly according to the present invention is inserted into a can housing.

[0084] Fig. 8 is a cross-sectional view schematically illustrating a state in which a beading groove is formed near the opening of a can housing according to the present invention.

[0085] Figure 9 is a perspective view schematically illustrating a state in which a bridge portion of a negative electrode collector plate is seated in a beading groove portion of a can housing according to the present invention.

[0086] Fig. 10 is a cross-sectional view schematically illustrating a state in which a crimping portion is formed in a can housing according to the present invention and a vent plate and a crimping gasket are compressed.

[0087] Fig. 11 is an enlarged view schematically illustrating a state in which a crimping portion is formed in a can housing according to the present invention and a vent plate and a crimping gasket are compressed.

[0088] Figure 12 is an exploded perspective view schematically illustrating the corresponding relationship between the vent plate and the negative electrode collector plate according to the present invention.

[0089] Fig. 13 is a plan view schematically illustrating a state in which the bridge notch portion of the negative electrode collector plate of Fig. 12 is positioned on the inner side of the projection surface of the vent notch portion of the vent plate.

[0090] Figure 14 is a plan view schematically illustrating a first embodiment of a negative electrode collector plate according to the present invention.

[0091] Fig. 15 is a cross-sectional view schematically illustrating the negative electrode collector plate of Fig. 14.

[0092] Fig. 16 is an enlarged view schematically illustrating the structure of the bridge notch portion of the negative electrode collector plate of Fig. 14.

[0093] Figure 17 is a plan view schematically illustrating a second embodiment of a negative electrode collector plate according to the present invention.

[0094] Fig. 18 is an enlarged view schematically illustrating the structure of the bridge notch portion of the negative electrode collector plate of Fig. 17.

[0095] Figure 19 is a plan view schematically illustrating a third embodiment of a negative electrode collector plate according to the present invention.

[0096] Figure 20 is a plan view schematically illustrating a fourth embodiment of a negative electrode collector plate according to the present invention.

[0097] Figure 21 is a cross-sectional view schematically illustrating a state in which pressure is applied to a vent plate when thermal runaway occurs in a battery cell according to the present invention.

[0098] Figure 22 is a cross-sectional view schematically illustrating a state in which the center portion is separated due to the breakage of the vent notch portion of the vent plate when thermal runaway occurs in a battery cell according to the present invention.

[0099] Figure 23 is a cross-sectional view schematically illustrating a state in which most of the electrode assembly is discharged to the outside through a fracture opening of a vent plate when a thermal runaway occurs in a battery cell according to the present invention.

[0100] [Explanation of symbols]

[0101] 10: Can housing 11: Side wall 12: Bottom 16: Beading groove 17: Crimping 20: Electrode assembly 21: First electrode 22: Second electrode 23: Metal foil 24: Active material layer 25: Coating 26: Uncoated 27: Electrode tab 28: Separator 29: Core 30: Positive current collector 31: Ring plate 32: Cross 33: Elastic 37: Insulator 40: Positive terminal 42: Terminal gasket 50: Negative current collector 51: Support 52: Support ring 52a: Support hole 53: Support rib 55: Bridge 56: Leg 57: Leg mounting 58, 58a: Bridge notch 59: Ring notch 60: Crimping Gasket 70: Vent plate 71: Plate body 72: Center part 73: Rim part 74: Vent notch part 74a: Projection surface

[0102] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0103] The present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and with various modifications. However, these embodiments are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. Therefore, the present invention is not limited to the embodiments disclosed below, but should be understood to include all modifications, equivalents, and substitutes included within the technical spirit and scope of the present invention, as well as substitutions or additions of the components of one embodiment with those of another embodiment.

[0104] The attached drawings are merely intended to facilitate understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification, but should be understood to encompass all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention. In the drawings, the components may be expressed in exaggerated sizes or thicknesses for ease of understanding, but the scope of protection of the present invention should not be construed as being limited thereby.

[0105] The terminology used in this specification is only used to describe specific implementations or examples and is not intended to limit the present invention. In addition, the singular expression includes the plural expression unless the context clearly indicates otherwise. In the specification, terms such as "comprises" and "consists of" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification. In other words, it should be understood that terms such as "comprises" and "consists of" in the specification do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0106] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0107] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0108] When a component is referred to as being "above" or "below" another component, it should be understood that it is not only positioned directly above that other component, but that there may also be other components present in between.

