Induction heating device, method for manufacturing electrode assembly including the same, and device for manufacturing electrode assembly including the same

Abstract

In order to solve the problems caused by inconsistent adhesive strength, the present invention provides an induction heating device including at least one induction heating plate that inductively heats an electrode assembly and an induction heating coil built into the induction heating plate, wherein the induction heating coil includes: a first portion of the induction heating coil forming a winding, serpentine pattern; and a second portion of the induction heating coil extending around the induction heating plate; a method for manufacturing an electrode assembly including the induction heating device; and an apparatus for manufacturing an electrode assembly including the induction heating device.

Description

[Technical Field]

[0001] The present invention claims the benefit of the filing date of Korean Patent Application No. 10-2023-0058195 filed with the Korean Intellectual Property Office on May 4, 2023, and Korean Patent Application No. 10-2024-0047755 filed with the Korean Intellectual Property Office on April 9, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an induction heating device, a method for manufacturing an electrode assembly including the induction heating device, and an apparatus for manufacturing an electrode assembly including the induction heating device. [Background technology]

[0003] Secondary batteries, unlike primary batteries, are rechargeable and have the potential to be small and have large capacities. As technological development and demand for mobile devices increases, the demand for secondary batteries as an energy source is rapidly increasing.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries depending on the shape of the battery case. The electrode assembly attached to the inside of the battery case in a secondary battery is a power generating element that can be charged and discharged as a laminated structure of electrodes and a separator.

[0005] Electrode assemblies can be broadly classified into a jelly-roll type in which a sheet-like positive electrode and negative electrode, each coated with an active material, are wound up with a separator interposed between them; a stack type in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them; and a stack-and-fold type in which stack-type unit cells are wound up with a long separator film.

[0006] In the stack-and-fold type electrode assembly, the separator is folded in a zigzag pattern and stacked, and a positive or negative electrode is inserted between the folded separators, thereby manufacturing an electrode assembly in which the positive electrode, separator, and negative electrode are stacked.

[0007] During this process, heat and pressure are applied to the stack of the positive electrode, separator, and negative electrode in order to bond the electrodes and separator together.

[0008] However, applying heat and pressure to the laminate to bond the electrodes (positive and negative electrodes) and the separator within the laminate requires a long time and a lot of energy.

[0009] Furthermore, when heat and pressure are applied to the laminate, the heat and pressure cannot be applied uniformly regardless of the stacking positions of the electrodes and separator due to differences in stacking positions (stacking height) of the electrodes and separator within the laminate, which results in an inconsistent adhesive strength between the separator and the electrodes.

[0010] As a result, there is a problem in that the performance of the electrode assembly becomes non-uniform.

[0011] To solve this problem, a method of inductively heating a laminate including electrodes and a separator was considered, but there was a problem in that it was difficult to ensure the desired level of temperature uniformity due to the shape of the coil used for induction heating.

[0012] Therefore, research into the shape of the induction heating coil to ensure temperature uniformity is required. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Korean Patent Publication No. 10-2013-0132230 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention aims to provide an induction heating device that solves problems caused by uneven adhesive strength, a method for manufacturing an electrode assembly including the same, and an apparatus for manufacturing an electrode assembly including the same. [Means for solving the problem]

[0015] One embodiment of the present invention provides an induction heating device including at least one induction heating plate having main surfaces along a longitudinal direction and a width direction and configured to inductively heat an electrode assembly, and an induction heating coil incorporated in the induction heating plate, wherein the induction heating coil includes: a first portion of the induction heating coil forming a meandering pattern to a first depth in a thickness direction perpendicular to the main surface of the induction heating plate; and a second portion of the induction heating coil extending around the induction heating plate to a second depth in the thickness direction perpendicular to the main surface of the induction heating plate.

[0016] One embodiment of the present invention provides a method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, the method including: a stacking step of stacking a laminate including the first electrode, the separator, and the second electrode on a stack table; an induction heating step of inductively heating the laminate using an induction heating device; and a heat pressing step of heating and pressing the induction-heated laminate.

[0017] One embodiment of the present invention provides an electrode assembly manufacturing apparatus for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, the apparatus including: a stack table on which the first electrode, the separator, and the second electrode are stacked to form a laminate including the first electrode, the separator, and the second electrode; a heat press unit that heats and pressurizes the laminate; and an induction heating unit that inductively heats the laminate before heating and pressurizing the laminate in the heat press unit, wherein the induction heating unit is the induction heating device. [Effects of the Invention]

[0018] The induction heating device according to the embodiment of the present application can uniformly transfer heat during the process of manufacturing an electrode assembly, thereby reducing temperature variations.

[0019] The induction heating device according to the embodiments of the present application can be applied to electrode assemblies of various sizes, which provides process advantages.

[0020] The electrode assembly manufacturing method and electrode assembly manufacturing apparatus according to the embodiments of the present application can shorten the time required to manufacture the electrode assembly.

[0021] The electrode assembly manufacturing method and electrode assembly manufacturing apparatus according to the embodiments of the present application can easily adjust the temperature of the electrodes to a specific temperature range and reduce the temperature deviation between the electrodes, thereby providing an electrode assembly with uniform performance.

[0022] The electrode assembly according to the embodiment of the present application has the advantage that the variation in separator permeability depending on the position is small and the performance is uniform. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram illustrating an example of a conventional induction heating device. [Figure 2] 1 is a diagram showing a transfer pattern of an electrode assembly manufactured using a conventional induction heating device. [Figure 3] 1 is an exemplary diagram illustrating an induction heating device according to one embodiment of the present invention. [Figure 4] 1 is an exemplary diagram illustrating an induction heating device according to one embodiment of the present invention. [Figure 5] 10A and 10B are diagrams showing transfer patterns and adhesive force patterns of an electrode assembly manufactured using an induction heating apparatus according to one embodiment of the present invention. [Figure 6] 1 is a plan view illustrating an example of an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 7] 1 is a front view showing the concept of an electrode assembly manufacturing apparatus according to an embodiment of the present invention; [Figure 8] 1 is a cross-sectional view illustrating an example of a conventional electrode assembly. [Figure 9] 1A to 1C are diagrams illustrating an example of a process using a manufacturing method or apparatus for an electrode assembly according to an embodiment of the present invention; [Figure 10] 1A to 1C are diagrams illustrating an example of a process using a manufacturing method or apparatus for an electrode assembly according to an embodiment of the present invention; [Figure 11] FIG. 1(a) is a perspective view showing a first heat press unit 50 according to an embodiment of the present invention, and FIG. 1(b) is a perspective view showing a second heat press unit 60 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0025] In this specification, when a part is said to "comprise" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0026] In one embodiment of the present invention, the electrode assembly may be stacked such that the first electrodes and the second electrodes are alternately arranged between the folded separators.

[0027] In this specification, stacking the first and second electrodes alternately between the folded separator is referred to as zigzag stacking.

[0028] In this case, to more specifically describe the alternate arrangement of the first and second electrodes between the folded separators, the folded separator may refer to a separator in which the separators are stacked in a zigzag pattern. More specifically, the separators are folded alternately from the left side of the stacking axis to the right side of the stacking axis and stacked in a zigzag pattern. The term "stack axis" refers to an imaginary axis that is parallel to the direction in which the first electrodes, separators, and second electrodes are stacked and passes through the center of the stack of electrodes and separators.

[0029] In other words, the fact that the first electrodes and the second electrodes are alternately arranged between the separation membranes means that the separation membranes are stacked in a zigzag pattern in the direction of the stacking axis, and one first electrode and one second electrode are alternately inserted into the spaces (between the separation membranes) generated by the overlapping separation membranes.

[0030] <Induction heating device> An embodiment of the present invention provides an induction heating device including an induction heating coil. The induction heating device according to an embodiment of the present invention may include an induction heating coil and an induction heating plate.

