Battery cell, and battery pack and vehicle comprising same

Abstract

The present invention may provide a battery cell comprising: a battery can; an electrode assembly accommodated through an opening of the battery can and having a first electrode, a second electrode, and a separator interposed therebetween, which are wound around a winding axis; and a venting part having a shape recessed to a predetermined depth so as to be ruptured by a predetermined pressure, wherein a filling member is disposed along the recessed shape of the venting part and is at least partially filled within the range of a recessed depth.

Description

Battery cells, battery packs including the same, and automobiles

[0001] The present invention relates to a battery cell, a battery pack including the same, and an automobile, and more specifically, to a battery cell capable of improving corrosion resistance, a battery pack including the same, and an automobile.

[0002] This application is a priority application for Korean Patent Application No. 10-2025-0049508 filed on April 16, 2025, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference.

[0003] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product groups, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric sources. These secondary batteries are attracting attention as a new energy source for enhancing eco-friendliness and energy efficiency, as they possess not only the primary advantage of drastically reducing the use of fossil fuels but also the advantage of generating no by-products from energy use.

[0004] Rechargeable batteries are utilized as battery modules or battery packs, which are assembled into a dense structure by overlapping or stacking multiple battery cells to provide high voltage and high current, and then electrically connected. In this process, it is common practice to first construct a battery module containing at least one battery cell, and then use this module to construct a battery pack by adding other components. Alternatively, recently, battery packs in the form of "Cell-to-Pack," in which multiple battery cells are directly housed within a pack housing without modularization, are also being manufactured. There is an increasing demand for the use of metal can-type battery cells for automotive battery packs. The shape of the metal can can be prismatic or cylindrical; cylindrical battery cells feature a structure that accommodates a jelly-roll type electrode assembly inside the cylindrical can, offering the advantage of being more robust against shock and temperature than pouch-type battery cells.

[0005] Meanwhile, battery cells may be exposed to various environments depending on their usage conditions, and it is particularly necessary to prevent the risk of explosion for the safety of users. Generally, high temperatures and high pressures inside a battery cell, which can be caused by abnormal operating conditions such as internal short circuits, charging states exceeding permitted current or voltage, exposure to high temperatures, or impacts from drops, can lead to the explosion of the battery cell.

[0006] In particular, the can lid, a fundamental component of the battery cell, functions as a current path responsible for electrical connection with the external circuit; therefore, its material and structure can directly affect the battery cell's internal resistance and performance. Accordingly, nickel-plated steel (NPS) may be more advantageous than stainless steel (SUS) for the can lid. However, if a notch is formed on the can lid to relieve high pressure, the nickel plating may peel off from the sidewalls. Such plating peeling can cause surface damage during transport or lead to localized corrosion due to contact with the electrolyte during battery cell assembly and use, thereby posing a risk of battery cell performance degradation.

[0007] Therefore, a new design structure for battery cells is required that can relieve high pressure, which is the direct cause of battery cell explosions, and prevents plating damage or corrosion.

[0008] The present invention was devised in consideration of the aforementioned problems and has one objective of providing a battery cell equipped with a high-pressure relief means.

[0009] Alternatively, in one aspect, one objective is to provide a battery cell with improved corrosion resistance.

[0010] Another objective of the present invention is to provide a battery pack comprising such battery cells and a vehicle comprising the same.

[0011] However, the technical 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.

[0012] To solve the above objective, the present invention comprises: a battery can having a side wall member, a bottom member connected to one axial end of the side wall member, and an opening provided at the other axial end of the side wall member as a battery cell; an electrode assembly received through the opening of the battery can, wherein a first electrode and a second electrode and a separator interposed between them are wound around a winding axis; and a venting portion having a shape recessed to a predetermined depth such that it breaks under a predetermined pressure, wherein a filling member is arranged along the recessed shape of the venting portion, and the filling member may be filled at least partially within the recessed depth range.

[0013] For example, the filling material may be applied in a liquid state to at least a portion of the outer surface of the venting portion and then cured.

[0014] For example, the filling material may be selectively applied locally along the indented shape of the venting portion.

[0015] For example, the above-mentioned filling material may include a silicone-based, urethane-based, or epoxy-based polymer.

[0016] For example, the filling member may be formed so as not to exceed the indentation depth of the venting portion.

[0017] For example, the device further includes a can lid covering an opening of the battery can, and the venting portion may include a vent portion having a closed-loop shape along the circumferential direction on the can lid.

[0018] For example, the can lid comprises a first metal layer and a second metal layer formed on the first metal layer, and the vent portion is formed as an area where the second metal layer is removed and the first metal layer is exposed, and the filling member may be applied on at least one surface of the exposed first metal layer.

[0019] For example, the filling member may be formed to cover the area where the first metal layer is exposed to inhibit corrosion.

[0020] For example, the above-mentioned filling member may not be disposed on the second metal layer.

[0021] For example, the first metal layer comprises nickel, the second metal layer comprises iron, and the filling member may be formed of a polymer.

[0022] For example, the above-mentioned filling material can be applied and cured in a closed-loop shape along the circumferential direction.

[0023] For example, the venting portion may include a vent notch portion having a closed-loop shape along the circumferential direction on the bottom member of the battery can.

