Secondary battery and battery pack including same

Abstract

The present disclosure relates to a secondary battery and a battery pack including same, and the technical problem to be solved is to provide a secondary battery capable of preventing thermal damage to an electrode assembly, and a battery pack including same. To this end, the present disclosure provides a secondary battery comprising: an electrode assembly having a center hole; a case accommodating the electrode assembly and having an open portion and a closed portion; a cap plate sealing the open portion; a first current-collecting plate disposed between the electrode assembly and the closed portion and having a first current-collecting surface facing the electrode assembly and a second current-collecting surface facing the closed portion; a terminal extending through the closed portion and connected to the first current-collecting plate; and a recess concavely formed from the first current-collecting surface toward the second current-collecting surface and disposed to face the center hole.

Description

Secondary battery and battery pack including the same

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

[0002] In general, the recent rapid proliferation of battery-powered electronic devices, such as mobile phones, laptops, and electric vehicles, has led to a rapid increase in demand for high-energy density and high-capacity secondary batteries. Accordingly, active research and development is underway to improve the performance of lithium secondary batteries.

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

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

[0005] The purpose of the present invention is to provide a secondary battery capable of preventing thermal damage to an electrode assembly and a battery pack including the same.

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

[0007] In order to solve the above technical problem, a secondary battery according to the present invention comprises: an electrode assembly having a center hole; a case accommodating the electrode assembly and having an opening portion and a closing portion; a cap plate sealing the opening portion; a first collector plate disposed between the electrode assembly and the closing portion, the first collector plate having a first collector surface facing the electrode assembly and a second collector surface facing the closing portion; a terminal penetrating the closing portion and connected to the first collector plate; and a recess formed concavely from the first collector surface toward the second collector surface and disposed to face the center hole.

[0008] The area of ​​the above recess may be larger than the area of ​​the above center hole.

[0009] The depth of the above recess may be 0.3 mm or more and 2 mm or less.

[0010] The central axis of the above recess and the central axis of the above center hole may be coaxially located.

[0011] The first collector plate includes a filler that protrudes from the second collector surface toward the terminal and comes into contact with the terminal; and the recess can be arranged inside the filler.

[0012] The terminal includes a first terminal surface disposed inside the case and facing the second current collector surface; a second terminal surface spaced apart from the first terminal surface and disposed outside the case; and a terminal recess formed concavely from the first terminal surface toward the second terminal surface; and the filler can be inserted into the inside of the terminal recess.

[0013] The depth of the terminal recess may be less than the height of the filler.

[0014] The area of ​​the terminal recess may be larger than the area of ​​the filler.

[0015] The distance between the outer surface of the above filler and the inner surface of the above terminal recess may be 0.1 mm or more and 10 mm or less.

[0016] The terminal may further include a third terminal surface facing an end of the terminal recess; and a guide recess formed concavely from the third terminal surface toward the second terminal surface and connected to the terminal recess; and the first collector plate may further include a guide filler protruding from the filler and inserted into the guide recess.

[0017] The central axis of the above guide filler and the central axis of the above filler may be positioned coaxially.

[0018] The outer surface of the above guide filler can be in contact with the inner surface of the above guide recess.

[0019] The first collector plate may further include a third collector surface facing the end of the recess, and may further include an extension recess formed concavely inwardly of the guide filler from the third collector surface and connected to the recess.

[0020] The central axis of the above guide filler and the central axis of the above filler may be positioned coaxially.

[0021] The terminal may further include a first terminal coupled to the closure and having the first terminal surface; a second terminal connected to the first terminal and having the second terminal surface; and a terminal filler extending from the first terminal and inserted into the second terminal.

[0022] The central axis of the above guide filler and the central axis of the above terminal filler may be positioned coaxially.

[0023] It may further include one or more fuse holes formed through the first collector plate.

[0024] It may further include a second collector plate disposed between the electrode assembly and the cap plate.

[0025] A battery pack according to the present invention comprises: a housing; a plurality of secondary batteries arranged inside the housing; and a bus bar connecting the plurality of secondary batteries; wherein the secondary battery comprises: an electrode assembly having a center hole; a case accommodating the electrode assembly and having an opening portion and a closing portion; a cap plate sealing the opening portion; a first collector plate disposed between the electrode assembly and the closing portion and having a first collector surface facing the electrode assembly and a second collector surface facing the closing portion; a terminal penetrating the closing portion and connected to the first collector plate; and a recess formed concavely from the first collector surface toward the second collector surface and arranged to face the center hole.

[0026] According to the present invention, thermal damage to the electrode assembly can be reduced by increasing the gap between the connection area of ​​the first collector plate and the terminal, which has a relatively high heat generation temperature during operation of the secondary battery, and the electrode assembly through the recess.

[0027] According to the present invention, by arranging a recess inside a filler protruding from a first collector plate, the depth of the recess can be relatively increased, and the thickness of the first collector plate can be reduced due to the depth of the recess itself, thereby preventing an increase in cell resistance.

[0028] According to the present invention, loss of internal space of the case (200) due to the filler protruding from the first collector plate can be prevented as the filler is inserted into the inside of the terminal recess.

[0029] According to the present invention, the position of the recess can be prevented from being arbitrarily changed by aligning the assembly positions of the terminal and the first collector plate by the guide recess and the guide filler.

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

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

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

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

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

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

[0036] Figure 5 is an enlarged view schematically showing the configuration of a secondary battery according to the first embodiment of the invention.

[0037] Fig. 6 is a schematic drawing showing a state in which the first collector plate and the terminal are separated in Fig. 5.

[0038] Figures 7 and 8 are perspective views schematically showing the configuration of a first collector plate according to a first embodiment of the present invention.

[0039] Figures 9 and 10 are perspective views schematically showing the configuration of a terminal according to the first embodiment of the present invention.

[0040] Figure 11 is a drawing schematically showing the configuration of a secondary battery according to a second embodiment of the present invention.

[0041] Fig. 12 is a drawing schematically showing a state in which the first collector plate and the terminal are separated in Fig. 11.

[0042] Figures 13 and 14 are perspective views schematically showing the configuration of a first collector plate according to a second embodiment of the present invention.

[0043] Fig. 15 is a perspective view schematically showing the configuration of a terminal according to a second embodiment of the present invention.

[0044] Figure 16 is a drawing schematically showing the configuration of a secondary battery according to a third embodiment of the present invention.

