Battery cell, and battery pack and automobile including battery cell

Abstract

A battery cell according to the present invention may comprise: an electrode assembly in which a first electrode, a second electrode, and a separator located therebetween are wound around a winding shaft; a can that includes a sidewall portion, a bottom portion connected to one end of the sidewall portion in the direction of the winding shaft, and an open end provided at the other end of the sidewall portion in the direction of the winding shaft, wherein the can is configured to accommodate the electrode assembly via the open end; a first current collector configured to be electrically connected to the first electrode and including a first vent portion configured to rupture when a thermal event occurs in the battery cell; and a first electrode terminal that covers a through-hole formed in the bottom portion and is configured to be electrically connected to the first current collector.

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. 10-2024-0188974 filed on December 17, 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 portion (closed surface) and a circular tubular side wall portion connected thereto, accommodating an electrode assembly inside the can, and then covering the open end of the can with a lid to finish it.

[0009] Generally, when a thermal event occurs in a battery cell, the vent portion of the lead may be ruptured by the internal pressure of the high-temperature venting gas. However, if a cooling module, etc. is positioned at the bottom of the battery cell, i.e., facing the lead, it may be difficult to form a vent portion in the lead.

[0010] Therefore, there is a need to develop a battery cell structure that allows the electrode assembly to be easily ejected even when the positive current collector plate and / or the bottom of the can located opposite the lead is fractured, rather than the lead being fractured.

[0011]

[0012] The present invention was conceived against the background of the prior art described above, and aims to provide a battery cell configured such that, when a thermal event occurs in the battery cell, the positive current collector plate and the bottom part of the can are fractured, allowing the electrode assembly to be easily discharged.

[0013] In addition, the invention provides a battery cell capable of preventing thermal runaway caused by the transfer of flame to adjacent battery cells, a battery pack including the same, and a vehicle.

[0014] In addition, through this, the invention provides a battery cell capable of improving the stability of the battery cell, a battery pack including the same, and a vehicle.

[0015] 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.

[0016]

[0017] To solve the above problem, the battery cell of the present invention may include an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound along a winding axis, a side wall portion, a bottom portion connected to one end of the side wall portion in the direction of the winding axis, and an open end formed at the other end of the side wall portion in the direction of the winding axis, and a can configured to accommodate the electrode assembly through the open end, a first current collector configured to be electrically connected to the first electrode and configured to break when a thermal event occurs within the battery cell, and a first electrode terminal configured to cover a through hole formed in the bottom portion and electrically connected to the first current collector.

[0018] The first current collector may be configured such that, when a thermal event occurs within the battery cell, the first vent portion is broken, thereby forming a first venting hole surrounded by the first vent portion.

[0019] The above first vent portion may be formed by notching.

[0020] The first vent portion may be a ring shape formed along the circumferential direction.

[0021] The above bottom portion may have a second vent portion configured to break when a thermal event occurs within the battery cell.

[0022] The first electrode terminal may be located on the radially inner side of the second vent portion.

[0023] The diameter of the second vent portion may be larger than the diameter of the first vent portion.

[0024] When a thermal event occurs within the battery cell, the second vent portion may be ruptured, and a second venting hole surrounded by the second vent portion may be formed.

[0025] It may further include an insulator having a third vent portion located between the can and the first current collector and configured to break when a thermal event occurs within the battery cell.

[0026] The diameter of the third vent portion may be smaller than the diameter of the second vent portion.

[0027] The first current collector may further include a non-bonded portion coupling portion which is coupled to the non-bonded portion of the first electrode, and a terminal coupling portion which is coupled to the first electrode terminal, and a weld portion configured to be welded to the non-bonded portion at the non-bonded portion coupling portion may be arranged to be spaced apart from the first vent portion.

[0028] In addition, the present invention provides a battery pack characterized by including a battery according to the present invention.

[0029] And, the present invention provides an automobile characterized by including a battery pack according to the present invention.

