Secondary battery

Abstract

The present disclosure may provide a secondary battery, comprising: a case having an opening formed in the lower portion thereof; an electrode assembly accommodated in the case and including a first electrode, a separator, and a second electrode; a first current collector plate connected to the first electrode through a first bonding portion to be electrically connected thereto; a terminal passing through an upper portion of the case and connected to the first current collector plate through a second bonding portion to be electrically connected thereto; a cap plate coupled to the opening; and a second current collector plate positioned between the electrode assembly and the cap plate and connected to the second electrode through a third bonding portion to be electrically connected thereto, wherein at least one of the first bonding portion, the second bonding portion, and the third bonding portion has an interface formed in a wavy shape.

Description

secondary battery

[0001] The present disclosure relates to a secondary battery in which junction is performed through electromagnetic pulses.

[0002]

[0003] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries capable of both charging and discharging. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motor drive systems and power storage batteries for hybrid and electric vehicles. Such secondary batteries include electrodes comprising a positive electrode and / or a negative electrode, an electrode assembly comprising the electrodes, a case housing the same, and electrode terminals connected to the electrode assembly.

[0004] Secondary batteries include cylindrical, pouch-type, coin-type, and prismatic secondary batteries depending on the shape of the case. For example, a cylindrical secondary battery includes a can, which is a cylindrical case; and a jelly roll-shaped electrode assembly housed in the can.

[0005] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art.

[0006]

[0007] The purpose of the present invention is to provide a secondary battery in which junction is performed through electromagnetic pulses.

[0008] The purpose of the present invention is to provide a secondary battery that does not require a rust prevention and / or plating process.

[0009] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below.

[0010]

[0011] 1. A secondary battery according to an embodiment of the present invention for solving the above technical problem comprises: a case having an opening formed at the bottom; an electrode assembly housed in the case and comprising a first electrode, a separator, and a second electrode; a first current collector plate electrically connected to the first electrode through a first junction; a terminal penetrating the upper part of the case and electrically connected to the first current collector plate through a second junction; a cap plate coupled to the opening; and a second current collector plate located between the electrode assembly and the cap plate and electrically connected to the second electrode through a third junction; wherein at least one of the first junction, the second junction, and the third junction has an interface formed in a wave shape.

[0012] 2. In the above 1 embodiment, the wave shape can be formed by applying an electromagnetic pulse.

[0013] 3. In the above 1 or 2 embodiments, the wave shape may be a shape in which concave and convex parts are repeated.

[0014] 4. In the above 1 to 3 embodiments, the width of the concave or convex portion may be about 25 to 55 μm.

[0015] 5. In the above 1 to 4 embodiments, the height formed between the concave portion and the convex portion may be about 5 to 20 μm.

[0016] 6. In the above embodiments 1 to 5, the first electrode comprises: a first retaining portion having a first active material layer formed on a first substrate; and a first non-retaining portion having no first active material layer formed on the first substrate.

[0017] The above first non-removable portion may be bent so that at least a portion extends to the upper part of the electrode assembly.

[0018] 7. In the above 1 to 6 embodiments, the first joint may form the wave-shaped interface while joining the bent first unworn portion and the first current collector plate.

[0019] 8. In the above 1 to 7 embodiments, the second joint may form the wave-shaped interface while joining the lower part of the terminal and the upper part of the first current collector plate.

[0020] 9. In the above embodiments 1 to 8, the second electrode comprises: a second retaining portion having a second active material layer formed on a second substrate; and a second non-retaining portion having no second active material layer formed on the second substrate.

[0021] The above second non-removable portion may extend at least a portion to the lower part of the electrode assembly.

[0022] 10. In the above 1 to 9 embodiments, the third joint may form the wave-shaped interface while joining the bent second uncoated portion and the second current collector plate.

[0023] 11. In the above 1 to 10 embodiments, the cap plate can be joined to the case through a fourth joint that forms the wave shape at the interface with the case.

[0024] 12. In the above 1 to 11 embodiments, the fourth joint may be formed between the inner surface of the case and the outer surface of the cap plate.

[0025] 13. In the above 1 to 12 embodiments, the case is formed by folding the lower part inward, and

[0026] The above fourth joint can be formed by joining the bent lower portion and the cap plate.

[0027] 14. In the above 1 to 13 embodiments, the case is formed by folding the lower part toward the outside, and

[0028] The above fourth joint can be formed by joining the bent lower portion and the cap plate.

[0029] 15. In the above 1 to 14 embodiments, the fourth joint may be formed by joining the lower part of the case and the cap plate.

[0030] 16. In the above 1 to 15 embodiments, at least one of the first joint, the second joint, and the third joint may have an upper bead of about 0.05 mm or less.

[0031] 17. In the above 1 to 16 embodiments, at least one of the first joint, the second joint, and the third joint may have an internal bead of about 0.05 mm or less.

[0032]

[0033] According to the present invention, foreign matter in the welded area can be improved.

[0034] According to the present invention, a welding method having excellent welding strength can be provided.

[0035] According to the present invention, a welding method can be provided in which plastic deformation does not occur in the welded part.

[0036] According to the present invention, a secondary battery that does not require a surface plating process can be provided.

[0037] According to the present invention, a secondary battery with high upper space efficiency can be provided.

[0038] According to the present invention, an environmentally friendly secondary battery can be provided.

[0039] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0040]

[0041] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0042] FIG. 1 is a perspective view schematically showing a secondary battery according to one embodiment of the present invention.

[0043] FIG. 2 is a cross-sectional view schematically showing the configuration of a secondary battery according to one embodiment of the present invention.

[0044] FIG. 3 is a schematic diagram illustrating a first joint according to an embodiment of the present invention.

[0045] FIG. 4 is a schematic diagram illustrating a second joint according to an embodiment of the present invention.

[0046] FIG. 5 is a schematic diagram illustrating a third joint according to an embodiment of the present invention.

[0047] FIG. 6 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0048] FIG. 7 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0049] FIG. 8 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0050] FIG. 9 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0051] FIG. 10 is an enlarged view of a joint according to one embodiment of the present invention.

[0052] FIG. 11 is an enlarged view of a joint according to one embodiment of the present invention.