[0109] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0110] Hereinafter, a battery cell according to an embodiment of the present invention will be described.

[0111] FIG. 1 is an exploded perspective view schematically illustrating the laminated state of electrodes and separators constituting a battery cell according to the present invention, FIG. 2 is a perspective view schematically illustrating the laminated state of electrodes and separators of FIG. 1, and FIG. 3 is a perspective view schematically illustrating a cylindrical electrode assembly according to the present invention.

[0112] Referring to FIGS. 1 to 3, a battery cell according to an embodiment of the present invention includes an electrode assembly (20).

[0113] The electrode assembly (20) includes a first electrode (21), a second electrode (22), and a separator (28) that extend in the longitudinal direction and have a predetermined width as illustrated in FIG. 1. The electrode assembly (20) forms an electrode laminate in the order of the first electrode (21), the separator (28), the second electrode (22), and the separator (28) as illustrated in FIG. 2, and winds this around a core shaft to produce a jelly-roll shape as illustrated in FIG. 3. The electrode assembly (20) is formed in a cylindrical shape, and a core portion (29), which is an empty space, is formed in the center thereof.

[0114] The above first electrode (21) may be an anode, and the above second electrode (22) may be a cathode. Of course, the opposite may also be the case.

[0115] The above first electrode (21) and second electrode (22) are manufactured in the form of sheets. The electrodes (21, 22) are manufactured in the form in which an active material layer (24) is applied to the surface of a metal foil (23). The electrodes (21, 22) have a coated portion (25) on which the active material layer (24) is applied, and an uncoated portion (26) on which the active material layer (24) is not applied. The positive electrode may have an uncoated positive electrode portion on one side in the width direction, and the negative electrode may have an uncoated negative electrode portion on the other side in the width direction.

[0116] The uncoated portion (26) is exposed or protrudes in the width direction from the electrode laminate. The uncoated portion (26) itself can function as an electrode tab (27).

[0117] In the above-mentioned uncoated portion (26), tab grooves can be formed at predetermined intervals to form flag-shaped electrode tabs (27). A plurality of electrode tabs (27) can be arranged in a sawtooth shape along the longitudinal direction of the electrodes (21, 22).

[0118] In the embodiment, the electrode tabs (27) are exemplified as having an equilateral trapezoidal shape. However, their shapes may be various, such as a semicircle, a semi-ellipse, a triangle, a rectangle, or a parallelogram.

[0119] In addition, in the embodiment, a form in which electrode tabs (27) arranged along the longitudinal direction have the same width is exemplified. However, the width of the electrode tabs (27) may be gradually or stepwise widened from the core side to the outer circumference side.

[0120] In addition, in the embodiment, a form in which the height of the electrode tabs (27) gradually increases from the core side to the outer circumference side is exemplified. However, the height of these electrode tabs (27) may be implemented in a form in which they are constant or gradually decrease.

[0121] In addition, in the embodiment, a structure in which the electrode tab (27) is deleted in a predetermined section of the centripetal end of the uncoated portion (26) and a predetermined section of the centrifugal end is exemplified. However, it is of course possible that the electrode tab (27) is not deleted in the centripetal end of the uncoated portion (26), and that the electrode tab (27) is not deleted in the centrifugal end of the uncoated portion (26).

[0122] In the jelly roll-shaped electrode assembly (20), the electrode tabs (27) can be bent radially and flattened as illustrated in FIG. 3. The electrode tabs (27) can be bent radially inward or outward. In the embodiment, a structure in which the electrode tabs (27) are bent radially inward is exemplified.

[0123] The above electrode tabs (27) can be bent one by one during the process of forming a jelly roll-shaped electrode assembly (20) by winding the laminate. Alternatively, the electrode tabs (27) can be bent all at once after forming a jelly roll-shaped electrode assembly (20) by winding the laminate.

[0124] The electrode tabs (27) of the first electrode (21) and the electrode tabs (27) of the second electrode (22), which are bent and overlapped in the radial direction in this way, can provide a plane that is substantially perpendicular to the axial direction at each of the axial ends of the electrode assembly (20).

[0125] Fig. 4 is a perspective view schematically illustrating a state in which a positive electrode collector plate is welded to the cylindrical electrode assembly of Fig. 3, and Fig. 5 is a perspective view schematically illustrating a state in which a negative electrode collector plate is welded to the cylindrical electrode assembly of Fig. 3.

