Battery pack

Abstract

The present disclosure relates to a battery pack, and the technical problem to be solved is to provide a battery pack capable of reducing damage due to thermal runaway of a secondary battery. To this end, the present disclosure provides a battery pack comprising: a housing; at least one secondary battery which is disposed inside the housing and comprises a case having a terminal plate, an electrode assembly disposed inside the case, a terminal protruding to the outside of the terminal plate, and a venting line recessed into the terminal plate; a first connection tab which is disposed opposite to the terminal plate and connected to the terminal; and a first breakage line which extends across the first connection tab.

Description

battery pack

[0001] The present disclosure relates to a battery pack.

[0002] In general, the demand for high-energy-density, high-capacity rechargeable batteries is rapidly increasing in line with the recent rapid proliferation of battery-powered electronic devices such as mobile phones, laptop computers, and electric vehicles. Accordingly, research and development to improve the performance of lithium-ion batteries is actively underway.

[0003] A lithium secondary battery is a battery comprising a positive electrode and a negative electrode containing an active material capable of lithium ion intercalation and deintercalation, and an electrolyte, which produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated or deintercalated from the positive and negative electrodes.

[0004] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art.

[0005] The purpose of the present invention is to provide a battery pack capable of reducing damage caused by thermal runaway of a secondary battery.

[0006] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below.

[0007] To solve the above technical problem, a battery pack according to the present invention comprises: a housing; a case having a terminal plate and an electrode assembly disposed inside the case, a terminal protruding outwardly from the terminal plate and a venting line formed concavely inwardly from the terminal plate, and one or more secondary batteries disposed inside the housing; a first connection tab disposed facing the terminal plate and connected to the terminal; and a first break line extending across the first connection tab.

[0008] The first connection tab extends in a direction intersecting the venting line, and the first breaking line can be arranged parallel to the venting line.

[0009] The above venting line can be extended along the circumferential direction centered on the central axis of the secondary battery.

[0010] The distance from the central axis of the secondary battery to the venting line and the distance from the central axis of the secondary battery to the first fracture line may be different from each other.

[0011] The terminal plate comprises: a first terminal plate supporting the terminal; and a second terminal plate arranged to surround the first terminal plate; wherein the venting line is arranged between the first terminal plate and the second terminal plate, and the first breaking line may be arranged to face at least one of the first terminal plate and the second terminal plate.

[0012] The first breaking line may include a first inner line positioned facing the first terminal plate; and a first outer line spaced apart from the first inner line and positioned facing the second terminal plate.

[0013] The distance from the central axis of the secondary battery to the first outer line may be greater than the distance from the central axis of the secondary battery to the first inner line.

[0014] The distance between the first inner line and the first outer line may be greater than the width of the venting line.

[0015] The absolute value of the difference between the distance from the central axis of the secondary battery to the venting line and the distance from the central axis of the secondary battery to the first inner line may be 0.2 mm or more and 1 mm or less.

[0016] The first inner line may include a plurality of first inner holes that penetrate the first connection tab and are arranged along a direction parallel to the venting line.

[0017] The cross-sectional area of ​​the first inner hole may increase as it faces the first terminal plate.

[0018] The first inner line may include a first inner notch that is formed concavely into the inner side of the first connection tab and extends parallel to the venting line.

[0019] It may further include a second connection tab spaced apart from the first connection tab and connected to the terminal plate; and a second break line extending across the second connection tab.

[0020] The second connection tab is extended in a direction intersecting the venting line, and the second break line is arranged parallel to the venting line, and the distance from the central axis of the secondary battery to the venting line and the distance from the central axis of the secondary battery to the second break line may be different from each other.

[0021] The terminal plate comprises: a first terminal plate supporting the terminal; and a second terminal plate arranged to surround the first terminal plate; wherein the venting line is arranged between the first terminal plate and the second terminal plate, and the second breaking line may be arranged to face at least one of the first terminal plate and the second terminal plate.

[0022] The second rupture line may include: a second inner line positioned facing the first terminal plate; and a second outer line spaced apart from the second inner line and positioned facing the second terminal plate.

[0023] The distance from the central axis of the secondary battery to the second outer line may be greater than the distance from the central axis of the secondary battery to the second inner line.

[0024] The distance between the second inner line and the second outer line may be greater than the width of the venting line.

[0025] The second inner line may include a plurality of second inner holes that penetrate the second connection tab and are arranged along a direction parallel to the venting line.

[0026] The second inner line may include a second inner notch that is formed concavely into the inner side of the second connection tab and extends parallel to the venting line.

[0027] According to the present invention, since the venting line is positioned at the same location as the terminal, damage to the cooling plate, etc. located on the lower side of the secondary battery can be prevented due to flames or gases discharged from the venting line in the event of ignition or thermal runaway of the secondary battery.

[0028] According to the present invention, it is possible to prevent the phenomenon in which flames or gases generated during ignition or thermal runaway of a secondary battery are not smoothly discharged by the connection tab, and to prevent secondary damage resulting therefrom.

[0029] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0030] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0031] FIG. 1 is a perspective view schematically showing the configuration of a battery pack according to one embodiment of the present invention.

[0032] FIG. 2 is a plan view schematically showing the configuration of a battery pack according to one embodiment of the present invention.

[0033] FIG. 3 is a perspective view schematically showing the configuration of a secondary battery according to one embodiment of the present invention.

[0034] FIG. 4 is a cross-sectional view schematically showing the configuration of a secondary battery according to one embodiment of the present invention.

[0035] FIG. 5 is a cross-sectional view schematically showing the configuration of a venting line according to one embodiment of the present invention.

[0036] FIG. 6 is a plan view schematically showing the configuration of a venting line according to one embodiment of the present invention.

[0037] FIG. 7 is a plan view schematically showing the configuration of a first fracture line according to one embodiment of the present invention.

[0038] FIG. 8 is a cross-sectional view schematically showing the configuration of a first inner hole according to one embodiment of the present invention.

[0039] FIG. 9 is a plan view schematically showing the configuration of a second fracture line according to one embodiment of the present invention.

[0040] FIG. 10 is a cross-sectional view schematically showing the configuration of a second inner hole according to one embodiment of the present invention.

[0041] FIGS. 11 and 12 are schematic diagrams illustrating the operating state of a battery pack according to one embodiment of the present invention.

[0042] FIG. 13 is a plan view schematically showing the configuration of a first fracture line and a second fracture line according to another embodiment of the present invention.

[0043] FIG. 14 is a cross-sectional view schematically showing the configuration of a first inner line and a first outer line according to another embodiment of the present invention.

[0044] FIG. 15 is a cross-sectional view schematically showing the configuration of a second inner line and a second outer line according to another embodiment of the present invention.

[0045] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0046] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0047] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0048] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0049] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0050] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0051] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0052] Furthermore, where one component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected or coupled to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "coupled" through another component.

[0053] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions such as “one or more” and “one or more” preceding a list of elements modify the entire list of elements and do not modify individual elements of the list.

[0054] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less, unless specifically stated otherwise.

