Battery cell, battery pack and vehicle including same

Abstract

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

Description

Battery cells, battery packs containing the same, and vehicles

[0001] The present invention relates to a battery cell, a battery pack including the same, and a vehicle. The present invention also relates to a method for manufacturing a battery cell. This application claims priority to Korean Patent Application No. 10-2024-0101000, filed July 30, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] Cylindrical battery cells house a jelly-roll-shaped electrode assembly within a cylindrical metal can. These cells are more resistant to shock and temperature than pouch-type batteries. Consequently, demand for these cells in vehicle battery packs is growing.

[0003] The process for manufacturing a battery cell using a cylindrical battery can may include the steps of forming a circular bottom portion and a circular tubular side wall portion connected thereto by deep drawing a metal sheet to manufacture a battery can, accommodating an electrode assembly within the battery can, and then closing the open end of the battery can by covering it with a cap. The closing method may utilize a beading and crimping method, or a method of welding the contact surface of the battery can and the cap. The welding method may utilize seam welding or butt welding.

[0004] In batteries, increasing capacity and reducing costs are critical technological challenges, and seam welding is attracting attention. Preventing damage to the electrode assembly housed within the housing during seam welding can be a critical technical challenge.

[0005] Figure 1 is a drawing showing a process of conventionally welding and finishing the side wall and cap of a battery can.

[0006] When the side wall (1002) and the cap (1001) of the battery can are welded, the internal space of the battery can can be utilized better than when finished with beading and crimping, and thus, there is an advantage of improving the energy density. However, if there is a gap due to tolerance between the side wall (1002) and the cap (1001) of the battery can, the welding laser (L) may be incident on the internal space of the battery can and cause damage to the electrode assembly, and even if welding is performed, the thickness of the weld is reduced and the welding strength is not sufficient. In addition, if precision processing is performed to reduce the tolerance between the cap and the battery can, there is a problem that the unit cost of manufacturing the battery cell increases.

[0007] Even if there is a tolerance between the side wall of the battery can and the cap that has already been formed, if there is a method or a battery cell having such a structure that can narrow the gap between the side wall of the battery can and the cap during the battery cell manufacturing process, it will be possible to protect the electrode assembly while increasing productivity.

[0008] The present invention was created in consideration of the above-described problems, and the problem that the present invention seeks to solve is to provide a battery cell and a manufacturing method thereof that can narrow the gap caused by tolerance when joining the side wall portion of a battery can and the cap.

[0009] Another problem to be solved by the present invention is to provide a battery cell and a method for manufacturing the same in which the battery can and the cap can be strongly adhered to each other without the surfaces where they contact each other being distorted during the process of inserting the cap into the open end of the battery can.

[0010] Another problem that the present invention seeks to solve is to provide a battery pack and a vehicle including such a battery cell.

[0011] The technical objectives of the present invention are not limited to the purposes mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0012] According to one embodiment of the present invention for solving the above-described problem, a battery cell includes: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis; a battery can having a side wall portion formed in a hollow shape and a bottom portion connected to one axial end of the side wall portion, the battery can accommodating the electrode assembly through the other axial end of the side wall portion; and a cap covering the other end of the battery can; wherein the side wall portion includes a first side wall formed to extend in the axial direction from an edge of the bottom portion, and a second side wall formed to extend from the first side wall but having an inner diameter smaller than that of the first side wall, and wherein the cap is coupled to an inner surface of the second side wall.

[0013] According to the present invention, the second side wall can be formed to be inclined inward from the first side wall.

[0014] In addition, the second side wall is characterized by having a first part formed to be inclined inward from the first side wall, and a second part formed to extend in the axial direction from the first part.

[0015] In addition, the cap is characterized in that the portion coupled to the second side wall is configured to be elastically biased in a direction in which it is in close contact with the second side wall.

[0016] In addition, the cap is characterized by having a body portion covering the upper side of the electrode assembly, a mating portion that is in close contact with the second side wall, and an elastic deformation portion that connects the body portion and the mating portion and provides elasticity so that the mating portion is in close contact with the second side wall.

[0017] In addition, the elastic deformation part is characterized by including a curved part having a curved structure that extends from the abutment part but has a curved structure such that the extension direction is changed, and an inclined part that extends from an end of the curved part and overlaps at least a portion of the abutment part with respect to the axial direction.

[0018] In addition, a notch is formed in the curved part, and the curved part is characterized in that it is deformed based on the notch when an external force is applied.

[0019] In addition, the cap is characterized in that it is positioned in the inner region of the curved part and has a vent for venting.

[0020] In addition, the cap is characterized in that it is coupled to one side of the electrode assembly and is electrically connected to the electrode assembly.

[0021] A battery pack according to one embodiment of the present invention may include a battery cell according to one embodiment of the present invention.

[0022] A vehicle according to one embodiment of the present invention for solving the above-described problem may include a battery pack according to one embodiment of the present invention.

[0023] A battery cell manufacturing method according to the present invention is characterized by including a battery can preparation step of preparing a battery can having a side wall portion formed in a hollow shape and a bottom portion connected to one axial end of the side wall portion; an electrode assembly receiving step of inserting an electrode assembly into the inside of the battery can through the other end of the side wall portion; a cap assembling step of inserting a cap into the other end of the side wall portion; a processing step of plastically deforming a portion of the side wall portion in an inward direction to reduce the inner diameter of the side wall portion; and a cap joining step of joining a portion of the side wall portion having a reduced inner diameter to an edge of the cap.

