Manufacturing method for electrode assembly

Abstract

The present invention relates to a method for completing an electrode assembly by finishing an electrode stack, formed through zigzag stacking, with a separator. More specifically, the present invention relates to a specific method for cutting a separator and winding same around an electrode assembly.

Description

Method for manufacturing electrode assembly

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0080635, dated June 20, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a method for manufacturing an electrode assembly and a device therefor, which forms an electrode assembly by finishing an electrode laminate formed through zigzag stacking.

[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 are manufactured by housing electrode assemblies in a pouch. At this time, the electrode assemblies are composed of positive and negative electrodes alternately stacked with a separator interposed between them. These electrode assemblies have various structures depending on their manufacturing method. Recently, in particular, a zigzag stacking method, in which positive and negative electrodes are alternately stacked between each layer of a zigzag-folded separator, has been frequently used to rapidly manufacture high-capacity stacked cell-type electrode assemblies.

[0007] Fig. 1 shows an electrode laminate formed by completing zigzag stacking, and Fig. 2 shows an electrode laminate formed by pulling the electrode laminate and forming a separator unfolding portion. Referring to these drawings, the electrode laminate (1) is formed by continuously supplying a separator (10) folded in a zigzag manner from a nip roll (21) and stacking the separator (10) together with the positive electrode (11) and the negative electrode (12) on a stack table (20). At this time, for the energy efficiency of the battery, the negative electrode (12) is stacked one more than the positive electrode (11), and accordingly, the total number of electrodes becomes odd.

[0008] The electrode laminate (1) formed in this way is pulled in a state in which it is gripped by a gripper (23), and at this time, a separator (10) is additionally developed from a nip roll (21) to form a separator development unit (100) for finishing the electrode laminate (1). The separator development unit (100) receives tension from a tension roll (22) and maintains a taut state.

[0009] Fig. 3 illustrates a membrane cutting device, and Figs. 4 to 7 illustrate a process of cutting a membrane unfolding portion. Referring to these drawings, the membrane unfolding portion (100) is thermally cut by a cutter (24) while being tensioned between a gripper (23) and a tension roll (22). Specifically, as shown in Figs. 4 to 6, the cutter (24) descends from the upper side of the membrane unfolding portion (100) and then rises, and accordingly, the membrane unfolding portion (100) is cut to form a first end (101) on the electrode laminate (1) side and a second end (102) on the tension roll (22) side.

[0010] Fig. 8 shows the first end of the membrane expansion unit in a thermally deformed state. Referring to this, while the cutter (24) is being raised and lowered as shown in Figs. 4 to 6, heat generated from the cutter (24) is continuously transmitted to the first end (101) and the second end (102). This strong heat can cause thermal deformation of the first end (101) and the second end (102) beyond cutting the membrane (10). In this case, the dimensions or appearance of the completed electrode assembly may be poor, and problems such as short circuits occurring due to poor finishing may also occur, so this is a serious problem that requires a solution.

[0011] Meanwhile, after the membrane unfolding portion (100) is cut by the cutter (24), as shown in FIG. 7, the electrode laminate (1) is pulled by the gripper (23) to undergo a winding process. At this time, the tension roll (22) side of the cut membrane unfolding portion (100) where the second end (102) is formed is fixed to the stack table (20) again and used for manufacturing the electrode laminate (1). For the circulation of this process, the pulling direction of the electrode laminate (1) must be the same as the direction in which the end of the lowest layer of the separator, i.e., the second end (102), is directed, and the electrode laminate (1) is formed in a form in which the uppermost electrode (12T) is stacked on the uppermost layer of the separator (10T).

[0012] Fig. 9 shows a membrane winding device, and Figs. 10 to 16 show a process of winding a membrane unfolding portion onto an electrode laminate. Referring to these drawings, the winding process is performed by the rotation of a mandrel (26) that alternately holds an electrode laminate (1) with a gripper (23). Specifically, the winding process includes: a step in which the gripper (23) holds and pulls the electrode laminate (1) (Fig. 10); a step in which the mandrel (26) holds and rotates the electrode laminate (1) by 180 degrees (Figs. 11, 12); a step in which the mandrel (26) returns to its original position while the gripper (23) holds and rotates the electrode laminate (1) by 13; a step in which the mandrel (26) holds and rotates the electrode laminate (1) by an additional 180 degrees (Figs. 14, 15); The process proceeds in the following order: a step of brushing the remaining portion of the separator expansion section (100) to adhere it to the electrode laminate (1) (Fig. 16);

