Battery cell and battery pack and vehicle including same

Abstract

A battery cell according to an embodiment of the present invention includes: an electrode assembly in which a first electrode, a second electrode, and a separator therebetween are wound around a winding axis; a can configured to accommodate the electrode assembly through an open end portion formed on one side of the can; a lead covering the open end portion and having a liquid injection hole; and a plug configured to seal the liquid injection hole. The plug may include: a lead coupling portion located on the lead; an insertion portion located radially inward from the lead coupling portion and configured to protrude from the lead coupling portion and be inserted into the liquid injection hole; and an edge portion located at an edge of the lead coupling portion and more recessed downward in the winding axis direction than the lead coupling portion.

Description

Battery cells and battery packs and vehicles containing the same

[0001] The present invention relates to a battery cell, a battery pack including the same, and a vehicle.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0087170, filed on July 2, 2024, and all contents disclosed in the specification and drawings of the said application are incorporated by reference into this application.

[0003] This application claims priority to Korean Patent Application No. 10-2025-0087109, filed on June 30, 2025, and all contents disclosed in the specification and drawings of the said application are incorporated herein by reference.

[0004]

[0005] Cylindrical battery cells house jelly-roll-shaped electrode assemblies within a cylindrical metal can. They are more shock- and temperature-resistant than pouch-type batteries. Consequently, demand for metal can-shaped cells in vehicle battery packs is growing.

[0006] The process of manufacturing a battery cell using a cylindrical can includes deep drawing a metal sheet to form a circular bottom portion and a circular tubular side wall portion connected thereto, accommodating an electrode assembly therein, and then covering the open end of the side wall portion with a lead to finish the process.

[0007] The open end of the battery can is covered with a lead, and the lead and battery can are secured by crimping or seam welding.

[0008] Figure 1 is a drawing showing a method of fixing a lead and a battery can using a conventional crimping method.

[0009] Referring to Fig. 1, crimping is a method of physically pressing the edge of the lead (40) to the open end of the can (10) while interposing a sealing ring (91) to secure the lead (40). Since crimping is a physical fixing method that does not apply heat, it is okay to work while the electrolyte is poured into the can (10). Therefore, the crimping method has the advantage of being able to omit a separate injection port structure and a structure for sealing it. However, crimping is structurally complex compared to welding, and thus has limitations in securing the internal volume of the can (10) that can accommodate the electrode assembly (20).

[0010] In contrast, seam welding involves welding the leading edge of the battery can's sidewall and the edge of the lead along the circumference, thereby simplifying the fixing structure and thus increasing the volume of the electrode assembly that can be accommodated within the battery can. Therefore, seam welding is more advantageous in securing electrical capacity per unit volume of the battery can.

[0011] When fixing the open end of the battery can by deep welding the lead, a method may be applied in which a battery can with a filler port provided at the bottom or a lead with a filler port is prepared, an electrode assembly is accommodated inside the battery can, the battery can and the lead are deep welded, an electrolyte is injected through the filler port, and after the injection is completed, the filler port is sealed.

[0012] However, when welding the filler cap and the lead to seal the filler cap, the beads generated during the welding process may protrude from the surface of the lead or the filler cap. In this case, the contact area between the battery cell leads and the heat sink for bottom cooling of the battery pack may be reduced. In this case, since the cooling performance of the battery pack is proportional to the contact area between the heat sink and the lead, the cooling performance of the battery pack may be reduced.

[0013] Therefore, a sealing structure for the injection port is required that is configured so that beads, etc. do not protrude outside the lead or injection port plug.

[0014]

[0015] The present invention was created in consideration of the above-described problems, and the problem that the present invention seeks to solve is to provide a battery cell with an improved sealing structure of a liquid filler port and a method for manufacturing the same.

[0016] In addition, the present invention seeks to provide a sealing structure of a liquid injection port that maximizes the contact area between a heat sink and a lead of a battery cell in a battery pack including a plurality of battery cells.

[0017] The present invention aims to provide a battery cell including such a sealing structure and a method for manufacturing the battery cell.

[0018] In addition, the present invention aims to provide a battery cell having a high energy density by excluding a beading crimping structure from the battery cell, and a vehicle equipped with a battery pack using the battery cell.

[0019] 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.

[0020]

[0021] According to one embodiment of the present invention for solving the above-described problem, a battery cell includes an electrode assembly in which a first electrode and a second electrode and a separator interposed therebetween are wound around a winding axis, a can configured to receive the electrode assembly through an open end formed at one side thereof, a lead covering the open end and having a liquid inlet formed therein, and a plug configured to seal the liquid inlet, wherein the plug may include a lead engaging portion positioned on the lead, an insertion portion positioned radially inward from the lead engaging portion and configured to protrude from the lead engaging portion and be inserted into the liquid inlet, and an edge portion positioned at an edge of the lead engaging portion and recessed downward in the direction of the winding axis from the lead engaging portion.

[0022] The above edge portion may be formed in a ring shape along the perimeter of the edge portion of the plug.

[0023] The above edge portion may be configured to form the edge portion of the lead joint portion using a forging method.

[0024] The maximum recess depth of the edge portion in the direction of the winding axis may be within a range of 20% to 60% of the thickness of the lead joint portion in the direction of the winding axis.

[0025] The welding bead formed in the process of welding the above plug and the above lead can be configured to settle on the edge portion.

[0026] The maximum recess depth in the winding axis direction of the above edge portion may be longer than the maximum thickness formed along the winding axis direction of the above welding bead.

[0027] The above edge portion may have an edge side surface extending downward from the upper surface of the lead joint portion, and an edge bottom surface extending radially outward from the lower end of the edge side surface.

[0028] The above lead may be provided with a plug coupling portion that surrounds the body portion and the injection port and is recessed downward in the direction of the winding axis relative to the body portion, and is configured to allow the lead coupling portion to be seated therein.

[0029] The height of the upper surface of the lead coupling portion of the plug in the direction of the winding axis may be lower than the height of the upper surface of the body portion of the lead in the direction of the winding axis.

[0030] The lead joint portion of the above plug and the body portion of the above lead may be configured to face each other in the radial direction and be welded.

[0031] The above edge portion may include an edge slope having an angle of inclination that is directed downward and radially outward from the upper surface of the lead joint portion.

[0032] The above insertion part may be configured to be inserted into the injection port in a force-fit manner to primarily seal the injection port.

[0033] The above lead joint portion and the above insert portion may have the same thickness in the direction of the winding axis and may be formed integrally.

[0034] A battery pack according to one embodiment of the present invention for solving the above-described problem may include a battery cell according to one embodiment of the present invention.

[0035] A vehicle according to one embodiment of the present invention for solving the above-described problem may include a battery pack according to one embodiment of the present invention.

[0036]

[0037] According to one aspect of the present invention, a sealing structure of a liquid filler port and a sealing method thereof with improved reliability of the liquid filler port sealing are provided.

[0038] According to one aspect of the present invention, a sealing structure and a sealing method of a liquid injection port capable of maximizing the contact area between a heat sink and a lead and / or plug of a battery cell in a battery pack including a battery cell are provided.

[0039] According to one aspect of the present invention, a sealing structure of a liquid filler hole capable of securing flatness of a battery cell and a sealing method thereof are provided.

