Secondary battery and battery pack comprising same

Abstract

The present disclosure relates to a secondary battery and a battery pack comprising same. The technical problem is to be solved by providing a secondary battery and a battery pack comprising same, the secondary battery being capable of ensuring current-blocking performance under high current and reducing cell resistance. To this end, the present disclosure provides the secondary battery comprising: an electrode assembly; a case, which accommodates the electrode assembly and has an opening part and a closing part; a cap plate for sealing the opening part; a terminal, which passes through the closing part and is arranged to face the electrode assembly; and a first current collection member arranged between the electrode assembly and the terminal, wherein the first current collection member includes: a first plate, which is arranged to face the terminal and is connected to the terminal; a second plate, which is spaced apart from the first plate and is connected to the electrode assembly; a fuse hole arranged between the first plate and the second plate; and first and second bridges, which are arranged inside the fuse hole and are connected to the first and second plates.

Description

Secondary battery and battery pack including the same

[0001] The present disclosure relates to a secondary battery and a battery pack including the same.

[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 secondary battery capable of securing current blocking performance under high current and reducing cell resistance, and a battery pack including the same.

[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] A secondary battery according to the present invention for solving the above technical problem comprises: an electrode assembly; a case that accommodates the electrode assembly and has an opening and a closing portion; a cap plate that seals the opening portion; a terminal that penetrates the closing portion and is positioned facing the electrode assembly; and a first current collector disposed between the electrode assembly and the terminal; wherein the first current collector comprises: a first plate disposed facing the terminal and connected to the terminal; a second plate spaced apart from the first plate and connected to the electrode assembly; a fuse hole disposed between the first plate and the second plate; and a first bridge and a second bridge disposed inside the fuse hole and connected to the first plate and the second plate.

[0008] The sum of the width of the first bridge and the width of the second bridge may be less than or equal to the diameter of the first plate.

[0009] The width of the first bridge and the width of the second bridge may be 1 mm or more and 4 mm or less.

[0010] The width of the second bridge may be greater than the width of the first bridge.

[0011] The difference between the width of the second bridge and the width of the first bridge may be 0.1 mm or more and 1 mm or less.

[0012] The lengths of the first bridge and the second bridge may be 0.5 mm or more and 4 mm or less.

[0013] The length of the second bridge may be smaller than the length of the first bridge.

[0014] The difference between the length of the first bridge and the length of the second bridge may be 0.1 mm or more and 1 mm or less.

[0015] The thickness of the first bridge and the second bridge may be 0.1 mm or more and 1 mm or less.

[0016] The thickness of the second bridge may be greater than the thickness of the first bridge.

[0017] The ratio of the sum of the areas of the first bridge and the second bridge to the area of ​​the fuse hole may be 0.05 or more and 0.3 or less.

[0018] The first current collector may further include a notch formed concavely on the inner side of the first bridge.

[0019] The first current collector may further include an insulating member arranged to surround the first bridge.

[0020] The first current collector may further include a third bridge spaced apart from the first bridge and the second bridge.

[0021] The distance between the first bridge and the second bridge may be smaller than the distance between the first bridge and the third bridge.

[0022] A battery pack according to the present invention comprises: a housing; and a plurality of secondary batteries disposed inside the housing; wherein the secondary batteries comprise: an electrode assembly; a case that accommodates the electrode assembly and has an opening and a closing portion; a cap plate that seals the opening portion; a terminal that penetrates the closing portion and is disposed facing the electrode assembly; and a first current collector disposed between the electrode assembly and the terminal; wherein the first current collector comprises: a first plate disposed facing the terminal and connected to the terminal; a second plate spaced apart from the first plate and connected to the electrode assembly; a fuse hole disposed between the first plate and the second plate; and a first bridge and a second bridge disposed inside the fuse hole and connected to the first plate and the second plate.

[0023] According to the present invention, since multiple bridges are formed to perform a current blocking function when an overcurrent occurs, the heat generation temperature can be relatively lowered compared to the case where a single bridge is formed.

[0024] According to the present invention, stable current blocking performance can be secured by relatively reducing the area of ​​the bridge inversely proportional to the increase in the number of bridges.

[0025] According to the present invention, the timing of current interruption can be precisely controlled as a plurality of bridges are configured to be sequentially melted.

[0026] 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.

[0027] 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.

[0028] FIG. 1 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention.

[0029] FIG. 2 is a cross-sectional view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention.

[0030] FIG. 3 is a perspective view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention.

[0031] FIG. 4 is a plan view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention.

[0032] FIG. 5 is an enlarged view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention.

[0033] FIG. 6 is a cross-sectional view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention.

[0034] FIG. 7 is a plan view schematically showing the configuration of the first bridge and the second bridge according to the second embodiment of the present invention.

[0035] FIGS. 8 and 9 are diagrams schematically illustrating the operation process of a secondary battery according to a second embodiment of the present invention.

[0036] FIG. 10 is a plan view schematically showing the configuration of the first bridge and the second bridge according to the third embodiment of the present invention.

[0037] FIG. 11 is an enlarged view schematically showing the configuration of the first bridge and the second bridge according to the third embodiment of the present invention.

[0038] FIGS. 12 and 13 are diagrams schematically illustrating the operation process of a secondary battery according to a third embodiment of the present invention.

[0039] FIG. 14 is a cross-sectional view schematically showing the configuration of the first bridge and the second bridge according to the fourth embodiment of the present invention.

[0040] FIGS. 15 and 16 are diagrams schematically illustrating the operation process of a secondary battery according to the fourth embodiment of the present invention.

[0041] FIG. 17 is a plan view schematically showing the configuration of a first current collector member according to the fifth embodiment of the present invention.

[0042] FIG. 18 is an enlarged view schematically showing the configuration of a notch according to the fifth embodiment of the present invention.

[0043] FIGS. 19 and 20 are diagrams schematically illustrating the operation process of a secondary battery according to the fifth embodiment of the present invention.

[0044] FIG. 21 is a plan view schematically showing the configuration of a first current collector member according to the sixth embodiment of the present invention.

[0045] FIG. 22 is a cross-sectional view schematically showing the configuration of an insulating member according to the 6th embodiment of the present invention.

[0046] FIGS. 23 and 24 are diagrams schematically illustrating the operation process of a secondary battery according to the 6th embodiment of the present invention.

[0047] FIG. 25 is a plan view schematically showing the configuration of a first current collector member according to the seventh embodiment of the present invention.

[0048] FIG. 26 is an enlarged view schematically showing the configuration of a third bridge according to the seventh embodiment of the present invention.

[0049] FIGS. 27 and 28 are diagrams schematically illustrating the operation process of a secondary battery according to the seventh embodiment of the present invention.

