Battery cell and battery pack and vehicle including same

Abstract

A battery cell according to one embodiment of the present invention comprises: 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 open end and having an injection hole formed therein; and a plug configured to seal the injection hole, wherein the plug includes an insertion portion configured to be inserted into the injection hole, and a lead coupling portion extending upward in the winding axis direction from the insertion portion and seated on the lead, and the diameter of the insertion portion may be larger than the inner diameter of the injection hole.

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. 10-2024-0101084, filed on July 30, 2024, and all contents disclosed in the specification and drawings of the said application are incorporated by reference into this application.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] Figure 1 is a drawing showing a method of fixing a lead and a battery can using a conventional crimping method.

[0007] 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 has limitations in securing the internal volume of the can (10') that can accommodate the electrode assembly (20').

[0008] 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.

[0009] For example, a sealing member, such as a metal ball, can be forcibly inserted into the injection port to seal and secure the injection port. This method involves forcibly inserting a metal ball with a diameter larger than the inner surface of the injection port into the injection port, so that the surfaces of the inner surface of the injection port and the metal ball are compressed together through elastic deformation, thereby forming a seal.

[0010] There have been cases where aluminum balls have been used as metal balls to seal the filler port. Because aluminum balls are capable of low-temperature plastic deformation, forcibly inserting a slightly larger aluminum ball into the filler port deforms the aluminum and seals the port. However, if the lead itself, where the filler port is formed, is the negative electrode of the battery electrode, aluminum balls cannot be used.

[0011] Meanwhile, if a steel ball is used instead of aluminum, a seal must be established between the rigid lead and the rigid ball. However, during the process of forcibly inserting the steel ball into the lead's inlet port, scratches parallel to the inlet direction occur on the inner surface of the inlet port and the surface of the steel ball. These scratches can cause problems, acting as channels through which gas within the battery cell can leak.

[0012] However, if the ball is pressed in with very strong force to eliminate even these channels, the lead itself will be deformed in the direction of pressing due to the force, which will not only cause a poor appearance of the lead, but there is also a risk that the deformed lead will come into contact with the electrode assembly inside the can, causing a short circuit.

[0013] Additionally, blind riveting can be used to physically seal the injection port. This method also requires a seal between the rigid rivet and the rigid lead. However, this method also causes scratches during the riveting process, leading to the same problem as described above.

[0014] Accordingly, coating the surface of the ball with a polymer material (rubber, plastic) with high chemical resistance and mechanical strength could be considered. However, this material is expensive, and there are concerns that the polymer material may deteriorate due to repeated temperature shocks between high and low temperatures. This also raises the risk of gas leakage.

[0015] Meanwhile, to reduce the possibility of gas leakage between the rigid lid and the rigid filler cap, a method of covering the filler cap with a steel cap and then welding and sealing the gap between the cap and the filler cap can be considered. However, even with this method, the heat generated when welding the cap to the lid can cause the electrolyte inside the can to vaporize and release gas. This can lead to cracks or gas channels forming at the lid joint along the gas release path, which can lead to electrolyte leakage or a fire hazard due to the high temperature, gas, and oxygen.

[0016] Therefore, a sealing structure for a liquid injection port is required that has improved sealing performance without electrolyte leakage, gas leakage due to electrolyte vaporization, and weld defects or the possibility of ignition.

[0017]

[0018] The present invention was created in consideration of the above-described problems, and aims to provide a sealing structure for a liquid injection port and a sealing method thereof, which are free from defects in the welded portion or the possibility of ignition due to electrolyte gas even when welding is applied to seal the liquid injection port.

[0019] In addition, the present invention aims to provide a battery cell including such a sealing structure.

[0020] In addition, another object of the present invention is to provide a method for manufacturing a battery cell using such a sealing method.

[0021] 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.

[0022] 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.

