BATTERY CELLS, AND BATTERY PACKS AND THEIR COMPONENTS

Abstract

The battery cell of the invention may consist of an electrode assembly in which the first electrode, the second electrode, and the separator placed between them are wound around a winding shaft; a housing constructed to contain the electrode assembly through an open end formed on one side; an open end cover with a central nozzle; and a sealing element constructed to seal the nozzle, in which the sealing element may have a sealing part pressed into the nozzle and in close contact with the inner circumferential surface of the nozzle; and a welded part welded to the inner circumferential surface of the nozzle.

Description

Battery cells, battery packs containing the same, and vehicles

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

[0002] This application claims priority to Korean Patent Application No. 10-2024-0075541, filed on June 11, 2024, and all contents disclosed in the specification and drawings of the said application are incorporated herein by reference.

[0003] This application claims priority to Korean Patent Application No. 10-2025-0075563, filed on June 10, 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 gasket (91) to secure the lead (40). Since crimping is a physical fixing method that does not apply heat, it is possible to perform the operation while the electrolyte is poured into the can. 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 more complex than welding, and thus has limitations in securing the internal volume of the can 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, the seam welding method is more advantageous in securing electrical capacity relative to the same volume of the battery can.

[0011] However, if the open end of the battery can is covered with a lead and welded after filling the battery can with electrolyte, there is a possibility that the electrolyte may deteriorate or ignite due to the high temperature generated by welding.

[0012] For example, if the can and lid are made of stainless steel, the surface temperature can rise to 1400 degrees Celsius, the melting point of stainless steel. This high temperature can cause the electrolyte to ignite.

[0013] Accordingly, when it is desired to fix 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 provided 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 provided at the bottom of the lead or the battery can, and after the injection is completed, the filler port is sealed.

[0014] Therefore, there may be a need for a sealing finishing method that eliminates gas leakage due to vaporization of the electrolyte by welding heat and has enhanced sealing power.

[0015]

[0016] The present invention has been prepared to solve the problems described above, and the problem to be solved by the present invention is to provide a battery cell with an improved sealing structure of a liquid filler port and a method for manufacturing the same.

[0017] The present invention has been devised to solve the above-described problem, and provides a sealing structure of an injection port and a sealing method thereof, which can inject electrolyte through an injection port, thereby enabling seam welding of a lead and a can before electrolyte injection, and sealing the injection port so that a gas channel is not formed after injection.

[0018] In addition, the present invention aims to provide a sealing structure for a liquid injection port and a sealing method thereof, which are free from defects in the welding area 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 sealing structure of a liquid injection port and a sealing method thereof that can minimize the number of parts and reduce assembly work.

[0020] In addition, the present invention seeks to provide a battery cell structure in which an electrolyte can be smoothly filled when poured into the inside of a can.

[0021] In addition, the present invention aims to provide a sealing structure for a liquid filler port that enables sealing of the liquid filler port without applying a strong force when sealing the liquid filler port, a sealing method thereof, and a battery cell using the same.

[0022] 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.

[0023] 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.

[0024]

[0025] The battery cell of the present invention for solving the above-described problem 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 on one side, a lid covering the open end and having a liquid injection port formed in the center, and a sealing member configured to seal the liquid injection port, wherein the sealing member may have a sealing portion that is press-fitted into the liquid injection port and is in close contact with the inner surface of the liquid injection port, and a welding portion that is mutually welded with the inner surface of the liquid injection port.

[0026] The above-mentioned contact portion and the above-mentioned welding portion may be spaced apart from each other in the direction of the winding axis.

[0027] The above lead may include a plate portion having a hole and a tube portion extending inwardly in the direction of the winding axis from the inner periphery of the plate portion defining the hole and forming the injection port.

[0028] The above-mentioned pipe may have a tapered section in which the inner diameter decreases as it goes inward in the direction of the winding axis.

[0029] The maximum outer diameter of the above sealing member may be larger than the minimum inner diameter of the tapered section of the above pipe.

[0030] The maximum outer diameter of the above sealing member may be greater than the minimum inner diameter of the above tapered section by 0.05 mm or more and 0.40 mm or less.

[0031] The above-mentioned sealing member's contact portion may be located on the inner side in the winding axis direction relative to the center line of the sealing member.

[0032] When the sealing member is pressed into the injection port, the pipe section may have an inner diameter that is expanded radially outward in a predetermined section of the tapered section that is in contact with the sealing section.

[0033] The above welding portion may be positioned outside the above contact portion in the direction of the winding axis.

[0034] The above sealing member may be in the shape of a ball.

[0035] The above can and lid may be heat bonded.

[0036] The method for manufacturing a battery cell of the present invention may include a step of covering the open end with the lead while the electrode assembly is accommodated in the can, a step of joining the edge of the lead to the can, a step of injecting an electrolyte into the can through a filling port of the lead joined to the can, a step of pressing the sealing member into the filling port after the electrolyte is injected to bring the filling port and the sealing member into close contact, and a step of welding the sealing member and the inner circumferential surface of the filling port.

[0037] The pressing load of the above sealing member may be 1 ton or less.

