Riveting structure of electrode terminal, cylindrical battery cell including same, battery pack, and vehicle

Abstract

The invention discloses a riveted structure of an electrode terminal, a cylindrical battery cell including the riveted structure, a battery pack, and a vehicle. The crimped structure of the electrode terminal includes: a battery can configured to have one open side; an electrode terminal riveted through a through hole formed in the bottom of the battery can; and a rivet pad interposed between the electrode terminal and the through hole. Further, the electrode terminal includes: a main body portion inserted into the through hole; an outer flange portion configured to extend along an outer surface of the bottom portion from a circumference of a side of the body portion exposed through the outer surface of the bottom portion; an inner flange portion configured to extend from a circumference of the other side of the body portion exposed through an inner surface of the bottom portion toward the inner surface of the bottom portion; and a flat portion provided to an inner side of the inner flange portion.

Description

[0001] This application is a divisional application of the invention patent application with application number 202210061735.X, invention name “Riveted structure of electrode terminal, cylindrical battery cell, battery pack and vehicle including the same” and application date January 19, 2022. Technical Field

[0002] The present disclosure relates to a riveting structure of an electrode terminal, and a cylindrical battery cell, a battery pack, and a vehicle including the same. Background Art

[0003] Secondary batteries, which are easily applicable to various product groups and have electrical characteristics such as high energy density, are commonly used not only in portable devices but also in electric vehicles (EVs), hybrid electric vehicles (HEVs), and the like driven by an electric drive source.

[0004] These secondary batteries have attracted attention as new energy sources to improve eco-friendliness and energy efficiency because they have a major advantage of significantly reducing the use of fossil fuels and a secondary advantage of not generating byproducts due to the use of energy.

[0005] Secondary batteries currently widely used in the art include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. A unit-type secondary battery cell has an operating voltage of about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack is constructed by connecting a plurality of battery cells in series. In addition, according to the required charge / discharge capacity of the battery pack, a plurality of battery cells can be connected in parallel to form a battery pack. Therefore, the number of battery cells included in the battery pack and the form of electrical connection can be set differently according to the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, as a secondary battery cell, cylindrical, rectangular and pouch-type battery cells are known. In the case of a cylindrical battery cell, a diaphragm serving as an insulator is interposed between the positive electrode and the negative electrode, and they are wound to form an electrode assembly in the form of a jelly roll, which is inserted into a battery can together with an electrolyte to construct a battery. In addition, a strip-shaped electrode connector may be connected to an uncoated portion of each of the positive electrode and the negative electrode, and the electrode connector electrically connects the electrode assembly and the electrode terminal exposed to the outside. For reference, the positive terminal is a cover plate of a sealing body that seals the opening of the battery can, and the negative terminal is a battery can.

[0007] However, according to the conventional cylindrical battery cell having such a structure, since the current is concentrated in the strip-shaped electrode joint connected to the uncoated portion of the positive electrode and / or the uncoated portion of the negative electrode, the current collection efficiency is poor due to the large resistance and large amount of heat caused by the small cross-sectional area of ​​the strip-shaped electrode joint.

[0008] Resistance and heat are not major issues for small cylindrical battery cells with a form factor of 18650 or 21700. However, when the form factor increases to apply cylindrical battery cells to electric vehicles, the cylindrical battery cells may catch fire while generating a lot of heat around the electrode joints during a fast charging process.

[0009] To solve this problem, a cylindrical battery cell (so-called jointless cylindrical battery cell) is provided in which the uncoated portion of the positive electrode and the uncoated portion of the negative electrode are designed to be positioned at the top and bottom of a jelly-roll type electrode assembly, respectively, and the current collecting plates are welded to the uncoated portions to improve the current collecting efficiency.

[0010] Figures 1 to 3 is a view showing a process of manufacturing a jointless cylindrical battery cell. Figure 1 The structure of the electrode plate is shown. Figure 2 The process of winding the electrode plate is shown. Figure 3 The process of welding the current collecting plate to the curved surface of the uncoated portion is shown. Figure 4 is a cross-sectional view taken along the longitudinal direction (Y) showing a tabless cylindrical battery cell.

[0011] Reference Figures 1 to 4 , the positive electrode plate 10 and the negative electrode plate 11 have a structure in which a sheet-shaped current collector 20 is coated with an active material 21 , and includes an uncoated portion 22 at one long side in the winding direction X.

[0012] like Figure 2 As shown, the electrode assembly A is manufactured by sequentially stacking the positive electrode plate 10 and the negative electrode plate 11 with the separator 12 of two sheets and then winding them in one direction X. At this time, the uncoated portions of the positive electrode plate 10 and the negative electrode plate 11 are arranged in opposite directions.

[0013] After the winding process, the uncoated portion 10a of the positive electrode plate 10 and the uncoated portion 11a of the negative electrode plate 11 are bent toward the core. After that, the current collecting plates 30, 31 are welded and coupled to the uncoated portions 10a, 11a, respectively.

[0014] The electrode tabs are not separately connected to the positive electrode uncoated portion 10a and the negative electrode uncoated portion 11a, the current collecting plates 30, 31 are connected to the external electrode terminals, and the current path is along the winding axis direction of the electrode assembly A (see Figure 3 The arrow in the figure has a large cross-sectional area, which has the advantage of reducing the resistance of the battery cell. This is because the resistance is inversely proportional to the cross-sectional area of ​​the path through which the current flows.

[0015] However, as the form factor of the cylindrical battery cell increases and the magnitude of the charging current during fast charging increases, thermal issues also re-emerge in the tabless cylindrical battery cell.

[0016] Specifically, Figure 4 As shown, a conventional jointless cylindrical battery cell 40 includes a battery can 41 and a sealing body 42. The sealing body 42 includes a cover plate 42a, a sealing gasket 42b and a connecting plate 42c. The sealing gasket 42b surrounds the edge of the cover plate 42a and is fixed by a crimping portion 43. In addition, the electrode assembly A is fixed in the battery can 41 by a crimping portion 44 to prevent vertical movement.

[0017] Typically, the positive terminal is the cover plate 42a of the sealing body 42, and the negative terminal is the battery can 41. Therefore, the current collecting plate 30 coupled to the uncoated portion 10a of the positive electrode plate 10 is electrically connected to the connection plate 42c attached to the cover plate 42a through a lead 45 in the form of a strip. In addition, the current collecting plate 31 coupled to the uncoated portion 11a of the negative electrode plate 11 is electrically connected to the bottom of the battery can 41. The insulator 46 covers the current collecting plate 30 to prevent the uncoated portion 10a of the battery can 41 and the positive electrode plate 10 having different polarities from contacting each other and causing a short circuit.

[0018] When the current collecting plate 30 is connected to the connecting plate 42c, a lead 45 in the form of a strip is used. The lead 45 is attached to the current collecting plate 30 separately or is manufactured integrally with the current collecting plate 30. However, since the lead 45 is in the form of a thin strip, its cross-sectional area is small, so a large amount of heat is generated when the fast charging current flows. In addition, the excessive heat generated from the lead 45 is transferred to the electrode assembly A to shrink the separator 12, which may cause an internal short circuit, which is the main cause of thermal runaway.

[0019] The lead 45 also occupies a large amount of installation space within the battery can 41. Therefore, the cylindrical battery cell 40 including the lead 45 has low space efficiency, and thus has a limitation in increasing energy density.

[0020] In addition, in order to connect the conventional jointless cylindrical battery cells 40 in series and / or in parallel, it is necessary to connect the bus bar parts to the cover plate 42a of the sealing body 42 and the bottom surface of the battery can 41, which reduces the space efficiency. The battery pack mounted on the electric vehicle includes hundreds of cylindrical battery cells 40. Therefore, the inefficiency of the electrical wiring causes considerable inconvenience in the assembly process of the electric vehicle and the maintenance of the battery pack. Summary of the invention

[0021] Technical issues

[0022] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure aims to reduce the internal resistance of a cylindrical battery cell and increase the energy density by improving the electrode terminal structure of the cylindrical battery cell to increase the space efficiency in a battery can.

[0023] The present disclosure also aims to improve the electrode terminal structure of a cylindrical battery cell to solve the internal heating problem caused during fast charging by expanding the cross-sectional area of ​​a current path.

[0024] The present disclosure also aims to provide a cylindrical battery cell having an improved structure that allows electrical wiring for series and / or parallel connection of the cylindrical battery cells to be performed on one side of the cylindrical battery cell.

[0025] The present disclosure also aims to provide a battery pack manufactured using a cylindrical battery cell having an improved structure and a vehicle including the battery pack.

[0026] However, the technical objects to be solved by the present disclosure are not limited to the above, and other objects not mentioned herein will be clearly understood by those skilled in the art from the following disclosure.

[0027] Technical Solution

[0028] In one aspect of the present disclosure, a riveting structure of an electrode terminal is provided, the riveting structure comprising: a battery can, the battery can being configured to have an open side; an electrode terminal, the electrode terminal being riveted through a perforation formed in the bottom of the battery can; and a rivet gasket, the rivet gasket being inserted between the electrode terminal and the perforation, wherein the electrode terminal comprises: a main body portion, the main body portion being inserted into the perforation; an outer flange portion, the outer flange portion being configured to extend along the outer surface of the bottom of the battery can from a circumference of one side of the main body portion exposed through the outer surface of the bottom of the battery can; an inner flange portion, the inner flange portion being configured to extend toward the inner surface of the bottom of the battery can from a circumference of the other side of the main body portion exposed through the inner surface of the bottom of the battery can; and a flat portion, the flat portion being arranged to the inner side of the inner flange portion.

[0029] Preferably, the flat portion may be parallel to the inner surface of the bottom.

[0030] Preferably, an angle between the inner flange portion and the inner surface of the bottom may be 0° to 60°.

[0031] Preferably, a recess may be provided between the inner flange portion and the flat portion.

[0032] In one embodiment, the recess may have a cross-sectional structure of an asymmetric groove.

[0033] In another embodiment, the asymmetric groove may include a side wall of the flat portion and an inclined surface of an end portion of the inner flange portion connected to the side wall.

[0034] In yet another embodiment, the side wall may be perpendicular to the inner surface of the bottom.

[0035] In yet another embodiment, the side wall may be inclined toward the flat portion.

[0036] Preferably, the inner flange portion may have a thickness which gradually decreases as being farther away from the main body portion.

[0037] Preferably, the rivet pad may include: an outer gasket, which is inserted between the outer flange portion and the outer surface of the bottom, and an inner gasket, which is inserted between the inner flange portion and the inner surface of the bottom, and the inner gasket may have different thicknesses depending on its position.

[0038] In one embodiment, a region of the inner gasket interposed between an inner edge of the through hole connected to the inner surface of the bottom and the inner flange portion may have a relatively smaller thickness than other regions.

