Battery cell, battery pack comprising the battery cell, and vehicle

Abstract

A battery cell according to the present application includes: an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound around a winding axis; a battery can including a side wall portion formed in a hollow shape and a bottom portion connected to one axial end portion of the side wall portion, and accommodating the electrode assembly through the other axial end portion of the side wall portion; and a cap for covering the other end portion of the battery can, wherein the side wall portion includes a first side wall axially extending from an edge of the bottom portion and a second side wall extending from the first side wall and having an inner diameter smaller than that of the first side wall, and wherein the cap can be coupled to an inner side surface of the second side wall.

Description

Technical Field

[0001] This disclosure relates to a battery cell, a battery pack including the battery cell, and a vehicle. This disclosure also relates to a method for manufacturing the battery cell. This application claims priority to Korean Patent Application No. 10-2024-0101000, filed with the Korean Intellectual Property Office on July 30, 2024, the entire disclosure of which is incorporated herein by reference. Background Technology

[0002] Cylindrical battery cells have a structure in which coiled electrode assemblies are housed within a cylindrical metal battery can, and exhibit greater resistance to shock and temperature compared to pouch cells. Therefore, the demand for metal-can type cells used in vehicle battery packs is increasing.

[0003] A method for manufacturing battery cells using a cylindrical battery can may include the following steps: manufacturing a battery can having a circular bottom and cylindrical sidewalls, the cylindrical sidewalls being connected to the bottom by deep-drawn metal sheets; housing an electrode assembly within the battery can; and sealing the opening of the battery can with a cap. The sealing method may include crimping, pressing, or welding the interface between the battery can and the cap. The welding method may be seam welding or butt welding.

[0004] Increasing battery capacity and reducing costs are key technological challenges, thus seam welding is attracting attention. Regarding seam welding, preventing damage to the electrode assemblies housed within the casing during the welding process is likely a critical technological challenge.

[0005] Figure 1 The traditional process of welding the side wall and cap of the battery can is shown.

[0006] Compared to edge crimping and pressing, welding the sidewall 1002 and cap 1001 of the battery can improves the utilization of the internal space of the battery can, thereby increasing energy density. However, when gaps exist due to tolerances between the sidewall 1002 and cap 1001 of the battery can, the welding laser beam L can enter the internal space of the battery can, damaging the electrode assembly. Furthermore, even if the welding is successful, the weld thickness is reduced, resulting in insufficient weld strength. Additionally, performing precision machining to reduce the tolerances between the cap and the battery can increases the unit cost for manufacturing the battery cell.

[0007] Even if there are tolerances between the sidewalls and caps of the pre-formed battery can, if a method is provided during the battery cell manufacturing process to reduce the gap between the sidewalls and caps of the battery can, or if the battery cell has such a structure, the electrode assembly can be protected and productivity can be improved. Summary of the Invention

[0008] Technical issues

[0009] This disclosure is designed to solve problems in related technologies, and therefore aims to provide a battery cell and a method for manufacturing the same, which can reduce the gap caused by tolerances when joining the side wall portion of the battery can to the cap.

[0010] This disclosure also relates to a battery cell and a method for manufacturing the same, which enables the battery can and cap to fit tightly together without deforming the contact surface during the insertion of the cap into the open end of the battery can.

[0011] This disclosure also aims to provide a battery pack and a vehicle that include such battery cells.

[0012] The technical challenges of this disclosure are not limited to those mentioned above, and other objects and advantages of this disclosure not mentioned above will be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0013] Technical solution

[0014] In one aspect of this disclosure, a battery cell is provided, the battery cell comprising: an electrode assembly formed by winding a first electrode, a second electrode, and a separator inserted between the first electrode and the second electrode around a winding shaft; a battery can having a sidewall portion and a bottom, the sidewall portion being formed in a hollow shape, the bottom being connected to an axial end of the sidewall portion, and the battery can receiving the electrode assembly through another axial end of the sidewall portion; and a cap covering the other axial end of the battery can, wherein the sidewall portion may include a first sidewall extending axially from an edge of the bottom and a second sidewall extending from the first sidewall and having an inner diameter smaller than the inner diameter of the first sidewall, and wherein the cap may be coupled to an inner surface of the second sidewall.

[0015] According to this disclosure, the second sidewall can be formed to be inclined inward from the first sidewall.

[0016] Additionally, the second sidewall may include a first portion that is formed to slope inward from the first sidewall and a second portion that is formed to extend axially from the first portion.

[0017] Additionally, the cap can be configured such that the portion attached to the second sidewall is elastically biased in the direction in which it fits tightly against the second sidewall.

[0018] Additionally, the cap may include a body, an abutment portion, and an elastically deformable portion. The body covers the upper side of the electrode assembly, the abutment portion fits tightly against the second sidewall, and the elastically deformable portion connects the body and the abutment portion, and provides an elastic force that allows the abutment portion to fit tightly against the second sidewall.

[0019] Additionally, the elastic deformation portion may include a curved portion and an inclined portion, the curved portion extending from the abutment portion and having a curved structure that changes the direction of extension, and the inclined portion extending from the end of the curved portion and overlapping the abutment portion at least partially with respect to the axial direction.

[0020] In addition, the curved portion may have a notch, and when an external force is applied, the curved portion may deform with reference to the notch.

[0021] Additionally, the cap may include an exhaust portion for venting air, the exhaust portion being located in the inner region of the curved portion.

[0022] Additionally, the cap can be attached to one side surface of the electrode assembly for electrical connection to the electrode assembly.

[0023] In another aspect of this disclosure, a battery pack including battery cells according to embodiments of this disclosure is provided.

