Rivet Structure of Electrode Terminal, Secondary Battery, Battery Pack, and Automobile Including the Same

Abstract

The present specification provides a rivet structure for an electrode terminal, and a secondary battery including the same, which includes: a battery can having one open side; an electrode terminal riveted through a through-hole formed in the bottom of the battery can; and a gasket interposed between the battery can and the electrode terminal, wherein the electrode terminal includes a body portion inserted into the through-hole; an external flange portion extending from around one side of the body portion exposed through an external surface of the bottom of the battery can along the external surface; and an internal flange portion extending from around the other side of the body portion exposed through an internal surface of the bottom of the battery can toward the internal surface, wherein the body portion and the external flange portion have an internal cavity connected to each other, and the internal flange portion has an opening connected to the internal cavity and opening toward the inside of the battery can.

Description

Technical Field

[0001] The present invention relates to a rivet structure of an electrode terminal, a secondary battery including the same, a battery pack, and an automobile.

[0002] This application claims the benefit of the filing date of Korean Patent Application No. 10-2021-0022867, filed with the Korean Intellectual Property Office on February 19, 2021, and all of its contents are incorporated herein by reference.

Background Art

[0003] Secondary batteries with high applicability according to product groups and having electrical characteristics such as high energy density are widely applied not only to portable devices but also to electric vehicles (EVs), hybrid electric vehicles (HEVs), etc. driven by an electric drive source.

[0004] Such secondary batteries have not only the primary advantage of significantly reducing the use of fossil fuels but also the advantage of generating no by-products due to energy use, so they are environmentally friendly and are attracting attention as a new energy source for improving energy efficiency.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, etc. The operating voltage of such a single secondary battery cell is about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a plurality of batteries are connected in series to form a battery pack. Also, depending on the charge and discharge capacity required for the battery pack, a plurality of batteries may be connected in parallel to form a battery pack. Therefore, the number of batteries included in the battery pack and the electrical connection form can be set variously according to the required output voltage and / or charge and discharge capacity.

[0006] On one hand, as types of secondary battery cells, cylindrical, prismatic, and pouch-type batteries are known. In the case of a cylindrical battery, an insulating separator is interposed between the anode and the cathode, and this is wound up to form a jelly roll-shaped electrode assembly, which is inserted into the interior of a battery can together with an electrolyte to constitute the battery.

[0007] At this time, as the anode electrode terminal of a cylindrical secondary battery, there is also a structure in which instead of the cap of a sealing body that seals the opening of an existing battery can, a rivet-type anode electrode terminal that penetrates the bottom surface of the battery can is applied. However, since the welding process for the connection between the anode electrode terminal and the anode current collector plate has to be performed through the winding core of the jelly roll, there has been difficulty in proceeding with the welding in a narrow space.

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to solve the problem that when attempting laser welding through the winding core inside the can at the upper end of the opening of the battery can, the risk of occurrence of defects such as beam interference, inflow of sputter inside the battery, and weakness of the welding can increase.

Means for Solving the Problems

[0009] This specification includes a battery can with one side open; an electrode terminal riveted through a through-hole formed in the bottom of the battery can; and a gasket interposed between the battery can and the electrode terminal. The electrode terminal includes a body portion inserted into the through-hole; an external flange portion extending along the external surface from around one side of the body portion exposed through the external surface of the bottom of the battery can; and an internal flange portion extending toward the internal surface from around the other side of the body portion exposed through the internal surface of the bottom of the battery can. The body portion and the external flange portion have an internal cavity connected to each other, and the internal flange portion is connected to the internal cavity and has an opening opened in the inner direction of the battery can, providing a rivet structure of the electrode terminal.

[0010] In one embodiment of the present specification, the inner diameter of at least a part of the inner cavity of the external flange portion may be larger than the inner diameter of the body portion.

[0011] In one embodiment of the present specification, the inner diameter of at least a part of the inner cavity of the external flange portion may be such that it becomes smaller as it goes from the outside to the inside of the battery can.

[0012] In one embodiment of the present specification, the thickness of the side surface of the body portion of the electrode terminal may be 5% or more and 40% or less of the maximum distance between the inner surfaces of the body portion.

[0013] In one embodiment of the present specification, the maximum length of the outer surface of the external flange portion may be 10% or more and 40% or less based on the maximum length of the bottom of the battery can.

[0014] One embodiment of the present specification includes an electrode assembly in which a sheet-like first electrode and a second electrode are wound with a separator interposed therebetween, and the plain portions of the first electrode and the second electrode extending and exposed from both side ends; a battery can housing the electrode assembly and electrically connected to the second electrode; an electrode terminal riveted through a through hole formed in the bottom of the battery can and electrically connected to the first electrode, the body portion inserted into the through hole; an external flange portion extending along the external surface from around one side of the body portion exposed through the external surface of the bottom of the battery can; and an internal flange portion extending from around the other side of the body portion exposed through the internal surface of the bottom of the battery can toward the internal surface, the body portion and the external flange portion having an internally connected cavity, the internal flange portion being connected to the internal cavity and having an opening opened in the inner direction of the battery can; a first current collector electrically connected to the plain portion of the first electrode; a gasket interposed between the electrode terminal and the through hole; and a sealing body sealing the open end of the battery can insulatively from the battery can; and provides a secondary battery.

[0015] In one embodiment of the present specification, the plain portion of the first electrode may be welded to the first current collector plate and electrically connected thereto.

[0016] In one embodiment of the present specification, the first current collector plate further includes a fastening portion that is inserted and fitted into the inner cavity of the body portion and the outer flange portion of the electrode terminal through the opening of the inner flange portion of the electrode terminal, and the fastening portion of the first current collector plate may be electrically connected to at least a part of the inner surface of the body portion of the electrode terminal.

[0017] In one embodiment of the present specification, the first current collector plate may be electrically connected to the inner surface of the inner flange portion of the electrode terminal.

[0018] In one embodiment of the present specification, the fastening portion of the first current collector plate may be electrically connected to at least a part of the inner surface of the outer flange portion of the electrode terminal.

[0019] In one embodiment of the present specification, at least a part of the inner diameter of the inner cavity of the outer flange portion of the electrode terminal is larger than the inner diameter of the body portion of the first current collector plate, and the end portion of the fastening portion of the first current collector plate may be formed with a protrusion so as to be riveted inside the outer flange portion.

[0020] In one embodiment of the present specification, the outer diameter of the fastening portion may be larger than the inner diameter of the body portion.

[0021] In one embodiment of the present specification, the ratio of the outer diameter of the fastening portion of the first current collector plate to the inner diameter of the body portion of the electrode terminal may be from 1:1 to 1.01:1.

[0022] In one embodiment of the present specification, the ratio of the maximum outer diameter of the portion of the fastening portion of the first current collector plate provided with the protrusion to the inner diameter of the body portion of the electrode terminal may be from 1.005:1 to 1.1:1.

[0023] One embodiment of this specification provides a battery pack including a plurality of the secondary batteries described above.

[0024] One embodiment of this specification provides a motor vehicle including at least one of the battery packs described above.