[0039] In another embodiment, a region of the inner gasket interposed between the through hole and the body portion may have a thickness gradually decreasing as being farther away from the outer flange portion.

[0040] In still another embodiment, a region of the inner gasket interposed between the inner surface of the bottom portion and a region near an end of the inner flange portion may have a minimum thickness.

[0041] In yet another embodiment, the inner edge of the perforation may include a facing surface facing the inner flange portion.

[0042] In yet another embodiment, the inner gasket may be configured to extend longer than the inner flange portion such that an end portion of the inner gasket is exposed.

[0043] In still another embodiment, a height of the flat portion may be equal to or greater than a height of an end portion of the inner gasket based on the inner surface of the bottom.

[0044] In still another embodiment, a height of the flat portion may be equal to or greater than a height of the inner flange portion based on the inner surface of the bottom portion.

[0045] In still another embodiment, a height of the inner flange portion may be greater than a height of an end portion of the inner gasket based on the inner surface of the bottom portion.

[0046] Preferably, a height of the inner flange portion may be 0.5 mm to 3.0 mm based on the inner surface of the bottom of the battery can.

[0047] Preferably, a height of the electrode terminal extending from a lower surface of the outer flange portion to a surface of the flat portion may be 4 mm to 7 mm.

[0048] Preferably, a height of the outer flange portion may be 0.8 mm or more based on the outer surface of the bottom of the battery can.

[0049] Preferably, at least a portion of the outer gasket may be exposed outside the outer flange portion, and an exposed width of the outer gasket measured in a direction parallel to the outer surface of the bottom of the battery can may be 0.1 mm to 1 mm.

[0050] Preferably, a radius from the center of the body portion to the edge of the outer flange portion may be 10% to 70% of a radius of the bottom of the battery can.

[0051] Preferably, a radius from a center of the body portion to an edge of the flat portion may be 4% to 30% of a radius of the bottom portion.

[0052] Preferably, when a ratio of a thickness change at a maximum compression point compared to a thickness of the gasket before compression is defined as a compression ratio, the compression ratio of the inner gasket may be 30% to 90%.

[0053] More preferably, the inner gasket may include polybutylene terephthalate, polyvinyl fluoride, or polypropylene, and a compression ratio of the inner gasket may be 50% to 90%.

[0054] In another aspect of the present disclosure, a cylindrical battery cell is provided, the cylindrical battery cell comprising: an electrode assembly, in which a first electrode plate and a second electrode plate having a sheet shape are wound with a separator sandwiched therebetween, the electrode assembly having an uncoated portion of the first electrode plate and an uncoated portion of the second electrode plate, the uncoated portion of the first electrode plate and the uncoated portion of the second electrode plate being configured to extend from both ends of the electrode assembly and be exposed to the outside of the separator; a cylindrical battery can, the cylindrical battery can being configured to accommodate the electrode assembly and electrically connected to the first electrode plate; an electrode terminal, the electrode terminal being riveted and electrically connected to the second electrode plate through a perforation formed in the bottom of the battery can; the electrode terminal comprising: a main body portion , the main body portion is inserted into the perforation; an outer flange portion, the outer flange portion is configured to extend from the circumference of one side of the main body portion exposed through the outer surface of the bottom of the battery can along the outer surface of the bottom of the battery can; an inner flange portion, the inner flange portion is configured to extend from the circumference of the other side of the main body portion exposed through the inner surface of the bottom of the battery can toward the inner surface of the bottom of the battery can; and a flat portion, the flat portion is arranged to the inner side of the inner flange portion, the cylindrical battery cell also includes: a rivet gasket, the rivet gasket is inserted between the electrode terminal and the perforation; and a sealing body, the sealing body is configured to seal the open end of the battery can so as to be insulated from the battery can.

[0055] In one embodiment, the battery can may include a pressed edge portion, which is formed in an area adjacent to the open end and is pressed into the battery can, and the seal may include a non-polar cover plate and a sealing gasket inserted between the edge of the cover plate and the open end of the battery can.

[0056] In another embodiment, the battery can may further include a curling portion extending and bending to the inside of the battery can and configured to surround the edge of the cover plate and fix the edge of the cover plate and the sealing gasket together.

[0057] Preferably, the cover plate may include a venting recess, and when the pressure inside the battery can exceeds a threshold value, the venting recess is broken.

[0058] Preferably, when the pressure inside the battery can is 15 kgf / cm 2 Up to 35kgf / cm 2 When within the range of , the exhaust notch may rupture.

[0059] In another embodiment, the cylindrical battery cell according to the present disclosure may further include a first current collecting plate connected to the uncoated portion of the first electrode plate, and at least a portion of the edge of the first current collecting plate that is not in contact with the uncoated portion of the first electrode plate may be inserted between the pressing portion and the sealing gasket and fixed by the curling portion.

[0060] Preferably, at least a portion of the edge of the first current collecting plate may be fixed to an inner circumference of the pressing portion adjacent to the curling portion by welding.

[0061] In yet another embodiment, the cylindrical battery cell according to the present disclosure may further include a second current collecting plate coupled to the uncoated portion of the second electrode plate, and at least a portion of the second current collecting plate may be coupled to the flat portion of the electrode terminal.

[0062] Preferably, the second current collecting plate and the flat portion of the electrode terminal may be coupled by welding, and a tension of a welding portion between the second current collecting plate and the flat portion of the electrode terminal may be 2 kgf or more.

[0063] Preferably, a converted diameter of the welding pattern exposed on the surface of the second current collecting plate may be 2 mm or more.

[0064] Preferably, a diameter of the flat portion of the electrode terminal may be 3 mm to 14 mm.

[0065] Preferably, a ratio of an area of ​​the welding pattern exposed on the surface of the second current collecting plate to an area of ​​the flat portion of the electrode terminal may be 2.04% to 44.4%.

[0066] In yet another embodiment, the cylindrical battery cell according to the present disclosure may further include an insulator interposed between the second current collecting plate and the inner circumference of the bottom of the battery can and between the inner circumference of the side wall of the battery can and the electrode assembly.

[0067] Preferably, the insulator may have a welding hole formed to expose the flat portion of the electrode terminal toward the second current collecting plate and to cover a surface of the second current collecting plate and an edge of one side of the electrode assembly.

[0068] Preferably, a height from the inner surface of the bottom of the battery can to the flat portion of the electrode terminal may be equal to or less than a thickness of the insulator.

[0069] Preferably, the rivet gasket may include: an outer gasket, which is inserted between the outer flange portion and the outer surface of the bottom of the battery can; and an inner gasket, which is inserted between the inner flange portion and the inner surface of the bottom of the battery can.

[0070] Preferably, an end portion of the inner gasket may be exposed to the outside of the inner flange portion.

[0071] In yet another embodiment, the welding hole may expose the flat portion and the inner flange portion of the electrode terminal.

[0072] In yet another embodiment, the welding hole may expose the flat portion, the inner flange portion, and the inner gasket of the electrode terminal.

[0073] In yet another embodiment, in the cylindrical battery cell according to the present disclosure, a first bus bar terminal may be electrically coupled to a surface of the electrode terminal, and a second bus bar terminal may be electrically coupled to the outer surface of the bottom of the battery can.

[0074] Preferably, the first bus bar terminal may overlap with the electrode terminal in a plane to form a first overlapping area, and the second bus bar terminal may overlap with the outer surface of the bottom of the battery can to form a second overlapping area, and the diameter of the electrode terminal and the width of the outer surface of the bottom of the battery can may satisfy the following relational expression,

[0075] W1≤E1≤D-2R d -2G-2W2

[0076] E2=0.5*(D-2R d -2G-E1)

[0077] (E1: diameter of the electrode terminal, E2: width of an exposed surface parallel to the surface of the electrode terminal in the outer surface of the bottom of the battery can, D: outer diameter of the battery can, R d : the width of the circular area at the edge of the battery can measured on a plane, G: the exposed width of the outer gasket through the edge of the electrode terminal, W1: the maximum value among the distances between any two points selected in the edge of the first overlapping area, W2: the maximum value among the distances between two points where multiple straight lines passing through the center of the electrode terminal intersect with the edge of the second overlapping area).

[0078] In yet another embodiment, a shape factor ratio obtained by dividing the diameter of the cylindrical battery cell by the height may be greater than 0.4.

[0079] In another aspect of the present disclosure, a battery pack including a plurality of cylindrical battery cells as described above is also provided.

[0080] Preferably, the plurality of cylindrical battery cells may be arranged in a predetermined number of columns, and the electrode terminal and the outer surface of the bottom of the battery can of each cylindrical battery cell may be disposed to face upward.

[0081] Preferably, the battery pack according to the present disclosure may include: a plurality of bus bars, which are configured to connect the plurality of cylindrical battery cells in series and in parallel, the plurality of bus bars may be arranged above the plurality of cylindrical battery cells, and each bus bar may include: a main body portion, which is configured to extend between electrode terminals of adjacent cylindrical battery cells; a plurality of first bus bar terminals, which are respectively configured to extend from the main body portion in a one side direction and electrically connected to the electrode terminals of the cylindrical battery cells located in the one side direction; and a plurality of second bus bar terminals, which are respectively configured to extend from the main body portion in another side direction and electrically connected to the outer surface of the bottom of the battery can of the cylindrical battery cells located in the another side direction.

[0082] Preferably, an AC resistance of the cylindrical battery cell measured between the electrode terminal and the outer surface of the bottom of the battery can may be 4 milliohms (mΩ) or less.

[0083] In another aspect of the present disclosure, a vehicle including the battery pack as described above is also provided.

[0084] Beneficial Effects

[0085] According to an embodiment of the present disclosure, by improving the electrode terminal structure of a cylindrical battery cell to increase space efficiency in a battery can, the internal resistance of the cylindrical battery cell may be reduced and the energy density may be increased.

[0086] According to another embodiment of the present disclosure, by improving the electrode terminal structure of a cylindrical battery cell to expand the cross-sectional area of ​​a current path, the internal heating problem caused during fast charging may be solved.

[0087] According to still another embodiment of the present disclosure, electrical wiring for series and / or parallel connection of cylindrical battery cells may be performed on one side of the cylindrical battery cells.

[0088] According to still another embodiment of the present disclosure, a battery pack manufactured using a cylindrical battery cell having an improved structure and a vehicle including the battery pack may be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not interpreted as being limited to the accompanying drawings.

[0090] Figure 1 is a plan view showing the structure of an electrode plate for a conventional tabless cylindrical battery cell.

[0091] Figure 2 is a diagram showing a process of winding an electrode assembly included in a conventional tabless cylindrical battery cell.

[0092] Figure 3 It is shown in Figure 2 Illustration of the process of welding a current collecting plate to a curved surface of an uncoated portion in an electrode assembly.

