Secondary battery and battery pack including same

Abstract

The present disclosure relates to a secondary battery and a battery pack including same, and the technical problem to be solved is to provide a secondary battery capable of preventing ignition due to overcurrent, and a battery pack including same. To this end, the present disclosure provides a secondary battery comprising: an electrode assembly; a case accommodating the electrode assembly and having an opening portion and a closing portion; a cap plate for sealing the opening portion; a terminal extending through the closing portion and disposed to face the electrode assembly; and a first current collecting member disposed between the electrode assembly and the terminal, wherein the first current collecting member includes: a first plate disposed to face the terminal and connected to the terminal; a second plate disposed to surround the first plate and connected to the electrode assembly; and a notch disposed between the first plate and the second plate.

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 recent rapid proliferation of battery-powered electronic devices, such as mobile phones, laptops, and electric vehicles, has led to a rapid increase in demand for high-energy density and high-capacity secondary batteries. Accordingly, active research and development is underway to improve the performance of lithium secondary batteries.

[0003] A lithium secondary battery is a battery that includes a positive electrode and a negative electrode that contain active materials capable of intercalating and deintercalating lithium ions, and an electrolyte, and produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated / deintercalated from the positive electrode and negative electrode.

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

[0005] The purpose of the present invention is to provide a secondary battery capable of preventing ignition due to overcurrent and a battery pack including the same.

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

[0007] In order to solve the above technical problem, a secondary battery according to the present invention 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 to face the electrode assembly; and a first current collecting member that is positioned between the electrode assembly and the terminal; wherein the first current collecting member comprises: a first plate that is positioned to face the terminal and is connected to the terminal; a second plate that is positioned to surround the first plate and is connected to the electrode assembly; and a notch that is positioned between the first plate and the second plate.

[0008] The first collector member includes a first collector surface arranged to face the electrode assembly; and a second collector surface arranged to face the terminal; and the notch may be formed concavely from the first collector surface toward the second collector surface.

[0009] The width of the above notch may decrease toward the second collector surface.

[0010] The ratio of the depth of the notch to the thickness of the first collector member may be 0.1 to 0.9.

[0011] The depth of the above notch may be 0.05 mm or more and 0.45 mm or less.

[0012] The depth of the notch may increase or decrease from the first plate toward the second plate.

[0013] The above notch may extend continuously along the perimeter of the first plate.

[0014] The above notch may include a plurality of unit notches arranged along the perimeter of the first plate.

[0015] A plurality of the above unit notches may be arranged at equal intervals.

[0016] The spacing between adjacent pairs of unit notches may be different from the spacing between adjacent pairs of unit notches.

[0017] The first collector member may include a first collector surface facing the electrode assembly; and a second collector surface facing the terminal; and the notch may include a first notch formed concavely from the first collector surface toward the second collector surface; and a second notch formed concavely from the second collector surface toward the first collector surface.

[0018] The first notch and the second notch may be positioned facing each other.

[0019] The first current collector further includes a fuse hole disposed between the first plate and the second plate; and a bridge extending across the fuse hole and connected to the first plate and the second plate; and the notch may be formed in the bridge.

[0020] The longitudinal direction of the above notch is parallel to the width direction of the above bridge, and the length of the above notch may be the same as the width of the above bridge.

[0021] The longitudinal direction of the above notch is parallel to the width direction of the above bridge, and the length of the above notch may be smaller than the width of the above bridge.

[0022] The above notch can be formed symmetrically with respect to the center line of the bridge.

[0023] The above notch includes a first end and a second end spaced apart along the width direction of the bridge, and a distance from the center line of the bridge to the first end and a distance from the center line of the bridge to the second end may be different from each other.

[0024] A battery pack according to the present invention comprises: a housing; a plurality of secondary batteries arranged inside the housing; and a bus bar connecting the plurality of secondary batteries; wherein the secondary battery comprises: an electrode assembly; a case accommodating the electrode assembly and having an opening and a closing portion; a cap plate sealing the opening portion; a terminal penetrating the closing portion and arranged to face the electrode assembly; and a first current collecting member arranged between the electrode assembly and the terminal; wherein the first current collecting member comprises: a first plate arranged to face the terminal and connected to the terminal; a second plate arranged to surround the first plate and connected to the electrode assembly; and a notch arranged between the first plate and the second plate.

[0025] According to the present invention, by forming a notch between a first plate connected to a terminal and a second plate connected to an electrode assembly, when an overcurrent occurs, the electrical connection between the terminal and the electrode assembly can be quickly cut off, and safety accidents due to ignition can be prevented.

[0026] According to the present invention, by relatively reducing the connection area between the first plate and the second plate by the bridge, it is possible to induce the melting of the first current collector member to occur preferentially at the bridge when an overcurrent occurs.

[0027] According to the present invention, by forming a notch in the bridge, the bridge can be cut more quickly.

[0028] According to the present invention, since the notch is arranged to face the electrode assembly, the gap between the melting area of ​​the first current collecting member and the electrode assembly is relatively increased, and thermal damage to the electrode assembly can be prevented.

[0029] According to the present invention, the separation point between the first plate and the second plate can be selectively controlled through the position, shape, etc. of the notch.

[0030] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0031] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0032] FIG. 1 is a perspective view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0033] FIG. 2 is a plan view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0034] Figure 3 is a perspective view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention.

[0035] Figure 4 is a cross-sectional view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention.

[0036] Figure 5 is an enlarged view schematically showing the installation state of the first current collecting member according to the first embodiment of the present invention.

[0037] Figure 6 is a perspective view schematically showing the configuration of a first current collecting member according to a first embodiment of the present invention.

[0038] Figure 7 is a cross-sectional view schematically showing the configuration of a first current collecting member according to a first embodiment of the present invention.

[0039] Figures 8 to 11 are drawings showing variations of the notch illustrated in Figure 7.

[0040] Fig. 12 is a drawing schematically showing the configuration of a notch according to a second embodiment of the present invention.

[0041] Fig. 13 is a plan view schematically showing the configuration of a first current collecting member according to a third embodiment of the present invention.

[0042] Fig. 14 is a plan view schematically showing the configuration of a first current collecting member according to a fourth embodiment of the present invention.

[0043] FIG. 15 is a drawing schematically showing the installation state of the first current collector member according to the fifth embodiment of the present invention.

[0044] Fig. 16 is a perspective view schematically showing the configuration of a first current collector member according to a fifth embodiment of the present invention.

