Riveting structure of electrode terminal and secondary battery, battery pack and automobile including the same

Abstract

This specification provides a riveting structure for electrode terminals and a secondary battery, battery pack, and automobile including the same. The riveting structure for electrode terminals includes: a battery housing with an open side; an electrode terminal riveted through a through hole formed on the bottom surface of the battery housing; and a gasket sandwiched between the battery housing and the electrode terminal. The electrode terminal includes: a main body portion inserted into the through hole; an outer flange portion extending along the outer surface of the main body portion exposed through the outer surface of the bottom surface of the battery housing; and an inner flange portion extending toward the inner surface of the main body portion exposed through the inner surface of the bottom surface of the battery housing. The main body portion and the outer flange portion have internal cavities connected to each other, and the inner flange portion has an opening connected to the internal cavity and opening toward the inside of the battery housing.

Description

TECHNICAL FIELD

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

[0002] This application claims the benefit of the filing date of Korean Patent Application No. 10-2021-0022867 filed on February 19, 2021, in the Korean Intellectual Property Office, the content of which is incorporated herein in its entirety. BACKGROUND

[0003] Secondary batteries having high energy density and the like, which are suitable for use in a wide range of products, are widely used in electric vehicles (EVs) or hybrid electric vehicles (HEVs) and the like, which are driven by an electric power source.

[0004] Such secondary batteries are not only advantageous in that the use of fossil fuels can be greatly reduced, but also advantageous in that no by-products are generated as the energy source is used, and thus are spotlighted as a new energy source for environmental protection and energy efficiency improvement.

[0005] The types of secondary batteries that are widely used at present include lithium ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and the like. The operating voltage of such a unit secondary battery cell is about 2.5 V to 4.5 V. Therefore, in the case where a higher output voltage is required, a plurality of batteries are sometimes 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 are sometimes connected in parallel to form a battery pack. Therefore, depending on the required output voltage and / or charge and discharge capacity, the number of batteries included in the battery pack and the manner of electrical connection can be designed in various ways.

[0006] On the other hand, as a type of unit secondary battery cell, cylindrical, square, and pouch-shaped batteries are disclosed. The cylindrical battery has a separator film, which is an insulator, interposed between an anode and a cathode, and forms an electrode assembly in the shape of a jelly-roll by winding the same, and constitutes a battery by inserting the same into the inside of a battery case together with an electrolyte.

[0007] At this time, as an anode electrode terminal of a cylindrical secondary battery, a structure of an anode electrode terminal of a rivet type that penetrates the bottom surface of the battery case is used instead of a cap of a sealing body that seals the open port of the existing battery case, but a welding process for achieving the bonding between the anode electrode terminal and the anode current collector plate needs to be performed through the winding core of the jelly-roll, and thus there are some difficulties in welding in a narrow space.

[0008] PRIOR ART DOCUMENT

[0009] PATENT LITERATURE

[0010] Korean Patent Laid-Open Publication No. 10-2020-0141200 (Published on December 18, 2020) SUMMARY

[0011] PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] The present invention is to solve the following problem In the case where laser welding is performed on the upper end of the opening portion of the battery case by the winding core inside the case, there is an increased risk of occurrence of adverse effects such as beam interference, inflow of welding slag into the battery, and welding weakness.

[0013] MEANS FOR SOLVING THE PROBLEMS

[0014] In the present specification, a riveting structure of an electrode terminal is provided, which includes a battery case having an open side, an electrode terminal riveted through a through-hole formed in the bottom surface of the battery case, and a gasket sandwiched between the battery case and the electrode terminal, wherein the electrode terminal includes a body portion inserted into the through-hole, an outer flange portion extending from one side edge of the body portion exposed to an outer surface of the bottom surface of the battery case along the outer surface, and an inner flange portion extending from the other side edge of the body portion exposed to an inner surface of the bottom surface of the battery case toward the inner surface, wherein the body portion and the outer flange portion have an inner cavity connected to each other, and the inner flange portion has an opening portion connected to the inner cavity and opened toward the inside direction of the battery case.

[0015] In an embodiment of the present specification, the inner diameter of at least a portion of the inner cavity of the outer flange portion can be larger than the inner diameter of the body portion.

[0016] In an embodiment of the present specification, the inner diameter of at least a portion of the inner cavity of the outer flange portion can decrease as it approaches the inside direction from the outside of the battery case.

[0017] In an embodiment of the present specification, the side surface thickness of the body portion of the electrode terminal can be 5% or more and 40% or less of the maximum distance between the inner surfaces of the body portion.

[0018] In an embodiment of the present specification, the maximum length of the outer surface of the outer flange portion can be 10% or more and 40% or less of the maximum length of the bottom surface of the battery case.

[0019] An embodiment of the present specification provides a secondary battery including: an electrode assembly in which a first electrode and a second electrode in a sheet shape are rolled with a separator interposed therebetween, and including a coating-free portion of the first electrode and a coating-free portion of the second electrode which are exposed from both side end portions; a battery case which accommodates the electrode assembly and is electrically connected to the second electrode; an electrode terminal which is riveted through a through-hole formed in a bottom surface of the battery case and is electrically connected to the first electrode, the electrode terminal including: a main body portion which is inserted into the through-hole; an outer flange portion which extends from one side edge of the main body portion exposed to an outer surface of the bottom surface of the battery case along the outer surface; and an inner flange portion which extends from the other side edge of the main body portion exposed to an inner surface of the bottom surface of the battery case toward the inner surface, wherein the main body portion and the outer flange portion have inner cavities connected to each other, and the inner flange portion has an opening portion connected to the inner cavities and opened toward an inner side direction of the battery case; a first current collecting plate which is electrically connected to the coating-free portion of the first electrode; a gasket which is interposed between the electrode terminal and the through-hole; and a sealing body which seals an open end portion of the battery case so as to enable insulation from the battery case.

[0020] In an embodiment of the present specification, the coating-free portion of the first electrode can be welded to the first current collecting plate to be electrically connected.

[0021] In an embodiment of the present specification, the first current collecting plate further includes a fastening portion which is gripped by the inner cavities of the main body portion and the outer flange portion of the electrode terminal when the first current collecting plate is inserted into the main body portion of the electrode terminal through the opening portion of the inner flange portion of the electrode terminal, and the fastening portion of the first current collecting plate can be electrically connected to at least a portion of the inner surface of the main body portion of the electrode terminal.

[0022] In an embodiment of the present specification, the first current collecting plate can be electrically connected to the inner surface of the inner flange portion of the electrode terminal.

[0023] In an embodiment of the present specification, the fastening portion of the first current collecting plate can be electrically connected to at least a portion of the inner surface of the outer flange portion of the electrode terminal.

[0024] In an embodiment of the present specification, at least a portion of the inner diameter of the inner cavities of the outer flange portion of the electrode terminal can be larger than the inner diameter of the main body portion of the first current collecting plate, and an end portion of the fastening portion of the first current collecting plate is formed with a protrusion so as to be riveted to the inside of the outer flange portion.

[0025] In an embodiment of the present specification, the outer diameter of the fastening portion can be larger than the inner diameter of the main body portion.

[0026] In one embodiment of the present specification, the ratio of the outer diameter of the fastening portion of the first current collecting plate to the inner diameter of the main body portion of the electrode terminal can be 1:1 to 1.01:1.

[0027] 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 collecting plate having the protrusion to the inner diameter of the main body portion of the electrode terminal can be 1.005:1 to 1.1:1.

[0028] One embodiment of the present specification provides a battery pack including a plurality of the above-described secondary batteries.

[0029] One embodiment of the present specification provides an automobile including at least one of the above-described battery packs.