[0023]

[0024] 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 includes an insertion portion configured to be inserted into the liquid inlet, and a lead coupling portion extending upward in the direction of the winding axis from the insertion portion and seated on the lead, and a diameter of the insertion portion may be larger than an inner diameter of the liquid inlet.

[0025] The tolerance between the diameter of the above insertion portion and the inner diameter of the injection port may be 50 μm or more and 150 μm or less.

[0026] The diameter of the above lead joint may be larger than the diameter of the above insertion part.

[0027] The diameter of the above lead joint may be 1.1 to 1.5 times larger than the diameter of the above insertion portion.

[0028] The side of the above insertion portion and the side of the above lead joint portion may be spaced apart from each other in the horizontal direction.

[0029] The side of the above insert may be a sloped surface inclined at a specified angle.

[0030] The diameter of the lower surface of the insertion portion may be formed smaller than the diameter of the upper surface of the insertion portion, and the inner diameter of the injection port may be larger than the diameter of the lower surface of the insertion portion and smaller than the diameter of the upper surface of the insertion portion.

[0031] The above lead may have 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 to secure the lead coupling portion.

[0032] The lead joint portion of the plug and the body portion of the lead may be configured to face each other in the radial direction and be welded.

[0033] The above can and lid may be heat bonded.

[0034] A method for manufacturing a battery cell according to one embodiment of the present invention may include the steps of: covering an open end of a can with a lead while accommodating an electrode assembly in the can; thermally bonding an edge of the lead to the can; injecting an electrolyte into the can through a filler port of the lead; sealing the filler port by inserting an insertion portion of a plug into the filler port; and welding the lead to a lead coupling portion that extends upward in the direction of a winding axis from the insertion portion of the plug and is seated on the lead.

[0035] 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.

[0036] 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.

[0037]

[0038] According to one aspect of the present invention, a sealing structure of a liquid filler port and a sealing method thereof are provided, in which even when welding is applied for sealing a liquid filler port, there is no possibility of defects or ignition at the welded portion due to electrolyte gas, and the reliability of the liquid filler port sealing is improved.

[0039] According to one aspect of the present invention, by configuring the injection port to insert only a plug, which is a single unit component, the internal space of the cell can be relatively widened and the width of the injection port can be formed wide, thereby improving the injection efficiency.

[0040] According to one aspect of the present invention, a temporary sealing force is secured by press-fitting the insertion portion of the plug to prevent external leakage of electrolyte vapor, and a high final sealing force is secured by thermally bonding a portion of the lead and the edge of the lead-joining portion of the plug. Since thermal bonding can be performed while preventing external leakage of electrolyte vapor, for example, when laser welding is used as thermal bonding, there is an effect of preventing welding defects and ignition.

[0041] According to one aspect of the present invention, a liquid injection port can be sealed using two processes: press-fitting and thermal bonding, using a single unit component. This reduces the number of components and assembly work.

[0042] 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.

[0043]

[0044] 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.

[0045] Figure 1 is a drawing showing a method of fixing a lead and a battery can using a conventional crimping method.

[0046] Figure 2 is a perspective view of a battery cell according to one embodiment of the present invention.

[0047] 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.

[0048] Fig. 4 is a perspective view of an electrode assembly manufactured by winding the laminate of Fig. 3 into a jelly-roll shape.

[0049] 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.

[0050] FIG. 7 is a cross-sectional view showing a process of accommodating an electrode assembly in a battery can according to one embodiment of the present invention.

[0051] 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.

[0052] 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.

[0053] Fig. 10 is a cross-sectional view showing a plug according to one embodiment of the present invention.

[0054] Fig. 11 is a cross-sectional view showing a plug inserted into a lead according to one embodiment of the present invention.

[0055] Fig. 12 is a cross-sectional view showing a plug and a lead combined according to one embodiment of the present invention.

[0056] Fig. 13 is a cross-sectional view showing a plug inserted into a lead according to another embodiment of the present invention.