[0050] FIG. 29 is a perspective view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0051] FIG. 30 is a plan view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0058] 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.

[0059] 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.

[0060] 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.

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

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0067] FIG. 1 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention.

[0068] Referring to FIGS. 1 and 2, the secondary battery (2) according to the present embodiment includes an electrode assembly (100), a case (200), a cap plate (300), a terminal (400), and a first current collector (500).

[0069] 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.

[0070] The electrode assembly (100) can function as a unit structure that performs charging and discharging operations of power in a secondary battery.

[0071] The electrode assembly (100) may include a first electrode plate (110), a second electrode plate (120), and a separator (130) disposed between the first electrode plate (110) and the second electrode plate (120).

[0072] The electrode assembly (100) may have a shape wound around a winding axis (C).

[0073] More specifically, the electrode assembly (100) may have a shape in which the first electrode plate (110), the separator (130), and the second electrode plate (120) are stacked and wound along a clockwise or counterclockwise direction around a winding axis (C). Accordingly, the electrode assembly (100) may have a shape roughly resembling 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. Here, the winding axis (C) may refer to a straight line penetrating the center of the electrode assembly (100).

[0074] The first electrode plate (110) can function as the positive electrode of the electrode assembly (100). The first electrode plate (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 plate (110) are not particularly limited as long as it is conductive without causing chemical changes in the secondary battery.

[0075] A first active material layer may be applied to at least a portion of the first electrode plate (110). The first active material layer may be applied to both sides of the first electrode plate (110), or alternatively, it may be applied to only one side of the first electrode plate (110).

[0076] As the first electrode plate (110) functions as an anode, the first active material layer may include an anode active material.

[0077] 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.

[0078] 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.

[0079] The first active material layer may further include a positive conductive material.

[0080] 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.

[0081] The first active material layer may further include an anode binder.

[0082] 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 plate (110).

[0083] Examples of anode binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] The first electrode plate (110) may include a first blank portion (111) in which the first active material layer is not applied. The first blank portion (111) may protrude a predetermined distance from one end of the electrode assembly (100) along the winding axis (C).

[0089] The second electrode plate (120) can function as the negative electrode of the electrode assembly (100). The second electrode plate (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 plate (120) may be positioned facing the first electrode plate (110) at a predetermined distance apart.

[0090] The second electrode plate (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.

[0091] A second active material layer may be applied to at least a portion of the second electrode plate (120). The second active material layer may be applied to both sides of the second electrode plate (120), or alternatively, it may be applied to only one side of the second electrode plate (120).

[0092] As the second electrode plate (120) functions as a negative electrode, the second active material layer may include a negative active material.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] The above Si-based or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material.

[0100] The second active material layer may further include a cathode conductive material and a cathode binder.

[0101] 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.

[0102] 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 plate (120).

[0103] Examples of cathode binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] The second electrode plate (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 (C).

[0109] A separator (130) may be placed between the first electrode plate (110) and the second electrode plate (120). The separator (130) may perform the function of preventing a short circuit between the first electrode plate (110) and the second electrode plate (120) while allowing the movement of lithium ions between the first electrode plate (110) and the second electrode plate (120).

[0110] 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.

[0111] 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.

[0112] 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.

[0113] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0114] 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.

[0115] 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.

[0116] 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 plate (110) or the second electrode plate (120). A pair of separators (130) may be wound together with the first electrode plate (110) and the second electrode plate (120) around a winding axis (C).

[0117] The case (200) forms the general appearance of the secondary battery (2) 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.

[0118] The case (200) may include a can (201), an opening (202), and a closing (203).

[0119] The can (201) may be formed to have a cylindrical shape with a roughly circular cross-section. The diameter of the can (201) may be larger than the diameter of the electrode assembly (100). The length of the can (201) parallel to the winding axis (C) of the electrode assembly (100) may be larger than the length of the electrode assembly (100).

[0120] The electrode assembly (100) can be accommodated inside a can (201). The central axis of the can (201) can be positioned so as to be coaxial with the winding axis (C) of the electrode assembly (100).

[0121] The opening (202) and the closing (203) may be disposed at each end of the can (201). The opening (202) and the closing (203) may be disposed spaced apart from each other along a first direction. The first direction described below may refer to a direction from the opening (202) toward the closing (203) with reference to FIG. 2, among directions parallel to the central axis of the can (201) and the winding axis (C) of the electrode assembly (100).

[0122] The opening (202) according to the present embodiment may be formed to have the shape of a hole penetrating one end of the can (201). Both sides of the opening (202) may be connected to the internal space of the can (201) and the external space of the can (201), respectively. During the manufacturing process of the secondary battery (2), the electrode assembly (100) may be inserted into the interior of the can (201) through the opening (202) together with the electrolyte.

[0123] The closing portion (203) according to the present embodiment may be formed to have the shape of a disc placed at the other end of the can (201) spaced apart along the first direction from the opening portion (202). The outer surface of the closing portion (203) may be formed integrally with the inner surface of the can (201) to seal the other end of the can (201). For example, the can (201) and the closing portion (203) may be formed by a deep drawing process. Alternatively, the closing portion (203) may be manufactured separately from the can (201), and its outer surface may be joined to the inner surface of the can (201). A through hole may be formed in the central portion of the closing portion (203) to provide a path for inserting a terminal (400) described later.

[0124] The first blank portion (111) of the electrode assembly (100) may be positioned to face the closed portion (203) inside the can (201). The second blank portion (121) of the electrode assembly (100) may be positioned to face the open portion (202) inside the can (201).

[0125] A case gasket (G3) that electrically insulates the electrode assembly (100) and the closure (203) may be disposed between the electrode assembly (100) and the closure (203). The case gasket (G3) can function as a component that electrically insulates the electrode assembly (100) and the closure (203) by blocking direct contact between the case (200) and the first electrode plate (110).

[0126] 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 surface of the closure portion (203) positioned to face the internal space of the can (201). The case gasket (G3) may be fixed to the inner surface of the closure portion (203) via an adhesive or the like. The case gasket (G3) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0127] The case (200) according to the present embodiment may further include a beading portion (204).

[0128] The beading portion (204) may refer to a portion of the can (201) that protrudes from the inner surface of the can (201) toward the central axis of the can (201) within the entire area of ​​the can (201). The beading portion (204) may be formed by pressing the outer surface of the can (201) from the side adjacent to the opening (202). The beading portion (204) may come into contact with the other end of the electrode assembly (100) from which the second non-removable portion (121) protrudes. Accordingly, the beading portion (204) can prevent the electrode assembly (100) from moving or detaching inside the can (201).

[0129] The cap plate (300) can be configured to seal the opening (202) of the case (200).

