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 having a notching part formed at a current collecting plate that serves as an electrical passage, thereby ensuring a flow path for relieving internal pressure when a short circuit occurs. To this end, the present disclosure provides the secondary battery comprising: a case; a cap assembly, which is arranged inside the case, is coupled to an electrode assembly case having an uncoated part, and is arranged to face the electrode assembly; a first current collecting plate coupled to the uncoated part that is arranged between the electrode assembly and the cap assembly; and the notching part which is formed to avoid a welding line between the first current collecting plate and the uncoated part, and which ruptures when internal pressure occurs.

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, and produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated / deintercalated from the positive electrode and the negative electrode.

[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 present invention aims to provide a secondary battery and a battery pack including the same, wherein a notching portion is formed on a current collection plate serving as an electrical passage to secure a flow path for relieving internal pressure in the event of a short circuit.

[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 an embodiment of the present invention for solving the above technical problem comprises: a case; an electrode assembly disposed inside the case and having a non-bonded portion; a cap assembly coupled to the case and disposed facing the electrode assembly; a first current collector plate disposed between the electrode assembly and the cap assembly and coupled to the non-bonded portion; and a notching portion formed by avoiding the welding line between the first current collector plate and the non-bonded portion and rupturing when internal pressure is generated.

[0008] The above notching portion may include a center notch formed in the center of the first current collection plate.

[0009] A center hole may be provided inside the center notch.

[0010] The above center notch can be divided into n equal parts.

[0011] The above notching portion may include a plurality of side notches formed at the edge of the first current collection plate.

[0012] The above side notch may be formed between a plurality of side holes formed in the first current collection plate.

[0013] The above side notch can cover the side hole formed in the first current collection plate.

[0014] The above-mentioned side notch may be in a fan shape that surrounds a plurality of the above-mentioned side holes.

[0015] The above notching portion may be an intaglio groove formed by laser cutting or die stamping.

[0016] The angle of indentation formation of the above notching portion may be 30° to 90°.

[0017] The amount of indentation in the above notching portion may be 50% to 80% relative to the thickness of the first current collector plate.

[0018] The above notching portion may include a center notch formed at the center of the first current collection plate; and a side notch connected to the center notch and formed at the edge of the first current collection plate.

[0019] The center notch is formed in a circular shape, and the side notch can be formed in a bar shape extending in the radial direction of the center notch.

[0020] The center notch is formed in a circular shape, and the side notch can be formed in a fan shape extending in the radial direction of the center notch.

[0021] The above side notches may be formed in multiple numbers extending in the radial direction of the center notch.

[0022] The thickness of the center notch above may be thicker than the thickness of the side notch above.

[0023] The wall thickness of the above-mentioned side notch may be 15% to 30% of the thickness of the above-mentioned first current collection plate.

[0024] The thickness of the side notch above may be 50% or less of the thickness of the center notch above.

[0025] It may include a second current collector plate disposed between the above case and the above electrode assembly.

[0026] 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 may include: a case; an electrode assembly disposed inside the case and having a non-bonded portion; a cap assembly coupled to the case and disposed facing the electrode assembly; a first current collector plate disposed between the electrode assembly and the cap assembly and coupled to the non-bonded portion; and a notching portion formed by avoiding the welding line between the first current collector plate and the non-bonded portion and rupturing when internal pressure is generated.

[0027] According to the present invention, by forming a notching portion on a current collection plate that serves as an electrical passage, a flow path is secured to relieve internal pressure in the event of a short circuit, thereby preventing side rupture and enhancing cell stability quality.

[0028] According to the present invention, a notch is formed in which the flow path for relieving internal pressure is prematurely broken, thereby enabling smooth relief of internal pressure.

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

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

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

[0032] FIG. 2 is a cross-sectional view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention.

[0033] FIG. 3 is an enlarged view of the key parts schematically showing the configuration of a secondary battery according to the first embodiment of the present invention.

[0034] FIG. 4 is a plan view schematically showing the center notch configuration of the first current collection plate according to the first embodiment of the present invention.

[0035] Figure 5 is a cross-sectional view taken along line V-V of Figure 4.

[0036] FIG. 6 is a drawing showing a modified example of the center notch of the first current collection plate according to the first embodiment of the present invention.

[0037] FIG. 7 is a plan view schematically showing the side notch configuration of the first current collection plate according to the second embodiment of the present invention.

[0038] Figure 8 is a cross-sectional view of line VIII-VIII of Figure 7.

[0039] FIG. 9 is a plan view schematically showing the side notch configuration of the first current collection plate according to the third embodiment of the present invention.

[0040] FIG. 10 is a cross-sectional view along line X-X of FIG. 9.

[0041] FIGS. 11 and FIGS. 12 are drawings showing a modified example of the side notch of the first current collection plate according to the third embodiment of the present invention.

[0042] FIG. 13 is a schematic diagram showing the configuration of the notching portion of the first current collection plate according to the fourth embodiment of the present invention.

[0043] FIG. 14 is a cross-sectional view taken along line XIV-XIV of FIG. 13.

[0044] FIG. 15 is a first modified example of the notching portion of the first current collection plate according to the fourth embodiment of the present invention.

[0045] FIG. 16 is a cross-sectional view taken along XVI-XVI of FIG. 15.

[0046] FIG. 17 is a drawing showing a second modified example of the notching portion of the first current collection plate according to the fourth embodiment of the present invention.

[0047] FIG. 18 is a perspective view schematically showing the configuration of a secondary battery according to the fifth embodiment of the present invention.

[0048] FIG. 19 is a cross-sectional view schematically showing the configuration of a secondary battery according to the fifth embodiment of the present invention.

[0049] FIG. 20 is an enlarged view of the key parts schematically showing the configuration of a secondary battery according to the fifth embodiment of the present invention.

[0050] FIG. 21 is a plan view schematically showing the configuration of the notching portion of the first current collection plate according to the fifth embodiment of the present invention.

[0051] FIG. 22 is a cross-sectional view of ⅡⅩⅡ-ⅡⅩⅡ of FIG. 21.

[0052] FIG. 23 is a plan view schematically showing the configuration of the notching portion of the first current collection plate according to the sixth embodiment of the present invention.

[0053] FIG. 24 is a cross-sectional view of ⅡⅩⅣ-ⅡⅩⅣ of FIG. 23.

[0054] FIG. 25 is a drawing showing a modified example of the notching portion of the first current collection plate according to the 6th embodiment of the present invention.

[0055] FIG. 26 is a perspective view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0056] 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 may appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, it should be understood that 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; thus, various equivalents and modifications that can replace them may exist at the time of filing this application. Furthermore, as used in this specification, "comprise" or "include" and / or "comprising" or "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. In addition, when describing embodiments of the present invention, "may" and "may be" may include "one or more embodiments of the present invention."

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0061] 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.

[0062] Furthermore, where it is stated that one component is "connected," "coupled," or "connected" to another component, it should be understood that while said components may be directly connected or connected to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "connected" through another component. Additionally, when it is stated that a part is electrically coupled with another part, this includes not only cases where they are directly connected but also cases where they are connected with an intermediate element in between.

[0063] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise. That is, "and / or" includes any combination or any combination of the enumerated items. "C to D" means C or more and D or less, unless specifically stated otherwise.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0069] Hereinafter, a secondary battery and a battery pack including the same according to various embodiments of the present invention will be described with reference to the attached drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intention or convention of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0070] 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.

[0071] Referring to FIG. 1 and FIG. 2, the secondary battery (2) according to the present embodiment may include a case (100), an electrode assembly (200), a cap assembly (300), a first current collector plate (400), and a notching portion (500).

[0072] In the following description, the secondary battery (2) is described as a cylindrical battery as a lithium-ion secondary battery. However, the present invention is not limited thereto, and the secondary battery (2) may be a lithium polymer battery or a prismatic battery.