[0038] The sealing force of the above-mentioned injection port and the above-mentioned sealing member is 10 based on the He leak standard. -5 10 inland -3 It could be atm·cc / s.

[0039] The present invention also provides a battery pack including a battery cell according to the present invention.

[0040] The present invention also provides a vehicle equipped with a battery pack according to the present invention.

[0041]

[0042] According to the present invention, a temporary sealing force is secured by pressing a sealing member into the injection port before welding to a degree that a sealing force can be secured against the pressure of the vaporized gas of the electrolyte generated by the heat generated when welding the injection port and the sealing member, and in this state, the sealing member and the inner surface of the injection port are welded to secure a final sealing force higher than the temporary sealing force.

[0043] According to the present invention, since the temporary sealing force is lower than the final sealing force, the pressing force of the sealing member can be significantly reduced compared to a case where the sealing force is secured only by pressing, and thus permanent deformation of the lid or can due to the pressing force can be minimized.

[0044] According to the present invention, since welding is performed after securing temporary sealing force, the influence of electrolyte vaporized inside the battery cell due to welding heat during the welding process on the welding quality is eliminated, and the welding quality can be improved.

[0045] According to the present invention, a single sealing member component can provide a sealing portion for a liquid injection port and a weld portion for the inner surface of the liquid injection port. This reduces the number of components and assembly work.

[0046] Furthermore, according to the present invention, since a single sealing member component provides both temporary and final sealing forces, the length of the tube defining the injection port in the direction of the winding axis can be reduced, thereby preventing the tube from interfering with the electrode assembly. Accordingly, the inner diameter of the injection port can be increased, and injection efficiency can be improved.

[0047] In addition, according to the present invention, by shortening the extension length of the pipe, the phenomenon in which the welding heat of the sealing member affects the electrode assembly or the electrolyte can be minimized.

[0048] According to the present invention, since the sealing member and the inner surface of the injection port are in close contact with each other in the tapered section of the pipe defining the injection port, the pressing force for forming the close contact can be reduced, and it can be easily formed by separating the close contact and the welding portion.

[0049] According to the present invention, since the sealing member is positioned apart from the welding member, the sealing member may not melt due to the welding heat during the welding process. In other words, the welding heat may not cause the sealing force of the sealing member to be lost.

[0050] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0051]

[0052] 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.

[0053] Figure 1 is a drawing showing a method of fixing a lead and a battery can using a conventional crimping method.

[0054] Figure 2 is a perspective view of a battery cell according to one embodiment of the present invention.

[0055] 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.

[0056] Fig. 4 is a perspective view of an electrode assembly manufactured by winding the laminate of Fig. 3 into a jelly-roll shape.

[0057] 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.

[0058] Figure 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.

[0059] 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.

[0060] Fig. 9 is a cross-sectional view showing a state in which the injection port of a lead is sealed by a sealing member according to one embodiment of the present invention.

[0061] Fig. 10 is a cross-sectional view showing the appearance before a sealing member is inserted into the injection port of a lead according to one embodiment of the present invention.

[0062] Fig. 11 is a cross-sectional view showing the appearance after a sealing member is inserted into the injection port of a lead according to one embodiment of the present invention.

[0063] Fig. 12 is a cross-sectional view showing the welding of a sealing member and a lead injection port according to one embodiment of the present invention.

[0064] Figure 13 is a cross-sectional view after welding of Figure 12.

[0065] Fig. 14 is a cross-sectional view showing a state in which the injection port of a lead is sealed by a sealing member according to another embodiment of the present invention.

[0066] Fig. 15 is a cross-sectional view showing a state in which the injection port of a lead is sealed by a sealing member according to another embodiment of the present invention.

[0067] Figure 16 is a flowchart of a method for manufacturing a battery cell to which the liquid cap closure structure of the present invention is applied.

[0068] FIG. 17 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0069] FIG. 18 is a drawing for explaining a vehicle including the battery pack of FIG. 17.

[0070]

[0071] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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 into 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.

[0086] Hereinafter, with reference to FIGS. 2 to 7, an embodiment of a battery cell (1) to which the liquid cap sealing structure of the present invention is applied will be described in detail.

[0087] A battery cell (1) can be manufactured by embedding a cylindrical electrode assembly (20) inside a cylindrical battery can (10).

[0088] 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).

[0089] 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.

[0090] 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).

[0091] 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.

[0092] 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.

[0093] 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 gasket (14) interposed therebetween. The gasket (14) is interposed between the first electrode terminal (13) and the bottom portion (12), 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).

[0094] 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.

[0095] 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.

[0096] 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).

[0097] 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.

[0098] An electrode assembly (20) is accommodated within the can (10). The electrode assembly (20) can be manufactured by preparing a first electrode (21), a second electrode (22), and a separator (28) having a predetermined width and extending in the longitudinal direction as illustrated in FIG. 3, forming a laminated body by stacking the first electrode (21), the separator (28), the second electrode (22), and the separator (28) in that order, and then winding this around a core shaft as illustrated in FIG. 4, into a cylindrical jelly-roll.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] In the above-mentioned blank portion (26), notches can be formed at a predetermined interval to form flag-shaped notching tabs (27).

