Battery cell, manufacturing method of same, and battery pack and vehicle including same

Abstract

A battery cell of the present invention may comprise: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound with respect to a winding axis; a battery housing configured to accommodate the electrode assembly via an open end formed at one side thereof; a cap covering the open end and having an injection hole formed at the center thereof; an injection plug configured to be inserted into the injection hole and configured to seal the injection hole; and a gasket interposed between the injection plug and the cap and having chemical resistance to an electrolyte.

Description

Battery cell, method of manufacturing the same, and battery pack including the battery cell and automobile

[0001] The present invention relates to a battery cell, a method for manufacturing the same, a battery pack including the battery cell, and an automobile.

[0002] This application is a priority application for Korean Patent Application No. 10-2024-0131037 filed on September 26, 2024, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference.

[0003]

[0004] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product categories, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric sources.

[0005] These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency, not only for the primary advantage of being able to drastically reduce the use of fossil fuels, but also because they do not generate any by-products from the use of energy.

[0006] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. When a high output voltage is required, multiple battery cells are connected in series to form a battery module or battery pack. Additionally, to increase charge / discharge capacity, multiple battery cells are connected in parallel to form a battery module or battery pack. Therefore, the number of battery cells included in the above battery module or pack can be set in various ways depending on the required output voltage or charge / discharge capacity.

[0007] There is increasing demand for metal can-type cells as battery cells for automotive battery packs. Metal cans can be prismatic or cylindrical; cylindrical battery cells feature a structure that accommodates a jelly-roll type electrode assembly inside a cylindrical can, offering the advantage of being more robust against shock and temperature than pouch-type battery cells.

[0008] The process of manufacturing a battery cell using a cylindrical can may include the steps of manufacturing a can by deep drawing a metal sheet to form a circular bottom (closed surface) and a circular tubular side wall connected thereto, accommodating an electrode assembly inside the can, and then finishing by covering the open end of the can with a cap. Seam welding or beading and crimping methods may be used for the finishing.

[0009] Meanwhile, in the case of battery cells including such a beading crimping structure, there was a problem in that the energy density decreased due to an increase in dead space within the cell along the winding axis.

[0010] Seam welding is a method in which the leading edge of the battery housing's sidewall is butted against the edge of the cap and welded along the circumference. Because the fixing structure is simple, it allows for a larger volume of electrode assembly to be accommodated inside the battery housing. Therefore, the seam welding method is more advantageous for securing electrical capacity relative to the same volume of the battery housing. However, since it is difficult to weld after injecting the fluid, an injection port must be provided in the cap, and a process of injecting fluid after welding and sealing the port with a sealing component is required.

[0011] Specifically, when fixing the open end of a battery housing and a cap by seam welding, a method may be applied in which a battery housing or a cap having an injection port provided at the bottom is prepared, an electrode assembly is accommodated inside the battery housing, the battery housing and the cap are seam welded, an electrolyte is injected through the injection port provided at the bottom of the cap or battery housing, and after the injection is completed, the injection port is sealed. Seam welding or ball welding may be used for the sealing method.

[0012] In the case of ball welding, welding (e.g., laser welding) can be performed after ball insertion. However, since the welding between the ball and the cap is not a typical butt weld but involves a gap, adhesion is reduced and crack formation may occur easily. If such microcracks occur, a sealed structure cannot be formed. Furthermore, during the battery utilization process, a voltage drop may occur, leading to the cell being classified as defective. Moreover, a thin cap acts as a constraint that prevents sufficient pressure from being applied to the ball, which may result in a risk of electrolyte leakage. Additionally, residual electrolyte may remain around the injection port, affecting weldability. Furthermore, during laser welding, pores may form in the weld area depending on keyhole maintenance and the condition of the weld surface, which can cause leakage.

[0013] Therefore, to increase repeatability and reproducibility, it is necessary to form a sealed injection port structure using mechanical joining rather than welding.

[0014]

[0015] The present invention is designed to solve problems such as those described above, and the objective of the present invention is to provide a battery cell with an improved sealing structure of the injection port and a method for manufacturing the same.

[0016] In addition, the problem that the present invention aims to solve is to provide a liquid injection port sealing structure and a method for manufacturing the same that can minimize crack formation during the sealing process of the liquid injection port, prevent electrolyte leakage, and increase repeatability and reproducibility.

[0017] In addition, the present invention has the objective of increasing energy density by excluding a beading clamping structure from a battery cell.

[0018] Another problem that the present invention aims to solve is to provide a vehicle including such a battery pack.

[0019] However, the problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art from the description of the invention below.

[0020]

[0021] To solve the above problem, the battery cell of the present invention may include an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound along a winding axis; a battery housing configured to accommodate the electrode assembly through an open end formed on one side; a cap covering the open end and having a liquid injection port formed in the center; a liquid injection plug configured to be inserted into the liquid injection port and configured to seal the liquid injection port; and a gasket interposed between the liquid injection plug and the cap and having chemical resistance to an electrolyte.

[0022] The above gasket may be characterized by having a heat deformation temperature of 130 degrees or more and 170 degrees or less at a load of 66 psi.

[0023] The above gasket may be characterized by having a moisture absorption rate of 0.05% or more and 0.15% or less.

[0024] The above gasket may be characterized by having a tensile strength of 50 MPa or more and 70 MPa or less.

[0025] The above gasket may be characterized by including polybutylene terephthalate (PBT).

[0026] The above injection stopper may be characterized by being composed of a blind rivet.

[0027] The above-described liquid injection stopper may be characterized by comprising a main body portion inserted into the liquid injection port, a flange portion covering the liquid injection port on the upper side of the cap and extending outward in a radial direction perpendicular to the winding axis direction from the upper end of the main body portion, and a plastic deformation portion at least partially extending outward in the radial direction from the lower end of the main body portion.

[0028] The diameter of the above flange portion may be larger than the inner diameter of the above injection port.

[0029] The maximum diameter of the above plastic deformation part may be characterized as being larger than the inner diameter of the above injection port.

[0030] At least a portion of the plastic deformation portion may be characterized by including a horizontal plane substantially parallel to the lower surface of the cap.

[0031] The above injection stopper may be characterized by having a mandrel hole formed extending from the upper surface of the injection stopper in the direction of the winding axis.

[0032] The above injection stopper may be characterized by further including a mandrel piece disposed inside the above injection stopper.

[0033] The above-mentioned liquid stopper may be characterized by including a material having elongation.

[0034] The above gasket may be characterized as having a ring shape that surrounds the periphery of the injection port.

[0035] The above gasket may be characterized by being positioned between the upper surface of the cap and the lower surface of the flange portion of the liquid injection stopper.

[0036] The above gasket may be characterized by having a circular cross-section cut along the direction of the winding axis centered on the winding axis.

[0037] The above gasket may be characterized by having a rectangular cross-section cut along the direction of the winding axis centered on the winding axis.

[0038] The above gasket may be characterized by having a cylindrical structure that wraps around the sides of the main body and the plastic deformation part, with both sides facing the winding axis open.

[0039] The above gasket may be characterized by including a curved surface and having at least a portion protruding in the radial direction.

[0040] The above gasket may be characterized by having an elongation rate of 40% or more and 150% or less.

[0041] The above gasket may be characterized by having a flexural modulus of 300 MPa or more and 2500 MPa or less.

[0042] The battery cell manufacturing method of the present invention may be characterized by comprising: a first step of inserting an electrode assembly, in which a first electrode, a second electrode, and a separator interposed between them are wound along a winding axis, through an open end of a battery housing; a second step of covering the open end of the battery housing with a cap; a third step of inserting a liquid injection plug preform into a liquid injection port formed in the cap; a fourth step of inserting a gasket between the liquid injection plug preform and the cap; and a fifth step of connecting a riveting gun to a mandrel inserted into the liquid injection plug preform and pulling the riveting gun upward to seal the liquid injection port.

[0043] When the above riveting gun is pulled upward, the above injection plug preform may be characterized by plastic deformation.

[0044] The above injection stopper preform may be characterized by having a mandrel hole formed extending in the direction of the winding axis, and configured to allow a mandrel to be inserted into the mandrel hole.

[0045] The above mandrel may be characterized by including a mandrel pin portion in which at least a portion protrudes outwardly from the injection plug preform, a mandrel head portion extending radially outwardly from the lower end of the mandrel pin portion than the mandrel pin portion, and a weak portion located between the mandrel pin portion and the mandrel head portion.

[0046] The above mandrel hole may be characterized by having a first region having a first length of inner diameter and a second region located below the first region having a second length of inner diameter longer than the first length.

[0047] The diameter of the above mandrel head portion may be longer than the above first length.

[0048] When the above mandrel is pulled upward, the length in the winding axis direction of the above injection plug preform is reduced, and the maximum diameter of the above injection plug preform is extended to be longer than the inner diameter of the above injection port.

[0049] The above mandrel may be characterized by containing iron (Fe).

[0050] When the above mandrel is pulled upward, the gasket is compressed in the direction of the winding axis, and the length of the gasket in the direction of the winding axis may be reduced.