[0024] According to the present invention, in the processing step, the other end of the side wall portion is processed so as to be inclined inward.

[0025] In addition, the cap has a body portion covering the upper side of the electrode assembly, and a mating portion connected to the body portion and formed in the axial direction to face the side wall portion, and in the processing step, as the inner diameter of the side wall portion is reduced, the side wall portion and the mating portion are brought into close contact, and in the cap joining step, the mating portion and the side wall portion are joined in a close state.

[0026] In addition, the cap is characterized in that it further includes an elastic deformation portion that connects the body portion and the mating portion and provides elasticity so that the mating portion adheres closely to the side wall portion.

[0027] According to one aspect of the present invention, since the side wall portion of the battery can is press-formed radially inward, even if there is a gap due to tolerance between the edge of the cap and the side wall portion of the battery can, the battery can and the cap can be contacted together afterwards.

[0028] In particular, the side wall of the battery can can be inclined at a predetermined angle or pressure-molded to have a constant inner diameter, and the edge of the cap can be correspondingly deformed so that the battery can and the cap can be brought into close contact.

[0029] Accordingly, the cap can be joined tightly to the battery can with the edges of the cap in close contact. For example, when laser welding is performed, the laser does not enter the internal space of the battery can, preventing damage to the electrode assembly. Furthermore, there is no concern about the weld thickness being reduced, ensuring sufficient weld strength.

[0030] Additionally, since precision machining to reduce tolerances between the sidewall of the battery can and the cap is not required, the electrode assembly can be protected while increasing productivity without increasing the unit cost of battery cell manufacturing.

[0031] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0032] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0033] Figure 1 is a drawing showing a process of conventionally welding and finishing the side wall and cap of a battery can.

[0034] Figure 2 is a perspective view of a battery cell according to one embodiment of the present invention.

[0035] Figure 3 is a schematic cross-sectional view of the battery cell illustrated in Figure 2.

[0036] Figure 4 is a schematic perspective view of the cap illustrated in Figure 2.

[0037] Figure 5 is a perspective view of the cap illustrated in Figure 4 viewed from below in an upward direction.

[0038] Figure 6 is a schematic cross-sectional view of the cap illustrated in Figure 4.

[0039] Figure 7 is an enlarged view of part A of Figure 3.

[0040] Figure 8 is a drawing for explaining the process of forming the second side wall.

[0041] FIG. 9 is a drawing for explaining a second side wall of a battery cell according to another embodiment of the present invention.

[0042] FIG. 10 is a cross-sectional view of a portion of a battery cell according to another embodiment of the present invention.

[0043] Fig. 11 is a cross-sectional view showing a portion of a battery cell configuration according to another embodiment of the present invention.

[0044] FIG. 12 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0045] FIG. 13 is a drawing for explaining a vehicle including the battery pack of FIG. 12.

[0046] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0047] The present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and with various modifications. However, these embodiments are provided to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. Therefore, the present invention is not limited to the embodiments disclosed below, but should be understood to include all modifications, equivalents, and substitutes included within the technical spirit and scope of the present invention, as well as substitutions or additions of the components of one embodiment with those of another embodiment.

[0048] Furthermore, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar components will be omitted, and the differences will be described.

[0049] The attached drawings are merely intended to facilitate understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification, but should be understood to encompass all modifications, equivalents, and substitutes included within the spirit and technical scope of the present invention. In the drawings, the components may be expressed in exaggerated sizes or thicknesses for ease of understanding, but the scope of protection of the present invention should not be construed as being limited thereby.

[0050] The terminology used in this specification is only used to describe specific implementations or examples and is not intended to limit the present invention. In addition, the singular expression includes the plural expression unless the context clearly indicates otherwise. In the specification, terms such as "comprises" and "consists of" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification. In other words, it should be understood that terms such as "comprises" and "consists of" in the specification do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0051] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0052] Meanwhile, in this specification, terms indicating directions such as up, down, left, right, front, and back may be used, but these terms are only for convenience of explanation, and it is obvious to those skilled in the art that these terms may vary depending on the position, arrangement, rotation, and position of the object being targeted, or the position of the observer.

[0053] In describing the embodiment, the winding axis direction refers to the direction in which the axis forming the winding center of the jelly-roll type electrode assembly extends, the radial direction refers to the direction approaching (centripetal) or moving away (centrifugal) from the axis, and the circumferential direction refers to the direction surrounding the axis.

[0054]

[0055] Fig. 2 is a perspective view of a battery cell according to one embodiment of the present invention. Fig. 3 is a schematic cross-sectional view of the upper and lower portions of the battery cell illustrated in Fig. 2.

[0056] Referring to FIGS. 2 and 3, a battery cell (10) according to the present embodiment may include an electrode assembly (100), a battery can (200), and a cap (300).

[0057]

[0058] The electrode assembly (100) may be in the form of a jelly-roll in which a first electrode, a second electrode, and a separator interposed therebetween are wound in the direction of the winding axis. Specifically, the electrode assembly (100) may be manufactured as a cylindrical jelly-roll by preparing a first electrode, a second electrode, and a separator that extend in the longitudinal direction with a predetermined width, forming a laminated body by stacking the first electrode, the separator, the second electrode, and the separator in that order, and then winding the laminated body around the winding axis. The structure of the electrode assembly (100) is not limited by the embodiment, and may have a winding structure well known in the art.

