Electrode stacking device

Abstract

The present invention provides a structure of an electrode stacking device having a tension compensation unit for applying a compensatory tension to a widthwise central portion of a separator in order to prevent a phenomenon in which the central portion and both end portions of the separator are non-uniformly tensioned and deformed in a zigzag stacking process.

Description

Electrode stacking device

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0061913, dated May 10, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a structure of an electrode stacking device used in a zigzag stacking method for manufacturing an electrode assembly built into a secondary battery cell.

[0003] Secondary batteries, which boast high electrical properties such as high energy density and easy applicability across a wide range of product groups, are widely used not only in portable devices but also in electric or hybrid vehicles powered by electrical power sources, as well as in power storage devices. These batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency, not only because they can dramatically reduce fossil fuel use, but also because they produce no byproducts from energy use.

[0004] While small mobile devices typically use one or two or three battery cells per device, medium- to large-sized devices, such as automobiles, require high output and large capacity. Therefore, medium- to large-sized battery modules or packs consisting of multiple battery cells electrically connected are used.

[0005] Meanwhile, known types of unit secondary battery cells include cylindrical, prismatic, and pouch-shaped battery cells. Since it is desirable for mid- to large-sized battery modules to be manufactured with as small a size and weight as possible, prismatic and pouch-shaped batteries, which can be stacked with high integration and have a small weight per capacity, are primarily used as battery cells for mid- to large-sized battery modules.

[0006] Among these, pouch-type battery cells have various structures depending on the manufacturing method of the electrode assembly they contain. In particular, recently, high-capacity stacked cell type electrode assemblies are often manufactured at high speed using the zigzag stacking method, which alternately laminates positive and negative electrodes between each layer of a zigzag-folded separator.

[0007] Figures 1 to 6 illustrate a process of stacking a separator and electrodes through zigzag stacking. Referring to these drawings, zigzag stacking is performed by alternately stacking first electrodes (11) and second electrodes (12) having different polarities with a zigzag-folded separator (13). At this time, the separator (13) is continuously supplied from a nip roll (3) to a stack table (2) that reciprocates between a first relative position and a second relative position, and is folded while wrapping around a first mandrel (21) and a second mandrel (22) that move together with the stack table (2) and alternately grip the separator (13), thereby forming a folding portion (133, 134).

[0008] Fig. 7 shows a state in which tensile deformation occurs in the separator. Referring to this, the first mandrel (21) and the second mandrel (22) are provided as a pair, each spaced apart from each other by a predetermined distance (D) along the width direction of the separator (13). Accordingly, when the stack table (2) is displaced from the second relative position to the second relative position, tension is applied between the portion gripped by the second mandrel (22) and the nip roll (3). At this time, in the separator (13), the portion gripped by the second mandrel (22) is mainly subjected to tensile deformation, and the portion located between the pair of second mandrels (22) is hardly deformed, but the portion close to the second mandrel (22) portion is slightly deformed due to frictional force with the second mandrel (22).

[0009] This non-uniform tensile deformation of the above-mentioned separator (13) causes warping or dimensional oversize in the completed electrode assembly, which in turn causes structural and functional defects. Therefore, a technical means to resolve this is urgently needed.

[0010] The present invention was created under the background of the above-described prior art, and its purpose is to provide a structure of an electrode stacking device that prevents non-uniform tensile deformation of a separator in an electrode stacking device that manufactures an electrode assembly through zigzag stacking.

[0011] Specifically, the present invention aims to prevent non-uniform tensile deformation caused by non-uniform tension applied to the separator by a mandrel that holds the separator for folding.

[0012] The present invention also seeks to provide a structure of an electrode lamination device capable of manufacturing an electrode assembly without defects such as warping or oversize due to deformation of a separator.

[0013] 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.

[0014] In order to solve the above problem, the present invention comprises: a stack table on which first electrodes and second electrodes are alternately stacked with a separator interposed therebetween, the separator being continuously provided with a predetermined width in the front-back direction and folded in a zigzag manner so that the first side and the second side are alternately exposed; a pair of nip rolls arranged vertically apart from the stack table to regulate a supply position of the separator supplied to the stack table, and arranged symmetrically left and right with respect to a predetermined plane of symmetry; a driving unit displacing a relative position of the stack table with respect to the nip rolls between a first relative position set to the left with respect to the plane of symmetry and a second relative position set to the right with respect to the plane of symmetry; a pair of first mandrels arranged spaced apart from each other by a predetermined distance in the front-back direction, the first side of the separator being pressed against the stack table at least when the stack table is displaced from the first relative position to the second relative position, and defining a right folding portion of the separator; The present invention provides a structure of an electrode stacking device including a pair of first mandrels arranged at a predetermined distance apart from each other in the forward-reverse direction and configured to press the second surface of the separator against the stack table and define a left folding portion of the separator at least when the stack table is displaced from the second relative position to the first relative position; and a tension compensating portion configured to press the surface of the separator at least temporarily.

