Battery cell installed with electrode terminal and battery assembly including same

Abstract

Provided are a battery cell and a battery assembly comprising same. The electrode terminal is installed to pass through a through-hole provided in the end wall of a can and comprises: a head portion and a shoulder portion disposed on the outside and inside of the end wall, respectively; and a neck portion connecting the head portion and the shoulder portion in the axial direction. The neck portion is inserted into the through-hole. The bottom surface of the head portion compresses the terminal gasket together with the outer surface of the end wall. The head portion has a slope section in which the thickness measured in the axial direction gradually increases from the radially outer edge to the radially inner side.

Description

Battery cell with electrode terminal installed and battery assembly including the same

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0108593, dated August 13, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery cell having an electrode terminal installed, and more specifically, to a battery cell and a battery assembly including the same, wherein the electrode terminal protruding from the housing of the battery cell has high deformation resistance against an axial inward impact, thereby preventing a short circuit from occurring.

[0003] With the recent surge in demand for secondary batteries, various forms of secondary batteries are being developed. Cylindrical battery cells, which house a jelly-roll-shaped electrode assembly within a cylindrical metal can, are more shock- and temperature-resistant than pouch-type batteries. Consequently, demand for can-shaped cells for use in vehicle battery packs is growing.

[0004] Conventional can-shaped battery cells electrically connect the electrodes and the can or terminals by bonding a separate tab member to the current collector of the electrode assembly and bonding the tab member to the can or terminal. However, in battery cells with this structure, the structure for electrically connecting the electrodes and terminals takes up a significant amount of internal space within the can. Furthermore, this electrical connection structure has limitations in reducing internal resistance because the current path is limited to the tab member. An electrical connection structure that makes it difficult to reduce internal resistance is unsuitable for application to large-capacity battery cells that carry high currents.

[0005] Recently, cylindrical battery cells have been developed with increasing volume to increase energy capacity. Furthermore, technological development is being focused on maximizing the internal space of cylindrical battery cells, maximizing the volume of the electrode assembly housed within the internal space.

[0006] Accordingly, a structure has recently been developed in which a non-coated portion of the current collector is exposed to the axial end of the electrode assembly, folded in a radial direction so that the folded non-coated portion forms a flat surface facing the axial direction, a current collector plate is welded to the surface, and the current collector plate is again joined to a can or a rivet terminal. According to this structure, the current path between the electrode and the can or terminal is widened to lower the internal resistance, while the space inside the can occupied by the electrical connection structure between the electrode and the can or terminal is minimized, thereby further increasing the energy density of the battery cell.

[0007] In addition, in a battery cell of this structure, the rivet terminal provided at the axial first end of the can and the end wall of the can can constitute a first electrode terminal and a second electrode terminal, respectively, so that all bus bars electrically connected to the battery cell can be placed on the upper part of the battery cell.

[0008] However, since the axial gap between the rivet terminal and the electrode assembly housed inside the can is small in these recent battery cell structures, there is a risk that if the rivet terminal receives an external impact and sinks inward of the can together with the end wall, the rivet terminal may come into contact with the second electrode of the electrode assembly housed inside the can, resulting in a short circuit.

[0009] The present invention has been devised to solve the above-described problem, and aims to provide a battery cell capable of minimizing the extent to which an electrode terminal is displaced inside a can even when subjected to an external impact.

[0010] The purpose of the present invention is to provide a battery cell capable of minimizing the amount of deformation occurring in a can portion connected to an electrode terminal due to an external impact applied to the electrode terminal.

[0011] The purpose of the present invention is to provide a battery assembly that can have a compact structure even when the protruding height of the electrode terminal of a battery cell is increased to reinforce the rigidity of the electrode terminal.

[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 can be applied to a battery cell comprising an electrode assembly having a first electrode and a second electrode, a can accommodating the electrode assembly, and an electrode terminal penetrating the can and electrically connected to the first electrode, wherein a portion of the can around the electrode terminal is electrically connected to the second electrode and can be used as an electrode terminal of the second electrode.

[0014] The can has a side wall extending axially and surrounding an internal space that accommodates the electrode assembly, and an end wall extending radially so as to intersect the axial direction and having an edge connected to an axial first end of the side wall.

[0015] The above electrode terminal is installed on the end wall. A through hole is formed at a position radially inward from the side wall on the end wall.

[0016] The above electrode terminal passes through the through hole and is installed on the end wall.

[0017] The above end wall is electrically connected to the second electrode.

[0018] The battery cell includes a terminal gasket that is press-fitted between the electrode terminal and the end wall to seal a gap between the electrode terminal and the end wall and electrically insulate the electrode terminal from the end wall.

[0019] The electrode terminal includes a head portion arranged on the outside of the end wall, a neck portion extending axially inward from the head portion and passing through the through hole, and a shoulder portion arranged on the inside of the end wall.

[0020] The terminal gasket may be interposed between the head portion and the outer surface of the end wall, between the net portion and the inner surface of the end wall defining the through hole, and between the shoulder portion and the inner surface of the end wall.