[0024] In another aspect of this disclosure, a vehicle is provided that includes a battery pack according to an embodiment of this disclosure.

[0025] A method for manufacturing a battery cell according to embodiments of the present disclosure may include the following steps: a battery can preparation step for preparing a battery can having a sidewall portion and a bottom, the sidewall portion being formed in a hollow shape and the bottom being connected to one axial end of the sidewall portion; an electrode assembly receiving step for inserting an electrode assembly into the battery can through the other axial end of the sidewall portion; a cap assembly step for inserting a cap into the other axial end of the sidewall portion; a processing step for plastically deforming a portion of the sidewall portion inward to reduce the inner diameter of the sidewall portion; and a cap joining step for joining the reduced inner diameter portion of the sidewall portion to the edge of the cap.

[0026] According to this disclosure, in the processing step, the other axial end of the sidewall portion can be processed to be inclined inward.

[0027] Additionally, the cap may include a body having an upper side covering the electrode assembly and an abutment portion connected to the body and formed axially to face the sidewall portion. In the processing step, as the inner diameter of the sidewall portion decreases, the sidewall portion and the abutment portion can fit tightly together. In the cap joining step, the abutment portion and the sidewall portion can be joined in a tightly fitted state.

[0028] Additionally, the cap may include an elastically deformable portion configured to connect the body and the abutment portion, and provide an elastic force that causes the abutment portion to fit tightly against the sidewall portion.

[0029] Beneficial effects

[0030] According to one aspect of this disclosure, since the sidewall portion of the battery can is extruded inward in the radial direction, even if there is a gap caused by tolerance between the edge of the cap and the sidewall portion of the battery can, the battery can and the cap can be made to fit tightly together later.

[0031] In particular, the sidewall of the battery can be press-formed to be inclined at a predetermined angle or have a constant inner diameter, so that the edge of the cap can also be deformed accordingly, thereby allowing the battery can to fit tightly against the cap.

[0032] Therefore, the battery can and cap can be joined when the edge of the cap fits tightly against the battery can. For example, during laser welding, the laser beam does not enter the internal space of the battery can, thus preventing damage to the electrode assembly. Additionally, sufficient weld thickness can be achieved to provide high weld strength.

[0033] Furthermore, since precision machining is not required to reduce the tolerance between the sidewall of the battery can and the cap, productivity can be increased without increasing the manufacturing cost of the battery cells, while protecting the electrode assembly.

[0034] However, the effects that can be obtained from this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the following description of the invention that are not mentioned above. Attached Figure Description

[0035] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure is not to be construed as limited to the drawings.

[0036] Figure 1 This diagram illustrates a conventional process for sealing a battery can by welding the sidewalls and the cap.

[0037] Figure 2 This is a perspective view of a battery cell according to an embodiment of the present disclosure.

[0038] Figure 3 yes Figure 2 The diagram shows a schematic cross-sectional view of the battery cell.

[0039] Figure 4 yes Figure 2 A schematic perspective view of the hat shown.

[0040] Figure 5 It is viewed from below. Figure 4 The hat shown is a perspective view.

[0041] Figure 6 yes Figure 4 The diagram shows a schematic cross-sectional view of the cap.

[0042] Figure 7 yes Figure 3 An enlarged view of part A in the image.

[0043] Figure 8 This is a diagram illustrating the process used to form the second sidewall.

[0044] Figure 9 This is a diagram showing the second sidewall of a battery cell according to another embodiment of the present disclosure.

[0045] Figure 10 This is a partial cross-sectional view of a battery cell according to another embodiment of the present disclosure.

[0046] Figure 11 This is a partial cross-sectional view of a battery cell according to another embodiment of the present disclosure.

[0047] Figure 12 This is a diagram illustrating a battery pack according to an embodiment of the present disclosure.

[0048] Figure 13 It shows including Figure 12 A diagram of a vehicle with a battery pack. Detailed Implementation

[0049] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0050] This disclosure is not limited to the embodiments disclosed below, but can be implemented with various modifications and configurations. These embodiments are provided merely to complete the disclosure and to fully convey the scope of the invention to those skilled in the art. Therefore, this disclosure is not limited to the embodiments set forth herein, and it should be understood that the configuration of one embodiment can be replaced or combined with the configuration of another embodiment, thereby encompassing all modifications, equivalents, and substitutions falling within the concept and scope of this disclosure.

[0051] Furthermore, this disclosure may include various embodiments. Additionally, in each embodiment, repeated descriptions of substantially the same or similar structures are omitted, and descriptions are based on their differences.

[0052] The accompanying drawings are provided merely to facilitate understanding of the embodiments disclosed herein, and the technical concepts disclosed herein should not be construed as being limited to the drawings. It should be understood that all modifications, equivalents, and substitutions falling within the concepts and scope of this disclosure are permitted. In the drawings, the dimensions or thickness of elements may be exaggerated or reduced for clarity and ease of understanding, but this should not be construed as limiting the scope of this disclosure.

[0053] The terminology used herein is intended only to describe particular embodiments and implementations and is not intended to limit the scope of this disclosure. Furthermore, unless the context clearly indicates otherwise, the singular forms used herein are intended to include the plural forms as well. Terms such as “comprising” or “including” as used herein are intended to specify the presence of the features, integrals, steps, operations, elements, components, or combinations thereof described herein. That is, terms such as “comprising” or “including” as used herein should be understood to not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, or combinations thereof.

[0054] Throughout this instruction manual, unless otherwise expressly stated, each component may be singular or plural.

[0055] At the same time, although terms such as up, down, left, right, front, and back are used in this specification to indicate directions, it will be apparent to those skilled in the art to which this disclosure pertains that these terms are merely for the purpose of interpretation with reference to the accompanying drawings and may vary depending on the position, arrangement, or rotation of the target object or the position of the observer.