[0013] In this process, electrode particles are removed from the surface of the uppermost electrode (12T) on the gripper (23) and the mandrel (26). In particular, since the mandrel (26) is released by frictional contact with the uppermost electrode (12T), a large amount of electrode particles may be removed. The problem lies in the fact that the gripper (23) and the mandrel (26) come into contact with the separator (10) again while the electrode particles are still present. Specifically, the upper gripper (231) in contact with the uppermost electrode (12T) in FIG. 10 comes into contact with the separator (10) in FIG. 13, the upper mandrel (261) in contact with the uppermost electrode (12T) in FIG. 11 comes into contact with the separator (10) in FIG. 14, the lower gripper (232) in contact with the uppermost electrode (12T) in FIG. 13 comes into contact with the separator (10) in FIG. 10, and the lower mandrel (262) in contact with the uppermost electrode (12T) in FIG. 14 comes into contact with the separator (10) in FIG. 11. In this process, if electrode particles adhere to the surface of the separator (10), this may cause not only a poor appearance but also performance problems such as a short circuit or reduced battery efficiency. Therefore, the problem of such electrode particle adherence is also a task that must be solved.

[0014] The present invention was created under the background of the above-described prior art, and its purpose is to provide a membrane cutting method that prevents defects in an electrode assembly due to thermal deformation of the membrane, and a membrane cutting device used therefor.

[0015] Another technical problem of the present invention is to provide a method for winding a separator that prevents defects that may occur due to electrode particles sticking to the separator.

[0016] 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.

[0017] In order to solve the above problem, the present invention provides a membrane cutting device including: a tension roll that provides tension to a membrane unfolding portion unfolded from an electrode laminate; a gripper that holds the electrode laminate in a state where the electrode laminate is pulled from the tension roll; a cutter that heat-cuts the membrane unfolding portion by lifting and lowering the membrane unfolding portion from an upper side thereof while the membrane unfolding portion is tensioned between the electrode laminate and the tension roll; and a control unit that controls the membrane cutting device such that a first end of the membrane formed on the electrode laminate side moves relative to the cutter in a first direction away from the cutter after lowering and before raising the cutter.

[0018] According to the present invention, thermal deformation of the first end due to an increase in the contact time between the first end and the cutter can be prevented by avoiding the cutter immediately after the separation membrane expansion section is cut.

[0019] It is preferable that the first direction intersects the ascending and descending direction of the cutter. Accordingly, the contact time between the first end and the ascending and descending cutter can be minimized.

[0020] The gripper may be configured to pull the electrode laminate away from the tension roll, thereby allowing the first end to move away from the cutter.

[0021] Alternatively, the gripper may be configured to be movable in the first direction. Accordingly, the first end may also be movable in the first direction relative to the cutter.

[0022] According to one embodiment of the present invention, the gripper is configured to pull the electrode stack, and the separator cutting device may further include a guide portion that guides the first end to move in the first direction while the gripper pulls the electrode stack. At this time, the direction in which the gripper pulls the electrode stack does not have to be a direction away from the cutter, and does not have to include the first direction component. For example, even when the gripper pulls the electrode stack downward while the guide portion supports the separator spreading portion from below, the first end can move in the first direction along the guide portion.

[0023] According to one variation, the cutter may be configured to be movable in a direction opposite to the first direction while in a lowered state. That is, the relative movement between the first end and the cutter may be achieved by the cutter moving relative to the first end.

[0024] According to one embodiment of the present invention, the tension roll may be positioned above the membrane unfolding portion and horizontally spaced from the cutter. Accordingly, when the membrane unfolding portion is cut, the second end may sag due to gravity and move away from the cutter, thereby avoiding thermal deformation due to increased contact time with the cutter.

[0025] According to one variation, the control unit may control the membrane cutting device such that the tension roll moves relative to the cutter in a second direction away from the cutter before the cutter is raised after the cutter is lowered. That is, the second end may avoid contact with the cutter as the tension roll moves away from the cutter.

[0026] It is preferable that the second direction intersects the ascending and descending direction of the cutter. Accordingly, the contact time between the second end and the ascending and descending cutter can be minimized.

