Secondary battery and battery pack including same

Abstract

The present invention relates to a secondary battery and a battery pack including same, and addresses the technical problem of providing a secondary battery that can improve the bonding strength between components and electrical output characteristics, and a battery pack including same. To this end, the present invention provides a secondary battery comprising: an electrode assembly; a case that accommodates the electrode assembly and has an opening portion and a closed portion; a cap plate that seals the opening portion; a terminal that passes through the closed portion and is provided with a first terminal surface and a second terminal surface spaced apart from each other along a first direction; a first current collecting plate disposed between the electrode assembly and the first terminal surface; a recess formed concavely along the first direction from the first terminal surface; and a filler extending from the first current collecting plate and inserted into the recess.

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 and a battery pack including the same that can improve the bonding strength and electrical output characteristics between components.

[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] A secondary battery according to the present invention for solving the above technical problem comprises: an electrode assembly; a case that accommodates the electrode assembly and has an opening and a closing portion; a cap plate that seals the opening portion; a terminal that penetrates the closing portion and has a first terminal surface and a second terminal surface spaced apart from each other along a first direction; a first current collector plate disposed between the electrode assembly and the first terminal surface; a recess formed concavely from the first terminal surface along the first direction; and a filler extending from the first current collector plate and inserted into the recess.

[0008] The outer surface of the above filler can be in contact with the inner surface of the above recess.

[0009] The length of the recess parallel to the first direction may be smaller than the length between the first terminal surface and the second terminal surface.

[0010] The terminal includes a terminal cap having a first cap surface facing the recess and the first direction and a second cap surface opposite to the first cap surface; wherein the first cap surface can be in contact with a first contact surface disposed at an end of the filler.

[0011] The above first cap surface can be arranged parallel to the above first contact surface.

[0012] The terminal cap and the filler can be joined by a weld extending from the second cap surface toward the first contact surface.

[0013] The height of the second cap surface may be lower than the height of the second terminal surface.

[0014] The terminal further includes a groove arranged to face the second cap surface, and an end of the welding portion may be arranged inside the groove.

[0015] It may further include a flange extending from the outer surface of the filler in a second direction intersecting the first direction and having a second contact surface that comes into contact with the first cap surface.

[0016] The first contact surface and the second contact surface may be arranged on the same plane.

[0017] The end of the above filler can penetrate the second terminal surface.

[0018] The first contact surface disposed at the end of the above filler may be disposed on the same plane as the second terminal surface.

[0019] The terminal and the filler can be joined by a welding portion disposed between the outer surface of the filler and the inner surface of the recess.

[0020] The welding part may further include a first groove formed concavely from an end of the filler; and a second groove formed concavely from the second terminal surface and connected to the first groove; wherein the end of the welding part may be arranged inside the first groove and the second groove.

[0021] It may further include a flange having a second contact surface that extends from the outer surface of the filler in a second direction intersecting the first direction and is arranged on the same plane as the first contact surface that is arranged at the end of the filler.

[0022] It may further include a thread protruding from the outer surface of the above filler and screwed into the inner surface of the above recess.

[0023] It may further include a guide groove formed concavely on the inside of one of the recess and the filler; and a guide rail protruding from the other of the recess and the filler and inserted into the guide groove.

[0024] The above guide home and the above guide rail can extend along the first direction.

[0025] It may further include a second collector plate disposed between the electrode assembly and the cap plate.

[0026] A battery pack according to the present invention comprises: a housing; a plurality of secondary batteries arranged inside the housing; and a bus bar connecting the plurality of secondary batteries; wherein the secondary battery comprises: an electrode assembly; a case accommodating the electrode assembly and having an opening and a closing portion; a cap plate sealing the opening portion; a terminal penetrating the closing portion and having a first terminal surface and a second terminal surface spaced apart from each other along a first direction; a first current collector plate arranged between the electrode assembly and the first terminal surface; a recess formed concavely from the first terminal surface along the first direction; and a filler extending from the first current collector plate and inserted into the recess.

[0027] According to the present invention, since a filler is formed that is directly inserted into the inside of the terminal and bonded to the terminal, a stable bonding strength can be secured by increasing the welding area between the terminal and the first collector plate compared to a case where a welding tool is inserted into the inside of a conventional terminal to perform welding work.

[0028] According to the present invention, the filler is exposed to the outside of the terminal and directly connected to the bus bar, thereby lowering the cell resistance and improving the output characteristics.

[0029] 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.

[0030] 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.

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

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

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

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

[0035] FIG. 5 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to the first embodiment of the present invention.

[0036] FIG. 6 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to the first embodiment of the present invention.

[0037] FIG. 7 is a drawing schematically showing the connection structure of a secondary battery and a first branch bus bar according to a first embodiment of the present invention.

[0038] Figure 8 is a drawing schematically showing the configuration of a secondary battery according to a second embodiment of the present invention.

[0039] FIG. 9 is a drawing schematically showing the connection structure of a secondary battery and a first branch bus bar according to a second embodiment of the present invention.

[0040] FIG. 10 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a third embodiment of the present invention.

[0041] FIG. 11 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to a third embodiment of the present invention.

[0042] Figure 12 is a drawing schematically showing a state in which a weld is formed in a secondary battery according to a third embodiment of the present invention.

[0043] FIG. 13 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a fourth embodiment of the present invention.