[0045] Fig. 17 is a plan view schematically showing the configuration of a first current collecting member according to a fifth embodiment of the present invention.

[0046] Fig. 18 is a plan view schematically showing the configuration of a first current collecting member according to a sixth embodiment of the present invention.

[0047] Figures 19 and 20 are drawings schematically showing the fuse operation process of the first current collector member according to the sixth embodiment of the present invention.

[0048] Figure 21 is a plan view schematically showing the configuration of a first current collecting member according to the seventh embodiment of the present invention.

[0049] Figures 22 to 24 are drawings schematically showing the fuse operation process of the first current collector member according to the seventh embodiment of the present invention.

[0050] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0051] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0052] Additionally, to facilitate understanding of the invention, the attached drawings are not drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0053] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0054] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0055] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0056] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0057] Additionally, when a component is described as being "on," "connected to," or "coupled to" another component, it should be understood that the components may be directly connected or coupled to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through other components.

[0058] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, the use of "may" when describing embodiments of the present disclosure refers 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 list as a whole and do not modify individual elements in the list.

[0059] When reference is made throughout the specification to “A and / or B,” this means A, B, or A and B, unless otherwise stated, and when reference is made to “C through D,” this means C or more and D or less, unless otherwise stated.

[0060] When phrases 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 A, B, and C," or "at least one selected from A, B, and C," are used to specify a list of elements A, B, and C, the phrases can refer to any suitable combination.

[0061] The term "use" may be considered synonymous with the term "utilize." As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than degrees, and are intended to take into account inherent variations in measured or calculated values ​​that would be recognized by those skilled in the art.

[0062] Although terms such as first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections, 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. Thus, a first element, component, region, layer, or section discussed below could also be termed a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0063] For ease of description, spatially relative terms such as "beneath," "below," "lower," "above," "upper," and the like may be used herein to describe the relationship of one element or feature to another element(s) or feature(s) as depicted in the drawings. It will be understood that spatially relative positions encompass 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 drawings is turned over, an element described as "beneath" or "lower" another element would be understood to be "above" or "upper" the other element. Thus, the term "beneath" can encompass both the above and below orientations.

[0064] The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure.

[0065] FIG. 1 is a perspective view schematically showing the configuration of a battery pack according to various embodiments of the present invention, and FIG. 2 is a plan view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0066] Referring to FIGS. 1 and 2, a battery pack according to various embodiments may include a housing (1), a secondary battery (2), and a bus bar (3).

[0067] The housing (1) forms the outline of the battery pack and can provide a space in which a secondary battery (2) can be accommodated.

[0068] The housing (1) according to the present embodiment may include a housing body (11) and a cover (12).

[0069] The housing body (11) can be formed to have the shape of a box with an empty interior and one open side. The cross-sectional shape of the housing body (11) is not limited to the square shape shown in Fig. 1, and can be designed to have various shapes such as a polygon, circle, or oval.

[0070] The cover (12) is coupled to the housing body (11) and can close the internal space of the housing body (11). For example, the cover (12) is formed to have a shape roughly like a plate and can be 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 coupling methods such as bolting, welding, and fitting.

[0071] A secondary battery (2) can function as a unit structure that stores and supplies power in a battery pack.

[0072] A plurality of secondary batteries (2) may be provided. The plurality of secondary batteries (2) may be arranged in various patterns, such as a grid shape or a zigzag shape, inside the housing (1). The plurality of secondary batteries (2) may be arranged in parallel with each other. The number of secondary batteries (2) may be designed in various ways depending on the size, shape, etc. of the housing (1). The detailed configuration of the secondary battery will be described later.

[0073] The bus bar (3) can electrically connect a plurality of secondary batteries (2). The plurality of secondary batteries (2) can be connected in series or parallel by the bus bar (3). For example, the bus bar (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 bus bar (3) can be formed of an electrically conductive material such as copper, aluminum, or nickel.

[0074] Referring to FIG. 2, the bus bar (3) according to the present embodiment may include a main bus bar (31), a first branch bus bar (32), and a second branch bus bar (33).

[0075] The main bus bar (31) can be arranged between rows of neighboring secondary batteries (2). The main bus bar (31) can be provided in multiple numbers. The main bus bar (31) can extend in a straight line between rows of secondary batteries (2), or alternatively, it can be regularly bent in a zigzag shape. The multiple main bus bars (31) can be individually arranged between different rows of neighboring secondary batteries (2). The multiple main bus bars (31) can be electrically interconnected.

[0076] The first branch bus bar (32) can extend 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, or the like. The first branch bus bar (32) can be provided in multiple pieces. The multiple first branch bus bars (32) can be individually connected to different terminals (400).

[0077] The second branch bus bar (33) can extend 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, or the like. The second branch bus bar (33) can be provided in multiple pieces. The multiple second branch bus bars (33) can be individually connected to the cases (200) of different secondary batteries (2).

[0078] Below, a secondary battery (2) according to various embodiments of the present invention will be described.

[0079] FIG. 3 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, and FIG. 4 is a cross-sectional view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention.

[0080] Referring to FIGS. 3 and 4, 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 collecting member (500).

[0081] Hereinafter, the secondary battery is described as a cylindrical lithium ion secondary battery as an example. However, the present invention is not limited thereto, and the secondary battery may be a lithium polymer battery or a square battery.

[0082] The electrode assembly (100) can function as a unit structure that performs charging and discharging operations of power in a secondary battery.

[0083] 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).

[0084] The electrode assembly (100) may have a wound shape centered on the winding axis (C).

[0085] 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 laminated and wound around the winding axis (C) in a clockwise or counterclockwise direction. Accordingly, the electrode assembly (100) may have an approximate jelly roll shape. The cross-sectional shape of the electrode assembly (100) may be designed to have various shapes, such as an oval or a polygon, in addition to a circle. Here, the winding axis (C) may mean a straight line penetrating the center of the electrode assembly (100).

[0086] The first electrode plate (110) can function as the positive electrode of the electrode assembly (100). The first electrode plate (110) can 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 and does not cause chemical changes in the secondary battery.

[0087] 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 surfaces of the first electrode plate (110), or alternatively, it may be applied to only one surface of the first electrode plate (110).

[0088] As the first electrode plate (110) functions as an anode, the first active material layer may include a cathode active material.

[0089] The cathode active material may be a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound). More specifically, one or more of a composite oxide of lithium and a metal selected from the group consisting of cobalt, manganese, nickel, iron, and combinations thereof may be used.