Advantages of the Invention

[0025] According to one aspect of the present invention, the structure of the electrode terminal of the secondary battery is improved to eliminate the difficulty in welding in a narrow space and the increase in the risk of defects due to the generation of welding spatter, and further enables the fastening of the electrode terminal and the current collector plate by a simpler process.

Brief Description of the Drawings

[0026]

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Figure 8

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Figure 14

Embodiments for Carrying Out the Invention

[0027] Hereinafter, the present specification will be described in more detail.

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings. The inventor should interpret them as meanings and concepts that conform to the technical idea of the present invention in accordance with the principle that the concept of the terms can be appropriately defined in order to explain his invention in the best way.

[0029] Therefore, it should be understood that the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. There may be various equivalents and modifications that can replace them at the time of this application.

[0030] In addition, for ease of understanding of the present invention, the accompanying drawings are not shown in actual dimensions, and the dimensions of some components may be exaggerated. Also, in different embodiments, the same reference numerals may be assigned to the same components.

[0031] A reference that two objects to be compared are the same means that they are "substantially the same". Thus, being substantially the same may include cases with deviations regarded as low levels in the art, for example, deviations within 5%. Also, in a predetermined region, that a certain parameter is uniform may mean that it is uniform from an average perspective.

[0032] In this specification, "above" does not only mean being physically in contact and located above one layer, but also means being located above when viewed from that position. That is, a layer located above a certain layer may have other layers in between.

[0033] In this specification, when a certain part "includes" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components, but may further include other components.

[0034] This specification provides a riveting structure of an electrode terminal, which includes a battery can with one side open; an electrode terminal riveted through a through hole formed at the bottom of the battery can; and a gasket interposed between the battery can and the electrode terminal. The electrode terminal includes a body part inserted into the through hole; an external flange part extending along the external surface from around one side of the body part exposed through the external surface of the bottom of the battery can; and an internal flange part extending toward the internal surface from around the other side of the body part exposed through the internal surface of the bottom of the battery can. The body part and the external flange part have an internal cavity connected to each other, the internal flange part is connected to the internal cavity and has an opening opened in the inner direction of the battery can.

[0035] When applying an existing rivet - type electrode terminal that penetrates the bottom surface of a battery can as an electrode terminal of a secondary battery, the welding process for bonding between the electrode terminal and the current collector plate has to be carried out through the winding core of the jelly roll. Thus, it has been difficult to proceed with welding in a narrow space. Also, when attempting laser welding through the winding core inside the can at the upper end of the opening of the battery can, the risk of defects such as beam interference, inflow of spatter into the battery, and weakness of the weld increases.

[0036] FIG. 4 is a diagram showing the process in which a current collector plate and a general rivet - type terminal are laser - welded, indicating that spatter generated during welding can remain as metallic foreign matter inside the secondary battery. Thus, when metallic foreign matter remains inside the secondary battery, it can cause a micro - short circuit.

[0037] The electrode terminal 50 of the present invention has a rivet structure and is exposed and riveted through a through - hole 53 formed at the bottom of the battery can 51. At this time, the electrode terminal of the present invention has a structure in which a cavity P is formed inside so that the current collector plate 30 can be fitted into the internal cavity P of the electrode terminal.

[0038] That is, the electrode terminal of the present invention has a structure in which, instead of an electrical connection by welding between the current collector plate and the electrode terminal, the electrode terminal and the current collector plate are in contact with each other and electrically connected by being fitted into each other in the internal cavity. FIG. 5 is a diagram showing the formation process of the electrode terminal having the rivet structure of the present invention. Referring to the figure shown at the bottom, the electrode terminal and the current collector plate of the present invention are fitted at the portion indicated by the dotted line in the cavity formed inside the electrode terminal.

[0039] Therefore, in the secondary battery to which the rivet structure of the electrode terminal of the present invention is applied, since a welding process is not used for bonding between the electrode terminal and the current collector plate, there is an advantage that the risk of defects due to beam interference and generation of welding spatter can be eliminated.

[0040] The electrode terminal of the present invention has a rivet structure and is riveted through a through - hole formed at the bottom of the battery can, and the gasket is provided between the battery can and the electrode terminal.

[0041] FIG. 5 shows the process of processing and riveting the electrode terminal located between the through-holes of the battery can of the present invention. The upper surface of the electrode terminal is bent so that the outer diameter of the portion of the electrode terminal exposed outside the battery can is larger than the outer diameter of the through-hole of the battery can, and a rivet structure of the electrode terminal is formed. At this time, the portion of the gasket exposed outside the battery can is also bent together at the same angle as the electrode terminal by the process of pressing with the pressure. The outer diameter of the through-hole means the diameter of the through-hole.

[0042] The electrode terminal of the present invention that has undergone the above-described processing process includes a body portion 50a inserted into the through-hole 53; an outer flange portion 50b extending along the outer surface 52a from around one side of the body portion 50a exposed through the outer surface 52a of the bottom portion 52 of the battery can 51; and an inner flange portion 50c extending from around the other side of the body portion 50a exposed through the inner surface 52b of the bottom portion 52 of the battery can 51 toward the inner surface 52b. The body portion 50a and the outer flange portion 50b have an internal cavity P connected to each other, and the inner flange portion 50c is connected to the internal cavity P and has an opening Q opened in the inner direction of the battery can 51. Here, the body portion, the outer flange portion, and the inner flange portion are terms defining the region constituting the electrode terminal.

[0043] FIG. 6 is a cross-sectional view of the rivet structure of the electrode terminal of the present invention cut in the longitudinal direction. The region indicated by the dotted line of the portion of the electrode terminal exposed outside the battery can is the outer flange portion 50b, which is provided between the through-holes of the battery can. The region indicated by the dotted line is the body portion 50a, and the portion indicated by the dotted line of the portion where the electrode terminal extends toward the inner surface of the bottom of the battery can is the inner flange portion 50c. The body portion and the outer flange portion include an internal cavity connected to each other, indicated by P in FIG. 6. The inner flange portion has an opening indicated by Q in FIG. 6, and the opening Q is connected to the internal cavity P.

[0044] In one embodiment of the present specification, the inner diameter of at least a part of the inner cavity of the outer flange portion may be larger than the inner diameter of the inner cavity of the body portion. By forming the inner diameter of at least a part of the inner cavity of the outer flange portion to be larger than the inner diameter of the inner cavity of the body portion, one end portion of a current collector plate described later may abut against the inner surface of the outer flange portion and be fixed so that the current collector plate does not move up and down.

[0045] In one embodiment of the present specification, the inner diameter of at least a part of the inner cavity of the outer flange portion may become smaller as going from the outside to the inside of the battery can. Due to the section where the inner diameter of at least a part of the inner cavity of the outer flange portion becomes smaller, one end portion of a current collector plate described later can be more strongly fixed to the inner surface of the outer flange portion.

[0046] In one embodiment of the present specification, the inner surface of the body portion of the electrode terminal may be connected to the inner surface of the inner flange portion without being bent.

