Secondary battery

Abstract

The present disclosure relates to a secondary battery. The technical problem is to be solved by providing a beadingless cylindrical secondary battery that ensures sealability while reducing the number of parts and provides an injection port to the cathode side rather than the anode side. To this end, the present disclosure provides the secondary battery comprising: a cylindrical case; an electrode assembly which is accommodated in the case, and which includes a first tab protruding in a first direction and a second tab that protrudes in a second direction opposite to the first direction and is connected to the case; a current collector plate which is accommodated in the case, and which includes a current collector plate body portion connected to the first tab and a current collector plate injection portion provided in the current collector plate body portion; a cap plate for blocking the case such that the electrode assembly and the current collector plate are isolated from the outside; a rivet terminal including a rivet body portion coupled to the cap plate, and a rivet injection portion to which the current collector plate injection portion is coupled; and a sealing portion for sealing the current collector plate injection portion and the rivet injection portion.

Description

secondary battery

[0001] The present invention relates to a secondary battery.

[0002] Secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and dischargeable. Low-capacity secondary batteries are used in small, portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for motor drives and power storage in hybrid and electric vehicles. These secondary batteries include an electrode assembly comprising a positive and negative electrode, a case housing the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] 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.

[0004] The present invention provides a beadless cylindrical secondary battery that has a reduced number of parts while ensuring sealing and has a charging port provided on the positive electrode side rather than the negative electrode side.

[0005] 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.

[0006] According to one embodiment of the present invention for solving the above technical problem, a secondary battery may include a cylindrical case; an electrode assembly accommodated in the case and including a first tab protruding in a first direction and a second tab protruding in a second direction opposite to the first direction and connected to the case; a current collector plate accommodated in the case and including a current collector plate body portion connected to the first tab and a current collector plate injection portion provided in the current collector plate body portion; a cap plate closing the case so that the electrode assembly and the current collector plate are isolated from the outside; a rivet terminal including a rivet body portion coupled to the cap plate and a rivet injection portion coupled to the current collector plate injection portion; and a sealing portion sealing the current collector plate injection portion and the rivet injection portion.

[0007] In one or more embodiments, the collector plate injection portion may protrude in the first direction from the center of the collector plate body portion and include a collector plate injection through hole.

[0008] In one or more embodiments, the rivet body portion may include an upper flange portion extending outwardly horizontally from an upper side of the rivet injection portion and positioned on an upper side of the cap plate with an upper insulator interposed therebetween, and a lower flange extending outwardly horizontally from a lower side of the rivet injection portion and positioned on a lower side of the cap plate with a lower insulator interposed therebetween, and the rivet injection portion may be penetratedly connected to the cap plate with an insulating gasket interposed therebetween, and may include a rivet injection through hole to which the collector injection portion is coupled.

[0009] In one or more embodiments, the outer diameter surface of the current collector plate assembly and the inner diameter surface of the rivet assembly may be provided in close contact with each other and parallel to the first direction.

[0010] In one or more embodiments, the outer surface of the current collector plate assembly and the inner surface of the rivet assembly may be provided in close contact with each other and inclined with respect to the first direction.

[0011] In one or more embodiments, the outer diameter of the current collector plate assembly and the inner diameter of the rivet assembly may gradually decrease as they move away from the electrode assembly.

[0012] In one or more embodiments, the upper side of the collector plate assembly and the upper side of the rivet assembly can be joined to each other by laser welding.

[0013] In one or more embodiments, the sealing portion may include a sealing body portion covering the collector plate injection portion and the rivet injection portion, and a sealing protrusion portion coupled to the collector plate injection portion.

[0014] In one or more embodiments, the rivet insert may include a rivet recess into which the sealing body portion is seated.

[0015] In one or more embodiments, the perimeter of the sealing body portion may be laser welded to the rivet recess.

[0016] In one or more embodiments, the sealing ball may further be coupled to the collector plate injection part, and the sealing part may include a sealing body part covering the collector plate injection part and the rivet injection part.

[0017] In one or more embodiments, the rivet insert may include a rivet recess into which the sealing body portion is seated.

[0018] In one or more embodiments, the perimeter of the sealing body portion may be laser welded to the rivet recess.