[0027] The present invention also provides a membrane cutting method, which sequentially includes a pulling step in which a gripper holds and pulls an electrode laminate to form a membrane expansion portion between the electrode laminate and a tension roll; a cutter lowering step in which a cutter descends from an upper side of the membrane expansion portion and cuts the membrane expansion portion; an avoidance step in which a first end of the membrane formed on the electrode laminate side moves relative to the first direction away from the cutter; and a cutter raising step in which the cutter rises to a position before lowering.

[0028] According to the present invention, thermal deformation of the first end due to an increase in the contact time between the first end and the cutter can be prevented by avoiding the cutter immediately after the separation membrane expansion section is cut.

[0029] It is preferable that the first direction intersects the ascending and descending direction of the cutter. Accordingly, the contact time between the first end and the ascending and descending cutter can be minimized.

[0030] In the above avoidance step, the gripper can pull the electrode laminate away from the tension roll, thereby causing the first end to move away from the cutter.

[0031] Alternatively, in the avoidance step, the gripper may move in the first direction and pull the electrode stack. Accordingly, the first end may also move in the first direction with respect to the cutter.

[0032] According to one embodiment of the present invention, in the avoidance step, the gripper pulls the electrode stack, and accordingly, the first end can move in the first direction along the guide portion. At this time, the direction in which the gripper pulls the electrode stack does not have to be a direction away from the cutter, and does not have to include the first direction component. For example, even when the gripper pulls the electrode stack downward while the guide portion supports the separator expansion portion from below, the first end can move in the first direction along the guide portion.

[0033] According to one variation, in the avoidance step, the cutter can move in a direction opposite to the first direction. That is, the relative movement between the first end and the cutter can be achieved by the cutter moving with respect to the first end.

[0034] According to one variation, the membrane cutting method may further include, between the cutter lowering step and the cutter raising step, a step in which the tension roll moves relative to the cutter in a second direction away from the cutter. That is, the second end may avoid contact with the cutter as the tension roll moves away from the cutter.

[0035] It is preferable that the second direction intersects the ascending and descending direction of the cutter. Accordingly, the contact time between the second end and the ascending and descending cutter can be minimized.

[0036] The present invention also provides a method for winding a separator for finishing an electrode laminate formed by stacking electrodes on each layer of a zigzag-folded separator with the separator, the method comprising: a fixing step in which an end of a separator unfolding portion extending in one width direction from the uppermost layer of the separator stacked directly under the uppermost electrode is fixed to an end fixing portion; a holding step in which an upper mandrel and a lower mandrel extending in the longitudinal direction respectively lift and hold the electrode laminate such that the upper mandrel contacts the uppermost electrode and the lower mandrel contacts the lowermost layer of the separator; a first winding step in which the upper mandrel and the lower mandrel rotate the electrode laminate 360 ​​degrees counterclockwise when viewed so that the extending direction of the separator unfolding portion faces rightward, thereby winding the separator unfolding portion so that it surrounds four sides of the electrode laminate; And, the present invention provides a membrane winding method, including a release step in which the upper mandrel and the lower mandrel escape from the electrode laminate along the longitudinal direction and release the electrode laminate.

[0037] According to the present invention, in the process of winding and finishing the separator on the electrode laminate, the upper mandrel in contact with the uppermost electrode does not contact the separator, thereby preventing contamination of the separator due to electrode particles coming out from the uppermost electrode or the risk of a short circuit caused by the same.

[0038] The membrane winding method according to one embodiment of the present invention may further include, after the first winding step, a second winding step in which the electrode laminate is further rotated by 90 degrees, and thus the membrane unfolding portion is covered again on the side of the electrode laminate.

[0039] At this time, the above-described membrane winding method may further include, after the second winding step, an attachment step in which an end of the membrane expansion unit is released from fixation, and the remaining portion of the membrane expansion unit, covering the side surface of the electrode laminate, is attached to at least a portion of the bottom surface of the electrode laminate. Here, the attachment may include all of adhesion using a binder, fusion, temporary attachment using static electricity, etc.

[0040] In the above attachment step, the separator expansion portion can be adhered to the lower surface of the electrode laminate by brushing. Accordingly, the pouch insertability of the electrode laminate can be improved and the dimensions can be made constant.

[0041] According to one embodiment of the present invention, the membrane winding method may further include, after the gripping release step, a returning step in which the upper mandrel and the lower mandrel return to the same positions as before gripping the electrode laminate. That is, after the membrane winding method is performed and before a new membrane winding process is started, the upper mandrel, which has electrode particles from the uppermost electrode, is placed on the upper side again, so that the bottom surface of the upper mandrel only comes into contact with the uppermost electrode, and the electrode particles may not contaminate the membrane.