[0057] Fig. 14 is a cross-sectional view showing a plug and a lead combined according to another embodiment of the present invention.

[0058] Fig. 15 is a cross-sectional view showing a lead and a plug combined according to another embodiment of the present invention.

[0059] Fig. 16 is a cross-sectional view showing a plug according to another embodiment of the present invention.

[0060] Fig. 17 is a cross-sectional view showing a lead and a plug combined according to another embodiment of the present invention.

[0061] Figure 18 is a flowchart of a method for manufacturing a battery cell to which the liquid cap sealing structure of the present invention is applied.

[0062] FIG. 19 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0063] FIG. 20 is a drawing for explaining a vehicle including the battery pack of FIG. 19.

[0064]

[0065] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] The present invention may be implemented independently of the following embodiments. Furthermore, the present invention may be implemented by combining two or more of the following embodiments. Each of the following embodiments may be implemented independently and may also be freely combined with one another.

[0079] For convenience of explanation, in this specification, the direction along the longitudinal direction of the winding axis of the electrode assembly wound in a jelly-roll shape is referred to as the winding axis direction. In addition, the direction surrounding the winding axis of the electrode assembly is referred to as the circumferential direction, and the direction in which the electrode assembly is wound along the winding axis is referred to as the winding direction. In addition, the direction moving away from or toward the winding axis of the electrode assembly is referred to as the radial direction.

[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. FIG. 5 and FIG. 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 according to an embodiment of the present invention. 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 this structure, by excluding the beading crimping structure from the battery cell (1), the occurrence of various process errors that may occur due to the beading crimping structure can be prevented. In addition, process simplification can be achieved by omitting the beading and crimping processes. Furthermore, the formation of the beading crimping structure can prevent the phenomenon of the dead space within the battery increasing in the winding axis direction of the electrode assembly (20) and the energy density decreasing. Therefore, the battery cell (1) according to the present invention can increase the internal capacity more than the battery cell using the beading and crimping methods with the same external shape. That is, according to a structure like the present invention, the energy density of the battery cell (1) can be improved.

[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). However, in a structure where the second collector plate (32) is omitted, the shape of the lead (40) may 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). That is, the lead (40) according to the present invention may be provided as a so-called integrated lead (40) that can also perform the function of the collector plate. Therefore, the internal capacity can be increased more than that of a battery cell (1) with the same external shape as that of the current collector plate. Therefore, the energy density of the battery cell (1) can be increased.

[0124] After sealing the can (10) with the lid (40), the electrolyte can be injected into the inside of the can (10) through the injection port (42) provided in the lid (40).

[0125] The lead (40) may be made 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, a low-carbon steel material. The lead (40) may be made of, for example, a nickel-plated steel plate (Ni-plated steel), a cold-rolled steel plate (SPCC or SPCE), or a stainless steel (SUS) material. The lead (40) may be manufactured by, for example, forming a metal plate by pressing. The lead (40) may be formed to have a thickness of, for example, 0.1 mm or more and 2.0 mm or less. The lead (40) may be formed to have a thickness of, for example, 0.3 mm or more and 1.0 mm or less.

[0126] 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 a cross-sectional view showing a plug according to one embodiment of the present invention. Fig. 11 is a cross-sectional view showing a state in which a plug according to one embodiment of the present invention is inserted into a lead. 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.

[0127] 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).

[0128] 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). 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.

[0129] 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.

[0130] 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) and be thermally bonded (welded) to the lid (40). Accordingly, the exterior and interior of the can (10) may be sealed, and leakage of the electrolyte may be prevented.

[0131] 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.

[0132] The plug (50) may be configured to cover the injection port (42). The plug (50) may mean, for example, a sealing member, a stopper, etc. that covers the injection port (42). The plug (50) may be characterized by including at least one of low-carbon steel and copper (Cu).

[0133] At least a portion of the plug (50) can be pressed into the interior of the injection port (42). For example, the pressing load of the plug (50) can be approximately 150 kgf or less.