[0015] The tension compensation unit according to the present invention is configured to apply compensatory tension to the widthwise central portion of the separator in order to prevent the phenomenon of the widthwise central portion and both ends being non-uniformly tensilely deformed as the separator is gripped at its widthwise ends by the first mandrel and the second mandrel.

[0016] According to one embodiment, the tension compensation unit may include a first tension compensation unit and a second tension compensation unit that are arranged symmetrically with respect to the symmetry plane. The first tension compensation unit and the second tension compensation unit may have a fixed relative position with respect to the nip roll.

[0017] The first tension compensation unit may be positioned on the left side of the symmetry plane and may pressurize the separator in at least a portion of a section in which the stack table is displaced from the second relative position to the first relative position. At this time, the surface pressed by the first tension compensation unit may be the first surface of the separator.

[0018] The second tension compensation unit may be positioned on the right side with respect to the symmetry plane and may pressurize the separator in at least a portion of a section in which the stack table is displaced from the first relative position to the second relative position. At this time, the surface pressed by the second tension compensation unit may be the second surface of the separator.

[0019] At this time, the separation membrane may be bent in an extension direction based on the nip roll, the first tension compensation unit, and the second mandrel at least immediately after the stack table is displaced to the first relative position, and may be bent in an extension direction based on the nip roll, the second tension compensation unit, and the first mandrel at least immediately after the stack table is displaced to the second relative position.

[0020] According to one variation, the tension compensation unit can be displaced in conjunction with the stack table. That is, the tension compensation unit can have a fixed relative position with respect to the stack table.

[0021] In this case, the tension compensation unit can pressurize the second surface of the separator in at least a portion of a section in which the stack table is displaced from the second relative position to the first relative position, and can pressurize the first surface of the separator in at least a portion of a section in which the stack table is displaced from the first relative position to the second relative position.

[0022] At this time, the tension compensation unit may be positioned so as not to interfere with the separator before the first electrode or the second electrode is stacked after the stack table is displaced to the first relative position or the second relative position, and then to interfere with the separator again before the stack table is displaced to the second relative position or the first relative position after the first electrode or the second electrode is stacked.

[0023] Specifically, according to one aspect of the present invention, the tension compensation portion may have a shape that extends a predetermined length in the front-rear direction, and may have a shape in which the front-rear central portion thereof protrudes toward the separator compared to the front-rear ends thereof. In other words, the tension compensation portion may be formed so that, when the separator approaches to contact the tension compensation portion, the front-rear central portion thereof comes into contact with the separator first compared to the front-rear ends thereof. Accordingly, the tension compensation portion may apply a greater tension to the widthwise central portion of the separator than to the widthwise ends of the separator, and may compensate for tension unevenly applied to the separator by the first mandrel and the second mandrel.

[0024] According to one embodiment of the present invention, the tension compensation unit may include a roll shape having a concentric circular cross-section along the forward-backward direction. It is preferable that the tension compensation unit be installed so as to be able to rotate along the progress of the separator. At this time, the diameter of the tension compensation unit may be larger at the center in the forward-backward direction than at the front-back and rear-end portions thereof. In this case, the tension compensation unit may not generate unnecessary friction with the separator, thereby preventing excessive deformation or damage to the separator. However, the shape of the tension compensation unit may be sufficient as long as it extends along the forward-backward direction and the center in the forward-backward direction thereof protrudes toward the separator compared to the front-back and rear-end portions thereof, and it is not necessarily required to be installed so as to be able to rotate or to have a roll shape.

[0025] According to one embodiment of the present invention, the diameter of the tension compensation portion may have a shape that increases from the front and rear ends thereof to the front and rear center thereof. Since the separation membrane is subjected to increasingly greater tensile deformation from the widthwise center thereof to the ends thereof due to the tension and frictional force provided by the first mandrel or the second mandrel, the tension compensation portion may compensate for such deformation by having a shape corresponding thereto.

[0026] In addition, it is preferable that the rate of increase in the diameter of the tension compensation portion decreases from the front and rear ends toward the center in the front and rear direction. Accordingly, the actual degree of tensile deformation received by the separator can be accurately compensated, and the area where the tension compensation portion and the separator come into contact with each other forms a smooth curve without sharp points, thereby preventing damage to the separator.

[0027] According to a special example, the tension compensation part may include a tapered part whose diameter increases toward the center of the front-rear direction in some of its sections, even if the diameter does not increase or decrease along the entire section along the front-rear direction.

[0028] Additionally, the predetermined length may be equal to or smaller than the predetermined width. That is, the tension compensation portion may be formed to contact only a portion of the central portion of the separation membrane, rather than the entire widthwise portion of the separation membrane.

[0029] In particular, the predetermined length may be equal to or less than the predetermined distance. In this case, the tension compensation unit may not apply tension to a portion that receives tension from the first mandrel or the second mandrel.