[0024] For example, the above-mentioned vent notch portion may have the filling material locally and selectively applied on at least one surface.

[0025] In addition, the present invention may provide a battery pack comprising a battery cell according to the present invention as a battery pack.

[0026] In addition, the present invention can provide a vehicle comprising a battery pack according to the present invention as a vehicle.

[0027] According to the present invention, a battery cell comprising a vent notch portion that serves as a means for relieving high pressure in a battery cell using butt welding may be provided.

[0028] Alternatively, in one aspect, when the gas inside the battery cell of the present invention fills up to a pressure above a certain level, the vent notch ruptures, thereby relieving the high pressure that is the direct cause of the battery cell explosion.

[0029] Alternatively, in one aspect, the battery cell of the present invention can prevent corrosion of the vent notch portion during transport or use.

[0030] Alternatively, in one aspect, the battery cell of the present invention can further increase energy density by simplifying the joint between the can lid and the battery can and securing more internal volume.

[0031] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0032] FIG. 1 is a schematic diagram showing a battery cell according to one embodiment of the present invention.

[0033] FIGS. 2 and FIGS. 3 are schematic diagrams showing the state before and after lamination of the first electrode, the second electrode, and the separator for fabricating the electrode assembly of the battery cell of FIG. 1.

[0034] Figure 4 is a schematic diagram showing an electrode assembly fabricated by winding the laminate of Figure 3 into a jelly-roll shape.

[0035] Figure 5 is a side cross-sectional view of the battery cell of Figure 1.

[0036] Figure 6 is a partial enlarged view of area A of Figure 5.

[0037] Figure 7 is a drawing for explaining how a filling material is applied to the vent portion of the battery cell of Figure 1.

[0038] FIG. 8 is a schematic diagram showing a battery cell according to another embodiment of the present invention.

[0039] FIG. 9 is a schematic diagram showing a battery pack including a battery cell of the present invention.

[0040] FIG. 10 is a schematic diagram showing a vehicle including a battery pack of the present invention.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0046] 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.

[0047] 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.

[0048] Throughout the specification, when "A and / or B" is used, it may mean A, B, or A and B unless specifically stated otherwise.

[0049] 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 it is obvious to those skilled in the art to which this invention pertains that they may vary depending on the position or arrangement, rotation, or position of the observer of the object in question.

[0050] The present invention may be implemented in the following embodiments, each independently. Furthermore, the present invention may be implemented in combination of two or more of the following embodiments. Each of the following embodiments may not only be implemented independently but may also be freely combined with one another.

[0051] For convenience of explanation, the longitudinal direction of the winding axis of an electrode assembly wound in a jelly roll shape is referred to as the winding axis direction in this specification. The direction surrounding the winding axis of the electrode assembly is referred to as the circumferential direction, and the direction in which the electrode assembly proceeds as it is wound along the winding axis is referred to as the winding direction. Furthermore, the direction moving away from or closer to the winding axis of the electrode assembly is referred to as the radial direction.

[0052]

[0053] First, the components of the battery cell (1) of the present invention are described in detail.

[0054] FIG. 1 is a schematic diagram showing a battery cell (1) according to one embodiment of the present invention, FIG. 2 and FIG. 3 are schematic diagrams showing the state before and after lamination of the first electrode (21), the second electrode (22), and the separator (28) for manufacturing the electrode assembly (20) of the battery cell (1) of FIG. 1, FIG. 4 is a schematic diagram showing an electrode assembly (20) manufactured by winding the laminate of FIG. 3 into a jelly-roll shape.

[0055] First, referring to FIGS. 1 to 4, the battery cell (1) of the present invention may be a cylindrical battery cell. For example, the battery cell (1) may be a cylindrical battery cell in which the ratio of the form factor (defined as the ratio of the diameter of the cylindrical battery cell to the height, i.e., the ratio of the diameter to the height) is approximately greater than 0.4. Of course, the battery cell (1) may be a cylindrical battery cell in which the ratio of the form factor is approximately equal to or less than 0.4. As an example, the diameter of the battery cell (1) may be 40 mm to 50 mm, and the height may be 60 mm to 130 mm.

[0056] Here, the form factor may refer to a value representing the diameter and height of a cylindrical battery cell. The cylindrical battery cell may be a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell by applying a numerical value representing the form factor. Here, the first two digits represent the diameter of the cell, the next two digits represent the height of the cell, and the last digit 0 indicates that the cross-section of the cell is circular. However, the shape of the battery cell (1) according to the present invention is not limited by the above and can be applied to batteries of other shapes. For example, it may be applied to prismatic batteries.

[0057] The battery cell (1) according to the present embodiment may largely include a battery can (10), an electrode assembly (20), and a can lid (40).

[0058] The battery can (10) may be a cylindrical structure for a cylindrical battery cell. In this case, a side wall member (11) forms the side of the cylinder of the battery can (10), and one axial end of the side wall member (11) becomes a closed part of the battery can (10), and the other end of the battery can (10) opposite the closed part is open and may become an opening. However, the battery can (10) is not limited to the shape shown in FIG. 1 and may be formed in various shapes. As an example, the battery can (10) may be designed to have openings at both axial ends of the side wall member (11).