[0042] According to one variation, the above membrane winding method may further include, immediately after the first winding step, an attachment step in which an end of the membrane unfolding portion is released from fixation, and the membrane unfolding portion covers four sides of the electrode laminate and attaches the remaining portion to at least a portion of a side surface of the electrode laminate. That is, in this case, the membrane unfolding portion may be attached directly to the side surface rather than covering the side surface of the electrode laminate and then being attached to the bottom surface.

[0043] In the above attachment step, the separator expansion portion can be adhered to the side of the electrode laminate by brushing.

[0044] In the above-described release step, the upper mandrel can escape the electrode laminate along the longitudinal direction after being released from contact with the uppermost electrode. In other words, the upper mandrel can escape the electrode laminate while being spaced apart from the uppermost electrode and without applying a normal force to the surface of the uppermost electrode. Accordingly, the upper mandrel does not experience sliding friction with the uppermost electrode, thereby minimizing the amount of electrode particles adhering to the upper mandrel.

[0045] The above membrane winding method may further include, after the release step, a first particle removal step for removing electrode particles adhering to the lower surface of the upper mandrel. Accordingly, contamination of the separator by electrode particles adhering to the upper mandrel can be more effectively prevented.

[0046] The membrane winding method according to one embodiment of the present invention may further include, before the fixing step, a pulling step in which a gripper holds the electrode laminate up and down and pulls the electrode laminate to form the membrane unfolding portion; and, after the gripping step, a gripper releasing step in which the gripper releases the electrode laminate.

[0047] At this time, according to one embodiment of the present invention, after the gripper release step, the gripper may not grip the electrode stack again. That is, the surface of the gripper that came into contact with the uppermost electrode does not come into contact with the separator, thereby preventing contamination of the separator by electrode particles.

[0048] The above-described membrane winding method may further include, after the gripper release step, a second particle removal step for removing electrode particles adhering to the surface of the gripper. Accordingly, contamination of the separator by electrode particles adhering to the gripper can be more effectively prevented.

[0049] The present invention provides a membrane cutting method in which the end formed by cutting the membrane deployment portion is prevented from thermal deformation by avoiding the cutter immediately after cutting. Specifically, the present invention provides a membrane cutting device and method in which both the first end and the second end of the membrane deployment portion can avoid thermal deformation.

[0050] The present invention can also provide a method for winding a separator in which contamination of the separator and resulting defects are prevented due to contact between the gripper and / or mandrel in frictional contact with the electrode and the separator.

[0051] 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.

[0052] Figure 1 shows the appearance of an electrode laminate formed by completing zigzag stacking.

[0053] Figure 2 shows a state in which an electrode laminate is pulled and a separator expansion portion is formed.

[0054] Figure 3 shows a membrane cutting device.

[0055] Figures 4 to 7 illustrate the process of cutting the membrane expansion section.

[0056] Figure 8 shows the first end of the membrane expansion unit being thermally deformed.

[0057] Fig. 9 shows a membrane winding device.

[0058] Figures 10 to 16 illustrate the process of winding a separator unfolding portion onto an electrode laminate.

[0059] Figure 17 shows a manufacturing process of an electrode assembly according to one embodiment of the present invention.

[0060] Fig. 18 shows a membrane cutting device according to one embodiment of the present invention, and Fig. 19 shows a membrane cutting method according to one embodiment of the present invention.

[0061] Figures 20 to 23 illustrate a cutting process of a membrane expansion unit according to one embodiment of the present invention.

[0062] Fig. 24 shows a membrane winding method according to one embodiment of the present invention, and Fig. 25 shows a membrane winding device according to one embodiment of the present invention.

[0063] Figures 26 to 31 illustrate the winding process of a membrane unfolding unit according to one embodiment of the present invention.

[0064] [Explanation of symbols]

[0065] 1: Electrode laminate

[0066] 10: Membrane

[0067] 10T: Top layer of the membrane

[0068] 100: Membrane deployment section

[0069] 101: Part 1

[0070] 102: Part 2

[0071] 11: First electrode (anode)

[0072] 12: Second electrode (cathode)

[0073] 12T: Top electrode

[0074] 20: Stack Table

[0075] 21: Nip Roll

[0076] 22: Tension roll

[0077] 23: Gripper

[0078] 231: Upper gripper

[0079] 232: Lower gripper

[0080] 24: Cutter

[0081] 251: Guide Department

[0082] 252: End fixing part

[0083] 26: Mandrel

[0084] 261: Upper mandrel

[0085] 262: Lower mandrel

[0086] 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 a detailed description of a known technology related to the present invention is judged to 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.