[0030] According to another aspect of the present invention, the tension compensation member may have a shape that extends along the front-rear direction by a predetermined first length that is equal to or smaller than the predetermined width. That is, the tension compensation member may be formed so as to contact not the entire widthwise section of the separator, but only a portion of the central section thereof. Accordingly, the tension compensation member may apply a greater tension to the widthwise central section of the separator than to the widthwise ends of the separator, and may compensate for tension unevenly applied to the separator by the first mandrel and the second mandrel.

[0031] According to another embodiment of the present invention, the tension compensation unit may include a roll shape having a concentric circular cross-section along the forward-backward direction. It is preferable that the tension compensation unit be installed so as to be rotatable and to rotate along the progress of the separator. At this time, the diameter of the tension compensation unit may be larger at the center in the forward-backward direction than at the forward-backward ends thereof. In this case, the tension compensation unit may not generate unnecessary friction with the separator, thereby preventing excessive deformation or damage to the separator. However, the shape of the tension compensation unit is sufficient as long as the first length is smaller than the width of the separator, and it is not necessarily required to be installed so as to be rotatable or to have a roll shape.

[0032] According to another embodiment of the present invention, the tension compensation unit may include: a pair of tapered portions whose diameter increases toward the center in the front-rear direction; and a flat portion extending by a predetermined second length and connecting the pair of tapered portions with a constant diameter. Accordingly, the pressure applied to the separator by the tension compensation unit is prevented from being concentrated at the end of the tension compensation unit, thereby preventing the separator from being excessively deformed or damaged.

[0033] At this time, it is preferable that the second length is equal to or smaller than the predetermined distance. In this case, the flat portion applies tension to a portion of the separator where the first mandrel and the second mandrel do not apply tension, and the tapered portion can prevent an overlap in the degree of deformation at the boundary between a portion where the tension compensation portion applies tension and a portion where the first mandrel and the second mandrel apply tension. In addition, at this time, since tensile deformation may occur up to a portion located wider inward in the width direction than a portion of the separator that comes into contact with the first mandrel due to a frictional force between the first mandrel and the second mandrel, it is preferable that the second length be set sufficiently smaller than the predetermined distance.

[0034] According to another embodiment of the present invention, the first length may be formed to be larger than the predetermined distance and smaller than the predetermined width.

[0035] According to a special example, the first length may be equal to or less than the predetermined distance. In this case, the tension compensation unit may not apply tension to a portion that receives tension from the first mandrel or the second mandrel.

[0036]

[0037] The present invention also comprises: a stack table on which first electrodes and second electrodes are alternately stacked with a separator interposed therebetween, the separator being continuously provided with a predetermined width in the front-back direction and being folded in a zigzag manner so that the first and second surfaces are alternately exposed; a pair of nip rolls having a shape extending by a predetermined length in the front-back direction and spaced apart from the stack table vertically to regulate a supply position of the separator supplied to the stack table, and arranged symmetrically left and right with respect to a predetermined plane of symmetry; a driving unit that displaces a relative position of the stack table with respect to the nip rolls between a first relative position set to the left with respect to the plane of symmetry and a second relative position set to the right with respect to the plane of symmetry; a pair of first mandrels spaced apart by a predetermined distance in the front-back direction, and pressing a first surface of the separator against the stack table and defining a right folding portion of the separator at least when the stack table is displaced from the first relative position to the second relative position; And a pair of first mandrels arranged at a predetermined distance apart from each other in the front-back direction, and pressing the second surface of the separator against the stack table at least when the stack table is displaced from the second relative position to the first relative position and defining a left folding portion of the separator; wherein the diameter of each of the nip rolls is larger at a portion corresponding to the widthwise central portion of the separator than at portions corresponding to the widthwise opposite ends of the separator.

[0038] In other words, the tension compensation unit according to the present invention may be included in the nip roll or may be the nip roll itself. That is, according to the present invention, the effect of preventing the phenomenon of the widthwise central portion and both ends of the separator being tensilely deformed non-uniformly by applying compensatory tension to the widthwise central portion of the separator can be obtained not only when the tension compensation unit is provided separately, but also when the shape or dimensions of the nip roll are changed.

[0039] At this time, the diameter of each of the nip rolls is larger at a portion corresponding to the widthwise central portion of the separator than at a portion corresponding to the widthwise ends of the separator, which also includes a case where the predetermined length is smaller than the predetermined width and the nip roll does not have a portion corresponding to the widthwise ends of the separator or has a diameter of 0.

[0040] In this case, it will be apparent from the description of this specification that the shape of the tension compensation part described above can be referenced when configuring the specific shape of the nip roll.

[0041] The present invention can provide a structure of an electrode stacking device in which a uniform tension can be applied along the width of a separator.

[0042] According to one embodiment of the present invention, a structure of an electrode stacking device is provided that enables tensile deformation of a separator to occur evenly by having a tension compensating portion that applies compensatory tension to the non-uniform tension applied to the separator by a mandrel.

[0043] Accordingly, the electrode stacking device according to the present invention can manufacture an electrode assembly with minimized defects due to dimensional oversize or warping caused by deformation of the separator.