[0056] For ease of explanation, the winding axis direction indicates the direction in which the axis of the winding center of the core-shaped electrode assembly extends, the radial direction indicates the direction close to the winding axis (centripetal direction) or away from the winding axis (centrifugal direction), and the circumferential direction indicates the direction around the winding axis.

[0057] Figure 2 This is a perspective view of a battery cell according to an embodiment of the present disclosure. Figure 3 yes Figure 2 The diagram shows a schematic cross-sectional view of the battery cell.

[0058] Reference Figure 2 and Figure 3 According to this embodiment, the battery cell 10 may include an electrode assembly 100, a battery canister 200, and a cap 300.

[0059] The electrode assembly 100 can be configured as a core, wherein a first electrode, a second electrode, and a diaphragm inserted therebetween are wound around a winding axis. Specifically, the electrode assembly 100 can be manufactured into a cylindrical core shape by preparing a first electrode, a second electrode, and a diaphragm extending along the length direction with a predetermined width, sequentially stacking the first electrode, the diaphragm, the second electrode, and the diaphragm to form a laminate, and then winding the laminate around a winding axis. The structure of the electrode assembly 100 is not limited to this embodiment and can have various winding structures known in the art.

[0060] The battery canister 200 may include a sidewall portion 210 and a bottom portion 220. The sidewall portion 210 may be formed as a hollow cylinder. The bottom portion 220 may be disposed in the axial direction of the sidewall portion 210 (i.e., Figure 3 At one end of the vertical direction (Z-axis direction) in the middle. For example, as... Figure 3 As shown, the bottom 220 can be disposed at the lower end of the side wall portion 210. The bottom 220 can be formed in a disc shape and connected to the lower end of the side wall portion 210 to close the lower end of the side wall portion 210. The other end (i.e., the upper end) of the battery can 200 can be configured to be open. Furthermore, the electrode assembly 100 can be accommodated within the battery can 200 through the open end (i.e., the upper end) of the battery can 200.

[0061] Specifically, the sidewall portion 210 may include a first sidewall 211 and a second sidewall 212. The first sidewall 211 may extend from the edge of the bottom 220 in the axial direction (i.e., upward direction). As a result, the inner diameter of the first sidewall 211 may be substantially the same as the diameter of the bottom 220. The second sidewall 212 may extend from the first sidewall 211, but may be formed to have a smaller inner diameter than the first sidewall 211. Specifically, the second sidewall 212 may be formed at the upper end of the entire sidewall portion 210, i.e., the open end. The second sidewall 212 may be formed to have a smaller inner diameter than the first sidewall 211. For example, the upper end of the sidewall portion 210 may be plastically deformed inward by roll forming (or roll forming), thereby reducing the inner diameter of the plastically deformed portion. Here, the plastically deformed portion of the sidewall portion 210 may constitute the second sidewall 212, while the non-plastically deformed portion (i.e., the lower part of the second sidewall 212) may constitute the first sidewall 211. In this configuration, the second sidewall 212 can be formed with the cap 300 inserted into the sidewall portion 210, allowing the second sidewall 212 to fit tightly against the cap 300. This plastic deformation process will be described later.

[0062] A cap 300 can be attached to the battery can 200 to cover the open end, i.e., the upper end. Specifically, the cap 300 can be formed in a shape corresponding to the upper end of the battery can 200. For example, the cap 300 can be formed in the shape of a circular plate. The cap 300 can be inserted into the interior of the battery can 200 and attached to the battery can 200. For example, the edge of the cap 300 can be welded to the inner circumferential surface of the battery can 200. As a result, the cap 300 can cover or close the upper end of the battery can 200.

[0063] Specifically, in this embodiment, the edge of the cap 300 can be attached to the inner surface of the second sidewall 212 of the battery canister. For example, the edge of the cap 300 can be welded to the second sidewall 212.

[0064] According to the above construction, the edge of the cap 300 can be welded to the second sidewall 212 of the battery can 200. In this case, since the second sidewall 212 protrudes inward and has a reduced inner diameter, the edge of the battery can 300 can fit tightly against the second sidewall 212. Specifically, since the second sidewall 212 is formed by pressing the sidewall portion 210 of the battery can in the radial direction, even if there is a gap due to the tolerance between the edge of the cap 300 and the sidewall portion 210 of the battery can, the second sidewall 212 and the edge of the cap 300 may fit tightly against each other later.

[0065] Therefore, the cap 300 and the battery canister 200 can be joined with the edge of the cap 300 in close contact with the battery canister 200. For example, when laser welding is performed, the laser beam is prevented from entering the internal space of the battery canister 200, thereby preventing damage to the electrode assembly 100 due to the laser beam. In addition, sufficient weld thickness can be ensured to provide high weld strength.

[0066] In addition, since precision machining is not required to reduce the tolerance between the side wall portion 210 of the battery can and the cap 300, productivity can be increased without increasing the manufacturing cost of the battery cell, while protecting the electrode assembly.

[0067] Specifically, according to this embodiment, the second sidewall 212 may be formed to be inclined inward from the first sidewall 211. Specifically, the second sidewall 212 may be provided at the upper end of the sidewall portion 210. For example, the second sidewall 212 may be formed to extend from the first sidewall 211 and be inclined, such that its inner diameter decreases in the extending direction.

[0068] According to this embodiment, the second sidewall 212 can be formed to be inclined inward, thereby allowing the second sidewall 212 to fit tightly against the edge of the cap 300. Therefore, the sidewall portion 210 of the battery can and the cap 300 can be stably and firmly welded.

