Battery cell and battery pack vehicule including the same

Abstract

Provided is a cylindrical battery cell having a simple structure, a simple assembly process, and high energy density. An electrode assembly is accommodated in an accommodation space of a can of the battery cell. One electrode of the electrode assembly is bonded to an end wall provided at a lower end portion of the can, and the other electrode of the electrode assembly is bonded to a cap covering an opening provided at an upper end portion of the can. The bonding is performed by irradiating a laser to the end wall and an outer surface of the cap to penetrate and weld the end wall and the outer surface of the cap. A first current collecting plate including a radially extending portion and an axially extending portion is interposed between the cap and the electrode assembly. The radially extending portion is bonded to a first electrode of the electrode assembly, and an upper end portion of the axially extending portion is bonded to a bottom surface of the cap.

Description

cylindrical battery cells

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0076876, filed June 13, 2024, and Korean Patent Application No. 10-2025-0053631, filed April 24, 2025, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a cylindrical battery cell, and more particularly, to a cylindrical battery cell having a simple structure, a simple assembly process, and a high energy density.

[0003] With the proliferation of electric vehicles, the capacity of cylindrical battery cells, manufactured using cylindrical battery cans as housings, is increasing. Because these cylindrical battery cells have a large energy capacity per cell, they require further reduction in internal resistance. Furthermore, high energy density is desirable to enhance vehicle installation.

[0004] Conventionally, as illustrated in FIG. 1, a first collector plate (30) is welded to the axial first end of a cylindrical jelly-roll-shaped electrode assembly (20) to electrically connect the first collector plate (30) and the first electrode of the electrode assembly (20), and the first collector plate (30) is welded to a rivet terminal (17) fixed to the axial end wall (12) of the can (10), to electrically connect the first electrode of the electrode assembly (20) and the rivet terminal (17).

[0005] In addition, when welding the first collector plate (30) and the rivet terminal (17), ultrasonic welding was performed by inserting a thin and long welding horn tip through the core cavity (29) of the electrode assembly (20).

[0006] However, spatter that may occur during the ultrasonic welding process may damage the separator, which may reduce battery capacity and lifespan. In addition, since there is a limit to how thin and long the welding horn tip can be, there is a limit to reducing the diameter of the core cavity (29) of the electrode assembly (20), which makes it difficult to increase the energy density of the battery cell.

[0007] In addition, since the first collector plate (30) and the first end wall (12) have different polarities, an insulator (19) is interposed between them to provide electrical insulation, but the insulator (19) also occupies the internal space of the can (10), making it difficult to increase the energy density.

[0008] In addition, the shape of the second collector plate (40) connected to the second electrode of the electrode assembly (20) is complex, and it is difficult to reduce the cost due to the hassle of assembling it together with the cap (50).

[0009] The present invention has been derived to solve the above-described problem, and aims to provide a battery cell having a structure in which there is no concern that welding by-products will remain inside the can when welding a first collector plate and a first electrode terminal.

[0010] The present invention aims to provide a battery cell having a simple component shape and a simple assembly process, thereby reducing production costs.

[0011] The present invention seeks to provide a battery cell having a higher energy density.

[0012] The technical objectives of the present invention are not limited to the purposes mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0013] The present invention, which aims to solve the above-described problem, manufactures a battery cell by accommodating an electrode assembly in a can receiving space, bonding one electrode of the electrode assembly to an end wall provided at a lower end of the can, and bonding another electrode of the electrode assembly to a cap covering an opening provided at an upper end of the can.

[0014] The connection between the end wall and the electrode can be achieved by penetration welding on the outer surface of the end wall.

[0015] The connection between the cap and the electrode can be made by penetration welding on the outer surface of the cap.

[0016] The above penetration welding can be performed by irradiating the outer surface with a laser.

[0017] The above electrode assembly may be in the form of a cylindrical jelly-roll in which the first electrode and the second electrode, each coated with an active material, are wound around a core with a separator interposed therebetween.

[0018] In the first electrode of the above electrode assembly, the non-coated portion of the electrode assembly may be bent radially at the axial first end of the electrode assembly to provide a first surface substantially intersecting the axial direction.

[0019] In the second electrode of the electrode assembly, the non-coated portion of the electrode assembly may be bent radially at the axial second end of the electrode assembly to provide a second surface substantially intersecting the axial direction.

[0020] The can has a side wall extending axially and surrounding an internal space in a circumferential direction, an opening provided at an axial first end of the side wall, and an end wall connected to an axial second end of the side wall and extending radially to cover the internal space.

[0021] The above end wall can be integrally connected to the side wall.

[0022] The above end wall and side wall can be formed as a single unit in a monolithic form.

[0023] The first collector plate is joined to the axial first end of the electrode assembly so as to be electrically connected to the first electrode.

