The fixing structure of the electrode terminals and the battery, battery pack and automobile including the electrode terminals.

Abstract

This invention relates to a fixing structure for electrode terminals and batteries, battery packs, and automobiles including the same. The fixing structure for electrode terminals includes: a battery casing having an open end on one side and a bottom having a through-hole on the other side; an electrode terminal fixed to the bottom; and a terminal gasket sandwiched between the electrode terminal and the bottom. The electrode terminal includes: a neck having a cross-section smaller than that of the through-hole and inserted into the through-hole; a head connected to one end of the neck, having a cross-section larger than that of the through-hole, and extending along one surface of the bottom; a protrusion connected to the other end of the neck, extending from the other surface of the bottom along the axial direction of the battery casing; an enlarged diameter portion extending centrifugally from the protrusion; and a front end face disposed at the axial end of the protrusion, wherein the enlarged diameter portion is a connecting member physically attached to the outer peripheral surface of the protrusion.

Description

Technical Field

[0001] This invention relates to a fixing structure for electrode terminals and batteries, battery packs, and automobiles including the same. Background Technology

[0002] Besides portable devices, rechargeable batteries, with their high applicability and high energy density, are also widely used in electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), which are driven by electric power sources. Electric vehicles, as discussed below, include EVs, HEVs, and PHEVs.

[0003] Such secondary batteries not only have the primary advantage of significantly reducing the use of fossil fuels, but also have the advantage of producing no byproducts with the use of energy. Therefore, they are attracting much attention as a new energy source that is environmentally friendly and improves energy efficiency.

[0004] Currently, widely used rechargeable batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. These rechargeable batteries typically operate at voltages between 2.5V and 4.5V. Therefore, if a higher power voltage is required, multiple batteries are sometimes connected in series to form a battery pack. Furthermore, depending on the required charge / discharge capacity of the battery pack, multiple batteries are sometimes connected in parallel to form a battery pack. Thus, depending on the required power voltage and / or charge / discharge capacity, the number of batteries and their electrical connections within a battery pack can be designed in various ways.

[0005] On the other hand, as types of secondary battery units, cylindrical, square, and pouch batteries are disclosed. A cylindrical battery has a separator membrane, serving as an insulator, sandwiched between the anode and cathode, and this membrane is rolled up to form a gel-roll-shaped electrode assembly. This assembly, along with an electrolyte, is then inserted into the battery casing to form the battery. Furthermore, the uncoated portions of both the anode and cathode can be connected to strip-shaped electrode tabs, which electrically connect the electrode assembly to the exposed electrode terminals. For reference, the anode terminal is a cap that seals the opening of the battery casing, and the cathode terminal is the battery casing itself.

[0006] However, according to existing cylindrical batteries with this structure, the current is concentrated on the strip electrode tabs that are combined with the uncoated portion of the anode and / or the uncoated portion of the cathode, resulting in problems such as high resistance, high heat generation, and low current collection efficiency.

[0007] For small cylindrical batteries with a form factor of 1865 or 2170, resistance and heat generation are not major issues. However, when the form factor is increased to make cylindrical batteries suitable for electric vehicles, a lot of heat is generated around the electrode tabs during fast charging, which could potentially lead to a fire in the cylindrical battery.

[0008] To address this issue, a cylindrical battery with an improved current-collecting efficiency (a so-called tabless cylindrical battery) has been disclosed. The design features an uncoated anode and an uncoated cathode located at the upper and lower ends of a gel roll-type electrode assembly, respectively, with the current collector welded to such uncoated portions.

[0009] Figures 1 to 3 This is a diagram illustrating the manufacturing process of a tabless cylindrical battery. Figure 1 The structure of the electrode is shown. Figure 2 The electrode winding process is shown. Figure 3 The process of welding the current collector to the bent surface of the uncoated part is shown. Figure 4 This is a cross-sectional view of a tabless cylindrical battery cut along its length direction Y.

[0010] Reference Figures 1 to 4 The anode 10 and cathode 11 have a structure in which an active material 21 is coated on the sheet current collector 20, and along the winding direction X, an uncoated portion 22 is included on one long side.

[0011] like Figure 2 As shown, electrode assembly A is manufactured by sequentially stacking the anode 10 and cathode 11 together with two separation membranes 12 and then winding them in one direction X. At this time, the uncoated portions of the anode 10 and cathode 11 are arranged in opposite directions.

[0012] After the winding process, the uncoated portion 10a of the anode 10 and the uncoated portion 11a of the cathode 11 are bent toward the core. Then, the current collectors 30 and 31 are welded to the uncoated portions 10a and 11a respectively to achieve bonding.

[0013] The uncoated anode portion 10a and the uncoated cathode portion 11a are not connected to any other electrode tabs. The current collectors 30 and 31 are connected to external electrode terminals along the winding axis direction of the electrode assembly A (refer to...). Figure 3 The arrow (symbol) forms a current path with a large cross-sectional area, thus having the advantage of reducing battery resistance. This is because resistance is inversely proportional to the cross-sectional area of ​​the current path.

[0014] However, if the shape factor of a cylindrical battery increases and the charging current becomes larger during rapid charging, the heating problem will reappear in tabless cylindrical batteries.

[0015] Specifically, such as Figure 4 As shown, a conventional tabless cylindrical battery 40 includes a battery casing 41 and a sealing body 42. The sealing body 42 includes a cover 42a, a sealing gasket 42b, and a connecting plate 42c. The sealing gasket 42b surrounds the edge of the cover 42a and is fixed by a clamping part 43. In addition, to prevent upstream and downstream movement, the electrode assembly A is fixed inside the battery casing 41 by a rolled edge part 44.

[0016] Typically, the anode terminal is the cover 42a of the sealing body 42, and the cathode terminal is the battery casing 41. Therefore, the current collector 30, which is attached to the uncoated portion 10a of the anode 10, is electrically connected to the connecting plate 42c attached to the cover 42a via a strip-shaped lead 45. In addition, the current collector 31, which is attached to the uncoated portion 11a of the cathode 11, is electrically connected to the bottom of the battery casing 41.

[0017] The insulator 46 covers the current collector 30 to prevent the battery casing 41 and the uncoated part 10a of the anode 10, which have different polarities, from coming into contact with each other and causing a short circuit.

[0018] When connecting the current collector 30 to the connecting plate 42c, a strip-shaped lead 45 is used. The lead 45 is attached separately to the current collector 30 or is integrally formed with the current collector 30. However, the lead 45 is a thin strip, and therefore has a small cross-sectional area, thus generating more heat when a rapid charging current flows. In addition, the excessive heat generated from the lead 45 is transferred to the electrode assembly A side, causing the separation membrane 12 to shrink, which is the main cause of thermal runaway, namely internal short circuit.

[0019] That is, according to the conventional cylindrical battery structure, the current collector 31 portion opposite to the bottom of the battery casing 41 is directly connected to the bottom of the battery casing 41, thus ensuring a sufficiently large cross-sectional area in the direction of current movement, and therefore there is no problem of overheating. Conversely, the current collector 30, which is connected to the sealing body 42 pressed against the opening of the battery casing 41, is connected to the sealing body 42 via a strip-shaped lead 45, and therefore can only cause the overheating problem described above.

[0020] Furthermore, in the manufacturing process, the leads 45 occupy a considerable amount of space within the battery casing 41. Therefore, the cylindrical battery 40, including the leads 45, has low space efficiency, thus limiting its ability to increase energy density.

[0021] Furthermore, in the past, connecting tabless cylindrical batteries 40 in series and / or parallel required connecting bus components to the cover 42a of the sealing body 42 and the bottom surface of the battery casing 41, thus reducing space efficiency. Battery packs in electric vehicles comprise hundreds of cylindrical batteries 40. Therefore, the inefficiency of the electrical wiring also causes considerable trouble for the assembly process of electric vehicles and the maintenance of the battery pack.

[0022] In addition, the pressing part 43 located on the edge side of the sealing body 42 is exposed on the upper part of the cylindrical battery 40 as a part with negative polarity. Figure 4 The upper part of the clamping part 43 is relatively large, but the area of ​​the clamping part 43 exposed at the top is actually much smaller than the area of ​​the sealing body 42. Therefore, in order to stably connect the bus components, only the sealing body 42 and the bottom of the battery casing 41 that are clamped to the opening of the battery casing 41 can be used. Summary of the Invention

[0023] The problem that the invention aims to solve

[0024] This invention was developed to solve the above-mentioned problems. The purpose of this invention is to improve the electrode terminal structure of the cylindrical battery to increase the space efficiency inside the battery casing, thereby reducing the internal resistance of the cylindrical battery and increasing the energy density.

[0025] Another technical challenge of this invention is to improve the electrode terminal structure of the cylindrical battery to increase the cross-sectional area of ​​the current path, thereby improving the internal heat generation problem during rapid charging.

[0026] Another technical objective of the present invention is to provide a cylindrical battery with an improved structure for realizing electrical wiring operations for series and / or parallel connections of cylindrical batteries, wherein an improved structure is performed on one side of the cylindrical battery.

[0027] Another technical objective of the present invention is to provide a battery pack manufactured using a cylindrical battery with an improved structure and an automobile including the same.

[0028] The technical challenges of this invention are not limited to the objectives mentioned above. Other objectives and advantages of this invention not mentioned herein will be understood through the following description, and will become clearer through embodiments of the invention. Furthermore, the objectives and advantages of this invention can obviously be achieved by the means described in the claims and combinations thereof.

[0029] Methods for solving problems

[0030] To achieve the above-mentioned technical problem, the fixing structure of the electrode terminal on one side of the present invention includes: a battery casing having an open end on one side and a bottom having a through hole on the other side; an electrode terminal fixed to the bottom; and a terminal pad sandwiched between the electrode terminal and the bottom.