[0055] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0056] The term "use" may be considered synonymous with the term "utilize." As used herein, "substantially," "about," and similar terms are used as terms of approximation rather than degree, and are intended to account for the inherent variation of measured or calculated values ​​that a person skilled in the art would recognize.

[0057] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0058] Spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used herein for ease of explanation to describe the relationship between one element or feature and another element(s) or feature(s) as illustrated in the drawings. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, an element described as "below" or "below" is understood as "above" or "upper" of another element. Thus, the term "below" may encompass both the up and down directions.

[0059] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0060] FIG. 1 is a perspective view schematically showing the configuration of a battery pack according to one embodiment of the present invention, and FIG. 2 is a plan view schematically showing the configuration of a battery pack according to one embodiment of the present invention.

[0061] Referring to FIGS. 1 and 2, the battery pack according to the present embodiment includes a housing (10), a secondary battery (20), a first connection tab (30), and a first break line (40).

[0062] The housing (10) forms the general outline of the battery pack and can provide a space in which the secondary battery (20) can be accommodated.

[0063] The housing (10) according to the present embodiment may include a housing body (11) and a cover (12).

[0064] The housing body (11) can be formed to have a box shape with an empty interior and one side open. The cross-sectional shape of the housing body (11) is not limited to the square shape shown in FIG. 1, but can be designed to have various shapes such as polygons, circles, and ellipses.

[0065] The first direction described below can be exemplified as the length direction of the housing body (11) being parallel to the Y-axis with respect to FIG. 1, the width direction of the housing body (11) being exemplified as the X-axis being exemplified as the height direction of the housing body (11) being exemplified as the Z-axis being exemplified as the height direction of the housing body (11).

[0066] The cover (12) is attached to the housing body (11) and can close the internal space of the housing body (11). For example, the cover (12) may be formed to have a shape roughly like a plate and positioned to face the open side of the housing body (11). The cover (12) can be fixed to the housing body (11) by various types of joining methods, such as bolting, welding, or snap-fitting.

[0067] The secondary battery (20) can function as a unit structure for charging and discharging power in a battery pack. The secondary battery (20) can be placed inside the housing (10). The central axis (C) of the secondary battery (20) can be placed parallel to the height direction of the housing (10), that is, the Z-axis direction with respect to FIG. 1.

[0068] One or more secondary batteries (20) may be provided. In the following description, the secondary batteries (20) are provided in multiple numbers. However, the battery pack according to the present embodiment may also be configured to include only a single secondary battery (20).

[0069] Multiple secondary batteries (20) can be arranged to form various patterns inside the housing (10). For example, multiple secondary batteries (20) can be arranged in two or more rows along the length and width directions of the housing (10). Multiple secondary batteries (20) can be arranged parallel to each other. The arrangement of multiple secondary batteries (20) is not limited to the arrangement shown in FIG. 2, and the design can be modified in various forms.

[0070] FIG. 3 is a perspective view schematically showing the configuration of a secondary battery according to one embodiment of the present invention, and FIG. 4 is a cross-sectional view schematically showing the configuration of a secondary battery according to one embodiment of the present invention.

[0071] Referring to FIGS. 3 and 4, the secondary battery (20) according to the present embodiment includes an electrode assembly (100), a case (200), a terminal (300), and a venting line (400).

[0072] In the following description, the secondary battery is described as a cylindrical battery as a lithium-ion secondary battery. However, the present invention is not limited thereto, and the secondary battery may be a lithium polymer battery or a prismatic battery.

[0073] The electrode assembly (100) can function as a unit structure that performs charging and discharging operations of power in a secondary battery.

[0074] The electrode assembly (100) may include a first electrode (110), a second electrode (120), and a separator (130) disposed between the first electrode (110) and the second electrode (120).

[0075] The electrode assembly (100) may have a shape wound around a winding axis.

[0076] More specifically, the electrode assembly (100) may have a shape in which the first electrode (110), the separator (130), and the second electrode (120) are stacked and wound along a clockwise or counterclockwise direction around a winding axis. Accordingly, the electrode assembly (100) may have a shape roughly like a jelly roll. The cross-sectional shape of the electrode assembly (100) can be designed to have various shapes, such as an ellipse or a polygon, in addition to a circular shape. The winding axis of the electrode assembly (100) may be positioned on the same straight line as the central axis (C) of the secondary battery (20).

[0077] The first electrode (110) can function as the positive electrode of the electrode assembly (100). The first electrode (110) may be formed to have the form of a foil containing a metal material such as aluminum or an aluminum alloy. The type, size, and shape of the first electrode (110) are not particularly limited as long as it is conductive without causing chemical changes in the secondary battery.

[0078] A first active material layer may be applied to at least a portion of the first electrode (110). The first active material layer may be applied to both sides of the first electrode (110), or alternatively, it may be applied to only one side of the first electrode (110).

[0079] As the first electrode (110) functions as an anode, the first active material layer may include an anode active material.

[0080] The cathode active material may be a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound). More specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, iron, and combinations thereof may be used.

[0081] For example, the positive electrode active material may include at least one of lithium-iron-phosphorus oxide (LiFePO4, LFP), lithium-manganese-iron-phosphorus oxide (LiMnFePO4, LMFP), and lithium-nickel-cobalt-manganese oxide (LiNixCoyMnzO2, NCM). Here, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1을 만족할 수 있다. 양극 활물질은 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM) 중 어느 하나만을 포함할 수 있고, 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM)중 어느 두개 또는 이들을 모두 포함하는 것도 가능하다.

[0082] The first active material layer may further include a positive conductive material.

[0083] The positive electrode conductive material is used to impart conductivity to the first active material layer, and any electronically conductive material that does not cause chemical changes can be used. Examples of positive electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc., metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0084] The first active material layer may further include an anode binder.

[0085] The positive binder serves to adhere the particles constituting the positive active material well to each other and also to adhere the positive active material well to the first electrode (110).

[0086] Examples of positive binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0087] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0088] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0089] When using a water-based binder as the anode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0090] The above dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0091] The first electrode (110) may include a first blank portion (111) in which the first active material layer is not coated. The first blank portion (111) may protrude a predetermined distance from one end of the electrode assembly (100) along the winding axis.

[0092] The second electrode (120) can function as the negative electrode of the electrode assembly (100). The second electrode (120) may be formed to have the shape of a foil containing a metal material such as copper, a copper alloy, nickel, or a nickel alloy. The second electrode (120) may be positioned facing the first electrode (110) at a predetermined distance apart.

[0093] The second electrode (120) is not particularly limited in type, size, shape, etc., as long as it is conductive and does not cause chemical changes in the secondary battery.

[0094] A second active material layer may be applied to at least a portion of the second electrode (120). The second active material layer may be applied to both sides of the second electrode (120), or alternatively, it may be applied to only one side of the second electrode (120).

[0095] As the second electrode (120) functions as a negative electrode, the second active material layer may include a negative active material.

[0096] The negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0097] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0098] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn may be used.

[0099] As materials capable of doping and undoping lithium, Si-based negative electrode active materials or Sn-based negative electrode active materials may be used. Si-based negative electrode active materials may be silicon, silicon-carbon composites, SiOx (0 < x < 2), Si-Q alloys (wherein Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or combinations thereof. Sn-based negative electrode active materials may be Sn, SnO2, Sn-based alloys, or combinations thereof.