[0031] The induction heating plate according to the present invention has main surfaces along the longitudinal and width directions, and is characterized by being capable of induction heating an electrode assembly.

[0032] The induction heating device according to the present invention can be characterized in that, when the induction heating plate is viewed from above, a first portion of the induction heating coil has a serpentine pattern at a first depth in a thickness direction perpendicular to a main surface of the induction heating plate, and a second portion of the induction heating coil extends around the induction heating plate at a second depth in a thickness direction perpendicular to the main surface of the induction heating plate.

[0033] In one embodiment of the present invention, the main surface of the induction heating plate may be arranged to face the electrode assembly to be induction heated, and the first and second portions of the induction heating coil may extend in a direction parallel to the main surface of the induction heating plate.

[0034] In one embodiment of the present invention, the "first depth" or "second depth" refers to a predetermined depth that is a certain distance away from the main surface of the induction heating plate in the thickness direction (or depth direction) perpendicular to the main surface. The first depth and the second depth may be the same or different. Referring to FIG. 3(d), the first portion 191a of the induction heating coil is spaced a distance t1 from the main surface (not shown) of the induction heating plate 192 in the thickness direction perpendicular to the main surface, and this distance t1 can be referred to as the first depth. The second portion 191b of the induction heating coil is spaced a distance t2 from the main surface (not shown) of the induction heating plate 192 in the thickness direction perpendicular to the main surface, and this distance t2 can be referred to as the second depth. Referring to FIG. 3(c) or 3(d), t1 and t2 are different from each other. Although not shown, referring to FIG. 4(c), t1 and t2 are the same.

[0035] In one embodiment of the present invention, the first depth and the second depth may be different from each other, and the induction heating device may further include a third portion of the induction heating coil connecting the first portion of the induction heating coil and the second portion of the induction heating coil. That is, the first portion of the induction heating coil may be disposed on a different plane from the second portion of the induction heating coil and connected to each other by the third portion of the induction heating coil. In this case, the first portion of the induction heating coil and the second portion of the induction heating coil may be integrally formed by being connected by the third portion of the induction heating coil. This feature allows for optimized induction heating of the electrode assembly. Optimizing induction heating means that the electrode assembly can be heated uniformly without generating a transfer pattern, i.e., a mark, which occurs when a specific portion of the electrode assembly is heated relatively more.

[0036] An induction heating apparatus according to one embodiment of the present invention may be used in the manufacture of electrode assemblies.

[0037] In one embodiment of the present invention, the at least one induction heating plate may include a first induction heating plate on which an electrode assembly including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode is placed, and a second induction heating plate disposed opposite the first induction heating plate. In this case, the first induction heating plate may be a lower heating plate, and the second induction heating plate may be an upper induction heating plate.

[0038] In the induction heating device according to one embodiment of the present invention, at least one of the first induction heating plate and the second induction heating plate may have the induction heating coil built in. Alternatively, both the first induction heating plate and the second induction heating plate may have the induction heating coil built in.

[0039] In another embodiment of the present invention, the first depth and the second depth may be the same, meaning that the second portion of the induction heating coil is disposed on the same plane as the first portion of the induction heating coil. In this case, the second portion of the induction heating coil can avoid short-circuiting with the first portion of the induction heating coil. That is, the second portion can cross the first portion while avoiding physical contact with the first portion on the same plane.

[0040] In one embodiment of the present invention, when the second portion of the induction heating coil is arranged on the same plane as the first portion of the induction heating coil, the first portion and the second portion are in a continuous form, i.e., the first portion and the second portion are connected.

[0041] In one embodiment of the present invention, the induction heating plate may further include a third portion of the induction heating coil connecting the first portion and the second portion of the induction heating coil, and when viewed in a thickness direction perpendicular to a main surface of the induction heating plate, the second portion of the induction heating coil may cross the first portion of the induction heating coil so as to overlap an apex formed on the first portion of the induction heating coil. That is, the induction heating coil may have a two-layer structure consisting of an upper layer and a lower layer. Here, the upper layer may correspond to the layer on which the first portion of the induction heating coil is disposed, and the lower layer may correspond to the layer on which the second portion of the induction heating coil is disposed.

[0042] One embodiment of the present invention provides an induction heating device including: a lower induction heating plate on one surface of which a heating target is placed; an upper induction heating plate having a surface opposite to the one surface of the lower induction heating plate; and an induction heating coil provided inside at least one of the lower induction heating plate and the upper induction heating plate, wherein the induction heating coil has a two-layer structure consisting of an upper layer and a lower layer, and the upper layer of the induction heating coil has a winding, serpentine pattern when viewed from the direction of one surface of the lower induction heating plate.

[0043] In one embodiment of the present invention, the third portion of the induction heating coil may be arranged to extend in the height direction (or thickness direction) of the induction heating plate so as to connect the first portion of the induction heating coil and the second portion of the induction heating coil, which are arranged on different planes. That is, the third portion of the induction heating coil may extend in the height direction of the induction heating plate. Of course, the third portion of the induction heating coil may be arranged vertically, which is the height direction of the induction heating plate, or may extend diagonally.

[0044] The lower layer on which the second portion of the induction heating coil is disposed may be horizontal with the upper layer on which the first portion of the induction heating coil is disposed, and the upper layer and the lower layer of the induction heating coil may be spaced apart. That is, even in a two-layer structure, the first portion of the induction heating coil and the second portion of the induction heating coil are disposed on different planes so as not to short-circuit each other.

[0045] In one embodiment of the present invention, the length of the third portion may be 0 mm or more, more specifically, 0 mm or more and 40 mm or less, but the upper limit of the length may vary depending on the size of the induction heating plate.

[0046] In this case, the third portion having a length of 0 mm means that the first and second portions of the induction heating coil are arranged on the same plane, and the third portion having a length greater than 0 mm means that the first and second portions of the induction heating coil have a two-layer structure.

[0047] In one embodiment of the present invention, the first and second portions of the induction heating coil may be connected. In this case, in the case of a two-layer structure, the third portion of the induction heating coil may be further included. For example, in the case of a two-layer structure, the first portion of the induction heating coil has a meandering pattern from the start point of the first portion to the end point. Then, at the end of the first portion of the induction heating coil, the induction heating coil extends perpendicularly to the direction of the second portion of the induction heating coil. In this case, the perpendicularly extending coil represents the third portion of the induction heating coil. At the end of the third portion of the induction heating coil, the induction heating coil may extend in the direction of the start point of the first portion of the induction heating coil, thereby forming the second portion of the induction heating coil.

[0048] In one embodiment of the present invention, the second portion of the induction heating coil may extend around the induction heating plate to a second depth in a thickness direction perpendicular to the main surface of the induction heating plate, and may cross the first portion of the induction heating coil so as to overlap with an apex formed in the first portion of the induction heating coil, or may surround an edge of the first portion of the induction heating coil.

[0049] The shape of the second portion of the induction heating coil is not limited as long as it can cross the first portion of the induction heating coil so as to overlap the apex formed on the first portion of the induction heating coil. However, in the case of a double-layer structure, a linear shape is preferred because it can reduce process costs.

[0050] Furthermore, if the induction heating coil does not have a two-layer structure, the third portion of the induction heating coil is not necessary. Furthermore, the shape of the second portion of the induction heating coil is not limited as long as it is not short-circuited with the first portion of the induction heating coil and crosses the first portion of the induction heating coil so as to overlap with the vertex formed on the first portion of the induction heating coil when viewed in the thickness direction perpendicular to the main surface of the induction heating plate. However, the more linear portions of the second portion of the induction heating coil, the more preferable it is because it reduces processing costs.

[0051] Here, the second portion of the induction heating coil is disposed so as to cross the first portion of the induction heating coil, but crossing does not necessarily mean that it must overlap with the first portion of the induction heating coil when viewed in the thickness direction perpendicular to the main surface of the induction heating plate. That is, when viewed in the thickness direction perpendicular to the main surface of the induction heating plate, the second portion of the induction heating coil can cross so as to overlap with the first portion of the induction heating coil, but it can also cross so as to surround the outer periphery of the first portion of the induction heating coil. That is, they may not overlap when viewed from a plane.