[0031] The electrode terminal includes: a neck having a cross-section smaller than that of the through hole and inserted into the through hole; a head connected to one end of the neck and having a cross-section larger than that of the through hole, extending along one side surface of the bottom; a protrusion connected to the other end of the neck and extending from the other side surface of the bottom along the axial direction of the battery casing; an enlarged diameter portion extending from the protrusion in a centrifugal direction; and a front end face disposed at the axial end of the protrusion, wherein the enlarged diameter portion is a connecting member physically attached to the outer peripheral surface of the protrusion.

[0032] The outer peripheral surface of the aforementioned protrusion has a connecting groove formed along the circumferential direction and recessed in the centripetal direction, into which the aforementioned connecting member is inserted and fixed.

[0033] The aforementioned connecting groove is in the shape of an external thread, and the aforementioned connecting component is a nut having an internal thread that connects with the aforementioned external thread.

[0034] The aforementioned connecting groove is an O-shaped groove, and the aforementioned connecting component is a C-shaped ring inserted into the aforementioned O-shaped groove.

[0035] The surface of the connecting component facing the bottom includes a sidewall surface that gradually moves away from the bottom as it approaches the outer side in the radial direction.

[0036] When the connecting component is engaged with the connecting groove, the side wall faces the bottom of the battery casing and presses the terminal pad against it.

[0037] The aforementioned electrode terminal fixing structure further includes: a first sealing coating, which is formed at the interface between the terminal gasket and the bottom of the battery casing.

[0038] The aforementioned first sealing coating includes silicone resin, silicone acrylate, or polyamide imide.

[0039] The aforementioned electrode terminal fixing structure further includes a second sealing coating that covers the external exposed interface between the aforementioned connecting component and the aforementioned terminal gasket.

[0040] Optionally, the second sealing coating covers the external exposed interface between the terminal gasket and the bottom.

[0041] The aforementioned second sealing coating includes silicone resin, silicone acrylate, or polyamide imide.

[0042] With the bottom surface of the battery casing as a reference, the front end face protrudes further than the enlarged diameter portion in the axial direction of the battery casing.

[0043] The aforementioned front end surface includes a flat portion with a flat surface.

[0044] The aforementioned connecting component has a first section that extends from the aforementioned protrusion in a centrifugal direction and gradually moves away from the bottom of the aforementioned battery casing.

[0045] In the first interval mentioned above, the angle formed between the surface of the connecting member facing the bottom and the bottom exceeds 0 degrees and is less than 60 degrees.

[0046] In the aforementioned enlarged section, the diameter of the cross-section cut along a direction perpendicular to the central axis of the battery casing is larger than the diameter of the aforementioned through hole.

[0047] In the aforementioned expanded diameter section, the diameter of the cross-section cut along a direction perpendicular to the central axis of the battery casing gradually increases as it moves away from the bottom of the battery casing.

[0048] The portion of the terminal pad sandwiched between the head and the bottom of the battery casing is in a crimped state.

[0049] In order to achieve the above-mentioned technical problem, the battery of another aspect of the present invention includes a fixing structure for electrode terminals having at least one of the above-mentioned features.

[0050] The battery includes: an electrode assembly formed by winding a first electrode and a second electrode with a separator membrane sandwiched between them, and including uncoated portions of the first electrode and the second electrode extending from both ends and protruding outside the separator membrane; a battery casing having an open end on one side, through which the electrode assembly is housed and electrically connected to the first electrode; an electrode terminal provided through a through-hole without contacting the inner wall of the through-hole formed at the bottom of the battery casing, and electrically connected to the second electrode, and including: a neck having a cross-section smaller than that of the through-hole and inserted into the through-hole; and a head. The following components are provided: a portion of the battery casing connected to one end of the neck, having a cross-section larger than that of the through hole, and extending along one side surface of the bottom; a protrusion connected to the other end of the neck, extending from the other side surface of the bottom along the axial direction of the battery casing; an enlarged diameter portion extending from the protrusion in the centrifugal direction; a front end face disposed at the axial end of the protrusion, the enlarged diameter portion being a connecting member physically attached to the outer peripheral surface of the protrusion; a terminal gasket sandwiched between the electrode terminal and the through hole; and a sealing body sealing the open end of the battery casing to insulate it from the battery casing.

[0051] The battery casing includes a rolled edge pressed into the inside of the battery casing in the region adjacent to the open end, and the sealing body includes a non-polar cap and a sealing gasket sandwiched between the edge of the cap and the open end of the battery casing.

[0052] The battery casing further includes a clamping part that extends and bends inward toward the inside of the battery casing to surround the edge of the cover together with the sealing gasket and fix it in place.

[0053] The battery further includes: a first current collector, which is coupled to the uncoated portion of the first electrode, wherein at least a portion of the edge of the first current collector that does not contact the uncoated portion of the first electrode is sandwiched between the rolled edge and the sealing gasket and is fixed by the clamping portion.

[0054] At least a portion of the edge of the first current collector is fixed to the inner circumferential surface of the rolled edge portion adjacent to the clamping portion by welding.

[0055] The battery further includes a second current collector, which is bonded to the uncoated portion of the second electrode, and at least a portion of the second current collector is welded to the front end face of the electrode terminal.

[0056] The battery further includes an insulator sandwiched between the second current collector and the bottom inner peripheral surface of the battery casing, and between the inner peripheral surface of the side wall of the battery casing and the electrode assembly.

[0057] The battery is cylindrical, and the shape factor of the battery's diameter divided by its height is greater than 0.4.

[0058] The AC resistance measured through the electrode terminals of the battery and the outer surface of the bottom of the battery casing is less than 4 milliohms.

[0059] The technical objective of this invention is achieved by a battery pack comprising a plurality of the aforementioned batteries and a vehicle comprising such batteries.

[0060] Invention Effects

[0061] According to one aspect of the invention, the electrode terminal structure of a cylindrical battery is improved to omit leads, thereby increasing the space efficiency within the battery casing, thereby reducing the internal resistance of the cylindrical battery and increasing the energy density.

[0062] According to another aspect of the invention, the electrode terminal structure of the cylindrical battery is improved so that the electrode terminals and the current collector are directly connected, and the internal heat generation problem during rapid charging is improved by increasing the cross-sectional area of ​​the current path.

[0063] According to another aspect of the invention, both electrodes are disposed on one side, i.e., the bottom, of the cylindrical battery, thereby enabling electrical wiring operations for connecting the cylindrical batteries in series and / or in parallel to be performed on one side of the cylindrical battery.

[0064] According to another aspect of the invention, it is possible to provide a battery pack manufactured using a cylindrical battery with an improved structure and an automobile including the same.

[0065] The above-mentioned effects and the specific effects of the present invention will be described together with the description of the specific embodiments. Attached Figure Description

[0066] Figure 1 This is a top view showing the structure of the electrodes used in conventional tabless cylindrical batteries.

[0067] Figure 2 This diagram illustrates the winding process of electrode assemblies included in conventional tabless cylindrical batteries.

[0068] Figure 3 It is shown in Figure 2 A diagram showing the process of welding the current collector to the bent surface of the uncoated part in the electrode assembly.

[0069] Figure 4 This is a cross-sectional view of a conventional tabless cylindrical battery cut along the length direction Y.

[0070] Figure 5 This is a cross-sectional view showing the fixing structure of the electrode terminals according to the first embodiment of the present invention.

[0071] Figure 6 Is Figure 5 The diagram shows only the enlarged portion of the electrode terminals.

[0072] Figure 7 Is Figure 5 Enlarged cross-sectional view of the part indicated by the dashed circle.

[0073] Figure 8 This is a cross-sectional view of a cylindrical battery according to an embodiment of the present invention, cut along the YZ plane.

[0074] Figure 9 This is a magnified view of a modified example of the electrode terminals of the first embodiment.

[0075] Figure 10 and Figure 11 This is a diagram showing an enlarged view of the electrode terminals of the second embodiment.

[0076] Figure 12 and Figure 13 This is a cross-sectional view showing the application of a sealing coating to the fixing structure of the electrode terminals, including the electrode terminals of the second embodiment.

[0077] Figure 14 This is a magnified view of a modified example of the electrode terminals of the second embodiment.

[0078] Figure 15 and Figure 16 This is a cross-sectional view showing the case where a sealing coating is applied to the fixing structure of the electrode terminals in a modified example including the second embodiment.

[0079] Figure 17 This is a top view illustrating an electrode structure of a preferred embodiment of the present invention.

[0080] Figure 18 This is a cross-sectional view of an electrode assembly that incorporates the uncoated segment structure of the electrode of an embodiment of the present invention into the first electrode and the second electrode, cut along the length direction Y.

[0081] Figure 19 This is a cross-sectional view of the electrode assembly of the uncoated portion of an embodiment of the present invention, cut along the length direction Y.

[0082] Figure 20 This is a diagram illustrating a schematic structure of a battery pack including a cylindrical battery according to an embodiment of the present invention.

[0083] Figure 21 This is a diagram illustrating a schematic structure of a car including a battery pack according to an embodiment of the present invention. Detailed Implementation

[0084] Referring to the accompanying drawings, the above-described objectives, features, and advantages will be described in detail below, thereby enabling those skilled in the art to readily implement the technical concept of the present invention. In describing the present invention, detailed descriptions are omitted where it is determined that a specific description of well-known techniques related to the present invention would obscure the essence of the invention. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same symbols denote the same or similar constituent elements.

[0085] Although terms such as "first," "second," etc., are used to describe various constituent elements, these terms do not limit these constituent elements. These terms are only used to distinguish one constituent element from other constituent elements, and in the absence of a particularly contradictory statement, the first constituent element can also be the second constituent element.

[0086] Throughout the specification, unless otherwise stated, each constituent element may be a single element or a plurality of elements.

[0087] In the following description, when any structure is arranged on the "upper (or lower) part" or "upper (or lower)" of a constituent element, it means not only that the arbitrary structure is connected to the upper (or lower) surface of the constituent element, but also that other structures are sandwiched between the constituent element and the arbitrary structure arranged on the upper (or lower) part of the constituent element.

[0088] In addition, when a constituent element is described as being "connected", "combined", or "connected" with other constituent elements, the constituent elements can be directly connected or connected to each other, or they can be "sandwiched" between each constituent element or connected, "combined", or "connected" through other constituent elements.