[0024] The first collector plate has an axial extension portion extending in the axial direction and having a hole extending axially, and a radial extension portion extending radially from the axial extension portion and joined to the axial first end of the electrode assembly.

[0025] In some examples, the axial extension may be in the form of a center tube having an axially extending center hole.

[0026] In some examples, the axial extension portion has an axially penetrating hole, and the hole can communicate with the core cavity of the electrode assembly.

[0027] In some examples, the radial extension may be connected to an axial lower end of the axial extension.

[0028] In some examples, the radial extension may extend radially outward from the axial extension.

[0029] In some examples, the radial extension may be joined to a tab of the first electrode provided at the axial first end of the electrode assembly.

[0030] In some examples, the axial extension may be joined to the cap by a first weld welded through from the outer surface of the cap.

[0031] The second electrode may be electrically connected to the end wall.

[0032] The second electrode may be bonded to the end wall.

[0033] The second electrode can be electrically connected to the end wall by a second weld formed by penetrating welding from the outer surface of the end wall.

[0034] The second collector plate can be joined to the axial second end of the electrode assembly so as to be electrically connected to the second electrode.

[0035] The above second collector plate may be in the shape of a flat disk.

[0036] The axial inner surface of the second collector plate can be bonded to the second surface provided by the non-conductive portion of the second electrode of the electrode assembly.

[0037] The above electrode assembly is accommodated in the internal space of the can.

[0038] The axial second end of the above electrode assembly faces the end wall.

[0039] The axial outer surface of the second collector plate joined to the axial second end of the electrode assembly can be in contact with the end wall.

[0040] The second electrode of the electrode assembly and the end wall of the can can be joined by a second welded portion that penetrates the end wall to the axial second end of the electrode assembly.

[0041] The second welding portion extends through the end wall and to the axial outer surface of the second collector plate, thereby joining the second collector plate to the end wall.

[0042] Insulating tape may be attached to the edge of the above radial extension and the corner portion of the upper edge of the first collector plate.

[0043] The above insulating tape can be attached to the upper surface of the edge of the radial extension and the outer surface of the axial first end of the circumferential surface of the electrode assembly.

[0044] An electrolyte can be injected into the space of the can containing the electrode assembly.

[0045] The electrolyte is injected through the opening, and at least a portion of the injected electrolyte flows into the bottom of the can through the hole of the axial extension of the first collector plate and can impregnate the electrode assembly.

[0046] In some examples, the side wall of the can may be provided with a beaded portion in which the side wall is recessed radially inward between an axial first end of the side wall and an axial first end of an electrode assembly accommodated in the interior space of the can.

[0047] The above beading portion may be in contact with or adjacent to the electrode assembly with the insulating tape interposed therebetween.

[0048] The side wall of the can may be provided with a crimping portion formed so that the axial first end extends radially inward. The cap may have its edge positioned axially between the beading portion and the crimping portion.

[0049] The edge of the above cap can be positioned between the beading portion and the crimping portion in the axial direction and pressed in the axial direction.

[0050] The edge of the above cap can be pressed and fixed by the beading portion and the crimping portion while the gasket is interposed.

[0051] Accordingly, the cap can be sealed and fixed to the first end of the side wall of the can.

[0052] The above cap is joined to the first collector plate by a first welding portion.

[0053] The first welding portion extends to the axial upper end of the axial extension portion that penetrates the cap and contacts the bottom surface of the cap, thereby joining the first collector plate to the cap.

[0054] The cap may constitute a first electrode terminal electrically connected to a first electrode of the electrode assembly, and the can may constitute a second electrode terminal electrically connected to a second electrode of the electrode assembly.

[0055] The above crimping portion can provide a flat surface facing the axial outer side.

[0056] The central portion of the cap may protrude further axially outward than its edge and may provide a flat surface facing axially outward.

[0057] The height of the central surface of the cap may correspond to or be slightly higher than the height of the surface of the crimping portion.

[0058] The central surface of the cap may provide a surface to which a bus bar of the first polarity may be joined, and the surface of the crimping portion may provide a surface to which a bus bar of the second polarity may be joined.

[0059] In some examples, the edge of the cap and the edge of the side wall may be seam welded.

[0060] The cap has a central portion and a peripheral portion that are electrically insulated from each other, and the axial extension portion can be welded to the lower surface of the central portion.

[0061] The central surface of the cap may provide a surface to which a bus bar of the first polarity may be joined, and the peripheral surface may provide a surface to which a bus bar of the second polarity may be joined.

[0062] The present invention provides a battery pack having a pack case that houses the battery cell.

[0063] The battery cell may be embedded in the pack case such that the end wall is in contact with the bottom of the pack case and the cap faces upward.