[0030]

[0031] According to one embodiment of the present invention, a battery cell is provided that is configured such that when a thermal event occurs in the battery cell, the positive current collector plate and the bottom of the can are fractured, allowing the electrode assembly to be easily discharged. Accordingly, the electrode remaining in the battery cell is minimized, and the residual heat capacity is minimized, thereby preventing heat transfer to adjacent battery cells.

[0032] In addition, this has the effect of preventing thermal runaway caused by flames being transferred to adjacent battery cells.

[0033] In addition, this has the effect of improving the stability of the battery cell.

[0034] 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.

[0035]

[0036] 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.

[0037] FIG. 1 is a perspective view showing the appearance of a battery cell according to one embodiment of the present invention.

[0038] Figure 2 is a cross-sectional perspective view of the battery cell of Figure 1 cut along II-II'.

[0039] Figure 3 is a cross-sectional view of the battery cell of Figure 1 cut along II-II'.

[0040] Figure 4 is an enlarged view of part A of Figure 3.

[0041] FIG. 5 is a drawing showing a battery cell according to one embodiment of the present invention as viewed from the upper direction.

[0042] FIG. 6 is a drawing illustrating the appearance of a can and a first current collector being broken when a thermal event occurs in a battery cell according to an embodiment of the present invention.

[0043] FIG. 7 is an enlarged view of part A of FIG. 3 according to another embodiment of the present invention.

[0044] FIG. 8 is a drawing showing a battery cell according to another embodiment of the present invention as viewed from the upper direction.

[0045] FIG. 9 is a drawing illustrating the fracture of the can, the first current collector, and the insulator when a thermal event occurs in a battery cell according to another embodiment of the present invention.

[0046] FIG. 10 is a plan view of the first current collector in another embodiment of the present invention.

[0047] FIG. 11 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0048] FIG. 12 is a drawing for explaining a vehicle including the battery pack of FIG. 11.

[0049]

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] First, an electrode assembly (10) according to an embodiment of the present invention will be described. The electrode assembly (10) may have a structure in which an anode and a cathode having a sheet shape and a separator interposed between them are wound in one direction. The electrode assembly (10) may be, for example, a jelly roll type electrode assembly (10).

[0062] 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.

[0063] 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 perspective view of the battery cell (1) of FIG. 1 taken along II-II'. FIG. 3 is a cross-sectional view of the battery cell (1) of FIG. 1 taken along II-II'.

[0064] Referring to FIGS. 1 and 2, the battery cell (1) may include an electrode assembly (10), a can (20), a first current collector (30), and a first electrode terminal (40). In addition to the components described above, the battery cell (1) may additionally include at least one of an insulating gasket (50), a lead (60), an insulator (70), and a second current collector (80).

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] For example, the first blank portion (11) and the second blank portion (12) may form notches at predetermined intervals along the winding direction 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 portion (11) and the notching tabs of the second blank portion (12), which are folded radially and overlapped in this way, may each provide a plane that is substantially perpendicular to the axial direction at both axial ends of the electrode assembly (10).

[0072] A can (20) may be configured to accommodate an electrode assembly (10) through an open end formed on one side. The can (20) may include a side wall portion (21), a bottom portion (22) connected to one axial end of the side wall portion (21), and an open end provided at the other axial end of the side wall portion (21). The bottom portion (22) may have a roughly flat shape. The side wall portion (21) may be cylindrical, connected to the bottom portion (22), and may extend axially. The side of the side wall portion (21) that is not connected to the bottom portion (22) may be defined as the open end of the can (20).

[0073] In FIGS. 1 and 2, the bottom portion (22) is shown as being included at the top of the can (20), and the open end is shown as being included at the bottom of the can (20). The open end may be formed in a portion facing the bottom portion (22) of the can (20). An electrode assembly (10) may be received through the open end formed in the can (20). A lid (60) may be covered over the open end.

[0074] The bottom portion (22) and the side wall portion (21) 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 front end of the side wall portion (21) with a punch while holding it with a blank holder. For example, the material of the can (20) can be made of a conductive metal, such as aluminum, steel, stainless steel, etc. However, the material of the can (20) is not limited to this and can be designed and modified in various ways.