[0100] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0101] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0102] The above Si-based or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material.

[0103] The second active material layer may further include a cathode conductive material and a cathode binder.

[0104] The cathode conductive material is used to impart conductivity to the second active material layer, and any electronically conductive material that does not cause chemical changes can be used. Examples of cathode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc., metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0105] The negative electrode binder serves to adhere the particles constituting the negative electrode active material well to each other and also to adhere the negative electrode active material well to the second electrode (120).

[0106] Examples of cathode binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0107] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0108] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0109] When a water-based binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0110] The above dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0111] The second electrode (120) may include a second blank portion (121) on which the second active material layer is not applied. The second blank portion (121) may protrude a predetermined distance from the other end of the electrode assembly (100) located on the opposite side of the first blank portion (111) along the winding axis.

[0112] A separator (130) may be placed between the first electrode (110) and the second electrode (120). The separator (130) may perform the function of preventing a short circuit between the first electrode (110) and the second electrode (120) while allowing the movement of lithium ions between the first electrode (110) and the second electrode (120).

[0113] As such a separator (130), polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer membrane of two or more layers thereof may be used, and a mixed multilayer membrane such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0114] The separator (130) may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0115] The porous substrate may be a polymer membrane formed from any one of the following: polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacetal; polyamide; polyimide; polycarbonate; polyetherketone; polyaryletherketone; polyetherimide; polyamideimide; polybenzimidazole; polyethersulfone; polyphenylene oxide; cyclic olefin copolymer; polyphenylene sulfide; polyethylene naphthalate; glass fiber; Teflon; and polytetrafluoroethylene, or a copolymer or mixture of two or more of these.

[0116] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0117] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include, but is not limited to, inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0118] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0119] A pair of separators (130) may be provided. A pair of separators (130) may be arranged to face each other on both sides of the first electrode (110) or the second electrode (120). A pair of separators (130) may be wound together with the first electrode (110) and the second electrode (120) around a winding axis.

[0120] The case (200) forms the general appearance of the secondary battery (20) and can accommodate the electrode assembly (100). The case (200) may be provided to be electrically conductive. For example, the case (200) may include at least one material among steel, stainless steel, aluminum, and aluminum alloy.

[0121] The case (200) may include a can (210) and a cap plate (240).

[0122] The can (210) may be formed to have a cylindrical shape with a roughly circular cross-section. The diameter of the can (210) may be larger than the diameter of the electrode assembly (100). The length of the can (210) parallel to the winding axis of the electrode assembly (100) may be larger than the length of the electrode assembly (100).

[0123] The electrode assembly (100) can be accommodated inside the can (210). The central axis of the can (210) can be positioned on the same straight line as the central axis (C) of the secondary battery (2). The central axis of the can (210) can be positioned to be coaxial with the winding axis of the electrode assembly (100).

[0124] The can (210) may include a terminal plate (220) and an opening (230).

[0125] The terminal plate (220) and the opening (230) may be disposed at each end of the can (210). The terminal plate (220) and the opening (230) may be disposed spaced apart from each other along the winding axis of the electrode assembly (100).

[0126] The terminal plate (220) according to the present embodiment may be formed to have the shape of a disc placed at one end of the can (210). The terminal plate (220) may be positioned inside the housing body (11) so as to face the cover (12). The outer surface of the terminal plate (220) may be formed integrally with the inner surface of the can (210) to seal one end of the can (210). For example, the can (210) and the terminal plate (220) may be formed by a deep drawing process. Alternatively, the terminal plate (220) may be manufactured separately from the can (210), and its outer surface may be joined to the inner surface of the can (210). A through hole into which a terminal (300), described later, is inserted may be formed in the central part of the terminal plate (220).

[0127] The opening (230) according to the present embodiment may be formed to have the shape of a hole penetrating the other end of the can (210). The opening (230) may be positioned inside the housing body (11) so as to face the bottom surface of the housing body (11). Both sides of the opening (230) may be connected to the internal space of the can (210) and the external space of the can (210), respectively. During the manufacturing process of the secondary battery (20), the electrode assembly (100) may be inserted into the interior of the can (210) through the opening (230) together with the electrolyte.

[0128] The first blank portion (111) of the electrode assembly (100) may be positioned to face the terminal plate (220) inside the can (210). The second blank portion (121) of the electrode assembly (100) may be positioned to face the opening (230) inside the can (210).

[0129] A case gasket (G3) that electrically insulates the electrode assembly (100) and the terminal plate (220) may be disposed between the electrode assembly (100) and the terminal plate (220). The case gasket (G3) can function as a component that electrically insulates the electrode assembly (100) and the terminal plate (220) by blocking direct contact between the case (200) and the first electrode (110).

[0130] The case gasket (G3) according to the present embodiment may be positioned between one side of the electrode assembly (100) having a first non-removable portion (111) protruding and the inner side of the terminal plate (220) positioned to face the internal space of the can (210). The case gasket (G3) may be fixed to the inner side of the terminal plate (220) via an adhesive or the like. The case gasket (G3) may be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0131] The cap plate (240) can be configured to seal the opening (230) of the can (210).

[0132] The cap plate (240) according to the present embodiment may be formed to have a roughly disc shape. The cap plate (240) may be placed in the opening (230) of the can (210). The inner surface of the cap plate (240) may be positioned to face the other side of the electrode assembly (100) in which the second blank portion (121) protrudes from the opening (230). The outer surface of the cap plate (240) may be positioned to face the external space of the can (210). The outer surface of the cap plate (240) may be positioned to face the bottom surface of the housing body (11) from inside the housing body (11). The cap plate (240) may be formed of a metal material to ensure mechanical rigidity, or alternatively, it may be formed of a synthetic resin material that does not have electrical conductivity.

[0133] The case (200) according to the present embodiment may further include a beading portion (250) and a crimping portion (260).

[0134] The beading portion (250) may refer to a portion of the can (210) that protrudes from the inner surface of the can (210) toward the central axis of the can (210) within the entire area of ​​the can (210). The beading portion (250) may be formed by pressing the outer surface of the can (210) from the side adjacent to the opening (230). The beading portion (250) may come into contact with the other end of the electrode assembly (100) on which the second beading portion (121) protrudes. Accordingly, the beading portion (250) can prevent the electrode assembly (100) from moving or detaching from inside the can (210). The edge area of ​​the inner surface of the cap plate (240) may be positioned to face the other side of the electrode assembly (100) on which the second beading portion (121) protrudes, with the beading portion (250) in between.

[0135] The crimping portion (260) may be placed at one end of the can (210) in which the opening (230) is formed. The crimping portion (260) may function as a component for securing the cap plate (240) in the opening (230).

[0136] The crimping portion (260) according to the present embodiment may be folded from one end of the can (210) that surrounds the opening (230). The crimping portion (260) may be positioned to face the outer surface of the cap plate (240) which is positioned to face the outer space of the can (210).

