Electrode assembly, method for manufacturing the same, and manufacturing apparatus therefor

Abstract

The present invention is a method for manufacturing an electrode assembly including a first electrode, a separation membrane, and a second electrode, the method including: a stacking step of stacking a laminate including the first electrode, the separation membrane, and the second electrode on a stack table; an induction heating step of induction heating the laminate; and a heat press step of heating and pressurizing the induction heated laminate. At least one of the first electrodes of the laminate includes a first electrode tab, and at least one of the second electrodes of the laminate includes a second electrode tab. The method further includes an electrode tab induction heating step of induction heating at least one of the first electrode tab and the second electrode tab between the induction heating step and the heat press step.

Description

Technical Field

[0001] The present invention claims the benefit of the filing dates of Korean Patent Application No. 10-2023-0000716 filed with the Korean Intellectual Property Office on January 3, 2023, Korean Patent Application No. 10-2023-0056378 filed with the Korean Intellectual Property Office on April 28, 2023, and Korean Patent Application No. 10-2024-0000188 filed with the Korean Intellectual Property Office on January 2, 2024, and all of its contents are included herein.

[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 Art

[0003] Unlike primary batteries, secondary batteries are rechargeable and have been actively researched and developed in recent years due to their potential for miniaturization and increased capacity. As the technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source has been rapidly increasing.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries according to the shape of the battery case. The electrode assembly installed inside the battery case in a secondary battery is a power generation element capable of charge and discharge, which has a laminated structure of electrodes and a separator.

[0005] The electrode assembly can be generally classified into a jelly-roll type in which a separator is interposed between sheet-type positive and negative electrodes coated with active materials and wound, a stack type in which a large number of positive and negative electrodes are sequentially laminated with a separator interposed therebetween, and a stack-and-folding type in which unit cells of the stack type are wound with a long separation film.

[0006] Here, in a stack-and-fold type electrode assembly, the separation membrane is laminated while being folded in a zigzag shape, and the positive electrode, the separation membrane, and the negative electrode are laminated in such a form that an electrode of the positive electrode or the negative electrode is inserted between the folded separation membranes.

[0007] In this process, in order to bond the electrode and the separation membrane to each other, heat and pressure are applied to the laminate in which the positive electrode, the separation membrane, and the negative electrode are laminated. However, in order to bond the electrodes (positive electrode, negative electrode) and the separation membrane in the laminate by applying heat and pressure to the laminate, a large amount of time and energy are required.

[0008] In addition, when heat and pressure are applied to the laminate, there is a problem that heat and pressure cannot be uniformly applied regardless of the lamination positions of the electrodes and the separation membrane due to the difference in the lamination positions (lamination height) of the electrodes and the separation membrane in the laminate. That is, a problem occurs in that the adhesive force between the separation membrane and the electrode is not constant.

[0009] As a result, there is a problem that the performance of the electrode assembly becomes non-uniform.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention provides an electrode assembly, a method for manufacturing the same, and a manufacturing apparatus therefor, for solving problems caused by non-constant adhesive force.

Means for Solving the Problems

[0012] One embodiment of the present invention is a method for manufacturing an electrode assembly including a first electrode, a separation membrane, and a second electrode, the method including: a stacking step of stacking a laminate including the first electrode, the separation membrane, and the second electrode on a stack table; an induction heating step of induction heating the laminate; and a heat press step of heating and pressing the induction-heated laminate, at least one of the first electrodes of the laminate includes a first electrode tab, at least one of the second electrodes of the laminate includes a second electrode tab, and the method further includes an electrode tab induction heating step of induction heating at least one of the first electrode tab and the second electrode tab between the induction heating step and the heat press step.

[0013] One embodiment of the present invention is an electrode assembly manufacturing apparatus for manufacturing an electrode assembly including a first electrode, a separation membrane, and a second electrode, the apparatus including: a stack table on which a laminate including the first electrode, the separation membrane, and the second electrode is stacked; and a heat press unit for heating and pressing the laminate, at least one of the first electrodes of the laminate includes a first electrode tab, at least one of the second electrodes of the laminate includes a second electrode tab, the apparatus further includes an induction heating unit for induction heating the laminate while transferring the laminate from the stack table to the heat press unit; and an electrode tab induction heating unit for induction heating at least one of the first electrode tab and the second electrode tab before heating and pressing the laminate induction-heated by the induction heating unit with the heat press unit.