[0069] Specifically, according to this embodiment, the surfaces where the second sidewall 212 and the cap 300 intersect can be formed as inclined. As a result, when welding the second sidewall 212 and the cap 300, the laser beam can be guided in an inclined direction, i.e., in a direction parallel to the second sidewall, rather than in a vertical direction. Therefore, even if a portion of the laser beam passes through the contact surface between the battery canister 200 and the cap 300 during welding, it can only reach the inner wall of the battery canister, more specifically, the boundary between the first sidewall 211 and the second sidewall 212, rather than the electrode assembly 100. Therefore, damage to the electrode assembly during welding can be prevented.

[0070] The specific structure of the battery can and cap will be described in more detail below. Figure 4 yes Figure 2 A schematic perspective view of the hat shown. Figure 5 It is viewed from below. Figure 4 The hat shown is a perspective view. Figure 6 yes Figure 4 A schematic cross-sectional view of the cap shown. Figure 7 yes Figure 3 An enlarged view of part A in the image. Figure 8 This is a diagram illustrating the process used to form the second sidewall. For reference, Figures 4 to 6 The structure of the cap before it deforms together with the second sidewall is shown during the formation of the second sidewall. Additionally, Figure 7 It is a diagram showing the state in which the edge of the cap is welded while deforming inward along the side wall of the battery can (more specifically, along the second side wall).

[0071] Reference Figures 4 to 8 According to this embodiment, the cap 300 can be configured such that the portion to be connected to the second sidewall 212 is elastically biased in the direction that causes it to fit tightly against the second sidewall 212. Specifically, as Figure 8 As shown, when the second sidewall 212 is formed inward, the edge of the cap 300 can deform inward together with the second sidewall 212. In this case, the cap 300 is made of metal and has a certain degree of elasticity. Therefore, once the edge of the cap 300 is deformed inward, it tends to return to its original state in the outward direction. That is, the edge of the cap 300 can be elastically biased in the outward direction (i.e., in the direction that makes it fit tightly against the second sidewall 212).

[0072] In this case, the elastic force applied to the edge of the cap 300 can be further enhanced depending on the structure of the edge of the cap 300 and the parts attached thereto, which will be described in more detail below.

[0073] According to this embodiment, the cap 300 may include a main body 310, an abutment portion 320, and an elastically deformable portion 330. The main body 310 corresponds to the central portion of the cap 300 and may be arranged above the electrode assembly 100 to cover the upper space of the electrode assembly 100. The abutment portion 320 may be connected to the main body 310 via the elastically deformable portion 330. The abutment portion 320 may be disposed on the outer edge of the cap 300 in the radial direction (X-axis direction). The abutment portion 320 may have an integral toroidal shape and may be formed to have a predetermined width in the axial direction (i.e., the vertical direction (Z-axis direction)). The abutment portion 320 may fit tightly against the second sidewall 212 and may be joined (e.g., welded) to the second sidewall 212 while fitting tightly against the second sidewall 212. The elastically deformable portion 330 may be arranged between the main body 310 and the abutment portion 320 and may connect the main body 310 and the abutment portion 320. The elastic deformation portion 330 can provide elasticity to ensure that the abutment portion 320 fits tightly against the second sidewall 212. When the abutment portion 320 deforms inward together with the second sidewall 212, the elastic deformation portion 330 can deform together with the abutment portion 320. In this case, the elastic deformation portion 330 can be configured to deform within the elastic deformation range rather than plastic deformation, and can be formed into a structure that facilitates deformation.

[0074] Specifically, the elastically deformable portion 330 may include a curved portion 331 and an inclined portion 332. The curved portion 331 extends from the abutment portion 320 in a curved shape. Therefore, the curved portion 331 may extend such that its direction of extension changes. For example, as Figure 6 As shown, the curved portion 331 can extend downward from the abutment portion 320, and gradually becomes less steep as it extends away from the abutment portion 320. That is, since the abutment portion 320 extends parallel to the axial direction (vertical direction), the slope of the tangent on the outer surface of the curved portion 331 can gradually decrease from 90 degrees as the curved portion 331 extends away from the abutment portion 320, and thereafter, the extension direction of the curved portion 331 can be changed to extend upward.

[0075] The inclined portion 332 can extend from the curved portion 331. The inclined portion 332 can be formed to be inclined upward in the axial direction and inward in the radial direction. At least a portion of the inclined portion 332 can overlap with the abutting portion 320 in the axial direction (i.e., the vertical direction). That is, when the curved portion 331 extends, its extension direction gradually changes from downward to upward, and the inclined portion 332 extends directly from the end of the curved portion 331, so the abutting portion 320 and the inclined portion 332 can overlap. That is, the abutting portion 320 and the inclined portion 332 can overlap in the Z-axis direction.

[0076] Using this structure, the abutment portion 320, the curved portion 331, and the inclined portion 332 can be bent to form an overall U-shaped bend.

[0077] According to the above implementation method, such as Figure 8 As shown, when the second sidewall 212 is pressed by the roller R and formed to be inclined inward, the abutment portion 320 can deform together with the second sidewall 212 while being in close contact with it. At this time, the elastic deformation portion 330 can deform together with the abutment portion 320, so that it can be deformed into an inclination. For example, the curved portion 331 can be bent to have a small radius of curvature, thereby causing the abutment portion 320 to be inclined.

[0078] In this case, the curved portion 331 deforms to have a small radius of curvature, and then tends to straighten due to the restoring force. Therefore, the abutment portion 320 connected to the curved portion 331 can be elastically biased to fit tightly against the second sidewall 212.