[0093] Figure 4 is a cross-sectional view showing a conventional tabless cylindrical battery cell taken along the longitudinal direction (Y).

[0094] Figure 5 is a cross-sectional view illustrating a rivet structure of an electrode terminal according to an embodiment of the present disclosure.

[0095] Figure 6a It is shown by Figure 5 An enlarged cross-sectional view of the portion indicated by the dotted circle.

[0096] Figure 6b is a partially enlarged cross-sectional view showing a rivet structure of an electrode terminal according to another embodiment of the present disclosure.

[0097] Figure 7a 2 is a cross-sectional view showing a cylindrical battery cell according to an embodiment of the present disclosure, taken along a longitudinal direction (Y).

[0098] Figure 7b is a cross-sectional view taken along a longitudinal direction (Y) showing a cylindrical battery cell according to another embodiment of the present disclosure.

[0099] Figure 8 is a plan view exemplarily showing an electrode plate structure according to a preferred embodiment of the present disclosure.

[0100] Fig. 9 is a cross-sectional view taken along a longitudinal direction (Y) showing an electrode assembly in which a segment structure of an uncoated portion of an electrode plate is applied to a first electrode plate and a second electrode plate according to an embodiment of the present disclosure.

[0101] Fig.10a is a cross-sectional view taken along a longitudinal direction (Y) showing an electrode assembly in which an uncoated portion is bent according to an embodiment of the present disclosure.

[0102] Fig.10b is a perspective view illustrating an electrode assembly in which an uncoated portion is bent according to an embodiment of the present disclosure.

[0103] Fig.11 is a top plan view showing that a plurality of cylindrical battery cells are connected in series and in parallel using bus bars according to an embodiment of the present disclosure.

[0104] Fig.12a yes Fig.11 A partial enlarged view of .

[0105] Figure 12b and Fig.12c is a diagram exemplarily showing parameters for defining a diameter of an electrode terminal and an exposed width of an outer surface of a bottom of a battery can according to an embodiment of the present disclosure.

[0106] Fig.13 is a diagram showing a schematic configuration of a battery pack including a cylindrical battery cell according to an embodiment of the present disclosure.

[0107] Fig.14 is a diagram showing a schematic configuration of a vehicle including a battery pack according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0108] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but are interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure based on the principle of allowing the inventor to appropriately define the terms for the best interpretation.

[0109] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes only, and are not intended to limit the scope of the present disclosure, and it should be appreciated that other equivalents and modifications may be made thereto without departing from the scope of the present disclosure.

[0110] In addition, to help understand the present invention, in the drawings, some components may not be drawn to scale, but their sizes may be exaggerated. Moreover, in different embodiments, the same reference numerals may be assigned to the same components.

[0111] When explaining that two objects are the same, this means that the objects are "substantially the same". Thus, substantially the same objects may include deviations that are considered low in the art, for example, within 5%. In addition, when explaining that certain parameters are uniform in a predetermined area, this may mean that the parameters are uniform in terms of average value.

[0112] The cylindrical battery cell according to an embodiment of the present disclosure may include an electrode terminal riveted to the bottom of a battery can.

[0113] Figure 5 is a cross-sectional view showing a riveting structure of an electrode terminal 50 according to an embodiment of the present disclosure, Figure 6a It is shown by Figure 5 An enlarged cross-sectional view of the portion indicated by the dotted circle.

[0114] Reference Figure 5 and Figure 6a According to the embodiment, the riveting structure of the electrode terminal 50 may include a cylindrical battery can 51 having an open side, the electrode terminal 50 riveted through a through hole 53 formed in the bottom 52 of the battery can 51, and a rivet gasket 54 inserted between the electrode terminal 50 and the through hole 53.

[0115] The battery can 51 is made of a conductive metal material. In one example, the battery can 51 may be made of steel, aluminum, stainless steel, etc., but the present disclosure is not limited thereto. The inner and outer surfaces of the battery can 51 may be coated with a Ni plating layer.

[0116] The electrode terminal 50 is made of a conductive metal material. In one example, the electrode terminal 50 may be made of steel, aluminum, stainless steel, etc., but the present disclosure is not limited thereto. The electrode terminal 50 may be made of a 10 series aluminum alloy that is easy to rivet and has low resistance.

[0117] The rivet washer 54 may be made of a polymer resin having insulation and elasticity. In one example, the rivet washer 54 may be made of polypropylene, polybutylene terephthalate, polyvinyl fluoride, etc., but the present disclosure is not limited thereto.

[0118] Preferably, the electrode terminal 50 may include a main body portion 50a inserted into the perforation 53, an outer flange portion 50b extending along the outer surface 52a from the circumference of one side of the main body portion 50a exposed through the outer surface 52a of the bottom 52 of the battery can 51, an inner flange portion 50c extending toward the inner surface 52b from the circumference of the other side of the main body portion 50a exposed through the inner surface 52b of the bottom 52 of the battery can 51, and a flat portion 50d arranged inside the inner flange portion 50c.

[0119] Preferably, the flat portion 50d and the inner surface 52b of the bottom 52 of the battery can 51 may be parallel to each other. Here, the term "parallel" means substantially parallel when observed with the naked eye.

[0120] According to one embodiment, the angle (θ) between the inner flange portion 50c and the inner surface 52b of the bottom 52 of the battery can 51 may be 0° to 60°. The size of the angle is determined by the caulking strength when the electrode terminal 50 is installed in the perforation 53 of the battery can 51 by the caulking method. In one example, as the caulking strength increases, the angle (θ) may be reduced to 0°. If the angle exceeds 60°, the sealing effect of the rivet gasket 54 may be deteriorated.

[0121] According to another embodiment, the recess 55 may be disposed between the inner flange portion 50c and the flat portion 50d. The recess 55 may have a cross-sectional structure of an asymmetric groove. In one example, the asymmetric groove may have an approximately V-shaped shape. The asymmetric groove may include a side wall 55a of the flat portion 50d and an inclined surface 55b of the inner flange portion 50c connected to the end of the side wall 55a. The side wall 55a may be substantially perpendicular to the inner surface 52b of the bottom 52 of the battery can 51. The term "vertical" means that it is substantially vertical when observed with the naked eye. As will be explained later, the side wall 55a may be inclined toward the flat portion 50d. When the electrode terminal 50 is installed in the perforation 53 of the battery can 51 by the caulking method, the recess 55 is formed by the shape of the caulking fixture.

[0122] Preferably, the thickness of the inner flange portion 50 c may gradually decrease as being farther away from the body portion 50 a of the electrode terminal 50 .

[0123] According to another embodiment, the rivet gasket 54 may include an outer gasket 54a interposed between the outer flange portion 50b and the outer surface 52a of the bottom 52 of the battery can 51, and an inner gasket 54b interposed between the inner flange portion 50c and the inner surface 52b of the bottom 52 of the battery can 51. Preferably, the outer gasket 54a and the inner gasket 54b are separated based on the outer surface 52a of the bottom of the battery can 51.

[0124] The outer gasket 54a and the inner gasket 54b may have different thicknesses depending on their positions. Preferably, the region of the inner gasket 54b interposed between the inner flange portion 50c and the inner edge 56 of the perforation 53 connected to the inner surface 52b of the bottom 52 of the battery can 51 may have a relatively small thickness. Preferably, the minimum thickness point may exist in the gasket region interposed between the inner edge 56 of the perforation 53 and the inner flange portion 50c. In addition, the inner edge 56 of the perforation 53 may include a facing surface 57 facing the inner flange portion 50c.

[0125] At the same time, the top and bottom of the inner wall of the perforation 53 perpendicular to the bottom 52 of the battery can 51 are chamfered (cut corners) to form a tapered surface toward the electrode terminal 50. However, the top and / or bottom of the inner wall of the perforation 53 may be transformed into a smoothly curved surface having a curvature. In this case, the stress applied to the gasket 54 near the top and / or bottom of the inner wall of the perforation 53 may be better relieved.

[0126] Preferably, the inner gasket 54 b may extend longer than the inner flange portion 50 c while forming an angle of 0° to 60° with the inner surface 52 b of the bottom 52 of the battery can 51 .

[0127] In another embodiment, the height (H1) of the flat portion 50d may be equal to or greater than the height (H2) of the end of the inner gasket 54b based on the inner surface 52b of the bottom 52 of the battery can 51. In addition, the height (H1) of the flat portion 50d may be equal to or greater than the height (H3) of the end of the inner flange portion 50c based on the inner surface 52b of the bottom 52 of the battery can 51. Here, the height H2 is the maximum height of the end of the inner gasket 54b measured based on the inner surface 52b. In addition, the height H3 is the maximum height of the end of the inner flange portion 50c measured based on the inner surface 52b.

[0128] If the height parameters H1, H2, H3 satisfy the conditions, the inner flange portion 50c and the inner gasket 54b can be prevented from interfering with other components.

[0129] Preferably, the height (H3) of the inner flange portion 50c may be 0.5 mm to 3.0 mm. If the height (H3) of the inner flange portion 50c is less than 0.5 mm, sufficient sealing performance cannot be ensured. In addition, if the height (H3) of the inner flange portion 50c exceeds 3 mm, the internal space of the battery can 51 that can be occupied by the electrode assembly is reduced.

[0130] Preferably, the height (H4) of the electrode terminal 50 may be 1.5 mm to 7 mm. The height (H4) of the electrode terminal 50 corresponds to the distance from the lower surface of the outer flange portion 50 b to the flat portion 50 d. If the height (H4) of the electrode terminal 50 is less than 1.5 mm, it is difficult to increase the height of the inner flange portion 50 c to a degree that can ensure the sealing performance due to the thickness of the bottom 52 of the battery can 51. For reference, the thickness of the bottom 52 of the battery can 51 is about 0.5 mm to 1 mm. In addition, if the height (H4) of the electrode terminal 50 exceeds 7 mm, the internal space of the battery can 51 that can be occupied by the electrode assembly is reduced, and the height of the battery cell is increased, so the energy density per unit volume is also reduced. When H3 and H4 meet the above numerical ranges, the sealing performance of the electrode terminal 50 can be fully ensured without reducing the space inside the battery can 51.

[0131] In another embodiment, based on the outer surface 52a of the bottom 54 of the battery can 51, the height (H5) of the outer flange portion 50b may be 0.8mm or more. If the height (H5) of the outer flange portion 50b is less than 0.8mm, the outer flange portion 50b may be deformed when the electrode terminal 50 is riveted. Considering the insulation and sealing properties, the thickness of the outer gasket 54a is 0.3mm or more. Considering the thickness of the outer gasket 54a, if the height of the outer flange portion 50b is less than 0.8mm, the outer flange portion 50b is thinned to a level that is difficult to ensure sufficient mechanical rigidity. In particular, when the electrode terminal 50 is made of aluminum, this is more serious. At the same time, the height of the outer flange portion 50b can be appropriately set in consideration of the space margin of the upper part of the battery cell. In one example, the height of the outer flange portion 50b can be set to 2mm or less, or 3mm or less, or 4mm or less, but the present disclosure is not limited thereto.

