Battery cell, and battery pack and vehicle including battery cell

Abstract

A battery cell of the present invention comprises: an electrode assembly in which a first electrode, a second electrode, and a separator therebetween are wound around a winding axis; a can configured to accommodate the electrode assembly through an open end portion formed at one side thereof; and a lid covering the open end portion, wherein the lid may comprise: an edge portion coupled to the can and having a protrusion forming a step; and a vent portion configured to break when a thermal event occurs in the battery cell, and including, on the basis of the circumferential direction of the lid, a first region in which a vulnerable portion is formed and a second region in which no vulnerable portion is formed.

Description

Battery cells, and battery packs containing these battery cells and automobiles

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

[0002] This application is a priority application for Korean Patent Application No. 10-2024-0175270 filed on November 29, 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 battery module or pack can be varied 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 covering the open end of the can with a lid to finish it. Seam welding or beading and crimping methods may be used for finishing.

[0009] Generally, when a thermal event occurs in a battery cell, the vent portion of the lead may rupture due to the internal pressure of the high-temperature venting gas. At this time, the lead may be separated based on the vent portion.

[0010] Additionally, the edge portion of the lid may be secured by the crimping portion of the can. However, if the vent pressure is high, the edge portion of the lid may not be secured and may separate from the can due to internal pressure, such as high-temperature venting gas.

[0011] In this case, at least a portion of the separated vent may remain inside the battery pack and move within the pack or collide with other components. In other words, the use and management of the battery pack may be difficult.

[0012] Therefore, there is a need to develop a battery cell structure in which the lead can remain secure and not be separated even if the vent portion of the lead is fractured.

[0013]

[0014] The present invention was conceived against the background of the prior art described above, and aims to provide a battery cell in which the lead is not separated even if the vent portion of the lead is fractured due to a thermal event occurring in the battery cell.

[0015] In addition, another technical objective of the present invention is to provide a battery cell in which the edge portion of the lead can be fixed without detaching from the can even by vent pressure when a thermal event occurs in the battery cell.

[0016] Another technical objective of the present invention is to provide a battery pack including a battery cell of an improved structure, and a vehicle including the battery pack.

[0017] 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 a person skilled in the art from the description of the invention below.

[0018]

[0019] To solve the above problem, the battery cell of the present invention comprises 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 can configured to accommodate the electrode assembly through an open end formed on one side, and a lead covering the open end, wherein the lead may include an edge portion coupled to the can and having a protrusion forming a step, and a vent portion configured to break upon the occurrence of a thermal event within the battery cell, and including a first region in which a weak portion is formed along the circumferential direction of the lead and a second region in which the weak portion is not formed.

[0020] The above lead may be characterized by being divided into an inner venting portion located on the inner side based on the radial direction of the vent portion and an outer venting portion located on the outer side based on the radial direction of the vent portion, and configured so as not to separate the inner venting portion and the outer venting portion when a thermal event occurs within the battery cell.

[0021] The above vent portion may be formed radially inward from the edge portion, and the first region may be formed by notching along the circumferential direction of the lead.

[0022] The first region of the above-mentioned vent portion may be characterized as having an arc shape formed along the circumferential direction of the lead.

[0023] The central angle of the first region of the above-mentioned vent portion may be formed as a first angle, and the first angle may be characterized as being 180 degrees or more and less than 360 degrees.

[0024] It may be characterized by including a gasket that ensures airtightness between the can and the lid and has a groove configured to allow the protrusion to be inserted.

[0025] The above gasket is positioned to cover the upper and lower surfaces of the lid, and the protrusion may be characterized by including a first protrusion protruding upward; and a second protrusion protruding downward.

[0026] The above can may be characterized by further having a stepped portion protruding toward the lid on one side facing the lid.

[0027] The above protrusion may be characterized as being in the shape of a ring having a constant width along the circumferential direction of the lead.

[0028] The above protrusion may be characterized as having an arc shape formed along the circumferential direction of the lead.

[0029] The above protrusion may be characterized by being formed only in the area corresponding to the first area based on the circumferential direction of the lead.

[0030] In addition, the present invention provides a battery pack characterized by including a battery according to the present invention.

[0031] And, the present invention provides an automobile characterized by including a battery pack according to the present invention.

[0032]

[0033] According to one embodiment of the present invention, a battery cell can be provided in which the lead may not be separated even if a thermal event occurs in the battery cell and the vent portion of the lead is fractured. Accordingly, the possibility of at least a portion of the separated lead moving inside the battery pack or colliding with other parts is reduced, the use and management of the battery pack are facilitated, and the stability of the battery cell and the battery pack can be improved.

[0034] In addition, according to one embodiment of the present invention, when a thermal event occurs in the battery cell, a battery cell can be provided in which the edge portion of the lid is fixed without detaching from the can even by vent pressure. That is, the phenomenon of the lid slipping off the can due to vent pressure can be prevented.