[0044] FIG. 14 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to a fourth embodiment of the present invention.

[0045] FIG. 15 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a fifth embodiment of the present invention.

[0046] Fig. 16 is a cross-sectional view taken along line 16-16' of Fig. 15, and Fig. 17 is a cross-sectional view taken along line 17-17' of Fig. 15.

[0047] FIG. 18 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to a fifth embodiment of the present invention.

[0048] Figure 19 is a perspective view schematically showing the configuration of a secondary battery according to the sixth embodiment of the present invention.

[0049] Figure 20 is a plan view schematically showing the configuration of a secondary battery according to the sixth embodiment of the present invention.

[0050] Figure 21 is a cross-sectional view schematically showing the configuration of a secondary battery according to the sixth embodiment of the present invention.

[0051] FIG. 22 is a drawing schematically showing the connection structure of a secondary battery and a first branch bus bar according to the sixth embodiment of the present invention.

[0052] FIG. 23 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to the seventh embodiment of the present invention.

[0053] FIG. 24 is a drawing showing a state in which a filler is inserted into a recess in a secondary battery according to the seventh embodiment of the present invention.

[0054] Figure 25 is a drawing showing a state in which a weld is formed in a secondary battery according to the seventh embodiment of the present invention.

[0055] Fig. 26 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to the eighth embodiment of the present invention.

[0056] Figure 27 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to the eighth embodiment of the present invention.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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).

[0074] The housing (1) forms the outline of the battery pack and can provide a space in which a secondary battery (2) can be accommodated.

[0075] The housing (1) according to the present embodiment may include a housing body (11) and a cover (12).

[0076] 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.

[0077] 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.

[0078] A secondary battery (2) can function as a unit structure that stores and supplies power in a battery pack.

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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.

[0083] The first branch bus bar (32) can extend from the main bus bar (31) toward the terminal (400) of the secondary battery (2) described later. The first branch bus bar (32) can be mechanically and electrically connected to the terminal (400) by laser welding, ultrasonic welding, or the like.

[0084] The second branch bus bar (33) can extend from the main bus bar (31) toward the closing section (203) of the secondary battery (2) described later. The second branch bus bar (33) can be mechanically and electrically connected to the closing section (203) by laser welding, ultrasonic welding, or the like.

[0085] Below, a secondary battery (2) according to various embodiments of the present invention will be described.

[0086] FIG. 3 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, and FIG. 4 is a cross-sectional view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention.

[0087] Referring to FIGS. 3 and 4, the secondary battery (2) according to the present embodiment includes an electrode assembly (100), a case (200), a cap plate (300), a terminal (400), a first collector plate (500), a recess (700), and a filler (800).

[0088] 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.

[0089] The electrode assembly (100) can function as a unit structure that performs charging and discharging operations of power in a secondary battery.

[0090] 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).

[0091] The electrode assembly (100) may have a wound shape centered on the winding axis (C).

[0092] 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).

[0093] 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.

[0094] 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).

[0095] As the first electrode plate (110) functions as an anode, the first active material layer may include a cathode active material.

[0096] 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.

[0097] 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.

[0098] The first active material layer may further include a positive electrode conductive material.

[0099] 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.

[0100] The first active material layer may further include a positive electrode binder.

[0101] 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).

[0102] Examples of positive binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] The first electrode plate (110) may include a first non-coated portion (111) on which the first active material layer is not applied. The first non-coated portion (111) may protrude a predetermined distance from one end of the electrode assembly (100) along the winding axis (C).

[0108] 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.

[0109] 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.

[0110] 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).

[0111] As the second electrode plate (120) functions as a cathode, the second active material layer may include a cathode active material.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] The second active material layer may further include a negative electrode conductive material and a negative electrode binder.

[0120] The negative 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 positive 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.

[0121] 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).

[0122] Examples of cathode binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] The second electrode plate (120) may include a second non-coated portion (121) on which a second active material layer is not applied. The second non-coated portion (121) may protrude a predetermined distance from the other end of the electrode assembly (100) located on the opposite side of the first non-coated portion (111) along the winding axis (C).

[0128] 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).

[0129] 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.

[0130] 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.

[0131] 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.

[0132] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0133] 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.

[0134] 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.

[0135] 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).

[0136] 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.

[0137] The case (200) may include a can (201), an opening (202), and a closing portion (203).

[0138] 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).

[0139] 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).

[0140] The opening portion (202) and the closing portion (203) may be respectively positioned at both ends of the can (201). The opening portion (202) and the closing portion (203) may be positioned spaced apart from each other along a first direction. The first direction described below may refer to a direction from the opening portion (202) toward the closing portion (203) with reference to FIG. 4 among directions parallel to the central axis of the can (201) and the winding axis (C) of the electrode assembly (100).

[0141] 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.

[0142] The closure portion (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 portion (202) in the first direction. The outer circumference of the closure portion (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 portion (203) may be formed by a deep drawing process. Alternatively, the closure portion (203) may be manufactured separately from the can (201), and the outer circumference may be joined to the inner circumference of the can (201).

[0143] 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).

[0144] 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).

[0145] 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.

[0146] The case (200) according to the present embodiment may further include a beading portion (204).

[0147] 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).

[0148] The cap plate (300) can be configured to seal the opening (202) of the case (200).

[0149] 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).

[0150] 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).