[0030] Effects of Invention

[0031] According to one aspect of the present invention, the electrode terminal structure of the secondary battery is improved, the difficulty in welding in a narrow space and the problems such as an increased risk of poor welding residue are overcome, and the fastening of the electrode terminal and the current collecting plate can be achieved through a simpler process. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a plan view showing the structure of an electrode plate used in a secondary battery.

[0033] Figure 2 is a view showing a winding process of an electrode assembly included in a secondary battery.

[0034] Figure 3 is a view showing Figure 2 a process of welding a current collecting plate to a bending surface of a coating-free portion in the electrode assembly of

[0035] Figure 4 is a view showing the generation of welding residue when an existing rivet-type electrode terminal and a current collecting plate are welded.

[0036] Figure 5 is a view briefly showing a process in which the electrode terminal and the first current collecting plate according to one embodiment of the present specification are clamped.

[0037] Figure 6 is a view briefly showing a riveting structure of the electrode terminal according to one embodiment of the present specification.

[0038] Figure 7 is a cross-sectional view showing that the fastening portion of the first current collecting plate is formed with a protrusion.

[0039] Figure 8 is a schematic view of the first current collecting plate of the present specification.

[0040] Figure 9is a cross-sectional view of a secondary battery cut in a length direction Y according to an embodiment of the present specification.

[0041] Figure 10 is a plan view schematically showing an electrode plate structure according to an embodiment of the present specification.

[0042] Figure 11 is a cross-sectional view of an electrode assembly in which a coating-free portion of an electrode plate is applied to a first electrode and a second electrode cut in a length direction Y according to an embodiment of the present specification.

[0043] Figure 12 is a cross-sectional view of an electrode assembly in which a coating-free portion is bent according to an embodiment of the present specification.

[0044] Figure 13 is a diagram showing a brief configuration of a battery pack including a plurality of cylindrical battery cells according to an embodiment of the present specification.

[0045] Figure 14 is a diagram showing a brief configuration of an automobile including a battery pack according to an embodiment of the present specification.

[0046] Label Explanation

[0047] 71, 100: electrode assembly

[0048] 10: anode plate

[0049] 11: cathode plate

[0050] 10a, 73: coating-free portion of first electrode

[0051] 11a, 72: coating-free portion of second electrode

[0052] 12: separator

[0053] 20, 91: current collector

[0054] 21, 92: active material

[0055] 22, 93: coating-free portion

[0056] 30: first current collecting plate

[0057] 30a: fastening portion

[0058] L1: outer diameter of fastening portion of first current collecting plate

[0059] L2: maximum outer diameter of portion having protrusion in fastening portion of first current collecting plate

[0060] 31, 78: second current collecting plate

[0061] 50: electrode terminal

[0062] 50a: main body portion

[0063] R1: inner diameter of main body portion

[0064] 50b: outer flange portion

[0065] 50c: inner flange portion

[0066] 51: battery case

[0067] 53: through hole

[0068] 54: gasket

[0069] 55: insulator

[0070] 56: protrusion

[0071] 70: secondary battery

[0072] 74: seal body

[0073] 74a: cover plate

[0074] 74b: sealing gasket

[0075] 75: crimped portion

[0076] 76: curled portion

[0077] 76a: inner peripheral surface of curled portion

[0078] 77: venting notch

[0079] 78a: at least a portion of edge not in contact with uncoated portion of second electrode

[0080] 80: cavity in core portion of electrode assembly

[0081] 90: electrode

[0082] 93a: split piece

[0083] 93': core portion side uncoated portion

[0084] 94: insulating coating

[0085] 200: battery pack

[0086] 201: cylindrical secondary battery cell

[0087] 202: battery pack case

[0088] V: automobile

[0089] P: internal cavity

[0090] Q: opening

[0091] A: interference fit DETAILED DESCRIPTION

[0092] Hereinafter, the present specification will be described in more detail.

[0093] Hereinafter, preferred embodiments of the present application will be described in detail with reference to the accompanying drawings. Before conducting the description, the terms and words used in the present specification and the claims should not be interpreted in the meaning of the generally used or the meaning in the dictionary, in view of the principle that the inventor can appropriately define the concept of the terms in order to explain the present application in the best method, and should be interpreted as the meaning and concept in accordance with the technical idea of the present application.

[0094] Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred partial embodiments of the present application, and are not representative of the entire technical idea of the present application, and it should be understood that various equivalents and multiple modifications can exist which can replace these at the time of filing the present application.

[0095] Also, in order to help the understanding of the application, the size of a part of the configuration elements in the drawings is sometimes exaggerated, and is not shown in the actual scale. Also, the same reference numerals can be assigned to the same configuration elements in different embodiments from each other.

[0096] The two comparison objects are the same means "substantially the same". Therefore, substantially the same can include a case having a deviation within a lower level considered in the art, for example, within 5%. Also, being uniform in a certain parameter within a predetermined region can mean uniform from the average angle.

[0097] In the present specification, "upper" means not only physically positioned on one layer, but also located upward from the position viewpoint. That is, there can be other layers between the layers located above a certain layer.

[0098] In the present specification, when a certain part is described as "including" a certain configuration element, in the absence of a special description to the contrary, it means that other configuration elements can also be included, and is not exclusive of other configuration elements.

[0099] In the riveting structure of the electrode terminal provided in the present specification, a battery case is opened at one side, an electrode terminal is riveted through a through-hole formed in the bottom surface of the battery case, and a gasket is interposed between the battery case and the electrode terminal, wherein the electrode terminal includes a main body portion inserted into the through-hole, an outer flange portion extending from one side edge of the main body portion exposed to the outside surface of the bottom surface of the battery case along the outside surface, and an inner flange portion extending from the other side edge of the main body portion exposed to the inside surface of the bottom surface of the battery case toward the inside surface, wherein the main body portion and the outer flange portion have inner cavities connected to each other, and the inner flange portion has an opening portion connected to the inner cavities and opened toward the inside direction of the battery case.

[0100] In the case of using the existing rivet type electrode terminal that penetrates the bottom surface of the battery case as an electrode terminal of a secondary battery, the welding process for realizing the bonding between the electrode terminal and the current collecting plate needs to be performed through the winding core of the gel roll, so there are some difficulties in welding in a narrow space. Also, in the case of performing laser welding through the winding core inside the case at the open portion upper end of the battery case, the risk of occurrence of defects such as beam interference, inflow of welding slag into the battery, and weak welding is increasing.

[0101] Figure 4 is a diagram showing the process of laser welding of the current collecting plate and the general rivet type terminal, and shows an example in which the welding slag generated at the time of welding can remain as a metal impurity inside the secondary battery. In this case, in the case where the metal impurity remains inside the secondary battery, it can become a cause of micro short circuit.

[0102] The electrode terminal 50 of the present invention has a riveting structure exposed after riveting through the through-hole 53 formed in the bottom surface of the battery case 51. At this time, the electrode terminal of the present invention has a structure in which the inner cavity P is formed inside so that the current collecting plate 30 is interposed in the inner cavity P of the electrode terminal.

[0103] That is, the electrode terminal of the present invention has a structure in which the electrode terminal and the current collecting plate are interposed in the inner cavity and abut against each other to realize electrical connection, instead of realizing electrical connection by welding with the current collecting plate. Figure 5 is a diagram showing the forming process of the electrode terminal of the present invention having a riveting structure, and the electrode terminal and the current collecting plate of the present invention are interposed in the portion indicated by a red dotted line formed in the inner cavity of the electrode terminal with reference to the lowermost drawing.

[0104] Therefore, the secondary battery to which the riveting structure of the electrode terminal of the present invention is applied does not use the welding process in bonding the electrode terminal and the current collecting plate, so has the advantage of being able to overcome the risk of occurrence of defects due to beam interference and welding slag.