[0044] In addition, the present invention may have various other effects, which will be described in each embodiment, or the description of effects that can be easily inferred by a person skilled in the art will be omitted.

[0045] Figures 1 to 6 illustrate the process of stacking a separator and electrodes through zigzag stacking.

[0046] Figure 7 shows the appearance of a tensile deformation occurring in a separator.

[0047] Figure 8 illustrates an electrode stacking device according to one embodiment of the present invention.

[0048] Figure 9 shows a process of laminating electrodes according to one embodiment of the present invention.

[0049] Figure 10 shows the process of laminating electrodes according to the first modified example.

[0050] Figure 11 shows the electrode lamination process according to the second modified example.

[0051] Fig. 12 shows the shape of a tension compensation part according to one embodiment of the present invention.

[0052] Fig. 13 shows the shape of a tension compensation part according to another embodiment of the present invention.

[0053] [Explanation of symbols]

[0054] 11: First electrode 12: Second electrode 13: Separator 131: First surface 132: Second surface 133: Left folding part 134: Right folding part 2: Stack table 20: Drive part 21: First mandrel 22: Second mandrel 3: Nip roll 4: Transfer means 51: (First) tension compensation part 510: Taper part 511: Flat part 52: Second tension compensation part S: Symmetrical plane W: Width D: Distance L: Length L1: First length L2: Second length D1: First diameter D2: Second diameter

[0055] 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.

[0056] Although the terms "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0057] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0058] 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.

[0059] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0060] 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.

[0061] 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.

[0062] For convenience, expressions related to directions such as up-down, left-right, and front-back are used in this specification, but these are not absolute directions related to the direction of gravity or any geopolitical direction. For example, up-down, left-right, and front-back used in this specification are sufficiently understood to mean any three directions in which each of them intersects with the other two.

[0063]

[0064] Hereinafter, a preferred embodiment of the present invention will be described with reference to the attached drawings.

[0065]

[0066] [Typical zigzag stacking process]

[0067] Figures 1 to 6 illustrate a process of stacking a separator and electrodes through zigzag stacking. Specifically, Figures 1 to 6 illustrate the states of an electrode stacking device in steps 1 to 6, which are repeatedly performed in a zigzag stacking process, respectively. Referring to these drawings, the electrode stacking device includes a stack table (2), a driving unit (20), a first mandrel (21), a second mandrel (22), a nip roll (3), and a conveying means (4).

[0068] On the above stack table (2), the first electrode (11) and the second electrode (12) are alternately stacked with a separator (13) interposed therebetween.

[0069] The above-mentioned nip roll (3) and the above-mentioned stack table (2) are arranged spaced apart from each other vertically.

[0070] As shown in Fig. 1, the nip roll (3) is a pair of rotatable roll-shaped members arranged symmetrically left and right based on an imaginary plane of symmetry (S), and the separator (13) runs between the pair of nip rolls (3) and is continuously supplied from a predetermined supply position regulated by the nip roll (3). At this time, the separator (13) is a sheet-shaped member extending with a predetermined width (W), and is supplied by being unwound from the separator roll.

[0071] The stack table (2) is driven by the driving unit (20) to reciprocate between a predetermined first relative position and a second relative position with respect to the symmetry plane (S). Specifically, the driving unit (20) rotates the stack table (2) about a central axis spaced vertically from the stack table (2), and reciprocates between the first relative position and the second relative position spaced along the circumferential direction of the rotation at a predetermined cycle.

[0072] The first mandrel (21) and the second mandrel (22) are installed to reciprocate with the stack table (2) about the central axis. The first mandrel (21) and the second mandrel (22) are arranged to be spaced apart from each other in the left-right direction with respect to the stack table (2). The first mandrel (21) and the second mandrel (22) are each provided as a pair spaced apart from each other by a predetermined distance in the front-back direction.

[0073] The above first mandrel (21) presses the first surface (131) of the separator (13) against the stack table (2) at least when the stack table (2) is displaced from the first relative position to the second relative position, and defines the right folding portion (134) of the separator (13).

[0074] Specifically, referring to FIGS. 1 to 4, the first mandrel (21) releases the pressure on the separator (13) in the first step, and presses the first surface (131) of the separator (13) against the stack table (2) again in the second step. In the third step, the transport means (4) transports the first electrode (11) and stacks it on the first surface (131) of the separator (13). In the fourth step, the stack table (2) is displaced to the second relative position, so that the separator (13) is folded while wrapping around the first mandrel (21) to form the right folding portion (134).

[0075] Likewise, the second mandrel (22) presses the second surface (132) of the separator (13) against the stack table (2) and defines the left folding portion (133) of the separator (13) at least when the stack table (2) is displaced from the second relative position to the first relative position.

[0076] Specifically, referring to FIGS. 4 to 6 and 1, the second mandrel (22) releases the pressure on the separator (13) in the fourth step, and presses the first surface (131) of the separator (13) against the stack table (2) in the fifth step. In the sixth step, the transport means (4) transports the second electrode (12) and stacks it on the second surface (132) of the separator (13). In the first step, the stack table (2) is displaced to the first relative position, so that the separator (13) is folded while wrapping around the second mandrel (22) to form the left folding portion (133).