[0059]

[0060] The battery can (200) may have a side wall portion (210) and a bottom portion (220). The side wall portion (210) may be formed in a hollow cylindrical shape. The bottom portion (220) may be provided at one end in the axial direction of the side wall portion (210), that is, in the up-down direction (Z-axis direction) with reference to FIG. 3. For example, as illustrated in FIG. 3, the bottom portion (220) may be provided at the lower end of the side wall portion (210). The bottom portion (220) may be formed in a disc shape and may be connected to block the lower end of the side wall portion (210). The other end of the battery can (200), that is, the upper end, may be formed in an open structure. In addition, the electrode assembly (100) may be accommodated into the inside of the battery can (200) through the open end, that is, the upper end, of the battery can (200).

[0061] In particular, the side wall portion (210) may include a first side wall (211) and a second side wall (212). The first side wall (211) may be formed to extend axially, i.e., upwardly, from the edge of the bottom portion (220). Accordingly, the inner diameter of the first side wall (211) may be substantially the same as the diameter of the bottom portion (220). The second side wall (212) may be formed to extend from the first side wall (211) but to have an inner diameter smaller than that of the first side wall (211). Specifically, the second side wall (212) may be formed at an upper end, i.e., an open end, based on the entire side wall portion (210). The second side wall (212) may be formed to have an inner diameter smaller than that of the first side wall (211). For example, if the upper end of the side wall portion (210) is plastically deformed inwardly through rolling processing (or roll forming), the inner diameter of the plastically deformed portion can be reduced. Here, the plastically deformed portion of the side wall portion (210) can form the second side wall (212), and the portion that has not been plastically deformed, that is, the lower portion of the second side wall (212), can form the first side wall (211). At this time, the second side wall (212) can be formed while the cap (300) is inserted into the side wall portion (210), and thus the second side wall (212) can be in close contact with the cap (300). This plastic deformation process will be described later.

[0062]

[0063] The cap (300) can be coupled 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 a circular plate shape. The cap (300) can be inserted into the inside of the battery can (200) and coupled 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). Accordingly, the cap (300) can cover, i.e., close, the upper end of the battery can (200).

[0064] In particular, in the present embodiment, the edge of the cap (300) may be joined to the inner surface of the second side wall (212) of the battery can. For example, the edge of the cap (300) may be welded to the second side wall (212).

[0065]

[0066] According to the embodiment of the above-described configuration, the edge of the cap (300) can be welded to the second side wall (212) of the battery can (200). At this time, the second side wall (212) has a reduced inner diameter, that is, a state in which it protrudes inwardly, so that the edge of the battery can (300) and the second side wall (212) can be in close contact. Specifically, since the second side wall (212) is formed by press-forming the side wall portion (210) of the battery can in the radial direction, even if there is a gap due to tolerance between the edge of the cap (300) and the side wall portion (210) of the battery can, the second side wall (212) and the edge of the cap (300) can be in close contact afterwards.

[0067] Accordingly, it is possible to bond the cap (300) with the edge of the cap (200) tightly pressed against the battery can (200). For example, in the case of laser welding, the laser is prevented from entering the internal space of the battery can (200), thereby preventing the electrode assembly (100) from being damaged by the laser. In addition, sufficient welding strength can be achieved without worrying about the weld thickness becoming thin.

[0068] In addition, since precision machining to reduce the tolerance between the side wall portion (210) of the battery can and the cap (300) is not required, the electrode assembly can be protected while increasing productivity without increasing the unit cost of battery cell manufacturing.

[0069]

[0070] In particular, according to the present embodiment, the second side wall (212) may be formed to be inclined inward from the first side wall (211). Specifically, the second side wall (212) may be provided at the upper end of the side wall portion (210). For example, the second side wall (212) may be formed to extend from the first side wall (211), but may be formed to be inclined so that its inner diameter becomes narrower as it extends.

[0071] According to the present embodiment, the second side wall (212) is formed to be inclined inward, so that the second side wall (212) can be in close contact with the edge of the cap (300). Accordingly, the side wall portion (210) of the battery can and the cap (300) can be welded stably and firmly.

[0072] In particular, according to the present embodiment, the surface where the second side wall (212) and the cap (300) come into contact can be formed to be inclined. Accordingly, when welding the second side wall (212) and the cap (300), the laser can be irradiated in an inclined direction rather than a vertical direction, that is, in a direction parallel to the second side wall. Accordingly, even if some of the laser passes through the surface where the battery can (200) and the cap (300) come into contact during the welding process, the laser may only be irradiated to the inner wall of the battery can, more specifically, the boundary point between the first side wall (211) and the second side wall (212), and may not be irradiated to the electrode assembly (100). Therefore, the problem of the electrode assembly being damaged during the welding process can be prevented.

[0073]

[0074] Hereinafter, the specific structures of the battery can and the cap will be described in more detail. Fig. 4 is a schematic perspective view of the cap illustrated in Fig. 2. Fig. 5 is a perspective view of the cap illustrated in Fig. 4 viewed upward from below. Fig. 6 is a schematic cross-sectional view of the cap illustrated in Fig. 4. Fig. 7 is an enlarged view of portion A of Fig. 3. Fig. 8 is a drawing for explaining the process of forming the second side wall. For reference, Figs. 4 to 6 are drawings showing the structure of the cap before it is deformed together with the second side wall during the forming process of the second side wall. In addition, Fig. 7 is a drawing showing the state in which the edge of the cap is welded in a state in which it is deformed inward together with the side wall portion of the battery can, more specifically, the second side wall.

