Battery cell, manufacturing method of same and battery pack and vehicle including same

Abstract

A battery cell according to an embodiment of the present disclosure includes an electrode assembly; a can accommodating the electrode assembly; and a first electrode terminal electrically connected to the electrode assembly. The first electrode terminal includes a current collector surface positioned on the inner side of the can, a column portion extending from the current collector surface and penetrating the can, and a terminal surface extending from the column portion and positioned on the outer side of the can, wherein the column portion has a first hole formed by penetrating the current collector surface, the terminal surface has a second hole communicating with the first hole and smaller than the first hole, and the second hole is sealed at the surface of the terminal surface.

Description

Battery cells, methods for manufacturing the same, and battery packs and vehicles including such battery cells

[0001] The present invention relates to a battery cell, a method for manufacturing the same, and a battery pack and vehicle including the battery cell. This application claims priority to Korean Patent Application No. 10-2024-0111929, filed August 21, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] Secondary batteries, which boast high applicability across a wide range of product categories and electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electrical power sources. These secondary batteries not only offer the primary advantage of dramatically reducing fossil fuel use but also produce no byproducts from energy use, attracting attention as a new energy source for environmental friendliness and energy efficiency.

[0003] Secondary batteries are assembled into battery modules or battery packs, where multiple battery cells are stacked or layered in a dense structure to provide high voltage and current, and then electrically connected. Typically, a battery module containing at least one battery cell is first constructed, and then other components are added to form a battery pack using this at least one battery module. Recently, battery packs in the cell-to-pack form, where multiple battery cells are housed directly in a pack housing, rather than modularized, have also been manufactured.

[0004] There is a growing demand for metal can-shaped battery cells for automotive battery packs. These cans can be either square or cylindrical. Cylindrical battery cells house a jelly-roll-shaped electrode assembly within the cylindrical can, offering greater shock and temperature resistance than pouch-shaped battery cells.

[0005] The process for manufacturing a battery cell using a cylindrical can may include forming a can by deep drawing a metal sheet to form a circular bottom portion (closed surface) and a circular tubular side wall portion connected thereto, accommodating an electrode assembly within the can, and then closing the open end of the can by covering it with a lid. The closing method may include butt welding or beading and crimping.

[0006] Battery cells using butt welding have the advantage of increasing internal capacity within the same external dimensions compared to cells using beading and crimping methods. However, because welding after filling is difficult, a filler port must be provided in the lead, followed by a process of filling the filler port with welding fluid, and then sealing the port with a sealing component.

[0007] Meanwhile, in conventional battery cells, there are cases where electrode terminals are riveted to the bottom of the can. The electrode terminal is inserted from the outside to the inside of the can through the bottom of the can, and a caulking jig for riveting is inserted from the open end of the can to compress the inner part of the electrode terminal toward the inner side of the bottom of the can. At this time, the caulking jig moves up and down, and the process of compressing the inner part of the electrode terminal toward the outer side in the circumferential direction is repeated several times. The caulking jig pressurizes and forms the inner side of the electrode terminal, and since the inner side of the electrode terminal is deformed by the shape of the caulking jig, it is difficult to form a flat area on the inner side of the electrode terminal. Since the flat area is used as a joint between the electrode terminal and other components, it has been difficult to maximize the joint area in the past. Furthermore, since the electrode terminal is pressed from the inside of the can, if foreign matter is generated during this process, it remains inside the can, making management difficult.

[0008] The present invention has been prepared to solve the problems described above, and the problem to be solved by the present invention is to provide a battery cell with an improved injection structure and a method for manufacturing the same.

[0009] Another problem to be solved by the present invention is to provide a battery cell with improved electrode terminals and a method for manufacturing the same.

[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] According to the present invention for solving the above-described problem, a battery cell includes: an electrode assembly; a can accommodating the electrode assembly; and a first electrode terminal electrically connected to the electrode assembly. The first electrode terminal includes a current collecting surface positioned on the inside of the can, a pillar portion extending from the current collecting surface and penetrating the can, and a terminal surface extending from the pillar portion and positioned on the outside of the can, wherein a first hole is formed through the current collecting surface in the pillar portion, a second hole is formed in the terminal surface, the second hole is communicated with the first hole and is smaller than the first hole, and the second hole is sealed on the surface of the terminal surface.

[0012] In one embodiment, the can may include a side wall portion, a bottom portion connected to one axial end of the side wall portion, an open end provided at the other axial end of the side wall portion, and a lid covering the open end.

[0013] The electrode assembly may be wound with a first electrode and a second electrode with a separator interposed therebetween, and the electrode assembly may be accommodated inside the can such that the non-conductive portion of the second electrode faces the open end.

[0014] A through hole is formed in the above bottom portion, and the first electrode terminal can be electrically connected to the first electrode by passing through the through hole.

[0015] The battery cell may further include a first collector plate configured to be electrically connected to the first electrode, at least a portion of the first collector plate may be coupled to an inner surface of the first electrode terminal, and a hole may be formed in a central portion of the first collector plate that is aligned with the first hole.

[0016] The above-mentioned collector surface may form an inner flange portion extending along the inner surface of the bottom portion from the first side of the column portion, and the above-mentioned terminal surface may form an outer flange portion extending along the outer surface of the bottom portion from the second side of the column portion.

[0017] The inner surface of the above inner flange portion may be provided flat.

[0018] The above current collector surface forms an inner flange portion extending along the inner surface of the bottom portion from the first side of the pillar portion, and the inner flange portion extends radially outward from the first side of the pillar portion disposed inside the can so as to extend radially outward more than the through hole, and can be joined to the first current collector plate.

[0019] The terminal surface may be a plastically processed portion formed by plastically processing a second side protruding from the column portion to the outside of the can to extend radially outwardly, such that an outer flange portion extends from the second side of the column portion along the outer surface of the bottom portion, and the outer flange portion extends radially outwardly more than the through hole.

[0020] The above first electrode terminal may be made of metal, and the terminal surface may be formed by plastic processing of a portion of the pillar portion protruding outward from the can.

[0021] A second hole sealing portion may be formed on the above terminal surface.

[0022] The above second hole sealing portion may be a molten metal solidification portion.

[0023] In one embodiment, the molten metal solidification portion is a portion of the first electrode terminal around the second hole that is melted and then solidified.

[0024] In another embodiment, the device may further include a cap coupled to the outer flange portion to block the second hole.

[0025] The cap may include a substrate portion that contacts the axial surface of the outer flange portion; and an alignment protrusion that extends axially inward from the substrate portion and is inserted into the second hole.

[0026] A terminal gasket may further be included between the first electrode terminal and the can. The terminal gasket may include an outer gasket interposed between the outer flange portion and the outer surface of the bottom portion, an inner gasket interposed between the inner flange portion and the inner surface of the bottom portion, and an intermediate gasket interposed between the pillar portion and the through hole.

[0027] The above lid may have a disc shape so as to block the open end of the can, and may be finished by joining the side wall portion of the can and the edge of the lid.

[0028] A method for manufacturing a battery cell according to the present invention comprises: a can preparation step of assembling a first electrode terminal preform to the bottom portion, the first electrode terminal preform comprising a sidewall portion, a bottom portion connected to one axial end of the sidewall portion, and an open end provided at the other axial end of the sidewall portion; a can preparation step of assembling the first electrode terminal preform to the bottom portion, the first electrode terminal preform comprising a current collector surface positioned inside the can and a pillar portion extending from the current collector surface, penetrating the can and protruding outwardly of the can, and having a first hole formed through the current collector surface at a central portion; an electrode assembly receiving step of receiving the electrode assembly in the can; a lid assembling step of covering and closing the open end of the can with a lid; a step of injecting an electrolyte into the can through the first hole; a step of plastically working the pillar portion protruding outwardly of the can to form a terminal surface extending from the pillar portion and positioned outwardly of the can; and a step of sealing the first hole on a surface of the terminal surface to complete the first electrode terminal.