[0137] A cap gasket (G1) that electrically insulates the cap plate (240) and the case (200) may be placed between the cap plate (240) and the crimping portion (260).

[0138] The cap gasket (G1) according to the present embodiment may be positioned to completely wrap around the end of the cap plate (240). The outer surface of the cap gasket (G1) may be pressed and fixed to the inner surface of the beading portion (250) and the crimping portion (260). The cap gasket (G1) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc. Accordingly, the cap gasket (G1) electrically insulates the cap plate (240) and the case (200) and can block moisture, foreign substances, etc. from entering between the cap plate (240) and the case (200).

[0139] The crimping portion (260) is positioned to face the other side of the cap plate (240) with the cap gasket (G1) in between, and can press the cap plate (240) toward the beading portion (250) by contacting the cap gasket (G1). Accordingly, the cap plate (240) can be stably fixed on the side of the opening (230) of the case (200).

[0140] The terminal (300) is coupled to the terminal plate (220) and may protrude to the outside of the terminal plate (220). The terminal (300) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0141] The terminal (300) according to the present embodiment can penetrate the terminal plate (220) along the central axis (C) of the secondary battery (20). The central axis of the terminal (300) can be positioned coaxially with the central axis (C) of the secondary battery (20).

[0142] More specifically, the central portion of the terminal (300) can be inserted into the interior of a through hole formed in the terminal plate (220). The outer surface of the terminal (300) can be positioned at a predetermined distance from the inner surface of the through hole formed in the central portion of the terminal plate (220).

[0143] The upper and lower ends of the terminal (300) can be positioned in the inner and outer spaces of the can (210), respectively. The ends of the terminal (300) positioned in the inner and outer spaces of the can (210) are compressed and deformed by riveting and can be positioned to face the outer and inner surfaces of the terminal plate (220), respectively. Accordingly, the edge region of the terminal (300) can have a cross-sectional shape approximately U-shaped.

[0144] A terminal gasket (G2) that electrically insulates the terminal (300) and the case (200) may be placed between the terminal (300) and the case (200).

[0145] The terminal gasket (G2) according to the present embodiment may be arranged to completely surround the inner circumferential surface of the through hole formed in the terminal plate (220) and the outer and inner surfaces of the terminal plate (220) facing both ends of the terminal (300). Both sides of the terminal gasket (G2) may be in close contact with the surfaces of the terminal plate (220) and the terminal (300). The terminal gasket (G2) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0146] The terminal (300) can be electrically connected to the first electrode (110) of the electrode assembly (100). In this embodiment, as the first electrode (110) of the electrode assembly (100) is exemplified as a positive electrode, the terminal (300) can function as a positive electrode terminal of the secondary battery (20).

[0147] For example, the terminal (300) can be connected to the first electrode (110) of the electrode assembly (100) by the first current collector (310).

[0148] The first current collector (310) may be disposed between the electrode assembly (100) and the terminal (300). The first current collector (310) may function as a component that electrically connects the electrode assembly (100) and the terminal (300).

[0149] The first current collector (310) according to the present embodiment may be positioned between one side of the electrode assembly (100) having a first non-removable portion (111) protruding and the other end of the terminal (300) located in the internal space of the case (200). The first current collector (310) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0150] The first current collector (310) may have a shape approximately like a disc. Both sides of the first current collector (310) may be in contact with the first blank portion (111) and the terminal (300), respectively. The end of the first blank portion (111) may be bent in a direction parallel to the first current collector (310) and connected to the lower surface of the first current collector (310) by laser welding, ultrasonic welding, etc. The upper surface of the first current collector (310) may be in contact with the lower surface of the terminal (300) protruding into the interior of the can (210) and connected to the lower surface of the first current collector (310) by laser welding, ultrasonic welding, etc. Accordingly, the first current collector (310) may provide an electrical connection between the electrode assembly (100) and the terminal (300).

[0151] The can (210) can be electrically connected to the second electrode (120) of the electrode assembly (100). In this embodiment, as the second electrode (120) of the electrode assembly (100) is exemplified as a positive electrode, the terminal plate (220) provided in the can (210) can function as a negative electrode terminal of the secondary battery (20).

[0152] For example, the can (210) can be connected to the second electrode (120) of the electrode assembly (100) by the second current collector (320).

[0153] The second current collector (320) may be disposed between the electrode assembly (100) and the cap plate (240). The second current collector (320) may function as a component that electrically connects the electrode assembly (100) and the case (200). The second current collector (320) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0154] The second current collector (320) according to the present embodiment may include a flat portion (321) facing the other side of the electrode assembly (100) on which the second non-removable portion (121) protrudes, and an extension portion (322) extending from the flat portion (321).

[0155] The upper surface of the flat portion (321) facing the other side of the electrode assembly (100) may be connected to the second unwound portion (121). The end of the second unwound portion (121) may be bent in a direction parallel to the flat portion (321) and connected to one side of the flat portion (321) by welding or the like. The bending direction of the second unwound portion (121) may be a direction toward the winding axis of the electrode assembly (100).

[0156] The extension portion (322) may extend from the edge of the flat portion (321) toward the cap plate (240). The extension portion (322) may come into contact with the inner surface of the beading portion (250). The extension portion (322) may be rounded or bent along the beading portion (250). The extension portion (322) may be connected to the beading portion (250) by welding or the like. Accordingly, the case (200) and the second electrode (120) are electrically connected, and the terminal plate (220) can function as a negative terminal.

[0157] The extension portion (322) may be formed in multiple numbers. The multiple extension portions (322) may be spaced apart from each other along the edge of the planar portion (321).

[0158] The venting line (400) may be formed concavely on the inner side of the terminal plate (220). The venting line (400) may function as a configuration that breaks the terminal plate (220) to open the internal space of the case (200) when the internal pressure of the case (200) exceeds a set pressure due to ignition or thermal runaway of the secondary battery (20). Accordingly, the venting line (400) can prevent the explosion of the case (200) in the event of ignition or thermal runaway of the secondary battery (20). In the secondary battery (20) according to the present embodiment, since the venting line (400) is located at the same position as the terminal (300), damage to the cooling plate, etc. located on the lower side of the secondary battery (20) can be prevented in the event of ignition or thermal runaway of the secondary battery (20).

[0159] FIG. 5 is a cross-sectional view schematically showing the configuration of a venting line according to one embodiment of the present invention, and FIG. 6 is a plan view schematically showing the configuration of a venting line according to one embodiment of the present invention.

[0160] Referring to FIGS. 5 and 6, the venting line (400) according to the present embodiment may have the shape of a groove formed concavely from the upper surface of the terminal plate (220) toward the internal space of the case (200). However, the venting line (400) is not limited thereto, and the venting line (400) may also be formed concavely from the lower surface of the terminal plate (220) toward the external space of the case (200).

[0161] The venting line (400) may extend along the circumferential direction centered on the central axis (C) of the secondary battery (20). For example, the venting line (400) may be formed to have a circular shape centered on the central axis (C) of the secondary battery (20).

[0162] The terminal plate (220) according to the present embodiment may include a first terminal plate (221) and a second terminal plate (222).