[0073] The case (100) can form the general appearance of the secondary battery (2). The case (100) can be provided to be electrically conductive. For example, the case (100) may include at least one material among steel, stainless steel, aluminum, and aluminum alloy. Accordingly, the case (100) can perform a heat dissipation function to protect the electrode assembly (200) from external impact and to release heat associated with the charging and discharging operation of the electrode assembly (200) to the outside.

[0074] The case (100) according to the present embodiment may include a cylindrical side wall portion (110). This may refer to the central axis of the side wall portion (110) of the case (100) described below. Both ends of the side wall portion (110) perpendicular to the central axis of the case (100) may be formed to be open.

[0075] The case (100) may further include a bottom portion (120) that closes the lower portion of the side wall portion (110). The bottom portion (120) according to the present embodiment is formed to have a shape approximately like a disc and may be positioned facing the lower portion of the side wall portion (110). The bottom portion (120) may be positioned perpendicular to the central axis of the case (100). The perimeter surface of the bottom portion (120) may be joined to the lower portion of the side wall portion (110). The bottom portion (120) may be formed integrally with the side wall portion (110) by a drawing process or the like, or alternatively, it may be manufactured separately from the side wall portion (110) and then joined to the side wall portion (110) by welding or the like.

[0076] The case (100) may further include an opening (130) that opens the upper portion of the side wall portion (110). The opening (130) may function as a configuration that provides a path for the electrode assembly (200), described later, to be inserted into the interior of the case (100) in the upper region of the case (100), and provides a space in which the cap assembly (300), described later, can be installed. The opening (130) according to the present embodiment may refer to an empty space surrounded by the upper region of the side wall portion (110) located on the opposite side of the bottom portion (120).

[0077] The case (100) according to the present embodiment may further include a beading portion (140).

[0078] The beading portion (140) may protrude into the interior of the case (100). The beading portion (140) may limit the cap assembly (300), which will be described later, from being inserted into the interior of the case (100) by a set distance or more.

[0079] The beading portion (140) according to the present embodiment may be positioned at the upper end of the side wall portion (110). The central portion of the beading portion (140) may be formed concavely toward the central axis (C). The beading portion (140) may be formed integrally with the side wall portion (110), or alternatively, it may be manufactured separately from the side wall portion (110) and then joined to the side wall portion (110).

[0080] In the following description, the secondary battery (2) according to the present embodiment will be described as including a beading portion (140), but the present invention is not limited thereto, and it is also possible to configure it in a form where the beading portion (140) is omitted.

[0081] The interior of the case (100) can be filled with an electrolyte. The electrolyte can be injected into the interior of the case (100) through the opening (130) of the case (100).

[0082] The electrode assembly (200) can function as a unit structure that performs charging and discharging operations of power in a secondary battery (2). The electrode assembly (200) may include a first electrode (210), a second electrode (220), and a separator (230) disposed between the first electrode (210) and the second electrode (220).

[0083] The electrode assembly (200) can be placed inside the case (100). The electrode assembly (200) can be inserted into the interior of the case (100) through the opening (130) of the case (100).

[0084] The electrode assembly (200) may have a cylindrical shape with a winding hole (201) formed in the center.

[0085] More specifically, the electrode assembly (200) can be wound along a clockwise or counterclockwise direction around the central axis (C) of the winding hole (201) while the first electrode (210), the separator (230), and the second electrode (220) are stacked. Accordingly, the electrode assembly (200) can have a shape roughly like a jelly roll. The cross-sectional shape of the electrode assembly (200) can be designed to have various shapes, such as an ellipse or a polygon, in addition to a circular shape.

[0086] The first electrode (210), the separator (230), and the second electrode (220) can be arranged sequentially in a concentric circle along the radial direction of the electrode assembly (200) from the central axis of the winding hole (201).

[0087] A separator (230) may be disposed within the inner periphery of the electrode assembly (200). Accordingly, the winding hole (201) according to the present embodiment may be an internal space of the electrode assembly (200) formed to be wrapped by the inner surface of the separator (230). The central axis (C) of the winding hole (201) may be positioned coaxially with the central axis of the case (100). Both ends of the winding hole (201) perpendicular to the central axis of the case (100) may be formed to be open.

[0088] The two ends of the first electrode (210), the second electrode (220), and the separator (230), which are parallel to the central axis (C) of the case (100), may be positioned to face the bottom portion (120) and the opening portion (130) of the case (100), respectively.

[0089] The first electrode (210) can function as the positive electrode of the electrode assembly (200). The first electrode (210) 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 (210) are not particularly limited, as long as it is conductive without causing chemical changes in the secondary battery.

[0090] A first active material layer may be applied to at least a portion of the first electrode (210). The first active material layer may be applied to both sides of the first electrode (210), or alternatively, it may be applied to only one side of the first electrode (210).

[0091] As the first electrode (210) functions as a positive electrode, the first active material layer may include a positive electrode active material.

[0092] 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.

[0093] 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, LNCM) 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, LNCM)중 어느 두개 또는 이들을 모두 포함하는 것도 가능하다.

[0094] The first active material layer may further include a positive conductive material.

[0095] 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.

[0096] The first active material layer may further include an anode binder.

[0097] 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 (210).

[0098] Examples of positive binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0099] Examples of 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.

[0100] The 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.

[0101] When using a water-based binder as the anode binder, it may further include a cellulose-based compound capable of imparting viscosity. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be used in a mixture. Na, K, or Li may be used as the alkali metal.

[0102] The 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.

[0103] The second electrode (220) can function as the negative electrode of the electrode assembly (200). The second electrode (220) 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 (220) may be positioned facing the first electrode (210) at a predetermined distance apart.

[0104] The second electrode (220) is not particularly limited in type, size, shape, etc., as long as it is conductive without causing chemical changes in the secondary battery.

[0105] A second active material layer may be applied to at least a portion of the second electrode (220). The second active material layer may be applied to both sides of the second electrode (220), or alternatively, it may be applied to only one side of the second electrode (220).

[0106] As the second electrode (220) functions as a negative electrode, the second active material layer may include a negative active material.

[0107] 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.

[0108] Materials capable of reversibly intercalating / deintercalating lithium ions may include carbon-based negative electrode active materials, such as 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.

[0109] As lithium metal alloys, alloys of lithium and metals 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.

[0110] Si-based negative electrode active materials or Sn-based negative electrode active materials may be used as materials capable of doping and undoping lithium. Si-based negative electrode active materials may be silicon, silicon-carbon composites, SiOx (x = 1 or 2), Si-Q alloys (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.

[0111] A 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. 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.

[0112] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0113] Si-based or Sn-based cathode active materials can be used in combination with carbon-based cathode active materials.

[0114] The second active material layer may further include a cathode conductive material and a cathode binder.

[0115] 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.

[0116] 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 (220).

[0117] Examples of cathode binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0118] Examples of 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.

[0119] The 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.

[0120] When using a water-based binder 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 used in a mixture. Na, K, or Li may be used as the alkali metal.

[0121] The 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.

[0122] A separator (230) may be placed between the first electrode (210) and the second electrode (220). The separator (230) may perform the function of preventing a short circuit between the first electrode (210) and the second electrode (220) while allowing the movement of lithium ions between the first electrode (210) and the second electrode (220).

[0123] As such a separator (230), 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.

[0124] The separator (230) 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.

[0125] 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.

[0126] The organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0127] The inorganic material may include, but is not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0128] 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.

[0129] The cap assembly (300) is coupled to the case (100) and can be positioned facing the electrode assembly (200). The cap assembly (300) can seal the case (100). For example, the cap assembly (300) can be positioned at the upper end of the side wall portion (110), i.e., on the side of the opening (130). The cap assembly (300) can be positioned facing the electrode assembly (200) along a direction parallel to the central axis (C) of the winding hole (201).

[0130] The cap assembly (300) according to the present embodiment may include a cap up (310), a cap down (320), a vent plate (330), and an extension part (340).

