Cylindrical battery cell capable of bottom cooling

Abstract

The present disclosure relates to a cylindrical battery cell having a structure capable of rapid cooling through a cap at a lower end portion of a can. The battery cell includes a can having a sidewall portion extending in an axial direction, an opening present at a first end portion of the sidewall portion in the axial direction, and a bottom portion connected to a second end portion of the sidewall portion in the axial direction; an electrode assembly having a first electrode and a second electrode, the electrode assembly housed in the can; a current collector plate including a central portion and a circumferential portion disposed around the central portion, the current collector plate electrically connected to the electrode assembly; and a cap covering the opening of the can, and including a body portion and an edge portion, wherein the bottom portion includes at least one notching vent portion, wherein the central portion is electrically connected to a second electrode of the electrode assembly, wherein the circumferential portion contacts the first end portion of the sidewall portion and the edge portion of the cap, and wherein the first end portion of the sidewall portion, the edge portion of the cap and the circumferential portion are electrically connected to each other.

Description

Cylindrical battery cells with bottom cooling

[0001] The present invention relates to a cylindrical battery cell, and more particularly, to a cylindrical battery cell having a structure that enables smooth cooling through a cap provided at the bottom of a can.

[0002] This application claims priority to Korean Application No. 10-2024-0075533, filed June 11, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] With the proliferation of electric vehicles, the capacity of cylindrical battery cells, manufactured using cylindrical battery cans as housings, is increasing. Furthermore, as battery cell sizes increase, it has become possible to position both the first and second electrode terminals on the top surface of a cylindrical battery cell. With both electrode terminals positioned on the top of the battery cell, multiple cylindrical battery cells can be mounted vertically, and bus bars for both electrode terminals can be positioned on top of the battery cells, further simplifying the structure of vehicle battery packs.

[0004] Referring to Fig. 1, a can (10) of a conventional large-capacity cylindrical battery cell has a bottom member (12) positioned at the top and an opening formed at the lower end of a side wall member (11). A first electrode terminal (17) is sealedly installed in the center of the bottom member (12) with a terminal gasket (170) interposed therebetween.

[0005] In a state where the electrode assembly (20) is accommodated inside the can (10), the first collector plate (30) bonded to the first electrode of the electrode assembly (20) is electrically connected by being bonded to the first electrode terminal (17), and the second collector plate (40) bonded to the second electrode of the electrode assembly (20) is electrically connected by being bonded to the beading portion (113) formed at the lower end of the side wall member (11) of the can (10). Accordingly, the bottom member (12) and the side wall member (11) can form a second electrode terminal (14).

[0006] The cap (16) is attached to the lower end of the side wall member (11) to close the opening of the can (10). The edge of the cap (16) is installed by compression between the beading portion (113) and the crimping portion (115) of the side wall member (11) with the cap gasket (15) interposed therebetween. The cap (16) is not charged by the cap gasket (15) and can thus be non-polar.

[0007] However, since the cap (16) of such a battery cell is placed at the bottom of the can (10) and the air gap between the cap (16) and the electrode assembly (20) acts as a kind of insulating layer, it is impossible to cool the battery cell from the bottom when the battery cell is installed in a battery pack in an upright position.

[0008] Accordingly, the battery cell structure described above inevitably requires side cooling via the sidewall member (11). This limitation in battery cell cooling significantly limits the design freedom of the battery pack. For example, it prevents the application of a battery pack structure that allows bottom cooling.

[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 both the first electrode terminal and the second electrode terminal are positioned at the top, while allowing bottom cooling.

[0010] The present invention aims to provide a battery cell having a high energy density.

[0011] The present invention aims to provide a battery pack in which both the first electrode terminal and the second electrode terminal of the battery cell built in the battery pack are disposed at the top and bottom cooling is possible, and an automobile equipped with the battery pack.

[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, can be applied to a cylindrical battery cell in which both the first electrode terminal and the second electrode terminal are provided at the axial first end.

[0014] The above battery cell may have a can having a side wall member extending in the axial direction, an opening provided at a first end of the side wall member, and a bottom member connected to a second end of the side wall member.

[0015] The above can may be cylindrical.

[0016] The above battery cell may be electrically insulated from the can and may have a first electrode terminal installed through a hole provided in the can.