[0130] The cap plate (300) according to the present embodiment may be formed to have a roughly circular shape. The cap plate (300) may be placed inside the can (201). The cap plate (300) may be placed inside the can (201) facing the other end of the electrode assembly (100) with the beading portion (204) in between. One side of the cap plate (300) may be placed on the beading portion (204). The other side of the cap plate (300) may be placed facing the external space of the can (201).

[0131] A crimping portion (205) for fixing a cap plate (300) may be formed at one end of the can (201) in which the opening (202) is formed. The crimping portion (205) according to the present embodiment may be bent from one end of the can (201) and positioned to face the other side of the cap plate (300) which is positioned to face the external space of the can (201).

[0132] A cap gasket (G1) that electrically insulates the cap plate (300) and the case (200) may be placed between the cap plate (300) and the crimping portion (205).

[0133] The cap gasket (G1) according to the present embodiment may be positioned to completely wrap around the end of the cap plate (300). The outer surface of the cap gasket (G1) may be pressed and fixed to the inner surface of the beading portion (204) and the crimping portion (205). 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 (300) and the case (200) and can block moisture, foreign substances, etc. from entering between the cap plate (300) and the case (200).

[0134] The crimping portion (205) is positioned to face the other side of the cap plate (300) with the cap gasket (G1) in between, and can press the cap plate (300) toward the beading portion (204) by contacting the cap gasket (G1). Accordingly, the cap plate (300) can be stably fixed on the side of the opening (202) of the case (200).

[0135] The cap plate (300) can be formed of a metal material to ensure mechanical strength, or alternatively, it can be formed of a synthetic resin material that does not have electrical conductivity.

[0136] The cap plate (300) may be provided with a vent (301) that opens as the internal pressure of the can (201) exceeds the set pressure.

[0137] The vent (301) according to the present embodiment may have a thinner thickness compared to other areas of the cap plate (300). For example, the vent (301) may have the shape of a notch formed concavely from one side of the cap plate (300) toward the other side. The vent (301) may be formed to have a ring shape that is spaced apart from the center of the cap plate (300) and forms a concentric circle with the cap plate (300). As another example, the vent (301) may have at least one pattern having a straight or curved shape.

[0138] The terminal (400) is coupled to the case (200) and can be electrically connected to the electrode assembly (100) by the first current collector (500) described later. The terminal (400) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0139] In this embodiment, the terminal (400) can function as a positive terminal of a secondary battery (2) by being electrically connected to the first electrode plate (110) of the electrode assembly (100) by the first current collector (500). However, the terminal (400) is not limited thereto and can also function as a negative terminal by being electrically connected to the second electrode plate (120).

[0140] The terminal (400) according to the present embodiment may penetrate the closed portion (203) of the case (200) along the first direction. More specifically, the terminal (400) may be inserted into the interior of a through hole formed in the center of the closed portion (203). The outer surface of the terminal (400) may be spaced apart from the inner surface of the through hole formed in the center of the closed portion (203) by a predetermined distance. Both ends of the terminal (400) may be placed in the internal space and the external space of the can (201), respectively.

[0141] Both ends of the terminal (400) positioned in the inner and outer spaces of the can (201) are compressed by riveting and can be positioned to face the outer and inner surfaces of the closure (203), respectively. Accordingly, the edge region of the terminal (400) may have a cross-sectional shape approximately U-shaped. Accordingly, the terminal (400) can be stably fixed to the case (200) while penetrating the closure (203).

[0142] A first terminal surface (401) facing the electrode assembly (100) along a first direction may be formed on one side of the terminal (400) located in the internal space of the can (201). The first terminal surface (401) according to the present embodiment may have a planar shape arranged perpendicular to the first direction.

[0143] On the other side of the terminal (400) located in the external space of the can (201), a second terminal surface (402) spaced apart from the first terminal surface (401) along a first direction may be formed. The second terminal surface (402) according to the present embodiment may have a planar shape facing the external space of the can (201) and arranged parallel to the first terminal surface (401). The terminal (400) may have a structure in which the cross-sectional areas on both sides are different with respect to the closing portion (203).

[0144] A terminal gasket (G2) that electrically insulates the terminal (400) and the case (200) may be placed between the terminal (400) 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 closure portion (203), and the outer surface of the closure portion (203) facing both ends of the terminal (400). Both sides of the terminal gasket (G2) may be in close contact with the surfaces of the closure portion (203) and the terminal (400). The terminal gasket (G2) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0146] The first current collector (500) is disposed between the electrode assembly (100) and the first terminal surface (401) and can be connected to the electrode assembly (100). The first current collector (500) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0147] The first current collector (500) may be positioned between one side of the electrode assembly (100) having a first non-removable portion (111) protruding and the first terminal surface (401). The first current collector (500) may be connected to the first terminal surface (401) and the first non-removable portion (111). Accordingly, the first current collector (500) may function as a component providing an electrical connection between the electrode assembly (100) and the terminal (400). In this embodiment, the first current collector (500) may function as an anode current collector plate.

[0148] FIG. 3 is a perspective view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention, FIG. 4 is a plan view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention, FIG. 5 is an enlarged view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention, and FIG. 6 is a cross-sectional view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention.

[0149] Referring to FIGS. 3 to 6, the first current collector (500) according to the present embodiment includes a first plate (510), a second plate (520), a fuse hole (530), a first bridge (540), and a second bridge (550).

[0150] The first plate (510) is positioned facing the terminal (400) and can be connected to the terminal (400).

[0151] The first plate (510) according to the present embodiment may be the central portion of the first current collector (500) that is positioned to face directly along the first direction with the first terminal surface (401) of the terminal (400) within the entire area of ​​the first current collector (500). The first plate (510) may have a circular cross-section and a disc shape. However, the cross-sectional shape of the first plate (510) is not limited to this, and the design can be changed to various shapes such as polygons or ellipses. The central axis of the first plate (510) may be positioned coaxially with the central axis of the can (201).

[0152] The area of ​​the first plate (510) perpendicular to the first direction may be larger than the area of ​​the first terminal surface (401) perpendicular to the first direction. That is, a portion of the area of ​​the second collector surface (502) placed in the area where the first plate (510) is formed within the entire second collector surface (502) may be larger than the area of ​​the first terminal surface (401).

[0153] The upper surface of the first plate (510) may come into contact with the first terminal surface (401). The first plate (510) may be fixed to the first terminal surface (401) by laser welding or the like.

[0154] The second plate (520) is spaced apart from the first plate (510) and can be connected to the electrode assembly (100).

[0155] The second plate (520) according to the present embodiment may be formed to have a ring shape with a hollow formed in the center. The diameter (D2) of the second plate (520) may be formed to be larger than the diameter of the first plate (510). The second plate (520) may be arranged to form a concentric circle with the first plate (510). The second plate (520) may be arranged to completely surround the perimeter area of ​​the first plate (510). The outer surface of the second plate (520) may be arranged at a predetermined distance from the inner surface of the first plate (510). The thickness of the second plate (520) may be formed to be the same as the thickness (t0) of the first plate (510), or alternatively, it is also possible to form it differently from the thickness (t0) of the first plate (510).