[0059] The closed portion may be in the shape of a disc with a through hole formed in the center, and the side wall member (11) may be in the shape of a cylinder having a constant radius along the circumferential direction surrounding the closed portion. The battery can (10) may be a member formed by a deep drawing process of a metal sheet having nickel plated on the surface of steel.

[0060] The electrode assembly (20) can be accommodated inside the battery can (10) through the opening of the battery can (10).

[0061] As an example, the electrode assembly (20) may be configured such that the first electrode (21) and the second electrode (22) and the separator (28) interposed between them are wound around a winding axis. After the winding is completed, the electrode assembly (20) may be in the form of a jelly-roll.

[0062] The outer shape of the electrode assembly (20) along the circumferential direction of the electrode assembly (20) may be circular. However, the structure of the electrode assembly (20) is not limited by the embodiment and may have a wound structure well known in the art.

[0063] The first electrode (21), the second electrode (22), and the separator (28) may each have a predetermined width along the winding axis direction and be formed to extend a predetermined length along the winding direction. The first electrode (21) may be an anode plate, and the second electrode (22) may be a cathode plate. Of course, the opposite may also be true.

[0064] The first electrode (21) and the second electrode (22) may be manufactured in the form of a sheet. The first electrode (21) and the second electrode (22) may be configured such that an active material layer is applied to at least a portion of the surface of the metal foil (23). The first electrode (21) and the second electrode (22) may have a retaining portion (24) where the active material layer is applied and a non-retaining portion (26) where the active material layer is not applied.

[0065] The uncoated portion (26) can be exposed to the outside of the separator (28) while forming a plurality of winding turns based on the winding axis of the electrode assembly (20), and can be used as an electrode tab itself. That is, the positive plate and the negative plate may each include an uncoated portion (26) in which no active material is coated at the long side end in the direction of the winding axis. In addition, the uncoated portions (26) of the first electrode (21) and the second electrode (22) may be configured to face opposite directions in the direction of the winding axis. The uncoated portion (26) of the first electrode (21) may be housed inside the battery can (10) so that it is located at one end in the direction of the winding axis, and the uncoated portion (26) of the second electrode (22) 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.

[0066] Also, the separator (28) may be a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., used alone or in a laminated form. As another example, the separator may be a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0067] At least one surface of the separator (28) may include a coating layer of inorganic particles. Additionally, it is possible for the separator (28) itself to be composed of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure combined with a binder such that interstitial volume exists between adjacent particles.

[0068] This non-removable part (26) can itself function as an electrode tab.

[0069] The unwound portion (26) can form multiple flag-shaped notching tabs (27) by forming notches at predetermined intervals along the winding direction. The multiple notching tabs (27) may be in the shape of an isosceles trapezoid arranged along the winding direction. However, they are not limited thereto and may be in various shapes such as a semicircle, semi-ellipse, triangle, rectangle, parallelogram, etc.

[0070] Additionally, a plurality of notching tabs (27) can be flattened by bending them radially in the electrode assembly (20). Additionally, the notching tabs (27) can be bent radially inward or outward in the electrode assembly (20).

[0071] Additionally, multiple notching tabs (27) may be folded one by one during the process of forming a jelly-roll type electrode assembly (20). Alternatively, the notching tabs (27) may be folded all at once after forming the jelly-roll type electrode assembly (20).

[0072] In this way, the notching tabs (27) of the first electrode (21) and the notching tabs (27) of the second electrode (22), which are folded and stacked in the radial direction, can each provide a plane that is substantially perpendicular to the winding axis direction at both ends of the winding axis direction of the electrode assembly (20).

[0073] The can lid (40) can be configured to cover the opening of the battery can (10) with respect to the central axis. This ensures that the battery cell (1) is airtight and can be combined with a plug (50) for sealing after the electrolyte is injected. This protects the internal electrolyte (electrolyte) and the electrode assembly (20) from the external environment and maintains the long-term performance of the battery cell (1).

[0074] The can lid (40) is provided with a conductive material, and the thickness of the can lid (40) can be designed to provide sufficient strength to prevent deformation in a high temperature or high pressure environment and to ensure durability to prevent leakage of the internal electrolyte.

[0075] The can lid (40) can be attached to the battery can (10) using butt welding. Thus, the battery cell (1) can have a larger internal capacity in the same shape than a battery cell (1) using beading and crimping methods. Thus, the energy density can be increased.

[0076] The battery cell (1) according to the present embodiment may include a venting portion. In this specification, the venting portion is a vulnerable area formed to rupture when the pressure inside the battery cell (1) increases above a predetermined level, and can perform a safety function of preventing damage or explosion of the battery cell (1) by releasing the internal pressure to the outside.

[0077] These venting portions can be formed at various locations. For example, as shown in FIG. 1, the venting portion may be provided as a vent portion (43) formed on a can lid (40). In this case, the vent portion (43) may be implemented as a structure having a shape that is recessed to a predetermined depth.

