Device for reforming separator of electrode assembly, electrode assembly insertion device including same, and method for reforming separator of electrode assembly

Abstract

Provided is device for reforming a separator, wherein the device can be used during the process of inserting an electrode assembly into a can. The reforming device comprises: a body part for supporting the bottom surface of the electrode assembly; a head part including a plurality of divided heads that are mounted on an upper portion of the body part so as to be able to reciprocate in a radial direction with respect to a central portion; a reforming pin that is connected to each of the divided heads from the center of the head part and extends upward in the axial direction from the divided heads so as to be inserted into a winding core cavity of the electrode assembly; an actuator for moving the divided heads outward in the radial direction; a return member for returning the divided heads inward in the radial direction; and a heating part for heating the reforming pin.

Description

A separator reforming device for an electrode assembly, an electrode assembly insertion device having the same, and a separator reforming method for an electrode assembly

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0080634, dated June 20, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a device for reforming a separator of a cylindrical electrode assembly, and more specifically, to a separator reforming device that can be used in the process of inserting an electrode assembly into a can.

[0003] With the proliferation of electric vehicles, the capacity of cylindrical battery cells, manufactured using cylindrical battery cans as housings, is increasing. Consequently, compared to conventional cylindrical battery cells, the diameter and height of the electrode assembly have increased, and the internal space of the can housing it has also expanded.

[0004] On the other hand, the diameter of the core cavity of the electrode assembly remains unchanged compared to the conventional case. In the conventional case, the volume of air present in the internal space of the can was small, so when the electrode assembly was inserted into the internal space of the can, the air present in the can was not discharged at a large flow rate through the core cavity of the electrode assembly.

[0005] However, compared to conventional battery cells, battery cells with increased capacity contain a larger volume of air within the can. Therefore, when inserting the electrode assembly into the can, the air within the can is discharged through the core cavity of the electrode assembly at a very high air velocity. Consequently, the core portion of the separator within the core cavity may become loose.

[0006] When the core portion of the separator is loosened, when a tool is inserted through the core cavity during a subsequent process, the tool deforms or damages the loose core portion of the separator. This causes a reduction in the capacity and lifespan of the battery cell.

[0007] The present invention has been derived to solve the above-described problem, and aims to provide a membrane reforming device capable of reforming a core portion of a membrane so that it is in close contact with an inner circumferential surface defining a core hollow portion of an electrode assembly.

[0008] The present invention aims to provide an electrode assembly insertion device capable of preventing a core portion of a separator from coming loose when inserting an electrode assembly of a cylindrical battery cell into a can.

[0009] The present invention aims to provide a method for reforming a separator of an electrode assembly, which can reform a core portion of a separator in a process of inserting the electrode assembly into a can.

[0010] 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.

[0011] The present invention, in order to solve the above-described problem, provides a membrane reforming device including a body part that supports the bottom surface of an electrode assembly, a head part having a plurality of dividing heads installed on the upper part of the body part so as to be able to reciprocate radially with respect to the center, and a reforming pin that is connected to each dividing head at the center of the head part and extends upward in the axial direction from the dividing head so as to be inserted into the core hollow portion of the electrode assembly.

[0012] The above-mentioned dividing head may be divided into multiple parts in a circumferential direction with respect to the center. Preferably, three of the above-mentioned dividing heads may be provided to correspond to a 120-degree section.

[0013] The outer periphery of the above reform pin may have a convex arc shape.

[0014] The upper portion of the above reform pin may be provided with an insertion guide surface in the form of a slope whose outer diameter gradually decreases toward the upper portion.

[0015] The above body portion may be provided with a first guide portion extending radially to guide the radial movement of each of the dividing heads. Preferably, the first guide portion may be a radially extending rail groove. Three first guide portions may be provided at 120-degree intervals in the circumferential direction.

[0016] Each of the above-described dividing heads may have a second guide portion that contacts the first guide portion and radially swivels. Preferably, the second guide portion may be a rail projection extending radially.

[0017] The above dividing head is movable to a basic position gathered at the center and to an extended position moved radially outward from the center.

[0018] The above membrane reforming device may further include an actuator that moves the dividing head radially outward. The actuator may be installed in the body portion so as to be able to move upward and downward in the axial direction.