[0151] A cap gasket (G0) that electrically insulates the cap plate (300) and the case (200) may be placed between the cap plate (300) and the crimping portion (205).

[0152] The cap gasket (G0) 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 (G0) may be press-fixed to the inner surface of the beading portion (204) and the crimping portion (205). The cap gasket (G0) may be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like. Accordingly, the cap gasket (G0) 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).

[0153] The crimping portion (205) is positioned to face the other surface of the cap plate (300) with the cap gasket (G0) interposed therebetween, and can press the cap plate (300) toward the beading portion (204) by coming into contact with the cap gasket (G0). Accordingly, the cap plate (300) can be stably fixed on the opening portion (202) side of the case (200).

[0154] 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.

[0155] 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.

[0156] 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.

[0157] The terminal (400) is coupled to the case (200) and can be electrically connected to the electrode assembly (100) by the first collector plate (500) and filler (800) described later. The terminal (400) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0158] In this embodiment, the terminal (400) can function as a positive terminal of the secondary battery (2) by being electrically connected to the first electrode plate (110) of the electrode assembly (100) by the first collector plate (500) and the filler (800). However, the terminal (400) is not limited thereto, and can also function as a negative terminal by being electrically connected to the second electrode plate (120).

[0159] FIG. 5 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a first embodiment of the present invention, and FIG. 6 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to a first embodiment of the present invention.

[0160] Referring to FIGS. 1 to 6, the terminal (400) according to the present embodiment can penetrate the closing portion (203) of the case (200) along the first direction. Both sides of the terminal (400) can be placed in the internal space and external space of the can (201), respectively.

[0161] A first terminal surface (401) facing the electrode assembly (100) along a first direction may be formed on one side of a terminal (400) located in the internal space of the can (201). The first terminal surface (401) according to the present embodiment may have a planar shape that is arranged perpendicular to the first direction. One side of the terminal (400) located in the internal space of the can (201) may be formed so that the cross-sectional area increases toward the first terminal surface (401). One side of the terminal (400) may be compressed and deformed by riveting after being inserted into the internal space of the can (201) and may be formed so that the cross-sectional area increases toward the first terminal surface (401).

[0162] A second terminal surface (402) may be formed on the other side of the terminal (400) located in the external space of the can (201) and spaced apart from the first terminal surface (401) in the first direction. The second terminal surface (402) according to the present embodiment may have a planar shape that faces the external space of the can (201) and is arranged parallel to the first terminal surface (401). The terminal (400) may have a structure in which cross-sectional areas on both sides with respect to the closing portion (203) are different. In this case, the cross-sectional area of ​​the second terminal surface (402) may be larger than the cross-sectional area of ​​the first terminal surface (401). Accordingly, the terminal (400) may be prevented from being separated into the interior of the case (200) through the through hole formed in the closing portion (203).

[0163] A first terminal gasket (G1) and a second terminal gasket (G2) that electrically insulate the terminal (400) and the case (200) may be placed between the terminal (400) and the case (200).

[0164] The first terminal gasket (G1) according to the present embodiment can be arranged to surround the inner peripheral surface area of ​​the closure portion (203) through which the terminal (400) passes. Both sides of the first terminal gasket (G1) can be tightly fixed to the outer peripheral surface of the terminal (400) and the inner peripheral surface of the closure portion (203), respectively.

[0165] The second terminal gasket (G2) according to the present embodiment can be tightly fixed between the upper surface of the closing portion (203) positioned so as to face the external space of the case (200) and the lower surface of the other side of the terminal (400) protruding outward from the closing portion (203).

[0166] The first terminal gasket (G1) and the second terminal gasket (G2) can be formed of an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0167] The first collector plate (500) is placed between the electrode assembly (100) and the first terminal surface (401) and can be connected to the electrode assembly (100). The first collector plate (500) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0168] The first collector plate (500) according to the present embodiment is formed to have a shape roughly like a circular plate, and can be placed between one surface of the electrode assembly (100) from which the first non-conductive portion (111) protrudes and the first terminal surface (401). The area of ​​the first collector plate (500) may be the same as the area of ​​one surface of the electrode assembly (100), or may be smaller than the area of ​​one surface of the electrode assembly (100). The central axis of the first collector plate (500) may be positioned coaxially with the winding axis (C) of the electrode assembly (100).

[0169] Both sides of the first collector plate (500) can be arranged to face one side of the electrode assembly (100) from which the first non-conductive portion (111) protrudes and the first terminal surface (401), respectively.

[0170] One side of the first collector plate (500) can be connected to the first non-coated portion (111) protruding from one side of the electrode assembly (100). Accordingly, in the present embodiment, the first collector plate (500) can function as a positive electrode collector plate. An end of the first non-coated portion (111) can be bent in a direction parallel to the first collector plate (500) and connected to one side of the first collector plate (500) by welding or the like. The bending direction of the first non-coated portion (111) can be a direction toward the winding axis (C) of the electrode assembly (100).

[0171] The other surface of the first collector plate (500) is in contact with the first terminal surface (401) and can be electrically connected to the terminal (400). Accordingly, the first collector plate (500) can electrically connect the first electrode plate (110) and the terminal (400). However, the first collector plate (500) is not limited thereto, and it is also possible to configure the other surface of the first collector plate (500) to be separated from the first terminal surface (401).