[0090] For example, the cathode 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.

[0091] The first active material layer may further include a positive electrode conductive material.

[0092] The positive electrode conductive material is used to impart conductivity to the first active material layer, and any material that does not cause chemical changes and is electronically conductive 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 fibers, carbon nanofibers, and carbon nanotubes; metal-based materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0093] The first active material layer may further include a positive electrode binder.

[0094] The positive electrode binder serves to attach the particles constituting the positive electrode active material well to each other and also to attach the positive electrode active material well to the first electrode plate (110).

[0095] Examples of positive binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0096] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0097] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0098] When using an aqueous binder as a positive electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0099] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0100] The first electrode plate (110) may include a first non-coated portion (111) on which the first active material layer is not applied. The first non-coated portion (111) may protrude a predetermined distance from one end of the electrode assembly (100) along the winding axis (C).

[0101] The second electrode plate (120) can function as a cathode of the electrode assembly (100). The second electrode plate (120) can be formed to have the shape of a foil containing a metal material such as copper, copper alloy, nickel, or nickel alloy. The second electrode plate (120) can be arranged to face the first electrode plate (110) at a predetermined distance apart from it.

[0102] The second electrode plate (120) is not particularly limited in type, size, shape, etc., as long as it has conductivity and does not cause chemical changes in the secondary battery.

[0103] 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 surfaces of the second electrode plate (120), or alternatively, it may be applied to only one surface of the second electrode plate (120).

[0104] As the second electrode plate (120) functions as a cathode, the second active material layer may include a cathode active material.

[0105] The negative 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.

[0106] The material capable of reversibly intercalating / deintercalating the lithium ions may include 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 natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0107] 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 can be used.

[0108] As a material capable of doping and dedoping lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-Q alloy (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 a combination thereof. The Sn-based negative electrode active material can be Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0109] 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, the composite may include secondary particles (cores) in which silicon primary particles are assembled, and an amorphous carbon coating layer (shell) positioned on the surface of the secondary particles. The amorphous carbon may also be positioned between the silicon primary particles, such that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0110] The silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0111] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in a mixture with a carbon-based negative electrode active material.

[0112] The second active material layer may further include a negative electrode conductive material and a negative electrode binder.

[0113] The negative electrode conductive material is used to provide conductivity to the second active material layer, and any material that does not cause chemical changes and is electronically conductive can be used. Examples of negative electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0114] The negative electrode binder serves to attach the particles constituting the negative electrode active material well to each other and also to attach the negative electrode active material well to the second electrode plate (120).

[0115] Examples of cathode binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0116] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0117] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0118] When using an aqueous binder as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0119] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0120] The second electrode plate (120) may include a second non-coated portion (121) on which a second active material layer is not applied. The second non-coated portion (121) may protrude a predetermined distance from the other end of the electrode assembly (100) located on the opposite side of the first non-coated portion (111) along the winding axis (C).

[0121] A separator (130) may be placed between the first electrode plate (110) and the second electrode plate (120). The separator (130) may perform a 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).

[0122] As such a separation membrane (130), a multilayer membrane of two or more layers of polyethylene, polypropylene, polyvinylidene fluoride, or these 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.

[0123] The separation membrane (130) may include a porous substrate and a coating layer including an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0124] The above porous substrate may be a polymer film formed of any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyether ketone, polyarylether ketone, 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 thereof.

[0125] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0126] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include inorganic particles selected from, but not limited to, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0127] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0128] The separator (130) may be provided as a pair. The 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). The pair of separators (130) may be wound around the winding axis (C) together with the first electrode plate (110) and the second electrode plate (120).

[0129] The case (200) forms a rough outline of the secondary battery (2) and can accommodate the electrode assembly (100). The case (200) can be provided to be electrically conductive. For example, the case (200) can include at least one material selected from the group consisting of steel, stainless steel, aluminum, and an aluminum alloy.

[0130] The case (200) may include a can (201), an opening (202), and a closing portion (203).

[0131] The can (201) may be formed to have a cylindrical shape with a cross-section that is approximately circular. 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).

[0132] The electrode assembly (100) can be accommodated inside the can (201). The central axis of the can (201) can be arranged to be coaxial with the winding axis (C) of the electrode assembly (100).

[0133] The opening portion (202) and the closing portion (203) may be respectively positioned at both ends of the can (201). The opening portion (202) and the closing portion (203) may be positioned spaced apart from each other along a first direction. The first direction described below may refer to a direction from the opening portion (202) toward the closing portion (203) with reference to FIG. 4 among directions parallel to the central axis of the can (201) and the winding axis (C) of the electrode assembly (100).

[0134] 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.

[0135] The closure part (203) according to the present embodiment may be formed to have a circular shape that is placed at the other end of the can (201) spaced apart from the opening part (202) in the first direction. The outer circumference of the closure part (203) may be formed integrally with the inner circumference of the can (201) to seal the other end of the can (201). For example, the can (201) and the closure part (203) may be formed by a deep drawing process. Alternatively, the closure part (203) may be manufactured separately from the can (201) and the outer circumference may be joined to the inner circumference of the can (201). A through hole may be formed in the center of the closure part (203) to provide a path for inserting a terminal (400) described below.

[0136] The first non-conductive portion (111) of the electrode assembly (100) may be positioned so as to face the closed portion (203) inside the can (201). The second non-conductive portion (121) of the electrode assembly (100) may be positioned so as to face the open portion (202) inside the can (201).

[0137] A case gasket (G3) that electrically insulates the electrode assembly (100) and the closure (203) may be placed between the electrode assembly (100) and the closure (203). The case gasket (G3) may 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).

[0138] The case gasket (G3) according to the present embodiment may be placed between one surface of the electrode assembly (100) from which the first non-conductive portion (111) protrudes and the inner surface of the closing portion (203) arranged to face the inner space of the can (201). The case gasket (G3) may be fixed to the inner surface of the closing portion (203) using an adhesive or the like. The case gasket (G3) may be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like.

[0139] The case (200) according to the present embodiment may further include a beading portion (204).

[0140] The beading portion (204) may refer to a portion of the can (201) that protrudes from the inner circumference of the can (201) toward the central axis of the can (201) among the entire area of ​​the can (201). The beading portion (204) may be formed by pressing the outer circumference of the can (201) from the side adjacent to the opening portion (202). The beading portion (204) may be in contact with the other end of the electrode assembly (100) from which the second non-stick portion (121) protrudes. Accordingly, the beading portion (204) may suppress the electrode assembly (100) from moving or being separated from the inside of the can (201).