[0126] Referring to FIGS. 4 and 5, a flat surface is formed at each of the axial ends of the electrode assembly (20) as the electrode tabs (27) are bent. A positive electrode collector plate (30) may be joined to one axial end of the electrode assembly (20), and a negative electrode collector plate (50) may be joined to the other axial end of the electrode assembly (20).

[0127] The above positive electrode collector plate (30) may be made of aluminum, and the above negative electrode collector plate (50)(30) may be made of copper. However, the materials are not limited thereto.

[0128] The positive electrode collector plate (30) includes a ring plate (31) arranged along the axial end of the electrode assembly (20), a cross portion (32) crossing the inside of the ring plate (31), and an elastic portion (33) extending radially inward from the ring plate (31) (see FIG. 4). The cross portion (32) may be installed to cover the core portion (29) of the electrode assembly (20). A portion (center portion) of the cross portion (32) that covers the core portion (29) of the electrode assembly (20) may be welded to the positive electrode terminal portion (40). In addition, the elastic portion (33) is welded to a positive electrode tab (27) bent in a flat shape on one axial end of the electrode assembly (20). This positive electrode collector plate (30) may electrically connect the positive electrode tab (27) and the positive electrode terminal portion (40).

[0129] The negative electrode collector plate (50) includes a support portion (51) arranged to surround the core portion (29) at the axial end of the electrode assembly (20), and a bridge portion (55) extending radially from the support portion (51) (see FIG. 5). The support portion (51) can be welded to the negative electrode tab (27) laid flat on the axial end of the electrode assembly (20). The bridge portion (55) can be welded to the beading groove portion (16). The end of the bridge portion (55) and the periphery of the vent plate (70) are press-fitted and fixed to the beading groove portion (16) and the crimping portion (17) (see FIG. 10).

[0130] The positive electrode collector plate (30) and the negative electrode collector plate (50) can be manufactured by punching, trimming, piercing, and banding a metal sheet.

[0131] FIG. 6 is a cross-sectional view schematically illustrating a can housing according to the present invention, FIG. 7 is a cross-sectional view schematically illustrating a state in which an electrode assembly according to the present invention is inserted into a can housing, FIG. 8 is a cross-sectional view schematically illustrating a state in which a beading groove portion is formed near an opening portion of a can housing according to the present invention, FIG. 9 is a perspective view schematically illustrating a state in which a bridge portion of a negative electrode current collector plate is seated in a beading groove portion of a can housing according to the present invention, and FIG. 10 is a cross-sectional view schematically illustrating a state in which a crimping portion is formed in a can housing according to the present invention and a vent plate and a crimping gasket are compressed.

[0132] Referring to FIGS. 6 to 10, the can housing (10) includes a cylindrical side wall portion (11) and a bottom portion (12) that closes one side of the side wall portion (11). An opening portion is formed on the other side of the side wall portion (11). A terminal hole (not shown) is formed in the center of the bottom portion (12).

[0133] A positive terminal portion (40) is installed in a terminal hole (not shown) of a can housing (10). A terminal gasket (42) is interposed around the periphery of the positive terminal portion (40) to electrically insulate the positive terminal portion (40) from the can housing (10). The can housing (10) is positioned so that the opening faces downward.

[0134] An insulator (40) is laminated on the inner surface of the bottom portion (12) of the can housing (10). An electrode assembly (20) is inserted into the can housing (10). The can housing (10) with the electrode assembly (20) inserted is turned upside down. At this time, the positive electrode collector plate (30) welded to the electrode assembly (20) is pressed against the positive electrode terminal portion (40) by the weight of the electrode assembly (20). The upper welding rod contacts the positive electrode collector plate (30) and the positive electrode terminal portion (40) through the core portion (29) of the electrode assembly (20), and the lower welding rod contacts the lower side of the positive electrode terminal portion (40). The upper welding rod and the lower welding rod weld the positive electrode collector plate (30) and the positive electrode terminal portion (40). When welding is completed, the upper welding rod and the lower welding rod are removed.

[0135] A beading device (not shown) forms a beading groove (16) on the opening side of the can housing (10) (see FIGS. 8 and 9). The beading groove (16) is recessed in an arc shape along the circumference of the can housing (10) to axially restrain the electrode assembly (20). A bridge portion (55) of a negative electrode collector (50) is mounted on the upper side of the beading groove (16). A leg mounting portion (57) of the bridge portion (55) can be welded to the upper side of the beading groove (16).

