Electrode assembly, manufacturing method thereof, and manufacturing device thereof

Abstract

The present invention relates to an electrode assembly, a manufacturing method for an electrode assembly, and a manufacturing apparatus for an electrode assembly, and includes a stacking step of stacking a laminate including a first electrode, a separator, and a second electrode on a stack table, an induction heating step of inductively heating the laminate, and a heat press step of heating and pressurizing the induction-heated laminate, thereby reducing temperature deviation between electrodes and providing an electrode assembly with uniform performance.

Description

[Technical Field]

[0001] The present invention claims the benefit of the filing dates of Korean Patent Application No. 10-2023-0000712 filed with the Korean Intellectual Property Office on January 3, 2023, Korean Patent Application No. 10-2023-0056357 filed with the Korean Intellectual Property Office on April 28, 2023, and Korean Patent Application No. 10-2023-0195875 filed with the Korean Intellectual Property Office on December 29, 2023, the contents of which are incorporated herein in their entirety.

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

[0003] Unlike primary batteries, secondary 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 growing rapidly.

[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 and is made up of a laminated structure of electrodes and a separator.

[0005] Electrode assemblies can be broadly classified into a jelly-roll type in which a sheet-type positive electrode and a sheet-type negative electrode coated with active materials are wound up with a separator interposed between them, a stack type in which multiple positive electrodes and negative electrodes are stacked in order 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] Here, in the stack-and-fold type electrode assembly, the separator is folded in a zigzag pattern and stacked, and the positive or negative electrode is inserted between the folded separators to manufacture 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 separators within the laminate requires a lot of time and energy.

[0009] Furthermore, when heat and pressure are applied to the laminate, the difference in stacking positions (stacking height) of the electrodes and separator within the laminate prevents the heat and pressure from being applied uniformly, regardless of the stacking positions of the electrodes and separator, resulting in 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. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-2013-0132230 Summary of the Invention [Problem to be solved by the invention]

[0012] SUMMARY OF THE INVENTION The present invention provides an electrode assembly, a manufacturing method thereof, and a manufacturing apparatus thereof that solves the problems caused by inconsistent adhesive strength. [Means for solving the problem]

[0013] 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; and a heat pressing step of heating and pressing the induction-heated laminate.

[0014] 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, comprising: 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.

[0015] One embodiment of the present invention provides an electrode assembly including a first electrode, a separator, and a second electrode, wherein the electrode assembly is zigzag stacked, and after the zigzag stacking, the electrode assembly is heated and pressurized, so that the electrode assembly satisfies the following formula 1: [Formula 1] 1.02E A ≦E B In the formula 1, E A is the energy density (Wh / L) of the electrode assembly before heating and pressure application, E B is the energy density (Wh / L) of the electrode assembly after heating and pressure application. [Effects of the Invention]

[0016] The electrode assembly manufacturing method and electrode assembly manufacturing apparatus according to the embodiments of the present application can reduce the time required to manufacture an electrode assembly.

[0017] 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 within a specific temperature range and reduce the temperature deviation between the electrodes, thereby providing an electrode assembly with uniform performance.

[0018] The electrode assembly according to the embodiment of the present application has an advantage that the deviation in the air permeability of the separator depending on the position is small and the performance is uniform. [Brief explanation of the drawings]

[0019] [Figure 1] 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 2] 1 is a front view illustrating a concept of an electrode assembly manufacturing apparatus according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view showing an example of a conventional electrode assembly. [Figure 4] 1A to 1C are diagrams illustrating a process of applying a method or apparatus for manufacturing an electrode assembly according to an embodiment of the present invention; [Figure 5] 1A to 1C are diagrams illustrating a process of applying a method or apparatus for manufacturing an electrode assembly according to an embodiment of the present invention; [Figure 6] 1 is a diagram illustrating an example of an induction heating unit according to an embodiment of the present invention. [Figure 7] 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. [Figure 8] 10 is a diagram showing the results of measuring the change in surface temperature of a laminate during the process of manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 9] FIG. 10 shows the adhesive force pattern of an electrode assembly according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0021] In this specification, when a part is said to "comprise" a certain component, this does not mean that it may further include other components, unless specifically stated to the contrary, but rather that it does not exclude other components.

[0022] 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.

[0023] In this specification, the stacking of the first electrode and the second electrode alternately between the folded separator is referred to as zigzag stacking.

[0024] In this regard, the alternate arrangement of the first and second electrodes between the folded separators may be described in more detail as a separator in which the separators are stacked in a zigzag pattern. More specifically, the separators are stacked in a zigzag pattern while being folded alternately to the left and right of the stacking axis. The stacking 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.

[0025] That is, 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) that are generated as the separation membranes are stacked.

[0026] <Electrode assembly manufacturing method> One embodiment of the present invention provides a method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode.

[0027] 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 pressing the laminate.

[0028] The heat pressing step includes a lower plate on which the electrode assembly to be heated and pressed is placed and to which heat is applied, and an upper plate to which heat is applied corresponding to the lower plate. The upper plate and the lower plate may be a pair of pressure blocks.

[0029] During 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 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.

[0030] That is, during the heat pressing step, the electrodes within the laminate may be heated to different temperatures depending on the position, and the electrodes and separators may have different adhesive strengths depending on the position, which may result in uneven performance of the electrode assembly depending on the position.

[0031] Therefore, in the method for manufacturing an electrode assembly according to the present invention, more heat is applied to a local region, particularly a center region, of the laminate in the 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.

[0032] This reduces the deviation in air permeability of the separator inside the electrode assembly manufactured through the heat pressing step, and reduces the deviation in adhesive strength between the electrode and the separator, thereby manufacturing an electrode assembly with uniform performance.

[0033] 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.

[0034] 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 a heating element, compared to direct heating methods that heat an object by directly contacting the object.

[0035] A coil can be used for induction heating, which can be defined as an "induction heating coil." The induction heating method has the advantage of being easy to control the heat and time applied to the object to be heated. It also allows for non-contact heating, which does not damage the object to be heated.