[0156] The area of ​​the second plate (520) may be equal to the area of ​​the electrode assembly (100) perpendicular to the first direction, or smaller than the area of ​​the electrode assembly (100) perpendicular to the first direction.

[0157] The lower surface of the second plate (520) may come into contact with the end of the first blank portion (111) of the electrode assembly (100). The second plate (520) and the first blank portion (111) may be electrically or mechanically connected by laser welding, etc. For example, the end of the first blank portion (111) may be bent in a direction parallel to the lower surface of the second plate (520) and connected to the lower surface of the second plate (520) by welding, etc.

[0158] A fuse hole (530) may be placed between the first plate (510) and the second plate (520). The fuse hole (530) may function as a configuration that reduces the current travel area between the first plate (510) and the second plate (520) and concentrates the current to the first bridge (540) and the second bridge (550) described later.

[0159] The fuse hole (530) according to the present embodiment may be exemplified as an empty space formed between the first plate (510) and the second plate (520) as the first plate (510) and the second plate (520) are spaced apart from each other. The fuse hole (530) may be formed to have the shape of a ring, with the inner surface and the outer surface being surrounded by the outer surface of the first plate (510) and the inner surface of the second plate (520), respectively. The cross-sectional shape of the fuse hole (530) is not limited to the circular shape shown in FIGS. 3 to 5, and can be designed to have various shapes such as polygons and ellipses.

[0160] The first bridge (540) and the second bridge (550) can be placed inside the fuse hole (530). The first bridge (540) and the second bridge (550) can each be connected to the first plate (510) and the second plate (520), respectively. The first bridge (540) and the second bridge (550) can function as a configuration that cuts off the electrical connection between the first plate (510) and the second plate (520) by their own resistance when an overcurrent flows into the first current collector (500).

[0161] According to the present embodiment, the first bridge (540) and the second bridge (550) may be formed to have a rod shape in which the longitudinal direction is arranged parallel to the radial direction of the first current collector (500). The ends of the first bridge (540) and the second bridge (550) may be connected to the outer surface of the first plate (510) and the inner surface of the second plate (520), respectively. Accordingly, the current movement area between the first plate (510) and the second plate (520) is reduced to within the area range of the first bridge (540) and the second bridge (550), so that when an overcurrent flows into the first current collector (500), the electrical connection between the first plate (510) and the second plate (520) can be quickly cut off.

[0162] The first bridge (540) and the second bridge (550) may be spaced apart from each other along the circumferential direction centered on the central axis of the first plate (510). For example, the angle between the first bridge (540) and the second bridge (550) centered on the central axis of the first plate (510) may be 180°.

[0163] The sum (W1+W2) of the width (W1) of the first bridge (540) and the width (W2) of the second bridge (550) may be equal to or smaller than the diameter (D1) of the first plate (510). Accordingly, the first current collector (500) can maintain the current movement area between the first plate (510) and the second plate (520) smaller than the area of ​​the first plate (510), thereby ensuring smooth fusing performance.

[0164] In the following, the width (W1) of the first bridge (540) and the width (W2) of the second bridge (550) are described as widths parallel to the Y-axis based on FIG. 4. However, the width (W1) of the first bridge (540) and the width (W2) of the second bridge (550) are not limited to this, and it is also possible to mean widths on an arc centered on the central axis of the first plate (510) when the shapes of the first bridge (540) and the second bridge (550) have the shape of an arc.

[0165] In this embodiment, the diameter (D1) of the first plate (510) may be 8 mm or less. The width (W1) of the first bridge (540) and the width (W2) of the second bridge (550) may be 1 mm or more and 4 mm or less. The width (W1) of the first bridge (540) and the width (W2) of the second bridge (550) may be the same as each other.

[0166] In this embodiment, the length (L1) of the first bridge (540) and the length (L2) of the second bridge (550) parallel to the radial direction of the first current collector (500) may be 0.5 mm or more and 4 mm or less. The length (L1) of the first bridge (540) and the length (L2) of the second bridge (550) may be the same as each other.

[0167] In this embodiment, the thickness (t1) of the first bridge (540) and the thickness (t2) of the second bridge (550) in the first direction, i.e., parallel to the Z-axis, may be equal to or smaller than the thickness (t0) of the first plate (510). The thickness (t1) of the first bridge (540) and the thickness (t2) of the second bridge (550) may be 0.1 mm or more and 1 mm or less. The thickness (t1) of the first bridge (540) and the thickness (t2) of the second bridge (550) may be equal to each other.

[0168] In this embodiment, the ratio of the sum of the areas of the first bridge (540) and the second bridge (550) to the area of ​​the fuse hole (530) may be 0.05 or more and 0.3 or less. Here, the areas of the fuse hole (530), the first bridge (540), and the second bridge (550) may refer to the areas on the XY plane based on FIG. 4. The area of ​​the fuse hole (530) may refer to the value obtained by subtracting the areas of the first plate (510), the first bridge (540), and the second bridge (550) from the area of ​​the inner diameter portion of the second plate (520). The area of ​​the first bridge (540) may be the value obtained by multiplying the length (L1) of the first bridge (540) by the width (W1) of the first bridge (540), and the area of ​​the second bridge (550) may be the value obtained by multiplying the length (L2) of the second bridge (550) by the width (W2) of the second bridge (550).

[0169] If the ratio of the sum of the areas of the first bridge (540) and the second bridge (550) to the area of ​​the fuse hole (530) is less than 0.05, the cell resistance of the secondary battery (2) may increase excessively, and the performance of the secondary battery (2) may be degraded.

[0170] If the ratio of the sum of the areas of the first bridge (540) and the second bridge (550) to the area of ​​the fuse hole (530) is greater than 0.3, the first bridge (540) and the second bridge (550) may not melt smoothly when an overcurrent occurs, and the current blocking performance may be reduced.

[0171] The secondary battery (2) according to the present embodiment may further include a second current collector (600).

[0172] The second current collector (600) is positioned between the electrode assembly (100) and the cap plate (300) and can be connected to the electrode assembly (100). The second current collector (600) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0173] The second current collector (600) according to the present embodiment may include a flat portion (610) facing the other side of the electrode assembly (100) on which the second non-removable portion (121) protrudes, and an extension portion (620) extending from the flat portion (610).