[0017] The above first electrode terminal may be placed in the central portion of the floor member.

[0018] The above battery cell may include an electrode assembly having a first electrode and a second electrode, accommodated in the can, and supported by a surface facing the bottom member being in contact with the bottom member.

[0019] The above floor member may include at least one notching vent portion.

[0020] The battery cell may include a cap that blocks the opening of the can and includes a body portion and an edge portion.

[0021] The above electrode assembly may have a structure in which a separator is interposed between the first electrode and the second electrode and is wound around a core hollow portion extending in the axial direction.

[0022] The battery cell may include a first electrode plate including a first electrode connection portion electrically connected to a first electrode of the electrode assembly, and a first terminal connection portion electrically connected to the first electrode terminal.

[0023] The battery cell may include a central portion and a peripheral portion disposed around the central portion, and may include a current collector electrically connected to the electrode assembly. The current collector may be a second current collector. The central portion may include a second electrode connection portion electrically connected to a second electrode of the electrode assembly, and the peripheral portion may include a second terminal connection portion disposed radially outward of the second electrode connection portion. The second current collector may include a step portion disposed radially outward of the second electrode connection portion and axially outwardly offset from the second electrode connection portion, and may include a radially extending bridge, and the second terminal connection portion extending axially outwardly from a radially outward end of the bridge.

[0024] The outer surface of the above second terminal connection part can be in contact with the inner surface of the side wall member.

[0025] The axial end of the second terminal connection part can be in contact with the edge of the cap in the axial direction.

[0026] The thickness of the above edge portion is thinner than the thickness of the above body portion,

[0027] The above edge portion may be provided in a section corresponding to a radially outer portion of the step portion of the bridge of the second collector plate in the radial direction.

[0028] The battery cell may be electrically insulated from the can and may include a first electrode terminal installed through a hole provided in the can.

[0029] The first end of the side wall member, the edge of the cap, and the peripheral portion may be electrically connected to each other. The first end of the side wall member, the edge of the cap, and the peripheral portion of the current collector may be welded to each other.

[0030] The above notching vent portion may have a thickness that is reduced compared to the thickness of the adjacent floor member.

[0031] By welding, the outer surface of the edge of the cap and the inner surface of the side wall member facing each other in the radial direction can be joined.

[0032] The edge of the above cap can be electrically connected by welding to the periphery of the second collector plate.

[0033] The present invention provides a battery pack comprising the above-described battery cell and a pack case containing the battery cell.

[0034] The battery cell may be embedded in the pack case such that the cap is in contact with the bottom of the pack case and the first electrode terminal faces upward.

[0035] A cooling structure for cooling the battery cell through the cap of the battery cell may be provided on the bottom of the pack case.

[0036] The present invention provides a vehicle equipped with the above-described battery pack and driven by power from the battery pack.

[0037] In the battery cell of the present invention, the first electrode terminal is installed in an insulating and sealed manner on the bottom member of the can placed at the top, so that both the first electrode terminal and the second electrode terminal are placed at the top.

[0038] The present invention has a structure in which cooling of the bottom of the electrode assembly is possible because the surface of the electrode assembly facing the cap arranged at the bottom comes into contact with the cap at the bottom of the battery cell.

[0039] In the battery cell of the present invention, since the second electrode is bent radially inward at the second end of the electrode assembly and contacts the cap through the second collector plate, heat generated in the electrode assembly can be quickly dissipated toward the lower part of the battery cell by sequentially passing through the second electrode, the second collector plate, and the cap.

[0040] The battery cell of the present invention can be made thick by arranging a notching vent part in the bottom member arranged at the top, so that the cap arranged at the bottom can be made thick, thereby increasing the bulging resistance of the cap against the internal pressure of the can, and heat conduction can be smoothly achieved through the thick cap, so that cooling can be easily achieved through the bottom.

[0041] In the battery cell of the present invention, the thickness of the edge of the cap is relatively thinner than that of the body, and the peripheral portion of the second collector plate is arranged axially offset from the electrode assembly, so that most of the heat generated when welding the cap is transferred to the thick cap, and also the phenomenon of the heat of the peripheral portion of the second collector plate being transferred to the electrode assembly can be reduced, thereby minimizing the influence of the welding heat on the electrode assembly.

[0042] A battery pack equipped with a battery cell of the present invention can apply a lower cooling structure.