[0051] When the above mandrel is pulled upward, the mandrel pin portion and the mandrel head portion may be characterized as being separated from the above vulnerable portion when a force greater than a certain amount is applied.

[0052] Between the second step and the third step, the method may further include a step of injecting an electrolyte into the injection port, a pre-charge step of partially charging the battery cell to activate the battery cell, an activation step of charging the battery cell to a higher voltage, and a degassing step of removing gas generated inside the battery cell.

[0053] In addition, the present invention can provide a battery pack comprising at least one battery cell according to the present invention.

[0054] In addition, the present invention can provide an automobile comprising at least one battery cell according to the present invention.

[0055]

[0056] According to one aspect of the present invention, by using a liquid injection plug composed of a blind rivet, the liquid injection port can be sealed through a mechanical connection such as riveting, thereby improving the liquid injection port sealing structure so as not to require welding.

[0057] In addition, according to another aspect of the present invention, a gasket is provided between the injection stopper and the cap to prevent leakage of the electrolyte and to electrically insulate the injection stopper and the cap.

[0058] In addition, according to another aspect of the present invention, by including a gasket having chemical resistance to the electrolyte, the sealing structure inside the battery housing can be further strengthened and electrolyte leakage can be prevented more reliably.

[0059] In addition, according to another aspect of the present invention, energy density can be increased by excluding a beading clamping structure from a battery cell.

[0060] In addition, according to another aspect of the present invention, the injection port can be sealed after degassing following the activation process, thereby preventing gas that was not completely removed from increasing the internal pressure of the battery cell and causing safety problems.

[0061] In addition, according to another aspect of the present invention, events resulting from thermal runaway phenomena in a vehicle comprising a plurality of battery packs, such as fire or explosion, can be prevented or delayed.

[0062] In addition to the above, the present invention may have various other effects, which are described in each embodiment, or effects that can be easily inferred by those skilled in the art, etc., will be omitted.

[0063]

[0064] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0065] FIG. 1 is a perspective view showing the appearance of a battery cell according to one embodiment of the present invention.

[0066] FIG. 2 is an exploded perspective view of FIG. 1 according to one embodiment of the present invention.

[0067] FIG. 3 is a cross-sectional view taken along A-A' of the battery cell of FIG. 1 according to one embodiment of the present invention.

[0068] Figure 4 is a cross-sectional perspective view of the battery cell of Figure 1 cut along A-A'.

[0069] Figure 5 is an enlarged view of part B of Figure 4.

[0070] FIG. 6 is a cross-sectional view of a cap, an injection stopper, and a gasket according to one embodiment of the present invention.

[0071] FIG. 7 is a cross-sectional view showing a cap, a liquid injection stopper, and a gasket separated according to one embodiment of the present invention.

[0072] FIG. 8 is a cross-sectional view of a cap, a liquid injection stopper, and a gasket according to another embodiment of the present invention.

[0073] FIG. 9 is a cross-sectional view of a cap, an injection stopper, and a gasket according to another embodiment of the present invention.

[0074] FIG. 10 is a cross-sectional view of a cap, an injection stopper, and a gasket according to another embodiment of the present invention.

[0075] FIG. 11 is a cross-sectional view of a cap, an injection stopper, and a gasket according to another embodiment of the present invention.

[0076] FIG. 12 is a drawing showing a liquid injection plug preform and a gasket before riveting according to one embodiment of the present invention.

[0077] FIG. 13 is a drawing showing a liquid injection plug preform and a gasket before riveting according to an embodiment of FIG. 11 of the present invention.

[0078] FIG. 14 is a cross-sectional view showing the injection plug preform and gasket separated before riveting according to one embodiment of the present invention.

[0079] FIG. 15 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0080] FIG. 16 is a drawing for explaining a vehicle including the battery pack of FIG. 15.

[0081]

[0082] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0083] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0084] In addition, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar configurations are omitted, and the focus is on the differences.

[0085] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0086] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0087] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0088] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0089] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0090] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0091] Meanwhile, although terms indicating directions such as up, down, left, right, front, and back may be used in this specification, these terms are used merely for convenience of explanation and may vary depending on the position or arrangement, rotation, or position of the observer, as is obvious to those skilled in the art of this invention.

[0092] For convenience of explanation, in this specification, the direction following the length direction of the winding axis of an electrode assembly wound in a jelly roll shape is referred to as the winding axis direction. The direction surrounding the winding axis is referred to as the circumferential direction or perimeter direction. Furthermore, the direction approaching or moving away from the winding axis is referred to as the radial direction. In particular, the direction approaching the winding axis is referred to as the centripetal direction, and the direction moving away from the winding axis is referred to as the centrifugal direction.

[0093] FIG. 1 is a perspective view showing the exterior of a battery cell (10) according to one embodiment of the present invention. FIG. 2 is an exploded perspective view of FIG. 1 according to one embodiment of the present invention. FIG. 3 is a cross-sectional view of the battery cell (10) of FIG. 1 cut along A-A' according to one embodiment of the present invention.

[0094] Referring to FIGS. 1 to 3, a battery cell (10) according to one embodiment of the present invention may include an electrode assembly (100), a battery housing (200), a cap (300), a liquid injection cap (400), and a gasket (500).

[0095] Referring to FIG. 3, the electrode assembly (100) may have a first unwound portion (110) and a second unwound portion (120). More specifically, the electrode assembly (100) may be in the form of a jelly-roll wound around a winding axis with a first electrode and a second electrode interposed between them. Here, the first electrode and the second electrode may be formed in a sheet shape. An additional separator may be provided on the outer surface of the electrode assembly (100) for insulation from the battery housing (200). The structure of the electrode assembly (100) is not limited by the embodiment and may have a winding structure well known in the art.

[0096] The first electrode may be a negative electrode plate and the second electrode may be a positive electrode plate. A negative electrode active material may be coated on one or both sides of the negative electrode plate, and a first uncoated portion (110) in which the negative electrode active material is not coated may be formed at the end of the negative electrode plate. The first uncoated portion (110) may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (100) and may be used as an electrode tab itself. A positive electrode active material may be coated on one or both sides of the positive electrode plate, and a second uncoated portion (120) in which the positive electrode active material is not coated may be formed at the end of the positive electrode plate. The second uncoated portion (120) may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (100) and may be used as an electrode tab itself. That is, the positive electrode plate and the negative electrode plate may each include an uncoated portion in which the active material is not coated at the end of the long side in the winding direction. Additionally, the first non-reinforced portion (110) and the second non-reinforced portion (120) may be configured to face in opposite directions. The first non-reinforced portion (110) may be housed inside the battery housing (200) so as to be located at one end in the direction of the winding axis, and the second non-reinforced portion (120) may be located at the other end in the direction of the winding axis. Here, the positive active material coated on the positive plate and the negative active material coated on the negative plate may be used without limitation as long as they are active materials known in the art.

[0097] In addition, the separator may be a porous polymer film, such as a polyolefin-based polymer like ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc., used alone or in a laminated form. As another example, the separator may be a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0098] At least one surface of the separation membrane may include a coating layer of inorganic particles. It is also possible for the separation membrane itself to consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure bonded with a binder such that interstitial volume exists between adjacent particles.

[0099] For example, notches may be formed at a predetermined interval in the first blank section (110) and the second blank section (120) to form flag-shaped notching tabs. In the jelly-roll type electrode assembly (100), the notching tabs may be folded radially and flattened. The notching tabs may be folded radially inward or outward. The notching tabs may be folded one by one during the process of winding the laminate to form the jelly-roll type electrode assembly (100). Alternatively, the notching tabs may be folded all at once after winding the laminate to form the jelly-roll type electrode assembly (100). The notching tabs of the first blank section (110) and the notching tabs of the second blank section (120), which are folded radially and overlapped in this way, may each provide a plane that is substantially perpendicular to the axial direction at both axial ends of the electrode assembly (100).

[0100] Referring to FIGS. 1 to 3, a battery housing (200) may be configured to accommodate an electrode assembly (100). The battery housing (200) may have an open end formed on one side. The battery housing (200) may be a roughly cylindrical receptacle with an open end formed on one side. For example, the electrode assembly (100) may be accommodated inside the battery housing (200) such that the first non-receptor portion (110) faces the open end. Specifically, the battery housing (200) may include a side wall portion, a bottom portion connected to one axial end of the side wall portion, and an open end provided at the other axial end of the side wall portion. The side wall portion and the bottom portion of the battery housing (200) may be formed integrally. The bottom portion has a roughly flat shape. The side wall portion may be cylindrical, connected to the bottom portion, and may extend axially. The side wall portion that is not connected to the bottom portion can be defined as the open end of the battery housing (200). In FIGS. 1 to 3, the bottom portion is shown as being included at the bottom of the battery housing (200), and the open end is shown as being included at the top of the battery housing (200). The open end may be formed in a portion facing the bottom portion of the battery housing (200). Accordingly, the electrode assembly (100) can be accommodated through the open end formed in the battery housing (200).

[0101] The side wall portion of the battery housing (200) may be configured to have a cylindrical shape with a constant radius. Preferably, the entire area of ​​the side wall portion of the battery housing (200) may be configured to have a cylindrical shape with a constant radius.