[0064] A cooling structure for cooling the battery cell through the end wall of the battery cell may be provided at the bottom of the pack case.

[0065] The present invention provides a vehicle equipped with a battery pack and driven by power from the battery pack.

[0066] In the battery cell of the present invention, the welding of the current collector plate and the electrode terminal is performed both on the outside of the can through laser penetration welding, and the welding is not performed in the internal space of the battery can, so there is no concern that welding byproducts will affect the performance of the battery cell.

[0067] Additionally, since the horn tip for ultrasonic welding does not need to be inserted through the hollow portion of the electrode assembly, the inner diameter of the hollow portion of the electrode assembly can be minimized. This can increase the energy density of the battery cell.

[0068] The battery cell of the present invention can reduce production costs by omitting rivet terminals and insulator parts and reducing assembly work.

[0069] Additionally, the electrode assembly can be made larger by omitting the space for the riveted terminals and insulator, thereby increasing the energy density of the battery cell.

[0070] The battery cell of the present invention has a larger area of ​​the first electrode terminal formed by the cap compared to the rivet terminal, which is advantageous for welding the bus bar.

[0071] The battery cell of the present invention has both the first electrode terminal and the second electrode terminal exposed upward, so that cooling of the battery cell through the bottom is possible, and the electrode assembly is in close contact with the bottom of the can, so that the bottom cooling efficiency is high.

[0072] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0073] Figure 1 is a cross-sectional view showing a comparative form of a cylindrical battery cell.

[0074] Figure 2 is an exploded perspective view of the electrode assembly accommodated inside the can of Figure 1 before winding.

[0075] Fig. 3 is a perspective view of the electrode assembly of Fig. 2 in a pre-winding laminated state.

[0076] Fig. 4 is a perspective view of an assembled cylindrical jelly-roll-shaped electrode assembly by winding up the laminate of Fig. 3.

[0077] Figure 5 is a perspective view showing a state in which a first collector plate is joined to an electrode tab provided at an axial first end of an electrode assembly facing the opening of a can.

[0078] Figure 6 is a perspective view showing a state in which a second collector plate is joined to an electrode tab provided on a second axial end of an electrode assembly facing the end wall of a can.

[0079] Fig. 7 is a perspective view showing a state in which an insulator in the form of an insulating tape is attached to the corner portion of the first collector plate and electrode assembly of Fig. 5.

[0080] Figure 8 is a perspective view showing the electrode assembly of Figure 7 inserted into a can.

[0081] FIG. 9 is a cross-sectional view showing a state in which the electrode assembly is inserted into the can as illustrated in FIG. 8, with the second collector plate in contact with the end wall and the first collector plate positioned toward the opening inside the can.

[0082] Fig. 10 is a cross-sectional view showing a state in which a second collector plate is welded to the end wall of the can of Fig. 9 by penetrating welding the end wall with a laser.

[0083] Fig. 11 is a bottom view of the can of Fig. 10.

[0084] Figure 12 is a cross-sectional view showing the process of beading the upper part of the can of Figure 10 and injecting electrolyte through the first collector plate.

[0085] Figure 13 is a cross-sectional view showing a state in which the opening of the can is sealed by covering the opening of the can with a cap and forming a crimping portion after the electrolyte of Figure 12 is injected.

[0086] Fig. 14 is a cross-sectional view showing a state in which the cap and the first collector plate are welded by penetrating welding the cap of Fig. 13 with a laser.

[0087] Figure 15 is a plan view of the can of Figure 14.

[0088] Fig. 16 is a perspective view of the can of Fig. 14.

[0089] Fig. 17 is a cross-sectional view showing another embodiment, a process of injecting an electrolyte while the second collector plate of the electrode assembly is welded to the end wall of the can.

[0090] Figure 18 is a cross-sectional view showing the process of covering the opening of the can with a cap after injecting the electrolyte of Figure 17, deep-welding the cap and the can with a laser, and penetrating-welding the cap to the first collector plate.

[0091] Figure 19 is a schematic drawing of a battery pack having a battery cell of the embodiment built in.

[0092] Figure 20 is a schematic drawing of a vehicle equipped with the battery pack of Figure 19.

[0093] [Explanation of symbols]

[0094] 10: Can (housing) 11: Side wall 12: End wall 13: Beading part 14: Crimping part 17: Rivet terminal 170: Terminal gasket 19: Insulator 191: Surface part 192: Side part 20: Electrode assembly 21: First electrode (positive electrode) 22: Second electrode (negative electrode) 23: Metal foil 24: Active material layer 25: Supporting part 26: Non-coated part 27: Electrode tab (notched tab) 28: Separator 29: Core hollow part 30: Positive current collector (first current collector) 31: Radial extension 32: Electrode connection 33: Axial extension 34: Terminal connection 40: Negative current collector (second current collector) 50: Cap 51: Center part 52: Peripheral part 53: Insulating seal 55: Gasket W1, W2, W3: Welding 70: Battery pack 71: Pack case 72: Battery cell 80: Vehicle

[0095] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0096] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0097] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0098] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0099] Additionally, when it is described that a component is "connected," "coupled," or "contacted" with another component, it should be understood that the components may be directly connected or in contact with each other, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "contacted" through another component.