[0132] In yet another embodiment, at least a portion of the outer gasket 54a may be exposed to the outside of the outer flange portion 50b of the electrode terminal 50. The outer gasket 54a is to insulate the electrode terminal 50 and the outer surface 52a having the opposite polarity to the electrode terminal 50 from each other. In order to electrically insulate the electrode terminal 50 and the outer surface 52a, the exposed width (G) of the outer gasket 54a may be 0.1mm to 1mm. If the exposed width (G) is less than 0.1mm, the electrical insulation of the electrode terminal 50 and the outer surface 42a on the plane may be destroyed when a high C rate charge / discharge of 300A or more is performed. In addition, if the exposed width (G) exceeds 1mm, the electrical insulation effect will not be further increased, but the area of ​​the outer surface 42a used as the area of ​​the negative electrode is reduced, thereby reducing the contact area of ​​the components (e.g., busbars) used for electrical connection.

[0133] In yet another embodiment, the diameter of the flat portion 50d of the electrode terminal 50 may be determined in consideration of the welding strength between the current collecting plate and the flat portion 50d. The tension of the welded portion between the flat portion 50d and the current collecting plate may be at least 2kgf or more, or 5kgf or more, or 6kgf or more, or 7kgf or more, or 8kgf or more, or 9kgf or more, or 10kgf or more. It is desirable to increase the tension of the welded portion as much as possible within the allowable range by selecting the welding method in the best manner.

[0134] In order to satisfy the tension condition of the welded portion, the diameter of the weld pattern formed on the flat portion 50d may be at least 2 mm. When the area (S) of the weld bead present on the surface of the welded portion is converted into the area of ​​a circle (πr 2 ), the diameter of the weld pattern can be defined as the converted diameter of the corresponding circle (2*(S / π) 0.5 ).

[0135] The flat portion 50d of the electrode terminal 50 corresponds to a weldable area. The diameter of the weldable area may be 3 mm to 14 mm. If the diameter of the weldable area is less than 3 mm, it is difficult to ensure a welding pattern having a diameter of 2 mm or more. In particular, when laser welding is used to form a welding pattern, it is difficult to ensure a welding pattern having a diameter of 2 mm or more due to laser beam interference. If the diameter of the weldable area exceeds 14 mm, the diameter of the outer flange portion 50b of the electrode terminal 50 becomes too large, and it is difficult to fully ensure that the area of ​​the outer surface 52a of the bottom 52 of the battery can is used as a negative electrode area.

[0136] Considering the diameter condition of the welding pattern and the diameter condition of the weldable area, the ratio of the area of ​​the welding pattern to the area of ​​the weldable area required to ensure the tension of the welding portion of at least 2 kgf or more is preferably 2.04%

[0137] (π1 2 / π7 2 ) to 44.4%(π1 2 / π1.5 2 ).

[0138] In another embodiment, the radius ( R1 ) from the center of the body portion 50 a to the edge of the outer flange portion 50 b may be 10% to 70% of the radius ( R2 ) of the bottom 52 of the battery can 51 .

[0139] If R1 is small, there is insufficient welding space when wiring a component (bus bar) for electrical connection of the electrode terminal 50. In addition, if R1 is large, the welding space is reduced when welding a component (bus bar) for electrical connection to the outer surface 52a of the bottom 52 of the battery can 51 (except the electrode terminal 50).

[0140] If the ratio R1 / R2 is adjusted between 10% and 70%, a welding space for the electrode terminal 50 and the outer surface 52 a of the bottom 52 of the battery can 51 can be appropriately ensured.

[0141] In addition, a radius ( R3 ) from the center of the body portion 50 a of the electrode terminal 50 to the edge of the flat portion 50 d may be 4% to 30% of the radius ( R2 ) of the bottom 52 of the battery can 51 .

[0142] If R3 is small, the welding space becomes insufficient when the current collecting plate is welded to the flat portion 50d of the electrode terminal 50, and the welding area of ​​the electrode terminal 50 is reduced, thereby increasing the contact resistance. In addition, R3 must be smaller than R1. If R3 becomes larger, the thickness of the inner flange portion 50c becomes thinner, and the strength of the inner flange portion 50c of the compression rivet gasket 54 becomes weak, which deteriorates the sealing ability of the rivet gasket 54.

[0143] If R3 / R2 is adjusted between 4% and 30%, the welding process can be easily performed by sufficiently ensuring the welding area between the flat portion 50d of the electrode terminal 50 and the current collecting plate, and the contact resistance of the welding area can also be reduced and the sealing ability of the rivet gasket 54 can be prevented from being deteriorated.

[0144] According to an embodiment of the present disclosure, the riveted structure of the electrode terminal 50 can be formed using a caulking fixture that moves up and down. First, a preform (not shown) of the electrode terminal 50 is inserted into a perforation 53 formed in the bottom 52 of the battery can 51 by inserting a rivet gasket 54. The preform refers to the electrode terminal before riveting.

[0145] Next, a caulking jig is inserted into the inner space of the battery can 51. The caulking jig has grooves and protrusions corresponding to the final shape of the electrode terminal 50 on a surface opposite to the preform, so as to form the electrode terminal 50 by riveting the preform.

[0146] Next, the caulking jig is moved downward to perform press forming on the upper portion of the preform, thereby transforming the preform into the riveted electrode terminal 50 .

[0147] While the preform is being pressed by the caulking jig, the outer gasket 54a inserted between the outer flange portion 50b and the outer surface 52a of the bottom 52 of the battery can 51 is elastically compressed, so that its thickness is reduced. In addition, since the area of ​​the inner gasket 54b inserted between the inner edge 56 of the perforation 53 and the preform is elastically compressed by the inner flange portion 50c, the thickness of this area is further reduced than other areas. In particular, the area where the thickness of the inner gasket 54b is significantly reduced is composed of Figure 6a Therefore, the sealing and airtightness between the riveted electrode terminal 50 and the battery can 51 are significantly improved.

[0148] Preferably, the rivet gasket 54 is sufficiently compressed to ensure the desired seal strength without being physically damaged during the riveting process of the preforms.

[0149] Preferably, the compression ratio of the rivet gasket 54 may be 30% to 90%. The minimum compression ratio (30%) corresponds to the lowest level of compression ratio that ensures the sealing performance of the electrode terminal 50. The maximum compression ratio (90%) corresponds to the highest level of compression ratio that can be achieved without physically damaging the rivet gasket 54.

[0150] In one example, when the rivet washer 54 is made of polybutylene terephthalate, it is preferred that the rivet washer 54 has a compression ratio of 50% or more at a point where the rivet washer 54 is compressed to a minimum thickness. The compression ratio is a ratio of a thickness change before and after compression relative to a thickness before compression.

[0151] Preferably, a compression ratio is determined for the inner gasket 54b. That is, the compression ratio can be defined as the ratio of the thickness change at the maximum compression point compared to the thickness of the inner gasket 54b before compression. This also applies hereinafter. The thickness of the inner gasket 54b before compression can be uniform, and the maximum compression point can exist near the inner edge 56.

[0152] In another example, when the rivet washer 54 is made of polyvinyl fluoride, it is preferred that the rivet washer 54 has a compression ratio of 60% or more at a point where the rivet washer 54 is compressed to a minimum thickness. Preferably, the compression ratio for the inner washer 54b is determined.

[0153] In yet another example, when the rivet washer 54 is made of polypropylene, it is preferred that the rivet washer 54 has a compression ratio of 60% or more at a point where the rivet washer 54 is compressed to a minimum thickness. Preferably, the compression ratio for the inner washer 54b is determined.

[0154] Preferably, by vertically moving the caulking jig at least twice, press forming can be performed on the upper portion of the preform in multiple stages. That is, the preform can be deformed several times by performing press forming in multiple stages. At this time, the pressure applied to the caulking jig can be gradually increased. In this way, the stress applied to the preform is dispersed several times, thereby preventing the rivet gasket 54 from being damaged during the caulking process. In particular, when the area of ​​the inner gasket 54b inserted between the inner edge 56 of the perforation 53 and the preform is significantly compressed by the inner flange portion 50c, the damage to the gasket is minimized by performing press forming in multiple stages.

[0155] After the preform is completely press-formed using the caulking jig, if the caulking jig is separated from the battery can 51, the riveted structure of the electrode terminal 50 according to the embodiment of the present disclosure may be obtained, such as Figure 6a shown.

[0156] According to the above-described embodiment, the caulking jig performs press-forming on the upper portion of the preform by vertically moving inside the battery can 51 , and in some cases, a rotary jig used in the related art may be used to perform press-forming on the preform.

[0157] However, the rotating jig rotates in a state of being inclined at a predetermined angle relative to the central axis of the battery can 51. Therefore, a rotating jig having a large rotation radius may interfere with the inner wall of the battery can 51. In addition, if the depth of the battery can 51 is large, the length of the rotating jig also increases. In this case, as the rotation radius of the end of the rotating jig increases, press forming may not be properly performed on the preform. Therefore, it is more effective to perform press forming using a caulking jig rather than using a rotating jig.

[0158] Meanwhile, the electrode terminal 50 may have various structures depending on the design of the preform and / or the caulking jig and / or the rivet washer 54 and the amount of pressure applied to the preform during the caulking process.

[0159] Figure 6b is a partially enlarged cross-sectional view showing the structure of an electrode terminal 50 ′ according to another embodiment of the present disclosure.

[0160] Reference Figure 6b , an electrode terminal 50' according to another embodiment of the present invention has a structure in which the inner flange portion 50c is riveted to be substantially parallel to the inner surface 52b of the bottom 52 of the battery can 51. Therefore, the angle formed by the surface of the inner flange portion 50c opposite to the inner surface 52b of the bottom 52 of the battery can 51 and the inner surface 52b is substantially close to 0, and the height (H3) of the inner flange portion 53c is less than the height (H2) of the inner gasket 54b. In addition, the inner edge 57 of the perforation 53 has an arc shape with a predetermined curvature. In addition, the side wall of the edge of the flat portion 50d has a structure inclined toward the flat portion 50d.

[0161] Preferably, the thickness of the inner gasket 54b may gradually decrease upward, decrease to a minimum thickness near the end of the inner flange portion 53c, and then slightly increase toward the uppermost end. The compression structure of the inner gasket 54b may further improve the sealing performance of the electrode terminal 50'. The compression ratio of the inner gasket 54b may be calculated at the minimum thickness point near the end of the inner flange portion 53c.