[0079] Furthermore, the cap 300 with the U-shaped curve is adapted to be inserted (press-fit) into the open end of the battery can 200. Specifically, the curve 331 and the inclined portion 332 provide a structure that allows the cap 300 to elastically deform radially inward. Therefore, when the cap 300 is press-fitted into the open end, the U-shaped curve can be compressed and then opened, allowing the cap 300 to fit into the sidewall portion 210 while minimizing deformation of other parts. As a result, the contact force between the sidewall portion 210 of the battery can and the abutment portion 320 can be fixed. That is, when the cap 300 is press-fitted into the battery can 200, they can fit tightly without deforming the abutment portion 320.

[0080] Furthermore, in this disclosure, even if there is a gap between the abutment portion 320 and the side wall portion 210 due to tolerances or shape differences, the gap between the second side wall 212 and the abutment portion 320 can be eliminated during the pressing process.

[0081] See back Figures 4 to 7 The cap according to this embodiment will be described further.

[0082] The main body 310 of the cap may include a support surface 311, an electrode connection portion 312, an exhaust portion 313, and an electrolyte injection hole 314.

[0083] The support surface 311 can be disposed inside the elastically deformable portion 330. Specifically, the support surface 311 can extend horizontally inward from the end of the inclined portion 332. That is, the support surface 311 can be connected to the radially inner end of the inclined portion 332 and can extend horizontally inward from the connection point in the radial direction. The support surface 311 can provide a flat surface between the inclined portion 332 and the electrode connection portion 312. In other words, the support surface 311 can have a flat annular shape, and when the battery cell 10 is erected with the cap 300 arranged on the bottom, the support surface 311 can be used to support the battery cell 10.

[0084] The electrode connection portion 312 may be a portion electrically connected to the electrode assembly 100. The electrode connection portion 312 may be located further inward than the support surface 311. The electrode connection portion 312 may extend from the main body 310 towards the interior of the battery canister 200 (i.e., in...). Figure 7 The portion is recessed in the downward direction (-Z axis direction). The electrode connection portion 312 can be formed by plastically deforming a portion of the cap 300 in the form of a metal plate, thereby making it recessed downward.

[0085] Reference Figure 7 When the cap 300 is inserted into the battery canister 200, the cap 300 can be inserted to a position where the bottom surface of the electrode connection portion 312 conforms to the upper surface (i.e., the second uncoated portion 102) of the electrode assembly 100 housed within the battery canister 200. The electrode connection portion 312 and the second uncoated portion 102 can be joined by welding. Welding can be performed by irradiating the outer surface of the electrode connection portion 312a with a laser. The laser beam can be guided in the radial direction to form a radially extending weld portion.

[0086] As a result, the cap 300 serves as a cap to seal the open end of the battery can 200, and also as a current collector for the second electrode (e.g., the negative electrode).

[0087] The joint between the electrode connection portion 312 and the second uncoated portion 102 can extend radially. Multiple electrode connections 312 can be provided and arranged radially around the center of the cap 300. A pair of electrode connections 312 facing each other with reference to the center of the cap 300 can be aligned in a straight line.

[0088] Therefore, multiple electrode connections 312 can be arranged radially at equal intervals along the circumferential direction. The electrode connections 312 can extend radially and thus can connect to the second uncoated portion 102 disposed from the outer periphery of the electrode assembly 100 to the core. This weld line widens the current path, thereby significantly reducing the internal resistance of the second electrode.

[0089] When the cap 300 described above is applied, the connection between the cap 300 and the battery canister 200 is simplified, and a current collector is not required to electrically connect the second uncoated portion 102 to the battery canister 200. Therefore, the number of parts and assembly time can be reduced, and the internal volume can be increased, thereby improving energy density.

[0090] The vent 313 can be provided for smooth venting during thermal events of the battery cell 10. The vent 313 can be disposed inside the curved portion 331. For example, as... Figure 6As shown, the vent 313 can be provided on the support surface 311. The vent 313 can be made into a thin-walled portion by slotting on both sides of the support surface 311. The vent 313 can be configured to resist deformation under applied force when the cap 300 is press-fitted into the battery canister 200, but to rupture when the internal pressure of the battery canister 200 suddenly increases. When the vent 313 ruptures, the electrode connection portion 312 of the cap 300 and the abutment portion 320 of the cap 300 can be separated. Therefore, the electrical connection between the electrode connection portion 312 connected to the second uncoated portion 102 and the battery canister 200 can be cut off, and the gas inside the battery canister 200 can be discharged to the outside.

[0091] The electrolyte injection port 314 can be located at the center of the cap 300. When the open end of the battery can 200 is covered by the cap 300, the electrolyte injection port 314 can be aligned with the winding center hole of the electrode assembly 100 housed in the battery can 200.

[0092] The electrolyte injection port 314 can be located on the bottom surface of the cap 300, slightly above the electrode connection portion 312 of the cap 300. The electrolyte injection port 314 can be closed by a cap 315. The cap 315 can be a ball, a plug, or other structure. The edge of the cap 315 can be sealed with the edge of the electrolyte injection port 314. This seal can be achieved by seam welding or other known sealing methods.

[0093] Figure 9 This is a diagram showing the second sidewall of a battery cell according to another embodiment of the present disclosure.

[0094] Reference Figure 9 According to this embodiment, the sidewall portion 210 of the battery can may include a first sidewall 211 and a second sidewall 212. The first sidewall 211 may extend axially (i.e. upward) from the bottom edge. The second sidewall 212 may extend from the first sidewall 211 and has an inner diameter smaller than that of the first sidewall 211.