[0052] In one embodiment of the present invention, when viewed in a thickness direction perpendicular to a main surface of the induction heating plate, the second portion of the induction heating coil may surround an edge of the first portion of the induction heating coil.

[0053] In one embodiment of the present invention, the first portion of the induction heating coil and the second portion of the induction heating coil may form at least one closed curve when viewed from a thickness direction perpendicular to a main surface of the induction heating plate.

[0054] In one embodiment of the present invention, the at least one induction heating plate may include a non-conductive material, i.e., in one embodiment of the present invention, at least one of the first induction heating plate and the second induction heating plate may include a non-conductive material.

[0055] The induction heating plate may include an AC generator that supplies AC to the induction heating coil and functions to protect the induction heating coil. The reason for using a non-conductive material for the induction heating plate is to prevent the induction current from the induction heating coil from being generated in the induction heating plate.

[0056] The induction heating plate may be a mold made of a non-conductive material, which may be, but is not limited to, epoxy.

[0057] The induction heating coil and the induction heating plate may be a single set.

[0058] The induction heating unit may include an AC generator, but is not limited thereto, and any means that can generate an electromagnetic induction phenomenon in the induction heating coil may be used.

[0059] In one embodiment of the present invention, the first portion of the induction heating coil may move back and forth in the width direction of the induction heating plate while advancing in the length direction of the induction heating plate to form a serpentine pattern.

[0060] In other words, the first portion of the induction heating coil may be embedded in the induction heating plate and have a meandering pattern that moves back and forth in a zigzag pattern in the width direction of the induction heating plate while progressing in the longitudinal direction of the induction heating plate. The meandering pattern may have a shape in which, based on a central axis in the longitudinal direction, semi-elliptical shapes having a long radius in the direction perpendicular to the central axis, i.e., in the width direction of the heating plate, and a short radius along the direction of progression of the central axis, i.e., the longitudinal direction of the induction heating plate, are alternately arranged in succession. The central axis refers to a straight line passing through the center of the meandering pattern in the direction in which the meandering pattern progresses.

[0061] In one embodiment of the present invention, the first portion of the induction heating coil may be semi-elliptical, moving back and forth in the width direction of the induction heating plate, and the semi-elliptical shape may have a longer radius in the width direction of the induction heating plate and a shorter radius in the longitudinal direction of the induction heating plate, the longer radius being 50 mm or more and 80 mm or less, and the shorter radius being 10 mm or more and 40 mm or less.

[0062] In one embodiment of the present invention, the semi-elliptical shapes may be periodically arranged along the central axis, and the period of the coil may be 10 mm or more and 30 mm or less, preferably 10 mm or more and 25 mm or less, and more preferably 10 mm or more and 25 mm or less.

[0063] If the above conditions are satisfied, the efficiency of induction heating can be further improved.

[0064] FIG. 1 illustrates an example of a conventional induction heating device. Referring to FIG. 1, the conventional induction heating device 90 may include an induction heating coil 91 and an induction heating plate 92. More specifically, induction heating coils 91a and 91b may be built into induction heating plates 92a and 92b. The conventional induction heating device 90 may include a U-shaped induction heating coil 91. The induction heating coils 91a and 91b may be configured to face each other, and the specific arrangement of the induction heating coil 91 may be, but is not limited to, that shown in FIG. 1. When an alternating current is applied to the induction heating coil 91, an induction current is generated in a metallic electrode in the laminate, and the electrode is heated by the induction current.

[0065] When using a conventional U-shaped induction heating coil, as shown in Figure 2, the heat transferred to the induction heating coil varies greatly depending on the position.

[0066] Specifically, in the full-width cross-section of the cell in Figure 2, the dark shaded areas extending from the lower left and upper right edges to the center indicate a state in which heat spreads from the area in contact with the induction heating coil, resulting in a rise in temperature. In the full-width cross-section of the cell in Figure 2, the dark shaded areas at the upper left and lower right edges indicate areas where the heat does not reach and the temperature has dropped. As such, because the difference in heat transfer varies depending on the position, it was confirmed that a specific transfer pattern appears, as shown in the transfer pattern diagram in Figure 2.

[0067] Figures 3 and 4 show an induction heating device 190 according to the present invention. Figure 3 is a diagram illustrating an example in which the first portion of the induction heating coil and the second portion of the induction heating coil have a two-layer structure, and Figure 4 is a diagram illustrating an example in which the first portion of the induction heating coil and the second portion of the induction heating coil are arranged on the same plane.

[0068] Fig. 3(a) shows the shape of the induction heating coil when the induction heating plate 192 is viewed from above. Fig. 3(b) is a perspective view of the induction heating coil built into the induction heating plate 192. Fig. 3(c) shows the shape of the induction heating coil when the induction heating plate 192 is viewed in cross section.

[0069] 3(b), the induction heating coil may be composed of three portions. The induction coil 191 may include a first portion 191a of the induction heating coil that reciprocates in a zigzag pattern in the width direction of the induction heating plate 192, a second portion 191b of the induction heating coil that crosses the first portion 191a of the induction heating coil, and a third portion 191c of the induction heating coil that connects the first portion 191a of the induction heating coil and the second portion 191b of the induction heating coil to each other.

[0070] Assuming that the first portion 191a of the induction heating coil is arranged on a first plane located at a first depth in the thickness direction perpendicular to the main surface of the induction heating plate 192, the second portion 191b of the induction heating coil may be arranged on a plane different from the first plane. This is to prevent a short circuit from occurring when the second portion 191b of the induction heating coil crosses the first portion 191a of the induction heating coil.

[0071] Therefore, the third portion 191c of the induction heating coil may extend in the depth direction (thickness direction) of the induction heating plate, i.e., in the z-axis direction, to connect between the first portion 191a of the induction heating coil and the second portion 191b of the induction heating coil.

[0072] In other words, the induction heating coil 191 may have a two-layer structure, and the two layers may be integrally formed by connecting them with the third portion 191c of the induction heating coil.

[0073] Referring to (b) of Figure 3, assuming that the first portion 191a of the induction heating coil is arranged in the upper layer (layer 2) and the second portion 191b of the induction heating coil is arranged in the lower layer (layer 1), the second portion 191b of the induction heating coil can surround the edge of the first portion 191a of the induction heating coil in the lower layer.

[0074] That is, in plan view, second portion 191b of the induction heating coil crosses first portion 191a of the induction heating coil so as to overlap with the apex of the semi-elliptical meandering pattern formed by first portion 191a of the induction heating coil.

[0075] 3(b), the second portion 191b of the induction heating coil is wound around the first portion 191a of the induction heating coil so that it can cross the first portion 191a of the induction heating coil not only along the left side of the induction heating plate but also along the right side of the induction heating plate. That is, in a plan view, the second portion of the induction heating coil can be configured to surround the edge of the first portion of the induction heating coil.

[0076] 3(a), the plan view shows that the meandering-patterned first portion 191a of the induction heating coil and the linear second portion 191b of the induction heating coil are joined together to form multiple closed curves. The closed curves are arranged adjacent to each other in the longitudinal direction of the induction heating plate.

[0077] Each closed curve may constitute one induction heating unit.