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] In the jelly roll-shaped electrode assembly (20), the notched tab (27) can be bent radially and flattened as illustrated in FIG. 4. The notched tab (27) can be bent radially inward or outward. In the embodiment, a structure in which the notched tab (27) is bent radially inward is exemplified.

[0108] 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).

[0109] 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.

[0110] 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).

[0111] 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.

[0112] The above-mentioned collector plate (31, 32) can be manufactured by punching, trimming, piercing, and bending a metal sheet.

[0113] 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 core hollow portion of the electrode assembly (20).

[0114] 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.

[0115] Referring to FIG. 6, the second collector plate (32) may include an inner ring (321) that defines a hole (322) corresponding to the core hollow portion of the electrode assembly (20) and is provided in a form that surrounds the core hollow portion, a second electrode connection portion (323) that extends radially from the inner ring portion (321), and a second terminal connection portion (324) that is positioned on the centrifugal side of the second electrode connection portion (323) and is connected to the inner ring portion (321). The second terminal connection portion (324) may have an outer ring form that surrounds the edge of the second collector plate (32).

[0116] 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.

[0117] However, the shape and structure of the first collector plate (31) and the second collector plate (32) are not limited to the above embodiment and can be designed in various ways.

[0118] 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).

[0119] 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).

[0120] 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, the first collector plate (31) and the first electrode terminal (13) can be electrically connected and fixed to each other in various ways. 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.

[0121] 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.

[0122] The can (10) and the lead (40) can be thermally bonded. The front end of the side wall of the battery can (10) and the edge of the lead (40) can be brought into contact with each other and welded along the circumference. This can be defined as a seam welding method. Since the fixing structure is simple, the volume of the electrode assembly that can be accommodated inside the can can be secured accordingly. Therefore, the seam welding method is more advantageous in securing electric capacity per unit volume of the can.

[0123] Specifically, when it is desired to fix the open end of the can (10) by deep welding the lead (40), a method may be applied in which a can (10) having a liquid inlet provided at the bottom or a lead (40) having a liquid inlet provided therein 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 lead (40) or the liquid inlet provided at the bottom of the can (10), and after the injection is completed, the liquid inlet is sealed with a plug or a sealing member (50).

[0124] 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.

[0125] The inner surface of the lead (40) is electrically connected by being joined to the tab of the second electrode of the electrode assembly (20) housed inside the can (10) of the battery cell (1), and the edge of the lead (40) can be electrically connected by being joined to the edge of the open end side of the can (10).

[0126] 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).

[0127] 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 pressing and forming a metal plate.

[0128] Fig. 8 is a cross-sectional view showing a state in which a can containing an electrode assembly according to an embodiment of the present invention is covered and sealed with a lid. Fig. 9 is a cross-sectional view showing a state in which a liquid inlet of a lid is sealed by a sealing member according to an embodiment of the present invention. Fig. 10 is a cross-sectional view showing a state before a sealing member is inserted into a liquid inlet of a lid according to an embodiment of the present invention. Fig. 11 is a cross-sectional view showing a state after a sealing member is inserted into a liquid inlet of a lid according to an embodiment of the present invention. Fig. 12 is a cross-sectional view showing a state in which a sealing member and a liquid inlet of a lid are welded according to an embodiment of the present invention. Fig. 13 is a cross-sectional view of Fig. 12 after welding.

[0129] Referring to FIGS. 8 to 13, the injection port (42) may be provided in the central portion of the lead (40). The injection port (42) may, for example, serve as an electrolyte injection port.

[0130] The injection port (42) can be blocked by a sealing member (50) to be described later. For example, the sealing member (50) can be pressed into the injection port (42). By blocking the injection port (42) by the sealing member (50), the battery cell (1) can be guaranteed to be sealed.

[0131] The center of the injection port (42) may 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) may be located above the winding center hole (H) of the electrode assembly (20) in the winding axis direction.

[0132] Meanwhile, the injection port (42) may be configured to discharge gases generated during a pre-charge process, which will be described later. That is, after a degassing process in which all gases generated during the pre-charge process are discharged through the injection port (42), the sealing member (50) may be configured to be coupled onto the injection port (42). Accordingly, the swelling phenomenon of the battery cell (1) can be reduced.

[0133] The lead (40) may include a plate portion (41) having a hole, and a tube portion (44) extending inward in the direction of the winding axis from the inner circumference of the plate portion (41) defining the hole.

[0134] For example, the thickness of the plate portion (41) may be approximately 0.3 mm or more and 1.0 mm or less. The injection port (42) may be manufactured by drawing a micro-hole portion provided in the center of the disc-shaped plate portion (41) of the lid (40). For example, after punching a micro-hole in the plate portion (41), it may be pushed into a mold in the shape of a rod (determining the inner diameter of the injection port) to form a funnel-shaped tube portion (44), thereby forming the injection port (42). That is, the injection port (42) may be formed by plastic processing of the lid (40).

[0135] The pipe (44) can form a liquid injection port (42). The liquid injection port (42) can be defined by a pipe (44) extending from the center of the lead (40) in the direction of the winding axis. That is, the inner surface of the pipe (44) can be defined as the liquid injection port (42). Hereinafter, the inner surface of the liquid injection port (42) can be understood to refer to the inner surface of the pipe (44).