[0029] The above lid assembly step may include a step of covering the open end of the can with a lid; and a step of joining the side wall portion of the can and the edge contact surface of the lid.

[0030] After electrically connecting the current collecting surface of the first electrode terminal preform and the electrode assembly, the electrode assembly can be accommodated in the can.

[0031] The present invention also provides a battery pack comprising one or more battery cells according to the present invention.

[0032] A vehicle according to the present invention includes a battery pack according to the present invention.

[0033] According to one aspect of the present invention, by using a first electrode terminal preform including a column portion having a first hole, the injection structure can be improved without having to provide a separate injection port in the lead.

[0034] According to one aspect of the present invention, during the process of riveting the first electrode terminal to the can, the first electrode terminal can be secured to the outside of the can. Accordingly, the generation of foreign substances inside the can is suppressed during the manufacturing of the battery cell.

[0035] According to one aspect of the present invention, the welding required to electrically connect the first electrode terminal and the electrode assembly can be performed on the outside of the can, thereby also having the effect of preventing welding debris from entering the inside of the can.

[0036] According to one aspect of the present invention, since the welding area between the first electrode terminal and the first collector plate can be maximized, the amount of current moving between the first electrode terminal and the first collector plate can be increased.

[0037] According to one aspect of the present invention, the vertical height of the electrode assembly can be increased as the height of the first electrode terminal decreases, thereby improving the energy density of the battery cell.

[0038] According to another aspect of the present invention, since it is a battery cell using butt welding, the energy density can be improved compared to a battery cell using a beading and crimping method.

[0039] According to another aspect of the present invention, the joint portion between the lead and the can is simplified, and there is no need to use a current collector plate when electrically connecting the second non-conductive portion of the electrode assembly to the can, thereby reducing the number of parts and assembly work, securing more internal volume, and increasing energy density.

[0040] 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.

[0041] FIG. 1 is a perspective view showing the appearance of a battery cell according to one embodiment of the present invention.

[0042] Figure 2 is a cross-sectional view taken along line II-II' of Figure 1.

[0043] Figure 3 is an enlarged view of part A of Figure 2.

[0044] Figures 4 and 5 are schematic diagrams for explaining a method for manufacturing a battery cell.

[0045] Fig. 6 is a modified example of Fig. 3.

[0046] Fig. 7 is a modified example of Fig. 6.

[0047] Fig. 8 is another modified example of Fig. 3.

[0048] Fig. 9 is another modified example of Fig. 3.

[0049] Figure 10 is an enlarged view of part B of Figure 2.

[0050] Fig. 11 is a modified example of Fig. 10.

[0051] Figure 12 is a partial cutaway perspective view showing an example of a lead that can be applied to Figure 11.

[0052] FIG. 13 is a drawing for explaining a battery pack according to one embodiment of the present invention.

[0053] FIG. 14 is a drawing for explaining a vehicle including the battery pack of FIG. 13.

[0054] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0055] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0056] 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.

[0057] Meanwhile, in the present invention, terms indicating directions such as up, down, left, right, front, and back may be used, but it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0058] For convenience of explanation, the direction along the length of the winding axis of the electrode assembly wound in the jelly-roll shape is referred to as the axial direction in this specification. The direction surrounding the winding axis is referred to as the circumferential direction or the circumferential direction. The direction approaching or moving away from the winding axis is referred to as the radial direction.

[0059] Fig. 1 is a perspective view showing the appearance of a battery cell according to one embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along line II-II' of Fig. 1. Fig. 3 is an enlarged view of part A of Fig. 2.

[0060] Referring to FIGS. 1 to 3, a battery cell (10) includes an electrode assembly (50), a can (100), and a first electrode terminal (200).

[0061] The can (100) is configured to accommodate an electrode assembly (50).

[0062] A can (100) includes a side wall portion (110), a bottom portion (120) connected to one axial end of the side wall portion (110), and an open end provided at the other axial end of the side wall portion (110). The bottom portion (120) has a generally flat shape. The side wall portion (110) may be cylindrical, connected to the bottom portion (120), and extending in the axial direction. The side of the side wall portion (110) that is not connected to the bottom portion (120) may define the open end of the can (100).

[0063] In FIGS. 1 and 2, the bottom portion (120) is illustrated as being included in the top of the can (100), and the open end is illustrated as being included in the bottom of the can (100). The open end may be formed in a portion facing the bottom portion (120) of the can (100). The electrode assembly (50) may be accommodated through the open end formed in the can (100). The open end may be covered with a lid (300). The lid (300) may be joined to the can (100) using butt welding. Therefore, the battery cell (10) can have a larger internal capacity with the same external shape than a battery cell using the beading and crimping methods. Therefore, the energy density can be increased.

[0064] The bottom portion (120) and the side wall portion (110) can be manufactured by forming a metal sheet with a nickel plated surface of steel using a deep drawing process, and trimming the front end of the side wall portion (110) with a punch while holding it with a blank holder. Of course, the material of the can (100) is not limited thereto. The material of the can (100) can be manufactured from a conductive metal, such as aluminum, steel, stainless steel, etc., but is not limited thereto.

[0065] The bottom portion (120) forms a closed surface of the can (100). A through hole (130) is formed in the bottom portion (120), and a first electrode terminal (200) can pass through the through hole (130). The first electrode terminal (200) may be fitted into the bottom portion (120). The first electrode terminal (200) may be riveted and fixed to the bottom portion (120) with a terminal gasket (140) interposed therebetween. The terminal gasket (140) is interposed between the first electrode terminal (200) and the bottom portion (120), sealing the inside and the outside of the can (100) to prevent leakage of the electrolyte, and electrically insulating between the first electrode terminal (200) and the bottom portion (120). The terminal gasket (140) can be fitted between the first electrode terminal (200) and the can (100).

[0066] A part of the first electrode terminal (200) is inserted into the inside of the can (100) and another part is exposed to the outside of the can (100). The first electrode terminal (200) includes a current collecting surface (210) located on the inside of the can (100), a pillar portion (220) extending from the current collecting surface (210) and penetrating the can (100), and a terminal portion (230) extending from the pillar portion (220) and located on the outside of the can (100).

[0067] The current collecting surface (210) is a flat surface. The current collecting surface (210) is a surface facing the electrode assembly (50). Preferably, the thickness of the current collecting surface (210) is constant in the radial direction.

[0068] The first electrode terminal (200) may be made of metal, and the terminal surface (230) may be formed by plastic processing of the portion of the pillar portion (220) that protrudes outward from the can (100). The first electrode terminal (200) may be made of aluminum. When the material of the first electrode terminal (200) is aluminum, 10-series aluminum, which facilitates plastic processing and has relatively low electrical resistance, may be used.

[0069] The terminal surface (230) is a flat portion. Preferably, the thickness of the terminal surface (230) is constant in the radial direction.

[0070] A first hole (H) is formed in the column portion (220) through the current collecting surface (210). The first hole (H) may extend axially to the center of the current collecting surface (210) and the column portion (220). The first hole (H) is sealed on the surface of the terminal surface (230). For example, a second hole sealing portion (240) may be formed in the terminal surface (230).

[0071] In particular, a second hole (H') that is smaller than the first hole (H) and communicates with the first hole (H) is formed on the terminal surface (230), and the second hole (H') is sealed on the surface of the terminal surface (230) by a second hole sealing portion (240).

[0072] The second hole (H') is concentric with the first hole (H) and has an inner diameter less than or equal to the inner diameter of the first hole (H). The inner diameter of the first hole (H) is constant along the axial direction, but the inner diameter of the second hole (H') may not be constant along the axial direction. For example, the second hole (H') may have a shape in which the inner diameter decreases as it approaches the surface of the terminal surface (230).

[0073] According to one embodiment of the present invention, during the process of riveting the first electrode terminal (200) to the can (100), the first electrode terminal (200) can be fixed on the outside of the can (100). Conventionally, riveting is performed on the inside of the can, but according to one embodiment of the present invention, riveting can be performed on the outside of the can (100). Accordingly, there is an effect of suppressing the occurrence of foreign substances inside the can (100) during the manufacturing of the battery cell (10).