[0043] 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.

[0044] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the contents of the invention described above, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters described in these drawings. Meanwhile, the shape, size, scale, or ratio of elements in the drawings included in this specification may be exaggerated to emphasize a clearer explanation.

[0045] Figure 1 is a cross-sectional view showing a comparative form of a cylindrical battery cell.

[0046] Figure 2 is an exploded perspective view of the electrode assembly accommodated inside the can of Figure 1 before winding.

[0047] Fig. 3 is a perspective view of the electrode assembly of Fig. 2 in a pre-winding laminated state.

[0048] Fig. 4 is a perspective view of an assembled cylindrical jelly-roll-shaped electrode assembly by winding up the laminate of Fig. 3.

[0049] Figure 5 is a perspective view showing a state in which the first collector plate is joined to the electrode assembly.

[0050] Figure 6 is a perspective view showing a state in which a second collector plate is joined to an electrode assembly.

[0051] Figure 7 is a cross-sectional view showing an electrode assembly inserted into a can so that the first collector plate faces and makes contact with the bottom member and the second collector plate is positioned toward the opening.

[0052] Figure 8 is a cross-sectional view showing the state in which the second collector plate, the side wall member near the opening, and the edge of the cap are joined.

[0053] FIG. 9 is a drawing showing a battery pack having the battery cell of FIG. 8 built into a pack housing.

[0054] Fig. 10 is a drawing showing a vehicle equipped with the battery pack of Fig. 9.

[0055] Hereinafter, the present invention will be described in detail with reference to the drawings. Terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concept of a term to best explain his or her invention, they should be interpreted in the sense and concept that conforms to the technical spirit of the present invention.

[0056] Accordingly, the embodiments described in this specification and the configurations described in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0057] Additionally, throughout the specification, whenever a part is said to “include,” “comprise,” “have,” or “have” a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0058] In addition, the terms 'about', 'substantially', etc. used throughout this specification are used in the sense of or near to the numerical values ​​when manufacturing and material tolerances inherent to the meanings stated are presented, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure where exact or absolute values ​​are mentioned to aid understanding of this specification.

[0059] In this specification, terms such as "upper," "lower," "left," "right," "inner," and "outer" refer to positions or directions within the referenced drawings and should not be limiting. The terms "inner" and "outer" refer to directions toward or away from the geometric center of the designated device, system, or its components, respectively. These terms include the words listed above, their derivatives, and words of similar meaning.

[0060] In this specification, when it is said that a member is located “on” another member, this includes not only cases where a member is in contact with another member, but also cases where another member exists between the two members.

[0061] 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.

[0062] 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.

[0063] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0064] 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.

[0065] 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 other components.

[0066] 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.

[0067] 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.

[0068] 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.

[0069]

[0070] Hereinafter, a battery cell according to one aspect of the present invention will be described with reference to the drawings.

[0071] Referring to FIGS. 2 to 8, a 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). The battery cell may be a cylindrical battery cell.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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).

[0076] In the above-mentioned blank portion (26), notches can be formed at a predetermined interval to form flag-shaped notching tabs (27).

[0077] 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.

[0078] 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.

[0079] 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.

[0080] In addition, in the embodiment, a structure is exemplified in which a notching tab (27) is deleted in a predetermined section of the centripetal end of the above-mentioned plain 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 centripetal end of the plain portion, the notching tab may not be deleted in the centrifugal end of the plain portion, or neither may be deleted.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] The above-mentioned collector plate (30, 40) can be manufactured by punching, trimming, piercing, and bending a metal sheet.

[0088] Referring to FIG. 5, the first collector plate (30) includes a first terminal connection portion (32) provided at a portion corresponding to the core hollow portion (29) of the electrode assembly (20), and a first electrode connection portion (31) provided around the first terminal connection portion (32). The first electrode connection portion (31) is arranged at the center of the first collector plate (30) and is provided in a form that covers at least a portion of the core hollow portion (29) of the electrode assembly (20) in the axial direction. The first electrode connection portion (31) is spaced apart from the first terminal connection portion (32) in the radial direction and is arranged in a radially extended form. A plurality of the first electrode connection portions (31) are arranged spaced apart from each other along the circumferential direction.