[0162] Preferably, the riveted structure of the electrode terminal 50 , 50 ′ according to the above-described embodiment of the present disclosure may be applied to a cylindrical battery cell having a form factor greater than 21700.

[0163] Recently, as cylindrical battery cells are applied to electric vehicles, the form factor of cylindrical battery cells is increasing compared to conventional form factors of 18650, 21700, etc. The increase in form factor leads to an increase in energy density, an increase in safety against thermal runaway, and an improvement in cooling efficiency.

[0164] In addition, as will be explained later, electrical wiring may be performed at one side of the cylindrical battery cell to which the riveted structure of the electrode terminal 50, 50' is applied. In addition, the electrode terminal 50, 50' having the riveted structure has a large cross-sectional area and low resistance, so it is very suitable for fast charging.

[0165] Preferably, the cylindrical battery cell to which the electrode terminal 50, 50' of the present disclosure is applied may have a shape factor ratio (defined as a value obtained by dividing the diameter of the cylindrical battery cell by the height, ie, a ratio of diameter (Φ) to height (H)) greater than about 0.4.

[0166] Here, the form factor refers to a value indicating the diameter and height of a cylindrical battery cell. The cylindrical battery cell according to an embodiment of the present disclosure may be, for example, 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 indicate the diameter of the cell, the next two digits indicate the height of the cell, and the last digit "0" indicates that the cross-section of the cell is circular. If the height of the cell exceeds 100 mm, the last digit 0 may be omitted because 3 digits are required to indicate the height of the cell.

[0167] The battery cell according to an embodiment of the present disclosure may be a cylindrical battery cell having an approximately cylindrical shape with a diameter of approximately 46 mm, a height of approximately 110 mm, and a shape factor ratio of 0.418.

[0168] A battery cell according to another embodiment may be a cylindrical battery cell having a substantially cylindrical shape with a diameter of about 48 mm, a height of about 75 mm, and an aspect ratio of 0.640.

[0169] A battery cell according to still another embodiment may be a cylindrical battery cell having an approximately cylindrical shape with a diameter of approximately 48 mm, a height of approximately 110 mm, and an aspect ratio of 0.418.

[0170] A battery cell according to still another embodiment may be a cylindrical battery cell having an approximately cylindrical shape, a diameter of approximately 48 mm, a height of approximately 80 mm, and an aspect ratio of 0.600.

[0171] A battery cell according to still another embodiment may be a cylindrical battery cell having an approximately cylindrical shape with a diameter of approximately 46 mm, a height of approximately 80 mm, and an aspect ratio of 0.575.

[0172] Generally, a battery cell having a shape factor ratio of about 0.4 or less is used. That is, for example, 18650 cells, 21700 cells, etc. are generally used. The 18650 cell has a diameter of approximately 18 mm, a height of approximately 65 mm, and a shape factor ratio of 0.277. The 21700 cell has a diameter of approximately 21 mm, a height of approximately 70 mm, and a shape factor ratio of 0.300.

[0173] Figure 7ais a cross-sectional view showing a cylindrical battery cell 70 according to an embodiment of the present disclosure, taken along a longitudinal direction (Y).

[0174] Reference Figure 7a According to this embodiment, the cylindrical battery cell 70 includes a jelly-roll type electrode assembly 71, in which a first electrode plate and a second electrode plate having a sheet shape are wound with a separator sandwiched therebetween, so that an uncoated portion 72 of the first electrode plate is exposed at a lower portion and an uncoated portion 73 of the second electrode plate is exposed at an upper portion.

[0175] In one embodiment, the first electrode plate may be a negative electrode plate and the second electrode plate may be a positive electrode plate, or vice versa.

[0176] Method and reference for winding electrode assembly 71 Figure 2 The method described for making the wound electrode assembly used in conventional tabless cylindrical battery cells is essentially the same.

[0177] In describing the electrode assembly 71 , only the uncoated portions 72 , 73 extending to be exposed to the outside of the separator are shown in detail, and the wound structure of the first electrode plate, the second electrode plate, and the separator is not shown in detail.

[0178] The cylindrical battery cell 70 further includes a cylindrical battery can 51 accommodating an electrode assembly 71 and electrically connected to an uncoated portion 72 of the first electrode plate.

[0179] Preferably, one side (lower portion) of the battery can 51 is open. In addition, the bottom 52 of the battery can 51 has a structure in which the electrode terminal 50 is riveted to the penetration hole 53 by a caulking process.

[0180] Specifically, the electrode terminal 50 may include a main body portion 50a inserted into the perforation 53, an outer flange portion 50b extending along the outer surface 52a from the circumference of one side of the main body portion 50a exposed through the outer surface 52a of the bottom 52 of the battery can 51, an inner flange portion 50c extending toward the inner surface 52b from the circumference of the other side of the main body portion 50a exposed through the inner surface 52b of the bottom 52 of the battery can 51, and a flat portion 50d arranged at the inner side of the inner flange portion 50c.

[0181] The electrode terminal 50 can be used Figure 6b The electrode terminal 50' is shown instead.

[0182] The cylindrical battery cell 70 may further include a rivet washer 54 interposed between the electrode terminal 50 and the penetration hole 53 .

[0183] The cylindrical battery cell 70 may further include a sealing body 74 that seals the open end of the battery can 51 to be insulated 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.

[0184] The cover plate 74a may be made of a conductive metal material such as aluminum, steel, nickel, etc. In addition, the sealing gasket 74b may be made of insulating and elastic polypropylene, polybutylene terephthalate, polyvinyl fluoride, etc. However, the present disclosure is not limited by the materials of the cover plate 74a and the sealing gasket 74b.

[0185] The cover plate 74a may include a venting notch 77 that ruptures when the pressure inside the battery can 51 exceeds a threshold value. The venting notch 77 may be formed at both sides of the cover plate 74a. The venting notch 77 may be formed in a continuous or discontinuous circular pattern, a linear pattern, or any other pattern on the surface of the cover plate 74a. The depth and width of the venting notch 77 may be set so that when the pressure inside the battery can 51 is 15 kgf / cm 2 Up to 35kgf / cm 2 The exhaust notch 77 ruptures when the exhaust notch 77 is within the range of .

[0186] The battery can 51 may include a curling portion 75 that extends and bends to the inside of the battery can 51 to surround the edge of the cover plate 74 a and fix the edge of the cover plate 74 a and the sealing gasket 74 b together to fix the sealing body 74 to the battery can 51 .

[0187] Preferably, the lower surface of the cover plate 74a may be located above the lower end of the curling portion 75. Then, a gas exhaust space is formed below the cover plate 74a so that when the gas exhaust recess 77 is broken, gas can be smoothly exhausted.

[0188] The battery can 51 may further include a crimping portion 76 pressed into the battery can 51 in a region adjacent to its open end. When the sealing body 74 is fixed by the crimping portion 75, the crimping portion 76 supports the edge of the sealing body 74, particularly the outer peripheral surface of the sealing gasket 74b.

[0189] The cylindrical battery cell 70 may also include a first current collecting plate 78 welded to the uncoated portion 72 of the first electrode plate. The first current collecting plate 78 is made of a conductive metal material such as aluminum, steel, nickel, etc. Preferably, at least a portion 78a of the edge of the first current collecting plate 78 that is not in contact with the uncoated portion 72 of the first electrode plate may be inserted between the edge pressing portion 76 and the sealing gasket 74b and fixed by the curling portion 75. Alternatively, at least a portion 78a of the edge of the first current collecting plate 78 may be fixed to the inner circumference 76a of the edge pressing portion 76 adjacent to the curling portion 75 by laser welding, spot welding, ultrasonic welding, etc.

[0190] The cylindrical battery cell 70 may further include a second current collecting plate 79 welded to the uncoated portion 73 of the second electrode plate. Preferably, at least a portion of the second current collecting plate 79, for example, a central portion 79a thereof, may be welded to the flat portion 50d of the electrode terminal 50.

[0191] Preferably, when welding the second current collecting plate 79, the welding tool can be inserted through the cavity 80 in the core of the electrode assembly 71 to reach the welding point of the second current collecting plate 79. In addition, when the second current collecting plate 79 is welded to the flat portion 50d of the electrode terminal 50, since the electrode terminal 50 supports the welding area of ​​the second current collecting plate 79, the welding quality can be improved by applying a strong pressure to the welding area. In addition, since the flat portion 50d of the electrode terminal 50 has a large area, a wide welding area can also be ensured. Therefore, the contact resistance of the welding area is reduced, thereby reducing the internal resistance of the cylindrical battery cell 70. The face-to-face welding structure of the riveted electrode terminal 50 and the second current collecting plate 79 is very useful for fast charging using a high C-rate current. This is because the current density per unit area in the cross section in the direction of current flow can be reduced, so the heat generated in the current path can be lower than that in the prior art.

[0192] When welding the flat portion 50 d of the electrode terminal 50 and the second current collecting plate 79 , any one of laser welding, ultrasonic welding, spot welding, and resistance welding may be used.

[0193] In one example, when the flat portion 50d and the second current collecting plate 79 are laser welded in a continuous or discontinuous line in the form of an arc pattern, the diameter of the arc welding pattern is 2 mm or more, preferably 4 mm or more. When the diameter of the arc welding pattern satisfies the corresponding conditions, the tension of the welding portion can be increased to 2 kgf or more, thereby ensuring sufficient welding strength.

[0194] In another example, when ultrasonically welding the flat portion 50d and the second current collecting plate 79 in a circular pattern, the diameter of the circular welding pattern is preferably 2 mm or more. When the diameter of the circular welding pattern satisfies the corresponding conditions, the tension of the welding portion can be increased to 2 kgf or more, thereby ensuring sufficient welding strength.

[0195] The diameter of the flat portion 50d corresponding to the weldable area can be adjusted within a range of 3 mm to 14 mm. If the radius of the flat portion 50d is less than 3 mm, it is difficult to form a welding pattern having a diameter of 2 mm or more using a laser welding tool, an ultrasonic welding tool, etc. In addition, if the radius of the flat portion 50d exceeds 14 mm, the size of the electrode terminal 50 becomes too large, and the area occupied by the outer surface 52a of the bottom 52 of the battery can 51 is reduced, making it difficult to connect the electrical connection component (bus bar) through the outer surface 52a.

[0196] Preferably, since the diameter of the welding pattern for fixing the tension of the welding part to 2 kgf or more is 2 mm or more, and the diameter of the weldable area is 3 mm to 14 mm, the area ratio of the welding pattern to the area of ​​the weldable area can be 2.04 (100*π12 / π72)% to 44.4 (100*π12 / π1.52)%.