[0045] Fig. 17 is a schematic drawing showing a state in which the first collector plate and terminal are separated in Fig. 16.

[0046] Figures 18 and 19 are perspective views schematically showing the configuration of a first collector plate according to a third embodiment of the present invention.

[0047] Fig. 20 is a perspective view schematically showing the configuration of a terminal according to a third embodiment of the present invention.

[0048] Figure 21 is a drawing schematically showing the configuration of a secondary battery according to the fourth embodiment of the present invention.

[0049] Fig. 22 is a drawing schematically showing the configuration of a first collector plate according to a fifth embodiment of the present invention.

[0050] Fig. 23 is a drawing showing a modified example of the fuse hole illustrated in Fig. 22.

[0051] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0052] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0053] Additionally, to facilitate understanding of the invention, the attached drawings are not drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0054] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0055] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0056] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0057] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0058] Additionally, when a component is described as being "on," "connected to," or "coupled to" another component, it should be understood that the components may be directly connected or coupled to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through other components.

[0059] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, the use of "may" when describing embodiments of the present disclosure refers to "one or more embodiments of the present disclosure." Expressions such as "one or more" and "one or more" preceding a list of elements modify the list as a whole and do not modify individual elements in the list.

[0060] When reference is made throughout the specification to “A and / or B,” this means A, B, or A and B, unless otherwise stated, and when reference is made to “C through D,” this means C or more and D or less, unless otherwise stated.

[0061] When phrases such as "at least one of A, B, and C," "at least one of A, B, or C," "at least one selected from the group A, B, and C," or "at least one selected from A, B, and C," are used to specify a list of elements A, B, and C, the phrases can refer to any suitable combination.

[0062] The term "use" may be considered synonymous with the term "utilize." As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than degrees, and are intended to take into account inherent variations in measured or calculated values ​​that would be recognized by those skilled in the art.

[0063] Although terms such as first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could also be termed a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0064] For ease of description, spatially relative terms such as "beneath," "below," "lower," "above," "upper," and the like may be used herein to describe the relationship of one element or feature to another element(s) or feature(s) as depicted in the drawings. It will be understood that spatially relative positions encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device in the drawings is turned over, an element described as "beneath" or "lower" another element would be understood to be "above" or "upper" the other element. Thus, the term "beneath" can encompass both the above and below orientations.

[0065] The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure.

[0066] FIG. 1 is a perspective view schematically showing the configuration of a battery pack according to various embodiments of the present invention, and FIG. 2 is a plan view schematically showing the configuration of a battery pack according to various embodiments of the present invention.

[0067] Referring to FIGS. 1 and 2, a battery pack according to various embodiments may include a housing (1), a secondary battery (2), and a bus bar (3).

[0068] The housing (1) forms the outline of the battery pack and can provide a space in which a secondary battery (2) can be accommodated.

[0069] The housing (1) according to the present embodiment may include a housing body (11) and a cover (12).

[0070] The housing body (11) can be formed to have the shape of a box with an empty interior and one open side. The cross-sectional shape of the housing body (11) is not limited to the square shape shown in Fig. 1, and can be designed to have various shapes such as a polygon, circle, or oval.

[0071] The cover (12) is coupled to the housing body (11) and can close the internal space of the housing body (11). For example, the cover (12) is formed to have a shape roughly like a plate and can be positioned to face the open side of the housing body (11). The cover (12) can be fixed to the housing body (11) by various types of coupling methods such as bolting, welding, and fitting.

[0072] A secondary battery (2) can function as a unit structure that stores and supplies power in a battery pack.

[0073] A plurality of secondary batteries (2) may be provided. The plurality of secondary batteries (2) may be arranged in various patterns, such as a grid shape or a zigzag shape, inside the housing (1). The plurality of secondary batteries (2) may be arranged in parallel with each other. The number of secondary batteries (2) may be designed in various ways depending on the size, shape, etc. of the housing (1). The detailed configuration of the secondary battery will be described later.

[0074] The bus bar (3) can electrically connect a plurality of secondary batteries (2). The plurality of secondary batteries (2) can be connected in series or parallel by the bus bar (3). For example, the bus bar (3) can connect secondary batteries (2) arranged in the same row inside the housing (1) in parallel with each other, and connect secondary batteries (2) arranged in two adjacent rows in series with each other. The bus bar (3) can be formed of an electrically conductive material such as copper, aluminum, or nickel.

[0075] Referring to FIG. 2, the bus bar (3) according to the present embodiment may include a main bus bar (31), a first branch bus bar (32), and a second branch bus bar (33).

[0076] The main bus bar (31) can be arranged between rows of neighboring secondary batteries (2). The main bus bar (31) can be provided in multiple numbers. The main bus bar (31) can extend in a straight line between rows of secondary batteries (2), or alternatively, it can be regularly bent in a zigzag shape. The multiple main bus bars (31) can be individually arranged between different rows of neighboring secondary batteries (2). The multiple main bus bars (31) can be electrically interconnected.

[0077] The first branch bus bar (32) can extend from the main bus bar (31) toward the terminal (600) of the secondary battery (2) described later. The first branch bus bar (32) can be mechanically and electrically connected to the terminal (600) by laser welding, ultrasonic welding, or the like. The first branch bus bar (32) can be provided in multiple pieces. The multiple first branch bus bars (32) can be individually connected to the terminals (600) of different secondary batteries (2).

[0078] The second branch bus bar (33) can extend from the main bus bar (31) toward the case (200) of the secondary battery (2) described later. The second branch bus bar (33) can be mechanically and electrically connected to the case (200) by laser welding, ultrasonic welding, or the like. The second branch bus bar (33) can be provided in multiple pieces. The multiple second branch bus bars (33) can be individually connected to the cases (200) of different secondary batteries (2).

[0079] Below, a secondary battery (2) according to various embodiments of the present invention will be described.

[0080] FIG. 3 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, FIG. 4 is a cross-sectional view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, FIG. 5 is an enlarged view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention, and FIG. 6 is a drawing schematically showing a state in which the first collector plate and the terminal are separated in FIG. 5.

[0081] Referring to FIGS. 3 to 6, a secondary battery (2) according to the present embodiment includes an electrode assembly (100), a case (200), a cap plate (300), a first collector plate (400), a terminal (600), and a recess (700).