[0105] The electrode terminal of the present application has a riveting structure, and the gasket is disposed between the battery case and the electrode terminal by riveting through the through hole formed in the bottom surface of the battery case.

[0106] Figure 5 The process of the electrode terminal of the present application between the through holes of the battery case being processed and riveted is shown, the upper surface of the electrode terminal is bent to make the outer diameter of the part of the electrode terminal exposed to the outside of the battery case larger than the outer diameter of the through hole of the battery case, thereby forming the riveting structure of the electrode terminal. At this time, the part of the gasket exposed to the outside of the battery case is also bent at the same angle as the electrode terminal through the process of being pressed by the pressure. The outer diameter of the through hole means the diameter of the through hole.

[0107] The electrode terminal of the present application processed through the process as described above includes the main body part 50a inserted into the through hole 53, the outer flange part 50b extending along the outer surface 52a from the side edge of the main body part 50a exposed to the outer surface 52a through the bottom surface 52 of the battery case 51, and the inner flange part 50c extending toward the inner surface 52b from the other side edge of the main body part 50a exposed to the inner surface 52b through the bottom surface 52 of the battery case 51, the main body part 50a and the outer flange part 50b having the inner cavities P connected to each other, and the inner flange part 50c having the opening part Q connected to the inner cavities P and opened to the inside of the battery case 51. At this time, the main body part, the outer flange part, and the inner flange part are terms for defining the area constituting the electrode terminal.

[0108] Figure 6 is a sectional view of the riveting structure of the electrode terminal of the present application cut in the length direction, the area indicated in a dashed line in the part of the electrode terminal exposed to the outside of the battery case is the outer flange part 50b, the area provided between the through holes of the battery case and indicated in a dashed line is the main body part 50a, and the part indicated in a dashed line in the part of the electrode terminal extending to the inner surface of the bottom surface of the battery case is the inner flange part 50c. The main body part and the outer flange part include the inner cavities P connected to each other in the attached Figure 6 The inner flange part has the opening part Q indicated in Q in the attached Figure 6 The opening part Q is connected to the inner cavities P.

[0109] In one embodiment of the present specification, the inner diameter of at least a part of the inner cavities of the outer flange part can be larger than the inner diameter of the inner cavities of the main body part. By the inner diameter of at least a part of the inner cavities of the outer flange part being formed larger than the inner diameter of the inner cavities of the main body part, the one end part of the current collecting plate described later abuts against the inner surface of the outer flange part, thereby fixing the current collecting plate from moving up and down.

[0110] In one embodiment of the present specification, the inner diameter of at least a portion of the internal cavity of the external flange portion can decrease from the outside of the battery case toward the inside. Through the section in which the inner diameter of at least a portion of the internal cavity of the external flange portion decreases, one end of the collector plate, which will be described later, can be more firmly fixed to the internal surface of the external flange portion.

[0111] In one embodiment of the present specification, the internal surface of the main portion of the electrode terminal can be connected to the internal surface of the internal flange portion in a straight manner.

[0112] In one embodiment of the present specification, the thickness of the main portion of the electrode terminal can be constant.

[0113] In one embodiment of the present specification, the maximum length between the internal surfaces of the main portion of the electrode terminal can be the same as or less than the maximum length between the internal surfaces of the external flange portion of the electrode terminal.

[0114] In one embodiment of the present specification, the external flange portion of the electrode terminal can include regions having different thicknesses from each other.

[0115] In one embodiment of the present specification, the thickness t1 of at least a portion of the external flange portion of the electrode terminal can be greater than the side thickness t2 of the main portion. The side thickness of the main portion refers to the distance between the outer surface and the internal surface of the main portion of the electrode terminal, and is denoted by t2 in the drawing. Figure 6

[0116] In one embodiment of the present specification, the side thickness of the main portion of the electrode terminal can be 5% or more to 40% or less of the inner diameter R1 of the main portion of the electrode terminal, can be 7% or more and 40% or less, can be 10% or more and 35% or less, and can be 10% or more and 25% or less. The inner diameter of the main portion refers to the distance between the internal surfaces of the main portion, and is denoted by R1 in the drawing. Figure 6

[0117] In the case where the above range is satisfied, the durability of the main portion can be improved, so that even if the collector plate, which will be described later, is forced to sandwich the internal cavity of the main portion, the main portion of the electrode terminal can be prevented from being damaged, and the riveting process of the electrode terminal can be easily performed.

[0118] ​​In one embodiment of the present specification, the inner diameter of the main body portion, the maximum inner diameter of the internal cavity of the external flange portion, and the inner diameter of the opening portion of the internal flange portion can be designed according to the thickness of the main body portion of the electrode terminal, the diameter of the through hole of the battery case, and the thickness of the gasket, and specifically, can be designed according to the easiness of plugging the gap inside the battery case by the riveted electrode terminal, the interference fit of the collector plate described later, and the insertion of the fastening portion of the collector plate.

[0119] In one embodiment of the present specification, the inner diameter of the main body portion can be 4 mm or more and 11 mm or less, can be 4 mm or more and 8 mm or less, and can be 5 mm or more and 8 mm or less.

[0120] In one embodiment of the present specification, the maximum inner diameter of the internal cavity of the external flange portion can be 5 mm or more and 15 mm or less, can be 7 mm or more and 12 mm or less, and can be 9 mm or more and 12 mm or less.

[0121] In one embodiment of the present specification, the inner diameter of the opening portion of the internal flange portion can be 4 mm or more and 11 mm or less, can be 5 mm or more and 10 mm or less, and can be 7 mm or more and 10 mm or less.

[0122] In one embodiment of the present specification, the maximum length of the outer surface of the external flange portion can be 10% or more and 40% or less based on the maximum length of the bottom surface of the battery case, can be 15% or more and 35% or less, and can be 20% or more and 30% or less.

[0123] In the case of satisfying the above range, the space of the electronic wiring member such as the weldable bus bar can be appropriately ensured in the electrode terminal.

[0124] In one embodiment of the present specification, the electrode terminal 50 is configured of an electrically conductive metal material. In one example, the electrode terminal 50 can be configured of aluminum, but the present application is not limited thereto.

[0125] In one embodiment of the present specification, the battery case 51 is configured of an electrically conductive metal material. In one example, the battery case 51 can be configured of a steel material, but the present application is not limited thereto.

[0126] In one embodiment of the present specification, the gasket 54 can be configured of a high molecular resin having insulation and elasticity. In one example, the gasket 54 can be configured of polypropylene, polybutylene terephthalate, polyfluoroethylene, or the like, but the present application is not limited thereto.

[0127] In one embodiment of the present specification, the upper end and the lower end of the inner wall of the through-hole 53 perpendicular to the bottom surface of the battery case 51 are subjected to corner cutting processing so as to form a tapered surface toward the electrode terminal 50. However, the upper end and / or the lower end of the inner wall of the through-hole 53 can be deformed into a soft curved surface having a curvature. In this case, the pressure applied to the gasket 54 near the upper end and / or the lower end of the inner wall of the through-hole 53 can be further alleviated.

[0128] According to one embodiment of the present specification, the riveting structure of the electrode terminal 50 can be formed using a calking jig that moves up and down, a spinning process, or a rotary riveting. First, a preform (not shown) of the electrode terminal 50 to which the gasket is combined is inserted into the through-hole 53 formed in the bottom surface 52 of the battery case 51. The preform refers to the electrode terminal before the riveting is achieved.

[0129] As an example, on the outside of the battery case, the preform of the electrode terminal is processed into a riveted electrode terminal using an external calking jig, and an internal calking jig is inserted into the inside space of the battery case, so that the inside deformation caused by the above-mentioned external calking jig can be blocked.