[0089] Unless otherwise specified in the text, the singular used in this specification includes multiple meanings. In this application, terms such as "constituting" or "comprising" do not necessarily mean that all the constituent elements or steps described in the specification must be included, or that some constituent elements or steps may be excluded, or additional constituent elements or steps may be included.

[0090] Throughout the specification, when referred to as “A and / or B”, unless otherwise stated otherwise, this means A, B, or A and B; when referred to as “C to D”, unless otherwise stated otherwise, this means C and below.

[0091] For ease of explanation, in this specification, the direction along the length of the winding axis of the electrode assembly wound in a gel roll form is referred to as the axial direction Y. Furthermore, the direction surrounding the winding axis is referred to as the circumferential direction or the surrounding direction X. And, the direction closer to or farther from the winding axis is referred to as the radial direction or the radial direction Z. Specifically, the direction closer to the winding axis is referred to as the centripetal direction, and the direction farther from the winding axis is referred to as the centrifugal direction.

[0092] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0093] The fixing structure of the electrode terminal 50 of the present invention is suitable for cylindrical battery casing H structure.

[0094] The cylindrical battery casing H described above has a cylindrical sidewall 51 and a bottom 52 connected to the end of the sidewall 51. Thus, the cylindrical battery casing H has a structure in which one side is open and the other side is sealed by the bottom 52.

[0095] The electrode assembly 71 is inserted into the interior of the battery housing H through the open side of the battery housing H, and the front end of the electrode assembly 71 (the end portion of the electrode assembly that is inserted first) is inserted until it reaches the bottom 52 of the battery housing H.

[0096] A through hole 53 is formed at the bottom 52 of the battery casing H.

[0097] The bottom 52 includes a first surface 52a and a second surface 52b that are opposite to each other. The through hole 53 is a hole formed through the bottom 52, communicating with a first space opposite to the first surface 52a and a second space opposite to the second surface 52b.

[0098] The first surface 52a is the surface exposed to the outside of the battery casing H, thus the first space is the external space of the battery casing H. The second surface 52b is the surface facing the inside of the battery casing H, thus the second space is the internal space of the battery casing H.

[0099] Conversely, the second surface 52b can be the surface exposed to the outside of the battery casing H, and the first surface 52a can be the surface facing the inside of the battery casing H. In this case, the second space is the external space of the battery casing H, and the first space is the internal space of the battery casing H.

[0100] The first surface 52a and the second surface 52b mentioned above correspond to the outer surface and inner surface of the bottom 52 of the battery casing H, respectively.

[0101] The aforementioned through hole 53 is located near the center of the bottom 52 of the aforementioned battery casing H.

[0102] Before housing the electrode assembly 71 into the battery casing H, insert the electrode terminal 50 into the through hole 53 and fix the electrode terminal 50 to the bottom 52 of the battery casing H.

[0103] As an example, the electrode terminal 50 is fixed by means of a plastically formed portion 50c1 formed by plastic forming. Such plastic forming includes riveting, caulking, etc.

[0104] As another example, electrode terminal 50 can be connected via a separate connecting component ( Figure 10 50c2 or Figure 14 The 50c2 and 50c3 are fixed together. Such connecting parts include nuts, locking rings, etc.

[0105] like Figure 6 As shown, the electrode terminal 50 includes: a neck 50a having a cross-section smaller than that of the through hole 53; and a head 50b disposed at one end of the neck 50a having a cross-section larger than that of the through hole 53. A protrusion 50e having a cross-section smaller than that of the through hole 53 is provided at the other end of the neck 50a.

[0106] The protrusion 50e of the electrode terminal 50 is inserted through the through hole 53 on the first surface 52a side of the bottom 52 of the battery casing H. Then, the edge of the protrusion 50e is plastically processed on the second surface 52b side of the bottom 52 of the battery casing H to form a plastically processed part 50c1, or a connecting component (50c2 or...) is physically fixed to the protrusion 50e. Figure 14 50c3).

[0107] The aforementioned plastic forming part 50c1 or the aforementioned connecting parts 50c2 and 50c3 constitute an enlarged diameter part E that expands the cross-sectional area of ​​the aforementioned protrusion 50e. As a result, the cross-section of the aforementioned protrusion 50e is larger than the cross-section of the aforementioned through hole 53, and the aforementioned electrode terminal 50 remains in a fixed state inserted into the aforementioned through hole 53.

[0108] The aforementioned electrode terminal 50 is inserted through a through hole 53 in the bottom 52 outside the battery casing H. A protrusion 50e is formed inside the battery casing H by plastic forming, or a connecting component 50c2 or 50c3 is fixedly connected to the protrusion 50e. Thus, the head 50b of the electrode terminal 50 protrudes outside the battery casing H, and the protrusion 50e of the electrode terminal 50 is disposed inside the battery casing H.

[0109] As a countermeasure, the electrode terminal 50 is inserted through the through hole 53 in the bottom 52 inside the battery casing H, and a protrusion 50e is formed on the outside of the battery casing H by plastic forming, or a connecting component 50c2, 50c3 is fixedly connected to the protrusion 50e. In this way, the head 50b of the electrode terminal 50 is disposed inside the battery casing H, and the protrusion 50e of the electrode terminal 50 is exposed to the outside of the battery casing H.

[0110] The surface of the head 50b of the aforementioned electrode terminal 50 (the surface exposed in the axial direction) has a flat area. This flat area provides a contact surface for buses, etc.

[0111] In one embodiment, the protrusion 50e of the electrode terminal 50 is enlarged in cross-section by riveting.

[0112] The protrusion 50e of the electrode terminal 50 has a plastic processing part 50c1 formed by plastic deformation through riveting and a front end face 50d provided at the front end of the protrusion 50e.

[0113] The aforementioned plastic forming part 50c1 constitutes the diameter expansion part E.

[0114] The aforementioned front end face 50d is positioned further inward (inward in the radial direction) than the aforementioned plastic processing part 50c1.

[0115] The aforementioned front end face 50d includes a flat portion D with a flat surface.

[0116] The aforementioned front end face 50d generally forms a flat portion D.

[0117] The aforementioned front end surface 50d is a surface that has already been formed before the riveting is completed. That is, the aforementioned front end surface 50d is the area that does not deform through the aforementioned riveting.

[0118] The aforementioned front end face 50d has a surface that protrudes more in the axial direction than the aforementioned enlarged diameter portion E.

[0119] The aforementioned plastic forming portion 50c1 has a first section 501c that gradually moves away from the bottom 52 of the aforementioned battery casing H as it extends from the aforementioned protrusion 50e in the centrifugal direction.

[0120] In the first interval 501c mentioned above, the angle formed between the surface of the plastic processing part 50c1 facing the bottom 52 and the bottom 52 exceeds 0 degrees and is less than 60 degrees.

[0121] In one side, such as Figure 6 As shown, the aforementioned plastic forming section 50c1 is composed solely of the aforementioned first section 501c. On another side, as... Figure 9 As shown, the plastic forming section 50c1 further includes a second section 502c, which is positioned closer to the centrifugal side than the first section 501c and is connected to the first section 501c. The second section 502c gradually approaches the bottom 52 of the battery casing H as it extends in the centrifugal direction.

[0122] In the second interval 502c mentioned above, the angle Φ formed by the surface of the plastic processing part 50c1 facing the bottom 52 and the bottom 52 exceeds 0 degrees and is less than 30 degrees.

[0123] A groove portion 55 recessed in the axial direction is provided between the aforementioned plastic forming portion 50c1 and the aforementioned front end face 50d. The aforementioned groove portion 55 is a closed loop shape that surrounds the aforementioned front end face 50d in the circumferential direction.

[0124] Preferably, the aforementioned channel portion 55 has an asymmetrical groove cross-sectional structure. That is, the side wall surface 55a of the aforementioned flat portion D and the side wall surface 55b of the aforementioned plastic forming portion 50c1 are not parallel to each other.

[0125] When the aforementioned channel portion 55 is plastically deformed towards the enlarged diameter portion E by riveting to the upper part of the protrusion 50e, the external force applied for plastic deformation is prevented from affecting the flat portion D. Therefore, the size and shape of the flat portion D remain unchanged after riveting.

[0126] The side wall surface 55a connecting the bottom of the aforementioned ditch portion 55 and the aforementioned flat portion D is perpendicular to the plane including the aforementioned flat portion D. This maximizes the area of ​​the flat region of the flat portion D.

[0127] The side wall surface 55b of the plastic processing part 50c1, which is opposite to the side wall surface 55a of the flat part D, forms an inclined surface.

[0128] Preferably, the thickness of the expanded diameter portion E gradually decreases as it moves away from the protrusion 50e.

[0129] In another embodiment, the protrusion 50e of the electrode terminal 50 is enlarged in cross-section by the physical connection of the connecting components 50c2 and 50c3.

[0130] Reference Figure 10 The outer peripheral surface of the protrusion 50e of the electrode terminal 50 has a connecting groove 50g that extends in the circumferential direction. The connecting groove 50g is a groove shape with a reduced cross-section of the protrusion 50e. That is, the connecting groove 50g is a shape that is recessed from the outer peripheral surface of the protrusion 50e in the inward direction.

[0131] Reference Figure 11 As the connecting member 50c2 is inserted into the connecting groove 50g and fixed in place, the protrusion 50e and the connecting member 50c2 become integrated, thereby expanding the cross-section in the upper region of the protrusion 50e. That is, after the connecting member 50c2 is connected to the protrusion 50e, it forms the enlarged diameter portion E of the protrusion 50e. In one example, the connecting groove 50g is an O-ring, and the connecting member 50c2 is a C-ring inserted into the O-ring.

[0132] Reference Figure 14 The aforementioned connecting groove 50g has an external thread shape, and the aforementioned connecting component 50c3 is a nut with an internal thread.

[0133] The surfaces of the connecting components 50c2 and 50c3 facing the bottom 52 of the battery casing H have a shape that gradually moves away from the bottom 52 as they approach the outer side in the radial direction.