[0036] As used herein, the term "induction heating step" 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 be heated more than the central electrode 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 allowing the electrode assembly to be uniformly heated.

[0037] In one embodiment of the present invention, the induction heating step inductively heats a portion of the laminate, and the heat is diffused throughout the laminate, thereby heating the entire laminate.

[0038] In one embodiment of the present invention, the induction heating step may inductively heat the first or second electrode of the laminate. More specifically, in one embodiment of the present invention, the induction heating step may inductively heat the first or second electrode disposed at the center of the laminate. In the heat pressing step, the first or second electrode disposed at the center of the laminate may receive relatively less heat than the first or second electrode disposed at the outermost periphery of the laminate. However, by first applying heat to the first or second electrode disposed at the center of the laminate during the induction heating step and then performing the heat pressing step, heat can be applied uniformly throughout the laminate.

[0039] In this specification, induction heating of only a partial region (local region) on the surface of the laminate may be included, but the purpose of the present invention can be achieved even if only a partial region is induction heated. Also, it is distinguished from heat pressing in that pressure is not applied to the laminate.

[0040] 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.

[0041] In one embodiment of the present invention, the induction heating step may involve inductively heating the laminate using an induction heating coil.

[0042] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include, after the stacking step, transferring the laminate to a heat press step. In the transferring step, the laminate may be gripped by a gripper to transfer the laminate.

[0043] The grippers are capable of maintaining a grip on the laminate during the heat pressing stage.

[0044] 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.

[0045] 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 press step, and the induction heating step can be performed with the gripper during the transfer step.

[0046] 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.

[0047] 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 apparatus can be made compact.

[0048] Meanwhile, in one embodiment of the present invention, the induction heating step may further include a transfer step of transferring the laminate between the stacking step and the heat pressing step to an induction heating device including an induction heating coil, and the induction heating step may be performed using 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.

[0049] More specifically, in one embodiment of the present invention, the induction heating step may include a transfer step of gripping the laminate with a gripper and transferring the gripped laminate to an induction heating device including an induction heating coil; and a step of inductively heating the laminate in the induction heating device. More specifically, the induction heating step may involve inductively heating the laminate while it is gripped by the gripper. In this way, after the laminate is gripped by the gripper, it can be transferred to the heating and pressurizing step through the induction heating step without unnecessary pauses. In other words, it is possible to avoid repeatedly gripping and unraveling the laminate between adjacent steps.

[0050] 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.

[0051] Furthermore, when a separate induction heating device is used as in the present invention, the electrode tab portion protruding from the electrode can be additionally heated by the induction heating device, thereby reducing the temperature difference between the electrode tab and the electrode.

[0052] In one embodiment of the present invention, the induction heating step may heat the laminate at a temperature of 40° C. to 90° C., preferably 50° C. to 80° C. When the laminate is induction heated within this temperature range, the laminate can be heated without damaging the electrodes and separators inside the laminate.

[0053] In one embodiment of the present invention, the induction heating coil may be in contact with the laminate or may be spaced a predetermined distance from the laminate.

[0054] 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 that the internal temperature of the laminate can be increased even if induction heating is performed for a short period of time.

[0055] In addition, when the induction heating coil is spaced a predetermined distance from the laminate, the laminate is not damaged by the heat generated by the induction heating coil, and the temperature inside the laminate can be increased.

[0056] In one embodiment of the present invention, the predetermined distance may be 15 mm or less. More specifically, in one embodiment of the present invention, the predetermined distance may be greater than 0 mm and less than or equal to 15 mm, preferably 0.05 mm or more and 10 mm or less, and more preferably 0.3 mm or more and 5 mm or less. When the predetermined distance is satisfied, as described above, the electrodes can be induction heated without damaging the laminate.

[0057] 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.

[0058] In addition, physical collision between the gripper and the heat press unit can be prevented through the first heat press step and the second heatless step, which will be described later.

[0059] 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 means 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 be diffused throughout the laminate.

[0060] The heat transferred to a portion of the laminate during the waiting step can be transferred to the entire laminate. In this manner, by intentionally halting induction heating of the laminate for a predetermined time before performing the heat pressing step (stopping induction heating of the laminate for a predetermined time), the heat transferred to the laminate by induction heating can be uniformly diffused throughout the laminate.

[0061] 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.

[0062] In one embodiment of the present invention, the waiting step may be carried out for 3 seconds or more and 60 seconds or less, preferably 5 seconds or more and 45 seconds or less, more preferably 10 seconds or more and 40 seconds or less.

[0063] 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 uniformly 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 unlikely to be 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 induction heating.

[0064] The waiting time may vary depending on the time and temperature range to which the laminate is heated in the subsequent heat pressing step.

[0065] 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 techniques commonly used in the art. For example, the method 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 process of moving the separator while covering the first or second electrode placed on the separator may be performed by moving the stack table left and right, moving the separator left and right, or rotating the stack table.

[0066] In the zigzag stacking method, a holding mechanism can grip the stack to maintain alignment of the stack while the first electrode, the second electrode, and the separator are stacked.

[0067] In this specification, the term "holding mechanism" refers to a component 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 press stage.

[0068] 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.

[0069] 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 direction of the lamination axis. The heat-pressing step may be performed by a heat press unit, which will be described later.

[0070] 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 relative to each other in the direction of the lamination axis to apply surface pressure to the laminate; and heating the laminate.

[0071] The pair of pressure blocks may be a lower plate and an upper plate facing the lower plate.

[0072] 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 direction of the lamination axis to apply surface pressure to the laminate; and heating the laminate by a separately provided press heater.

[0073] That is, the press heater may be included in the pressurizing block or may be provided as a separate component.

[0074] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include releasing the gripper before the heat pressing step.

[0075] That is, the step of releasing the grip of the grippers may include the steps of: stopping the grippers from applying pressure to the upper surface of the stack; and moving the grippers away from the stack.