[0019] A contact portion that comes into contact with the actuator may be provided on the radially inner side of the above-mentioned dividing head.

[0020] The above contact portion may be provided with an inner sloping surface whose inner diameter gradually decreases upward.

[0021] The upper portion of the above actuator is provided with an outer sloping surface whose outer diameter gradually decreases upward, and the slope of the outer sloping surface can correspond to the slope of the inner sloping surface.

[0022] The above membrane reforming device may further include a return member that returns the dividing head radially inward. The return member may be an elastic body that elastically supports the dividing head radially inward. The elastic body may be a coil spring embedded in the rail groove and extending in the longitudinal direction of the rail groove, i.e., in the radial direction of the body portion.

[0023] The above membrane reforming device may further include a heating unit that heats the reforming pin.

[0024] The heating unit may be placed on the upper surface of the body unit in contact with the head unit.

[0025] The above heating unit can heat the reform pin using a resistance heating method.

[0026] The above reform pin can be heated to 120 to 140 degrees Celsius by the heating unit.

[0027] The present invention provides an electrode assembly insertion device having the above-described membrane reforming device.

[0028] The above electrode assembly insertion device includes a can holder that supports the can so that the opening of the internal space of the can faces downward, and a lifter that inserts the electrode assembly axially upward through the opening from the lower portion of the can holder.

[0029] The above membrane reforming device is installed in the above lifter.

[0030] The present invention provides a method for reforming a separator portion provided in a core hollow portion of an electrode assembly using the electrode assembly insertion device.

[0031] The method includes a step of inserting the electrode assembly through the opening of the can to a first position in the internal space of the can using the lifter while inserting the reform pin of the dividing head arranged at the basic position into the core hollow portion of the electrode assembly.

[0032] The method includes a step of operating the actuator so that the splitting head moves radially outward from the first position to bring the separator portion of the core hollow portion into close contact with the inner circumference of the electrode assembly using the reform pin.

[0033] The above method may further include a step of hot reforming the separator portion that is in close contact with the inner circumference of the core hollow portion by heating the reform pin.

[0034] The method may further include a step of inserting the electrode assembly to a second position deeper than the first position using the lifter.

[0035] When the separator reforming device of the present invention is applied to an electrode assembly insertion device, the phenomenon of the core portion of the separator coming loose during the process of inserting the electrode assembly into a can can be prevented.

[0036] When the separator reforming device of the present invention is applied to an electrode assembly insertion device, a reforming process for bringing the core portion of the separator into close contact with the inner circumferential surface defining the core hollow portion of the electrode assembly can be performed simultaneously with the process of inserting the electrode assembly into the can. Therefore, a separate separator reforming process can be omitted.

[0037] According to the separator reforming method of the present invention, the core part of the separator can be reformed simultaneously while inserting the electrode assembly into the can.

[0038] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0039] Figure 1 is an exploded perspective view of an electrode assembly housed inside a can of a battery cell before winding.

[0040] Fig. 2 is a perspective view of the electrode assembly of Fig. 1 in a pre-winding laminated state.

[0041] Figure 3 is a perspective view of an assembled cylindrical jelly-roll-shaped electrode assembly by winding up the laminate of Figure 2.

[0042] Figure 4 is a perspective view showing a state in which a first collector plate is joined to an electrode tab provided at an axial first end of an electrode assembly facing the end wall of a can.

[0043] Figure 5 is a perspective view showing a state in which a second collector plate is joined to an electrode tab provided on an axial second end of an electrode assembly facing a second end wall or opening of a can.

[0044] Figure 6 is a cross-sectional lower perspective view of a can accommodating the electrode assembly of Figure 5.

[0045] Figure 7 is a perspective view of an electrode assembly insertion device according to the present invention.

[0046] Fig. 8 is an exploded upper perspective view of a membrane reforming device applied to the electrode assembly insertion device of Fig. 7.

[0047] Fig. 9 is an exploded lower perspective view of the membrane reforming device of Fig. 8.

[0048] Figure 10 is a cross-sectional view showing a can with an insulator inserted into a can holder in a state of being gripped.

