Battery cell, and battery pack and vehicle including same

Abstract

A battery cell according to the present invention includes: an electrode assembly in which a first electrode, a second electrode, and a separator between the first electrode and the second electrode are wound around a winding axis; a housing accommodating the electrode assembly through an opening formed on one side and having a bent portion formed by bending an end of the opening inward; a current collecting plate coupled to one surface of the electrode assembly and electrically connected to the first electrode of the electrode assembly; and a cap coupled to the bent portion to cover the opening of the housing, wherein a portion of the current collecting plate may be coupled to the bent portion of the housing.

Description

Battery cells, battery packs containing the same, and vehicles

[0001] The present invention relates to a battery cell, a battery pack including the same, and a vehicle. This application claims priority to Korean Patent Application No. 10-2024-0099600, filed July 26, 2024, the entire disclosure of which, in its specification and drawings, is incorporated herein by reference.

[0002] Cylindrical battery cells house jelly-roll-shaped electrode assemblies within a cylindrical metal can. They are more shock- and temperature-resistant than pouch-type batteries. Consequently, demand for metal can-shaped cells in vehicle battery packs is growing.

[0003] The process of manufacturing a battery cell using a cylindrical can includes deep drawing a metal sheet to form a circular bottom portion and a circular tubular side wall portion connected thereto, accommodating an electrode assembly therein, and then covering the open end of the side wall portion with a lead to finish the process.

[0004] The open end of the battery can is covered with a lead, and the lead and battery can are secured by crimping or seam welding.

[0005] In batteries, increasing capacity and reducing costs are critical technological challenges, and seam welding is attracting attention. Preventing damage to the electrode assembly housed within the housing during seam welding can be a critical technical challenge.

[0006] Referring to FIG. 1, an example of a deep welding method, i.e., a method of finishing the opening of a housing of a cylindrical battery (1000) by directly welding the housing (1100) and the cap (1200) without using a beading and crimping process, is shown.

[0007] In the case of applying such a deep welding process, there is a risk that penetration of the parts may occur during the welding process for joining the housing (1100) and the cap (1200) when laser welding is applied, or that the separator may be damaged as heat is transferred to the electrode assembly inside the housing (1100).

[0008] In addition, as illustrated in FIG. 1, the portion where the housing (1100) and the cap (1200) come into contact and the portion where the housing (1100) and the collector plate (1300) come into contact may be spaced apart from each other. Therefore, welding between the housing (1100) and the cap (1200) and welding between the housing (1100) and the collector plate (1300) need to be performed separately, which inevitably leads to complexity in the process.

[0009] Therefore, there is a need for the development of a battery cell structure that can suppress the risk of damage to the electrode assembly during welding, increase the convenience of welding, and / or prevent loss of energy density of the battery.

[0010] The present invention was created in consideration of the above-described problems, and aims to provide a battery cell that enables reduction of the risk of damage to an electrode assembly during welding, increase of convenience in welding, and / or prevention of loss of energy density of a battery.

[0011] 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.

[0012] According to one embodiment of the present invention for solving the above-described problem, a battery cell comprises: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis; a housing that receives the electrode assembly through an opening formed on one side and has a bent portion formed by bending an end on the side of the opening inward; a current collector plate that is coupled to one surface of the electrode assembly and is electrically connected to the first electrode of the electrode assembly; and a cap that is coupled to the bent portion and covers the open portion of the housing; wherein a portion of the current collector plate can be coupled to the bent portion of the housing.

[0013] According to the present invention, the current collector plate has a first coupling portion coupled to the electrode assembly and a second coupling portion coupled to the bend portion, wherein the second coupling portion can be welded to the bend portion in a state of being overlapped at least twice by bending.

[0014] In addition, it is characterized in that welding is performed while a part of the above-mentioned collector plate is interposed between the cap and the above-mentioned bending portion.

[0015] In addition, the inner end of the above-mentioned bending portion is formed in a stepped manner, and a part of the above-mentioned collector plate is inserted into the stepped portion and placed between the above-mentioned bending portion and the cap.

[0016] In addition, the edge of the cap is provided with a groove formed concavely upward, and a part of the collector plate is inserted into the groove and placed between the folded portion and the cap.

[0017] In addition, the collector plate is characterized in that it has a protrusion that protrudes upward in a state of being overlapped in two layers by bending, and that welding is performed in a state in which the protrusion is interposed between the cap and the bending portion.

[0018] In addition, the welding is characterized in that the edge portion of the collector plate is in contact with the lower surface of the bending portion, and the edge of the cap is in contact with the upper surface of the bending portion.

[0019] In addition, it is characterized in that welding is performed while the edge of the cap is interposed between the bending portion and the collector plate.

[0020] According to another aspect of the present invention, a battery cell may include an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis; a housing that receives the electrode assembly through an opening formed on one side thereof and has a bent portion formed by bending an end on the side of the open portion inwardly; and a cap that is coupled to the bent portion to cover the open portion of the housing and is electrically connected to the first electrode of the electrode assembly.