[0078] In one embodiment of the present invention, the first and second portions of the induction heating coil may be shaped differently from those shown in FIGS. 3(a) and 3(b), without limitation. For example, the first portion of the induction heating coil may have a semi-elliptical serpentine pattern that abruptly bends at the apex, forming a sharper shape and zigzagging back and forth. As another example, the first serpentine pattern formed by the first portion of the induction heating coil may occupy half of the entire width of the induction heating plate 192, and the second serpentine pattern formed by the first portion of the induction heating coil may occupy half of the entire width of the induction heating plate 192 but be located on the other side of the first serpentine pattern. This arrangement can increase the surface area occupied by the induction heating coil on the induction heating plate. Furthermore, it is also possible to design the second portion of the induction heating coil in a different shape to increase or decrease the size of each induction heating unit. As an example, the second part of the induction heating coil may be positioned so that the portion extending in the longitudinal direction of the induction heating plate is offset from the central axis, or the second part of the induction heating coil may extend from one end of the heating plate to the opposite end and then return to the one end again, thereby forming more parallel portions extending in the longitudinal direction of the second part.

[0079] As a result, the induction heating device according to one embodiment of the present invention has a plurality of closed-curve-shaped induction heating units arranged closely adjacent to each other within the induction heating plate in the longitudinal direction of the induction heating plate, so that objects of various sizes can be heated regardless of their length as long as the width of the objects to be induction-heated is constant.

[0080] Meanwhile, referring to FIG. 4, unlike the embodiment referring to FIG. 3, the first portion 191a of the induction heating coil and the second portion 191b of the induction heating coil may be disposed on the same plane.

[0081] In this case, when the second portion 191b of the induction heating coil crosses the first portion 191a of the induction heating coil, the two portions may short-circuit each other, so the second portion 191b of the induction heating coil can be designed to avoid the first portion 191a of the induction heating coil where it meets the first portion 191a of the induction heating coil while crossing the first portion 191a of the induction heating coil.

[0082] As a result, as in the case of Fig. 3, referring to the plan view of Fig. 4(a), the meandering-patterned induction heating coil first portion 191a and the linear induction heating coil second portion 191b are joined together to form multiple closed curves in plan view. The multiple closed curves are arranged adjacent to each other in the longitudinal direction of the induction heating plate.

[0083] Each closed curve may constitute one induction heating unit.

[0084] While the explanation given with reference to Figures 3 and 4 can be understood as being limited to the case where the second part 191b of the induction heating coil overlaps the first part 191a of the induction heating coil when viewed in a plan view, the second part 191b of the induction heating coil can also surround the first part 191a of the induction heating coil at a certain distance outside the edge of the first part 191a of the induction heating coil.

[0085] In one embodiment of the present invention, the first and second portions of the induction heating coil may be shaped differently from those shown in FIGS. 4(a) and 4(b), without limitation. For example, the first portion of the induction heating coil may be bent sharply at the apex of a semi-elliptical serpentine pattern, forming a sharper, zigzag pattern. As another example, the first serpentine pattern formed by the first portion of the induction heating coil may occupy half of the entire width of the induction heating plate 192, and the second serpentine pattern formed by the first portion of the induction heating coil may occupy half of the entire width of the induction heating plate 192 but be located on the other side of the first serpentine pattern. This arrangement can increase the surface area occupied by the induction heating coil on the induction heating plate. Furthermore, the second portion of the induction heating coil may be designed to have a different shape to increase or decrease the size of each induction heating unit. As an example, the second part of the induction heating coil may be positioned so that the portion extending in the longitudinal direction of the induction heating plate is offset toward the central axis, or the second part of the induction heating coil may be configured to avoid the first part at each intersection, travel from one end of the heating plate to the opposite end, and then return to the one end again, thereby forming more parallel portions extending in the longitudinal direction of the second part.

[0086] As a result, it was confirmed that induction heating using the induction heating device of the present invention enabled uniform heating of the laminate, as shown in FIG.

[0087] That is, as can be seen from FIG. 5, the completed electrode assembly was observed and the adhesive force pattern was measured, and it was confirmed that the adhesive force pattern was uniform.

[0088] <Method for manufacturing electrode assembly> One embodiment of the present invention provides a method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, using the induction heating device of the present invention.

[0089] The method for manufacturing an electrode assembly according to the present invention is characterized in that it includes a step of induction heating the laminate between a stacking step for manufacturing the laminate and a heat pressing step for heating and pressurizing the laminate.

[0090] The heat pressing step includes a lower plate on which the electrode assembly to be heated and pressed is placed and to which heat can be applied, and an upper plate corresponding to the lower plate and to which heat can be applied. The lower plate and the upper plate may be a pair of pressure blocks.

[0091] In the heat pressing step of heating and pressing the electrode assembly, the electrodes located at the outermost portions of the laminate (the top and bottom ends of the laminate) are in direct physical contact with the bottom and top plates, and therefore may receive more heat and pressure than electrodes located in the middle of the laminate. This is because the heat pressing step involves heating while applying pressure in a state of physical contact with the top and bottom ends of the laminate.

[0092] That is, during the heat pressing step, the electrodes in the laminate may be heated to different temperatures depending on the position, and the electrodes and separators may have different adhesive strength depending on the position, which may result in uneven performance of the electrode assembly depending on the position.

[0093] Therefore, the method for manufacturing an electrode assembly according to the present invention is characterized in that a local region, particularly a center region, of a laminate is heated more intensely through an induction heating step, and the heat applied to the local region is diffused throughout the electrode assembly.The electrode assembly is then heated and pressed in a heat pressing step following the induction heating step, thereby heating the electrode assembly uniformly throughout.

[0094] As a result, it is possible to reduce the deviation in the air permeability of the separator inside the electrode assembly manufactured by the heat pressing step, and to reduce the deviation in the adhesive strength between the electrode and the separator, thereby manufacturing an electrode assembly with uniform performance.

[0095] In one embodiment of the present invention, the stacking step may include the steps of: supplying the first electrode to a stack table; supplying the second electrode to the stack table; and supplying the separation membrane to the stack table.

[0096] In this specification, "induction heating" refers to heating an object using electromagnetic induction. Joule heat is generated in the object due to an induced current generated in the object by electromagnetic induction. Therefore, induction heating is a heating method that can locally heat an object even if it is located a certain distance away from the heating element, compared to direct heating methods that heat an object by directly contacting it.

[0097] A coil can be used for the induction heating, which can be defined as an "induction heating coil." The induction heating method has the advantage that it is easy to adjust the heat and time applied to the object to be heated. In addition, non-contact heating is possible, so the object to be heated will not be damaged.

[0098] As used herein, the term "induction heating" may refer to locally heating a laminate using electromagnetic induction heating. The locally heated laminate may be an electrode disposed at the center of the laminate. When a direct heating method is used, the top or bottom electrode of the electrode assembly may heat more than the electrode at the center of the electrode assembly. However, in a method for manufacturing an electrode assembly according to one embodiment of the present invention, the center of the electrode assembly is first selectively heated using an induction heating method, and then the electrode assembly is heated using a direct heating method in a subsequent heat pressing step, thereby ultimately enabling the electrode assembly to be uniformly heated.

[0099] In one embodiment of the present invention, the induction heating step may inductively heat a portion of the laminate, and the heat may be diffused throughout the laminate to heat the entire laminate.

[0100] In one embodiment of the present invention, the induction heating step may inductively heat a first electrode or a second electrode in the laminate. More specifically, in one embodiment of the present invention, the induction heating step may inductively heat a first electrode or a second electrode disposed at the center of the laminate. In the heat pressing step, the first electrode or the second electrode disposed at the center of the laminate may receive relatively less heat than the first electrode or the second electrode disposed at the outermost periphery of the laminate. However, by first applying heat to the first electrode or the second electrode disposed at the center of the laminate in the induction heating step and then proceeding with the heat pressing step, heat can be applied uniformly throughout the laminate.

[0101] In this specification, induction heating of only a partial region (local region) of the surface of the laminate may include induction heating of the entire surface of the laminate, but the object of the present invention can be achieved even if only a partial region is induction heated. Also, it can be distinguished from heat pressing in that pressure is not applied to the laminate.

[0102] In one embodiment of the present invention, the induction heating step may be performed for 1 to 60 seconds, preferably 5 to 40 seconds, and more preferably 10 to 30 seconds. The induction heating time may be selected taking into consideration the degree to which the electrode assembly is heated unevenly in the heat pressing step.