[0172] The secondary battery (2) according to the present embodiment may further include a second collector plate (600).

[0173] The second collector plate (600) 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 (600) can be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0174] The second collector plate (600) according to the present embodiment may include a flat portion (610) facing the other surface of the electrode assembly (100) from which the second non-conductive portion (121) protrudes, and an extension portion (620) extending from the flat portion (610).

[0175] One side of the flat portion (610) facing the other side of the electrode assembly (100) can be connected to the second non-coated portion (121). Accordingly, in the present embodiment, the second collector plate (600) can function as a negative electrode collector plate. An end of the second non-coated portion (121) can be bent in a direction parallel to the flat portion (610) and connected to one side of the flat portion (610) by welding or the like. The bending direction of the second non-coated portion (121) can be a direction toward the winding axis (C) of the electrode assembly (100).

[0176] The extension portion (620) may extend from the edge of the flat portion (610) toward the cap plate (300). The extension portion (620) may contact the inner surface of the bead portion (204). The extension portion (620) may be rounded or bent along the bead portion (204). The extension portion (620) may be connected to the bead portion (204) by welding or the like. Accordingly, the case (200) and the second electrode plate (120) are electrically connected, and the closing portion (203) may function as a negative terminal.

[0177] The extension portion (620) may be formed in multiple pieces. The multiple extension portions (620) may be arranged spaced apart from each other along the edge of the flat portion (610).

[0178] The recess (700) may be provided in the terminal (400) and configured to provide a space in which a filler (800) can be accommodated inside the terminal (400).

[0179] 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).

[0180] The recess (700) according to the present embodiment may have a groove shape that is concavely formed inwardly of the terminal (400) along the first direction from the first terminal surface (401). The central axis of the recess (700) may be positioned coaxially with the winding axis (C) of the terminal (400) and the electrode assembly (100). The cross-sectional shape of the recess (700) may be formed to correspond to the cross-sectional shape of the filler (800) described below.

[0181] In this embodiment, the length of the recess (700) parallel to the first direction may be smaller than the length between the first terminal surface (401) and the second terminal surface (402).

[0182] Accordingly, the terminal (400) according to the present embodiment may include a terminal cap (410) having a first cap surface (411) facing an end of a recess (700) and a second cap surface (412) opposite to the first cap surface (411).

[0183] The terminal cap (410) may be formed integrally with the terminal (400), or alternatively, it may be manufactured separately from the terminal (400) and joined to the terminal (400) by welding or the like.

[0184] The first cap surface (411) according to the present embodiment may have a planar shape that is arranged perpendicular to the first direction. The area of ​​the first cap surface (411) may be formed to have the same area as the area of ​​the end of the recess (700).

[0185] The second cap surface (412) according to the present embodiment may be spaced apart from the first cap surface (411) by a predetermined distance in the first direction. The second cap surface (412) may be arranged parallel to the second terminal surface (402). The second cap surface (412) may be arranged on the same plane as the second terminal surface (402). That is, the height of the second cap surface (412) may be the same as the height of the second terminal surface (402). Accordingly, the second terminal surface (402) and the second cap surface (412) may be formed to form a single plane that is continuously connected.

[0186] The filler (800) extends from the first collector plate (500) and can be inserted into the recess (700). The filler (800) can function as a component that provides mechanical and electrical connection between the terminal (400) and the first collector plate (500).

[0187] The filler (800) according to the present embodiment may have the shape of a pillar extending from the first collector plate (500) in the first direction. The filler (800) may be formed of a material having the same electrical conductivity as the first collector plate (500). The filler (800) may be formed integrally with the first collector plate (500), or alternatively, it may be manufactured separately from the first collector plate (500) and then joined to the first collector plate (500) by welding or the like.

[0188] The central axis of the filler (800) may be positioned coaxially with the central axis of the recess (700). The filler (800) may be inserted into the interior of the recess (700) through one end of the recess (700) penetrating the first terminal surface (401). The outer circumference of the filler (800) may be in contact with the inner circumference of the recess (700). Accordingly, the filler (800) may not flow inside the recess (700) due to external impact, vibration, etc.

[0189] A first contact surface (810) may be formed at an end of the filler (800). The first contact surface (810) may come into contact with the first cap surface (411) of the terminal cap (410) as the filler (800) is fully inserted into the recess (700).

[0190] The first contact surface (810) according to the present embodiment may have a shape of a plane that is arranged perpendicular to the first direction. That is, the first cap surface (411) and the first contact surface (810) may be arranged parallel to each other. Accordingly, the first contact surface (810) may expand the contact area with the first cap surface (411), thereby lowering the cell resistance of the secondary battery (2) and improving the bonding strength by the welding portion (W) described below.

[0191] The terminal (400) and the filler (800) can be mutually joined by a welding part (W).

[0192] The weld (W) according to the present embodiment may extend from the second cap surface (412) of the terminal cap (410) toward the first contact surface (810). The weld (W) may be formed by laser welding. More specifically, the weld (W) may be exemplified as a mixture of the terminal cap (410) and the filler (800) that are melted and integrally joined by a laser beam irradiated from a laser welding device (not shown) toward the second cap surface (412).