[0053]

[0054] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0055] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0056] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0057] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0058] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0059] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0060] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0061] Furthermore, where one component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected or coupled to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "coupled" through another component.

[0062] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions such as “one or more” and “one or more” preceding a list of elements modify the entire list of elements and do not modify individual elements of the list.

[0063] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less, unless specifically stated otherwise.

[0064] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0065] The term "use" may be considered synonymous with the term "utilize." As used herein, "substantially," "about," and similar terms are used as terms of approximation rather than degree, and are intended to account for the inherent variation of measured or calculated values ​​that a person skilled in the art would recognize.

[0066] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0067] Spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used herein for ease of explanation to describe the relationship between one element or feature and another element(s) or feature(s) as illustrated in the drawings. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, an element described as "below" or "below" is understood as "above" or "upper" of another element. Thus, the term "below" may encompass both the up and down directions.

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

[0069] In exemplary embodiments of prismatic / pouch / circular batteries according to the embodiments of the present disclosure, one of the prismatic / pouch / circular batteries is selected and the selected battery is described as having a general structure, and in the case of generally applicable technology, the general structure of the prismatic / pouch / circular battery is described.

[0070]

[0071] FIG. 1 is a perspective view schematically showing a secondary battery according to one embodiment of the present invention.

[0072] FIG. 2 is a cross-sectional view schematically showing the configuration of a secondary battery according to one embodiment of the present invention.

[0073] In FIGS. 1 and 2, 100 represents a secondary battery according to one embodiment of the present invention.

[0074] Referring to FIGS. 1 and 2, the secondary battery (100) according to the present embodiment includes an electrode assembly (10) and a case (20) that houses the electrode assembly (10). Additionally, the secondary battery (100) further includes a terminal (30) that is inserted into a hole (20h) formed on one side of the case (20) and electrically connected to the electrode assembly (10), and a cap plate (60) that is coupled to an opening formed on the other side of the case (20).

[0075] For example, the secondary battery (100) comprises: a case (20) having an opening formed at the bottom; an electrode assembly (10) housed in the case (20) and including a first electrode, a separator, and a second electrode; a first current collector plate (40) electrically connected to the first electrode through a first joint; a terminal (30) penetrating the top of the case (20) and electrically connected to the first current collector plate (40) through a second joint (60); a cap plate (60) coupled to the opening; and a second current collector plate (70) located between the electrode assembly (10) and the cap plate (60) and electrically connected to the second electrode through a third joint; wherein at least one of the first joint, the second joint, and the third joint may have an interface formed in a wave shape.

[0076] However, the components of the secondary battery (100) are not limited to the components shown in FIGS. 1 and 2, and the secondary battery (100) may include only some of the components shown in FIGS. 1 and 2 and / or include additional components other than those shown in FIGS. 1 and 2.

[0077] In the following description, the secondary battery (100) is described as a cylindrical battery as a lithium-ion secondary battery. However, the present invention is not limited thereto, and the secondary battery may be a lithium polymer battery or a prismatic battery.

[0078] The electrode assembly (10) can function as a unit structure that performs charging and discharging operations of power in a secondary battery (100).

[0079] The electrode assembly (10) includes a first electrode and a second electrode. The first electrode is a positive or negative electrode. The second electrode is a negative or positive electrode and has a polarity different from that of the first electrode.

[0080] Additionally, the electrode assembly (10) may further include a separator between the first electrode and the second electrode. The electrode assembly (10) can prevent the first electrode and the second electrode from coming into contact with each other and prevent a short circuit from occurring between the first electrode and the second electrode. Accordingly, the electrode assembly (10) may be formed by stacking the first electrode, the second electrode, and the separator provided between the first electrode and the second electrode.

[0081] At this time, when the electrode assembly (10) forms a cylindrical shape, the laminated structure including the first electrode, the second electrode, and the separator can be wound to form a jelly roll. For example, the electrode assembly (10) may have a shape wound along a clockwise or counterclockwise direction around a winding axis. The cross-sectional shape of the electrode assembly (10) can be designed to be various shapes, such as elliptical or polygonal, in addition to a circular shape. Here, the winding axis may refer to a straight line penetrating the center of the electrode assembly (10).

[0082] A detailed description of each component of the electrode assembly (10) is as follows.

[0083]

[0084] positive electrode active material

[0085] As a positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound) may be used. Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0086] The above composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0087] As an example, compounds represented by any one of the following chemical formulas may be used. LiaA1-bXbO2-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaMn2-bXbO4-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaNi1-b-cCobXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNi1-b-cMnbXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNibCocL1dGeO2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); LiaNiGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaCoGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-bGbO2 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn2GbO4 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-gGgPO4(0.90≤a≤1.8, 0≤g≤0.5); Li(3-f)Fe2(PO4)3(0≤f≤2); LiaFePO4(0.90≤a≤1.8).

[0088] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L1 is Mn, Al, or a combination thereof.

[0089] For example, the above-mentioned positive electrode active material may be a high-nickel positive electrode active material in which the nickel content relative to about 100 mol% of metals excluding lithium in a lithium transition metal composite oxide is about 80 mol% or more, about 85 mol% or more, about 90 mol% or more, about 91 mol% or more, or about 94 mol% or more and about 99 mol% or less. The high-nickel positive electrode active material can achieve high capacity and can be applied to high-capacity, high-density lithium batteries.

[0090] anode

[0091] A positive electrode for a secondary battery (100) may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and may further include a binder and / or a conductive material.

[0092] For example, the above anode may further include an additive that can serve as a sacrificial anode.

[0093] The content of the above positive active material is about 90% to about 99.5% by weight with respect to about 100% by weight of the positive active material layer, and the content of the above binder and conductive material may each be about 0.5% to about 5% by weight with respect to about 100% by weight of the positive active material layer.

[0094] The above binder serves to adhere the positive active material particles well to each other and also to adhere the positive active material well to the current collector. Representative examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0095] The above conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Examples of conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube; metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0096] Al may be used as the current collector mentioned above, but is not limited thereto.

[0097] cathode active material

[0098] The negative electrode active material includes 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.

[0099] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0100] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn may be used.

[0101] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The Si-based negative electrode active material may 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 may be Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0102] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0103] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0104] The above Si-based or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material.