[0103] In one embodiment of the present invention, the induction heating step may involve inductively heating the laminate using an induction heating coil.

[0104] The method for manufacturing an electrode assembly according to an embodiment of the present invention may include transferring the stack to a heat press after the stacking step. In order to transfer the stack in the transferring step, the stack may be gripped by a gripper.

[0105] The grippers are capable of maintaining a grip on the laminate during the heat pressing stage.

[0106] In a method for manufacturing an electrode assembly according to an embodiment of the present invention, the laminate may be induction heated while being transferred from the stack table to the heat press unit.

[0107] More specifically, in one embodiment of the present invention, the induction heating step further includes a transfer step in which the laminate is gripped with a gripper including an induction heating coil and transferred between the stacking step and the heat pressing step, and the induction heating step can be carried out by the gripper during the transfer step.

[0108] More specifically, in one embodiment of the present invention, the induction heating step may include the steps of gripping the laminate with a gripper including an induction heating coil; transferring the gripped laminate to a heat press step; and inductively heating the laminate with the induction heating coil of the gripper while transferring the laminate.

[0109] That is, since the induction heating coil is built into or attached to the gripper, there is no need to provide a separate space for induction heating, and the electrode assembly manufacturing device can be made compact.

[0110] In one embodiment of the present invention, the induction heating step may further include a transfer step of transferring the laminate to an induction heating device including an induction heating coil between the stacking step and the heat pressing step, and the induction heating step may be performed in the induction heating device. The induction heating device may be any type commonly used in the art as long as it can perform induction heating, or the induction heating device according to the present invention may be used.

[0111] More specifically, in one embodiment of the present invention, the induction heating step may include the steps of gripping the laminate with a gripper and transferring the gripped laminate to an induction heating device including an induction heating coil; and inductively heating the laminate in the induction heating device.

[0112] That is, instead of a configuration in which the induction heating coil is attached inside or outside the gripper, an induction heating device separate from the gripper may include the induction heating coil. When a separate induction heating device is used, there is an advantage that the induction heating step can be performed even if the thickness of the laminate including the electrodes and the separator is thick.

[0113] In addition, when a separate induction heating device is used as in the present invention, the electrode tab portion protruding from the electrode can be further heated by the induction heating device, thereby reducing the temperature difference between the electrode tab and the electrode.

[0114] In one embodiment of the present invention, the induction heating step may heat the laminate at a temperature of 40° C. or more and 90° C. or less, preferably 50° C. or more and 80° C. or less. When the laminate is induction heated within this temperature range, the laminate can be heated without damaging the electrodes and separators inside the laminate.

[0115] In one embodiment of the present invention, the induction heating coil may be in contact with the laminate or may be spaced a certain distance apart.

[0116] The induction heating coil can transfer heat to the maximum extent when it is in contact with the laminate (distance between the laminate and the induction heating coil is 0 mm), which has the advantage of being able to increase the internal temperature of the laminate even if induction heating is carried out for a short period of time.

[0117] In addition, when the induction heating coil is spaced a certain distance from the laminate, the heat generated by the induction heating coil can advantageously increase the temperature inside the laminate without damaging the laminate.

[0118] In one embodiment of the present invention, the certain distance may be 15 mm or less. More specifically, in one embodiment of the present invention, the certain distance may be greater than 0 mm and less than or equal to 15 mm, preferably greater than or equal to 0.05 mm and less than or equal to 10 mm, and more preferably greater than or equal to 0.3 mm and less than or equal to 5 mm. When the certain distance is satisfied, as described above, the electrodes can be induction heated without damaging the laminate.

[0119] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include removing the induction heating unit from the path of movement of the electrode assembly before the heat pressing step, thereby preventing physical collision between the induction heating unit and the heat pressing unit.

[0120] Furthermore, physical collision between the gripper and the heat press unit can also be prevented through the first and second heat press stages described below.

[0121] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include a waiting step of waiting the laminate in an atmospheric condition for a predetermined time between the induction heating step and the heat pressing step. The atmospheric condition refers to stopping the induction heating for a predetermined time after the induction heating step and waiting for the heat applied to the laminate by the induction heating to diffuse throughout the laminate.

[0122] The heat transferred to a portion of the laminate during the waiting step can be transferred to the entire laminate. By intentionally halting induction heating of the laminate for a certain period of time before proceeding with the heat pressing step, the heat transferred to the laminate by induction heating can be diffused evenly throughout the entire laminate.

[0123] Then, the laminate is heated and pressed in a subsequent heat press step, thereby improving the uniformity of the electrode thickness throughout the electrode assembly.

[0124] In one embodiment of the present invention, the waiting step may proceed for a period of not less than 3 seconds and not more than 60 seconds, preferably not less than 5 seconds and not more than 45 seconds, more preferably not less than 10 seconds and not more than 40 seconds.

[0125] When this time range is satisfied, it is possible to ensure that the heat transferred to a portion of the electrode inside the laminate by induction heating is evenly distributed throughout the laminate. That is, if the waiting step is performed for less than 3 seconds, the heat transferred to a portion of the laminate is not easily transferred to the entire electrode. On the other hand, if the waiting step is performed for more than 60 seconds, the temperature of the electrode, which was increased by the transferred heat, may cool down, resulting in a decrease in the effectiveness of the induction heating.

[0126] The waiting time may vary depending on the time and temperature range to which the laminate is heated in the subsequent heat pressing step.

[0127] In one embodiment of the present invention, the step of manufacturing a stack in which first and second electrodes are alternately arranged between folded separators may be performed using a technique commonly used in the art. For example, the step may involve stacking first electrodes on the stack table, covering the first electrodes with a separator, stacking a second electrode on the separator, folding the separator to cover the second electrode, and then stacking the first electrode on the separator, repeating this process. This is referred to as a zigzag stacking method in this embodiment. In this case, the step of moving the separator while covering the first or second electrode placed on the separator may be performed using a method in which the stack table moves left and right, a method in which the separator moves left and right, or a method in which the stack table rotates.

[0128] In the zigzag stacking method, a holding mechanism holds the stack, thereby maintaining the alignment of the stack while the first electrode, the second electrode, and the separator are stacked.

[0129] In this specification, the term "holding mechanism" refers to a mechanism that grips the laminate placed on the stack table in order to stack the first electrode or the second electrode in the zigzag stacking method, and is different from the gripper that grips the laminate in the heat pressing stage.

[0130] In one embodiment of the present invention, the separation membrane may be provided in the form of a separation membrane sheet. That is, the additional separation membrane may be provided in a continuous form. Also, the "upper surface" may refer to the surface opposite to the surface on which the separation membrane or electrode is placed on the stack table.

[0131] The method for manufacturing an electrode assembly according to an embodiment of the present invention may include a heat-pressing step of heating and pressurizing the induction-heated laminate as described above. The heat-pressing step may heat the laminate while pressing it in the lamination axis direction. The heat-pressing step may be performed by a heat press unit, which will be described later.

[0132] Furthermore, in one embodiment of the present invention, the heat pressing step may include the steps of: moving the laminate between a pair of pressure blocks including a press heater; moving the pair of pressure blocks toward each other in the stacking axis direction to apply surface pressure to the laminate; and heating the laminate.

[0133] The pair of pressure blocks may be a lower plate and an upper plate facing the lower plate.

[0134] Furthermore, in one embodiment of the present invention, the heat pressing step may include the steps of: moving the laminate between a pair of pressure blocks; moving the pair of pressure blocks in the lamination axis direction to apply surface pressure to the laminate; and heating the laminate by a separately provided press heater.

[0135] That is, the press heater may be included in the pressurizing block, or may be provided as a separate structure.

[0136] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include a step of releasing the grip of the grippers before the heat pressing step.