[0021] According to the present invention, the cap is characterized in that it is provided with an injection port for injecting an electrolyte into the interior of the housing.

[0022] In addition, the edge of the cap is coupled to the bending portion, and at least a portion of the central portion of the cap protrudes toward the electrode assembly and is coupled to the electrode assembly.

[0023] In addition, the cap is characterized in that it is located in the inner region of the bending portion and has a breaking portion for venting.

[0024] A battery pack according to one embodiment of the present invention may include a battery cell according to one embodiment of the present invention.

[0025] A vehicle according to one embodiment of the present invention for solving the above-described problem may include a battery pack according to one embodiment of the present invention.

[0026] According to the present invention, damage to the separator of an electrode assembly caused by the laser used during welding or the heat generated during welding can be prevented or suppressed. Furthermore, the convenience of the welding process can be improved, and furthermore, the welding between the housing, cap, and current collector can be performed more firmly.

[0027] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0029] Figure 1 is a drawing showing a method of fixing a lead and a battery can using a conventional crimping method.

[0030] Figure 2 is a perspective view of a battery cell according to one embodiment of the present invention.

[0031] Figure 3 is a perspective view of the battery cell shown in Figure 2 in an upside-down state.

[0032] Figure 4 is a schematic perspective view of the housing illustrated in Figure 2.

[0033] Figure 5 is a schematic cross-sectional view taken along the AA' direction of Figure 2.

[0034] Figure 6 is a schematic perspective view of the collector plate illustrated in Figure 5.

[0035] FIG. 7 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to one embodiment of the present invention.

[0036] FIG. 8 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0037] FIG. 9 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0038] FIG. 10 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0039] FIG. 11 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0040] FIG. 12 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0041] FIG. 13 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0042] FIG. 14 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0043] FIG. 15 is a drawing for explaining a process for manufacturing a housing according to one embodiment of the present invention.

[0044] FIG. 16 is a schematic cross-sectional view of a battery cell according to another embodiment of the present invention.

[0045] FIG. 17 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0046] FIG. 18 is a drawing for explaining a vehicle including the battery pack of FIG. 17.

[0047] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0048] The present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and with various modifications. However, these embodiments are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. Therefore, the present invention is not limited to the embodiments disclosed below, but should be understood to include all modifications, equivalents, and substitutes included within the technical spirit and scope of the present invention, as well as substitutions or additions of the components of one embodiment with those of another embodiment.

[0049] Furthermore, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar components will be omitted, and the differences will be described.

[0050] The attached drawings are merely intended to facilitate understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification, but should be understood to encompass all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention. In the drawings, the components may be expressed in exaggerated sizes or thicknesses for ease of understanding, but the scope of protection of the present invention should not be construed as being limited thereby.

[0051] The terminology used in this specification is only used to describe specific implementations or examples and is not intended to limit the present invention. In addition, the singular expression includes the plural expression unless the context clearly indicates otherwise. In the specification, terms such as "comprises" and "consists of" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification. In other words, it should be understood that terms such as "comprises" and "consists of" in the specification do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0052] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0053] Meanwhile, in this specification, terms indicating directions such as up, down, left, right, front, and back may be used, but these terms are only for convenience of explanation, and it is obvious to those skilled in the art that these terms may vary depending on the position, arrangement, rotation, and position of the object being targeted, or the position of the observer.

[0054] In describing the embodiment, the winding axis 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 approaching (centripetal) or moving away (centrifugal) from the axis, and the circumferential direction refers to the direction surrounding the axis.

[0055]

[0056] Fig. 2 is a perspective view of a battery cell according to one embodiment of the present invention. Fig. 3 is a perspective view of the battery cell illustrated in Fig. 2, upside down. Fig. 4 is a schematic perspective view of the housing illustrated in Fig. 2. Fig. 5 is a schematic cross-sectional view taken along line AA' of Fig. 2.

[0057] Referring to FIGS. 2 to 5, a battery cell (10) according to the present embodiment may include an electrode assembly (100), a housing (200), a collector plate (300), and a cap (400).

[0058]

[0059] The electrode assembly (100) may be in the form of a jelly-roll in which a first electrode, a second electrode, and a separator interposed therebetween are wound in the direction of a winding axis. Specifically, the electrode assembly (100) may be manufactured as a cylindrical jelly-roll by preparing a first electrode, a second electrode, and a separator that extend in the longitudinal direction with a predetermined width, forming a laminate by stacking the first electrode, the separator, the second electrode, and the separator in that order, and then winding the laminate around a winding axis. The structure of the electrode assembly (100) is not limited by the embodiment, and may have a winding structure well known in the art.

[0060]

[0061] The housing (200) may be formed in a hollow shape. An opening may be formed at one end of the housing (200). In other words, one end of the housing (200), for example, an end in an upward direction (Z-axis direction) with reference to FIG. 4, is formed in an open structure. In addition, the other end of the housing (200), for example, a lower end, may be formed in a closed structure. The electrode assembly (100) may be accommodated inside the housing through the opening of the housing (200).