[0040] According to one aspect of the present invention, a portion of a plug is inserted into the injection port to secure a temporary sealing force, thereby preventing external leakage of electrolyte vapor, and a portion of the lead and the edge of the plug are thermally bonded to secure a high final sealing force. Since thermal bonding can be performed while preventing external leakage of electrolyte vapor, for example, when laser welding is used as thermal bonding, it is effective in preventing welding defects and ignition.

[0041] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0042]

[0043] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0044] Figure 1 is a drawing showing a method of fixing a lead and a battery can using a conventional crimping method.

[0045] Figure 2 is a perspective view of a battery cell according to one embodiment of the present invention.

[0046] FIG. 3 is a perspective view showing a state before lamination of first electrodes, second electrodes, and separators for manufacturing an electrode assembly to be accommodated in a battery can according to one embodiment of the present invention.

[0047] Fig. 4 is a perspective view of an electrode assembly manufactured by winding the laminate of Fig. 3 into a jelly-roll shape.

[0048] FIG. 5 and FIG. 6 are perspective views showing a state in which a current collector plate is joined to each end of an electrode assembly according to one embodiment of the present invention.

[0049] Figure 7 is a cross-sectional view showing the process of accommodating the electrode assembly in a battery can.

[0050] Figure 8 is a cross-sectional view showing a state in which a can containing an electrode assembly according to one embodiment of the present invention is covered and sealed with a lead.

[0051] Fig. 9 is a cross-sectional view showing a state in which the injection port of a lead is sealed by a plug according to one embodiment of the present invention.

[0052] Fig. 10 is an enlarged cross-sectional view showing the joint portion of the lead and plug of Fig. 9.

[0053] Fig. 11 is a cross-sectional view showing a plug according to one embodiment of the present invention.

[0054] Fig. 12 is a cross-sectional view showing a plug and a lead combined according to one embodiment of the present invention.

[0055] Fig. 13 is a cross-sectional view showing a joint structure of a lead and a plug according to another embodiment of the present invention.

[0056] Fig. 14 is a cross-sectional view showing a joint structure of a lead and a plug according to another embodiment of the present invention.

[0057] Fig. 15 is a cross-sectional view showing the appearance of a lead and a plug after welding according to another embodiment of the present invention.

[0058] Fig. 16 is a cross-sectional view showing a joint structure of a lead and a plug according to another embodiment of the present invention.

[0059] Fig. 17 is a cross-sectional view showing the appearance of a lead and a plug after welding according to another embodiment of the present invention.

[0060] Fig. 18 is a cross-sectional view showing a plug according to another embodiment of the present invention.

[0061] Fig. 19 is a cross-sectional view showing a lead and a plug combined according to another embodiment of the present invention.

[0062] Figure 20 is a flowchart of a method for manufacturing a battery cell to which the liquid cap sealing structure of the present invention is applied.

[0063] FIG. 21 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0064] FIG. 22 is a drawing for explaining a vehicle including the battery pack of FIG. 21.

[0065]

[0066] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0067] The present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and with various modifications. However, these embodiments are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. Therefore, the present invention is not limited to the embodiments disclosed below, but should be understood to include all modifications, equivalents, and substitutes included within the technical spirit and scope of the present invention, as well as substitutions or additions of the components of one embodiment with those of another embodiment.

[0068] Furthermore, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar components will be omitted, and the differences will be described.

[0069] The attached drawings are merely intended to facilitate understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification, but should be understood to encompass all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention. In the drawings, the components may be expressed in exaggerated sizes or thicknesses for ease of understanding, but the scope of protection of the present invention should not be construed as being limited thereby.

[0070] The terminology used in this specification is only used to describe specific implementations or examples and is not intended to limit the present invention. In addition, the singular expression includes the plural expression unless the context clearly indicates otherwise. In the specification, terms such as "comprises" and "consists of" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification. In other words, it should be understood that terms such as "comprises" and "consists of" in the specification do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0071] While terms including ordinal numbers, such as "first" and "second," may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. Therefore, unless otherwise stated, a "first" component may also be a "second" component.

[0072] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0073] 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.

[0074] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0075] When a component is referred to as being “above” or “below” another component, it should be understood that it is not only positioned directly above that other component, but that there may also be other components present in between.

[0076] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0077] Meanwhile, in this specification, terms indicating directions such as up, down, left, right, front, and back may be used, but these terms are only for convenience of explanation, and it is obvious to those skilled in the art that these terms may vary depending on the position, arrangement, rotation, and position of the object being targeted, or the position of the observer.

[0078] 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.

[0079] In describing the embodiment, the winding axis direction refers to the direction in which the axis forming the winding center of the jelly-roll type electrode assembly extends, the radial direction refers to the direction approaching (centripetal) or moving away (centrifugal) from the axis, and the circumferential direction refers to the direction surrounding the axis.

[0080] Fig. 2 is a perspective view of a battery cell according to an embodiment of the present invention. Fig. 3 is a perspective view showing a state before lamination of first electrodes, second electrodes, and separators for manufacturing an electrode assembly to be accommodated in a battery can according to an embodiment of the present invention. Fig. 4 is a perspective view of an electrode assembly manufactured by winding the laminate of Fig. 3 in a jelly-roll shape. Figs. 5 and 6 are perspective views showing a state in which current collectors are respectively bonded to both ends of an electrode assembly according to an embodiment of the present invention. Fig. 7 is a cross-sectional view showing a process of accommodating an electrode assembly in a battery can. Fig. 8 is a cross-sectional view showing a state in which a can accommodating an electrode assembly according to an embodiment of the present invention is covered and sealed with a lid.

[0081] Referring to the following Figures 2 to 8, an embodiment of a battery cell (1) to which the sealing structure of the injection port (42) of the present invention is applied will be described in detail.

[0082] A battery cell (1) can be manufactured by embedding a cylindrical electrode assembly (20) inside a cylindrical battery can (10).

[0083] The battery cell (1) of the embodiment may include an electrode assembly (20), a current collector (31, 32) electrically connected to the electrode assembly (20), and a can (10) that accommodates the electrode assembly (20) and the current collector (31, 32).

[0084] The can (10) may include a side wall portion (11) extending in the direction of the winding axis between the first end and the second end, and a bottom portion (12) connected to the first end of the side wall portion (11) and extending in the radial direction. The second end of the side wall portion (11) in the direction of the winding axis may be open.

[0085] The open end of the above side wall portion (11) can be sealed by covering it with a lid (40) after accommodating the electrode assembly (20) in the can (10).

[0086] The above bottom portion (12) may have a disc shape with a hole formed in the center, and the side wall portion (11) may have a circular tube shape.

[0087] The above-mentioned bottom portion (12) and side wall portion (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 portion (11) with a punch while holding it with a blank holder. Of course, the material of the can (10) is not limited to this.

[0088] A first electrode terminal (13) can be fitted into the hole. The first electrode terminal (13) can be fixed by riveting to the bottom portion (12) with a terminal gasket (14) interposed therebetween. The terminal gasket (14) is interposed between the first electrode terminal (13) and the bottom portion (12), thereby sealing the inside and outside of the can (10) to prevent leakage of the electrolyte and electrically insulating the first electrode terminal (13) and the bottom portion (12).