[0087] 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.

[0088] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0089] Hereinafter, the phrase "any configuration is placed on the "upper (or lower)" side of a component or "on (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] This specification exemplifies a method for manufacturing an electrode assembly. Specifically, the present invention relates to a finishing process for completing an electrode assembly by finishing an electrode laminate with a separator in a method for manufacturing an electrode assembly according to one embodiment of the present invention. The finishing process specifically includes unfolding and cutting a separator, and winding it around an electrode laminate for finishing.

[0094] Hereinafter, a preferred embodiment of the present invention will be described with reference to the attached drawings.

[0095]

[0096] [Electrode assembly manufacturing process and lamination steps]

[0097] Fig. 17 illustrates a manufacturing process of an electrode assembly according to one embodiment of the present invention. Referring to this, the manufacturing process of an electrode assembly according to one embodiment of the present invention includes a lamination step (S1) of forming an electrode laminate by laminating a separator and an electrode, a cutting step (S2) of unfolding the electrode laminate by pulling the separator and then cutting it, and a winding step (S3) of winding the electrode laminate with the separator.

[0098] Figure 1 shows a state in which an electrode laminate is formed by completing zigzag stacking. Referring to this, in the stacking step (S1) according to one embodiment of the present invention, the electrode laminate (1) is formed by alternately stacking a first electrode (11) and a second electrode (12) on each layer of a separator (10) that is continuously supplied from a nip roll (21) and folded in a zigzag manner on a stack table (20). There are various methods for zigzag stacking to form such a structure, but the present invention does not discriminate between them.

[0099] The first electrode (11) and the second electrode (12) may be one or the other of an anode and a cathode, respectively. According to one embodiment of the present invention, the first electrode (11) is an anode and the second electrode (12) is a cathode.

[0100] According to one embodiment of the present invention, the second electrode (12) is provided by one more than the first electrode (11). Accordingly, the total number of electrodes (11, 12) becomes an odd number, and the uppermost and lowermost layers are composed of the second electrode (12).

[0101]

[0102] [Separator cutting device and membrane cutting method]

[0103] Referring again to FIG. 17, the cutting step (S2) according to another embodiment of the present invention may be performed using the membrane cutting method described below.

[0104] Fig. 18 shows a membrane cutting device according to one embodiment of the present invention. Referring to this, the membrane cutting device according to one embodiment of the present invention includes: a tension roll (22) that provides tension to a membrane unfolding portion (100) unfolded from the electrode laminate (1); a gripper (23) that holds the electrode laminate (1) in a state where it is pulled from the tension roll (22); a cutter (24) that heat-cuts the membrane unfolding portion (100) by moving up and down from the upper side of the membrane unfolding portion (100) while the membrane unfolding portion (100) is tensioned between the electrode laminate (1) and the tension roll (22); and a control unit (not shown) that controls the membrane cutting device such that a first end portion (101) of the membrane formed on the electrode laminate (1) moves relative to the cutter (24) in a first direction away from the cutter (24) after the cutter (24) descends and before the cutter (24) ascends.

[0105] The above separator (10) can be continuously supplied through a nip roll (21). At this time, the tension roll (22) may be positioned between the nip roll (21) and the electrode laminate (1) along the traveling direction of the separator (10), or may be the nip roll (21) itself.

[0106] The above gripper (23) is formed as a pair including an upper gripper (231) and a lower gripper (232), and can lift and hold the electrode laminate (1) from both the upper and lower sides.

[0107] Fig. 19 shows a membrane cutting method according to one embodiment of the present invention, and Figs. 20 to 23 show a cutting process of a membrane expansion unit according to one embodiment of the present invention.

[0108] Referring to FIGS. 20 and 21, the membrane cutting method according to one embodiment of the present invention includes a pulling step (S21) in which the gripper (23) grasps and pulls the electrode laminate (1) to form the membrane expansion part (100) between the electrode laminate (1) and the tension roll (22), and a cutter lowering step (S22) in which the cutter (24) descends from the upper side of the membrane expansion part (100) to cut the membrane expansion part (100).