[0075] The first electrode terminal (40) can be coupled with the bottom portion (22). The bottom portion (22) forms the closed surface of the can (20). A through hole is formed in the bottom portion (22), and the first electrode terminal (40) can pass through the through hole. The first electrode terminal (40) may be fitted into the bottom portion (22). The first electrode terminal (40) may be fixed by riveting to the bottom portion (22) with an insulating gasket (50) interposed therebetween. The insulating gasket (50) is interposed between the first electrode terminal (40) and the bottom portion (22) 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 (22). The insulating gasket (50) may be in close contact between the first electrode terminal (40) and the can (20). A portion of the first electrode terminal (40) is inserted inside the can (20), and another portion may be exposed outside 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.

[0076] The battery cell (1) may further include a first current collector (30) 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 (30) 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 (30) 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 (30) 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.

[0077] Additionally, the battery cell (1) may further include an insulator (70). The insulator (70) may be located between the first current collector (30) and the can (20). The insulator (70) may be provided between the first current collector (30) and the inner surface of the bottom portion (22). The insulator (70) may prevent contact between the first current collector (30) and the can (20). The insulator (70) may also be interposed between the inner surface of the side wall portion (21) 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 (22) of the can (20), and the inner surface of the can (20).

[0078] 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 (22) of the can (20) and the side wall portion (21) 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 (25) positioned at one end in the winding axis direction, for example, at the bottom portion (22). Then, the bus bar connected to the first electrode terminal (40) and the bus bar connected to the second electrode terminal (25) 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 (25) may be a negative terminal. Of course, the opposite may also be true. Therefore, 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 surface area for welding components for electrical connection, as most of the bottom portion (22) of the can (20) can be used as a second electrode terminal (25).

[0079] Referring to FIGS. 1 to 3, the present invention can induce the electrode assembly (10) to be discharged in an upward direction when a thermal event occurs in the battery cell (1). The present invention may further provide at least one vent portion (e.g., a first vent portion (V1), a second vent portion (V2)) located on the upper side of the electrode assembly (10). This will be described in detail below.

[0080] FIG. 4 is an enlarged view of part A of FIG. 3. FIG. 5 is a drawing showing a battery cell (1) according to an embodiment of the present invention viewed from an upward direction. FIG. 6 is a drawing showing the can (20) and the first current collector (30) broken when a thermal event occurs in the battery cell (1) according to an embodiment of the present invention. When referring to FIG. 5, the first vent part (V1) and the second vent part (V2) are not visible from the upper side of the battery cell (1), but for convenience of explanation, they are indicated and described.

[0081] The first current collector (30) may be configured to be electrically connected to the first electrode. The first current collector (30) may be provided with a first vent portion (V1). The first vent portion (V1) may be configured to rupture due to the internal pressure of high-temperature venting gas when a thermal event occurs within the battery cell (1). That is, the first vent portion (V1) may rupture when the pressure inside the can (20) exceeds a critical value. Accordingly, the venting gas formed within the battery cell (1) may be discharged from the battery cell (1) to the outside.

[0082] When a thermal event occurs within the battery cell (1), the electrode assembly (10) can be induced to be discharged to the outside of the battery cell (1) in order to minimize the electrode remaining within the battery cell (1). At this time, the electrode assembly (10) can be discharged in the upward direction where the first current collector (30) is located. However, generally, the upper side of the electrode assembly (10) is covered by the first current collector (30), so that the first current collector (30) may obstruct the discharge of the electrode assembly (10).

[0083] According to an embodiment of the present invention, when a thermal event occurs within the battery cell (1), the first vent portion (V1) formed in the first current collector (30) ruptures, and the electrode assembly (10) can be discharged to the outside of the battery cell (1). Thus, when a thermal event occurs within the battery cell (1), the electrode assembly (10) can be discharged to the upper side of the battery cell (1). In addition, since the battery cell (1) does not need to provide a separate venting space by providing the first vent portion (V1) in the first current collector (30), it is possible to secure a higher energy density.