[0089] However, the method of connecting the first electrode terminal (13) and the bottom part (12) is not limited to this. For example, if the structure can seal between the first electrode terminal (13) and the bottom part (12) and electrically insulate the first electrode terminal (13) and the bottom part (12), various other fixing methods, such as a bolt-nut joint method, a glass seal method, or a chrome coating & PP-MAH thermal bonding method, can also be applied.

[0090] The first electrode terminal (13) above may have a first polarity, and the can (10) may have a second polarity. That is, the bottom (12) of the can (10), the side wall (11) connected thereto, and the lead (40) connected to the side wall (11), which will be described later, may all have a second polarity.

[0091] Accordingly, the battery cell (1) may have both the first electrode terminal (13) and the second electrode terminal (15) positioned at the winding axis end, i.e., the closed end, provided with the bottom portion (12). Then, the battery cell (1) may have both the bus bar connected to the first electrode terminal (13) and the bus bar connected to the second electrode terminal (15) positioned at the upper portion of the battery cell (1).

[0092] In one example, the first electrode terminal (13) may be a positive terminal and the second electrode terminal (15) may be a negative terminal. Of course, the opposite may also be true.

[0093] An electrode assembly (20) is accommodated within the above can (10).

[0094] The electrode assembly (20) may be in the form of a jelly-roll in which the first electrode (21) and the second electrode (22) and the separator (28) interposed therebetween are wound around a winding axis. The outer shape of the electrode assembly (20) along the circumferential direction of the electrode assembly (20) may be circular. However, the structure of the electrode assembly (20) is not limited by the embodiment, and may have a winding structure well known in the art.

[0095] Specifically, the electrode assembly (20) can be manufactured as a cylindrical jelly-roll by preparing a first electrode (21), a second electrode (22), and a separator (28) having a predetermined width and extending a predetermined length along the winding direction as illustrated in FIG. 3, forming a laminated body by sequentially stacking the first electrode (21), the separator (28), the second electrode (22), and the separator (28), and then winding this around a winding axis as illustrated in FIG. 4. The structure of the electrode assembly (20) is not limited by the embodiment, and may have a winding structure well known in the art.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] In the above-mentioned blank portion (26), notches can be formed at a predetermined interval to form flag-shaped notching tabs (27).

[0100] 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.

[0101] 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.

[0102] 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.

[0103] In addition, in the embodiment, a structure is exemplified in which a notching tab (27) is deleted in a predetermined section of the centrifugal end of the non-conductive portion (26) and a predetermined section of the centrifugal end. However, it is of course possible that the notching tab may not be deleted in the centrifugal end of the non-conductive portion, and that the notching tab may not be deleted in the centrifugal end of the non-conductive portion.

[0104] In the jelly-roll type electrode assembly (20), the notched tab (27) can be bent radially and flattened as shown 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.

[0105] 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 (20).

[0106] The notched tabs (27) of the first electrode (21) and the notched tabs (27) of the second electrode (22), which are folded and overlapped in the radial direction, can provide a plane substantially perpendicular to the winding axis direction at both ends of the electrode assembly (20) in the winding axis direction.

[0107] As shown in FIGS. 5 and 6, the first collector plate (31) and the second collector plate (32) can be joined to a substantially flat surface provided by bending the notched tabs (27) exposed at both ends in the winding axis direction of the electrode assembly (20).

[0108] In the embodiment, the first collector plate (31) is exemplified as a positive collector plate and the second collector plate (32) is exemplified as a negative collector plate. The first collector plate (31) may be made of aluminum, and the second collector plate (32) may be made of copper.

[0109] The above-mentioned collector plate (31, 32) can be manufactured by punching, trimming, piercing, and bending a metal sheet.

[0110] Referring to FIG. 5, the first collector plate (31) may include a first terminal connection portion (312) extending radially from the center, a ring portion (313) connecting the centrifugal edge of the first terminal connection portion (312) in a circumferential direction, and a first electrode connection portion (314) extending centripetally from the ring portion (313) but not connected to the first terminal connection portion (312). The center portion of the first terminal connection portion (312) may cover at least a portion of the winding center hole (H) of the electrode assembly (20).

[0111] The first electrode connection portion (314) is joined to the notched tab (27) of the first electrode (21) of the electrode assembly (20) by laser welding or the like before the electrode assembly (20) is placed in the can (10). The welding line of the laser may extend radially.

[0112] Referring to FIG. 6, the second collector plate (32) may include an inner ring (321) that defines a hole (322) corresponding to the winding center hole (H) of the electrode assembly (20) and is provided in a form surrounding the winding center hole (H), a second electrode connection part (323) extending radially from the inner ring (321), and a second terminal connection part (324) that is positioned on the centrifugal side of the second electrode connection part (323) and connected to the inner ring part (321). The second terminal connection part (324) may have an outer ring form that surrounds the edge of the second collector plate (32).

[0113] The second electrode connection portion (323) 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 the electrode assembly (20) is placed in the can (10). The welding line of the laser may extend radially.

[0114] However, the shape and structure of the first collector plate (31) and the second collector plate (32) are not limited to the above-described embodiment and may be designed in various ways. A structure in which the second collector plate (32) is omitted is also possible. In this case, the lead (40) described later serves as the second collector plate.

[0115] As illustrated in Fig. 7, the electrode assembly (20) can be accommodated in the can (10) in a state where the first collector plate (31) is aligned toward the bottom (12) of the can (10). At this time, an insulator (19) may be interposed between the first collector plate (31) and the bottom (12) of the can (10) to electrically insulate the first collector plate (31) from the bottom (12).

[0116] In a state where the electrode assembly (20) is accommodated inside the can (10), the notched tab (27) of the second electrode (22) and the second collector plate (32) can be arranged to face the open end of the side wall portion (11).

[0117] The first terminal connection portion (312) of the first collector plate (31) can be joined to the first electrode terminal (13) fixed to the can (10) by resistance welding, ultrasonic welding, laser welding, or the like. A welding device for welding the first collector plate (31) and the first electrode terminal (13) can approach the back surface of the center of the first terminal connection portion (312) of the first collector plate (31) through the open portion of the can (10), the hole (322) of the second collector plate (32), and the winding center hole (H) of the electrode assembly (20) to perform welding. Of course, the first collector plate (31) and the first electrode terminal (13) can also be joined by brazing or soldering. In other words, various methods can be applied as long as the first collector plate (31) and the first electrode terminal (13) can be electrically connected and fixed to each other. However, the present invention does not exclude a structure in which the positive electrode tab is directly electrically connected to the positive electrode terminal while omitting the positive electrode collector plate.

[0118] With the electrode assembly (20) housed in the can (10), the open end of the can (10) can be sealed and covered with a lid (40) as shown in FIG. 8.

[0119] The can (10) and the lead (40) can be thermally joined. The periphery of the front end of the side wall portion (11) of the battery can (10) and the periphery of the edge of the lead (40) can be brought into contact with each other and welded along the circumference. The contact point of the open end of the can (10) and the lead (40) can be joined. For example, the joining point between the open end of the can (10) and the lead (40) can be joined by welding. For example, the lead (40) can be joined to the can (10) using butt welding. This can be defined as a seam welding method. Since the fixing structure is simple, the volume of the electrode assembly (20) that can be accommodated inside the can (10) can be secured to that extent. Therefore, the seam welding method can be more advantageous in securing electric capacity per unit volume of the can (10).