[0019] In one or more embodiments, the case includes a bottom portion and a side wall portion extending in the first direction from a periphery of the bottom portion, and the second tab can be directly laser welded to the bottom portion.

[0020] In one or more embodiments, the bottom portion may include a peripheral portion adjacent to the side wall portion, a vent notch provided in the peripheral portion, and a recessed portion extending inwardly of the peripheral portion and closer to the electrode assembly than the peripheral portion.

[0021] According to the present invention, a beadless cylindrical secondary battery is provided, which reduces the number of components while ensuring sealing and has a filler port on the positive electrode side rather than the negative electrode side. Furthermore, according to the present invention, the structure of the positive electrode terminal is improved, thereby enhancing the welding strength of the positive electrode terminal and facilitating the detection of welding defects. Furthermore, according to the present invention, a sealing pin is bonded and welded to the positive electrode filler port, thereby improving sealing and facilitating the detection of welding defects.

[0022] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0023] 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.

[0024] FIG. 1a and FIG. 1b are a perspective view and a cross-sectional view illustrating an exemplary cylindrical secondary battery according to the present invention.

[0025] Figures 2a and 2b are enlarged cross-sectional views showing areas 2a and 2b of Figure 1b.

[0026] FIGS. 3A and 3B are an exploded cross-sectional perspective view and a combined cross-sectional perspective view illustrating an exemplary cylindrical secondary battery according to the present invention.

[0027] FIG. 4 is a cross-sectional perspective view illustrating an exemplary case in an exemplary cylindrical secondary battery according to the present invention.

[0028] Figures 5a and 5b are enlarged cross-sectional perspective views showing areas 5a and 5b of Figure 4.

[0029] FIG. 6 is a cross-sectional perspective view illustrating an exemplary cap assembly and an exemplary collector plate in an exemplary cylindrical secondary battery according to the present invention.

[0030] FIGS. 7A and 7B are enlarged cross-sectional views illustrating a positive electrode sealing structure in an exemplary cylindrical secondary battery according to the present invention.

[0031] FIG. 8 is an enlarged cross-sectional view illustrating another positive electrode sealing structure in an exemplary cylindrical secondary battery according to the present invention.

[0032] FIG. 9a and FIG. 9b are perspective views and cross-sectional views illustrating a sealing portion constituting a positive electrode sealing structure in an exemplary cylindrical secondary battery according to the present invention.

[0033] FIG. 10 is a cross-sectional view illustrating a sealing portion constituting a positive electrode sealing structure in an exemplary cylindrical secondary battery according to the present invention.

[0034] FIGS. 11A and 11B are perspective views illustrating a battery pack including an exemplary cylindrical secondary battery according to the present invention.

[0035] FIGS. 12A and 12B are perspective and side views illustrating a vehicle including an exemplary battery pack according to the present invention.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0042] 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.

[0043] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to each other, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component. Furthermore, when it is said that a part is electrically coupled to another part, this includes not only cases where they are directly connected, but also cases where they are connected with another element in between.

[0044] When reference is made throughout the specification to "A and / or B," this means A, B, or A and B, unless otherwise stated. In other words, "and / or" includes all or any combination of the listed items. When reference is made to "C through D," this means C or more and D or less, unless otherwise stated.

[0045] 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.

[0046] FIGS. 1A and 1B are perspective views and cross-sectional views illustrating an exemplary cylindrical secondary battery (100) according to the present invention. As illustrated in FIGS. 1A and 1B, the exemplary secondary battery (100) according to the present invention may include a case (110), an electrode assembly (120), a current collector plate (130), a cap plate (141), a rivet terminal (150), and a sealing portion (160).

[0047] The case (110) accommodates the electrode assembly (120) and the electrolyte, and together with the cap plate (141), can form the outer shape of the secondary battery (100). The case (110) can include a bottom portion (111) having a substantially circular shape and a cylindrical side wall portion (112) extending upward from the bottom portion (111). In one or more embodiments, the case (110) can be formed in various shapes, such as a pouch shape, in addition to a circular shape. In addition, the case (110) can include a metal, such as steel, nickel-plated steel, a steel alloy, aluminum, an aluminum alloy, a cooling sheet for deep drawing (SPCE), or a laminate film or plastic forming a pouch.