[0105] cathode

[0106] The negative electrode for the secondary battery (100) includes a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0107] For example, the negative electrode active material layer may contain about 90% to about 99% by weight of a negative electrode active material, about 0.5% to about 5% by weight of a binder, and about 0% to about 5% by weight of a conductive material.

[0108] The above binder serves to effectively bond the negative electrode active material particles to each other and also to effectively bond the negative electrode active material to the current collector. As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used.

[0109] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0110] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0111] When a water-based binder is used as the above-mentioned cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0112] The above dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0113] The above conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fiber, carbon nanofiber, carbon nanotube; metal-based materials in the form of metal powder or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0114] As the above-mentioned cathode current collector, a material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0115] Separator

[0116] Depending on the type of secondary battery (100), a separator may be present between the positive electrode (10) and the negative electrode (20). As such a separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used, and of course, a mixed multilayer film 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.

[0117] The above separation membrane may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0118] The porous substrate may be a polymer membrane formed from any one of the following: polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacetal; polyamide; polyimide; polycarbonate; polyetherketone; polyaryletherketone; polyetherimide; polyamideimide; polybenzimidazole; polyethersulfone; polyphenylene oxide; cyclic olefin copolymer; polyphenylene sulfide; polyethylene naphthalate; glass fiber; Teflon; and polytetrafluoroethylene, or a copolymer or mixture of two or more of these.

[0119] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0120] The above inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but is not limited thereto.

[0121] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0122] The case (20) accommodates the electrode assembly (10). The case (20) seals the accommodated electrode assembly (10) together with the electrolyte.

[0123] electrolyte

[0124] The electrolyte for the secondary battery (100) includes a non-aqueous organic solvent and a lithium salt.

[0125] The above-mentioned non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0126] The above-mentioned non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof.

[0127] The above carbonate-based solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc.

[0128] Ester-based solvents such as methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methylpropionate, ethylpropionate, decanolide, mevalonolactone, valerolactone, and caprolactone may be used.

[0129] As ether-based solvents, dibutyl ether, tetraglame, diglame, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. may be used. Additionally, as ketone-based solvents, cyclohexanone, etc. may be used. As alcohol-based solvents, ethyl alcohol, isopropyl alcohol, etc. may be used, and as aprotic solvents, nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, an aromatic ring, or an ether group); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane, 1,4-dioxolane; sulfolanes, etc. may be used.

[0130] The above-mentioned non-aqueous organic solvent can be used alone or in a mixture of two or more types.

[0131] In addition, when using a carbonate-based solvent, a mixture of cyclic carbonates and chain carbonates can be used, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio of about 1:1 to about 1:9.

[0132] The above lithium salt is a substance that dissolves in an organic solvent and acts as a source of lithium ions within the battery, enabling the basic operation of the lithium battery and facilitating the movement of lithium ions between the anode and cathode. Representative examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, and LiN(CxF 2x+1 SO2)(CyF 2y+1 It may include one or more selected from SO2)(x and y are integers from 1 to 20), lithium trifluoromethane sulfonate, lithium tetrafluoroethane sulfonate, lithium difluorobis(oxalate)phosphate (LiDFOB), and lithium bis(oxalate)borate (LiBOB).

[0133] As described above, the case (20) is sealed after housing the electrode assembly (10) and the electrolyte. For example, the case (20) can be sealed by a cap plate (60).

[0134] Specifically, the case (20) forms the general appearance of the secondary battery (100). The case (20) includes an upper surface forming a cylindrical upper section and a side surface connected to the outer surface of the upper surface and extending vertically from the upper surface to form a side surface.

[0135] A hole (20h) may be formed on the upper surface of the case (20). The hole (20h) is formed by penetrating the upper surface of the case (20). The hole (20h) may be located at the center of the upper surface of the case (20). The hole (20h) may be formed, for example, at a position perpendicular to the winding core of the electrode assembly (10) and the ground. The shape of the hole (20h) may correspond to the shape of the terminal (30). For example, if the cross-section of the terminal (30) is circular, the cross-section of the hole (20h) may be formed in a circular shape. In this case, the diameter of the cross-section of the hole (20h) is larger than the diameter of the cross-section of the terminal (30).

[0136] At this time, the case (20) may have an open cylindrical lower section. The case (20) can seal the interior by closing the opening with a cap plate (60). Accordingly, the case (20) can prevent the electrolyte from leaking out and protect the electrode assembly (10).

[0137] Meanwhile, the case (20) can be manufactured from, for example, steel, stainless steel, aluminum, aluminum alloy, a combination thereof, or an equivalent thereof.

[0138] The cap plate (60) covers the opening of the case (20) and seals the case (20).

[0139] At this time, the secondary battery (100) may further include a gasket (80) to ensure that the case (20) is more securely sealed. The gasket (80) is formed, for example, in a ring shape. The gasket (80) may be positioned between the cap plate (60) and the inner surface of the case (20) while wrapping around the outer surface of the cap plate (60). Through this, the gasket (80) can prevent the electrolyte inside the secondary battery (100) from leaking out or causing safety issues.

[0140] At this time, the case (20) may form a beading portion (21) to fix the position of the cap plate (60) relative to the opening of the case (20). For example, the beading portion (21) is formed on the lower side of the case (20). The beading portion (21) is formed by the case (20) being concave from the outside to the inside. The beading portion (21) prevents the cap plate (60) from moving further into the case (20) from the opening of the case (20) through this concave portion. At this time, the case (20) may further form a crimping portion (22) to fix the position of the cap plate (60) relative to the opening of the case (20). The crimping portion (22) may be formed by the end of the opening of the case (20) being rolled toward the inside of the case (20). For example, the crimping portion (22) can be formed by bending toward the case (20) after the cap plate (60) is provided in the opening of the case (20). In this way, the cap plate (60) can cover the opening of the case (20).

[0141] At this time, the cap plate (60) can simultaneously perform the role of a vent. For example, the cap plate (60) may include a groove (61). The groove (61) may be damaged if the pressure inside the case (20) increases or the temperature rises. As the groove (61) is damaged, it can release gas generated inside the case (20) to the outside.