[0062] In particular, a bending portion (230) may be provided at the end of the side where the opening is formed in the housing (200), i.e., the upper end. The bending portion (230) may be formed in a form in which a portion of the upper end is bent inward.

[0063] To be more specific, as illustrated in FIG. 5, the housing (200) may include a bottom portion (210) and a side wall portion (220) that extends upward from an edge of the bottom portion (210). In addition, a portion of the upper end of the side wall portion (220) may be bent inward, and the bent portion may form a folded portion (230). At this time, the folded portion (230) may be bent to a degree that forms a substantially right angle with the side wall portion (220). For reference, the side wall portion (220) and the folded portion (230) may be bent to be nearly right angles, and in order to express this more intuitively, the expression “folding” may be used interchangeably with “bending.” The bending of the folded portion (230) may be performed by rolling processing (or roll flanging processing), which will be described later.

[0064]

[0065] The current collector plate (300) may be coupled to one surface of the electrode assembly (100). The current collector plate (300) may be electrically connected to the first electrode. Specifically, the current collector plate (300) may be made of a metal material and may be formed in a roughly plate shape. The current collector plate (300) may be coupled to one surface of the electrode assembly (100), for example, to the upper surface (+Z-axis direction) of the electrode assembly (100) with reference to FIG. 5. At this time, a portion of the current collector plate (300) may be coupled to the electrode assembly (100) by welding. And, by this coupling, the current collector plate (300) may be electrically connected to the first electrode of the electrode assembly (100).

[0066] Additionally, a portion of the collector plate (300) may be coupled to the housing. In particular, a portion of the collector plate (300) may be coupled to the bending portion (230). The collector plate (300) may electrically connect the housing (200) and the first electrode.

[0067]

[0068] The cap (400) can be coupled to the housing (200) to cover the opening of the housing (200). Specifically, the cap (400) can be formed in a shape corresponding to the upper end of the housing. For example, the cap (400) can be formed in a circular plate shape. The cap (400) can be coupled to the housing (200). For example, the cap (400) can be welded to the housing (200), thereby covering, i.e., closing, the opening of the housing (200). In particular, in the present embodiment, the edge of the cap (400) can be welded to the bent portion (230) of the housing.

[0069]

[0070] According to the embodiment of the above configuration, the cap (400) and the collector plate (300) can be welded to the folded portion (230). At this time, since the folded portion (230) is folded with respect to the side wall portion (220), the cap (400) and the collector plate (300) can be easily and firmly welded.

[0071] Specifically, in the conventional case, a cap and a collector plate were welded to the side wall of a vertically erected housing. However, the cap and collector plate have an overall plate shape and can be arranged horizontally. In other words, the cap and collector plate, which are arranged horizontally, must be welded to the surface of the vertically arranged housing. Therefore, the welding difficulty is high, and the welding area may be limited. Furthermore, during the laser welding process, there is a risk of damage to the separator as the laser penetrates the area where the housing and the cap are in contact, or the heat generated during welding is transferred to the electrode assembly inside the housing.

[0072] However, in the present embodiment, the cap (400) and the collector plate (300) can be welded to the horizontally bent portion (230). That is, when viewed as a whole, welding can be performed in a state where the cap (400), the collector plate (300), and the bend portion (230) are all horizontally arranged, which can be completely different from the configuration used in conventional welding. Accordingly, the welding process can be facilitated, and the welding contact area can be increased. In addition, penetration by the laser during the welding process and heat transfer to the electrode assembly can be prevented or suppressed.

[0073]

[0074] Below, the structure of the collector plate and cap will be further explained.

[0075] Figure 6 is a schematic perspective view of the collector plate illustrated in Figure 5.

[0076] Referring to FIGS. 6 and 5 together, the current collector plate (300) according to the present embodiment may include a first coupling portion (320) and a second coupling portion (330). The first coupling portion (320) may be welded to the electrode assembly (100) and electrically connected to the first electrode. The first coupling portion (320) may be provided in multiple numbers, and for example, four first coupling portions (320) may be provided as illustrated in FIG. 6. The multiple first coupling portions (320) may be arranged radially based on the center (310). The second coupling portion (330) may be coupled to the bending portion (230) and electrically connected to the housing (200). The second coupling portion (330) may have a predetermined width and may be formed to be long in one direction. The second coupling portion (330) may be provided in multiple numbers, for example, four second coupling portions (330) may be provided. The multiple second coupling portions (330) may be arranged radially with respect to the center (310). In this case, the first coupling portion (320) and the second coupling portion (330) may be arranged alternately.

[0077] In addition, the current collector plate (300) may be formed in a plate shape overall. A through hole for injecting an electrolyte may be formed in the center (310) of the current collector plate.