[0131] The cap up (310) can form the upper exterior of the cap assembly (300). The cap up (310) can be electrically connected to the first electrode (210) by the cap down (320) and the vent plate (330) described later. The central axis of the cap up (310) can be located coaxially with the central axis (C) of the winding hole (201). The central part of the cap up (310) can protrude outside the case (100). The cap up (310) can be provided with an electrically conductive material such as nickel, aluminum, or copper.

[0132] The cap up (310) according to the present embodiment may include a small diameter portion (311), a large diameter portion (312), and a bridge (313).

[0133] The small diameter portion (311) and the large diameter portion (312) may have the shape of discs with different diameters. The diameter of the small diameter portion (311) may be smaller than the diameter of the large diameter portion (312). The central axis of the small diameter portion (311) and the large diameter portion (312) may be arranged coaxially with the central axis (C) of the winding hole (201). The small diameter portion (311) and the large diameter portion (312) may be arranged facing each other along the first direction. The small diameter portion (311) may be placed above the large diameter portion (312). The small diameter portion (311) may protrude to the outside of the case (100). The large diameter portion (312) may have the shape of a ring with a hollow formed in the center.

[0134] The bridge (313) may be positioned between the small diameter portion (311) and the large diameter portion (312). Both ends of the bridge (313) may be connected to the outer surface of the small diameter portion (311) and the outer surface of the large diameter portion (312), respectively. The bridge (313) may have a curved shape that extends in a curved manner from the small diameter portion (311) toward the large diameter portion (312).

[0135] A cap-up hole (314) may be formed in the cap-up (310) to discharge gas or the like generated inside the case (100) to the outside of the case (100). The cap-up hole (314) according to the present embodiment may have the shape of a hole penetrating the bridge (313) of the cap-up (310). A plurality of cap-up holes (314) may be provided. A plurality of cap-up holes (314) may be arranged at predetermined intervals along the circumferential surface of the central part of the cap-up (310).

[0136] The cap down (320) is positioned facing the cap up (310) and can be electrically connected to the electrode assembly (200).

[0137] The cap down (320) according to the present embodiment may be formed to have a roughly disc shape. The cap down (320) may be placed inside the case (100). The cap down (320) may be placed below the cap up (310). That is, the cap down (320) may be placed between the cap up (310) and the electrode assembly (200). The central axis of the cap down (320) may be placed coaxially with the central axis (C) of the winding hole (201). The upper surface of the cap down (320) may be placed spaced apart from the lower surface of the cap up (310).

[0138] The area of ​​the cap down (320) may be smaller than the cross-sectional area of ​​the electrode assembly (200) perpendicular to the central axis (C) of the winding hole (201). However, the area of ​​the cap down (320) is not limited to this, and it may be equal to or larger than the cross-sectional area of ​​the electrode assembly (200).

[0139] The cap down (320) may be provided with an electrically conductive material such as nickel, aluminum, or copper. The cap down (320) may be electrically connected to the electrode assembly (200). The cap down (320) may be electrically connected to the cap up (310) by the vent plate (330) described later.

[0140] A cap down hole (321) that penetrates the cap down (320) vertically may be formed in the cap down (320). The cap down hole (321) may function as a configuration that provides a path for gases, etc. generated inside the case (100) to pass through the cap down (320) when an overcurrent occurs. The cap down hole (321) may be provided in multiple numbers. The multiple cap down holes (321) may be arranged along a circumference centered on the central axis of the cap down (320).

[0141] A vent plate (330) may be positioned between the cap up (310) and the cap down (320). The vent plate (330) may provide a current conduction path between the cap up (310) and the cap down (320) during normal operation of the secondary battery (2). The vent plate (330) may be made of an electrically conductive material such as nickel, aluminum, or copper.

[0142] The vent plate (330) is deformed by the pressure of the gas generated inside the case (100) when an overcurrent occurs, and can cut off the electrical connection between the cap up (310) and the cap down (320). The vent plate (330) ruptures when the internal pressure of the case (100) rises above a set size, and can open the gas discharge path between the cap up hole (314) and the cap down hole (321).

[0143] The vent plate (330) according to the present embodiment may be formed to have a shape approximately like a disc. The upper and lower sides of the vent plate (330) may be positioned to face the cap-up (310) and cap-down (320), respectively. The lower surface of the vent plate (330) may be positioned to face the cap-down hole (321). The central axis of the vent plate (330) may be positioned coaxially with the central axis (C) of the winding hole (201).

[0144] The vent plate (330) may include a contact portion (331).

[0145] The contact portion (331) according to the present embodiment protrudes from the vent plate (330) toward the cap down (320) and can come into contact with the cap down (320). The contact portion (331) can function as a component that electrically connects the vent plate (330) and the cap down (320). The contact portion (331) can be positioned in the center of the vent plate (330). The central axis of the contact portion (331) can be positioned coaxially with the central axis (C) of the winding hole (201).

[0146] When the vent plate (330) is deformed due to an increase in internal pressure of the case (100), the contact portion (331) can be separated from the cap down (320). Accordingly, when an overcurrent occurs, the electrical connection between the cap down (320) and the vent plate (330) can be cut off.

[0147] A cap insulator (301) may be placed between the vent plate (330) and the cap down (320). The cap insulator (301) can prevent the remaining area of ​​the vent plate (330), excluding the contact portion (331), from coming into direct contact with the cap down (320). Accordingly, the cap insulator (301) can ensure that the electrical connection between the vent plate (330) and the cap down (320) is made only through the contact portion (331) described later.

[0148] The cap insulator (301) according to the present embodiment may be formed to have a hollow ring shape. The central axis of the cap insulator (301) may be located coaxially with the central axis (C) of the winding hole (201) and the central axis of the vent plate (330). The upper surface of the cap insulator (301) may be in contact with the lower surface of the vent plate (330), and the lower surface of the cap insulator (301) may be in contact with the upper surface of the cap down (320). The cap insulator (301) may be formed from an insulating material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0149] The extension (340) extends from the vent plate (330) and can be connected to the cap up (310). The extension (340) can function as a component that supports the vent plate (330) with respect to the cap up (310) and provides an electrical connection between the cap up (310) and the vent plate (330). The extension (340) can be formed from the same material as the vent plate (330). The extension (340) can be formed integrally with the vent plate (330), or alternatively, it is possible to manufacture it separately from the vent plate (330) and then combine it with the vent plate (330).

[0150] The extension part (340) according to the present embodiment may include a support part (341) and a hinge part (342).

[0151] The support member (341) forms one side of the extension member (340) and can be connected to the cap up (310).

[0152] The support member (341) according to the present embodiment may be positioned to surround the end of the cap-up (310), more specifically the edge area of ​​the large diameter portion (312). For example, the support member (341) may have a cross-sectional shape approximately U-shaped. One end of the support member (341) may be in contact with the upper surface of the large diameter portion (312), and the other end of the support member (341) may be bent downward to be in contact with the lower surface of the large diameter portion (312). The support member (341) may be joined to the cap-up (310) by various types of joining methods, such as laser welding, ultrasonic welding, and resistance welding.

[0153] The support member (341) may be positioned to face the beading member (140) along the first direction. For example, the support member (341) may be positioned above the beading member (140). Accordingly, when assembling the secondary battery (2), the beading member (140) may limit the cap assembly (300) from being inserted into the interior of the case (100) by more than a set distance.

[0154] The hinge portion (342) forms the outer surface of the other side of the extension portion (340) and can be positioned between the support portion (341) and the vent plate (330). The hinge portion (342) can function as a configuration that interconnects the support portion (341) and the vent plate (330) and guides the deformation of the vent plate (330) when the internal pressure of the case (100) increases.

[0155] The hinge portion (342) according to the present embodiment has a roughly circular ring shape and can be positioned between the support portion (341) and the vent plate (330). The inner surface of the hinge portion (342) is connected to the vent plate (330), and the outer surface of the hinge portion (342) can be connected to the other end of the support portion (341). The hinge portion (342) can be extended downward in a stepped manner from the outer surface toward the inner surface. For example, the central portion of the hinge portion (342) may have a cross-section bent into an L-shape.