[0142] Meanwhile, the case (20) is electrically connected to the electrode assembly (10) housed inside the case (20). For example, the case (20) is electrically connected to the second electrode. The second electrode may be, for example, a negative electrode.

[0143] The secondary battery (100) may further include a second current collector plate (70) located at the bottom of the electrode assembly (10) to electrically connect the case (20) and the second electrode. For example, the second current collector plate (70) may be located between the bottom of the electrode assembly (10) and the top of the cap plate (60). At this time, the second current collector plate (70) and the cap plate (60) may be insulated from each other by a gasket (80). The second current collector plate (70) is, for example, a negative electrode current collector plate. The second current collector plate (70) is connected to the second electrode. For example, the second current collector plate (70) is connected to the tab of the second electrode. In addition, the second current collector plate (70) is connected to the case (20). Through this, the case (20) is electrically connected to the second electrode and may have the same polarity as the second electrode. That is, for example, the case (20) can have negative polarity.

[0144] The terminal (30) is inserted into a hole (20h) formed on the upper surface of the case (20). The terminal (30) is inserted into the hole (20h) and electrically connected to an electrode assembly (10) housed inside the case (20). For example, the terminal (30) is electrically connected to a first electrode. The first electrode may be, for example, a positive electrode.

[0145] The secondary battery (100) may further include a first current collector plate (40) located on the upper part of the electrode assembly (10) to electrically connect the terminal (30) and the first electrode. The first current collector plate (40) is, for example, a positive current collector plate. The first current collector plate (40) is connected to the first electrode. For example, the first current collector plate (40) is connected to the tab of the first electrode. In addition, the first current collector plate (40) is connected to the terminal (30). Through this, the terminal (30) is electrically connected to the first electrode and can have the same polarity as the first electrode. That is, for example, the terminal (30) can have positive polarity.

[0146] At this time, the terminal (30) may include a conductive material to be electrically connected to the first electrode. For example, the terminal (30) includes a metal. For example, the terminal (30) includes aluminum (Al).

[0147] Meanwhile, the secondary battery (100) may further include an insulating layer (90). The insulating layer (90) may be provided on the first current collector plate (40). The insulating layer (90) prevents the first current collector plate (40) and the case (20) from being electrically connected.

[0148] Through such a configuration, the secondary battery (100) according to one embodiment of the present invention can provide a battery with improved capacity by eliminating the upper beading portion. In addition, the secondary battery (100) can solve safety or financial problems that occur when the secondary battery (100) explodes upward by positioning the cap plate (60) at the bottom.

[0149]

[0150] A secondary battery (100) according to an embodiment of the present invention has been described through FIGS. 1 and 2. At this time, the secondary battery (100) has a joint portion for fixing all or part of the components included in the secondary battery (100) to each other. The joint portion includes, for example, a welded portion formed through welding.

[0151] Conventionally, such welds were formed through laser welding or ultrasonic welding.

[0152] At this time, laser welding is a welding method in which the base material is melted and fused using a heat source focused by a laser beam. However, in this case, there is a limitation on the welding depth, and there is a problem of foreign matter being generated by the welding.

[0153] Furthermore, ultrasonic welding is a method of welding using frictional heat generated by applying ultrasonic vibrations to the base material. However, in this case, welding highly brittle materials is difficult, and there is a problem with the generation of foreign matter due to friction.

[0154] As such, conventional methods for forming welded joints all suffer from the problem of foreign matter being generated during the welding process. If foreign matter is generated by welding, a separate process must be performed to remove it. However, this complicates the manufacturing process and increases costs. Furthermore, conventional welded joints suffered from plastic deformation around the weld area during the welding process, as well as corrosion and / or rust formation. In this case, a separate anti-corrosion process is required. However, this also complicates the manufacturing process and increases costs.

[0155] Therefore, it is necessary to form the weldment using a method that ensures excellent welding strength without plastic deformation.

[0156] A welded portion (W, including, for example, W1, W2, W3, and W4 described below) according to one embodiment of the present invention proposes a method of forming the welded portion (W) by applying an electromagnetic pulse to solve the aforementioned problems. Below, the welded portion (W) formed through such an electromagnetic pulse is described.

[0157]

[0158] FIG. 3 is a schematic diagram illustrating a first joint according to an embodiment of the present invention.

[0159] FIG. 3 shows a part of a secondary battery (100) according to one embodiment of the present invention. As shown in FIG. 3, the secondary battery (100) includes an electrode assembly (10) and a first current collector plate (40).

[0160] The electrode assembly (10) includes a first electrode, a second electrode, and a separator located between the first electrode and the second electrode.

[0161] The first current collector plate (40) is connected to the first electrode through the first joint (W1). The first current collector plate (40) is electrically connected to the first electrode. At this time, the first electrode includes, for example, a positive electrode.

[0162] The first electrode comprises: a first retaining portion in which a first active material layer is formed on a first substrate; and a first non-retaining portion in which a first active material layer is not formed on the first substrate.

[0163] For example, the first substrate is formed in the shape of a thin sheet or a plate. For example, if the first electrode is an anode, the first substrate includes aluminum (Al).

[0164] For example, the first active material layer is applied to the first substrate in a slurry state. Alternatively, for example, the first active material layer is attached to the first substrate in the form of a freestanding film. In this case, for example, if the first electrode is an anode, the first active material layer comprises a compound capable of reversible intercalation and deintercalation of lithium (a re-thawed intercalation compound).

[0165] For example, the first active material layer is formed on one or both sides of the first substrate. For example, the first active material layer is formed on a part of the first substrate. The first retaining portion is an area on the first substrate where the first active material layer is formed. Additionally, the first non-retaining portion is an area on the first substrate where the first active material layer is not formed.

[0166] The first electrode can be rolled around the center as the electrode assembly (10) forms a jelly roll. At this time, at least a portion of the first unwound portion may extend outside the electrode assembly (10). For example, at least a portion of the first unwound portion may extend upward from the electrode assembly (10). For example, at least a portion of the first unwound portion may extend from the electrode assembly (10) toward the first current collector plate (40).

[0167] The first collector plate (40) can be joined through the first non-removable portion and the first joint portion (W1) extending from the electrode assembly (10).