[0078] Meanwhile, the venting section is typically formed through notching, a process in which a metal layer, such as a nickel (Ni) plating layer, is partially peeled off or removed, potentially exposing the underlying iron (Fe)-based metal. This exposed metal comes into direct contact with the electrolyte or the external environment, posing a risk of corrosion during component transfer or prolonged use. In particular, since the venting section is a structurally vulnerable area, such corrosion can lead to instability in venting characteristics or a decrease in mechanical reliability.

[0079] Accordingly, in this embodiment, a filling material (100) can be applied to at least a portion of the venting part to improve the corrosion resistance of the venting part and to suppress corrosion and deterioration phenomena that may be caused by the external environment.

[0080] The filling member (100) can function as a protective layer to prevent local corrosion that may occur on the surface of the venting section due to external factors such as moisture, electrolyte vapor, and salt, and can provide effective protective performance by selectively applying it to structurally vulnerable areas, such as the venting section.

[0081] Specifically, the filling member (100) may be arranged along the recessed shape formed in the venting portion. At this time, the filling member (100) may be formed to substantially follow the curvature and profile of the recessed shape, and accordingly, may exist in a state of close contact with the surface of the venting portion while performing the role of blocking direct contact with the external environment.

[0082] The filling member (100) can be formed to be filled at least partially within the recessed depth range of the venting part, and preferably formed so as not to exceed the recessed depth, thereby not causing a change in the external shape or an increase in height of the battery can (10), or minimizing the effect thereof.

[0083] The filling member (100) is not formed over the entire venting section, but can be applied locally to a limited vulnerable area as needed. For example, it can be selectively formed in an area within the venting section where stress concentration is likely to occur, or in an area where the metal layer is exposed and susceptible to corrosion, thereby ensuring maximum protection with minimal material usage. Such a localized coating structure improves efficiency in terms of the manufacturing process and can also contribute to reducing process time and costs by excluding coating on unnecessary areas.

[0084]

[0085] Hereinafter, the structure of the battery cell (1) of the present invention will be specifically described based on FIGS. 1 to 5.

[0086] FIG. 5 is a side cross-sectional view of the battery cell (1) of FIG. 1, and FIG. 6 is a partial enlarged view of area A of FIG. 5.

[0087] Referring to FIGS. 5 and 6, as an example, the can lid (40) of the battery cell (1) can be coupled to the opening of the battery can (10) in a press-fit manner, thereby ensuring airtightness and being stably fixed without a separate welding process. Additionally, the can lid (40) can be directly electrically connected to the electrode assembly (20), thereby forming a current path to transmit the current of the electrode assembly (20) to the outside.

[0088] Meanwhile, the battery cell (1) may further include a current collector (15) and an insulator (16).

[0089] The current collector plate (15) is a conductive member that is coupled to one end of the winding axis direction of the electrode assembly (20) and electrically connected to the metal foil (23) of the first electrode (21) of the electrode assembly (20), and can be configured to efficiently transmit the current inside the electrode assembly (20) to an external terminal, i.e., an electrode terminal (13).

[0090] The insulator (16) may be interposed between a collector plate (15) electrically connected to the first electrode (21) and a bottom member (12) at one end of the electrode assembly (20) in the direction of the winding axis, which is electrically connected to the electrode terminal (13). The insulator (16) may function as an insulating member that prevents internal short circuits by preventing electrical contact between, for example, a collector plate (15) and a bottom member (12) having opposite polarity at one end of the electrode assembly (20) in the direction of the winding axis.

[0091] According to the present embodiment, the venting portion may be provided as a vent portion (43) formed on the can lid (40).

[0092] The vent section (43) can be broken by the internal pressure of the high-temperature venting gas when a thermal event occurs in the battery cell (1), and accordingly, the venting gas can be discharged from the battery cell (1) to the outside. The vent section (43) can be broken when the pressure inside the battery cell (1) exceeds a critical value, and the pressure inside the battery cell (1) corresponding to the critical value can be defined as the vent pressure. The vent pressure in the battery cell (1) can be controlled by adjusting the thickness of the vent section (43) or by heat treatment.

[0093] The vent portion (43) can be formed by being recessed in the thickness direction, for example, in the winding axis direction. That is, the vent portion (43) can be designed so that when the internal pressure of the battery cell (1) rises, stress is concentrated in that area and selectively fractures by forming a weak portion with a thickness thinner than the surrounding thickness (d1), in a recessed area that is recessed to a predetermined depth (d2) in the thickness direction of the can lid (40) in which the vent portion (43) is provided.

[0094] A filling member (100) can be applied along the combined shape of the vent portion (43).

[0095] Meanwhile, the can lid (40) may be composed of a multilayer metal structure including a first metal layer and a second metal layer formed on the first metal layer, and the second metal layer may be formed through a plating process. For example, the first metal layer may include nickel (Ni), and the second metal layer may include iron (Fe). In such a structure, when the second metal layer is removed by notching, an area where the lower first metal layer is exposed to the outside may be formed. The filling member (100) may be selectively formed in at least a portion of the vent portion (43), that is, in the area where the first metal layer is exposed, thereby covering the exposed metal surface to block direct contact with the external environment or electrolyte. At this time, the filling member (100) may not be placed on the second metal layer. Accordingly, the filling member (100) can perform the role of suppressing corrosion that may occur in the vent portion (43) and improving the structural reliability of the vent portion (43).