[0078] In particular, in the present embodiment, the end portion of the second coupling portion (330) may be overlapped at least twice by bending. Specifically, the end portion of the second coupling portion (330) is bent inwardly by 180 degrees, so that the second coupling portion (330) may be overlapped twice. At this time, the bent portion (i.e., the overlapping portion) may be bent so as to be positioned on the upper side. In addition, the twice-overlapping portion may be coupled to the bend portion (230) of the housing. This will be described later. Meanwhile, in the present embodiment, the second coupling portion is overlapped twice, but it may be configured to overlap more than that.

[0079]

[0080] Again, referring to FIGS. 2 and 5, the cap (400) may be formed in an overall plate shape. A hole may be formed in the center of the cap (400) for injecting electrolyte into the housing (200). Furthermore, a sealing plug (450) may be coupled to this hole. After the injection of the electrolyte is complete, the sealing plug (450) may be coupled to the hole to seal the hole.

[0081]

[0082] The basic structure of the current collector plate (300) and the cap (400) may be as described above. However, the detailed structures of the end portion of the second connecting portion (330) and the edge portion of the cap (400) in the current collector plate (300) may be changed in various forms. In other words, the detailed structures of the end portion of the second connecting portion (330) and the edge portion of the cap (400) may be changed in accordance with the structure in which the current collector plate (300), the cap (400), and the bending portion (230) are welded. This will be described in detail in the process of explaining embodiments of the welding structure.

[0083]

[0084] Below, examples of structures in which a collector plate (300) and a cap (400) are welded to a bending portion (230) will be described.

[0085] Figures 7 to 14 are partially enlarged cross-sectional views illustrating an embodiment of a structure in which a collector plate, a cap, and a housing are welded. Specifically, Figures 7 to 14 are enlarged cross-sectional views of a bent portion of the housing and a portion of the collector plate and cap joined to the bent portion.

[0086]

[0087] FIG. 7 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to one embodiment of the present invention.

[0088] Referring to FIGS. 7 and 6 together, a portion of the current collector plate (300) may be bent and overlapped in at least two layers. Specifically, an end portion (331) of a second coupling portion (330) of the current collector plate may be bent and overlapped in two or more layers. For example, as illustrated in FIG. 7, an end portion (331) of the second coupling portion may be folded (i.e., bent) 180 degrees inward, so that the second coupling portion (330) may be overlapped in two layers. At this time, the bending may be performed such that the folded portion (331) is disposed on the upper side. For reference, although not illustrated in FIG. 7, referring to FIG. 6, an electrode assembly (100) may be coupled to a lower surface of the current collector plate (300). In other words, the current collector plate (300) may be coupled to an upper surface of the electrode assembly (100).

[0089] And, the above-mentioned double-layered portion can be joined to the folded portion (230). Specifically, the folded portion (331) of the second joining portion (330) can be joined to the lower surface of the folded portion (230). And, the edge (410) of the cap (400) can be joined to the upper surface of the folded portion (230). At this time, as illustrated in FIG. 7, the edge (410) of the cap can be formed to have a thinner thickness than the central portion.

[0090] That is, the cap (400), the bending portion (230), and the second connecting portion (331) can be sequentially stacked in the vertical direction. In addition, such an arrangement may be possible because the bending portion (230) is bent and arranged horizontally.

[0091] The above-described laminated cap (400), folded portion (230), and second joint portion (330) can be welded. For example, the points indicated by arrows (inverted triangle shapes) in FIG. 7 can be welded vertically. Then, the cap (400), folded portion (230), and second joint portion (330) can be welded simultaneously. In other words, the welded portion (welding area) can extend vertically to form the cap, folded portion, and current collector plate.

[0092] According to the present embodiment, the cap (400), the housing (200) (i.e., the bent portion), and the collector plate (300) can be welded while being stacked in the vertical direction. At this time, the cap (400), the housing (200) (i.e., the bent portion), and the collector plate (300) can be in surface contact with each other. Therefore, the welding process can be facilitated. In addition, the risk of the portion to be welded being penetrated by the laser during the welding process can also be reduced.

[0093] In addition, in the conventional case, welding was performed on the side of the housing (the side of the top of the housing), and thus, the welding heat was directly transmitted to the electrode assembly through the side of the housing, causing a problem of damage to the separator. However, in the case of the present embodiment, welding is performed on the bent portion (230) rather than the side wall portion (220) of the housing, and thus, damage to the separator due to the welding heat can be prevented or suppressed.

[0094] In particular, in the case of the present embodiment, welding can be performed in a state where the second joint portion (330) is overlapped in two layers. At this time, welding can mainly occur between the folded portion (331) and the bent portion (230) of the second joint portion, and the second joint portion below the folded portion (331) can be unwelded or partially welded. In this respect, the effect of the welding heat being blocked from being transferred to the electrode assembly (100) by the current collector plate (300) (specifically, the current collector plate below the folded portion) can be exhibited. Therefore, damage to the separator due to the welding heat can be further prevented.

[0095] In addition, when welding two components, the close contact of the components to be welded with each other can be an important factor in determining the welding quality. In the present embodiment, the end of the second joint (330) is overlapped in two layers, and at this time, since the second joint (330) is made of a metal material, it can have a certain level of elasticity. Therefore, the folded portion (331) of the second joint can have a restoring force to unfold again, and thus the folded portion (331) can be closely contacted with the folded portion (230). Accordingly, the welding quality between the folded portion (230) and the collector plate (330) can be improved.