[0049] Figure 11 is a cross-sectional view showing a state in which a reforming device having an electrode assembly is raised by a lifter.

[0050] Figure 12 is a cross-sectional view taken along line XII-XII of Figure 11.

[0051] Figure 13 is a cross-sectional view showing the electrode assembly inserted to the first position in the internal space of the can.

[0052] Figure 14 is a cross-sectional view showing a state in which the actuator of the reforming device rises and the dividing head moves radially outward accordingly, so that the reforming pin is in close contact with the core portion of the separator against the inner surface of the electrode assembly.

[0053] Fig. 15 is a cross-sectional view taken along line XV-XV of Fig. 14.

[0054] Figure 16 is a drawing showing a state in which the electrode assembly is inserted to the final position in the internal space of the can while the reform pin is reforming the core portion of the separator.

[0055] Fig. 17 is a cross-sectional view showing a state in which the actuator of the reforming device is lowered from the final position and the splitting head is moved radially inward by the return member, so that the reforming pin is spaced radially inward from the inner surface of the electrode assembly.

[0056] Fig. 18 is a cross-sectional view taken along line XVIII-XVIII of Fig. 17.

[0057] Figure 19 is a cross-sectional view showing the process of removing the separator reform pin from the core hollow portion of the electrode assembly while the electrode assembly is inserted to the final position and the reform pin is retracted.

[0058] Figure 20 is a cross-sectional view showing the process of welding the first collector plate and the first electrode terminal by inserting a welding rod through the core hollow portion of the electrode assembly after the insertion process of the electrode assembly is completed.

[0059] [Explanation of symbols]

[0060] 10: Can 11: Side wall 12: End wall 15: Cap gasket 17: First electrode terminal 170: Terminal gasket 19: Insulator 20: Electrode assembly 21: First electrode 22: Second electrode 23: Metal foil (current collector) 24: Active material layer (active material) 25: Supporting portion 26: Non-coated portion 27: Electrode tab (notched tab) 28: Separator 280: Core portion 29: Core hollow portion 30: First current collector 31: Peripheral portion 310: First electrode junction 32: Central portion 320: Terminal junction 33: Bridge 40: Second current collector 41: Center portion 410: Second electrode junction 42: Rim portion 43: Connection portion 50: Can holder 60: Lifter 70: reforming device 71: body part 711: first guide part (rail groove) 72: head part 722: split head 723: contact part (inner slanted surface) 724: reforming pin 725: insertion guide surface 727: second guide part (rail protrusion) 74: actuator 746: outer slanted surface 75: heating part 76: return member (elastic body, coil spring) 90: electrode assembly insertion device

[0061] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0062] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0063] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0064] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0065] Additionally, when it is described that a component is "connected," "coupled," or "contacted" with another component, it should be understood that the components may be directly connected or in contact with each other, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "contacted" through another component.

[0066] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0067] Throughout the specification, when we refer to "A and / or B", this means A, B, or A and B, unless otherwise stated, and when we refer to "C to D", this means C or more and D or less, unless otherwise stated.

[0068] In describing the embodiment, the axial direction refers to the direction in which the axis forming the winding center of the jelly-roll type electrode assembly extends, the radial direction (radial direction) refers to the direction closer to or farther from the axis, and the circumferential direction (circumferential direction) refers to the direction surrounding the axis.

[0069] Hereinafter, with reference to FIGS. 1 to 6, the structure of an electrode assembly and a can to which the membrane reforming device and the electrode assembly insertion device of an embodiment of the present invention can be applied will be described. However, the structure of the electrode assembly and the can described below is merely one embodiment, and it is obvious that the membrane reforming device and the electrode assembly insertion device of the embodiment can also be applied to electrode assemblies and cans having different structures.

[0070] Referring to FIGS. 1 to 3, the electrode assembly (20) is prepared by preparing a first electrode (21), a second electrode (22), and a separator (28) that extend in the longitudinal direction with a predetermined width (see FIG. 1), and then stacking them in the order of the first electrode (21), the separator (28), the second electrode (22), and the separator (28) as shown in FIG. 2, and manufacturing them in the form of a jelly-roll wound around a core shaft (see FIG. 3).