[0082] Hereinafter, the secondary battery is described as a cylindrical lithium ion secondary battery as an example. However, the present invention is not limited thereto, and the secondary battery may be a lithium polymer battery or a square battery.

[0083] The electrode assembly (100) can function as a unit structure that performs charging and discharging operations of power in a secondary battery.

[0084] The electrode assembly (100) may include a first electrode plate (110), a second electrode plate (120), and a separator (130) disposed between the first electrode plate (110) and the second electrode plate (120).

[0085] The electrode assembly (100) may have a wound shape centered on the winding axis (C).

[0086] More specifically, the electrode assembly (100) may have a shape in which the first electrode plate (110), the separator (130), and the second electrode plate (120) are laminated and wound around the winding axis (C) in a clockwise or counterclockwise direction. Accordingly, the electrode assembly (100) may have an approximate jelly roll shape. The cross-sectional shape of the electrode assembly (100) may be designed to have various shapes, such as an oval or a polygon, in addition to a circle. Here, the winding axis (C) may mean a straight line penetrating the center of the electrode assembly (100).

[0087] A center hole (A) may be formed in the central portion of the electrode assembly (100). The center hole (A) may extend in a first direction within the electrode assembly (100) and penetrate both upper and lower sides of the electrode assembly (100). The first direction described below may refer to a direction from the lower side to the upper side with reference to FIG. 4 among directions parallel to the winding axis (C) of the electrode assembly (100). The central axis of the center hole (A) may be positioned coaxially with the winding axis (C).

[0088] The first electrode plate (110) can function as the positive electrode of the electrode assembly (100). The first electrode plate (110) can be formed to have the form of a foil containing a metal material such as aluminum or an aluminum alloy. The type, size, and shape of the first electrode plate (110) are not particularly limited as long as it is conductive and does not cause chemical changes in the secondary battery.

[0089] A first active material layer may be applied to at least a portion of the first electrode plate (110). The first active material layer may be applied to both surfaces of the first electrode plate (110), or alternatively, it may be applied to only one surface of the first electrode plate (110).

[0090] As the first electrode plate (110) functions as an anode, the first active material layer may include a cathode active material.

[0091] The cathode active material may be a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound). More specifically, one or more of a composite oxide of lithium and a metal selected from the group consisting of cobalt, manganese, nickel, iron, and combinations thereof may be used.

[0092] For example, the cathode active material may include at least one of lithium-iron-phosphorus oxide (LiFePO4, LFP), lithium-manganese-iron-phosphorus oxide (LiMnFePO4, LMFP), and lithium-nickel-cobalt-manganese oxide (LiNixCoyMnzO2, NCM). Here, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1을 만족할 수 있다. 양극 활물질은 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM) 중 어느 하나만을 포함할 수 있고, 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM)중 어느 두개 또는 이들을 모두 포함하는 것도 가능하다.

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

[0094] The positive electrode conductive material is used to impart conductivity to the first active material layer, and any material that does not cause chemical changes and is electronically conductive can be used. Examples of positive electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0095] The first active material layer may further include a positive electrode binder.

[0096] The positive electrode binder serves to attach the particles constituting the positive electrode active material well to each other and also to attach the positive electrode active material well to the first electrode plate (110).

[0097] Examples of positive binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0098] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0099] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0100] When using an aqueous binder as a positive electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0101] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0102] The first electrode plate (110) may include a first non-coated portion (111) on which the first active material layer is not applied. The first non-coated portion (111) may protrude a predetermined distance in the first direction from one end of the electrode assembly (100).

[0103] The second electrode plate (120) can function as a cathode of the electrode assembly (100). The second electrode plate (120) can be formed to have the shape of a foil containing a metal material such as copper, copper alloy, nickel, or nickel alloy. The second electrode plate (120) can be arranged to face the first electrode plate (110) at a predetermined distance apart from it.

[0104] The second electrode plate (120) is not particularly limited in type, size, shape, etc., as long as it has conductivity and does not cause chemical changes in the secondary battery.

[0105] A second active material layer may be applied to at least a portion of the second electrode plate (120). The second active material layer may be applied to both surfaces of the second electrode plate (120), or alternatively, it may be applied to only one surface of the second electrode plate (120).

[0106] As the second electrode plate (120) functions as a cathode, the second active material layer may include a cathode active material.

[0107] The negative active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0108] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite, such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0109] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0110] As a material capable of doping and dedoping lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-Q alloy (wherein Q is selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (excluding Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof), or a combination thereof. The Sn-based negative electrode active material can be Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0111] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the composite may include secondary particles (cores) in which silicon primary particles are assembled, and an amorphous carbon coating layer (shell) positioned on the surface of the secondary particles. The amorphous carbon may also be positioned between the silicon primary particles, such that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

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

[0113] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in a mixture with a carbon-based negative electrode active material.

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

[0115] The negative electrode conductive material is used to provide conductivity to the second active material layer, and any material that does not cause chemical changes and is electronically conductive can be used. Examples of negative electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0116] The negative electrode binder serves to attach the particles constituting the negative electrode active material well to each other and also to attach the negative electrode active material well to the second electrode plate (120).

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

[0118] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0119] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0120] When using an aqueous binder as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0121] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0122] The second electrode plate (120) may include a second non-coated portion (121) on which a second active material layer is not applied. The second non-coated portion (121) may protrude a predetermined distance in a direction opposite to the first direction from the other end of the electrode assembly (100) located on the opposite side of the first non-coated portion (111).

[0123] A separator (130) may be placed between the first electrode plate (110) and the second electrode plate (120). The separator (130) may perform a function of preventing a short circuit between the first electrode plate (110) and the second electrode plate (120) while allowing the movement of lithium ions between the first electrode plate (110) and the second electrode plate (120).

[0124] As such a separation membrane (130), a multilayer membrane of two or more layers of polyethylene, polypropylene, polyvinylidene fluoride, or these may be used, and a mixed multilayer membrane such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0125] The separation membrane (130) may include a porous substrate and a coating layer including an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0126] The above porous substrate may be a polymer film formed of any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyether ketone, polyarylether ketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more thereof.

[0127] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0128] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include inorganic particles selected from, but not limited to, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0129] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0130] The separator (130) may be provided as a pair. The pair of separators (130) may be arranged to face each other on both sides of the first electrode plate (110) or the second electrode plate (120). The pair of separators (130) may be wound around the winding axis (C) together with the first electrode plate (110) and the second electrode plate (120).