[0074] The first electrode terminal (200) is electrically connected to the electrode assembly (50). The current collecting surface (210) of the first electrode terminal (200) is used for electrical connection. Unlike the conventional method, the current collecting surface (210) is not deformed by the caulking jig and can maintain a flat surface. The flat surface is used as a joint that is electrically connected to the electrode assembly (50), and unlike the conventional method, the area of ​​this joint can be made sufficiently large.

[0075] The electrode assembly (50) may be in the form of a jelly-roll in which a first electrode and a second electrode are wound around a winding shaft with a separator interposed therebetween. Here, the first electrode and the second electrode may be formed in a sheet shape. An additional separator may be provided on the outer circumferential surface of the electrode assembly (50) for insulation from the can (100).

[0076] The first electrode may be a positive electrode plate and the second electrode may be a negative electrode plate. The positive electrode plate may have a positive electrode active material applied to one or both sides thereof, and a first uncoated portion (52) on which the positive electrode active material is not applied may be formed at an end of the positive electrode plate. The first uncoated portion (52) may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (50) and may be used as an electrode tab in itself. The negative electrode plate may have a negative electrode active material applied to one or both sides thereof, and a second uncoated portion (54) on which the negative electrode active material is not applied may be formed at an end of the negative electrode plate. The second uncoated portion (54) may be exposed to the outside of the separator while forming a plurality of winding turns based on the center of the electrode assembly (50) and may be used as an electrode tab in itself. That is, the positive electrode plate and the negative electrode plate may each include a uncoated portion on which the active material is not coated at a long end in the winding direction. In addition, the first uncoated portion (52) and the second uncoated portion (54) may be configured to face in opposite directions. The first uncoated portion (52) may be housed inside the can (100) at one end in the direction of the winding axis, and the second uncoated portion (54) may be housed at the other end in the direction of the winding axis.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] For example, the first plain region (52) and the second plain region (54) may be notched at a predetermined interval to form flag-shaped notched tabs. In the jelly-roll-shaped electrode assembly (50), 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 winding the laminate to form the jelly-roll-shaped electrode assembly (50). Alternatively, the notched tabs may be bent all at once after the laminate is wound to form the jelly-roll-shaped electrode assembly. The notched tabs of the first plain region (52) and the notched tabs of the second plain region (54), which are bent radially and overlapped in this way, may provide a plane that is substantially perpendicular to the axial direction at each of the axially opposite ends of the electrode assembly (50).

[0082] The electrode assembly (50) can be accommodated inside the can (100) such that the second non-conductive portion (54) faces the open end. Accordingly, the first electrode terminal (200) can be electrically connected to the first electrode of the electrode assembly (50) by passing through the through hole (130).

[0083] The battery cell (10) may further include a first collector plate (60) configured to be electrically connected to the first electrode and a second collector plate (70) configured to be electrically connected to the second electrode. The first collector plate (60) and the second collector plate (70) may be joined to a substantially flat surface provided by bending notched tabs exposed at both axial ends of the electrode assembly (50). The joining may be performed using a method such as resistance welding, ultrasonic welding, or laser welding.

[0084] At least a portion of the first collector plate (60) may be joined to the inner surface of the first electrode terminal (200). Specifically, the first collector plate (60) may be joined to the collector surface (210) of the first electrode terminal (200) by welding or the like.

[0085] A pouring hole (62) aligned with the first hole (H) may be formed in the center of the first collector plate (60). During the manufacturing process, the electrolyte may be injected into the interior of the can (100) through the first hole (H). Since the pouring hole (62) of the first collector plate (60) is aligned with the first hole (H), the electrolyte may flow into the electrode assembly (50) through the pouring hole (62).

[0086] Additionally, the battery cell (10) may further include an insulator (80).

[0087] An insulator (80) may be provided between the first collector plate (60) and the inner surface of the bottom portion (120). The insulator (80) prevents contact between the first collector plate (60) and the can (100). The insulator (80) may also be interposed between the inner surface of the side wall portion (110) and the electrode assembly (50). That is, the insulator (80) may also be interposed between the first non-conductive portion (52) and the can (100). This is to prevent contact between the first non-conductive portion (52) extending toward the bottom portion (120) of the can (100) and the inner surface of the can (100).

[0088] Referring to FIG. 3, the pillar portion (220) extends in the axial direction. The current collecting surface (210) forms an inner flange portion (212) extending along the inner surface of the bottom portion (120) from the first side of the pillar portion (220). The terminal surface (230) may form an outer flange portion (232) extending along the outer surface of the bottom portion (120) from the second side of the pillar portion (220).

[0089] The inner surface of the inner flange portion (212) may be provided flat. The inner flange portion (212) may be provided parallel to the bottom portion (120).

[0090] The inner flange portion (212) extends radially outward from the first side of the pillar portion (220) arranged inside the can (100) so as to extend radially outward more than the through hole (130), and can be joined to the first collector plate (60).

[0091] The outer flange portion (232) may be a plastically processed portion formed by plastically processing the second side protruding from the column portion (220) to the outside of the can (100) so as to extend outward in the radial direction more than the through hole (130).

[0092] The above-mentioned plastic processing portion can be formed by spinning processing. In this way, the device for riveting the first electrode terminal (200) can be a spinning device located on the outside of the can (100).

[0093] The lead (300) can be electrically connected to the can (100). The can (100) can be electrically connected to the second collector plate (70). Accordingly, the first electrode terminal (200) can have a first polarity, and the can (100) can have a second polarity. In particular, the bottom portion (120) of the can (100) and the side wall portion (110) connected thereto can both have the second polarity. Accordingly, the can (100) can have both the first electrode terminal (200) and the second electrode terminal (290) arranged at one axial end, for example, at the bottom portion (120). Then, the can (100) can have both the bus bar connected to the first electrode terminal (200) and the bus bar connected to the second electrode terminal (290) positioned at one axial end of the can (100). In one example, the first electrode terminal (200) may be a positive terminal, and the second electrode terminal (290) may be a negative terminal. Of course, the opposite may also be the case. Therefore, the battery cell (10) according to the present invention can simplify the electrical connection structure by connecting both the positive and negative poles in one direction when electrically connecting a plurality of battery cells (10). In addition, the battery cell (10) according to the present invention has a structure in which most of the bottom portion (120) of the can (100) can be used as the second electrode terminal (290), and thus has the advantage of securing a sufficient area for welding components for electrical connection.

[0094] Preferably, the battery cell (10) may be, for example, a cylindrical secondary battery having a form factor ratio (ratio of diameter to height) of greater than about 0.4. Preferably, the diameter of the battery cell (10) may be 40 mm to 50 mm, and the height may be 60 mm to 130 mm. The form factor of the battery cell (10) may be, for example, 46110, 4875, 48110, 4880, or 4680.

[0095] The battery cell (10) described with reference to FIGS. 1 to 3 can be manufactured according to the following manufacturing method, and FIGS. 4 and 5 are schematic diagrams for explaining the battery cell manufacturing method.

[0096] Referring to FIG. 4, first, a can (100) having a side wall portion (110), a bottom portion (120) connected to one axial end of the side wall portion (110), and an open end provided at the other axial end of the side wall portion (110) is prepared, and a first electrode terminal preform (200') and an electrode assembly (50) are assembled to the can (100).

[0097] Compared to the case where the can with the electrode terminal riveted is delivered from an external supplier, the entire process of assembling other parts into the can (100) can be carried out on the production line, and can be managed as an internal management item, which can help improve quality.

[0098] For example, as illustrated in FIG. 4, the first electrode terminal preform (200') may include a current collecting surface (210) located on the inside of the can (100) and a pillar portion (220) extending from the current collecting surface (210), penetrating the can (100), protruding to the outside of the can (100), and having a first hole (H) formed in the center penetrating the current collecting surface (210).