[0136] With the bridge portion (55) welded to the upper side of the beading groove portion (16), the crimping gasket (60) is placed on the upper side of the bridge portion (55), and the circumference of the vent plate (70) and the crimping gasket (60) are placed on the upper side of the bridge portion (55). At this time, the circumference of the vent plate (70) is inserted into the inside of the crimping gasket (60). A crimping device (not shown) bends the opening of the can housing (10) inward to press and fix the crimping gasket (60), the circumference of the vent plate (70), and the bridge portion (55) of the negative electrode collector (50). At this time, the crimping portion (17) seals by pressing and fixing the circumference of the crimping gasket (60) and the vent plate (70).

[0137] FIG. 11 is an enlarged view schematically illustrating a state in which a crimping portion is formed in a can housing according to the present invention and a vent plate and a crimping gasket are compressed, FIG. 12 is an exploded perspective view schematically illustrating a correspondence between a vent plate and a negative electrode collector plate according to the present invention, FIG. 13 is a plan view schematically illustrating a state in which a bridge notch portion of the negative electrode collector plate of FIG. 12 is arranged on the inner side of a projection surface of a vent notch portion of the vent plate, FIG. 14 is a plan view schematically illustrating a first embodiment of a negative electrode collector plate according to the present invention, FIG. 15 is a cross-sectional view schematically illustrating a negative electrode collector plate of FIG. 14, FIG. 16 is an enlarged view schematically illustrating a structure of a bridge notch portion of the negative electrode collector plate of FIG. 14, and FIG. 17 is a plan view schematically illustrating a second embodiment of a negative electrode collector plate according to the present invention, and FIG. 18 is a plan view schematically illustrating a bridge notch portion in the negative electrode collector plate of FIG. 17. This is an enlarged view schematically illustrating the structure, FIG. 19 is a plan view schematically illustrating a third embodiment of a negative electrode collector plate according to the present invention, and FIG. 20 is a plan view schematically illustrating a fourth embodiment of a negative electrode collector plate according to the present invention.

[0138] Referring to FIGS. 11 to 20, a negative electrode collector plate (50) and a vent plate (70) are arranged in the opening of the can housing (10). The negative electrode collector plate (50) is joined to the axial end of the electrode assembly (20), and a vent plate (70) is arranged on the axial outer side of the negative electrode collector plate (50).

[0139] The material of the negative electrode collector plate (50) may be formed of a material that can be welded to the electrode tab (27) and the can housing (10). The negative electrode collector plate may be a material with good electrical conductivity, such as copper, copper alloy, aluminum, or aluminum alloy. The vent plate (70) may be made of, for example, NPS (nickel plated steel) or aluminum. The vent plate (70) may be made of the same or different material as the can housing (10).

[0140] The vent plate (70) includes a plate body (71) and a vent notch portion (74).

[0141] The plate body (71) can be installed to close the opening of the can housing (10). The plate body (71) can be formed in an overall circular shape. The plate body (71) can be manufactured to an appropriate thickness considering the capacity or internal pressure of the battery cell.

[0142] The vent notch portion (74) may be formed on the plate body (71) to be thinner than the thickness of the plate body (71). The vent notch portion (74) may be formed along the circumferential direction at a portion spaced apart from the center of the plate body (71) by a certain radius. The vent notch portion (74) may be formed in a continuous circular or oval shape or may be formed in a broken line shape. The vent notch portion (74) may be cut or broken when the internal pressure of the can housing (10) exceeds a preset pressure. As the vent notch portion (74) is cut or broken, the internal gas of the can housing (10) may be discharged to the outside.

[0143] The plate body (71) may include a center portion (72) disposed on the inside of the vent notch portion (74) and a rim portion (73) disposed on the outside of the vent notch portion (74). The center portion (72) may be formed in a circular panel shape, and the rim portion (73) may be formed in an annular panel shape to surround the center portion (72). When the vent notch portion (74) is cut or broken as the internal pressure of the can housing (10) increases, the center portion (72) is separated from the vent plate (70), and the rim portion (73) remains pressed against the crimping portion (17). Accordingly, a break opening is formed on the inside of the rim portion (73) at the portion where the center portion (72) is removed.