[0134] Reference Figure 11 and Figure 14 The front end face 50d of the aforementioned protrusion 50e has a flat portion D, which maintains its size and shape regardless of the connection of the aforementioned connecting parts 50c2 and 50c3.

[0135] A terminal gasket 54 is sandwiched between the electrode terminal 50 and the bottom 52 of the battery casing H.

[0136] The terminal gasket 54 is sandwiched between the head 50b and the bottom 52 of the electrode terminal 50, between the neck 50a of the electrode terminal 50 and the inner peripheral surface of the through hole 53, and between the enlarged diameter E of the protrusion 50e of the electrode terminal 50 and the bottom 52. Thus, the terminal gasket 54 can insulate the electrode terminal 50 and the bottom 52, and provide air tightness for the battery casing H.

[0137] The sidewalls (faces opposite to the bottom 52) of the aforementioned plastic forming part 50c1 or the aforementioned connecting parts 50c2 and 50c3 press the terminal gasket 54 together, thereby further pulling the aforementioned head 50b toward the first surface 52a of the aforementioned bottom 52. As a result, the portion of the terminal gasket 54 sandwiched between the aforementioned head 50b and the aforementioned first surface 52a of the aforementioned bottom 52 is forcefully pressed together.

[0138] In addition, the side wall surface (the surface opposite to the bottom 52) of the plastic forming part 50c1 or the connecting parts 50c2 and 50c3 shall forcefully press the terminal gasket 54 at the corner where the inner peripheral surface of the through hole 53 and the second surface 52b of the bottom 52 are connected.

[0139] Reference Figure 12 and Figure 15 The electrode terminal 50 fixing structure of an embodiment of the present invention includes a first sealing coating f1 formed between the terminal gasket 54 and the bottom 52 of the battery casing H. The first sealing coating f1 is sandwiched between the terminal gasket 54 and the bottom 52 of the battery casing H to improve the sealing performance of the terminal gasket 54.

[0140] Reference Figure 13 and Figure 16 The fixing structure of the electrode terminal 50 in an embodiment of the present invention includes a second sealing coating f2 covering the external exposed interface between the terminal gasket 54 and the bottom 52 of the battery casing H and / or the external exposed interface between the connecting components 50c2, 50c3 and the terminal gasket 54. The second sealing coating f2, like the first sealing coating f1, improves the sealing performance of the terminal gasket 54.

[0141] Those skilled in the art should understand that the first sealing coating f1 and / or the second sealing coating f2 described above are not necessary requirements, but rather optional requirements.

[0142] The first sealing coating f1 and / or the second sealing coating f2 described above are made of materials with excellent sealing properties and resistance to electrolytes. Silicone resin, silicone acrylate, or polyamide-imide can be used as materials for the sealing coatings f1 and f2, but the present invention is not limited thereto.

[0143] The embodiments of the present invention will now be described in more detail.

[0144] The cylindrical battery of the first embodiment of the present invention includes electrode terminals riveted to the bottom of the battery casing.

[0145] Figure 5 This is a cross-sectional view showing the riveting structure of the electrode terminal 50 according to an embodiment of the present invention. Figure 6 This is a cross-sectional view showing only the enlarged portion of electrode terminal 50. Figure 7 This is an enlarged cross-sectional view of the part indicated by the dashed circle.

[0146] Reference Figure 5 , Figure 6 and Figure 7 The riveting structure of the electrode terminal 50 in the embodiment includes a cylindrical battery casing H with one side open, an electrode terminal 50 riveted through a through hole 53 formed in the bottom 52 of the battery casing H, and a terminal pad 54 sandwiched between the electrode terminal 50 and the through hole 53.

[0147] The battery casing H is made of a conductive metal. In one example, the battery casing H is made of steel or aluminum, but the invention is not limited thereto. The battery casing H includes a cylindrical sidewall 51 and a bottom 52 connected to the end of the sidewall. The bottom 52 is integrally formed with the sidewall 51. For example, with respect to the battery casing H, the sidewall 51 and the bottom 52 are integrally formed by drawing a sheet metal using a stamping press.

[0148] The through hole 53 formed in the bottom 52 is formed by drilling a hole in the bottom 52 after the side wall 51 and the bottom 52 are shaped.

[0149] The electrode terminal 50 is made of a conductive metal. In one example, the electrode terminal 50 is made of aluminum or steel, but the invention is not limited thereto.

[0150] The terminal gasket 54 is made of a polymer resin that has insulating and elastic properties. In one example, the terminal gasket 54 is made of polypropylene, polybutylene terephthalate, polyvinyl fluoride, etc., but the invention is not limited thereto.

[0151] Preferably, the electrode terminal 50 includes a neck 50a inserted into the through hole 53, a head 50b exposed through the outer surface 52a of the bottom 52, and a protrusion 50e exposed through the inner surface 52b of the bottom 52 of the battery casing H and extending in the axial direction.

[0152] The head 50b extends further outward in the radial direction than the neck 50a. The diameter of the head 50b is larger than the diameter of the through hole 53.

[0153] The aforementioned protrusion 50e includes an enlarged diameter portion E extending outward in the radial direction from its periphery and a flat portion D disposed on the inner side in the radial direction of the enlarged diameter portion E.

[0154] The aforementioned enlarged diameter portion E is formed by plastic deformation of the upper edge portion of the aforementioned protrusion 50e, which is smaller than the aforementioned through hole 53, by expanding it outward in the radial direction. That is, the aforementioned enlarged diameter portion E is a plastically processed portion 50c1.

[0155] In one example, the plastic forming part 50c1 is formed by a riveting process using a caulking fixture. After riveting, the diameter of the enlarged part E is further increased than the diameter of the through hole 53.

[0156] The front end face 50d of the aforementioned protrusion 50e is a surface located at the end of the aforementioned protrusion 50e, and provides a flat portion D facing the axial direction.

[0157] Preferably, the flat portion D and the inner surface 52b of the bottom 52 of the battery casing H are parallel to each other. Here, 'parallel' means that they are substantially parallel when viewed with the naked eye.

[0158] Based on one aspect, such as Figure 6 As shown, the expanded diameter portion E includes a first section 501c that gradually moves away from the inner surface 52b as it approaches the centrifugal side. The angle θ between the surface of the first section 501c of the expanded diameter portion E facing the bottom 52 and the inner surface 52b of the bottom 52 is 0 degrees or more and 60 degrees or less.

[0159] The magnitude of angle θ is determined by the riveting strength when the electrode terminal 50 is positioned in the through hole 53 of the battery casing H using a riveting method. In one example, as the riveting strength increases, angle θ decreases until it reaches 0 degrees. When the angle exceeds 60 degrees, the sealing effect of the terminal gasket 54 decreases.

[0160] According to another perspective, such as Figure 9 As shown, the expanded diameter portion E has a shape comprising a first section 501c that gradually moves away from the inner surface 52b as it approaches the centrifugal side, and a second section 502c that connects to the centrifugal side end of the first section 501c and gradually moves closer to the inner surface 52b as it approaches the centrifugal side. The angle Φ between the surface of the second section 502c of the expanded diameter portion E facing the bottom 52 and the inner surface 52b of the bottom 52 exceeds 0 degrees and is less than 30 degrees.

[0161] The second interval 502c is reshaped after the first interval 501c is formed.

[0162] The second section 502c presses down on the terminal pad 54, causing the terminal pad 54 to lie down along the bottom 52 instead of standing upright on the inner surface 52b of the bottom 52. When the angle exceeds 30 degrees, excessive plastic deformation may occur at the boundary between the first section 501c and the second section 502c.

[0163] The aforementioned second section 502c provides a structure in which the enlarged diameter portion E does not protrude further than the flat portion D in the axial direction. This minimizes the height of the flat portion D protruding in the axial direction, thereby improving the utilization of the internal space of the battery casing H.

[0164] The aforementioned front end face 50d protrudes further in the axial direction than the aforementioned enlarged diameter portion E.

[0165] According to another perspective, a channel portion 55 is provided between the enlarged diameter portion E and the flat portion D. The channel portion 55 has an asymmetrical groove cross-sectional structure. In one example, the asymmetrical groove is approximately "V" to "U" shaped. The asymmetrical groove includes a side wall surface 55a on the flat portion D side and a side wall surface 55b on the opposite enlarged diameter portion E side. The aforementioned side wall surface 55a is substantially perpendicular to the inner surface 52b of the bottom 52 of the battery casing H. 'Perpendicular' means substantially perpendicular when viewed with the naked eye. The channel portion 55 is formed by the shape of the sealing clamp when the electrode terminal 50 is provided in the through hole 53 of the battery casing H.

[0166] Preferably, the thickness of the expanded diameter portion E gradually decreases towards the outer side in the radial direction. This thickness reduction structure provides a compact structure that allows the terminal pad 54 to be fully pressed in the centripetal direction of the expanded diameter portion E while preventing the end of the expanded diameter portion E from protruding more than the flat portion D in the centrifugal direction. In this way, the height of the flat portion D protruding in the axial direction can be minimized, thereby improving the utilization of the internal space of the battery casing.

[0167] According to another aspect, the terminal gasket 54 includes an outer gasket 54a sandwiched between the head 50b and the outer surface 52a of the bottom 52, and an inner gasket 54b sandwiched between the enlarged diameter portion E and the inner surface 52b of the bottom 52.

[0168] Reference Figure 7The outer gasket 54a and the inner gasket 54b have different thicknesses depending on their positions. Preferably, in the region of the inner gasket 54b, the area sandwiched between the inner edge 56 of the through hole 53 connected to the inner surface 52b of the bottom 52 of the battery casing H and the enlarged diameter portion E is relatively thin. Preferably, there is a minimum thickness portion in the gasket area sandwiched between the inner edge 56 of the through hole 53 and the enlarged diameter portion E. In addition, the inner edge 56 of the through hole 53 includes a facing surface 57 opposite to the enlarged diameter portion E. The facing surface 57 functions to prevent the pressure of the enlarged diameter portion E pressing the terminal gasket 54 from being excessively concentrated on the slope of the inner edge 56 portion.