[0084] In other words, when a thermal event occurs within the battery cell (1), the first vent portion (V1) is broken, and a first venting hole (31) can be formed in the first current collector (30). The first venting hole (31) of the first current collector (30) can be surrounded by the first vent portion (V1). The first venting hole (31) can be formed radially inward of the first vent portion (V1). Accordingly, when a thermal event occurs within the battery cell (1), the electrode assembly (10) can pass through the first venting hole (31) and be discharged to the outside of the battery cell (1).

[0085] The first vent portion (V1) may be formed by notching. The first vent portion (V1) may be formed by notching along the circumferential direction. The thickness of the first vent portion (V1) may be formed thinner compared to other areas of the first current collector (30). The first vent portion (V1) may be formed on one or both sides of the first current collector (30). For example, the first vent portion (V1) may be formed on the upper surface and / or lower surface of the first current collector (30). For example, the first vent portion (V1) may be implemented as a thin-walled portion formed by notching both surfaces of the first current collector (30).

[0086] According to an embodiment of the present invention, the first vent portion (V1) is formed thinner compared to the surrounding area, so it can be broken more easily than the surrounding area. That is, when the pressure inside the can (20) increases above a certain level, the first vent portion (V1) breaks, allowing the gas and / or electrode assembly (10) generated inside the can (20) to be discharged more easily.

[0087] According to one embodiment, the first vent portion (V1) may have a closed-loop shape. A portion located radially inside the first vent portion (V1) in the first current collector (30) and surrounded by the first vent portion (V1) can be separated from other parts of the first current collector (30) and discharged to the outside of the battery cell (1) simultaneously with the breaking of the first vent portion (V1). Thus, the electrode assembly (10) can be discharged more easily to the outside of the battery cell (1). However, the shape of the first vent portion (V1) is not limited by the above embodiment. According to another embodiment, although not shown in the drawings, the first vent portion (V1) may not form a closed loop so that the first current collector (30) is not separated even if the first vent portion (V1) breaks. Therefore, a part of the first current collector (30) is separated and moves around inside the battery pack (3), thereby minimizing the problem of difficult management of the battery pack (3).

[0088] According to one embodiment, the first vent portion (V1) may be a ring shape formed along the circumferential direction. This circular ring-shaped first vent portion (V1) may have the same center as the center of the first current collector (30). However, the shape of the first vent portion (V1) is not limited by the embodiment and may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the first current collector (30).

[0089] The bottom portion (22) of the can (20) may be provided with a second vent portion (V2). Both the first current collector (30) and the can (20) may be configured so that the second vent portion (V2) ruptures when a thermal event occurs within the battery cell (1). That is, the second vent portion (V2) may rupture when the pressure inside the can (20) exceeds a critical value. Accordingly, the venting gas formed within the battery cell (1) can be easily discharged from the battery cell (1) to the outside.

[0090] When a thermal event occurs within the battery cell (1), the electrode assembly (10) and the first current collector (30) may be configured to be discharged to the outside of the battery cell (1) through the second vent (V2). That is, not only the electrode assembly (10) but also the first current collector (30) may be discharged upward through the second vent (V2).

[0091] According to an embodiment of the present invention, when a thermal event occurs within the battery cell (1), the first vent portion (V1) formed in the first current collector (30) and the second vent portion (V2) formed in the bottom portion (22) of the can (20) may rupture sequentially or simultaneously. Additionally, the electrode assembly (10) may be discharged to the outside of the battery cell (1) by penetrating the first current collector (30) and the can (20).

[0092] Thus, when a thermal event occurs within the battery cell (1), the electrode assembly (10) and the first current collector (30) can be discharged to the upper side of the battery cell (1). By discharging the first current collector (30) and the electrode assembly (10) together to the outside of the battery cell (1), the electrode remaining inside the battery cell (1) can be further minimized, and heat transfer to adjacent battery cells (1) can be prevented more efficiently.

[0093] In other words, when a thermal event occurs within the battery cell (1), the second vent portion (V2) is broken, and a second venting hole (23) may be formed in the bottom portion (22) of the can (20). The second venting hole (23) may be surrounded by the second vent portion (V2). The second venting hole (23) may be formed radially inward of the second vent portion (V2). Accordingly, when a thermal event occurs within the battery cell (1), the electrode assembly (10) may be discharged to the outside of the battery cell (1) by passing through the first venting hole (31) and the second venting hole (23).