[0130] After the press forming of the preform using the calking jig is completed, the calking jig is separated from the battery case 51, and then Figure 6 As shown, the riveting structure of the electrode terminal 50 of the present application can be obtained.

[0131] Preferably, the above-mentioned gasket 54 is sufficiently compressed so as not to be physically damaged during the riveting of the preform while being able to ensure excellent sealing strength.

[0132] In one embodiment of the present specification, preferably, in the case where the gasket 54 is composed of polybutylene terephthalate, the compression rate of the gasket 54 is 50% or more at the point in time when the gasket 54 is compressed to the lowest thickness. The compression rate is the ratio of the change in thickness before and after compression with respect to the thickness before compression.

[0133] In one embodiment of the present specification, preferably, in the case where the above-mentioned gasket 54 is composed of polyvinyl fluoride, the compression rate of the gasket 54 is 60% or more at the point in time when the gasket 54 is compressed to the lowest thickness.

[0134] In one embodiment of the present specification, preferably, in the case where the above-mentioned gasket 54 is composed of polypropylene, the compression rate of the gasket 54 is 60% or more at the point in time when the gasket 54 is compressed to the lowest thickness.

[0135] The riveting structure of the electrode terminal of the present application described above can be applied to a secondary battery including: an electrode assembly in which first and second electrodes in a sheet shape are wound in a state of sandwiching a separator and including uncoated portions of the first electrode and the second electrode exposed from both side end portions; a first current collecting plate welded to the uncoated portion of the first electrode; a gasket provided between the electrode terminal and the through hole; and a sealing body sealing an open end portion of the battery case so as to achieve insulation with the battery case.

[0136] In an embodiment of the present specification, the electrode terminal can be combined and electrically connected with the first current collecting plate. Specifically, the electrode terminal is electrically connected with the first current collecting plate by direct combination, not by welding.

[0137] The first current collecting plate further includes a fastening portion through which the main body portion of the electrode terminal and the inner cavity of the outer flange portion are inserted and clamped through the opening portion of the inner flange portion of the electrode terminal, and the fastening portion can be electrically connected with at least a portion of the inner surface of the main body portion. More specifically, the fastening portion can be directly in contact with at least a portion of the inner surface of the main body portion to achieve electrical connection. Figure 8 is a schematic view of the first current collecting plate of the present application, having a structure in which a cylindrical fastening portion is combined at the center portion of a disc-shaped current collecting plate.

[0138] The first current collecting plate of the present application, by including the fastening portion, has a wider contact surface with the electrode terminal compared to the existing riveted electrode terminal structure, in addition to the advantage of being able to be combined with the electrode terminal without a welding process, so that it can be smoothly electrically connected with the electrode terminal, while reducing the high resistance of the first current collecting plate.

[0139] In an embodiment of the present specification, the fastening portion of the first current collecting plate can include a cavity in the inside.

[0140] In an embodiment of the present specification, the height of the fastening portion of the first current collecting plate can be 2 mm or more to 8 mm or less, can be 3 mm or more to 7 mm or less, and can be 4 mm or more to 6 mm or less.

[0141] In an embodiment of the present specification, the first current collecting plate can be electrically connected with the inner surface of the inner flange portion of the electrode terminal. More specifically, the first current collecting plate can be directly in contact with and electrically connected with the inner surface of the inner flange portion of the electrode terminal.

[0142] In the first current collecting plate of the present specification, the side opposite to the side combined with the uncoated portion of the above-described first electrode can be electrically connected with the inner face of the inner flange portion of the above-described electrode terminal, and more specifically, can be directly contacted and electrically connected with the inner face of the inner flange portion of the above-described electrode terminal.

[0143] In an embodiment of the present specification, the above-described fastening portion can be electrically connected with at least a portion of the inner face of the above-described outer flange portion. More specifically, the above-described fastening portion can be directly contacted and electrically connected with at least a portion of the inner face of the above-described outer flange portion.

[0144] Referring to Figure 5 , and Figure 6 , the case where the above-described fastening portion of the above-described first current collecting plate is directly contacted with the above-described electrode terminal is shown.

[0145] The connection structure of the first current collecting plate and the electrode terminal of the present specification corresponds to the interference fit combination structure between the electrode terminal and the first current collecting body. That is, the present invention is configured to remove the danger caused by the welding process using the physical contact connection method of the first current collecting plate having the fastening portion and the electrode terminal. Figure 5 In the above-described embodiment, the interference fit between the outer face of the fastening portion of the first current collecting plate and the inner face of the main body portion of the electrode terminal is indicated by A.

[0146] In an embodiment of the present specification, the outer diameter L1 of the fastening portion of the above-described first current collecting plate can be larger than the inner diameter R1 of the main body portion of the above-described electrode terminal.

[0147] In an embodiment of the present specification, the ratio of the outer diameter L1 of the fastening portion of the above-described first current collecting plate to the inner diameter R1 of the main body portion of the above-described electrode terminal can be 1:1 to 1.01:1, and can be 1:1 to 1.008:1, and can be 1:1 to 1.005:1. In the case where the above-described range is satisfied, the fixing force of the fastening portion of the current collecting plate can be strengthened.

[0148] Referring to Figure 5 , the outer diameter of the fastening portion of the above-described first current collecting plate indicates the diameter in the outer face of the above-described fastening portion opposite to the inner face of the main body portion of the above-described electrode terminal, and in the above-described embodiment, is indicated by L1. Figure 5

[0149] In an embodiment of the present specification, the inner diameter of at least a portion of the inner cavity of the above-described outer flange portion can be larger than the inner diameter of the above-described main body portion, and at least one end portion of the above-described fastening portion can be formed with a protrusion so as to be riveted with the inner portion of the above-described outer flange portion. For example, the above-described protrusion can be located at the side face of the fastening portion in the inner cavity of the above-described outer flange portion.

[0150] Referring to Figure 7 ​In the internal cavity of the electrode terminal, the protrusion of the fastening portion of the first current collecting plate is riveted by interference fit. Since the first current collecting plate and the electrode terminal are each made of an electrically conductive metal, the protrusion of the first current collecting plate is clamped in the internal cavity of the electrode terminal with a strong force, and each of the constituent elements is slightly deformed and riveted at the same time.

[0151] The maximum outer diameter L2 of the portion of the fastening portion of the first current collecting plate, in which the protrusion is provided, can be larger than the inner diameter R1 of the main body portion of the electrode terminal.

[0152] In one embodiment of the present specification, the ratio of the maximum outer diameter L2 of the portion of the fastening portion of the first current collecting plate, in which the protrusion is provided, to the inner diameter R1 of the main body portion of the electrode terminal can be 1.005:1 to 1.1:1, can be 1.005:1 to 1.05:1, can be 1.005:1 to 1.03:1, can be 1.005:1 to 1.02:1, or can be 1.005:1 to 1.015:1.

[0153] When the above range is satisfied, it is relatively preferable in terms of enhancing the fixing force, and the protrusion is blocked at the boundary between the main body portion and the external flange portion of the electrode terminal in a state where interference fit clamping is completed, so that the first current collecting plate can be prevented from being inserted and detached in the opposite direction.

[0154] Reference Figure 7 The maximum outer diameter L2 of the portion of the fastening portion, in which the protrusion is provided, indicates the outer diameter of the fastening portion when the portion in which the protrusion protrudes the most is taken as a reference, and in Figure 7 L2 is indicated.

[0155] Therefore, when the riveting structure of the electrode terminal according to the present application is used, it has the advantage that a welding process, which is additionally performed for electrical connection of the current collecting plate and the electrode terminal, is not required.

[0156] The first current collecting plate of the present application is combined with and electrically connected to the electrode assembly.