[0156] When an overcurrent occurs, the vent plate (330) may be deformed relative to the hinge portion (342). For example, when the internal pressure of the case (100) increases due to the overcurrent, the gas passing through the cap down hole (321) pressurizes the vent plate (330) upward, and the vent plate (330) may be deformed into a shape in which the central part protrudes upward convexly due to a change in the bending angle of the hinge portion (342).

[0157] The secondary battery (2) according to the present embodiment may further include a vent notch (360).

[0158] The vent notch (360) may be formed concavely from the outer surface of the vent plate (330). The vent notch (360) may function as a component that guides the rupture of the vent plate (330) when the internal pressure of the case (100) rises above a set size.

[0159] The vent notch (360) according to the present embodiment may have the shape of a groove that is concavely sunken downward from the upper surface of the vent plate (330). The vent notch (360) may be formed such that its cross-sectional area gradually narrows as it moves downward. The vent notch (360) may be formed to form a ring shape along an arc centered on the central axis (C) of the winding hole (201).

[0160] The case (100) according to the present embodiment may further include a clamping part (150) that fixes the position of the cap assembly (300) and prevents the cap assembly (300) from detaching from the case (100).

[0161] The clamping portion (150) according to the present embodiment may extend from the upper portion of the beading portion (140). The end of the clamping portion (150) may be bent toward the central axis of the case (100). The inner surface of the clamping portion (150) may be arranged to wrap around the outer surface of the support portion (341).

[0162] A gasket (G) may be placed between the clamping portion (150) and the cap assembly (300). The gasket (G) electrically insulates the case (100) and the cap assembly (300) from each other and can function as a component that prevents moisture or electrolyte from flowing in or out between the case (100) and the cap assembly (300).

[0163] The gasket (G) according to the present embodiment may include an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc. The gasket (G) may be formed to have a roughly ring shape. The gasket (G) may have a roughly U-shaped cross-section. The outer surface of the gasket (G) may be in close contact with the inner surface of the clamping portion (150) and the beading portion (140). The inner surface of the gasket (G) may wrap around the outer surface of the support portion (341) and be in close contact with the outer surface of the support portion (341).

[0164] The first current collector plate (400) may be placed between the electrode assembly (200) and the cap assembly (300). The first current collector plate (400) may function as a component that electrically connects the electrode assembly (200) and the cap assembly (300). The first current collector plate (400) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0165] FIG. 3 is an enlarged view of a key part schematically showing the configuration of a secondary battery according to the first embodiment of the present invention, FIG. 4 is a plan view schematically showing the center notch configuration of a first current collector plate according to the first embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line V-V of FIG. 4.

[0166] Referring to FIGS. 1 to 5, the first current collector plate (400) according to the present embodiment may have a roughly circular shape. However, the cross-sectional shape of the first current collector plate (400) is not limited to this, and the design can be changed to various shapes such as polygons or ellipses. The first current collector plate (400) may be positioned between one side of the electrode assembly (200), which is positioned to face the opening (130) of the case (100), and the cap down (320). Both sides of the first current collector plate (400) may be positioned to face the electrode assembly (200) and the cap down (320), respectively. The central axis of the first current collector plate (400) may be positioned coaxially with the central axis (C) of the winding hole (201).

[0167] The first current collector plate (400) according to the present embodiment can be connected to the cap assembly (300).

[0168] For example, a first tab (E1) that electrically connects the first current collector plate (400) and the cap down (320) may be disposed between the first current collector plate (400) and the cap down (320). The first tab (E1) may be formed of a conductive material such as copper, nickel, or aluminum. Both ends of the first tab (E1) may be fixed to one surface of the first current collector plate (400) and the cap down (320) by welding or the like.

[0169] However, the first current collector plate (400) is not limited to this, and it is also possible to be in direct contact with the cap down (320) and electrically connected to the cap assembly (300).

[0170] The first current collector plate (400) according to the present embodiment can be connected to the first electrode (210). Accordingly, the first current collector plate (400) according to the present embodiment can function as a positive current collector of the secondary battery (2), and the cap assembly (300) can function as a positive terminal.

[0171] For example, the electrode assembly (200) according to the present embodiment may further include a first non-electrical portion (240) that electrically connects the first current collector plate (400) and the first electrode (210).

[0172] According to the present embodiment, the first blank portion (240) may extend toward the first current collection plate (400) from the end of the first electrode (210) facing the first current collection plate (400). The first blank portion (240) may be formed of the same material as the first electrode (210). The first blank portion (240) may be formed integrally with the first electrode (210). For example, the first blank portion (240) may be formed by cutting off a portion of the first electrode (210) where the first active material layer is not applied during the manufacturing process of the first electrode (210). However, the first blank portion (240) is not limited to this, and it is also possible to manufacture it separately from the first electrode (210) and then combine it with the first electrode (210).

[0173] The notching portion (500) is formed by avoiding the welding line (W) of the first current collector plate (400) and the first non-contained portion (240), and can function as a configuration that breaks when internal pressure is generated.

[0174] The welding lines (W) can be formed in all directions relative to the center of the first current collector plate (400). For example, the welding lines (W) electrically connect the first current collector plate (400) and the first non-contained portion (240) by welding, and as shown in FIG. 4, they can be formed diagonally from the center of the first current collector plate (400).

[0175] The notching portion (500) may include a center notch (510) formed in the center of the first current collection plate (400).

[0176] The guide hole (450) can function as a configuration that penetrates the first current collection plate (400) and provides an injection path for the electrolyte injected into the interior of the case (100).

[0177] The guide hole (450) may include a center hole (460) formed at the center of the first current collection plate (400) and a plurality of side holes (470) formed radially around the center. The center hole (460) of the first current collection plate (400) may be positioned to face the winding hole (201) of the electrode assembly (200).

[0178] The center hole (460) according to the present embodiment may have the shape of a hole penetrating the central part of the first current collection plate (400) in a direction parallel to the central axis of the winding hole (201). The central axis of the center hole (460) may be positioned coaxially with the central axis of the winding hole (201).

[0179] The diameter of the center hole (460) of the first current collector plate (400) may be smaller than the diameter of the winding hole (201). Accordingly, the center hole (460) can prevent the electrolyte injected into the winding hole (201) from coming into direct contact with the separator (230) arranged to surround the winding hole (201). Additionally, the center hole (460) can prevent damage to the separator (230) caused by direct contact between the electrolyte and the separator (230), and prevent direct exposure of the first electrode (210) or the second electrode (220).

[0180] For example, the center notch (510) may be formed in a circular shape. The center notch (510) may include a center hole (460) inside. The center notch (510) may be set larger than the winding hole (201) of the electrode assembly (200) so that vertical heat and pressure can be discharged.

[0181] The diameter of the winding hole (201) can be formed to be 3.3 mm to 3.5 mm, and the diameter of the center notch (510) can be formed to be 4 mm to 8.5 mm. By forming the center notch (510) larger than the diameter of the winding hole (201), a flow path for relieving internal pressure in the event of an internal short circuit can be secured, thereby preventing side rupture of the secondary battery (2).

[0182] The center notch (510) may be formed by an intaglio groove formed by laser cutting or die stamping. The angle of the intaglio formation of the center notch (510) may be 30° to 90°.

[0183] Also, the amount of indentation of the center notch (510) may be 50% to 80% of the thickness (D1) of the first current collector plate (400).

[0184] In this way, by setting the depth relative to the thickness (D1) of the first current collection plate (400) and the angle of the indentation formed by the center notch (510), smooth opening is possible when a short circuit occurs, thereby securing a flow path for relieving internal pressure.

[0185] FIG. 6 is a drawing showing a modified example of the center notch of the first current collection plate according to the first embodiment of the present invention. Referring to FIG. 6, the center notch (510) can be divided into n equal parts. That is, the center notch (510) can be formed by dividing it into multiple parts while maintaining an overall circular shape.