[0076] In addition, in the heat pressing step, the step of moving the laminate between a pair of pressure blocks including a press heater may include not only moving the laminate itself but also moving the laminate together with the stack table while being 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.

[0077] 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 heat pressing step may involve heating and pressing the laminate 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 heat pressing step may involve heating and pressing the laminate at a temperature of 65°C to 85°C and a pressure of 3 MPa to 5.5 MPa for 7 to 25 seconds.

[0078] When the above conditions are met and heating and pressure are applied, 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.

[0079] In one embodiment of the present invention, the heat pressing step is not performed while the induction heating step is performed.

[0080] 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.

[0081] In a method for manufacturing an electrode assembly according to an embodiment of the present invention, an induction heating step and a heat pressing step may be sequentially performed, and a waiting step may be additionally performed between the induction heating step and the heat pressing step.

[0082] <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.

[0083] For reference, a semi-finished product state in which a first electrode, a separator, and a second electrode are repeatedly stacked can be expressed as a laminate, and a separate component can be divided into an electrode assembly by performing a separator surrounding process on the semi-finished product.

[0084] The electrode assembly manufacturing apparatus includes an induction heating unit. The induction heating unit of the electrode assembly manufacturing apparatus of the present invention performs the induction heating step described above. That is, when using the electrode assembly manufacturing apparatus of the present invention, a laminate including a first electrode, a separator, and a 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 deviations in separator permeability, separator thickness variation, 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. In addition, an electrode assembly with increased energy density per unit volume can be manufactured.

[0085] 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.

[0086] In one embodiment of the present invention, the induction heating unit may include an induction heating coil and may be a gripper that grips the laminate to transfer the laminate to the heat press unit. That is, in one embodiment of the present invention, the induction heating unit may be a gripper that grips the laminate to transfer the laminate to the heat press unit. The gripper may include an induction heating coil. As described above, the induction heating coil may be built into the gripper or installed outside the gripper. When the gripper serves as the induction heating unit, it is possible to save process space for installing the induction heating unit and to shorten process time by performing induction heating during transfer. The gripper may perform the function of gripping the laminate while transferring the laminate from the stack table to the heat press unit.

[0087] In one embodiment of the present invention, the induction heating unit may be provided separately from the gripper. That is, in one embodiment of the present invention, a gripper may be further included between the stack table and the induction heating unit to grip and transfer the laminate, and the induction heating unit may induction heat the laminate while gripping it with the gripper. The gripper may then transfer the induction-heated laminate to the heat press unit while gripping it, thereby allowing the laminate to be transferred without unnecessary gripping or unraveling in adjacent steps.

[0088] In one embodiment of the present invention, the induction heating unit may be installed 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 separate the induction heating device from the laminate.

[0089] In this case, as described above, there is an advantage that it can be easily applied even when the thickness of the laminate is thick, and it can also be used when the electrode tab is induction heated.

[0090] In this specification, the term "unit" refers to an interface that performs a specific function within an electrode assembly manufacturing apparatus.

[0091] The induction heating coil of the electrode assembly manufacturing apparatus according to an embodiment of the present invention may be in contact with the laminate or may be spaced a predetermined distance apart, which 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.

[0092] The advantages of the induction heating coil being in contact with the laminate and the advantages of the induction heating coil being spaced a predetermined distance from the laminate are the same as those described in the method of manufacturing the electrode assembly.

[0093] In one embodiment of the present invention, the induction heating unit may include an induction heating coil and an induction heating plate.

[0094] The induction heating coil may be included in an induction heating plate made of a non-conductive material. The induction heating plate may include an AC generator for providing AC to the induction heating coil and may also function to protect the induction heating coil. The use of a non-conductive material as the material of the induction heating plate prevents induced current from the induction heating coil from being generated in the induction heating plate.

[0095] The induction heating plate may be a mold made of a non-conductive material, which may be, but is not limited to, epoxy.

[0096] The induction heating coil and the induction heating plate may also be formed as a single set.

[0097] The induction heating unit may include an AC generator, but is not limited thereto, and any means capable of generating an electromagnetic induction phenomenon in the induction heating coil may be used.

[0098] 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 a surface of the laminate and sets an induction heating temperature for the laminate according to the measured temperature distribution, or determines whether to interrupt induction heating of the laminate based on the induction heating temperature and an induction heating time for the laminate.

[0099] The control unit can also adjust the induction heating time for the laminate.

[0100] That is, the control unit may set a condition for performing the induction heating step and a condition for performing the waiting step, and the above-described method for manufacturing an electrode assembly may be applied to each of the conditions.

[0101] In one embodiment of the present invention, the heat press unit may be composed of a pair of pressure blocks, and the pair of pressure blocks may be moved in directions opposite to each other to apply surface pressure to the laminate.

[0102] The heat press unit includes a pair of pressure blocks and a press heater for heating the pressure blocks. The pair of pressure blocks move toward each other while the press heater heats the pressure blocks, thereby applying surface pressure to the laminate placed between the pressure blocks.

[0103] In this case, the pair of pressurizing blocks may include press heaters therein.

[0104] In another embodiment of the present invention, the heat press section may be separable into two heat press sections, i.e., it may include a first heat press section and a second heat press section.

[0105] Referring to FIGS. 7(a) and 7(b), 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 grip and press 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.

[0106] Dividing the heat press into two sections as described above can prevent the heated laminate from being cooled during transport, which can prevent the adhesive strength between the layers inside the laminate from being lost.

[0107] 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.

[0108] On the other hand, in an embodiment of the present invention, the electrode assembly may have a rated capacity of 50 Ah to 200 Ah, preferably 50 Ah to 150 Ah, and more preferably 60 Ah to 140 Ah.

[0109] The electrode assembly may have a ratio of total length to total width of 5 to 10, preferably 5 to 8. Specifically, the electrode assembly may have a total length of 400 mm to 600 mm and a total width of 50 mm to 150 mm, preferably a total length of 500 mm to 600 mm and a total width of 50 mm to 100 mm.