[0157] In one embodiment of the present specification, in the electrode assembly 100, the first electrode and the second electrode having a sheet shape are wound in a state in which the separator membrane is interposed therebetween, and the uncoated portion of the first electrode and the uncoated portion of the second electrode, which are exposed from both side end portions of each of the first electrode and the second electrode, are included.

[0158] The electrode assembly according to one embodiment of the present specification can have, for example, a jelly-roll structure. The electrode assembly can be manufactured by winding a laminate formed by laminating the first electrode and the second electrode having a sheet shape in a state in which the separator membrane is interposed therebetween at least once, with the winding center portion as a reference.

[0159] That is, the anode plate and the cathode plate have a structure in which the active material 21 is coated on the sheet-shaped current collector 20, and include the uncoated portion 22 on one side of the long side in the winding direction. In this case, an additional separator film can be provided on the outer circumferential surface of the above-described electrode assembly 100 for achieving insulation from the battery case 51. As long as it is a jelly-roll structure known in the art, it is not limited in any way.

[0160] Figure 1 A structure of a current collector according to an embodiment of the present specification is shown, Figure 2 A winding process of a current collector according to an embodiment of the present specification is shown, Figure 3 A process of welding a current collector plate to a bending surface of an uncoated portion according to an embodiment of the present specification is shown.

[0161] Referring to Figures 1 to 3 The anode plate 10 and the cathode plate 11 have a structure in which the active material 21 is coated on the sheet-shaped current collector 20, and include the uncoated portion 22 on one side of the long side in the winding direction X.

[0162] As Figure 2 It is shown that the anode plate 10 and the cathode plate 11 are sequentially stacked with two sheets of the separator film 12 and then wound in one direction X, thereby manufacturing an electrode assembly. At this time, the uncoated portions of the anode plate 10 and the cathode plate 11 are disposed in opposite directions to each other. After the winding process, the uncoated portion 10a of the anode plate 10 and the uncoated portion 11a of the cathode plate 11 are bent toward the core side. Thereafter, the current collector plate 30 and the second current collector plate 31 are respectively welded and coupled to the uncoated portions 10a and 11a.

[0163] The anode uncoated portion 10a and the cathode uncoated portion 11a do not have other electrode sheets coupled thereto, the current collector plate 30 and the second current collector plate 31 are connected to the external electrode terminal, and form a current passage having a large cross-sectional area in the winding axis direction (refer to the arrow) of the electrode assembly A, so as to have an advantage of being able to reduce the resistance of the secondary battery. This is because the resistance is inversely proportional to the cross-sectional area of the passage through which the current flows.

[0164] In the embodiment of the present specification, the above-described first electrode includes an electrode active material layer provided on the first current collector and one or both surfaces of the above-described first current collector. There is an uncoated portion of the first electrode, which does not have the electrode active material layer, on the long side end portion in the winding direction of the above-described first current collector provided on one end portion of the winding axis of the electrode assembly. The uncoated portion of the above-described first electrode is provided on the upper portion in the height direction (the direction parallel to the Z axis) of the electrode assembly accommodated in the battery case. That is, the above-described first current collector includes the uncoated portion of the first electrode, which is not coated with the electrode active material and exposed to the outside of the separator film, on the long side end portion.

[0165] In one embodiment of the present specification, the second electrode includes a second electrode active material layer provided on the second electrode current collector and one or both surfaces of the second electrode current collector. The second electrode has a coating-free portion not including the second electrode active material layer at the other end portion in the width direction (the direction parallel to the Z axis) of the second electrode current collector.

[0166] The coating-free portion of the second electrode is provided at the lower portion in the height direction (the direction parallel to the Z axis) of the electrode assembly housed in the battery case. That is, the second electrode current collector can include a second coating-free portion not coated with the electrode active material layer and exposed to the outside of the separator at the long edge end portion.

[0167] In one embodiment of the present specification, the first electrode can be an anode plate and the second electrode can be a cathode plate.

[0168] In one embodiment of the present specification, the first electrode can be a cathode plate and the second electrode can be an anode plate.

[0169] 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 employ active materials known in the art without any limitation.

[0170] In one example, the anode active material can include an alkaline metal compound represented by the general chemical formula A[A x M y ]O 2+z (A includes at least one or more elements selected from 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 in such a manner that the compound maintains electrical neutrality).

[0171] In another example, the anode active material can be an alkaline metal compound xLiM 1 O2-(1-x)Li2M 2 O3(M 1 including at least one or more elements having an average oxidation state of 3; M 2 including at least one or more elements having an average oxidation state of 4; 0 ≤ x ≤ 1) disclosed in US Registered Patent No. 6,677,082, US Registered Patent No. 6,680,143, etc.

[0172] In still another example, the anode active material can be an alkaline metal compound LiaM 1 x Fe 1-x M2 yP 1-y M 3 zO 4-z (M 1 comprises at least one or more elements selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 comprises 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 comprises halogen elements optionally including F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; the stoichiometric coefficients a, x, y, and z are selected in such a way that the compound maintains electrical neutrality) or lithium metal phosphate represented by Li3M2(PO4)3 [M comprises at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al].

[0173] Preferably, the anode active material may comprise primary particles and / or secondary particles aggregated from the primary particles.

[0174] In one example, carbon materials, lithium metal or lithium metal compounds, silicon or silicon compounds, tin or tin compounds, etc. may be used as the cathode active material. Metal oxides such as TiO2 and SnO2 with a potential less than 2V may also be used as the cathode active material. Low-crystalline carbon and / or high-crystalline carbon, etc. may be used as the carbon material.

[0175] In one embodiment of the present specification, the above-mentioned separation membrane may use a porous polymer film. For example, a porous polymer film made of polyolefin-based polymers such as ethylene monomer polymer, propylene monomer polymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc. may be used alone, or they may be laminated and used. As another example, the separation membrane may use a conventional porous non-woven fabric, such as a non-woven fabric composed of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0176] At least one surface of the separation membrane may comprise a coating of inorganic particles. Also, the separation membrane itself may be composed of a coating of inorganic particles. The particles constituting the coating may have a structure combined with an adhesive so that there is an interstitial volume between adjacent particles.

[0177] The inorganic particles may be composed of an inorganic substance with a dielectric constant of 5 or more. As a non-limiting example, the above-mentioned inorganic particles may include those selected from Pb(Zr,Ti)O3 (PZT), Pb 1-x La xZr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0178] The electrolyte can be a salt having a structure of A + B - . Among them, A + includes Li + , Na + , K + , and the like alkaline metal cations or ions composed of a combination thereof. In addition, B - includes halogen ions selected from the group consisting of F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4- - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3, CF3CF2SO3 -- , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2, SCN - , and (CF3CF2SO2)2N- - any one or more of the anions of the group consisting of.

[0179] The electrolyte can also be dissolved in an organic solvent. As the organic solvent, 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 (EMC), γ butyrolactone, or a mixture thereof can be used.

[0180] In one embodiment of the present specification, the uncoated portion of the first electrode and / or the second electrode is bent from the outer periphery of the electrode assembly toward the core portion, so that a bent surface can be formed at the upper portion and the lower portion of the electrode assembly. Also, the current collector can be welded to the bent surface formed by the bending of the uncoated portion of the first electrode, and the second current collector can be welded to the bent surface formed by the bending of the uncoated portion of the second electrode.

[0181] In order to relieve the stress generated when the uncoated portion of the first electrode and / or the second electrode is bent, the first electrode and / or the second electrode can have different structures. Figure 12 is a plan view schematically showing the structure of an electrode 90 according to one embodiment of the present application.