[0120] Specifically, when it is desired to fix the open end of the can (10) and the lead (40) by deep welding, a method may be applied in which a lead (40) having a liquid injection port (42) is prepared, an electrode assembly (20) is accommodated inside the can (10), the can (10) and the lead (40) are deep welded, an electrolyte is injected through the liquid injection port (42) provided in the lead (40), and after the injection is completed, the liquid injection port (42) is sealed with a plug (50) or the like.

[0121] According to the above-described embodiment of the present invention, the battery cell (1) can have a larger internal capacity with the same external shape than a battery cell (1) formed using a beading and crimping method. Accordingly, the energy density of the battery cell (1) can be increased. However, it should be understood that the can (10) and the lead (40) can be joined by a joining method other than welding, and the joining method is not limited thereto. By joining the can (10) and the lead (40), the battery cell (1) can be guaranteed to be airtight.

[0122] The second terminal connection portion (324) of the second collector plate (32) and the second end of the side wall portion (11) can be joined by a method such as welding. The edges of the can (10) and the lid (40) can also be sealed and joined by a method such as welding. In one example, after the second collector plate (32) and the can (10) are joined, the lid (40) and the can (10) can be joined. In another example, after the second collector plate (32) and the lid (40) are joined, the lid (40) and the can (10) can be joined. In another example, the second collector plate (32), the can (10), and the lid (40) can be welded together.

[0123] The edge of the lead (40) can be electrically connected by being joined to the edge of the open end of the can (10). The inner surface of the can (10) or the lead (40) can be electrically connected to the second collector plate (32). Since the second collector plate (32) is joined to the notched tab (27) of the second electrode (22) of the electrode assembly (20) accommodated inside the can (10) of the battery cell (1), when the lead (40) is electrically connected to the second collector plate (32), the lead (40) can also be electrically connected to the notched tab (27) of the second electrode (22) of the electrode assembly (20). In a structure where the second collector plate (32) is omitted, the shape of the lead (40) can be changed so that the lead (40) can be directly electrically connected to the notched tab (27) of the second electrode (22) of the electrode assembly (20). After the can (10) is sealed with the lead (40), an electrolyte can be injected into the inside of the can (10) through the injection port (42) provided in the lead (40).

[0124] The lead (40) may be composed of a metal material. Therefore, the lead (40) may have conductivity. For example, the lead (40) may include an aluminum material. The lead (40) may be made of, for example, low-carbon steel. The lead (40) may be made of, for example, nickel-plated steel, cold-rolled steel (SPCC or SPCE), or stainless steel (SUS). The lead (40) may be manufactured, for example, by forming a metal plate using a press.

[0125] Fig. 9 is a cross-sectional view showing a state in which the injection port of a lead is sealed by a plug according to one embodiment of the present invention. Fig. 10 is an enlarged cross-sectional view showing a joint portion of the lead and plug of Fig. 9. Fig. 11 is a cross-sectional view showing a plug according to one embodiment of the present invention. Fig. 12 is a cross-sectional view showing a state in which a plug and a lead are combined according to one embodiment of the present invention.

[0126] Referring to FIGS. 9 to 12, a battery cell (1) according to the present invention may include an electrode assembly (20), a can (10), a lead (40) in which a liquid injection port (42) is formed, and a plug (50).

[0127] The lead (40) may have a filler hole (42) formed in at least a portion of the lead (40). The filler hole (42) may be formed in the center of the lead (40). At this time, the filler hole (42) may be blocked by a plug (50) to be described later. For example, the plug (50) may press-fit the filler hole (42). By blocking the filler hole (42) by the plug (50), the sealing of the battery cell (1) may be ensured.

[0128] The injection port (42) can serve as an electrolyte injection port, for example. The center of the injection port (42) can coincide with the center of the winding center hole (H) of the electrode assembly (20). That is, the injection port (42) of the lead (40) can be positioned above the winding center hole (H) of the electrode assembly (20) in the winding axis direction.

[0129] Referring to FIGS. 9 and 10, the plug (50) may be configured to seal the filler port (42). That is, the plug (50) may be configured to be inserted into the filler port (42). At least a portion of the plug (50) may penetrate the filler port (42). By inserting the plug (50) into the filler port (42) of the lid (40), the sealing of the battery cell (1) may be secured. The plug (50) may penetrate the filler port (42) formed in the lid (40) to seal the outside and inside of the can (10), thereby preventing leakage of the electrolyte.

[0130] With this structure, the beading and crimping processes can be omitted, thereby achieving process simplification. Furthermore, the beading and crimping structure can prevent the phenomenon of dead space within the battery increasing in the winding axis direction of the electrode assembly (20), thereby lowering the energy density. In other words, with a structure such as the present invention, the energy density of the battery cell (1) can be improved.

[0131] The lead (40) may have a step formed in the radial direction based on the periphery of the injection port (42). Specifically, the lead (40) may have a body portion (41) and a plug coupling portion (43). The lead (40) may be divided into the body portion (41) and the plug coupling portion (43) based on the step.

[0132] The body portion (41) may be configured to be coupled with the can (10). The edge of the body portion (41) may be in perpendicular contact with the open end of the can (10). The body portion (41) may be welded along the circumferential direction of the portion that contacts the open end of the can (10), which may be defined as a seam weld (as described above).

[0133] The plug joint (43) may be a portion that surrounds the injection port (42) and is recessed downward in the direction of the winding axis from the body portion (41). The plug joint (43) may be located radially inward from the body portion (41). The upper surface of the plug joint (43) may be positioned lower than the upper surface of the body portion (41). That is, a step is formed between the plug joint (43) and the body portion (41), and the step may be a ring shape extending in the circumferential direction with the injection port (42) as the center. The step may be formed by forging.

[0134] The thickness of the plug joint (43) in the winding axis direction may be formed thinner than the thickness of the body part (41) in the winding axis direction. A plug (50) may be mounted on the plug joint (43). A lead joint (51) of the plug (50), which will be described later, may be mounted on the plug joint (43).

[0135] According to the above embodiment of the present invention, a structure in which the lead joint (51) of the plug (50) can be seated can be formed by forging the area around the injection port (42).

[0136] In addition, according to the above-described embodiment of the present invention, the plug coupling portion (43), which is the portion where the plug (50) is coupled, is formed to be recessed in a downward direction toward the electrode assembly (20), so that even when the plug (50) is coupled, the overall height of the battery cell (1) can be maintained constant. That is, when the plug (50) and the lead (40) are coupled, the upper surface of the plug (50) may not protrude upwards relative to the upper surface of the lead (40). In other words, a deviation in the overall height of the battery cell (1) may not occur. Accordingly, the contact portion and / or contact area with a component (e.g., a heat sink) disposed on the upper side of the lead (40) is not limited by the plug (50) and can be maximized. As a result, the cooling performance of the battery cell (1) and / or the battery pack (e.g., the battery pack (P) of FIG. 19) can be increased.