[0197] The cylindrical battery cell 70 may further include an insulator 80. The insulator 80 may be interposed between the second current collecting plate 79 and the inner surface 52a of the bottom 52 of the battery can 51, and between the inner circumference 51a of the sidewall of the battery can 51 and the electrode assembly 71.

[0198] Preferably, the insulator 80 may have a welding hole 80a exposing the flat portion 50d of the electrode terminal 50 toward the second current collecting plate 79. In addition, the welding hole 80a may expose the inner flange portion 50c and the inner gasket 54b together with the flat portion 50d of the electrode terminal.

[0199] Preferably, the insulator 80 may cover the surface of the second current collecting plate 79 and one (upper) edge of the electrode assembly 71. By doing so, the second current collecting plate 79 having a polarity different from that of the battery can 51 can be prevented from contacting the uncoated portion 73 of the second electrode plate.

[0200] Preferably, the insulator 80 is made of an insulating resin and may include an upper plate 80b and a side sleeve 80c. In one example, the upper plate 80b and the side sleeve 80c may be integrally formed by injection molding. Alternatively, the side sleeve 80c may also be replaced by an insulating tape or the like. The insulating tape may cover the outer edge of the second current collecting plate 79 together with the uncoated portion 73 of the second electrode plate exposed by the periphery of the electrode assembly 71.

[0201] Preferably, the inner surface 52b of the insulator 80 and the bottom 52 of the battery can 51 may be in close contact with each other, such as Figure 7bHere, “close contact” means that there is no visually confirmed space (gap). In order to eliminate this space (gap), the distance from the inner surface 52b of the bottom 52 of the battery can 51 to the flat portion 50d of the electrode terminal 50 can be equal to or slightly less than the thickness of the insulator 80.

[0202] Preferably, the uncoated portions 72, 73 of the first electrode plate and / or the second electrode plate may be bent in a radial direction (e.g., from the periphery of the electrode assembly 71 to the core) to form curved surfaces at the upper and lower portions of the electrode assembly 71. In addition, the first current collecting plate 78 may be welded to the curved surface formed by bending the uncoated portion 72 of the first electrode plate, and the second current collecting plate 79 may be welded to the curved surface formed by bending the uncoated portion 73 of the second electrode plate.

[0203] In order to alleviate the stress generated when the uncoated portions 72, 73 are bent, the first electrode plate and / or the second electrode plate may have an improved structure different from that of a conventional electrode plate (see Figure 1 ).

[0204] Figure 8 2 is a plan view exemplarily showing the structure of an electrode plate 90 according to a preferred embodiment of the present disclosure.

[0205] Reference Figure 8 The electrode plate 90 has a sheet-shaped 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 an uncoated portion 93 formed at a long side end of the current collector 91 and not coated with the active material.

[0206] Preferably, the uncoated portion 93 may include a plurality of notched sections 93a. A plurality of sections 93a constitute a plurality of groups, and the sections 93a included in each group may have the same height (length on the Y direction) and / or the same width (length on the X direction) and / or the same spacing. The number of sections 93a belonging to each group may increase or decrease than shown. Section 93a has the shape of a geometric figure, in which at least one straight line and / or at least one curve are combined. Preferably, section 93a may have a trapezoidal shape, which may become a rectangle, a parallelogram, a semicircle, a semiellipse, etc. as required.

[0207] Preferably, the height of the segment 93a may be gradually increased along a direction parallel to the winding direction of the electrode assembly (e.g., from the core to the periphery). In addition, the core-side uncoated portion 93' adjacent to the core may not include the segment 93a, and the height of the core-side uncoated portion 93' may be less than the height of other uncoated portion areas. In addition, the peripheral uncoated portion 93" adjacent to the periphery may not include the segment 93a, and the height of the peripheral uncoated portion 93" may be less than the height of other uncoated portion areas.

[0208] Optionally, the electrode plate 90 may include an insulating coating 94 for covering the boundary between the active material layer 92 and the uncoated portion 93. The insulating coating 94 includes an insulating polymer resin and may optionally further include an inorganic filler. The insulating coating 94 prevents the end of the active material layer 92 from contacting the active material layer of the opposite polarity opposite to it through the separator, and is used to structurally support the bending of the segment 93a. For this reason, when the electrode plate 90 is wound into an electrode assembly, it is preferred that the insulating coating 94 is at least partially exposed to the outside from the separator.

[0209] Fig. 9 is a cross-sectional view taken along a longitudinal direction (Y) showing an electrode assembly 100 , in which a segment structure of an uncoated portion of an electrode plate 90 according to an embodiment of the present disclosure is applied to a first electrode plate and a second electrode plate.

[0210] Reference Fig. 9 The electrode assembly 100 can be referred to Figure 2 For ease of explanation, the protruding structure of the uncoated portions 72 and 73 extending from the separator is shown in detail, and the winding structure of the first electrode plate, the second electrode plate and the separator is not shown in detail. The uncoated portion 72 protruding downward extends from the first electrode plate, and the uncoated portion 73 protruding upward extends from the second electrode plate.

[0211] A pattern in which the height of the uncoated portions 72, 73 is changed is schematically shown. That is, the height of the uncoated portions 72, 73 may vary irregularly depending on the position at which the cross section is cut. For example, when the side portion of the trapezoidal segment 93a is cut, the height of the uncoated portion at the cross section is lower than the height of the segment 93a. Therefore, it should be understood that the height of the uncoated portions 72, 73 depicted in the drawings showing the cross section of the electrode assembly 100 corresponds to the average value of the height of the uncoated portion included in each winding turn.

[0212] The uncoated portions 72, 73 may be bent in the radial direction of the electrode assembly 100 (eg, from the periphery to the core), as shown in FIG. Fig.10a and Fig.10b As shown. Fig. 9 , the curved portion 101 is indicated by a dotted frame. When the uncoated portions 72, 73 are bent, as the segments adjacent to each other in the radial direction overlap each other in multiple layers, the curved surface 102 is formed at the upper and lower portions of the electrode assembly 100. At this time, the core-side uncoated portion 93' (see Figure 8) is not bent due to its low height, and the height (h) of the innermost bent segment is less than or equal to the radial length (r) of the winding area formed by the core-side uncoated portion 93' without a segment structure. Therefore, the cavity 80 in the core of the electrode assembly 100 is not closed by the bent segment. If the cavity 80 is not closed, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding tool through the cavity 80, the electrode terminal 50 and the second current collecting plate 79 can be easily welded.

[0213] In the cylindrical battery cell 70 according to an embodiment of the present disclosure, the cover plate 74a of the sealing body 74 has no polarity. In contrast, the first current collecting plate 78 is connected to the side wall of the battery can 51 so that 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 battery cells are connected in series and / or in parallel, wiring such as bus bar connection can be performed at the upper portion of the cylindrical battery cell 70 using the electrode terminal 50 and the outer surface 52a of the bottom 52 of the battery can 51. Thus, the energy density can be increased by increasing the number of battery cells that can be installed in the same space, and the electrical wiring work can be easily performed.

[0214] Fig.11 is a diagram showing a state in which the cylindrical battery cells 70 according to the embodiment of the present disclosure are electrically connected using the bus bar 150 .

[0215] Reference Fig.11 , a plurality of cylindrical battery cells 70 may be connected in series and in parallel at an upper portion using a bus bar 150. The number of cylindrical battery cells 70 may be increased or decreased in consideration of the capacity of the battery pack.

[0216] In each cylindrical battery cell 70 , the electrode terminal 50 may have a positive polarity, and the outer surface 52 a of the bottom 52 of the battery can 51 may have a negative polarity, or vice versa.

[0217] Preferably, a plurality of cylindrical battery cells 70 may be arranged in a plurality of columns and rows. The columns are arranged in the up-down direction relative to the ground, and the rows are arranged in the left-right direction relative to the ground. In addition, in order to maximize space efficiency, the cylindrical battery cells 70 may be arranged in the most compact packaging structure. When the centers of the electrode terminals 50 form an equilateral triangle when connected to each other, the most compact packaging structure is formed.

[0218] Preferably, the bus bar 150 may be disposed above a plurality of battery cells, more preferably disposed between adjacent columns. Alternatively, the bus bar 150 may be disposed between adjacent rows.

[0219] Preferably, the bus bar 150 connects the battery cells arranged in the same column to each other in parallel, and connects the battery cells arranged in two adjacent columns to each other in series.

[0220] Preferably, for both series and parallel connection, the bus bar 150 may include a body portion 151 , a plurality of first bus bar terminals 152 , and a plurality of second bus bar terminals 153 .

[0221] The body portion 151 may extend between the electrode terminals (50) of adjacent cylindrical battery cells 70, preferably between columns of cylindrical battery cells 70. Alternatively, the body portion 151 may extend along the columns of cylindrical battery cells 70 and may be regularly bent in a zigzag shape.

[0222] A plurality of first bus bar terminals 152 may protrude from one side of the body portion 151 toward the electrode terminal 50 of each cylindrical battery cell 70, and may be electrically connected to the electrode terminal 50. The electrical connection with the electrode terminal 50 may be achieved by laser welding, ultrasonic welding, etc. In addition, a plurality of second bus bar terminals 153 may protrude from the other side of the body portion 151 toward the outer surface 52a of the bottom 52 of the battery can 51 of each cylindrical battery cell 70, and may be electrically connected to the outer surface 52a. The electrical connection with the outer surface 52a may be performed by laser welding, ultrasonic welding, etc.

[0223] Preferably, the main body 151, the plurality of first bus bar terminals 152, and the plurality of second bus bar terminals 153 may be made of a conductive metal plate. The metal plate may be an aluminum plate or a copper plate, but the present disclosure is not limited thereto. In a modified example, the main body 151, the plurality of first bus bar terminals 152, and the plurality of second bus bar terminals 153 may be manufactured as separate pieces and then connected to each other by welding or the like.

[0224] In the cylindrical battery cell 70 according to the present disclosure, the electrode terminal 50 having positive polarity and the outer surface 52 a of the bottom 52 of the battery can 51 having negative polarity are located in the same direction, so the cylindrical battery cell 70 can be easily electrically connected using the bus bar 150 .

[0225] In addition, since the electrode terminal 50 and the outer surface 52 a of the cylindrical battery cell 70 have a large area, the coupling area of ​​the bus bar 150 may be sufficiently secured to sufficiently reduce the resistance of the battery pack including the cylindrical battery cell 70 .

[0226] Fig.12a is a partial enlarged view showing the electrical connection portion between the bus bar 150 and the cylindrical battery cell 70, Figure 12b and Fig.12c1 is a diagram showing definitions of various parameters for designing the diameter of the electrode terminal 50 and the upper and lower limits of the exposed width of the outer surface 52 a in consideration of the sizes of the bus bar terminals 152 , 153 .