[0047] In one embodiment of the present specification, the thickness of the body portion of the electrode terminal may be constant.

[0048] In one embodiment of the present specification, the maximum length between the inner surfaces of the body portion of the electrode terminal may be equal to or smaller than the maximum length between the inner surfaces of the outer flange portion of the electrode terminal.

[0049] In one embodiment of the present specification, the outer flange portion of the electrode terminal may include regions having different thicknesses from each other.

[0050] In one embodiment of the present specification, the thickness t1 of at least a part of the outer flange portion of the electrode terminal may be larger than the thickness t2 of the side surface of the body portion. The thickness of the side surface of the body portion means the distance between the outer surface and the inner surface of the body portion of the electrode terminal, and is indicated by the reference sign t2 in FIG. 6.

[0051] In one embodiment of this specification, the thickness of the side surface of the body portion of the electrode terminal may be 5% or more and 40% or less of the inner diameter R1 of the body portion of the electrode terminal, may be 7% or more and 40% or less, may be 10% or more and 35% or less, or may be 10% or more and 25% or less. The inner diameter of the body portion means the distance between the inner surfaces of the body portion, which is indicated by R1 in FIG. 6.

[0052] When the above range is satisfied, the durability of the body portion can be enhanced, and even if the current collector plate described later is forcibly fitted into the inner cavity of the body portion, while preventing the body portion of the electrode terminal from being damaged, the riveting process of the electrode terminal can be facilitated.

[0053] In one embodiment of this specification, the inner diameter of the body portion, the maximum inner diameter of the inner cavity of the external flange portion, and the inner diameter of the opening of the inner flange portion can be designed according to the thickness of the body portion of the electrode terminal, the diameter of the through-hole of the battery can, and the thickness of the gasket. Specifically, the gap inside the battery can can be blocked by the riveted electrode terminal, and it may also be designed according to the ease of interference fit of the current collector plate described later and the insertion of the fastening portion of the current collector plate.

[0054] In one embodiment of this specification, the inner diameter of the body portion may be 4 mm or more and 11 mm or less, may be 4 mm or more and 8 mm or less, or may be 5 mm or more and 8 mm or less.

[0055] In one embodiment of this specification, the maximum inner diameter of the inner cavity of the external flange portion may be 5 mm or more and 15 mm or less, may be 7 mm or more and 12 mm or less, or may be 9 mm or more and 12 mm or less.

[0056] In one embodiment of this specification, the inner diameter of the opening of the inner flange portion may be 4 mm or more and 11 mm or less, may be 5 mm or more and 10 mm or less, or may be 7 mm or more and 10 mm or less.

[0057] In one embodiment of the present specification, the maximum length of the outer surface of the external flange portion may be 10% or more and 40% or less, 15% or more and 35% or less, or 20% or more and 30% or less based on the maximum length of the bottom of the battery can.

[0058] When the above range is satisfied, a space for welding electrical wiring components such as bus bars to the electrode terminal can be appropriately secured.

[0059] In one embodiment of the present specification, the electrode terminal 50 is made of a conductive metal material. As an example, the electrode terminal 50 may be made of aluminum, but the present invention is not limited thereto.

[0060] In one embodiment of the present specification, the battery can 51 is made of a conductive metal material. As an example, the battery can 51 may be made of a steel material, but the present invention is not limited thereto.

[0061] In one embodiment of the present specification, the gasket 54 may be made of an insulating and elastic polymer resin. As an example, the gasket 54 can be made of polypropylene, polybutylene terephthalate, polytetrafluoroethylene, etc., but the present invention is not limited thereto.

[0062] In one embodiment of the present specification, the upper and lower ends of the inner wall of the through hole 53 perpendicular to the bottom of the battery can 51 are chamfered (corner cutting) so as to form a tapered surface toward the electrode terminal 50. However, the upper and / or lower ends of the inner wall of the through hole 53 may be deformed into a smooth curved surface having a curvature. In this case, the stress applied to the gasket 54 in the vicinity of the upper and / or lower ends of the inner wall of the through hole 53 can be further relaxed.

[0063] According to one embodiment of the present specification, the rivet structure of the electrode terminal 50 may be formed using a caulking jig that moves up and down, a spinning process, or a rotary rivet. First, a preform (not shown) of the electrode terminal 50 to which a gasket is coupled is inserted into a through hole 53 formed in the bottom 52 of the battery can 51. The preform refers to the electrode terminal before being riveted.

[0064] As an example, the preform of the electrode terminal may be processed into a riveted electrode terminal using an external caulking jig from the outside of the battery can, and an internal caulking jig may be inserted into the inner space of the battery can to prevent inner deformation by the external caulking jig.

[0065] After the pressure forming of the preform using the caulking jig is completed and the caulking jig is separated from the battery can 51, as shown in FIG. 6, the rivet structure of the electrode terminal 50 of the present invention can be obtained.

[0066] The gasket 54 is preferably sufficiently compressed so that it can ensure excellent sealing strength without being physically damaged during the process of riveting the preform.

[0067] In one embodiment of the present specification, when the gasket 54 is made of polybutylene terephthalate, the gasket 54 preferably has a compression ratio of 50% or more at the point where it is compressed to the minimum thickness. The compression ratio is the ratio of the change in thickness before and after compression to the thickness before compression.

[0068] In one embodiment of the present specification, when the gasket 54 is made of polytetrafluoroethylene, the gasket 54 preferably has a compression ratio of 60% or more at the point where it is compressed to the minimum thickness.

[0069] In one embodiment of the present specification, when the gasket 54 is made of polypropylene, the gasket 54 preferably has a compression ratio of 60% or more at the point where it is compressed to the minimum thickness.

[0070] The rivet structure of the electrode terminal of the present invention described above may be applied to a secondary battery including an electrode assembly in which a sheet-like first electrode and a second electrode are wound with a separation film interposed therebetween, and the plain portions of the first electrode and the second electrode extending and exposed from both side ends; a first current collector plate welded to the plain portion of the first electrode; a gasket provided between the electrode terminal and the through hole; and a sealing body that insulatingly seals the open end of the battery can.

[0071] In one embodiment of the present specification, the electrode terminal may be coupled to the first current collector plate and electrically connected. Specifically, the electrode terminal is not electrically connected to the first current collector plate by welding, but is electrically connected by direct coupling.

[0072] The first current collector plate further includes a fastening portion that is inserted and fitted into the body portion of the electrode terminal and the internal cavity of the external flange portion through the opening of the internal flange portion of the electrode terminal, and the fastening portion may be electrically connected to at least a part of the inner surface of the body portion. More specifically, the fastening portion may be in direct contact with at least a part of the inner surface of the body portion and electrically connected. FIG. 8 is a diagram illustrating the form of the first current collector plate of the present invention, and has a structure in which a cylindrical fastening portion is coupled to the center portion of a disk-shaped current collector plate.

[0073] By including the fastening portion, the first current collector plate of the present invention can be coupled to the electrode terminal without a welding process. In addition to this advantage, compared with the existing riveted electrode terminal structure, the electrode terminal and the first current collector plate have a wide contact surface, so that they can be smoothly electrically connected, and the high resistance of the first current collector plate can be reduced.