[0137] That is, the step of loosening the grip of the gripper may include the steps of: stopping the gripper from pressing the upper surface of the stack; and moving the gripper away from the stack.

[0138] In addition, the step of moving the laminate between a pair of pressure blocks including a press heater in the heat pressing step may include not only moving the laminate itself but also moving the laminate together with the stack table while the laminate is placed on the stack table. In this case, the objects to be heated and pressed by the pair of pressure blocks and the press heater may refer to the laminate and the stack table.

[0139] In one embodiment of the present invention, the heat pressing step may involve heating and pressing the laminate at a temperature of 50°C to 90°C and a pressure of 0.5 MPa to 6.0 MPa for 5 to 60 seconds. More preferably, the laminate may be heated and pressed at a temperature of 65°C to 90°C and a pressure of 1.0 MPa to 6.0 MPa for 5 to 30 seconds. More preferably, the laminate may be heated and pressed at a temperature of 65°C to 85°C and a pressure of 3 MPa to 5.5 MPa for 7 to 25 seconds.

[0140] When heating and pressurizing are performed while satisfying the above conditions, the adhesive strength between the first electrode and the separator and between the separator and the second electrode can be improved without damaging the first electrode, the separator, and the second electrode, thereby improving the performance of the electrode assembly.

[0141] In one embodiment of the present invention, the heat pressing step is not in progress while the induction heating step is in progress.

[0142] In one embodiment of the present invention, the induction heating step may include measuring a temperature distribution on the surface of the laminate; setting an induction heating temperature for the laminate in accordance with the measured temperature distribution; and inductively heating the laminate based on the set induction heating temperature. That is, by adjusting the induction heating temperature of the laminate in accordance with the measured temperature distribution on the top surface of the laminate, the electrodes can be induction heated efficiently without using unnecessary energy.

[0143] <Electrode assembly manufacturing equipment> One embodiment of the present invention provides an apparatus for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, which utilizes the induction heating apparatus of the present invention.

[0144] For reference, a semi-finished product state in which a first electrode, a separator, and a second electrode are repeatedly stacked can be referred to as a laminate, and a separate component obtained by performing a separator winding process on the semi-finished product can be classified as an electrode assembly.

[0145] The electrode assembly manufacturing apparatus according to the present invention is characterized by including an induction heating unit. The induction heating unit of the electrode assembly manufacturing apparatus according to the present invention performs the induction heating step described above. That is, when the electrode assembly manufacturing apparatus according to the present invention is used, the laminate including the first electrode, separator, and second electrode is uniformly heated during the heat pressing step performed by the heat press unit, thereby ensuring uniform adhesive strength between each layer within the laminate. This reduces variations in separator permeability, separator thickness, and adhesive strength depending on the stacking position of the electrode assembly, thereby enabling the manufacture of an electrode assembly with uniform performance while reducing the volume of the electrode assembly. Furthermore, an electrode assembly with increased energy density per unit volume can be manufactured.

[0146] The electrode assembly manufacturing apparatus according to the present invention may further include a separation membrane supply unit that supplies a separation membrane to the stack table; a first electrode supply unit that supplies a first electrode to the stack table; and a second electrode supply unit that supplies a second electrode to the stack table.

[0147] In one embodiment of the present invention, the induction heating unit may be a gripper that grips the laminate to transfer it to the heat press unit. The gripper may include an induction heating coil. The induction heating coil may be built into the gripper as described above, or may be provided outside the gripper. When the gripper serves as the induction heating unit, a process space for providing the induction heating unit can be saved, and induction heating can be performed while the laminate is being transferred, thereby shortening the process time. The gripper can function to grip the laminate while transferring it from the stack table to the heat press unit.

[0148] In one embodiment of the present invention, the induction heating unit may be provided separately from the gripper that transports the laminate. That is, the induction heating unit may include an induction heating device including an induction heating coil; and a moving unit that moves the induction heating device to the surface of the laminate. When the moving unit moves the induction heating device to an appropriate distance from the laminate, the induction heating device can inductively heat the laminate. When induction heating of the laminate is completed, the moving unit can move the induction heating device away from the laminate.

[0149] In this case, as described above, there is an advantage that it can be easily applied even when the thickness of the laminate is large, and there is also an advantage that it can be used when induction heating the electrode tabs.

[0150] In this specification, the term "unit" refers to an interface that performs a specific function within an electrode assembly manufacturing apparatus.

[0151] The induction heating coil of the electrode assembly manufacturing apparatus according to one embodiment of the present invention may be in contact with or spaced apart from the laminate by a predetermined distance, and the predetermined distance may be 15 mm or less, more specifically, greater than 0 mm and 15 mm or less, preferably 0.05 mm to 10 mm, and more preferably 0.3 mm to 5 mm.

[0152] The advantages of the induction heating coil being in contact with the laminate and the advantages of the induction heating coil being spaced a certain distance from the laminate are as described in the method of manufacturing the electrode assembly.

[0153] The electrode assembly manufacturing apparatus according to an embodiment of the present invention may further include a control unit that measures a temperature distribution on the surface of the laminate and sets an induction heating temperature for the laminate in accordance with the measured temperature distribution, or determines whether to interrupt induction heating of the laminate based on the induction heating temperature and the induction heating time for the laminate.

[0154] The control unit can also adjust the induction heating time for the laminate.

[0155] That is, the control unit can set a condition for performing the induction heating step and a condition for performing the waiting step, and the same conditions as those described above in the method for manufacturing an electrode assembly can be applied to each of the conditions.

[0156] In one embodiment of the present invention, the heat press unit may be composed of a pair of pressure blocks, which move in directions opposite to each other to apply surface pressure to the laminate.

[0157] The heat press unit includes a pair of pressure blocks and a press heater for heating the pressure blocks. While the press heater heats the pressure blocks, the pair of pressure blocks move toward each other, thereby applying surface pressure to the laminate placed between the pressure blocks.

[0158] In this case, the pair of pressurizing blocks may include press heaters therein.

[0159] In another embodiment of the present invention, the heat press unit may be divided into two heat press units, i.e., it may include a first heat press unit and a second heat press unit.

[0160] Referring to FIG. 7, the first heat press unit may include a pair of first pressure blocks. The pressure surfaces of the pair of first pressure blocks may include grooves shaped to correspond to the grippers so that the grippers can press the laminate while gripping the laminate. The pressure surfaces other than the grooves may be flat. The second heat press unit may include a pair of second pressure blocks. The pressure surfaces of the pair of second pressure blocks may be flat. That is, when the laminate is placed on the pressure surfaces of the pressure blocks, the second pressure blocks can move relative to each other to heat and press the laminate.

[0161] Dividing the heat press into two sections as described above allows the heated laminate to cool while being transported, preventing the adhesive strength between the layers within the laminate from being lost.

[0162] The conditions for heating and pressing the laminate in the heat press section are the same as those in the heat press step described above.

[0163] In one embodiment of the present invention, the stack table may include a table body on which the stack material is placed and a drive unit that drives the table body. The table body may include a stack table heater that can heat the stack material to a predetermined temperature when the stack material is placed on the table body.

[0164] In one embodiment of the present invention, the first electrode supply unit may include at least one of a first electrode placing table, a first electrode roll, a first cutter, a first conveyor belt, and a first electrode supply head.

[0165] Furthermore, the first electrode placement table may include a first electrode heater that heats the first electrode placed on the first electrode placement table to a predetermined temperature.

[0166] In one embodiment of the present invention, the second electrode supply unit may include at least one of a second electrode placing table, a second electrode roll, a second cutter, a second conveyor belt, and a second electrode supply head.

[0167] Furthermore, the second electrode placement table may include a second electrode heater that heats the second electrode placed on the second electrode placement table to a predetermined temperature.

[0168] In one embodiment of the present invention, the first electrode stack unit may include a first suction head that vacuum-sucks the first electrode placed on the first electrode placement table. The first electrode can be moved from the first electrode placement table to the stack table via the first electrode stack unit.