[0109] At this time, a first end (101) is formed on the electrode laminate (1) side of the cut separator expansion portion (100), and a second end (102) is formed on the nip roll (21) side.

[0110] Referring to FIGS. 22 and 23, a membrane cutting method according to one embodiment of the present invention sequentially includes an avoidance step (S23) in which the first end portion (101) of the membrane formed on the electrode laminate (1) side moves relative to the cutter (24) in the first direction away from the cutter (24), and a cutter elevation step (S24) in which the cutter (24) rises to a position before it is lowered.

[0111] According to one embodiment of the present invention, by avoiding the first end (101) from the cutter (24) before the cutter (24) rises, the first end (101) of the separation membrane can be prevented from being excessively heated and thermally deformed during the process of the cutter (24) rising back to its original position.

[0112] It is preferable that the first direction intersects the ascending and descending direction of the cutter (24). Accordingly, the contact time between the first end (101) and the ascending and descending cutter (24) can be minimized. If the first direction is parallel to the ascending and descending direction of the cutter (24), it may be difficult for the first end (101) to avoid contact with the cutter (24).

[0113] Referring again to FIG. 18, the gripper (23) can be configured to pull the electrode laminate (1) away from the tension roll (22).

[0114] Alternatively, the gripper (23) may be configured to be movable in the first direction. Accordingly, the first end (101) may also be movable in the first direction with respect to the cutter (24).

[0115] According to one embodiment of the present invention, the gripper (23) is configured to be able to pull the electrode laminate (1), and the separator cutting device may additionally include a guide portion (251) that guides the first end (101) to move in the first direction while the gripper (23) pulls the electrode laminate (1).

[0116] Referring back to FIGS. 21 and 22 together with FIG. 18, in the avoidance step (S23) according to one embodiment of the present invention, the gripper (23) pulls the electrode stack (1), and accordingly, the first end (101) can move in the first direction along the guide portion (251). At this time, the direction in which the gripper (23) pulls the electrode stack (1) does not have to be a direction away from the cutter (24), and does not have to include the first direction component. For example, even when the gripper (23) pulls the electrode stack (1) downward while the guide portion (251) supports the separator expansion portion (100) from below, the first end (101) can move in the first direction along the guide portion (251).

[0117] According to one variation, according to one variation, the cutter (24) may be configured to be movable in a direction opposite to the first direction in a lowered state, and in the avoidance step (S23), the cutter (24) may be movable in a direction opposite to the first direction. That is, the relative movement between the first end (101) and the cutter (24) may be achieved by the cutter (24) moving with respect to the first end (101).

[0118] Referring back to FIG. 18, the tension roll (22) according to one embodiment of the present invention may be positioned above the membrane expansion unit (100) and horizontally spaced apart from the cutter (24). Accordingly, as shown in FIG. 22, at the moment the membrane expansion unit (100) is cut, the second end (102) may sag due to gravity and move away from the cutter (24), thereby avoiding thermal deformation due to increased contact time with the cutter (24).

[0119] According to one variation, the membrane cutting method may further include, between the cutter lowering step (S22) and the cutter raising step (S24), a step of relative movement of the tension roll (22) in a second direction away from the cutter (24), and the control unit may be configured to control the membrane cutting device such that the tension roll (22) relative movement is made in the second direction away from the cutter (24). That is, the second end (102) may avoid contact with the cutter (24) as the tension roll (22) moves away from the cutter (24).

[0120] At this time, it is preferable that the second direction intersects the ascending and descending direction of the cutter (24). Accordingly, the contact time between the second end (102) and the ascending and descending cutter (24) can be minimized.

[0121]

[0122] [Separator winding device and membrane winding method]

[0123] Referring again to FIG. 17, the winding step (S3) according to another embodiment of the present invention may be performed using the membrane winding method described below.

[0124] Fig. 24 illustrates a membrane winding method according to one embodiment of the present invention, and Fig. 25 illustrates a membrane winding device according to one embodiment of the present invention. Referring to these drawings, the membrane winding device according to one embodiment of the present invention includes a gripper (23) for holding the electrode laminate (1), an end fixing part (252) for holding an end of the membrane expansion part (100), and a mandrel (26) configured to hold and rotate the electrode laminate (1).

[0125] Figures 26 to 31 illustrate the winding process of a membrane unfolding unit according to one embodiment of the present invention.