[0074] In one embodiment of the present specification, the fastening portion of the first current collector plate may include a cavity inside.

[0075] In one embodiment of the present specification, the height of the fastening portion of the first current collector plate may be 2 mm or more and 8 mm or less, may be 3 mm or more and 7 mm or less, or may be 4 mm or more and 6 mm or less.

[0076] In one embodiment of the present specification, the first current collector plate may be electrically connected to the inner surface of the inner flange portion of the electrode terminal. More specifically, the first current collector plate may be directly in contact with and electrically connected to the inner surface of the inner flange portion of the electrode terminal.

[0077] In the first current collector plate of the present specification, the opposite surface to the surface joined to the plain portion of the first electrode may be electrically connected to the inner surface of the inner flange portion of the electrode terminal. More specifically, it may be directly in contact with and electrically connected to the inner surface of the inner flange portion of the electrode terminal.

[0078] In one embodiment of the present specification, the fastening portion may be electrically connected to at least a part of the inner surface of the outer flange portion. More specifically, the fastening portion may be directly in contact with and electrically connected to at least a part of the inner surface of the outer flange portion.

[0079] Referring to FIGS. 5 and 6, it shows that the fastening portion of the first current collector plate described above is in direct contact with the electrode terminal.

[0080] The connection structure between the first current collector plate and the electrode terminal in the present specification corresponds to an interference fit connection structure between the electrode terminal and the first current collector. That is, the present invention is configured to be able to remove the risk in the welding process by using a physical contact connection method between the first current collector plate having a fastening portion and the electrode terminal. In FIG. 5, A indicates that the outer surface of the fastening portion of the first current collector plate and the inner surface of the body portion of the electrode terminal are interference fitted.

[0081] In one embodiment of the present specification, the outer diameter L1 of the fastening portion of the first current collector plate may be larger than the inner diameter R1 of the body portion of the electrode terminal.

[0082] In one embodiment of the present specification, the ratio of the outer diameter L1 of the fastening portion of the first current collector plate to the inner diameter R1 of the body portion of the electrode terminal may be 1:1 to 1.01:1, may be 1:1 to 1.008:1, or may be 1:1 to 1.005:1. When the above range is satisfied, the fixing force of the fastening portion of the current collector plate can be enhanced.

[0083] Referring to FIG. 5, the outer diameter of the fastening portion of the first current collector plate means the diameter of the outer surface facing the inner surface of the body portion of the electrode terminal of the fastening portion, which is denoted as L1 in FIG. 5.

[0084] In one embodiment of the present specification, at least a part of the inner diameter of the internal cavity of the external flange portion is larger than the inner diameter of the body portion, and at least one end of the fastening portion may be formed with a protrusion so as to be riveted inside the external flange portion. For example, the protrusion may be located on the side surface of the fastening portion located in the internal cavity of the external flange portion.

[0085] Referring to FIG. 7, the protrusion of the fastening portion of the first current collector plate is riveted by interference fit within the internal cavity of the electrode terminal. Since both the first current collector plate and the electrode terminal are made of conductive metal, when the protrusion of the first current collector plate is fitted into the internal cavity of the electrode terminal with a strong force, each component can be riveted while undergoing minute deformation.

[0086] The maximum outer diameter L2 of the portion where the protrusion of the fastening portion of the first current collector plate is provided may be larger than the inner diameter R1 of the body portion of the electrode terminal.

[0087] In one embodiment of the present specification, the ratio of the maximum outer diameter L2 of the portion where the protrusion of the fastening portion of the first current collector plate is provided to the inner diameter R1 of the body portion of the electrode terminal may be 1.005:1 to 1.1:1, may be 1.005:1 to 1.05:1, may be 1.005:1 to 1.03:1, may be 1.005:1 to 1.02:1, or may be 1.005:1 to 1.015:1.

[0088] When the above range is satisfied, it is preferable in terms of enhancing the fixing force. In the state where the shrink fit is completed, the protrusion catches on the boundary between the body portion and the outer flange portion of the electrode terminal, preventing the first current collector plate from detaching in the opposite direction of insertion.

[0089] Referring to FIG. 7, the maximum outer diameter L2 of the portion of the fastening portion provided with the protrusion means the outer diameter of the fastening portion when based on the portion where the protrusion formed by extending from the outer surface of the fastening portion protrudes the most, and is indicated as L2 in FIG. 7.

[0090] Therefore, when using the rivet structure of the electrode terminal according to the present invention, there is an advantage that there is no need to perform an additional welding process for the electrical connection between the current collector plate and the electrode terminal.

[0091] The first current collector plate of the present invention is combined with the electrode assembly and electrically connected.

[0092] In one embodiment of this specification, the electrode assembly 100 is formed by winding a sheet-like first electrode and a second electrode with a separator interposed therebetween, and includes the plain portions of the first electrode and the second electrode that extend and are exposed from both side ends of the first electrode and the second electrode respectively.

[0093] The electrode assembly according to one embodiment of this specification may have, for example, a jelly-roll structure. The electrode assembly may be manufactured by winding a laminate formed by laminating at least once a sheet-like first electrode and a second electrode with a separator interposed therebetween around a winding center portion.

[0094] That is, the anode plate and the cathode plate have a structure in which the current collector 20 in sheet form is coated with the active material 21, and include a plain portion 22 on one long side along the winding direction. In this case, an additional separator may be provided on the outer peripheral surface of the electrode assembly 100 for insulation from the battery can 51. Any jelly-roll structure known in the art can be applied without being limited to the present invention.

[0095] FIG. 1 shows the structure of a current collector according to an embodiment of the present specification, FIG. 2 shows the winding process of the current collector according to an embodiment of the present specification, and FIG. 3 shows the process of welding a current collecting plate to the bent surface of a plain part according to an embodiment of the present specification.

[0096] Referring to FIGS. 1 to 3, the anode plate 10 and the cathode plate 11 have a structure in which an active material 21 is coated on a sheet-shaped current collector 20, and include a plain part 22 on one long side along the winding direction X.

[0097] The electrode assembly is manufactured by sequentially laminating the anode plate 10 and the cathode plate 11 together with two separator membranes 12 as shown in FIG. 2, and then winding them in one direction X. At this time, the plain parts of the anode plate 10 and the cathode plate 11 are arranged in opposite directions. After the winding process, the plain part 10a of the anode plate 10 and the plain part 11a of the cathode plate 11 are bent toward the core side. Thereafter, a current collecting plate 30 and a second current collecting plate 31 are welded and joined to the plain parts 10a and 11a, respectively.

[0098] Separate electrode tabs are not separately coupled to the anode plain part 10a and the cathode plain part 11a, and the current collecting plate 30 and the second current collecting plate 31 are connected to external electrode terminals, and a current path is formed with a large cross-sectional area along the winding axis direction (see the arrow) of the electrode assembly A. Therefore, there is an advantage that the resistance of the secondary battery can be reduced. This is because the resistance is inversely proportional to the cross-sectional area of the path through which the current flows.