[0095] Specifically, a second sidewall 212 may be formed at the upper end of the sidewall portion 210, i.e., the open end. The second sidewall 212 may be configured to include a first portion 212a and a second portion 212b. The first portion 212a may be formed to slope inward from the first sidewall 211. For example, the first portion 212a may extend from the first sidewall 211 in an inclined manner, such that its inner diameter decreases as it extends. The second portion 212b may extend upward from the end (upper end) of the first portion 212a. That is, the second sidewall 212 may be configured such that its inner diameter in the cross-section of the first portion 212a becomes smaller than the inner diameter of the first sidewall 211, and the second portion 212b extends upward in a decreasing inner radial direction.

[0096] The structure of the second sidewall 212 can be formed by plastically deforming the upper end of the sidewall portion 210 inward through roll forming (or roll forming). For example, as Figure 9 As shown in (a), when the upper end of the sidewall is pressed inward by the roller R, the first portion 212a can be plastically deformed inward to become inclined. In this case, the second sidewall 212 can be formed with the cap 300 inserted into the sidewall portion 210, and therefore the second sidewall 212 can fit tightly against the cap 300.

[0097] Figure 10 This is a partial cross-sectional view of a battery cell according to another embodiment of the present disclosure.

[0098] Reference Figure 10 The cap 300 according to this embodiment may also have a notch 331a. The notch 331a can be formed in the elastically deformable portion 330 to allow the elastically deformable portion 330 to deform more smoothly. For example, the notch 331a can be formed in the curved portion 331 of the elastically deformable portion. In particular, the notch 331a can be formed at the portion where the extension direction of the curved portion 331 changes, i.e., at the portion where the tangent slope is close to zero. That is, the notch 331a can be formed at the center of the U-shaped bend. The notch 331a can be implemented by forming a "V"-shaped groove in the curved portion 331.

[0099] According to this embodiment, when the abutment portion 320 is pressed inward, the curved portion 331 of the elastic deformation portion can deform with reference to the notch 331a. Specifically, as Figure 10 As shown in (b), when the abutment portion 320 deforms inward, the curved portion 331 can bend in a manner that reduces its inner diameter. In this case, if a notch 331a is formed in the curved portion 331, the curved portion 331 can be deformed to bend around the notch 331a, thereby facilitating the deformation of the curved portion 331.

[0100] In response, in such Figure 8 and Figure 9 During the formation of the inwardly pressing sidewall portion 210, the external force transmitted to the cap 300 through the sidewall portion 210 can be significantly reduced due to the deformation of the elastic deformation portion 330. However, some external force can still be transmitted further inward, even to the exhaust portion 313. That is, not only the abutting portion 320 and the elastic deformation portion 330 deform under the action of external force, but the exhaust portion 313 can also deform. However, since the exhaust portion 313 is configured to have low strength, it can be deformed or broken very easily. Therefore, there is a risk of damage to the exhaust portion 313 during the formation of the sidewall portion 210.

[0101] However, if the notch 331a is provided in the elastic deformation portion disclosed in this embodiment, the elastic deformation portion 330 can bend around the notch 331a, thereby preventing or reducing the transmission of external force to the exhaust portion 313. Therefore, damage to the exhaust portion 313 can be prevented during the formation of the sidewall portion 210.

[0102] Figure 11 This is a partial cross-sectional view of a battery cell according to another embodiment of the present disclosure.

[0103] Reference Figure 11 The battery cell according to this embodiment may further include a current collector 400. The current collector 400 may be coupled to a surface of the electrode assembly 100. The current collector 400 may be electrically connected to a second electrode. Specifically, the current collector 400 may be made of metal and substantially formed in the shape of a plate. The current collector 400 may be coupled to a surface of the electrode assembly 100, for example, as... Figure 11 The upper surface of the electrode assembly 100 is shown (in the +Z axis direction). In this case, the current collector 400 can be welded to the second uncoated portion 102 of the electrode assembly 100. Therefore, the current collector 400 can be electrically connected to the second electrode of the electrode assembly 100.

[0104] Furthermore, the edge 410 of the current collector 400 can be welded to the battery canister 200. Specifically, the edge 410 of the current collector can be welded to the second sidewall 212. In this case, when the second sidewall 212 is formed, the edge 410 of the current collector can deform together with the second sidewall 212, so that the edge 410 of the current collector can be welded to the second sidewall 212 while being in close contact with it.

[0105] Furthermore, in this embodiment, the cap 300A can be welded to the second sidewall 212 of the battery canister, which can be the same as or similar to that described in the previous embodiments. However, in this embodiment, since the current collector 400 is separately provided, the cap 300A may not be directly connected to the electrode assembly 100. Therefore, the cap 300A according to this embodiment may not have the aforementioned features. Figure 5 Electrode connection part 312 in the middle.

[0106] Return to reference Figure 3 The battery cell 10 according to this embodiment may further include electrode terminals 500 and a second current collector 600.

[0107] The electrode terminal 500 can be connected to the closed end of the battery can 200, that is, the bottom 220 of the battery can. Specifically, a terminal hole can be formed in the bottom 220, and the electrode terminal 500 can be connected to the terminal hole.

[0108] The second current collector 600 can be soldered to the lower surface of the electrode assembly 100, more specifically, to the first uncoated portion 101. The second current collector 600 can be electrically connected to the first electrode of the electrode assembly 100. The second current collector 600 can be soldered to the electrode terminal 500, such that the electrode terminal 500 can be electrically connected to the first electrode.

[0109] In addition, an insulating member G1 for insulation between the battery can 200 and the electrode terminal 500 and an insulating sheet G2 for insulation between the second current collector 600 and the battery can 200 can be provided.