[0134] The above plug (50) may include an insertion portion (51) and a lead coupling portion (52). The insertion portion (51) and the lead coupling portion (52) may have a columnar shape with different diameters. The plug (50) may have a step formed in the radial direction.

[0135] The insertion portion (51) can be configured to be inserted into the injection port (42).

[0136] Referring to FIGS. 10 and 11, the diameter (D1) of the insertion portion (51) may be larger than the inner diameter (R1) of the injection port (42) (D1>R1). For example, the overlap dimension or tolerance (t) between the diameter (D1) of the insertion portion (51) and the inner diameter (R1) of the injection port (42) may be 20 μm or more and 300 μm or less. For example, the overlap dimension or tolerance (t) between the diameter (D1) of the insertion portion (51) and the inner diameter (R1) of the injection port (42) may be 50 μm or more and 150 μm or less. For example, the tolerance (t) between the plug (50) and the injection port (42) may be approximately 70 μm or more and 150 μm or less in the radial direction. Here, the overlap dimension or tolerance (t) between the diameter (D1) of the insertion portion (51) and the inner diameter (R1) of the injection port (42) may refer to the gap between the outer surface of the insertion portion (51) formed on one side centered on the injection port (42) and the inner surface of the lead (40). That is, the insertion portion (51) can be forcibly fitted into the injection port (42).

[0137] According to an embodiment of the present invention, the diameter (D1) of the insertion portion (51) of the plug (50) is formed to be larger than the inner diameter (R1) of the injection port (42), so that the insertion portion (51) can be forcibly inserted into the injection port (42) using physical force, and the electrolyte formed inside can be prevented from flowing out of the injection port (42).

[0138] In addition, according to the above embodiment of the present invention, the temporary sealing force can be first secured by pressing the insertion part (51) of the plug (50) into the injection port (42) before the thermal bonding to a degree that the sealing force can be secured against the pressure of the vaporized gas of the electrolyte generated by the welding heat generated when the lead (40) and the lead joint (52) are thermally bonded. Therefore, the deterioration of the welding quality due to the vaporization of the electrolyte can be prevented. 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. Here, the He leak test refers to a test that quantitatively evaluates the presence of micro-leakage in a target component using helium gas (He) as a tracer gas for leak detection. This temporary sealing force is sufficient to suppress vapor emissions, thereby preventing weld defects and the risk of electrolyte ignition during subsequent welding. In other words, high airtightness can be secured.

[0139] Specifically, the welding heat generated during the process of joining the lead (40) and the lead joint (52) by a thermal joining method such as laser welding can increase the partial pressure of the flammable electrolyte vapor, which has a relatively low boiling point of about 90°C, thereby causing the vapor to be released to the outside. If the vapor thus released comes into contact with the high-temperature plug (50) or lead (40), the risk of ignition or explosion may increase, or welding defects (e.g., pores, incomplete joining) may occur.

[0140] However, according to the present invention, by sealing the plug (50) by a forced-fit method, the leakage of such vapor is blocked, and as a result, contact between the vapor and the high-temperature plug (50) or lead (40), which is a molten material, during welding can be prevented. Accordingly, the stability and reliability of the laser welding process are improved, and deterioration of welding quality or ignition accidents, etc., can be prevented.

[0141] In addition, according to the above-described embodiment of the present invention, since the temporary sealing force is lower than the final sealing force, the press-fitting load of the plug (50) can be reduced compared to a case where the sealing force is secured through press-fitting alone. Accordingly, local plastic deformation or structural damage that may occur in the lid (40) or can (10) due to excessive press-fitting force can be effectively prevented.

[0142] The lead coupling portion (52) can be formed to extend upward in the direction of the winding axis from the insertion portion (51). The lead coupling portion (52) can be mounted on the lead (40).