[0099] The current collector surface (210) may extend parallel to the bottom portion (120). The column portion (220) may extend perpendicular to the current collector surface (210) from the current collector surface (210) toward the outside of the can (100). The column portion (220) may extend in a direction parallel to the axial direction of the electrode assembly (50).

[0100] The pillar (220) may have a hollow pipe shape inside to define the first hole (H).

[0101] Conventionally, an electrode terminal is inserted from the outside to the inside of the can by penetrating the bottom of the can, and a caulking jig for riveting is inserted from the open end of the can to press the inside of the electrode terminal toward the inside of the bottom of the can. According to this method, the coating jig must be inserted into the inside of the can, and because the internal space of the can is narrow, there is a limitation that it is difficult to perform the up-and-down movement of the caulking jig accurately and efficiently. According to the present invention, the first electrode terminal preform (200') has a portion where the current collecting surface (210) extends radially outward compared to the through hole (130) and interferes with the bottom portion (120) of the can (100), and the pillar portion (220) has a portion that protrudes from the inside to the outside of the can (100). Accordingly, by inserting the first electrode terminal preform (200') from the inside of the can (100), the first electrode terminal preform (200') can be prevented from being separated from the bottom portion (120) through the current collecting surface (210) and the pillar portion (220) can be plastically processed from the outside of the can (100). Accordingly, an accurate and efficient riveting operation can be performed from the outside of the can (100) using a spinning device or the like.

[0102] In the present invention, the first electrode terminal preform (200') is first assembled to the bottom portion (120), and then the electrode assembly (50) is accommodated in the can (100), and then the current collecting surface (210) of the first electrode terminal preform (200') and the electrode assembly (50) are electrically connected. A first current collecting plate (60) can be used for the electrical connection between the current collecting surface (210) and the electrode assembly (50).

[0103] As another example, the current collecting surface (210) of the first electrode terminal preform (200') and the electrode assembly (50) may be first electrically connected, and then the first electrode terminal preform (200') may be assembled to the bottom portion (120) while accommodating the electrode assembly (50) in the can (100). The first electrode terminal preform (200') and the first current collecting plate (60) may be first welded, and then the first current collecting plate (60) may be welded to the first non-conductive portion (52) of the electrode assembly (50) to form an electrical connection, and then the first electrode terminal preform (200') may be inserted into the through hole (130) of the bottom portion (120).

[0104] Conventionally, electrode terminals are riveted inside the can, and then the flat surface of the electrode terminal and the current collector plate are welded inside the can. A welding horn tip is inserted into a hole formed in the center of the winding of the electrode assembly to weld the electrode terminal and the current collector plate. However, spatter generated during welding can damage the separator and reduce battery capacity and lifespan, so weak welding may be necessary. Furthermore, because it is difficult to reduce the diameter of the welding horn tip, there is a limit to increasing the energy density of the electrode assembly.

[0105] In contrast, according to an embodiment of the present invention, since all welding for electrical connection between the first electrode terminal preform (200') and the electrode assembly (50) can be performed on the outside of the can (100), welding debris can be prevented from entering the inside of the can (100), issues related to weak welding can be resolved, and the hole size at the center of the winding can be made smaller without having to consider the diameter of the welding horn tip, thereby increasing the energy density.

[0106] Furthermore, even if debris is generated during welding, the debris does not enter the can (100), thereby preventing damage to the separator of the electrode assembly (50). Furthermore, issues related to reduced battery capacity and lifespan can be resolved. Furthermore, since welding is performed outside the can (100), various welding methods, such as laser welding and ultrasonic welding, can be utilized.

[0107] When using ultrasonic welding, the horn must vibrate when it touches the contact area. However, in the conventional method of welding on the inside of the can, the horn must be longer than the length of the hole formed in the center of the winding, so there is a high risk of the horn breaking if strong vibration occurs in a straight or zigzag direction. Considering this, a method in which the horn rotates can be applied, but even in this case, there are problems such as the generation of many burrs and the difficulty in confirming the presence of partially unbonded areas. Moreover, in the case of ultrasonic welding, problems may also arise due to foreign substances (metal shavings) generated during welding.

[0108] In the present invention, since welding is performed from the outside of the can (100), ultrasonic welding can be performed using a short horn, and strong vibrations can be applied. In addition, the area to be joined by welding can be observed from the outside, and welding can be performed without any unjoined area. In addition, foreign substances generated during welding do not enter the battery, so there is no problem.

[0109] In order to perform laser welding on the inside of a conventional can, the optical system of the laser welding device must be configured so that the laser beam does not stray from the hole formed in the center of the coil, and the laser must be well focused to a length as long as the hole formed in the center of the coil. Since the laser beam must pass through the hole formed in the center of the coil, it is difficult to prevent damage to the surrounding electrode assembly during the welding process. In the present invention, since welding is performed on the outside of the can (100), the optical system of the laser welding device does not need to be specially changed or upgraded, and since the laser beam does not pass around the electrode assembly (50), there is no damage to the electrode assembly (50). Therefore, laser welding with good welding strength can be conveniently used for joining the first electrode terminal preform (200'), the first collector plate (60), and the electrode assembly (50), which is preferable. In the present invention, by applying laser welding, deformation due to contact pressure welding such as resistance welding is prevented, which is advantageous not only for ensuring quality and performance but also for increasing product yield. Laser welding eliminates the need for welding rods or horns, thereby improving production efficiency, reducing production costs, and shortening manufacturing process times. Furthermore, laser welding offers higher bond strength than ultrasonic welding and more consistent weld performance and quality than resistance welding.

[0110] When inserting the electrode assembly (50) into the can (100), the second collector plate (70) may be connected to the electrode assembly (50) or may not be connected.

[0111] Afterwards, the open end of the can (100) is covered with a lid (300) and finished. At this time, after covering the open end of the can (100) with the lid (300), the side wall (110) of the can (100) and the edge contact surface of the lid (300) can be joined.

[0112] Before that, a step of connecting the second collector plate (70) and the can (100) may be further included. And, a step of connecting the second collector plate (70) and the lead (300) may be further included.

[0113] After joining the can (100) and the lead (300), an electrolyte is injected into the can (100) through the first hole (H).

[0114] Next, as shown in FIG. 5, the column portion (220) protruding to the outside of the can (100) is plastically processed by spinning, so that a terminal surface (230) extending from the column portion (220) and positioned on the outside of the can (100) is formed, as shown in FIG. 3.

[0115] Spinning involves applying rotational force to the desired riveting area, thereby compressing it. Spinning offers the advantage of reducing the number of process management points required and reducing equipment investment costs compared to conventional multi-step riveting methods.

[0116] A spinning device (400) used in spinning processing may include a spinning tool (410) and a spinning body (420). The spinning body (420) refers to the main body of the spinning device (400) that provides rotational force to the spinning tool (410). The spinning tool (410) rotates at high speed and contacts the upper portion (and one side of the upper portion) of the column portion (220) protruding from the first electrode terminal preform (200') to the outside of the can (100), thereby deforming the shape of one side of the column portion (220). As a result, the entire protruding portion of the column portion (220) is plastically deformed by the spinning tool (410) to become an external flange portion (232), and may have a shape that presses and holds the bottom portion (120) and the terminal gasket (140).

[0117] In this process, the column part (220) can be plastically deformed not only radially outward but also radially inward, so that the inner diameter of the first hole (H) in the center of the column part (220) can be reduced, and the column part (220) can be deformed so that only the second hole (H') smaller in size than the first hole (H) remains.

[0118] Inside the can (100), the electrode assembly (50) and the first electrode terminal preform (200') fill the internal space of the can (100), so that the column part (220) can be plastically processed from the outside of the can (100) through a spinning device (400) without placing a separate jig inside the can (100). At this time, a mold (not shown) can be further placed around the column part (220) so that the deformation of the column part (220) can be constantly controlled so that the diameter of the external flange part (232) can be precisely set.

[0119] The above mold is aligned with the column part (220) and has a hole having a larger inner diameter than the column part (220), so that when the spinning tool (410) deforms the column part (220), the part being plastically processed touches the inner surface of the mold and does not expand any further.