[0110] An embodiment of the present invention is characterized in that after the electrode assembly is completed by assembling the laminates on a lamination table, a first press unit including an induction heater and a second press unit that heats and pressurizes the induction-heated electrode assembly are included. In particular, in the case of a large electrode assembly such as the above-mentioned electrode assembly, if it is heated by a direct contact method, significant temperature deviations may occur at various positions within the electrode assembly, particularly between the outermost portion of the electrode assembly and the center of the electrode assembly. However, when the embodiment of the present invention is applied to a large electrode assembly, it has the advantage of being able to heat the entire electrode assembly uniformly regardless of its position within the electrode assembly, even if the electrode assembly is thick.

[0111] In one embodiment of the present invention, the stack table may include a table body on which the stacked material is placed, and a drive unit for driving the table body. The table body may include a stack table heater that can heat the stacked material to a predetermined temperature when the stacked material is placed on the table body.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] In one embodiment of the present invention, the first electrode stack unit includes a first vacuum head that vacuum-sucks the first electrode placed on the first electrode placement table, and the first electrode can be moved from the first electrode placement table to the stack table by the first electrode stack unit.

[0117] The second electrode stacking unit may include a second vacuum head that vacuum-sucks the second electrode placed on the second electrode placing table, and the second electrode can be moved from the second electrode placing table to the stack table by the second electrode stacking unit.

[0118] In one embodiment of the present invention, the first electrode may be a positive electrode and the second electrode may be a negative electrode.

[0119] In one embodiment of the present invention, the first electrode may be a negative electrode and the second electrode may be a positive electrode.

[0120] In one embodiment of the present invention, a current collector, an active material, a conductive material, and the like used in the positive electrode and the negative electrode may be any material known in the art without limitation, and a method for manufacturing the positive electrode and the negative electrode may be any method known in the art without limitation.

[0121] In one embodiment of the present invention, the separation membrane may be any separation membrane known in the art without limitation, and the method for manufacturing the separation membrane may be any method known in the art without limitation. However, in one embodiment of the present invention, the separation membrane 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.

[0122] In one embodiment of the present invention, the particulate binder resin may include one or more selected from the group consisting of fluorine-based polymers, acrylic polymer particles, acrylic polymer particles, and acrylic polymer hybrid polymer particles.

[0123] 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 of these.

[0124] In one embodiment of the present invention, the inorganic particles may be, but are not limited to, Al2O3.

[0125] The inclusion of the organic / inorganic composite porous coating layer makes it possible to manufacture an electrode assembly with enhanced adhesion between the electrodes and the separator by applying the induction heating step and heat pressing step described in the electrode assembly manufacturing method and / or electrode assembly manufacturing apparatus.

[0126] Hereinafter, 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, assuming that the electrode assembly of the present invention is stacked in a zigzag pattern.

[0127] Fig. 1 is a cross-sectional view illustrating a process flow of an electrode assembly manufacturing apparatus according to an embodiment of the present invention, and Fig. 2 is a plan view illustrating the process flow of an electrode assembly manufacturing apparatus according to an embodiment of the present invention. For convenience, Fig. 1 omits the holding mechanism 170, heat press unit 180, and induction heating unit 190 shown in Fig. 2, and Fig. 2 omits the separator supply unit 120 shown in Fig. 1.

[0128] 1 to 3, 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 supplied to the stack table 110 while being heated in the first electrode supply unit 130 and the second electrode supply unit 140, respectively.

[0129] 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. As the separation membranes 14 fold, one of the first electrodes 11 and the second electrodes 12 is alternately inserted into spaces (between the separation membranes). 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.

[0130] 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.

[0131] More specifically, the first electrode supply unit 130 may include a first electrode mounting table 131, a first electrode heater 132 (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 132 (not shown) is selectively applicable.

[0132] The second electrode supply unit 140 may also include a second electrode mounting table 141, a second electrode heater 142 (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 142 (not shown) is selectively applicable.

[0133] 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 vacuum head 151, a first head heater 152 (not shown), and a first moving unit 153. In addition, 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 vacuum head 161, a second head heater 162 (not shown), and a second moving unit 163.

[0134] 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.

[0135] 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. Additionally, 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.

[0136] The electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention further includes an induction heating unit 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 or not the induction heating unit 190 is operated. As a result, the electrode assembly 10 shown in FIG. 3 can be finally manufactured.

[0137] FIG. 3 is a cross-sectional view illustrating an example of an electrode assembly manufactured through an electrode assembly manufacturing method and an electrode assembly manufacturing apparatus according to an embodiment of the present invention.

[0138] Referring to FIG. 3, the electrode assembly 10 may have a configuration in which separators are stacked while being folded in a zigzag shape, and first electrodes or second electrodes are inserted into spaces between the separators and stacked while being alternately inserted.

[0139] In this case, the electrode assembly 10 may be provided in a form in which the outermost periphery of the laminate is surrounded by the separator 14. However, the configuration of the electrode assembly 10 is not limited to the example shown in FIG.

[0140] 4 and 5 are diagrams showing the operation process of the induction heater according to the present invention, and show the steps after stacking.

[0141] Specifically, FIG. 4 illustrates a case where the induction heating unit 190 is a gripper 51. The gripper 51 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, a standby process (step) may be performed in which the induction heating of the laminate S is stopped and the laminate S is allowed to wait for a predetermined time. In this case, the conditions for the standby process may be set by a control unit (not shown).

[0142] FIG. 5 shows another example of induction heating, in which the laminate S is induction heated using an induction heating unit 190 provided separately from the gripper 51. In this case, the laminate S is transferred to the induction heating unit 190 and then induction heated. After the induction heating is completed, 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 predetermined time. In this case, the conditions for the waiting process may 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 after being removed from the induction heating unit 190, as shown in FIG.