[0021] The radially outer edge of the above head portion is positioned radially outer than the through hole.

[0022] The shoulder portion extends radially outward from the neck portion. The radially outer edge of the shoulder portion is positioned radially outward from the through hole.

[0023] The surface of the neck portion and / or shoulder portion facing axially inward may provide a surface that can be connected to the first electrode.

[0024] The electrode assembly may further include a current collector connecting the first electrode and the electrode terminal.

[0025] The central portion of the current collector plate is joined to the electrode terminal, and the peripheral portion of the current collector plate surrounding the central portion can be joined to the first electrode exposed to the axial first end of the electrode assembly.

[0026] An insulator that electrically insulates the end wall and the electrode assembly from each other may be interposed between the axial first end of the electrode assembly and the inner surface of the end wall.

[0027] The lower surface of the above head portion presses the terminal gasket together with the outer surface of the end wall.

[0028] The above head portion has a slope section in which the thickness measured in the axial direction gradually increases from the radially outer edge toward the radially inner side.

[0029] In a partial example, the rate of increase in thickness may decrease as one moves radially inward in the above slope section.

[0030] In a partial example, the surface of the above slope section may provide an upwardly convex surface.

[0031] In a partial example, the rate of increase in thickness may be constant as one goes radially inward in the above slope section.

[0032] In a partial example, the surface of the above slope section may have a constant slope.

[0033] In a partial example, the slope section may be arranged radially over the entire section of the head portion.

[0034] In a partial example, a flat section with a flat surface may be provided radially inward from the slope section in the head section.

[0035] In a partial example, the slope section may be positioned outside the inner surface of the end wall defining the through hole in the radial direction, including a position corresponding thereto.

[0036] In a partial example, the slope section may be positioned radially outward from and including the edge of the neck portion.

[0037] For a length of the head portion extending radially outwardly further than the through hole, a ratio of the thickness of the head portion measured at a position corresponding to the edge of the through hole may be 0.4 or more and 0.9 or less.

[0038] The shape of the head portion as viewed in the axial direction may be circular or polygonal.

[0039] The present invention provides a battery assembly having a plurality of battery cells built-in. For example, a battery pack mounted on a vehicle may be manufactured by having a plurality of battery modules built-in, each battery module having a plurality of battery cells built-in. Alternatively, a battery pack mounted on a vehicle may be manufactured in a modular form, omitting the battery module structure and directly having a plurality of battery cells built-in. The battery assembly may refer to a battery module having a plurality of battery cells built-in, a battery pack having a plurality of such battery modules built-in, or a battery pack having a plurality of battery cells directly built-in in a modular form.

[0040] The above battery assembly may further include a bus bar that electrically connects electrode terminals of the plurality of battery cells to each other.

[0041] In a partial example, the bus bar may be joined to the slope section of the head portion.

[0042] In a partial example, the bus bar portion joined to the slope section may be positioned axially inward from the top of the head portion.

[0043] In a partial example, the busbar may not cover a flat section having a flat surface radially inward from the slope section of the head portion.

[0044] According to the present invention, in order to suppress deformation of the electrode terminal when the electrode terminal is impacted, the thickness of the head portion is further secured, and the thickness of the head portion is secured at least in an area corresponding to the neck portion in the radial direction, so that the neck portion can be suppressed from being greatly deformed inward in the axial direction.

[0045] According to the present invention, the upper corner of the edge of the head portion is prevented from protruding due to the slope section, thereby preventing the electrode terminal from colliding with an external object, and the rigidity of the head portion is gradually increased toward the radial inward direction, thereby evenly deforming the slope section and the end wall portion of the can facing the slope section when subjected to an external impact, thereby suppressing or minimizing displacement of the electrode terminal.

[0046] According to the present invention, by arranging the location where the bus bar is connected to the electrode terminal of the battery cell on the surface of the slope section, the bus bar, which does not affect the displacement and deformation resistance of the electrode terminal, does not occupy the overall height of the battery assembly, thereby making it possible to design the battery assembly more compactly.

[0047] According to the present invention, even if the upper part of the electrode terminal is impacted, the impact is not applied to the joint portion of the bus bar and the electrode terminal, so that the joint portion of the bus bar and the electrode terminal is not damaged.

[0048] 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.

[0049] FIG. 1 is an exploded perspective view of an electrode assembly applicable to a battery cell having an electrode terminal according to an embodiment of the present invention.

[0050] Figure 2 is an exploded perspective view of the electrode assembly of Figure 1.

[0051] Figure 3 is a perspective view of an electrode assembly according to an embodiment of the present invention.

[0052] Fig. 4 is a perspective view showing a state in which a first collector plate is joined to the axial first end of the electrode assembly of Fig. 3.

[0053] Figure 5 is a perspective view of a can having an electrode terminal coupled thereto according to an embodiment of the present invention.

[0054] Fig. 6 is a side cross-sectional view showing the electrode assembly inserted into the can of Fig. 5.

[0055] Fig. 7 is an enlarged cross-sectional view showing the end wall portion of the battery cell of Fig. 6.