[0143] The diameter (D2) of the lead coupling portion (52) may be larger than the diameter (D1) of the insertion portion (51) (D2>D1). For example, the diameter (D2) of the lead coupling portion (52) may be approximately 1.1 to 1.5 times larger than the diameter (D1) of the insertion portion (51). For example, the diameter (D2) of the lead coupling portion (52) may be approximately 1.2 times larger than the diameter (D1) of the insertion portion (51).

[0144] The side surface of the above insertion portion (51) and the side surface of the lead coupling portion (52) can be horizontally spaced apart from each other. The edge portion of the lead coupling portion (52) and the edge portion of the insertion portion (51) can be horizontally spaced apart from each other.

[0145] Referring to Fig. 10, the lower edge of the lead joint (52) may be subjected to a rounding process (r). This rounding process (r) minimizes any step or interference when in contact with the lead (40), thereby enabling precise and stable joining without overlapping with the lead (40). This not only improves the ease of the assembly process, but also alleviates mechanical stress concentration. Meanwhile, the shape of the lead joint (52) is not limited to the above-described embodiment and may be designed in various ways. In addition, other corner portions may also be subjected to the same rounding process (r). This can further improve the overall assembly and durability of the component.

[0146] In general, when the relative distance between the insertion portion (51) and the lead joint portion (52) is close, the electrolyte vapor or residual vapor generated after the electrolyte injection may be re-vaporized by heat during welding and may flow into the welding area of ​​the lead joint portion (52). Such vapor mixing may result in a decrease in welding strength, the generation of porosity, or the risk of ignition during the laser welding process.

[0147] According to the above-described embodiment of the present invention, by designing the distance between the insertion portion (51) and the lead joint portion (52) to be a certain distance or more, a structure can be provided that makes it difficult for electrolyte vapor to reach the welding area. Accordingly, welding defects can be prevented and the risk of ignition due to electrolyte leakage can be prevented.

[0148] The lead (40) and the lead joint (52) of the plug (50) may be configured to be thermally joined. The thermal joining of the lead (40) and the lead joint (52) may be performed by any one of welding (W), brazing, and soldering. That is, the edge portion of the lead joint (52) may be configured to be spatially spaced apart from the edge portion of the insertion portion (51) in the horizontal direction by a specified distance. At this time, for example, the melting point of the lead joint (52) may be approximately 100 degrees or more and 1400 degrees or less. That is, welding (W) may be performed between the lead joint (52) and the lead (40) by applying heat of 100 degrees or more and 1400 degrees or less.

[0149] According to the above-described embodiment of the present invention, the welding portion of the lead joint (52) can be formed to be spaced apart from the injection port (42) (or insertion portion (51)), so that the electrolyte does not flow out to the welding portion.

[0150] The thermal joint between the lead (40) and the lead joint (52) of the plug (50) may have a smaller area to be welded compared to the deep welding. For example, in the case of a 4680 battery cell, the diameter of the lead (40) where the deep welding is performed is approximately 46 mm, and the diameter (D2) of the lead joint (52) of the plug (50) where the thermal joint between the lead (40) and the lead joint (52) is performed may be approximately 10 mm or more and 15 mm or less. Since thermal deformation occurs due to heat accumulation during welding in a narrow area, tack welding may be necessary. In addition, the temperature around the injection port (42) may be high due to welding defects and heat concentration caused by the generation of vaporized gas in the electrolyte, which may also cause ignition issues. However, according to the above-described embodiment of the present invention, the diameter (D2) of the lead joint (52) is formed to be larger than the diameter (D1) of the insertion portion (51), so that thermal deformation during welding is reduced, and the problems of welding defects and ignition can be solved.

[0151] That is, the sealing finish of the lead (40) and the plug (50) 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 (52) of the plug (50) and the lead (40) by welding (W) to secure the final sealing force.