[0035] 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.

[0036]

[0037] 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.

[0038] FIG. 1 is a perspective view showing the appearance of a battery cell according to one embodiment of the present invention.

[0039] Figure 2 is a cross-sectional view of the battery cell of Figure 1 cut along the line A-A'.

[0040] FIG. 3 is a perspective view showing the appearance of a battery cell when a thermal event occurs in a battery cell according to one embodiment of the present invention.

[0041] FIG. 4 is a perspective view showing the outer surface of a lead according to one embodiment of the present invention.

[0042] FIG. 5 is a perspective view showing the outer surface of a lead that is broken by vent pressure at least partially when a thermal event occurs in a battery cell according to one embodiment of the present invention.

[0043] Figure 6 is a cross-sectional view of the lead of Figure 4 cut along B-B'.

[0044] Figure 7 is a cross-sectional view of the lead of Figure 4 cut along C-C'.

[0045] FIG. 8 is a perspective view showing the lower surface of a lead according to one embodiment of the present invention.

[0046] FIG. 9 is an enlarged view showing in detail a cross-section of a battery cell and a combined portion of a lead, gasket, and can according to one embodiment of the present invention.

[0047] FIG. 10 is an enlarged view showing in detail the joining portion of a lid, gasket, and can according to another embodiment of the present invention.

[0048] FIG. 11 is an enlarged view showing in detail the joining portion of a lid, gasket, and can according to another embodiment of the present invention.

[0049] FIG. 12 is a perspective view showing the inner surface of a lead according to another embodiment of the present invention.

[0050] Figure 13 is a drawing showing a cross-section of the lead of Figure 12 cut along the D-D' line.

[0051] FIG. 14 is a schematic diagram showing the configuration of a battery pack according to an embodiment of the present invention.

[0052] FIG. 15 is a drawing for explaining a vehicle including the battery pack of FIG. 14.

[0053]

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0064] For convenience of explanation, in this specification, the direction following the longitudinal direction of the winding axis of the electrode assembly (10) wound in a jelly roll shape is referred to as the axial direction (Y). The direction surrounding the winding axis is referred to as the circumferential direction or periphery direction (X). The direction approaching the winding axis or moving away from the winding axis is referred to as the radial direction or radial direction (Z). 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.

[0065] First, an electrode assembly (10) according to an embodiment of the present invention will be described. The electrode assembly (10) is a jellyroll type electrode assembly (10) having a structure in which an anode and a cathode having a sheet shape and a separator interposed between them are wound in one direction.

[0066] Preferably, at least one of the anode and the cathode includes an uncoated portion at the long end of the winding direction in which the active material is not coated. At least a portion of the uncoated portion can be used as an electrode tab itself.

[0067] FIG. 1 is a perspective view showing the exterior of a battery cell (1) according to one embodiment of the present invention. FIG. 2 is a cross-sectional view of the battery cell (1) of FIG. 1 taken along the line A-A'.

[0068] Referring to FIGS. 1 and 2, the battery cell (1) may include an electrode assembly (10), a can (20), and a lid (100). In addition to the components described above, the battery cell (1) may further include a first electrode terminal (40), an insulating gasket (50), a first current collector (60), an insulator (70), a second current collector (80), and / or a sealing gasket (90).

[0069] A battery cell (1) according to one embodiment of the present invention may be, for example, a cylindrical battery. Preferably, the battery cell (1) may be, for example, a cylindrical secondary battery with a form factor ratio (ratio of height to diameter) greater than approximately 0.4. Preferably, the diameter of the battery cell (1) may be 40 mm to 50 mm, and the height may be 60 mm to 130 mm. The form factor of the battery cell (1) may be, for example, 46110, 4875, 48110, 4880, or 4680. However, the present invention is not limited by the shape of the battery and is applicable to batteries of other shapes, such as prismatic batteries.

[0070] The electrode assembly (10) may be wound with respect to a winding axis, with the first electrode and the second electrode and the separator interposed between them. Referring to FIG. 2, the electrode assembly (10) may have a first unwound portion (11) and a second unwound portion (12). More specifically, the electrode assembly (10) may be in the form of a jelly-roll wound with the first electrode and the second electrode interposed between them and the separator interposed between them, centered on a winding axis. 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 (10) for insulation from the can (20). The structure of the electrode assembly (10) is not limited by the embodiment and may have a winding structure well known in the art.