[0056] Fig. 8 is a cross-sectional view showing an enlarged portion of the electrode terminal portion installed on the end wall of Fig. 7.

[0057] Fig. 9 is a cross-sectional view showing a state in which the first bus bar is connected to the electrode terminal of Fig. 8.

[0058] Fig. 10 is a perspective view showing a battery pack including a battery cell of an embodiment.

[0059] Fig. 11 is an enlarged cross-sectional view of an end wall portion of a battery cell having an electrode terminal of another embodiment.

[0060] Fig. 12 is a cross-sectional view showing an enlarged portion of the electrode terminal portion installed on the end wall of Fig. 11.

[0061] Figure 13 is an enlarged cross-sectional view of an end wall portion of a battery cell having an electrode terminal of another embodiment.

[0062] Fig. 14 is a cross-sectional view showing an enlarged portion of the electrode terminal portion installed on the end wall of Fig. 13.

[0063] [Explanation of symbols]

[0064] 10: Can (housing) 11: Side wall 12: End wall 121: Through hole 13: Beading part 14: Crimping part 15: Electrode terminal 16: Terminal gasket 19: Insulator 20: Electrode assembly 21: First electrode 22: Second electrode 23: Current collector (metal foil) 24: Active material 25: Holding part 26: Non-conductive part 27: Electrode tab (notched tab) 28: Separator 30: First current collector 31: Periphery 33: Center 35: Bridge 40: Second current collector 41: First part 42: Second part 61: Head part 62: Slope section 63: Flat section 64: Neck section 67: Shoulder section 81: First bus bar 82: Second bus bar 90: Battery pack 91: Battery Cell 92: Pack Housing

[0065] 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.

[0066] 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.

[0067] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0068] 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.

[0069] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0070] 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.

[0071] 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.

[0072] In describing the embodiments, the term "axial direction" may refer to the direction in which a pair of terminal members are coupled. The axial direction may refer to the direction in which the axis forming the winding center of the jelly-roll-shaped electrode assembly, i.e., the winding axis, extends. This may be understood as a concept encompassing both directions in which the axis extends.

[0073] In describing the embodiments, the term "radial direction" or "radial direction" refers to a direction approaching or moving away from the axis. This can be understood as a concept that includes both directions approaching or moving away from the axis.

[0074] In describing the embodiment, the circumferential direction or the circumferential direction refers to the direction surrounding the axis.

[0075] Based on the definition of these directions, the width direction of the electrode assembly in the unfolded state corresponds to the axial direction of the jelly roll. The length direction of the electrode assembly in the unfolded state corresponds to the circumferential direction of the jelly roll. And the normal direction to the electrode surface in the unfolded state of the electrode assembly corresponds to the radial direction of the jelly roll.

[0076] Referring to FIGS. 1 to 6 below, the assembly process and structure of a battery cell having a cylindrical can, which is a battery cell having a housing in which an electrode terminal according to an embodiment of the present invention can be installed, will be described.

[0077] The battery cell of the embodiment may be, for example, a cylindrical battery cell having a form factor ratio (defined as the ratio of the diameter of the cylindrical battery cell divided by its height, i.e., the ratio of the diameter to the height) of greater than about 0.4.

[0078] Here, the form factor refers to a value indicating the diameter and height of a cylindrical battery cell. The cylindrical battery cell may be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, a 46800 cell, or a 46950 cell. In the numerical value indicating the form factor, the first two numbers indicate the diameter of the cell, the next two numbers indicate the height of the cell, and the last number 0 indicates that the cross-section of the cell is circular.

[0079] The above battery cell may be a cylindrical battery cell having a roughly cylindrical shape, a diameter of approximately 46 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

[0080] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 48 mm, a height of approximately 75 mm, and a form factor ratio of 0.640.

[0081] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 48 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

[0082] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 48 mm, a height of approximately 80 mm, and a form factor ratio of 0.600.

[0083] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 46 mm, a height of approximately 80 mm, and a form factor ratio of 0.575.

[0084] The present invention can of course also be applied to battery cells having a form factor ratio of approximately 0.4 or less, such as 18650 cells, 21700 cells, etc. For 18650 cells, the diameter is approximately 18 mm, the height is approximately 65 mm, and the form factor ratio is 0.277. For 21700 cells, the diameter is approximately 21 mm, the height is approximately 70 mm, and the form factor ratio is 0.300.

[0085] Referring to FIGS. 5 and 6, the battery cell of the embodiment includes a housing (10) having a side wall (11) extending in the axial direction, an end wall (12) connected to an axial first end of the side wall (11), and an open end or opening provided at an axial second end of the side wall (11). The housing (10) may be a can (10) made of metal.

[0086] The above battery cell has a jelly-roll shaped electrode assembly (20) accommodated in the can (10).

[0087] The above electrode assembly (20) is prepared by preparing a first electrode (21), a second electrode (22), and a separator (28) having a predetermined width and extending in the longitudinal direction as shown in FIG. 1, and forming a laminated body by stacking the first electrode (21), the separator (28), the second electrode (22), and the separator (28) in that order as shown in FIG. 2, and winding this around a core shaft to produce a jelly-roll shape as shown in FIG. 3.