[0071] The above first electrode (21) may be an anode, and the above second electrode (22) may be a cathode. Of course, the opposite may also be the case.

[0072] The first electrode (21) and the second electrode (22) are manufactured in the form of sheets that extend in the longitudinal direction with a predetermined width. The electrode sheet is manufactured in the form in which an active material (24) is applied to the surface of a current collector (23) such as a metal foil. The current collector has a holding portion (25) region where the active material (24) is applied, and a non-conductive portion (26) region where the active material (24) is not applied. The current collector (23) of the first electrode (21) has a non-conductive portion (26) region at a first end in the width direction, and the current collector (23) of the second electrode (22) has a non-conductive portion (26) region at a second end in the width direction.

[0073] The non-conductive portion (26) region of the current collector (23) of the first electrode (21) and the second electrode (22) is exposed or protrudes from the laminated body as the first end and the second end in the width direction, respectively, as shown in Fig. 2. The non-conductive portion (26) itself functions as an electrode tab (27).

[0074] In the above-mentioned blank portion (26), notches can be formed at a predetermined interval to form flag-shaped electrode tabs (27).

[0075] In the embodiment, the electrode tabs (27) are exemplified as having an equilateral trapezoidal shape. However, their shapes may be various, such as a semicircle, a semi-ellipse, a triangle, a rectangle, or a parallelogram.

[0076] In addition, in the embodiment, a form in which the electrode tabs (27) arranged along the longitudinal direction have the same width is exemplified. However, the width of the electrode tabs may be gradually or stepwise widened from the core side to the outer periphery side.

[0077] In addition, in the embodiment, a form in which the height of the electrode tabs (27) gradually increases from the core side to the outer circumference side is exemplified. However, the height of these electrode tabs may be implemented in a form in which they are constant or gradually decrease.

[0078] In addition, in the embodiment, a structure is exemplified in which the electrode tab (27) is deleted in a predetermined section of the centripetal end of the non-conductive portion (26) and a predetermined section of the centrifugal end. However, it is of course possible that the electrode tab may not be deleted in the centripetal end of the non-conductive portion, or that the electrode tab may not be deleted in the centrifugal end of the non-conductive portion, or that neither may be deleted.

[0079] In the jelly roll-shaped electrode assembly (20), the electrode tab (27) can be bent radially and flattened as shown in Fig. 6. The electrode tab (27) can be bent radially inward or outward. Preferably, the electrode tab (27) can be bent radially inward.

[0080] The above electrode tabs (27) can be bent one by one during the process of forming a jelly roll-shaped electrode assembly (20) by winding the laminate. Alternatively, the electrode tabs (27) can be bent all at once after the laminate is wound to form a jelly roll-shaped electrode assembly.

[0081] The electrode tabs (27) of the first electrode (21) and the electrode tabs (27) of the second electrode (22), which are bent and overlapped in the radial direction in this way, can provide a first plane and a second plane that are substantially perpendicular to the axial direction at the axial ends of the electrode assembly (20), respectively.

[0082] The electrode tabs (27) exposed at both axial ends of the electrode assembly (20) are bent to provide substantially flat first and second surfaces, and a first collector plate (30) and a second collector plate (40) can be joined to each other as shown in FIGS. 4 and 5.

[0083] In the embodiment, the first collector plate (30) is exemplified as a positive collector plate and the second collector plate (40) is a negative collector plate. However, the first collector plate (30) may be a negative collector plate and the second collector plate (40) may be a positive collector plate.

[0084] The second collector plate (40) may include a copper material, and the first collector plate (30) may include an aluminum material. However, the materials are not limited thereto.

[0085] The above-mentioned collector plate (30, 40) can be manufactured by punching, trimming, piercing, drawing or bending a metal plate or metal sheet.

[0086] Referring to Fig. 4, the first collector plate (30) includes a central portion (32) provided at a location corresponding to the core hollow portion (29) of the electrode assembly (20), and a peripheral portion (31) provided around the central portion (32). The central portion (32) is positioned at the center of the first collector plate (30) and is provided in a form that covers at least a portion of the core hollow portion (29) of the electrode assembly (20) in the axial direction. The peripheral portion (31) is spaced apart from the central portion (32) in the radial direction and surrounds the central portion (32).