[0152] The ultimate sealing strength can be greater than the temporary sealing strength. For example, the ultimate sealing strength that can be achieved by welding is approximately 10 times the He leak rate. -7 It can be less than atm.cc / s, which means that high confidentiality can be ensured.

[0153] 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 (52).

[0154] Furthermore, according to the above-described embodiment of the present invention, since welding (W) is performed after securing a temporary sealing force, the phenomenon of electrolyte vapor leaking to the outside and ignition during the welding process can be prevented. Accordingly, events resulting from thermal runaway in a vehicle containing a large number of battery cells, such as fire or explosion, can be prevented or delayed.

[0155] Furthermore, the insertion portion (51) configured to secure temporary sealing force and the lead joint portion (52) configured to be thermally bonded are spaced apart in the axial direction to prevent the electrolyte vapor from directly contacting the welding area.

[0156] As a comparative example, consider a method that involves inserting a plastic ball after electrolyte injection, then inserting a separate plug to complete the welding process. This method requires two separate components: the plastic ball and the plug. The number of steps involved is three: inserting the plastic ball, inserting the plug, and welding.

[0157] Compared to the comparative example, according to the embodiment of the present invention, only one plug (50) component can be included without additional configuration. That is, the insertion portion (51) of the plug (50) can be configured to be press-fitted into the injection port (42), and further, the lead joint portion (52) of the plug (50) can be configured to be welded to the lead (40). Accordingly, compared to the comparative example, the number of components can be reduced to one, and the number of processes can be reduced to two, thereby simplifying the method.

[0158] In addition, according to the comparative example, when a separate plug is inserted after inserting a plastic ball, the welding area of ​​the plastic ball and the plug must be configured to be spaced apart at a certain distance in the longitudinal direction to prevent electrolyte vapor from igniting due to the welding heat. In this case, if the injection hole is made deep in the depth direction, the width of the injection hole must be made narrow to avoid interference with the electrode assembly, and in this case, the injection efficiency may decrease.

[0159] Compared to the comparative example, according to the embodiment of the present invention, since both the temporary sealing force and the final sealing force by welding are provided with a single plug (50) component, the axial length of the pipe defining the injection port (42) can be reduced, thereby preventing the pipe from interfering with the electrode assembly. Accordingly, the inner diameter (R1) of the injection port (42) can be increased, and the injection efficiency can be improved. In addition, the phenomenon of the welding heat of the plug (50) affecting the electrode assembly or the electrolyte can be minimized.

[0160] Fig. 13 is a cross-sectional view showing a plug inserted into a lead according to another embodiment of the present invention. Fig. 14 is a cross-sectional view showing a plug and a lead combined according to another embodiment of the present invention.

[0161] 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 12, so a repeated description thereof will be omitted.

[0162] The side of the above insertion portion (51) may be a sloped surface inclined at a specified angle (θ).

[0163] The diameter (D11) of the lower surface of the above insertion portion (51) can be formed smaller than the diameter (D12) of the upper surface of the above insertion portion (51) (D11 <D12). 이에 따라 상기 삽입부(51)는 하면부터 상면 방향으로 점차 확장되는 테이퍼 형상을 가질 수 있다. 즉, 삽입부(51)는 예를 들어, 원뿔대 형상을 가질 수 있다. 이때 예를 들어, 삽입부(51)의 측면의 기울어진 각도(θ)는 대략 권취축 방향에 대해 10도 내지 20도 정도 기울어진 각도일 수 있다.

[0164] At this time, the inner diameter (R1) of the injection port (42) may be larger than the diameter (D11) of the lower surface of the insertion part (51) and smaller than the diameter (D12) of the upper surface of the insertion part (51) (D11 <R1<D12).