[0089] The first terminal connection portion (32) and the first electrode connection portion (31) are physically and electrically connected to each other through a conductive portion (33). The conductive portion (33) includes a radial extension portion (331) extending radially from the first electrode connection portion (31), and a circumferential extension portion (332) extending circumferentially from a centrifugal end of the radial extension portion. The radial extension portion (331) is spaced apart from the first electrode connection portion (31) in a circumferential direction and alternately arranged. The circumferential extension portion (332) is connected to the centrifugal end of the first electrode connection portion (31).

[0090] The above first electrode connection part (31) is joined to the notched tab (27) of the first electrode of the electrode assembly (20) by laser welding or the like before being placed in the electrode assembly (20) can. The welding line of the laser may extend radially.

[0091]

[0092] Referring to Fig. 6, the second collector plate (40) includes a central portion, a bridge, and a peripheral portion.

[0093] The central portion is electrically connected to the electrode assembly. The peripheral portion is arranged around the central portion.

[0094] The central portion includes a second electrode connection portion (41) including a ring-shaped ring portion (410) having a hole formed in the center and an extension portion (411) extending radially outward from the ring portion (410). In addition, the second collector plate (40) includes a bridge (43) having a centripetal end connected to the ring portion (410) and extending radially from the ring portion. In addition, the peripheral portion includes a second terminal connection portion (42) in the shape of an outer ring connected to a centrifugal end of the bridge (43). That is, it is disposed radially outwardly of the second electrode connection portion.

[0095] The second electrode (22) and the second collector plate (40) are electrically connected to each other by being joined through a laser welding line extending radially along the expansion portion (411) and the ring portion (410).

[0096] The above bridge (43) is arranged between the expansion portions (411) in the circumferential direction. The above bridge (43) has a stepped portion (430) so that at least a portion of the bridge (43) and the second terminal connection portion (42) are offset axially outward.

[0097] The above second terminal connection portion (42) has a ring shape in the shape of an “L” cross section that extends radially outward and then extends axially again from its end.

[0098] The second electrode connection portion (41) may be joined to the notched tab (27) of the second electrode (22) of the electrode assembly (20) by laser welding or the like before placing the electrode assembly (20) into the can (10). The welding line of the laser may extend radially.

[0099]

[0100] Referring to Fig. 7, the can (10) includes a side wall member (11) extending axially between a first end and a second end, and a bottom member (12) connected to the second end of the side wall member (11) and extending radially. The first end of the side wall member (11) is open to define an opening of the can (10).

[0101] The above opening can be sealed by covering it with a cap (16) after accommodating the electrode assembly (20) in the can (10).

[0102] The above floor member (12) may have a disc shape, and the side wall member (11) may have a circular tube shape.

[0103] The above-mentioned bottom member (12) and side wall member (11) can be manufactured by forming a metal sheet with a nickel plated surface using a deep drawing process, and trimming the front end of the side wall member (11) with a punch while holding it with a blank holder. Of course, the material of the can (10) is not limited to this.

[0104] A hole is provided in the center of the above-described bottom member (12), and a first electrode terminal (17) can be fitted into the hole. The first electrode terminal (17) can be fixed to the bottom member (12) by being riveted while a terminal gasket (170) is interposed therebetween. The terminal gasket (170) is interposed between the first electrode terminal (17) and the bottom member (12), sealing the inside and the outside with the bottom member (12) as the boundary, preventing leakage of the electrolyte, and electrically insulating the first electrode terminal (17) and the bottom member (12).

[0105] However, the method of connecting the first electrode terminal (17) and the can (10) is not limited to this. For example, if the structure is such that the first electrode terminal (17) and the can (10) can be sealed and electrically insulated, various other fixing methods, such as a bolt-nut connection method, a glass seal method, or a chrome coating & PP-MAH thermal bonding method, can also be applied.

[0106] Considering that the cap (16) is relatively thick, the vent of the battery cell (72) can be formed through the bottom member (12). To this end, the bottom member (12) includes a notched vent portion (123). The notched vent portion (123) is a region whose thickness is reduced compared to the thickness of the adjacent bottom member. At least one notched vent portion (123) may be included. The notched vent portion (123) is a portion in which the thickness of the bottom member (12) is reduced to weaken the strength. Accordingly, when the internal pressure of the battery cell increases, the notched vent portion (123) is broken and the bottom member (12) is opened, thereby preventing an explosion of the battery cell.