[0048] The electrode assembly (120) may include a first electrode plate (121), a second electrode plate (122), and a separator (123) between the first electrode plate (121) and the second electrode plate (122), and may be wound in a jelly-roll shape. In one or more embodiments, a hollow core (124) may be provided longitudinally at the center of the electrode assembly (120). In one or more embodiments, a center pin (optional) may be coupled to the core (124).

[0049] The first electrode plate (121) may include a first substrate (1211) and a first active material layer (1212) positioned on the first substrate (1211). A first non-conductive portion or first tab (1213) of the first substrate (1211) where the first active material layer (1212) is not positioned may extend outward (e.g., upward), and the first tab (1213) may be electrically connected to the cap plate (141).

[0050] The second electrode plate (122) may include a second substrate (1221) and a second active material layer (1222) positioned on the second substrate (1221). A second non-conductive portion or second tab (1223) of the second substrate (1221) where the second active material layer (1222) is not positioned may extend outward (e.g., downward), and the second tab (1223) may be electrically connected to the case (110). In one or more embodiments, the first tab (1213) and the second tab (1223) may extend in opposite directions.

[0051] The first electrode plate (121) can function as an anode. In this case, the first substrate (1211) can be composed of, for example, aluminum foil, and the first active material layer (1212) can include, for example, a transition metal oxide. The second electrode plate (122) can function as an anode. In this case, the second substrate (1221) can be composed of, for example, copper foil or nickel foil, and the second active material layer (1222) can include, for example, graphite and / or silicon.

[0052] The separator (123) can prevent short circuiting between the first electrode plate (121) and the second electrode plate (122) while allowing movement of lithium ions. In one or more embodiments, the separator (123) can be positioned on opposite sides of the first electrode plate (121), or on opposite sides of the second electrode plate (122).

[0053] In one or more embodiments, a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) may be used as the positive electrode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0054] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0055] As an example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li aNiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0056] 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; L 1 is Mn, Al or a combination thereof.

[0057] A positive electrode for a lithium secondary battery may include a current collector (e.g., a first substrate) and a positive electrode active material layer formed on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0058] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0059] Aluminum may be used as the current collector, but is not limited thereto.

[0060] 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.

[0061] 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 the crystalline carbon include graphite such as natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0062] As the material capable of doping and dedoping the 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-based alloy, or a combination thereof.

[0063] The above 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.

[0064] 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.

[0065] A negative electrode for a lithium secondary battery may include a current collector (e.g., a second substrate) and a negative electrode active material layer formed 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.

[0066] For example, the negative electrode active material layer may include 90 to 99 wt% of the negative electrode active material, 0.5 to 5 wt% of the binder, and 0 to 5 wt% of the conductive material.

[0067] The above binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0068] The current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0069] An electrolyte for a lithium secondary battery may include a non-aqueous organic solvent and a lithium salt.

[0070] The above non-aqueous organic solvent acts as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0071] The above 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, and may be used alone or in combination of two or more thereof.

[0072] Additionally, when using a carbonate solvent, a mixture of cyclic carbonate and chain carbonate can be used.

[0073] As described above, a lithium secondary battery may have a separator between the positive and negative electrodes. Such a separator may be a multilayer film of polyethylene, polypropylene, polyvinylidene fluoride, or two or more layers thereof.

[0074] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof, positioned on one or both sides of the porous substrate.

[0075] The above organic material may include a polyvinylidene fluoride-based antibody or a (meth)acrylic polymer.

[0076] 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.

[0077] 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.

[0078] The current collector (130) may include a current collector body (131) and a current collector liquid injection portion (132). In one or more embodiments, the current collector liquid injection portion (132) may further include a current collector liquid injection through hole (133). The current collector body (131) may have a generally round disc shape, and a plurality of first tabs (1213) extending / protruding from the electrode assembly (120) may be electrically connected to the lower surface of the current collector body (131). The current collector liquid injection portion (132) may be electrically / mechanically coupled to a rivet terminal (150). In one or more embodiments, an electrolyte may be injected through the current collector liquid injection through hole (133). Accordingly, the electrolyte can be provided directly to the core (124) of the electrode assembly (120), and then the electrolyte can be absorbed into the remaining area of ​​the electrode assembly (120). The collector plate (130) can include aluminum, an aluminum alloy, copper, a copper alloy, nickel, or a nickel alloy.