[0174] One side of the planar portion (610) facing the other side of the electrode assembly (100) can be connected to the second non-planar portion (121). Accordingly, in this embodiment, the second current collector (600) can function as a negative current collector plate. The end of the second non-planar portion (121) is bent in a direction parallel to the planar portion (610) and can be connected to one side of the planar portion (610) by welding or the like. The bending direction of the second non-planar portion (121) may be a direction toward the winding axis (C) of the electrode assembly (100).

[0175] The extension portion (620) may extend from the edge of the flat portion (610) toward the cap plate (300). The extension portion (620) may come into contact with the inner surface of the beading portion (204). The extension portion (620) may be rounded or bent along the beading portion (204). The extension portion (620) may be connected to the beading portion (204) by welding or the like. Accordingly, the case (200) and the second electrode plate (120) are electrically connected, and the closure portion (203) may function as a negative terminal.

[0176] The extension portion (620) may be formed in multiple numbers. The multiple extension portions (620) may be spaced apart from each other along the edge of the planar portion (610).

[0177] However, the secondary battery (2) according to the present embodiment is not limited thereto, and it is also possible for the second non-removable portion (121) of the electrode assembly (100) to be directly connected to the cap plate (300).

[0178] Below, a secondary battery (2) according to the second embodiment of the present invention will be described.

[0179] The secondary battery (2) according to the present embodiment may be configured to differ only in the detailed configuration of the first bridge (540) and the second bridge (550) from the secondary battery (2) according to the first embodiment of the present invention.

[0180] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configurations of the first bridge (540) and the second bridge (550), which are different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0181] For the remaining configuration of the secondary battery (2) according to this embodiment, the description of the secondary battery (2) according to the first embodiment of the present invention may be applied as is.

[0182] FIG. 7 is a plan view schematically showing the configuration of the first bridge and the second bridge according to the second embodiment of the present invention.

[0183] Referring to FIG. 7, the width (W1) of the first bridge (540) and the width (W2) of the second bridge (550) according to the present embodiment may be different from each other. For example, the width (W2) of the second bridge (550) may be larger than the width (W1) of the first bridge (540). Accordingly, the first bridge (540) and the second bridge (550) have different resistance values, thereby enabling sequential breaking or melting operations when an overcurrent occurs. Accordingly, the secondary battery (2) according to the present embodiment can more precisely control the timing at which the current is cut off when an overcurrent occurs by setting the widths of the first bridge (540) and the second bridge (550) differently.

[0184] In this embodiment, the difference (W2-W1) between the width (W2) of the second bridge (550) and the width (W1) of the first bridge (540) may be 0.1 mm or more and 1 mm or less.

[0185] If the difference (W2-W1) between the width (W2) of the second bridge (550) and the width (W1) of the first bridge (540) is less than 0.1 mm, the sequential breaking of the first bridge (540) and the second bridge (550) may not be smooth.

[0186] If the difference (W2-W1) between the width (W2) of the second bridge (550) and the width (W1) of the first bridge (540) is greater than 1 mm, the resistance value of the first bridge (540) becomes excessively high, and the first bridge (540) may break even with small heat generation.

[0187] Below, the operation process of the secondary battery (2) according to the third embodiment of the present invention will be explained.

[0188] FIGS. 8 and 9 are diagrams schematically illustrating the operation process of a secondary battery according to a second embodiment of the present invention.

[0189] Referring to FIGS. 8 and 9, when a short circuit or the like occurs in the secondary battery (2), an overcurrent flows into the first current collector (500), and the temperature of the first current collector (500) rises due to the inherent resistance of the first current collector (500).

[0190] As the width (W1) of the first bridge (540) is formed to be smaller than the width (W2) of the second bridge (550), the first bridge (540) has a relatively higher resistance value than the second bridge (550), and the temperature of the first bridge (540) rises faster than the temperature of the second bridge (550).

[0191] As the temperature of the first bridge (540) rises above the set temperature, the first bridge (540) is melted first.

[0192] After the first bridge (540) is melted, the current between the first plate (510) and the second plate (520) is concentrated in the second bridge (550), and the temperature of the second bridge (550) increases rapidly.

[0193] Afterwards, as the temperature of the second bridge (550) rises above the set temperature, the second bridge (550) is secondarily melted, and the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0194] Below, a secondary battery (2) according to the third embodiment of the present invention will be described.

[0195] The secondary battery (2) according to the present embodiment may be configured to differ only in the detailed configuration of the first bridge (540) and the second bridge (550) from the secondary battery (2) according to the first embodiment of the present invention.

[0196] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configurations of the first bridge (540) and the second bridge (550), which are different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0197] For the remaining configuration of the secondary battery (2) according to this embodiment, the description of the secondary battery (2) according to the first embodiment of the present invention may be applied as is.

[0198] FIG. 10 is a plan view schematically showing the configuration of the first bridge and the second bridge according to the third embodiment of the present invention, and FIG. 11 is an enlarged view schematically showing the configuration of the first bridge and the second bridge according to the third embodiment of the present invention.

[0199] Referring to FIGS. 10 and 11, the length (L1) of the first bridge (540) and the length (L2) of the second bridge (550) according to the present embodiment may be different from each other. For example, the length (L2) of the second bridge (550) may be smaller than the length (L1) of the first bridge (540). Accordingly, the first bridge (540) and the second bridge (550) have different resistance values, thereby enabling sequential breaking or melting operations when an overcurrent occurs. Accordingly, the secondary battery (2) according to the present embodiment can more precisely control the timing at which the current is cut off when an overcurrent occurs by setting the lengths of the first bridge (540) and the second bridge (550) differently.

[0200] In this embodiment, the difference (L2-L1) between the length (L2) of the second bridge (550) and the length (L1) of the first bridge (540) may be 0.1 mm or more and 1 mm or less.

[0201] If the difference (L2-L1) between the length (L2) of the second bridge (550) and the length (L1) of the first bridge (540) is less than 0.1 mm, the sequential breaking of the first bridge (540) and the second bridge (550) may not be smooth.

[0202] If the difference (L2-L1) between the length (L2) of the second bridge (550) and the length (L1) of the first bridge (540) is greater than 1 mm, the resistance value of the first bridge (540) becomes excessively high, and the first bridge (540) may break even with small heat generation.

[0203] Below, the operation process of the secondary battery (2) according to the third embodiment of the present invention will be explained.

[0204] FIGS. 12 and 13 are diagrams schematically illustrating the operation process of a secondary battery according to a third embodiment of the present invention.

[0205] Referring to FIG. 12 and FIG. 13, when a short circuit or the like occurs in the secondary battery (2), an overcurrent flows into the first current collector (500), and the temperature of the first current collector (500) rises due to the inherent resistance of the first current collector (500).

[0206] As the length (L1) of the first bridge (540) is formed to be larger than the length (L2) of the second bridge (550), the first bridge (540) has a relatively higher resistance value than the second bridge (550), and the temperature of the first bridge (540) rises faster than the temperature of the second bridge (550).