[0014] Finally, one embodiment of the present invention is an electrode assembly including a first electrode, a separation membrane, and a second electrode, wherein the electrode assembly is zigzag stacked, the separation membrane is compressed after the zigzag stacking, the compression ratio of the separation membrane located on the outermost periphery of the electrode assembly is larger than the compression ratio of the separation membrane located in the middle of the electrode assembly, and the compression ratio difference is 3%p or less.

Advantages of the Invention

[0015] The method for manufacturing an electrode assembly and the electrode assembly manufacturing apparatus according to an embodiment of the present application can shorten the time for manufacturing the electrode assembly.

[0016] The method for manufacturing an electrode assembly and the electrode assembly manufacturing apparatus according to an embodiment 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, so that an electrode assembly with uniform performance can be provided.

[0017] The electrode assembly according to an embodiment of the present application has the advantage that the deviation of the air permeability of the separation membrane due to position is small and the performance is uniform.

Brief Description of the Drawings

[0018]

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Embodiments for Carrying Out the Invention

[0019] Hereinafter, the present invention will be described in detail so that a person having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be embodied in various different forms and is not limited to only the configurations described herein.

[0020] In this specification, when a certain part “includes” a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components and may further include other components.

[0021] In one embodiment of the present invention, the electrode assembly can be laminated in such a form that the first electrode and the second electrode are alternately arranged between the separation membranes to be folded.

[0022] In this specification, laminating the first electrode and the second electrode alternately between the separation membranes to be folded is referred to as Zig Zag Stacking.

[0023] At this time, to explain more specifically the form in which the first electrode and the second electrode are alternately arranged between the separation membranes to be folded, the separation membrane to be folded can mean a separation membrane in a form where the separation membranes are laminated while overlapping in a zigzag manner. More specifically, the separation membrane is laminated in a zigzag manner while being folded in a form that alternately reciprocates between the left side and the right side of the lamination axis with respect to the lamination axis. And it means that the first electrode and the second electrode are laminated alternately between the laminated separation membranes. Here, the lamination axis means an imaginary axis that is parallel to the direction in which the first electrode, the separation membrane, and the second electrode are laminated and passes through the center of the laminate in which the electrode and the separation membrane are laminated.

[0024] That is, the meaning that the first electrode and the second electrode are alternately arranged between the separation membranes means that the separation membranes are laminated in the direction of the lamination axis while overlapping in a zigzag shape, and the first electrode and the second electrode are respectively inserted one by one alternately into the space (between the separation membranes) generated while the separation membranes overlap.

[0025] <Method for manufacturing an electrode assembly> One embodiment of the present invention provides a method for manufacturing an electrode assembly including a first electrode, a separation membrane, and a second electrode.

[0026] The method for manufacturing an electrode assembly according to the present invention includes a step of induction heating the laminate between a stacking step which is a step of manufacturing the laminate and a heat press step which is a step of heating and pressing the laminate, and a step of induction heating the electrode tab portion of the induction-heated laminate.

[0027] The heat press step includes a lower plate on which an electrode assembly to be heated and pressed is placed and 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.

[0028] In the heat press step of heating and pressing the electrode assembly, the electrodes located at the outermost contours (the uppermost and lowermost ends of the laminate) of the laminate are physically in direct contact with the lower plate and the upper plate, so more heat and pressure are transmitted than the electrodes at the intermediate positions of the laminate. This is because the heat press step heats while pressing in a state of being physically in contact with the uppermost and lowermost ends of the laminate.

[0029] That is, in the heat press step, the electrodes in the laminate may be heated at different temperatures depending on their positions, and the electrodes and the separation membrane may have different adhesive forces depending on their positions. As a result, a problem may occur that the performance of the electrode assembly becomes non-uniform depending on the position.

[0030] Therefore, the method for manufacturing an electrode assembly according to the present invention heats a large amount of heat in a local region, particularly the central portion, in the laminate by an induction heating step. Then, the heat applied to the local region is diffused to the entire electrode assembly. And, by heating and pressing the electrode assembly in the subsequent heat press step, the electrode assembly is heated uniformly throughout.

[0031] In this process, since the electrode tabs included in the laminate are thinner than the electrodes and the separation film, after the induction heating step, the temperature of the electrode tab portion drops faster than other portions. As a result, there is a possibility that the problem of non-uniform heating occurs in the vicinity of the electrode tabs even when the heat press step is performed after the induction heating step. The present invention additionally performs a step of induction heating the electrode tab portion between the induction heating step and the heat press step, and by heating and pressing the electrode assembly in the heat press step, the electrode assembly is heated more uniformly throughout.