[0079] The cap plate (141) can be coupled to the upper side of the case (110) to seal the case (110). The cap plate (141) can be generally provided in a circular shape. In one or more embodiments, the periphery of the cap plate (141) can be coupled to the side wall portion (112) of the case (110) to seal the case (110). The cap plate (141) can be composed of iron, nickel-plated iron, stainless steel, aluminum, or an aluminum alloy. In one or more embodiments, the cap plate (141) and the rivet terminal (150) coupled thereto via an insulating member are collectively referred to as a cap assembly (140). In other words, the cap assembly (140) in some cases may be a concept including a cap plate and a rivet terminal.

[0080] The rivet terminal (150) may include a rivet body portion (151) and a rivet insert portion (152). In one or more embodiments, the rivet insert portion (152) may include a rivet insert through hole (153). The rivet insert portion (152) may be coupled by penetrating the cap plate (141). An insulating gasket (1521) may be interposed between the rivet insert portion (152) and the cap plate (141). The rivet terminal (150) may be electrically / mechanically coupled to the current collector (130). In one or more embodiments, the current collector insert portion (132) may be fitted into the rivet insert portion (152). In other words, the current collector insert portion (132) may be coupled to the rivet insert through hole (153). The rivet terminal (150) may include aluminum, an aluminum alloy, copper, a copper alloy, nickel, or a nickel alloy.

[0081] The sealing portion (160) can be coupled to the rivet terminal (150). The sealing portion (160) can be provided in a generally circular shape. The sealing portion (160) can block the current collector plate injection portion (132) and the rivet injection portion (152). In other words, the sealing portion (160) can block the current collector plate injection penetration hole (133). The sealing portion (160) can include aluminum, an aluminum alloy, copper, a copper alloy, nickel, or a nickel alloy.

[0082] Figures 2a and 2b are enlarged cross-sectional views showing areas 2a and 2b of Figure 1b.

[0083] As illustrated in FIG. 2A, the collector plate (130) may include a collector plate body portion (131) that is connected (e.g., laser welded) to a first tab (1213) and a collector plate injection portion (132) that is provided to extend upward from the collector plate body portion (131), and the collector plate injection portion (132) may include a collector plate injection through hole (133). In one or more embodiments, the first tab (1213) may be provided with a compaction process in one direction (e.g., toward the core or away from the core), so that the first tab (1213) may be connected to the collector plate body portion (131) while lying in one direction. In addition, the rivet terminal (150) may include a rivet body portion (151) coupled to the cap plate (141) and a rivet injection portion (152) coupled to the collector plate injection portion (132), and the rivet injection portion (152) may include a rivet injection through hole (153). In addition, the sealing portion (160) may be coupled (e.g., laser welded) to the collector plate injection portion (132) and the rivet injection portion (152).

[0084] In one or more embodiments, the collector plate injection part (132) may protrude in a first direction from the center of the collector plate body part (131) and include a collector plate injection through hole (133) provided at the inner center.

[0085] In one or more embodiments, the rivet body portion (151) may include an upper flange portion (1511) that is bent and extended in an outward horizontal direction from the upper side of the rivet injection portion (152) and positioned on the upper side of the cap plate (141). In one or more embodiments, an upper insulator (1512) may be interposed between the upper flange portion (1511) and the cap plate (141).

[0086] In one or more embodiments, the rivet body portion (151) may also include a lower flange portion (1513) that is bent and extended outwardly horizontally from the lower side of the rivet insert portion (152) and positioned on the lower side of the cap plate (141). In one or more embodiments, a lower insulator (1514) may be interposed between the lower flange portion (1513) and the cap plate (141).

[0087] In one or more embodiments, the rivet insert (152) may be penetrated and connected to the cap plate (141) via an insulating gasket (1521). As described above, the collector insert (132) may be connected to the rivet insert through hole (153). In one or more embodiments, the upper insulator (1512), the insulating gasket (1521), and the lower insulator (1514) may be formed integrally, or may be formed separately and integrated.