[0131] The case (200) forms a rough outline of the secondary battery (2) and can accommodate the electrode assembly (100). The case (200) can be provided to be electrically conductive. For example, the case (200) can include at least one material selected from the group consisting of steel, stainless steel, aluminum, and an aluminum alloy.

[0132] The case (200) may include a can (201), an opening (202), and a closing portion (203).

[0133] The can (201) may be formed to have a cylindrical shape with a cross-section that is approximately circular. The diameter of the can (201) may be larger than the diameter of the electrode assembly (100). The length of the can (201) parallel to the winding axis (C) of the electrode assembly (100) may be larger than the length of the electrode assembly (100).

[0134] The electrode assembly (100) can be accommodated inside the can (201). The central axis of the can (201) can be arranged to be coaxial with the winding axis (C) of the electrode assembly (100).

[0135] The opening portion (202) and the closing portion (203) may be respectively positioned at both ends of the can (201). The opening portion (202) and the closing portion (203) may be positioned spaced apart from each other along the first direction.

[0136] The opening (202) according to the present embodiment may be formed to have the shape of a hole penetrating one end of the can (201). Both sides of the opening (202) may be connected to the internal space of the can (201) and the external space of the can (201), respectively. During the manufacturing process of the secondary battery (2), the electrode assembly (100) may be inserted into the interior of the can (201) through the opening (202) together with the electrolyte.

[0137] The closure part (203) according to the present embodiment may be formed to have a circular shape that is placed at the other end of the can (201) spaced apart from the opening part (202) in the first direction. The outer circumference of the closure part (203) may be formed integrally with the inner circumference of the can (201) to seal the other end of the can (201). For example, the can (201) and the closure part (203) may be formed by a deep drawing process. Alternatively, the closure part (203) may be manufactured separately from the can (201) and the outer circumference may be joined to the inner circumference of the can (201). A through hole may be formed in the center of the closure part (203) to provide a path for inserting a terminal (600) described below.

[0138] The first non-conductive portion (111) of the electrode assembly (100) may be positioned so as to face the closed portion (203) inside the can (201). The second non-conductive portion (121) of the electrode assembly (100) may be positioned so as to face the open portion (202) inside the can (201).

[0139] A case gasket (G3) that electrically insulates the electrode assembly (100) and the closure (203) may be placed between the electrode assembly (100) and the closure (203). The case gasket (G3) may function as a component that electrically insulates the electrode assembly (100) and the closure (203) by blocking direct contact between the case (200) and the first electrode plate (110) or the case (200) and the first current collector plate (400).

[0140] The case gasket (G3) according to the present embodiment may be placed between one surface of the electrode assembly (100) from which the first non-conductive portion (111) protrudes and the inner surface of the closing portion (203) arranged to face the inner space of the can (201). The case gasket (G3) may be fixed to the inner surface of the closing portion (203) using an adhesive or the like. The case gasket (G3) may be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like.

[0141] The case (200) according to the present embodiment may further include a beading portion (204).

[0142] The beading portion (204) may refer to a portion of the can (201) that protrudes from the inner circumference of the can (201) toward the central axis of the can (201) among the entire area of ​​the can (201). The beading portion (204) may be formed by pressing the outer circumference of the can (201) from the side adjacent to the opening portion (202). The beading portion (204) may be in contact with the other end of the electrode assembly (100) from which the second non-stick portion (121) protrudes. Accordingly, the beading portion (204) may suppress the electrode assembly (100) from moving or being separated from the inside of the can (201).

[0143] The cap plate (300) can be configured to seal the opening (202) of the case (200).

[0144] The cap plate (300) according to the present embodiment may be formed to have an approximately circular shape. The cap plate (300) may be placed inside the can (201). The cap plate (300) may be placed inside the can (201) to face the other end of the electrode assembly (100) with the beading portion (204) therebetween. One surface of the cap plate (300) may be seated on the beading portion (204). The other surface of the cap plate (300) may be placed to face the external space of the can (201).

[0145] A crimping portion (205) for fixing a cap plate (300) may be formed at one end of the can (201) where the opening portion (202) is formed. The crimping portion (205) according to the present embodiment may be bent from one end of the can (201) and may be positioned to face the other surface of the cap plate (300) which is positioned to face the external space of the can (201).

[0146] A cap gasket (G1) that electrically insulates the cap plate (300) and the case (200) may be placed between the cap plate (300) and the crimping portion (205).

[0147] The cap gasket (G1) according to the present embodiment may be arranged to entirely surround the end of the cap plate (300). The outer surface of the cap gasket (G1) may be press-fixed to the inner surface of the beading portion (204) and the crimping portion (205). The cap gasket (G1) may be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like. Accordingly, the cap gasket (G1) may electrically insulate the cap plate (300) and the case (200), and prevent moisture, foreign substances, etc. from entering between the cap plate (300) and the case (200).

[0148] The crimping portion (205) is positioned to face the other surface of the cap plate (300) with the cap gasket (G1) interposed therebetween, and can press the cap plate (300) toward the beading portion (204) by coming into contact with the cap gasket (G1). Accordingly, the cap plate (300) can be stably fixed on the opening portion (202) side of the case (200).

[0149] The cap plate (300) may be formed of a metal material to secure mechanical rigidity, or alternatively, may be formed of a synthetic resin material that does not have electrical conductivity.

[0150] The cap plate (300) may be provided with a vent (301) that opens when the internal pressure of the can (201) exceeds a set pressure.

[0151] The vent (301) according to the present embodiment may be thinner than other areas of the cap plate (300). For example, the vent (301) may have a notch shape that is concavely formed from one side of the cap plate (300) toward the other side. The vent (301) may be spaced apart from the center of the cap plate (300) and may be formed to have a ring shape that is concentric with the cap plate (300). As another example, the vent (301) may have at least one pattern having a straight or curved shape.

[0152] The first collector plate (400) is placed between the electrode assembly (100) and the closure (203) and can be connected to the electrode assembly (100). The first collector plate (400) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0153] Figures 7 and 8 are perspective views schematically showing the configuration of a first collector plate according to a first embodiment of the present invention.

[0154] Referring to FIGS. 1 to 8, the first collector plate (400) according to the present embodiment may be formed to have a shape roughly similar to a circular plate. The area of ​​the first collector plate (400) may be equal to or smaller than the area of ​​one side of the electrode assembly (100). The central axis of the first collector plate (400) may be positioned coaxially with the winding axis (C) of the electrode assembly (100).