[0099] In an embodiment of the present specification, the first electrode includes a first current collector and an electrode active material layer provided on one or both surfaces of the first current collector. At the long side end portion along the winding direction of the first current collector provided at one end portion of the winding axis of the electrode assembly, there is a plain part of the first electrode where the electrode active material layer is not provided. The plain part of the first electrode is provided at the upper part in the height direction (the direction aligned with the Z axis) of the electrode assembly housed in the battery can. That is, the first current collector includes a plain part of the first electrode where the electrode active material is not coated on the long side end portion and is exposed outside the separator.

[0100] In one embodiment of the present specification, the second electrode includes a second current collector and a second electrode active material layer provided on one or both surfaces of the second current collector. At the other end of the second current collector in the width direction (the direction parallel to the Z-axis), there is a plain portion of the second electrode that does not include the second electrode active material layer.

[0101] The plain portion of the second electrode is provided at the lower part in the height direction (the direction parallel to the Z-axis) of the electrode assembly accommodated in the battery can. That is, the second current collector may include a second plain portion that is not coated with the electrode active material layer at the long-side end and is exposed outside the separator.

[0102] In one embodiment of the present specification, the first electrode may be an anode plate and the second electrode may be a cathode plate.

[0103] In one embodiment of the present specification, the first electrode may be a cathode plate and the second electrode may be an anode plate.

[0104] In one embodiment of the present specification, the anode active material coated on the anode plate and the cathode active material coated on the cathode plate can be used without limitation as long as they are active materials known in the art.

[0105] In one example, the anode active material may include an alkali metal compound represented by the general chemical formula A[A x M y O 2+z (A includes at least one or more elements among Li, Na, and K; M includes at least one or more elements selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; x≧0, 1≦x + y≦2, -0.1≦z≦2; the stoichiometric coefficients x, y, and z are selected so that the compound maintains electrical neutrality).

[0106] In other examples, the anode active material is an alkali metal compound xLiM disclosed in U.S. Patent No. 6,677,082, U.S. Patent No. 6,680,143, etc. 1 O 2- (1-x)Li 2 M 2 O 3 (M 1 contains at least one or more elements having an average oxidation state of 3; M 2 contains at least one or more elements having an average oxidation state of 4; 0 ≦ x ≦ 1) may be used.

[0107] In yet other examples, the anode active material has the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (M 1 contains at least one or more elements selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 contains at least one or more elements selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 contains a halogen group element selectively containing F; 0 < a ≦ 2, 0 ≦ x ≦ 1, 0 ≦ y < 1, 0 ≦ z < 1; the stoichiometric coefficients a, x, y, and z are selected so that the compound maintains electrical neutrality), or Li 3 M 2 (PO 4 ) 3 [M contains at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al] may be a lithium metal phosphate represented by.

[0108] Preferably, the anode active material may include primary particles and / or secondary particles formed by aggregation of the primary particles.

[0109] In one example, the cathode active material may use a carbon material, a lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, etc. Metal oxides such as TiO with a potential less than 2V 2 , SnO 2 can also be used as the cathode active material. As the carbon material, either low-crystalline carbon and / or highly crystalline carbon may be used.

[0110] In one embodiment of the present specification, the separation membrane may use, alone or in a laminated form, a porous polymer film, for example, a porous polymer film made from polyolefin-based polymers such as a homopolymer of ethylene, a homopolymer of propylene, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc. As another example, the separation membrane may use a normal porous nonwoven fabric, for example, a nonwoven fabric made from high-melting glass fibers, polyethylene terephthalate fibers, etc.

[0111] The surface of at least one side of the separation membrane may include a coating layer of inorganic particles. Also, the separation membrane itself may be composed of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bonded to a binder so that an interstitial volume exists between adjacent particles.

[0112] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. As a non-limiting example, the inorganic particles are Pb(Zr, Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), PB(Mg 3 Nb 2 / 3 )O 3- PbTiO 3 (PMN-PT), BaTiO 3 , hafnia (HfO 2 ), SrTiO 3 , TiO 2 , Al 2 O3 , ZrO 2 , SnO 2 , CeO 2 , MgO, CaO, ZnO and Y 2 O 3 may contain at least one or more substances selected from the group consisting of.

[0113] The electrolyte may be a salt having a structure such as A + B - . Here, A + is an ion containing an alkali metal cation such as Li + , Na + , K + or a combination thereof. And B - is F - , Cl - , Br - , I - , NO 3 - , N(CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF 6 - , AsF 6 - , BF 2 C 2 O 4 - , BC 4 O 8 - , (CF 3 ) 2 , PF 4 - , (CF 3 ) 3 , PF 3 - , (CF 3 ) 4 , PF 2 - , (CF 3 ) 5 , PF- , (CF 3 ) 6 P - , CF 3 SO 3 - , C 4 F 9 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (FSO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , (SF 5 ) 3 C - , (CF 3 SO 2 ) 3 C - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - and (CF 3 CF 2 SO 2 ) 2 N - and comprises any one or more anions selected from the group consisting of.

[0114] The electrolyte may also be used by dissolving it in an organic solvent. Examples of the organic solvent include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (ETM), γ-butyrolactone, or a mixture thereof.

[0115] In one embodiment of the present specification, the non-coated portion of the first electrode and / or the second electrode may be bent from the outer peripheral side to the core side of the electrode assembly to form bent surfaces at the upper and lower portions of the electrode assembly. Further, the current collector plate may be welded to the bent surface formed by bending the non-coated portion of the first electrode, and the second current collector plate may be welded to the bent surface formed by bending the non-coated portion of the second electrode.

[0116] In order to relieve the stress generated when the non-coated portion of the first electrode and / or the second electrode is bent, the first electrode and / or the second electrode may have different structures. FIG. 12 is a plan view exemplarily showing the structure of an electrode 90 according to an embodiment of the present invention.

[0117] Referring to FIG. 10, the electrode 90 includes a sheet-like current collector 91, an active material layer 92 formed on at least one surface of the current collector 91, and a non-coated portion 93 at the long side end of the current collector 91 where the active material is not coated.

[0118] The non-coated portion 93 may include a plurality of segmented pieces 93a that have been notched. The plurality of segmented pieces 93a form a plurality of groups, and the segmented pieces 93a belonging to each group may have the same height (length in the Y direction) and / or width (length in the X direction) and / or separation pitch. The number of segmented pieces 93a belonging to each group may be increased or decreased from that shown. The segmented piece 93a may be trapezoidal, or may be deformed into a quadrilateral, a rhombus, a semi-circular shape, or a semi-elliptical shape. Preferably, the height of the segmented piece 93a may increase stepwise from the core side toward the outer peripheral side. Also, the core-side non-coated portion 93' adjacent to the core side may not include the segmented piece 93a, and the height of the core-side non-coated portion 93' may be smaller than the regions of the other non-coated portions.