[0094] The second vent portion (V2) may be formed by notching. The second vent portion (V2) may be formed by notching along the circumferential direction. The thickness of the second vent portion (V2) may be formed thinner compared to other areas of the can (20). The second vent portion (V2) may be formed on one or both sides of the bottom portion (22) of the can (20). For example, the second vent portion (V2) may be formed on the upper and / or lower surface of the bottom portion (22). For example, the second vent portion (V2) may be implemented as a thin-walled portion with notching on both surfaces of the bottom portion (22).

[0095] According to an embodiment of the present invention, the second vent portion (V2) is formed thinner compared to the surrounding area, so it can be broken more easily than the surrounding area. That is, when the pressure inside the can (20) increases above a certain level, the second vent portion (V2) breaks, and the gas or electrode assembly (10) generated inside the can (20) can be discharged.

[0096] According to one embodiment, the second vent portion (V2) may have a closed-loop shape. A portion located radially inside the second vent portion (V2) from the bottom portion (22) and surrounded by the second vent portion (V2) can be separated from other parts of the bottom portion (22) and discharged to the outside of the battery cell (1) simultaneously with the breaking of the second vent portion (V2). Thus, the electrode assembly (10) can be discharged more easily to the outside of the battery cell (1). However, the shape of the second vent portion (V2) is not limited by the above embodiment. According to another embodiment, although not shown in the drawings, the second vent portion (V2) may not form a closed loop so that the bottom portion (22) does not separate even if the second vent portion (V2) breaks. Thus, a portion of the bottom portion (22) can be separated and move around inside the battery pack (3), thereby minimizing the problem of difficulty in managing the battery pack (3).

[0097] According to one embodiment, the second vent portion (V2) may be a ring shape formed along the circumferential direction. This circular ring-shaped second vent portion (V2) may have the same center as the center of the bottom portion (22). The center of the second vent portion (V2) and the center of the second vent portion (V2) may be substantially the same. Additionally, the first electrode terminal (40) may be located radially inside the second vent portion (V2). The center of the second vent portion (V2) and the center of the first electrode terminal (40) may be substantially the same. Therefore, when a thermal event occurs, if the second vent portion (V2) breaks, the first electrode terminal (40) may also be discharged outside the battery cell (1).

[0098] However, the shape of the second vent portion (V2) is not limited by the embodiment and may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the bottom portion (22).

[0099] The diameter (d2) of the second vent section (V2) may be larger than the diameter (d1) of the first vent section (V1). Here, the diameter (d2) of the second vent section (V2) may refer to the diameter of the portion of the bottom section (22) of the can (20) surrounded by the second vent section (V2). Likewise, the diameter (d1) of the first vent section (V1) may refer to the diameter of the portion of the first current collector (30) surrounded by the first vent section (V1). In this case, when a thermal event occurs, the size of the second venting hole (23) formed by the broken second vent section (V2) may be larger than the size of the first venting hole (31) formed by the broken first vent section (V1).

[0100] According to an embodiment of the present invention, the diameter (d2) of the second vent portion (V2) is formed to be larger than the diameter (d1) of the first vent portion (V1), so that the broken portion of the first collector (30), which is separated by the first vent portion (V1), does not get caught on the bottom portion (22) of the can (20) and can be easily discharged through the second venting hole (23).

[0101] According to one embodiment, the first vent portion (V1) and the second vent portion (V2) may be located close together. In this way, when the first vent portion (V1) and the second vent portion (V2) are located close together, the first vent portion (V1) and the second vent portion (V2) may be broken at once when a thermal event occurs in the battery cell (1).

[0102] The diameter (d2) of the second vent section (V2) and the diameter (d1) of the first vent section (V1) can be designed to an appropriate size by considering whether the electrode assembly (10) can be easily discharged, whether connection with adjacent battery cells (1) and electrical connections such as busbars are easy.