[0102] According to one embodiment, the bottom portion forms a closed surface of the battery housing (200), and a through hole is formed in the bottom portion, and an electrode terminal (210) can pass through the through hole.

[0103] Conventional battery housings (200) may further include a beading portion formed at an end adjacent to an open end and a clamping portion formed on the beading portion, but the battery housing (200) of the present invention may not have a beading clamping structure formed on the side wall portion. That is, the battery housing (200) of the present invention may not have the side wall portion inserted inward. That is, the battery housing (200) of the present invention may be configured to have a constant radius over the entire area of ​​the side wall portion.

[0104] According to this structure, by excluding the beading and crimping structure from the cylindrical battery cell (10), various process errors that may occur due to the beading and crimping structure can be prevented. In addition, process simplification can be achieved by omitting processes such as beading and crimping. Furthermore, the phenomenon in which the dead space within the battery increases and the energy density decreases in the direction of the winding axis of the electrode assembly (100) due to the formation of the beading and crimping structure can be prevented. Therefore, the battery cell (10) according to the present invention can increase the internal capacity more than a battery cell using the beading and crimping method with the same external shape. That is, according to the structure of the present invention, the energy density of the battery cell (10) can be improved.

[0105] The battery housing (200) may include a conductive metal material. The material of the battery housing (200) may include a conductive metal, such as aluminum, steel, stainless steel, etc. For example, the bottom portion and the side wall portion may be manufactured by forming a metal sheet, on which nickel is plated on the surface of steel, using a deep drawing process, and then trimming the leading edge of the side wall portion with a punch while holding it with a blank holder. However, the material and manufacturing method of the battery housing (200) are not limited thereto.

[0106] The battery housing (200) can be electrically connected to the first non-electrode portion (110) of the electrode assembly (100). Accordingly, the battery housing (200) can have a first polarity.

[0107] Referring to FIGS. 1 to 3, the cap (300) may be configured to cover an open end formed on one side of the battery housing (200). The cap (300) may be configured to have, for example, a roughly plate shape. The cap (300) may be coupled to the open end of the battery housing (200). For example, the cap (300) may be seated on the upper edge of the open end of the battery housing (200). Or, for example, as shown in FIG. 3, the cap (300) may be in contact with the inner surface of the upper edge of the open end of the battery housing (200).

[0108] The open end of the battery housing (200) and the contact point of the cap (300) can be joined. For example, the joining point between the open end of the battery housing (200) and the cap (300) can be joined by welding. For example, the cap (300) can be joined to the battery housing (200) using butt welding. Thus, the battery cell (10) can have a larger internal capacity in the same external shape than a battery cell using beading and crimping methods. Thus, the energy density of the battery cell (10) can be increased. However, the battery housing (200) and the cap (300) can be joined by other joining methods other than welding, and the joining method is not limited to this. By joining the battery housing (200) and the cap (300), the battery cell (10) can be sealed.

[0109] The cap (300) may be made of a metal material. Therefore, the cap (300) may be conductive. For example, the cap (300) may include an aluminum material. The cap (300) may be electrically connected to the battery housing (200). Meanwhile, since the battery housing (200) is also made of a conductive metal, the cap (300) combined with the battery housing (200) may be configured to have the same polarity as the battery housing (200). For example, the cap (300) may be configured to have a first polarity.

[0110] The thickness of the cap (300) may be approximately 0.5 mm or more and 2 mm or less. For example, the thickness of the cap (300) may be approximately 1 mm.

[0111] A liquid injection port (H1) may be formed in at least a portion of the cap (300). A liquid injection port (H1) may be formed in the center of the cap (300). At this time, the liquid injection port (H1) may be blocked by a liquid injection stopper (400) to be described later. For example, the liquid injection stopper (400) may be pressed onto the liquid injection port (H1). By blocking the liquid injection port (H1) with the liquid injection stopper (400), the battery cell (10) can be sealed.

[0112] The injection port (H1) can serve as, for example, an electrolyte injection port. The center of the injection port (H1) may coincide with the center of the winding center hole (H) of the electrode assembly (100). That is, the injection port (H1) of the cap (300) may be located above the winding center hole (H) of the electrode assembly (100) in the direction of the winding axis.

[0113] The diameter of the injection port (H1) can be formed to be smaller than the diameter of the winding center hole (H) of the electrode assembly (100). For example, the diameter of the injection port (H1) can be approximately 3 mm or more and 4 mm or less. According to this structure, the injection plug (400) moves downward during the process of being pressed into the injection port (H1). At this time, damage to the electrode assembly (100) or the first current collector plate (130) coupled to the electrode assembly (100) can be prevented by the injection plug (400) that has moved downward. That is, even if the injection plug (400) is pressed downward, the injection plug (400) is formed to enter the interior of the winding center hole (H) of the electrode assembly (100), so it can not affect the folded surface of the electrode assembly (100) or the electrode tab.

[0114] Meanwhile, the injection port (H1) can be configured to discharge gas generated during the pre-charge process described later. That is, after a degassing process in which all gases generated during the pre-charge process are discharged through the injection port (H1), the injection cap (400) can be configured to be attached to the injection port (H1). Accordingly, the swelling phenomenon of the battery cell (10) can be reduced.

[0115] Referring to FIG. 3, the cap (300) may be provided with a vent portion (V). Since the vent portion (V) is provided in the cap (300) and does not occupy a separate space, energy density can be further secured. The vent portion (V) may rupture when the pressure inside the battery housing (200) exceeds a critical threshold. The vent portion (V) may be formed on one or both sides of the cap (300). The vent portion (V) may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the cap (300). For example, the vent portion (V) may be formed in the shape of a roughly circular ring having a certain width. This circular ring-shaped vent portion (V) may have the same center as the center of the cap (300). For example, the vent portion (V) may be implemented as a thin-walled section with notched processing on both surfaces of the cap (300).

[0116] Referring to FIGS. 1 to 3, the injection plug (400) may be configured to seal the injection port (H1). That is, the injection plug (400) may be configured to be inserted into the injection port (H1). The injection plug (400) may penetrate the injection port (H1). By inserting the injection plug (400) into the injection port (H1) of the cap (300), the sealing of the battery cell (10) can be ensured. The injection plug (400) penetrates the injection port (H1) formed in the cap (300) to seal the outside and inside of the battery housing (200) and prevent leakage of the electrolyte.

[0117] According to such a structure, the beading and crimping processes can be omitted, thereby enabling process simplification. Furthermore, due to the beading and crimping structure, the phenomenon in which the energy density decreases due to an increase in dead space within the battery in the winding axis direction of the electrode assembly (100) can be prevented. In other words, according to a structure like the present invention, the energy density of the battery cell (10) can be improved.

[0118] The injection stopper (400) may be constructed with a blind rivet. Here, that is, the injection stopper (400) may be joined to the cap (300) through a blind rivet riveting method. The injection stopper (400) may be secured to the cap (300) by riveting.

[0119] Conventionally, a ball was pressed and welded to seal the injection port (H1). When welding the ball and the cap (300), since it is not a standard butt weld, micro-cracks can easily form between the ball and the cap (300). Furthermore, if such cracks are formed, the cell may be determined as defective due to voltage drop issues during the battery utilization process. Additionally, considering the thickness of the cap (300), there is a limit to the pressing force of the ball, so the electrolyte may easily leak.

[0120] The liquid stopper (400) composed of blind rivets may have high durability or rigidity. The liquid stopper (400) composed of blind rivets may not be damaged even if internal pressure rises due to a short circuit or other factors occurring inside the battery housing (200). When the vent pressure was tested under conditions of 25 bar, the vent portion (V) of the cap (300) was broken, but the liquid stopper (400) composed of blind rivets was not damaged, confirming that the liquid stopper (400) is strong against vent pressure.

[0121] According to an embodiment of the present invention, the injection stopper (400) is configured with a blind rivet to improve sealing power and prevent leakage of the electrolyte. Additionally, by sealing with a mechanical connection such as riveting, the sealing step can be performed repeatedly, and the repeatability and reproducibility of the sealing step can be increased.

[0122] The battery cell (10) may further include a first current collector plate (130) configured to be electrically connected to a first electrode and a second current collector plate (140) configured to be electrically connected to a second electrode. The first current collector plate (130) and the second current collector plate (140) may each be joined to a substantially flat surface provided by bending notching tabs exposed at both ends in the winding axis direction of the electrode assembly (100). A method such as resistance welding, ultrasonic welding, or laser welding may be used for joining.