[0143] Preferably, the induction heating unit 190 may perform induction heating while the laminate S is gripped by the gripper 51. That is, the gripper 51 transfers the laminate S from the stack table 110 to the induction heating unit 190 and does not release the grip while induction heating is being performed. Once induction heating is completed, the laminate S is transferred by the gripper 51 to the heat press unit 180, where it can be heated and pressed by the heat press unit 180, as shown in FIG. 4. In this way, it is possible to prevent the laminate S from being gripped and released unnecessarily repeatedly.

[0144] FIG. 6 illustrates an exemplary induction heating unit according to an embodiment of the present invention. Referring to FIG. 6, an induction heating unit 190 may include an induction heating coil 191 and an induction heating plate 192. More specifically, induction heating coils 191a and 191b may be embedded in induction heating plates 192a and 192b. The induction heating coil 191 may have a U-shape. The induction heating coils 191a and 191b may face each other, and the specific arrangement of the induction heating coil 191 may be, but is not limited to, the arrangement shown in FIG. 6.

[0145] When an AC current is applied to the induction heating coil 191, an induction current can be generated in the metallic electrodes in the electrode assembly, and the electrodes are heated by the induction current. Therefore, induction heating can be performed by targeting electrodes arranged in a specific layer in the electrode assembly.

[0146] The present invention is characterized in that, in the heat pressing step in which the electrode assembly is heated and pressurized, the electrodes disposed in the center of the electrode assembly, which are particularly vulnerable to heat, are targeted and pre-heated by induction heating before the heat pressing step.

[0147] 7 shows the configuration of the heat press unit 180. In particular, the heat press unit 180 is shown to include a first heat press unit 50 and a second heat press unit 60.

[0148] FIG. 7(a) is a perspective view showing the first heat press unit 50, and FIG. 7(b) is a perspective view showing the second heat press unit 60. As shown in FIG.

[0149] 7(a), the first heat press unit 50 may apply heat and pressure to the laminate S while it is fixed by 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.

[0150] 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 fixes the stack S. Here, the length x of the stack S refers to the longest part from one end to the other end of the stack S, the height y refers to the distance in the stacking direction of the stack S, and the width z refers to the distance across the top surface of the stack S.

[0151] 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.

[0152] Thereafter, the pair of first pressure blocks 50a and 50b move in opposite directions to heat and pressurize the laminate S. The electrodes and separators in the electrode assembly are stably bonded together by the heat and pressure.

[0153] The first heat press unit 50 may be a component that prevents the induction-heated electrode assembly from being cooled while it is moving, and may be provided as an optional component, i.e., may be omitted in some cases.

[0154] In particular, the method for manufacturing an electrode assembly of the present invention includes induction heating the laminate and then performing a heat pressing process to heat and press the laminate. When the laminate is induction heated, the laminate is uniformly heated throughout, allowing a predetermined adhesive strength to be developed between the separator and the electrode throughout the entire laminate. As a result, the first heat pressing operation, which is a kind of temporary bonding step, can be omitted.

[0155] In addition, in the first heat press operation, the gripper grips the laminate and the pressure block directly presses the part of the laminate that is not fixed by the gripper's fixed part. However, by omitting the first heat press operation, it is possible to obtain the advantage that no press marks are left on the laminate by the first heat press operation.

[0156] 7(b), the second heat press unit 60 may finally heat and press 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 that move in opposite directions 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 have pressure surfaces that are entirely flat and contact the laminate S to apply pressure.

[0157] 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.

[0158] <Electrode assembly> In this specification, the "outermost portion of the electrode assembly" refers to the uppermost or lowermost position in the stacking direction of the stack.

[0159] In addition, in this specification, the "middle of the electrode assembly" refers to a position corresponding to a middle portion between the uppermost position and the lowermost position in the stacking direction of the stacked stacks based on the stacking axis.

[0160] One embodiment of the present invention provides an electrode assembly including a first electrode, a separator, and a second electrode manufactured by the electrode assembly manufacturing method and / or the electrode assembly manufacturing apparatus according to the present invention. That is, the electrode assembly may be stacked by a zigzag stacking method.

[0161] However, the electrode assembly may have a laminate and folding (L&F) structure in which the electrodes and separator are wound, or a stacking and laminate (S&L) structure in which the electrodes and separator are sequentially stacked. That is, the present invention is applicable to various types of electrode assemblies because it adds a process of heating and pressurizing the electrode assembly after completing the electrode assembly to improve the adhesive strength between the electrodes and separator within the electrode assembly.

[0162] In one embodiment of the present invention, the electrode assembly is compressed while being heated, thereby increasing the energy density per unit volume. That is, the volume of the electrode assembly is reduced by applying pressure while being heated, compared to when the electrode and separator are simply stacked and then packaged.

[0163] In particular, the reduction in volume of the electrode assembly may be achieved through the separator. In this specification, the separator being compressed after zigzag stacking means that the separator of the electrode assembly is compressed compared to the separator before compression.

[0164] That is, in one embodiment of the present invention, the compressibility of the separator located at the outermost portion of the electrode assembly may be greater than the compressibility of the separator located at the middle portion of the electrode assembly, and the difference in compressibility may be 3%p (Percentage Point) or less, preferably 2%p or less, and more preferably 1.5%p or less.

[0165] In one embodiment of the present invention, the separator located at the outermost portion of the electrode assembly may have a compressibility of 3% to 8%, preferably 4% to 8%.

[0166] In one embodiment of the present invention, the separator located in the middle of the electrode assembly may have a compressibility of 3% to 8%, preferably 4% to 8%.

[0167] In one embodiment of the present invention, the separator located at the outermost portion of the electrode assembly may have a compressibility of 3% to 8%, preferably 4% to 8%, and the separator located at the middle portion of the electrode assembly may have a compressibility of 3% to 8%, preferably 4% to 8%.

[0168] The compressibility of the separator can be calculated based on the difference between the thickness of the separator supplied (raw thickness, before processing) and the thickness of the separator after the electrode assembly is completed (after processing).