[0032] Thereby, the air permeability deviation of the separation film inside the electrode assembly manufactured through the heat press step is reduced, the deviation of the adhesive force between the electrode and the separation film is reduced, and an electrode assembly having uniform performance can be manufactured.

[0033] In one embodiment of the present invention, the stacking step may include a step of supplying the first electrode to a stacking table; a step of supplying the second electrode to the stacking table; and a step of supplying the separation film to the stacking table.

[0034] In this specification, "induction heating" is heating an object by utilizing the electromagnetic induction phenomenon. In this way, Joule heat is generated in the object by the induced current generated in the object by the electromagnetic induction phenomenon. Therefore, induction heating is a heating method capable of locally heating an object at a predetermined distance from the heating element, compared to a direct heating method of directly contacting the object for heating.

[0035] To perform the induction heating, a coil can be used, which can be defined as an "induction heating coil". The induction heating method has the advantage of being easy to adjust the heat and time applied to the object to be heated. Also, non-contact heating is possible, and it does not damage the object to be heated.

[0036] In this specification, the "induction heating step" can be meant to locally heat the laminate by utilizing the electromagnetic induction heating phenomenon. The laminate to be locally heated may be an electrode disposed at the center of the laminate. When using the direct heating method, the uppermost or lowermost electrode of the electrode assembly may be heated more than the central electrode of the electrode assembly. However, the method for manufacturing an electrode assembly according to an embodiment of the present invention can finally heat the electrode assembly uniformly by first selectively heating the center part of the electrode assembly by the induction heating method and then heating the electrode assembly by the direct heating method in the subsequent heat press step.

[0037] In this specification, the "electrode tab induction heating step" is distinguished from the induction heating step in that, similar to the induction heating step, by utilizing the electromagnetic induction heating phenomenon, the object to be heated is the electrode tab portion included in the electrode of the laminate. That is, the object to be locally heated can be the electrode tab. Since the electrode tab is relatively very thin compared to the electrode and the separation film, there is a possibility that the surface temperature may first decrease after the induction heating step. For this reason, there is a possibility that the temperature of the electrode tab portion becomes relatively non-uniform in the heat press step. However, the method for manufacturing an electrode assembly according to an embodiment of the present invention can heat the electrode assembly uniformly in the subsequent heat press step by further heating the relatively cooled electrode tab before performing the heat press step after the induction heating step by the electrode tab induction heating method.

[0038] In one embodiment of the present invention, the electrode tab induction heating step may be to induction heat at least one of the first electrode tab and the second electrode tab using an induction heating coil.

[0039] In one embodiment of the present invention, the induction heating coil may be in contact with or separated from at least one of the first electrode tab and the second electrode tab by a predetermined distance. When the induction heating coil is in contact with the electrode tab (the distance between the electrode tab and the induction heating coil is 0 mm), heat can be transferred maximally. Therefore, there is an advantage that the temperature of the electrode tab can be increased even when induction heating is performed for a short time.

[0040] Also, when the induction heating coil is separated from the electrode tab by a predetermined distance, there is an advantage that the temperature of the electrode tab can be increased without damaging the electrode tab by the heat generated by the induction heating coil.

[0041] 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 more than 0 mm and 15 mm or less, 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 distance is satisfied, as described above, the electrode tab can be induction heated without damaging the electrode tab.

[0042] In one embodiment of the present invention, the electrode tab induction heating step may be performed for 1 second to 60 seconds. Preferably, it may be performed for 5 seconds to 40 seconds, and more preferably for 10 seconds to 30 seconds. However, the electrode tab induction heating time can be selected in consideration of the induction heating temperature in the induction heating step, the degree to which the electrode assembly is unevenly heated in the heat press step, and the like.

[0043] In one embodiment of the present invention, in the electrode tab induction heating step, the electrode tab can be heated at a temperature of 40°C or higher and 90°C or lower, preferably 50°C or higher and 80°C or lower. When the electrode tab is induction heated within the temperature range, the electrode tab can be heated without being damaged.

[0044] In one embodiment of the present invention, in the induction heating step, a part of the laminate can be induction heated, and the heat can be diffused throughout the laminate to heat the entire laminate.