[0077] As the above steps 1 to 6 are repeated several times, an electrode assembly having a structure in which the first electrode (11) and the second electrode (12) are alternately and repeatedly laminated with each layer of the separator (13) folded in a zigzag pattern is manufactured.

[0078] At this time, in order to ensure accurate supply speed and smooth operation of the separator (13), a predetermined tension is continuously applied to the separator (13).

[0079] Fig. 7 shows a state in which tensile deformation occurs in the separator. Referring to this, in the first step, as the separator (13) is folded while being pressed by the second mandrel (22), the second mandrel (22) provides a reaction force to the tension applied to the separator (13). At this time, a certain section of the widthwise ends of the separator (13) that contact the second mandrel (22) receives a greater tension than the widthwise central portion, causing non-uniform tensile deformation to occur in the separator (13). As a result, the right folding portion (134) undergoes deformation in which the widthwise central portion sags inward, and the portion adjacent to the inner end of the second mandrel (22) is somewhat tensilely deformed in the widthwise direction of the separator (13) due to the frictional force applied by the second mandrel (22).

[0080] This phenomenon can occur equally with respect to the first mandrel (21) as well as the second mandrel (22). That is, in the fourth step, as the first mandrel (21) presses the separator (13) and provides a counter force to the tension, sagging due to non-uniform tensile deformation can also occur in the left folding portion (133).

[0081] The features of the present invention described below were devised to address these issues. However, the present invention is not necessarily applicable only to electrode assembly devices having the above-described structure and performing the above-described process.

[0082]

[0083] [Placement of tension compensation unit]

[0084] An electrode stacking device according to one embodiment of the present invention includes the structure of the electrode stacking device described from FIGS. 1 to 6, and manufactures an electrode assembly by repeatedly performing steps 1 to 6 similar to steps 1 to 6. The electrode assembly device according to this embodiment is characterized in that it additionally includes a tension compensation unit to be described below. However, it should be understood that the present invention also includes a case where the tension compensation unit to be described below is applied to another type of electrode stacking device for zigzag stacking.

[0085] Hereinafter, with reference to FIGS. 8 to 11, the structure of the electrode stacking device according to the present invention and the arrangement and operation of the tension compensation unit are exemplified.

[0086] Fig. 8 illustrates an electrode stacking device according to one embodiment of the present invention. Referring to this, the electrode stacking device according to the present invention is characterized by including a tension compensation unit (51) configured to at least temporarily pressurize the surface of the separator (13).

[0087] The tension compensation unit (51) according to the present invention is configured to apply compensatory tension to the widthwise central portion of the separation membrane (13) in order to prevent the phenomenon of the widthwise central portion and both ends being tensilely deformed non-uniformly as the separation membrane (13) is gripped at its widthwise ends by the first mandrel (21) and the second mandrel (22).

[0088] Fig. 9 illustrates a process of laminating electrodes according to one embodiment of the present invention. Referring to this, the tension compensation unit (51) according to one embodiment of the present invention may include a first tension compensation unit (51) and a second tension compensation unit (52) that are arranged symmetrically to each other with respect to the plane of symmetry (S). The first tension compensation unit (51) and the second tension compensation unit (52) may have a fixed relative position with respect to the nip roll (3).

[0089] The first tension compensation unit (51) is positioned on the left side with respect to the symmetry plane (S) and can pressurize the separation membrane (13) in at least a portion of a section in which the stack table (2) is displaced from the second relative position to the first relative position. Specifically, the first tension compensation unit (51) can apply pressure to the separation membrane (13) throughout the sixth step (S6), the first step (S1), and the second step (S2). However, the first tension compensation unit (51) may be arranged so as to pressurize the separation membrane (13) only in the first step (S1). In this case, the surface pressed by the first tension compensation unit (51) may be the first surface (131) of the separation membrane (13).

[0090] The second tension compensation unit (52) is positioned on the right side with respect to the symmetry plane (S) and can pressurize the separation membrane (13) in at least a portion of a section in which the stack table (2) is displaced from the first relative position to the second relative position. Specifically, the second tension compensation unit (52) can apply pressure to the separation membrane (13) throughout the third step (S3) to the fifth step (S5). However, the second tension compensation unit (52) may be arranged so as to pressurize the separation membrane (13) only in the fourth step (S4). In this case, the surface pressed by the second tension compensation unit (52) may be the second surface (132) of the separation membrane (13).

[0091] At this time, the separation membrane (13) may be bent in the extension direction starting from the nip roll (3), the first tension compensation unit (51), and the second mandrel (22) at least in the first step (S1), and may be bent in the extension direction starting from the nip roll (3), the second tension compensation unit (52), and the first mandrel (21) at least in the fourth step (S4).