[0207] As the temperature of the first bridge (540) rises above the set temperature, the first bridge (540) is melted first.

[0208] After the first bridge (540) is melted, the current between the first plate (510) and the second plate (520) is concentrated in the second bridge (550), and the temperature of the second bridge (550) increases rapidly.

[0209] Afterwards, as the temperature of the second bridge (550) rises above the set temperature, the second bridge (550) is secondarily melted, and the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0210] Hereinafter, a secondary battery (2) according to the fourth embodiment of the present invention will be described.

[0211] The secondary battery (2) according to the present embodiment may be configured to differ only in the detailed configuration of the first bridge (540) and the second bridge (550) from the secondary battery (2) according to the first embodiment of the present invention.

[0212] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configurations of the first bridge (540) and the second bridge (550), which are different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0213] For the remaining configuration of the secondary battery (2) according to this embodiment, the description of the secondary battery (2) according to the first embodiment of the present invention may be applied as is.

[0214] FIG. 14 is a cross-sectional view schematically showing the configuration of the first bridge and the second bridge according to the fourth embodiment of the present invention.

[0215] Referring to FIG. 14, the thickness (t1) of the first bridge (540) and the thickness (t2) of the second bridge (550) according to the present embodiment may be different from each other. For example, the thickness (t2) of the second bridge (550) may be greater than the thickness (t1) of the first bridge (540). Accordingly, the first bridge (540) and the second bridge (550) have different resistance values, thereby enabling sequential breaking or melting operations when an overcurrent occurs. Accordingly, the secondary battery (2) according to the present embodiment can more precisely control the timing at which the current is cut off when an overcurrent occurs by setting the thicknesses of the first bridge (540) and the second bridge (550) differently.

[0216] In this embodiment, the difference (t2-t1) between the thickness (t2) of the second bridge (550) and the thickness (t1) of the first bridge (540) may be 0.1 mm or more and 1 mm or less.

[0217] If the difference (t2-t1) between the thickness (t2) of the second bridge (550) and the thickness (t1) of the first bridge (540) is less than 0.1 mm, the sequential breaking of the first bridge (540) and the second bridge (550) may not occur smoothly.

[0218] If the difference (t2-t1) between the thickness (t2) of the second bridge (550) and the thickness (t1) of the first bridge (540) is greater than 1 mm, the resistance value of the first bridge (540) becomes excessively high, and the first bridge (540) may break even with small heat generation.

[0219] Below, the operation process of the secondary battery (2) according to the fourth embodiment of the present invention will be explained.

[0220] FIGS. 15 and 16 are diagrams schematically illustrating the operation process of a secondary battery according to the fourth embodiment of the present invention.

[0221] Referring to FIGS. 15 and 16, when a short circuit or the like occurs in the secondary battery (2), an overcurrent flows into the first current collector (500), and the temperature of the first current collector (500) rises due to the inherent resistance of the first current collector (500).

[0222] As the thickness (t1) of the first bridge (540) is formed to be greater than the thickness (t2) of the second bridge (550), the first bridge (540) has a relatively higher resistance value than the second bridge (550), and the temperature of the first bridge (540) rises faster than the temperature of the second bridge (550).

[0223] As the temperature of the first bridge (540) rises above the set temperature, the first bridge (540) is melted first.

[0224] After the first bridge (540) is melted, the current between the first plate (510) and the second plate (520) is concentrated in the second bridge (550), and the temperature of the second bridge (550) increases rapidly.

[0225] Afterwards, as the temperature of the second bridge (550) rises above the set temperature, the second bridge (550) is secondarily melted, and the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0226] Below, a secondary battery (2) according to the fifth embodiment of the present invention will be described.

[0227] The secondary battery (2) according to the present embodiment may be configured to differ only in the detailed configuration of the secondary battery (2) according to the first embodiment of the present invention and the first current collector (500).

[0228] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the first current collector (500), which is different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0229] For the remaining configuration of the secondary battery (2) according to this embodiment, the description of the secondary battery (2) according to the first embodiment of the present invention may be applied as is.

[0230] FIG. 17 is a plan view schematically showing the configuration of a first current collector member according to the fifth embodiment of the present invention.

[0231] Referring to FIG. 17, the first current collector (500) according to the present embodiment may further include a notch (560).

[0232] The notch (560) can be formed concavely on the inner side of the first bridge (540). The notch (560) can function as a configuration that relatively reduces the current flow area of ​​the first bridge (540) compared to the second bridge (550). Accordingly, the notch (560) can induce the first bridge (540) to melt in priority over the second bridge (550) when an overcurrent flows into the first current collector (500).

[0233] FIG. 18 is an enlarged view schematically showing the configuration of a notch according to the fifth embodiment of the present invention.

[0234] Referring to FIGS. 17 and 18, the notch (560) according to the present embodiment may have the shape of a groove formed concavely along the width direction of the first bridge (540) from the side of the first bridge (540).

[0235] The notch (560) may be formed to narrow in width toward the end. For example, as shown in FIG. 18, the notch (560) may have a roughly triangular cross-sectional shape. Accordingly, stress concentration occurs in the end region of the notch (560), allowing the first bridge (540) to be cut more quickly. However, the cross-sectional shape of the notch (560) is not limited to this, and the design can be changed to various shapes such as a trapezoid or a semicircle.

[0236] The notches (560) may be provided in multiple numbers. Multiple notches (560) may be symmetrically arranged on both sides of the first bridge (540). For example, the notches (560) may be formed as a pair, and the pair of notches (560) may be arranged facing each other on both sides of the first bridge (540). Accordingly, the notches (560) can cause the first bridge (540) to melt uniformly across the width direction when an overcurrent flows into the first current collector (500). The number and arrangement of the notches (560) are not limited to the above-described details and can be modified in various ways.

[0237] Below, the operation process of the secondary battery (2) according to the fifth embodiment of the present invention will be explained.

[0238] FIGS. 19 and 20 are diagrams schematically illustrating the operation process of a secondary battery according to the fifth embodiment of the present invention.

[0239] Referring to FIG. 19 and FIG. 20, when a short circuit or the like occurs in the secondary battery (2), an overcurrent flows into the first current collector (500), and the temperature of the first current collector (500) rises due to the inherent resistance of the first current collector (500).

[0240] As a notch (560) is formed in the first bridge (540), the first bridge (540) has a relatively higher resistance value than the second bridge (550), and the temperature of the first bridge (540) rises faster than the temperature of the second bridge (550).

[0241] As the temperature of the first bridge (540) rises above the set temperature, the first bridge (540) is melted first.

[0242] After the first bridge (540) is melted, the current between the first plate (510) and the second plate (520) is concentrated in the second bridge (550), and the temperature of the second bridge (550) increases rapidly.