[0163] The venting line (400) may be positioned between the first terminal plate (221) and the second terminal plate (222). That is, the first terminal plate (221) and the second terminal plate (222) may be different areas of the terminal plate (220) partitioned by the venting line (400).

[0164] The first terminal plate (221) forms the central exterior of the terminal plate (220) and can support the terminal (300).

[0165] The first terminal plate (221) according to the present embodiment may be exemplified as a central region of the terminal plate (220) extending from the venting line (400) toward the central axis (C) of the secondary battery (20). The first terminal plate (221) may have a disc shape with its outer surface surrounded by the venting line (400). The central axis of the first terminal plate (221) may be located coaxial with the central axis (C) of the secondary battery (20).

[0166] The terminal (300) can penetrate the first terminal plate (221) along the central axis (C) of the secondary battery (20). A terminal gasket (G2) can be placed between the terminal (300) and the first terminal plate (221).

[0167] The second terminal plate (222) can form the edge appearance of the terminal plate (220).

[0168] The second terminal plate (222) according to the present embodiment may have a disc shape extending away from the central axis (C) of the secondary battery (20) from the venting line (400). The second terminal plate (222) may be arranged to surround the first terminal plate (221) with the venting line (400) in between. The central axis of the second terminal plate (222) may be located coaxial with the central axis (C) of the secondary battery (20).

[0169] The first connection tab (30) may be positioned facing the terminal plate (220) inside the housing (10). The first connection tab (30) may be electrically connected to the terminal (300). In this embodiment, as the terminal (300) is exemplified as a positive terminal, the first connection tab (30) may be exemplified as a positive tab of a battery pack. The first connection tab (30) may function as a configuration that electrically connects the terminals (300) of a plurality of secondary batteries (20), or provides an electrical connection between the terminal (300) and the control circuit of the battery pack or an external power device.

[0170] The first connection tab (30) may be provided in multiple numbers. Each first connection tab (30) may be individually connected to a terminal (300) of a different secondary battery (20).

[0171] Some of the first connection tabs (30) among the plurality of first connection tabs (30) may be connected integrally, and some of the first connection tabs (30) may be separated from each other. For example, the plurality of first connection tabs (30) arranged along the width direction of the housing (10) may be directly connected, and the plurality of secondary batteries (20) arranged along the width direction of the housing (10) may be connected in parallel.

[0172] A plurality of first connection tabs (30) arranged along the longitudinal direction of the housing (10) are indirectly connected to each other through a second connection tab (50) described later, and a plurality of secondary batteries (20) arranged along the longitudinal direction of the housing (10) can be connected in series. However, the connection form of the plurality of first connection tabs (30) is not limited to the details shown in FIGS. 1 and 2, and the design can be varied depending on the serial and parallel connection forms of the secondary batteries (20).

[0173] The first connection tab (30) according to the present embodiment may have the form of a plate comprising at least one conductive metal among aluminum, nickel, and copper. The first connection tab (30) may extend in a direction intersecting the venting line (400) on the terminal plate (220). The first connection tab (30) may be formed to have a straight shape, and it is also possible to have a bent structure having one or more bending sections. A portion of the first connection tab (30) may be arranged to face the venting line (400) and the housing (10) along the height direction.

[0174] One end of the first connection tab (30) is in contact with the upper surface of the terminal (300) and can be joined to the upper surface of the terminal (300) by welding or the like. The other end of the first connection tab (30) can be connected to the other end of an adjacent first connection tab (30) along the width direction of the housing (10) or connected to a bus bar, etc.

[0175] The first rupture line (40) may be provided to reduce the thickness of a portion of the first connection tab (30) facing the venting line (400). The first rupture line (40) can induce the rupture of the first connection tab (30) when the venting line (400) is opened. Accordingly, the first rupture line (40) can prevent the spread of damage caused by pressure rise, etc., during thermal runaway of the secondary battery (20) by allowing gas, flames, etc., discharged through the venting line (400) to be discharged smoothly. The first rupture line (40) can induce the rupture of the first connection tab (30) when an overcurrent flows through the first connection tab (30). Accordingly, the first rupture line (40) can also be utilized as a configuration to prevent thermal runaway of the secondary battery (20) caused by overcurrent, etc.

[0176] FIG. 7 is a plan view schematically showing the configuration of a first fracture line according to one embodiment of the present invention.

[0177] Referring to FIGS. 1 to 7, the first breaking line (40) according to the present embodiment may be arranged parallel to the venting line (400). As the first connection tab (30) is arranged to intersect the venting line (400), the first breaking line (40) may be extended across the first connection tab (30). Accordingly, when the venting line (400) is opened, the first connection tab (30) is broken along a direction parallel to the venting line (400), thereby completely opening the discharge path for gases, etc. discharged from the venting line (400).

[0178] The distance from the central axis (C) of the secondary battery (20) to the venting line (400) and the distance from the central axis (C) of the secondary battery (20) to the first breaking line (40) may be different. That is, the venting line (400) and the first breaking line (40) may be arranged offset along the radial direction centered on the central axis (C) of the secondary battery (20). The first breaking line (40) may be arranged facing at least one of the first terminal plate (221) and the second terminal plate (222).

[0179] For example, the first breaking line (40) may include a first inner line (41) positioned facing the first terminal plate (221) and a first outer line (42) positioned facing the second terminal plate (222). In the following description, the first breaking line (40) will be described as an example of including both the first inner line (41) and the first outer line (42), but the first breaking line (40) is not limited thereto, and it is also possible to configure it to include only one of the first inner line (41) and the first outer line (42).

[0180] The first inner line (41) and the first outer line (42) may be arranged at a predetermined interval along the radial direction centered on the central axis (C) of the secondary battery (20). The first inner line (41) and the first outer line (42) may be extended along the circumferential direction centered on the central axis (C) of the secondary battery (20). The first inner line (41) and the first outer line (42) may be arranged parallel to the venting line (400). The curvature of the first inner line (41) and the first outer line (42) may be the same as the curvature of the venting line (400). For example, the first inner line (41) and the first outer line (42) may have an arc shape centered on the central axis (C) of the secondary battery (20).

[0181] The distance (d3) from the central axis (C) of the secondary battery (20) to the first outer line (42) may be greater than the distance (d2) from the central axis (C) of the secondary battery (20) to the first inner line (41). The distance (d1) from the central axis (C) of the secondary battery (20) to the venting line (400) may be smaller than the distance (d3) from the central axis (C) of the secondary battery (20) to the first outer line (42), and greater than the distance (d2) from the central axis (C) of the secondary battery (20) to the first inner line (41). That is, based on the plan view of the secondary battery (20) as shown in FIG. 6, the venting line (400) may be positioned between the first inner line (41) and the first outer line (42). Accordingly, the first inner line (41) and the first outer line (42) can induce a portion of the first connection tab (30) facing the venting line (400) to be completely separated when the venting line (400) is opened.

[0182] The distance (w2) between the first inner line (41) and the first outer line (42) may be greater than the width (w1) of the venting line (400). Accordingly, when the venting line (400) is opened, the first inner line (41) and the first outer line (42) form the width of the area separated from the first connection tap (30) to be greater than the width of the venting line (400), thereby preventing the flame or gas discharged from the venting line (400) from interfering with the first connection tap (30).