[0100] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0101] Throughout the specification, when we refer to "A and / or B", this means A, B, or A and B, unless otherwise stated, and when we refer to "C to D", this means C or more and D or less, unless otherwise stated.

[0102] In describing the embodiment, the axial direction refers to the direction in which the axis forming the winding center of the jelly-roll type electrode assembly extends, the radial direction refers to the direction closer to or farther from the axis, and the circumferential direction refers to the direction surrounding the axis.

[0103] [Cylindrical battery cell]

[0104] Referring to FIGS. 2 to 8, a cylindrical battery cell according to an embodiment of the present invention includes an electrode assembly (20), a current collector (30, 40) electrically connected to the electrode assembly (20), and a can (10) that accommodates the electrode assembly (20) and the current collector (30, 40).

[0105] The above electrode assembly (20) is manufactured in the form of a jelly-roll by preparing a first electrode (21), a second electrode (22), and a separator (28) that extend in the longitudinal direction with a predetermined width as shown in FIG. 2, and then forming a laminate by stacking the first electrode (21), the separator (28), the second electrode (22), and the separator (28) in that order as shown in FIG. 3, and then winding this around a core shaft as shown in FIG. 4.

[0106] The above first electrode (21) may be an anode, and the above second electrode (22) may be a cathode. Of course, the opposite may also be the case.

[0107] The above first electrode (21) and second electrode (22) are manufactured in the form of sheets. The electrode sheet is manufactured in the form of an active material layer (24) applied to the surface of a metal foil (23). The electrode sheet has a holding portion (25) region where the active material layer (24) is applied, and a non-coated portion (26) region where the active material layer (24) is not applied. The positive electrode sheet has a non-coated portion (26) region on one side in the width direction, and the negative electrode sheet has a non-coated portion (26) region on the other side in the width direction.

[0108] The non-conductive portion (26) is exposed or protrudes in the width direction of the laminate. The non-conductive portion (26) itself functions as an electrode tab (27).

[0109] In the above-mentioned blank portion (26), notches can be formed at a predetermined interval to form flag-shaped notching tabs (27).

[0110] In the embodiment, the notching tabs (27) are exemplified as having an equilateral trapezoidal shape. However, their shapes may be various, such as a semicircle, a semi-ellipse, a triangle, a rectangle, a parallelogram, etc.

[0111] In addition, in the embodiment, a form in which the notching tabs (27) arranged along the longitudinal direction have the same width is exemplified. However, the width of the notching tabs may be gradually or stepwise widened from the core side to the outer periphery side.

[0112] In addition, in the embodiment, a form in which the height of the notching tabs (27) gradually increases from the core side to the outer circumference side is exemplified. However, the height of these notching tabs may be implemented in a form in which they are constant or gradually decrease.

[0113] In addition, in the embodiment, a structure is exemplified in which a notching tab (27) is deleted in a predetermined section of the centrifugal end of the non-conductive portion (26) and a predetermined section of the centrifugal end. However, it is of course possible that the notching tab may not be deleted in the centrifugal end of the non-conductive portion, and that the notching tab may not be deleted in the centrifugal end of the non-conductive portion.

[0114] In the jelly roll-shaped electrode assembly (20), the notched tab (27) can be bent radially and flattened as illustrated in FIG. 4. The notched tab (27) can be bent radially inward or outward. In the embodiment, a structure in which the notched tab (27) is bent radially inward is exemplified.

[0115] The above-mentioned notched tabs (27) can be bent one by one during the process of forming a jelly roll-shaped electrode assembly (20) by winding the laminate. Alternatively, the above-mentioned notched tabs (27) can be bent all at once after the laminate is wound to form a jelly roll-shaped electrode assembly.

[0116] The notching tabs (27) of the first electrode (21) and the notching tabs (27) of the second electrode (22), which are bent and overlapped in the radial direction in this way, can provide a first plane and a second plane that are substantially perpendicular to the axial direction at the axial ends of the electrode assembly (20), respectively.

[0117] The first and second surfaces, which are substantially flat and provided by bending the notched tabs (27) exposed at both axial ends of the electrode assembly (20), can be joined with the first collector plate (30) and the second collector plate (40), as shown in FIGS. 5 and 6.