[0136] The above-mentioned injection port (42) may have a penetration section extending in the direction of the winding axis, and may have a penetration cross-section defined by a portion where an imaginary plane extending in a radial direction perpendicular to the direction of the winding axis intersects the inner surface of the injection port (42).

[0137] For example, the penetration cross-section of the injection port (42) defined by the inner surface of the above-mentioned pipe (44) may be circular.

[0138] Referring to FIG. 10, the pipe (44) may have a tapered section (45) whose inner diameter decreases as it goes inward in the winding axis direction. The pipe (44) may have a tapered section (45) whose penetration area gradually decreases as it goes inward in the winding axis direction. That is, the pipe (44) defining the injection port (42) may have a circular tapered tube shape as illustrated. The tapered section (45) may be configured as a straight inclined surface inclined at a predetermined taper angle (θ) with respect to the winding axis direction. That is, the tapered section (45) may have, for example, a conical shape. In this case, for example, the taper angle (θ) may be an angle inclined by approximately 10 to 20 degrees with respect to the winding axis direction.

[0139] After the injection of the electrolyte is completed, the injection port (42) can be sealed with a sealing member (50). The sealing member (50) can be configured to seal the injection port (42). The sealing member (50) can be configured to be inserted into the injection port (42). The sealing member (50) can penetrate the injection port (42). By inserting the sealing member (50) into the injection port (42) of the lid (40), the sealing property of the battery cell (1) can be secured. The sealing member (50) can penetrate the injection port (42) formed in the lid (40) to seal the outside and inside of the can (10), thereby preventing leakage of the electrolyte.

[0140] 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 (100), 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.

[0141] The sealing member (50) may be a spherical metal ball. The sealing member (50) may be made of, for example, SUS material. If the lead (40) has a second polarity, aluminum cannot be used as the sealing member (50). If the sealing member (50) is made of SUS material, corrosion by the electrolyte can be prevented.

[0142] Referring to FIG. 10, the maximum outer diameter (R) of the sealing member (50) may be larger than the minimum inner diameter (r) of the tapered section (45) of the pipe portion (44). For example, the maximum outer diameter (R) of the sealing member (50) may be larger than the minimum inner diameter (r) of the tapered section (45) by approximately 0.05 mm or more and 0.40 mm or less. For example, the maximum outer diameter (R) of the sealing member (50) may be larger than the minimum inner diameter (r) of the tapered section (45) by approximately 0.05 mm or more and 0.20 mm or less. For example, the maximum outer diameter (R) of the sealing member (50) may be larger than the minimum inner diameter (r) of the tapered section (45) by approximately 0.05 mm or more and 0.10 mm or less. For example, the overlap dimension of the sealing member (50) and the pipe portion (44) before pressing may be approximately 0.025 mm or more and 0.20 mm or less in the radial direction.

[0143] That is, the sealing is performed by physically pressing in a sealing member (50) having a larger diameter than the inner diameter of the pipe (44). The sealing member (50) can be pressed into the inside of the injection port (42). The sealing member (50) can be inserted into the inside of the injection port (42) by mechanical pressing. At this time, for example, the pressing load of the sealing member (50) can be approximately 1 ton or less. For example, the pressing condition of the sealing member (50) can be approximately 1 ton or less.

[0144] When increasing the press-fit strength to secure high sealing characteristics when press-fitting the sealing member (50), there is a risk of a short circuit if the lead (40) sags downwards and causes physical damage to the electrode assembly (20). In the present invention, the overlap dimension and press-fit load of the sealing member (50) and the pipe (44) can be set so as to minimize the sagging of the lower part of the lead (40).

[0145] In the process of pressing the sealing member (50) into the injection port (42), at least a portion of the tapered section (45) may be deformed by an external load. Specifically, when the sealing member (50) is pressed into the injection port (42), the inner diameter of the pipe (44) may be deformed to expand radially outward in a predetermined section that contacts the tapered section (45).

[0146] For example, referring to FIG. 10, the pre-press taper section (45) may be configured as a straight inclined surface inclined at a predetermined taper angle (θ) with respect to the winding axis direction. For example, the taper angle (θ) may be an angle inclined at approximately 10 to 20 degrees with respect to the winding axis direction.

[0147] When the sealing member (50) is pressed in, the tapered section (45) can receive a force radially outward by the sealing member (50). The sealing member (50) can induce a press load that acts radially outward on the inner surface of the tapered section (45). Accordingly, the end of the tapered section (45) can expand or bend radially outward. Due to this, the taper angle (θ') after the press-in can be smaller than the taper angle (θ) before the press-in. For example, the taper angle (θ') after the press-in can be an angle inclined by approximately 1 to 10 degrees with respect to the winding axis direction. In addition, since the tapered section (45) is formed as a curved inclined surface that is bent radially outward, the taper angle (θ') after the press-in may not be constant depending on the height.