[0075]

[0076] Referring to FIGS. 4 to 8, the cap (300) according to the present embodiment may be configured such that the portion coupled to the second side wall (212) is elastically biased in a direction in which the second side wall (212) is in close contact with the second side wall (212). Specifically, as illustrated in FIG. 8, the edge of the cap (300) may be deformed inwardly together with the second side wall (212) when it is formed inwardly. At this time, the cap (300) is made of a metal material and has a certain level of elasticity, and therefore, the edge of the cap (300) deformed inwardly may try to be restored to its original state, i.e., in the outward direction. In other words, the edge of the cap (300) may be elastically biased in the outward direction, i.e., in a direction in which it is in close contact with the second side wall (212).

[0077] At this time, the elastic force applied to the edge of the cap (300) can be further strengthened depending on the structure of the edge portion of the cap (300) and the portion connected thereto, and this structure will be described in more detail below.

[0078]

[0079] According to the present embodiment, the cap (300) may include a body portion (310), a mating portion (320), and an elastic deformation portion (330). The body portion (310) corresponds to the central portion of the cap (300) and may be arranged on the upper side of the electrode assembly (100) to cover the upper space of the electrode assembly (100). The mating portion (320) may be connected to the body portion (310) by the elastic deformation portion (330). The mating portion (320) may be provided on the outer edge of the cap (300) in the radial direction (X-axis direction). The mating portion (320) may have an overall circular shape and may be formed to have a predetermined width in the axial direction, that is, the up-down direction (Z-axis direction). The abutment portion (320) may be in close contact with the second side wall (212), and may be joined to the second side wall (212) in a close contact state, for example, by welding. The elastic deformation portion (330) is disposed between the body portion (310) and the abutment portion (320), and may connect the body portion (310) and the abutment portion (320). The elastic deformation portion (330) may be for providing elastic force so that the abutment portion (320) is in close contact with the second side wall (212). The elastic deformation portion (330) may be deformed together with the abutment portion (320) when the abutment portion (320) is deformed inwardly together with the second side wall (212). At this time, the elastic deformation portion (330) may be configured to be deformed within the range of elastic deformation rather than plastic deformation, and may also be formed into a structure in which the deformation can occur smoothly.

[0080]

[0081] Specifically, the elastic deformation part (330) may include a curved part (331) and an inclined part (332). The curved part (331) may be formed to extend from the abutment part (320) in a curved shape. Accordingly, the curved part (331) may be extended so that its extension direction changes when it extends. For example, as illustrated in FIG. 6, the curved part (331) may start to extend downward from the abutment part (320) and may extend so that its inclination gradually becomes gentler as it moves away from the abutment part (320). In other words, since the abutment part (320) extends parallel to the axial direction (up-down direction), the inclination of the tangent line of the outer surface of the curved part (331) may gradually decrease from 90 degrees as it moves away from the abutment part (320), and thereafter, the extension direction of the curved part (331) may change upward.

[0082] The inclined part (332) can be extended from the curved part (331). The inclined part (332) can be formed to be inclined so as to face upward in the axial direction and inward in the radial direction. At least a portion of the inclined part (332) can overlap with the abutment part (320) when based on the axial direction, that is, the up-down direction. That is, during the process of extending the curved part (331), the extension direction is gradually changed from the downward direction to the upward direction, and the inclined part (332) is formed to extend as it is from the end of the curved part (331), so that the abutment part (320) and the inclined part (332) can overlap. That is, the abutment part (320) and the inclined part (332) can overlap in the Z-axis direction.

[0083] By this structure, the abutting portion (320), the curved part (331) and the inclined part (332) can be bent to form a U-shaped bend as a whole.

[0084] According to the embodiment of the above configuration, when the second side wall (212) is formed to be inclined inward by being pressed by the roller (R) as illustrated in FIG. 8, the abutment portion (320) can be deformed together with the second side wall (212) while in close contact with it. At this time, the elastic deformation portion (330) can be deformed together so that the abutment portion (320) can be deformed to be inclined. For example, the curved part (331) can be bent in a form in which its radius of curvature becomes smaller, and thus the abutment portion (320) can be tilted to be inclined.

[0085] At this time, the curved part (331) is deformed to have a smaller radius of curvature, but receives a force to straighten out again due to a restoring force, and accordingly, the abutment part (320) connected to the curved part (331) can be elastically biased to adhere to the second side wall (212).

[0086] In addition, the cap (300) having the U-shaped bend portion may be suitable for insertion (press-fitting) through the open end of the battery can (200). Specifically, the curved part (331) and the inclined part (332) may provide a structure in which the cap (300) can be elastically deformed radially inward. Accordingly, when the cap (300) is press-fitted into the open end, the cap (300) can be fitted to the side wall portion (210) as the U-shaped bend portion is compressed and then spread while causing minimal deformation of other parts. Accordingly, a close fit can be secured between the side wall portion (210) of the battery can and the abutment portion (320). In other words, in the process of press-fitting the cap (300) into the battery can (200), they can be strongly pressed together without the abutment portion (320) being distorted.