[0096] Consequently, the battery cell (1) according to the present invention can effectively suppress corrosion and deterioration from the external environment by means of a filling member (100) disposed within the recessed shape, without impairing the structural function of the vent portion (43), namely, the stable fracture characteristics at a predetermined pressure. In particular, the locally applied filling member (100) selectively acts on vulnerable areas of the vent portion (43) to improve durability, while simultaneously maintaining the external shape and assembly of the battery can (10), thereby providing a highly advantageous technical effect for a secondary battery system requiring high reliability and high safety.

[0097]

[0098] FIG. 7 is a drawing for explaining how a filling material (100) is applied to the vent portion (43) of the battery cell (1) of FIG. 1.

[0099] Referring to FIG. 7 based on FIG. 5, the can lid (40) may include an electrode coupling portion (42). The electrode coupling portion (42) may be provided as at least one. The electrode coupling portion (42) may be provided as a plurality of parts.

[0100] The electrode coupling portion (42) can be coupled to one end of the winding shaft of the electrode assembly (20). The electrode coupling portion (42) can be welded to the electrode assembly (20). The bottom surface of the electrode coupling portion (42) (the surface facing the electrode assembly (20)) can be coupled to the electrode assembly (20) face-to-face. The bottom surface of the electrode coupling portion (42) can be coupled to the metal foil (23) of the second electrode (22) of the electrode assembly (20).

[0101] The electrode coupling portion (42) may be positioned relatively closer to the electrode assembly (20) than the surrounding portion. For example, in the can lid (40), the electrode coupling portion (42) may be formed by being recessed inward along the axial direction toward the electrode assembly (20). That is, the bottom surface of the electrode coupling portion (42) is formed protruding inward in the winding axis direction of the electrode assembly (20) compared to the rest of the bottom surface of the can lid (40), and may be provided closest to the electrode assembly (20). In this case, when the electrode coupling portion (42) is coupled to the electrode assembly (20), the remaining portion of the can lid (40), excluding the electrode coupling portion (42), may be spaced apart from the electrode assembly (20).

[0102] The can lid (40) may include an edge portion (41) formed in the edge area.

[0103] The edge portion (41) is configured to be coupled to the opening of the battery can (10), and, for example, can be provided in a roughly U shape so as to be press-fitted to the inner circumference of the side wall member (11) of the battery can (10).

[0104] The edge portion (41) may largely include a butt surface (411), a curved surface (412), and an inclined surface (413) extending from the radially outer side to the inner side. For example, the butt surface (411), the curved surface (412), and the inclined surface (413) of the edge portion (41) may form a roughly U shape.

[0105] The butt surface (411) is provided on the radial outer edge of the can lid (40) and can be extended in the direction of the central axis of the can lid (40) so that its outer surface contacts the inner surface of the side wall member (11). Thus, the butt surface (411) can be in close contact with the inner surface of the side wall member (11) over a predetermined length in the direction of the central axis.

[0106] The curved surface (412) may have a downwardly convex cross-sectional shape that is connected to the lower end of the butting surface (411), that is, the axial inner end of the butting surface (411), and extends radially inward as it moves inward in the direction of the center axis of the can lid (40). The slope of the curved surface (412) may gradually become gentler as it moves away from the butting surface (411). The slope of the tangent of the outer surface of the curved surface (412) may gradually decrease from 90 degrees as it moves away from the butting surface (411).

[0107] The inclined surface (413) may be connected at one radial end of the curved surface (412). That is, the inclined surface (413) may extend outward in the direction of the central axis of the can lid (40) as it moves inward in the radial direction.

[0108] The edge portion (41), which has an overall U shape as described above, provides a certain elastic force and may be suitable for being pressed into the opening of the battery can (10), that is, the inner circumference of the side wall member (11).

[0109] As a result, the battery cell (1) of the present embodiment can secure welding and assembly stability by increasing the contact area that comes into direct contact with the side wall member (11) by adjusting the shape or ratio of the edge portion (41) of the can lid (40).

[0110] As an example, the electrode coupling portion (42) may be provided in multiple numbers, and the multiple electrode coupling portions (42) may be spaced apart from each other. For example, the multiple electrode coupling portions (42) may be spaced apart from each other in the circumferential direction.

[0111] The can lid (40) can have a plurality of electrode coupling parts (42) spaced apart from each other and formed by indentation, so that the flatness with the electrode assembly (20) can be stably formed. The welding quality between the can lid (40) and the electrode assembly (20) according to one embodiment of the present invention can be improved.

[0112] A plurality of electrode coupling portions (42) can be formed and arranged symmetrically with respect to the center of the can lid (40). Each electrode coupling portion (42) can be formed with the same shape and arranged to be equal to each other with respect to the can lid (40). In this way, when a plurality of electrode coupling portions (42) are formed and arranged symmetrically, stable flatness between the can lid (40) and the electrode assembly (20) can be more easily secured, and the electrical stability of the battery cell (1) can also be improved.