[0123] The battery housing (200) can be electrically connected to the first current collector plate (130). The electrode terminal (210) can be electrically connected to the second current collector plate (140). Accordingly, the battery housing (200) may have a first polarity, and the electrode terminal (210) may have a second polarity. That is, the electrode terminal (210) may refer to an electrode terminal (210) having a second polarity. In particular, the bottom portion of the battery housing (200), the side wall portion connected thereto, and the cap (300) may all have a first polarity. Accordingly, both the first polarity and the second polarity may be formed on the bottom portion of the battery housing (200). Then, the battery housing (200) may have a busbar connected to the electrode terminal (220) having a first polarity and a busbar connected to the electrode terminal (210) having a second polarity, both located at one end of the battery housing (200) in the direction of the winding axis. In one example, the electrode terminal (220) having a first polarity may be a negative terminal, and the electrode terminal (210) having a second polarity may be a positive terminal. Of course, the opposite may also be true. Accordingly, the battery cell (10) according to the present invention can simplify the electrical connection structure by allowing both the positive and negative electrodes to be connected in one direction when electrically connecting a plurality of battery cells (10). In addition, the battery cell (10) according to the present invention has the advantage of being able to secure a sufficient area for welding components for electrical connection, as most of the bottom portion of the battery housing (200) can be used as the electrode terminal (220) having a first polarity.

[0124] The battery cell (10) may further include an insulator (150). The insulator (150) may be provided between the second collector plate (140) and the inner surface of the bottom portion. The insulator (150) prevents contact between the second collector plate (140) and the battery housing (200). The insulator (150) may also be interposed between the inner surface of the side wall portion and the electrode assembly (100). That is, the insulator (150) may also be interposed between the second non-removable portion (120) and the battery housing (200). This is to prevent contact between the second non-removable portion (120), which extends toward the bottom portion of the battery housing (200), and the inner surface of the battery housing (200).

[0125] Preferably, the battery cell (10) may be a cylindrical secondary battery, for example, having a form factor ratio (ratio of height to diameter) greater than approximately 0.4. Preferably, the diameter of the battery cell (10) may be 40 mm to 50 mm, and the height may be 60 mm to 130 mm. The form factor of the battery cell (10) may be, for example, 46110, 4875, 48110, 4880, or 4680.

[0126] However, the shape of the battery cell (10) according to the present invention is not limited by the above and can be applied to batteries of other shapes. For example, it can be applied to prismatic batteries.

[0127] FIG. 4 is a cross-sectional view of the battery cell of FIG. 1 along A-A'. FIG. 5 is an enlarged view of section B of FIG. 4. FIG. 6 is a cross-sectional view of a cap, a liquid injection stopper, and a gasket according to an embodiment of the present invention. FIG. 7 is a cross-sectional view showing the cap, a liquid injection stopper, and a gasket separated according to an embodiment of the present invention.

[0128] The injection stopper (400) may be configured to surround the injection port periphery (310) of the cap (300) on at least three sides. The injection stopper (400) may surround the upper surface (311), lower surface (312), and inner surface (313) of the injection port periphery (310) of the cap (300). Accordingly, the sealing force may be improved.

[0129] A portion of the liquid injection cap (400) is inserted inside the battery housing (200), and another portion may be exposed outside the battery housing (200). A portion of the liquid injection cap (400) may be located on the upper side of the cap (300) with respect to the winding axis direction, and another portion may be located on the lower side of the cap (300).

[0130] The injection plug (400) may include a main body (410) inserted into the injection port (H1), a flange (420) extending radially outward from the upper end of the main body (410) in a direction perpendicular to the winding axis, and a plastic deformation part (430) extending radially outward from at least a portion of the lower end of the main body (410).

[0131] The main body (410) may be a portion that extends axially to penetrate the injection port (H1). The main body (410) may penetrate the battery housing (200). At least a portion of the main body (410) may be located inside the battery housing (200). The side of the main body (410) may be surrounded by the injection port periphery (310) of the cap (300). The main body (410) may be cylindrical in shape. Referring to FIG. 6, the diameter (d1) of the main body (410) may be substantially similar to or smaller than the inner diameter (r1) of the injection port (H1). The diameter (d1) of the main body (410) may be substantially the same as the inner diameter (r1) of the injection port (H1).

[0132] The flange portion (420) can cover the injection port (H1) on the upper side of the cap (300). The flange portion (420) can be located on the outside of the battery housing (200). The diameter (d2) of the flange portion (420) may be larger than the diameter (d1) of the main body portion (410). The diameter (d2) of the flange portion (420) may be larger than the inner diameter (r1) of the injection port (H1). According to the above embodiment of the present invention, even under external pressure, the injection plug (400) does not fall into the winding center hole (H) of the electrode assembly (100), its position can be fixed, and the injection port (H1) can be easily sealed.

[0133] According to one embodiment, the thickness of the flange portion (420) may be constant in the radial direction. For example, the flange portion (420) may include a flat surface. According to another embodiment, although not shown in the drawing, the flange portion (420) may be formed such that its thickness increases towards the inner side in the radial direction. For example, the cross-section of the flange portion (420) cut in the direction of the winding axis with respect to the winding axis may be hemispherical. However, the shape of the flange portion (420) is not limited by the above embodiment and may be designed in various ways.

[0134] The plastic deformation portion (430) may be a part whose shape is deformed by receiving external pressure (tension) through riveting. The plastic deformation portion (430) may be formed by plastically processing a part protruding inwardly from the cap (300). According to one embodiment, the thickness of the plastic deformation portion (430) may be constant in the radial direction. The side of the plastic deformation portion (430) may have an irregular shape. For example, the plastic deformation portion (430) may include a curved surface formed in the vertical direction. That is, the side of the plastic deformation portion (430) of the present invention may be configured to have a non-uniform radius over the entire area.

[0135] The maximum diameter (d1') of the plastic deformation portion (430) may be larger than the inner diameter (r1) of the injection port (H1). According to the above embodiment of the present invention, since the diameters of the flange portion (420) located on the upper side of the cap (300) and the plastic deformation portion (430) located on the lower side of the cap (300) are both larger than the inner diameter (r1) of the injection port (H1), the injection plug (400) does not move upward or downward and can be fixed in position. Therefore, the injection port (H1) can be strongly sealed to seal the inside and outside of the battery housing (200) and prevent leakage of the electrolyte.

[0136] According to one embodiment, at least a portion of the plastic deformation portion (430) may include a horizontal plane (P) substantially parallel to the lower surface of the cap (300). The horizontal plane (P) may be a portion extending radially in a vertical direction from the lower end of the main body portion (410). The horizontal plane (P) may face the lower surface (312) of the cap (300). According to the above embodiment of the present invention, the horizontal plane (P) of the plastic deformation portion (430) is configured to face the cap (300), so that the cap (300) can be more closely attached to the plastic deformation portion (430) of the liquid injection stopper (400). Accordingly, the sealing force of the liquid injection stopper (400) may be increased.

[0137] A mandrel hole (H2) may be formed in the liquid injection plug (400) and extend in the direction of the winding axis from the upper surface of the liquid injection plug (400). The mandrel hole (H2) may be formed to penetrate the center of the liquid injection plug (400). The mandrel hole (H2) may penetrate the center of the flange portion (420) and the main body portion (410) of the liquid injection plug (400). A portion of the mandrel hole (H2) may be located at least in the upper portion of the plastic deformation portion (430) of the liquid injection plug (400). The mandrel hole (H2) may be a hole into which a mandrel (60 in FIG. 12) to be described later is inserted or removed. The inner diameter (r2) of the mandrel hole (H2) may be larger than the diameter of the mandrel (60). The upper portion of the mandrel hole (H2) may be open, and the lower end of the mandrel hole (H2) may be sealed. The mandrel hole (H2) may be sealed in the plastic deformation portion (430) or the main body portion (410). A mandrel piece (440), which will be described later, may be located at the lower side of the mandrel hole (H2).

[0138] The liquid stopper (400) may further include a mandrel piece (440) disposed inside the liquid stopper (400). The mandrel piece (440) may be a part of a mandrel (60) inserted into a liquid stopper preform (see 40 in FIG. 12) before the liquid stopper (400) is plastically deformed and fixed to the cap (300). The mandrel piece (440) may have substantially the same configuration as the mandrel head portion (see 62 in FIG. 12) of the mandrel (60). During the process of riveting the liquid stopper preform (40), the mandrel (60) may be connected to a riveting gun (see G in FIG. 12) and pulled upward. At this time, if a force exceeding a certain level is applied, the mandrel head portion (62) and the mandrel pin portion (see 61 in FIG. 12) constituting the mandrel (60) may be separated. At this time, the mandrel head part (62) that is separated and embedded in the injection plug (400) can be defined as a mandrel piece (440).

[0139] Referring to FIG. 6, the diameter (d4) of the mandrel piece (440) may be larger than the inner diameter (r2) of the mandrel hole (H2). That is, the mandrel piece (440) may protrude radially outward from the inner surface of the injection plug (400) surrounding the mandrel hole (H2). According to the above embodiment of the present invention, when the force pulling the mandrel head part (62) upward exceeds the yield point of the injection plug (400) material, at least a portion of the injection plug preform (40) may be plastically deformed.

[0140] The liquid injection stopper (400) may include aluminum. Since the liquid injection stopper (400) is susceptible to corrosion from the electrolyte, it may include a corrosion-resistant material. The liquid injection stopper (400) may include a material having elongation. According to the above embodiment of the present invention, when a force greater than a predetermined amount is applied to the liquid injection stopper preform (40), its shape may be deformed. Accordingly, at least a portion of the liquid injection stopper preform (40) may be plastically deformed to seal the liquid injection port (H1).