[0144] The negative electrode collector plate (50) includes a support portion (51) and a plurality of bridge portions (55). The support portion (51) includes a support ring portion (52) and a plurality of support ribs (53).

[0145] The support ring portion (52) is arranged at the axial end of the electrode assembly (20). A support hole portion (52a) is formed at the center of the support ring portion (52) to correspond to the core portion (29) of the electrode assembly (20). The support hole portion (52a) is formed to have a diameter almost identical to the core portion (29) and can be arranged to be concentric with the core portion (29). The support hole portion (52a) can be formed in a circular shape.

[0146] A plurality of support ribs (53) extend radially outward from the support ring portion (52) and are joined to the axial end of the electrode assembly (20). The plurality of support ribs (53) can be joined to the electrode assembly (20) by welding or adhesive.

[0147] A plurality of bridge portions (55) extend radially outward from the support ring portion (52) and can be electrically connected to the can housing (10). A bridge notch portion is formed in the bridge portion (55) so that shear stress can be concentrated in the bridge portion. The bridge notch portion (58) may be a bridge notch groove formed on both sides of the width direction of the bridge portion (55). The bridge portion (55) may be welded to the beading groove portion (16) of the can housing (10).

[0148] The support rib (53) is primarily welded to the laid electrode tab of the electrode assembly (20), and the bridge portion (55) is secondarily welded to the beading groove portion (16) of the can housing (10). Accordingly, the negative electrode of the electrode assembly (10) can be electrically connected to the can housing (10) via the negative electrode collector plate (50).

[0149] The plurality of support ribs (53) can be fixed by welding to the end of the electrode assembly (20), the support ring portion (52) can be installed without being welded to the end of the electrode assembly (20), and a bridge notch portion (58) can be formed in each of the plurality of bridge portions (55).

[0150] When thermal runaway occurs in the battery cell, the greatest pressure is applied to the support ring portion (52) that has the largest surface area but is not welded to the end of the electrode assembly (20). At this time, since the support rib (53) is welded to the end of the electrode assembly (20), the shear stress is first concentrated at the connection portion between the support rib (53) and the electrode tab, and after the support rib (53) is torn and separated from the end of the electrode assembly (20), the shear stress is concentrated at the bridge notch portion (58). Then, when the bridge notch portion (58) of the bridge portion (55) is broken as the support ring portion (52) rises in the axial direction, the support ring portion (52) is discharged to the outside through the break opening.

[0151] According to the embodiment, as the support ring portion (52) is strongly pressed in the axial direction, shear stress is concentrated on the bridge notch portion (58), so that the support ring portion (52) can be separated from the end of the electrode assembly (20) as the thin bridge notch portion (58) is torn or broken. The separated support ring portion (52) can be discharged to the outside through the broken opening of the vent plate (70) due to the internal pressure.

[0152] In this way, when the battery cell thermally overheats, the shear stress is gradually concentrated on the welding portion of the support rib (53) and the bridge notch portion (58), causing the welding portion and the bridge notch portion (58) to be sequentially broken, so that the support ring portion (52) and the support rib (53) can be removed more quickly from the end of the electrode assembly (20).

[0153] In addition, since the support ring portion (52) blocking the axial end of the electrode assembly (20) is removed, loose parts or fragments of the electrode assembly (20) due to internal pressure can be smoothly discharged through the rupture opening. Accordingly, the residual amount of the electrode assembly (20) that causes combustion or explosion inside the can housing (10) can be further reduced. In addition, since the residual amount of the electrode assembly (20) inside the can housing (10) is quickly reduced, the thermal runaway time can be significantly shortened, and the flame or thermal runaway can be prevented from spreading to the surrounding battery cells.

[0154] The bridge notch portion (54) may be arranged on the inner side of the axial projection surface (74a) of the vent notch portion (74). That is, the support ring portion (52) arranged on the inner side of the bridge notch portion (54) is formed to be smaller than the size of the vent notch portion (74) and is arranged on the lower side of the vent notch portion (74). Accordingly, when the battery cell experiences thermal runaway, the support ring portion (52) can smoothly pass through the fracture opening of the vent plate (70) after being separated from the electrode assembly (20).

[0155] At this time, there is a possibility that the support rib (53) may extend outward from the periphery of the support ring portion (52) and get caught on the rim portion (73) of the vent plate (70), but as the support rib (53) bends, the support ring portion (52) and the support rib (53) can smoothly pass through the fracture opening. Accordingly, the support ring portion (52) can be prevented from getting caught on the rim portion (52) of the vent plate (70) and blocking the fracture opening.