[0118] In the embodiment, the first collector plate (30) is exemplified as a positive collector plate and the second collector plate (40) is a negative collector plate. However, the first collector plate (30) may be a negative collector plate and the second collector plate (40) may be a positive collector plate.

[0119] The second collector plate (40) may include a copper material, and the first collector plate (30) may include an aluminum material. However, the materials are not limited thereto.

[0120] Referring to FIG. 5, the first collector plate (30) includes a terminal connection portion (34) provided in a portion corresponding to the hollow portion (29) of the core of the electrode assembly (20), and an electrode connection portion (32) provided in a form surrounding the terminal connection portion (34).

[0121] According to an embodiment, the first collector plate (30) may include an axial extension portion (33) that is aligned with the center of the hollow portion (29) of the electrode assembly (20) and extends axially, and a radial extension portion (31) that extends radially outward from an axial lower end of the axial extension portion (33). The axial extension portion (33) may be in a tube shape, and the radial extension portion may be in an annular plate shape.

[0122] The electrode connection portion (32) is provided in the radial extension portion (31). By irradiating a laser onto the surface of the radial extension portion (31), the radial extension portion (31) is penetratedly welded to the notched tab (27) of the first electrode (21) of the electrode assembly (20), thereby electrically connecting the first current collector plate (30) and the first electrode (21) of the electrode assembly (20). The welding line of the laser may extend radially.

[0123] An axially penetrating hole may be provided in the central portion of the axial extension portion (33). The inner diameter of the axial extension portion (33) may substantially correspond to the inner diameter of the hollow portion (29) of the electrode assembly (20) or may be slightly smaller than that. Accordingly, the injection of the electrolyte can be smoothly performed, and the phenomenon of the injected electrolyte striking the separator arranged around the hollow portion (29) of the electrode assembly (20) and causing the separator to unwind can be suppressed.

[0124] The terminal connection portion (34) is provided on the axial extension portion (33). The axial extension portion (33) may have a predetermined thickness to ensure sufficient rigidity in the axial direction. Since the axial extension portion (33) extends axially upward, the welding of the first collector plate (30) and the cap (50), which will be described later, can be performed more smoothly.

[0125] The above first collector plate (30) can be manufactured by manufacturing the axial extension portion (33) and the radial extension portion (31) as separate parts and then joining them.

[0126] Referring to Fig. 6, the second collector plate (40) may be in the shape of a disk. Accordingly, by irradiating a laser onto the surface of the second collector plate (40), the second collector plate (40) is penetratedly welded to the notched tab (27) of the second electrode (22) of the electrode assembly (20), thereby electrically connecting the second collector plate (40) and the second electrode (22) of the electrode assembly (20). The welding line of the laser may extend radially.

[0127] Referring to Fig. 7, an electrically insulating insulating tape (19) is attached to the upper portion of the electrode assembly (20), which has a surface portion (191) covering the edge portion of the upper surface of the electrode assembly (20) and a side portion (192) covering the upper edge portion of the peripheral surface of the electrode assembly (20). Accordingly, the insulating tape (19) can electrically insulate the notched tab (27) and the first collector plate (30) of the first electrode (21) of the electrode assembly (20) from the can (10).

[0128] Referring to FIGS. 8 and 9, the can (10) includes a side wall (11) extending axially between a first end and a second end, and an end wall (12) connected to the second end of the side wall (11) and extending radially. The first end of the side wall (11) is open to define an opening of the can (10).

[0129] The above end wall (12) may have a disc shape, and the side wall (11) may have a circular tube shape.

[0130] The above end wall (12) and side wall (11) can be manufactured by forming a metal sheet with a nickel plated surface using a deep drawing process, and trimming the end of the side wall (11) with a punch while holding it with a blank holder. Of course, the material of the can (10) is not limited to this.

[0131] The electrode assembly (20) is accommodated inside the can (10) through the opening while the second collector plate (40) is aligned so as to face the end wall (12) of the can (10). Accordingly, both surfaces of the flat second collector plate (40) are respectively interposed between the end wall (12) and the surfaces of the notched tabs (27) of the second electrode (22). The second collector plate (40) is in substantial surface contact with the surfaces of the notched tabs (27) of the second electrode (22) and also in surface contact with the end wall (12).

[0132] In addition, when the electrode assembly (20) is accommodated inside the can (10), the electrode tab (27) of the first electrode (21) and the first collector plate (30) are arranged to face the opening of the side wall (11). In addition, the side surface (192) of the insulating tape (19) electrically insulates the electrode tab (27) of the first electrode (21) and the first collector plate (30) from the side wall (11) of the can (10).

[0133] Referring to FIGS. 10 and 11, the second collector plate (40) is joined to the end wall (12) of the can (10). The joining may be thermal joining. The thermal joining may be, for example, welding. The welding may be performed by irradiating a laser (L) to the end wall (12) of the can (10) from the outside of the can (10). That is, the welding may be performed by penetrating welding the end wall (12) to the second collector plate (40).