[0141] The process of sealing the injection port (H1) through the injection stopper (400) will be described later.

[0142] Referring to FIGS. 4 to 6, a gasket (500) may be interposed between a liquid injection plug (400) and a cap (300). Specifically, the gasket (500) may be positioned between the upper surface (311) of the cap (300) and the lower surface of the flange portion (420) of the liquid injection plug (400). That is, the liquid injection plug (400) may be riveted to the cap (300) with the gasket (500) interposed therein. For example, the gasket (500) may be positioned parallel to the lower surface of the flange portion (420) and the upper surface (311) of the cap (300).

[0143] The gasket (500) is interposed between the liquid injection plug (400) and the cap (300) to seal the inside and outside of the battery housing (200) to prevent leakage of the electrolyte and to electrically insulate the liquid injection plug (400) and the cap (300). The gasket (500) can be in close contact between the liquid injection plug (400) and the cap (300).

[0144] The gasket (500) may be in the shape of a ring that surrounds at least one surface of the liquid injection port periphery (310). The gasket (500) may be in the shape of a washer. According to one embodiment, the gasket (500) may be configured to be in contact with the upper surface of the liquid injection port periphery (310) of the cap (300) in the circumferential direction. Referring to FIG. 7, a gasket hole (H3) may be formed in the center of the gasket (500). The liquid injection plug (400) may be positioned to pass through the gasket hole (H3). Thus, it may be easy to seal the liquid injection port (H1) in the circumferential direction. Here, the gasket (500) may refer to an O-ring. According to the above embodiment of the present invention, the gasket (500) may be positioned on the outside of the battery housing (200) so that contact with the internal electrolyte may be difficult, and thus may be advantageous in terms of the chemical resistance of the gasket (500).

[0145] According to another embodiment, although not shown in the drawing, at least a portion of the gasket (500) may be inserted into the injection port (H1).

[0146] According to one embodiment, the gasket (500) may have a circular cross-section cut along the winding axis around the winding axis. The gasket (500) may be in a compressed state along the winding axis by riveting of the liquid injection stopper (400). For example, the gasket (500) may have an elliptical cross-section cut along the winding axis around the winding axis. For example, the radial diameter (o2) of the cross-section cut along the winding axis of the gasket (500) may be larger than the diameter (o1) in the winding axis direction. At this time, the diameter (o1) in the winding axis direction of the cross-section cut along the winding axis of the gasket (500) may be substantially the same as the vertical distance (g1) between the flange portion (420) and the cap (300).

[0147] The gasket (500) provided in the secondary battery may be required to have electrical insulation, elasticity, high heat resistance capable of maintaining airtightness under high temperature and high humidity conditions inside the battery, mechanical properties of durability, and chemical resistance to the electrolyte.

[0148] The gasket (500) may have chemical resistance to the electrolyte. A gasket (500) with high chemical resistance to the electrolyte can maintain the stability of the battery cell (10) and minimize damage even if the electrolyte leaks. The gasket (500) may have heat resistance and electrical insulation properties. Since the gasket (500) has excellent chemical resistance, it is resistant to corrosion, and since it has excellent heat resistance, its physical properties may not change significantly even when exposed to high temperatures.

[0149] For example, the gasket (500) may include a thermoplastic plastic. For example, the gasket (500) may include at least one of polyurethane (PU), polyethylene (PE), polycarbonate (PC), polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polyvinyl chloride (PVC), polybutylene terephthalate (hereinafter referred to as 'PBT'), polytetrafluoroethylene (PTFE), and perfluoroalkoxy (PFA).

[0150] For example, the gasket (500) may include at least one of PBT, PTFE, and PFA, which have excellent chemical resistance, heat resistance, and insulation properties. Since the gasket (500) has excellent chemical resistance, it is resistant to corrosion, and since it has excellent heat resistance, its physical properties may not change significantly even when exposed to high temperatures.

[0151] According to one embodiment, the gasket (500) may include PBT material. Since PBT material has excellent chemical resistance to electrolytes, it is resistant to corrosion and has excellent heat resistance. It also has a high heat distortion temperature, so its physical properties may not change significantly even when exposed to high temperatures. In addition, it has a low moisture absorption rate, so its physical properties can be maintained even when exposed to moisture. Furthermore, it has high tensile strength, so it can maintain mechanical strength even when subjected to external impacts or electrolytes. Therefore, the gasket (500) containing PBT material does not corrode for a long period, which may be advantageous in terms of battery stability. That is, the gasket (500) containing PBT material may be more suitable for electric vehicle batteries used for approximately 10 years or more. In addition, the gasket (500) containing PBT material is more cost-effective than other materials with chemical resistance and may be easy to mass-produce and manufacture.

[0152] The gasket (500) may have a heat deflection temperature (HDT) of 130 degrees or more and 170 degrees or less at a 66 psi load. The heat deflection temperature may refer to a characteristic indicating a critical point at which physical deformation begins depending on the temperature. Since the electrolyte is mostly used at high temperatures, the higher the heat deflection temperature (HDT) of the gasket (500), the more stable it may be. For example, the PBT gasket (500) may have a heat deflection temperature of 130 degrees or more and 170 degrees or less at a 66 psi load. For example, the PBT gasket (500) may have a heat deflection temperature of 140 degrees or more and 160 degrees or less at a 66 psi load. For example, the PBT gasket (500) may have a heat deflection temperature of 154 degrees at a 66 psi load. For example, the PBT gasket (500) may have a thermal deformation temperature of 40 degrees or more and 70 degrees or less at a load of 264 psi. For example, the PBT gasket (500) may have a thermal deformation temperature of 50 degrees or more and 60 degrees or less at a load of 264 psi. For example, the PBT gasket (500) may have a thermal deformation temperature of 54 degrees at a load of 264 psi. According to the battery cell (10) including the PBT gasket (500) of the present invention, it can withstand high temperatures without deformation, thus maintaining stable performance under high temperatures and various load conditions. In the present invention, the thermal deformation temperature required for the gasket is in accordance with the standards of the American Society for Testing Materials (ASTM).

[0153] The gasket (500) may have a water absorption rate of approximately 0.05% or more and 0.15% or less. Since the electrolyte may contain moisture, the water absorption rate of the gasket (500) may be an important characteristic for evaluating the chemical resistance of the gasket (500). That is, the lower the water absorption rate of the gasket (500), the higher the chemical resistance of the gasket (500). For example, the PBT gasket (500) may have a water absorption rate of approximately 0.05% or more and 0.15% or less. For example, the PBT gasket (500) may have a water absorption rate of approximately 0.07% or more and 0.12% or less. For example, the PBT gasket (500) may have a water absorption rate of approximately 0.08%. According to the battery cell (10) including the PBT gasket (500) of the present invention, it can maintain stable performance without corrosion even when exposed to the electrolyte for a long period of time. In the present invention, the moisture absorption rate required for the gasket is in accordance with the standards of the American Society for Testing Materials (ASTM).

[0154] The gasket (500) may have a tensile strength of approximately 50 MPa or more and 70 MPa or less. For example, the PBT gasket (500) may have a tensile strength of approximately 50 MPa or more and 70 MPa or less. For example, the PBT gasket (500) may have a tensile strength of approximately 55 MPa or more and 65 MPa or less. For example, the PBT gasket (500) may have a tensile strength of approximately 60 MPa. According to the battery cell (10) including the PBT gasket (500) of the present invention, since it has high tensile strength, it can maintain structural strength when exposed to an electrolyte and can exhibit strong resistance to external impacts, etc., thereby maintaining stable performance against physical impact. In the present invention, the tensile strength required for the gasket is in accordance with the standards of the American Society for Testing Materials (ASTM).

[0155] The gasket (500) may have an elongation of approximately 40% or more. For example, the elongation of the PBT gasket (500) may be approximately 40% or more and 150% or less. According to the above embodiment of the present invention, when the elongation satisfies the conditions of the above range, the battery stability against physical impact can be further improved by exhibiting sufficient mechanical strength required of the gasket (500). In the present invention, the elongation required of the gasket is in accordance with the standards of the American Society for Testing Materials (ASTM).

[0156] The flexural modulus of the gasket (500) may be approximately 300 MPa or more and 2500 MPa or less. The flexural modulus of the gasket (500) may be approximately 600 MPa or more and 2200 MPa or less. For example, the flexural modulus of the PBT gasket (500) may be approximately 1800 MPa or more and 2200 MPa or less. The flexural modulus of the PBT gasket (500) may be approximately 2000 MPa. According to the battery cell (10) including the PBT gasket (500) of the present invention, since it has a relatively high flexural modulus, it maintains airtightness within the battery cell (10) and exhibits a buffering effect against volume changes of the electrode assembly (100), thereby further improving battery stability against physical shocks, etc. In the present invention, the flexural modulus required for the gasket is in accordance with the standards of the American Society for Testing Materials (ASTM).