[0088] As illustrated in FIG. 2B, the bottom portion (111) of the case (110) may be connected (e.g., laser welded) to the second tab (1223). In one or more embodiments, the second tab (1223) may be provided with a tamping process in one direction (e.g., toward the core or away from the core), such that the second tab (1223) may be connected to the bottom portion (111) of the case (110) while lying in one direction.

[0089] FIG. 3a and FIG. 3b are an exploded cross-sectional perspective view and a combined cross-sectional perspective view illustrating an exemplary cylindrical secondary battery (100) according to the present invention.

[0090] As illustrated in FIG. 3a, a cylindrical electrode assembly (120) can be coupled to a cylindrical case (110), then a current collector (130) can be positioned on the electrode assembly (120), and finally, a cap assembly (140) including a cap plate (141) and a rivet terminal (150) can be coupled to the case (110).

[0091] As illustrated in FIG. 3B, the current collector body (132) and the rivet body (152) may be laser welded and joined to each other. In addition, the periphery of the cap plate (141) and the side wall portion (112) of the case (110) may be laser welded to each other. In addition, the second tab (1223) of the electrode assembly (120) may be laser welded to the bottom portion (111) of the case (110). In one or more embodiments, the first tab (1213) of the electrode assembly (120) may be laser welded first to the current collector body portion (131). The lightning bolt symbol in the drawing indicates laser welding.

[0092] FIG. 4 is a cross-sectional perspective view illustrating an exemplary case (110) in an exemplary cylindrical secondary battery (100) according to the present invention, and FIGS. 5a and 5b are enlarged cross-sectional perspective views illustrating areas 5a and 5b of FIG. 4.

[0093] As illustrated in FIGS. 4, 5A, and 5B, the case (110) may include a bottom portion (111) and a side wall portion (112) extending in a first direction from a periphery of the bottom portion (111). In one or more embodiments, the bottom portion (111) may include a periphery portion (1111) adjacent to the side wall portion (112), a vent notch (1112) provided in the periphery portion (1111), and a recessed portion (1113) extending inwardly of the periphery portion (1111) and closer to the electrode assembly (120) than the periphery portion (1111). In one or more embodiments, the vent notch (1112) may be provided on an upper side of the periphery portion (1111). In this way, when the internal pressure of the secondary battery (100) increases, the recessed portion (1113) is first deformed in a direction away from the electrode assembly (120) (e.g., in the second direction), and when the internal pressure of the battery is greater than the reference pressure, the vent notch (1112) is broken, allowing the internal gas of the battery to be discharged to the outside. In one or more embodiments, the second tab (1223) of the electrode assembly (120) may be directly laser welded to the recessed portion (1113) among the bottom portions (111).

[0094] In one or more embodiments, a groove (1121) may be further provided on the upper side of the side wall portion (112). In one or more embodiments, the groove (1121) may be provided on the inner side of the side wall portion (112). Accordingly, the cap plate (141) may be coupled to the groove (1121) of the side wall portion (112). Of course, the boundary area of ​​the cap plate (141) and the side wall portion (112) may be coupled to each other by laser welding.

[0095] FIG. 6 is a cross-sectional perspective view illustrating an exemplary cap assembly (140) and an exemplary current collector (130) in an exemplary cylindrical secondary battery (100) according to the present invention, and FIGS. 7a and 7b are enlarged cross-sectional views illustrating a positive electrode sealing structure in an exemplary cylindrical secondary battery (100) according to the present invention.

[0096] As illustrated in FIGS. 6 and 7A, the collector plate insert (132) can be inserted into the rivet insert (152). In one or more embodiments, the upper end of the collector plate insert (132) can be substantially flush with the upper end of the rivet insert (152). In one or more embodiments, the upper end of the collector plate insert (132) can be substantially flush with the upper end of the rivet recess (154) of the rivet insert (152). In one or more embodiments, the outer surface of the collector plate insert (132) and the inner surface of the rivet insert (152) can be in close contact with or in contact with each other, and the outer surface of the collector plate insert (132) and the inner surface of the rivet insert (152) can be provided to be substantially parallel with respect to the first direction.