[0186] In this embodiment, the center notch (510) is shown as being divided into three parts at 120° intervals, but it is not limited thereto and may be formed by dividing into various numbers, such as four parts at 90° intervals or six parts at 60° intervals.

[0187] The secondary battery (2) according to the present embodiment may further include a second current collector plate (600).

[0188] The second current collector plate (600) may be placed between the electrode assembly (200) and the case (100). The second current collector plate (600) may function as a component that electrically connects the electrode assembly (200) and the case (100). The second current collector plate (600) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0189] The second current collector plate (600) according to the present embodiment may have a roughly circular shape. However, the cross-sectional shape of the second current collector plate (600) is not limited to this, and the design can be changed to various shapes such as polygons or ellipses. The second current collector plate (600) may be positioned between the bottom portion (120) of the case (100) and the other end portion of the electrode assembly (200). Both sides of the second current collector plate (600) may be positioned to face the bottom portion (120) and the electrode assembly (200), respectively. The central axis of the second current collector plate (600) may be positioned coaxially with the central axis (C) of the winding hole (201).

[0190] The second current collector plate (600) according to the present embodiment can be connected to the case (100).

[0191] For example, a second tap (E2) that electrically connects the second current collector plate (600) and the case (100) may be disposed between the second current collector plate (600) and the bottom part (120). The second tap (E2) may be formed of a conductive material such as copper, nickel, or aluminum. Both ends of the second tap (E2) may be fixed to the second current collector plate (600) and the bottom part (120) by welding or the like.

[0192] However, the second current collector plate (600) is not limited to this, and it is also possible to be in direct contact with the bottom part (120) and electrically connected to the case (100).

[0193] The second current collector plate (600) according to the present embodiment can be connected to the second electrode (220). Accordingly, the second current collector plate (600) according to the present embodiment can function as a negative electrode current collector of the secondary battery (2), and the case (100) can function as a negative electrode terminal.

[0194] For example, the electrode assembly (200) according to the present embodiment may further include a second non-electrical portion (250) that electrically connects the second current collector plate (600) and the second electrode (220).

[0195] According to the present embodiment, the second blank portion (250) may extend toward the second current collector plate (600) from the end of the second electrode (220) facing the second current collector plate (600). The second blank portion (250) may be formed of the same material as the second electrode (220). The second blank portion (250) may be formed integrally with the second electrode (220). For example, the second blank portion (250) may be formed by cutting off a portion of the second electrode (220) where the first active material layer is not applied during the manufacturing process of the second electrode (220). However, the second blank portion (250) is not limited to this, and it is also possible to manufacture it separately from the second electrode (220) and then combine it with the second electrode (220).

[0196] Hereinafter, a secondary battery according to the second embodiment of the present invention will be described.

[0197] The secondary battery (2) according to the present embodiment may 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 notching portion (500).

[0198] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notching portion (500), which is different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0199] 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.

[0200] FIG. 7 is a plan view schematically showing the side notch configuration of the first current collector plate according to the second embodiment of the present invention, and FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 7.

[0201] Referring to FIGS. 7 and FIGS. 8, the notching portion (500) according to the present embodiment may include a plurality of side notches (520) formed on the edge of the first current collection plate (400).

[0202] A guide hole (450) is formed in the first current collection plate (400), and the guide hole (450) penetrates the first current collection plate (400) and can function as a configuration providing an injection path for an electrolyte injected into the interior of the case (100).

[0203] The guide hole (450) may include a center hole (460) formed at the center of the first current collector plate (400) and a plurality of side holes (470) formed radially around the center hole (460). The center hole (460) of the first current collector plate (400) is positioned to face the winding hole (201), and the side holes (470) formed radially around the center hole may be formed as a pair between the welding lines (W) by avoiding the welding line (W).

[0204] The side notch (520) may be formed in a bar shape extending in all directions from the center hole (460) of the first current collection plate (400). The side notch (520) may be formed in a rectangular bar shape, and one end may be connected to the center hole (460) of the first current collection plate (400).

[0205] That is, the side notch (520) can be positioned between the side holes (470) formed in the first current collection plate (400) and can be broken by internal pressure to induce smooth internal pressure and heat dissipation.

[0206] In this embodiment, a side notch (520) may be formed at the 3 o'clock, 9 o'clock, and 12 o'clock directions. This illustrates a form in which a lead tab is provided on the first current collector plate (400). In the case of the first current collector plate (400) that is directly connected without a lead tab, a side notch (520) may be formed at the 6 o'clock direction, although this is not illustrated.

[0207] The side notch (520) may be formed as an intaglio groove formed by laser cutting or die stamping, similar to the center notch (510) of the first embodiment. Also, the angle of intaglio formation of the side notch (520) may be 30° to 90°. Additionally, the amount of intaglio of the side notch (520) may be 50% to 80% relative to the thickness (D1) of the first current collector plate (400).

[0208] In this way, by setting the angle of the side notch (520) engraving and the depth relative to the thickness (D1) of the first current collection plate (400), a smooth opening is possible when a short circuit occurs, thereby securing a flow path for relieving internal pressure.

[0209] Since the side notch (520) is connected to the center hole (460), when internal pressure is generated, the center hole (460) corresponding to the welding line (W) can bend upward and expand the center hole (460).

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

[0211] The secondary battery (2) according to the present embodiment may 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 notching portion (500).

[0212] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notching portion (500), which is 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. 9 is a plan view schematically showing the side notch configuration of the first current collector plate according to the third embodiment of the present invention, and FIG. 10 is a cross-sectional view X-X of FIG. 9.

[0215] Referring to FIG. 9 and FIG. 10, the notching portion (500) according to the present embodiment may include a plurality of side notches (520) formed on the edge of the first current collection plate (400).

[0216] A guide hole (450) is formed in the first current collection plate (400), and the guide hole (450) penetrates the first current collection plate (400) and can function as a configuration providing an injection path for an electrolyte injected into the interior of the case (100).

[0217] The guide hole (450) may include a center hole (460) formed at the center of the first current collector plate (400) and a plurality of side holes (470) formed radially around the center hole (460). The center hole (460) of the first current collector plate (400) is positioned to face the winding hole (201), and the side holes (470) formed radially around the center hole may be formed as a pair between the welding lines (W) by avoiding the welding line (W).

[0218] In this embodiment, the side notch (520) may be formed in multiple numbers around the center hole (460) of the first current collection plate (400). The side notch (520) may include a side hole (470) inside.

[0219] That is, the side notch (520) is formed in a circular shape corresponding to each side hole (470) and can function as a configuration that expands the side hole (470) when internal pressure is generated.

[0220] The side notch (520) is formed in a shape that surrounds each side hole (470) formed in the first current collection plate (400), so that the side hole (470) can be expanded and broken by internal pressure, thereby inducing smooth internal pressure and heat dissipation.

[0221] The side notch (520) may be formed as an intaglio groove formed by laser cutting or die stamping, similar to the center notch (510) of the first embodiment. Also, the angle of intaglio formation of the side notch (520) may be 30° to 90°. Additionally, the amount of intaglio of the center notch (510) may be 50% to 80% relative to the thickness (D1) of the first current collector plate (400).

[0222] In this way, by setting the angle of the side notch (520) engraving and the depth relative to the thickness (D1) of the first current collection plate (400), a smooth opening is possible when a short circuit occurs, thereby securing a flow path for relieving internal pressure.

[0223] FIGS. 11 and FIGS. 12 are drawings showing a modified example of the side notch (520) of the first current collection plate (400) according to the third embodiment of the present invention.

[0224] Referring to FIG. 11, the side notch (520) can be formed in a fan shape that surrounds a plurality of side holes (470). Since the side notch (520) has a fan shape that extends outward from the center hole (460), the outer side with a larger area is broken first, and a wide flow path can be secured to relieve internal pressure and heat through a structure that breaks from the outer side to the inner side, like a can lid.

[0225] Additionally, referring to FIG. 12, the side notch (520) may be formed with a fan-shaped side notch (520) surrounding a plurality of side holes (470) and a circular side notch (520) surrounding each side hole (470).