[0193] The length of the weld (W) parallel to the first direction may be greater than the length between the second cap surface (412) and the first contact surface (810). The cross-sectional area of ​​the weld (W) perpendicular to the first direction can be variously designed and changed within the range of the areas of the first cap surface (411) and the first contact surface (810). Accordingly, the secondary battery (2) according to the present embodiment can lower the cell resistance and improve the output characteristics by increasing the welding area between the terminal (400) and the first collector plate (500) compared to the case where the welding work is performed on the inside of the existing terminal (400).

[0194] FIG. 7 is a drawing schematically showing the connection structure of a secondary battery and a first branch bus bar according to a first embodiment of the present invention.

[0195] Referring to Fig. 7, the first branch bus bar (32) can be mounted on the second terminal surface (402) and the second cap surface (412). The first branch bus bar (32) can be integrally joined to the second terminal surface (402) and the second cap surface (412) by laser welding, ultrasonic welding, or the like. Accordingly, the secondary battery (2) according to the present embodiment can lower cell resistance and improve output characteristics by expanding the contact area between the terminal (400) and the first branch bus bar (32) by the terminal cap (410).

[0196] Below, a secondary battery (2) according to a 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 terminal (400).

[0198] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the terminal (400) different from that of the secondary battery (2) according to the first embodiment of the present invention will be described.

[0199] 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.

[0200] FIG. 8 is a drawing schematically showing the configuration of a secondary battery according to a second embodiment of the present invention, and FIG. 9 is a drawing schematically showing the connection structure of a secondary battery and a first branch bus bar according to a second embodiment of the present invention.

[0201] Referring to FIGS. 8 and 9, the height of the second cap surface (412) according to the present embodiment may be lower than the height of the second terminal surface (402). That is, in the present embodiment, the second cap surface (412) may not be positioned on the same plane as the second terminal surface (402), but may be positioned at a predetermined distance from the second terminal surface (402) in the opposite direction to the first direction.

[0202] Accordingly, the terminal (400) according to the present embodiment may be configured to further include a groove (420) positioned facing the second cap surface (412).

[0203] The groove (420) according to the present embodiment may have a shape of a groove that is concavely formed in a direction opposite to the first direction from the second terminal surface (402). The groove (420) may be arranged to face the second cap surface (412) along the first direction. The area of ​​the groove (420) may be formed to be the same as the area of ​​the second cap surface (412).

[0204] In the process of forming the weld (W), the welding bead (B) formed at the end of the weld (W) can be placed inside the groove (420).

[0205] Accordingly, when the welding bead (B) protrudes outward from the second cap surface (412) due to welding conditions or external environmental factors during the formation of the welded portion (W), the groove (420) prevents the welding bead (B) from protruding beyond the second terminal surface (402), thereby inducing stable contact between the first branch bus bar (32) and the terminal (400).

[0206] Below, a secondary battery (2) according to a third embodiment of the present invention will be described.

[0207] FIG. 10 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a third embodiment of the present invention, FIG. 11 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to a third embodiment of the present invention, and FIG. 12 is a drawing schematically showing a state in which a weld is formed in a secondary battery according to a third embodiment of the present invention.

[0208] Referring to FIGS. 10 to 12, the secondary battery (2) according to the present embodiment may further include a flange (820).

[0209] The secondary battery (2) according to the present embodiment may be configured to differ only in the secondary battery (2) according to the first and second embodiments of the present invention from the flange (820) and in the detailed configuration of the recess (700).

[0210] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the flange (820) and the recess (700) that were not described in the secondary battery (2) according to the first and second embodiments of the present invention will be described.

[0211] For the remaining configuration of the secondary battery (2) according to the present embodiment, the description of the secondary battery (2) according to the first and second embodiments of the present invention can be applied as is.

[0212] The flange (820) according to the present embodiment may extend from the outer surface of the filler (800) along a second direction intersecting the first direction. In the present embodiment, the second direction may mean a direction perpendicular to the first direction and parallel to the radial direction of the filler (800). The flange (820) may be formed to have an approximately circular plate shape. However, the cross-sectional shape of the flange (820) is not limited thereto, and may be formed to have various shapes such as a polygon or an oval. The flange (820) may be arranged at an end of the filler (800). A second contact surface (830) arranged on the same plane as the first contact surface (810) may be formed on one surface of the flange (820). Accordingly, the cross-sectional shapes of the filler (800) and the flange (820) parallel to the first direction may be formed to form a T shape.

[0213] The recess (700) according to the present embodiment may include an extension recess (701). The extension recess (701) may have a groove shape that is concavely formed in a direction parallel to the second direction from the recess (700) toward the inside of the terminal (400). The extension length, height, etc. of the extension recess (701) may be formed to be the same as the extension length, height, etc. of the flange (820).

[0214] The area of ​​the first cap surface (411) according to the present embodiment can be formed to be equal to the sum of the areas of the recess (700) and the extension recess (710).

[0215] The filler (800) and flange (820) according to the present embodiment can be inserted into the recess (700) by a method of manufacturing the terminal (400) in segments. That is, the filler (800) and flange (820) according to the present embodiment can be inserted into the recess (700) after the terminal (400) is segmented in a direction parallel to the first direction, and fixed inside the recess (700) by a method of assembling or joining each part of the segmented terminal (400) together.