[0227] Reference Fig.12a , Figure 12b and Fig.12c In the cylindrical battery cell 70 , the diameter ( E1 ) of the electrode terminal 50 and the width ( E2 ) of the annular outer surface 52 a may be adaptively adjusted in consideration of the size of the contact area of ​​the bus bar terminals 152 , 153 .

[0228] Here, the width E2 of the outer surface 52a is the width of the exposed surface parallel to the surface of the electrode terminal 50. Specifically, the width E2 of the outer surface 52a is defined as the width of a line segment connecting two points at which a straight line (L1) drawn in a radial direction from the center C of the electrode terminal 50 intersects the inner and outer boundaries of the outer surface 52a. The width E2 of the outer surface 52a is the width of a flat exposed surface excluding a circular area existing at the edge of the bottom 52 and an exposed area 54a' of the outer gasket 54a.

[0229] The outer surface of the bottom 52 of the battery can 51 can be divided into the electrode terminal 50, the exposed area 54a' of the rivet gasket 54, and the circular area R at the edge of the outer surface 52a when viewed from the top. The circular area R is a processing area for smoothly connecting the bottom 52 of the battery can 51 and the side wall of the battery can 51 (see Figure 7a and Figure 7b ), and has a width (R d ).

[0230] The first bus bar terminal 152 of the bus bar 150 branches to a side different from the traveling direction of the main body portion 151, and is electrically connected to the electrode terminal 50. At this time, the electrode terminal 50 and the first bus bar terminal 152 form a first overlapping area (shaded in the figure) on the plane, and the first overlapping area has a first width (W1). Here, the first overlapping area is an area where the electrode terminal 50 and the first bus bar terminal 152 overlap on the plane.

[0231] The first width (W1) is defined as the maximum value among the distances between any two points selected in the edge of the first overlap region. When the first overlap region includes the center of the electrode terminal 50 ( Figure 12b ) and when the first overlapping region does not include the center of the electrode terminal 50 ( Fig.12c ), the definition of the first width (W1) also applies. Figure 12b and Fig.12c , the distance represented by W1 corresponds to the maximum value among the distances between any two points selected in the edge of the first overlapping area.

[0232] The second bus bar terminal 153 of the bus bar 150 extends in a direction opposite to the first bus bar terminal 152 based on the traveling direction of the main body portion 151, and is electrically connected to the outer surface 52a of the bottom 52 of the battery can 51. At this time, the second bus bar terminal 153 and the outer surface 52a form a second overlapping area (shaded in the figure) on the plane, and the second overlapping area has a second width (W2). Here, the second overlapping area is an area where the outer surface 52a and the second bus bar terminal 153 overlap on the plane.

[0233] The second width ( W2 ) is defined as the maximum value among widths between two points at which each straight line intersects an edge of the second overlap region when a plurality of straight lines ( L3 ) are drawn from the center C of the electrode terminal 50 to pass through the second overlap region.

[0234] Preferably, the diameter (E1) of the electrode terminal 50 must be at least equal to or greater than the first width (W1) of the first bus bar terminal 152. This is because the first overlapping area of ​​the first bus bar terminal 152 and the electrode terminal 50 must not deviate from the electrode terminal 50 in the plane. In addition, the diameter (E1) of the electrode terminal 50 can be increased to a maximum until the distance between the boundary of the electrode terminal 50 and the second bus bar terminal 153 corresponds to the width (G) of the exposed area 54a' of the outer gasket 54a. Therefore, the maximum value of the diameter (E1) of the electrode terminal 50 is "D-2*Rd-2*G-2*W2".

[0235] Preferably, the width (E2) of the outer surface 52a is a factor that depends on the diameter (E1) of the electrode terminal 50, and must be at least equal to or greater than the second width (W2) of the second bus bar terminal 153. Only in this case, an overlapping area of ​​the second bus bar terminal 153 and the outer surface 52a can be formed. In addition, the width (E2) of the outer surface 52a can be increased to a maximum of up to 50% of "D-2*Rd-2*G-E1", which is obtained by subtracting the diameter (E1) of the electrode terminal 50, the width (2*G) of the exposed area of ​​the outer gasket 54a, and the width (2*Rd) of the circular area from the outer diameter (D) of the battery can 51. d ) and obtain the value.

[0236] In summary, in the cylindrical battery cell 70 according to the present disclosure, it is preferred that the diameter ( E1 ) of the electrode terminal 50 and the width ( E2 ) of the outer surface 52 a are designed to satisfy the following relational expression.

[0237] W1≤E1≤D-2R d -2G-2W2

[0238] E2=0.5*(D-2R d -2G-E1)

[0239] (E1: diameter of the electrode terminal 50, E2: width of the outer surface 52a, D: outer diameter of the battery can 51, R d : width of the circular region R measured on a plane, G: width of the exposed region 54a' of the outer gasket 54a, W1: width of the first bus bar terminal 152, W2: width of the second bus bar terminal 153)

[0240] In a specific example, when D is 46 mm, W1 and W2 are 6 mm, G is 0.5 mm, and R is 1 mm, the diameter ( E1 ) of the electrode terminal 50 is 6 mm to 31 mm, and the width ( E2 ) of the outer surface 52 a is 6 mm to 18.5 mm.

[0241] As another example, when D is 46 mm, W1 and W2 are 6 mm, G is 0.5 mm and R d When the thickness of the electrode terminal 50 is 1.5 mm, the diameter (E1) of the electrode terminal 50 is 6 mm to 30 mm, and the width (E2) of the outer surface 52a is 6 mm to 18 mm.

[0242] As described above, the cylindrical battery cell 70 of the present disclosure has a structure in which resistance is minimized by enlarging the welding area by means of the curved surface of the uncoated portion, reusing the current path by using the first current collecting plate, minimizing the current path length, etc. The AC resistance of the cylindrical battery cell 70 measured between the electrode terminal 50 (positive polarity terminal) and the outer surface 52a (negative polarity terminal) near the electrode terminal 50 using a resistance measuring instrument may be about 4 milliohms (mΩ) or less, for example, 0.5 mΩ to 4 mΩ, more preferably 1 mΩ to 4 mΩ, which is suitable for fast charging.

[0243] In the present disclosure, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may use any active material known in the art without limitation.

[0244] In one example, the positive electrode active material may include a x M y ]O 2+z An 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; the stoichiometric coefficients x, y and z are selected so that the compound maintains electrical neutrality).

[0245] In another example, the positive electrode active material may be an alkali metal compound xLiM disclosed in US Pat. No. 6,677,082, US Pat. No. 6,680,143, etc. 1 O2-(1-x)Li2M 2 O3, where M 1 comprising at least one element having an average oxidation state of 3; M 2 including at least one element having an average oxidation state of 4; and 0≤x≤1).

[0246] In yet another example, the positive electrode active material may be a material of the general formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z Lithium metal phosphate (M 1 Includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg and Al; M 2 including at least one element 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 Including a halogen element, 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 so that the compound maintains electrical neutrality; or a lithium metal phosphate represented by the general formula Li3M2(PO4)3 (M includes at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg and Al).

[0247] Preferably, the positive electrode active material may include primary particles and / or secondary particles in which primary particles are aggregated.

[0248] In one example, the negative electrode active material can be a carbon material, lithium metal or lithium metal compound, silicon or silicon compound, tin or tin compound, etc. Metal oxides such as TiO2 and SnO2 with a potential less than 2V can also be used as negative electrode active materials. As the carbon material, low crystalline carbon and / or high crystalline carbon can be used.

[0249] The separator may use a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., or a laminate thereof. As another example, the separator may use a common porous nonwoven fabric, for example, a nonwoven fabric made of a high melting point glass fiber, a polyethylene terephthalate fiber, etc.

[0250] A coating of inorganic particles may be included in at least one surface of the separator. The separator itself may also be made of a coating of inorganic particles. The particles in the coating may be bonded with a binder so that there is an interstitial volume between adjacent particles.

[0251] 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 may include at least one material selected from the group consisting of: Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), BaTiO3, hafnium dioxide (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0252] The electrolyte may be a + B - Here, A + Including alkali metal cations such as Li + 、Na + or K + , or a combination thereof. And B - comprising at least one 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 - .

[0253] The electrolyte may also be dissolved in an organic solvent. The organic solvent may use 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.

[0254] The cylindrical battery cell 70 according to the above-described embodiment may be used to manufacture a battery pack.

[0255] Fig.13 is a diagram schematically showing a battery pack according to an embodiment of the present disclosure.

[0256] Reference Fig.13 , a battery pack 200 according to an embodiment of the present disclosure includes an assembly in which cylindrical battery cells 201 are electrically connected and a battery pack case 202 for accommodating the assembly. The cylindrical battery cells 201 are battery cells according to the above-described embodiment. In the figure, for ease of illustration, components such as bus bars, cooling units, and external terminals for electrical connection of the cylindrical battery cells 201 are not shown.

[0257] The battery pack 200 may be mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheel vehicle or a two-wheel vehicle.

[0258] Fig.14 It is used to show that Fig.13 Illustration of a battery pack 200 for a vehicle.

[0259] Reference Fig.14 The vehicle V according to the embodiment of the present disclosure includes the battery pack 200 according to the embodiment of the present disclosure. According to the embodiment of the present disclosure, the vehicle V runs by receiving power from the battery pack 200.

[0260] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present disclosure, are given by way of illustration only, since various changes and modifications within the scope of the present disclosure will become apparent to those skilled in the art from this detailed description.

Claims

1. A riveting structure of an electrode terminal, the riveting structure comprising: a battery can configured to have one open side; an electrode terminal riveted through a perforation formed in the bottom of the battery can; as well as a rivet washer, the rivet washer being inserted between the electrode terminal and the through hole, Wherein, the electrode terminal comprises: a main body portion, the main body portion being inserted into the through hole; an outer flange portion configured to extend from a circumference of one side of the body portion exposed by the outer surface of the bottom of the battery can along the outer surface of the bottom of the battery can; an inner flange portion configured to extend from a circumference of the other side of the body portion exposed through the inner surface of the bottom of the battery can toward the inner surface of the bottom of the battery can; and a weldable area provided to the inner side of the inner flange portion, The inner flange portion has a thickness that gradually decreases as it moves away from the main body portion.

2. The riveting structure of the electrode terminal according to claim 1, in, The flat portion is parallel to the inner surface of the bottom.

3. The riveting structure of the electrode terminal according to claim 1, in, An angle between the inner flange portion and the inner surface of the bottom is 0° to 60°.

4. The riveting structure of the electrode terminal according to claim 1, in, The concave portion has a cross-sectional structure of an asymmetric groove.

5. The riveting structure of the electrode terminal according to claim 1, in, The side wall is perpendicular to the inner surface of the bottom.

6. The riveting structure of the electrode terminal according to claim 1, in, The side walls slope toward the flat portion.