[0169] On the other hand, the upper and lower ends of the inner peripheral wall of the through hole 53, which forms a perpendicular shape to the bottom 52, are corner-cut in a manner that forms a tapered surface toward the electrode terminal 50. However, the upper and / or lower ends of the inner wall of the through hole 53 may also be formed by a gently curved surface with curvature. In this case, the pressure applied to the terminal pad 54 can be further relieved near the upper and / or lower ends of the inner wall of the through hole 53.

[0170] The internal gasket 54b forms an angle of 0 to 60 degrees with the inner surface 52b of the bottom 52 of the battery casing H and extends longer than the expanded diameter portion E. This prevents the centrifugal end of the expanded diameter portion E from contacting the bottom 52 of the battery casing H.

[0171] On another side, with reference to the inner surface 52b of the bottom 52 of the battery casing H, the height H1 of the flat portion D is greater than or equal to the height H2 of the end of the inner gasket 54b. Furthermore, with reference to the inner surface 52b of the bottom 52 of the battery casing H, the height H1 of the flat portion D is greater than or equal to the height H3 of the end of the enlarged diameter portion E.

[0172] When the height parameters H1, H2 and H3 meet the above conditions, interference between the expanded diameter section E and the internal gasket 54b and other components (e.g., the second current collector described later) can be prevented.

[0173] Reference Figure 5 Based on the radius R2 of the bottom 52, the radius R1 from the center of the electrode terminal 50 to the edge of the head 50b is 10% to 60%.

[0174] When R1 is small, there will be insufficient space for soldering electrical wiring components (buses) at electrode terminals 50. Conversely, when R1 is large, the soldering space will be reduced when soldering electrical wiring components (buses) on the outer surface 52a of the bottom 52 of the battery casing H, excluding electrode terminals 50.

[0175] By adjusting the ratio R1 / R2 between 10% and 60%, adequate welding space can be ensured for the outer surfaces of the relative electrode terminals 50 and the bottom 52.

[0176] In addition, based on the radius R2 of the bottom 52, the radius R3 from the center of the electrode terminal 50 to the edge of the flat portion D is 4% to 30%.

[0177] When R3 decreases, a current collector is welded to the flat portion D of electrode terminal 50 (refer to...). Figure 8 When the welding space is insufficient (79), the welding area of ​​electrode terminal 50 will decrease, resulting in an increase in contact resistance.

[0178] In addition, in order to insert the electrode terminal 50 into the through hole 53, R3 can only be smaller than the radius of the through hole 53. Within this limitation, the larger R3 becomes, the thinner the thickness of the enlarged diameter portion E becomes, thereby weakening the force of the enlarged diameter portion E pressing the terminal gasket 54, resulting in a decrease in the sealing ability of the terminal gasket 54.

[0179] When adjusting R3 / R2 between 4% and 30%, such as Figure 8 As shown, the flat portion D of the electrode terminal 50 and the welding area of ​​the second current collector 79 can be fully ensured, thereby not only making the welding process easier, but also reducing the contact resistance of the welding area, thereby preventing the sealing ability of the terminal gasket 54 from decreasing.

[0180] According to an embodiment of the present invention, the riveting structure of the electrode terminal 50 is formed using a plug-sealing jig that moves up and down. First, a pre-form (not shown) of the electrode terminal 50 is inserted into a through hole 53 formed in the bottom 52 of the battery casing H, with a terminal pad 54 clamped in between. The pre-form refers to the electrode terminal before riveting.

[0181] Next, the sealing clamp is inserted into the inner space of the battery casing H. The sealing clamp forms the electrode terminal 50 for riveting the clamping sheet, and has grooves and protrusions on the surface opposite to the clamping sheet that correspond to the final shape of the electrode terminal 50.

[0182] Next, the sealing clamp is moved downward to press and shape the upper part of the pressure plate, thereby plastically deforming it using the electrode terminals 50 of the riveted pressure plate.

[0183] The pressing depth of the aforementioned plug-sealing fixture is limited by the aforementioned front end face 50d. Therefore, even during mass production, the shape of the expanded diameter portion E undergoing plastic deformation can be uniformly controlled.

[0184] Furthermore, the aforementioned front end face 50d does not deform or hardly deforms during the pressing process of the aforementioned sealing fixture. Therefore, the front end face 50d can also maintain a uniform shape during mass production. This ensures that the front end face 50d and the current collector ( Figure 8 The welding process of 79) is easier, thereby significantly reducing manufacturing deviations.

[0185] During the pressure application of the tablet by the sealing clamp, the outer gasket 54a, sandwiched between the outer surface 52a of the head 50b and the bottom 52, is elastically compressed, thereby reducing its thickness. Additionally, the portion of the inner gasket 54b sandwiched between the inner edge 56 of the through-hole 53 and the tablet is elastically compressed by the enlarged diameter portion E, further reducing its thickness compared to other areas. Specifically, the area where the thickness of the inner gasket 54b is concentrated is... Figure 7 The portion shown is indicated by the single dashed circle. As a result, the sealing and airtightness between the riveted electrode terminal 50 and the battery casing H are significantly improved.

[0186] Preferably, the terminal gasket 54 is compressed sufficiently in a manner that ensures the desired sealing strength without physically damaging it during the riveting process.

[0187] In one example, when the terminal gasket 54 is made of polybutylene terephthalate, the compression ratio of the terminal gasket 54 is preferably 50% or more at the position where it is compressed to its minimum thickness. The compression ratio is the ratio of the change in thickness before and after compression relative to the thickness before compression.

[0188] In another example, where the terminal gasket 54 is made of polyvinyl fluoride, it is preferable that the compression rate of the terminal gasket 54 at the position where it is compressed to its minimum thickness is 60% or more.

[0189] In another example, where the terminal gasket 54 is made of polypropylene, it is preferable that the compression rate of the terminal gasket 54 at the location where it is compressed to its minimum thickness is 60% or more.

[0190] Preferably, the sealing clamp is moved up and down at least twice, and the upper part of the pressure plate is pressurized and formed in stages. That is, the pressure plate is pressed and formed in stages and plastically deformed in multiple stages. At this time, the pressure applied to the sealing clamp is increased in stages. In this way, stress is applied to the pressure plate in multiple stages, thereby preventing damage to the terminal gasket 54 during the sealing process. In particular, when the inner gasket 54b portion sandwiched between the inner edge 56 of the through hole 53 and the pressure plate is compressed in a concentrated manner through the diameter expansion portion E, damage to the gasket can be minimized.

[0191] like Figure 7 As shown, after the pressing and forming of the sheet using the sealing clamp is completed, the sealing clamp is separated from the battery casing H, thereby obtaining the fixing structure of the electrode terminal 50 of the embodiment of the present invention.

[0192] According to the above embodiment, the sealing fixture presses and shapes the upper part of the sheet by moving up and down inside the battery casing H. Depending on the situation, a rotary jig used in the prior art can be used for pressing and shaping the sheet.

[0193] However, the annular rotary fixture rotates at a predetermined angle with respect to the central axis of the battery casing H. Therefore, the large radius of rotation of the annular rotary fixture causes interference between it and the inner wall of the battery casing H. Furthermore, as the depth of the battery casing H increases, the length of the annular rotary fixture also increases accordingly. In this case, when the radius of rotation at the end of the annular rotary fixture becomes large, the pressurization forming of the pressed sheet cannot be achieved effectively. Therefore, pressurization forming using a plug-sealing fixture is more efficient than using an annular rotary fixture.

[0194] The aforementioned enlarged diameter portion E can be formed not only by the plastic processing described above, but also by using physical connecting parts 50c2 and 50c3.

[0195] Reference Figure 10 and Figure 11 The protrusion 50e of the aforementioned electrode terminal 50 is enlarged in the axial direction by being engaged with the connecting member 50c2. The connecting member 50c2 is a C-shaped locking ring.

[0196] The outer peripheral surface of the protrusion 50e of the electrode terminal 50 has a connecting groove 50g that extends in the circumferential direction. The connecting groove 50g is an annular groove shape with a reduced cross-section of the protrusion 50e.

[0197] like Figure 10 As shown, the connecting member 50c2 is pressed into the connecting groove 50g from the front end face 50d side of the protrusion 50e. During this process, the C-shaped locking ring elastically deforms by expanding its radius, and then elastically recovers by shrinking its radius when inserted into the connecting groove 50g, thus firmly connecting to the connecting groove 50g.

[0198] When the connecting member 50c2 is inserted into the connecting groove 50g and fixed, the connecting member 50c2 and the protrusion 50e become integrated. Thus, the protrusion 50e has a structure in which the cross-section is further enlarged in the radial direction along the axial direction. That is, after the connecting member 50c2 and the protrusion 50e are connected, they form the enlarged diameter portion E of the protrusion 50e.

[0199] The surface of the connecting member 50c2 facing the bottom 52 has a shape that moves away from the bottom 52 as it approaches the outer side in the radial direction. Therefore, the connecting member 50c2, like the first section 501c of the plastic forming part 50c1, has a structure that is inclined at a predetermined angle θ relative to the bottom 52.

[0200] Reference Figure 12 and Figure 13To enhance the sealing of the electrode terminal 50, a first sealing coating f1 is located between the terminal gasket 54 and the bottom 52 of the battery casing H. This first sealing coating f1 is pre-formed on the bottom 52 and the through hole 53 of the battery casing H before the electrode terminal 50 is disposed in the through hole 53.

[0201] Optionally, to enhance the sealing of the electrode terminal 50, a second sealing coating f2 covers the external exposed interface between the terminal gasket 54 and the bottom 52 of the battery casing H, and / or the external exposed interface between the connecting component 50c2 and the terminal gasket 54. The second sealing coating f2 is formed by spraying after the electrode terminal 50 is installed.

[0202] Those skilled in the art should understand that, in this invention, the first sealing coating f1 and / or the second sealing coating f2 are not essential requirements, but rather optional requirements.