[0071] The first electrode may be an anode plate and the second electrode may be a cathode plate. An anode active material may be coated on one or both sides of the anode plate, and a first uncoated portion (11) on which the anode active material is not coated may be formed at the end of the anode plate. The first uncoated portion (11) may be exposed to the outside of the separator while forming a plurality of wound turns based on the center of the electrode assembly (10), and may be used as an electrode tab itself. An anode active material may be coated on one or both sides of the cathode plate, and a second uncoated portion (12) on which the anode active material is not coated may be formed at the end of the cathode plate. The second uncoated portion (12) may be exposed to the outside of the separator while forming a plurality of wound turns based on the center of the electrode assembly (10), and may be used as an electrode tab itself.

[0072] That is, the positive plate and the negative plate may each include an uncoated portion along the winding direction at the long side end where the active material is not coated. Additionally, the first uncoated portion (11) and the second uncoated portion (12) may be configured to face in opposite directions. The first uncoated portion (11) may be housed inside the can (20) so as to be located at one end in the winding axis direction and the second uncoated portion (12) at the other end in the winding axis direction. 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.

[0073] 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.

[0074] 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.

[0075] For example, notches may be formed at predetermined intervals along the winding direction in the first blank section (11) and the second blank section (12) to form flag-shaped notching tabs. In the jelly-roll type electrode assembly (10), 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 (10). Alternatively, the notching tabs may be folded all at once after winding the laminate to form the jelly-roll type electrode assembly (10). The notching tabs of the first blank section (11) and the notching tabs of the second blank section (12), which are folded radially and stacked in this way, may each provide a plane that is substantially perpendicular to the axial direction at both axial ends of the electrode assembly (10).

[0076] A can (20) may be configured to accommodate an electrode assembly (10) through an open end formed on one side. The can (20) includes 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 bottom portion has a roughly flat shape. The side wall portion may be cylindrical, connected to the bottom portion, and extend axially. The side wall portion that is not connected to the bottom portion may define the open end of the can (20). The open end may be formed on the portion facing the bottom portion of the can (20). An electrode assembly (10) may be accommodated through the open end formed in the can (20). A lid (100) may be placed over the open end. In FIGS. 1 and 2, the bottom portion is shown as being included at the bottom of the can (20), and the open end is shown as being included at the top of the can (20).

[0077] The bottom and side wall portions can be manufactured by forming a metal sheet with nickel 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. Of course, the material of the can (20) is not limited to this. The material of the can (20) can be made of a conductive metal, such as aluminum, steel, stainless steel, etc., but is not limited to this.

[0078] Referring to FIGS. 1 and 2, the can (20) may have a beading portion (23) and a crimping portion (24) formed at the top. The beading portion (23) may be located on the upper part of the electrode assembly (10). The beading portion (23) may be formed by pressing the outer circumference of the can (20). Specifically, the beading portion (23) may have a shape that is pressed inward in the area between the open end formed on one side of the can (20) and the receiving portion that accommodates the electrode assembly (10). The beading portion (23) prevents the electrode assembly (10), which has a size approximately corresponding to the inner diameter of the can (20), from coming out through the open end formed at the top of the can (20), and may function as a support portion on which the lid (100) is seated.

[0079] The clamping portion (24) may be formed on the upper part of the beading portion (23). The clamping portion (24) may extend from the upper part of the beading portion (23). The clamping portion (24) may have an extended and bent shape to wrap around the outer surface of the lead (100) positioned on the upper part of the beading portion (23) and a portion of the upper surface of the lead (100). The clamping portion (24) may also secure a sealing gasket (90) in addition to the lead (100).

[0080] The lid (100) can be supported by the upper surface of the beading portion (23) formed on the can (20). Additionally, the lid (100) can be fixed by the clamping portion (24). That is, the lower surface of the lid (100) can be supported by the beading portion (23), and the outer surface and upper surface can be supported by the clamping portion (24). A sealing gasket (90) may be interposed between the lid (100) and the clamping portion (24) to ensure airtightness of the can (20).

[0081] However, the lead (100) may be joined to the can (20) using butt welding. That is, according to another embodiment, although not shown in the drawing, the can (20) may not have a beading portion (23) and / or a crimping portion (24). In this case, the battery cell (1) can have a larger internal capacity while maintaining the same external shape. Thus, the energy density can be increased.

[0082] The first electrode terminal (40) can be coupled to the bottom portion. The bottom portion forms the closed surface of the can (20). A through hole is formed in the bottom portion, and the first electrode terminal (40) can pass through the through hole. The first electrode terminal (40) may be fitted into the bottom portion. The first electrode terminal (40) may be riveted and fixed to the bottom portion with an insulating gasket (50) interposed therebetween. The insulating gasket (50) is interposed between the first electrode terminal (40) and the bottom portion to seal the inside and outside of the can (20) to prevent leakage of the electrolyte and to electrically insulate the first electrode terminal (40) and the bottom portion. The insulating gasket (50) may be in close contact between the first electrode terminal (40) and the can (20). A part of the first electrode terminal (40) is inserted inside the can (20), and another part is exposed outside the can (20).