[0120] According to this embodiment, the diameter of the outer flange portion (232) is regulated by the mold, and the dimensions of the terminal surface (230) can be formed accurately and consistently even though deformation of the first electrode terminal preform (200') for riveting occurs outside the can (100).

[0121] In this way, according to the present invention, in the process of riveting the first electrode terminal (200) to the can (100), the first electrode terminal (200) can be fixed on the outside of the can (100). Accordingly, there is an effect of suppressing the occurrence of foreign substances inside the can (100) during the manufacturing of the battery cell (10).

[0122] And, conventionally, it is difficult to maximize the flat surface area of ​​the electrode terminal. In contrast, the first electrode terminal (200) of the present invention maintains the flat surface without any other processing being performed on the current collecting surface (210) while the current collecting surface (210) is made flat, as shown in detail in FIG. 3, and thus the bonding area with the first current collecting plate (60) can be maximized.

[0123] Furthermore, in the case of an embodiment of the present invention, as shown in FIG. 3, the diameter (S) of the current collecting surface (210) can be enlarged to a degree that it becomes a circular plate having an area corresponding to the first non-conductive portion (52) of the electrode assembly (50) to the extent that the first current collecting plate (60) is not necessary.

[0124] For example, in the case of a form factor 4680 battery cell, when the diameter of the flat part of a conventional electrode terminal is about 4 cm, the diameter (S) of the current collecting surface (210) of the present embodiment can be expanded to about 7 cm. The bonding area between the current collecting surface (210) and the first current collecting plate (60) can be larger than in the conventional case. In this way, the welding area between the first electrode terminal (200) and the first current collecting plate (60) can be maximized, so the amount of current moving between the first electrode terminal (200) and the first current collecting plate (60) can increase.

[0125] In addition, the height (D) of the first electrode terminal (200) can be further reduced compared to the conventional one. For example, in the case of a form factor 4680 battery cell, when the axial height of the conventional electrode terminal is about 1.2 cm, in the present invention, the thickness of the current collecting surface (210) can be reduced, in particular, to reduce the height (D) of the first electrode terminal (200) to 0.9 cm. Even if the thickness of the current collecting surface (210) is reduced, sufficient sealing performance can be secured because the current collecting surface (210) is wide. Then, even if the cell has the same external shape, the vertical height of the electrode assembly (50) can be increased, so that the energy density of the battery cell (10) can be improved.

[0126] In Fig. 3, the second hole sealing portion (240) may be a molten metal solidification portion (250). In one embodiment, the molten metal solidification portion (250) is a portion of the first electrode terminal (200) around the second hole (H') that has been melted and then solidified. The melting may be caused by locally irradiating a laser or by using friction stir welding.

[0127] Preferably, a molten metal solidification portion (250) can be formed by irradiating a laser in a manner similar to laser welding. The molten metal solidification portion (250) may be a weld bead. The weld bead is formed through laser welding. The weld bead refers to the deposited metal created by one welding (one laser beam pass) and may also be called a weld spot. The size, shape, position, and degree of overlap of the weld bead may vary depending on the welding conditions. Welding methods using a laser beam may include wobble welding, spot welding, weaving (hatching) welding, and scan welding. If the size of the second hole (H') is very small, the second hole (H') can be filled even with one spot welding. The depth of the weld bead can be controlled by adjusting the laser welding intensity. The weld bead may be formed only partially near the surface of the second hole (H'), or may be formed to fill the entire second hole (H') up to the part where it expands into the first hole (H).

[0128] The terminal surface (230) can form a flat portion. The surface of the terminal surface (230) and the second hole sealing portion (240) can function as a positive terminal of the battery cell (10). Therefore, it is preferable that the terminal surface (230) be formed flat. If the second hole sealing portion (240) is formed using a welding bead, it is possible that it will not have a uniformly flat shape. Therefore, in some cases, after forming the second hole sealing portion (240), a work to flatten the surfaces of the terminal surface (230) and the second hole sealing portion (240) may be required. In conclusion, the surfaces of the terminal surface (230) and the second hole sealing portion (240) can form a flat portion that is parallel to the bottom portion (120) of the can (100). Here, “parallel” means substantially parallel when observed with the naked eye. “Flat” refers to something that is flat.

[0129] Since the first hole (H) is formed in the first electrode terminal preform (200'), the electrolyte can be injected through the first hole (H), and there is no need to provide an injection port in the lead (300). The first hole (H) can be reduced in size to be smaller than the first hole (H) through deformation of the first electrode terminal preform (200') while the first electrode terminal preform (200') is being plastically processed, that is, while the outer flange portion (232) is being formed, so that only the second hole (H') remains. Thereafter, a laser can be irradiated around the second hole (H') to locally melt the portion of the first electrode terminal around the second hole (H'), and after a cooling process, the molten metal solidifies, so that the second hole (H') is filled, and only the molten metal solidification portion (250) remains.

[0130] Accordingly, a battery cell (10) can be manufactured by injecting and sealing the first electrode terminal (200) without the need to provide a liquid inlet in the lead and seal it with a separate sealing part as in the past. According to one embodiment of the present invention, the process of assembling the electrode terminal and the process of sealing the liquid inlet, which had to be performed as separate processes in the past, are integrated.

[0131] As another example, the molten metal solidification portion (250) may be made by melting a filler of the same material as the first electrode terminal (200) material onto the first hole (H). In this case, there is an advantage in that it is easy to secure flatness between the surface of the molten metal solidification portion (250) and the surface of the external flange portion (232).

[0132] As another example, the molten metal solidification portion (250) may be made by melting a soldering material. The soldering material can fill the second hole (H') left by deformation of the first electrode terminal preform (200') and ensure flatness of the surface of the molten metal solidification portion (250) and the surface of the external flange portion (232).

[0133] Fig. 6 is a modified example of Fig. 3.

[0134] In another embodiment, a cap (260) may be further included that is coupled with the outer flange portion (232) to block the first hole (H). The cap (260) constitutes the second hole sealing portion (240). In other words, the second hole sealing portion (240) shown in FIG. 3 may be the cap (260) of FIG. 6 that is coupled with the outer flange portion (232) to block the first hole (H).

[0135] At this time, the cap (260) may include a substrate portion (262) that comes into contact with the axial surface of the outer flange portion (232), and an alignment protrusion (264) that extends axially inward from the substrate portion (262) and is inserted into the second hole (H').

[0136] The cap (260) can be joined to the outer flange portion (232). For example, the edge of the substrate portion (262) can be laser welded to the outer flange portion (232).

[0137] Although it is desirable to avoid using a separate sealing part if possible, a cap (260) including a substrate portion (262) having a flat surface may be used to ensure the flatness of the terminal surface (230).

[0138] Fig. 7 is a modified example of Fig. 6.

[0139] Here, the cap (260) is formed by bending the outer periphery of the substrate portion (262) downward to form a rib (266), and the rib (266) surrounds the edge of the outer flange portion (232) and is connected to the outer flange portion (232). The inner surface of the rib (266) and the outer surface of the outer flange portion (232) can be in close contact with each other.

[0140] Fig. 8 is another modified example of Fig. 3.

[0141] Here, the cap (260) is a block (270) embedded at the same height as the outer flange portion (232) inside the second hole (H'). The block (270) can be inserted into the second hole (H'). The outer diameter of the block (270) can be configured to be the same as the inner diameter of the second hole (H'). Alternatively, the outer diameter of the block (270) can be configured to be slightly larger than the inner diameter of the second hole (H'). In this case, the block (270) can be force-fitted into the inside of the second hole (H'). Therefore, the block (270) can be fixed at a certain position without moving up and down after being inserted into the second hole (H'). The outer circumference of the block (270) can be joined to the inner circumference of the second hole (H') by seam welding, but since the block (270) does not move in the winding axis direction even before being welded, smooth welding can be performed.

[0142] The block (270) may have a length extending from the second hole (H') to the first hole (H).