[0103] FIG. 7 is an enlarged view of part A of FIG. 3 according to another embodiment of the present invention. FIG. 8 is a drawing showing a battery cell (1) according to another embodiment of the present invention viewed from an upward direction. FIG. 9 is a drawing showing the can (20), the first current collector (30), and the insulator (70) broken when a thermal event occurs in the battery cell (1) according to another embodiment of the present invention. When referring to FIG. 8, the first vent part (V1), the second vent part (V2), and the third vent part (V3) are not visible from the upper side of the battery cell (1), but for convenience of explanation, they are indicated and described.

[0104] The insulator (70) may be provided with a third vent section (V3). The third vent section (V3) may be configured to rupture due to the internal pressure of high-temperature venting gas when a thermal event occurs within the battery cell (1). That is, the third vent section (V3) may rupture when the pressure inside the can (20) exceeds a critical threshold. Accordingly, the venting gas formed within the battery cell (1) may be discharged from the battery cell (1) to the outside.

[0105] According to an embodiment of the present invention, when a thermal event occurs within the battery cell (1), the third vent portion (V3) formed in the insulator (70) ruptures, and the electrode assembly (10) and / or the first current collector (30) can pass through the insulator (70) and be discharged to the outside of the battery cell (1). That is, a vent portion is also formed in the insulator (70) so that the electrode assembly (10) and / or the first current collector (30) can be discharged more easily.

[0106] In other words, when a thermal event occurs within the battery cell (1), the third vent portion (V3) is broken, and a third venting hole (71) may be formed in the insulator (70). The third venting hole (71) may be surrounded by the third vent portion (V3). The third venting hole (71) may be formed radially inward of the third vent portion (V3). Accordingly, when a thermal event occurs within the battery cell (1), the electrode assembly (10) may pass through the third venting hole (71) and be discharged to the outside of the battery cell (1).

[0107] The third vent portion (V3) may be formed by notching along the circumferential direction. The thickness of the third vent portion (V3) may be formed thinner compared to other areas of the insulator (70). The third vent portion (V3) may be formed on one or both sides of the insulator (70). For example, the third vent portion (V3) may be formed on the upper and / or lower surfaces of the insulator (70). For example, the third vent portion (V3) may be implemented as a thin-walled portion with notched surfaces on both sides of the insulator (70).

[0108] According to an embodiment of the present invention, the third vent portion (V3) is formed thinner compared to the surrounding area, so it can be broken more easily than the surrounding area. That is, when the pressure inside the can (20) increases above a certain level, the third vent portion (V3) breaks, and the gas or electrode assembly (10) generated inside the can (20) can be discharged.

[0109] According to one embodiment, the third vent portion (V3) may have a closed-loop shape. A portion located radially inside the third vent portion (V3) in the insulator (70) and surrounded by the third vent portion (V3) may be separated from other parts of the insulator (70) and discharged to the outside of the battery cell (1) simultaneously with the breaking of the third vent portion (V3). However, the shape of the third vent portion (V3) is not limited by the above embodiment. According to another embodiment, although not shown in the drawings, the third vent portion (V3) may not form a closed loop so that the insulator (70) may not be separated even if the third vent portion (V3) breaks. Therefore, a portion of the insulator (70) may be separated and move around inside the battery pack (3), thereby minimizing the problem of difficulty in managing the battery pack (3).

[0110] According to one embodiment, the third vent portion (V3) may be a ring shape formed along the circumferential direction. This circular ring-shaped third vent portion (V3) may have the same center as the center of the insulator (70). However, the shape of the third vent portion (V3) is not limited by the embodiment and may form a continuous or discontinuous circular pattern, a straight pattern, or other pattern on the surface of the insulator (70).

[0111] The diameter (d3) of the third vent portion (V3) may be smaller than the diameter (d2) of the second vent portion (V2). Here, the diameter (d3) of the third vent portion (V3) may refer to the diameter of the portion of the insulator (70) surrounded by the third vent portion (V3). For example, referring to FIGS. 7 to 9, the diameter (d3) of the third vent portion (V3) may be larger than the diameter (d1) of the first vent portion (V1) and smaller than the diameter (d2) of the second vent portion (V2). In this case, when a thermal event occurs, the size of the second venting hole (23) formed by the broken second vent portion (V2) may be larger than the size of the third venting hole (71) formed by the broken third vent portion (V3).