[0097] Meanwhile, as illustrated in FIG. 7b, the outer diameter surface of the current collector plate injection part (132) and the inner diameter surface of the rivet injection part (152) may be in close contact with or in contact with each other, and the outer diameter surface of the current collector plate injection part (132) and the inner diameter surface of the rivet injection part (152) may be provided to be generally inclined with respect to the first direction. In one or more embodiments, the outer diameter of the current collector plate injection part (132) and the inner diameter of the rivet injection part (152) may gradually decrease as they get farther away from the electrode assembly (120).

[0098] In one or more embodiments, the upper side of the current collector plate housing (132) and the upper side of the rivet housing (152) may be joined to each other by laser welding. In one or more embodiments, a substantially plate-shaped sealing portion (160) may be seated on a rivet recess (154) of the rivet housing (152). In one or more embodiments, a periphery of the sealing portion (160) may be joined to the rivet recess (154) by laser welding. In one or more embodiments, the upper surface of the sealing portion (160) and the upper surface of the rivet terminal (150) (e.g., the upper surface of the upper flange portion (1511)) may form the same surface.

[0099] In one or more embodiments, a sealing ball (163) may be further coupled to the current collector hole (133). In one or more embodiments, the sealing ball (163) may include a polypropylene resin, a polyethylene resin, or a deformable metal ball. The sealing force against the electrolyte may be improved by such a sealing ball (163).

[0100] Fig. 8 is an enlarged cross-sectional view illustrating another positive electrode sealing structure in an exemplary cylindrical secondary battery (100) according to the present invention, and Figs. 9a and 9b are a perspective view and a cross-sectional view illustrating a sealing portion (160) constituting the positive electrode sealing structure in an exemplary cylindrical secondary battery (100) according to the present invention. In Fig. 8, the lightning symbol indicates laser welding.

[0101] As illustrated in FIGS. 8, 9a, and 9b, the sealing portion (160) may include a sealing body portion (161) covering the collector plate injection portion (132) and the rivet injection portion (152), and a sealing protrusion portion (162) coupled to the collector plate injection portion (132). In one or more embodiments, the length of the sealing protrusion portion (162) may be similar to or shorter than the length of the collector plate injection portion (132). In one or more embodiments, the sealing body portion (161) may be seated on the rivet injection portion (152), and further, a perimeter of the sealing body portion (161) may be seated on the rivet recess (154). In one or more embodiments, a perimeter of the sealing body portion (161) may be laser welded to the rivet recess (154).

[0102] FIG. 10 is a cross-sectional view illustrating a sealing portion (160) constituting a positive electrode sealing structure in an exemplary cylindrical secondary battery (100) according to the present invention. As illustrated in FIG. 10, the sealing portion (160) may have a substantially flat shape without a sealing protrusion (162). In one or more embodiments, the sealing portion (160) may include an upper flat portion (163) that is mounted on a current collector plate charging portion (132), a bent portion (164) that is bent downward from the upper flat portion (163), and a lower flat portion (165) that is mounted on a rivet charging portion (152) (i.e., a rivet recess (154)) and is laser-welded.

[0103] FIGS. 11A and 11B are perspective views illustrating a battery pack (300) including an exemplary cylindrical secondary battery according to the present invention. Referring to FIGS. 11A and 11B, the battery pack (300) may include a plurality of battery modules (200) and a housing (310) for accommodating the plurality of battery modules (200). For example, the housing (310) may include first and second housings (311, 312) that are coupled in a direction facing each other with the plurality of battery modules (200) interposed therebetween. The plurality of battery modules (210) may be electrically connected to each other using a bus bar (251), and the plurality of battery modules (200) may be electrically connected to each other in a series / parallel or series-parallel hybrid manner to obtain a required electrical output. In the drawings, for convenience of illustration, components such as a bus bar, a cooling unit, and an external terminal for electrically connecting battery cells are omitted. In one or more embodiments, the battery pack (300) may be mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle may include a four-wheel vehicle or a two-wheel vehicle.

[0104] Figures 12a and 12b are perspective views and side views illustrating a vehicle (400, 500) including an exemplary battery pack (300) according to the present invention. In Figure 12a, the battery pack (300) may include a battery pack cover (311) (which may correspond to the first housing) which is a part of a vehicle underbody (410) and a pack frame (312) (which may correspond to the second housing) which is disposed at a lower portion of the vehicle underbody (410). The battery pack cover (311) and the pack frame (312) may be formed integrally with the vehicle floor (420). The vehicle underbody (410) separates the interior and exterior of the vehicle, and the pack frame (312) may be disposed at the exterior of the vehicle.