[0087] The central portion (32) and the peripheral portion (31) are physically and electrically connected to each other through a bridge (33). The bridge (33) is disposed radially between the central portion (32) and the peripheral portion (31). The bridge (33) has a predetermined width in the circumferential direction and extends radially by a predetermined length. A first longitudinal end of the bridge (33) provided on the radially outer side is connected to the peripheral portion (31), and a second longitudinal end of the bridge (33) provided on the radially inner side is connected to the central portion (32). A plurality of bridges (33) are provided, and the plurality of bridges (33) are spaced apart from each other along the circumferential direction. Preferably, the plurality of bridges (33) may extend radially from a terminal connection portion (320) provided on the central portion (32) and be spaced apart from each other at equal intervals in the circumferential direction. The above peripheral portion (31) and central portion (32) are electrically connected to each other by the bridge (33).

[0088] The first plane provided by the electrode tabs (27) of the first electrode (21) bent radially inward faces the circumference (31) in the axial direction.

[0089] The first current collector plate (30) is electrically connected to the first electrode (21) of the electrode assembly (20) by being joined to the electrode tabs (27) of the first electrode (21) at the first electrode joints (310) provided on at least a portion of the circumferential portion (31). The first electrode joints (310) may be portions that are penetratedly welded to the electrode tabs (27) by a laser irradiated onto the surface of the first current collector plate (30). Each first electrode joint (310) extends in the radial direction, and a plurality of first electrode joints (310) are spaced apart from each other along the circumferential direction of the circumferential portion (31).

[0090] In the central portion (32) of the first collector plate (30), a terminal connection portion (320) is provided that faces the first electrode terminal (17) in the axial direction and is connected to the first electrode terminal (17).

[0091] Referring to Fig. 5, the second collector plate (40) includes a ring-shaped center portion (41) having a hole formed in the center, and a rim portion (42) surrounding the center portion (41) on the radially outer side of the center portion (41). The center portion (41) and the rim portion (42) are spaced apart from each other in the radial direction. The center portion (41) and the rim portion (42) are physically and electrically connected to each other through a plurality of connecting portions (43) extending radially with respect to the central axis.

[0092] In the above center portion (41), a plurality of second electrode joints (410) are provided that are penetratedly welded to the electrode tabs (27) of the second electrode (22) of the electrode assembly (20) by radially extending laser welding lines. The plurality of second electrode joints (410) are spaced apart from each other along the circumferential direction, avoiding the connection portion (43).

[0093] The above-mentioned edge portion (42) is joined to the side wall (11) of the can (10) and is electrically connected to the can (10).

[0094] Referring to FIG. 6, the can (10) has an internal space that accommodates the electrode assembly (20).

[0095] The can (10) includes a side wall (11) extending along an axial direction and surrounding an internal space in a circumferential direction, an end wall (12) connected to a first end of the side wall in the axial direction and extending radially to cover the internal space, and an opening provided at a second end of the side wall in the axial direction opposite to the first end in the axial direction.

[0096] The first electrode terminal (17), which is electrically connected to the first electrode (21) of the electrode assembly (20), is installed through the end wall (12) so as to be electrically insulated from the end wall (12). The first electrode terminal (17) is installed in the central portion of the end wall (12).

[0097] Between the above-mentioned end wall (12) and the first electrode terminal (17), a terminal gasket (170) having electrical insulation and high sealing properties is press-fitted.

[0098] The above end wall (12) may be connected to the side wall (11) before inserting the electrode assembly (20) into the internal space of the can (10).

[0099] The above end wall (12) may be manufactured as a separate part from the side wall (11) and then connected to the axial first end of the side wall (11), or may be formed integrally with the side wall (11) from the beginning and connected in a monolithic manner.

[0100] Referring to FIG. 7, an electrode assembly insertion device (90) according to an embodiment of the present invention includes a can holder (50) that supports a can (10) so that an opening in the internal space of the can (10) faces downward, and a lifter (60) that inserts an electrode assembly into the internal space of the can (10) axially upward through the opening from the lower portion of the can holder (50). The electrode assembly can be installed on the lifter (60) through the separator reforming device (70).