[0168] For example, the extended first non-removable portion may be partially bent to be joined to the first collector plate (40). For example, the extended first non-removable portion may be bent through a compaction process to form an area that can be joined to the first collector plate (40).

[0169] The first joint (W1) joins the bent first non-reinforced portion and the first collector plate (40).

[0170] For example, the first joint (W1) can be formed by welding the first non-contact part and the first collector plate (40) through an electromagnetic pulse. For example, the first joint (W1) can be formed by applying an electromagnetic pulse in the direction of the arrow shown in FIG. 3. That is, the electromagnetic pulse can be applied to one side of the first collector plate (40) to join the first non-contact part and the first collector plate (40).

[0171] Accordingly, the first joint (W1) can be formed in a wave shape at the interface between the first non-removable part and the first collector plate (40).

[0172] Generally, when a joint (W) is formed through a laser and / or ultrasonic process, a separate plating process is required to prevent foreign matter from occurring or rust from forming at the joint. However, a secondary battery (100) according to one embodiment of the present invention can solve this problem by welding the joint (e.g., the first joint (W1)) through electromagnetic pulses as described in FIG. 3. For example, the secondary battery (100) can simultaneously improve process efficiency and reduce costs by improving foreign matter through the application of an eco-friendly process and / or by eliminating the surface plating process.

[0173] Meanwhile, for example, the first junction (W1) may be formed in a cross shape based on the center of the first collector plate (40). As shown in FIG. 3, for example, each of the cross shapes of the first junction (W1) may be formed in the form of multiple lines. However, unlike as shown in FIG. 3, for example, each of the cross shapes of the first junction (W1) may be formed in the form of a single line. Also, unlike as shown in FIG. 3, the first junction (W1) may be formed in various shapes, such as circular, spiral, or asymmetrical structures. That is, as long as the first junction (W1) is formed by an electromagnetic pulse, its shape and number are not limited.

[0174]

[0175] FIG. 4 is a schematic diagram illustrating a second joint according to an embodiment of the present invention.

[0176] FIG. 4 shows a part of a secondary battery (100) according to one embodiment of the present invention. As shown in FIG. 4, the secondary battery (100) includes a case (20) and a terminal (30).

[0177] The terminal (30) penetrates the upper part of the case (20) and is electrically connected to the first collector plate (40) through the second joint (W2).

[0178] For example, as described in FIG. 2, the terminal (30) is formed by inserting its center into a hole (20h) formed in the case (20). At this time, the center of the terminal (30) may form a groove as shown in FIG. 2. This groove provides a space where the terminal (30) and the first current collector plate (40) can be joined.

[0179] The center of the terminal (30) inserted into the hole (20h) can come into contact with the upper surface of the first collector plate (40). The center of the terminal (30) inserted into the hole (20h) can be joined to the upper surface of the first collector plate (40) through the second joint (W2).

[0180] The second joint (W2) joins the terminal (30) and the first collector plate (40).

[0181] For example, the second joint (W2) can be formed by welding the terminal (30) and the first collector plate (40) through an electromagnetic pulse. For example, the second joint (W2) can be formed by applying an electromagnetic pulse in the direction of the arrow shown in FIG. 4. That is, the electromagnetic pulse can be applied to the center of the terminal (30) to join the terminal (30) and the first collector plate (40).

[0182] Accordingly, the second joint (W2) can be formed in a wave shape at the interface where the lower part of the terminal (30) and the upper part of the first collector plate (40) come into contact.

[0183] Generally, when a joint (W) is formed through a laser and / or ultrasonic process, a separate plating process is required to prevent foreign matter from occurring or rust from forming at the joint. However, a secondary battery (100) according to one embodiment of the present invention can solve this problem by welding the joint (e.g., the first joint (W2)) through electromagnetic pulses, as described in FIGS. 3 and 4. For example, the secondary battery (100) can simultaneously improve process efficiency and reduce costs by improving foreign matter through the application of an eco-friendly process and / or by eliminating the surface plating process.

[0184]

[0185] FIG. 5 is a schematic diagram illustrating a third joint according to an embodiment of the present invention.

[0186] FIG. 5 shows a part of a secondary battery (100) according to one embodiment of the present invention. As shown in FIG. 5, the secondary battery (100) includes an electrode assembly (10) and a second current collector plate (70).

[0187] The electrode assembly (10) includes a first electrode, a second electrode, and a separator located between the first electrode and the second electrode.

[0188] The second current collector plate (70) can be electrically connected to the second electrode through the third junction (W3). At this time, the second electrode includes, for example, a negative electrode.

[0189] The second electrode comprises: a second retaining portion in which a second active material layer is formed on a second substrate; and a second non-retaining portion in which a second active material layer is not formed on the second substrate.

[0190] For example, the second substrate is formed in the shape of a thin sheet or a plate. For example, if the second electrode is a cathode, the second substrate contains copper (Cu).

[0191] For example, the second active material layer is applied to the second substrate in a slurry state. Or, for example, the second active material layer is attached to the second substrate in the form of a freestanding film. In this case, for example, if the second electrode is a negative electrode, the second active material layer comprises 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.

[0192] For example, the second active material layer is formed on one or both sides of the second substrate. For example, the second active material layer is formed on a part of the second substrate. The second retaining portion is an area on the second substrate where the second active material layer is formed. Additionally, the second non-retaining portion is an area on the second substrate where the second active material layer is not formed.

[0193] The second electrode can be rolled around the center as the electrode assembly (10) forms a jelly roll. At this time, at least a portion of the second unwound portion may extend outside the electrode assembly (10). For example, at least a portion of the second unwound portion may extend downward from the electrode assembly (10). For example, at least a portion of the second unwound portion may extend in the opposite direction to at least a portion of the first unwound portion. For example, at least a portion of the second unwound portion may extend from the electrode assembly (10) toward the second current collector plate (70).

[0194] The second collector plate (70) can be joined through a second non-removable portion and a third joint portion (W3) extending from the electrode assembly (10).

[0195] For example, the extended second non-removable portion may be partially bent to be joined to the second collector plate (70). For example, the extended second non-removable portion may be bent through a compaction process to form an area that can be joined to the second collector plate (40).