[0157] When applying a PBT gasket (500), the result of a He leak test at 70 degrees and 5 bar was that the amount of He leakage was 1.3 × 10⁻⁶ -6 It was measured at cc / sec, confirming excellent sealing power that easily passed the He leak test standard.

[0158] FIG. 8 is a cross-sectional view of a cap, a liquid injection stopper, and a gasket according to another embodiment of the present invention.

[0159] The flange portion (420) of the liquid injection cap (400) may include a protrusion (421) that protrudes in the lower direction of the winding axis direction. The protrusion (421) may be formed on the edge portion of the flange portion (420). The protrusion length of the protrusion (421) may be substantially equal to or smaller than the vertical distance (g1) between the lower surface of the flange portion (420) and the upper surface (311) of the cap (300). The protrusion length of the protrusion (421) may be smaller than the vertical distance (g1) between the lower surface of the flange portion (420) and the upper surface (311) of the cap (300).

[0160] The gasket (500) may be positioned between the protrusion (421) of the flange portion (420) and the main body portion (410). At least a portion of the gasket (500) may be surrounded by the protrusion (421) of the flange portion (420), the lower surface, and the main body portion (410).

[0161] According to the above embodiment of the present invention, the position of the gasket (500) can be easily fixed by the protrusion (421), and the gasket (500) can be compressed or the gasket (500) can not move in the horizontal direction due to external pressure. Therefore, the injection port (H1) can be sealed more securely, and leakage of the electrolyte can be further prevented.

[0162] FIG. 9 is a cross-sectional view of a cap, an injection stopper, and a gasket according to another embodiment of the present invention.

[0163] According to one embodiment, a gasket (e.g., 520 in FIG. 9) located on the lower surface of the cap may be further included. That is, the gasket (500) may have a first gasket (510) located on the upper surface of the cap and a second gasket (520) located on the lower surface of the cap. The first gasket (510) may have substantially the same configuration and shape as the gasket (500) described with reference to FIGS. 1 through 7. The second gasket (520) may have a different location from the first gasket (510) but may have substantially the same structure and shape.

[0164] The first gasket (510) and the second gasket (520) can simultaneously seal the upper surface (311) and the lower surface (312) of the cap (300). That is, the first gasket (510) and the second gasket (520) can simultaneously double-seal the inside and outside of the battery housing (200) to effectively prevent leakage of the electrolyte.

[0165] The second gasket (520) has a higher risk of exposure to the electrolyte than the first gasket (510), but since it uses a material with strong chemical and oil resistance, the risk of corrosion from the electrolyte can be minimized.

[0166] According to the above embodiment of the present invention, by providing a first gasket (510) and a second gasket (520), the assembly and connection of the gasket (500) can be facilitated, while the sealing power of the gasket (500) can be strengthened. In addition, the injection port (H1) can be sealed more securely, and leakage of the electrolyte can be further prevented.

[0167] FIG. 10 is a cross-sectional view of a cap, an injection stopper, and a gasket according to another embodiment of the present invention.

[0168] The gasket (500) may have a rectangular cross-section cut along the direction of the winding axis centered on the winding axis. The gasket (500) may be in a compressed state along the direction of the winding axis by riveting of the liquid injection plug (400). The inner surface of the gasket (500) may come into direct contact with the main body portion (410) of the liquid injection plug (400). The upper surface of the gasket (500) may come into direct contact with the flange portion (420) of the liquid injection plug (400). The lower surface of the gasket (500) may come into direct contact with the upper surface (311) of the cap (300).

[0169] According to the above embodiment of the present invention, the sealing performance can be further improved by ensuring that the gasket (500) completely seals the space between the cap (300) and the liquid stopper (400).

[0170] FIG. 11 is a cross-sectional view of a cap, an injection stopper, and a gasket according to another embodiment of the present invention.

[0171] The gasket (500) can cover the side of the liquid stopper (400). The gasket (500) can cover the side of the main body (410) and the plastic deformation part (430) of the liquid stopper (400). At least a portion of the gasket (500) can be positioned between the cap (300) and the liquid stopper (400) to seal the space between the cap (300) and the liquid stopper (400). For example, at least a portion of the gasket (500) can be positioned between the inner surface (313) of the cap (300) and the main body (410) of the liquid stopper (400). For example, at least a portion of the gasket (500) can be positioned between the lower surface (312) of the cap (300) and the plastic deformation part (430) of the liquid stopper (400). For example, at least a portion of the gasket (500) may be located between the lower surface (312) of the cap (300) and the horizontal plane (P) of the plastically deformed portion (430) of the injection stopper (400).

[0172] The gasket (500) may be a cylindrical structure with both sides open toward the winding axis. The gasket (500) may be a tubular structure with the upper and lower surfaces open. The shape of the gasket (500) may be substantially the same as the shape of the side of the main body (410) and the plastic deformation part (430) of the liquid injection stopper (400).

[0173] The gasket (500) includes a curved surface, and at least a portion may protrude radially. That is, the gasket (500) may have an irregular shape with an inconsistent radius. The portion of the gasket (500) facing the plastically deformed portion (430) of the injection plug (400) may protrude radially outward.

[0174] According to the above embodiment of the present invention, the gasket (500) seals the space between the side of the injection stopper (400) and the cap (300), thereby maximally blocking the exposure of the electrolyte between the injection stopper (400) and the cap (300), and preventing the electrolyte from adhering to the injection stopper (400) and being exposed between the cap (300) and the injection stopper (400). Accordingly, the sealing performance of the injection port (H1) can be further improved.

[0175] FIG. 12 is a drawing showing a liquid injection plug preform and gasket before riveting according to an embodiment of the present invention. FIG. 13 is a drawing showing a liquid injection plug preform and gasket before riveting according to an embodiment of FIG. 11 of the present invention. FIG. 14 is a cross-sectional view showing a liquid injection plug preform and gasket before riveting separated according to an embodiment of the present invention.

[0176] Hereinafter, the method for manufacturing a battery cell (10) described with reference to FIGS. 1 to 11 will be described with reference to FIGS. 12 to 14.

[0177] A method for manufacturing a battery cell (10) may include a first step of inserting an electrode assembly (100) through an open end of a battery housing (200), a second step of covering an open end of the battery housing (200) with a cap (300), a third step of inserting a liquid injection plug preform (40) into a liquid injection port (H1) formed in the cap (300), a fourth step of inserting a gasket (500) between the liquid injection plug preform (40) and the cap (300), and a fifth step of connecting a riveting gun (G) to a mandrel (60) inserted into the liquid injection plug preform (40) and pulling the riveting gun (G) upward to seal the liquid injection port (H1).

[0178] First, a battery housing (200) having an open end is prepared, and an electrode assembly (100) can be assembled into the battery housing (200) through the open end (first step).

[0179] Subsequently, the open end of the battery housing (200) can be covered with a cap (300) (Step 2). At this time, the contact point between the open end of the battery housing (200) and the cap (300) can be joined. For example, the joining point between the open end of the battery housing (200) and the cap (300) can be joined by welding. For example, the cap (300) can be joined to the battery housing (200) using butt welding. Thus, the battery cell (10) can have a larger internal capacity at the same external shape than a battery cell using beading and crimping methods. Thus, the energy density of the battery cell (10) can be increased. However, the battery housing (200) and the cap (300) can be joined by other joining methods other than welding, and the joining method is not limited to this.

[0180] Afterward, a liquid injection plug preform (40) can be inserted into the liquid injection port (H1) formed in the cap (300) as shown in FIG. 12 (Step 3). The liquid injection plug preform (40) may represent the state before the liquid injection plug (400) is riveted. The liquid injection plug preform (40) may be extended axially to penetrate the liquid injection port (H1). An axially extended mandrel hole (H2') may be formed in the liquid injection plug preform (40).

[0181] Additionally, a step of inserting a gasket (500) between the injection stopper preform (40) and the cap (300) can be performed (step 4).

[0182] Steps 3 and 4 can be performed by first performing the step of inserting the gasket (500) and then performing the step of inserting the injection plug preform (40), or by fitting the injection plug preform (40) into the gasket (500) and then inserting it.

[0183] The liquid injection plug preform (40) may include a main body preform (41) and a flange preform (42). The main body preform (41) has substantially the same configuration as the main body portion (410) of the liquid injection plug (400) and may be the form of the liquid injection plug (400) before it is riveted. Specifically, the main body preform (41) may be a portion that extends axially to penetrate the liquid injection port (H1). The flange preform (42) may have substantially the same configuration and form as the flange portion (420) of the liquid injection plug (400).

[0184] The mandrel hole (H2') may extend from the upper surface of the liquid stopper preform (40) in the direction of the winding axis. The mandrel hole (H2') of the liquid stopper preform (40) has substantially the same configuration as the mandrel hole (H2) of the liquid stopper (400) and may be in the form prior to the liquid stopper (400) being riveted. The mandrel hole (H2') may be formed to penetrate the center of the liquid stopper preform (40). The mandrel hole (H2') may penetrate the center of at least a portion of the flange preform (42) and the main body preform (41) of the liquid stopper preform (40). The mandrel hole (H2') may be a hole into which the mandrel (60) is inserted or removed. The upper portion of the mandrel hole (H2') may be open, and the lower end of the mandrel hole (H2') may be sealed. The mandrel hole (H2') can be sealed by the main body preform (41).