[0143] Referring again to FIG. 3, the terminal gasket (140) is interposed between the first electrode terminal (200) and the can (100), and may include an outer gasket (142), an inner gasket (144), and an intermediate gasket (146). The outer gasket (142), the inner gasket (144), and the intermediate gasket (146) may have different thicknesses depending on the location.

[0144] The outer gasket (142) is a portion interposed between the outer flange portion (232) and the outer surface of the bottom portion (120), the inner gasket (144) is a portion interposed between the inner flange portion (212) and the inner surface of the bottom portion (120), and the middle gasket (146) is a portion interposed between the pillar portion (220) and the through hole (130). The outer gasket (142) and the inner gasket (144) are divided based on the outer surface of the bottom portion (120) of the can (100). In the present invention, the thickness of the current collecting surface (210) can be reduced. Therefore, the current collecting surface (210) and the inner gasket (144) can be prevented from interfering with other components.

[0145] The outer gasket (142) may be exposed at least partially to the outside of the outer flange portion (232) of the first electrode terminal (200). The purpose of exposing the outer gasket (142) is to insulate the first electrode terminal (200) from the bottom portion (120) having the opposite polarity to the first electrode terminal (200). For electrical insulation between the first electrode terminal (200) and the bottom portion (120), the exposure width of the outer gasket (142) may be 0.1 mm to 1 mm. If the exposure width is less than 0.1 mm, the electrical insulation between the first electrode terminal (200) and the bottom portion (120) may be destroyed on a plane when a high c-rate charge / discharge of 300 A or more is performed. In addition, if the exposure width is greater than 1 mm, the electrical insulation effect is not further increased, but rather the area of ​​the bottom part (120) used as the cathode area is reduced, thereby reducing the contact area of ​​the component used for connection (e.g., bus bar).

[0146] As shown in Fig. 3, the inner gasket (144) and the intermediate gasket (146) can be formed as an integral part to form the first gasket (150a). Therefore, the terminal gasket (140) can include a first gasket (150a) interposed between the inner flange portion (212) and the can (100) in the radial direction and between the pillar portion (220) and the inner circumferential surface of the can (100) defining the through hole (130) in the axial direction, and a second gasket (150b) interposed between the outer flange portion (232) and the can (100) in the radial direction, and being an outer gasket (142) formed separately from the first gasket (150a).

[0147] The first gasket (150a) can be pressed against the bottom (120) of the can (100) from the inside of the can (100) while being inserted into the first electrode terminal preform (200'). After the injection is completed and before the spinning process is performed, the second gasket (150b) can be fitted to the pillar part (220) from the outside of the can (100), and while the pillar part (220) is plastically processed by the spinning process to form a terminal surface (230), the second gasket (150b) can be pressed against the bottom (120) of the can (100).

[0148] The terminal gasket (140) may be made of an insulating and elastic polymer resin. In one example, the terminal gasket (140) may be made of polypropylene, polybutylene terephthalate, polyfluoroethylene, or the like, but the present invention is not limited thereto.

[0149] Fig. 9 is another modified example of Fig. 3.

[0150] Here, the outer gasket (142) and the intermediate gasket (146) are integral. Accordingly, the terminal gasket (140) may include a third gasket (150c) interposed between the outer flange portion (232) and the can (100) in the radial direction and between the pillar portion (220) and the inner circumferential surface of the can (100) defining the through hole (130) in the axial direction, and a fourth gasket (150d) which is an inner gasket (144) interposed between the inner flange portion (212) and the can (100) in the radial direction and which is formed separately from the third gasket (150c).

[0151] As another example, the inner gasket (144), the middle gasket (146), and the outer gasket (142) of FIG. 3 may be integral.

[0152] Figure 10 is an enlarged view of part B of Figure 2, showing part B of Figure 2 flipped upside down.

[0153] The lid (300) has a disc shape so as to block the open end of the can (100), and may be finished by joining the side wall (110) of the can (100) and the edge of the lid (300).

[0154] The lead (300) can be pressed through the open end of the can (100). The lead (300) can be configured to be finished by joining the side wall (110) of the can (100) and the edge of the lead (300) so that the can (100) and the lead (300) are electrically connected while the electrode assembly (50) is accommodated inside the can (100). The joining can be accomplished by welding, brazing, or soldering.

[0155] The lid (300) may be laser welded to the can (100) to include a weld (302) on the surface where the lid (300) and the can (100) meet. The welding may be performed by a laser irradiated inwardly in the axial direction.

[0156] A second collector plate (70) can be joined to the second non-conductive portion (54) and electrically connected. The second collector plate (70) has a joining surface (72) that is connected to the second non-conductive portion (54), and welding can be performed on this joining surface (72). The edge of the second collector plate (70) can be laser-welded to the can (100) to form a welding portion (74) on the surface where the second collector plate (70) and the can (100) are in contact. As the second non-conductive portion (54), the second collector plate (70), and the can (100) are connected, and as the can (100) and the lead (300) are connected, the lead (300) can be electrically connected to the second non-conductive portion (54).

[0157] In the manufacturing process, the weld (74) is formed first and then the weld (302) is formed. Since the weld (74) is formed first and the welding quality is confirmed before the weld (302) is formed, the occurrence of defects is reduced.

[0158] Fig. 11 is a modified example of Fig. 10. Fig. 12 is a partial cutaway perspective view showing an example of another lead.

[0159] Comparing Figs. 11 and 12 first, the lead (300) of Fig. 12 is directly connected to the second non-conductive part (54) without the second collector plate (70) of Fig. 11.

[0160] In Fig. 11, the lead (300) may sequentially include, from the radially outer side to the inner side, a mating surface (312), a curved surface (314), an inclined surface (316), and a support surface (318). In Fig. 12, the lead (300) may further include an electrode connection portion (320) connected to the support surface (318).

[0161] The mating surface (312), the curved surface (314), and the inclined surface (316) can form a U-shaped bend. The mating surface (312) is provided on the radially outer edge of the lead (300) and extends axially so that its outer surface contacts the inner surface of the side wall portion (110). The curved surface (314) is connected to the lower end of the mating surface (312) of the lead (300), that is, the axially inner end of the mating surface (312), and has a downwardly convex cross-sectional shape that extends radially inwardly as it goes axially inward. The slope of the curved surface (314) gradually becomes gentler as it gets farther from the mating surface (312). Since the mating surfaces (312) extend parallel to the axial direction, the slope of the tangent line of the outer surface of the curved surface (314) can gradually decrease from 90 degrees as it gets farther from the mating surface (312).

[0162] The inclined surface (316) continues from the curved surface (314). The inclined surface (316) extends radially inward and axially outward, but its slope may be constant.

[0163] A lid (300) having a U-shaped bend is suitable for being pressed through the open end of the can (100). The curved surface (314) and the inclined surface (316) provide a cross-sectional shape that allows the lid (300) to be elastically deformed radially inward. Accordingly, when the lid (300) is pressed into the open end, the U-shaped bend is compressed and then spread so that the lid (300) can be fitted into the open end while minimizing deformation of other parts. Accordingly, a radial sealing force can be secured between the side wall portion (110) of the can (100) and the abutment surface (312). In other words, the abutment surface (312) can be strongly abutted against each other without being distorted during the process of pressing the lid (300) into the open end of the can (100).

[0164] A support surface (318) extending radially horizontally may be provided radially inwardly from the curved surface (314) of the lead (300). The support surface (318) may be connected to a radially inner end of the inclined surface (316) and may extend horizontally radially inwardly from the connection portion. The support surface (318) provides a flat surface between the inclined surface (316) and the electrode connection portion (320). Accordingly, the surface of the support surface (318) may have a flat ring shape, and may serve as a foot of the battery cell (10) when the battery cell (10) is erected so that the lead (300) is placed on the floor.