[0183] The absolute value of the difference (d1-d2) between the distance (d1) from the central axis (C) of the secondary battery (20) to the venting line (400) and the distance (d2) from the central axis (C) of the secondary battery (20) to the first inner line (41) may be 0.2 mm or more and 1 mm or less. Additionally, the absolute value of the difference (d1-d3) between the distance (d1) from the central axis (C) of the secondary battery (20) to the venting line (400) and the distance (d3) from the central axis (C) of the secondary battery (20) to the first outer line (42) may be 0.2 mm or more and 1 mm or less.

[0184] If the absolute value of d1-d2 or the absolute value of d1-d3 is less than 0.2 mm, flame or gas may not be discharged smoothly when the venting line (400) is opened.

[0185] If the absolute value of d1-d2 or the absolute value of d1-d3 is greater than 1 mm, the first inner line (41) and the first outer line (42) may not break smoothly due to pressure such as gas discharged from the venting line (400).

[0186] The first inner line (41) according to the present embodiment may include a first inner hole (41a).

[0187] FIG. 8 is a cross-sectional view schematically showing the configuration of a first inner hole according to one embodiment of the present invention.

[0188] Referring to FIGS. 1 to 8, the first inner hole (41a) according to the present embodiment may have the shape of a hole that penetrates the first connection tab (30) along a direction parallel to the central axis of the secondary battery (20). The cross-sectional shape of the first inner hole (41a) can be designed to have various shapes, such as a polygon or an ellipse, in addition to the circular shape shown in FIG. 7.

[0189] The first inner hole (41a) may be provided in multiple numbers. The multiple first inner holes (41a) may be arranged along a direction parallel to the venting line (400). That is, the multiple first inner holes (41a) may be arranged along a circumference centered on the central axis (C) of the secondary battery (20) and having a radius of the distance (d2) from the central axis (C) of the secondary battery (20) to the first inner line (41). The number of first inner holes (41a) is not limited to the details shown in FIG. 7, and the design can be varied depending on the width of the first connection tab (30), etc.

[0190] The cross-sectional area of ​​the first inner hole (41a) may increase as it faces the first terminal plate (221). Accordingly, the first inner line (41) can be broken more easily by the pressure of the gas discharged from the venting line (400) and flowing into the first inner hole (41a).

[0191] The first outer line (42) according to the present embodiment may include a first outer hole (42a).

[0192] The first outer hole (42a) according to the present embodiment may have the shape of a hole that penetrates the first connection tab (30) along a direction parallel to the central axis of the secondary battery (20). The cross-sectional shape of the first outer hole (42a) can be designed to have various shapes, such as polygons and ellipses, in addition to the circular shape shown in FIG. 7.

[0193] The first outer hole (42a) may be provided in multiple numbers. The multiple first outer holes (42a) may be arranged along a direction parallel to the venting line (400). That is, the multiple first outer holes (42a) may be arranged along a circumference centered on the central axis (C) of the secondary battery (20) and having a radius of the distance (d3) from the central axis (C) of the secondary battery (20) to the first outer line (42). The number of first outer holes (42a) is not limited to the details shown in FIG. 7, and the design can be varied depending on the width of the first connection tab (30), etc.

[0194] The cross-sectional area of ​​the first outer hole (42a) may increase as it faces the second terminal plate (222). Accordingly, the first outer line (42) can be broken more easily by the pressure of the gas discharged from the venting line (400) and flowing into the first outer hole (42a).

[0195] The battery pack according to the present embodiment may further include a second connection tab (50) and a second break line (60).

[0196] The second connection tab (50) may be positioned facing the terminal plate (220) inside the housing (10). The second connection tab (50) may be electrically connected to the terminal plate (220). In this embodiment, as the terminal plate (220) is exemplified as a negative terminal, the second connection tab (50) may be exemplified as a negative tab of a battery pack. The second connection tab (50) may function as a configuration that electrically connects the terminal plates (220) of a plurality of secondary batteries (20), or provides an electrical connection between the terminal plate (220) and the control circuit of the battery pack or an external power device.

[0197] The second connection tab (50) may be provided in multiple numbers. Each second connection tab (50) may be individually connected to the terminal plate (220) of a different secondary battery (20).

[0198] Some of the second connection tabs (50) among the plurality of second connection tabs (50) may be connected integrally, while other parts of the second connection tabs (50) may be separated from each other. For example, the plurality of second connection tabs (50) arranged along the width direction of the housing (10) may be directly connected, and the plurality of secondary batteries (20) arranged along the width direction of the housing (10) may be connected in parallel.

[0199] A plurality of second connection tabs (50) arranged along the longitudinal direction of the housing (10) are indirectly connected to each other through the first connection tab (30), and a plurality of secondary batteries (20) arranged along the longitudinal direction of the housing (10) can be connected in series. However, the connection form of the plurality of second connection tabs (50) is not limited to the details shown in FIG. 1 and FIG. 2, and the design can be varied depending on the serial and parallel connection forms of the secondary batteries (20).

[0200] The second connection tab (50) according to the present embodiment may have the form of a plate comprising at least one conductive metal among aluminum, nickel, and copper. The second connection tab (50) may extend in a direction intersecting the venting line (400) on the terminal plate (220). The second connection tab (50) may be formed to have a straight shape, and it is also possible to have a bent structure having one or more bending sections. A portion of the second connection tab (50) may be arranged to face the venting line (400) and the housing (10) along the height direction.

[0201] One end of the first connection tab (30) is in contact with the upper surface of the terminal plate (220) and can be joined to the upper surface of the terminal plate (220) by welding or the like. The other end of the second connection tab (50) can be connected to the other end of an adjacent second connection tab (50) along the width direction of the housing (10) or connected to the first connection tab (30).

[0202] The second rupture line (60) may be provided to reduce the thickness of a portion of the second connection tab (50) facing the venting line (400). The second rupture line (60) can induce the rupture of the second connection tab (50) when the venting line (400) is opened. Accordingly, the second rupture line (60) can prevent the spread of damage caused by pressure rise, etc., during thermal runaway of the secondary battery (20) by allowing gas, flames, etc., discharged through the venting line (400) to be discharged smoothly. The second rupture line (60) can induce the rupture of the second connection tab (50) when an overcurrent flows through the second connection tab (50). Accordingly, the second rupture line (60) can also be utilized as a configuration to prevent thermal runaway of the secondary battery (20) caused by overcurrent, etc.

[0203] FIG. 9 is a plan view schematically showing the configuration of a second fracture line according to one embodiment of the present invention.

[0204] Referring to FIGS. 1 through 9, the second breaking line (60) according to the present embodiment may be arranged parallel to the venting line (400). As the second connection tab (50) is arranged to intersect the venting line (400), the second breaking line (60) may be extended to cross the second connection tab (50). Accordingly, when the venting line (400) is opened, the second connection tab (50) is broken along a direction parallel to the venting line (400), thereby completely opening the discharge path for gases, etc. discharged from the venting line (400).