[0226] In this embodiment, the side notch (520) is illustrated as a fan shape surrounding a plurality of side holes (470) and a circle surrounding an individual side hole (470), but it is not limited thereto and may be formed in various shapes surrounding the side holes (470), which is merely a simple design variation.

[0227] Hereinafter, a secondary battery according to the fourth embodiment of the present invention will be described.

[0228] The secondary battery according to the present embodiment may be configured to differ from the secondary battery according to the first embodiment of the present invention only in the detailed configuration of the notching portion (500).

[0229] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notching portion (500), which is different from the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0230] 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.

[0231] FIG. 13 is a schematic diagram showing the configuration of the notching portion (500) of the first current collection plate (400) according to the fourth embodiment of the present invention, and FIG. 14 is a cross-sectional view taken along XIV-XIV of FIG. 13.

[0232] Referring to FIG. 13 and FIG. 14, the notching portion (500) according to the present embodiment may include a center notch (510) formed at the center of the first current collection plate (400) and a side notch (520) formed at the edge of the first current collection plate (400) connected to the center notch (510).

[0233] A guide hole (450) is formed in the first current collection plate (400), and the guide hole (450) penetrates the first current collection plate (400) and can function as a configuration that provides an injection path for an electrolyte injected into the interior of the case.

[0234] The guide hole (450) may include a center hole (460) formed at the center of the first current collector plate (400) and a plurality of side holes (470) formed radially around the center hole (460). The center hole (460) of the first current collector plate (400) is positioned to face the winding hole (201), and the side holes (470) formed radially around the center hole may be formed as a pair between the welding lines (W) by avoiding the welding line (W).

[0235] For example, the center notch (510) may be formed in a circular shape. The center notch (510) may include a center hole (460) inside. The center notch (510) may be set larger than the winding hole (201) of the electrode assembly (200) so that vertical heat and pressure can be discharged.

[0236] The side notch (520) may be formed in a bar shape extending in all directions from the center hole (460) of the first current collection plate (400). The side notch (520) may be formed in a rectangular bar shape, and one end may be connected to the center notch (510) of the first current collection plate (400).

[0237] That is, the side notch (520) can be positioned between the side holes (470) formed in the first current collection plate (400), and the inner side can be connected to the center notch (510), so that the side notch (520) can be broken together with the center notch (510) by internal pressure, thereby inducing smooth internal pressure and heat dissipation.

[0238] The center notch (510) and the side notch (520) may be formed by intaglio grooves formed by laser cutting or die stamping. Also, the angle of intaglio formation of the center notch (510) and the side notch (520) may be 30° to 90°. Additionally, the amount of intaglio of the center notch (510) and the side notch (520) may be 50% to 80% relative to the thickness (D1) of the first current collector plate (400).

[0239] In this way, by setting the depth relative to the thickness (D1) of the first current collection plate (400) and the angle of the center notch (510) and the side notch (520) forming the indentation, smooth opening is possible when a short circuit occurs, thereby securing a flow path for relieving internal pressure.

[0240] FIG. 15 is a first modified example of the notching portion of the first current collector plate according to the fourth embodiment of the present invention, FIG. 16 is a cross-sectional view taken along XVI-XVI of FIG. 15, and FIG. 17 is a drawing showing a second modified example of the notching portion of the first current collector plate according to the fourth embodiment of the present invention.

[0241] According to the present embodiment, the notching portion (500) is composed of a center notch (510) and a side notch (520), the center notch (510) is formed in a circular shape, and the side notch (520) can be formed in a fan shape extending in the radial direction of the center notch (510).

[0242] The side notch (520) may be configured as a bar-shaped side notch (520) extending in all directions from the center hole (460) of the first current collection plate (400) and a fan-shaped side notch (520).

[0243] It is preferable that the fan-shaped side notch (520) be positioned at the location where the lead tab is provided. The fan-shaped side notch (520) can be formed regardless of the presence or absence of the lead tab.

[0244] At this time, the thickness (D2) of the center notch (510) can be formed to be thicker than the thickness (D3) of the side notch (520), that is, the fan-shaped side notch (520).

[0245] This allows for smoother fracture by forming an early fracture notch, thereby securing a flow path that can smoothly relieve internal pressure and heat. More specifically, the fan-shaped side notch (520) has a fan shape that extends outward from the center hole (460), so the outer side with a larger area receives resistance first. Since it has a thinner wall thickness (D3) than the center notch (510), it can fracture first, and thus, a wide flow path can be secured to relieve internal pressure and heat through a structure that fractures from the outside to the inside, like a can lid.

[0246] The wall thickness (D3) of the side notch (520) may be 15% to 30% of the thickness (D1) of the first current collector plate (400). If it is 15% or less, it may break under small internal pressure, and if it is 30% or more, it may not provide smooth breaking. Also, the ratio of the wall thickness (D3) of the side notch (520) to the wall thickness (D2) of the center notch (510) may be 50% or less. If the wall thickness (D3) of the side notch (520) is 50% or more of the wall thickness (D2) of the center notch (510), the smooth early breaking function may be reduced.

[0247] As a second variation according to the present embodiment, as shown in FIG. 17, the side notch (520) may be configured as a fan-shaped side notch (520) extending in all directions from the center hole (460) of the first current collector plate (400).

[0248] Hereinafter, a secondary battery according to the fifth embodiment of the present invention will be described.

[0249] FIG. 18 is a perspective view schematically showing the configuration of a secondary battery according to the fifth embodiment of the present invention, and FIG. 19 is a cross-sectional view schematically showing the configuration of a secondary battery according to the fifth embodiment of the present invention.

[0250] Referring to FIGS. 18 and 19, the secondary battery (2) according to the present embodiment may include a case (100), an electrode assembly (200), a cap assembly (300), a first current collector plate (400), and a notching portion (500).

[0251] The case (100) and the electrode assembly (200) may be configured in the same way as the case (100) and the electrode assembly (200) of the secondary battery (2) according to the first embodiment of the present invention.

[0252] The cap assembly (300) according to the present embodiment may include a cap plate (370).

[0253] The cap plate (370) forms the exterior of the cap assembly (300) and can seal the case (100).

[0254] The cap plate (370) according to the present embodiment may be formed to have a roughly circular shape. The cap plate (370) may be placed in the opening (130) of the case (100). The central axis of the cap plate (370) may be placed coaxially with the central axis (C) of the winding hole (201). The cap plate (370) may be placed facing one side of the electrode assembly (200) with the beading portion (140) in between. The clamping portion (150) according to the present embodiment may be placed to wrap around the end of the cap plate (370).

[0255] A cap gasket (G1) that electrically insulates the cap plate (370) and the case (100) may be disposed between the cap plate (370) and the clamping part (150).

[0256] The cap gasket (G1) according to the present embodiment may be positioned to completely surround the end of the cap plate (370). The outer surface of the cap gasket (G1) may be pressed and fixed to the inner surface of the beading portion (140) and the crimping portion (150). 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 (370) and the case (100) and can block moisture, foreign substances, etc. from entering between the cap plate (370) and the case (100).

[0257] The clamping portion (150) is positioned to face the other side of the cap plate (370) with the cap gasket (G1) in between, and can press the cap plate (370) toward the beading portion (140) by contacting the cap gasket (G1). Accordingly, the cap plate (370) can be stably fixed on the side of the opening (202) of the case (100).

[0258] The cap assembly (300) according to the present embodiment may be provided with a vent (380) that opens the cap plate (370) as the internal pressure of the case (100) exceeds the set pressure.

[0259] The vent (380) according to the present embodiment may have a thinner thickness compared to other areas of the cap plate (370). For example, the vent (380) may have the shape of a notch formed concavely from one side of the cap plate (370) toward the other side. The vent (380) may be formed to have a ring shape that is spaced apart from the center of the cap plate (370) and forms a concentric circle with the cap plate (370). As another example, the vent (380) may have at least one pattern having a straight or curved shape.