[0092] Fig. 10 illustrates a process of stacking electrodes according to a first modified example. Referring to this, the tension compensation unit (51) according to the first modified example can be displaced in conjunction with the stack table (2). That is, the tension compensation unit (51) can have a fixed relative position with respect to the stack table (2).

[0093] In this case, the tension compensation unit (51) can pressurize the second surface (132) of the separation membrane (13) in at least a portion of a section in which the stack table (2) is displaced from the second relative position to the first relative position, and can pressurize the first surface (131) of the separation membrane (13) in at least a portion of a section in which the stack table (2) is displaced from the first relative position to the second relative position. Specifically, the tension compensation unit (51) can pressurize the separation membrane (13) in the first step (S1) and the fourth step (S4), respectively.

[0094] At this time, the tension compensation unit (51) may be positioned to avoid interfering with the separator (13) before the first electrode (11) or the second electrode (12) is stacked after the stack table (2) is displaced to the first relative position or the second relative position, that is, in the second step (S2) and the fifth step (S5), and then to interfere with the separator (13) again before the stack table (2) is displaced to the second relative position or the first relative position after the first electrode (11) or the second electrode (12) is stacked, that is, between the second step (S2) and the fourth step (S4) and between the fifth step (S5) and the first step (S1).

[0095] Fig. 11 shows a process of laminating electrodes according to a second modified example. Referring to this, the tension compensation part according to the second modified example may be included in the nip roll (3) or may be the nip roll (3) itself. That is, according to the present embodiment, the effect of preventing the phenomenon of the widthwise central part and both ends of the separator (13) being non-uniformly tensilely deformed by applying compensatory tension to the widthwise central part of the separator (13) can be obtained not only when the tension compensation part is provided separately, but also when the shape or dimensions of the nip roll (3) are changed.

[0096] Specifically, the nip roll located on the left side of the pair of nip rolls (3) can apply pressure to the separator (13) throughout the sixth step (S6), the first step (S1), and the second step (S2). At this time, the surface that the first tension compensation unit (51) applies pressure to may be the first surface (131) of the separator (13).

[0097] Likewise, the nip roll located on the right side of the pair of nip rolls (3) can apply pressure to the separator (13) through the second tension compensation unit (52) from the third step (S3) to the fifth step (S5). At this time, the surface that the second tension compensation unit (52) applies pressure to may be the second surface (132) of the separator (13).

[0098]

[0099] [Shape of tension compensation part]

[0100] The tension compensation unit according to the present invention may have a dimension or shape set to apply a compensatory tension to the separator for the tensile force applied by the first mandrel and the second mandrel. Meanwhile, although FIGS. 12 and 13 below both illustrate the first tension compensation unit placed in the first step, the solution to the problem related to the shape and dimension of the tension compensation unit described below can be applied independently of the arrangement of the tension compensation unit described above, that is, to all of the above-described embodiment, first modified example, and second modified example of the present invention. Hereinafter, the shape of the tension compensation unit according to the present invention will be exemplified with reference to FIGS. 12 and 13.

[0101] Fig. 12 shows the shape of a tension compensation unit according to one embodiment of the present invention. Referring to this, the tension compensation unit (51) according to one embodiment of the present invention may have a shape that extends by a predetermined length (l) in the front-rear direction, and a shape in which the front-rear central portion thereof protrudes toward the separator (13) compared to the front-rear ends thereof. In other words, the tension compensation unit (51) may be formed so that, when the separator (13) approaches to make contact with the tension compensation unit (51), the front-rear central portion thereof makes contact with the separator (13) first compared to the front-rear ends thereof. Accordingly, the tension compensation unit (51) may apply a greater tension to the widthwise central portion of the separator (13) than to the widthwise ends thereof, and may compensate for tension unevenly applied to the separator (13) by the first mandrel (21) and the second mandrel (22).

[0102] According to one embodiment of the present invention, the tension compensation unit (51) may include a roll shape having a concentric circular cross-section along the front-rear direction. It is preferable that the tension compensation unit (51) be installed so as to be able to rotate along the progress of the separator (13). At this time, the first diameter (D1) at the front-rear end portions of the tension compensation unit (51) may be smaller than the second diameter (D2) at the front-rear central portion of the tension compensation unit (51). In this case, the tension compensation unit (51) may not generate unnecessary friction with the separator (13), and thus may not cause excessive deformation or damage to the separator (13). However, the shape of the tension compensation unit (51) is sufficient as long as it extends along the front-rear direction and the front-rear central portion thereof protrudes toward the separator (13) compared to the front-rear end portions thereof, and it is not necessarily required to be installed so as to be able to rotate or to have a roll shape.

[0103] According to one embodiment of the present invention, the diameter of the tension compensation part (51) may have a shape that increases from its front and rear ends toward its front and rear center. Since the separation membrane (13) is increasingly tensilely deformed from its widthwise center toward its ends due to the tension and frictional force provided by the first mandrel (21) or the second mandrel (22), the tension compensation part (51) can compensate for this deformation by having a shape corresponding thereto.