[0083] The first electrode terminal (40) may be made of metal. The first electrode terminal (40) may be made of aluminum. During the process of riveting the first electrode terminal (40) to the can (20), the first electrode terminal (40) may be fixed on the outside of the can (20). The first electrode terminal (40) is electrically connected to the electrode assembly (10). The first electrode terminal (40) may be electrically connected to the first electrode of the electrode assembly (10) by passing through a through hole.

[0084] The battery cell (1) may further include a first current collector (60) configured to be electrically connected to a first electrode and a second current collector (80) configured to be electrically connected to a second electrode. The first current collector (60) may be electrically connected to a first electrode terminal (40). The second current collector (80) may be configured to be electrically connected to a can (20). The first current collector (60) and the second current collector (80) may each be joined to a substantially flat surface provided by bending notching tabs exposed at both ends of the winding axis direction of the electrode assembly (10). Thus, the first current collector (60) may be electrically connected to a first non-reinforced portion (11), and the second current collector (80) may be electrically connected to a second non-reinforced portion (12). Methods such as resistance welding, ultrasonic welding, or laser welding may be used for joining the parts.

[0085] Additionally, the battery cell (1) may further include an insulator (70). The insulator (70) may be provided between the first current collector (60) and the inner surface of the bottom portion. The insulator (70) prevents contact between the first current collector (60) and the can (20). The insulator (70) may also be interposed between the inner surface of the side wall portion and the electrode assembly (10). That is, the insulator (70) may also be interposed between the first non-contact portion (11) and the side wall of the can (20). This is to prevent contact between the first non-contact portion (11), which extends toward the bottom portion of the can (20), and the inner surface of the can (20).

[0086] The can (20) can be electrically connected to the second current collector (80). Accordingly, the first electrode terminal (40) may have a first polarity, and the can (20) may have a second polarity. In particular, the bottom portion of the can (20) and the side wall portion connected thereto may both have a second polarity. Accordingly, the can (20) may have both the first electrode terminal (40) and the second electrode terminal positioned at one end in the winding axis direction, for example, at the bottom portion. Then, the busbar connected to the first electrode terminal (40) and the busbar connected to the second electrode terminal may both be located at one end in the axial direction of the can (20). In one example, the first electrode terminal (40) may be a positive terminal and the second electrode terminal may be a negative terminal. Of course, the opposite may also be true. Accordingly, the battery cell (1) 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 (1). In addition, the battery cell (1) according to the present invention has the advantage of securing a sufficient area for welding components for electrical connection, as most of the bottom portion of the can (20) can be used as a second electrode terminal.

[0087] Below, the configuration and shape of the lead (100) will be described in detail.

[0088] FIG. 3 is a perspective view showing the appearance of a battery cell (1) when a thermal event occurs in the battery cell (1) according to an embodiment of the present invention. FIG. 4 is a perspective view showing the outer surface of a lead (100) according to an embodiment of the present invention. FIG. 5 is a perspective view showing the outer surface of a lead (100) in which at least a portion is broken by vent pressure when a thermal event occurs in the battery cell (1) according to an embodiment of the present invention. FIG. 6 is a cross-sectional view of the lead (100) of FIG. 4 cut along B-B'. FIG. 7 is a cross-sectional view of the lead (100) of FIG. 4 cut along C-C'.

[0089] The lid (100) may include an edge portion (110) that is coupled to the can (20) and a vent portion (120) configured to break when a thermal event occurs within the battery cell (1).

[0090] The edge portion (110) may be formed on the edge of the lid (100) so as to be coupled to the can (20). The edge portion (110) may be coupled by a press fit to an open end formed on one side of the can (20). The edge portion (110) may be coupled to the can (20) by welding after being press-fitted to one side of the can (20). The edge portion (110) may be positioned on the beading portion (23) and supported by the beading portion (23). The upper surface of the edge portion (110) may be supported by the clamping portion (24). That is, at least a portion of the edge portion (110) may be inserted and fixed within the space formed by the beading portion (23) and the clamping portion (24). The end of the edge portion (110) that is close to the electrode assembly (10) may be spaced apart from the electrode assembly (10).

[0091] The vent portion (120) can be ruptured 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. That is, the vent portion (120) can be ruptured when the pressure inside the can (20) exceeds a critical value. Since the battery cell (1) according to the present invention has the vent portion (120) provided in the lid (100) and does not occupy a separate space, it can secure a higher energy density.

[0092] The vent portion (120) may be formed radially inward from the edge portion (110). The vent portion (120) may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the lead (100). For example, the vent portion (120) may be formed in the shape of a roughly circular ring having a certain width. This circular ring-shaped vent portion (120) may have the same center as the center of the lead (100). When the vent portion (120) is formed on the lead (100), venting gas can be easily discharged from the battery cell (1). The thickness of the vent portion (120) may be formed thinner compared to other parts of the lead (100).