[0134] To increase welding reliability and the welding area of ​​the weld (W1), the laser (L) may be scanned in a radial direction, preferably in a zigzag shape. In addition, the weld (W1) may be provided at multiple locations spaced apart at a predetermined angle in the circumferential direction.

[0135] The embodiment exemplifies a structure in which the second electrode (22) and the end wall (12) are electrically connected through the second collector plate (40). However, the second collector plate (40) may be omitted. That is, laser penetration welding may be performed as described above in a state in which the notched tab (27) bent radially inwardly of the second electrode (22) and the inner surface of the end wall (12) are in direct contact.

[0136] Referring to Fig. 12, in the first embodiment, after welding the second collector plate (40) and the end wall (12), a beading portion (13) can be formed near the opening-side end of the side wall (11) of the can (10). The axial lower portion of the beading portion (13) axially interferes with the surface portion (191) of the insulating tape (19) at the edge of the upper surface of the electrode assembly (20), thereby controlling the axial position of the electrode assembly (20). The surface portion (191) of the insulating tape (19) electrically insulates the electrode tab (27) of the first electrode (21) and the first collector plate (30) from the beading portion (13) of the side wall (11) of the can (10).

[0137] Of course, unlike the embodiment, the beading portion (13) may be processed first as shown in Fig. 12, and then the welding portion (W1) may be formed as shown in Fig. 10.

[0138] After forming the above welding portion (W1) and processing the beading portion (13), an electrolyte can be injected into the interior of the can (10) as illustrated in Fig. 12. The injection nozzle for injecting the electrolyte can be axially mounted on the upper surface of the beading portion (13). Alternatively, the injection nozzle can also be axially mounted on the upper surface of the axial extension portion (33).

[0139] At least a portion of the electrolyte can be impregnated into the interior of the electrode assembly (20) through a hole provided in the axial extension portion (33) of the first collector plate (30).

[0140] In this way, before covering the opening with a cap (50), an electrolyte can be injected into the interior of the can (10).

[0141] After injecting the electrolyte, the upper surface of the axial extension (33) of the first collector plate (30) can be cleaned if necessary.

[0142] When the filling is complete, the opening of the can (10) is sealed with a cap (50) as shown in Fig. 13. The cap (50) may be made of a metal plate. The cap (50) may be press-processed so that the center portion protrudes axially upward compared to the edges.

[0143] The edge of the cap (50) is placed on the beading portion (13) of the side wall (11) with the gasket (55) interposed therebetween, and the crimping portion (14) can be formed by crimping the first end of the side wall (11) radially inward. Accordingly, the lower surface, the outer circumferential surface, and the upper surface of the edge of the cap (50) are axially pressed by the beading portion (13) and the crimping portion (14) of the side wall (11) with the gasket (55) interposed therebetween.

[0144] Accordingly, the cap (50) and the can (10) are sealed and electrically insulated from each other.

[0145] Referring to FIGS. 14 and 15, the first collector plate (30) is bonded to the cap (50). The bonding may be thermal bonding. The thermal bonding may be, for example, welding. The welding may be performed by irradiating the cap (50) with a laser (L) from the outside of the can (10). That is, the welding may be performed by penetrating-welding the cap (50) to the upper surface of the axial extension (33) of the first collector plate (30).

[0146] In order to increase the welding reliability of the welded portion (W2), the upper surface of the axial extension portion (33) and the lower surface of the central portion of the cap (50) can be brought into close contact in the axial direction. In addition, the laser (L) can be scanned in the circumferential direction of a trajectory corresponding to the upper surface of the axial extension portion (33).

[0147] The cap (50) may have a first polarity, and the can (10) may have a second polarity. The gasket (55) is inserted so as to be pressed between the edge of the cap (50) and the can (10), thereby electrically insulating the cap (50) from the can (10) and sealing the gap between the cap (50) and the can (10). In one example, the first polarity may be a positive pole and the second polarity may be a negative pole. Of course, the opposite may also be the case.

[0148] Accordingly, as illustrated in FIG. 16, both the cap (50) and the crimping portion (14) may be positioned at the axial first end of the battery cell. Accordingly, both the bus bar connected to the first electrode terminal (50) of the battery cell and the bus bar connected to the second electrode terminal (14) may be positioned at the upper portion of the battery cell. Of course, the cap (50) provided at the axial first end of the battery cell may be used as the first electrode terminal, and the end wall (12) of the can (10) provided at the axial second end of the battery cell may be used as the second electrode terminal. However, if both electrode terminals are at the upper portion, it is advantageous for cooling the battery cell toward the bottom of the battery cell (72).