[0196] The third joint (W3) joins the bent second non-reinforced portion and the second collector plate (70).

[0197] For example, the third joint (W3) can be formed by welding the second non-contact part and the second collector plate (70) through an electromagnetic pulse. For example, the electromagnetic pulse can be applied toward one side of the second collector plate (70) to join the second non-contact part and the second collector plate (70).

[0198] Accordingly, the third joint (W3) can be formed in a wave shape at the interface between the second non-removable part and the second collector plate (70).

[0199] Generally, when a joint (W) is formed through a laser and / or ultrasonic process, a separate plating process is required to prevent foreign matter from occurring or rust from forming at the joint. However, a secondary battery (100) according to one embodiment of the present invention can solve this problem by welding the joint (e.g., the third joint (W3)) through electromagnetic pulses as described in FIGS. 3 to 5. For example, the secondary battery (100) can simultaneously improve process efficiency and reduce costs by improving foreign matter through the application of an eco-friendly process and / or by eliminating the surface plating process.

[0200]

[0201] FIG. 6 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0202] FIG. 7 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0203] FIG. 8 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0204] FIG. 9 is a schematic diagram illustrating a fourth joint according to an embodiment of the present invention.

[0205] FIGS. 6 to 9 show a part of a secondary battery (100) according to one embodiment of the present invention. As shown in FIGS. 6 to 9, the secondary battery (100) includes a case (20) and a cap plate (60).

[0206] For example, the cap plate (60) is joined to the case (20) through a fourth joint (W4) that forms a wave-shaped interface at the contact surface with the case (20).

[0207] The fourth junction (W4) can be formed by applying an electromagnetic pulse.

[0208] For example, as illustrated in FIG. 6, a fourth joint (W4) is formed between the inner surface of the case (20) and the outer surface of the cap plate (60). For example, the inner surface of one side of the case (20) comes into contact with the outer surface of the cap plate (60). At this time, the one side of the case (20) is the side where the opening is formed. The inner surface of one side of the case (20) and the outer surface of the cap plate (60) come into contact to form an interface. The fourth joint (W4) is formed on at least a part of the interface.

[0209] Alternatively, for example, as illustrated in FIG. 7, the case (20) is formed by bending the lower portion outward, and the fourth joint (W4) is formed by joining the bent lower portion and the cap plate (60). For example, one side of the case (20) is bent outward toward the outside of the case (20). Accordingly, the inner surface of the case (20) faces the lower portion of the case (20) as the case (20) is bent. For example, in the bent area, the inner surface of the case (20) provides a flat area that can be joined with the cap plate (60). The bent area of ​​the case (20) and the edge of one side of the cap plate (60) come into contact to form an interface. The fourth joint (W4) is formed on at least a portion of the interface. Through this, the secondary battery (100) provides a method for the case (20) and the cap plate (60) to be stably joined. In addition, the secondary battery (100) provides a method to improve battery capacity.

[0210] Alternatively, for example, as illustrated in FIG. 8, the case (20) is formed by bending the lower portion inward, and the fourth joint (W4) is formed by joining the bent lower portion and the cap plate (60). For example, one side of the case (20) is bent toward the interior of the case (20). Accordingly, the outer surface of the case (20) faces toward the lower portion of the case (20) as the case (20) is bent. For example, in the bent area, the outer surface of the case (20) provides a flat area that can be joined with the cap plate (60). The bent area of ​​the case (20) and the edge of one side of the cap plate (60) come into contact to form an interface. The fourth joint (W4) is formed on at least a portion of the interface. Through this, the secondary battery (100) provides a method for the case (20) and the cap plate (60) to be stably joined. In addition, the secondary battery (100) provides a method to improve battery capacity.

[0211] Alternatively, for example, as illustrated in FIG. 9, the fourth joint (W4) is formed by joining the lower part of the case (20) and the cap plate (60). For example, one end of the case (20) (for example, the lower part of the case (20)) comes into contact with one surface of the cap plate (60). At this time, one side of the case (20) is the side where the opening is formed. The end of one side of the case (60) and one surface of the cap plate (60) come into contact to form an interface. The fourth joint (W4) is formed on at least a part of the interface. Through this, the secondary battery (100) provides a method to maximize battery capacity.

[0212] As explained through FIGS. 6 to 9, the fourth joint (W4) joins the case (20) and the cap plate (60).

[0213] For example, the fourth joint (W4) can be formed by welding the case (20) and the cap plate (60) through an electromagnetic pulse. For example, the electromagnetic pulse can be applied toward the outer surface of the case (20) to join the case (20) and the cap plate (60). Or, for example, the electromagnetic pulse can be applied toward the edge of one side of the cap plate (60) to join the case (20) and the cap plate (60).

[0214] In this way, the fourth joint (W4) can be formed in a wave shape at the interface between the case (20) and the cap plate (60).

[0215] Generally, when a joint (W) is formed through a laser and / or ultrasonic process, a separate plating process is required to prevent foreign matter from occurring or rust from forming at the joint. However, a secondary battery (100) according to one embodiment of the present invention can solve this problem by welding the joint (e.g., the fourth joint (W4)) through electromagnetic pulses, as described in FIGS. 3 to 9. For example, the secondary battery (100) can simultaneously improve process efficiency and reduce costs by improving foreign matter through the application of an eco-friendly process and / or by eliminating the surface plating process.

[0216]

[0217] FIG. 10 is an enlarged view of a joint according to one embodiment of the present invention.

[0218] FIG. 11 is an enlarged view of a joint according to one embodiment of the present invention.

[0219] In FIGS. 10 and 11, a joint portion according to an embodiment of the present invention described in FIGS. 3 to 9 (e.g., including at least one of W1, W2, W3, and W4; hereinafter referred to as W) is illustrated in an enlarged manner. FIGS. 10 and 11 illustrate an example in which the joint portion (W) is formed at the interface between Al and Cu, but the joint portion (W) according to an embodiment of the present invention is not limited thereto.

[0220] The junction (W) is formed by applying an electromagnetic pulse. For example, the following steps may be performed to form the junction (W).