[0093] The lid (100) may be divided into a venting inner portion (103) located on the inner side based on the radial direction of the vent portion (120) and a venting outer portion (104) located on the outer side based on the radial direction of the vent portion (120). For example, the edge portion (110) may be located on the venting outer portion (104) of the lid (100).

[0094] Generally, when a thermal event occurs in the battery cell (1), the vent portion (120) of the lead (100) may be broken by the internal pressure of the high-temperature venting gas. In this case, since the venting outer portion (104) of the lead (100) is combined with the can (20), the venting inner portion (103) of the lead (100) may be separated from the venting outer portion (104) and remain inside the battery pack (battery pack (3) of FIG. 14). The venting inner portion (103) of the lead (100) remaining inside the battery pack (3) may move inside the battery pack (3) or collide with other parts, thereby contributing to the occurrence of a thermal event in the battery cell (1). That is, there may be inconvenience in terms of managing the battery cell (1) and the battery pack (3).

[0095] To solve such problems, the battery cell (1) according to the present invention may be configured so that the venting inner part (103) and the venting outer part (104) are not separated when a thermal event occurs within the battery cell (1). According to the present invention, only a part of the vent portion (120) may be configured as a vulnerable part so that at least a part is broken when a thermal event occurs. Therefore, the venting inner part (103) and the venting outer part (104) are not separated, and thus the inside of the battery pack (3) can be protected from the venting inner part (103).

[0096] Specifically, the vent portion (120) of the lead (100) may include a first region (121) in which a vulnerable portion is formed and a second region (122) in which a vulnerable portion is not formed, based on the circumferential direction of the lead (100).

[0097] According to one embodiment, a first region (121) of the vent portion (120) may be formed by notching along the circumferential direction of the lead (100). That is, the weak portion may be defined as a notched portion. The weak portion of the vent portion (120) may be formed on one or both sides of the lead (100). For example, the weak portion of the vent portion (120) may be formed on the upper surface (101) and / or lower surface (102) of the lead (100). For example, referring to FIG. 6, the vent portion (120) may be implemented as a thin-walled portion where both surfaces of the lead (100) are notched. For example, the weak portion may be defined as a portion that is thinner than other parts of the lead (100).

[0098] According to one embodiment, with reference to FIG. 4, the first region (121) of the vent portion (120) may be an arc shape formed along the circumferential direction of the lead (100). This arc-shaped first region (121) may have the same center as the center of the lead (100). However, the shape of the first region (121) is not limited by the embodiment and may be modified in various ways. That is, the weak portion of the first region (121) may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the lead (100).

[0099] The second region (122) may refer to an area excluding the first region (121) based on the circumferential direction of the lead (100). For example, referring to FIG. 7, the second region (122) is an area where no weak part is formed, and its thickness may be substantially the same as that of the other part of the lead (100). That is, since there is a second region (122) where no weak part is formed along the circumferential direction, the venting inner part (103) and the venting outer part (104) of the lead (100) may not be separated through the second region (122).

[0100] According to one embodiment, with reference to FIG. 4, the central angle of the first region (121) may be greater than the central angle of the second region (122). The central angle of the first region (121) of the vent portion (120) may be formed as a first angle (θ1). According to one embodiment, the first angle (θ1) may be an obtuse angle. The first angle (θ1) may be, for example, approximately 180 degrees or more and less than 360 degrees. The first angle (θ1) may be, for example, approximately 220 degrees or more and less than 360 degrees. The first angle (θ1) may be, for example, approximately 260 degrees or more and less than 360 degrees.

[0101] According to the present invention, the first region (121) that breaks can be formed larger than the second region (122) that does not break. Accordingly, when a thermal event occurs in the battery cell (1), if the first region (121) breaks, the venting inner part (103) of the lead (100) can be rotated relative to the second region (122) by the internal pressure of the venting gas. That is, the venting inner part (103) of the lead (100) can not obstruct the direction of travel of the venting gas, etc. Thus, the venting gas, etc. can be quickly discharged to the outside of the battery cell (1), while simultaneously preventing the lead (100) from being separated by the vent part (120).

[0102] FIG. 8 is a perspective view showing the lower surface (102) of a lead (100) according to one embodiment of the present invention. FIG. 9 is an enlarged view showing in detail the cross-section of a battery cell (1) according to one embodiment of the present invention and the combined portion of the lead (100), sealing gasket (90), and can (20).

[0103] The edge portion (110) may further include a protrusion (111) forming a step. According to one embodiment, the protrusion (111) may be formed on the lower surface (102) of the lead (100). The protrusion (111) may protrude inwardly into the battery cell (1). According to FIG. 9, the protrusion (111) may protrude downwardly into the battery cell (1). However, according to FIG. 8, since the lower surface (102) of the lead (100) is shown, the protrusion (111) may protrude upwardly.