[0141] The cap plate (300) can be configured to seal the opening (202) of the case (200).

[0142] The cap plate (300) according to the present embodiment may be formed to have an approximately circular shape. The cap plate (300) may be placed inside the can (201). The cap plate (300) may be placed inside the can (201) to face the other end of the electrode assembly (100) with the beading portion (204) therebetween. One surface of the cap plate (300) may be seated on the beading portion (204). The other surface of the cap plate (300) may be placed to face the external space of the can (201).

[0143] A crimping portion (205) for fixing a cap plate (300) may be formed at one end of the can (201) where the opening portion (202) is formed. The crimping portion (205) according to the present embodiment may be bent from one end of the can (201) and may be positioned to face the other surface of the cap plate (300) which is positioned to face the external space of the can (201).

[0144] 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).

[0145] The cap gasket (G1) according to the present embodiment may be arranged to entirely surround the end of the cap plate (300). The outer surface of the cap gasket (G1) may be press-fixed to the inner surface of the beading portion (204) and the crimping portion (205). The cap gasket (G1) may be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like. Accordingly, the cap gasket (G1) may electrically insulate the cap plate (300) and the case (200), and prevent moisture, foreign substances, etc. from entering between the cap plate (300) and the case (200).

[0146] The crimping portion (205) is positioned to face the other surface of the cap plate (300) with the cap gasket (G1) interposed therebetween, and can press the cap plate (300) toward the beading portion (204) by coming into contact with the cap gasket (G1). Accordingly, the cap plate (300) can be stably fixed on the opening portion (202) side of the case (200).

[0147] The cap plate (300) may be formed of a metal material to secure mechanical rigidity, or alternatively, may be formed of a synthetic resin material that does not have electrical conductivity.

[0148] The cap plate (300) may be provided with a vent (301) that opens when the internal pressure of the can (201) exceeds a set pressure.

[0149] The vent (301) according to the present embodiment may be thinner than other areas of the cap plate (300). For example, the vent (301) may have a notch shape that is concavely formed from one side of the cap plate (300) toward the other side. The vent (301) may be spaced apart from the center of the cap plate (300) and may be formed to have a ring shape that is concentric with the cap plate (300). As another example, the vent (301) may have at least one pattern having a straight or curved shape.

[0150] 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) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0151] In this embodiment, the terminal (400) is electrically connected to the first electrode plate (110) of the electrode assembly (100) by the first current collector (500), and thus can function as a positive terminal of the secondary battery (2). However, the terminal (400) is not limited thereto, and can also be electrically connected to the second electrode plate (120) and function as a negative terminal.

[0152] The terminal (400) according to the present embodiment can penetrate the closure portion (203) of the case (200) along the first direction. More specifically, the terminal (400) can be inserted into the inside of the through hole formed in the central portion of the closure portion (203). The outer circumferential surface of the terminal (400) can be arranged to be spaced apart from the inner circumferential surface of the through hole formed in the central portion of the closure portion (203) by a predetermined distance. The two ends of the terminal (400) can be arranged in the inner space and the outer space of the can (201), respectively.

[0153] The two ends of the terminal (400) arranged in the inner and outer spaces of the can (201) are compressed and deformed by riveting and can be arranged to face the outer and inner surfaces of the closure (203), respectively. Accordingly, the edge area of ​​the terminal (400) can have a cross-sectional shape that is approximately U-shaped. Accordingly, the terminal (400) can be stably fixed to the case (200) while penetrating the closure (203).

[0154] A first terminal surface (401) facing the electrode assembly (100) along a first direction may be formed on one side of a 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.

[0155] A second terminal surface (402) may be formed on the other side of the terminal (400) located in the external space of the can (201) and spaced apart from the first terminal surface (401) in the first direction. The second terminal surface (402) according to the present embodiment may have a plane shape that faces the external space of the can (201) and is 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 from each other based on the closing portion (203).

[0156] The first branch bus bar (32) is mounted 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 bus bar (32) can function as a positive bus bar.

[0157] 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).

[0158] The terminal gasket (G2) according to the present embodiment may be arranged to entirely cover the inner surface of the through hole formed in the closure portion (203) and the outer surface and outer side 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 of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like.

[0159] The first current collecting member (500) is placed between the electrode assembly (100) and the first terminal surface (401) and can be connected to the electrode assembly (100). The first current collecting member (500) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0160] The first current collecting member (500) according to the present embodiment may be disposed between one surface of the electrode assembly (100) from which the first non-conductive portion (111) protrudes and the first terminal surface (401). The first current collecting member (500) may have a circular shape including a first current collecting surface (501) facing the electrode assembly (100) and a second current collecting surface (502) facing the first terminal surface (401). The first current collecting surface (501) and the second current collecting surface (502) may be spaced apart from each other in the first direction and disposed parallel to each other. The first current collecting surface (501) and the second current collecting surface (502) may be perpendicular to the first direction.

[0161] The area of ​​the first current collecting member (500) may be equal to or smaller than the area of ​​one side of the electrode assembly (100). The central axis of the first current collecting member (500) may be coaxial with the winding axis (C) of the electrode assembly (100).

[0162] The first current collecting surface (501) of the first current collecting member (500) is in contact with the first non-stick portion (111) protruding from one surface of the electrode assembly (100) and can be electrically connected to the first electrode plate (110). Accordingly, in the present embodiment, the first current collecting member (500) can function as a positive current collecting plate. An end of the first non-stick portion (111) can be bent in a direction parallel to the first current collecting member (500) and connected to one surface of the first current collecting member (500) by welding or the like. The bending direction of the first non-stick portion (111) can be a direction toward the winding axis (C) of the electrode assembly (100).

[0163] The second collector surface (502) of the first collector member (500) is in contact with the first terminal surface (401) of the terminal (400) and can be electrically connected to the terminal (400). Accordingly, the first collector member (500) can electrically connect the first electrode plate (110) and the terminal (400).

[0164] The detailed configuration of the first collector member (500) will be described later.

[0165] The secondary battery (2) according to the present embodiment may further include a second current collecting member (600).

[0166] The second current collector (600) is placed between the electrode assembly (100) and the cap plate (300) and can be connected to the electrode assembly (100). The second current collector (600) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0167] The second collector member (600) according to the present embodiment may include a flat portion (610) facing the other surface of the electrode assembly (100) from which the second non-conductive portion (121) protrudes, and an extension portion (620) extending from the flat portion (610).