[0216] The area of ​​the weld (W) according to the present embodiment can be variously designed and changed within a range that is larger than the area of ​​the first contact surface (810) and smaller than the sum of the areas of the first contact surface (810) and the second contact surface (830). Accordingly, the secondary battery (2) according to the present embodiment can improve the bonding strength between the terminal (400) and the filler (800) by relatively expanding the area of ​​the weld (W) compared to the secondary batteries (2) according to the first and second embodiments of the present invention.

[0217] In FIGS. 10 to 12, the terminal (400) is illustrated as an example in which the terminal does not include a groove (420), but the present embodiment is not limited thereto, and the terminal (400) may also be configured to include a groove (420).

[0218] Below, a secondary battery (2) according to a fourth embodiment of the present invention will be described.

[0219] FIG. 13 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a fourth embodiment of the present invention, and FIG. 14 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to a fourth embodiment of the present invention.

[0220] Referring to FIGS. 13 and 14, the secondary battery according to the present embodiment may further include a thread (840).

[0221] The secondary battery (2) according to the present embodiment can be configured to differ only in that it further includes a thread (840) from the secondary battery (2) according to the first and second embodiments of the present invention.

[0222] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the thread (840) that was not described in the secondary battery (2) according to the first and second embodiments of the present invention will be described.

[0223] For the remaining configuration of the secondary battery (2) according to the present embodiment, the description of the secondary battery (2) according to the first and second embodiments of the present invention can be applied as is.

[0224] The thread (840) protrudes from the outer surface of the filler (800) and can be screw-connected to the inner surface of the recess (700).

[0225] The thread (840) according to the present embodiment may be formed to have a screw thread shape that protrudes in a second direction from the outer surface of the filler (800) and extends in a spiral shape along the first direction. The thread (840) may be screw-connected to the inner surface of the recess (700) by rotation of the filler (800) during the process of inserting the filler (800) into the recess (700).

[0226] Accordingly, the secondary battery (2) according to the present embodiment can prevent the filler (800) from flowing inside the recess (700) or from being separated from the recess (700) due to external vibration, impact, etc.

[0227] In FIGS. 13 and 14, the terminal (400) is illustrated as an example in which the terminal does not include a groove (420), but the present embodiment is not limited thereto, and the terminal (400) may also be configured to include a groove (420).

[0228] Below, a secondary battery (2) according to a fifth embodiment of the present invention will be described.

[0229] FIG. 15 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a fifth embodiment of the present invention, FIG. 16 is a cross-sectional view taken along line 16-16' of FIG. 15, FIG. 17 is a cross-sectional view taken along line 17-17' of FIG. 15, and FIG. 18 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to a fifth embodiment of the present invention.

[0230] Referring to FIGS. 15 to 18, the secondary battery (2) according to the present embodiment may include a guide groove (R1) and a guide rail (R2).

[0231] The guide home (R1) and guide rail (R2) are provided between the recess (700) and the filler (800) to guide the insertion motion of the filler (800) and can function as a configuration that limits the rotation of the filler (800).

[0232] Hereinafter, an example will be described in which a guide groove (R1) is formed in a recess (700) and a guide rail (R2) is formed in a filler (800). However, the guide groove (R1) and the guide rail (R2) are not limited thereto, and it is also possible for the guide groove (R1) to be formed in a filler (800) and the guide rail (R2) to be formed in a recess (700).

[0233] The guide groove (R1) according to the present embodiment may be formed concavely along the second direction from the inner surface of the recess (700). The guide groove (R1) may extend longitudinally along the first direction. The guide groove (R1) may be provided in multiple numbers. The multiple guide grooves (R1) may be arranged at predetermined intervals along the inner surface of the recess (700) with the central axis of the recess (700) as the center.

[0234] The guide rail (R2) according to the present embodiment may protrude from the outer surface of the filler (800) in a second direction. The guide rail (R2) may extend in the longitudinal direction along the first direction. The guide rail (R2) may be provided in multiple numbers. The multiple guide rails (R2) may be arranged at predetermined intervals along the outer surface of the filler (800) with the central axis of the filler (800) as the center.

[0235] As the filler (800) is inserted into the recess (700), the guide rail (R2) can be inserted into the guide groove (R1). During the insertion process of the filler (800), the guide rail (R2) can be moved in a first direction along the guide groove (R1) and the movement direction of the filler (800) can be aligned with the central axis of the recess (700). Thereafter, when the filler (800) is inserted into the recess (700), the guide rail (R2) can contact both sides of the guide groove (R1) to restrict the filler (800) from rotating around the central axis. Accordingly, the guide rail (R2) can prevent the welding strength of the terminal (400) and the filler (800) from being reduced due to the rotation of the filler (800) during the formation process of the welded portion (W).

[0236] In FIGS. 15 to 18, the terminal (400) is illustrated as an example in which the terminal does not include a groove (420), but the present embodiment is not limited thereto, and the terminal (400) may also be configured to include a groove (420).

[0237] Below, a secondary battery (2) according to the sixth embodiment of the present invention will be described.

[0238] The secondary battery (2) according to the present embodiment can be configured to differ only in the detailed configuration of the terminal (400) and the filler (800) from the secondary battery (2) according to the first embodiment of the present invention.

[0239] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the terminal (400) and filler (800) that were not described in the secondary battery (2) according to the first embodiment of the present invention will be described.

[0240] 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.