[0104] In addition, it is preferable that the rate of increase in the diameter of the tension compensation portion (51) decreases from its front and rear ends toward its front and rear center. Accordingly, the actual degree of tensile deformation received by the separator (13) can be accurately compensated, and the area where the tension compensation portion (51) and the separator (13) come into contact with each other forms a smooth curve without sharp points, thereby preventing damage to the separator (13).

[0105] Fig. 13 shows the shape of a tension compensation unit according to another embodiment of the present invention. Referring to these drawings, the tension compensation unit (51) according to another embodiment of the present invention may have a shape that extends in the front-rear direction by a predetermined first length (L1) that is equal to or smaller than the predetermined width (W). That is, the tension compensation unit (51) may be formed so as to contact only a portion of the central portion thereof, rather than the entire widthwise portion of the separator (13). Accordingly, the tension compensation unit (51) may apply a greater tension to the widthwise central portion of the separator (13) than to the widthwise ends thereof, and may compensate for tension unevenly applied to the separator (13) by the first mandrel (21) and the second mandrel (22).

[0106] According to another embodiment of the present invention, the tension compensation part (51) may include a roll shape having a concentric circular cross-section along the front-rear direction. It is preferable that the tension compensation part (51) be installed so as to be able to rotate along the progress of the separator (13). At this time, the diameter of the tension compensation part (51) may be larger at the center in the front-rear direction than at the front-rear ends thereof. In this case, the tension compensation part (51) may not generate unnecessary friction with the separator (13), and thus may not cause excessive deformation or damage to the separator (13). However, the shape of the tension compensation part (51) is sufficient as long as the first length (L1) is smaller than the width (W) of the separator (13), and it is not necessarily necessary to be installed so as to be able to rotate or to have a roll shape.

[0107] According to another embodiment of the present invention, the tension compensation part (51) may include: a pair of tapered parts (510) whose diameter increases toward the center in the front-rear direction; and a flat part (511) that extends by a predetermined second length (L2) and connects the pair of tapered parts (510) with a constant diameter. Accordingly, the pressure applied to the separator (13) by the tension compensation part (51) is prevented from being concentrated at the end of the tension compensation part (51), thereby preventing the separator (13) from being excessively deformed or damaged.

[0108] At this time, it is preferable that the second length (L2) is equal to or smaller than the predetermined distance (D). In this case, the flat portion (511) applies tension to a portion of the separator (13) where the first mandrel (21) and the second mandrel (22) do not apply tension, and the tapered portion (510) can prevent an overlap in the degree of deformation at the boundary between the portion where the tension compensation portion (51) applies tension and the portion where the first mandrel (21) and the second mandrel (22) apply tension. In addition, at this time, since tensile deformation may occur up to a portion located wider inward than the portion in contact with the first mandrel (21) in the separator (13) due to the frictional force between the first mandrel (21) and the second mandrel (22), it is preferable that the second length (L2) be set sufficiently smaller than the predetermined distance (D).

[0109] According to another embodiment of the present invention, the first length (L1) may be formed to be larger than the predetermined distance (D) and smaller than the predetermined width (W).

[0110] According to an example, the first length (L1) may be equal to or less than the predetermined distance (D). In this case, the tension compensation unit (51) may not apply tension to a portion that receives tension from the first mandrel (21) or the second mandrel (22).

[0111]

[0112] 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.

[0113] 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. A stack table in which first and second electrodes are alternately stacked with a separator provided continuously in a front-back direction with a predetermined width and folded in a zigzag pattern so that the first and second sides are alternately exposed; A pair of nip rolls arranged vertically apart from the stack table to regulate the supply position of the separator supplied to the stack table, and arranged symmetrically left and right based on a predetermined symmetry plane; A driving unit that displaces the relative position of the stack table with respect to the nip roll between a first relative position set to the left with respect to the symmetry plane and a second relative position set to the right with respect to the symmetry plane; A pair of first mandrels arranged at a predetermined distance apart in the forward-backward direction and pressing the first surface of the separator against the stack table at least when the stack table is displaced from the first relative position to the second relative position and defining a right folding portion of the separator; A pair of first mandrels arranged at a predetermined distance apart from each other in the forward-backward direction and pressing the second surface of the separator against the stack table at least when the stack table is displaced from the second relative position to the first relative position and defining a left folding portion of the separator; and An electrode stacking device comprising a tension compensating portion configured to be able to at least temporarily pressurize the surface of the separator in a shape extending a predetermined length in the forward-backward direction, wherein the central portion in the forward-backward direction protrudes toward the separator compared to the front-back end portions thereof.

2. In claim 1, the tension compensation part: A first tension compensation unit positioned on the left side with respect to the above symmetry plane and pressurizing the first surface of the separator in at least a portion of the section in which the stack table is displaced from the second relative position to the first relative position; and An electrode stacking device comprising a second tension compensating unit positioned on the right side with respect to the above symmetry plane and pressurizing the second surface of the separator in at least a portion of a section in which the stack table is displaced from the first relative position to the second relative position.