[0148] According to one embodiment, the rate at which the radius defining the penetration cross-section of the injection port (42) decreases as it goes inward in the winding axis direction may decrease. That is, the radius defining the penetration cross-section of the tapered section (45) may gradually decrease as it goes inward in the winding axis direction, but the rate at which it decreases may be reduced. However, the shape and structure of the tapered section (45) are not limited by the above embodiment and may be designed in various ways. For example, according to another embodiment, the rate at which the cross-sectional radius of the tapered section (45) defining the penetration cross-section of the injection port (42) decreases as it goes inward in the winding axis direction may be constant.

[0149] According to the above-described embodiment of the present invention, a temporary sealing force can be secured by press-fitting the sealing member (50) into the liquid injection port (42) before the welding process of the liquid injection port (42) and the sealing member (50). Here, the 'temporary sealing force' may mean a sealing force at a level that can secure airtightness to the extent that the vaporized gas of the electrolyte generated during the process of welding the liquid injection port (42) and the sealing member (50) does not leak to the outside through the bonding interface between the liquid injection port (42) and the sealing member (50) when the electrolyte is vaporized. In other words, this temporary sealing force may mean that, under the condition that the electrolyte is converted to vapor and the internal pressure increases, a mechanical sealing force sufficient to resist the corresponding pressure can be secured.

[0150] However, the final sealing force may not be secured by only pressing the sealing member (50). That is, it may be difficult to completely secure the final sealing performance by only pressing. For example, the temporary sealing force secured by pressing the sealing member (50) may be approximately 10-5 to 10-3 atm·cc / s based on the He leak. Here, the He leak test may mean a test that quantitatively evaluates whether there is a micro-leakage of the target component by using helium gas (He) as a tracer gas for leak detection. However, since this temporary sealing force is sufficient to suppress vapor emission, it can prevent welding defects and the risk of electrolyte ignition during subsequent welding.

[0151] 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 sealing member (50) can be reduced compared to a case where the sealing force is secured only by press-fitting. 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.

[0152] The above sealing member (50) may have a sealing portion (51) that is in close contact with the inner surface of the injection port (42) and a welding portion (52) that is welded to the inner surface of the injection port (42).

[0153] At this time, the sealing member (50) is pressed into the injection port (42) and the area where it is in close contact with the inner surface of the injection port (42) can be defined as a contact portion (51). The contact portion (51) is a portion that directly contacts the inner surface of the injection port (42), and may refer to a contact area formed in a ring shape along the outer surface of the sealing member (50). The contact portion (51) may refer to a region where the outer surface of the sealing member (50) pressed into the pipe portion (44) is in radial contact with the inner surface of the pipe portion (44) in the tapered section (45). That is, the contact portion (51) may be a joint interface where the inner surface of the injection port (42) and the outer surface of the sealing member (50) are in direct contact in the radial direction.

[0154] Since the above pipe portion (44) has a tapered shape, the sealing portion (51) can be arranged inside the center line (C) of the sealing member (50) in the winding axis direction. Referring to Fig. 11, a horizontal line connecting the sealing portions (51) can be defined as a sealing line (S). That is, the sealing line (S) can be located inside the center line (C) in the winding axis direction. This may be due to the geometric characteristic that the inner diameter of the pipe portion (44) gradually decreases as it goes inside in the winding axis direction. As the slope of the taper section (45) with respect to the winding axis direction, i.e., the taper angle (θ), increases, the sealing portion (51) can move deeper in the winding axis direction in the center line (C) of the sealing member (50). That is, the position of the sealing member (51) can be set according to the displacement induced by the tapered section (45) of the sealing member (50).

[0155] Referring to FIGS. 11 and 12, after the sealing member (50) is pressed into the injection port (42), the sealing member (50) and the lead (40) can be welded. For example, the sealing member (50) and the lead (40) can be laser welded. Laser welding can be defined as a process of melting and joining metals using a laser beam having a high energy density. Referring to FIG. 12, the sealing member (50) and the inner surface of the pipe part (44) can be welded by irradiating a laser (L). Then, a welded portion (52) can be formed as illustrated in FIG. 13.

[0156] The above welding portion (52) may be spaced apart from the above sealing portion (51) in the winding axis direction. The welding portion (52) may be positioned outside the sealing portion (51) in the winding axis direction. Since the sealing portion (51) is positioned apart from the welding portion (52), it is possible to obtain superior sealing characteristics in terms of airtightness required in the battery cell (1) in a manner that avoids welding defects and the risk of electrolyte ignition.

[0157] The welded portion (52) may be positioned further outward in the direction of the winding axis than the contact portion (51) of the sealing member (50). Referring to Fig. 11, a horizontal line connecting the welded portion (52) may be defined as a welding line (W). That is, the welding line (W) may be positioned further outward in the direction of the winding axis than the contact line (S).

[0158] The welded portion (52) may be positioned outside the center line (C) of the sealing member (50) in the direction of the winding axis. That is, the welded line (W) may be positioned outside the center line (C) of the sealing member (50) in the direction of the winding axis.

[0159] This may be due to geometric constraints that prevent the laser from reaching the sealing portion (51) because the laser is irradiated from the upper side of the winding shaft. According to the above-described embodiment of the present invention, since the sealing portion (51) is spaced apart from the welding portion (52), the sealing portion (51) may not be melted due to the welding heat during the welding process. In other words, the welding heat may not cause the temporary sealing force of the sealing portion (51) to be lost.