7. The riveting structure of the electrode terminal according to claim 1, in, The rivet gasket comprises: an outer gasket interposed between the outer flange portion and the outer surface of the bottom, and an inner gasket interposed between the inner flange portion and the inner surface of the bottom, Wherein, the inner gasket has different thicknesses according to its position.

8. The riveting structure of the electrode terminal according to claim 7, in, A region of the inner gasket interposed between an inner edge of the through hole connected to the inner surface of the bottom and the inner flange portion has a relatively smaller thickness than other regions.

9. The riveting structure of the electrode terminal according to claim 7, in, A region of the inner gasket interposed between the through hole and the main body portion has a thickness gradually decreasing as being farther away from the outer flange portion.

10. The riveting structure of the electrode terminal according to claim 7, in, A region of the inner gasket interposed between the inner surface of the bottom portion and a region near an end of the inner flange portion has a minimum thickness.

11. The riveting structure of the electrode terminal according to claim 7, in, The inner edge of the perforation includes a facing surface facing the inner flange portion.

12. The riveting structure of the electrode terminal according to claim 7, in, The inner gasket is configured to extend longer than the inner flange portion such that an end portion of the inner gasket is exposed.

13. The riveting structure of the electrode terminal according to claim 7, in, A height of the flat portion is equal to or greater than a height of an end portion of the inner gasket based on the inner surface of the bottom.

14. The riveting structure of the electrode terminal according to claim 1, in, A height of the flat portion is equal to or greater than a height of the inner flange portion based on the inner surface of the bottom portion.

15. The riveting structure of the electrode terminal according to claim 7, in, The height of the inner flange portion is greater than the height of an end portion of the inner gasket based on the inner surface of the bottom portion.

16. The riveting structure of the electrode terminal according to claim 1, in, The height of the inner flange portion is 0.5 mm to 3.0 mm based on the inner surface of the bottom of the battery can.

17. The riveting structure of the electrode terminal according to claim 16, in, A height of the electrode terminal extending from a lower surface of the outer flange portion to a surface of the flat portion is 4 mm to 7 mm.

18. The riveting structure of the electrode terminal according to claim 1, in, The height of the outer flange portion is 0.8 mm or more based on the outer surface of the bottom of the battery can.

19. The riveting structure of the electrode terminal according to claim 7, in, At least a portion of the outer gasket is exposed to the outside of the outer flange portion, and An exposed width of the outer gasket measured in a direction parallel to the outer surface of the bottom of the battery can is 0.1 mm to 1 mm.

20. The riveting structure of the electrode terminal according to claim 7, in, A radius from a center of the body portion to an edge of the outer flange portion is 10% to 70% of a radius of the bottom of the battery can.

21. The riveting structure of the electrode terminal according to claim 1, in, A radius from the center of the body portion to the edge of the flat portion is 4% to 30% of a radius of the bottom portion.

22. The riveting structure of the electrode terminal according to claim 7, in, When a ratio of a thickness change at a maximum compression point compared to a thickness of the rivet gasket before compression is defined as a compression ratio, the compression ratio of the inner gasket is 30% to 90%.

23. The riveting structure of the electrode terminal according to claim 22, in, The inner gasket comprises polybutylene terephthalate, polyvinyl fluoride or polypropylene, and The compression ratio of the inner gasket is 50% to 90%.

24. A cylindrical battery cell, comprising: An electrode assembly, in which a first electrode plate and a second electrode plate having a sheet shape are wound with a separator sandwiched therebetween, the electrode assembly having an uncoated portion of the first electrode plate and an uncoated portion of the second electrode plate, the uncoated portion of the first electrode plate and the uncoated portion of the second electrode plate being configured to extend from both ends of the electrode assembly and be exposed to the outside of the separator; a cylindrical battery can configured to accommodate the electrode assembly and electrically connected to the first electrode plate; an electrode terminal riveted and electrically connected to the second electrode plate through a perforation formed in the bottom of the battery can; The electrode terminal comprises: a main body portion, the main body portion being inserted into the through hole; an outer flange portion configured to extend from a circumference of one side of the body portion exposed by the outer surface of the bottom of the battery can along the outer surface of the bottom of the battery can; an inner flange portion configured to extend from a circumference of the other side of the body portion exposed through the inner surface of the bottom of the battery can toward the inner surface of the bottom of the battery can; and a weldable area provided to the inner side of the inner flange portion, a rivet washer interposed between the electrode terminal and the through hole; and A sealing body is configured to seal the open end of the battery can so as to be insulated from the battery can, wherein the inner flange portion has a thickness that gradually decreases as it moves away from the main body portion.

25. The cylindrical battery cell according to claim 24, in, The battery can includes a pressed edge portion formed in a region adjacent to the open end and pressed into the battery can, and The sealing body includes a non-polar cover plate and a sealing gasket interposed between an edge of the cover plate and the open end of the battery can.

26. The cylindrical battery cell according to claim 25, in, The battery can further includes a curling portion extending and bending to an interior of the battery can and configured to surround the edge of the cover plate and fix the edge of the cover plate and the sealing gasket together.

27. The cylindrical battery cell according to claim 25, in, The cover plate includes a vent recess that ruptures when the pressure inside the battery can exceeds a threshold value.

28. The cylindrical battery cell according to claim 27, in, When the pressure inside the battery can is 15kgf / cm 2 Up to 35kgf / cm 2 When within the range of , the exhaust notch ruptures.

29. The cylindrical battery cell according to claim 25, further comprising: a first current collecting plate coupled to the uncoated portion of the first electrode plate, Wherein, at least a portion of the edge of the first current collecting plate that is not in contact with the uncoated portion of the first electrode plate is interposed between the edge pressing portion and the sealing gasket and fixed by the curling portion.

30. The cylindrical battery cell according to claim 29, in, At least a portion of the edge of the first current collecting plate is fixed to an inner circumference of the pressing portion adjacent to the curling portion by welding.

31. The cylindrical battery cell of claim 24, further comprising: a second current collecting plate coupled to the uncoated portion of the second electrode plate, Wherein, at least a portion of the second current collecting plate is coupled to a flat portion of the electrode terminal.

32. The cylindrical battery cell according to claim 31, in, The second current collecting plate and the flat portion of the electrode terminal are coupled by welding, and A tension of a welding portion between the second current collecting plate and the flat portion of the electrode terminal is 2 kgf or more.

33. The cylindrical battery cell according to claim 32, in, A converted diameter of the welding pattern exposed on the surface of the second current collecting plate is 2 mm or more.

34. The cylindrical battery cell according to claim 33, in, The flat portion of the electrode terminal has a diameter of 3 mm to 14 mm.

35. The cylindrical battery cell according to claim 33, in, A ratio of an area of ​​the welding pattern exposed on the surface of the second current collecting plate to an area of ​​the flat portion of the electrode terminal is 2.04% to 44.4%.

36. The cylindrical battery cell of claim 31 , further comprising: An insulator is interposed between the second current collecting plate and an inner circumference of the bottom of the battery can and between an inner circumference of a side wall of the battery can and the electrode assembly.

37. The cylindrical battery cell according to claim 36, in, The insulator has a welding hole formed to expose the flat portion of the electrode terminal toward the second current collecting plate and to cover a surface of the second current collecting plate and an edge of one side of the electrode assembly.

38. The cylindrical battery cell according to claim 37, in, A height from the inner surface of the bottom of the battery can to the flat portion of the electrode terminal is equal to or smaller than a thickness of the insulator.

39. The cylindrical battery cell according to claim 37, in, The rivet gasket comprises: an outer gasket interposed between the outer flange portion and the outer surface of the bottom of the battery can; and An inner gasket is interposed between the inner flange portion and the inner surface of the bottom of the battery can.

40. The cylindrical battery cell according to claim 39, in, An end portion of the inner gasket is exposed to the outside of the inner flange portion.

41. The cylindrical battery cell according to claim 39, in, The welding hole exposes the flat portion and the inner flange portion of the electrode terminal.

42. The cylindrical battery cell according to claim 40, in, The welding hole exposes the flat portion, the inner flange portion, and the inner gasket of the electrode terminal.

43. The cylindrical battery cell according to claim 24, in, A first bus bar terminal is electrically coupled to a surface of the electrode terminal, and a second bus bar terminal is electrically coupled to the outer surface of the bottom of the battery can.

44. The cylindrical battery cell according to claim 43, in, The first bus bar terminal overlaps with the electrode terminal in a plane to form a first overlapping region, and the second bus bar terminal overlaps with the outer surface of the bottom of the battery can to form a second overlapping region, and The diameter of the electrode terminal and the width of the outer surface of the bottom of the battery can can satisfy the following relational expression, W1≤E1≤D-2R d -2G-2W2 E2=0.5*(D-2R d -2G-E1) Wherein, E1: diameter of the electrode terminal, E2: width of the exposed surface parallel to the surface of the electrode terminal in the outer surface of the bottom of the battery can, D: outer diameter of the battery can, R d : the width of the circular area at the edge of the battery can measured on a plane, G: the exposed width of the outer gasket through the edge of the electrode terminal, W1: the maximum value among the distances between any two points selected in the edge of the first overlapping area, W2: the maximum value among the distances between two points at the intersection of multiple straight lines passing through the center of the electrode terminal and the edge of the second overlapping area.

45. The cylindrical battery cell according to claim 24, in, An aspect ratio obtained by dividing the diameter of the cylindrical battery cell by the height is greater than 0.

4.

46. ​​A battery pack comprising a plurality of cylindrical battery cells, the cylindrical battery cells being the cylindrical battery cells according to any one of claims 24 to 45.

47. The battery pack according to claim 46, in, The plurality of cylindrical battery cells are arranged in a predetermined number of columns, and The electrode terminal and the outer surface of the bottom of the battery can of each cylindrical battery cell are disposed to face upward.

48. The battery pack according to claim 47, further comprising: a plurality of bus bars configured to connect the plurality of cylindrical battery cells in series and in parallel, wherein the plurality of bus bars are disposed above the plurality of cylindrical battery cells, Each bus bar includes: a body portion configured to extend between electrode terminals of adjacent cylindrical battery cells; a plurality of first bus bar terminals respectively configured to extend from the body portion in one side direction and to be electrically coupled to the electrode terminals of the cylindrical battery cells located in the one side direction; and A plurality of second bus bar terminals are respectively configured to extend from the main body portion in the other side direction and electrically coupled to the outer surface of the bottom of the battery can of the cylindrical battery cell located in the other side direction.

49. The battery pack according to claim 47, in, An AC resistance of the cylindrical battery cell measured between the electrode terminal and the outer surface of the bottom of the battery can is 4 milliohms or less.

50. A vehicle comprising at least one battery pack according to any one of claims 46 to 48.

Images