[0168] One side of the flat portion (610) facing the other side of the electrode assembly (100) can be connected to the second non-coated portion (121). Accordingly, in the present embodiment, the second current collecting member (600) can function as a negative electrode current collecting plate. An end of the second non-coated portion (121) can be bent in a direction parallel to the flat portion (610) and connected to one side of the flat portion (610) by welding or the like. The bending direction of the second non-coated portion (121) can be a direction toward the winding axis (C) of the electrode assembly (100).

[0169] The extension portion (620) may extend from the edge of the flat portion (610) toward the cap plate (300). The extension portion (620) may contact the inner surface of the bead portion (204). The extension portion (620) may be rounded or bent along the bead portion (204). The extension portion (620) may be connected to the bead portion (204) by welding or the like. Accordingly, the case (200) and the second electrode plate (120) are electrically connected, and the closing portion (203) may function as a negative terminal.

[0170] The extension portion (620) may be formed in multiple pieces. The multiple extension portions (620) may be arranged spaced apart from each other along the edge of the flat portion (610).

[0171] However, the secondary battery (2) according to the present embodiment is not limited to this, and it is also possible for the second non-conductive portion (121) of the electrode assembly (100) to be directly connected to the cap plate (300).

[0172] FIG. 5 is an enlarged view schematically showing the installation state of the first current collecting member according to the first embodiment of the present invention, FIG. 6 is a perspective view schematically showing the configuration of the first current collecting member according to the first embodiment of the present invention, and FIG. 7 is a cross-sectional view schematically showing the configuration of the first current collecting member according to the first embodiment of the present invention.

[0173] Referring to FIGS. 5 to 7, the first collector member (500) according to the present embodiment includes a first plate (510), a second plate (520), and a notch (530).

[0174] The first plate (510) is placed facing the terminal (400) and can be connected to the terminal (400).

[0175] The first plate (510) according to the present embodiment may be a portion of the first current collecting member (500) that is arranged to directly face the first terminal surface (401) of the terminal (400) along the first direction among the entire area of ​​the first current collecting member (500). The first plate (510) may have a circular cross-section shape. However, the cross-sectional shape of the first plate (510) is not limited thereto, and the design may be changed to various shapes such as a polygon or an oval. 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, the area of ​​a portion of the second current collecting surface (502) arranged in the area where the first plate (510) is formed among the entire second current collecting surface (502) may be larger than the area of ​​the first terminal surface (401).

[0176] The second plate (520) is arranged to surround the first plate (510) and can be connected to the electrode assembly (100).

[0177] The second plate (520) according to the present embodiment may be the remaining area of ​​the first current collecting member (500) excluding the first plate (510) among the entire area of ​​the first current collecting member (500). The second plate (520) may be concentric with the first plate (510) and may have a ring shape that entirely surrounds the circumferential area of ​​the first plate (510). The first plate (510) and the second plate (520) may be connected as one body. For example, the outer circumferential surface of the first plate (510) and the inner circumferential surface of the second plate (520) may be formed to contact each other and form the same plane along the circumferential direction of the first current collecting member (500).

[0178] The notch (530) may be placed between the first plate (510) and the second plate (520). When an overcurrent flows into the first current collector (500), the notch (530) may induce a fuse operation of the first current collector (500) in which the first plate (510) and the second plate (520) are electrically and mechanically separated.

[0179] For example, the notch (530) may be configured to form the thickness of the boundary region between the first plate (510) and the second plate (520) smaller than the thickness of the remaining region of the first current collecting member (500). Here, the boundary region between the first plate (510) and the second plate (520) may mean a portion of the entire region of the first current collecting member (500) that extends a predetermined distance toward the first plate (510) and the second plate (520) along the radial direction of the first current collecting member (500) based on the boundary line between the first plate (510) and the second plate (520). Accordingly, when an overcurrent is introduced into the first collector member (500), the notch (530) increases the amount of heat generated in the boundary region between the first plate (510) and the second plate (520), and induces preferential fracture or melting in the boundary region between the first plate (510) and the second plate (520), thereby blocking the electrical connection between the electrode assembly (100) and the terminal (400).

[0180] The notch (530) according to the present embodiment may have a shape of a groove that is concavely sunken from the surface of the first current collecting member (500) toward the inside of the first current collecting member (500). For example, the notch (530) may be formed concavely from the first current collecting surface (501) toward the second current collecting surface (502), i.e., in the first direction. Accordingly, the notch (530) can prevent thermal damage to the electrode assembly (100) by relatively increasing the gap between the melted portion of the first current collecting member (500) and the electrode assembly (100). However, the notch (530) is not limited thereto, and may also be formed concavely from the second current collecting surface (502) toward the first current collecting surface (501), i.e., in the opposite direction to the first direction.

[0181] The notch (530) may extend continuously along the boundary area of ​​the first plate (510) and the second plate (520). More specifically, the notch (530) may have a ring shape that is concentric with the first plate (510) and the second plate (520) and extends continuously along the circumference of the first plate (510).

[0182] The ratio of the depth (h2) of the notch (530) to the thickness (h1) of the first current collecting member (500) parallel to the first direction may be 0.1 to 0.9. That is, the depth (h2) of the notch (530) may have a size of 10% to 90% of the thickness (h1) of the first current collecting member (500). For example, when the depth (h2) of the notch (530) is 0.5 mm, the depth of the notch (530) may have a size of 0.05 mm or more and 0.45 mm or less.

[0183] The width of the notch (530) perpendicular to the first direction may decrease toward the end, i.e., the second current collecting surface (502). For example, as illustrated in FIG. 7, the cross-section of the notch (530) may have a triangular shape in which the width linearly decreases along the first direction. The end of the notch (530) may be located on the boundary line between the first plate (510) and the second plate (520). Accordingly, when the fuse of the first current collecting member (510) operates, a stress concentration phenomenon occurs in the end region of the notch (530), so that the first plate (510) and the second plate (520) may be quickly separated.

[0184] Figures 8 to 11 are drawings showing variations of the notch illustrated in Figure 7.

[0185] Referring to FIGS. 8 and 9, the cross-section of the notch (530) may have a trapezoidal shape with a width that linearly decreases along the first direction, or may have a semicircle or semi-ellipse shape rounded at a predetermined curvature. Accordingly, the notch (530) can stably separate the first plate (510) and the second plate (520) by relatively increasing the melting area of ​​the first current collecting member (500).