[0088] 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.

[0089] The first electrode (21) and the second electrode (22) are manufactured in the form of a roll sheet that extends in the length direction with a predetermined width. The electrodes (21, 22) are manufactured in the form of forming an active material layer by applying an active material (24) to the surface of a metal foil constituting a current collector (23) and rolling it. The electrodes (21, 22) have a holding portion (25) region where the active material (24) is applied, and a non-coated portion (26) region where the active material (24) is not applied. The first electrode (21) has a non-coated portion (26) region at a first end of the current collector (23) in the width direction, and the second electrode (22) has a non-coated portion (26) region at a second end of the current collector (23) opposite the first end in the width direction.

[0090] Referring to FIGS. 1 and 2, the first electrode (21) and the second electrode (22) are laminated such that their uncoated portions (26) extend further outward in the width direction than the separator (28) at the first and second ends in the width direction of the electrode assembly (20), respectively. Referring to FIG. 3, the uncoated portion (26) of the first electrode (21) protrudes from the axial first end of the rolled jelly-roll, and the uncoated portion (26) of the second electrode (21) protrudes from the axial second end of the jelly-roll. The uncoated portion (26) itself functions as at least one electrode tab (27).

[0091] In the above-mentioned blank portion (26), notches can be formed at a predetermined interval to form flag-shaped notching tabs (27).

[0092] 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.

[0093] 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.

[0094] In addition, as illustrated in FIGS. 1 and 2, the height of the notching tabs (27) gradually increases from the core side to the outer circumference side. However, differently from this, the height of these notching tabs may be implemented in a constant or gradually decreasing form.

[0095] In addition, in the embodiment, a structure is exemplified in which a notching tab (27) is deleted in a predetermined section of the core side end of the above-mentioned plain portion (26) and a predetermined section of the outer side end. However, it is obvious that, contrary to this, the notching tab may not be deleted in the core side end of the plain portion, the notching tab may not be deleted in the outer side end of the plain portion, or the notching tab may not be deleted in both sides.

[0096] In the jelly-roll type electrode assembly (20), the notched tab (27) can be folded and flattened in the radial direction as illustrated in FIG. 3. The notched tab (27) can be folded radially inward or outward. In the embodiment, a structure in which the notched tab (27) is folded radially inward is exemplified.

[0097] The above-mentioned notched tabs (27) may be pre-bent one by one during the process of forming a jelly-roll-shaped electrode assembly (20) by stacking and winding electrodes and separators, and then may be finally bent again after being wound in a jelly-roll shape. Alternatively, the above-mentioned notched tabs (27) may be bent all at once after stacking and winding electrodes and separators to form a jelly-roll-shaped electrode assembly.

[0098] The notching tabs (27) of the first electrode (21) and the notching tabs (27) of the second electrode (22), which are bent in the radial direction and overlapped in multiple numbers in the axial direction, can provide a plane that is substantially perpendicular to the axial direction at the axially opposite ends of the electrode assembly (20).

[0099] A first current collector plate (30) can be joined to a substantially flat surface provided by bending the notched tab (27) exposed to the axial first end of the electrode assembly (20), as shown in FIG. 4.

[0100] Referring to FIG. 4, the first collector plate (30) includes a central portion (33) provided at a position corresponding to the core hollow portion of the electrode assembly (20), a peripheral portion (31) surrounding the central portion (33), and a bridge (35) extending radially to connect the central portion (33) and the peripheral portion (31). The bridge (35) functions as a conductive portion that electrically connects the peripheral portion (31) and the central portion (33). An electrode connection portion welded to a notched tab (27) of the first electrode (21) is provided in the peripheral portion (31). In addition, a terminal connection portion welded to the electrode terminal (15) is provided in the central portion (33).

[0101] In the embodiment, the first collector plate (30) is exemplified as a positive collector plate. The first collector plate (30) may be made of aluminum. However, alternatively, the first collector plate (30) may be a negative collector plate or may be made of copper.

[0102] The above first collector plate (30) can be manufactured by punching, trimming, piercing, or bending a metal sheet or metal plate.

[0103] Referring to Fig. 6, the electrode assembly (20) having the collector plate (30) assembled thereon is accommodated inside the can (10) through an opening provided at the axial second end of the can (10). Prior to inserting the electrode assembly (20) into the can (10), an insulator (19) may be laminated on the inner surface of the end wall (12). The insulator (19) electrically insulates the first collector plate (30) from the end wall (12).

[0104] The end wall (12) of the above can (10) may have a disc shape with a through hole formed in the center, and the side wall (11) may have a circular tube shape surrounding the internal volume of the can (10).

[0105] An electrode terminal (15) can be fitted into the above through hole. The electrode terminal (15) can be fixed to the end wall (12) with a terminal gasket (16) interposed therebetween. The terminal gasket (16) is interposed between the electrode terminal (15) and the end wall (12), thereby sealing the inside and outside of the can (10) to prevent leakage of the electrolyte and electrically insulating the electrode terminal (15) from the end wall (12).