[0112] According to an embodiment of the present invention, the diameter (d3) of the third vent portion (V3) is formed to be smaller than the diameter (d2) of the second vent portion (V2), so that the broken portion of the insulator (70) separated by the third vent portion (V3) does not get caught on the bottom portion (22) of the can (20) and can be easily discharged through the second venting hole (23).

[0113] In addition, according to the embodiment of the present invention, since more insulator (70) remains than the bottom portion (22) of the can (20) after the first vent portion (V1), the second vent portion (V2), and the third vent portion (V3) are broken, electrical insulation between the can (20) and the first current collector (30) can be maintained by the insulator (70) even after the third vent portion (V3) is broken.

[0114] In addition, according to an embodiment of the present invention, the diameter (d3) of the third vent portion (V3) is formed to be larger than the diameter (d1) of the first vent portion (V1), so that the broken portion of the first current collector (30), which is separated when the first vent portion (V1) is broken, does not get caught on the insulator (70) and can be easily discharged through the third venting hole (71).

[0115] However, the diameter (d3) of the third vent (V3) may be the same as or smaller than the diameter (d1) of the first vent (V1), and the design may be changed in various ways.

[0116] FIG. 10 is a plan view of a first current collector (30) according to another embodiment of the present invention.

[0117] The first current collector (30) may include a non-removable part coupling part (32), a terminal coupling part (33), and a bridge part (34).

[0118] The non-bonded portion connecting part (32) may be configured to be electrically connected to the electrode assembly (10). The non-bonded portion connecting part (32) may be a part that is connected to the non-bonded portion of the first electrode. That is, the non-bonded portion connecting part (32) may be connected to the first non-bonded portion (11). The non-bonded portion connecting part (32) may be connected on a connecting surface formed by bending the first non-bonded portion (11). At least a portion of the non-bonded portion connecting part (32) may be welded to the first non-bonded portion (11) in an area where the number of overlapping layers of segments of the first non-bonded portion (11) is maximized. At this time, the portion of the non-bonded portion connecting part (32) that can actually be welded to the first non-bonded portion (11) may be defined as a welded portion (321).

[0119] The terminal coupling portion (33) may be a part that is coupled to the first electrode terminal (40). The terminal coupling portion (33) may be welded to the first electrode terminal (40) by a welding tool inserted through the winding center hole of the electrode assembly (10) or by a laser irradiated through the winding center hole.

[0120] The bridge portion (34) may be configured to electrically connect the non-removable portion coupling portion (32) and the terminal coupling portion (33). Multiple non-removable portion coupling portions (32) may be provided along the circumferential direction of the first current collector (30). In this case, multiple bridge portions (34) may also be provided.

[0121] The non-bonding portion (32) and the terminal portion (33) may be positioned spaced apart from each other along the radial direction of the electrode assembly (10). That is, a void space may be formed between the non-bonding portion (32) and the terminal portion (33) along the radial direction. In particular, the first current collector (30) may be provided with a slit line (35). The slit line (35) may be formed by penetrating the first current collector (30). That is, the slit line (35) may be formed by penetrating the first current collector (30), which has a roughly flat shape and is in the shape of a roughly circular plate. The non-bonding portion (32), the terminal portion (33), and the bridge portion (34) of the first current collector (30) may be formed by this slit line (35). The non-bonding portion (32) and the bridge portion (34) may be spaced apart from each other along the circumferential direction by the slit line (35). The non-removable joint (32) and the terminal joint (33) may be separated along the radial direction by a slit line (35). The non-removable joint (32) and the terminal joint (33) may not be directly connected but may be indirectly connected through a bridge (34), thereby dispersing and / or absorbing the impact transmitted to the welded joint (32) and / or the terminal joint (33) when an impact is applied to the first current collector (30).