[0186] Referring to Fig. 10, the cross-section of the notch (530) may have a shape in which the width decreases in a multi-step or non-linear manner along the first direction. For example, the notch (530) may include a base notch (530a) that extends from the first collector surface (501) toward the second collector surface (502) to have a trapezoidal cross-section, and an extension notch (530b) that extends from the upper end of the base notch (530a) toward the second collector surface (502) to have a triangular cross-section. The width of the lower end of the extension notch (530b) may be formed to be smaller than the width of the upper end of the base notch (530a).

[0187] Referring to FIG. 11, the depth of the notch (530) parallel to the first direction may increase or decrease from the first plate (510) toward the second plate (520). FIG. 11 illustrates an example in which the depth of the notch (530) increases from the first plate (510) toward the second plate (520). However, the notch (530) is not limited thereto, and may be configured to decrease from the first plate (510) toward the second plate (520). The maximum depth and minimum depth of the notch (530) can be variously designed and changed within a range of 10% to 90% of the thickness (h1) of the first current collecting member (500). Accordingly, the user can vary the separation timing of the first plate (510) and the second plate (520) by adjusting the difference between the maximum depth and the minimum depth of the notch (530).

[0188] Below, a secondary battery (2) according to a second embodiment of the present invention will be described.

[0189] The secondary battery (2) according to the present embodiment can be configured to differ from the secondary battery (2) according to the first embodiment of the present invention only in the detailed configuration of the notch (530).

[0190] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notch (530) that is different from that of the secondary battery (2) according to the first embodiment of the present invention will be described.

[0191] The description of the secondary battery (2) according to the first embodiment of the present invention can be applied as is to the remaining configuration of the secondary battery (2) according to the present embodiment.

[0192] Fig. 12 is a drawing schematically showing the configuration of a notch according to a second embodiment of the present invention.

[0193] Referring to FIG. 12, the notch (530) according to the present embodiment may include a first notch (531) and a second notch (532).

[0194] The first notch (531) may be formed concavely from the first collector surface (501) toward the second collector surface (502), i.e., along the first direction. The first notch (531) may have the same configuration as the notch (530) according to the first embodiment of the present invention described above. The cross-sectional shape of the first notch (531) may have any one of the shapes illustrated in FIGS. 7 to 11.

[0195] The second notch (532) may be formed concavely from the second collector surface (502) toward the first collector surface (501), i.e., in a direction opposite to the first direction. The cross-sectional shape of the second notch (532) may have any of the shapes illustrated in FIGS. 7 to 11. The cross-sectional shapes and depths of the first notch (531) and the second notch (532) may be the same, or may be formed differently.

[0196] The end of the second notch (532) arranged to face the first collector surface (501) may be spaced apart from the end of the first notch (531) arranged to face the second collector surface (502) by a predetermined distance. The end of the first notch (531) and the end of the second notch (532) may be arranged to face each other along the first direction. In this case, since the thickness of the cutting region of the first collector member (500) is reduced by the sum of the respective depths of the first notch (531) and the second notch (532), the processing depths of the first notch (531) and the second notch (532) can be relatively reduced.

[0197] Below, a secondary battery (2) according to a third embodiment of the present invention will be described.

[0198] The secondary battery (2) according to the present embodiment can be configured to differ from the secondary battery (2) according to the first and second embodiments of the present invention only in the detailed configuration of the notch (530).

[0199] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notch (530) that is different from the secondary battery (2) according to the first and second embodiments of the present invention will be described.

[0200] For the remaining configuration of the secondary battery (2) according to the present embodiment, the description of the secondary battery (2) according to the first and second embodiments of the present invention can be applied as is.

[0201] Fig. 13 is a plan view schematically showing the configuration of a first current collecting member according to a third embodiment of the present invention.

[0202] Referring to FIG. 13, the notch (530) according to the present embodiment may extend discontinuously along the perimeter of the first plate (510).

[0203] For example, the notch (530) may include a plurality of unit notches (533). In FIG. 13, the number of unit notches (533) is illustrated as three as an example, but the number of unit notches (533) is not limited thereto, and the design can be changed to various numbers such as two, four, or five.

[0204] Each unit notch (533) according to the present embodiment may have an arc shape that surrounds a portion of the circumference of the first plate (510) with the central axis of the first plate (510) as the center. However, the shape of the unit notch (533) is not limited thereto, and may also have a straight shape.

[0205] Each unit notch (533) may be configured to include a first notch (531) and a second notch (532) that are formed concavely from the first collector surface (501) toward the second collector surface (502) as shown in FIG. 7, or formed concavely from the second collector surface (502) toward the first collector surface (501), or formed concavely in opposite directions from both sides of the first collector member (500) as shown in FIG. 12.

[0206] A plurality of unit notches (533) may be arranged at predetermined intervals along the periphery of the first plate (510). In the present embodiment, the plurality of unit notches (533) may be arranged at equal intervals. That is, the intervals (L1, L2, L3) of a pair of adjacent unit notches (533) may all be the same. Here, the interval of a pair of adjacent unit notches (533) may mean a straight-line distance between one end of one of the unit notches (533) of the pair of adjacent unit notches (533) and the other end of the remaining unit notch (533) facing the one end of the corresponding unit notch (533).

[0207] According to this embodiment, when an overcurrent is applied to the first current collector (500), the fuse operation of the first current collector (500) is sequentially performed in an area where a unit notch (533) is formed and an area where a unit notch (533) is not formed, so that the time at which the first plate (510) and the second plate (520) are completely separated can be relatively increased.

[0208] Below, a secondary battery (2) according to a fourth embodiment of the present invention will be described.

[0209] The secondary battery (2) according to the present embodiment can be configured to differ from the secondary battery (2) according to the third embodiment of the present invention only in the detailed configuration of the unit notch (533).

[0210] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the unit notch (533) that is different from that of the secondary battery (2) according to the third embodiment of the present invention will be described.

[0211] The description of the secondary battery (2) according to the third embodiment of the present invention can be applied as is to the remaining configuration of the secondary battery (2) according to the present embodiment.

[0212] Fig. 14 is a plan view schematically showing the configuration of a first current collecting member according to a fourth embodiment of the present invention.

[0213] Referring to Fig. 14, the plurality of unit notches (533) according to the present embodiment may not be arranged at equal intervals. That is, the interval (L1) between a pair of adjacent unit notches (533) and the interval (L2) between another pair of adjacent unit notches (533) may be formed differently from each other.