[0182] Referring to Figure 10 The electrode 90 includes a current collector 91 in a sheet shape, an active material layer 92 formed on at least one surface of the current collector 91, and an uncoated portion 93 in which the active material is not coated on the long edge end portion of the current collector 91.

[0183] The above-mentioned coating-free portion 93 can include a plurality of slits 93a cut. The plurality of slits 93a are formed into a plurality of groups, and the height (Y-direction length) and / or the width (X-direction length) and / or the interval of the plurality of slits 93a belonging to each group can be the same. The number of the plurality of slits 93a belonging to each group can be increased or decreased from the number shown in the drawing. The slit 93a can be trapezoidal, and can also be deformed into a quadrangle, a parallelogram, a semicircle, or a semioval. Preferably, the height of the slit 93a can be gradually increased from the core side toward the outer periphery. Also, a core side coating-free portion 93' adjacent to the core side can not include the slit 93a, and the height of the core side coating-free portion 93' can be smaller than that of the other coating-free portion.

[0184] In one embodiment of the present specification, the above-mentioned electrode 90 can include an insulating coating 94 covering the boundary between the active material layer 92 and the coating-free portion 93. The insulating coating 94 includes a high-molecular resin having insulating properties, and can also selectively include an inorganic filler. The insulating coating 94 prevents the end of the active material layer 92 from contacting the opposite polarity active material layer through the separator, and functions to structurally support the bending of the slit 93a. For this reason, when the electrode 90 is wound into an electrode assembly, at least a part of the insulating coating 94 is preferably exposed from the separator to the outside.

[0185] Figure 10 is a cross-sectional view of an electrode assembly A in which the coating-free portion of the electrode 90 is cut in the length direction Y and the structure is applied to the first electrode and the second electrode according to one embodiment of the present specification.

[0186] Referring to Figure 13 , the coating-free portion 72 protruding downward is extended from the first electrode, and the coating-free portion 73 protruding upward is extended from the second electrode. The pattern of the change in the height of the above-mentioned coating-free portions 72, 73 is briefly shown. That is, depending on the position at which the cross section is cut, the height of the coating-free portions 72, 73 can be irregularly changed. As an example, if the side portion of the trapezoidal slit 93a is cut, the height of the coating-free portion in the cross section is lower than the height of the slit 93a. Therefore, it should be interpreted that the height of the coating-free portions 72, 73 shown in the drawing showing the cross section of the electrode assembly A corresponds to the average of the height of the coating-free portion included in each winding loop.

[0187] As Figure 12 shown, the above-mentioned coating-free portions 72, 73 can be bent toward the core side from the outer periphery of the electrode assembly A. In Figure 11 , the portion 101 bent is indicated by a dotted line frame. When the coating-free portions 72, 73 are bent, a plurality of slits adjacent in the radial direction overlap each other in multiple layers, and a bent surface 102 is formed in the upper and lower portions of the electrode assembly A. At this time, the core side coating-free portion (Figure 10 The slit pieces 93' on the inside are not bent due to the low height, and the height h of the slit pieces on the inside is the same as or less than the radial length r of the coiling region formed by the uncoated portion 93' of the core portion side where there are no slit pieces. Thus, the cavity 80 of the core portion of the electrode assembly A is not closed by the bent slit pieces. If the cavity 80 is not closed, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved.

[0188] Referring to Figure 9 According to an embodiment of the present invention, a secondary battery includes a cylindrical battery case 51 that houses an electrode assembly 71 and is electrically connected to an uncoated portion 72 of a first electrode. The battery case 51 is open on one side (lower portion). Also, the bottom surface 52 of the battery case 51 has a structure in which the electrode terminal 50 is riveted to the through hole 53 through a caulking process.

[0189] In an embodiment of the present invention, the secondary battery can include a gasket provided between the electrode terminal and the through hole.

[0190] Referring to Figure 9 According to an embodiment of the present invention, the secondary battery 70 can further include a sealing body 74 that seals the open end portion of the battery case 51 so as to be insulated from the battery case 51. Preferably, the sealing body 74 can include a cover plate 74a having no polarity and a sealing gasket 74b interposed between the edge of the cover plate 74a and the open end portion of the battery case 51.

[0191] In the present invention, the cover plate 74a can be made of a conductive metal material such as aluminum, steel, nickel, etc. Also, the sealing gasket 74b can be made of polypropylene, polybutylene terephthalate, polyvinyl fluoride, etc. that have insulation and elasticity. However, the present invention is not limited to the materials of the cover plate 74a and the sealing gasket 74b.

[0192] In an embodiment of the present invention, the cover plate 74a can include a venting notch 77 that is broken when the pressure inside the battery case 51 exceeds a threshold value. The venting notch 77 can be formed on both surfaces of the cover plate 74a. The venting notch 77 can form a continuous or discontinuous circular pattern, a straight line pattern, or a pattern other than the above on the surface of the cover plate 74a.

[0193] In an embodiment of the present invention, the battery case 51 can include a crimped portion 75 that extends inward of the battery case 51 and is bent so as to surround and fix the edge of the cover plate 74a together with the sealing gasket 74b in order to fix the sealing body 74.

[0194] In one embodiment of the present specification, the battery case 51 can include a crimped portion 76 pressed inwardly of the battery case 51 in a region adjacent to the open end. When the seal 74 is fixed by the crimped portion 75, the crimped portion 76 supports the edge of the seal 74, particularly the outer circumferential surface of the gasket 74b.

[0195] In one embodiment of the present specification, the secondary battery can further include a second current collecting plate 31 welded to the uncoated portion 73 of the second electrode. The second current collecting plate 31 is made of an electrically conductive metal material such as aluminum, steel, nickel, etc.

[0196] In one embodiment of the present specification, at least a portion 78a of the edge of the second current collecting plate 31 not in contact with the uncoated portion 72 of the second electrode is sandwiched between the crimped portion 76 and the gasket 74b and is fixed by the crimped portion 75.

[0197] Alternatively, at least a portion 78a of the edge of the second current collecting plate 31 can be fixed to the inner circumferential surface 76a of the crimped portion 76 adjacent to the crimped portion 75 by welding.

[0198] In one embodiment of the present specification, an insulator can be provided between the first current collecting plate and the inner side surface of the battery case. The insulator prevents contact between the first current collecting plate and the battery case. The insulator can also be sandwiched between the outer circumferential surface of the electrode assembly and the inner side surface of the battery case. That is, the insulator can also be sandwiched between the uncoated portion of the first electrode and the inner side surface of the side wall portion of the battery case. This is to prevent contact between the uncoated portion of the first electrode extending toward the closed portion of the battery case and the inner circumferential surface of the battery case.

[0199] In one embodiment of the present specification, the uncoated portions 72, 73 of the first and / or second electrodes are bent from the outer circumference of the electrode assembly 71 toward the core portion, so that bent surfaces can be formed at the upper and lower portions of the electrode assembly 71. Also, the first current collecting plate 30 can be welded to the bent surface formed by the bending of the uncoated portion 72 of the first electrode, and the second current collecting plate 31 can be welded to the bent surface formed by the bending of the uncoated portion 73 of the second electrode.

[0200] To relieve stress generated when the uncoated portions 72, 73 are bent, the first and / or second electrodes can have a structure different from that of the electrode plate shown in the drawing. Figure 1 is a plan view schematically showing the structure of an electrode plate 90 according to a preferred embodiment of the present invention. Figure 10 is a plan view schematically showing the structure of an electrode plate 90 according to a preferred embodiment of the present invention.

[0201] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Figure 8The electrode plate 90 includes a sheet-shaped current collector 91 made of a conductive foil material, an active material layer 92 formed on at least one side of the current collector 91, and an uncoated portion 93 at the long side end of the current collector 91 where no active material is coated.