[0087] Furthermore, in the present invention, even if there is a gap due to a tolerance or shape difference between the abutment portion (320) and the side wall portion (210), the gap between the second side wall (212) and the abutment portion (320) can be removed during the pressure forming process.

[0088]

[0089] Referring again to FIGS. 4 to 7, the cap according to the present embodiment will be further described.

[0090] The body part (310) of the cap may be provided with a support surface (311), an electrode connection part (312), a vent (313), and a liquid injection port (314).

[0091] The support surface (311) may be provided on the inner side of the elastic deformation part (330). Specifically, the support surface (311) may be formed to extend horizontally inward from the end of the inclined part (332). In other words, the support surface (311) may be connected to the radially inner end of the inclined part (332) and may extend horizontally inward in the radial direction from the connection portion. The support surface (311) may provide a flat surface between the inclined surface (332) and the electrode connection portion (312). That is, the surface of the support surface (311) may have a flat ring shape, and may serve as a support surface for supporting the battery cell (10) when the battery cell (10) is erected so that the cap (300) is placed on the floor.

[0092] The electrode connection portion (312) may be a portion that is electrically connected by being coupled to the electrode assembly (100). The electrode connection portion (312) may be positioned inside the support surface (311). The electrode connection portion (312) may be formed by the body portion (310) being sunken in the inner direction of the battery can (200), that is, downward (-Z-axis direction) with reference to FIG. 7. The electrode connection portion (312) may be formed by plastically processing a portion of a cap (300) in the form of a metal plate so that it is sunken downward.

[0093] Referring to FIG. 7, when the cap (300) is inserted into the battery can (200), the cap (300) can be inserted to a position where the bottom surface of the electrode connection portion (312) is in close contact with the upper surface of the electrode assembly (100) accommodated inside the battery can (200), i.e., the second non-coated portion (102). The electrode connection portion (312) and the second non-coated portion (102) can be joined by welding. The welding can be performed by a laser irradiated onto the outer surface of the electrode connection portion (312). The laser can be irradiated along a radial direction to form a weld that extends long in the radial direction.

[0094] In this way, the cap (300) functions as a cover that closes the open end of the battery can (200), while also functioning as a current collector plate of the second electrode (e.g., the negative electrode).

[0095] The joint portion of the electrode connection portion (312) and the second non-conductive portion (102) may extend radially. A plurality of electrode connection portions (312) may be provided and may be radially arranged with respect to the center of the cap (300). A pair of electrode connection portions (312) facing each other with respect to the center of the cap (300) may be aligned in a row.

[0096] Accordingly, the electrode connecting portions (312) can be arranged radially, and a plurality of them can be arranged at equal intervals along the circumferential direction. The electrode connecting portions (312) extend long in the radial direction, and therefore, the electrode connecting portions (312) can be connected to the second non-welded portion (102) arranged from the outer circumference side to the core side of the electrode assembly (100). This welding line widens the current path, and thus significantly reduces the internal resistance of the second electrode.

[0097] By applying the above-described cap (300), the joint portion between the cap (300) and the battery can (200) is simplified, and there is no need to use a current collector plate when electrically connecting the second non-conductive portion (102) to the battery can (200). Therefore, the number of parts and assembly work can be reduced, and the internal volume can be secured to increase the energy density.

[0098] The vent (313) may be for smooth venting during a thermal event of the battery cell (10). The vent (313) may be provided on the inside of the curved part (331). For example, as illustrated in FIG. 6, the vent (313) may be provided on the support surface (311). The vent (313) may be implemented as a thin-walled portion having notched processing on both surfaces of the support surface (311). The strength of the vent (313) may be configured such that it does not deform under the force applied when the cap (300) is pressed into the battery can (200), and is broken when the internal pressure of the battery can (200) suddenly increases. When the vent (313) is broken, the electrode connection portion (312) of the cap (300) and the abutment portion (320) of the cap (300) may be separated. Accordingly, the electrical connection between the electrode connection part (312) connected to the second non-conductive part (102) and the battery can (200) is cut off, and the gas inside the battery can (200) can be discharged to the outside.

[0099] The injection port (314) may be provided in the center of the cap (300). With the open end of the battery can (200) covered by the cap (300), the injection port (314) may be aligned with the winding center hole of the electrode assembly (100) accommodated in the battery can (200).

[0100] The injection port (314) may be provided at a position protruding slightly upward from the bottom surface of the cap (300), i.e., the electrode connection portion (312) of the cap (300). The injection port (314) may be closed by covering a stopper (315). The stopper (315) may have a ball, a plug, or other structure. The edge of the stopper (315) may be sealed with the edge of the injection port (314). The sealing may be performed by seam welding or other known sealing methods.

[0101]

[0102] FIG. 9 is a drawing for explaining a second side wall of a battery cell according to another embodiment of the present invention.

[0103] Referring to Fig. 9, the side wall portion (210) of the battery can according to the present embodiment may include a first side wall (211) and a second side wall (212). The first side wall (211) may be formed to extend axially, i.e., upwardly, from the edge of the bottom portion. The second side wall (212) may be formed to extend from the first side wall (211) but have an inner diameter smaller than that of the first side wall (211).