[0185] Referring to FIG. 14, the mandrel hole (H2') can be divided into a first region (H2'-1) with an inner diameter of a first length (r2) and a second region (H2'-2) with an inner diameter of a second length (r3) that is longer than the first length. That is, the second region (H2'-2) is concentric with the first region (H2'-1) and may have an inner diameter greater than or equal to the inner diameter of the first region (H2'-1). The second region (H2'-2) may be located below the first region (H2'-1).

[0186] The mandrel (60) may be configured to be inserted into the mandrel hole (H2'). The mandrel (60) may include a mandrel pin portion (61), a mandrel head portion (62) located at the lower end of the mandrel pin portion (61), and a weak portion (63) located between the mandrel pin portion (61) and the mandrel head portion (62).

[0187] A portion of the mandrel pin (61) may protrude outward from the injection plug preform (40), and another portion may be located within the mandrel hole (H2') of the injection plug preform (40). A portion of the mandrel pin (61) may be located in the first region (H2'-1) within the mandrel hole (H2). The upper portion of the mandrel pin (61) may be connected to a riveting gun (G).

[0188] Referring to FIG. 14, the mandrel head portion (62) may be configured to extend radially outward from the mandrel pin portion (61). The mandrel head portion (62) may be located in a second region (H2'-2) within the mandrel hole (H2'). The diameter (d4) of the mandrel head portion (62) may be longer than the first length (r2) and shorter than the second length (r3). Thus, when the mandrel (60) is pulled upward, the mandrel head portion (62) may catch on the protruding surface (43) of the liquid plug preform (40) surrounding the first region (H2'-1). At this time, if the force (tension) pulling the mandrel (60) upward exceeds the yield point of the liquid plug preform (40) material, at least a portion of the liquid plug preform (40) may be plastically deformed.

[0189] The weak part (63) may be a part that is relatively weak compared to the mandrel pin part (61) and the mandrel head part (62) when a certain force is applied. For example, the weak part (63) may have a smaller diameter than the mandrel pin part (61). That is, the weak part (63) may be a recessed area that is recessed inwardly in the direction of the winding axis compared to the mandrel pin part (61).

[0190] When the mandrel (60) is pulled upward, the mandrel pin portion (61) and the mandrel head portion (62) can be separated from the weak portion (63) when a force greater than a certain amount is applied. After at least a portion of the injection plug preform (40) has been plastically deformed, the mandrel (60) can be segmented at the weak portion (63) when a force greater than a certain amount is applied to the mandrel (60). That is, the mandrel head portion (62) and the mandrel pin portion (61) can be separated. In this case, the mandrel head portion (62) is embedded within the injection plug preform (40), and the mandrel pin portion (61) can be removed to the outside of the mandrel hole (H2).

[0191] The mandrel (60) may include a rigid metal material. For example, the mandrel (60) may include aluminum (Al), iron (Fe), stainless steel (SUS), etc. For example, the mandrel (60) may include iron.

[0192] Afterwards, a riveting gun (G) can be connected to the mandrel (60) inserted into the injection plug preform (40), and the riveting gun (G) can be pulled upward to seal the injection port (H1) (step 5).

[0193] When the riveting gun (G) connected to the mandrel (60) is pulled upward, the liquid injection plug preform (40) can be plastically deformed by the tension. Specifically, the axial length (W') of the liquid injection plug preform (40) can be reduced (referring to FIG. 6 and FIG. 12, it can be reduced from W' to W). Additionally, the maximum diameter (d1) of the main body preform (41) of the liquid injection plug preform (40) can be extended longer than the inner diameter of the liquid injection port (H1) (referring to FIG. 6 and FIG. 12, it can be extended from d1 to d1').

[0194] The main body preform (41) of the liquid injection stopper preform (40) may correspond to the main body part (410) and the plastic deformation part (430) of the liquid injection stopper (400). In other words, the part of the main body preform (41) of the liquid injection stopper preform (40) that is plastically deformed by riveting can be defined as the plastic deformation part (430).

[0195] When the riveting gun (G) connected to the mandrel (60) is pulled upward, the shape of the gasket (500) may be deformed by the tension. The gasket (500) may be deformed in response to the plastic deformation of the injection plug preform (40). That is, the gasket (500) may also be deformed by the force of the plastic deformation of the injection plug preform (40).

[0196] Specifically, when the riveting gun (G) connected to the mandrel (60) is pulled upward, the gasket (500) can be compressed in the direction of the winding axis. The length of the gasket (500) in the direction of the winding axis can be reduced. At the same time, the length of the gasket (500) in the radial direction can be expanded. According to the above embodiment of the present invention, the gasket (500) is compressed by riveting pressure (e.g., tension) to prevent leakage of internal gas or electrolyte of the battery housing (200).

[0197] Referring to FIG. 12, the cross-section cut along the winding axis of the gasket (500) before compression may be circular. For example, the diameter in the winding axis direction of the cross-section cut along the winding axis of the gasket (500) may be reduced (referring to FIG. 12 and FIG. 6, it may be reduced from o' to o1). For example, the diameter in the radial direction of the cross-section cut along the winding axis of the gasket (500) may be expanded (referring to FIG. 12 and FIG. 6, it may be expanded from o' to o2).

[0198] Referring to FIG. 13, the cross-section cut along the winding axis of the gasket (500) before compression may be in the shape of a rectangle or a bar extending along the winding axis. For example, the maximum radial diameter of the cross-section cut along the winding axis of the gasket (500) may be expanded (corresponding to the maximum diameter of the injection stopper (400) being expanded from d1 to d1' when referring to FIG. 6 and FIG. 12). For example, the length along the winding axis of the cross-section cut along the winding axis of the gasket (500) may be reduced (corresponding to the length along the winding axis of the injection stopper (400) being reduced from W' to W when referring to FIG. 6 and FIG. 12).

[0199] According to one embodiment, in the process of riveting the injection plug preform (40) to the battery housing (200), the injection plug (400) can be fixed on the outside of the battery housing (200). According to one embodiment of the present invention, riveting can be performed on the outside of the battery housing (200). Accordingly, the occurrence of foreign matter inside the battery housing (200) can be suppressed during the manufacture of the battery cell (10).

[0200] According to one embodiment, between the second and third steps, the method may further include an electrolyte injection step, a pre-charge step for partially charging the battery cell (10) to activate the battery cell (10), an activation step for charging the battery cell (10) to a higher voltage, and a degassing step for removing gas generated inside the battery cell (10).

[0201] The electrolyte injection step may be a step of injecting the electrolyte into the injection port (H1). By injecting the electrolyte into the battery housing (200), ions constituting the electrolyte (e.g., lithium ions) can move smoothly between the first electrode and the second electrode. However, after the electrolyte injection step, the electrolyte may remain in the vicinity of the injection port (H1) (periphery of the injection port (310)). Therefore, the remaining electrolyte can be removed by a laser cleaning process or the like.

[0202] The pre-charge stage is an initial charging process that can generally proceed slowly with a low current, which increases the stability of the battery cell (10) and reduces the risk of thermal runaway that may occur during future charging and discharging processes.

[0203] The activation step (formation) is a process of applying repeated charging and discharging to the battery cell (10), and by precisely controlling the charging rate and discharging rate, it is possible to check whether the battery cell (10) is operating normally.

[0204] The degassing step may be a step for removing gas remaining inside the battery cell (10). If gas generated during the activation step, which involves repeated charging and discharging, remains inside the battery cell (10), it may cause problems such as expansion of the battery cell (10) or an increase in internal pressure. In particular, a degassing step may be necessary for materials that generate a large amount of gas, such as nickel-cobalt-manganese (NCM) batteries and manganese-rich (Mn-rich) batteries. Therefore, the gas can be discharged by creating a vacuum in the battery cell (10) or using special equipment. When the gas inside the battery cell (10) is removed, the risk of volume expansion of the battery cell (10), damage to the battery cell (10), or ignition is reduced, and the battery cell (10) can maintain a stable lifespan and performance.

[0205] FIG. 15 is a drawing for explaining a battery pack according to an embodiment of the present invention. FIG. 16 is a drawing for explaining a vehicle including the battery pack of FIG. 15.

[0206] Referring to FIG. 15, the battery pack (1) according to the present invention may include at least one battery cell (10) according to the present invention as described above. Additionally, the battery pack (1) according to the present invention may include a pack housing (2) capable of accommodating the at least one battery cell (10). The battery pack (1) may be constructed using a battery module, which is an intermediate form of assembly, or the battery pack (1) may be constructed directly without a battery module as illustrated. Since the battery cell (10) itself has a large volume, there may be no particular difficulty in implementing the battery pack (1) even without using an intermediate structure called a battery module.

[0207] In addition, the battery pack (1) may further include various other components in addition to the battery cell (10), such as a BMS, a pack case, a relay, a current sensor, etc., components of the battery pack (1) known at the time of filing the present invention.