[0165] For example, the diameter (D12) of the upper surface of the insertion portion (51) may be approximately 0.05 mm or more and 0.40 mm or less larger than the inner diameter (R1) of the injection port (42). For example, the diameter (D12) of the upper surface of the insertion portion (51) may be approximately 0.05 mm or more and 0.20 mm or less larger than the inner diameter (R1) of the injection port (42). For example, the diameter (D12) of the upper surface of the insertion portion (51) may be approximately 0.05 mm or more and 0.10 mm or less larger than the inner diameter (R1) of the injection port (42). For example, the overlap dimension of the diameter (D12) of the upper surface of the insertion portion (51) and the inner diameter (R1) of the injection port (42) may be approximately 0.025 mm or more and 0.20 mm or less in the radial direction.

[0166] According to an embodiment of the present invention, the lower surface of the insertion portion (51) can be easily inserted into the injection port (42) due to its relatively small diameter, and the upper surface of the insertion portion (51) is formed to be larger than the inner diameter (R1) of the injection port, so that the injection port (42) can be effectively sealed. The plug (50) can be inserted into the injection port (42) by mechanical pressing. At this time, the upper outer surface of the insertion portion (51) can be strongly pressed against the inner surface of the injection port (42) while interfering with it. Therefore, it is possible to effectively block the leakage of internal electrolyte vapor or gas to the outside.

[0167] When increasing the press-fit strength to secure high sealing characteristics when press-fitting the plug (50), in severe cases, the lead (40) may sag downward, causing physical damage to the electrode assembly (20), and in this case, there is a risk of a short circuit. In the present invention, the overlap dimension and press-fit load of the plug (50) and the lead can be set so as to minimize the sagging of the lower part of the lead (40).

[0168] In other words, the plug (50) is forcibly inserted to prevent electrolyte vapor from leaking outward, which can prevent welding defects and ignition during laser welding. In other words, it is possible to prevent leakage of electrolyte vapor from entering the lead joint (52), which can cause welding defects and ignition risks. In other words, the partial pressure of flammable vapor increases due to welding heat (heat conduction) during welding, which can prevent electrolyte vapor from being released to the outside and coming into contact with the molten material during welding.

[0169] Fig. 15 is a cross-sectional view showing a lead and a plug combined according to another embodiment of the present invention.

[0170] The above lead (40) may have a body portion (41) and a plug-joint portion (43). The lead (40) may have a step formed in the radial direction based on the periphery of the injection port (e.g., the injection port (42) of FIG. 11). The lead (40) may be divided into a body portion (41) and a plug-joint portion (43) based on the step.

[0171] 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 (W) 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).

[0172] At this time, the lead connecting portion (52) 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 (W).

[0173] The plug coupling portion (43) surrounds the injection port (42) and is recessed downward in the direction of the winding axis compared to the body portion (41), and can be configured so that the lead coupling portion (52) is secured therein.

[0174] The plug joint (43) may be positioned 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.

[0175] The thickness of the plug coupling portion (43) in the winding axis direction can be formed thinner than the thickness of the body portion (41) in the winding axis direction. The plug (50) can be seated on the plug coupling portion (43). The lead coupling portion (52) of the plug (50) can be seated on the plug coupling portion (43).

[0176] Referring to Fig. 15, the lower edge of the lead joint (52) may be subjected to a rounding process (r). This rounding process (r) minimizes the step formed between the body (41) of the lead (40) and the plug joint (43) and interference during the joining, thereby enabling precise and stable joining without overlapping with the lead (40). This not only improves the ease of the assembly process but also alleviates mechanical stress concentration. Meanwhile, the shape of the lead joint (52) is not limited to the above embodiment and may be designed in various ways. In addition, other corner portions may also be subjected to the rounding process (r) in the same manner. Through this, the overall assembly and durability of the component can be further improved.

[0177] According to the above embodiment of the present invention, a structure in which the lead joint (52) of the plug (50) can be seated can be formed by forging the area around the injection port (42).

[0178] 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.

[0179] Fig. 16 is a cross-sectional view showing a plug according to another embodiment of the present invention. Fig. 17 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 15, so a repeated description thereof will be omitted.