[0101] Referring to FIGS. 7 to 9, the membrane reforming device (70) includes a body part (71) that supports the bottom surface of the electrode assembly, and a head part (72) disposed on the upper portion of the body part (71). The head part (72) is provided with a plurality of dividing heads (722) that are installed on the upper portion of the body part (71) so as to be able to radially reciprocate with respect to the center of the body part (71). The dividing heads (722) may have a fan shape divided into a plurality of parts in the circumferential direction with respect to the center. In the embodiment, three dividing heads (722) are provided so as to correspond to a 120-degree section. In order to enable radial movement of the dividing heads (722), the radius of the fan shape of the dividing heads (722) is set smaller than the radius of the upper portion of the body part (71). The upper surface of the dividing heads (722) may also support the electrode assembly (20).

[0102] The above-mentioned dividing head (722) includes a reform pin (724) that is connected to each dividing head (722) at the center of the fan shape and extends upward in the axial direction from the dividing head (722) so as to be inserted into the core hollow portion of the electrode assembly. The outer circumference of the reform pin (724) has a convex arc-shaped profile corresponding to the inner circumference of the electrode assembly (20). An insertion guide surface (725) in the form of a sloped surface whose outer diameter gradually decreases toward the upper end is provided on the upper portion of the reform pin (724).

[0103] The above body portion (71) is provided with a plurality of first guide portions (711) extending radially to guide the radial movement of each of the dividing heads (722). In an embodiment, three first guide portions (711) are provided at 120-degree intervals in the circumferential direction. In one example, the first guide portions (711) may be rail grooves that are narrow at the top and wide at the bottom and extend radially.

[0104] Each of the above-described dividing heads (722) may be provided with a second guide portion (727) that radially swivels along the first guide portion (711). In one example, the second guide portion (727) may be a rail projection that is narrow at the top and wide at the bottom and extends radially. The rail projection is connected to the bottom surface of the above-described dividing head (722).

[0105] Accordingly, the above-mentioned dividing head (722) can be moved to a basic position gathered at the center of the body part (71), and can also be moved to an extended position moved radially outward from the center.

[0106] The above membrane reforming device (70) further includes an actuator (74) that moves the dividing head (722) radially outward. The actuator (74) is installed in the body portion (71) so as to be able to move upward and downward in the axial direction. The actuator (74) has a cylindrical shape extending in the axial direction, and an outer peripheral inclined surface (746) is provided on the upper portion thereof, the outer diameter of which gradually decreases as it goes upward.

[0107] A contact portion (723) that comes into contact with the actuator (74) is provided on the radially inner side of the above-mentioned dividing head (722). The above-mentioned contact portion (723) may be an inner slanted surface whose inner diameter gradually decreases as it goes upward. The slope of the outer slanted surface (746) of the above-mentioned actuator (74) and the slope of the inner slanted surface (723) may correspond to each other. Accordingly, when the above-mentioned actuator (74) rises from the body portion (71), the above-mentioned dividing head (722) moves radially outward.

[0108] The above membrane reforming device (70) includes a return member (76) that returns the dividing head (722) radially inward. In one example, the return member (76) is an elastic body that elastically supports the dividing head (722) radially inward, and may be a coil spring that is built into the rail groove (711) and extends in the longitudinal direction of the rail groove (711), i.e., in the radial direction of the body portion (71).

[0109] The above membrane reforming device (70) further includes a heating unit (75) for heating the reforming pin (724). The heating unit (75) is installed embedded in the upper surface of the body unit (71) that is in contact with the head unit (72). The heating unit (75) can heat the reforming pin (724) by a resistance heating method. The reforming pin (724) can be heated to 120 to 140 degrees Celsius by the heating unit (75). In one example, the reforming pin (724) is heated to approximately 130 degrees Celsius.

[0110] Referring to FIGS. 10 to 19 below, a method of reforming a membrane portion, i.e., a membrane core portion, provided in a core cavity (29) of an electrode assembly (20) while inserting the electrode assembly (20) into a can (10) using an electrode assembly insertion device (90) equipped with the membrane reforming device (70) will be described.