[0205] The distance from the central axis (C) of the secondary battery (20) to the venting line (400) and the distance from the central axis (C) of the secondary battery (20) to the second breaking line (60) may be different. That is, the venting line (400) and the second breaking line (60) may be arranged offset along the radial direction centered on the central axis (C) of the secondary battery (20). The second breaking line (60) may be arranged facing at least one of the first terminal plate (221) and the second terminal plate (222).

[0206] For example, the second break line (60) may include a second inner line (61) positioned facing the first terminal plate (221) and a second outer line (62) positioned facing the second terminal plate (222). In the following description, the second break line (60) will be described as an example of including both the second inner line (61) and the second outer line (62), but the second break line (60) is not limited thereto, and it is also possible to configure it to include only one of the second inner line (61) and the second outer line (62).

[0207] The second inner line (61) and the second outer line (62) may be arranged at a predetermined interval along the radial direction centered on the central axis (C) of the secondary battery (20). The second inner line (61) and the second outer line (62) may be extended along the circumferential direction centered on the central axis (C) of the secondary battery (20). The second inner line (61) and the second outer line (62) may be arranged parallel to the venting line (400). The curvature of the second inner line (61) and the second outer line (62) may be the same as the curvature of the venting line (400). For example, the second inner line (61) and the second outer line (62) may have an arc shape centered on the central axis (C) of the secondary battery (20).

[0208] The distance (d5) from the central axis (C) of the secondary battery (20) to the second outer line (62) may be greater than the distance (d4) from the central axis (C) of the secondary battery (20) to the second inner line (61). The distance (d1) from the central axis (C) of the secondary battery (20) to the venting line (400) may be smaller than the distance (d5) from the central axis (C) of the secondary battery (20) to the second outer line (62), and greater than the distance (d4) from the central axis (C) of the secondary battery (20) to the second inner line (61). That is, based on the plan view of the secondary battery (20) as shown in FIG. 6, the venting line (400) may be positioned between the second inner line (61) and the second outer line (62). Accordingly, the second inner line (61) and the second outer line (62) can induce a portion of the second connection tab (50) facing the venting line (400) to be completely separated when the venting line (400) is opened.

[0209] The distance (w3) between the second inner line (61) and the second outer line (62) may be greater than the width (w1) of the venting line (400). Accordingly, when the venting line (400) is opened, the second inner line (61) and the second outer line (62) form the width of the area separated from the first connection tap (30) to be greater than the width of the venting line (400), thereby preventing the flame or gas discharged from the venting line (400) from interfering with the second connection tap (50).

[0210] The absolute value of the difference (d1-d4) between the distance (d1) from the central axis (C) of the secondary battery (20) to the venting line (400) and the distance (d4) from the central axis (C) of the secondary battery (20) to the second inner line (61) may be 0.2 mm or more and 1 mm or less. Additionally, the absolute value of the difference (d1-d5) between the distance (d1) from the central axis (C) of the secondary battery (20) to the venting line (400) and the distance (d5) from the central axis (C) of the secondary battery (20) to the second outer line (62) may be 0.2 mm or more and 1 mm or less.

[0211] If the absolute value of d1-d4 or the absolute value of d1-d5 is less than 0.2 mm, flame or gas may not be discharged smoothly when the venting line (400) is opened.

[0212] If the absolute value of d1-d4 or the absolute value of d1-d5 is greater than 1 mm, the second inner line (61) and the second outer line (62) may not break smoothly due to pressure such as gas discharged from the venting line (400).

[0213] The second inner line (61) according to the present embodiment may include a second inner hole (61a).

[0214] FIG. 10 is a cross-sectional view schematically showing the configuration of a second inner hole according to one embodiment of the present invention.

[0215] Referring to FIGS. 1 to 10, the second inner hole (61a) according to the present embodiment may have the shape of a hole that penetrates the second connection tab (50) along a direction parallel to the central axis of the secondary battery (20). The cross-sectional shape of the second inner hole (61a) can be designed to have various shapes, such as polygons and ellipses, in addition to the circular shape shown in FIG. 9.

[0216] The second inner hole (61a) may be provided in multiple numbers. The multiple second inner holes (61a) may be arranged along a direction parallel to the venting line (400). That is, the multiple second inner holes (61a) may be arranged along a circumference centered on the central axis (C) of the secondary battery (20) and having a radius of the distance (d4) from the central axis (C) of the secondary battery (20) to the second inner line (61). The number of the second inner holes (61a) is not limited to the details shown in FIG. 9, and the design can be varied depending on the width of the second connection tab (50), etc.

[0217] The cross-sectional area of ​​the second inner hole (61a) may increase as it faces the first terminal plate (221). Accordingly, the second inner line (61) can be broken more easily by the pressure of the gas discharged from the venting line (400) and flowing into the second inner hole (61a).

[0218] The second outer line (62) according to the present embodiment may include a second outer hole (62a).

[0219] The second outer hole (62a) according to the present embodiment may have the shape of a hole that penetrates the second connection tab (50) along a direction parallel to the central axis of the secondary battery (20). The cross-sectional shape of the second outer hole (62a) can be designed to have various shapes, such as polygons and ellipses, in addition to the circular shape shown in FIG. 9.

[0220] The second outer hole (62a) may be provided in multiple numbers. The multiple second outer holes (62a) may be arranged along a direction parallel to the venting line (400). That is, the multiple second outer holes (62a) may be arranged along a circumference centered on the central axis (C) of the secondary battery (20) and having a radius of the distance (d5) from the central axis (C) of the secondary battery (20) to the second outer line (62). The number of the second outer holes (62a) is not limited to the details shown in FIG. 9, and the design can be varied depending on the width of the second connection tab (50), etc.

[0221] The cross-sectional area of ​​the second outer hole (62a) may increase as it faces the second terminal plate (222). Accordingly, the second outer line (62) can be broken more easily by the pressure of the gas discharged from the venting line (400) and flowing into the second outer hole (62a).

[0222] The operation of a battery pack according to one embodiment of the present invention will be described below.

[0223] FIGS. 11 and 12 are schematic diagrams illustrating the operating state of a battery pack according to one embodiment of the present invention.

[0224] Referring to FIGS. 1 to 12, when the internal pressure of the case (200) rises above a set size due to thermal runaway of any one of the secondary batteries (20), the venting line (400) is opened.

[0225] Pressure is applied to a portion (31) of the first connection tap (30) located between the first inner line (41) and the first outer line (42) by gas discharged from the venting line (400).

[0226] As the pressure applied to the first connection tab (30) rises above a set size, a portion of the first connection tab (30) (31) is broken along the first inner line (41) and the first outer line (42) and separated from the first connection tab (30).

[0227] In addition, pressure is applied to a portion (51) of the second connection tap (50) located between the second inner line (61) and the second outer line (62) by gas discharged from the venting line (400).

[0228] As the pressure applied to the second connection tap (50) rises above a set size, a portion of the second connection tap (50) (51) is broken along the second inner line (61) and the second outer line (62) and separated from the second connection tap (50).

[0229] Accordingly, gas and flames discharged from the venting line (400) can be discharged smoothly through the broken area of ​​the second connection tap (50) without interfering with the second connection tap (50).