[0045] In one embodiment of the present invention, the step of induction heating can induction heat the first electrode or the second electrode of the laminate. More specifically, in one embodiment of the present invention, the step of induction heating can induction heat the first electrode or the second electrode disposed at the center of the laminate. In the heat press step, relatively less heat can be applied to the first electrode or the second electrode disposed at the center of the laminate compared to the first electrode or the second electrode disposed at the outermost periphery of the laminate. However, heat can be applied to the first electrode or the second electrode disposed at the center of the laminate first through the induction heating step, and then by performing the heat press step, heat can be uniformly applied to the entire laminate.

[0046] In this specification, in addition to induction heating only a partial region (local region) of the surface of the laminate, it may also include induction heating the entire surface of the laminate. However, even if only a partial region is induction heated, the object of the present invention can be achieved. Also, it is distinguished from heat press in that no pressure is applied to the laminate.

[0047] In one embodiment of the present invention, the induction heating step may be performed for 1 second to 60 seconds, preferably 5 seconds to 40 seconds, more preferably 10 seconds to 30 seconds. The induction heating time may be selected in consideration of the degree to which the electrode assembly is non-uniformly heated in the heat press step.

[0048] In one embodiment of the present invention, the induction heating step may be to induction heat the laminate using an induction heating coil.

[0049] According to one embodiment of the present invention, the method for manufacturing an electrode assembly may include a step of transferring the laminate to a heat press step after the stacking step. In the transferring step, in order to transfer the laminate, the laminate can be gripped by a gripper.

[0050] The gripper can hold the grip on the laminate in the heat press step.

[0051] According to one embodiment of the present invention, the method for manufacturing an electrode assembly can inductively heat the laminate while transferring the laminate from the stack table to the heat press section.

[0052] More specifically, in one embodiment of the present invention, the induction heating step further includes a transfer step of gripping the laminate with a gripper including an induction heating coil between the stacking step and the heat press step and transferring the laminate, and the induction heating step can be executed by the gripper during the transfer step.

[0053] More specifically, in one embodiment of the present invention, the induction heating step may include a step of gripping the laminate with a gripper including an induction heating coil; a step of transferring the gripped laminate to the heat press step; and a step of inductively heating the laminate with the induction heating coil of the gripper while transferring the laminate.

[0054] That is, by incorporating the induction heating coil into the gripper or attaching it 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.

[0055] On the other hand, 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 press step, and the induction heating step may be executed by the induction heating device. As long as the induction heating device can execute induction heating, a method commonly used in the art can be used.

[0056] 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 induction heating the laminate with the induction heating device; More specifically, the induction heating step may be to perform induction heating while gripping the laminate with the gripper. In this way, after the laminate is gripped by the gripper, it can be transferred to the heating and pressing steps without unnecessary pause through the induction heating step. That is, it is possible to avoid repeatedly gripping and releasing the laminate between adjacent steps.

[0057] That is, the induction heating coil may not be mounted inside or outside the gripper, and even when a separate induction heating device from the gripper includes an induction heating coil. When using a separate induction heating device, there is an advantage that the induction heating step can be performed even when the thickness of the laminate including the electrode and the separation film increases.

[0058] Also, as in the present invention, when using a separate induction heating device, the electrode tab portion protruding from the electrode can be additionally heated by the induction heating device, so that the temperature difference between the electrode tab and the electrode can be reduced.

[0059] In one embodiment of the present invention, the induction heating step can heat the laminate at a temperature of 40°C or higher and 90°C or lower, preferably 50°C or higher and 80°C or lower. When the laminate is induction heated within this temperature range, the laminate can be heated without damaging the electrodes and the separation film inside the laminate.

[0060] In one embodiment of the present invention, the induction heating coil may be in contact with the laminate or separated from it by a predetermined distance.

[0061] When the induction heating coil is in contact with the laminate (the distance between the laminate and the induction heating coil is 0 mm), heat can be transferred maximally. Therefore, even if induction heating is performed for a short time, the internal temperature of the laminate can be increased, which has the advantage of being able to raise the internal temperature of the laminate.

[0062] Also, when the induction heating coil is separated from the laminate by a predetermined distance, there is an advantage that the internal temperature of the laminate can be increased while the laminate is not damaged by the heat generated by the induction heating coil.

[0063] 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 more than 0 mm and 15 mm or less, 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 distance is satisfied, as described above, the electrodes can be induction heated without damaging the laminate.

[0064] The method for manufacturing an electrode assembly according to one embodiment of the present invention may further include a step of removing the induction heating unit from the moving path of the electrode assembly before the heat press step. Thereby, a physical collision between the induction heating unit and the heat press unit can be prevented.

[0065] Also, a physical collision between the gripper and the heat press unit can be prevented even through the first heat press step and the second heat press step described later.