[0126] Referring to FIG. 26, the membrane winding method according to one embodiment of the present invention includes a fixing step (S31) in which an end of the membrane expansion unit (100) extending in one width direction is fixed to the end fixing unit (252). In the fixing step (S31), the membrane expansion unit (100) can be appropriately tensioned and maintained taut between the end fixing unit (252) and the electrode laminate (1).

[0127] In the above fixing step (S31), the electrode laminate (1) may be held vertically by the gripper (23). At this time, the upper gripper (231) constituting the gripper (23) may contact the top electrode (12T). Accordingly, electrode particles may be deposited on the lower surface of the upper gripper (231).

[0128] Referring to FIG. 27, the membrane winding method according to one embodiment of the present invention includes a holding step (S32) of lifting and holding the electrode laminate (1) such that the upper mandrel (261) and the lower mandrel (262), each extending in the longitudinal direction, are in contact with the uppermost electrode (12T) and the lower mandrel (262) is in contact with the lowermost layer of the membrane.

[0129] After the above gripping step (S32) is performed, the gripper (23) can release the electrode laminate (1). According to one embodiment of the present invention, the gripper (23) does not grip the electrode laminate (1) again until the subsequent winding process is completed. Accordingly, there is no concern that electrode particles stuck to the lower surface of the upper gripper (231) will contaminate the separator (10).

[0130] Referring to FIGS. 27 and 28, the membrane winding method according to one embodiment of the present invention includes a first winding step (S33) in which the upper mandrel (261) and the lower mandrel (262) rotate the electrode stack (1) 360 degrees counterclockwise when viewed so that the extension direction of the membrane unfolding portion (100) faces right, thereby winding the membrane unfolding portion (100) to surround four sides of the electrode stack (1).

[0131] At this time, the four sides of the electrode laminate (1) can be finished at once without the process of releasing and then re-gripping the electrode laminate (1) by the mandrel (26) and the gripper (23). Accordingly, there is no concern that electrode particles adhering to the mandrel (26) and / or the gripper (23) will contaminate the separator (10).

[0132] Referring to FIG. 29, the membrane winding method according to one embodiment of the present invention may additionally include, after the first winding step (S33), a second winding step (S34) in which the electrode laminate (1) is further rotated by 90 degrees, and thus the membrane unfolding part (100) covers the side of the electrode laminate (1) again.

[0133] The above-described membrane winding method may further include, after the second winding step (S34), an attachment step (S35) in which an end of the membrane expansion unit (100) is released from fixation, and the membrane expansion unit (100) covers the side surface of the electrode stack (1) and attaches the remaining portion to at least a portion of the bottom surface of the electrode stack (1).

[0134] In the above attachment step (S35), the separator expansion portion (100) can be adhered to the lower surface of the electrode laminate (1) by brushing. Accordingly, the pouch insertability of the electrode laminate (1) can be improved and the dimensions can be made constant.

[0135] According to one variation, the above membrane winding method may further include, immediately after the first winding step (S33), an attachment step (S35) in which an end of the membrane unfolding part (100) is released from fixation, the membrane unfolding part (100) covers four sides of the electrode stack (1), and the remaining part is attached to at least a portion of a side surface of the electrode stack (1). That is, in this case, the membrane unfolding part (100) may be attached directly to the side surface, rather than covering the side surface of the electrode stack (1) and then being attached to the bottom surface.

[0136] In the above attachment step (S35), the separator expansion portion (100) can be attached to the side of the electrode laminate (1) by brushing.

[0137] Referring to FIG. 31, the membrane winding method according to one embodiment of the present invention includes a grip release step (S36) in which the upper mandrel (261) and the lower mandrel (262) escape from the electrode laminate (1) along the longitudinal direction and the electrode laminate (1) is released.

[0138] According to one embodiment of the present invention, after the mandrel (26) releases the electrode laminate (1), it does not grip the electrode laminate (1) again. Accordingly, since the upper mandrel (261) in contact with the uppermost electrode (12T) does not contact the separator (10), contamination of the separator (10) due to electrode particles coming out of the uppermost electrode (12T) or the risk of a short circuit caused by this can be prevented.

[0139] At this time, in the release step (S36), the upper mandrel (261) can escape the electrode laminate (1) along the longitudinal direction after being released from contact with the uppermost electrode (12T). In other words, the upper mandrel (261) can escape the electrode laminate (1) while being spaced apart from the uppermost electrode (12T) and without applying a normal force to the surface of the uppermost electrode (12T). Accordingly, the upper mandrel (261) does not experience sliding friction with the uppermost electrode (12T), thereby minimizing the amount of electrode particles adhering to the upper mandrel (261).