[0110] In the following text, reference will be made to Figure 3 , Figure 8 and Figure 9 A method for manufacturing a battery cell having the above-described structure is described.

[0111] The battery cell manufacturing method according to this embodiment may include a battery can preparation step, an electrode assembly accommodating step, a cap assembly step, a processing step, and a cap joining step.

[0112] In the battery can manufacturing step, a battery can is prepared. For example, a battery can with... Figure 3 The battery can shown has a structure with sidewalls 210 and a bottom 220. However, in this case, the sidewalls of the battery can extend in the vertical direction, and a second sidewall is not yet formed. Furthermore, electrode terminals 500 can be connected to the bottom.

[0113] In the electrode assembly receiving step, the electrode assembly 100 can be inserted into the battery canister. (Refer to...) Figure 3 The electrode assembly is further described below. The electrode assembly 100 can be manufactured by winding a laminate obtained by sequentially stacking a negative electrode plate, a separator, a positive electrode plate, and a separator at least once. Here, the positive and negative electrode plates can be formed in sheet shape.

[0114] That is, the electrode assembly 100 used in this embodiment can be a wound electrode assembly. In this case, an additional separator for insulation from the battery canister 200 can be provided on the outer surface of the electrode assembly 100. That is, the electrode assembly 100 can be configured as any wound structure known in the prior art, without limitation.

[0115] One or both sides of the positive electrode plate may be coated with a positive electrode active material, and a first uncoated portion 101 without positive electrode active material may be formed at the end of the positive electrode plate. The first uncoated portion 101 may be exposed to the outside of the separator while forming multiple windings around the center of the electrode assembly 100, thereby serving as an electrode tab.

[0116] One or both sides of the negative electrode plate may be coated with a negative electrode active material, and a second uncoated portion 102 without negative electrode active material may be formed at the end of the negative electrode plate. The second uncoated portion 102 may be exposed to the outside of the separator while forming multiple windings around the center of the electrode assembly 100, thereby serving as an electrode tab.

[0117] In other words, the positive electrode plate and the negative electrode plate may each include an uncoated portion of uncoated active material at their longitudinal ends in the winding direction. Furthermore, the first uncoated portion 101 and the second uncoated portion 102 may be configured to face opposite directions.

[0118] Here, any active material known in the art can be used as the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate, without limitation.

[0119] In addition, the membrane can be configured as a single-layer or multi-layer porous polymer membrane made of polymers such as polyolefins (e.g., ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, or ethylene / methacrylate copolymer).

[0120] As another example, the diaphragm can be a conventional porous nonwoven fabric, such as a nonwoven fabric made of high melting point glass fiber or polyethylene terephthalate fiber.

[0121] At least one surface of the diaphragm may comprise a coating of inorganic particles. Furthermore, the diaphragm itself may be formed from a coating of inorganic particles. The particles constituting the coating may have a structure in which they are bonded to a binder, resulting in interstitial volumes between adjacent particles.

[0122] For example, notches can be formed at predetermined intervals in the first uncoated portion 101 and the second uncoated portion 102 to form flag-shaped notched tabs. In the wound electrode assembly 100, the notched tabs can be bent and flattened radially. The notched tabs can be bent radially inward or outward. The notched tabs can be bent individually during the winding of the laminate to form the wound electrode assembly 100. Alternatively, after winding the laminate to form the wound electrode assembly, all the notched tabs can be bent at once. The notched tabs of the first uncoated portion 101 and the notched tabs of the second uncoated portion 102 are bent and overlapped in the radial direction, and planes substantially perpendicular to the axial direction can be provided at the two axial ends of the electrode assembly 100.

[0123] In the cap assembly step, the cap 300 can be assembled by inserting the cap 300 into the other end (i.e., the open end) of the battery can 200. In this case, the cap 300 can be inserted while the elastic deformation portion 330 is deformed (i.e., press-fitted), thereby allowing the abutment portion 320 of the cap to fit tightly against the side wall portion 210 of the battery can.

[0124] During the processing step, a portion of the sidewall portion 210 is pressed inward, resulting in a portion of the sidewall portion 210 (i.e., the second sidewall 212) undergoing plastic deformation, thereby reducing the inner diameter. The above processing can be achieved through methods such as... Figure 8 and Figure 9 The rolling method described herein is used for execution. During the processing step, a portion of the sidewall portion (i.e., the second sidewall 212) undergoes plastic deformation, thereby reducing its inner diameter. In this process, the abutment portion 320 of the cap and the second sidewall 212 can fit tightly against each other.

[0125] In the cap joining step, the battery canister 200 and the cap 300 can be joined, i.e., welded. Specifically, during the above processing steps, the abutment portion 320 of the cap and the second sidewall 212 of the battery canister can be tightly fitted together, and in this state, the abutment portion 320 and the second sidewall 212 can be welded. For example, the abutment portion 320 and the second sidewall 212 can be welded by irradiating the interface where the abutment portion 320 intersects with the second sidewall 212 with a laser beam. In particular, the cap is provided with an elastic deformation portion 330, which can provide elastic force to ensure that the abutment portion 320 and the second sidewall 212 are tightly fitted together. Therefore, even during laser welding, the abutment portion 320 can be tightly fitted together with the second sidewall 212, thereby improving the welding quality between the abutment portion and the second sidewall.

[0126] Figure 12 This is a diagram illustrating a battery pack according to an embodiment of the present disclosure. Figure 13 It shows including Figure 12 A diagram of a vehicle with a battery pack.