[0149] The first embodiment exemplifies the use of a beading portion and a crimping portion in sealingly securing a cap (50) to a can (10). However, the method of sealingly securing a cap (50) to a can (10) need not be limited thereto. For example, as in the second embodiment described below, the method of sealingly securing a cap (50) to a can (10) may vary.

[0150] Referring to Fig. 17, as a second embodiment, an electrode assembly (20) is inserted into a can (10), the second collector plate (40) and the end wall (12) are welded to form a welded portion (W1), and then an electrolyte can be injected into the interior of the can (10). At this time, a nozzle for injecting the electrolyte can be mounted on the first axial end of the side wall (11). Of course, alternatively, the nozzle can also be mounted on the upper surface of the axial extension portion (33) in the axial direction.

[0151] At least a portion of the electrolyte can be impregnated into the interior of the electrode assembly (20) through a hole provided in the axial extension portion (33) of the first collector plate (30).

[0152] In this way, before covering the opening with a cap (50), an electrolyte can be injected into the interior of the can (10).

[0153] After injecting the electrolyte, the upper surface of the axial extension (33) of the first collector plate (30) can be cleaned if necessary.

[0154] When the injection is completed, the opening of the can (10) is covered with a cap (50) to be sealed as shown in Fig. 18.

[0155] The cap (50) may have a central portion (51) and a peripheral portion (52) that are electrically insulated from each other. The peripheral portion (52) may be formed to surround the central portion (51) on the radially outer side of the central portion (51).

[0156] The central portion (51) and the peripheral portion (52) above can be made of a metal plate. The central portion (51) and the peripheral portion (52) can be made of the same metal or a different metal.

[0157] The boundary between the central portion (51) and the peripheral portion (52) extending in the circumferential direction can be sealed and connected by an insulating sealing portion (53). Accordingly, the connection portion between the central portion (51) and the peripheral portion (52) is sealed, and the central portion (51) and the peripheral portion (52) can be electrically insulated from each other. In some examples, the insulating sealing portion (53) can be a glass seal. In this way, the insulating sealing portion (53) can be implemented by applying various known technologies.

[0158] The surface of the central portion (51) may be arranged to protrude further axially upward than the peripheral portion (52).

[0159] The edge of the peripheral portion (52) of the cap can be joined to the upper portion of the side wall (11). The side wall (11) and the peripheral portion (52) of the cap can be joined to each other so as to be electrically connected.

[0160] As illustrated in Fig. 18, by irradiating a laser (L) along the joint portion of the side wall (11) and the cap (50) extending along the circumferential direction, the side wall (11) and the cap (50) can be deep welded. By the welding portion (W3), the cap (50) and the can (10) are sealed, and the can (10) and the circumferential portion (52) are electrically connected.

[0161] In addition, the first collector plate (30) is bonded to the central portion (51) of the cap (50). The bonding may be thermal bonding. The thermal bonding may be, for example, welding. The welding may be performed by irradiating a laser (L) to the central portion (51) from the outside of the can (10). That is, the welding may be performed by penetrating-welding the central portion (51) of the cap (50) to the upper surface of the axial extension (33) of the first collector plate (30).

[0162] In order to increase the welding reliability of the welded portion (W2), the upper surface of the axial extension portion (33) and the lower surface of the central portion (51) of the cap (50) can be brought into close contact in the axial direction. In addition, the laser (L) can be scanned in the circumferential direction of a trajectory corresponding to the upper surface of the axial extension portion (33).

[0163] The central portion (51) of the cap (50) may have a first polarity, and the peripheral portion (52) and the can (10) may have a second polarity. In one example, the first polarity may be a positive pole and the second polarity may be a negative pole. Of course, the opposite may also be true.

[0164] Accordingly, both the central portion (51) of the first polarity and the peripheral portion (52) of the second polarity can be arranged at the axial first end of the battery cell. In addition, the central portion (51) can be used as the first electrode terminal of the battery cell, and the peripheral portion (52) can be used as the second electrode terminal. Accordingly, both the bus bar connected to the first electrode terminal of the battery cell and the bus bar connected to the second electrode terminal can be positioned at the upper portion of the battery cell. Of course, the cap (50) provided at the axial first end of the battery cell can be used as the first electrode terminal, and the end wall (12) of the can (10) provided at the axial second end of the battery cell can be used as the second electrode terminal. However, if both electrode terminals are at the upper portion, it is advantageous for cooling the battery cell toward the bottom of the battery cell (72).

[0165] The above battery cell (72) can be accommodated in a pack housing (71) of a battery pack (70) as illustrated in FIG. 19. The battery pack (70) may be configured using a battery module, which is an intermediate form of assembly, or the battery pack (70) may be configured directly without a battery module as illustrated.