[0105] As illustrated in FIG. 12b, the vehicle (500) may be formed by combining additional components, such as a hood (510) at the front of the vehicle and fenders (520) positioned at the front and rear of the vehicle, respectively, with the vehicle body (400). The vehicle (500) includes a battery pack (300) including a battery pack cover (311) and a pack frame (312), and the battery pack (300) may be combined with the vehicle body component (400).

[0106] Although the present invention has been described above with reference to 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 idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. Cylindrical case; An electrode assembly accommodated in the case, comprising a first tab protruding in a first direction and a second tab protruding in a second direction opposite to the first direction and connected to the case; A collector plate that is accommodated in the case and includes a collector plate body part connected to the first tab and a collector plate liquid part provided on the collector plate body part; A cap plate that closes the case so that the electrode assembly and the collector plate are isolated from the outside; A rivet terminal including a rivet body part coupled to the cap plate and a rivet injection part coupled to the collector plate injection part; and A secondary battery comprising a sealing portion that seals the above-mentioned current collector plate liquid portion and the rivet liquid portion.

2. In paragraph 1, A secondary battery, wherein the current collector plate injection portion protrudes in the first direction from the center of the current collector plate body portion and includes a current collector plate injection through hole.

3. In paragraph 2, The rivet body portion includes an upper flange portion extending outwardly horizontally from the upper side of the rivet injection portion and positioned on the upper side of the cap plate with an upper insulator interposed therebetween, and a lower flange extending outwardly horizontally from the lower side of the rivet injection portion and positioned on the lower side of the cap plate with a lower insulator interposed therebetween. A secondary battery, wherein the rivet injection part is penetratedly connected to the cap plate through an insulating gasket, and includes a rivet injection through hole to which the current collector injection part is connected.

4. In paragraph 3, A secondary battery, wherein the outer surface of the above-mentioned current collector plate and the inner surface of the above-mentioned rivet-type portion are in close contact with each other and are provided parallel to the first direction.

5. In paragraph 3, A secondary battery, wherein the outer surface of the above-mentioned current collector plate and the inner surface of the above-mentioned rivet-type portion are in close contact with each other and are provided at an angle with respect to the first direction.

6. In paragraph 5, A secondary battery, wherein the outer diameter of the above-mentioned current collector plate and the inner diameter of the above-mentioned rivet-type portion gradually decrease as they get farther away from the electrode assembly.

7. In paragraph 1, A secondary battery in which the upper side of the above-mentioned current collector plate and the upper side of the above-mentioned rivet-type liquid portion are joined together by laser welding.

8. In paragraph 1, A secondary battery, wherein the sealing portion includes a sealing body portion covering the current collector plate injection portion and the rivet injection portion, and a sealing protrusion portion coupled to the current collector plate injection portion.

9. In paragraph 8, A secondary battery, wherein the rivet main body includes a rivet recess into which the sealing body part is seated.

10. In paragraph 9, A secondary battery in which the circumference of the above sealing body part is laser welded to the above rivet recess.

11. In paragraph 1, Further comprising a sealing ball coupled to the above-mentioned collector plate main body, A secondary battery, wherein the sealing part includes a sealing body part covering the current collector plate liquid part and the rivet liquid part.

12. In paragraph 11, A secondary battery, wherein the rivet main body includes a rivet recess into which the sealing body part is seated.

13. In paragraph 12, A secondary battery in which the circumference of the above sealing body part is laser welded to the above rivet recess.

14. In paragraph 1, A secondary battery, wherein the case includes a bottom portion and a side wall portion extending in the first direction from the periphery of the bottom portion, and the second tab is directly laser-welded to the bottom portion.

15. In paragraph 14, A secondary battery, wherein the bottom portion includes a peripheral portion adjacent to the side wall portion, a vent notch provided in the peripheral portion, and a recessed portion extending inwardly from the peripheral portion and closer to the electrode assembly than the peripheral portion.

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