[0160] Referring to Fig. 11, the inner surface of the sealing member (50) and the injection port (42) may be spaced apart in the radial direction in the pre-weld welded portion (52). That is, unlike the contact portion (51), the inner surface of the sealing member (50) and the injection port (42) may not be joined in the pre-weld welded portion (52). During laser (L) welding, the inner surface of the sealing member (50) and / or the injection port (42) may be thermally joined while melting the inner surface of the sealing member (50) and / or the injection port (42). Therefore, referring to Fig. 13, the inner surface of the sealing member (50) and the injection port (42) after melting may be formed integrally.

[0161] Referring to Fig. 12, the tapered section (45) of the pipe portion (44) and the upper edge of the sealing member (50) are welded, and the radial gap between the sealing member (50) and the tapered section (45) may become narrower toward the inside in the winding axis direction. Therefore, when a laser beam is irradiated during welding, multiple reflections may occur in the order of sealing members i, ii, iii, and iv between the outer surface of the sealing member (50) and the inner surface of the pipe portion (44). At this time, as the reflection path becomes longer, the laser cannot penetrate deep into the winding axis direction, and is absorbed and extinguished near the irradiation point, and its energy may be mainly concentrated and transmitted near the welding portion (52). In addition, since the contact portion (51) is arranged slightly inward in the winding axis direction than the center line (C) of the sealing member (50), the possibility of the laser reaching the contact portion (51) may be further reduced. According to the above-described embodiment of the present invention, since the welding heat source is concentrated on the outer upper portion of the sealing member (50), the effect of heat can be concentrated on the welding portion (52). In addition, the sealing force of the sealing portion (51) can be maintained without being weakened by the welding heat and the sealing properties can be maintained.

[0162] According to the above-described embodiment of the present invention, a temporary sealing force can be first secured by pressing the sealing member (50) into the injection port (42) before thermal bonding to an extent that the sealing force can be secured against the pressure of the vaporized gas of the electrolyte generated by the welding heat generated when thermally bonding the injection port (42) and the sealing member (50). Then, the sealing member (50) and the inner surface of the injection port (42) are thermally bonded to secure a final sealing force higher than the temporary sealing force. Therefore, the final sealing force can be greater than the temporary sealing force. For example, the final sealing force that can be secured by welding is approximately 10 when the He leak standard leakage amount is -7 It can be less than atm.cc / s, which means that high confidentiality can be ensured.

[0163] According to the above-described embodiment of the present invention, since thermal bonding is performed after securing temporary sealing force, the phenomenon of gas channels being formed or cracks occurring during the thermal bonding process can be prevented, thereby preventing defects in the welded portion (52).

[0164] 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.

[0165] In addition, according to the above-described embodiment of the present invention, a sealing member (50) component can be used to form a sealing portion (51) for a liquid injection port (42), and also to form a weld portion (52) with the inner surface of the liquid injection port (42). Accordingly, the number of components can be reduced, and assembly work can be reduced.

[0166] In addition, according to the above-described embodiment of the present invention, since both temporary sealing force and final sealing force are provided by a single sealing member (50) component, the length of the pipe portion (44) defining the injection port (42) in the direction of the winding axis can be reduced, so that the pipe portion (44) does not interfere with the electrode assembly (20). Accordingly, the inner diameter of the injection port (42) can be increased, and the injection efficiency can be improved. In addition, the phenomenon in which the welding heat of the sealing member (50) affects the electrode assembly (20) or the electrolyte can be minimized.

[0167] Fig. 14 is a cross-sectional view showing a state in which the injection port of a lead is sealed by a sealing member according to another embodiment of the present invention.

[0168] According to one embodiment, the pipe (44) may further include a protrusion (46) protruding inwardly. The protrusion (46) may be formed to protrude inwardly from the inner surface of the pipe (44).

[0169] A plurality of protrusions (46) may be provided. The plurality of protrusions (46) may be spaced apart along the winding axis direction and formed at a set height along the inner circumference of the pipe (44). This configuration may increase the frictional force with the sealing member (50), thereby improving sealing performance.

[0170] For example, the protrusion (46) may have a lower protrusion (46a) located on the lower side of the pipe part (44) and an upper protrusion (46b) located on the upper side of the pipe part (44). The lower protrusion (46a) and the upper protrusion (46b) may be spaced apart from each other in the winding axis direction. The lower protrusions (46a) and the upper protrusions (46b) may each be provided in multiple numbers, and may be positioned at a specified height along the inner surface of the pipe part (44).

[0171] At this time, the sealing member (50) may be pressed into the pipe (44) and positioned between the lower protrusion (46a) and the upper protrusion (46b). The sealing member (50) may be seated between the lower protrusion (46a) and the upper protrusion (46b). That is, the protrusion (46) may serve to fix the position of the sealing member (50).

[0172] Accordingly, the sealing member (50) can be fixed to a pre-set position without being affected by the pressing strength or positional deviation, and it may be possible to structurally prepare a mounting portion of the sealing member in advance.