[0119] In one embodiment of the present specification, the electrode 90 may include an insulating coating layer 94 that covers the boundary between the active material layer 92 and the non-coated portion 93. The insulating coating layer 94 includes an insulating polymer resin and may further selectively include an inorganic filler. The insulating coating layer 94 serves to prevent the end portion of the active material layer 92 from coming into contact with an active material layer of the opposite polarity that faces through the separator, and structurally supports the bending of the segmented piece 93a. For this purpose, when the electrode 90 is wound around the electrode assembly, it is preferable that at least a part of the insulating coating layer 94 is exposed to the outside from the separator.

[0120] FIG. 10 is a cross-sectional view taken along the longitudinal direction Y of an electrode assembly A in which the segmented structure of the non-coated portion of the electrode 90 according to one embodiment of the present specification is applied to a first electrode and a second electrode.

[0121] Referring to FIG. 11, the plain portion 72 protruding downward is extended from the first electrode, and the plain portion 73 protruding upward is extended from the second electrode. A pattern in which the heights of the plain portions 72 and 73 change is schematically shown. That is, the heights of the plain portions 72 and 73 can change irregularly according to the position where the cross section is cut. As an example, when a side portion of the trapezoidal segmented piece 93a is cut off, the height of the plain portion in the cross section becomes lower than the height of the segmented piece 93a. Therefore, it should be understood that the heights of the plain portions 72 and 73 illustrated in the figure showing the cross section of the electrode assembly A correspond to the average of the heights of the plain portions included in each winding pattern.

[0122] As shown in FIG. 12, the plain portions 72 and 73 may be bent from the outer peripheral side to the core side of the electrode assembly A. In FIG. 11, the bent portion 101 is indicated by a dotted box. When the plain portions 72 and 73 are bent, a plurality of adjacent segmented pieces overlap in the radial direction, and bent surfaces 102 are formed at the upper and lower portions of the electrode assembly A. At this time, the plain portion on the core side (93' in FIG. 10) has a low height and is not bent, and the height h of the segmented piece bent from the innermost side is equal to or smaller than the radial length r of the winding region formed by the plain portion 93' on the core side without the structure of the segmented piece. Therefore, the cavity 80 in the core of the electrode assembly A is not closed by the bent segmented pieces. If the cavity 80 is not closed, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved.

[0123] Referring to FIG. 9, a secondary battery according to an embodiment of the present invention includes a cylindrical battery can 51 that houses the electrode assembly 71 and is electrically connected to the plain portion 72 of the first electrode. One side (lower portion) of the battery can 51 is open. Further, the bottom portion 52 of the battery can 51 has a structure in which the above-described electrode terminal 50 is riveted to the through hole 53 through a caulking process.

[0124] In one embodiment of the present specification, the secondary battery may include a gasket provided between the electrode terminal and the through hole.

[0125] Referring to FIG. 9, a secondary battery 70 according to an embodiment of the present specification may also include a sealing body 74 that seals the open end of the battery can 51 in an insulating manner from the battery can 51. Preferably, the sealing body 74 may include a non-polar cap plate 74a and a sealing gasket 74b interposed between the edge of the cap plate 74a and the open end of the battery can 51.

[0126] In the present specification, the cap plate 74a may be made of a conductive metal material such as aluminum, steel, nickel, etc. Also, the sealing gasket 74b may be made of an insulating and elastic material such as polypropylene, polybutylene terephthalate, polytetrafluoroethylene, etc. However, the present invention is not limited by the materials of the cap plate 74a and the sealing gasket 74b.

[0127] In an embodiment of the present specification, the cap plate 74a may include a vent notch 77 that ruptures when the pressure inside the battery can 51 exceeds a threshold value. The vent notch 77 may be formed on both sides of the cap plate 74a. The vent notch 77 may form a continuous or discontinuous circular pattern, linear pattern, or other pattern on the surface of the cap plate 74a.

[0128] In an embodiment of the present specification, the battery can 51 may include a crimping portion 75 that is extended and bent inside the battery can 51 to surround and fix the edge of the cap plate 74a together with the sealing gasket 74b in order to fix the sealing body 74.

[0129] In an embodiment of the present specification, the battery can 51 may also include a beading portion 76 press-fitted inside the battery can 51 in a region adjacent to the open end. The beading portion 76 supports the edge of the sealing body 74, particularly the outer peripheral surface of the sealing gasket 74b, when the sealing body 74 is fixed by the crimping portion 75.

[0130] In one embodiment of this specification, the secondary battery may further include a second current collector plate 31 that is welded to the plain portion 73 of the second electrode. The second current collector plate 31 is made of a conductive metal material such as aluminum, steel, or nickel.

[0131] In one embodiment of this specification, at least a part 78a of the edge of the second current collector plate 31 that does not contact the plain portion 72 of the second electrode may be interposed between the beading portion 76 and the sealing gasket 74b and fixed by the crimping portion 75.

[0132] Optionally, at least a part 78a of the edge of the second current collector plate 31 may be fixed by welding to the inner peripheral surface 76a of the beading portion 76 adjacent to the crimping portion 75.

[0133] In one embodiment of this specification, the insulator may be provided between the first current collector plate and the inner surface of the battery can. The insulator prevents contact between the first current collector plate and the battery can. The insulator may also be interposed between the upper end of the outer peripheral surface of the electrode assembly and the inner surface of the battery can. That is, the insulator may also be interposed between the plain portion of the first electrode and the inner surface of the side wall portion of the battery can. This is to prevent contact between the plain portion of the first electrode extending toward the closed portion of the battery can and the inner peripheral surface of the battery can.

[0134] In one embodiment of this specification, the plain portions 72, 73 of the first electrode and / or the second electrode may be bent from the outer peripheral side to the core side of the electrode assembly 71 to form bent surfaces at the upper and lower portions of the electrode assembly 71. Further, the first current collector plate 30 may be welded to the bent surface formed by bending the plain portion 72 of the first electrode, and the second current collector plate 31 may be welded to the bent surface formed by bending the plain portion 73 of the second electrode.

[0135] To relieve the stress generated when the non-coated portions 72 and 73 are bent, the first electrode and / or the second electrode may have an improved structure different from the electrode plate shown in FIG. 1. FIG. 10 is a plan view exemplarily showing the structure of the electrode plate 90 according to a preferred embodiment of the present invention.

[0136] Referring to FIG. 10, the electrode plate 90 includes a sheet-like current collector 91 made of a conductive material foil, an active material layer 92 formed on at least one surface of the current collector 91, and a non-coated portion 93 at the long side end of the current collector 91 where the active material is not coated.

[0137] Preferably, the non-coated portion 93 may include a plurality of segmented pieces 93a formed by notch processing. The plurality of segmented pieces 93a form a plurality of groups, and the segmented pieces 93a belonging to each group may have the same height (length in the Y direction) and / or width (length in the X direction) and / or separation pitch. The number of segmented pieces 93a belonging to each group may be increased or decreased compared to that shown. The segmented piece 93a may be trapezoidal, or may be deformed into a square, a rhombus, a semi-circle, or a semi-ellipse. Preferably, the height of the segmented piece 93a may increase stepwise from the core side to the outer peripheral side. Also, the non-coated portion 93' on the core side adjacent to the core side may not include the segmented piece 93a, and the height of the core side non-coated portion 93' may be smaller than that of other non-coated portion regions.