[0169] In one embodiment of the present invention, the thickness of the separator located in the middle of the electrode assembly may be 1 to 1.09 times, preferably more than 1 to 1.09 times, more preferably more than 1 to 1.05 times, and more preferably more than 1 to 1.03 times, the thickness of the separator located at the outermost edge of the electrode assembly.

[0170] That is, in one embodiment of the present invention, the thickness of the separator located at the outermost portion of the electrode assembly may be thinner than the thickness of the separator located at the middle portion of the electrode assembly, and the thickness of the separator located at the middle portion of the electrode assembly may be 1.09 times or less the thickness of the separator located at the outermost portion of the electrode assembly.

[0171] In one embodiment of the present invention, the deviation of the thickness of the separator of the electrode assembly may be 9% or less, preferably 5% or less, and more preferably 3% or less.

[0172] The electrode assembly according to the present invention is manufactured by heating and pressurizing a laminate (unfinished electrode assembly) in which electrodes and separators are stacked. Since the thickness deviation between the outermost separator of the electrode assembly and the intermediate separator of the electrode assembly is the largest, the thicknesses of the outermost separator of the electrode assembly and the intermediate separator of the electrode assembly can be compared to determine whether the thickness deviation of the separator of the electrode assembly falls within the above-mentioned numerical range.

[0173] In one embodiment of the present invention, the electrode assembly satisfies the formula 1. Specifically, the formula 1 satisfies 1.02E A ≦E B , preferably 1.03E A ≦E B That is, the separator and electrodes are compressed during the heating and pressurizing process, increasing the energy density (Wh / L). Here, energy density refers to power per volume.

[0174] The energy density is calculated by disassembling the electrode assembly, determining the energy densities at the outermost and middle positions of the electrode assembly, and then averaging the values.

[0175] As described above, the electrode assembly according to the embodiment of the present application has a uniform separator thickness, which results in uniform performance and superior voltage resistance.

[0176] In one embodiment of the present invention, the separator located at the outermost portion of the electrode assembly may have a higher compressibility than the separator located at the middle portion of the electrode assembly.

[0177] That is, the electrode assembly according to the present invention has a uniform separator thickness, so that the performance is uniform and the withstand voltage is also superior.

[0178] In one embodiment of the present invention, the electrode assembly may have a withstand voltage of 1.5 kV or more.

[0179] In one embodiment of the present invention, the air permeability of the separator located in the middle of the electrode assembly may be 80 sec / 100 ml to 120 sec / 100 ml, preferably 80 sec / 100 ml to 110 sec / 100 ml, and more preferably 85 sec / 100 ml to 100 sec / 100 ml.

[0180] In addition, in one embodiment of the present invention, the separator located at the outermost portion of the electrode assembly may have an air permeability of 80 sec / 100 ml to 120 sec / 100 ml, preferably 80 sec / 100 ml to 110 sec / 100 ml, and more preferably 85 sec / 100 ml to 100 sec / 100 ml.

[0181] According to one embodiment of the present invention, the deviation of the air permeability of the separator located in the middle of the electrode assembly from the air permeability of the separator located at the outermost portion of the electrode assembly may be 2 sec / 100 ml to 15 sec / 100 ml, preferably 2 sec / 100 ml to 10 sec / 100 ml.

[0182] Furthermore, the description of the electrode assembly manufacturing apparatus according to the present invention and the configuration of the manufacturing apparatus can also be applied to the manufacturing method according to the present invention and the electrode assembly manufactured by the manufacturing method according to the present invention. [Example]

[0183] 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 is obvious to those having ordinary skill 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.

[0184] <Electrode assembly manufacturing> 1) Example 1 Nineteen positive electrodes, 20 negative electrodes, and a separation membrane were supplied to the stack table from the positive electrode supply unit, negative electrode supply unit, and separation membrane supply unit, respectively.

[0185] More specifically, the positive electrode and the negative electrode were supplied in the form of cut positive electrode sheets and negative electrode sheets, respectively, and the separator was supplied in the form of a separator sheet, and then the stack table was rotated to fold the supplied separator, thereby stacking the positive electrode, the negative electrode, and the separator.

[0186] At this time, the positive electrode and the negative electrode were supplied by using an electrode stack unit including a vacuum head, an electrode non-contact heater, and a moving unit.

[0187] At the same time, the positive electrode or negative electrode stacked on the top of the stack table was stacked using a holding mechanism, resulting in a stack (electrode assembly) in which the positive electrode, negative electrode, and separator were stacked in a zigzag pattern.

[0188] Next, the laminate was induction heated for 15 seconds in an induction heating unit including a U-shaped induction heating coil (induction heating step). After that, the laminate was left to stand for 15 seconds (standby step). After the standby step, the laminate was heated and pressed for 15 seconds at a temperature of 70°C and a pressure of 3.5 MPa (heat pressing step) to produce the electrode assembly of Example 1.

[0189] During the manufacturing process, the change in surface temperature of the laminate S was measured. Specifically, the surface of the laminate S was divided into a heated portion heated by the U-shaped induction heating coil and an unheated portion not heated by the U-shaped induction heating coil, and the temperature change was measured for each portion. The results are shown in Figure 8.

[0190] The above-described aspects of the present invention can be applied to the process of manufacturing the electrode assembly.

[0191] Next, the adhesive force pattern of the electrode assembly of Example 1 was measured using an adhesive force measuring device, and the results are shown in Figure 9. Specifically, the adhesive force pattern of the electrode assembly was measured in the direction of the arrow in Figure 9.

[0192] From the results of Figure 8, it was confirmed that the temperature of the surface of the laminate can be increased when an induction heating process is performed. In particular, since induction heating is possible for electrodes that are not located on the outermost periphery of the laminate and are not in direct contact with each other, it was confirmed that temperature unevenness between the electrodes during the heat pressing process can be prevented.