3. In claim 1, the tension compensation unit is displaced in conjunction with the stack table, presses the second surface of the separator in at least a portion of a section in which the stack table is displaced from the second relative position to the first relative position, and presses the first surface of the separator in at least a portion of a section in which the stack table is displaced from the first relative position to the second relative position. An electrode stacking device.

4. In claim 1, the tension compensation part includes a roll shape having a concentric circular cross-section along the front-rear direction, An electrode stacking device in which the diameter of the tension compensation section is larger in the center in the front-back direction than in the front-back and end sections.

5. An electrode stacking device according to claim 4, wherein the diameter of the tension compensation portion increases from the front and rear ends thereof to the center portion in the front and rear direction.

6. An electrode stacking device according to claim 5, wherein the rate of increase in the diameter of the tension compensation portion decreases from the front and rear ends thereof to the front and rear center thereof.

7. An electrode stacking device according to claim 4, wherein the tension compensation portion includes a tapered portion whose diameter increases toward the center in the front-rear direction.

8. An electrode stacking device according to claim 1, wherein the predetermined length is equal to or smaller than the predetermined width.

9. An electrode stacking device according to claim 8, wherein the predetermined length is equal to or smaller than the predetermined distance.

10. A stack table in which first and second electrodes are alternately stacked with a separator provided continuously in a predetermined width in the front-back direction and folded in a zigzag pattern so that the first and second sides are alternately exposed; A pair of nip rolls arranged vertically apart from the stack table to regulate the supply position of the separator supplied to the stack table, and arranged symmetrically left and right based on a predetermined symmetry plane; A driving unit that displaces the relative position of the stack table with respect to the nip roll between a first relative position set to the left with respect to the symmetry plane and a second relative position set to the right with respect to the symmetry plane; A pair of first mandrels arranged at a predetermined distance apart in the forward-backward direction and pressing the first surface of the separator against the stack table at least when the stack table is displaced from the first relative position to the second relative position and defining a right folding portion of the separator; A pair of first mandrels arranged at a predetermined distance apart from each other in the forward-backward direction and pressing the second surface of the separator against the stack table at least when the stack table is displaced from the second relative position to the first relative position and defining a left folding portion of the separator; and An electrode stacking device comprising a tension compensation unit configured to at least temporarily pressurize the surface of the separator, the tension compensation unit having a shape extending along the front-rear direction by a predetermined first length equal to or smaller than the predetermined width.

11. In claim 10, the tension compensation unit: A first tension compensation unit positioned on the left side with respect to the above symmetry plane and pressurizing the first surface of the separator in at least a portion of the section in which the stack table is displaced from the second relative position to the first relative position; and An electrode stacking device comprising a second tension compensating unit positioned on the right side with respect to the above symmetry plane and pressurizing the second surface of the separator in at least a portion of a section in which the stack table is displaced from the first relative position to the second relative position.

12. In claim 10, the tension compensation unit is displaced in conjunction with the stack table, presses the second surface of the separator in at least a portion of a section in which the stack table is displaced from the second relative position to the first relative position, and presses the first surface of the separator in at least a portion of a section in which the stack table is displaced from the first relative position to the second relative position. An electrode stacking device.

13. In claim 10, the tension compensation part includes a roll shape having a circular cross-section along the front-rear direction, An electrode stacking device in which the diameter of the tension compensation section is larger in the center in the front-back direction than in the front-back and end sections.

14. In claim 13, the tension compensation unit: A pair of tapered portions whose diameter increases toward the center in the front-back direction; and An electrode stacking device including a flat portion extending by a predetermined second length and connecting a pair of tapered portions with a constant diameter.

15. An electrode stacking device according to claim 14, wherein the second length is equal to or smaller than the predetermined distance.

16. An electrode stacking device according to claim 10, wherein the first length is equal to or smaller than the predetermined distance.

17. A stack table in which first and second electrodes are alternately stacked with a separator provided continuously in a front-back direction with a predetermined width and folded in a zigzag pattern so that the first and second sides are alternately exposed; A pair of nip rolls arranged in a shape extending a predetermined length in the forward-backward direction and spaced apart from the stack table in an up-and-down direction to regulate the supply position of the separator supplied to the stack table, and arranged symmetrically left and right based on a predetermined symmetry plane; A driving unit that displaces the relative position of the stack table with respect to the nip roll between a first relative position set to the left with respect to the symmetry plane and a second relative position set to the right with respect to the symmetry plane; A pair of first mandrels arranged at a predetermined distance apart in the forward-backward direction and pressing the first surface of the separator against the stack table at least when the stack table is displaced from the first relative position to the second relative position and defining the right folding portion of the separator; and A pair of first mandrels arranged at a predetermined distance apart from each other in the forward-backward direction, and pressurizing the second surface of the separator against the stack table at least when the stack table is displaced from the second relative position to the first relative position, and defining a left folding portion of the separator; An electrode assembly device wherein the diameter of each of the above nip rolls is larger at a portion corresponding to the widthwise central portion of the separator than at a portion corresponding to the widthwise ends of the separator.

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