[0156] Since the support ring portion (52) and the bridge notch portion (58) are arranged on the inner side of the axial projection surface (74a) of the vent notch portion (74), the portion (exposed area) not covered by the support ring portion (52) at the end of the electrode assembly (20) is further increased. Accordingly, when thermal runaway of the battery cell occurs, fragments of the electrode assembly (20) can be smoothly discharged through the fracture opening via the exposed area before the support ring portion (52) is torn off from the end of the electrode assembly (20).

[0157] In addition, when the support ring portion (52) and the support rib (53) are torn and separated from the end of the electrode assembly (20) during thermal runaway of the battery cell, the separated support ring portion (52) and the support rib (53) can be discharged to the outside of the can housing (10) through the fracture opening on the inside of the rim portion (73). In this way, after the support ring portion (52) and the support rib (53) are separated from the bridge portion, the axial end of the electrode assembly (20) is entirely exposed to the outside, so that loose parts or separated fragments from the electrode assembly (20) can be smoothly discharged to the outside of the can housing (10) through the fracture opening on the inside of the rim portion (73).

[0158] Furthermore, the residual amount of the electrode assembly (20) that causes combustion or explosion inside the can housing (10) in a battery cell where thermal runaway has occurred can be further reduced. Since the residual amount of the electrode assembly (20) inside the can housing (10) is quickly reduced, the thermal runaway time can be significantly shortened, and the spread of flames or thermal runaway to surrounding battery cells can be prevented.

[0159] The vent notch portion (74) may be formed in a circular shape concentric with the support ring portion (52). In addition, the bridge notch portion (58) may be arranged along the circumferential direction so as to be concentric with the support ring portion (52). At this time, the radius of the bridge notch portion (58) may be formed to be larger than the radius of the support ring portion (52). Since the bridge notch portion (58) is concentric with the support ring portion (52), even if the support ring portion (52) is partially separated and stands up obliquely when thermal runaway occurs, it can smoothly pass through the fracture opening.

[0160] The support ring portion (52) can be arranged to be concentric with the core portion (29) of the electrode assembly (20). At this time, the support hole portion (52a) formed at the center of the support ring portion (52) can be aligned with the core portion (29).

[0161] A plurality of support ribs (53) extend radially outward from the support ring portion (52). The radially outer ends of the plurality of support ribs (53) may be arranged on the outer side of the projection surface (74a) of the vent notch portion (74). The plurality of support ribs (53) may extend radially from the support ring portion (52). Since the support ribs (53) extend to form free ends from the support ring portion (52), the support ribs (53) may be elastically deformed and welded in close contact with the axial end of the electrode assembly (20). Accordingly, the welding strength of the support ribs (53) may be increased.

[0162] A plurality of bridge portions (55) are connected to the support ring portion (52), and the plurality of bridge portions (55) can be radially arranged between support ribs (53). At this time, a pair of support ribs (53) are arranged on both sides in the width direction of the bridge portion (55), and the pair of support ribs (53) can be welded to the electrode assembly (20). Accordingly, the bridge portion (55) can be stably supported by the bonding force of the pair of support ribs (53).

[0163] The bridge portion (55) may include a leg portion (56) extending radially from the periphery of the support ring portion (52) and having a bridge notch portion (58) formed therein, and a leg mounting portion (57) connected to the leg portion (56) and welded to the crimping portion (17) of the can housing (10). Since the support ring portion (52) is formed to be smaller than the axial projection surface (74a) of the vent notch portion (74), the length of the leg portion (56) can be formed to be relatively longer as the support ring portion (52) becomes smaller. In addition, the width of the leg mounting portion (57) may be formed to be longer than the width of the leg portion (56).

[0164] The leg portion (56) can be formed to be inclined radially with respect to the support ring portion (52). At this time, since the leg portion (56) extends from the support ring portion (52) and is seated on the outer side of the beading groove portion (16), the inclination angle of the leg portion (56) can be adjusted according to the heights of the support ring portion (52) and the beading groove portion (16).