[0106] The above electrode terminal (15) may have a first polarity, and the can (10) may have a second polarity. That is, the end wall (12) of the can (10) and the side wall (11) connected thereto may both have a second polarity.

[0107] Accordingly, the battery cell may have both the first electrode terminal (15) and the second electrode terminal (12) positioned at the axial end, i.e., the closed end, provided with the end wall (12). Then, the battery cell may have both the first bus bar (81) connected to the first electrode terminal (15) and the second bus bar (82) connected to the end wall (12) electrically connected to the second electrode (22) positioned at one axial side (upper) of the battery cell (see FIG. 10).

[0108] In one embodiment, the first electrode terminal (15) may be a positive terminal and the second electrode terminal may be a negative terminal. Of course, the opposite may also be true.

[0109] The electrode assembly (20) is accommodated in the can (10) in a state where the first collector plate (30) is aligned so as to face the end wall (12) of the can (10). An insulator (19) interposed between the first collector plate (30) and the end wall (12) of the can (10) electrically insulates the first collector plate (30) from the end wall (12).

[0110] And, the central portion (33) of the first collector plate (30) is joined to the electrode terminal (15) fixed to the can (10) by resistance welding, ultrasonic welding, laser welding, or the like, to define a terminal connection portion (34). A welding device for welding the first collector plate (30) and the electrode terminal (15) can approach the back surface (the surface facing the electrode assembly (20)) of the central portion (33) of the first collector plate (30) through the core hollow portion of the electrode assembly (20) from the open end of the can (10) to perform welding. Of course, in addition to this, the first collector plate (30) and the electrode terminal (15) can also be joined by brazing or soldering. That is, various methods can be applied to the first collector plate (30) and the electrode terminal (15) as long as they can electrically connect them and fix them to each other.

[0111] In a state where the electrode assembly (20) is accommodated inside the can (10), the electrode tab (27) of the second electrode (22) can be positioned to face the open end of the side wall (11), i.e., the opening of the housing (10).

[0112] A second collector plate (40) may be joined to the electrode tab (27) of the second electrode (22). The second collector plate (40) includes a first portion (41) joined to the electrode tab (27), and a second portion (42) joined to a side wall (11) of the can (10) or / and a cap (not shown) that seals the opening of the can (10). In this way, the second electrode (22) may be electrically connected to the cap or the side wall (11) through the second collector plate, or may be electrically connected directly to the cap without the second collector plate.

[0113] In addition, although not shown in the drawing, the opening of the can (10) can be closed by covering it with a cap. For example, the can (10) can be sealed by joining the edge of the cap and the periphery of the opening of the side wall (11) of the can (10) by welding or the like. In addition, the can (10) can also be sealed by forming a beading portion and a crimping portion on the side wall of the can (10) and compressing and interposing the edge of the cap therebetween.

[0114] Referring to FIGS. 6 to 9 below, the structure of an electrode terminal (15) according to an embodiment of the present invention will be described.

[0115] An electrode terminal (15) is installed in the can (10) by penetrating a through hole (121) provided in an end wall (12) of the can (10). The electrode terminal (15) is electrically connected to a first electrode (21) of an electrode assembly (20) built into the can (10), and the end wall (12) is electrically connected to a second electrode (22) of the electrode assembly (20). In order to prevent a short circuit between the electrode terminal (15) and the end wall (12), the electrode terminal (15) is sealed and insulated and connected to the end wall (12). For this purpose, a terminal gasket (16) is press-fitted between the end wall (12) and the electrode terminal (15). The electrode terminal (15) of the embodiment is exemplified as a rivet terminal. However, the type of the electrode terminal (15) need not be limited thereto.

[0116] The shape of the electrode terminal (15) as viewed in the axial direction may vary. For example, the shape of the electrode terminal (15) may be implemented in various forms such as a circle, a polygon including a regular polygon, an oval, a track shape, etc. In the embodiment, the shape of the electrode terminal (15) is exemplified as being implemented in a circle.

[0117] A through hole (121) is formed in the end wall (12) so that the electrode terminal (15) can pass through. The through hole (121) is provided at a position radially inwardly spaced from the edge of the end wall (12) connected to the side wall (11). In the embodiment, the through hole (121), the end wall (12), and the side wall (11) are implemented in a circular shape. However, their shapes do not necessarily have to be circular.

[0118] The terminal gasket (16) is compressed and interposed between the electrode terminal (15) and the end wall (12) to seal the gap between the electrode terminal (15) and the end wall (12) and electrically insulate the electrode terminal (15) from the end wall (12). In the embodiment, the terminal gasket (16) is implemented in a ring shape. However, the shape of the terminal gasket (16) is not limited thereto, and it is obvious that the shape may be changed to correspond to the shape of the electrode terminal (15) and the through hole (121) that require sealing.