[0137] The plug (50) may be formed with a step in the radial direction. Specifically, the plug (50) may have a lead coupling portion (51), an insertion portion (52), and an edge portion (53).

[0138] The lead coupling portion (51) may be positioned on the lead (40). The lead coupling portion (51) may be mounted on the plug coupling portion (43) of the lead (40). The lead coupling portion (51) may be arranged to overlap the plug coupling portion (43) of the lead (40) in the winding axis direction. In addition, the lead coupling portion (51) may be arranged horizontally with the lead (40). The lead coupling portion (51) may be arranged parallel to the body portion (41) of the lead (40) in the horizontal direction.

[0139] The insertion portion (52) may be located radially inward from the lead coupling portion (51). The insertion portion (52) may be a portion protruding from the lead coupling portion (51) in a direction toward the electrode assembly (20). The insertion portion (52) may be a portion protruding downward from the lead coupling portion (51). The lower surface of the insertion portion (52) may be located lower than the lower surface of the lead coupling portion (51).

[0140] According to one embodiment, with reference to FIG. 10, the upper surface of the plug (50) may be a generally flat surface in the horizontal direction. That is, the upper surface of the insertion portion (52) and the upper surface of the lead coupling portion (51) may be arranged on the same horizontal plane. In this case, the thickness of the insertion portion (52) in the winding axis direction may be formed thicker than the thickness of the lead coupling portion (51) in the winding axis direction. For example, the insertion portion (52) and the lead coupling portion (51) of the plug (50) may be formed and processed by a forging method.

[0141] The insertion portion (52) may be configured to be inserted into the injection port (42). For example, the insertion portion (52) may be inserted into the injection port (42) in a force-fit manner. For example, the outer diameter of the insertion portion (52) may be formed to be substantially the same as or larger than the inner diameter of the injection port (42). Accordingly, the sealing force of the injection port (42) can be adjusted by inserting the insertion portion (52) into the injection port (42). The insertion portion (52) may be inserted into the injection port (42) to primarily seal the injection port (42).

[0142] According to the above-described embodiment of the present invention, the plug (50) has an insertion portion (52), so that it can be pressed into the injection port (42) and maintained in a fixed state even before welding. In addition, it is possible to prevent the plug (50) from being detached from the injection port (42) while being transferred to the welding device. That is, before welding the lead (40) and the plug (50), the insertion portion (52) of the plug (50) can be pressed into the injection port (42) to first secure a temporary sealing force. Therefore, it is possible to prevent a deterioration in welding quality due to the vaporization of the electrolyte. For example, the temporary sealing force secured by pressing the plug (50) is 10 based on the He leak. -5 10 inland -3 It can be atm·cc / s.

[0143] The lead coupling portion (51) of the plug (50) and the body portion (41) of the lead (40) may be configured to face each other in the radial direction and be welded. The outer surface of the lead coupling portion (51) facing outward in the radial direction may face the inner surface of the body portion (41) facing inward in the radial direction. Welding (W) may be performed between the outer surface of the lead coupling portion (51) facing outward in the radial direction and the inner surface of the body portion (41) facing inward in the radial direction. For example, the lead coupling portion (51) may be coupled to the lead (40) using butt welding (W). The welding (W) may be performed at an edge portion of the body portion (41) and / or the lead coupling portion (51). For example, the welding (W) may be performed using a method such as resistance welding, ultrasonic welding, or laser welding.

[0144] According to the above-described embodiment of the present invention, by welding the plug (50) and the lid (40), a final sealing force higher than a temporary sealing force can be secured. Therefore, high airtightness can be secured. In addition, compared to the case where the sealing force is secured only by pressing, the pressing force of the plug (50) can be significantly reduced, and thus, permanent deformation of the lid (40) or the can (10) due to the pressing force can be prevented. For example, the final sealing force that can be secured by welding is approximately 10 based on the He leak. -7 It can be less than atm.cc / s, which means that high confidentiality can be ensured.

[0145] Furthermore, according to the above-described embodiment of the present invention, since welding is performed after securing a temporary sealing force, the phenomenon of electrolyte vapor leaking and ignition occurring during the welding process can be prevented. Therefore, events resulting from thermal runaway in a vehicle containing multiple battery cells, such as fire or explosion, can be prevented or delayed.

[0146] Referring to the portion marked A in FIGS. 10 and 11, the edge portion (53) may be located at the edge of the lead coupling portion (51). The edge portion (53) may refer to a groove or recess structure located at the edge portion of the lead coupling portion (51).

[0147] The edge portion (53) may be a portion of the upper surface of the plug (50) that is recessed downward in the direction of the winding axis compared to other areas. The edge portion (53) may be a portion that is recessed downward in the direction of the winding axis compared to the lead coupling portion (51). For example, the height of the upper surface of the edge portion (53) in the direction of the winding axis may be lower than the height of the upper surface of the lead coupling portion (51) in the direction of the winding axis. That is, a step may be formed at the edge of the upper surface of the lead coupling portion (51).

[0148] For example, the edge portion (53) may be formed by forming the edge portion of the lead joint portion (51) using a forging method. As another example, the edge portion (53) may be formed from the edge portion of the plug (50) using at least one of extrusion, press, and casting methods.

[0149] The edge portion (53) may be formed along the entire circumference of the edge portion of the plug (50) or at least a portion of the circumference. For example, the edge portion (53) may be formed in a ring shape along the circumference of the edge portion of the plug (50). For example, the edge portion (53) may be formed in a plurality of arc shapes along the circumference of the edge portion of the plug (50) and may be formed discontinuously in some areas. In other words, the edge portion (53) may be formed only in the area where welding is performed.

[0150] Referring to Fig. 11, for example, the maximum recess depth (d1) of the edge portion (53) in the winding axis direction can be set within a range of approximately 20% to 60% of the thickness (d2) of the lead coupling portion (51) in the winding axis direction. For example, the maximum recess depth (d1) of the edge portion (53) in the winding axis direction can be set within a range of approximately 30% to 50% of the thickness (d2) of the lead coupling portion (51) in the winding axis direction.

[0151] According to the above embodiment of the present invention, if the maximum recess depth (d1) of the edge portion (53) in the winding axis direction is shorter than 20% of the thickness (d2) of the lead joint portion (51) in the winding axis direction, it is likely to be shorter than the maximum height of the lead joint portion (51). Conversely, if the maximum recess depth (d1) of the edge portion (53) in the winding axis direction is greater than 60% of the thickness (d2) of the lead joint portion (51) in the winding axis direction, there is a concern that the electrolyte may vaporize due to the welding heat, and the vaporized gas of the electrolyte may reach the edge portion (53), which may result in a deterioration in welding performance.

[0152] That is, such a ratio may be set to suppress unnecessary protrusion toward the outer surface of the plug (50) or the lead (40) and maintain the overall cross-sectional shape uniform while ensuring that the welding bead (B) can be stably accommodated within the edge portion (53). However, the above numerical value is only one exemplary range based on a specific embodiment, and in an actual design, the recess depth (d1) may be appropriately modified and adjusted to suit its structural and functional purpose by comprehensively considering various factors such as the applied welding method (e.g., laser, resistance welding, etc.), welding amount, shape and material of the edge portion (53), and assembly tolerance.