[0165] At this time, since the bridge portion (55) is loosely connected to the support ring portion (52), stress is hardly concentrated on the bridge portion (55) before the support ring portion (52) of the current collector plate (50) is separated from the end of the electrode assembly (20). After the support ring portion (52) is separated from the end of the electrode assembly (20), stress is concentrated on the bridge portion (55), which may cause the bridge notch portion (58) to tear or break. If the bridge notch portion (58) is torn or broken, the support portion (51) separated from the bridge portion (55) can be smoothly discharged through the break opening of the vent plate (70).

[0166] The bridge notch portion (58a) can be formed at the boundary between the support ring portion (52) and the bridge portion (55) as illustrated in Fig. 17. The bridge notch portion (58) can be formed in a straight line or a broken line shape parallel to the width direction of the bridge portion (55).

[0167] The bridge notch portion (58a) can be positioned radially outwardly at a certain distance (G) from the boundary between the support ring portion (52) and the bridge portion (55), as shown in FIGS. 19 and 20.

[0168] The bridge notch portion above may be applied in both the form illustrated in Fig. 16 and the form illustrated in Fig. 18. That is, as illustrated in Fig. 16, it is also possible to reduce the width in the width direction intersecting the extension direction, and form a notch groove in the thickness direction at the reduced width location, as illustrated in Fig. 18.

[0169] At least one ring notch portion (59) may be formed in the support ring portion (52) as shown in FIGS. 19 and 20. When the battery cell experiences thermal runaway, the ring notch portion (59) may be torn or broken, thereby causing the support ring portion (59) to be deformed into a curved shape or separated into multiple pieces.

[0170] The ring notch portion (59) may be formed in a straight line along the radial direction of the support ring portion (52). Of course, the ring notch portion (59) may be formed in a groove shape on both sides or one side in the radial direction. Accordingly, the support ring portion (52) may be torn or broken in the radial direction and separated into multiple pieces.

[0171] The ring notch portion above may be applied in both the form illustrated in Fig. 16 and the form illustrated in Fig. 18. That is, as illustrated in Fig. 16, it is also possible to reduce the width in the radial direction intersecting the extension direction (circumferential direction), and form a notch groove in the thickness direction at the reduced width location, as illustrated in Fig. 18.

[0172] The ring notch portion (59) can be formed between the support rib (53) and the bridge portion (55) in the support ring portion (52). Accordingly, the current collector plate (50) can be separated into pieces in which the support rib (53) and the bridge portion (55) are connected.

[0173] The embodiment exemplifies a structure in which both the ring notch portion and the bridge notch portion are formed, as illustrated in FIGS. 19 and 20. However, the present invention does not exclude a structure in which only the ring notch portion is formed without the bridge notch portion.

[0174] The embodiment exemplifies a structure in which one support rib and one bridge portion are connected between two adjacent ring notches, as illustrated in FIGS. 19 and 20. However, the present invention is not limited to this connection structure and arrangement. For example, only two ring notches may be formed, and two support ribs and two bridge portions may be connected between two adjacent ring notches. Alternatively, eight ring notches may be formed, and only one support rib or only one bridge portion may be connected between two adjacent ring notches.

[0175] FIG. 21 is a cross-sectional view schematically illustrating a state in which pressure is applied to a vent plate when thermal runaway occurs in a battery cell according to the present invention, FIG. 22 is a cross-sectional view schematically illustrating a state in which a center portion is separated as a vent notch portion of a vent plate is broken when thermal runaway occurs in a battery cell according to the present invention, and FIG. 23 is a cross-sectional view schematically illustrating a state in which a majority of an electrode assembly is discharged to the outside through a broken opening portion of a vent plate when thermal runaway occurs in a battery cell according to the present invention.

[0176] Referring to FIGS. 21 to 23, when thermal runaway occurs inside a battery cell, the internal pressure of the can housing (10) increases rapidly. At this time, the internal pressure of the can housing (10) is concentrated on the support portion (51) and the vent plate (70).

[0177] When the internal pressure of the can housing (10) increases beyond the preset pressure (design pressure), the vent notch portion (74) of the vent plate (70) is torn or broken. As the vent notch portion (74) is broken, the center portion (72) is separated from the rim portion (73) and discharged to the outside of the can housing (10). When the center portion (72) is removed from the rim portion (73), a broken opening is formed on the inside of the rim portion (73).

[0178] Before the support ring portion (52) is torn off from the end of the electrode assembly (20), fragments generated at the periphery of the electrode assembly (20) are smoothly discharged through the fracture opening of the vent plate (70).