[0096] Meanwhile, referring to Fig. 7, the point (R) where the side wall portion and the bend portion of the housing are connected may be formed into a curved surface. This is because, due to the characteristics of the roll flanging processing method described below, the side wall portion and the bend portion may be bent into such a curved shape. However, the radius of curvature of this curved surface may be very small, and thus, the expressions "side wall portion and bend portion are bent" may be used interchangeably.

[0097]

[0098] FIG. 8 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0099] Referring to Fig. 8, the end (331) of the second connecting portion of the current collector (300) can be bent and overlapped in two layers. The double-overlapping portion (3331) can be coupled to the lower surface of the bending portion (230). In addition, the edge (410) of the cap can be coupled to the upper surface of the bending portion (230). At this time, as illustrated in Fig. 8, the edge (410) of the cap can be positioned higher than the central portion. In addition, a bent section, i.e., a connecting portion (411), can be provided between the central portion and the edge (410) of the cap (400).

[0100] According to the present embodiment, the cap (400), the bend portion (230), and the second joint portion (330) can be welded while being stacked in a vertical direction. At this time, the cap (400), the bend portion (230), and the second joint portion (330) can be in surface contact with each other. Therefore, the welding process can be facilitated. In addition, the risk of the portion being welded being penetrated by the laser during the welding process can also be reduced.

[0101]

[0102] FIG. 9 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0103] Referring to Fig. 9, a portion of the current collector (300) may be interposed between the cap (400) and the folded portion (230), and welding may be performed in this state. Specifically, the end portion (331) of the second connecting portion may have a first part (331a) that is bent upwards, and a second part (331b) that extends horizontally from the first part (331a). In addition, the second part (331b) of the second connecting portion may be interposed between the folded portion (230) and the cap (400).

[0104] For example, as illustrated in FIG. 9, the inner end of the bend portion (230) may be formed in a stepped manner. Then, the second part (331b) may be mounted on the stepped surface (231). Then, the edge (410) of the cap may be mounted on the upper side of the bend portion (230) and the second part (331b).

[0105] According to the present embodiment, the cap (400), the bending portion (230), and the second part (331b) of the current collector plate are stacked in the vertical direction and can be welded in this state. Therefore, the cap (400), the bending portion (230), and the current collector plate (330) can be welded at once. At this time, the cap (400), the bending portion (230), and the second joining portion (330) can be in surface contact with each other. Therefore, the welding process can be facilitated. In addition, the risk of the part to be welded being penetrated by the laser during the welding process can also be reduced.

[0106] Additionally, as shown by the arrow in Fig. 9, the portion where the cap (400) and the folded portion (230) are laminated can be additionally welded, thereby more firmly connecting the cap (400) to the housing (200).

[0107]

[0108] FIG. 10 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0109] Referring to Fig. 10, a portion of the current collector (300) may be interposed between the cap (400) and the folded portion (230), and welding may be performed in this state. Specifically, the end portion (331) of the second connecting portion may have a first part (331a) that is bent upwards, and a second part (331b) that extends horizontally from the first part (331a). In addition, the second part (331b) of the second connecting portion may be interposed between the folded portion (230) and the cap (400).

[0110] For example, as illustrated in FIG. 10, the edge (410) of the cap may be seated on the upper surface of the folded portion (230). In addition, a groove (410a) that is concavely formed upward may be provided on the edge (410) of the cap. The second part (331b) of the second connecting portion may be inserted into the groove (410a).

[0111] According to the present embodiment, the cap (400), the bending portion (230), and the second part (331b) of the current collector plate are stacked in the vertical direction and can be welded in this state. Therefore, the cap (400), the bending portion (230), and the current collector plate (330) can be welded at once. At this time, the cap (400), the bending portion (230), and the second joining portion (330) can be in surface contact with each other. Therefore, the welding process can be facilitated. In addition, the risk of the part to be welded being penetrated by the laser during the welding process can also be reduced.

[0112] Additionally, as shown by the arrow in Fig. 10, the portion where the cap (400) and the folded portion (230) are laminated can be additionally welded, thereby more firmly connecting the cap (400) to the housing (200).

[0113]

[0114] FIG. 11 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0115] Referring to Fig. 11, the current collector plate (300) may be provided with a protrusion (332). The protrusion (332) may be formed by overlapping a portion of the current collector plate (300). For example, the protrusion (332) may be formed by bending and overlapping a portion of the second coupling portion (330). Specifically, the second coupling portion (330) is first bent upwards by 90 degrees, then bent downwards by 180 degrees for a second time so that a certain portion overlaps, and then bent by 90 degrees for a third time so that the end (331) of the second coupling portion is horizontal, thereby forming the protrusion (332) of the above structure. The protrusion (332) may be formed to protrude upwards.