[0153] For example, the maximum horizontal length (r1) of the edge portion (53) may be 5% or more and 30% or less of the horizontal separation distance (r2) between the lead coupling portion (51) and the insertion portion (52). For example, the maximum horizontal length (r1) of the edge portion (53) may be 10% or more and 20% or less of the horizontal separation distance (r2) between the lead coupling portion (51) and the insertion portion (52). The horizontal separation distance (r2) between the lead coupling portion (51) and the insertion portion (52) may mean the separation distance between the outer surface of the lead coupling portion (51) and the outer surface of the insertion portion (52).

[0154] According to the above embodiment of the present invention, if the maximum horizontal length (r1) of the edge portion (53) is shorter than 5% of the horizontal separation distance (r2) between the lead joint portion (51) and the insert portion (52), it may be difficult to sufficiently accommodate the welding bead (B). Conversely, if the maximum horizontal length (r1) of the edge portion (53) is greater than 30% of the horizontal separation distance (r2) between the lead joint portion (51) and the insert portion (52), the injection port (42) and the edge portion (53) are not sufficiently spaced apart in the radial direction, so that there is a possibility that the vaporized gas of the electrolyte according to the welding heat may reach the edge portion (53), which may result in a deterioration in welding performance.

[0155] Referring to FIG. 11, the edge portion (53) may have an edge side surface (531) extending downward from the upper surface of the lead coupling portion (51), and an edge bottom surface (532) extending radially outward from the lower end of the edge side surface (531). For example, as shown in FIG. 11, the edge side surface (531) may be a surface extending in a vertical direction parallel to the winding axis. For example, the edge bottom surface (532) may be a surface extending in a horizontal direction perpendicular to the winding axis. For example, the edge side surface (531) and the edge bottom surface (532) may be in vertical contact. However, the shape of the edge portion (53) is not limited by the above embodiment and may be designed in various ways. For example, the edge side surface (531) may be a surface inclined at a predetermined angle (e.g., an acute angle) with respect to the winding axis. For example, the edge bottom surface (532) may be a surface inclined at a predetermined angle (e.g., an acute angle) with respect to the horizontal plane.

[0156] Referring to Fig. 12, the welding bead (B) formed in the process of welding the plug (50) and the lead (40) can be configured to be settled on the edge portion (53). That is, when welding to the lead joint portion (51), the edge portion (53) having a step formed therein can accommodate the welding bead (B). Specifically, the welding bead (B) can be settled within a space surrounded by the edge portion (53) and the inner surface of the body portion (41) of the lead (40).

[0157] The plug (50) and the lead (40) can melt at a certain temperature or higher. The melting point of the plug (50) and / or the lead (40) may be approximately 100 degrees or higher and 1400 degrees or lower. That is, the plug (50) and the lead (40) can be welded and joined by applying heat of 100 degrees or higher and 1400 degrees or lower. At this time, the portion where the plug (50) and the lead (40) are joined by being locally heated by welding to reach the melting point and then solidifying again can be referred to as a weld bead.

[0158] The maximum recess depth (d1) of the edge portion (53) in the winding axis direction may be deeper than the maximum thickness (d3) formed along the winding axis direction of the welding bead (B). That is, the welding bead (B) may not protrude upwards from the upper surface of the plug (50) or the upper surface of the lead (40).

[0159] According to the above-described embodiment of the present invention, there may be no deviation in the total height of the battery cell (1) depending on the presence or absence and / or shape of the welding bead (B). In the case where the welding bead (B) protrudes outward from the plug (50), a large amount of a coating liquid such as thermal grease must be used to form a flat surface. However, according to one embodiment of the present invention, even if the coating liquid is not applied in a large amount, the contact area in contact with the heat sink may be wide.

[0160] According to the above-described embodiment of the present invention, the flatness of the battery cell (1) can be secured. Since the height of the battery cell (1) can be maintained at a constant level, it can be advantageous in terms of battery cell (1) management. In other words, the total height deviation of the battery cell (1) can be prevented. Consequently, the contact portion and / or contact area with a component (e.g., a heat sink) positioned on the upper side of the lead (40) can be maximized without being restricted by the welding bead (B). Consequently, the heat dissipation performance and cooling performance of the battery cell (1) and / or battery pack can be improved.

[0161] Fig. 13 is a cross-sectional view showing a joint structure of a lead and a plug according to another embodiment of the present invention.

[0162] The height of the upper surface of the lead coupling portion (51) of the plug (50) in the direction of the winding axis may be equal to (see Fig. 12) or lower than (see Fig. 13) the height of the upper surface of the body portion (41) of the lead (40) in the direction of the winding axis.

[0163] Referring to Fig. 13, the height of the upper surface of the lead coupling portion (51) of the plug (50) in the winding axis direction may be lower than the height of the upper surface of the body portion (41) of the lead (40) in the winding axis direction. In other words, the thickness (d2) of the lead coupling portion (51) of the plug (50) in the winding axis direction may be smaller than the distance (d4) between the upper surface of the plug coupling portion (43) of the lead (40) and the upper surface of the body portion (41) in the winding axis direction.

[0164] If the height of the plug (50) is higher than the lead (40), there is a problem that the lead (40) is not sufficiently melted by the plug (50) during welding. For example, when laser welding the plug (50) and the lead (40), the laser may be positioned so that the center of the laser is the same as the winding axis. In this case, the laser may be irradiated so that it advances radially outward as it advances downward. In other words, the laser may be irradiated at an angle inclined to the horizontal plane. In this case, if the height of the plug (50) is positioned higher than the lead (40), there is a concern that the welding quality may deteriorate because the laser may not be sufficiently irradiated to the lead (40).

[0165] According to the above-described embodiment of the present invention, the height of the plug (50) in the winding axis direction is formed lower than the height of the leads (40) facing each other in the winding axis direction, so that the laser can be sufficiently irradiated to the leads (40), thereby improving the welding quality.

[0166] Fig. 14 is a cross-sectional view showing the joint structure of a lead and a plug according to another embodiment of the present invention. Fig. 15 is a cross-sectional view showing the appearance of a lead and a plug after welding according to another embodiment of the present invention.

[0167] The above edge portion (53) may have an edge slope (533) having an angle of inclination that faces downward and radially outward from the upper surface of the lead coupling portion (51).

[0168] The edge slope (533) can be formed to extend continuously from the upper surface of the lead joint (51) to the lower surface of the lead joint (51). Accordingly, the maximum recess depth in the winding axis direction of the edge portion (53) can be secured more deeply.

[0169] Referring to FIG. 15, such a configuration can cause the welding bead (B) generated during the welding process between the lead (40) and the plug (50) to be naturally guided downward along the edge slope (533), thereby accumulating or gathering in the lower region of the edge portion (53).

[0170] According to the above-described embodiment of the present invention, a structural free space can be provided that can effectively suppress the phenomenon of the welding bead (B) unnecessarily protruding upward from the upper surface of the lead (40) or plug (50).

[0171] In addition, according to the above-described embodiment of the present invention, the size and shape of the welding bead (B) can be controlled, and the weldable area is expanded in the winding axis direction according to the shape of the edge slope (533), so that the mechanical strength and joint reliability of the lead joint (51) can also be improved.