[0113] The electrode coupling portion (42) may provide a bottom surface that extends flatly in the radial direction. The height of the bottom surface of the electrode coupling portion (42) may be lower than the height of the bottom portion of the curved surface (412). That is, the electrode coupling portion (42) may protrude further inward in the axial direction than the curved surface (412). Then, the bottom portion of the curved surface (412) may be spaced apart in the winding axis direction from the electrode assembly (20) housed inside the battery can (10), while the bottom surface of the electrode coupling portion (42) may be in close contact with the electrode assembly (20). Accordingly, the bonding process between the electrode coupling portion (42) and the electrode assembly (20) can be carried out smoothly.

[0114] The electrode coupling portion (42) may be provided on the inner side of the edge portion (41). Specifically, the electrode coupling portion (42) may be provided on the radially inner side of the edge portion (41).

[0115] The vent portion (43) may be extended in a direction perpendicular to the thickness direction. For example, the vent portion (43) may be extended along the circumferential direction in the can lid (40).

[0116] The cross-section of the vent portion (43) viewed from the direction in which the vent portion (43) extends (e.g., the circumferential direction) may be formed in a V-shape or a U-shape. If the cross-section of the vent portion (43) is formed in a V-shape, there may be an advantage that the fracture induction position can be precisely controlled, and if the cross-section of the vent portion (43) is formed in a U-shape, there may be an advantage that the venting gas discharge characteristics can be formed relatively smoothly. The cross-section of the vent portion (43) is not limited to a V-shape or a U-shape and may be configured in various other shapes.

[0117] The vent portion (43) may have a closed-loop shape. The vent portion (43) may be formed in a continuous pattern on the surface of the can lid (40). For example, the vent portion (43) may be formed using a curved pattern, a straight pattern, a circular pattern, a polygonal pattern, or various other shapes. Meanwhile, the vent portion (43) may also be formed in a discontinuous pattern on the surface of the can lid (40).

[0118] The can lid (40) of the present embodiment may further include an injection port (44) and a flat portion (45).

[0119] The injection port (44) can be configured so that electrolyte can be injected into the battery can (10) after the can lid (40) is attached to the battery can (10). This configuration is particularly useful when the battery can (10) and the can lid (40) are joined by welding. This is because if the injection is performed first and the welding is performed later, there is a risk of the weld quality deteriorating due to the vaporization of the electrolyte. The injection port (44) can be located in the center of the can lid (40). If the injection is performed before the can lid (40) is attached to the battery can (10), the can lid (40) may not be provided with an injection port (44).

[0120] The flat portion (45) may surround the injection port (44). The flat portion (45) may surround the injection port (44) approximately along the circumferential direction. The flat portion (45) may be provided with a shape in which at least a portion is flat. The flat portion (45) may serve to provide a contact surface with a can lid transport device, such as a can lid adsorption mechanism, on the upper surface of the can lid (40) while supplementing the rigidity of the area around the injection port (44).

[0121] The can lid (40) of the present embodiment may further include a picking portion (46).

[0122] The picking portion (46) may be positioned between two adjacent electrode coupling portions (42) and edge portions (41). The picking portion (46) may be referred to as a spacing portion. The picking portion (46) may be configured to partition two adjacent electrode coupling portions (42). A void space may be formed between the picking portion (46) and the electrode assembly (20). A predetermined picking area may be formed in the picking portion (46). The picking area may be grasped by a picking device. The diameter of the picking area may be formed to, for example, about 4 mm. However, this numerical range is merely an example and can be varied in many ways.

[0123] When the can lid (40) according to the present invention is equipped with a picking portion (46), a plurality of electrode coupling portions (42) can be more clearly partitioned, and a larger empty space can be formed between the can lid (40) and the electrode assembly (20). In addition, since the picking equipment may not come into contact with the electrode coupling portion (42), foreign substances such as foreign matter can be prevented from entering the electrode coupling portion (42) from the picking equipment, and the can lid (40) can be stably gripped and transported during the assembly process of the battery cell (1).

[0124] The can lid (40) of the present embodiment may further include at least one bridge (47).

[0125] The bridge (47) may be provided in multiple numbers, for example, in three numbers. The bridge (47) may extend radially from the flat portion (45). The bridge (47) may be formed to partition two adjacent electrode coupling portions (42). The bridge (47) may extend from the flat portion (45) toward the edge portion (41).

[0126] The bridge (47) may extend from the flat portion (45) toward the picking portion (46). The picking portion (46) may be provided between the bridge (47) and the edge portion (41). The upper surface of the picking portion (46) may be formed at a height higher than the upper surface of the bridge (47).

[0127] By means of the bridge (47), multiple electrode coupling parts (42) can be more clearly partitioned and separated. The bridge (47) can reinforce the rigidity of the can lid (40).

[0128] Meanwhile, the upper surface of the bridge (47) may be formed to be higher than the upper surface of the electrode coupling part (42) but lower than the upper surface of the flat part (45). When the bridge (47) is formed in this way, the rigidity of the can lid (40) can be reinforced more strongly. In addition, in this case, when plastic processing such as pressing to form the electrode coupling part (42), the bridge (47), which may have a width (e.g., circumferential width) that is relatively smaller than the electrode coupling part (42), can be efficiently processed without damage.

[0129] Additionally, the radial length between the edge portion (41) and the bridge (47) of the can lid (40) can be formed to be longer than the radial length between the edge portion (41) and the electrode coupling portion (42). That is, the electrode coupling portion (42) is positioned radially inward compared to the bridge (47), thereby securing a relatively wide can lid (40) area between the edge portion (41) and the electrode coupling portion (42).