[0203] The first sealing coating f1 and / or the second sealing coating f2 described above are made of materials with excellent sealing properties and resistance to electrolytes. Silicone resin, silicone acrylate, or polyamide-imide can be used as materials for the sealing coatings f1 and f2, but the present invention is not limited thereto.

[0204] Reference Figure 14 The electrode terminal 50 mentioned above includes an enlarged diameter portion E formed by a bolt / nut connection structure.

[0205] Specifically, a connecting groove 50g with an external thread shape is formed on the upper outer peripheral surface of the protrusion 50e of the electrode terminal 50. Furthermore, the connecting member 50c3 is a nut with an internal thread formed on its inner peripheral surface.

[0206] The surface of the connecting member 50c3 with the nut structure described above, facing the bottom 52 of the battery casing H, has a shape that gradually moves away from the bottom 52 as it approaches the outer side in the radial direction. Therefore, the connecting member 50c3, like the first section 501c of the plastic forming part 50c1, has a structure that is inclined at a predetermined angle θ relative to the bottom 52, thus providing a seal by pressing the terminal gasket 54.

[0207] In the second embodiment, the front end face 50d of the protrusion 50e has a flat portion D. Furthermore, the flat portion D protrudes further than the connecting member 50c3 in the axial direction. Additionally, the flat portion D is unaffected by the connection of the connecting member 50c3, maintaining its size and shape.

[0208] Reference Figure 15 and Figure 16To enhance the sealing of the electrode terminal 50, a first sealing coating f1 is sandwiched between the terminal gasket 54 and the bottom 52 of the battery casing H. The first sealing coating f1 is pre-formed on the bottom 52 and the through hole 53 of the battery casing H before the electrode terminal 50 is disposed in the through hole 53.

[0209] Optionally, to enhance the sealing of the electrode terminal 50, a second sealing coating f2 covers the external exposed interface between the terminal gasket 54 and the bottom 52 of the battery casing H, and / or the external exposed interface between the connecting component 50c3 and the terminal gasket 54. The second sealing coating f2 is formed by spraying after the electrode terminal 50 is installed.

[0210] Those skilled in the art should understand that, in this invention, the first sealing coating f1 and / or the second sealing coating f2 are not essential requirements, but rather optional requirements.

[0211] The first sealing coating f1 and / or the second sealing coating f2 described above are made of materials with excellent sealing properties and resistance to electrolytes. Silicone resin, silicone acrylate, or polyamide-imide can be used as materials for the sealing coatings f1 and f2, but the present invention is not limited thereto.

[0212] The electrode terminal 50 fixing structure of the above-described embodiment of the present invention can be applied to cylindrical batteries.

[0213] Preferably, the cylindrical battery is, for example, a cylindrical battery with a shape factor value (defined as the diameter of the cylindrical battery divided by its height) that is approximately greater than 0.4.

[0214] Here, the shape factor refers to a numerical sequence representing the diameter and height of the cylindrical battery. One embodiment of the cylindrical battery of this invention includes, for example, the 46110 battery, 4875 battery, 48110 battery, 4880 battery, and 4680 battery. In the shape factor values, the first two digits represent the diameter of the battery, and the remaining digits represent the height of the battery.

[0215] One embodiment of the present invention is a generally cylindrical battery with a diameter of approximately 46 mm, a height of approximately 110 mm, and a shape factor of 0.418.

[0216] Another embodiment of the battery is a cylindrical battery in a generally cylindrical shape, with a diameter of approximately 48 mm, a height of approximately 75 mm, and a shape factor of 0.640.

[0217] Another embodiment of the battery is a cylindrical battery in a generally cylindrical shape, with a diameter of approximately 48 mm, a height of approximately 110 mm, and a shape factor of 0.436.

[0218] Another embodiment of the battery is a cylindrical battery in a generally cylindrical shape, with a diameter of approximately 48 mm, a height of approximately 80 mm, and a shape factor of 0.600.

[0219] Another embodiment of the battery is a cylindrical battery in a generally cylindrical shape, with a diameter of approximately 46 mm, a height of approximately 80 mm, and a shape factor of 0.575.

[0220] Previously, batteries with a form factor of approximately 0.4 or less were used. For example, 1865 and 2170 batteries were previously used. In the case of an 1865 battery, its diameter is approximately 18 mm, its height is approximately 65 mm, and its form factor is 0.277. In the case of a 2170 battery, its diameter is approximately 21 mm, its height is approximately 70 mm, and its form factor is 0.300.

[0221] Figure 8 This is a cross-sectional view of a cylindrical battery 70 of an embodiment of the present invention cut along a plane including the axial direction Y and the radial direction Z.

[0222] Reference Figure 8 The cylindrical battery 70 of the embodiment includes a gel roll type electrode assembly 71, which is formed by rolling up a sheet-like first electrode and a second electrode with a separation membrane sandwiched between them. The uncoated portion 72 of the first electrode is exposed at the bottom and the uncoated portion 73 of the second electrode is exposed at the top.

[0223] In this embodiment, the first electrode is a cathode and the second electrode is an anode. Of course, the opposite can also be true.

[0224] Method and reference for winding electrode assembly 71 Figure 2 The method of winding the electrode assembly used in the manufacturing of tabless cylindrical batteries described herein is essentially the same.

[0225] When illustrating the electrode assembly 71, only the uncoated portions 72 and 73 extending to the outside of the separation membrane are shown in detail; the winding structure of the first electrode, the second electrode, and the separation membrane is omitted from the illustration.

[0226] The cylindrical battery 70 also includes a cylindrical battery casing H that houses the electrode assembly 71 and is electrically connected to the uncoated portion 72 of the first electrode.

[0227] Preferably, one side (lower part) of the battery casing H is open. In addition, the bottom 52 of the battery casing H has a structure in which the electrode terminals 50 are riveted to the through hole 53 by a plugging process.

[0228] The cylindrical battery 70 also includes a terminal pad 54 sandwiched between the electrode terminal 50 and the through hole 53.

[0229] The cylindrical battery 70 also includes a sealing body 74 that seals the open end of the battery casing H to achieve insulation between the sealing body and the battery casing H. Preferably, the sealing body 74 includes a non-polarized cap 74a and a sealing gasket 74b sandwiched between the edge of the cap 74a and the open end of the battery casing H.

[0230] The cover 74a is made of conductive metals such as aluminum, steel, and nickel. The sealing gasket 74b is made of insulating and elastic materials such as polypropylene, polybutylene terephthalate, and polyvinyl fluoride. However, the present invention is not limited to the materials of the cover 74a and the sealing gasket 74b.

[0231] The cover 74a includes a vent 77 that breaks when the pressure inside the battery casing H exceeds a threshold. The vent 77 is formed on both sides of the cover 74a. The vent 77 is formed as a continuous or discontinuous circular pattern, linear pattern, or other pattern on the surface of the cover 74a.

[0232] The battery casing H includes a clamping part 75 that extends and bends inward toward the inside of the battery casing H to surround and secure the edge of the cover 74a together with the sealing gasket 74b.

[0233] The battery casing H also includes a rolled edge 76 pressed inwards in the region adjacent to the open end. The rolled edge 76 supports the edge of the sealing body 74 when the sealing body 74 is fixed by the clamping part 75, and in particular supports the outer peripheral surface of the sealing gasket 74b.

[0234] The cylindrical battery 70 also includes a first current collector 78 welded to the uncoated portion 72 of the first electrode. The first current collector 78 is made of a conductive metal such as aluminum, steel, or nickel. Preferably, at least a portion 78a of the edge of the first current collector 78 that does not contact the uncoated portion 72 of the first electrode is sandwiched between the rolled edge portion 76 and the sealing gasket 74b and fixed by the clamping portion 75. Alternatively, at least a portion 78a of the edge of the first current collector 78 is fixed to the inner peripheral surface 76a of the rolled edge portion 76 adjacent to the clamping portion 75 by welding.

[0235] The cylindrical battery 70 also includes a second current collector 79 welded to the uncoated portion 73 of the second electrode. Preferably, at least a portion of the second current collector 79, such as the central portion 79a, is welded to the flat portion D of the electrode terminal 50.

[0236] Preferably, when welding the second current collector 79, the welding tool is inserted through the hole 80 in the core of the electrode assembly 71 to reach the welding area of ​​the second current collector 79. Furthermore, when the second current collector 79 is welded to the flat portion D of the electrode terminal 50, the electrode terminal 50 supports the welding area of ​​the second current collector 79, thus applying stronger pressure to the welding area and improving welding quality. Additionally, the flat portion D of the electrode terminal 50 has a wide area, thus ensuring a wider welding area. This reduces the contact resistance of the welding area, thereby reducing the internal resistance of the cylindrical battery 70. The face-to-face welding structure of the riveted electrode terminal 50 and the second current collector 79 is very useful for rapid charging using a high charge rate (c-rate) current. Because the current density per unit area can be reduced in the cross-section in the current flow direction, the heat generated in the current path can be reduced compared to conventional methods.

[0237] When welding the flat portion D of the electrode terminal 50 and the second current collector 79, any one of the following welding methods can be used: laser welding, ultrasonic welding, spot welding, and resistance welding. The area of ​​the flat portion D is adjusted according to the welding method, and is preferably 2 mm or more for welding strength and ease of welding process.

[0238] In one example, when the flat portion D and the second current collector 79 are welded by laser and the welded line is continuous or discontinuous in the form of an arc pattern, the diameter of the flat portion D is preferably 4 mm or more. When the diameter of the flat portion D meets this condition, the weld strength can be ensured, and there is no difficulty in inserting the laser welding tool into the hole 80 of the electrode assembly 71 to perform the welding process.

[0239] In another example, when the flat portion D and the second current collector 79 are welded by ultrasonic waves in a circular pattern, the diameter of the flat portion D is preferably 2 mm or more. When the diameter of the flat portion D meets this condition, the weld strength is ensured, and there is no difficulty in inserting the ultrasonic welding tool into the hole 80 of the electrode assembly 71 to perform the welding process.