[0172] Fig. 16 is a cross-sectional view showing the joint structure of a lead and a plug according to another embodiment of the present invention. Fig. 17 is a cross-sectional view showing the appearance of a lead and a plug after welding according to another embodiment of the present invention.

[0173] The above edge portion (53) may have a plurality of edge protrusions (534) protruding outward from the outer surface facing the radial outer side of the lead coupling portion (51).

[0174] A plurality of edge protrusions (453) can be arranged vertically spaced apart. The plurality of edge protrusions (453) are formed to extend from the outer surface of the lead joining portion (51) and can be in contact with the body portion (41) of the lead (40). The plurality of edge protrusions (453) are configured to be in direct contact with the body portion (41) of the lead (40), so that the heat transfer path can be optimized when joining by laser welding. However, the arrangement density and shape of the edge protrusions (453) and the vertical spacing interval can be designed in various ways.

[0175] The edge protrusion (453) may be formed, for example, in a shape having a rectangular cross-section. However, the shape of the edge protrusion (453) is not limited by the above embodiment and may be designed in various ways.

[0176] According to the above-described embodiment of the present invention, a plurality of edge protrusions (453) are partially locally heated and melted as they are sequentially exposed to a laser beam from the upper side to the lower side, and these melted edge protrusions (453) can fall downward and accumulate under the influence of gravity and surface tension. These melted edge protrusions (453) can form a weld bead (B) of a certain shape as they are continuously solidified from the lower side.

[0177] In addition, according to the above-described embodiment of the present invention, a structural free space can be provided that can effectively suppress the phenomenon of the welding bead (B) unnecessarily protruding upward with respect to the upper surface of the lead (40) or plug (50). That is, the space between the lead joint portion (51) and the body portion (41) can be provided as a space capable of accommodating the welding bead (B).

[0178] In addition, according to the above-described embodiment of the present invention, since the edge protrusion (453) itself is melted by welding, the size and shape of the welding bead (B) can be controlled. In addition, since the weldable area is expanded in the winding axis direction, the mechanical strength and joint reliability of the lead joint (51) can also be improved.

[0179] Fig. 18 is a cross-sectional view showing a plug according to another embodiment of the present invention. Fig. 19 is a cross-sectional view showing a lead and a plug combined according to another embodiment of the present invention.

[0180] The configuration of the lead (40) and the plug (50) and the welding (W) process of the lead (40) and the plug (50) are the same as those described with reference to FIGS. 9 to 17, so a repeated description thereof will be omitted.

[0181] The lead coupling portion (51) and the insertion portion (52) of the plug (50) may have substantially the same thickness in the direction of the winding axis. The lead coupling portion (51) and the insertion portion (52) of the plug (50) may be formed integrally. That is, the plug (50) may be bent between the lead coupling portion (51) and the insertion portion (52).

[0182] The plug (50) may be configured to be formed by drawing. The drawing method may refer to a processing method for stretching and thinning metal into a desired shape. The drawing method may be a process of stretching a material such as a metal sheet or wire by pulling it through a mold. For example, a deep drawing process may be a method of forming a plate into a deep container shape using a punch or die. Specifically, the plug (50) may be manufactured by forming and processing using the deep drawing method. Specifically, the plug (50) may be manufactured by fixing an end of a plug preform, which is a plate shape with a certain thickness, and pressurizing the center of the plug preform.

[0183] According to the above-described embodiment of the present invention using a drawing method, the radial distance between the lead joint portion (51) and the insertion portion (52) can be formed relatively long compared to the forging method. Therefore, the vaporized gas of the electrolyte generated by the welding heat can be prevented from directly contacting the lead joint portion (51). In other words, the vaporization path of the electrolyte can be further extended. Therefore, welding defects caused by the vaporization heat of the electrolyte can be prevented.

[0184] According to the above-described embodiment of the present invention, the plug (50) is manufactured by drawing, thereby reducing the weight of the plug (50), which can contribute to reducing the weight of the battery cell (10). In addition, the manufacturing cost of the plug (50) is reduced, and the processing method of the plug (50) is simple and easy, so that the manufacturing time can be shortened.

[0185] Figure 20 is a flowchart illustrating a method for manufacturing a battery cell to which the liquid cap sealing structure of the present invention is applied. Hereinafter, a method for manufacturing a battery cell according to an embodiment of the present invention will be described with reference to Figure 20. For convenience of explanation, the description may be made with reference to the drawings of Figures 1 to 19.

[0186] First, an electrode assembly (20) can be prepared (S1) including a can (10) in which a first electrode terminal (13) is fixed in an insulating seal on a bottom portion (12), and a first collector plate (31) and a second collector plate (32) welded to the first electrode and the second electrode at both ends, respectively.

[0187] Next, a step of covering the open end with the lead (40) while the electrode assembly (20) is accommodated in the can (10) may be included (S2).

[0188] The electrode assembly (20) can be accommodated in the can (10) in a state where the first collector plate (31) is aligned so as to face the bottom (12) of the can (10). At this time, an insulator (19) can be interposed between the first collector plate (31) and the bottom (12) of the can (10) to electrically insulate the first collector plate (31) from the bottom (12).

[0189] A step of bonding the edge of the lead (40) to the can (10) may be included (S3). The lead (40) and the can (10) may be thermally bonded.

[0190] The periphery of the front end of the side wall portion (11) of the battery can (10) and the periphery of the edge of the lead (40) can be brought into contact with each other and welded along the circumferential direction. The contact point between the open end of the can (10) and the lead (40) can be joined. For example, the joining point between the open end of the can (10) and the lead (40) can be joined by welding. For example, the lead (40) can be joined to the can (10) using butt welding. This can be defined as a seam welding method.

[0191] In addition, before joining the edge of the lead (40) to the can (10), the first collector plate (31) can be thermally joined to the first electrode terminal (13). In addition, the open end of the can (10) can be sealed by covering it with the lead (40), and the second collector plate (32) can be electrically connected to the can (10) and the lead (40), which are the second electrode terminals (15), by joining the second collector plate (32) to the can (10) and / or the lead (40), and thermally joining the lead (40) and the can (10).

[0192] Next, a step of injecting an electrolyte into the battery can (10) through the injection port (42) of the lead (40) may be included (S4).

[0193] Next, a step of inserting a plug (50) into the injection port (42) after the electrolyte injection may be included (S5). The insertion portion (52) of the plug (50) may be configured to be inserted into the injection port (42). For example, the insertion portion (52) may be inserted into the injection port (42) in a force-fit manner. The insertion portion (52) may be fitted into the injection port (42) to primarily seal the injection port (42).

[0194] According to the above-described embodiment of the present invention, the plug (50) has an insertion portion (52), so that it can be pressed into the injection port (42) and maintained in a fixed state even before welding. In addition, the plug (50) can be prevented from being detached from the injection port (42) while being transported to the welding device. That is, before welding the lead (40) and the plug (50), a temporary sealing force can be secured first by pressing the insertion portion (52) of the plug (50) into the injection port (42).

[0195] Finally, a step of welding the plug (50) and the lead (40) may be included (S6).