[0155] The first collector plate (400) may include a first collector surface (401) and a second collector surface (402) positioned opposite to each other along the first direction.

[0156] The first current collector surface (401) may be a surface facing the electrode assembly (100) among both sides of the first current collector plate (400) that is perpendicular to the first direction. The first current collector surface (401) may be in contact with an end of the first non-stick portion (111) protruding from the electrode assembly (100) in the first direction and may be electrically connected to the first non-stick portion (111). For example, the end of the first non-stick portion (111) may be bent in a direction parallel to the first current collector plate (400) and may be connected to the first current collector surface (401) by welding or the like. The bending direction of the first non-stick portion (111) may be a direction toward the winding axis (C) of the electrode assembly (100). Accordingly, in the present embodiment, the first current collector plate (400) may function as a positive electrode current collector plate.

[0157] The second collector surface (402) may be a surface facing the closed portion (230) among the two sides of the first collector plate (400) that are perpendicular to the first direction. The second collector surface (402) may be positioned at a predetermined distance from the inner surface of the closed portion (230). The second collector surface (402) may be electrically connected to a terminal (600) described below.

[0158] The secondary battery (2) according to the present embodiment may further include a second collector plate (600).

[0159] The second collector plate (500) is placed between the electrode assembly (100) and the cap plate (300) and can be connected to the electrode assembly (100). The second collector plate (500) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0160] The second collector plate (500) according to the present embodiment may include a flat portion (510) facing the other surface of the electrode assembly (100) from which the second non-conductive portion (121) protrudes, and an extension portion (520) extending from the flat portion (510).

[0161] One side of the flat portion (510) facing the other side of the electrode assembly (100) can be connected to the second non-coated portion (121). Accordingly, the second collector plate (500) in the present embodiment can function as a negative collector plate. An end of the second non-coated portion (121) can be bent in a direction parallel to the flat portion (510) and connected to one side of the flat portion (510) by welding or the like. The bending direction of the second non-coated portion (121) can be a direction toward the winding axis (C) of the electrode assembly (100).

[0162] The extension portion (520) may extend from the edge of the flat portion (510) toward the cap plate (300). The extension portion (520) may contact the inner surface of the bead portion (204). The extension portion (520) may be rounded or bent along the bead portion (204). The extension portion (520) may be connected to the bead portion (204) by welding or the like. Accordingly, the case (200) and the second electrode plate (120) are electrically connected, and the closing portion (203) may function as a negative terminal.

[0163] The second branch bus bar (33) is mounted on the outer surface of the closure section (203) of the case (200) and can be mechanically and electrically connected to the closure section (203) by welding or the like. As the case (200) is electrically connected to the second non-conductive section (121) by the second collector plate (500), the second branch bus bar (33) can function as a negative bus bar.

[0164] The extension portion (520) may be formed in multiple pieces. The multiple extension portions (520) may be arranged spaced apart from each other along the edge of the flat portion (510).

[0165] However, the secondary battery (2) according to the present embodiment is not limited to this, and it is also possible for the second non-conductive portion (121) of the electrode assembly (100) to be directly connected to the cap plate (300).

[0166] The terminal (600) is coupled to the case (200) and can be connected to the first collector plate (400). The terminal (600) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0167] Figures 9 and 10 are perspective views schematically showing the configuration of a terminal according to the first embodiment of the present invention.

[0168] Referring to FIGS. 1 to 10, a terminal (600) according to the present embodiment may include a first terminal (610) and a second terminal (620).

[0169] The first terminal (610) may refer to a portion of the terminal (600) that is coupled to the case (200) among the entire area of ​​the terminal (600).

[0170] The first terminal (610) according to the present embodiment can penetrate the closure portion (203) of the case (200). More specifically, the first terminal (610) can be inserted into the inside of the through hole formed in the central portion of the closure portion (203). The outer circumferential surface of the first terminal (610) can be arranged to be spaced apart from the inner circumferential surface of the through hole formed in the central portion of the closure portion (203) by a predetermined distance. The two ends of the first terminal (610) can be arranged in the inner space and the outer space of the can (201), respectively.

[0171] The two ends of the first terminal (610) arranged in the inner and outer spaces of the can (201) can be compressed and deformed by riveting and arranged to face the outer and inner surfaces of the closure (203), respectively. Accordingly, the edge area of ​​the first terminal (610) can have a cross-sectional shape that is approximately U-shaped. Accordingly, the first terminal (610) can be stably fixed to the case (200) while penetrating the closure (203).

[0172] A first terminal surface (601) may be formed on one side of a first terminal (610) arranged in the internal space of a can (201). The first terminal surface (601) may be arranged perpendicular to the first direction. The first terminal surface (601) may be arranged to face the second current collector surface (402) of the first current collector plate (400) in parallel. The first terminal surface (601) may be in contact with the second current collector surface (402) and may be mechanically and electrically connected to the second current collector surface (402) by welding or the like. Accordingly, the terminal (600) may function as a positive terminal of the secondary battery (2).

[0173] Since the first terminal (610) and the closing part (230) have different polarities, a terminal gasket (G2) that electrically insulates the terminal (600) and the case (200) may be placed between the first terminal (610) and the closing part (230).

[0174] The terminal gasket (G2) according to the present embodiment may be arranged to entirely surround the inner surface of the through hole formed in the closure portion (203) and the outer surface and outer side of the closure portion (203) facing both ends of the first terminal (610). Both sides of the terminal gasket (G2) may be in close contact with the surfaces of the closure portion (203) and the first terminal (610). The terminal gasket (G2) may be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like.

[0175] The second terminal (620) is placed on the outside of the case (200) and can be connected to the first terminal (610).

[0176] The second terminal (620) according to the present embodiment may be arranged so that one side faces the other side of the first terminal (610) arranged in the external space of the can (201). The second terminal (620) may be mechanically and electrically connected to the other side of the first terminal (610) by welding or the like. The material of the second terminal (620) and the material of the first terminal (610) may be the same, or alternatively, they may be formed differently.

[0177] A second terminal surface (602) may be formed on the other side of the second terminal (620) that is not arranged to face the other side of the first terminal (610). The second terminal surface (602) may be arranged to be spaced apart from the first terminal surface (601) by a predetermined distance in the first direction. The second terminal surface (602) may have a plane shape that faces the external space of the can (201) and is arranged parallel to the first terminal surface (601). The second terminal surface (602) may be arranged perpendicular to the first direction.