[0104] Specifically, the second side wall (212) may be formed on the upper end, i.e., the open end, of the entire side wall portion (210). The second side wall (212) may be composed of a first part (212a) and a second part (212b). The first part (212a) may be formed to be inclined inward from the first side wall (211). For example, the first part (212a) may be formed to extend from the first side wall (211), but may be formed to be inclined so that the inner diameter thereof becomes narrower as it extends. The second part (212b) may be formed to extend upward from the end (upper end) of the first part (212a). That is, the second side wall (212) has an inner diameter that is narrower than that of the first side wall (211) in the first part (212a) section, and the second part (212b) can be formed to extend upward with the narrowed inner diameter.

[0105] The structure of the second side wall (212) can be formed by plastically deforming the upper end of the side wall portion (210) inwardly through rolling processing (or roll forming). For example, as illustrated in (a) of FIG. 9, when the upper end of the side wall portion is pressed inwardly through a roller (R), the first part (212a) can be plastically deformed so as to be inclined inwardly. At this time, the second side wall (212) can be formed while the cap (300) is inserted into the side wall portion (210), and thus the second side wall (212) can be brought into close contact with the cap (300).

[0106]

[0107] FIG. 10 is a cross-sectional view of a portion of a battery cell according to another embodiment of the present invention.

[0108] Referring to Fig. 10, the cap (300) according to the present embodiment may further include a notch (331a). The notch (331a) is formed in the elastic deformation portion (330) and may enable the elastic deformation portion (330) to be deformed more smoothly. For example, the notch (331a) may be formed in the curved part (331) of the elastic deformation portion. In particular, the notch (331a) may be formed in a portion where the extension direction of the curved part (331) is changed, that is, a portion where the slope in the tangential direction is close to 0. In other words, the notch (331a) may be formed in the center portion of the U-shaped bend portion. The notch (331a) may be implemented in a manner of forming a 'V'-shaped groove in the curved part (331).

[0109] According to the present embodiment, when the abutment portion (320) is pressed inward, the curved part (331) of the elastic deformation portion can be deformed based on the notch (331a). Specifically, as illustrated in (b) of FIG. 10, when the abutment portion (320) is deformed inward, the curved part (331) can be bent in a form in which its inner diameter becomes smaller. At this time, when the notch (331a) is formed in the curved part (331), the curved part (331) can be deformed as if bent around the notch (331a), and thus the curved part (331) can be deformed better.

[0110] In relation to this, when the side wall portion (210) is formed by pressing inward as shown in FIGS. 8 and 9, the external force transmitted to the cap (300) through the side wall portion (210) is largely alleviated due to deformation of the elastic deformation portion (330), but some of the external force may be transmitted further inward and even to the vent (313). In other words, not only the abutment portion (320) and the elastic deformation portion (330) are deformed by the external force, but deformation may also occur in the vent (313). However, since the vent (313) is configured to have weak strength, it can be deformed or broken very easily. Therefore, there may be a concern that the vent (313) may be damaged during the process of forming the side wall portion (210).

[0111] However, if a notch (331a) is provided in the elastic deformation portion as in the present embodiment, the elastic deformation portion (330) can be deformed in a form that is bent around the notch (331a), thereby blocking or reducing the transmission of external force to the vent (313). Accordingly, it is possible to prevent the vent (313) from being damaged during the process of forming the side wall portion (210).

[0112]

[0113] Fig. 11 is a cross-sectional view showing a portion of a battery cell configuration according to another embodiment of the present invention.

[0114] Referring to FIG. 11, the battery cell according to the present embodiment may further include a current collector plate (400). The current collector plate (400) may be coupled to one surface of the electrode assembly (100). The current collector plate (400) may be electrically connected to the second electrode. Specifically, the current collector plate (400) may be made of a metal material and may be formed in an approximately plate shape. The current collector plate (400) may be coupled to one surface of the electrode assembly (100), for example, to the upper surface (+Z-axis direction) of the electrode assembly (100) with reference to FIG. 11. At this time, the current collector plate (400) may be coupled to the second non-coated portion (102) of the electrode assembly (100) by welding. And, by this coupling, the current collector plate (400) may be electrically connected to the second electrode of the electrode assembly (100).

[0115] In addition, the edge (410) of the collector plate (400) can be welded to the battery can (200). Specifically, the edge (410) of the collector plate can be welded to the second side wall (212). At this time, the edge (410) of the collector plate can be deformed together with the second side wall (212) when the second side wall (212) is formed, and thus the edge (410) of the collector plate can be welded in a state of being in close contact with the second side wall (212).

[0116] And, in the case of this embodiment, the cap (300A) may be welded to the second side wall (212) of the battery can, which may be the same or similar to the embodiment described above. However, in the case of this embodiment, the current collector plate (400) is provided separately, so the cap (300A) may not be directly connected to the electrode assembly (100). Accordingly, the cap (300A) according to this embodiment may not be provided with the electrode connection portion (312) described above in FIG. 5.

[0117]

[0118] Again, referring to FIG. 3, the battery cell (10) according to the present embodiment may further include an electrode terminal (500) and a second collector plate (600).

[0119] The electrode terminal (500) can be coupled to the closed end of the battery can (200), i.e., the bottom portion (220) of the battery can. Specifically, a terminal hole can be formed through the bottom portion (220), and the electrode terminal (500) can be coupled to this terminal hole.