[0138] In one embodiment of the present specification, the electrode plate 90 may include an insulating coating layer 94 that covers the boundary between the active material layer 92 and the non-coated portion 93. The insulating coating layer 94 includes an insulating polymer resin and may further selectively include an inorganic filler. The insulating coating layer 94 prevents the end of the active material layer 92 from contacting the active material layer of the opposite polarity facing through the separator, and plays a role of structurally supporting the bending of the segmented piece 93a. For this purpose, when the electrode plate 90 is wound into an electrode assembly, at least a part of the insulating coating layer 94 is preferably exposed to the outside from the separator.

[0139] FIG. 11 is a cross-sectional view of an electrode assembly 100 in which the segmented structure of the plain portions of the electrode plate 90 according to an embodiment of the present invention is applied to the first electrode and the second electrode, taken along the longitudinal direction Y.

[0140] Referring to FIG. 11, the electrode assembly 100 can be manufactured by the winding method described through FIG. 2. For the sake of convenience of explanation, the protruding structures of the plain portions 72, 73 extending outside the separator are shown in detail, and the illustration of the winding structure of the first electrode, the second electrode, and the separator is omitted. The plain portion 72 protruding downward extends from the first electrode, and the plain portion 73 protruding upward extends from the second electrode. The pattern in which the heights of the plain portions 72, 73 change is schematically shown.

[0141] That is, the heights of the plain portions 72, 73 may change irregularly according to the position where the cross-section is cut. As an example, when the side portion of the trapezoidal segmented piece 93a is cut off, the height of the plain portion in the cross-section becomes lower than the height of the segmented piece 93a. Therefore, it should be understood that the heights of the plain portions 72, 73 shown in the figure showing the cross-section of the electrode assembly 100 correspond to the average of the heights of the plain portions included in each winding pattern.

[0142] As shown in FIG. 12, the plain portions 72, 73 may be bent from the outer peripheral side to the core side of the electrode assembly 100. In FIG. 11, the bent portion 101 is indicated by a dotted box. When the plain portions 72, 73 are bent, a plurality of adjacent segmented pieces in the radial direction overlap to form bent surfaces 102 at the upper and lower portions of the electrode assembly 100. At this time, the core-side plain portion (93' in FIG. 10) has a low height and is not bent, and the height h of the segmented piece bent from the innermost side is equal to or smaller than the radial length r of the winding region formed by the core-side plain portion 93' without the structure of the segmented piece. Therefore, the cavity 80 in the core of the electrode assembly 100 is not closed by the bent segmented pieces. If the cavity 80 is not closed, there is no difficulty in the electrolyte injection process, and the efficiency of electrolyte injection is improved.

[0143] In the secondary battery 70 according to an embodiment of the present invention, the cap plate 74a of the sealing body 74 has no polarity. Instead, the second current collector plate 31 is connected to the side wall of the battery can 51, and the outer surface 52a of the bottom 52 of the battery can 51 has a polarity opposite to that of the electrode terminal 50. Therefore, when a plurality of cells are to be connected in series and / or in parallel, wiring such as bus bar connection may be performed from the upper part of the secondary battery 70 using the outer surface 52a of the bottom 52 of the battery can 51 and the electrode terminal 50. Thereby, the number of cells that can be mounted in the same space can be increased, and the energy density can be improved.

[0144] In one embodiment of the present specification, the rivet structure of the electrode terminal 50 is applicable to a cylindrical secondary battery.

[0145] In one embodiment of the present specification, the plain portion of the first electrode of the electrode assembly may be cut in the same form as the current collector plate.

[0146] In one embodiment of the present specification, the bent portion of the plain portion of the first electrode of the electrode assembly may be cut in the same form as the current collector plate.

[0147] In one embodiment of the present specification, the secondary battery may be a cylindrical secondary battery having a form factor ratio (a value defined by dividing the diameter of the cylindrical battery by the height, that is, the ratio of the height H to the diameter Φ) greater than 0.4. Here, the form factor means a value indicating the diameter and height of the cylindrical secondary battery.

[0148] Conventionally, batteries having a form factor ratio of about 0.4 or less have been used. That is, conventionally, for example, 18650 cells, 21700 cells, etc. have been used. In the case of 18650 cells, the diameter is about 18 mm, the height is about 65 mm, and the form factor ratio is about 0.277. In the case of 21700 cells, the diameter is about 21 mm, the height is about 70 mm, and the form factor ratio is about 0.300.

[0149] The cylindrical secondary battery according to an embodiment of the present specification may be a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell. In the numerical value representing the form factor, the first two digits represent the diameter of the cell, the next two digits represent the height of the cell, and the last digit 0 indicates that the cross-section of the cell is circular.

[0150] The secondary battery according to an embodiment of the present specification may be a cylindrical secondary battery having a cylindrical cell with a diameter of 46 mm, a height of 110 mm, and a form factor ratio of 0.418.

[0151] The secondary battery according to an embodiment of the present specification may be a cylindrical secondary battery having a cylindrical cell with a diameter of 48 mm, a height of 75 mm, and a form factor ratio of 0.640.

[0152] The secondary battery according to an embodiment of the present specification may be a cylindrical secondary battery having a cylindrical cell with a diameter of 48 mm, a height of 110 mm, and a form factor ratio of 0.418.

[0153] The secondary battery according to an embodiment of the present specification may be a cylindrical secondary battery having a cylindrical cell with a diameter of 48 mm, a height of 80 mm, and a form factor ratio of 0.600.

[0154] The secondary battery according to an embodiment of the present specification may be a cylindrical secondary battery having a cylindrical cell with a diameter of 46 mm, a height of 80 mm, and a form factor ratio of 0.575.

[0155] The secondary battery according to an embodiment of the present specification may be used to manufacture a battery pack. FIG. 13 is a diagram schematically showing the configuration of a battery pack according to an embodiment of the present invention.

[0156] Referring to FIG. 13, a battery pack 200 according to an embodiment of the present invention includes an assembly in which secondary battery cells 201 are electrically connected and a pack housing 202 that houses the same. The cylindrical secondary battery cells 201 are the secondary battery cells according to the above-described embodiment. In the drawings, for convenience of illustration, illustration of components such as bus bars, cooling units, and external terminals for electrically connecting the cylindrical secondary battery cells 201 is omitted.

[0157] The battery pack 200 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 includes four-wheel vehicles or two-wheel vehicles. FIG. 14 is a diagram for explaining a vehicle including the battery pack 200 of FIG. 13.

[0158] Referring to FIG. 14, a vehicle V according to an embodiment of the present specification includes a battery pack 200 according to an embodiment of the present specification. The vehicle V operates with power supplied from the battery pack 200 according to an embodiment of the present invention.

[0159] As described above, the present invention has been described with reference to limited embodiments and drawings. However, the present invention is not limited thereto, and various modifications and variations can be made by those having ordinary knowledge in the technical field to which the present invention pertains within the equivalent scope of the technical idea of the present invention and the claims described below.