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

[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 (52) and the insertion portion (51) can be formed relatively long compared to the forging method. Therefore, it is possible to prevent the vaporized gas of the electrolyte generated by the welding heat from directly contacting the lead joint (52). 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 using a drawing method, thereby reducing the weight of the plug (50), which can contribute to reducing the weight of the battery cell (1). 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 18 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 18. For convenience of explanation, the description may be made with reference to the drawings of Figures 1 to 17.

[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 electrolyte into the battery can (10) through the injection port (42) of the lead (40) may be included (S4). According to one embodiment, before sealing the injection port (42) with a plug (50), a step of removing residual electrolyte from the injection port (42) may be further included after the electrolyte injection is completed.

[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 (51) of the plug (50) may be configured to be inserted into the injection port (42). For example, the insertion portion (51) may be inserted into the injection port (42) in a force-fit manner. The insertion portion (51) 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 (51), 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 (51) 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 (52) of the plug (50) and the lead (40) by welding them together to secure the final sealing force.

[0197] For example, the lead joint (52) 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 (52).

[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. 19 is a drawing for explaining a battery pack according to one embodiment of the present invention. Fig. 20 is a drawing for explaining a vehicle including the battery pack of Fig. 19.

[0201] Referring to FIG. 19, 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. 20, the mileage of the vehicle can be further increased in proportion to the energy consumed.

[0205] Additionally, the battery pack (P) may further include a heat sink. The pack housing (2) may accommodate the heat sink. The heat sink may be, for example, positioned below the battery cell (1). In this case, the heat sink may be in contact with the lead (40) (e.g., the lead (40) of FIG. 9) and / or the plug (50) (e.g., the plug (50) of FIG. 9) of the battery cell (1).

[0206] Referring to FIG. 20, 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; The plug includes an insertion portion configured to be inserted into the injection port and a lead coupling portion extending upward from the insertion portion in the direction of the winding axis and seated on the lead. A battery cell in which the diameter of the above insertion portion is larger than the inner diameter of the above injection port.

2. In paragraph 1, A battery cell characterized in that the tolerance between the diameter of the insertion portion and the inner diameter of the injection port is 50 μm or more and 150 μm or less.

3. In paragraph 1, A battery cell characterized in that the diameter of the lead joint is larger than the diameter of the insertion portion.

4. In paragraph 3, A battery cell characterized in that the diameter of the lead joint is 1.1 to 1.5 times larger than the diameter of the insertion portion.

5. In paragraph 1, A battery cell characterized in that the side surface of the insertion portion and the side surface of the lead joint portion are spaced apart from each other in the horizontal direction.

6. In paragraph 1, A battery cell characterized in that the side of the above insertion portion is a sloped surface inclined at a specified angle.

7. In paragraph 6, The diameter of the lower surface of the above insertion part is formed smaller than the diameter of the upper surface of the above insertion part, A battery cell characterized in that the inner diameter of the above-mentioned injection port is larger than the diameter of the lower surface of the above-mentioned insertion portion and smaller than the diameter of the upper surface of the above-mentioned insertion portion.

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 relative to the body portion, and is configured to secure the lead coupling portion.

9. 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.

10. In paragraph 1, A battery cell characterized in that the can and the lead are thermally bonded.

11. A method for manufacturing a battery cell according to any one of claims 1 to 10, A step of covering the open end of the can with a lead while housing the electrode assembly in the can; A step of thermally bonding the edge of the lead to the can; A step of injecting electrolyte into the can through the injection port of the lead; A step of sealing the injection port by inserting the insertion part of the plug into the injection port; and A battery cell manufacturing method comprising: a step of welding the lead to a lead coupling portion that extends upward in the direction of the winding axis from the insertion portion of the plug and is seated on the lead; 12. A battery pack including a battery cell according to any one of claims 1 to 10.

13. A vehicle equipped with a battery pack as per Article 12.

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