[0107] The above notching vent portion (123) may be formed in an “O” or “C” shape in the circumferential direction of the bottom member. The first electrode terminal (17) may have a first polarity, and the can (10) may have a second polarity.

[0108] Accordingly, both the first electrode terminal (17) and the second electrode terminal (14), which is the bottom member (12), can be positioned at the second end of the battery cell. Accordingly, both the bus bar connected to the first electrode terminal (17) of the battery cell and the bus bar connected to the second electrode terminal (14) can be positioned at the upper portion of the battery cell.

[0109] In one example, the first electrode terminal (17) may be a positive terminal and the second electrode terminal (14) may be a negative terminal. Of course, the opposite may also be true.

[0110] The electrode assembly (20) is accommodated in the can (10) in a state where the first collector plate (30) is aligned toward the bottom member (12) of the can (10). In addition, an insulator (19) is interposed between the first collector plate (30) and the bottom member (12) to electrically insulate them from each other.

[0111] The first electrode terminal (17) fixed to the can (10) can be fixed and electrically connected by being joined to the surface of the first terminal connection portion (32) of the first current collector (30) by a thermal bonding method such as welding. The first electrode terminal (17) and the first terminal connection portion (32) of the can (10) can be connected after the electrode assembly (20) is placed in the can (10).

[0112]

[0113] Referring to Fig. 8, a cap (16) blocks an opening provided at a first end of the can. The cap (16) includes a body portion (165) disposed at a central portion, and an edge portion (160) connected to a periphery of the body portion (165). The body portion (165) is formed to be thicker than the edge portion (160). The edge portion (160) can be electrically connected to the first end of the side wall member (11) and the periphery of the current collector (40).

[0114] The edge portion (160) of the cap (16) is provided in a section corresponding to the outer portion of the step portion (430) of the second collector plate (40) in the radial direction. In this way, the profile of the axial inner surface of the cap (16) can be complementary to the profile of the axial outer surface of the second collector plate (40). On the other hand, the axial outer surface of the cap (16) is configured to be flat.

[0115] The second terminal connection portion (42) of the second collector plate (40) includes a portion extending axially outward, and its outer circumference is joined to the inner circumference of the side wall member (11). In addition, a predetermined step portion is provided on the inner circumference of the side wall member (11), and the axial inner end of the second terminal connection portion (42) can interfere with the step portion in the axial direction.

[0116] The edge portion (160) of the cap (16) includes a plate mating portion (163) that is in axial contact with at least the axial outer end of the second terminal connection portion (42) of the second collector plate (40), and a can mating portion (161) that is in radial contact with the inner surface of the side wall member (11).

[0117] The side wall member (11) may be provided with an inner diameter expansion portion (114) at the first end. The inner diameter expansion portion (114) may have a lateral step shape arranged along the radially inner surface of the side wall member (11). Accordingly, the radially inner surface of the side wall member (11) may include a first inner surface (115) that is arranged axially inwardly than the inner diameter expansion portion (114), that is, further from the opening of the open end of the side wall member (11), and a second inner surface (116) that is arranged axially outwardly than the inner diameter expansion portion (114), that is, closer to the opening of the open end of the side wall member (11).

[0118] The second inner side surface (116) may have an inner diameter larger than that of the first inner side surface (115). Accordingly, the side wall member (11) may have a second thickness measured in the radial direction at a portion where the second inner side surface (116) is provided that is thinner than the first thickness measured in the radial direction at a portion where the first inner side surface (115) is provided.

[0119] The outer peripheral surface of the second collector plate (40) (e.g., the outer peripheral surface of the second terminal connection portion) is electrically connected to the inner peripheral surface of the side wall member (11) (e.g., the inner surface of the first end portion). For example, the outer peripheral surface of the second collector plate (40) may be in contact with the inner diameter expansion portion (114) and the second inner surface (116).

[0120] The side wall member (11) has an overhang portion (113) that protrudes further outward in the axial direction than the cap (16). By irradiating a laser to the area where the cap (16), the can (10), and the second collector plate are in contact with each other, including the overhang portion (113), and performing seam welding, a triple-welded weld portion (18) can be formed. That is, the first end portion of the side wall member (11), the edge portion (160) of the cap, and the periphery of the second collector plate (40) can be welded to each other. By this weld portion (18), the second collector plate (40), the side wall member (11), and the cap (16) can all be fixed to each other and electrically connected, and the abutting portion of the side wall member (11) and the cap (16) can be sealed.