[0165] The axial outer surface of the support surface (318) may be positioned axially further outward than the axial outer end of the mating surface (312). That is, the height of the axial outer surface of the support surface (318) may be positioned higher than the height of the axial outer end of the mating surface (312). Accordingly, when the battery cell (10) is placed on the floor, the weld (302) between the mating surface (312) and the side wall portion (110) is not directly subjected to a load, so that the weld (302) can be protected.

[0166] In Fig. 11, the shape of the second collector plate (70) is different from the shape of the second collector plate (70) of Fig. 10. In addition, in Fig. 11, the curved surface (314) of the lead (300) is in contact with the second collector plate (70).

[0167] In Fig. 12, an electrode connection portion (320) extending horizontally in the radial direction is provided radially inward from the support surface (318) of the lead (300). The electrode connection portion (320) is connected to the radial inward side of the support surface (318) and may be recessed into the inside of the can (100). The electrode connection portion (320) may be provided by plastic processing such that a predetermined portion of the lead (300) in the form of a metal sheet is recessed axially inward.

[0168] When the lead (300) is pressed into the can (100), the lead (300) can be pressed to a position where the bottom surface (axial inner surface) of the electrode connection portion (320) is in close contact with the second uncoated portion (54) of the electrode assembly (50) accommodated inside the can (100). The electrode connection portion (320) and the second uncoated portion (54) can be joined by welding. The welding can be performed by a laser irradiating the axial outer surface of the electrode connection portion (320) from the axial outer side. The laser can be irradiated in a scan manner along the radial direction to form a weld that extends long in the radial direction. In this way, the lead (300) functions as a cover that closes the open end of the can (100) while also functioning as a second current collector (70).

[0169] The joint portion of the electrode connection portion (320) and the second non-conductive portion (54) may extend radially. The electrode connection portion (320) may be arranged radially inward relative to the support surface (318). The electrode connection portion (320) may have a shape that is axially recessed relative to the support surface (318). A second inclined surface (322) may be provided between the electrode connection portion (320) and the support surface (318) in the radial direction, which extends axially inward as it goes radially inward, but has a substantially constant inclination. The second inclined surface (322) may extend axially inward as it goes radially inward, but has a substantially constant inclination. The inclination of the inclined surface (316) may be smaller than that of the second inclined surface (322). That is, the second inclined surface (322) may be steeper than the inclined surface (316). Accordingly, the radial length of the support surface (318) and the electrode connection portion (320) can be secured to the maximum extent.

[0170] The electrode connection portion (320) may extend radially outwardly by at least 0.5 times the radius of the can (100). Accordingly, a sufficient radial joint length between the electrode connection portion (320) and the second non-coated portion (54) may be secured. Preferably, the electrode connection portion (320) may extend radially outwardly by at least 0.7 times the radius of the can (100). The electrode connection portion (320) may provide a bottom surface that extends flatly in the radial direction. The height of the bottom surface of the electrode connection portion (320) may be lower than the height of the lower end of the curved surface (314). That is, the electrode connection portion (320) may protrude further axially inwardly than the curved surface (314). Then, the lower part of the curved surface (314) can be spaced apart in the axial direction from the electrode assembly (50) accommodated inside the can (100), while the lower surface of the electrode connection portion (320) can be brought into close contact with the second non-coated portion (54) of the electrode assembly (50). Accordingly, the bonding process between the electrode connection portion (320) and the second non-coated portion (54) can be smoothly performed.

[0171] When the above-described lead (300) is applied, the joint portion between the lead (300) and the can (100) is simple, and there is no need to use a current collector plate when electrically connecting the second non-conductive portion (54) to the can (100), thereby reducing the number of parts and assembly work, securing more internal volume, and increasing energy density.

[0172] In the examples illustrated in FIGS. 10 to 12, a vent (V) is provided in the lead (300). The vent (V) may be defined by a thin wall portion. Since the vent (V) is provided in the lead (300) and does not occupy a separate space, energy density can be further secured.

[0173] The vent (V) can rupture when the pressure inside the can (100) exceeds a critical value. The vent (V) can be formed on one or both sides of the lid (300). The vent (V) can form a continuous or discontinuous circular pattern, a linear pattern, or any other pattern on the surface of the lid (300). For example, the vent (V) can be formed in the shape of a roughly circular ring having a certain width. Such a circular ring-shaped vent (V) can have a center congruent with the center of the lid (300).

[0174] Referring to Fig. 12, the vent (V) may be provided radially outside the electrode connection portion (320). Here, it is exemplified that it is provided on the support surface (318). Preferably, the vent (V) may be implemented as a thin-walled portion having both surfaces of the support surface (318) notched. The strength of the vent (V) is such that it does not deform under the force applied when the lid (300) is pressed into the can (100), and when the internal pressure surges due to a short circuit occurring inside the can (100), it may be broken, thereby separating the electrode connection portion (320) of the lid (300) and the mating surface (312) of the lid (300). Accordingly, the electrical connection between the electrode connection portion (320) connected to the second non-conductive portion (54) and the can (100) is severed, and the internal space of the can (100) is opened to the outside, thereby discharging the gas that caused the internal pressure.

[0175] Meanwhile, the vent (V) may be provided concentrically with the first electrode terminal (200) on the bottom (120) of the can (100). This vent (V) is broken when the internal pressure surges due to a short circuit occurring inside the can (100), thereby rupturing the bottom (120) of the can (100) and opening the internal space of the can (100) to the outside, thereby releasing the gas that caused the internal pressure.

[0176] The breaking pressure of the can (100) can be controlled by controlling the depth and width of the vent (V). For example, the vent (V) can be configured to control the pressure inside the can (100) to be 15 to 35 kgf / cm 2It can be set to be ruptured when it is in the range of . The vent (V) can be formed by notching to partially reduce the thickness of the can (100). The vent (V) can have a thickness gradient. The thickness gradient means that when checking the cross-section of the vent (V), it is formed by being inclined at a certain angle with respect to a predetermined horizontal plane. Such a vent (V) is ruptured when the pressure inside the can (100) abnormally increases, thereby releasing all the gas inside to the outside.

[0177] FIG. 13 is a drawing for explaining a battery pack according to one embodiment of the present invention. FIG. 14 is a drawing for explaining a vehicle including the battery pack of FIG. 13.

[0178] Referring to FIG. 14, a battery pack (500) 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 (500) according to the present invention may include a pack housing (510) capable of accommodating the at least one battery cell (10). The battery pack (500) 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 is no particular difficulty in implementing the battery pack (500) even without using an intermediate structure called a battery module.

[0179] In addition, the battery pack (500) may further include various other components in addition to the battery cells (10), such as components of the battery pack (3) known at the time of application of the present invention, such as a BMS, a pack case, a relay, a current sensor, etc.

[0180] A battery pack (500) may include a plurality of battery cells (10). The battery cells (10) may be arranged in a predetermined number of rows, and may be arranged such that both the first electrode terminal (200) and the second electrode terminal (290) of each battery cell (10) are positioned on the upper side. Therefore, when electrically connecting the plurality of battery cells (10), both the positive and negative poles can be connected in one direction, thereby simplifying the electrical connection structure. This increases the number of battery cells (10) that can be mounted in the same space, thereby improving energy density and facilitating electrical wiring work. Therefore, the space efficiency is good, and the electrical wiring efficiency is high, which significantly improves workability during the assembly process of the electric vehicle and the assembly and maintenance of the battery pack (500). In addition, as described above, each battery cell (10) may have a higher energy density than before. A battery pack (500) with increased energy density in this way can store the same amount of energy while reducing its volume and load.

[0181] Therefore, if a battery pack (500) to which such a battery cell (10) is applied is mounted on a vehicle such as an automobile (600) that uses electricity as an energy source as shown in FIG. 14, the mileage of the vehicle can be further increased in proportion to the energy consumed.