[0221] First, an electromagnetic coil is positioned at the location where the junction is to be formed. The electromagnetic coil applies an electromagnetic force generated from the coil to the location where the junction is to be formed. The junction, upon receiving the electromagnetic force, joins the interface through repulsive force. At this time, the electromagnetic force includes concentrated electrical energy.

[0222] Such electromagnetic pulse application can be performed at room temperature. In addition, the junction can be formed within a short time depending on the application of the electromagnetic pulse.

[0223] For example, the junction (W) is formed by applying an electromagnetic force toward the location where the junction (W) is scheduled to be formed (hereinafter referred to as the "target location").

[0224] For example, the electromagnetic force may be applied toward the target location at a speed of about 1.0 m / min to about 2.0 m / min. Or, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.0 m / min to about 1.8 m / min. Or, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.0 m / min to about 1.6 m / min. Or, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.2 m / min to about 2.0 m / min. Or, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.2 m / min to about 1.8 m / min. Or, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.2 m / min to 1.6 m / min. Alternatively, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.4 m / min to about 2.0 m / min. Alternatively, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.4 m / min to about 1.8 m / min. Alternatively, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.4 m / min to about 1.6 m / min. Alternatively, for example, the electromagnetic force may be applied toward the target location at a speed of about 1.5 m / min.

[0225] When the electromagnetic force is applied toward the target location at a speed of less than approximately 1.0 m / min, there is a problem that the bonding strength of the junction (W) is reduced. In addition, when the electromagnetic force is applied toward the target location at a speed exceeding approximately 2.0 m / min, the electromagnetic force may penetrate the junction (W) and damage the electrode assembly (10), etc. Therefore, it is preferable that the electromagnetic force be applied toward the target location at a speed of approximately 1.0 m / min to 2.0 m / min.

[0226] For example, the electromagnetic force may be applied toward the target location with a current of about 20 mA to about 25 mA. Or, for example, the electromagnetic force may be applied toward the target location with a current of about 21 mA to about 25 mA. Or, for example, the electromagnetic force may be applied toward the target location with a current of about 22 mA to about 25 mA. Or, for example, the electromagnetic force may be applied toward the target location with a current of about 23 mA to about 25 mA. Or, for example, the electromagnetic force may be applied toward the target location with a current of about 23 mA to about 24 mA. Or, for example, the electromagnetic force may be applied toward the target location with a current of about 23 mA.

[0227] When an electromagnetic force is applied to a target location with a current of less than about 20 mA, there is a problem that the bonding strength of the junction (W) is reduced. In addition, when an electromagnetic force is applied toward a target location with a current of more than about 25 mA, the target location may be damaged by the electromagnetic force. Therefore, it is preferable that the electromagnetic force be applied to a target location with a current of about 20 mA to about 25 mA.

[0228] For example, the electromagnetic force may be applied in a vacuum for a period of about 2.5 seconds to about 3.0 seconds. Or, for example, the electromagnetic force may be applied in a vacuum for a period of about 2.5 seconds to about 2.9 seconds. Or, for example, the electromagnetic force may be applied in a vacuum for a period of about 2.5 seconds to about 2.8 seconds. Or, for example, the electromagnetic force may be applied in a vacuum for a period of about 2.6 seconds to 3.0 seconds. Or, for example, the electromagnetic force may be applied in a vacuum for a period of about 2.6 seconds to about 2.9 seconds. Or, for example, the electromagnetic force may be applied in a vacuum for a period of about 2.6 seconds to about 2.8 seconds. Or, for example, the electromagnetic force may be applied in a vacuum for a period of about 2.7 seconds to about 3.0 seconds. Or, for example, the electromagnetic force may be applied in a vacuum for a period of about 2.7 seconds to about 2.9 seconds. Alternatively, for example, the electromagnetic force may be applied in a vacuum for a time of about 2.7 seconds to about 2.8 seconds. Alternatively, for example, the electromagnetic force may be applied in a vacuum for a time of about 2.8 seconds.

[0229] If the electromagnetic force is applied to the target location for a period of less than approximately 2.5 seconds, there is a problem that the bonding strength of the junction (W) is reduced. In addition, if the electromagnetic force is applied toward the target location for a period of more than approximately 3.0 seconds, the target location may be damaged by the electromagnetic force. Therefore, it is preferable that the electromagnetic force be applied to the target location for a period of approximately 2.5 seconds to approximately 3.0 seconds.

[0230] At this time, the vacuum standard includes a state of about 0.6 Pa to about 7 Pa.

[0231] Through this, the junction according to one embodiment of the present invention can contribute to improving the quality of the secondary battery (100).

[0232] A joint (W) according to one embodiment of the present invention welds through repulsive force by electric energy. Accordingly, the materials being joined in the joint (W) do not melt, and / or welding marks or corrosion do not occur due to fusion interface welding. Furthermore, the joint (W) is applicable even when the materials being joined are dissimilar and / or homogeneous materials.

[0233] A junction (W) according to one embodiment of the present invention can be formed in the following shape as an electromagnetic pulse is applied.

[0234] For example, the joint (W) forms a wave shape at the interface (e.g., including the wave shape described in FIGS. 3 to 9). The wave shape is as illustrated in FIGS. 10 to 11, for example.

[0235] The wave shape includes, for example, a shape in which concave and convex parts are repeated. In this case, the width and height of the concave and convex parts may not be constant. FIG. 10 shows the depth (h) formed between the concave and convex parts, and FIG. 11 shows the width (d) of each of the concave or convex parts.

[0236] The depth (h) formed between the concave and convex portions represents the height difference between the valley of the concave portion and the crest of the convex portion. In this case, the concave portion and the convex portions represent the concave portion and the convex portion located adjacent to each other.

[0237] The depth (h) is formed, for example, to about 5 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 6 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 7 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 8 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 9 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 10 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 11 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 12 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 13 µm to about 20 µm. Or, the depth (h) is formed, for example, to about 14 µm to about 20 µm. Alternatively, the depth (h) is formed to be, for example, about 15 µm to about 20 µm.

[0238] The width (d) of the concave or convex portion represents the width of the concave portion and the convex portion, respectively.

[0239] The width (d) includes, for example, about 25 µm to about 55 µm. Or the width (d) includes, for example, about 25 µm to about 55 µm. Or the width (d) includes, for example, about 30 µm to about 55 µm. Or the width (d) includes, for example, about 25 µm to about 50 µm. Or the width (d) includes, for example, about 30 µm to about 50 µm.