[0166] Since the battery cell (72) described above has a large volume in itself, there is no particular difficulty in implementing a battery pack (70) even without using an intermediate structure called a battery module. Furthermore, the battery cell (72) has low internal resistance and a higher energy density. Accordingly, the energy density of a battery pack (70) equipped with the battery cell (72) can be implemented even higher.

[0167] A battery pack (70) with such a high energy density can store the same amount of energy while reducing its volume and weight. Therefore, when a battery pack (70) equipped with such battery cells (72) is installed in a vehicle, such as an automobile (80) that uses electricity as its energy source, as illustrated in FIG. 20, the vehicle's mileage per unit of energy can be further increased.

[0168] Even if the above battery cell (72) generates heat in the electrode assembly (20), this heat is quickly dissipated downward through the second electrode (22), the second collector plate (40), and the end wall (12) of the can. Accordingly, if a cooling structure is implemented at the bottom of the battery pack (70), the cooling of the battery cell (72) can be achieved very smoothly.

[0169] Unlike the battery cell illustrated in FIG. 1, the battery cell of the embodiment described above omits the rivet terminal (17), terminal gasket (170), and insulator (19), thereby reducing the number of parts and assembly labor, thereby reducing production costs. In addition, the volume of the electrode assembly can be increased by the amount of volume omitted, thereby increasing the energy density of the battery cell.

[0170] It should be understood that the above-described embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be determined by the claims that follow, rather than by the detailed description set forth above. Furthermore, the meaning and scope of the claims that follow, as well as all possible modifications and variations derived from their equivalent concepts, should be construed as encompassing the scope of the present invention.

[0171] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. A can having a side wall extending axially and surrounding an internal space in a circumferential direction, an opening provided at an axial first end of the side wall, and an end wall connected to an axial second end of the side wall and extending radially to cover the internal space; An electrode assembly having a first electrode and a second electrode and accommodated in the internal space; A first collector plate joined to the axial first end of the electrode assembly so as to be electrically connected to the first electrode; and A cap having an edge sealed and secured to a first end of a side wall of the can; The above first collector plate: An axial extension welded to the cap, the axial upper portion being in contact with the bottom surface of the cap; and A battery cell comprising a radial extension portion extending radially from the axial extension portion and joined to the axial first end of the electrode assembly.

2. A battery cell according to claim 1, comprising a center tube shape having a center hole extending in the axial direction.

3. In claim 1, the axial extension portion has a hole extending axially, The above hole is a battery cell that communicates with the core cavity of the electrode assembly.

4. A battery cell according to claim 1, wherein the radial extension is connected to the axial lower end of the axial extension.

5. In claim 1, the radial extension is a battery cell joined to a tab of the first electrode provided at the axial first end of the electrode assembly.

6. A battery cell according to claim 1, wherein the axial extension is joined to the cap by a first welded portion that is penetrated and welded from the outer surface of the cap.

7. In claim 1, the side wall: A beading portion provided by recessing the side wall radially inward between the first end of the side wall and the first end of the electrode assembly in the axial direction; and It includes a crimping portion formed so that the first end of the side wall extends radially inward; A battery cell, wherein the edge of the cap is positioned axially between the beading portion and the crimping portion, and the edge is compressed axially by the beading portion and the crimping portion while interposing a gasket.

8. A battery cell according to claim 1, wherein the edge of the cap is seam-welded to the side wall.

9. In claim 8, the cap has a central portion and a peripheral portion that are electrically insulated from each other, The above axial extension is welded to the lower surface of the central portion, the battery cell.

10. A battery cell according to claim 1, further comprising an insulating tape attached to the upper surface of the edge of the radial extension and the outer peripheral surface of the axial first end of the peripheral surface of the electrode assembly.

11. A battery cell according to claim 1, wherein the second electrode is electrically connected to the end wall.

12. A battery cell according to claim 11, wherein the second electrode is electrically connected to the end wall by a second weld formed by penetrating welding from the outer surface of the end wall.

13. In claim 11, a second collector plate is further included, which is joined to the axial second end of the electrode assembly so as to be electrically connected to the second electrode; The axial inner surface of the second collector plate is joined to the tab of the second electrode provided at the axial second end of the electrode assembly, A battery cell in which the axial outer surface of the second collector plate is in contact with the end wall and is welded by the second welding portion.

14. A battery pack comprising a battery cell according to any one of claims 1 to 13 and a pack case containing the battery cell.

15. A battery pack according to claim 14, wherein the battery cell is built into the pack case such that the end wall is in contact with the bottom of the pack case and the cap faces upward.

16. A battery pack according to claim 14, wherein a cooling structure for cooling the battery cell through the end wall of the battery cell is provided on the bottom of the pack case.

17. A vehicle equipped with the battery pack of claim 14 and driven by power from the battery pack.