[0116] The edge (410) of the cap (400) may be positioned on the upper side of the folded portion (230). At this time, the cap (400) may be formed in a stepwise manner, so that the thickness of the edge (410) of the cap may be formed thinner than the thickness of the central portion (412). Then, a gap may be formed between the folded portion (230) and the central portion (412) of the cap, and the protrusion (332) may be inserted into this gap.

[0117] According to the present embodiment, the protrusion (332) is inserted between the cap (400) and the folded portion (230), and welding can be performed in this state. Then, the cap (400), the folded portion (230), and the collector plate (300) can be welded at once. In addition, although not shown in the drawing, the portion where the edge (410) of the cap and the folded portion (230) are laminated can be additionally welded, thereby more firmly connecting the cap (400) to the housing (200).

[0118] In particular, in the present embodiment, the double-layered protrusion (332) may have a predetermined elasticity, and thus the protrusion (332) may be opened in the space between the folded portion (230) and the cap (400). Accordingly, the protrusion (332) may be tightly fitted to the folded portion (230) and the cap (400) to be completely adhered, and thus the cap (400), the folded portion (230), and the collector plate (300) may be firmly welded.

[0119]

[0120] FIG. 12 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0121] Referring to Fig. 12, the collector plate (300) may be provided with a protrusion (332). The protrusion (332) may be formed to protrude upward.

[0122] The edge (410) of the cap (400) may be positioned on the upper side of the folded portion (230). At this time, the cap (400) may be formed in a stepwise manner so that the thickness of the edge (410) of the cap may be formed thinner than the thickness of the central portion (412). Then, a gap may be formed between the folded portion (230) and the central portion (412) of the cap, and the protrusion (332) may be inserted into this gap. In addition, in a state where the protrusion (332) is inserted, the edge (331) of the collector plate may be in close contact with the folded portion (230), and the central portion of the collector plate may be in close contact with the lower surface of the cap (400).

[0123] According to the present embodiment, the protrusion (332) is inserted between the cap (400) and the folded portion (230), and welding can be performed in this state. Then, the cap (400), the folded portion (230), and the collector plate (300) can be welded at once. In addition, as shown by the arrows in FIG. 12, the portion where the cap (400), the folded portion (230), and the collector plate (300) are laminated can be additionally welded at once, and through this, the cap (400), the folded portion (230), and the collector plate (300) can be welded more firmly.

[0124]

[0125] FIG. 13 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0126] Referring to Fig. 13, the collector plate (300) may be provided with a protrusion (332). The protrusion (332) may be formed to protrude upward.

[0127] The cap (400) may be positioned on the inner side of the folded portion (230). Specifically, the edge of the cap may be in contact with the inner surface of the folded portion (230). At this time, the cap (400) may be formed in a stepped manner, so that the thickness of the edge of the cap may be formed thinner than the thickness of the central portion (412). Then, a gap may be formed between the folded portion (230) and the central portion (412) of the cap, and the protrusion (332) may be inserted into this gap.

[0128] According to the present embodiment, the protrusion (332) is inserted between the cap (400) and the bend portion (230), and welding can be performed in this state. In particular, the protrusion (332) can be brought into close contact with the cap (400) and the bend portion (230) due to the elasticity of the protrusion (332). Then, the cap (400), the bend portion (230), and the collector plate (300) can be easily and firmly welded at once.

[0129] In particular, according to the present embodiment, the upper surface of the bending portion (230) and the upper surface of the cap (400) can form the same plane. In other words, the upper surface of the battery cell (10) can form an entire plane. When the upper surface of the battery cell is formed as a plane in this way, the battery cell can be stably placed when placed in the pack housing. For reference, when placing the battery cell, the battery cell can be placed upside down so that the upper surface of the battery cell touches the bottom of the pack housing. In addition, when cooling is performed through the upper surface of the battery cell (10), the cooling area (i.e., contact area) increases, enabling efficient cooling.

[0130] Meanwhile, in the above drawing, the edge of the collector plate, i.e., the end (331) of the second connecting portion, is depicted as being separated from the folded portion (230). However, as in FIG. 12, the end (331) of the second connecting portion may be in close contact with the lower surface of the folded portion (230). In this case, the portion where the folded portion (230) and the collector plate (300) are laminated may be additionally welded, thereby enabling the folded portion (230) and the collector plate (300) to be welded more firmly.

[0131]

[0132] FIG. 14 is a partially enlarged cross-sectional view illustrating a structure in which a current collector, a cap, and a housing are welded in a battery cell according to another embodiment of the present invention.

[0133] Referring to Fig. 14, the edge (410) of the cap (400) may be interposed between the folded portion (230) and the second connecting portion (330). Specifically, the cap (400) is formed in a step manner, and thus the edge (410) of the cap may be formed thinner than the center portion. The cap (400) may be placed on the upper side of the current collector plate (300). At this time, the edge (410) of the cap is placed on the lower side of the folded portion (230), and thus the edge (410) of the cap may be in contact with the lower surface of the folded portion (230).