[0127] Reference Figure 12 The battery pack 1 according to this disclosure may include at least one of the battery cells 10 described above. Furthermore, the battery pack 1 according to this disclosure may include a battery pack housing 1a capable of accommodating one or more battery cells 1. The battery pack 1 can be constructed using a battery module as an intermediate component, or, as shown, can be constructed without a battery module. Since the battery cell 10 has a large volume, there are no particular difficulties in implementing the battery pack 1 even without using an intermediate structure such as a battery module.

[0128] In addition to the battery cell 10, the battery pack 1 may also include various components of the battery pack 1 known at the time of filing of this disclosure, such as BMS, relays, current sensors, etc.

[0129] See Figure 13 The vehicle V according to this disclosure may include at least one battery pack 1 according to this disclosure.

[0130] The battery pack 1 according to this disclosure can be applied to vehicles such as electric vehicles or hybrid vehicles. That is, the vehicle V according to this disclosure may include the battery cell 10 according to this disclosure or the battery pack 1 according to this disclosure.

[0131] Battery packs and vehicles, including those using battery cells according to this disclosure, can share the advantages of the battery cells.

[0132] As described above, although this disclosure has been described with reference to limited embodiments and drawings, this disclosure is not limited thereto, and various modifications and variations are possible without departing from the technical spirit of this disclosure and the equivalent scope of the claims described below by those skilled in the art to which this disclosure pertains.

[0133] [Description of reference numerals in the attached figures]

[0134] V: Vehicle

[0135] 1: Battery pack

[0136] 10: Battery cells

[0137] 100: Electrode assembly

[0138] 200: Battery Canister

[0139] 210: Side wall portion

[0140] 211: First sidewall

[0141] 212: Second sidewall

[0142] 220: Bottom

[0143] 300: Hat

[0144] 310: Main Body

[0145] 311: Supporting surface

[0146] 312: Electrode connection part

[0147] 313: Exhaust section

[0148] 320: Contact Department

[0149] 330: Elastic deformation part

[0150] 331: Curved section

[0151] 331a: Gap

[0152] 332: Inclined section

[0153] 400: Current collector

[0154] 500: Electrode terminal

[0155] 600: Second current collector

[0156] G1: Insulating component

[0157] G2: Insulating sheet

Claims

1. A battery cell, the battery cell comprising: An electrode assembly is constructed by winding a first electrode, a second electrode, and a diaphragm inserted between the first electrode and the second electrode around a winding shaft; A battery can having a sidewall portion and a bottom, the sidewall portion being hollow, the bottom being connected to one axial end of the sidewall portion, and the battery can accommodating the electrode assembly through the other axial end of the sidewall portion; as well as A cap that covers the other axial end of the battery can. The sidewall portion includes a first sidewall extending axially from the edge of the bottom and a second sidewall extending from the first sidewall and having an inner diameter smaller than that of the first sidewall. The cap is connected to the inner surface of the second sidewall.

2. The battery cell according to claim 1, wherein The second sidewall is formed to slope inward from the first sidewall.

3. The battery cell according to claim 1, wherein, The second sidewall has a first portion that is formed to be inclined inward from the first sidewall and a second portion that is formed to extend axially from the first portion.

4. The battery cell according to claim 1, wherein The cap is configured such that the portion attached to the second sidewall is elastically biased in the direction in which it fits tightly against the second sidewall.

5. The battery cell according to claim 4, wherein The cap includes: The main body covers the upper side of the electrode assembly; The abutting portion, which is tightly fitted to the second sidewall; and An elastically deformable portion connects the main body and the abutment portion, and provides an elastic force that causes the abutment portion to fit tightly against the second sidewall.

6. The battery cell according to claim 5, wherein The elastically deformable portion includes a curved portion and an inclined portion. The curved portion extends from the abutting portion and has a curved structure that changes the direction of extension. The inclined portion extends from the end of the curved portion and overlaps at least partially with the abutting portion based on the axial direction.

7. The battery cell according to claim 6, wherein, The curved portion has a notch, and when an external force is applied, the curved portion deforms with reference to the notch.

8. The battery cell according to claim 7, wherein The cap includes an exhaust section for venting air, the exhaust section being located in the inner region of the curved portion.

9. The battery cell according to claim 1, wherein, The cap is attached to one side surface of the electrode assembly for electrical connection to the electrode assembly.

10. A battery pack comprising battery cells according to any one of claims 1 to 9.

11. A vehicle comprising the battery pack according to claim 10.

12. A method for manufacturing a battery cell, the method comprising the following steps: A battery can manufacturing step for preparing a battery can, wherein the battery can has a side wall portion and a bottom, the side wall portion is formed into a hollow shape, and the bottom is connected to an axial end of the side wall portion; Electrode assembly receiving step: inserting the electrode assembly into the battery can through the other axial end of the sidewall portion; The cap assembly step involves inserting the cap into the other axial end of the sidewall portion; A processing step that plastically deforms a portion of the sidewall portion inward to reduce the inner diameter of the sidewall portion; as well as The cap joining step involves joining the reduced inner diameter portion of the sidewall to the edge of the cap.

13. The method for manufacturing battery cells according to claim 12, wherein In the processing step, the other axial end of the sidewall portion is processed to be inclined inward.

14. The method for manufacturing battery cells according to claim 12, wherein The cap has a body that covers the upper side of the electrode assembly and an abutment portion that is connected to the body and formed axially to face the sidewall portion. During the processing step, as the inner diameter of the sidewall portion decreases, the sidewall portion and the abutment portion fit together tightly, and In the cap joining step, the abutting part and the side wall part are joined in a tightly fitted state.

15. The method for manufacturing battery cells according to claim 14, wherein The cap also includes an elastically deformable portion configured to connect the body and the abutment portion, and providing an elastic force that causes the abutment portion to fit tightly against the sidewall portion.

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