[0178] The first branch bus bar (32) is mounted on the second terminal surface (602) of the terminal (600) and can be mechanically and electrically connected to the second terminal surface (602) by welding or the like. Accordingly, the first branch bus bar (32) can function as a positive bus bar.

[0179] In the above, the terminal (600) is described as being divided into a first terminal (610) and a second terminal (620) as an example, but the terminal (600) is not limited to this, and it is also possible to provide a single configuration in which the first terminal (610) and the second terminal (620) are formed integrally.

[0180] The recess (700) is provided in the first collector plate (400) and can prevent damage to the electrode assembly (100) due to heat generation of the first collector plate (400). More specifically, when the secondary battery (2) is operated, current is transmitted to the first collector plate (400) or the terminal (600) through the joining portion of the first collector plate (400) and the terminal (600), that is, the welding area between the second collector surface (402) and the first terminal surface (601). Accordingly, heat generation of the first collector plate (400) is concentrated in the welding area between the second collector surface (402) and the first terminal surface (601), and the temperature of the central portion of the first collector plate (400) increases relatively more than the temperature of the remaining portion of the first collector plate (400). The recess (700) is configured to increase the gap between the first collector plate (400) and the electrode assembly (100) in the central region of the first collector plate (400) where heat is concentrated, thereby preventing damage to the electrode assembly (100) due to heat generation from the first collector plate (400).

[0181] The recess (700) according to the present embodiment may have a groove shape that is concavely formed from the first collector surface (401) toward the second collector surface (402). The central axis of the recess (700) may be positioned coaxially with the central axis of the center hole (A), i.e., the winding axis (C) of the electrode assembly (100). The cross-sectional shape of the recess (700) may be designed to have various shapes such as a polygon or an oval in addition to the circular shape illustrated in FIG. 7. The depth (h0) of the recess (700) parallel to the first direction may be smaller than the thickness of the first collector plate (400) parallel to the first direction. Accordingly, the first collector plate (400) may be configured to further include a third collector surface (403) facing the end of the recess (700). The third front surface (403) may be arranged parallel to the first front surface (401) and the second front surface (402). For example, the depth (h0) of the recess (700) may be 0.3 mm or more and 2 mm or less.

[0182] The area of ​​the recess (700) may be larger than the area of ​​the center hole (A). For example, the diameter (D2) of the recess (700) may be larger than the diameter (D1) of the center hole (A). Accordingly, when the welding area between the second collector surface (402) and the first terminal surface (601) is larger than the area of ​​the center hole (A), the recess (700) can prevent thermal damage to the first electrode plate (110) and the second electrode plate (120) located outside the center hole (A). Various design changes are possible within a range where the diameter (D2) of the recess (700) of the first collector plate (400) is larger than the diameter (D1) of the center hole (A), and the center hole (A) can maintain contact with the first non-conductive portion (111) located closest to it.

[0183] Below, a secondary battery (2) according to a second embodiment of the present invention will be described.

[0184] 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 first collector plate (400) and the terminal (600).

[0185] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the first collector plate (400) and terminal (600), which are different from those of the secondary battery (2) according to the first embodiment of the present invention, will be described.

[0186] The description of the secondary battery (2) according to the first embodiment of the present invention can be applied as is to the remaining configuration of the secondary battery (2) according to the present embodiment.

[0187] FIG. 11 is a drawing schematically showing the configuration of a secondary battery according to a second embodiment of the present invention, FIG. 12 is a drawing schematically showing a state in which the first collector plate and the terminal are separated in FIG. 11, FIG. 13 and FIG. 14 are perspective views schematically showing the configuration of the first collector plate according to the second embodiment of the present invention, and FIG. 15 is a perspective view schematically showing the configuration of the terminal according to the second embodiment of the present invention.

[0188] Referring to FIGS. 11 to 15, the first collector plate (400) according to the present embodiment may further include a filler (410).

[0189] The filler (410) may protrude from the second collector surface (402) of the first collector plate (400) toward the terminal (600). The longitudinal direction of the filler (410) may be arranged parallel to the first direction. The central axis of the filler (410) may be positioned coaxially with the winding axis (C) of the electrode assembly (100), i.e., the central axis of the center hole (A).

[0190] The recess (700) can be placed inside the filler (410).

[0191] The recess (700) according to the present embodiment may have a groove shape that is concavely formed from the first collector surface (401) of the first collector plate (400) toward the inside of the filler (410). The third collector surface (403) may be the inner surface of the filler (410) located on the opposite side of the end surface of the filler (410) facing the terminal (600).

[0192] Accordingly, the secondary battery (2) according to the present embodiment can more effectively prevent damage to the electrode assembly (100) caused by heat generated in the central region of the first collector plate (400) by relatively increasing the depth (h0) of the recess (700) and the gap between the third collector surface (403) and the electrode assembly (100) compared to the secondary battery (2) according to the first embodiment. In addition, the secondary battery (2) according to the present embodiment can prevent damage to the electrode assembly (100) caused by heat generated in the central region of the first collector plate (400) by arranging the recess (700) inside the filler (410) protruding from the first collector plate (400), thereby preventing the thickness of the first collector plate (400) from being reduced due to the depth of the recess (700) itself, thereby preventing an increase in cell resistance.

[0193] The terminal (600) according to the present embodiment may further include a terminal recess (611).

[0194] The terminal recess (611) can provide a space in which a filler (410) can be accommodated on the inside of the terminal (600).

[0195] The terminal recess (611) according to the present embodiment may have a groove shape that is concavely formed from the first terminal surface (601) toward the second terminal surface (602). The central axis of the terminal recess (611) may be positioned coaxially with the winding axis (C) of the electrode assembly (100), that is, the central axis of the center hole (A). The cross-sectional shape of the terminal recess (611) may be designed to have various shapes such as a polygon or an oval in addition to the circular shape illustrated in FIG. 15. The terminal (600) according to the present embodiment may be configured to further include a third terminal surface (603) facing the end of the filler (410).