[0182] In addition, since the electrical wiring is performed on the side where the bottom (120) of the can (100) and the first electrode terminal (200) are located, and the electrical wiring may not be placed on the lead (300) located on the opposite side, the effect of the vent (V) formed on the lead (300) can be maximized. In addition, if a heat sink, cooling plate, tray, etc. are positioned on the side of the lead (300), the purpose of assembly and cooling, etc. can be effectively achieved regardless of the electrical wiring connection part. In addition, by assembling with the vent (V) facing downward, the gas emitted from inside the secondary battery is discharged downward. Since the secondary battery is usually mounted at a lower position than the passengers of a vehicle such as an EV, if the gas is discharged upward from the secondary battery, it may cause harm to the passengers. The battery cell (10) of the present invention not only effectively discharges high-pressure gas inside the secondary battery, but is also safe because it is independent of the upper electrical wiring connection part, and further, when the gas is discharged due to a vent (V) break, it is discharged downwards and does not cause harm to the passengers, thereby greatly improving safety.

[0183] Referring to FIG. 14, a vehicle (600) according to the present invention may include at least one battery pack (500) according to the present invention.

[0184] The battery cell (10) according to the present invention can be applied to automobiles such as electric vehicles or hybrid vehicles. That is, the automobile (600) according to the present invention can include the battery cell (10) according to the present invention or the battery pack (500) according to the present invention. In addition to the battery cell (10) or the battery pack (500), the automobile (600) according to the present invention can further include various other components included in the automobile. For example, the automobile (600) according to the present invention can further include a body, a motor, a control device such as an electronic control unit (ECU), etc., in addition to the battery cell (10) according to the present invention. The automobile (600) includes a four-wheeled automobile and a two-wheeled automobile. The automobile (600) can operate by receiving power from the battery pack (500) according to one embodiment of the present invention.

[0185] 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.

[0186] [Explanation of symbols]

[0187] 10: Battery cell 50: Electrode assembly

[0188] 100: Can 110: Side wall

[0189] 120: Bottom 130: Through hole

[0190] 140: Terminal gasket 142: Outer gasket

[0191] 144: Inner gasket 146: Middle gasket

[0192] 200: First electrode terminal 210: Current collector surface

[0193] 212: Inner flange part 220: Column part

[0194] 230: Terminal surface 232: External flange

[0195] 240: Second hole sealing section 250: Molten metal solidification section

[0196] 260: Cap 262: Board

[0197] 264: Alignment protrusion 266: Rib

[0198] 270: Block 290: Second electrode terminal

[0199] 300: Lead 500: Battery Pack

[0200] 600: Car H: Hole 1

[0201] H': 2nd hole V: Vent

Claims

1. Electrode assembly; a can accommodating the electrode assembly; and including a first electrode terminal electrically connected to the electrode assembly; The first electrode terminal includes a current collecting surface located on the inside of the can, a pillar portion extending from the current collecting surface and penetrating the can, and a terminal surface extending from the pillar portion and located on the outside of the can. A first hole is formed through the above-mentioned column portion and passes through the above-mentioned collector surface, A second hole is formed on the terminal surface, which is connected to the first hole and is smaller than the first hole. A battery cell characterized in that the second hole is sealed on the surface of the terminal surface.

2. A battery cell characterized in that, in the first paragraph, the can includes a side wall portion, a bottom portion connected to one axial end of the side wall portion, an open end provided at the other axial end of the side wall portion, and a lead covering the open end.

3. In the second paragraph, the electrode assembly is a battery cell characterized in that the first electrode and the second electrode are wound with a separator interposed therebetween, and the electrode assembly is accommodated inside the can so that the non-conductive portion of the second electrode faces the open end.

4. In paragraph 3, A battery cell characterized in that a through hole is formed in the bottom portion, and the first electrode terminal penetrates the through hole and is electrically connected to the first electrode.

5. In the fourth paragraph, the battery cell further includes a first collector plate configured to be electrically connected to the first electrode, at least a portion of the first collector plate is coupled to the inner surface of the first electrode terminal, and a battery cell characterized in that a hole is formed in the center of the first collector plate and is aligned with the first hole.

6. In the second paragraph, the battery cell is characterized in that the current collector surface forms an inner flange portion extending from the first side of the pillar portion along the inner surface of the bottom portion, and the terminal surface forms an outer flange portion extending from the second side of the pillar portion along the outer surface of the bottom portion.

7. A battery cell according to claim 6, characterized in that the inner surface of the inner flange portion is provided flat.

8. In paragraph 5, The above-mentioned collector surface forms an inner flange portion extending along the inner surface of the bottom portion from the first side of the column portion, A battery cell characterized in that the inner flange portion extends radially outward from the first side of the pillar portion disposed inside the can so as to extend radially outward more than the through hole, and is joined to the first collector plate.

9. In paragraph 8, The terminal surface forms an external flange portion extending along the outer surface of the bottom portion from the second side of the pillar portion, A battery cell characterized in that the outer flange portion is a plastically processed portion formed by plastically processing a second side protruding from the pillar portion to the outside of the can to extend radially outwardly more than the through hole in the radial direction.

10. In paragraph 1, A battery cell characterized in that the first electrode terminal is made of metal, and the terminal surface is formed by plastic processing of a portion of the pillar portion protruding outward from the can.

11. In paragraph 1, A battery cell characterized in that a second hole sealing portion is formed on the terminal surface.

12. A battery cell according to claim 11, characterized in that the second hole sealing portion is a molten metal solidification portion.

13. A battery cell according to claim 12, wherein the molten metal solidification portion is a portion of the first electrode terminal around the second hole that is melted and then solidified.

14. In paragraph 9, A battery cell characterized in that it further includes a cap that is coupled to the external flange portion and blocks the second hole.

15. A battery cell according to claim 14, wherein the cap comprises a substrate portion that contacts the axial surface of the outer flange portion; and an alignment protrusion that extends axially inward from the substrate portion and is inserted into the second hole.

16. A battery cell according to claim 1, further comprising a terminal gasket interposed between the first electrode terminal and the can.

17. In paragraph 16, The can includes a side wall portion, a bottom portion connected to one axial end of the side wall portion, and an open end provided at the other axial end of the side wall portion. A through hole is formed in the above bottom portion, and the first electrode terminal passes through the through hole. The above-mentioned collector surface forms an inner flange portion extending along the inner surface of the bottom portion from the first side of the column portion, and the above-mentioned terminal surface forms an outer flange portion extending along the outer surface of the bottom portion from the second side of the column portion. A battery cell characterized in that the terminal gasket includes an outer gasket interposed between the outer flange portion and the outer surface of the bottom portion, an inner gasket interposed between the inner flange portion and the inner surface of the bottom portion, and an intermediate gasket interposed between the pillar portion and the through hole.

18. In paragraph 2, A battery cell characterized in that the lead has a disc shape so as to block the open end of the can, and is finished by joining the side wall portion of the can and the edge of the lead.

19. A can preparation step of preparing a can having a side wall portion, a bottom portion connected to one axial end of the side wall portion, and an open end provided at the other axial end of the side wall portion, and assembling a first electrode terminal preform including a current collecting surface located inside the can and a pillar portion extending from the current collecting surface, penetrating the can, protruding outward from the can, and having a first hole formed through the current collecting surface at a central portion thereof, to the bottom portion; An electrode assembly receiving step for receiving the electrode assembly in the can; A lid assembly step of covering and closing the open end of the above can with a lid; A step of injecting an electrolyte into the can through the first hole; A step of forming a terminal surface extending from the pillar portion and positioned on the outside of the can by plastically processing the pillar portion protruding from the outside of the can; and A battery cell manufacturing method comprising a step of sealing the first hole on the surface of the terminal surface to complete a first electrode terminal.

20. In paragraph 19, the lead assembly step is: A step of covering the open end of the can with a lead; and A method for manufacturing a battery cell, characterized by comprising a step of joining the side wall portion of the can and the edge contact surface of the lead.

21. A battery cell manufacturing method characterized in that, in claim 19, the electrode assembly is electrically connected to the current collecting surface of the first electrode terminal preform and then the electrode assembly is accommodated in the can.

22. A battery pack comprising at least one battery cell according to any one of claims 1 to 18.

23. A vehicle comprising a battery pack according to Article 22.