[0134] According to the present embodiment, the bending portion (230), the cap (400), and the collector plate (300) are stacked in a vertical direction and can be welded in this state. At this time, the bending portion (230), the cap (400), and the collector plate (300) can be in surface contact with each other. Therefore, the welding process can be facilitated. In addition, the risk of the part to be welded being penetrated by the laser during the welding process can also be reduced.

[0135]

[0136] Again, referring to FIG. 5, the battery cell (10) according to the present embodiment may further include an electrode terminal (500) and a second collector plate (600).

[0137] The electrode terminal (500) can be coupled to a closed end of the housing (200), i.e., the bottom portion (210) of the housing. Specifically, a terminal hole can be formed through the bottom portion (210) of the housing, and the electrode terminal (500) can be coupled to this terminal hole.

[0138] The second collector plate (600) can be joined, more specifically, welded, to the lower surface of the electrode assembly (100). The second collector plate (600) can be electrically connected to the second electrode of the electrode assembly (100). The second collector plate (600) can be welded to the electrode terminal (500), so that the electrode terminal (500) can be electrically connected to the second electrode.

[0139] Additionally, an insulating member (G1) for insulation between the housing (200) and the electrode terminal (500), and an insulating sheet (G2) for insulation between the second collector plate (600) and the housing (200) may be further provided.

[0140]

[0141] Hereinafter, a method of forming a bend by bending a housing, such as a roll flanging process, will be described. FIG. 15 is a drawing illustrating a process for manufacturing a housing according to an embodiment of the present invention.

[0142] Referring to Fig. 15, the housing (200) can be fixed by a clamping member (P2). At this time, an electrode assembly may be inserted into the interior of the housing (200).

[0143] A roller (P1) may be arranged on the upper side of the housing (200). For example, two rollers (P1) may be arranged on the upper side of the housing. The two rollers (P1) may be arranged so that their processing surfaces correspond to the edges of the housing (200). Each roller (P1) may rotate around a first rotational axis (X1). In addition, the two rollers (P1) may revolve around a second rotational axis (X2). When the roller (P1) rotates and revolves, and the processing surface of the roller, i.e., the rounded surface, is pressed downward while in contact with the end of the housing (200), the end of the housing (200) may be bent (folded) inwardly along the processing surface, i.e., the curved surface, of the roller (P1). At this time, by adjusting the processing time and the processing interval so that the housing (200) can be sufficiently plastically deformed, the bending part can be processed into a smooth surface.

[0144]

[0145] FIG. 16 is a schematic cross-sectional view of a battery cell according to another embodiment of the present invention.

[0146] Referring to FIG. 16, a battery cell (10A) according to the present embodiment may include an electrode assembly (100), a housing (200), and a cap (400A).

[0147] Here, the electrode assembly (100) and housing (200) may be substantially the same as the embodiment illustrated in FIG. 5 described above.

[0148] The cap (400A) can be coupled to the housing (200) and cover the opening of the housing (200). Specifically, the cap (400A) can be formed in a shape corresponding to the opening of the housing (200). The cap (400A) is coupled to the housing (200) and can cover, i.e., close, the opening of the housing.

[0149] Specifically, the edge (410) of the cap can be welded to the folded portion (230). For example, the edge (410) of the cap is in contact with the upper surface of the folded portion (230), and in this state, the edge (410) of the cap and the folded portion (230) can be welded.

[0150] And, at least a part of the central portion (420) of the cap (400A) may protrude toward the electrode assembly (100). For example, as illustrated in FIG. 16, the central portion (420) of the cap may protrude downward compared to the edge (410), and particularly, in the present embodiment, the entire central portion (420) may protrude downward. The central portion (420) of the cap may be in contact with the upper surface of the electrode assembly (100). The central portion (420) of the cap may be welded to the electrode assembly (100), and thus, the cap (400A) and the first electrode of the electrode assembly (100) may be electrically connected.

[0151] That is, when comparing the present embodiment with the embodiment illustrated in FIG. 5, the current collector plate (300) that connected the first electrode of the electrode assembly (100) and the housing (200) in the embodiment of FIG. 5 may not be provided in the present embodiment. In addition, the cap (400A) is electrically connected to the first electrode by being welded to the electrode assembly (100), and the first electrode and the housing (200) can be electrically connected through the cap (400A). In other words, the cap (400A) according to the present embodiment can replace the current collector plate.

[0152] In addition, the battery cell (10A) according to the present embodiment may further include an electrode terminal (500), a second collector plate (600), an insulating member (G1), and an insulating sheet (G2), and these configurations may be substantially the same as in the embodiment of FIG. 5.

[0153]

[0154] According to the present embodiment, a liquid injection port may be formed through the center of the cap (400A). The liquid injection port may be a passage for injecting electrolyte into the interior of the housing (200). A sealing plug (450) may be coupled to this liquid injection port. After the injection of the electrolyte is completed, the liquid injection port may be sealed by the sealing plug (450).