[0243] Afterwards, as the temperature of the second bridge (550) rises above the set temperature, the second bridge (550) is secondarily melted, and the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0244] Below, a secondary battery (2) according to the 6th embodiment of the present invention will be described.

[0245] The secondary battery (2) according to the present embodiment may be configured to differ only in the detailed configuration of the secondary battery (2) according to the first embodiment of the present invention and the first current collector (500).

[0246] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the first current collector (500), which is different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0247] For the remaining configuration of the secondary battery (2) according to this embodiment, the description of the secondary battery (2) according to the first embodiment of the present invention may be applied as is.

[0248] FIG. 21 is a plan view schematically showing the configuration of a first current collector member according to the sixth embodiment of the present invention.

[0249] Referring to FIG. 21, the first current collector (500) according to the present embodiment may further include an insulating member (570).

[0250] The insulating member (570) can function as a configuration that relatively increases the melting speed of the first bridge (540) by blocking heat generated in the first bridge (540) from being released to the outside. Accordingly, the insulating member (570) can induce the first bridge (540) to melt before the second bridge (550) when an overcurrent flows into the first current collector (500).

[0251] FIG. 22 is a cross-sectional view schematically showing the configuration of an insulating member according to the 6th embodiment of the present invention.

[0252] Referring to FIGS. 21 and 22, the insulating member (570) may be formed to have a roughly sheet shape. The insulating member (570) may be arranged to completely wrap around the outer surface of the first bridge (540). An adhesive or the like may be applied to the inner surface of the insulating member (570) to fix the insulating member (570) to the outer surface of the first bridge (540). The insulating member (570) may be configured to include an insulating material such as polyethylene, urethane, epoxy, etc.

[0253] The length of the insulating member (570) may be greater than the length (L1) of the first bridge (540). Accordingly, the insulating member (570) can block the release of heat generated from the first bridge (540) along the entire length direction of the first bridge (540).

[0254] Below, the operation process of the secondary battery (2) according to the 6th embodiment of the present invention will be explained.

[0255] FIGS. 23 and 24 are diagrams schematically illustrating the operation process of a secondary battery according to the 6th embodiment of the present invention.

[0256] Referring to FIG. 23 and FIG. 24, when a short circuit or the like occurs in the secondary battery (2), an overcurrent flows into the first current collector (500), and the temperature of the first current collector (500) rises due to the inherent resistance of the first current collector (500).

[0257] As an insulating member (570) is placed on the outer surface of the first bridge (540), heat generated from the first bridge (540) is not released to the outside, and the temperature of the first bridge (540) rises faster than the temperature of the second bridge (550).

[0258] As the temperature of the first bridge (540) rises above the set temperature, the first bridge (540) is melted first.

[0259] After the first bridge (540) is melted, the current between the first plate (510) and the second plate (520) is concentrated in the second bridge (550), and the temperature of the second bridge (550) increases rapidly.

[0260] Afterwards, as the temperature of the second bridge (550) rises above the set temperature, the second bridge (550) is secondarily melted, and the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0261] Below, a secondary battery (2) according to the seventh embodiment of the present invention will be described.

[0262] The secondary battery (2) according to the present embodiment may be configured to differ only in the detailed configuration of the secondary battery (2) according to the first embodiment of the present invention and the first current collector (500).

[0263] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the first current collector (500), which is different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0264] For the remaining configuration of the secondary battery (2) according to this embodiment, the description of the secondary battery (2) according to the first embodiment of the present invention may be applied as is.

[0265] FIG. 25 is a plan view schematically showing the configuration of a first current collector member according to the seventh embodiment of the present invention.

[0266] Referring to FIG. 25, the first current collector (500) according to the present embodiment may further include a third bridge (580).

[0267] The third bridge (580) can be placed inside the fuse hole (530). The third bridge (580) can be placed spaced apart from the first bridge (540) and the second bridge (550). The third bridge (580) can perform the fusing function of the first current collector (500) separately from the first bridge (540) and the second bridge (550).

[0268] FIG. 26 is an enlarged view schematically showing the configuration of a third bridge according to the seventh embodiment of the present invention.

[0269] Referring to FIGS. 25 and 26, the third bridge (580) according to the present embodiment may be formed to have a rod shape in which the longitudinal direction is arranged parallel to the radial direction of the first current collector (500). Both ends of the third bridge (580) may be connected to the outer surface of the first plate (510) and the inner surface of the second plate (520), respectively. The width, length, and thickness of the third bridge (580) may be formed to be the same as the width, length, and thickness of the first bridge (540) and the second bridge (550).

[0270] The first bridge (540), the second bridge (550), and the third bridge (580) can be spaced apart from each other along the circumferential direction centered on the central axis of the first plate (510).

[0271] The gap (A1) between the first bridge (540) and the second bridge (550) may be smaller than the gap (A2) between the first bridge (540) and the third bridge (580) and the gap (A3) between the second bridge (550) and the third bridge (580). The gap (A2) between the first bridge (540) and the third bridge (580) and the gap (A3) between the second bridge (550) and the third bridge (580) may be the same as each other and may be formed differently within a range larger than the gap (A1) between the first bridge (540) and the second bridge (550).

[0272] Accordingly, in the case where an overcurrent flows into the first current collector (500) of the secondary battery (2) according to the present embodiment, the temperature of the first bridge (540) and the second bridge (550), which are located relatively close to each other, is formed higher than the temperature of the third bridge (580), thereby inducing the preferential melting of the first bridge (540) and the second bridge (550).

[0273] Below, the operation process of the secondary battery (2) according to the seventh embodiment of the present invention will be explained.

[0274] FIGS. 27 and 28 are diagrams schematically illustrating the operation process of a secondary battery according to the seventh embodiment of the present invention.

[0275] Referring to FIGS. 27 and 28, when a short circuit or the like occurs in the secondary battery (2), an overcurrent flows into the first current collector (500), and the temperature of the first current collector (500) rises due to the inherent resistance of the first current collector (500).

[0276] As the gap (A1) between the first bridge (540) and the second bridge (550) is formed to be smaller than the gap (A2) between the first bridge (540) and the third bridge (580) and the gap (A3) between the second bridge (550) and the third bridge (580), the temperature of the first bridge (540) and the second bridge (550) rises faster than the temperature of the third bridge (580).

[0277] As the temperature of the first bridge (540) and the second bridge (550) rises above the set temperature, the first bridge (540) and the second bridge (550) are primarily melted.

[0278] After the first bridge (540) and the second bridge (550) are melted, the current between the first plate (510) and the second plate (520) is concentrated in the third bridge (580), and the temperature of the third bridge (580) increases rapidly.

[0279] Afterwards, as the temperature of the third bridge (580) rises above the set temperature, the third bridge (580) is secondarily melted, and the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0280] Hereinafter, battery packs according to various embodiments of the present invention will be described.