[0179] In addition, when the support ring portion (52) is torn off and separated from the end of the electrode assembly (20), the separated support ring portion (52) is discharged to the outside of the can housing (10) through the fracture opening on the inside of the rim portion (73). At this time, since the support portion (52) is formed smaller than the vent notch portion (74), it can smoothly pass through the fracture opening.

[0180] When the support ring portion (52) is separated from the end of the electrode assembly (20), the axial end of the electrode assembly (20) is entirely exposed to the outside. Accordingly, loose parts or separated fragments from the electrode assembly (20) can be discharged to the outside of the can housing (10) through the break opening on the inside of the rim portion (73).

[0181] As described above, after the support ring portion (52) is removed from the electrode assembly (20), it is smoothly discharged from the can housing (10), and the electrode assembly (20), which causes combustion or explosion, can be quickly discharged from the can housing (10). Accordingly, the thermal runaway time in the battery cell can be shortened, and the thermal runaway or flame can be prevented from spreading to surrounding battery cells.

[0182] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

A can housing having an opening formed on one side; An electrode assembly accommodated inside the can housing; A current collector plate disposed at an axial end of the electrode assembly; and A vent plate is disposed on the axial outer side of the above collector plate and covers the opening of the can housing; The above collector plate, A support ring portion arranged at an axial end of the electrode assembly and having a support hole portion formed to correspond to a core portion of the electrode assembly; A plurality of support ribs extending radially outward from the support ring portion and joined to the axial end of the electrode assembly; and A plurality of bridge portions extending radially outward from the support ring portion and electrically connected to the can housing; A cylindrical battery cell, wherein a plurality of plate notches are formed on the above current collector plate, and at least one of the plurality of plate notches divides the current collector plate into two or more parts. In claim 1, a vent notch portion is formed in the vent plate, A cylindrical battery cell, wherein the plurality of plate notches are arranged on the inner side of the axial projection surface of the vent notch. In claim 2, the vent notch portion is formed to be concentric with the support ring portion, A cylindrical battery cell, wherein at least some of the plurality of plate notches are arranged along the circumference so as to be concentric with the support ring. In claim 1, the plurality of plate notches include a plurality of bridge notches formed in each of the plurality of bridge notches, A cylindrical battery cell, wherein the bridge notch portion is defined by a portion where the width of the bridge is narrowed by bridge notch grooves formed on both sides of the width direction of the bridge portion. In claim 1, the plurality of plate notches include a plurality of bridge notches formed in each of the plurality of bridge notches, A cylindrical battery cell in which the bridge notch portion is formed in a continuous or discrete line shape that crosses the bridge portion in the width direction. In claim 1, the plurality of plate notches include a plurality of bridge notches formed in each of the plurality of bridge notches, A cylindrical battery cell, wherein the bridge notch portion is formed at the boundary between the support ring portion and the bridge portion. In claim 1, the plurality of plate notches include a plurality of bridge notches formed in each of the plurality of bridge notches, A cylindrical battery cell, wherein the bridge notch portion is formed at a portion spaced a certain distance radially outward from the boundary between the support ring portion and the bridge portion. In claim 2, the plurality of bridge portions are radially arranged between the plurality of support ribs, A cylindrical battery cell, wherein the outer end of the above support rib is arranged on the outer side of the above projection surface. A cylindrical battery cell according to claim 1, wherein the plurality of plate notches include at least one ring notch formed in the support ring. A cylindrical battery cell according to claim 9, wherein the ring notch portion is formed between the support rib and the bridge portion in the support ring portion. A cylindrical battery cell according to claim 9, wherein the ring notch portion is formed in the form of a continuous or interrupted line radially crossing the support ring portion. In claim 9, the ring notch portion is a cylindrical battery cell defined by a portion where the width of the ring is narrowed by notch grooves formed on the radially outer and inner sides of the support ring portion, respectively. A cylindrical battery cell according to claim 9, wherein at least one bridge portion and at least one support rib are connected to a section between two ring notch portions adjacent to each other in the circumferential direction of the support ring portion. A cylindrical battery cell according to claim 2, wherein the outer ends of the plurality of support ribs are arranged radially outer than the projection surface. A cylindrical battery cell according to claim 14, wherein the plurality of support ribs are arranged along the circumferential direction of the support ring portion and extend radially.

Images