[0214] According to this embodiment, the point in time at which the first plate (510) and the second plate (520) are completely separated can be set to a desired point in time by adjusting the spacing (L1, L2, L3) of a pair of adjacent unit notches (533).

[0215] Below, a secondary battery (2) according to a fifth embodiment of the present invention will be described.

[0216] The secondary battery (2) according to the present embodiment may be configured to differ from the secondary battery (2) according to the first and second embodiments of the present invention only in the detailed configuration of the first current collecting member (500).

[0217] 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 and second embodiments of the present invention, will be described.

[0218] For the remaining configuration of the secondary battery (2) according to the present embodiment, the description of the secondary battery (2) according to the first and second embodiments of the present invention can be applied as is.

[0219] FIG. 15 is a drawing schematically showing the installation state of the first current collecting member according to the fifth embodiment of the present invention, FIG. 16 is a perspective view schematically showing the configuration of the first current collecting member according to the fifth embodiment of the present invention, and FIG. 17 is a plan view schematically showing the configuration of the first current collecting member according to the fifth embodiment of the present invention.

[0220] Referring to FIGS. 15 to 17, the first collector member (500) according to the present embodiment may further include a fuse hole (540) and a bridge (550).

[0221] The first plate (510) and the second plate (520) according to the present embodiment may be arranged to be spaced apart from each other. For example, the outer surface of the first plate (510) may be arranged to be spaced apart from the inner surface of the second plate (520) by a predetermined distance.

[0222] The fuse hole (540) according to the present embodiment can 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 (540) can be formed to have a ring shape in which the inner and outer surfaces are surrounded by the outer surface of the first plate (510) and the inner surface of the second plate (520), respectively.

[0223] The bridge (550) extends across the fuse hole (540) and can be connected to the first plate (510) and the second plate (520). The bridge (550) can be melted by heat generation when an overcurrent flows into the first current collector (500) and can function as a configuration that blocks the electrical connection between the first plate (510) and the second plate (520).

[0224] The bridge (550) 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 collecting member (500). The two ends of the bridge (550) may be connected to the outer circumferential surface of the first plate (510) and the inner circumferential surface of the second plate (520), respectively. Accordingly, the connection area of ​​the first plate (510) and the second plate (520) is reduced within the area range of the bridge (550), so that when an overcurrent is introduced into the first current collecting member (500), the first plate (510) and the second plate (520) can be separated more quickly.

[0225] In the present embodiment, a notch (530) may be formed in the bridge (550). Accordingly, the notch (530) may reduce the thickness of a portion of the bridge (550) relatively to the thickness of the remaining portion, thereby enabling the bridge (550) to be cut more quickly.

[0226] The notch (530) may be formed concavely from the first collector surface (501) of the bridge (550) toward the second collector surface (502) of the bridge (550) among the entire first collector surface (501) and second collector surface (502) as shown in FIG. 7, or may be formed concavely from the second collector surface (502) of the bridge (550) toward the first collector surface (501) of the bridge (550), or may be configured to include a first notch (531) and a second notch (532) formed concavely in opposite directions from both sides of the bridge (550) as shown in FIG. 12.

[0227] The longitudinal direction of the notch (530) may be arranged parallel to the width direction of the bridge (550). The notch (530) may include a first end (534) and a second end (535) spaced apart from each other along the width direction of the bridge (550).

[0228] In this embodiment, the length of the notch (530) may be equal to the width (LB) of the bridge (550). Accordingly, the first end (534) and the second end (535) of the notch (530) may penetrate both sides of the bridge (550) spaced apart in the width direction of the bridge (550), respectively.

[0229] Below, a secondary battery (2) according to the sixth embodiment of the present invention will be described.

[0230] The secondary battery (2) according to the present embodiment can be configured to differ from the secondary battery (2) according to the fifth embodiment of the present invention only in the detailed configuration of the notch (530).

[0231] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notch (530) that is different from that of the secondary battery (2) according to the fifth embodiment of the present invention will be described.

[0232] For the remaining configuration of the secondary battery (2) according to the present embodiment, the description of the secondary battery (2) according to the fifth embodiment of the present invention can be applied as is.

[0233] Fig. 18 is a plan view schematically showing the configuration of a first current collecting member according to a sixth embodiment of the present invention.

[0234] Referring to Fig. 18, the length of the notch (530) according to the present embodiment may be smaller than the width (LB) of the bridge (550). Accordingly, when an overcurrent flows into the first current collecting member (500), the notch (530) allows the fuse operation of the bridge (550) to occur sequentially in the area where the notch (530) is formed and the area where the notch (530) is not formed, thereby relatively increasing the time at which the first plate (510) and the second plate (520) are completely separated.

[0235] In the present embodiment, the notch (530) may be formed symmetrically with respect to the center line (CB) of the bridge (550). For example, as illustrated in FIG. 18, the distance (L3) from the center line (CB) of the bridge (550) to the first end (534) may be equal to the distance (L4) from the center line (CB) of the bridge (550) to the second end (535).

[0236] Accordingly, the fuse operation of the bridge (550) can be performed primarily in an area where a notch (530) is formed, and secondarily in an area where a notch (530) is not formed.

[0237] Figures 19 and 20 are drawings schematically showing the fuse operation process of the first current collector member according to the sixth embodiment of the present invention.

[0238] Referring to Fig. 19, when a short circuit 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 resistance of the first current collector (500).

[0239] As the thickness of the bridge (550) is formed smaller in the area where the notch (530) is formed than in the area where the notch (530) is not formed, the temperature of the bridge (550) rises relatively quickly in the area where the notch (530) is formed.

[0240] Accordingly, the area where the notch (530) is formed among the entire area of ​​the bridge (550) is primarily cut.

[0241] Referring to Fig. 20, as the area where the notch (530) is formed among the entire area of ​​the bridge (550) is cut, heat generation of the bridge (550) is concentrated and generated in the area facing the first end (534) and second end (535) of the notch (530).

[0242] Afterwards, the area facing the first end (534) and the second end (535) of the notch (530) among the entire area of ​​the bridge (550) is secondarily cut, and the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0243] Below, a secondary battery (2) according to the seventh embodiment of the present invention will be described.

[0244] The secondary battery (2) according to the present embodiment can be configured to differ from the secondary battery (2) according to the sixth embodiment of the present invention only in the detailed configuration of the notch (530).

[0245] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notch (530) that is different from that of the secondary battery (2) according to the sixth embodiment of the present invention will be described.