[0130] In this manner, after the can lid (40) is hermetically coupled to the opening of the battery can (10), a filling material (100) can be applied to the vent portion (43) using a filling device (D). Here, the filling device (D) can be configured to precisely supply a liquid material by targeting a specific area of ​​the vent portion (43) from the outside of the battery can (10). Accordingly, the filling material (100) can be formed locally in the vulnerable area of ​​the vent portion (43) without diffusion to unnecessary areas. This method can be implemented through various liquid application processes such as dispensing, spraying, and inkjet, and the application location, amount of application, and shape of application can be precisely controlled through process control.

[0131] The filling member (100) can be formed by applying it in a liquid state to at least a portion of the outer surface of the vent portion (43) and then curing it. At this time, the filling member (100) can be applied locally and selectively along the indented shape formed in the vent portion (43), and can be formed intensively in the area of ​​the vent portion (43) where the metal layer is exposed or stress concentration is likely to occur. Accordingly, the maximum protective effect can be secured with the minimum amount of material, and corrosion from the external environment can be effectively suppressed while maintaining the original characteristics of the fracture area that performs the vent function.

[0132] The filling member (100) may include a silicone-based, urethane-based, or epoxy-based polymer. In some cases, a material such as a parting resin may be applied to the filling member (100). Such polymer-based materials provide excellent corrosion resistance and chemical resistance, and at the same time have excellent adhesion to metal surfaces, allowing them to remain stably attached to the surface of the vent portion (43). In addition, there is minimal change in physical properties even under temperature changes and electrolyte environments, which is advantageous for ensuring long-term reliability.

[0133] In particular, when selecting the filling material (100), various factors such as corrosion resistance, adhesion, effect on vent pressure, chemical resistance, unit cost, and tact time need to be comprehensively considered. For example, the filling material (100) should be designed so as not to delay the breakage of the vent portion (43) or change the vent opening pressure, and at the same time, it should be able to maintain sufficient adhesion to the metal surface without detachment for a long period. In addition, regarding the production process, materials and process conditions may be required so as not to excessively increase the coating and curing time, thereby not hindering manufacturing efficiency.

[0134] In this way, the external liquid application method using the filling device (D) enables precise and localized treatment of a specific area of ​​the vent portion (43), thereby effectively improving the durability and corrosion resistance of vulnerable parts while maintaining the functional characteristics of the vent structure. Consequently, the structure according to the present embodiment can provide a very useful technical means to simultaneously ensure the safety and reliability of the battery cell (1).

[0135]

[0136] FIG. 8 is a schematic diagram showing a battery cell (2) according to another embodiment of the present invention. The description of the battery cell (1) described above with reference to FIG. 1 to 7 can be applied in the same way to the battery cell (2) shown in FIG. 8, and redundant descriptions below will be omitted or simplified.

[0137] Referring to FIG. 8, the battery cell (2) may include a venting portion. The venting portion of the present embodiment may be a vent notch portion (17) formed on the battery can (10). For example, the vent notch portion (17) may be formed on the bottom member (12) of the battery can (10).

[0138] The vent notch portion (17) may be formed to have a closed-loop shape along the circumferential direction in one area of ​​the bottom member (12). Such a closed-loop structure allows for the rupture to be induced in a uniform and predictable manner along a specific path when the internal pressure of the battery rises, thereby enabling the internal pressure to be relieved stably while preventing sudden damage.

[0139] Additionally, the vent notch portion (17) is a notching structure formed by being recessed to a predetermined depth on the surface of the bottom member (12), and can form a point at which fracture begins by providing a weak area with reduced thickness. In particular, as the vent notch portion (17) is formed continuously along the circumferential direction, fracture can proceed uniformly without being concentrated locally, and thus stable behavior can be secured when the vent is opened.

[0140] Meanwhile, in this embodiment, to improve the corrosion resistance and durability of the vent notch portion (17), a filling member (100) may be formed in at least a portion of the vent notch portion (17). The filling member (100) may be arranged along the indented shape of the vent notch portion (17) and may be formed to fill at least a portion within the indented depth range. Accordingly, the filling member (100) may act as a protective layer that blocks contact with the external environment while substantially following the shape of the vent notch portion (17).

[0141] In particular, the filling member (100) may be formed locally in areas where the metal is exposed or susceptible to corrosion, rather than being formed over the entire area of ​​the vent notch (17). This allows for the effective suppression of corrosion caused by the external environment while maintaining the characteristics of the fracture path that directly contributes to the vent function. Additionally, the filling member (100) is formed so as not to exceed the depth of indentation of the vent notch (17), thereby preventing changes in the external shape or increase in height of the battery can (10) or minimizing such effects.

[0142] As a result, the battery cell (2) according to the present embodiment can effectively improve the corrosion resistance and durability of the vulnerable area by the locally formed filling member (100) without impairing the breaking function of the vent notch portion (17), and this can provide a very advantageous technical effect for a secondary battery requiring long-term reliability.