[0111] Referring to FIG. 10, the can (10) is held by the can holder (50) in a position such that the opening of the can (10) faces downward. When held by the can holder (50), the opening of the can (10) faces downward and opens the internal space of the can (10). As illustrated, an insulator (19) is mounted on the inner surface of the end wall (12) of the can (10). The insulator (19) exposes the first electrode terminal (17) downward, but does not substantially expose the end wall (12) downward.

[0112] Referring to Fig. 11, the reform pin (724) of the dividing head (722) arranged at the basic position is inserted into the core hollow portion (29) of the electrode assembly (20), and the electrode assembly (20) is placed on the membrane reforming device (70). Referring to Fig. 12, the actual outer diameter of all of the reform pins (724) at the basic positions is smaller than the diameter of the core hollow portion (29) of the electrode assembly (20). By means of the insertion guide surface (725) at the upper portion of the reform pin (724), the reform pin (724) is inserted into the core hollow portion (29) without deforming the core portion (280) of the separator (28). The membrane reforming device (70) is installed on the lifter (60).

[0113] Referring to FIG. 13, the lifter (60) is raised relative to the can (10) to insert the electrode assembly (20) through the opening of the can (10) to a first position in the internal space. The first position may be a position where an upper portion of the electrode assembly (20) is inserted so that the electrode assembly (20) can stably pass through the opening of the can (10) and be centered with the can (10).

[0114] Referring to Fig. 14, the actuator (74) rises from the first position and comes into contact with the inner slanted surface (723) of the dividing head (722). Accordingly, the dividing head (722) moves radially outward. The length of the outer slanted surface (746) of the actuator (74) is longer than the length of the inner slanted surface (723). Accordingly, as the actuator (74) rises, the dividing head (722) moves radially outward.

[0115] The force applied by the actuator (74) as it moves upward is converted into a force that causes the outer surface of the reform pin (724) to radially outwardly press the separator core portion (280) of the core hollow portion (29) against the inner surface of the electrode assembly (20). Therefore, by adjusting the upward pressing force of the actuator (74), the pressure applied by the reform pin (724) to press the separator core portion (280) against the inner surface of the electrode assembly (20) can be adjusted.

[0116] As illustrated in Fig. 15, the reform pin (724) can press the separator core portion (280) against the inner surface of the electrode assembly (20). Accordingly, the separator core portion (280) is reformed.

[0117] Preferably, the reform pin (724) can press the separator core part (280) against the inner circumferential surface of the electrode assembly (20) while being heated by the heating part (75). The heat generated from the heating part (75) can be conducted to the reform pin (724) through the dividing head (722). Accordingly, the separator core part (280) is hot reformed. The reform pin (724) can be continuously heated by the heating part or can be heated during hot reforming.

[0118] Referring to Fig. 16, the lifter (60) can be further raised to insert the electrode assembly (20) into the can (10) to a second position. The second position may be the final insertion position.

[0119] Referring to FIGS. 17 and 18, when the electrode assembly (20) is inserted to the final position, the actuator (74) is lowered. Then, the dividing head (722) moves radially inward toward the basic position by the coil spring (76). Accordingly, the reform pin (724) is retracted from the inner surface of the electrode assembly (20). By the reform pin (724), the core portion (280) of the separator is reformed into a form in which it is tightly fixed to the inner surface of the electrode assembly (20).

[0120] Referring to Fig. 19, the reform pin (724) is retracted radially inward and is in the basic position, and the lifter (60) moves away from the can holder (50) to remove the reform pin (724) from the core hollow portion (29) of the electrode assembly (20).

[0121] Referring to Fig. 20, when the electrode assembly (20) is accommodated in the internal space of the can (10), the first collector plate (30) installed at the axial first end of the electrode assembly (20) faces the end wall (12) and the first electrode terminal (17), and the second collector plate (40) installed at the axial second end of the electrode assembly (20) faces the opening. The insulator (19) interposed between the first collector plate (30) and the end wall (12) in the axial direction electrically insulates the first collector plate (30) from the end wall (12).