[0230] Hereinafter, a battery pack according to another embodiment of the present invention will be described.

[0231] The battery pack according to the present embodiment may be configured to differ only in the detailed configuration of the first rupture line (40) and the second rupture line (60) from the battery pack according to one embodiment of the present invention.

[0232] Accordingly, in describing the battery pack according to the present embodiment, only the detailed configuration of the first fracture line (40) and the second fracture line (60), which are different from the battery pack according to one embodiment of the present invention, will be described.

[0233] For the remaining components of the battery pack according to this embodiment, the description of the battery pack according to one embodiment of the present invention may be applied as is.

[0234] FIG. 13 is a plan view schematically showing the configuration of a first fracture line and a second fracture line according to another embodiment of the present invention.

[0235] Referring to FIG. 13, the first inner line (41) according to the present embodiment may include a first inner notch (41b).

[0236] FIG. 14 is a cross-sectional view schematically showing the configuration of a first inner line and a first outer line according to another embodiment of the present invention.

[0237] Referring to FIG. 14, the first inner notch (41b) according to the present embodiment may have the shape of a groove formed concavely upward from the lower surface of the first connection tab (30) facing the first terminal plate (221). The first inner notch (41b) may extend along a circumference having a radius of the distance (d2) from the central axis (C) of the secondary battery (20) to the first inner line (41). The cross-sectional area of ​​the first inner notch (41b) may increase as it faces the first terminal plate (221).

[0238] The first outer line (42) according to the present embodiment may include a first outer notch (42b).

[0239] The first outer notch (42b) according to the present embodiment may have the shape of a groove formed concavely upward from the lower surface of the first connection tab (30) facing the second terminal plate (222). The first outer notch (42b) may extend along a circumference having a radius of the distance (d3) from the central axis (C) of the secondary battery (20) to the first outer line (42). The cross-sectional area of ​​the first outer notch (42b) may increase as it faces the second terminal plate (222).

[0240] The second inner line (61) according to the present embodiment may include a second inner notch (61b).

[0241] FIG. 15 is a cross-sectional view schematically showing the configuration of a second inner line and a second outer line according to another embodiment of the present invention.

[0242] Referring to FIG. 15, the second inner notch (61b) according to the present embodiment may have the shape of a groove formed concavely upward from the lower surface of the second connection tab (50) facing the first terminal plate (221). The second inner notch (61b) may extend along a circumference having a radius of the distance (d4) from the central axis (C) of the secondary battery (20) to the second inner line (61). The cross-sectional area of ​​the second inner notch (61b) may increase as it faces the first terminal plate (221).

[0243] The second outer line (62) according to the present embodiment may include a second outer notch (62b).

[0244] The second outer notch (62b) according to the present embodiment may have the shape of a groove formed concavely upward from the lower surface of the second connection tab (50) facing the second terminal plate (222). The second outer notch (62b) may extend along a circumference having a radius of the distance (d5) from the central axis (C) of the secondary battery (20) to the second outer line (62). The cross-sectional area of ​​the second outer notch (62b) may increase as it faces the second terminal plate (222).

[0245] Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0246] Therefore, the technical scope of protection of the present invention should be determined by the following patent claims.

Claims

1. Housing; A case having a terminal plate, an electrode assembly disposed inside the case, a terminal protruding outwardly from the terminal plate, and a venting line formed concavely inwardly from the terminal plate, and one or more secondary batteries disposed inside the housing; A first connection tab positioned facing the terminal plate and connected to the terminal; and A battery pack characterized by including a first break line extending across the first connection tab.

2. In Paragraph 1, The first connection tab above extends in a direction intersecting the venting line, and A battery pack characterized in that the first breaking line is positioned parallel to the venting line.

3. In Paragraph 2, A battery pack characterized in that the above-mentioned venting line extends along the circumferential direction centered on the central axis of the secondary battery.

4. In Paragraph 2, A battery pack characterized in that the distance from the central axis of the secondary battery to the venting line and the distance from the central axis of the secondary battery to the first fracture line are different.

5. In Paragraph 4, The above terminal plate is, A first terminal plate supporting the above terminal; and A second terminal plate arranged to surround the first terminal plate; is included, The above venting line is positioned between the first terminal plate and the second terminal plate, and A battery pack characterized in that the first breaking line is positioned to face at least one of the first terminal plate and the second terminal plate.

6. In Paragraph 5, The above first fracture line is, A first inner line positioned facing the first terminal plate; and A battery pack characterized by including a first outer line spaced apart from the first inner line and positioned facing the second terminal plate.

7. In Paragraph 6, A battery pack characterized in that the distance from the central axis of the secondary battery to the first outer line is greater than the distance from the central axis of the secondary battery to the first inner line.

8. In Paragraph 6, A battery pack characterized in that the distance between the first inner line and the first outer line is greater than the width of the venting line.

9. In Paragraph 6, A battery pack characterized in that the absolute value of the difference between the distance from the central axis of the secondary battery to the venting line and the distance from the central axis of the secondary battery to the first inner line is 0.2 mm or more and 1 mm or less.

10. In Paragraph 6, A battery pack characterized by including a plurality of first inner holes arranged along a direction parallel to the venting line, wherein the first inner line penetrates the first connection tab.

11. In Paragraph 10, A battery pack characterized in that the cross-sectional area of ​​the first inner hole increases as it faces the first terminal plate.

12. In Paragraph 6, A battery pack characterized by including: a first inner line formed concavely into the inner side of the first connection tab and a first inner notch extending parallel to the venting line.

13. In Paragraph 1, A second connection tab spaced apart from the first connection tab and connected to the terminal plate; and A battery pack further comprising a second break line extending across the second connection tab.

14. In Paragraph 13, The second connection tap above extends in a direction intersecting the venting line, and The above second breaking line is positioned parallel to the above venting line, and A battery pack characterized in that the distance from the central axis of the secondary battery to the venting line and the distance from the central axis of the secondary battery to the second fracture line are different.

15. In Paragraph 14, The above terminal plate is, A first terminal plate supporting the above terminal; and A second terminal plate arranged to surround the first terminal plate; is included, The above venting line is positioned between the first terminal plate and the second terminal plate, and A battery pack characterized in that the second rupture line is positioned to face at least one of the first terminal plate and the second terminal plate.

16. In Paragraph 15, The above second fracture line is, A second inner line positioned facing the first terminal plate; and A battery pack characterized by including a second outer line spaced apart from the second inner line and positioned facing the second terminal plate.

17. In Paragraph 16, A battery pack characterized in that the distance from the central axis of the secondary battery to the second outer line is greater than the distance from the central axis of the secondary battery to the second inner line.

18. In Paragraph 16, A battery pack characterized in that the distance between the second inner line and the second outer line is greater than the width of the venting line.

19. In Paragraph 16, A battery pack characterized by including a plurality of second inner holes arranged along a direction parallel to the venting line, wherein the second inner line penetrates the second connection tab.

20. In Paragraph 16, A battery pack characterized by including: a second inner line formed concavely into the inner side of the second connection tab and a second inner notch extending parallel to the venting line.

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