[0241] FIG. 19 is a perspective view schematically showing the configuration of a secondary battery according to a sixth embodiment of the present invention, FIG. 20 is a plan view schematically showing the configuration of a secondary battery according to a sixth embodiment of the present invention, FIG. 21 is a cross-sectional view schematically showing the configuration of a secondary battery according to a sixth embodiment of the present invention, and FIG. 22 is a drawing schematically showing the connection structure of a secondary battery and a first branch bus bar according to a sixth embodiment of the present invention.

[0242] Referring to FIGS. 19 to 22, the end of the filler (800) according to the present embodiment can penetrate the second terminal surface (402). That is, in the present embodiment, the terminal cap (410) is deleted, and the first contact surface (810) formed at the end of the filler (800) can be formed to be directly exposed to the outside of the terminal (400) through the second terminal surface (402).

[0243] Accordingly, when the first branch bus bar (32) is connected to the terminal (400), the first contact surface (810) can be in direct contact with the first branch bus bar (32) and connected to the first branch bus bar (32). Accordingly, the secondary battery (2) according to the present embodiment can reduce cell resistance and improve output characteristics by directly connecting the first branch bus bar (32) to the filler (800) formed integrally with the first collector plate (500).

[0244] The first contact surface (810) formed at the end of the filler (800) can be arranged on the same plane as the second terminal surface (402). Accordingly, the first branch bus bar (32) can be uniformly contacted across the entire first contact surface (810) and the second terminal surface (402).

[0245] The weld (W) according to the present embodiment may be arranged between the outer circumference of the filler (800) and the inner circumference of the recess (700). The weld (W) may extend in a direction opposite to the first direction from the boundary area of ​​the first contact surface (810) and the second terminal surface (402). The weld (W) may be exemplified as a mixture of the terminal (400) and the filler (800) that are melted and integrally joined by a laser beam irradiated from a laser welding device (not shown) toward the boundary area of ​​the first contact surface (810) and the second terminal surface (402).

[0246] Below, a secondary battery (2) according to the seventh embodiment of the present invention will be described.

[0247] The secondary battery (2) according to the present embodiment can be configured to differ from the secondary battery (2) according to the sixth embodiment of the present invention only in the detailed configuration of the terminal (400) and the filler (800).

[0248] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the terminal (400) and filler (800), which are different from those of the secondary battery (2) according to the sixth embodiment of the present invention, will be described.

[0249] 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.

[0250] FIG. 23 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to a seventh embodiment of the present invention, FIG. 24 is a drawing showing a state in which a filler is inserted into a recess in a secondary battery according to a seventh embodiment of the present invention, and FIG. 25 is a drawing showing a state in which a weld is formed in a secondary battery according to a seventh embodiment of the present invention.

[0251] Referring to FIGS. 23 to 25, the filler (800) according to the present embodiment may further include a first groove (860).

[0252] The first groove (860) according to the present embodiment may have a groove shape that is concavely formed in a direction opposite to the first direction from the edge area of ​​the first contact surface (810). The first groove (860) may extend in a ring shape along the edge of the first contact surface (810) with the central axis of the filler (800) as the center.

[0253] The terminal (400) according to the present embodiment may further include a second groove (430).

[0254] The second groove (430) according to the present embodiment may have a groove shape that is concavely formed in a direction opposite to the first direction from the inner peripheral edge area of ​​the second terminal face (402) positioned adjacent to the recess (700). The second groove (430) may extend to form a ring shape along the inner peripheral edge of the second terminal face (402) with the central axis of the recess (700) as the center.

[0255] As the filler (800) is inserted into the recess (700), the first groove (860) and the second groove (430) can be interconnected. That is, as illustrated in FIG. 24, the first groove (860) and the second groove (430) can have the shape of a groove that is concavely formed in the opposite direction to the first direction from the boundary area of ​​the first contact surface (810) and the second terminal surface (402).

[0256] In the process of forming the weld (W), the welding bead (B) formed at the end of the weld (W) can be placed inside the first groove (860) and the second groove (430).

[0257] Accordingly, when the welding bead (B) protrudes outward from the first contact surface (810) and the second terminal surface (402) due to welding conditions or external environmental factors during the formation of the welded portion (W), the first groove (860) and the second groove (430) can induce stable contact between the first branch bus bar (32) and the terminal (400) by preventing the welding bead (B) from protruding beyond the second terminal surface (402).

[0258] Below, a secondary battery (2) according to the eighth embodiment of the present invention will be described.

[0259] FIG. 26 is a drawing showing a state in which a terminal and a filler are separated in a secondary battery according to the eighth embodiment of the present invention, and FIG. 27 is a drawing showing a state in which a terminal and a filler are combined in a secondary battery according to the eighth embodiment of the present invention.

[0260] Referring to FIGS. 26 and 27, the secondary battery (2) according to the present embodiment may further include a flange (820).

[0261] The secondary battery (2) according to the present embodiment may be configured to differ only in the secondary battery (2) according to the sixth and seventh embodiments of the present invention and further including a flange (820) and in the detailed configuration of the recess (700).

[0262] Accordingly, in describing the secondary battery (2) according to the present embodiment, only the detailed configuration of the flange (820) and the recess (700) that were not described in the secondary battery (2) according to the 6th and 7th embodiments of the present invention will be described.

[0263] For the remaining configuration of the secondary battery (2) according to the present embodiment, the description of the secondary battery (2) according to the 6th and 7th embodiments of the present invention can be applied as is.