[0246] The description of the secondary battery (2) according to the sixth embodiment of the present invention can be applied as is to the remaining configuration of the secondary battery (2) according to the present embodiment.

[0247] Figure 21 is a plan view schematically showing the configuration of a first current collecting member according to the seventh embodiment of the present invention.

[0248] Referring to FIG. 21, the notch (530) according to the present embodiment may be formed asymmetrically with respect to the center line (CB) of the bridge (550). That is, the distance (L3) from the center line (CB) of the bridge (550) to the first end (534) and the distance (L4) from the center line (CB) of the bridge (550) to the second end (535) may be different from each other. For example, as illustrated in FIG. 21, the distance (L3) from the center line (CB) of the bridge (550) to the first end (534) may be smaller than the distance (L4) from the center line (CB) of the bridge (550) to the second end (535).

[0249] Accordingly, the fuse operation of the bridge (550) can be performed primarily in the area where the notch (530) is formed, secondarily in the area facing the first end (534), and thirdly in the area facing the second end (535).

[0250] Figures 22 to 24 are drawings schematically showing the fuse operation process of the first current collector member according to the seventh embodiment of the present invention.

[0251] Referring to Fig. 22, when a short circuit 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 resistance of the first current collector (500).

[0252] As the thickness of the bridge (550) is formed smaller in the area where the notch (530) is formed than in the area where the notch (530) is not formed, the temperature of the bridge (550) rises relatively quickly in the area where the notch (530) is formed.

[0253] Accordingly, the area where the notch (530) is formed among the entire area of ​​the bridge (550) is primarily cut.

[0254] Referring to FIG. 23 and FIG. 24, as the area where the notch (530) is formed among the entire area of ​​the bridge (550) is cut, heat generation of the bridge (550) is concentrated and generated in the area facing the first end (534) and the second end (535) of the notch (530).

[0255] In this case, since the distance (L3) from the center line (CB) of the bridge (550) to the first end (534) is formed to be smaller than the distance (L4) from the center line (CB) of the bridge (550) to the second end (535), the temperature of the area facing the first end (534) of the notch (530) among the entire area of ​​the bridge (550) is formed to be relatively high.

[0256] Accordingly, the area facing the first end (534) of the notch (530) among the entire area of ​​the bridge (550) is secondarily cut, and the area facing the second end (535) of the notch (530) among the entire area of ​​the bridge (550) is thirdly cut.

[0257] As the area facing the second end (535) of the notch (530) among the entire area of ​​the bridge (550) is finally cut, the electrical connection between the first plate (510) and the second plate (520) is completely cut off.

[0258] Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

[0259] Therefore, the technical protection scope of the present invention should be defined by the following patent claims.

Claims

1. Electrode assembly; A case that accommodates the electrode assembly and has an opening and a closing portion; A cap plate that seals the above opening; A terminal penetrating the above-mentioned closure and positioned facing the electrode assembly; and A first current collecting member disposed between the electrode assembly and the terminal; The above first collector member is, A first plate positioned facing the terminal and connected to the terminal; A second plate arranged to surround the first plate and connected to the electrode assembly; and A secondary battery characterized by including a notch disposed between the first plate and the second plate.

2. In paragraph 1, The above first collector member is, A first front surface arranged to face the electrode assembly; and Including a second front surface arranged to face the terminal; A secondary battery characterized in that the notch is formed concavely from the first front surface toward the second front surface.

3. In paragraph 2, A secondary battery characterized in that the width of the notch decreases toward the second collector surface.

4. In paragraph 2, A secondary battery characterized in that the ratio of the depth of the notch to the thickness of the first collector member is 0.1 to 0.

9.

5. In paragraph 2, A secondary battery characterized in that the depth of the above notch is 0.05 mm or more and 0.45 mm or less.

6. In paragraph 2, A secondary battery characterized in that the depth of the notch increases or decreases from the first plate toward the second plate.

7. In paragraph 1, A secondary battery characterized in that the notch extends continuously along the periphery of the first plate.

8. In paragraph 1, A secondary battery characterized in that the notch comprises a plurality of unit notches arranged along the periphery of the first plate.

9. In paragraph 8, A secondary battery characterized in that a plurality of the above unit notches are arranged at equal intervals.

10. In paragraph 8, A secondary battery characterized in that the spacing between adjacent pairs of unit notches and the spacing between adjacent pairs of unit notches are different from each other.

11. In paragraph 1, The above first collector member is, A first front surface arranged to face the electrode assembly; and Including a second front surface arranged to face the terminal; The above notch is, A first notch formed concavely from the first front surface toward the second front surface; and A secondary battery characterized by including a second notch formed concavely from the second front surface toward the first front surface.

12. In paragraph 11, A secondary battery characterized in that the first notch and the second notch are arranged to face each other.

13. In paragraph 1, The above first collector member is, A fuse hole arranged between the first plate and the second plate; and further comprising a bridge extending across the fuse hole and connected to the first plate and the second plate; A secondary battery characterized in that the notch is formed in the bridge.

14. In paragraph 13, The longitudinal direction of the above notch is parallel to the width direction of the above bridge, A secondary battery characterized in that the length of the notch is the same as the width of the bridge.

15. In paragraph 13, The longitudinal direction of the above notch is parallel to the width direction of the above bridge, A secondary battery characterized in that the length of the notch is smaller than the width of the bridge.

16. In paragraph 15, A secondary battery characterized in that the notch is formed symmetrically with respect to the center line of the bridge.

17. In paragraph 15, The above notch includes a first end and a second end spaced apart along the width direction of the bridge, A secondary battery characterized in that the distance from the center line of the bridge to the first end and the distance from the center line of the bridge to the second end are different from each other.

18. In paragraph 1, A secondary battery further comprising a second current collecting member disposed between the electrode assembly and the cap plate.

19. Housing; A plurality of secondary batteries arranged inside the housing; and A bus bar connecting a plurality of the secondary batteries is included; The above secondary battery, electrode assembly; A case that accommodates the electrode assembly and has an opening and a closing portion; A cap plate that seals the above opening; A terminal penetrating the above-mentioned closure and positioned facing the electrode assembly; and A first current collecting member disposed between the electrode assembly and the terminal; The above first collector member is, A first plate positioned facing the terminal and connected to the terminal; A second plate arranged to surround the first plate and connected to the electrode assembly; and A battery pack characterized by including a notch disposed between the first plate and the second plate.

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