[0196] The above sealing finish can be achieved by first securing a temporary sealing force by pressing the plug (50) into the injection port (42), and then sealing the lead joint (51) of the plug (50) and the lead (40) by welding them together to secure the final sealing force.

[0197] For example, the lead joint (51) of the plug (50) and the body (41) of the lead (40) can be laser welded. Laser welding can be defined as a process of melting and joining metal using a laser beam with high energy density.

[0198] According to the above-described embodiment of the present invention, since welding is performed after securing temporary sealing force, the phenomenon of gas channels being formed or cracks occurring during the welding process can be prevented, thereby preventing defects in the lead joint (51).

[0199] In addition, according to the above-described embodiment of the present invention, since welding is performed after securing temporary sealing force, the phenomenon of electrolyte vapor leaking to the outside and ignition during the welding process can be prevented.

[0200] Fig. 21 is a drawing for explaining a battery pack according to one embodiment of the present invention. Fig. 22 is a drawing for explaining a vehicle including the battery pack of Fig. 21.

[0201] Referring to FIG. 21, a battery pack (P) according to the present invention may include at least one battery cell (1) according to the present invention described above. In addition, the battery pack (P) according to the present invention may include a pack housing (2) capable of accommodating the at least one battery cell (1). The battery pack (P) may be configured using a battery module, which is an intermediate form of assembly, or may be configured directly without a battery module, as illustrated. Since the battery cell (1) itself has a large volume, there may be no particular difficulty in implementing the battery pack (P) even without using an intermediate structure called a battery module.

[0202] In addition, the battery pack (P) may further include various other components in addition to the battery cells (1), such as components of the battery pack (P) known at the time of application of the present invention, such as a BMS, a relay, a current sensor, etc.

[0203] A battery pack (P) may include a plurality of battery cells (1). The battery cells (1) may be arranged in a predetermined number of rows, and may be arranged such that the first electrode terminal (13) and the second electrode terminal (15) of each battery cell (1) are both positioned on the upper side. Therefore, when electrically connecting the plurality of battery cells (1), both the positive and negative electrodes can be connected in one direction, thereby simplifying the electrical connection structure. This increases the number of battery cells (1) that can be mounted in the same space, thereby improving energy density and facilitating electrical wiring work. Therefore, the space efficiency is good, and the electrical wiring efficiency is high, which significantly improves workability during the assembly process of the electric vehicle, as well as during the assembly and maintenance of the battery pack (P). In addition, as described above, each battery cell (1) may have a higher energy density than before. A battery pack (P) with such a high energy density can store the same amount of energy while reducing its volume and weight.

[0204] Therefore, if a battery pack (P) to which such a battery cell (1) is applied is mounted on a vehicle such as an automobile (M) that uses electricity as an energy source as shown in Fig. 18, the mileage of the vehicle can be further increased in proportion to the energy consumed.

[0205] In addition, the battery pack (P) may further include a heat sink. The pack housing (2) may accommodate the heat sink. The heat sink may be disposed, for example, at the bottom of the battery cell (1). In this case, the heat sink may be in contact with a lead (e.g., a lead (40) in FIG. 12) and / or a plug (e.g., a plug (50) in FIG. 12) of the battery cell (1). According to the above-described exemplary configuration of the present invention, the upper surface of the plug (50) may not protrude upwardly relative to the upper surface of the lead (40). In addition, the weld bead (e.g., a weld bead (B) in FIG. 12) may not protrude upwardly relative to the upper surface of the lead (40). That is, since no deviation in the total height of the battery cell (1) occurs, the contact portion and / or contact area between the lead (40) and the heat sink is not limited by the plug (50) and / or the weld bead (B), and may be maximized. As a result, the cooling performance of the battery cell (1) and / or battery pack (P) can be increased.

[0206] Referring to FIG. 22, a vehicle (M) according to the present invention may include at least one battery pack (P) according to the present invention.

[0207] The battery cell (1) according to the present invention can be applied to automobiles such as electric vehicles or hybrid vehicles. That is, the automobile (M) according to the present invention can include the battery cell (1) according to the present invention or the battery pack (P) according to the present invention. In addition, the automobile (M) according to the present invention can further include various other components included in the automobile in addition to the battery cell (1) or the battery pack (P). For example, the automobile (M) according to the present invention can further include a body, a motor, a control device such as an ECU (electronic control unit), etc. in addition to the battery cell (1) according to the present invention. The automobile (M) includes a four-wheeled automobile and a two-wheeled automobile. The automobile (M) can operate by receiving power from the battery pack (P) according to one embodiment of the present invention.

[0208] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis; A can configured to receive the electrode assembly through an open end formed on one side; A lead covering the above open end and having a liquid hole formed therein; and A plug configured to seal the above-mentioned injection port; A battery cell comprising: a lead coupling portion positioned on the lead; an insertion portion positioned radially inward from the lead coupling portion and configured to protrude from the lead coupling portion and be inserted into the injection port; and an edge portion positioned at an edge of the lead coupling portion and recessed downward in the winding axis direction from the lead coupling portion.

2. In paragraph 1, A battery cell characterized in that the edge portion is formed in a ring shape along the perimeter of the edge portion of the plug.

3. In paragraph 1, A battery cell characterized in that the edge portion is configured to form the edge portion of the lead joint portion using a forging method.

4. In paragraph 1, A battery cell characterized in that the maximum recess depth of the edge portion in the winding axis direction is within a range of 20% to 60% of the thickness of the lead joint portion in the winding axis direction.

5. In paragraph 1, A battery cell characterized in that the welding bead formed in the process of welding the plug and the lead is configured to settle on the edge portion.

6. In paragraph 5, A battery cell characterized in that the maximum recess depth of the edge portion in the winding axis direction is deeper than the maximum thickness formed along the winding axis direction of the welding bead.

7. In paragraph 6, A battery cell characterized in that the edge portion has an edge side surface extending downward from the upper surface of the lead joint portion, and an edge bottom surface extending radially outward from the lower end of the edge side surface.

8. In paragraph 1, A battery cell characterized in that the lead comprises a body portion; and a plug coupling portion that surrounds the injection port and is recessed downward in the direction of the winding axis from the body portion, and is configured so that the lead coupling portion is seated.

9. In paragraph 8, A battery cell characterized in that the height of the upper surface of the lead coupling portion of the plug in the direction of the winding axis is lower than the height of the upper surface of the body portion of the lead in the direction of the winding axis.

10. In paragraph 8, A battery cell characterized in that the lead joint portion of the plug and the body portion of the lead are configured to face each other in the radial direction and be welded.

11. In paragraph 1, A battery cell characterized in that the edge portion includes an edge slope having an angle of inclination that is directed downward and radially outward from the upper surface of the lead joint portion.

12. In paragraph 1, A battery cell characterized in that the insertion part is configured to be inserted into the injection port in a force-fit manner to primarily seal the injection port.

13. In paragraph 1, A battery cell characterized in that the lead joint portion and the insert portion have the same thickness in the direction of the winding axis and are formed integrally.

14. A battery pack comprising at least one battery cell as described in any one of claims 1 to 13.

15. A vehicle characterized by comprising at least one battery cell as described in any one of claims 1 to 13.

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