[0169] The second electrode stack unit may include a second suction head that vacuum-sucks the second electrode placed on the second electrode placement table. The second electrode can be moved from the second electrode placement table to the stack table via the second electrode stack unit.

[0170] In one embodiment of the present invention, the first electrode may be a positive electrode and the second electrode may be a negative electrode.

[0171] In one embodiment of the present invention, the first electrode may be a negative electrode and the second electrode may be a positive electrode.

[0172] In one embodiment of the present invention, current collectors, active materials, conductive materials, etc. used in the positive and negative electrodes may be any materials known in the art, and methods for manufacturing the positive and negative electrodes may be any methods known in the art, without limitation.

[0173] In one embodiment of the present invention, the separator may be made of any active material known in the art, and any method known in the art may be used for manufacturing the separator. However, in one embodiment of the present invention, the separator may include a porous polymer substrate and an organic / inorganic composite porous coating layer formed on at least one surface of the polymer substrate, and the organic / inorganic composite porous coating layer may include a particulate binder resin and inorganic particles.

[0174] In one embodiment of the present invention, the particulate binder resin may include at least one selected from the group consisting of fluorine-based polymers, acrylic polymer particles, acrylic polymer particles, and hybrid acrylic polymer particles.

[0175] In one embodiment of the present invention, the fluorine-based polymer may be a homopolymer of vinylidene fluoride, a copolymer of vinylidene fluoride and another polymerizable monomer, or a mixture of two or more thereof.

[0176] In one embodiment of the present invention, the inorganic particles may be, but are not limited to, Al2O3.

[0177] Because the organic / inorganic composite porous coating layer is included, an electrode assembly with enhanced adhesion between the electrodes and the separator can be manufactured by applying the induction heating step and the heat press step described in the electrode assembly manufacturing method and / or electrode assembly manufacturing apparatus.

[0178] An electrode assembly manufacturing apparatus and an electrode assembly manufacturing method according to an embodiment of the present invention will be described in more detail below, assuming that the electrode assembly of the present invention is stacked in a zigzag pattern.

[0179] Fig. 6 shows a cross-sectional view of the process flow of an electrode assembly manufacturing apparatus according to one embodiment of the present invention, and Fig. 7 shows a plan view of the process flow of an electrode assembly manufacturing apparatus according to one embodiment of the present invention. For convenience, Fig. 6 omits the holding mechanism 170, heat press unit 180, and induction heating device 190 shown in Fig. 7, and Fig. 7 omits the separation membrane supply unit 120 shown in Fig. 6.

[0180] 6 to 8, an electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention includes a separation membrane supply unit 120 that supplies a separation membrane 14 to a stack table 110, a first electrode supply unit 130 that supplies a first electrode 11 to the stack table 110, and a second electrode supply unit 140 that supplies a second electrode 12 to the stack table 110. In this case, the separation membrane 14, the first electrode 11, and the second electrode 12 may be heated in the first electrode supply unit 130 and the second electrode supply unit 140, respectively, and then supplied to the stack table 110.

[0181] Additionally, the electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention includes a first electrode stacking unit 150 that stacks the first electrodes 11 supplied by the first electrode supply unit 130 on the stack table 110, and a second electrode stacking unit 160 that stacks the second electrodes 12 supplied by the second electrode supply unit 140 on the stack table 110. The separation membranes 14 supplied by the separation membrane supply unit 120 are stacked in a zigzag pattern, alternately moving back and forth between the left and right sides of the stacking axis. The first electrodes 11 and the second electrodes 12 are alternately inserted into spaces (between the separation membranes) generated by the folding of the separation membranes 14. As a result, a stack in which the first electrodes 11, separation membranes 14, second electrodes 12, and separation membranes 14 are repeatedly stacked is placed on the stack table 110.

[0182] The separation membrane supply unit 120 may include a separation membrane heating unit 121 and a separation membrane roll 122. The separation membrane heating unit 121 is optional.

[0183] More specifically, the first electrode supply unit 130 may include a first electrode mounting table 131, a first electrode heater (not shown), a first electrode roll 133, a first cutter 134, a first conveyor belt 135, and a first electrode supply head 136. The first electrode heater (not shown) is selectively applicable.

[0184] The second electrode supply unit 140 may also include a second electrode mounting table 141, a second electrode heater (not shown), a second electrode roll 143, a second cutter 144, a second conveyor belt 145, and a second electrode supply head 146. The second electrode heater (not shown) is selectively applicable.

[0185] The first electrode stacking unit 150 stacks the first electrodes 11 on the stack table 110. At this time, the first electrode stacking unit 150 may include a first suction head 151, a first head heater (not shown), and a first moving unit 153. The second electrode stacking unit 160 stacks the second electrodes 12 on the stack table 110. The second electrode stacking unit 160 may include a second suction head 161, a second head heater (not shown), and a second moving unit 163.

[0186] The first electrode stack unit 150 and the second electrode stack unit 160 may further include a heater (not shown) for preheating the first electrode and the second electrode, as the case may be.

[0187] Furthermore, the electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention may further include a holding mechanism 170 that fixes the first electrode 11 and the second electrode 12 when they are stacked on the stack table 110. Furthermore, the electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention includes a heat press unit 180 that applies heat and pressure to the stack placed on the stack table 110 to bond the first electrode 11, the separator 14, and the second electrode 12 together.

[0188] The electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention further includes an induction heating device 190 that inductively heats the laminate and transfers heat to the electrodes in the laminate. The apparatus may also include a control unit (not shown) that controls whether the induction heating unit 190 is operated. As a result, the electrode assembly 10 shown in FIG. 8 can be finally manufactured.

[0189] FIG. 8 is a cross-sectional view illustrating an example of an electrode assembly manufactured by an apparatus for manufacturing an electrode assembly and a method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0190] Referring to FIG. 8, the electrode assembly 10 may have a configuration in which separators that are folded in a zigzag pattern and stacked, and first electrodes or second electrodes that are inserted into spaces between the separators, are alternately stacked.

[0191] In this case, the electrode assembly 10 may be provided in a form in which the outermost periphery of the laminate is wrapped with the separator 14. However, the configuration of the electrode assembly 10 is not limited to the example shown in FIG.

[0192] 9 and 10 are diagrams that schematically show the operation process of the induction heating unit according to the present invention.

[0193] Specifically, FIG. 9 illustrates a case where the induction heating unit 190 is a gripper 51. The gripper 510 may include an induction heating coil (not shown). The gripper 51 may perform induction heating on the laminate S while gripping the laminate S. While the gripper 51 is performing induction heating, the laminate S may be transferred to the heat press unit 180. The heat press unit 180 may heat and pressurize the laminate S. In this case, before the heat press unit 180 heats and pressurizes the laminate S, the induction heating of the laminate S may be stopped and a standby process (step) may be performed in which the laminate S is allowed to wait for a certain period of time. In this case, the conditions for the standby process may be set by a control unit (not shown).

[0194] FIG. 10 shows another embodiment of induction heating, in which the laminate S is induction heated using an induction heating device 190 provided separately from the gripper 51. In this case, the laminate S is transferred to the induction heating device and then induction heated. Once induction heating is complete, the laminate S can be heated and pressed in the heat press unit 180, as in FIG. 4. In this case, before heating and pressing the laminate S in the heat press unit 180, a waiting process (step) may be performed in which the induction heating of the induction-heated laminate S is stopped and the laminate S waits for a certain period of time. In this case, the conditions for the waiting process may also be controlled by a control unit (not shown). The waiting process may be performed in a state in which the laminate S is gripped by the gripper 51, away from the induction heating unit 190, as shown in FIG.

[0195] The induction heating unit 190 in FIGS. 9 and 10 may use the induction heating device according to the present invention.