[0119] The electrode terminal (15) of the embodiment includes a head portion (61) arranged on the outer side of the end wall (12), a neck portion (64) extending axially inward from the head portion (61) and passing through the through hole, and a shoulder portion (67) arranged on the inner side of the end wall (12). The terminal gasket (16) is interposed between the head portion (61) and the outer surface of the end wall (12), between the neck portion (64) and the inner peripheral surface of the end wall (12) defining the through hole (121), and between the shoulder portion (67) and the inner surface of the end wall (12).

[0120] The radially outer edges of the head portion (61) and shoulder portion (67) are positioned radially outer of the through hole (121). On the other hand, the radially outer edge of the neck portion (64) is positioned radially inner of the through hole (121).

[0121] The upper surface of the head portion (61) provides an area where the first bus bar (81) is joined. And the lower surface of the neck portion (64) provides an area where the first collector plate (30) is joined. The head portion (61) has a shape that extends radially outward from the axial upper end of the neck portion (64), and the shoulder portion (67) has a shape that extends radially outward from the neck portion (64) within the can (10).

[0122] The above shoulder portion (67) can be formed by plastically deforming the axially extended plastic processing portion through the through hole (121) and then radially outward by means of caulking, riveting, etc.

[0123] In the embodiment, the shapes of the head portion (61) and the neck portion (64) when viewed in the axial direction are implemented as a circle, and the shape of the shoulder portion (67) is implemented as a ring. However, as already explained, the shapes are not limited thereto.

[0124] The lower surface of the above head portion (61) presses the terminal gasket (16) in the axial direction together with the outer surface of the end wall (12).

[0125] The above head portion (61) has a slope section (62) in which the thickness measured in the axial direction gradually increases from the radially outer edge toward the radially inner side. The slope section (62) is provided in a form in which the rate of increase in thickness decreases toward the radially inner side.

[0126] In the embodiment, the bottom surface of the slope section (62) of the head portion (61) is flat, and the surface of the slope section (62) provides an upwardly convex curved surface.

[0127] The above slope section (62) is provided in the radial direction over the entire section of the head portion (61). Then, as illustrated, the upper surface of the head portion (61) can form an overall convex curve. According to this head portion shape, even if an object collides with the head portion (61) in the radial direction, the object collides with the curved surface and is deflected, thereby minimizing the impact of the head portion (61) on the object. In addition, as illustrated in FIG. 9, even if an object collides with the head portion (61) in the axial direction and an external force (F) is applied to the head portion (61), the stress generated in the electrode terminal by the external force is appropriately distributed by the water drop-shaped shape of the head portion (61).

[0128] According to the shape of the above head portion (61), since the thickness of the center (O) portion together with the neck portion (64) is the thickest, the phenomenon of the electrode terminal (15) itself being bent downward toward the center (O) can be suppressed.

[0129] In addition, since the section of the head portion (61) that overlaps the end wall (12) in the radial direction becomes gradually thinner as it goes outward in the radial direction, as shown in FIG. 9, when an external force (F) is applied to the head portion (61), the stress is evenly distributed in the overlapping section of the head portion (61) and the end wall (12), so that the head portion (61) and the end wall (12) are evenly sagging and deformed. Therefore, it is possible to suppress the displacement of the electrode terminal (15) from being pushed inward in the axial direction from increasing.

[0130] Referring to Fig. 8, preferably, the ratio of the thickness (T) of the head portion (61), measured at a position corresponding to the edge of the through hole (121), to the length (D) of the head portion (61) that extends radially outward more than the through hole (121), may be 0.4 or more and 0.9 or less. When the electrode terminal (15) installed on the end wall (12) of the battery cell (91) is configured at this ratio, the sagging deformation of the head portion (61) and the end wall (12) can occur more evenly.

[0131] Unlike the embodiment, if the slope section (62) is not provided at the edge of the head portion (61) and the entire radial section of the head portion is considerably thick, the deformation of the electrode terminal (15) itself, which causes the center (O) portion to sag when an external force (F) is applied in the axial direction, can be suppressed, but the phenomenon of stress being concentrated in the portion of the end wall (12) that faces the edge of the head portion (61) in the axial direction and the sagging deformation being concentrated in the relevant portion cannot be avoided, and as a result, the electrode terminal (15) cannot help but be greatly pushed inward in the axial direction. In addition, such a shape of the head portion cannot avoid a lateral impact applied to the electrode terminal (15).

[0132] Compared to a typical electrode terminal (15), the electrode terminal (15) of the embodiment may have a thicker thickness near the center (O). This may seem to reduce the energy density of the battery cell at first glance. However, in a vehicle battery cell requiring high energy density, a first bus bar (81) is joined to the upper portion of the electrode terminal (15). As shown in FIGS. 9 and 10 , if the first bus bar (81) is joined in a manner that does not increase the overall height of the battery cell (91) and the first bus bar (81), there is practically no loss in energy density. That is, as in the embodiment, if the first bus bar (81) has an annular hole, a part of the head portion (61) is accommodated in the hole, and the first bus bar (81) is joined to the surface of the slope section (62) of the electrode terminal (15), the first bus bar (81) does not actually increase the overall height of the battery cell (91).