[0193] In addition, it was confirmed from the results of Figure 8 that the temperature difference between the heated and unheated parts can be reduced when the waiting process is performed. As the temperature difference is reduced, it was confirmed that the adhesive strength pattern of the electrode assembly is uniform, as shown in Figure 9.

[0194] 2) Comparative Example 1 An electrode assembly of Comparative Example 1 was manufactured in the same manner as in Example 1, except that the induction heating and waiting processes were not performed.

[0195] <Experimental Example 1 - Evaluation of changes in thickness of separation membrane raw sheet and compression rate of separation membrane> The electrode assemblies of Example 1 and Comparative Example 1 were evaluated for thickness change of the separator sheet and compressibility of the separator.

[0196] Specifically, the thickness of the separator roll was measured before lamination, and then the electrode assemblies of Example 1 and Comparative Example 1 were disassembled. The separator located at the top (outermost) of the electrode assembly and the separator located at the midpoint (center) between the top and bottom of the electrode assembly were collected based on the lamination direction of the electrode assembly. The change in the thickness of the separator roll before and after the process was measured, and the results are shown in Table 1. The separator compressibility was also calculated from the change in thickness of the separator roll, and is shown in Table 1.

[0197] [Table 1]

[0198] As can be seen from Table 1, when the induction heating and waiting processes were not performed, the deviation in thickness of the separator sheet was large, and the thickness of the separator sheet was reduced more than necessary at the outermost periphery, while the deviation in thickness of the separator sheet was almost nonexistent at the center. That is, in Comparative Example 1, unlike Example 1, the deviation in thickness of the separator sheet was large depending on the position of the electrode assembly.

[0199] This means that it is difficult for the electrode assembly to have uniform performance regardless of the position of the electrode assembly. In other words, it was confirmed that the electrode assemblies manufactured using the manufacturing apparatus and method according to the present invention have uniform performance.

[0200] <Experimental Example 2 - Withstand Voltage Evaluation> The withstand voltage was evaluated for the electrode assemblies of Example 1 and Comparative Example 1. The results are shown in Table 2 below.

[0201] [Table 2]

[0202] As can be seen from Table 2, when the induction heating and standby steps were performed, the withstand voltage was superior to when the induction heating and standby steps were not performed. In other words, it was confirmed that the withstand voltage performance of Comparative Example 1 was inferior to that of Example 1.

[0203] <Experimental Example 3 - Evaluation of separation membrane air permeability> The electrode assemblies of Example 1 and Comparative Example 1 were disassembled, and the separation membranes corresponding to the midpoints between the upper and lower ends of the electrode assemblies in the stacking direction of the electrode assemblies were collected and cut to prepare separation membrane samples measuring 5 cm x 5 cm (width x length). The separation membrane samples were then washed with an organic solvent.

[0204] Thereafter, the air permeability of Example 1 and Comparative Example 1 was measured by measuring the time it took for 100 ml (or 100 cc) of air to pass through 1 square inch of the separator membrane at room temperature and a pressure of 0.05 MPa using a Toyoseiki Gurley type Densometer (No. 158) according to the Japanese Industrial Standard Gurley measurement method. For reference, three specimens of Example 1 were tested three times, and the results are shown as Examples 1-1 to 1-3.

[0205] The results are shown in Table 3 below.

[0206] [Table 3]

[0207] From the results in Table 3, it was confirmed that the top surface air permeability, bottom surface air permeability, and intermediate surface air permeability of the electrode assembly according to the present invention were 80 sec / 100 ml or more. In addition, the top surface air permeability, bottom surface air permeability, and intermediate surface air permeability of the electrode assembly according to the present invention did not exceed 120 sec / 100 ml. In other words, it was confirmed that the electrode assembly according to the present invention met the standards for management as a good electrode assembly.

[0208] It was also confirmed that the deviation in air permeability between the positions in Example 1 was less than 20 sec / 100 ml, which is controlled as a non-defective product, and it can be determined that the air permeability is substantially uniform when it is 10 sec / 100 ml or less.

[0209] On the other hand, in the case of Comparative Example 1, when compared with Example 1, no significant results were shown in the deviation of air permeability, but the top surface air permeability, bottom surface air permeability, and middle surface air permeability all showed values ​​of less than 80 sec / 100 ml, and it was determined that the safety was low. This is thought to be because the top, bottom, and middle surfaces of the laminate were not sufficiently heated because the laminate was only heat pressed without induction heating.

[0210] <Experimental Example 4 - Evaluation of separation membrane adhesion strength> Meanwhile, the adhesive strength of the electrode assembly of Example 1 was evaluated. After separating the electrode assembly of Example 1, the adhesive strength of the separated top, bottom, and middle surfaces was evaluated. The adhesive strength was measured between the separator and the positive electrode located at the top and bottom of the laminate. The adhesive strength was also measured between the separator and the positive electrode located at the middle of the laminate in the stacking direction.

[0211] The adhesive strength was measured by the following method.

[0212] The sample was attached to a glass slide so that the electrode was positioned on the adhesive surface of the glass slide, and then the glass slide with the sample attached was placed in an adhesion strength measuring device and a 90-degree peel test was performed at a speed of 100 mm / min according to the test method specified in ASTM-D6862.

[0213] The results are shown in Table 4 below.

[0214] [Table 4]

[0215] As shown in Table 4, the electrode assembly manufactured by induction heating showed almost uniform adhesive strength with the positive electrode at the top, bottom, and middle of the electrode assembly, ranging from 3.1 gf / 20 mm to 3.6 gf / 20 mm (0.030 N / 20 mm to 0.035 N / 20 mm).

[0216] From the above experimental examples, it was confirmed that the electrode assembly manufactured using the electrode assembly device and method of the present invention has excellent stability of the electrodes and separator, and has an appropriate level of air permeability that does not cause deformation of the separator.