[0260] FIG. 20 is an enlarged view of a key part schematically showing the configuration of a secondary battery according to the fifth embodiment of the present invention, FIG. 21 is a plan view schematically showing the configuration of a notching part (500) of a first current collector plate (400) according to the fifth embodiment of the present invention, and FIG. 22 is a cross-sectional view of ⅡⅩⅡ-ⅡⅩⅡ of FIG. 21.

[0261] Referring to FIGS. 20 to 22, the first current collector plate (400) according to the present embodiment may include a flat portion (420) disposed between the electrode assembly (200) and the cap plate (370), and an extension portion (430) extending from the flat portion (420).

[0262] The flat portion (420) according to the present embodiment may have the shape of a flat plate that is positioned perpendicularly to the central axis (C) of the winding hole (201).

[0263] One side of the flat portion (420) positioned to face the electrode assembly (200) can be connected to the second electrode (220) through the second non-reinforced portion (250). For example, the outer surface of the second bending portion (251) positioned at the end of the second non-reinforced portion (250) can be in contact with one side of the flat portion (420). The second bending portion (251) can be fixed to the flat portion (420) by welding or the like. Accordingly, the first current collector plate (400) according to the present embodiment can function as a negative electrode current collector of the secondary battery (2).

[0264] The extension portion (430) may extend from the edge of the flat portion (420) toward the cap plate (370). The extension portion (430) may come into contact with the inner surface of the beading portion (140). The extension portion (430) may be rounded or bent along the beading portion (140). The extension portion (430) may be connected to the beading portion (140) by welding or the like. Accordingly, the case (100) and the first current collector plate (400) are electrically connected, and the case (100) can function as a negative terminal of the secondary battery (2).

[0265] The extension portion (430) may be formed in multiple numbers. The multiple extension portions (430) may be spaced apart from each other along the edge of the planar portion (420).

[0266] The notching portion (500) is formed by avoiding the welding line (W) of the first current collector plate (400) and the second non-contained portion (250), and can function as a configuration that breaks when internal pressure is generated.

[0267] A welding line (W) can be formed in all directions relative to the center of the first current collector plate (400). For example, the welding line (W) electrically connects the first current collector plate (400) and the second non-contained portion (250) by welding, and can be formed diagonally from the center of the first current collector plate (400) as shown in FIG. 20. The welding line (W) can be formed on an extension portion (430) that extends in all directions. That is, the welding line (W) can be formed at the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions of the first current collector plate (400).

[0268] The notching portion (500) may include a center notch (510) formed in the center of the first current collection plate (400).

[0269] For example, the center notch (510) may be formed in a circular shape. The center notch (510) may be set larger than the winding hole (201) of the electrode assembly (200) so that vertical heat and pressure can be discharged.

[0270] The diameter of the winding hole may be formed to be 3.3 mm to 3.5 mm, and the diameter of the center notch (510) may be formed to be 4 mm to 8.5 mm. By forming the center notch (510) larger than the diameter of the winding hole (201), a flow path for relieving internal pressure in the event of an internal short circuit can be secured, thereby preventing side rupture of the secondary battery (2).

[0271] The center notch (510) may be formed by an engraved groove formed by laser cutting or die stamping. The angle of the engraved formation of the center notch (510) may be 30° to 90°. Also, the amount of the engraved shape of the center notch (510) may be 50% to 80% relative to the thickness (D1) of the first current collector plate (400).

[0272] In this way, by setting the depth relative to the thickness (D1) of the first current collection plate (400) and the angle of the indentation formed by the center notch (510), smooth opening is possible when a short circuit occurs, thereby securing a flow path for relieving internal pressure.

[0273] Hereinafter, a secondary battery according to the 6th embodiment of the present invention will be described.

[0274] The secondary battery (2) according to the present embodiment may 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 notching portion (500).

[0275] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the notching portion (500), which is different from the secondary battery (2) according to the fifth embodiment of the present invention, will be described.

[0276] 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 may be applied as is.

[0277] FIG. 23 is a plan view schematically showing the configuration of the notching portion of the first current collector plate according to the sixth embodiment of the present invention, and FIG. 24 is a cross-sectional view taken along IIⅩⅣ-IIⅩⅣ of FIG. 23.

[0278] Referring to FIG. 23 and FIG. 24, the notching portion (500) according to the present embodiment may include a center notch (510) formed in the center of the first current collection plate (400) and a side notch (520) formed at the edge of the first current collection plate (400) connected to the center notch (510).

[0279] For example, the center notch (510) may be formed in a circular shape. The center notch (510) may be set larger than the winding hole (201) of the electrode assembly (200) so that vertical heat and pressure can be discharged.

[0280] A side notch (520) may be formed on one edge of the first current collector plate (400). The side notch (520) may be formed on one side near the welding line (W). More specifically, as shown in FIG. 22, the side notch (520) is formed at the 7 o'clock direction of the first current collector plate (400) and may be formed in the shape of an arrow pointing toward the center notch (510). At this time, the side notch (520) may be formed in contact with the center notch (510).

[0281] The center notch (510) and the side notch (520) may be formed by intaglio grooves formed by laser cutting or die stamping. Also, the angle of intaglio formation of the center notch (510) and the side notch (520) may be 30° to 90°.

[0282] At this time, the thickness (D2) of the center notch (510) can be formed to be thicker than the thickness (D3) of the side notch (520), that is, the side notch (520) of the arrow.

[0283] This allows for smoother fracture by forming the side notch (520) as an early fracture notch, thereby securing a flow path that can smoothly relieve internal pressure and heat.

[0284] The arrow-shaped side notch (520) has a large surface area adjacent to the center notch (510), so it receives resistance first, and since it has a thinner wall thickness (D3) than the center notch (510), it can break first. As a result, it breaks from the inside to the outside, like a can lid, and since the side notch (520) is formed in contact with the center notch (510), a part of the center notch (510) breaks after the side notch (520) breaks, enabling smooth breaking of the center notch (510). In this way, a wide flow path can be secured to relieve internal pressure and heat through the early breaking of the side notch (520) and the breaking of the center notch (510).

[0285] The wall thickness (D3) of the side notch (520) may be 15% to 30% of the thickness (D1) of the first current collector plate (400). If it is 15% or less, it may break under small internal pressure, and if it is 30% or more, it may not provide smooth breaking. Also, the ratio of the wall thickness (D3) of the side notch (520) to the wall thickness (D2) of the center notch (510) may be 50% or less. If the wall thickness (D3) of the side notch (520) is 50% or more of the wall thickness (D2) of the center notch (510), the smooth early breaking function may be reduced.

[0286] FIG. 25 is a drawing showing a modified example of the notching portion of the first current collection plate according to the 6th embodiment of the present invention.

[0287] Referring to FIG. 25, the notching portion (500) is composed of a center notch (510) and a side notch (520), the center notch (510) is formed in a circular shape, and the side notch (520) can be formed in the shape of a plurality of arrows extending radially from the center notch (510).

[0288] Side notches (520) can be formed on all four sides near the welding line (W). More specifically, the side notches (520) are formed in the 1 o'clock, 5 o'clock, 7 o'clock, and 11 o'clock directions of the first current collector plate (400) and can be formed in the shape of arrows pointing toward the center notch (510). At this time, each side notch (520) can be formed in contact with the center notch (510).

[0289] The arrow-shaped side notch (520) has a large surface area adjacent to the center notch (510), so it receives resistance first, and since it has a thinner wall thickness (D3) than the center notch (510), it can break first. As a result, it breaks from the inside to the outside, like a can lid, and since the side notch (520) is formed in contact with the center notch (510), a part of the center notch (510) breaks after the side notch (520) breaks, enabling smooth breaking of the center notch (510). In this way, a wide flow path can be secured to relieve internal pressure and heat through the early breaking of the side notch (520) and the breaking of the center notch (510).