[0281] FIG. 29 is a perspective view schematically showing the configuration of a battery pack according to various embodiments of the present invention, and FIG. 30 is a plan view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0282] Referring to FIG. 29 and FIG. 30, a battery pack according to various embodiments may include a housing (1) and a secondary battery (2).

[0283] The housing (1) forms the general outline of the battery pack and can provide a space in which a secondary battery (2) can be accommodated.

[0284] The housing (1) according to the present embodiment may include a housing body (11) and a cover (12).

[0285] 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.

[0286] 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.

[0287] The secondary battery (2) may be placed inside the housing (1). The secondary battery (2) described below may be any one of the secondary batteries (2) according to the first to seventh embodiments described above.

[0288] Multiple secondary batteries (2) may be provided. Multiple secondary batteries (2) may be arranged inside the housing (1) to form various patterns, such as a grid or a zigzag pattern. Multiple secondary batteries (2) may be arranged side by side. The number of secondary batteries (2) can be varied in design depending on the size, shape, etc. of the housing (1).

[0289] The battery pack according to the present embodiment may further include a bus bar (3).

[0290] The busbar (3) can electrically connect multiple secondary batteries (2). Multiple secondary batteries (2) can be connected in series or in parallel by the busbar (3). For example, the busbar (3) can connect secondary batteries (2) arranged in the same row inside the housing (1) in parallel with each other, and connect secondary batteries (2) arranged in two adjacent rows in series with each other. The busbar (3) can be formed of an electrically conductive material such as copper, aluminum, or nickel.

[0291] The busbar (3) according to the present embodiment may include a main busbar (31), a first branch busbar (32), and a second branch busbar (33).

[0292] The main busbar (31) can be positioned between rows of adjacent secondary batteries (2). Multiple main busbars (31) may be provided. The main busbar (31) may extend in a straight line between rows of secondary batteries (2), or it may be regularly bent in a zigzag shape. Multiple main busbars (31) may be positioned individually between different rows of adjacent secondary batteries (2). Multiple main busbars (31) may be electrically interconnected.

[0293] The first branch bus bar (32) can be extended from the main bus bar (31) toward the terminal (400) of the secondary battery (2) described later. The first branch bus bar (32) can be mechanically and electrically connected to the terminal (400) by laser welding, ultrasonic welding, etc.

[0294] The first branch busbar (32) is seated on the second terminal surface (402) of the terminal (400) and can be mechanically and electrically connected to the second terminal surface (402) by welding or the like. Accordingly, the first branch busbar (32) can function as a positive busbar.

[0295] The first branch busbar (32) may be provided in multiple numbers. The multiple first branch busbars (32) may be individually connected to the terminals (400) of different secondary batteries (2).

[0296] The second branch bus bar (33) can be extended from the main bus bar (31) toward the case (200) of the secondary battery (2) described later. The second branch bus bar (33) can be mechanically and electrically connected to the case (200) by laser welding, ultrasonic welding, etc.

[0297] The second branch busbar (33) is seated on the closed portion (203) of the case (200) and can be mechanically and electrically connected to the closed portion (203) by welding or the like. Accordingly, the second branch busbar (33) can function as a negative busbar.

[0298] The second branch bus bar (33) may be provided in multiple numbers. The multiple second branch bus bars (33) may be individually connected to the cases (200) of different secondary batteries (2).

[0299] 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.

[0300] Therefore, the technical scope of protection of the present invention should be determined by the following patent claims.

Claims

1. Electrode assembly; A case accommodating the above electrode assembly and having an opening and a closing; A cap plate that seals the above-mentioned opening; A terminal penetrating the above-mentioned closure and positioned facing the electrode assembly; and A first current collector member disposed between the electrode assembly and the terminal; comprising The above-mentioned first current collector is, A first plate positioned facing the terminal and connected to the terminal; A second plate spaced apart from the first plate and connected to the electrode assembly; A fuse hole disposed between the first plate and the second plate; and A secondary battery characterized by including a first bridge and a second bridge disposed inside the fuse hole and connected to the first plate and the second plate.

2. In Paragraph 1, A secondary battery characterized in that the sum of the width of the first bridge and the width of the second bridge is less than or equal to the diameter of the first plate.

3. In Paragraph 1, A secondary battery characterized in that the width of the first bridge and the width of the second bridge are 1 mm or more and 4 mm or less.

4. In Paragraph 1, A secondary battery characterized in that the width of the second bridge is greater than the width of the first bridge.

5. In Paragraph 4, A secondary battery characterized in that the difference between the width of the second bridge and the width of the first bridge is 0.1 mm or more and 1 mm or less.

6. In Paragraph 1, A secondary battery characterized in that the lengths of the first bridge and the second bridge are 0.5 mm or more and 4 mm or less.

7. In Paragraph 1, A secondary battery characterized in that the length of the second bridge is smaller than the length of the first bridge.

8. In Paragraph 7, A secondary battery characterized in that the difference between the length of the first bridge and the length of the second bridge is 0.1 mm or more and 1 mm or less.

9. In Paragraph 1, A secondary battery characterized in that the thickness of the first bridge and the second bridge is 0.1 mm or more and 1 mm or less.

10. In Paragraph 1, A secondary battery characterized in that the thickness of the second bridge is greater than the thickness of the first bridge.

11. In Paragraph 1, A secondary battery characterized in that the ratio of the sum of the areas of the first bridge and the second bridge to the area of ​​the fuse hole is 0.05 or more and 0.3 or less.

12. In Paragraph 1, A secondary battery characterized by further including a notch formed concavely inwardly on the first bridge in the first current collector member.

13. In Paragraph 1, A secondary battery characterized by further including an insulating member arranged to surround the first bridge in the first current collector.

14. In Paragraph 1, A secondary battery characterized in that the first current collector further comprises a third bridge spaced apart from the first bridge and the second bridge.

15. In Paragraph 14, A secondary battery characterized in that the gap between the first bridge and the second bridge is smaller than the gap between the first bridge and the third bridge.

16. Housing; and A plurality of secondary batteries disposed inside the above housing; including The above secondary battery is, Electrode assembly; A case accommodating the above electrode assembly and having an opening and a closing; A cap plate that seals the above-mentioned opening; A terminal penetrating the above-mentioned closure and positioned facing the electrode assembly; and A first current collector member disposed between the electrode assembly and the terminal; comprising The above-mentioned first current collector is, A first plate positioned facing the terminal and connected to the terminal; A second plate spaced apart from the first plate and connected to the electrode assembly; A fuse hole disposed between the first plate and the second plate; and A battery pack characterized by including a first bridge and a second bridge disposed inside the fuse hole and connected to the first plate and the second plate.

Images