[0240] As such, since melting does not occur between the materials being welded in the joint (W) according to one embodiment of the present invention, the welding depth formed by the joint (W) is formed to be shallow. Accordingly, the joint (W) can be applied even when each material is formed thinly.

[0241] Additionally, for example, the joint (W) may form an upper weld bead with a height of about 0.05 mm or less (e.g., 0.01, 0.02, 0.03, 0.04, or 0.05) or may not form an upper weld bead. When the joint is formed by a laser or ultrasound as in the prior art, an upper weld bead is formed. These upper weld beads are formed with a size of at least about 0.04 mm, and generally with a size of about 0.10 mm or more. Accordingly, there was a problem in that the energy density of the secondary battery was reduced and / or the space efficiency of the secondary battery was reduced due to the upper weld bead.

[0242] However, the joint (W) according to the present invention may not form an upper weld bead, and / or may form an upper weld bead of a minimum size. Accordingly, a secondary battery (100) according to one embodiment of the present invention can improve both energy density and / or space efficiency.

[0243] Additionally, for example, the joint (W) may form an internal weld bead with a height of about 0.05 mm or less (e.g., 0.01, 0.02, 0.03, 0.04, or 0.05) or may not form an internal weld bead. When the joint is formed by a laser or ultrasound as in the prior art, an internal weld bead is formed. These internal weld beads are formed with a size greater than at least about 0.05 mm, and generally with a size greater than about 0.20 mm. Consequently, there was a problem of reduced energy density of the secondary battery and / or leakage occurring at the target location due to the internal weld bead.

[0244] However, the joint (W) according to the present invention may not form an internal weld bead, and / or may form an internal weld bead of a minimum size. Accordingly, the secondary battery (100) according to one embodiment of the present invention can improve internal and external space efficiency and secure both strength at the target location and joint strength.

[0245] Meanwhile, it is obvious that the joint (W) can form a weld bead in which the height of the upper weld bead is about 0.05 mm or less and the height of the inner weld bead is about 0.05 mm or less.

[0246] In addition, for example, the joint (W) can be configured to have a joint strength (based on sealing pressure) of approximately 18.9 kg / f or more. As such, the joint (W) according to one embodiment of the present invention has excellent welding strength.

[0247] The following shows the bonding strength of the joints according to the comparative example and the example through [Table 1].

[0248] Bonding Strength (kg / f) Tensile Test Angle: 90 degrees Tensile Test Angle: 180 degrees Comparative Example 1 29 250 Example 2 39 450

[0249] In this case, the comparative example represents a joint formed through a laser, and the example represents a joint formed through an electromagnetic pulse as a joint according to one embodiment of the present invention. In this case, the joint was formed under the following conditions.

[0250] 1) Speed: 1.5 m / min

[0251] 2) Beam current: 23mA

[0252] 3) Beam current time (vacuum reference): 2.8 sec

[0253] In addition, the comparative example and the test example were formed as specimens with an area of ​​25 mm X 10 mm.

[0254] As can be seen from [Table 1], the bonding strength according to one embodiment of the present invention is 50% higher than that of the comparative example.

[0255]

[0256] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. A case in which an opening is formed at the bottom; An electrode assembly housed in the above case and comprising a first electrode, a separator, and a second electrode; A first current collector plate electrically connected to the first electrode through a first joint; A terminal that penetrates the upper part of the above case and is electrically connected to the first current collector plate through a second joint; A cap plate coupled to the above opening; and A second current collector plate positioned between the electrode assembly and the cap plate, and electrically connected to the second electrode through a third joint; comprising At least one of the first joint, the second joint, and the third joint has an interface formed in a wave shape, Secondary battery.

2. In claim 1, the wave shape is a secondary battery formed by applying an electromagnetic pulse.

3. A secondary battery according to claim 1, wherein the wave shape is a shape in which concave and convex parts are repeated.

4. A secondary battery according to claim 3, wherein the width of the concave or convex portion is about 25 to 55 μm.

5. A secondary battery according to claim 3, wherein the height formed between the concave portion and the convex portion is about 5 to about 20 µm.

6. In Paragraph 1, The first electrode comprises: a first retaining portion having a first active material layer formed on a first substrate; and a first non-retaining portion having no first active material layer formed on the first substrate. A secondary battery in which at least a portion of the first unoccupied portion is bent and extended to the upper part of the electrode assembly.

7. In Paragraph 6, A secondary battery in which the first joint forms the wave-shaped interface while joining the bent first non-reinforced portion and the first current collector plate.

8. In Paragraph 1, A secondary battery in which the second joint forms a wave-shaped interface while joining the lower part of the terminal and the upper part of the first current collector plate.

9. In Paragraph 1, The second electrode comprises: a second retaining portion having a second active material layer formed on a second substrate; and a second non-retaining portion having no second active material layer formed on the second substrate. A secondary battery in which at least a portion of the second non-removable portion extends to the lower part of the electrode assembly and is bent.

10. In Paragraph 9, A secondary battery in which the third joint forms the wave-shaped interface while joining the bent second non-reinforced portion and the second current collector plate.

11. In Paragraph 1, The above cap plate is a secondary battery that is joined to the case through a fourth joint forming the wave shape at the interface with the case.

12. In claim 11, the fourth joint is formed between the inner surface of the case and the outer surface of the cap plate, a secondary battery.

13. In Paragraph 11, The above case is formed with the lower part bent inward, and The above-mentioned fourth joint is a secondary battery formed by joining the bent lower portion and the cap plate.

14. In Paragraph 11, The above case is formed with the lower part bent outward, and The above-mentioned fourth joint is a secondary battery formed by joining the bent lower portion and the cap plate.

15. In claim 11, the fourth joint is formed by joining the lower part of the case and the cap plate, in a secondary battery.

16. A secondary battery according to claim 1, wherein at least one of the first joint, the second joint, and the third joint has an upper bead of about 0.05 mm or less.

17. The secondary battery according to claim 1, wherein at least one of the first junction, the second junction, and the third junction has an internal bead of about 0.05 mm or less.

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