[0143]

[0144] FIG. 9 is a schematic diagram showing a battery pack (P) having battery cells (1, 2) according to one embodiment of the present invention, and FIG. 10 is a schematic diagram showing a vehicle (V) having a battery pack (P) according to one embodiment of the present invention.

[0145] Referring to FIG. 9, a battery pack (P) according to one embodiment of the present invention may include a pack housing (C) capable of accommodating a battery cell (1) of the present invention. A battery pack (P) according to one embodiment of the present invention may further include various other components of a battery pack known at the time of filing the present invention. For example, a battery pack (P) according to one embodiment of the present invention may further include components such as a current sensor, a fuse, and a service plug.

[0146] Referring to FIG. 10, a vehicle (V) according to one embodiment of the present invention may include one or more battery packs (P) according to the present invention. In addition, a vehicle (V) according to one embodiment of the present invention may include various other components included in the vehicle (V) in addition to the battery packs (P). For example, a vehicle (V) according to one embodiment of the present invention may include, in addition to the battery packs (P) according to one embodiment of the present invention, a vehicle body, a motor, an electronic control unit (ECU), or other control devices.

[0147] In addition, the battery pack (P) according to one embodiment of the present invention can be applied as various types of energy storage devices or power sources, and it is obvious that it may also be equipped in other devices, mechanisms, and facilities, such as an energy storage system using a secondary battery, in addition to the vehicle (V).

[0148] As described above, although the present invention has been explained 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.

[0149] [Explanation of Symbols] 1: Battery Cell

[0150] 10: Battery can

[0151] 11: Sidewall member

[0152] 12: Floor member

[0153] 13: Electrode terminal

[0154] 14: Terminal gasket

[0155] 15: Clerical Board

[0156] 16: Insulator

[0157] 17: Vent notch

[0158] 20: Electrode assembly

[0159] 21: First electrode

[0160] 22: Second electrode

[0161] 23: Metal foil

[0162] 24: Maintenance Department

[0163] 26: Mujibu

[0164] 27: Notching Tab

[0165] 28: Separator

[0166] 40: Can lid

[0167] 41: Edge part

[0168] 411: Butt joint

[0169] 412: Curved surface

[0170] 413: Slope

[0171] 42: Electrode coupling part

[0172] 43: Vent

[0173] 44: Injection point

[0174] 441: Settlement

[0175] 442: Insert

[0176] 45: Flat section

[0177] 46: Picking Department

[0178] 47: Bridge

[0179] 50: Plug

[0180] 100: Filling member

[0181] C: Pack case

[0182] D: Filling device

[0183] P: Battery pack

[0184] V: Car

Claims

1. A battery can having a side wall member, a bottom member connected to one axial end of the side wall member, and an opening provided at the other axial end of the side wall member; An electrode assembly received through the opening of the battery can, wherein the first electrode and the second electrode and the separator interposed between them are wound around a winding axis; and It includes a venting portion having a shape indented to a predetermined depth so as to be fractured by a predetermined pressure, A battery cell characterized in that a filling member is arranged along the indented shape of the venting portion, wherein the filling member is filled at least partially within the indented depth range.

2. In Paragraph 1, The above-mentioned filling member is, A battery cell characterized by being applied in a liquid state to at least a portion of the outer surface of the venting portion and then cured.

3. In Paragraph 1, The above-mentioned filling member is, A battery cell characterized by being locally and selectively applied along the indented shape of the venting portion.

4. In Paragraph 1, The above-mentioned filling member is, A battery cell characterized by comprising a silicon-based, urethane-based, or epoxy-based polymer.

5. In Paragraph 1, The above-mentioned filling member is, A battery cell characterized by being formed so as not to exceed the indentation depth of the venting portion.

6. In Paragraph 1, It further includes a can lid that covers the opening of the battery can, and The above venting part is, A battery cell characterized by including a vent portion having a closed-loop shape along the circumferential direction on the can lid.

7. In Paragraph 6, The above can lid is, It includes a first metal layer and a second metal layer formed on the first metal layer, The above vent part is, A battery cell characterized in that the second metal layer is removed to form an area in which the first metal layer is exposed, and the filling material is applied on at least one surface of the exposed first metal layer.

8. In Paragraph 7, The above-mentioned filling member is, A battery cell characterized by the first metal layer being formed to cover an exposed area to inhibit corrosion.

9. In Paragraph 7, The above-mentioned filling member is, A battery cell characterized by not being disposed on the second metal layer above.

10. In Paragraph 7, The first metal layer above includes nickel, and The above second metal layer contains iron, The above-mentioned filling member is, A battery cell characterized by being formed of a polymer.

11. In Paragraph 1, The above-mentioned filling member is, A battery cell characterized by being coated and cured in a closed-loop shape along the circumferential direction.

12. In Paragraph 1, The above venting part is, A battery cell characterized by including a bent notch portion having a closed-loop shape along the circumferential direction on the bottom member of the battery can.

13. In Paragraph 12, The above-mentioned bent notch portion is, A battery cell characterized by having the filling material locally and selectively applied on at least one surface.

14. As a battery pack, A battery pack characterized by including a battery cell according to any one of claims 1 to 13.

15. As a vehicle, A vehicle equipped with at least one battery pack according to Article 14.

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