[0104] The protrusion (111) may be in the shape of a ring having a constant width along the circumferential direction of the lead (100). The protrusion (111) may be formed along the edge portion (110) on the edge portion of the lead (100). This circular ring-shaped protrusion (111) may have the same center as the center of the lead (100). However, the shape of the protrusion (111) is not limited by the embodiment and may be modified in various ways. That is, the protrusion (111) may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the lead (100).

[0105] For example, referring to FIG. 9, the cross-section of the protrusion (111) may be rectangular. However, the shape of the cross-section of the protrusion (111) is not limited by the embodiment and can be designed in various ways as long as it is a protruding structure.

[0106] Another battery cell (1) of the present invention may further include a gasket (e.g., a sealing gasket (90)). The sealing gasket (90) may be formed between the can (20) and the lid (100). The sealing gasket (90) may be provided to ensure airtightness of the can (20) between the lid (100) and the clamping portion (24) of the can (20). The sealing gasket (90) may be in contact with the inner surface of the clamping portion (24).

[0107] Referring to FIG. 9, the sealing gasket (90) may have a groove (91) configured to receive a protrusion (111). The groove (91) may be recessed inward toward the battery cell (1). According to FIG. 9, the groove (91) may be indented downward. The shape of the groove (91) may be substantially the same as the shape of the protrusion (111). For example, the cross-section of the groove (91) may be rectangular. Thus, the protrusion (111) of the lid (100) may be engaged with the groove (91) of the sealing gasket (90).

[0108] The sealing gasket (90) may be positioned to cover the upper surface (101) and lower surface (102) of the lid (100). For example, the sealing gasket (90) may be joined to the inner surface of the clamping portion (24) at least three times. Thus, as the can (20) and the lid (100) are joined, the sealing gasket (90) may come into contact with the edge portion (110) of the lid (100) at least three times. The cross-section of the sealing gasket (90) may be a 'C' shape recessed radially outward along the shape of the clamping portion (24) of the battery cell (1). The sealing gasket (90) may be a ring shape having a constant width along the inner surface of the clamping portion (24).

[0109] According to an embodiment of the present invention, a protrusion (111) is positioned on the front of the lid (100) along the circumferential direction, thereby completely preventing the lid (100) from slipping from the upper end of the can (20) (e.g., the clamping portion (24)). Additionally, the bonding force between the sealing gasket (90) and the lid (100) is further strengthened by the first groove (91b) formed in the sealing gasket (90), thereby preventing the lid (100) from slipping and detaching from the can (20) due to vent pressure. Thus, it is possible to prevent the lid (100) from detaching from the battery cell (1) and colliding with other parts within the battery pack (3). That is, even if a thermal event occurs in the battery cell (1), the lid (100) can remain fixed to the battery cell (1).

[0110] FIG. 10 is an enlarged view showing in detail the combined portion of a lid (100), a sealing gasket (90), and a can (20) according to another embodiment of the present invention.

[0111] The protrusion (111) may include a first protrusion (111b) protruding upward and a second protrusion (111a) protruding downward. The protrusion (111) may include at least one of the first protrusion (111b) or the second protrusion (111a). The second protrusion (111a) of FIG. 10 may be substantially the same as the protrusion (111) of FIG. 8 and FIG. 9.

[0112] The first protrusion (111b) may be formed on the upper surface (101) of the lead (100). The first protrusion (111b) may protrude outwardly from the battery cell (1). According to FIG. 10, the protrusion (111) may protrude upwardly.

[0113] The first protrusion (111b) may be in the shape of a ring having a constant width along the circumferential direction of the lead (100). The first protrusion (111b) may be formed along the edge portion (110) at the edge portion of the lead (100). This circular ring-shaped first protrusion (111b) may have the same center as the center of the lead (100). However, the shape of the first protrusion (111b) is not limited by the embodiment and may be designed in various ways. That is, the first protrusion (111b) may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the lead (100). The shape and structure of the first protrusion (111b) may not correspond to the shape and structure of the second protrusion (111a).

[0114] The sealing gasket (90) may have a first groove (91b) configured to receive a first protrusion (111b) and a second groove (91a) configured to receive a second protrusion (111a). The second groove (91a) of FIG. 10 may be substantially the same as the groove (91) of FIG. 8 and FIG. 9.

[0115] The first groove (91b) may be recessed in the outward direction of the battery cell (1). According to FIG. 10, the first groove (91b) may be indented in the upward direction. The shape of the first groove (91b) may be substantially the same as the shape of the first protrusion (111b). For example, the cross-section of the first groove (91b) may be rectangular. Thus, the first protrusion (111b) of the lead (100) and the first groove (91b) of the sealing gasket (90) can be joined in an interlocking manner.