[0196] The filler (410) may be inserted into the terminal recess (611). For this purpose, the area of ​​the terminal recess (611) may be larger than the area of ​​the filler (410). For example, the diameter (D4) of the terminal recess (611) may be larger than the diameter (D3) of the filler (410). The outer circumference of the filler (410) may be spaced apart from the inner circumference of the terminal recess (611) by a predetermined distance. The distance between the outer circumference of the filler (410) and the inner circumference of the terminal recess (611) may be 0.1 mm or more and 10 mm or less. Accordingly, the terminal recess (611) can prevent loss of the internal space of the case (200) due to the filler (410) protruding from the first collector plate (400).

[0197] The end surface of the filler (410) may be in contact with the third terminal surface (603). The depth (h2) of the terminal recess (611) parallel to the first direction may be smaller than the height (h1) of the filler (410). Accordingly, the terminal recess (611) may induce the high-heat region of the first collector plate (400) to be formed at a position facing the recess (700) by allowing the contact between the end surface of the filler (410) and the third terminal surface (613) to occur before the contact between the second collector surface (402) and the first terminal surface (601).

[0198] Below, a secondary battery (2) according to a third embodiment of the present invention will be described.

[0199] The secondary battery (2) according to the present embodiment may be configured to differ from the secondary battery (2) according to the second embodiment of the present invention only in the detailed configuration of the first collector plate (400) and the terminal (600).

[0200] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the first collector plate (400) and terminal (600), which are different from those of the secondary battery (2) according to the second embodiment of the present invention, will be described.

[0201] The description of the secondary battery (2) according to the second embodiment of the present invention can be applied as is to the remaining configuration of the secondary battery (2) according to the present embodiment.

[0202] FIG. 16 is a drawing schematically showing the configuration of a secondary battery according to a third embodiment of the present invention, FIG. 17 is a drawing schematically showing a state in which the first collector plate and the terminal are separated in FIG. 16, FIG. 18 and FIG. 19 are perspective views schematically showing the configuration of the first collector plate according to a third embodiment of the present invention, and FIG. 20 is a perspective view schematically showing the configuration of a terminal according to a third embodiment of the present invention.

[0203] Referring to FIGS. 16 to 20, the first collector plate (400) according to the present embodiment may further include a guide filler (420).

[0204] The guide filler (420) may protrude from the end surface of the filler (410) that is in contact with the third terminal surface (603) toward the terminal (600). The longitudinal direction of the guide filler (420) may be arranged parallel to the first direction. The central axis of the guide filler (420) may be positioned coaxially with the central axis of the filler (410).

[0205] The terminal (600) according to the present embodiment may further include a guide recess (612).

[0206] The guide recess (612) can provide a space in which a guide filler (420) can be accommodated on the inside of the terminal (600). Accordingly, the guide recess (612) and the guide filler (420) can function as a configuration that aligns the relative position of the first collector plate (400) with respect to the terminal (600) when assembling the first collector plate (400) and the terminal (600).

[0207] The guide recess (612) according to the present embodiment may have a groove shape that is concavely formed from the third terminal surface (603) toward the second terminal surface (602). The central axis of the guide recess (612) may be positioned coaxially with the winding axis (C) of the electrode assembly (100), i.e., the central axis of the center hole (A). The cross-sectional shape of the guide recess (612) may be designed to have various shapes such as a polygon or an oval in addition to the circular shape illustrated in FIG. 20. In the present embodiment, the terminal (600) may be configured to further include a fourth terminal surface (604) facing the end of the guide filler (420).

[0208] The guide filler (420) can be inserted into the inside of the guide recess (612). The outer surface of the guide filler (420) can be in contact with the inner surface of the terminal recess (611). Accordingly, the guide filler (420) can increase the current-carrying area of ​​the first collector plate (400) and the terminal (600), thereby reducing cell resistance.

[0209] The depth (h4) of the guide recess (612) parallel to the first direction may be equal to or greater than the height (h3) of the guide filler (420). Accordingly, the guide recess (612) can prevent the resistance of the first collector plate (400) from increasing by ensuring that the contact between the end surface of the filler (410) and the third terminal surface (613) occurs before the contact between the guide filler (420) and the fourth terminal surface (604).

[0210] The secondary battery (2) according to the present embodiment may further include an extension recess (800).

[0211] The extension recess (800) can function as a configuration that extends the distance between the electrode assembly (100) and the first collector plate (400) in the welding area of ​​the first collector plate (400) and the terminal (600). Accordingly, the extension recess (800) can more effectively prevent damage to the electrode assembly (100) due to heat generation of the first collector plate (400).

[0212] The extension recess (800) according to the present embodiment may have a groove shape that is concavely formed from the third collector surface (403) toward the inside of the guide filler (420). The extension recess (800) may be connected to the recess (700). In the present embodiment, the first collector plate (400) may further include a fourth collector surface (404) facing the end of the extension recess (800). The depth of the extension recess (800) may be changed in various designs within a range smaller than the distance between the second collector surface (402) and the third collector surface (403).

[0213] Below, a secondary battery (2) according to a fourth embodiment of the present invention will be described.

[0214] The secondary battery (2) according to the present embodiment may be configured to differ from the secondary battery (2) according to the third embodiment of the present invention only in the detailed configuration of the terminal (600).

[0215] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the terminal (600) different from that of the secondary battery (2) according to the third embodiment of the present invention will be described.

[0216] The description of the secondary battery (2) according to the third embodiment of the present invention can be applied as is to the remaining configuration of the secondary battery (2) according to the present embodiment.

[0217] Figure 21 is a drawing schematically showing the configuration of a secondary battery according to the fourth embodiment of the present invention.

[0218] The terminal (600) according to the present embodiment may further include a terminal filler (630).

[0219] The terminal filler (630) can function as a configuration for securing the welding thickness of the terminal (600) to the first collector plate (400). More specifically, the terminal filler (630) can secure the welding thickness of the terminal (600) to the first collector plate (400) by being configured to compensate for the thickness reduction of the first terminal (610) due to the terminal recess (611) and the guide recess (612).

[0220] The terminal filler (630) according to the present embodiment may protrude from the outer surface of the first terminal (610) facing the second terminal (620) toward the second terminal (620). The central axis of the terminal filler (630) may be positioned coaxially with the central axis of the guide filler (420). The terminal filler (630) of the terminal filler (630) may be inserted into the interior of the second terminal (620).

[0221] The height of the terminal filler (630) can be designed in various ways within a range that is equal to the sum of the depths of the terminal recess (611) and the guide recess (612), or less than the sum of the depths of the terminal recess (611) and the guide recess (612).