[0122] After the insertion of the electrode assembly (20) is completed, the terminal joint (320) of the first current collector (30) is joined to the bottom surface of the first electrode terminal (17) by welding or the like. In one example, the joining can be performed by inserting a welding rod through the core hollow portion (29) of the electrode assembly (20). Accordingly, the first electrode terminal (17) and the first electrode (21) of the electrode assembly (20) are electrically connected to each other through the first current collector (30).

[0123] The edge portion (42) of the second collector plate (40) may be in contact with or joined to the side wall (11) and may be electrically connected to the side wall (11). Since the end wall (12) is electrically connected to the side wall (11), the end wall (12) forms a second electrode terminal having a different polarity from the first electrode terminal (17).

[0124] According to the embodiment, since the process of inserting the electrode assembly (20) into the can (10) is performed while the reform pin (724) brings the core portion (280) of the separator (28) into close contact with the inner surface of the electrode assembly (20), it is possible to prevent gas in the inner space of the can that escapes through the core hollow portion (29) from loosening or deforming the core portion (280) of the separator (28). In addition, since the insertion process of the electrode assembly (20) and the separator reforming process are performed simultaneously, the process time can be shortened.

[0125] It should be understood that the above-described embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be determined by the claims that follow, rather than by the detailed description set forth above. Furthermore, the meaning and scope of the claims that follow, as well as all possible modifications and variations derived from their equivalent concepts, should be construed as encompassing the scope of the present invention.

[0126] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. Body part supporting the bottom of the electrode assembly; A head section having a plurality of dividing heads installed on the upper portion of the body section so as to be able to reciprocate radially about the center; and A membrane reforming device, comprising: a reforming pin connected to each dividing head at the center of the head portion and extending upward in the axial direction from the dividing head so as to be inserted into the core hollow portion of the electrode assembly; 2. A membrane reforming device according to claim 1, further comprising an actuator that moves the dividing head radially outward.

3. A membrane reforming device further comprising a return member for returning the dividing head radially inward in claim 1.

4. A membrane reforming device further comprising a heating unit for heating the reforming pin according to claim 1.

5. In claim 1, the body portion has a first guide portion extending radially to guide radial movement of each of the dividing heads, A membrane reforming device, wherein each of the above-mentioned dividing heads has a second guide portion that contacts the first guide portion and radially swivels.

6. In claim 1, the actuator is installed in the body so as to be able to move upward and downward in the axial direction, A membrane reforming device having a contact portion provided on the radially inner side of the above-mentioned dividing head in contact with the above-mentioned actuator.

7. In claim 6, the upper part of the actuator is provided with an outer slanted surface whose outer diameter gradually decreases upward. A membrane reforming device having an inner sloping surface whose inner diameter gradually decreases as it goes upwards, provided at the above contact portion.

8. A membrane reforming device according to claim 3, wherein the return member is an elastic body that elastically supports the dividing head radially inward.

9. A membrane reforming device according to claim 4, wherein the heating unit heats the reforming pin by a resistance heating method.

10. A membrane reforming device according to claim 4, wherein the reforming pin is heated to 120 to 140 degrees Celsius by the heating unit.

11. A can holder that supports the can so that the opening of the inner space faces downward; A lifter for inserting the electrode assembly axially upward through the opening at the bottom of the can holder; and An electrode assembly insertion device comprising a membrane reforming device according to any one of claims 1 to 10 installed on the above lifter.

12. A method for reforming a separator portion provided in a core hollow portion of an electrode assembly using an electrode assembly insertion device of claim 11, A step of inserting the reform pin of the separator reforming device, in which the dividing head is positioned radially inwardly in the core hollow portion of the electrode assembly, into the first position of the internal space of the can through the opening of the can using the lifter; and A method for reforming a membrane, comprising: a step of operating the actuator so that the dividing head moves radially outward at the first position, thereby bringing the membrane portion into close contact with the inner circumference of the core hollow portion using the reform pin; 13. A method for reforming a membrane, further comprising the step of heating the reform pin to hot reform the membrane portion in close contact with the inner circumference of the core hollow portion of claim 12.

14. A method for reforming a membrane, further comprising the step of inserting the electrode assembly to a second position deeper than the first position using the lifter in claim 12.

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