[0196] The present invention is characterized in that, in the heat pressing step in which the electrode assembly is heated and pressed, the electrode located in the center of the positive assembly, which is particularly vulnerable to heat, is targeted and pre-heated by induction heating before the heat pressing step.

[0197] FIG. 11 shows the configuration of the heat presses 50, 60, and particularly shows the case where the heat press units 50, 60 include a first heat press unit 50 and a second heat press unit 60.

[0198] FIG. 11(a) is a perspective view showing the first heat press unit 50, and FIG. 11(b) is a perspective view showing the second heat press unit 60. As shown in FIG.

[0199] 11(a), the first heat press unit 50 can apply heat and pressure to the laminate S while it is fixed with the gripper 51. The first heat press unit 50 may be composed of a pair of first pressure blocks 50a and 50b. The pair of first pressure blocks 50a and 50b have flat pressure surfaces except for a groove corresponding to the fixing portion 51b of the gripper 51.

[0200] The gripper 51 may include a main body 51a that corresponds to the length x and height y of the stack S or is wider than the length x and height y of the stack S, and a fixing portion 51b that protrudes from the main body 51a and grips the stack S. Here, the length x of the stack S may refer to the longest distance from one end to the other end of the stack S, the height y may refer to the distance in the stacking direction of the stack S, and the width z may refer to the distance across the top surface of the stack S.

[0201] The fixing portion 51b can be adjusted in position along the height direction of the main body 51a, and the fixing portion 51b can contact the upper and lower surfaces of the stack S to fix the stack S.

[0202] Thereafter, the pair of first pressure blocks 50a and 50b move in opposite directions to heat and pressurize the laminate S. The heating and pressing stably bond the electrodes and separators in the electrode assembly.

[0203] The first heat press unit 60 may be a component that complements the cooling of the induction-heated electrode assembly while it is moving, and may be provided as an optional component. That is, it may be omitted in some cases.

[0204] 11(b), the second heat press unit 60 can finally heat and pressurize the laminate S that has been primarily heated and pressed by the first heat press unit 50. The second heat press unit 60 includes a pair of second pressure blocks 60a and 60b, and the pair of pressure blocks 61 and 62 can move in directions opposite to each other to apply surface pressure to the laminate S. In addition, the pair of second pressure blocks 60a and 60b included in the second heat press unit 60 may all have flat pressure surfaces that come into contact with and pressurize the laminate S.

[0205] The description of the method for manufacturing an electrode assembly according to the present invention can also be applied to the apparatus for manufacturing an electrode assembly according to the present invention, and vice versa.

[0206] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to those skilled in the art that various modifications and variations are possible within the scope that does not deviate from the technical idea of ​​the present invention described in the claims. [Explanation of symbols]

[0207] 10...electrode assembly 11...1st electrode 12...Second electrode 14...Separation membrane 50 First heat press section 50a, 50b: A pair of first pressure blocks 51 Gripper 51a Main body 51b...Fixed part 60 Second heat press section 60a, 60b: A pair of second pressure blocks 90 Existing induction heating equipment 91 (91a, 91b) Induction heating coil 92 (92a, 92b) Induction heating plate 100 Electrode assembly manufacturing apparatus 110 Stack Table 111 Table body 112 Stack Table Heater 120...Separation membrane supply section 121 Separation membrane heating section 122 Separation membrane roll 130...First electrode supply section 131 First electrode placement table 133 First electrode roll 134 First cutter 135 No. 1 conveyor belt 136 First electrode supply head 140...Second electrode supply section 141 Second electrode placement table 143 Second electrode roll 144 Second cutter 145 Second conveyor belt 146 Second electrode supply head 150 First electrode stack section 151 First suction head 153 First moving part 160 Second electrode stack section 161 Second suction head 163 Second moving part 170 ···Holding mechanism 171 First holding mechanism 172 Second holding mechanism 180 Heat press section 181 First pressure block 182 Second pressure block 190...Induction heating device 191 Induction heating coil 191a...First part of induction heating coil 191b Second part of induction heating coil 191c...Third part of induction heating coil 192 Induction Heating Plate S ···Laminate

Claims

1. An induction heating device comprising: at least one induction heating plate having main surfaces along a longitudinal direction and a width direction, for inductively heating an electrode assembly; and an induction heating coil built into the induction heating plate, The induction heating coil is a first portion of the induction heating coil having a serpentine pattern that is serpentine to a first depth in a thickness direction perpendicular to a major surface of the induction heating plate; and a second portion of the induction heating coil extending around the induction heating plate to a second depth in a thickness direction perpendicular to the major surface of the induction heating plate; 1. An induction heating device comprising:

2. The induction heating apparatus of claim 1 , wherein a main surface of the induction heating plate is positioned to face the electrode assembly to be induction heated.

3. The induction heating device of claim 1 , wherein the first and second portions of the induction heating coil extend in a direction aligned with a major surface of the induction heating plate.

4. the at least one induction heating plate includes a first induction heating plate on which the electrode assembly is placed, the first induction heating plate including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode; and The induction heating device according to claim 1 , further comprising a second induction heating plate disposed opposite the first induction heating plate.

5. 2. The induction heating device of claim 1, further comprising a third portion of the induction heating coil connecting the first portion of the induction heating coil and the second portion of the induction heating coil, the first depth and the second depth being different from each other.

6. 2. The induction heating device of claim 1, wherein the first depth and the second depth are the same, but the second portion of the induction heating coil is avoided from shorting with the first portion of the induction heating coil.

7. 2. The induction heating device according to claim 1, wherein, when viewed in a thickness direction perpendicular to a main surface of the at least one induction heating plate, the second portion of the induction heating coil crosses the first portion of the induction heating coil so as to overlap an apex formed in the first portion of the induction heating coil.

8. 2. The induction heating device of claim 1, wherein the second portion of the induction heating coil surrounds an edge of the first portion of the induction heating coil when viewed in a thickness direction perpendicular to a main surface of the at least one induction heating plate.

9. 2. The induction heating device according to claim 1, wherein when viewed in a thickness direction perpendicular to a main surface of the at least one induction heating plate, the first portion of the induction heating coil and the second portion of the induction heating coil form at least one closed curve.

10. The induction heating device of claim 1 , wherein the at least one induction heating plate comprises a non-conductive material.

11. The induction heating device of claim 1 , wherein the first portion of the induction heating coil moves back and forth in the width direction of the induction heating plate while progressing in the length direction of the induction heating plate to form a serpentine pattern.

12. The first portion of the induction heating coil reciprocates in the width direction of the induction heating plate and forms a semi-elliptical shape, The semi-elliptical shape has a longer radius in a width direction of the induction heating plate and a shorter radius in a longitudinal direction of the induction heating plate, The long radius is equal to or greater than 50 mm and equal to or less than 80 mm, 2. The induction heating device of claim 1, wherein the short radius is between 10 mm and 40 mm.

13. The induction heating device according to claim 12 , wherein the semi-elliptical shapes are periodically arranged in the longitudinal direction of the induction heating plate.

14. The induction heating device according to claim 13, wherein the period is equal to or greater than 10 mm and equal to or less than 30 mm.

15. A method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, comprising: stacking a stack including the first electrode, the separator, and the second electrode on a stack table; an induction heating step of inductively heating the laminate with an induction heating device according to any one of claims 1 to 14; and a heat press step of heating and pressing the induction-heated laminate; A method for manufacturing an electrode assembly, comprising:

16. An apparatus for manufacturing an electrode assembly, which manufactures an electrode assembly including a first electrode, a separator, and a second electrode, a stack table on which the first electrode, the separation film, and the second electrode are stacked and on which the stack including the first electrode, the separation film, and the second electrode is placed; a heat press unit for heating and pressing the laminate; and an induction heating section for induction heating the laminate before the laminate is heated and pressurized in the heat press section; Including, The electrode assembly manufacturing apparatus, wherein the induction heating unit is the induction heating device according to any one of claims 1 to 14.

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