Description of Reference Numerals

[0160] 71, 100 ··· Electrode assembly 10 ··· Anode plate 11 ··· Cathode plate 10a, 73 ··· Plain portion of the first electrode 11a, 72 ··· Plain portion of the second electrode 12 ··· Separator 20, 91 ··· Current collector 21, 92 ··· Active material 22, 93 ··· Plain portion 30 ··· First current collecting plate 30a ··· fastening part L1 ··· outer diameter of the fastening part of the first current collector L2 ··· maximum outer diameter of the part where the protrusion of the fastening part of the first current collector is provided 31, 78 ··· second current collector 50 ··· electrode terminal 50a ··· body part R1 ··· inner diameter of the body part 50b ··· external flange part 50c ··· internal flange part 51 ··· battery can 53 ··· through hole 54 ··· gasket 55 ··· insulator 56 ··· protrusion 70 ··· secondary battery 74 ··· sealing body 74a ··· cap plate 74b ··· sealing gasket 75 ··· crimping part 76 ··· beading part 76a ··· inner circumferential surface of the beading part 77 ··· vent notch 78a ··· at least a part of the edge that does not contact the non-textured part of the second electrode 80 ··· cavity in the core of the electrode assembly 90 ··· electrode 93a ··· segmented piece 93' ··· non-textured part on the core side 94 ··· insulating coating layer 200 ··· battery pack 201 ··· cylindrical secondary battery cell 202 ··· pack housing V ··· automobile P ··· internal cavity Q ··· opening A ··· interference fit

Claims

1. A battery can with one side open; An electrode terminal riveted through a through-hole formed at the bottom of the battery can; and A gasket interposed between the battery can and the electrode terminal, The electrode terminal A body portion inserted into the through-hole; An external flange portion extending along the external surface from around one side of the body portion exposed through the external surface of the bottom of the battery can; and An internal flange portion extending toward the internal surface from around the other side of the body portion exposed through the internal surface of the bottom of the battery can, The body portion and the external flange portion have an internal cavity connected to each other, The internal flange portion is connected to the internal cavity and has an opening portion opened in the inner direction of the battery can, The external flange portion has an inclined surface configured such that the inner diameter of the internal cavity in the external flange portion decreases toward the body portion, The electrode terminal is a rivet structure of the electrode terminal configured such that a current collecting plate is fitted into the internal cavities of the body portion and the external flange portion.

2. The rivet structure of the electrode terminal according to Claim 1, wherein the inner diameter of at least a part of the internal cavity of the external flange portion is larger than the inner diameter of the body portion.

3. The rivet structure of the electrode terminal according to Claim 1 or 2, wherein the thickness of the side surface of the body portion of the electrode terminal is 5% or more and 40% or less of the maximum distance between the inner surfaces of the body portion.

4. The rivet structure of the electrode terminal according to any one of Claims 1 to 3, wherein the maximum length of the outer surface of the external flange portion is 10% or more and 40% or less based on the maximum length of the bottom of the battery can.

5. A sheet-like first electrode and a second electrode are wound with a separator interposed therebetween, and a plain portion of the first electrode extending and exposed from both end portions of the first electrode and An electrode assembly including a plain portion of the second electrode; A battery can housing the electrode assembly and electrically connected to the second electrode; An electrode terminal that is riveted through a through-hole formed in the bottom of the battery can and is electrically connected to the first electrode, the electrode terminal including a body portion inserted into the through-hole; an external flange portion extending along the external surface from around one side of the body portion exposed through the external surface of the bottom of the battery can; and an internal flange portion extending from around the other side of the body portion exposed through the internal surface of the bottom of the battery can toward the internal surface, the body portion and the external flange portion having an internal cavity connected to each other, the internal flange portion being connected to the internal cavity and having an opening opened in the inner side direction of the battery can; A first current collector electrically connected to the non-coated portion of the first electrode; A gasket interposed between the electrode terminal and the through-hole; and A sealing body that seals the open end of the battery can in an insulating manner from the battery can, The first current collector further includes a fastening portion that is inserted and fitted into the internal cavity of the body portion and the external flange portion of the electrode terminal through the opening of the internal flange portion of the electrode terminal; The fastening portion of the first current collector is electrically connected to at least a part of the inner surface of the body portion of the electrode terminal; The inner diameter of at least a part of the internal cavity of the external flange portion of the electrode terminal is larger than the inner diameter of the body portion of the electrode terminal; At least one end of the fastening portion of the first current collector is formed with a protrusion so as to be riveted inside the external flange portion, a secondary battery.

6. A first electrode and a second electrode in sheet form are wound with a separator interposed therebetween, and the non-coated portion of the first electrode extending and exposed from both end portions of the first electrode and An electrode assembly including the non-coated portion of the second electrode; A battery can that houses the electrode assembly and is electrically connected to the second electrode; An electrode terminal riveted through a through hole formed in the bottom of the battery can and electrically connected to the first electrode, the electrode terminal including a body portion inserted into the through hole; an external flange portion extending along the external surface from around one side of the body portion exposed through the external surface of the bottom of the battery can; and an internal flange portion extending from around the other side of the body portion exposed through the internal surface of the bottom of the battery can toward the internal surface, the body portion and the external flange portion having an internal cavity connected to each other, the internal flange portion being connected to the internal cavity and having an opening portion opened in the inner side direction of the battery can; A first current collector plate electrically connected to the non-patterned portion of the first electrode; A gasket interposed between the electrode terminal and the through hole; and A sealing body that insulates from the battery can and seals the open end of the battery can, The first current collector plate further includes a fastening portion that is inserted and fitted into the internal cavity of the body portion and the external flange portion of the electrode terminal through the opening portion of the internal flange portion of the electrode terminal, The fastening portion of the first current collector plate is electrically connected to at least a part of the inner surface of the body portion of the electrode terminal, The outer diameter of the fastening portion of the first current collector plate is larger than the inner diameter of the body portion of the electrode terminal, a secondary battery.

7. The secondary battery according to claim 5 or 6, wherein the non-patterned portion of the first electrode is welded to the first current collector plate and electrically connected.

8. The secondary battery according to any one of claims 5 to 7, wherein the first current collector plate is electrically connected to the inner surface of the internal flange portion of the electrode terminal.

9. The secondary battery according to any one of claims 5 to 8, wherein the fastening portion of the first current collector plate is electrically connected to at least a part of the inner surface of the external flange portion of the electrode terminal.

10. The secondary battery according to claim 5 or 6, wherein the ratio of the outer diameter of the fastening portion of the first current collector plate to the inner diameter of the body portion of the electrode terminal is 1:1 to 1.01:

1.

11. The secondary battery according to claim 5, wherein the ratio of the maximum outer diameter of the portion provided with the protrusion of the fastening portion of the first current collector plate to the inner diameter of the body portion of the electrode terminal is 1.005:1 to 1.1:

1.

12. A battery pack including a plurality of the secondary batteries according to any one of claims 5 to 11.

13. An automobile including at least one battery pack according to claim 12.

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