[0202] Preferably, the uncoated portion 93 may include multiple slices 93a processed by cutting. The multiple slices 93a form multiple groups, and the height (length in the Y direction) and / or width (length in the X direction) and / or spacing of the multiple slices 93a belonging to each group may be the same. The number of multiple slices 93a belonging to each group may be increased or decreased compared to the number shown in the figures. The slices 93a may be trapezoidal in shape, and may also be deformed into quadrilaterals, parallelograms, semicircles, or semi-ellipses. Preferably, the height of the slices 93a may increase in stages from the core side towards the outer periphery. Furthermore, the uncoated portion 93' on the core side adjacent to the core side may not include slices 93a, and the height of the uncoated portion 93' on the core side may be smaller than that of other uncoated portion areas.

[0203] In one embodiment of this specification, the electrode 90 may include an insulating coating 94 covering the boundary between the active material layer 92 and the uncoated portion 93. The insulating coating 94 comprises an insulating polymer resin and may optionally include inorganic fillers. The insulating coating 94 prevents the end of the active material layer 92 from contacting an opposing active material layer through the separation membrane, thus structurally supporting the bending of the segment 93a. Therefore, when the electrode 90 is wound into an electrode assembly, preferably, at least a portion of the insulating coating 94 is exposed to the outside from the separation membrane.

[0204] Figure 11 This is a cross-sectional view of an electrode assembly 100, which is cut along the length direction Y according to an embodiment of the present invention, in which the uncoated portion of the electrode plate 90 is applied to the first electrode and the second electrode.

[0205] Reference Figure 11 Electrode assembly 100 can be manufactured according to... Figure 2 The winding process described herein. For ease of explanation, the protruding structures of the uncoated portions 72 and 73 extending beyond the separation membrane are shown in detail, while the winding structures of the first electrode, the second electrode, and the separation membrane are omitted. The downward-protruding uncoated portion 72 extends from the first electrode, and the upward-protruding uncoated portion 73 extends from the second electrode. The pattern of height variation of the aforementioned uncoated portions 72 and 73 is briefly shown.

[0206] That is, the heights of the uncoated portions 72 and 73 can vary irregularly depending on the location of the cut section. For example, if the side portion of the trapezoidal slice 93a is cut, the height of the uncoated portion in the section is lower than the height of the slice 93a. Therefore, it should be interpreted that the heights of the uncoated portions 72 and 73 shown in the accompanying drawings illustrating the cross-section of the electrode assembly 100 correspond to the average height of the uncoated portions contained in each roll.

[0207] like Figure 12 As shown, the uncoated portions 72 and 73 can be bent from the outer periphery of the electrode assembly 100 toward the core side. Figure 11 In the diagram, the bent portion 101 is indicated by a dashed box. When the uncoated portions 72 and 73 are bent, multiple adjacent slices in the radial direction overlap each other to form multiple layers, creating a bending surface 102 on the upper and lower parts of the electrode assembly 100. At this time, the uncoated portion on the core side ( Figure 10 Because of its low height, the 93' segment will not bend. The height h of the segment bent on the innermost side is the same as or smaller than the radial length r of the winding area formed by the uncoated portion 93' of the core side without segment structure. Therefore, the cavity 80 in the core of the electrode assembly 100 will not be closed by the multiple bent segments. If the cavity 80 is not closed, the electrolyte injection process is not difficult, and the electrolyte injection efficiency is improved.

[0208] According to an embodiment of the present invention, the cover plate 74a of the sealing body 74 of the secondary battery 70 is non-polarized. However, the second current collector 31 is connected to the side wall of the battery case 51, so that the outer surface 52a of the bottom surface 52 of the battery case 51 has a polarity opposite to that of the electrode terminals 50. Therefore, when multiple battery cells are connected in series and / or in parallel, wiring such as busbar connection can be performed on the upper part of the secondary battery 70 using the outer surface 52a of the bottom surface 52 of the battery case 51 and the electrode terminals 50. This increases the number of battery cells that can be installed in the same space and improves the energy density.

[0209] In one example, the anolyte may include a material with the general chemical formula A[A] x M y ]O 2+z The alkali metal compound represented by (A includes at least one element selected from Li, Na, and K; M includes at least one element 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; stoichiometric coefficients x, y, and z are selected in such a way that the compound maintains electrical neutrality).

[0210] In another example, the anode active material can be an alkali metal compound xLiM 1 O2-(1-x)Li2M 2 O3(M 1 includes at least one or more elements having an average oxidation state of 3; M 2 includes at least one or more elements having an average oxidation state of 4; 0≤x≤l).

[0211] In yet another example, the anode active material can be a lithium metal phosphate represented by the general chemical formula LiaM 1 x Fe 1-x M 2 yP 1-y M 3 zO 4-z (M 1 includes at least one or more elements selected from the group consisting of Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 includes at least one or more elements selected from the group consisting of Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 includes a halogen element optionally including F; 0

[0212] Preferably, the anode active material can include primary particles and / or secondary particles of agglomeration of the primary particles.

[0213] In one example, the cathode active material can use a carbon material, lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, etc. A metal oxide such as TiO2, SnO2, etc. having a potential of less than 2 V can also be used as the cathode active material. As the carbon material, low-crystalline carbon and / or high-crystalline carbon can be used.

[0214] The separation membrane can use a porous polymer film, for example, a porous polymer film made of an ethylene monomer polymer, a propylene monomer polymer, an ethylene / butylene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, or the like, which can be used alone, or can be used in layers. As another example, the separation membrane can use a general porous nonwoven fabric, for example, a nonwoven fabric made of a high-melting-point glass fiber, a polyethylene terephthalate fiber, or the like.

[0215] At least one side surface of the separation membrane can include a coating of inorganic particles. Also, the separation membrane itself can be made of a coating of inorganic particles. The particles that make up the coating can have a structure that binds with a binder, so that there is an interstitial volume between adjacent particles.

[0216] The inorganic particles can be made of an inorganic substance having a dielectric constant of 5 or more. As non-limiting examples, the inorganic particles can include at least one substance selected from the group consisting of Pb(Zr, Ti)O3(PZT), Pb(Mg3Nb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0217] The electrolyte can be a salt having a structure of A + B - , etc. Among them, A + includes Li + , Na + , K + , or the like, or ions made of a combination thereof. In addition, B - includes an anion selected from the group consisting of F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8- , (CF3)2PF4- - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3, CF3CF2SO3 -- , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2, SCN - , and (CF3CF2SO2)2N - any one or more anions selected from the group consisting of

[0218] The electrolyte can also be dissolved in an organic solvent. As the organic solvent, 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 (EMC), γ butyrolactone, or a mixture thereof can be used.

[0219] In the present specification, the anode active material coated on the anode plate and the cathode active material coated on the cathode plate can use active materials known in the art without any limitation.

[0220] In an embodiment of the present specification, the riveting structure of the electrode terminal 50 can be applied to a cylindrical secondary battery.

[0221] In one embodiment of the present specification, the uncoated portion of the first electrode of the electrode assembly can be cut into the same shape as the current collector plate.

[0222] In one embodiment of the present specification, the portion of the uncoated portion of the first electrode of the electrode assembly that is bent can be cut into the same shape as the current collector plate.

[0223] In one embodiment of the present specification, the secondary battery can be a cylindrical secondary battery having a shape factor ratio (a value obtained by dividing the diameter of the cylindrical secondary battery by the height, that is, a ratio of the diameter Φ with respect to the height H) of more than 0.4. Here, the shape factor indicates a value of the diameter and the height of the cylindrical secondary battery.