[0217] It was also confirmed that an electrode assembly with excellent voltage resistance and uniform performance could be manufactured. [Explanation of symbols]

[0218] 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 100...Electrode assembly manufacturing equipment 110 Stack Table 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 132 First electrode heater 133 First electrode roll 134 First cutter 135 First conveyor belt 136 First electrode supply head 140...Second electrode supply section 141 Second electrode placement table 142 Second electrode heater 143 Second electrode roll 144 Second cutter 145 Second conveyor belt 146 Second electrode supply head 150 First electrode stack section 151 First vacuum head 152 First head heater 153 First moving part 160 Second electrode stack section 161 Second vacuum head 162 Second head heater 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 section 191 (191a, 191b) Induction heating coil 192 (192a, 192b) Induction heating plate S ···Laminate

Claims

1. A method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, a stacking step of 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; and a heat press step of heating and pressing the induction-heated laminate; A method for manufacturing an electrode assembly, comprising:

2. 2. The method of claim 1, wherein the induction heating step inductively heats the laminate using an induction heating coil.

3. The method further includes a transfer step of gripping the laminate with a gripper including an induction heating coil and transferring the laminate between the stacking step and the heat pressing step, The method of manufacturing an electrode assembly according to claim 1 , wherein the induction heating step is performed with the gripper during the transferring step.

4. The method further includes 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, The method of manufacturing an electrode assembly according to claim 1 , wherein the induction heating step is performed using an induction heating device.

5. the step of transferring the laminate to an induction heating device including an induction heating coil includes a step of gripping the laminate with a gripper and transferring it to the induction heating device; The method of manufacturing an electrode assembly according to claim 4 , wherein the induction heating step comprises inductively heating the laminate while the laminate is held by the gripper.

6. The method of manufacturing an electrode assembly according to claim 2, wherein the induction heating coil is in contact with the laminate or is spaced a predetermined distance from the laminate.

7. The method of manufacturing an electrode assembly according to claim 6 , wherein the predetermined distance is 15 mm or less.

8. 2. The method of claim 1, further comprising a waiting step of leaving the laminate in an atmospheric state for a predetermined time between the induction heating step and the heat pressing step.

9. The method of claim 8 , wherein the waiting step is performed for 3 seconds or more and 60 seconds or less.

10. 2. The method of claim 1, wherein the induction heating is performed for 1 to 60 seconds.

11. The induction heating step comprises: measuring the temperature distribution on the surface of the laminate; setting an induction heating temperature for the laminate according to the measured temperature distribution; and Induction heating the laminate based on the set induction heating temperature; The method for manufacturing an electrode assembly according to claim 1 , comprising:

12. 2. The method of claim 1, wherein the induction heating step heats the electrodes disposed at the center of the laminate more than the electrodes disposed at the top or bottom of the laminate.

13. An electrode assembly manufacturing apparatus for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, a stack table on which the first electrode, the separation membrane, and the second electrode are stacked to form a stack including the first electrode, the separation membrane, and the second electrode; a heat press unit for heating and pressing the laminate; and an induction heating section for induction heating the laminate before heating and pressing the laminate in the heat press section; An electrode assembly manufacturing apparatus comprising:

14. The electrode assembly manufacturing apparatus according to claim 13 , wherein the induction heating unit includes an induction heating coil and is a gripper that grips the laminate to transfer the laminate to the heat press unit.

15. The induction heating unit is 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; The electrode assembly manufacturing apparatus according to claim 13 , comprising:

16. The electrode assembly manufacturing apparatus according to claim 14 or 15, wherein the induction heating coil is in contact with the laminate or is spaced a predetermined distance from the laminate.

17. The electrode assembly manufacturing apparatus according to claim 16, wherein the predetermined distance is 15 mm or less.

18. a gripper for gripping and transferring the stack between the stack table and the induction heating unit; The electrode assembly manufacturing apparatus according to claim 13 , wherein the induction heating unit induction heats the laminated material while the laminated material is gripped by the gripper.

19. The electrode assembly manufacturing apparatus of claim 13 , wherein the induction heating unit is configured to apply more heat to an electrode disposed at a center of the laminate than to an electrode disposed at a top or bottom of the laminate.

20. measuring a temperature distribution on the surface of the laminate and setting an induction heating temperature for the laminate in accordance with the measured temperature distribution; The electrode assembly manufacturing apparatus of claim 13 , further comprising a control unit that determines whether to stop induction heating of the laminate based on the induction heating temperature and an induction heating time for the laminate.

21. An electrode assembly including a first electrode, a separator, and a second electrode, The electrode assembly is zigzag stacked, After the zigzag stacking, the electrode assembly is heated and pressurized; An electrode assembly that satisfies the following formula 1: [Formula 1] 1.02E Ａ ≦E Ｂ In the formula 1, E Ａ is the energy density Wh / L of the electrode assembly before heating and pressing, E Ｂ is the energy density Wh / L of the electrode assembly after heating and pressing.

22. 22. The electrode assembly of claim 21, wherein the compressibility of the separator located at the outermost portion of the electrode assembly is greater than the compressibility of the separator located at the middle of the electrode assembly, and the difference in compressibility is 3% p or less.

23. 22. The electrode assembly according to claim 21, wherein the electrode assembly has a total length of 400 mm to 600 mm and a total width of 50 mm to 150 mm.

24. 22. The electrode assembly of claim 21, wherein the separator located in the middle of the electrode assembly has an air permeability of 80 sec / 100 ml to 120 sec / 100 ml.

25. The electrode assembly according to claim 21 , wherein the deviation of the air permeability of the separator among the upper, middle, and lower surfaces is less than 20 sec / 100 ml.

26. The deviation in adhesive strength between the separator and either the first electrode or the second electrode is less than 3.6 gf / 20 mm (0.035 N / 20 mm), The electrode assembly of claim 21 , wherein one of the first electrode and the second electrode is a positive electrode.

27. 27. The electrode assembly of claim 21, wherein the electrode assembly is inductively heated before being heated and pressurized.

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