[0173] In addition, the protrusion (46) can help to fix the position of the sealing member (50) and at the same time increase the contact area with the pipe (44) to increase the frictional force, thereby contributing to the improvement of the overall sealing force.

[0174] Additionally, the upper protrusion (46b) can be utilized as a welding melting point when welding the sealing member (50) and the pipe part (44). The upper protrusion (46b) can be located at the welding part (52) or an adjacent part thereof. Therefore, the upper protrusion (46b) can be melted together when laser welding the sealing member (50) and the pipe part (44).

[0175] According to the above-described embodiment of the present invention, the upper protrusion (46b) can form a starting point for laser welding. Accordingly, it is possible to structurally prepare a melting location in advance.

[0176] Fig. 15 is a cross-sectional view showing a state in which the injection port of a lead is sealed by a sealing member according to another embodiment of the present invention.

[0177] According to one embodiment, one end surface of the sealing member (50) may be oval. The horizontal outer diameter (R1) of the sealing member (50) may be formed longer than the vertical outer diameter (R2). In other words, the sealing member (50) may have a relatively expanded shape in the horizontal direction and a relatively thin shape in the vertical direction.

[0178] According to the above-described embodiment of the present invention, by setting the cross-sectional shape of the sealing member (50) to an oval shape, the horizontal width of the injection port (42) can be increased. Accordingly, the inflow path for injecting the electrolyte is further secured, effectively preventing the phenomenon of the electrolyte contacting or leaking into the pipe (44) or surrounding components during the injection process and causing contamination. Consequently, electrolyte waste can be minimized and the stability of the manufacturing process can be improved.

[0179] In addition, according to the above-described embodiment of the present invention, the elliptical shape of the sealing member (50) enables the vertical height of the injection port (42) to be minimized, thereby reducing the height of the pipe portion (44). When the height of the pipe portion (44) is reduced, more space can be secured within the can (10) that accommodates it, thereby reducing the possibility of interference between the electrode assembly (20) and the pipe portion (44).

[0180] Additionally, by minimizing the space occupied by the cap (44) and maximizing the capacity of the electrode assembly (20), a larger effective electrode area can be secured within the same cell structure. Accordingly, the overall energy density can be improved.

[0181] Figure 16 is a flowchart of a method for manufacturing a battery cell to which the liquid cap closure structure of the present invention is applied.

[0182] Referring to FIG. 16 below, a method for manufacturing a battery cell (1) according to an embodiment of the present invention will be described.

[0183] 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.

[0184]

[0185] 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).

[0186] 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).

[0187]

[0188] A step of thermally bonding the edge of the lead to the can may be included (S3).

[0189] The first collector plate (31) can be thermally bonded to the first electrode terminal (13). In addition, the open end of the can (10) is covered with a lead (40) to seal the can, 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 bonding the second collector plate (32) to the can (10) and / or the lead (40), and thermally bonding the lead (40) and the can (10).

[0190] 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, in addition to this, 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 to the first collector plate (31) and the first electrode terminal (13) as long as they can be electrically connected and fixed to each other.

[0191] With the electrode assembly (20) housed in the can (10), the open end of the can (10) can be sealed by covering it with a lead (40).

[0192] 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 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.

[0193] The inner surface of the lead (40) is electrically connected by being joined to the tab of the second electrode of the electrode assembly (20) housed inside the can (10) of the battery cell (1), and the edge of the lead (40) can be electrically connected by being joined to the edge of the open end side of the can (10).

[0194] 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).

[0195] Next, a step may be included of pressing the sealing member into the injection port after the electrolyte is injected to bring the injection port and the sealing member into close contact (S5).

[0196] By applying the previously described injection port sealing structure, the injection port (42) of the battery can (10) can be sealed with a sealing member (50). The sealing member (50) can be pressed into the injection port (42). The sealing member (50) can be inserted into the injection port (42) by mechanical pressing. At this time, for example, the pressing load of the sealing member (50) can be approximately 1 ton or less. For example, the pressing condition of the sealing member (50) can be approximately 1 ton or less.

[0197] When increasing the press-fit strength to secure high sealing characteristics when press-fitting the sealing member (50), there is a risk of a short circuit if the lead (40) sags downwards and causes physical damage to the electrode assembly (20). In the present invention, the overlap dimension and press-fit load of the sealing member (50) and the pipe (44) can be set so as to minimize the sagging of the lower part of the lead (40).

[0198] In the process of pressing the sealing member (50) into the injection port (42), at least a portion of the tapered section (45) may be deformed by an external load. Specifically, when the sealing member (50) is pressed into the injection port (42), the inner diameter of the pipe (44) may be deformed to expand radially outward in a predetermined section that contacts the tapered section (45).

[0199] According to the above-described embodiment of the present invention, a temporary sealing force can be secured by press-fitting the sealing member (50) into the liquid injection port (42) before the welding process of the liquid injection port (42) and the sealing member (50). Here, the 'temporary sealing force' may mean a sealing force at a level that can secure airtightness to the extent that the vaporized gas of the electrolyte generated during the process of welding the liquid injection port (42) and the sealing member (50) does not leak to the outside through the bonding interface between the liquid injection port (42) and the sealing member (50) when the electrolyte is vaporized. In other words, this temporary sealing force may mean that, under the condition that the electrolyte is converted to vapor and the internal pressure increases, a mechanical sealing force sufficient to resist the corresponding pressure can be secured.