[0116] According to an embodiment of the present invention, the contact area between the protrusion (111) and the sealing gasket (90) is increased to further strengthen the bonding force between the sealing gasket (90) and the lid (100), thereby effectively preventing the lid (100) from slipping and detaching from the can (20) due to vent pressure. Therefore, it is possible to prevent the lid (100) from detaching from the battery cell (1) and colliding with other parts within the battery pack (3). That is, even if a thermal event occurs in the battery cell (1), the lid (100) can remain fixed to the battery cell (1).

[0117] FIG. 11 is an enlarged view showing in detail the combined portion of a lid (100), a sealing gasket (90), and a can (20) according to another embodiment of the present invention. The configuration of FIG. 11 may be all or partly the same as the configuration of FIG. 10.

[0118] The can (20) may further include a stepped portion (25) protruding toward the lid (100) on one side facing the lid (100). The stepped portion (25) may be formed on one side facing the upper surface (101) of the lid (100) of the can (20). The stepped portion (25) may be formed on one side of a clamping portion (24) covering the upper surface (101) of the lid (100). The stepped portion (25) may protrude inward toward the battery cell (1). Referring to FIG. 11, the stepped portion (25) may protrude downward.

[0119] According to an embodiment of the present invention, when a thermal event occurs in the battery cell (1), even if the lead (100) slips from the sealing gasket (90), the protrusion (111) formed on the edge portion (110) of the lead (100) (substantially identical to the second protrusion (111a) of FIG. 10) can catch on the stepped portion (25) of the can (20). Thus, the lead (100) can be effectively prevented from detaching from the battery cell (1).

[0120] FIG. 12 is a perspective view showing the inner surface of a lead (100) according to another embodiment of the present invention. FIG. 13 is a cross-sectional view of the lead (100) of FIG. 12 cut along the D-D' line.

[0121] The protrusion (111) may be formed in at least some area based on the circumferential direction of the lead (100).

[0122] According to one embodiment, the protrusion (111) may be formed only in the area corresponding to the first region (121) with respect to the circumferential direction of the lead (100). That is, the protrusion (111) may not be formed in the second region (122). In other words, the protrusion (111) may be formed in the first region (121) where the vulnerable part is formed, and the protrusion (111) may not be formed in the second region (122) where the vulnerable part is not formed.

[0123] The protrusion (111) may be an arc shape formed along the circumferential direction of the lead (100). This arc-shaped protrusion (111) may have the same center as the center of the lead (100). However, the shape of the protrusion (111) is not limited by the embodiment and may be modified in various ways. That is, the protrusion (111) may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the lead (100).

[0124] The central angle of the protrusion (111) may be substantially the same as the central angle of the first region (121) of the vent portion (120). Thus, the central angle of the protrusion (111) may be formed as a first angle (θ1). According to one embodiment, the first angle (θ1) may be an obtuse angle. The first angle (θ1) may be, for example, approximately 180 degrees or more and less than 360 degrees. The first angle (θ1) may be, for example, approximately 220 degrees or more and less than 360 degrees. The first angle (θ1) may be, for example, approximately 260 degrees or more and less than 360 degrees.

[0125] The shape and structure of the groove (91) formed in the sealing gasket (90) may correspond to the shape and structure of the protrusion (111). That is, the groove (91) may be formed only in the area corresponding to the area where the protrusion (111) is formed, based on the circumferential direction of the can (20). The groove (91) may be an arc shape formed along the circumferential direction of the can (20).

[0126] According to an embodiment of the present invention, even if the protrusion (111) formed on the lid (100) is formed only in at least a portion of the lid (100), the lid (100) and the can (20) may not be separated. Therefore, this may be advantageous in terms of manufacturing costs. Additionally, since the first region (121) is a region where the weak part is directly fractured by vent pressure, it may be a part where a stronger pressure acts than on the second region (122). By forming the protrusion (111) and the groove (91) limited to the first region (121), the can (20) and the lid (100) may not be separated from the stronger internal pressure.

[0127] FIG. 14 is a drawing for explaining a battery pack (3) according to an embodiment of the present invention. FIG. 15 is a drawing for explaining a vehicle including the battery pack (3) of FIG. 14.

[0128] Referring to FIG. 14, the battery pack (3) according to the present invention may include at least one battery cell (1) according to the present invention as described above. Additionally, the battery pack (3) according to the present invention may include a pack housing (2) capable of accommodating at least one battery cell (1). The battery pack (3) may be constructed using a battery module, which is an intermediate form of assembly, or the battery pack (3) may be constructed directly without a battery module as illustrated. For example, the battery pack (3) of the present invention may be manufactured by a cell-to-pack process.