[0133] In particular, in the case of laminating and joining the first bus bar (81) to the center of the surface of the electrode terminal (15) as in the past, the first bus bar (81) actually increases the total height of the battery cell (91), but the height portion occupied by the first bus bar (81) does not contribute at all to increasing the rigidity of the electrode terminal (15), and rather, considering that the joint portion of the first bus bar (81) and the electrode terminal (15) is easily damaged due to external impact, the joint structure of the electrode terminal (15) and the first bus bar (81) of the embodiment is noteworthy.

[0134] Referring to Fig. 10, the height of a battery pack (90) in which a plurality of battery cells (91) of the embodiment are built in a matrix form inside a pack housing (92) is not increased further compared to the conventional case, even though the height of the electrode terminal (15) is increased.

[0135] The battery pack (90) includes a first bus bar (81) that electrically connects electrode terminals (15) of the plurality of battery cells (91) to each other, and a second bus bar (82) that electrically connects end walls (12) of the plurality of battery cells (91) to each other. The first bus bar (81) is bonded to the surface of the slope section (62) of the electrode terminal (15), and the portion of the first bus bar (81) bonded to the corresponding portion is positioned axially inward from the upper end of the head portion (61) (see FIG. 9).

[0136] Referring to FIGS. 11 and 12 below, the structure of an electrode terminal according to another embodiment of the present invention will be described. To avoid redundant explanation, the description will focus on parts that differ from the previous embodiment.

[0137] The above head portion (61) has a slope section (62) in which the thickness measured in the axial direction gradually increases from the radially outer edge toward the radially inner side. The slope section (62) is provided in a form in which the rate of increase in thickness decreases toward the radially inner side.

[0138] In the embodiment, the bottom surface of the slope section (62) of the head portion (61) is flat, and the surface of the slope section (62) provides an upwardly convex curved surface.

[0139] In the above head section (61), a flat section (63) with a flat surface is provided radially inward from the slope section (62).

[0140] Then, as illustrated, the upper surface of the head portion (61) can form a convex curve at a predetermined section (62) of the edge. According to this head portion shape, even if an object collides with the head portion (61) in a radial direction, the object collides with the curved surface and is deflected, thereby minimizing the impact of the head portion (61) on the object. In addition, even if an object collides with the head portion (61) in an axial direction and applies an external force (F) to the head portion (61), the stress generated in the electrode terminal by the external force is appropriately distributed by the shape of the head portion (61) in the form of a curved surface provided at the edge.

[0141] According to the shape of the head portion (61) above, since the thickness of the central region of the head portion (61) together with the neck portion (64) is the thickest, the phenomenon of the electrode terminal (15) itself being bent downward toward its center (O) can be suppressed.

[0142] Referring to Fig. 12, the slope section (62) is positioned outside the inner surface of the end wall (12) that defines the through hole (121) in the radial direction, including a position (P1).

[0143] Then, since the section of the head portion (61) that overlaps the end wall (12) in the radial direction near the edge gradually becomes thinner as it goes outward in the radial direction, when an external force (F) is applied to the head portion (61) in the axial direction, the stress is evenly distributed in the overlapping section of the head portion (61) and the end wall (12), so that the head portion (61) and the end wall (12) are evenly sagging and deformed. Therefore, it is possible to suppress the displacement of the electrode terminal (15) from being pushed inward in the axial direction from increasing.

[0144] As illustrated in Fig. 12, the ratio of the thickness (T) of the head portion (61) measured at a position corresponding to the edge of the through hole (121) to the length (D) of the head portion (61) extending radially outward more than the through hole (121) may be 0.4 or more and 0.9 or less.

[0145] The battery cell (91) is connected to a first bus bar (81) that electrically connects electrode terminals (15) of a plurality of battery cells (91) to each other, and a second bus bar (82) that electrically connects end walls (12) of a plurality of battery cells (91) to each other. The first bus bar (81) is bonded to the surface of the slope section (62) of the electrode terminal (15), and the portion of the first bus bar (81) bonded to the corresponding portion is positioned axially inward from the upper end of the head portion (61).

[0146] The above first bus bar (81) does not cover the flat section (63) provided radially inward from the slope section (62) of the head portion (61). Then, when an external impact is applied to the electrode terminal (15), the joint portion of the first bus bar (81) and the slope section (62) is protected from the external impact.

[0147] Referring to FIGS. 13 and 14 below, the structure of an electrode terminal of another embodiment according to the present invention will be described with a focus on the parts that are different from the previous embodiments in order to avoid redundant description.

[0148] The above head portion (61) has a slope section (62) in which the thickness measured in the axial direction gradually increases from the radially outer edge toward the radially inner side. The slope section (62) is provided in a form in which the rate of increase in thickness is constant as it goes toward the radially inner side.

[0149] In the embodiment, the bottom surface of the slope section (62) of the head portion (61) is flat, the surface of the slope section (62) provides a sloped surface with a constant incline, and a flat section (63) having a flat surface is provided radially inward from the slope section (62) of the head portion (61). According to this head portion shape, even if an object collides with the head portion (61) in a radial direction, the object collides with the sloped surface and is deflected, thereby minimizing the impact of the head portion (61) on the object. In addition, even if an object collides with the head portion (61) in an axial direction and applies an external force (F) to the head portion (61), the stress generated in the electrode terminal by the external force is appropriately distributed by the shape of the head portion (61) in the form of a sloped surface provided at the edge.