[0240] The cylindrical battery 70 also includes an insulator 80. The insulator 80 is sandwiched between the second current collector 79 and the outer surface 52a of the bottom 52, and between the inner peripheral surface 51a of the battery casing H sidewall and the electrode assembly 71. Preferably, the insulator 80 includes a welding hole 80a that exposes the flat portion D of the electrode terminal 50 to the side of the second current collector 79, covering the surface of the second current collector 79 and one side (upper) edge of the electrode assembly 71.

[0241] Preferably, the uncoated portions 72 and 73 of the first electrode and / or the second electrode are bent from the outer periphery of the electrode assembly 71 toward the core, thereby forming bending surfaces at the upper and lower parts of the electrode assembly 71. Additionally, the first current collector 78 is welded to the bending surface formed by bending the uncoated portion 72 of the first electrode, and the second current collector 79 is welded to the bending surface formed by bending the uncoated portion 73 of the second electrode.

[0242] To alleviate the stress generated when the uncoated portions 72 and 73 are bent, the first electrode and / or the second electrode have the same characteristics as conventional electrodes (see reference). Figure 1 Different improved structures.

[0243] Figure 17 This is a top view illustrating the structure of an electrode 90 according to a preferred embodiment of the present invention.

[0244] Reference Figure 17 The electrode 90 includes a sheet-shaped electrode current collector 91 made of a conductive foil material, an active material layer 92 formed on at least one side of the electrode current collector 91, and an uncoated portion 93 at the long side end of the electrode current collector 91 where no active material is coated.

[0245] Preferably, the uncoated portion 93 includes a plurality of slotted segments 93a. The plurality of segments 93a form multiple groups, and the segments 93a belonging to each group have the same height (length in the Y direction) and / or width (length in the X direction) and / or spacing. The number of segments 93a belonging to each group may be increased or decreased compared to the number shown in the figure. The segments 93a may be trapezoidal, or may be modified into quadrilaterals, parallelograms, semicircles, or semi-ellipses.

[0246] Preferably, the height of the cut piece 93a increases in stages as it moves from the core side toward the outer periphery. Furthermore, the uncoated portion 93' on the core side adjacent to the core side does not include the cut piece 93a, and the height of the uncoated portion 93' on the core side is less than the height of other uncoated portion areas.

[0247] Optionally, electrode 90 includes an insulating coating 94 covering the boundary between the active material layer 92 and the uncoated portion 93. The insulating coating 94 comprises an insulating polymer resin and optionally also includes inorganic filter material. The insulating coating 94 prevents the end of the active material layer 92 from contacting an active material layer of opposite polarity that is opposed by the separation membrane, structurally supporting the bending of the section 93a. Therefore, when electrode 90 is wound as an electrode assembly, it is preferable that at least a portion of the insulating coating 94 is exposed to the outside from the separation membrane.

[0248] Figure 18It is a cross-sectional view of an electrode assembly 100 that applies the segmented structure of the uncoated portion of the electrode 90 of the embodiment of the present invention to the first electrode and the second electrode by cutting along a plane including the axial direction Y and the radial direction Z.

[0249] Reference Figure 18 By reference Figure 2 The electrode assembly 100 is manufactured using a winding method as described herein. For ease of explanation, the protruding structures of the uncoated portions 72 and 73 extending outward from the separation membrane are shown in detail, while the winding structures of the first electrode, the second electrode, and the separation membrane are omitted from the illustration. The downward-protruding uncoated portion 72 extends from the first electrode, and the upward-protruding uncoated portion 73 extends from the second electrode.

[0250] A schematic illustration shows the pattern of height variation of the uncoated portions 72 and 73. That is, the height of the uncoated portions 72 and 73 varies irregularly depending on the position of the cut section. For example, when the side portion of the trapezoidal section 93a is cut, the height of the uncoated portion on the section is lower than the height of section 93a. Therefore, the heights of the uncoated portions 72 and 73 illustrated in the drawing showing the cross-section of the electrode assembly 100 correspond to the average height of the uncoated portions included in each winding coil.

[0251] like Figure 19 As shown, the uncoated portions 72 and 73 bend from the outer periphery of the electrode assembly 100 toward the core side. Figure 18 In the diagram, the bent portion 101 is indicated by a dashed box. When the uncoated portions 72 and 73 are bent, adjacent segments in the radial direction overlap to form multiple layers, creating bending surfaces 102 on the upper and lower parts of the electrode assembly 100. At this time, the uncoated portion on the core side ( Figure 17 The height of the 93' section decreases without bending, and the height h of the innermost bent section is less than or equal to the length r in the radial direction of the winding area formed by the uncoated portion 93' of the core without the section structure. Therefore, the cavity 80 in the core of the electrode assembly 100 is not closed by the bent section. When the cavity 80 is not closed, there is no difficulty in the electrolyte injection process, improving the electrolyte injection efficiency. In addition, the electrode terminal 50 and the second current collector 79 can be easily welded by inserting a welding tool through the cavity 80.

[0252] In the cylindrical battery 70 of this embodiment, the cover 74a of the sealing body 74 is not polarized. Instead, the first current collector 78 is connected to the side wall of the battery casing H, thereby giving the outer surface 52a of the bottom 52 a polarity opposite to that of the electrode terminals 50. Therefore, when multiple units are connected in series and / or in parallel, wiring such as bus connections is performed in one direction of the cylindrical battery 70 using the outer surface 52a of the bottom 52 and the electrode terminals 50. This increases the number of units mounted in the same space, thereby improving energy density.

[0253] In the present invention, with respect to the anode active material coated on the anode and the cathode active material coated on the cathode, any active material known in the art can be arbitrarily used.

[0254] In one example, the anode active material may include an alkaline metal compound represented by the general chemical formula A[A x M y O 2+z (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; 0 ≤ x, 1 ≤ x + y ≤ 2, -0.1 ≤ z ≤ 2; the stoichiometric coefficients of the components included in x, y, z, and M are selected in such a way that the compound maintains electrical neutrality).

[0255] In another example, the anode active material may be an alkaline metal compound xLiM 1 O2-(1 - x)Li2M 2 O3 (M 1 includes at least one element having an average oxidation state of 3; M 2 includes at least one element having an average oxidation state of 4; 0 ≤ x ≤ 1).

[0256] In yet another example, the anode active material is of the general chemical formula LiaM 1 x Fe 1-x M 2 yP 1-y M 3 zO 4-z (M 1 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 includes a halogen element optionally including F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; the stoichiometric coefficients of the components included in a, x, y, z, M 1 、M 2 、and M 3The stoichiometric coefficients of the components in the solution) or Li3M2(PO4)3 [M includes at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg and Al] represent lithium metal phosphates.

[0257] Preferably, the anolyte may include primary particles and / or secondary particles formed by the aggregation of primary particles.

[0258] In one example, the cathode active material can be carbon, lithium metal or lithium metal compounds, silicon or silicon compounds, tin or tin compounds, etc. Metal oxides such as TiO2 and SnO2 with a potential less than 2V can also be used as cathode active materials. Low-crystallinity carbon and high-crystallinity carbon can be used as carbon materials.

[0259] The separation membrane can be a porous polymer film, such as a porous polymer film made of polyolefin polymers such as ethylene monomer polymers, propylene monomer polymers, ethylene / butene copolymers, ethylene / hexene copolymers, and ethylene / methacrylate copolymers, or they can be used in layers. As another example, the separation membrane can be made of common porous nonwoven fabrics, such as nonwoven fabrics made of high-melting-point glass fibers or polyethylene terephthalate fibers.

[0260] At least one surface of the separation membrane may include a coating of inorganic particles. Furthermore, the separation membrane itself may be composed of a coating of inorganic particles. The particles constituting the coating may have a structure bonded to a binder, resulting in an interstitial volume between adjacent particles.

[0261] Inorganic particles can be composed of inorganic materials with a dielectric constant of 5 or higher. As a non-limiting example, the aforementioned inorganic particles may include those selected from Pb(Zr, Ti)O3 (PZT), Pb... 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb) 2 / 3 At least one substance in the group consisting of O3PbTiO3(PMN-PT), BaTiO3, hafnia(HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0262] Electrolytes can be those with A + B - Salts with similar structures. Among them, A... + Including Li + Na + K +Ions consisting of basic metal cations or combinations thereof. And B - For the choice of F - Cl - ,Br - I - NO3 - NCN2 - BF4 - ClO4 - AlO4 - AlCl4 - PF6 - SbF6 - AsF6 - BF2C2O4 - BC4O8 - CF 32 PF4 - CF 33 PF3 - CF 34 PF2 - CF 35 PF - CF 36 P - CF3SO3 - C4F9SO3 - CF3CF2SO3 - CF3SO 22 N - FSO 22 N - CF3CF2CF 32 CO - CF3SO 22 CH - SF 53 C - CF3SO 23 C - CF3CF 27 SO3 - CF3CO2 - CH3CO2 - SCN - and CF3CF2SO 22 N - Any one or more anions that make up the group.

[0263] Electrolytes can also be used in organic solvents. Suitable organic solvents include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or mixtures thereof.

[0264] The cylindrical battery described in the above embodiment can be used to manufacture battery packs.

[0265] Figure 20 This is a diagram that schematically illustrates the structure of a battery pack according to an embodiment of the present invention.

[0266] Reference Figure 20 The battery pack 200 of this embodiment includes an assembly that electrically connects cylindrical batteries 201 and a housing 202 that houses them. The cylindrical battery 201 is the battery of the above embodiment. In the accompanying drawings, for ease of illustration, components such as the busbar, cooling unit, and external terminals that electrically connect the cylindrical batteries 201 are omitted from the drawings.

[0267] The battery pack 200 can be installed in a vehicle. The vehicle can be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle can be a four-wheeled vehicle or a two-wheeled vehicle.

[0268] Figure 21 It is used for including Figure 20 The diagram illustrates the battery pack of a 200 car.