[0122] In this way, when a structure is applied in which each component of the first current collector (30) is distinguished by a slit line (35), a complex process is not required to form each component, namely the non-removable part connection part (32), the terminal connection part (33), and the bridge part (34), and the first current collector (30) can be manufactured relatively easily by simply forming a cut line on a metal plate.

[0123] The first vent portion (V1) may be formed in the non-reinforced portion joining portion (32) and the bridge portion (34). At this time, the weld portion (321), configured to be welded to the actual first non-reinforced portion (11) at the non-reinforced portion joining portion (32), may be positioned so as to be spaced apart from the first vent portion (V1). The weld portion (321) may not overlap with the first vent portion (V1). That is, the weld portion (321) may not be formed across the first vent portion (V1). Accordingly, the weld portion (321) may be formed on the inner and / or outer side of the first vent portion (V1).

[0124] According to an embodiment of the present invention, the first vent portion (V1) is spaced apart from the weld portion (321), so that the first vent portion (V1) does not affect the welding of the first non-welded portion (11) and the first current collector (30). That is, since the first vent portion (V1) is not welded, the bonding strength may not be strengthened, and it may easily break in a high temperature / high pressure environment.

[0125] FIG. 11 is a drawing for explaining a battery pack (3) according to an embodiment of the present invention. FIG. 12 is a drawing for explaining a vehicle including the battery pack (3) of FIG. 11.

[0126] Referring to FIG. 11, 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.

[0127] 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.

[0128] 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 each battery cell (1) may be arranged such that a first electrode terminal (40) having a first polarity and a second electrode terminal (25) having a second polarity are both positioned on the upper side. Therefore, 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.

[0129] 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. 12, the vehicle's mileage relative to energy can be further increased.

[0130] Referring to FIG. 12, the automobile (V) according to the present invention may include at least one battery pack (3) according to the present invention.

[0131] 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.

[0132] 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

An electrode assembly comprising a first electrode and a second electrode and a separator interposed between them, wound along a winding axis; A can comprising a side wall portion, a bottom portion connected to one end of the side wall portion in the direction of the winding axis, and an open end formed at the other end of the side wall portion in the direction of the winding axis, configured to accommodate the electrode assembly through the open end; A first current collector having a first vent portion configured to be electrically connected to the first electrode and configured to break when a thermal event occurs within the battery cell; and A battery cell comprising: a first electrode terminal configured to cover a through hole formed in the bottom portion and to be electrically connected to the first current collector. In Article 1, A battery cell characterized in that, in the first current collector, when a thermal event occurs within the battery cell, the first vent portion is broken to form a first venting hole surrounded by the first vent portion. In Article 1, A battery cell characterized in that the first vent portion is formed by notching. In Article 1, A battery cell characterized in that the first vent portion is a ring shape formed along the circumferential direction. In Article 1, A battery cell characterized by having a second vent portion configured to break when a thermal event occurs within the battery cell, wherein the bottom portion is configured to break. In Article 5, A battery cell characterized in that the first electrode terminal is located on the radially inner side of the second vent portion. In Article 5, A battery cell characterized in that the diameter of the second vent portion is larger than the diameter of the first vent portion. In Article 5, A battery cell characterized by being configured such that, when a thermal event occurs within the battery cell, the second vent portion is ruptured, thereby forming a second venting hole surrounded by the second vent portion. In Article 5, A battery cell further comprising: an insulator having a third vent portion positioned between the can and the first current collector and configured to break upon the occurrence of a thermal event within the battery cell. In Paragraph 9, A battery cell characterized in that the diameter of the third vent portion is smaller than the diameter of the second vent portion. In Article 1, A battery cell characterized in that the first current collector further comprises a non-bonding portion coupling portion which is a portion coupled to the non-bonding portion of the first electrode, and a terminal coupling portion which is a portion coupled to the first electrode terminal, and a weld portion configured to be welded to the non-bonding portion at the non-bonding portion coupling portion is arranged to be spaced apart from the first vent portion. A battery pack characterized by comprising at least one battery cell described in any one of claims 1 to 11. An automobile characterized by comprising at least one battery cell described in any one of claims 1 to 11.

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