[0224] At present, a battery having a shape factor ratio of about 0.4 or less is used. That is, for example, a 18650 battery cell, a 21700 battery cell, or the like is used. The diameter of the 18650 battery cell is about 18 mm, the height thereof is about 65 mm, and the shape factor ratio is about 0.277. The diameter of the 21700 battery cell is about 21 mm, the height thereof is about 70 mm, and the shape factor ratio is about 0.300.

[0225] The cylindrical secondary battery according to one embodiment of the present specification can be a 46110 battery cell, a 48750 battery cell, a 48110 battery cell, a 48800 battery cell, or a 46800 battery cell. In a numerical value indicating the shape factor, the first two digits indicate the diameter of the battery cell, the next two digits indicate the height of the battery cell, and the remaining digit 0 indicates that the cross section of the battery cell is circular.

[0226] The secondary battery according to one embodiment of the present specification is a cylindrical battery cell, and can be a cylindrical secondary battery having a diameter of 46 mm, a height of 110 mm, and a shape factor ratio of 0.418.

[0227] The secondary battery according to one embodiment of the present specification is a cylindrical battery cell, and can be a cylindrical secondary battery having a diameter of 48 mm, a height of 75 mm, and a shape factor ratio of 0.640.

[0228] The secondary battery according to one embodiment of the present specification is a cylindrical battery cell, and can be a cylindrical secondary battery having a diameter of 48 mm, a height of 110 mm, and a shape factor ratio of 0.418.

[0229] The secondary battery according to one embodiment of the present specification is a cylindrical battery cell, and can be a cylindrical secondary battery having a diameter of 48 mm, a height of 80 mm, and a shape factor ratio of 0.600.

[0230] The secondary battery according to the embodiment of the present specification is a cylindrical battery cell, and can be a cylindrical secondary battery cell having a diameter of 46 mm, a height of 80 mm, and a ratio of a shape factor of 0.575.

[0231] The secondary battery according to the embodiment of the present specification can be used for manufacturing a battery pack. Figure 13 FIG. 1 is a diagram briefly showing the configuration of a battery pack according to an embodiment of the present application.

[0232] Referring to Figure 13 , the battery pack 200 according to the embodiment of the present specification includes an assembly in which the cylindrical secondary battery cells 201 are electrically connected, and a battery pack case 202 in which the assembly is accommodated. The cylindrical secondary battery cells 201 are the secondary battery cells according to the above-described embodiment. In the drawing, in order to facilitate the illustration, the illustration of components such as bus bars for electrically connecting the plurality of cylindrical secondary battery cells 201, cooling units, external terminals, and the like are omitted.

[0233] The above-described battery pack 200 can be mounted on an automobile. As an example, the automobile can be an electric automobile, a hybrid automobile, or a plug-in hybrid automobile. The automobile includes a four-wheeled automobile or a two-wheeled automobile. Figure 14 FIG. 2 is a diagram for explaining an automobile including the battery pack 200. Figure 13

[0234] Referring to Figure 14 , the automobile V according to the embodiment of the present specification includes the battery pack 200 according to the embodiment of the present specification. The automobile V operates by receiving electric power from the battery pack 200 according to the embodiment of the present application.

[0235] The above, although the present application has been described with limited embodiments and drawings, the present application is not limited to these, and those skilled in the art should be able to obtain various modifications and variations within the technical idea of the present application and the equivalent scope of the claims.​

Claims

1. A riveting structure of an electrode terminal, comprising: a battery case which is open on one side; an electrode terminal which is riveted through a through-hole formed in a bottom surface of the battery case; and a gasket which is interposed between the battery case and the electrode terminal, wherein the electrode terminal includes: a body portion which is inserted into the through-hole; an outer flange portion which is extended from one side edge of the body portion which is exposed from an outer surface of the bottom surface of the battery case along the outer surface; and an inner flange portion which is extended from the other side edge of the body portion which is exposed from an inner surface of the bottom surface of the battery case toward the inner surface, wherein the body portion and the outer flange portion have an inner cavity which is connected to each other, the inner flange portion has an opening portion which is connected to the inner cavity and is opened toward an inner side direction of the battery case, wherein an inner diameter of at least a portion of the inner cavity of the outer flange portion is larger than an inner diameter of the body portion, so that an end portion of a current collecting plate of a secondary battery is in abutment with an inner surface of the outer flange portion, wherein the end portion of the current collecting plate is formed with a protrusion so as to be riveted with the inner surface of the outer flange portion.

2. The riveting structure of the electrode terminal according to claim 1, wherein the inner diameter of at least a portion of the inner cavity of the outer flange portion is decreased as it approaches the inner side direction from the outer side of the battery case.

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

4. The riveting structure of the electrode terminal according to claim 1, wherein a maximum length of an outer surface of the outer flange portion is 10% or more and 40% or less of a maximum length of the bottom surface of the battery case.

5. A secondary battery, comprising: an electrode assembly in which first and second electrodes in a sheet shape are wound with a separator film interposed therebetween, and includes uncoated portions of the first and second electrodes which are exposed from both side end portions of the first and second electrodes; a battery case which accommodates the electrode assembly and is electrically connected to the second electrode; an electrode terminal which is riveted through a through-hole formed in a bottom surface of the battery case and is electrically connected to the first electrode, the electrode terminal including a body portion which is inserted into the through-hole, an outer flange portion which is extended from one side edge of the body portion which is exposed from an outer surface of the bottom surface of the battery case along the outer surface, and an inner flange portion which is extended from the other side edge of the body portion which is exposed from an inner surface of the bottom surface of the battery case toward the inner surface, wherein the body portion and the outer flange portion have an inner cavity which is connected to each other, and the inner flange portion has an opening portion which is connected to the inner cavity and is opened toward an inner side direction of the battery case; a first current collecting plate which is electrically connected to the uncoated portions of the first electrode; a gasket which is interposed between the electrode terminal and the through-hole; and ​ a sealing body that seals an open end of the battery case to enable insulation from the battery case, wherein at least a portion of the inner diameter of the inner cavity of the outer flange portion is larger than the inner diameter of the main body portion, such that the end portion of the first current collecting plate abuts against the inner surface of the outer flange portion, wherein the end portion of the first current collecting plate is formed with a protrusion to be riveted to the inner surface of the outer flange portion.

6. The secondary battery according to claim 5, wherein the uncoated portion of the first electrode is welded to the first current collecting plate to be electrically connected.

7. The secondary battery according to claim 5, wherein the first current collecting plate further includes a fastening portion that is sandwiched by the inner cavity of the outer flange portion and the main body portion of the electrode terminal by being inserted into the inner cavity of the outer flange portion and the main body portion of the electrode terminal through the opening portion of the inner flange portion of the electrode terminal, the fastening portion of the first current collecting plate is electrically connected to at least a portion of the inner surface of the main body portion of the electrode terminal.

8. The secondary battery according to claim 5, wherein the first current collecting plate is electrically connected to the inner surface of the inner flange portion of the electrode terminal.

9. The secondary battery according to claim 7, wherein the fastening portion of the first current collecting plate is electrically connected to at least a portion of the inner surface of the outer flange portion of the electrode terminal.

10. The secondary battery according to claim 7, wherein the outer diameter of the fastening portion of the first current collecting plate is larger than the inner diameter of the main body portion of the electrode terminal.

11. The secondary battery according to claim 7, wherein the ratio of the outer diameter of the fastening portion of the first current collecting plate to the inner diameter of the main body portion of the electrode terminal is 1:1 to 1.01:

1.

12. The secondary battery according to claim 5, wherein the ratio of the maximum outer diameter of the portion of the fastening portion of the first current collecting plate that has the protrusion to the inner diameter of the main body portion of the electrode terminal is 1.005:1 to 1.1:

1.

13. A battery pack comprising the secondary battery according to any one of claims 5 to 12.

14. An automobile comprising the battery pack according to claim 13.

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