[0222] In addition, in FIG. 21, the area of ​​the terminal filler (630) is illustrated as being the same as the area of ​​the guide recess (612) and the guide filler (420), but the present invention is not limited thereto, and the area of ​​the terminal filler (630) may be formed to be larger than the area of ​​the guide recess (612) and the guide filler (420).

[0223] Below, a secondary battery (2) according to a fifth embodiment of the present invention will be described.

[0224] The secondary battery (2) according to the present embodiment may be configured to differ from the secondary battery (2) according to the first to fourth embodiments of the present invention only in the detailed configuration of the first collector plate (400).

[0225] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the first collector plate (400) that is different from the secondary battery (2) according to the first to fourth embodiments of the present invention will be described.

[0226] For the remaining configuration of the secondary battery (2) according to the present embodiment, the description of the secondary battery (2) according to the first to fourth embodiments of the present invention can be applied as is.

[0227] Fig. 22 is a drawing schematically showing the configuration of a first collector plate according to a fifth embodiment of the present invention.

[0228] Referring to FIG. 4 and FIG. 22, the first collector plate (400) according to the present embodiment may further include a fuse hole (430).

[0229] The fuse hole (430) may be formed by penetrating the first collector plate (400). The fuse hole (430) may function as a configuration that physically cuts the first collector plate (400) to cut off the electrical connection between the electrode assembly (100) and the terminal (600) when an overcurrent flows into the first collector plate (400).

[0230] The fuse hole (430) according to the present embodiment may have the form of a hole penetrating the first collector surface (401) and the second collector surface (402) on the outside of the recess (700). The fuse hole (430) may be provided in multiple numbers. The multiple fuse holes (430) may be arranged at predetermined intervals along a circumference centered on the central axis of the recess (700). Accordingly, the multiple fuse holes (430) may be arranged to surround the recess (700) on the outside of the recess (700). The number of the multiple fuse holes (430) is not limited to the shape illustrated in FIG. 22, and the design may be changed to various numbers.

[0231] Fig. 23 is a drawing showing a modified example of the fuse hole illustrated in Fig. 22.

[0232] Referring to Fig. 23, the fuse hole (430) may have a shape of a hole penetrating the third collector surface (403) and the second collector surface (402) inside the recess (700). The fuse hole (430) may be provided in multiple numbers. The multiple fuse holes (430) may be arranged at predetermined intervals along a circumference centered on the central axis of the recess (700). Accordingly, the multiple fuse holes (430) may be arranged to form an approximately circular arc shape inside the recess (700). The number of the multiple fuse holes (430) is not limited to the shape illustrated in Fig. 23, and the design may be changed to various numbers.

[0233] Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

[0234] Therefore, the technical protection scope of the present invention should be defined by the following patent claims.

Claims

1. Electrode assembly having a center hole; A case that accommodates the electrode assembly and has an opening and a closing portion; A cap plate that seals the above opening; A first collector plate disposed between the electrode assembly and the closure, and having a first collector surface facing the electrode assembly and a second collector surface facing the closure; A terminal penetrating the above-mentioned closed portion and connected to the first collector plate; and A secondary battery characterized by including a recess formed concavely from the first front surface toward the second front surface and positioned to face the center hole.

2. In paragraph 1, A secondary battery characterized in that the area of ​​the recess is larger than the area of ​​the center hole.

3. In paragraph 1, A secondary battery characterized in that the depth of the recess is 0.3 mm or more and 2 mm or less.

4. In paragraph 1, A secondary battery characterized in that the central axis of the recess and the central axis of the center hole are coaxially located.

5. In paragraph 1, The first collector plate includes a filler that protrudes from the second collector surface toward the terminal and comes into contact with the terminal; A secondary battery characterized in that the recess is arranged inside the filler.

6. In paragraph 5, The above terminal, A first terminal surface disposed inside the case and facing the second collector surface; A second terminal surface spaced apart from the first terminal surface and arranged on the outside of the case; and including a terminal recess formed concavely from the first terminal surface toward the second terminal surface; A secondary battery characterized in that the above filler is inserted into the inside of the terminal recess.

7. In paragraph 6, A secondary battery characterized in that the depth of the terminal recess is smaller than the height of the filler.

8. In paragraph 6, A secondary battery characterized in that the area of ​​the terminal recess is larger than the area of ​​the filler.

9. In paragraph 8, A secondary battery characterized in that the distance between the outer surface of the filler and the inner surface of the terminal recess is 0.1 mm or more and 10 mm or less.

10. In paragraph 6, The above terminal, A third terminal surface facing the end of the terminal recess; and Further comprising a guide recess formed concavely from the third terminal surface toward the second terminal surface and connected to the terminal recess; A secondary battery characterized in that the first collector plate further includes a guide filler protruding from the filler and inserted into the guide recess.

11. In paragraph 10, A secondary battery characterized in that the central axis of the guide filler and the central axis of the filler are coaxially located.

12. In paragraph 10, A secondary battery characterized in that the outer surface of the above guide filler is in contact with the inner surface of the above guide recess.

13. In paragraph 10, The above first collector plate further includes a third collector front surface facing the end of the recess; A secondary battery further characterized by including an extension recess formed concavely inwardly from the third front surface of the guide filler and connected to the recess.

14. In paragraph 10, The above terminal, A first terminal coupled to the above closure and having the first terminal surface; A second terminal connected to the first terminal and having the second terminal surface; and A secondary battery further comprising a terminal filler extending from the first terminal and inserted into the second terminal.

15. In paragraph 14, A secondary battery characterized in that the central axis of the above guide filler and the central axis of the above terminal filler are coaxially located.

16. In paragraph 1, A secondary battery further comprising one or more fuse holes formed through the first collector plate.

17. In paragraph 1, A secondary battery further comprising a second collector plate disposed between the electrode assembly and the cap plate.

18. Housing; A plurality of secondary batteries arranged inside the housing; and A bus bar connecting a plurality of the secondary batteries is included; The above secondary battery, An electrode assembly having a center hole; A case that accommodates the electrode assembly and has an opening and a closing portion; A cap plate that seals the above opening; A first collector plate disposed between the electrode assembly and the closure, and having a first collector surface facing the electrode assembly and a second collector surface facing the closure; A terminal penetrating the above-mentioned closed portion and connected to the first collector plate; and A battery pack characterized by including a recess formed concavely from the first front surface toward the second front surface and positioned to face the center hole.

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