[0150] Referring to Fig. 14, the slope section (62) is positioned outside the neck portion, including a position corresponding to the edge of the neck portion in the radial direction. Then, at least the area of ​​the head portion (61) corresponding to the neck portion (64) in the radial direction is sufficiently thickened in the central portion of the electrode terminal (15) together with the neck portion (64), so that the phenomenon of the electrode terminal (15) itself being bent downward toward its center (O) when subjected to an impact due to an external force (F) can be suppressed.

[0151] As illustrated in Fig. 14, the ratio of the thickness (T) of the head portion (61) measured at a position corresponding to the edge of the through hole (121) to the length (D) of the head portion (61) extending radially outward more than the through hole (121) may be 0.4 or more and 0.9 or less.

[0152] The battery cell (91) is connected to a first bus bar (81) that electrically connects electrode terminals (15) of a plurality of battery cells (91) to each other, and a second bus bar (82) that electrically connects end walls (12) of a plurality of battery cells (91) to each other. The first bus bar (81) is bonded to the surface of the slope section (62) of the electrode terminal (15), and does not cover a flat section (63) provided radially inward from the slope section (62) of the head portion (61).

[0153] According to this structure, the alignment of the intended joining portion of the first bus bar (81) with respect to the electrode terminal (15) can be guided. That is, the virtual center of the joining portion of the first bus bar (81) can be aligned with the center of the electrode terminal (15) by being guided by the slope section (62) of the electrode terminal (15). These functions and operational effects are the same in the embodiments described above.

[0154] Each feature of the embodiments described above may be omitted, replaced, or combined with features of other embodiments, as needed. That is, the number of embodiments that can be implemented by selecting each feature is even greater. However, it should be understood that the foregoing description discloses embodiments sufficient to explain the technical concepts of the present invention.

[0155] 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.

[0156] 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. An electrode assembly comprising a first electrode and a second electrode; A can having a side wall extending axially and surrounding an internal space accommodating the electrode assembly, and an end wall having an edge connected to an axial first end of the side wall and extending radially intersecting the axial direction and electrically connected to the second electrode; A through hole formed in the end wall at a position radially inward from the side wall; An electrode terminal that penetrates the through hole and is installed on the end wall and is electrically connected to the first electrode; and A terminal gasket is interposed between the electrode terminal and the end wall to seal the gap between the electrode terminal and the end wall and electrically insulate the electrode terminal from the end wall; The above electrode terminals: A head portion disposed on the outer side of the above end wall and having a radially outer edge disposed radially outer than the through hole; A neck portion extending axially inward from the head portion and passing through the through hole; and A shoulder portion is disposed on the inner side of the above end wall and extends radially outward from the neck portion; The lower surface of the above head portion presses the terminal gasket together with the outer surface of the end wall, A battery cell, wherein the head portion has a slope section in which the thickness measured in the axial direction gradually increases from the radially outer edge toward the radially inner side.

2. A battery cell according to claim 1, wherein the rate of increase in thickness decreases as it goes radially inward in the slope section.

3. A battery cell according to claim 1, wherein the rate of increase in thickness is constant as one goes radially inward in the slope section.

4. In claim 1, the battery cell is arranged in the entire section of the head portion in the radial direction.

5. A battery cell according to claim 1, wherein a flat section having a flat surface is provided radially inward from the slope section of the head section.

6. In claim 5, the battery cell is arranged outside the inner surface of the end wall defining the through hole in the radial direction, including a position corresponding thereto.

7. In claim 5, the battery cell is arranged outside the edge of the neck portion, including a position corresponding to the edge of the neck portion in the radial direction.

8. In claim 1, a battery cell, wherein a ratio of the thickness of the head portion measured at a position corresponding to the edge of the through hole to a length of the head portion extending radially outwardly more than the through hole is 0.4 or more and 0.9 or less.

9. In claim 1, further comprising a current collector connecting the first electrode of the electrode assembly and the electrode terminal, A battery cell, wherein the central portion of the current collecting plate is joined to the electrode terminal, and the peripheral portion of the current collecting plate surrounding the central portion is joined to the first electrode exposed to the axial first end of the electrode assembly.

10. A battery cell according to claim 1, wherein the shape of the head portion when viewed in the axial direction is circular or polygonal.

11. A battery assembly having a plurality of battery cells according to any one of claims 1 to 8.

12. In claim 11, a bus bar is further included for electrically connecting the electrode terminals of the plurality of battery cells, The above bus bar is a battery assembly connected to the slope section of the above head portion.

13. A battery assembly according to claim 12, wherein the bus bar portion connected to the slope section is positioned axially inward from the upper end of the head portion.

14. A battery assembly according to claim 12, wherein the bus bar does not cover a flat section having a flat surface provided radially inward from the slope section of the head portion.

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