[0290] In this embodiment, the side notches (520) are shown as a plurality formed on all sides of the center notch (510), but are not limited thereto, and various variations are possible, such as the side notches (520) being formed in two directions, three directions, or mutually symmetrically with respect to the center notch (510).

[0291] Meanwhile, referring to FIG. 19, the second current collector plate (600) according to the present embodiment can be connected to the first electrode (210) through the first blank portion (240). For example, the outer surface of the first bending portion (241) disposed at the end of the first blank portion (240) can be in contact with one surface of the second current collector plate (600). The first bending portion (241) can be fixed to the second current collector plate (600) by welding or the like. Accordingly, in the present embodiment, the second current collector plate (600) can function as a positive current collector of the secondary battery (2).

[0292] The secondary battery (2) according to the present embodiment may further include a terminal (160).

[0293] The terminal (160) is coupled to the case (100) and can be electrically connected to the second current collector plate (600). In this embodiment, the terminal (160) may be a positive terminal. The terminal (160) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0294] The terminal (160) according to the present embodiment can penetrate the bottom portion (120) of the case (100). More specifically, the terminal (160) can be inserted into the interior of a through hole formed in the center of the bottom portion (120). The outer surface of the terminal (160) can be positioned at a predetermined distance from the inner surface of the through hole formed in the center of the bottom portion (120). Both ends of the terminal (160) can be positioned in the interior space and the exterior space of the case (100), respectively.

[0295] Both ends of the terminal (160) positioned in the internal and external spaces of the case (100) are compressed by riveting and can be positioned to face the outer and inner surfaces of the bottom portion (120), respectively. Accordingly, the edge region of the terminal (160) can have a cross-sectional shape approximately U-shaped. Accordingly, the terminal (160) can be stably fixed to the case (100) while penetrating the bottom portion (120).

[0296] A first terminal surface (161) facing the electrode assembly (200) may be formed on one side of the terminal (160) located in the internal space of the case (100). The first terminal surface (161) according to the present embodiment may have a planar shape positioned perpendicular to the central axis (C) of the winding hole (201). The first terminal surface (161) may be in contact with the second current collector plate (600). The second current collector plate (600) may be fixed to the terminal (160) by laser welding or the like while in contact with the first terminal surface (161).

[0297] On the other side of the terminal (160) located in the external space of the case (100), a second terminal surface (162) may be formed, spaced apart from the first terminal surface (161) in a direction parallel to the central axis (C) of the winding hole (201). The second terminal surface (162) according to the present embodiment may have a planar shape facing the external space of the case (100) and arranged parallel to the first terminal surface (161). The terminal (160) may have a structure in which the cross-sectional areas on both sides are different with respect to the bottom portion (120).

[0298] A terminal gasket (G2) that electrically insulates the terminal (160) and the case (100) may be placed between the terminal (160) and the case (100).

[0299] The terminal gasket (G2) according to the present embodiment may be arranged to completely surround the inner circumferential surface of a through hole formed in the bottom portion (120), and the outer surface of the bottom portion (120) facing both ends of the terminal (160). Both sides of the terminal gasket (G2) may be in close contact with the surfaces of the bottom portion (120) and the terminal (160). The terminal gasket (G2) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0300] A case gasket (G3) that electrically insulates the electrode assembly (200) and the bottom portion (120) may be disposed between the electrode assembly (200) and the bottom portion (120). The case gasket (G3) can function as a configuration that electrically insulates the second current collector plate (600) and the bottom portion (120) by blocking direct contact between the case (100) and the second current collector plate (600).

[0301] The case gasket (G3) according to the present embodiment may be positioned between the inner surface of the bottom portion (120) and the second current collector plate (600). The case gasket (G3) may be fixed to the inner surface of the bottom portion (120) through 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.

[0302] Hereinafter, a battery pack including a secondary battery (2) according to various embodiments of the present invention will be described.

[0303] FIG. 26 is a perspective view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0304] Referring to FIG. 26, the battery pack according to the present embodiment includes a housing (1) and a secondary battery (2).

[0305] 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.

[0306] The housing (1) according to the present embodiment may include a housing body (11) and a cover (12).

[0307] 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. 19, but can be designed to have various shapes such as polygons, circles, and ellipses.

[0308] 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.

[0309] 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 sixth embodiments described above.

[0310] 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).

[0311] Multiple secondary batteries (2) can be electrically connected by a bus bar (not shown). Multiple secondary batteries (2) can be connected in series or in parallel by the bus bar. For example, the bus bar 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 can be formed of an electrically conductive material such as copper, aluminum, or nickel.

[0312] 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.

[0313] Therefore, the technical scope of protection of the present invention should be determined by the following patent claims.

Claims

1. Case; An electrode assembly disposed inside the above case and equipped with a non-removable portion; A cap assembly coupled to the above case and positioned facing the electrode assembly; A first current collector plate disposed between the electrode assembly and the cap assembly and coupled to the uncoated portion; and A secondary battery characterized by including a notching portion formed by avoiding the welding line of the first current collection plate and the non-contained portion, and which breaks when internal pressure is generated.

2. In Paragraph 1, A secondary battery characterized in that the above notching portion includes a center notch formed in the center of the first current collection plate.

3. In Paragraph 2, A secondary battery characterized by having a center hole provided inside the center notch.

4. In Paragraph 2, A secondary battery characterized by the above-mentioned center notch being divided into n equal parts.

5. In Paragraph 1, A secondary battery characterized in that the above notching portion includes a plurality of side notches formed at the edge of the first current collection plate.

6. In Paragraph 5, A secondary battery characterized in that the above-mentioned side notch is formed between a plurality of side holes formed in the first current collection plate.

7. In Paragraph 5, A secondary battery characterized in that the above-mentioned side notch surrounds a side hole formed in the above-mentioned first current collection plate.

8. In Paragraph 7, A secondary battery characterized in that the above-mentioned side notch is in a fan shape that surrounds a plurality of the above-mentioned side holes.

9. In Paragraph 1, A secondary battery characterized in that the above notching portion is an intaglio groove formed by laser cutting or die stamping.

10. In Paragraph 1, A secondary battery characterized in that the intaglio formation angle of the above-mentioned notching portion is 30° to 90°.

11. In Paragraph 1, A secondary battery characterized in that the amount of indentation of the above notching portion is 50% to 80% relative to the thickness of the first current collector plate.

12. In Paragraph 1, The above notching portion is a center notch formed at the center of the first current collector plate; and A secondary battery characterized by including a side notch formed at the edge of the first current collection plate and connected to the center notch.

13. In Paragraph 12, The above center notch is formed in a circular shape, and A secondary battery characterized in that the above-mentioned side notch is formed in a bar shape extending in the radial direction of the above-mentioned center notch.

14. In Paragraph 12, The above center notch is formed in a circular shape, and A secondary battery characterized in that the above-mentioned side notch is formed in a fan shape extending in the radial direction of the above-mentioned center notch.

15. In Paragraph 12, A secondary battery characterized in that the above-mentioned side notches are formed in multiple numbers extending in the radial direction of the above-mentioned center notch.

16. In Paragraph 12, A secondary battery characterized in that the thickness of the center notch is thicker than the thickness of the side notch.

17. In Paragraph 16, A secondary battery characterized in that the wall thickness of the side notch is 15% to 30% relative to the thickness of the first current collector plate.

18. In Paragraph 16, A secondary battery characterized in that the wall thickness of the side notch is 50% or less of the wall thickness of the center notch.

19. In Paragraph 1, A secondary battery characterized by including a second current collector plate disposed between the above case and the above electrode assembly.

20. Housing; A plurality of secondary batteries disposed inside the above housing; including The above secondary battery is a case; An electrode assembly disposed inside the above case and equipped with a non-removable portion; A cap assembly coupled to the above case and positioned facing the electrode assembly; A first current collector plate disposed between the electrode assembly and the cap assembly and coupled to the non-removable portion; and A battery pack characterized by including a notching portion formed by avoiding the welding line of the first current collection plate and the non-contained portion, and which breaks when internal pressure is generated.

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