[0264] The flange (820) according to the present embodiment may extend from the outer surface of the filler (800) along a second direction intersecting the first direction. In the present embodiment, the second direction may mean a direction perpendicular to the first direction and parallel to the radial direction of the filler (800). The flange (820) may be formed to have an approximately circular plate shape. However, the cross-sectional shape of the flange (820) is not limited thereto, and may be formed to have various shapes such as a polygon or an oval. The flange (820) may be arranged at an end of the filler (800). A second contact surface (830) arranged on the same plane as the first contact surface (810) may be formed on one surface of the flange (820). Accordingly, the cross-sectional shapes of the filler (800) and the flange (820) parallel to the first direction may be formed to form a T shape.

[0265] The recess (700) according to the present embodiment may include an extension recess (701). The extension recess (701) may have a groove shape that is concavely formed in a direction parallel to the second direction toward the inside of the terminal (400) from the recess (700). One surface of the extension recess (701) may penetrate the second terminal surface (402) and be connected to the external space of the terminal (400). The extension length, height, etc. of the extension recess (701) may be formed to be the same as the extension length, height, etc. of the flange (820).

[0266] The filler (800) and flange (820) according to the present embodiment can be inserted into the inside of the recess (700) by splitting the terminal (400) or by press-processing the flange (820) after inserting the filler (800) into the recess (700).

[0267] The secondary battery (2) according to the present embodiment can lower the cell resistance and further improve the output characteristics by expanding the contact area between the filler (800) and the first branch bus bar (32) by the flange (820).

[0268] 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.

[0269] Therefore, the technical protection scope of the present invention should be defined by the following patent claims.

Claims

1. Electrode assembly; A case that accommodates the electrode assembly and has an opening and a closing portion; A cap plate that seals the above opening; A terminal having a first terminal surface and a second terminal surface that penetrate the above-described closed portion and are spaced apart along the first direction; A first collector plate disposed between the electrode assembly and the first terminal surface; A recess formed concavely along the first direction from the first terminal surface; and A secondary battery characterized by including a filler extending from the first collector plate and inserted into the recess.

2. In paragraph 1, A secondary battery characterized in that the outer surface of the above filler is in contact with the inner surface of the above recess.

3. In paragraph 1, A secondary battery characterized in that the length of the recess parallel to the first direction is smaller than the length between the first terminal surface and the second terminal surface.

4. In paragraph 2, The terminal includes a terminal cap having a first cap surface facing the recess and the first direction and a second cap surface opposite to the first cap surface; A secondary battery characterized in that the first cap surface is in contact with the first contact surface arranged at the end of the filler.

5. In paragraph 4, A secondary battery, characterized in that the first cap surface is arranged parallel to the first contact surface.

6. In paragraph 4, A secondary battery characterized in that the terminal cap and the filler are joined by a welding portion extending from the second cap surface toward the first contact surface.

7. In paragraph 6, A secondary battery characterized in that the height of the second cap surface is lower than the height of the second terminal surface.

8. In paragraph 7, The terminal further includes a groove arranged to face the second cap surface; A secondary battery characterized in that the end of the above welding part is placed inside the above groove.

9. In paragraph 4, A secondary battery further comprising a flange extending from the outer surface of the filler in a second direction intersecting the first direction and having a second contact surface that contacts the first cap surface.

10. In paragraph 9, A secondary battery, characterized in that the first contact surface and the second contact surface are arranged on the same plane.

11. In paragraph 1, A secondary battery characterized in that the end of the above filler penetrates the second terminal surface.

12. In paragraph 11, A secondary battery characterized in that the first contact surface disposed at the end of the above filler is disposed on the same plane as the second terminal surface.

13. In paragraph 11, A secondary battery characterized in that the terminal and the filler are joined by a welding portion disposed between the outer surface of the filler and the inner surface of the recess.

14. In paragraph 13, A first groove formed concavely from the end of the above filler; and Further comprising a second groove formed concavely from the second terminal surface and connected to the first groove; A secondary battery, characterized in that the end of the above welding part is positioned inside the first groove and the second groove.

15. In paragraph 11, A secondary battery further comprising a flange having a second contact surface that extends from the outer surface of the filler in a second direction intersecting the first direction and is arranged on the same plane as the first contact surface that is arranged at the end of the filler.

16. In paragraph 1, A secondary battery further characterized by including a thread protruding from the outer surface of the filler and screwed into the inner surface of the recess.

17. In paragraph 1, A guide groove formed concavely on the inside of one of the above recesses and the above filler; and A secondary battery further comprising a guide rail protruding from the remaining one of the recess and the filler and inserted into the guide groove.

18. In paragraph 17, A secondary battery, characterized in that the above guide home and the above guide rail extend along the first direction.

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

20. Housing; A plurality of secondary batteries arranged inside the housing; and A bus bar connecting a plurality of the secondary batteries is included; The above secondary battery, electrode assembly; A case that accommodates the electrode assembly and has an opening and a closing portion; A cap plate that seals the above opening; A terminal having a first terminal surface and a second terminal surface that penetrate the above-described closed portion and are spaced apart along the first direction; A first collector plate disposed between the electrode assembly and the first terminal surface; A recess formed concavely along the first direction from the first terminal surface; and A battery pack characterized by including a filler extending from the first collector plate and inserted into the recess.

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