[0121] Meanwhile, before covering the opening with the cap (16), electrolyte may be injected into the interior of the can (10). The opening is covered with the cap (16) after the electrolyte is injected. Of course, the electrolyte may be injected through a separate injection port after the opening is covered with the cap (16).

[0122] The axial inner surface of the cap (16) has a shape complementary to that of the second collector plate (40), while the axial outer surface of the cap (16) is flat. Accordingly, heat generated in the electrode assembly (20) can be smoothly released to the lower portion of the battery cell (72) through the second collector plate (40) and the cap (16).

[0123] The above battery cell (72) can be accommodated in a pack housing (71) of a battery pack (70) as illustrated in FIG. 9. 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.

[0124] 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.

[0125] 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. 10, the vehicle's mileage relative to its energy consumption can be further increased.

[0126] Even if the above battery cell (72) generates heat in the electrode assembly (20), this heat is quickly dissipated downwards through the second electrode (22), the second collector plate (40), and the cap (16). 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.

[0127]

[0128] 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.

[0129] 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 member extending in an axial direction, an opening provided at the first axial end of the side wall member, and a bottom member connected to the second axial end of the side wall member; An electrode assembly having a first electrode and a second electrode and accommodated in the can; A current collector plate including a central portion and a peripheral portion arranged around the central portion, and electrically connected to the electrode assembly; and A cap that blocks the opening of the can and includes a body portion and an edge portion; The above floor member includes at least one notching vent portion, The central portion is electrically connected to the second electrode of the electrode assembly, The above circumference is in contact with the first end of the side wall member and the edge of the cap, A battery cell, wherein the first end of the side wall member, the edge of the cap, and the peripheral portion are electrically connected to each other.

2. In claim 1, A battery cell wherein the notched vent portion has a thickness reduced compared to the thickness of the adjacent bottom member.

3. In claim 1, The above current collector plate is a second current collector plate, the central portion includes a second electrode connection portion electrically connected to the second electrode of the electrode assembly, and the peripheral portion includes a second terminal connection portion arranged radially outside the second electrode connection portion. A first electrode terminal electrically insulated from the can and installed through a hole provided in the can; and A battery cell further comprising a first electrode plate including a first electrode connecting portion electrically connected to the first electrode of the electrode assembly, and a first terminal connecting portion electrically connected to the first electrode terminal.

4. In claim 3, A battery cell, wherein the second collector plate includes a step portion that is positioned radially outside the second electrode connecting portion and is axially offset from the second electrode connecting portion, the step portion including a radially extending bridge, and the second terminal connecting portion extending axially outside from a radially outer end of the bridge.

5. In claim 3, A battery cell in which the outer surface of the second terminal connection portion is in contact with the inner surface of the side wall member.

6. In claim 3, A battery cell, wherein the axial end of the second terminal connection portion is in contact with the edge of the cap in the axial direction.

7. In claim 4, The thickness of the above edge portion is thinner than the thickness of the above body portion, The above edge portion is provided in a section corresponding to a radially outer portion of the step portion of the bridge of the second collector plate in the radial direction, wherein the battery cell.

8. In claim 1, A battery cell in which the first end of the side wall member, the edge of the cap, and the periphery of the current collector plate are welded to each other.

9. In claim 8, A battery cell in which the outer surface of the edge portion of the cap and the inner surface of the side wall member, which face each other in the radial direction, are joined by the above welding.

10. In claim 1, A battery cell having a structure in which the electrode assembly is wound around a core hollow portion extending in the axial direction, with a separator interposed between the first electrode and the second electrode.

11. A battery pack comprising a battery cell according to any one of claims 1 to 10 and a pack case containing the battery cell.

12. In claim 11, A battery pack wherein the battery cell is built into the pack case such that the cap is in contact with the bottom of the pack case and the first electrode terminal faces upward.

13. In claim 12, A battery pack, wherein a cooling structure for cooling the battery cell through the cap of the battery cell is provided on the bottom of the pack case.

14. A vehicle equipped with the battery pack of claim 11 and driven by power from the battery pack.