[0129] In addition, the battery pack (3) may further include various other components in addition to the battery cell (1), such as a BMS, a pack case, a relay, a current sensor, etc., components of the battery pack (3) known at the time of filing the present invention.

[0130] A battery pack (3) may include a plurality of battery cells (1). The battery cells (1) may be arranged in a predetermined number of rows, and may be arranged so that a first electrode terminal (40) having a first polarity and a second electrode terminal having a second polarity are both positioned on the upper side of each battery cell (1). Accordingly, when electrically connecting a plurality of battery cells (1), both positive and negative electrodes can be connected in one direction, thereby simplifying the electrical connection structure. Through this, the number of battery cells (1) 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 (3). Additionally, as previously explained, each battery cell (1) may have a higher energy density than conventional ones. A battery pack (3) with such increased energy density can store the same amount of energy while reducing its volume and load.

[0131] Therefore, if a battery pack (3) with such battery cells (1) is installed in a vehicle such as a car (V) that uses electricity as an energy source as shown in FIG. 15, the vehicle's mileage relative to energy can be further increased.

[0132] In addition, since electrical wiring is performed on the side where the bottom of the can (20) and the electrode terminal (210) are located, and electrical wiring may not be placed on the lead (100) located on the opposite side, the effect of the vent can be maximized if a vent portion (120) is configured on the lead (100) so that it can be vented toward the lead (100). Also, if a heat sink, cooling plate, or tray is placed on the side of the lead (100), the purpose of assembly and cooling can be effectively achieved regardless of the electrical wiring connection point. Furthermore, by assembling the vent portion (120) 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 (1) 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 (120) breaks and does not cause harm to the occupant, the safety is greatly improved.

[0133] Referring to FIG. 14, the automobile (V) according to the present invention may include at least one battery pack (3) according to the present invention.

[0134] The battery cell (1) according to the present invention can be applied to a vehicle such as an electric vehicle or a hybrid vehicle. That is, the vehicle (V) according to the present invention may include the battery cell (1) according to the present invention or the battery pack (3) according to the present invention. In addition, the vehicle (V) according to the present invention may further include various other components included in the vehicle in addition to the battery cell (1) or the battery pack (3). For example, the vehicle (V) 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 (1) according to the present invention. The vehicle (V) includes four-wheeled vehicles and two-wheeled vehicles. The vehicle (V) may operate by receiving power from the battery pack (3) according to one embodiment of the present invention.

[0135] 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 can configured to accommodate the electrode assembly through an open end formed on one side; and A lead covering the above-mentioned open end; comprising The above lead is, An edge portion combined with the above-mentioned can and having a protrusion forming a step; and A battery cell characterized by comprising: a vent portion configured to break upon the occurrence of a thermal event within the battery cell, and including a first region in which a weak portion is formed with respect to the circumferential direction of the lead and a second region in which the weak portion is not formed.

2. In Paragraph 1, The above lead is An inner venting portion located on the inner side based on the radial direction of the above-mentioned vent portion; and Divided into a venting outer part located on the outer side based on the radial direction of the above vent part; A battery cell characterized by being configured so that the inner venting portion and the outer venting portion are not separated when a thermal event occurs within the battery cell.

3. In Paragraph 1, A battery cell characterized in that the vent portion is formed radially inward from the edge portion, and the first region is formed by notching along the circumferential direction of the lead.

4. In Paragraph 1, A battery cell characterized in that the first region of the above-mentioned vent portion is an arc shape formed along the circumferential direction of the lead.

5. In Paragraph 1, The central angle of the first region of the above-mentioned vent portion is formed as a first angle, and A battery cell characterized in that the first angle is 180 degrees or more and less than 360 degrees.

6. In Paragraph 1, A battery cell characterized by including a gasket that ensures airtightness between the can and the lid and has a groove configured to allow the protrusion to be inserted.

7. In Paragraph 6, The above gasket is positioned to cover the upper and lower surfaces of the above lead, and A battery cell characterized by the above-mentioned protrusions comprising: a first protrusion protruding upward; and a second protrusion protruding downward.

8. In Paragraph 1, A battery cell characterized in that the above-mentioned can further comprises a stepped portion protruding toward the lid on one side facing the lid.

9. In Paragraph 1, A battery cell characterized in that the above-mentioned protrusion is in the shape of a ring having a constant width along the circumferential direction of the above-mentioned lead.

10. In Paragraph 1, A battery cell characterized in that the above-mentioned protrusion is an arc shape formed along the circumferential direction of the lead.

11. In Paragraph 1, A battery cell characterized in that the above-mentioned protrusion is formed only in the area corresponding to the first region based on the circumferential direction of the lead.

12. A battery pack characterized by comprising at least one battery cell described in any one of claims 1 to 11.

13. An automobile characterized by comprising at least one battery cell described in any one of claims 1 to 11.

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