[0140] Referring back to FIG. 24, the membrane winding method according to one embodiment of the present invention may further include, after the grip release step (S36), a return step (S37) in which the upper mandrel (261) and the lower mandrel (262) return to the same positions as before gripping the electrode stack (1). That is, after the membrane winding method is performed and before a new membrane winding process is started, the upper mandrel (261) with electrode particles from the uppermost electrode (12T) is placed again on the upper side, so that the bottom surface of the upper mandrel (261) only comes into contact with the uppermost electrode (12T), and the electrode particles may not contaminate the membrane (10).

[0141] The above membrane winding method may additionally include, after the release step (S36), a first particle removal step (S38) for removing electrode particles adhering to the lower surface of the upper mandrel (261). Accordingly, contamination of the separator (10) by electrode particles adhering to the upper mandrel (261) can be more effectively prevented.

[0142] The above-described separator winding method may additionally include a second particle removal step (S39) of removing electrode particles adhering to the surface of the gripper (23) after the gripper releases the electrode laminate (1) (S32). Accordingly, contamination of the separator (10) by electrode particles adhering to the gripper (23) can be more effectively prevented.

[0143] 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.

[0144] 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. In a membrane winding method for finishing an electrode laminate formed by stacking electrodes on each layer of a separator folded in a zigzag pattern with the separator, A fixing step in which an end of a membrane expansion portion extending in one direction in the width direction from the uppermost layer of the membrane laminated directly under the uppermost electrode is fixed to an end fixing portion; A gripping step of lifting and gripping the electrode stack so that the upper mandrel and the lower mandrel, each extending in the longitudinal direction, contact the upper electrode layer and the lower mandrel contact the lowermost layer of the separator; A first winding step in which the upper mandrel and the lower mandrel rotate the electrode laminate 360 ​​degrees counterclockwise when the extension direction of the separator unfolding portion is viewed to the right, thereby winding the separator unfolding portion to surround four sides of the electrode laminate; and A membrane winding method, comprising a release step in which the upper mandrel and the lower mandrel escape from the electrode laminate along the longitudinal direction and release the electrode laminate.

2. In claim 1, A membrane winding method, further comprising a second winding step in which, after the first winding step, the electrode laminate is further rotated by 90 degrees, thereby covering the side of the electrode laminate again by the membrane unfolding portion.

3. In claim 2, A membrane winding method, further comprising an attachment step in which, after the second winding step, an end of the membrane unfolding section is released from fixation, and the membrane unfolding section covers the side surface of the electrode laminate and attaches the remaining portion to at least a portion of the bottom surface of the electrode laminate.

4. In claim 3, A method for winding a separator, wherein in the above attachment step, the separator unfolding portion is brushed so as to adhere to the lower surface of the electrode laminate.

5. In claim 2, A membrane winding method, further comprising, after the above-mentioned release step, a return step in which the upper mandrel and the lower mandrel return to the same position as before the electrode laminate was gripped.

6. In claim 1, A membrane winding method, which further comprises an attachment step in which, immediately after the first winding step, an end of the membrane unfolding section is released from fixation, the membrane unfolding section covers four sides of the electrode laminate, and the remaining portion is attached to at least a portion of a side surface of the electrode laminate.

7. In claim 6, A method for winding a separator, wherein in the above attachment step, the separator unfolding portion is brushed so as to adhere to the side of the electrode laminate.

8. In claim 1, A membrane winding method, wherein in the above-mentioned release step, the upper mandrel is released from contact with the uppermost electrode and then escapes the electrode laminate along the longitudinal direction.

9. In claim 1, A membrane winding method, further comprising a first particle removal step for removing electrode particles adhering to the lower surface of the upper mandrel after the above-mentioned phage release step.

10. In claim 1, Before the above fixing step, a pulling step in which the gripper pulls the electrode stack up and down to form the separator unfolding portion; and A membrane winding method, further comprising, after the gripping step, a gripper releasing step in which the gripper releases the electrode laminate.

11. In claim 10, A method for winding a separator, characterized in that the gripper does not grip the electrode laminate again after the gripper release step.

12. In claim 10, A membrane winding method, further comprising a second particle removal step for removing electrode particles adhering to the surface of the gripper after the gripper release step.

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