[0155]

[0156] Additionally, although not shown in the drawing, the cap (400A) may be provided with a break portion. The break portion may be designed to rapidly discharge gases generated during thermal runaway of the battery cell. The break portion may be formed by forming a notch, groove, or the like in the cap (400A) to reduce the strength of the corresponding portion. The break portion may be located in the inner region of the bending portion and may be formed, for example, in a concentric shape.

[0157]

[0158] Fig. 17 is a drawing for explaining a battery pack according to one embodiment of the present invention. Fig. 18 is a drawing for explaining a vehicle including the battery pack of Fig. 17.

[0159] Referring to FIG. 17, a battery pack (1) according to the present invention may include at least one battery cell (10) according to the present invention described above. In addition, the battery pack (1) according to the present invention may include a pack housing (1a) capable of accommodating the at least one battery cell (1). The battery pack (1) may be configured using a battery module, which is an intermediate form of assembly, or may be configured directly without a battery module, as illustrated. Since the battery cell (1) itself has a large volume, there may be no particular difficulty in implementing the battery pack (1) even without using an intermediate structure called a battery module.

[0160] In addition, the battery pack (1) may further include various other components in addition to the battery cells (10), such as components of the battery pack (1) known at the time of application of the present invention, such as a BMS, a relay, a current sensor, etc.

[0161]

[0162] Referring to FIG. 18, a vehicle (V) according to the present invention may include at least one battery pack (1) according to the present invention.

[0163] The battery pack (1) according to the present invention can be applied to automobiles such as electric vehicles or hybrid vehicles. That is, the automobile (V) according to the present invention can include a battery cell (10) according to the present invention or a battery pack (1) according to the present invention.

[0164]

[0165] The above battery pack and vehicle, which are equipped with a battery cell according to the present invention, can have the same advantages as the battery cell.

[0166]

[0167] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0168]

[0169] [Explanation of symbols]

[0170] V: Car

[0171] 1: Battery pack

[0172] 10: Battery cell

[0173] 100: Electrode assembly

[0174] 200: Housing

[0175] 210: Bottom

[0176] 220: Side wall

[0177] 230: Bend section

[0178] 300: Current collector plate

[0179] 320: First joint

[0180] 330: Second joint

[0181] 400: Cap

[0182] 500: Electrode terminal

[0183] 600: Second Collection Edition

[0184] G1: Insulating material

[0185] G2: Insulating sheet

Claims

1. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis; A housing that accommodates the electrode assembly through an opening formed on one side and has a bent portion formed by bending an end on the side of the opening inward; A current collector plate coupled to one surface of the electrode assembly and electrically connected to the first electrode of the electrode assembly; and A cap coupled to the above-mentioned bending portion and covering the opening of the housing; A battery cell characterized in that a portion of the above current collector plate is joined to a bending portion of the above housing.

2. In paragraph 1, A battery cell characterized in that the above current collector plate has a first connecting portion connected to the electrode assembly and a second connecting portion connected to the bending portion, wherein the second connecting portion is welded to the bending portion in a state of being overlapped by at least two layers through bending.

3. In paragraph 1, A battery cell characterized in that welding is performed while a part of the above current collector plate is interposed between the cap and the bending portion.

4. In paragraph 3, The inner end of the above-mentioned bend is formed in a step manner, A battery cell characterized in that a portion of the above-mentioned current collector is inserted into the stepped portion and placed between the bent portion and the cap.

5. In paragraph 3, The edge of the cap above is provided with a groove that is concave upwards, A battery cell characterized in that a portion of the above current collector plate is inserted into the groove and positioned between the folded portion and the cap.

6. In paragraph 3, The above-mentioned collector plate has a protrusion that protrudes upward in a state of being overlapped in two layers by bending, A battery cell characterized in that welding is performed in a state in which the protrusion is interposed between the cap and the bending portion.

7. In paragraph 6, A battery cell characterized in that the edge portion of the above-mentioned current collector plate is in contact with the lower surface of the above-mentioned bending portion, and the edge of the above-mentioned cap is in contact with the upper surface of the above-mentioned bending portion, and welding is performed.

8. In paragraph 1, A battery cell characterized in that welding is performed while the edge of the cap is interposed between the bending portion and the current collector plate.

9. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis; A housing that accommodates the electrode assembly through an opening formed on one side and has a bent portion formed by bending an end on the side of the opening inward; and A battery cell comprising a cap coupled to the above-described bending portion, covering the opening of the housing, and electrically connected to the first electrode of the electrode assembly.

10. In paragraph 9, A battery cell characterized in that the cap has an inlet for injecting electrolyte into the interior of the housing.

11. In paragraph 9, A battery cell characterized in that the edge of the cap is joined to the bending portion, and at least a portion of the central portion of the cap protrudes toward the electrode assembly and is joined to the electrode assembly.

12. In paragraph 9, A battery cell characterized in that the cap is located in the inner region of the bending portion and has a break portion for venting.

13. A battery pack comprising a battery cell according to any one of claims 1 to 12.

14. A vehicle equipped with a battery pack as per Article 13.

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