[0208] A battery pack (1) may include a plurality of battery cells (10). The battery cells (10) may be arranged in a predetermined number of rows, and each battery cell (10) may be arranged such that an electrode terminal (220) having a first polarity and an electrode terminal (210) having a second polarity are both positioned on the upper side. Therefore, when electrically connecting a plurality of battery cells (10), both positive and negative electrodes can be connected in one direction, thereby simplifying the electrical connection structure. Through this, the number of battery cells (10) that can be mounted in the same space can be increased to improve energy density, and electrical wiring work can be performed easily. Therefore, space efficiency is good and electrical wiring efficiency is high, resulting in significant work improvement effects during the assembly process of an electric vehicle and during the assembly and maintenance of the battery pack (1). Additionally, as previously explained, each battery cell (10) may have a higher energy density than conventional ones. A battery pack (1) with such increased energy density can store the same amount of energy while reducing its volume and load.

[0209] Therefore, if a battery pack (1) with such battery cells (10) is installed in a vehicle such as a car (M) that uses electricity as an energy source as shown in FIG. 16, the vehicle's mileage relative to energy can be further increased.

[0210] In addition, since electrical wiring is performed on the bottom of the battery housing (200) and on the side where the electrode terminal (210) is located, and electrical wiring may not be placed on the cap (300) located on the opposite side, the effect of the vent can be maximized if a vent portion (V) is configured in the cap (300) so that it can be vented toward the cap (300). Also, if a heat sink, cooling plate, or tray is placed on the side of the cap (300), purposes such as assembly and cooling can be effectively achieved regardless of the electrical wiring connection point. Furthermore, by assembling the vent portion (V) so that it is positioned downward, the gas discharged from inside the secondary battery is discharged downward. Since secondary batteries are usually mounted at a position lower than the occupants of a vehicle such as an EV, if gas is discharged upward from the secondary battery, it can cause harm to the occupants. The battery cell (10) of the present invention is not only capable of effectively discharging high-pressure gas inside the secondary battery, but is also safe as it is independent of the upper electrical wiring connection part, and furthermore, since the gas is discharged downward when the vent part (V) breaks and does not cause harm to the occupant, the safety is greatly improved.

[0211] Referring to FIG. 16, the automobile (M) according to the present invention may include at least one battery pack (1) according to the present invention.

[0212] The battery cell (10) according to the present invention can be applied to a vehicle such as an electric vehicle or a hybrid vehicle. That is, the vehicle (M) according to the present invention may include the battery cell (10) according to the present invention or the battery pack (1) according to the present invention. In addition, the vehicle (M) according to the present invention may further include various other components included in the vehicle in addition to the battery cell (10) or the battery pack (1). For example, the vehicle (M) according to the present invention may further include a vehicle body, a motor, a control device such as an ECU (electronic control unit), in addition to the battery cell (10) according to the present invention. The vehicle (M) includes four-wheeled vehicles and two-wheeled vehicles. The vehicle (M) may operate by receiving power from the battery pack (1) according to one embodiment of the present invention.

[0213] Although the present invention has been described above by 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 spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. An electrode assembly comprising a first electrode and a second electrode and a separator interposed between them, wound along a winding axis; A battery housing configured to accommodate the electrode assembly through an open end formed on one side; A cap covering the above-mentioned open end and having an injection port formed in the center; A liquid injection stopper configured to be inserted into the liquid injection port and configured to seal the liquid injection port; and A gasket interposed between the above injection stopper and the above cap, having chemical resistance to the electrolyte; A battery cell containing 2. In Paragraph 1, A battery cell characterized by the above gasket having a heat deformation temperature of 130 degrees or more and 170 degrees or less at a load of 66 psi.

3. In Paragraph 1, A battery cell characterized by the above gasket having a moisture absorption rate of 0.05% or more and 0.15% or less.

4. In Paragraph 1, A battery cell characterized by the above gasket having a tensile strength of 50 MPa or more and 70 MPa or less.

5. In Paragraph 1, A battery cell characterized in that the above gasket comprises polybutylene terephthalate (PBT).

6. In Paragraph 1, A battery cell characterized in that the above-mentioned injection cap is composed of a blind rivet.

7. In Paragraph 1, The above injection stopper is A main body inserted into the above injection port; A flange portion covering the injection port on the upper side of the cap and extending outward in a radial direction perpendicular to the winding axis direction from the upper end of the main body portion; and A battery cell characterized by including at least a portion of a plastically deformed portion extending outward in the radial direction from the lower portion of the main body.

8. In Paragraph 7, A battery cell characterized in that the diameter of the flange portion is larger than the inner diameter of the injection port.

9. In Paragraph 7, A battery cell characterized in that the maximum diameter of the plastic deformation portion is larger than the inner diameter of the injection port.

10. In Paragraph 7, A battery cell characterized in that at least a portion of the plastically deformed portion comprises a horizontal plane substantially parallel to the lower surface of the cap.

11. In Paragraph 1, A battery cell characterized by having a mandrel hole formed in the above-described injection plug, extending in the direction of the winding axis from the upper surface of the above-described injection plug.

12. In Paragraph 1, A battery cell characterized by further including a mandrel piece disposed inside the above-mentioned injection plug.

13. In Paragraph 1, A battery cell characterized in that the above-mentioned injection plug comprises a material having elongation.

14. In Paragraph 1, A battery cell characterized in that the above gasket is in the shape of a ring surrounding the periphery of the injection port.

15. In Paragraph 7, A battery cell characterized in that the above gasket is disposed between the upper surface of the cap and the lower surface of the flange portion of the liquid injection plug.

16. In Paragraph 1, A battery cell characterized in that the above gasket has a circular cross-section cut along the direction of the winding axis centered on the winding axis.

17. In Paragraph 1, A battery cell characterized in that the gasket has a rectangular cross-section cut along the direction of the winding axis centered on the winding axis.

18. In Paragraph 7, A battery cell characterized in that the above gasket surrounds the sides of the main body and the plastically deformed part, and has a cylindrical structure with both sides open toward the winding axis.

19. In Paragraph 18, A battery cell characterized in that the above gasket includes a curved surface and at least a portion protrudes radially.

20. In Paragraph 1, A battery cell characterized by the above gasket having an elongation rate of 40% or more and 150% or less.

21. In Paragraph 1, A battery cell characterized by the above gasket having a flexural modulus of 300 MPa or more and 2500 MPa or less.

22. A first step of inserting an electrode assembly, in which the first electrode and the second electrode and a separator interposed between them are wound along a winding axis, through an open end of a battery housing; A second step of covering the open end of the battery housing with a cap; A third step of inserting an injection stopper preform into the injection port formed in the cap: A fourth step of inserting a gasket between the above injection stopper preform and the above cap; and A method for manufacturing a battery cell comprising: a fifth step of connecting a riveting gun to a mandrel inserted into the injection plug preform, and pulling the riveting gun upward to seal the injection port.

23. In Paragraph 22, A method for manufacturing a battery cell characterized by plastic deformation of the injection plug preform when the above riveting gun is pulled upward.

24. In Paragraph 22, A mandrel hole extending in the direction of the winding axis is formed in the above injection stopper preform, and A battery cell manufacturing method characterized by being configured such that the mandrel is inserted into the mandrel hole.

25. In Paragraph 24, A method for manufacturing a battery cell, characterized in that the above mandrel comprises: a mandrel pin portion in which at least a portion protrudes outwardly from the injection plug preform; a mandrel head portion extending radially outwardly from the lower end of the mandrel pin portion than the mandrel pin portion; and a weak portion located between the mandrel pin portion and the mandrel head portion.

26. In Paragraph 25, A method for manufacturing a battery cell, characterized in that the above mandrel hole comprises: a first region having an inner diameter of a first length; and a second region located below the first region and having an inner diameter of a second length longer than the first length.

27. In Paragraph 26, A method for manufacturing a battery cell characterized in that the diameter of the above mandrel head portion is longer than the above first length.

28. In Paragraph 22, A battery cell manufacturing method characterized by the fact that when the above mandrel is pulled upward, the length in the winding axis direction of the above injection plug preform is reduced, and the maximum diameter of the above injection plug preform is extended longer than the inner diameter of the above injection port.

29. In Paragraph 22, A battery cell manufacturing method characterized by the fact that when the above mandrel is pulled upward, the gasket is compressed in the direction of the winding axis, and the length of the gasket in the direction of the winding axis is reduced.

30. In Paragraph 25, A battery cell manufacturing method characterized by the fact that when the above mandrel is pulled upward, the mandrel pin portion and the mandrel head portion are separated from the above vulnerable portion when a force greater than a certain amount is applied.

31. In Paragraph 22, A step of injecting an electrolyte into the injection port between the second step and the third step; A pre-charge step for partially charging the battery cell to activate the battery cell; An activation step for charging the above battery cell to a higher voltage; and A method for manufacturing a battery cell, further comprising a degassing step for removing gas generated inside the battery cell.

32. A battery pack characterized by comprising at least one battery cell described in any one of claims 1 to 21.

33. An automobile characterized by comprising at least one battery cell described in any one of claims 1 to 21.

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