[0200] However, the final sealing force may not be secured by only pressing the sealing member (50). That is, it may be difficult to completely secure the final sealing performance by only pressing. For example, the temporary sealing force secured by pressing the sealing member (50) may be approximately 10-5 to 10-3 atm·cc / s based on the He leak. Here, the He leak test may mean a test that quantitatively evaluates whether there is a micro-leakage of the target component by using helium gas (He) as a tracer gas for leak detection. However, since this temporary sealing force is sufficient to suppress vapor emission, it can prevent welding defects and the risk of electrolyte ignition during subsequent welding.

[0201] Finally, a step of welding the inner surface of the sealing member (50) and the injection port (42) may be included (S6).

[0202] The above sealing finish can be achieved by first securing a temporary sealing force by pressing the sealing member (50) into the liquid injection port (42), and then sealing the upper edge of the sealing member (50) and the inner circumference of the pipe (44) defining the liquid injection port (42) by welding to secure the final sealing force.

[0203] For example, the sealing member (50) and the lead (40) can be laser welded. Laser welding can be defined as a process of melting and joining metals using a laser beam with high energy density. Referring to Fig. 12, the sealing member (50) and the inner surface of the pipe part (44) can be welded by irradiating the laser (L).

[0204] 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.

[0205] According to the above-described embodiment of the present invention, since thermal bonding is performed after securing temporary sealing force, the phenomenon of gas channels being formed or cracks occurring during the thermal bonding process can be prevented, thereby preventing defects in the welded portion (52).

[0206] 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.

[0207] In addition, according to the above-described embodiment of the present invention, a sealing member (50) component can be used to form a sealing portion (51) for a liquid injection port (42), and also to form a weld portion (52) with the inner surface of the liquid injection port (42). Accordingly, the number of components can be reduced, and assembly work can be reduced.

[0208] Fig. 17 is a drawing for explaining a battery pack according to one embodiment of the present invention. Fig. 18 is a drawing for explaining a vehicle including the battery pack of Fig. 17.

[0209] Referring to FIG. 17, 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.

[0210] 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 pack case, a relay, a current sensor, etc.

[0211] 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.

[0212] 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. 17, the mileage of the vehicle can be further increased in proportion to the energy consumed.

[0213] Referring to FIG. 18, a vehicle (M) according to the present invention may include at least one battery pack (P) according to the present invention.

[0214] 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.

[0215] 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 sealing member configured to seal the above-mentioned injection port; A battery cell having a sealing member that is pressed into the injection port and is in close contact with the inner surface of the injection port; and a welding member that is mutually welded with the inner surface of the injection port.

2. In claim 1, A battery cell characterized in that the above-mentioned contact portion and the above-mentioned welding portion are mutually spaced apart in the direction of the winding axis.

3. In claim 1, A battery cell characterized in that the lead includes a plate portion having a hole and a tube portion extending inwardly in the direction of the winding axis from the inner periphery of the plate portion defining the hole and forming the injection port.

4. In claim 3, A battery cell characterized in that the above-mentioned pipe has a tapered section whose inner diameter decreases as it goes inward in the direction of the winding axis.

5. In claim 4, A battery cell characterized in that the maximum outer diameter of the sealing member is larger than the minimum inner diameter of the tapered section of the pipe.

6. In claim 4, A battery cell characterized in that the maximum outer diameter of the sealing member is greater than the minimum inner diameter of the tapered section by 0.05 mm or more and 0.40 mm or less.

7. In claim 1, A battery cell characterized in that the sealing member's sealing portion is located inward in the winding axis direction from the center line of the sealing member.

8. In claim 4, A battery cell characterized in that when the sealing member is pressed into the injection port, the inner diameter of the pipe portion is expanded radially outward in a predetermined section of the tapered section that is in contact with the sealing portion.

9. In claim 1, A battery cell characterized in that the above welding part is positioned outside the above sealing part in the direction of the winding axis.

10. In claim 1, The above sealing member is a battery cell having a ball shape.

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

12. A method for manufacturing a battery cell according to any one of claims 1 to 11, A step of covering the open end with the lead while accommodating the electrode assembly in the can; A step of thermally bonding the edge of the lead to the can; A step of injecting an electrolyte into the can through the injection port of the lead connected to the can; A step of pressing the sealing member into the injection port after injecting the electrolyte to bring the injection port and the sealing member into close contact; and A method for manufacturing a battery cell, comprising: a step of welding the inner surface of the sealing member and the liquid injection port.

13. In claim 12, A battery cell manufacturing method, characterized in that the pressing load of the sealing member is 1 ton or less.

14. In claim 12, The sealing force of the above-mentioned injection port and the above-mentioned sealing member is 10 based on the He leak standard. -5 10 inland -3 A method for manufacturing a battery cell characterized by atm·cc / s.

15. A battery pack comprising a battery cell according to any one of claims 1 to 11.

16. A vehicle equipped with the battery pack of claim 15.

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