[0120] The second collector plate (600) can be welded to the lower surface of the electrode assembly (100), more specifically, to the first non-conductive portion (101). The second collector plate (600) can be electrically connected to the first electrode of the electrode assembly (100). The second collector plate (600) can be welded to the electrode terminal (500), so that the electrode terminal (500) can be electrically connected to the first electrode.

[0121] 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) may be further provided.

[0122]

[0123] Hereinafter, a method for manufacturing a battery cell having the above-described structure will be described with reference to FIGS. 3, 8, and 9.

[0124] The battery cell manufacturing method according to the present embodiment may include a battery can preparation step, an electrode assembly receiving step, a cap assembling step, a processing step, and a cap bonding step.

[0125]

[0126] In the battery can preparation step, a battery can is prepared. For example, a battery can having the structure illustrated in FIG. 3, i.e., a battery can having a side wall portion (210) and a bottom portion (220), can be prepared. However, at this time, the side wall portion of the battery can extends vertically, and the second side wall is not yet formed. In addition, an electrode terminal (500) may be connected to the bottom portion.

[0127]

[0128] In the electrode assembly receiving step, the electrode assembly (100) can be inserted into the inside of the battery can. Referring to FIG. 3, the electrode assembly will be described in more detail. The electrode assembly (100) can be manufactured by sequentially stacking a negative electrode plate, a separator, a positive electrode plate, and a separator at least once and winding the laminated body. Here, the positive electrode plate and the negative electrode plate can be formed in a sheet shape.

[0129] That is, the electrode assembly (100) applied to the present embodiment may be a coil-type electrode assembly. In this case, an additional separator may be provided on the outer circumferential surface of the electrode assembly (100) for insulation from the battery can (200). That is, the electrode assembly (100) may have a coil-type structure well known in the related technical field without limitation.

[0130] A positive electrode plate may have a positive electrode active material applied to one or both sides thereof, and a first non-conductive portion (101) on which the positive electrode active material is not applied may be formed at an end of the positive electrode plate. The first non-conductive portion (101) may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (100), and may be used as an electrode tab in its own right.

[0131] A negative electrode plate may have a negative electrode active material applied to one or both sides thereof, and a second non-conductive portion (102) on which the negative electrode active material is not applied may be formed at an end of the negative electrode plate. The second non-conductive portion (102) may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (100), and may be used as an electrode tab in its own right.

[0132] That is, the positive and negative plates may each include a non-coated portion that is not coated with an active material at the long end in the winding direction. In addition, the first non-coated portion (101) and the second non-coated portion (102) may be configured to face in opposite directions.

[0133] Here, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate can be used without limitation as long as they are active materials known in the art.

[0134] In addition, the separation membrane may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., which may be used alone or in a laminated manner.

[0135] As another example, the separator may be a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc.

[0136] At least one surface of the membrane may include a coating layer of inorganic particles. Furthermore, the membrane itself may be formed of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound to a binder such that an interstitial volume exists between adjacent particles.

[0137] For example, the first uncoated portion (101) and the second uncoated portion (102) may be formed with notches at a predetermined interval to form flag-shaped notched tabs. In the jelly-roll type electrode assembly (100), the notched tabs may be bent radially and flattened. The notched tabs may be bent radially inward or outward. The notched tabs may be bent one by one during the process of forming the jelly-roll type electrode assembly (100) by winding the laminate. Alternatively, the notched tabs may be bent all at once after the laminate is wound to form the jelly-roll type electrode assembly. The notching tabs of the first plain portion (101) and the notching tabs of the second plain portion (102), which are bent and overlapped in the radial direction in this way, can provide a plane that is substantially perpendicular to the axial direction at each of the axial ends of the electrode assembly (100).

[0138]

[0139] In the cap assembly step, the cap (300) can be assembled by inserting it into the other end of the battery can (200), i.e., the open end. At this time, the cap (300) can be inserted in a form in which the elastic deformation portion (330) is deformed, i.e., in a press-fit form, so that the abutment portion (320) of the cap can be in close contact with the side wall portion (210) of the battery can.

[0140]

[0141] In the processing step, a part of the side wall portion (210) is pressed inward, and accordingly, a part of the side wall portion (210), that is, a part of the second side wall (212), may be plastically deformed and its inner diameter may be reduced. The processing may be performed by a rolling processing method, as described in FIGS. 8 and 9. Through the processing step, a part of the side wall portion, that is, the second side wall (212), may be plastically deformed and its inner diameter may be narrowed, and in this process, the abutment portion (320) of the cap and the second side wall (212) may be closely adhered to each other.

[0142]

[0143] In the cap bonding step, the battery can (200) and the cap (300) can be bonded, i.e., welded. Specifically, in the processing step, the abutment portion (320) of the cap and the second side wall (212) of the battery can are tightly adhered, and in this state, the abutment portion (320) and the second side wall (212) can be welded. For example, welding can be performed by irradiating a laser on the surface where the abutment portion (320) and the second side wall (212) are in contact. In particular, the cap is provided with an elastic deformation portion (330), and this elastic deformation portion can provide elastic force so that the abutment portion (320) is in close contact with the second side wall (212). Therefore, even during the laser welding process, the abutment portion (320) can be closely adhered to the second side wall (212), and thus the welding quality between the abutment portion and the second side wall can be improved.

[0144]

[0145] Fig. 12 is a drawing for explaining a battery pack according to one embodiment of the present invention. Fig. 13 is a drawing for explaining a vehicle including the battery pack of Fig. 12.