[0269] Reference Figure 21 An embodiment of the present invention, a vehicle V, includes a battery pack 200 according to an embodiment of the present invention. The vehicle V receives power from the battery pack 200 according to an embodiment of the present invention to operate.

[0270] The above embodiments are merely illustrative in all respects, and the invention is not limited thereto. The scope of the invention is further defined by the claims described below. Furthermore, all modifications and variations derived from equivalent concepts of the claims are included within the scope of the invention.

[0271] As described above, the present invention has been illustrated with reference to the accompanying drawings. However, the present invention is not limited to the embodiments and drawings disclosed in this specification, and those skilled in the art can make various modifications within the scope of the technical concept of the present invention. Furthermore, although the effects of the structure of the present invention have not been explicitly stated in the above description of the embodiments, the predictable effects derived from this structure should be acknowledged.

Claims

1. A fixing structure for electrode terminals, comprising: The battery casing has an open end on a first side and a bottom with a through hole on the opposite side. The bottom has a first surface and a second surface opposite to the first surface. Electrode terminals, which are fixed to the aforementioned bottom; and A terminal gasket, sandwiched between the aforementioned electrode terminal and the bottom. The aforementioned electrode terminals include: The neck has a cross-section smaller than that of the aforementioned through hole and is inserted into the aforementioned through hole; The head is connected to one end of the neck and has a cross-section larger than that of the through hole, and extends along the first surface of the bottom. A protrusion, which is connected to the other end of the neck, extends from the second surface of the bottom along the axial direction of the battery casing; The enlarged portion extends from the aforementioned protrusion in the centrifugal direction; and The front end face is located at the axial end of the aforementioned protrusion and is welded to the current collector. The aforementioned enlarged diameter portion is a connecting component that is physically attached to the outer peripheral surface of the aforementioned protrusion. The first surface is the outer surface of the bottom, and has a polarity opposite to that of the electrode terminals. The aforementioned front end face protrudes further in the aforementioned axial direction than the aforementioned connecting member between the outer peripheral surfaces of the aforementioned enlarged diameter portion and the aforementioned protrusion.

2. The electrode terminal fixing structure according to claim 1, wherein, The outer peripheral surface of the aforementioned protrusion has a connecting groove formed along the circumferential direction and recessed in the centripetal direction. The aforementioned connecting component is inserted into the aforementioned connecting groove and thus secured.

3. The electrode terminal fixing structure according to claim 2, wherein, The aforementioned connecting groove is in the shape of an external thread, and the aforementioned connecting component is a nut having an internal thread that connects with the aforementioned external thread.

4. The electrode terminal fixing structure according to claim 2, wherein, The aforementioned connecting groove is an O-shaped groove, and the aforementioned connecting component is a C-shaped ring inserted into the aforementioned O-shaped groove.

5. The electrode terminal fixing structure according to claim 2, wherein, The surface of the connecting component facing the bottom includes a sidewall surface that gradually moves away from the bottom as it approaches the outer side in the radial direction.

6. The electrode terminal fixing structure according to claim 5, wherein, When the connecting component is engaged with the connecting groove, the terminal pad is pressed against the bottom of the battery casing by the side wall surface.

7. The electrode terminal fixing structure according to claim 1, wherein, Also includes: A first sealing coating is formed at the interface between the terminal gasket and the bottom of the battery casing.

8. The electrode terminal fixing structure according to claim 7, wherein, The aforementioned first sealing coating includes silicone resin, silicone acrylate, or polyamide imide.

9. The electrode terminal fixing structure according to claim 1, further comprising: The second sealing coating covers the external exposed interface between the aforementioned connecting component and the aforementioned terminal gasket.

10. The electrode terminal fixing structure according to claim 9, wherein, The second sealing coating covers the external exposed interface between the terminal gasket and the bottom.

11. The electrode terminal fixing structure according to claim 9 or 10, wherein, The aforementioned second sealing coating includes silicone resin, silicone acrylate, or polyamide imide.

12. The electrode terminal fixing structure according to claim 1, wherein, With the bottom surface of the battery casing as a reference, the front end face protrudes further than the enlarged diameter portion in the axial direction of the battery casing.

13. The electrode terminal fixing structure according to claim 1, wherein, The aforementioned front end surface includes a flat portion with a flat surface.

14. The electrode terminal fixing structure according to claim 1, wherein, The aforementioned connecting component has a first section that extends from the aforementioned protrusion in a centrifugal direction and gradually moves away from the bottom of the aforementioned battery casing.

15. The electrode terminal fixing structure according to claim 14, wherein, In the first interval mentioned above, the angle formed between the surface of the connecting member facing the bottom and the bottom exceeds 0 degrees and is less than 60 degrees.

16. The electrode terminal fixing structure according to claim 1, wherein, In the aforementioned enlarged section, the diameter of the cross-section cut along a direction perpendicular to the central axis of the battery casing is larger than the diameter of the aforementioned through hole.

17. The electrode terminal fixing structure according to claim 1, wherein, In the aforementioned expanded diameter section, the diameter of the cross-section cut along a direction perpendicular to the central axis of the battery casing gradually increases as it moves away from the bottom of the battery casing.

18. The electrode terminal fixing structure according to claim 1, wherein, The portion of the terminal pad sandwiched between the head and the bottom of the battery casing is in a crimped state.

19. A battery comprising: An electrode assembly is formed by winding a first electrode and a second electrode together with a separation membrane sandwiched between them, and includes an uncoated portion of the first electrode and an uncoated portion of the second electrode extending from both ends and protruding to the outside of the separation membrane. and The battery casing has an open end on a first side, through which the electrode assembly is housed and electrically connected to the first electrode, and has a bottom with a through hole on the other side opposite to the first side, the bottom having a first surface and a second surface opposite to the first surface; An electrode terminal, which is provided through the through hole without contacting the inner wall of the through hole formed in the bottom of the battery casing, and is electrically connected to the second electrode, includes: a neck having a cross-section smaller than that of the through hole and inserted into the through hole; a head connected to one end of the neck and having a cross-section larger than that of the through hole, and extending along the first surface of the bottom; a protrusion connected to the other end of the neck and extending from the second surface of the bottom along the axial direction of the battery casing; an enlarged diameter portion extending from the protrusion in the centrifugal direction; and a front end face provided at the axial end of the protrusion and welded to the current collector, wherein the enlarged diameter portion is a connecting member physically bonded to the outer peripheral surface of the protrusion; Terminal gaskets, sandwiched between the electrode terminals and the through holes; and A sealing body that seals the open end of the battery casing to insulate it from the battery casing. The first surface is the outer surface of the bottom, and has a polarity opposite to that of the electrode terminals. The aforementioned front end face protrudes further in the aforementioned axial direction than the aforementioned connecting member between the outer peripheral surfaces of the aforementioned enlarged diameter portion and the aforementioned protrusion.

20. The battery according to claim 19, wherein, The outer peripheral surface of the aforementioned protrusion has a connecting groove formed along the circumferential direction and recessed in the centripetal direction. The aforementioned connecting component is inserted into the aforementioned connecting groove and fixed in place.

21. The battery according to claim 20, wherein, The aforementioned connecting groove is in the shape of an external thread, and the aforementioned connecting component is a nut having an internal thread that connects with the aforementioned external thread.

22. The battery according to claim 20, wherein, The aforementioned connecting groove is an O-shaped groove, and the aforementioned connecting component is a C-shaped ring inserted into the aforementioned O-shaped groove.

23. The battery according to claim 20, wherein, The surface of the connecting component facing the bottom includes a sidewall surface that gradually moves away from the bottom as it approaches the outer side in the radial direction.

24. The battery according to claim 23, wherein, When the connecting component is engaged with the connecting groove, the side wall surface presses the terminal pad against the bottom of the battery casing.

25. The battery according to claim 19, wherein, Also includes: A first sealing coating is formed at the interface between the terminal gasket and the bottom of the battery casing.

26. The battery according to claim 25, wherein, The aforementioned first sealing coating includes silicone resin, silicone acrylate, or polyamide imide.

27. The battery according to claim 19, further comprising: The second sealing coating covers the external exposed interface between the aforementioned connecting component and the aforementioned terminal gasket.

28. The battery according to claim 27, wherein, The second sealing coating covers the external exposed interface between the terminal gasket and the bottom.

29. The battery according to claim 27 or 28, wherein, The aforementioned second sealing coating includes silicone resin, silicone acrylate, or polyamide imide.

30. The battery according to claim 19, wherein, The battery casing includes a rolled edge that is pressed inwards in the region adjacent to the open end. The aforementioned sealing body includes a non-polar cap and a sealing gasket sandwiched between the edge of the cap and the open end of the battery casing.

31. The battery according to claim 30, wherein, The battery casing further includes a clamping part that extends and bends inward toward the inside of the battery casing, and together with the sealing gasket, surrounds the edge of the cover and secures it.

32. The battery according to claim 31, wherein, Also includes: The first current collector is bonded to the uncoated portion of the first electrode. At least a portion of the edge of the first current collector that does not contact the uncoated portion of the first electrode is sandwiched between the rolled edge and the sealing gasket and is fixed by the clamping portion.

33. The battery according to claim 32, wherein, At least a portion of the edge of the first current collector is fixed to the inner circumferential surface of the rolled edge portion adjacent to the clamping portion by welding.

34. The battery according to claim 19, wherein, Also includes: The second current collector is bonded to the uncoated portion of the second electrode. At least a portion of the second current collector is welded to the front end face of the electrode terminal.

35. The battery according to claim 34, wherein, Also includes: An insulator sandwiched between the second current collector and the bottom inner circumferential surface of the battery casing, and between the inner circumferential surface of the side wall of the battery casing and the electrode assembly.

36. The battery according to claim 19, wherein, The shape factor of the battery's diameter divided by its height is greater than 0.

4.

37. The battery according to claim 19, wherein, The AC resistance measured through the electrode terminals of the battery and the outer surface of the bottom of the battery casing is less than 4 milliohms.

38. A battery pack comprising a plurality of batteries according to any one of claims 19 to 37.

39. An automobile comprising the battery pack according to claim 38.

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