[0146] Referring to FIG. 12, a battery pack (1) according to the present invention may include at least one battery cell (10) according to the present invention described above. In addition, the battery pack (1) according to the present invention may include a pack housing (1a) capable of accommodating the at least one battery cell (1). The battery pack (1) may be configured using a battery module, which is an intermediate form of assembly, or may be configured directly without a battery module, as illustrated. Since the battery cell (10) itself has a large volume, there may be no particular difficulty in implementing the battery pack (1) even without using an intermediate structure called a battery module.

[0147] In addition, the battery pack (1) may further include various other components in addition to the battery cells (10), such as components of the battery pack (1) known at the time of application of the present invention, such as a BMS, a relay, a current sensor, etc.

[0148]

[0149] Referring to FIG. 13, a vehicle (V) according to the present invention may include at least one battery pack (1) according to the present invention.

[0150] The battery pack (1) according to the present invention can be applied to automobiles such as electric vehicles or hybrid vehicles. That is, the automobile (V) according to the present invention can include a battery cell (10) according to the present invention or a battery pack (1) according to the present invention.

[0151]

[0152] The above battery pack and vehicle, which are equipped with a battery cell according to the present invention, can have the same advantages as the battery cell.

[0153]

[0154] Although the present invention has been described above with reference to 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 idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0155]

[0156] [Explanation of symbols]

[0157] V: Car

[0158] 1: Battery pack

[0159] 10: Battery cell

[0160] 100: Electrode assembly

[0161] 200: Battery can

[0162] 210: Side wall

[0163] 211: First side wall

[0164] 212: Second side wall

[0165] 220: Bottom

[0166] 300: Cap

[0167] 310: Body

[0168] 311: Support surface

[0169] 312: Electrode connection

[0170] 313: Vent

[0171] 320: The facing part

[0172] 330: Elastic deformation zone

[0173] 331: Curved part

[0174] 331a: Notch

[0175] 332: Slope Part

[0176] 400: Current collector plate

[0177] 500: Electrode terminal

[0178] 600: Second Collection Edition

[0179] G1: Insulating material

[0180] G2: Insulating sheet

Claims

1. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis; A battery can having a side wall formed in a hollow shape and a bottom connected to one axial end of the side wall, and accommodating the electrode assembly through the other axial end of the side wall; and A cap covering the other end of the battery can; The side wall portion has a first side wall formed to extend in the axial direction from the edge of the bottom portion, and a second side wall formed to extend from the first side wall but have an inner diameter smaller than that of the first side wall. A battery cell characterized in that the cap is bonded to the inner surface of the second side wall.

2. In paragraph 1, A battery cell characterized in that the second side wall is formed to be inclined inward from the first side wall.

3. In paragraph 1, A battery cell characterized in that the second side wall comprises a first part formed to be inclined inward from the first side wall, and a second part formed to extend in the axial direction from the first part.

4. In paragraph 1, A battery cell characterized in that the cap is configured such that the portion coupled to the second side wall is elastically biased in a direction in which it is in close contact with the second side wall.

5. In paragraph 4, A battery cell characterized in that the cap has a body portion covering the upper side of the electrode assembly, a mating portion that is in close contact with the second side wall, and an elastic deformation portion that connects the body portion and the mating portion and provides elasticity so that the mating portion is in close contact with the second side wall.

6. In paragraph 5, A battery cell characterized in that the elastic deformation part includes a curved part having a curved structure that extends from the abutment part but has a changed extension direction, and an inclined part that extends from an end of the curved part and overlaps at least a portion of the abutment part with respect to the axial direction.

7. In paragraph 6, A battery cell characterized in that a notch is formed in the above curved part, and the curved part is deformed based on the notch when an external force is applied.

8. In paragraph 7, A battery cell characterized in that the cap is located in the inner region of the curved part and has a vent for venting.

9. In paragraph 1, A battery cell characterized in that the cap is coupled to one side of the electrode assembly and is electrically connected to the electrode assembly.

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

11. A vehicle including a battery pack of Article 10.

12. A battery can preparation step of preparing a battery can having a side wall portion formed in a hollow shape and a bottom portion connected to one axial end of the side wall portion; An electrode assembly receiving step for inserting an electrode assembly into the inside of the battery can through the other end of the side wall portion; A cap assembly step of inserting a cap into the other end of the side wall portion; A processing step of plastically deforming a portion of the side wall portion inward to reduce the inner diameter of the side wall portion; and A battery cell manufacturing method, characterized by including a cap bonding step of bonding a portion of the side wall portion with a reduced inner diameter and an edge of the cap.

13. In paragraph 12, A battery cell manufacturing method characterized in that, in the above processing step, the other end of the side wall portion is processed so as to be inclined inward.

14. In paragraph 12, The cap has a body portion covering the upper side of the electrode assembly, and a mating portion connected to the body portion and formed in the axial direction to face the side wall portion. As the inner diameter of the side wall portion is reduced in the above processing step, the side wall portion and the mating portion are brought into close contact with each other. A battery cell manufacturing method characterized in that, in the above cap bonding step, the mating portion and the side wall portion are bonded in a close contact state.

15. In paragraph 14, A battery cell manufacturing method characterized in that the cap further includes an elastic deformation portion that connects the body portion and the mating portion and provides elasticity so that the mating portion adheres closely to the side wall portion.

Images