[0066] The method for manufacturing an electrode assembly according to one embodiment of the present invention may further include a standby step of allowing the laminate to stand in the atmosphere for a predetermined time between the induction heating step and the heat press step. The atmosphere state means that after the induction heating step, the induction heating is stopped for a predetermined time and waiting for the heat applied to the laminate by the induction heating to diffuse throughout the laminate.

[0067] The heat transferred to a partial region of the laminate through the standby stage can be transferred to the entire region of the laminate. Thus, by intentionally suspending (stopping the induction heating of the laminate for a predetermined time) the induction heating of the laminate for a predetermined time before performing the heat press stage, the heat transferred to the laminate by the induction heating is evenly diffused throughout the laminate.

[0068] Then, by heating and pressing the laminate through the subsequent heat press stage, the uniformity of the thickness of the electrodes can be enhanced over the entire electrode assembly.

[0069] In one embodiment of the present invention, the standby stage may be executed for 3 seconds or more and 60 seconds or less, preferably 5 seconds or more and 45 seconds or less, and more preferably 10 seconds or more and 40 seconds or less.

[0070] When the time range is satisfied, it is possible to ensure a time during which the heat transferred to a partial region of the electrodes inside the laminate by the induction heating can be evenly distributed throughout the laminate. That is, when the standby stage is executed for less than 3 seconds, the heat transferred to a partial region of the laminate is unlikely to be transferred to the entire electrodes. On the other hand, when the standby stage is executed for more than 60 seconds, there may be a problem that the temperature of the electrodes increased by the transferred heat may be cooled, resulting in a reduction in the effect of the induction heating.

[0071] The standby time can be changed according to the time during which the laminate is heated and the heating temperature range in the subsequent heat press stage.

[0072] In one embodiment of the present invention, the step of manufacturing a laminate in which first electrodes and second electrodes are alternately arranged between folded separation membranes can utilize techniques commonly used in the art. For example, a first electrode may be laminated on the stack table, and after the first electrode is covered with a separation membrane, a second electrode may be laminated on the upper surface of the separation membrane. Next, the separation membrane may be folded to cover the second electrode, and subsequently, the process of laminating a first electrode on the upper surface of the separation membrane may be repeated. This is referred to as the zigzag stacking method in this embodiment. At this time, in the process of the separation membrane moving while covering the first electrode or the second electrode placed on the separation membrane, methods such as the stack table moving left and right, the separation membrane moving left and right, and the stack table rotating may be applied.

[0073] In the zigzag stacking method, a holding mechanism can hold the laminate and maintain the alignment of the laminate during the process of laminating the first electrode, the second electrode, and the separation membrane.

[0074] As used herein, the "holding mechanism" is a component that holds the laminate placed on the stack table in the zigzag stacking method for laminating the first electrode or the second electrode, and is different from the gripper that holds the laminate in the heat press step.

[0075] In one embodiment of the present invention, the separation membrane can be supplied in the form of a separation membrane sheet. That is, the additionally supplied separation membrane may be supplied in a continuous form. Also, the "upper surface" may mean the opposite surface of the surface on which the separation membrane or the electrode is placed on the stack table.

[0076] The method for manufacturing an electrode assembly according to one embodiment of the present invention may include, as described above, a heat press step of heating and pressing the inductively heated laminate. The heat press step may be to heat while pressing the laminate in the direction of the lamination axis. Also, the heat press step may be performed by a heat press unit described later.

[0077] Further, in one embodiment of the present invention, the heat pressing step may include moving the laminate between a pair of pressing blocks including a press heater; the pair of pressing blocks moving relative to each other in the direction of the lamination axis to surface-press the laminate; and heating the laminate.

[0078] The pair of pressing blocks may be a lower plate and an upper plate facing the lower plate.

[0079] Further, in one embodiment of the present invention, the heat pressing step may include moving the laminate between a pair of pressing blocks; the pair of pressing blocks moving in the direction of the lamination axis to surface-press the laminate; and heating the laminate by a separately provided press heater.

[0080] That is, the press heater may be included in the pressing block or provided as a separate configuration.

[0081] The method for manufacturing an electrode assembly according to one embodiment of the present invention may further include releasing the grip of the gripper before the heat pressing step.

[0082] That is, the step of releasing the grip of the gripper may include stopping the surface pressing of the laminate by the gripper; and separating the gripper from the laminate.

[0083] Also, in the heat pressing step, the step of moving the laminate between a pair of pressing blocks including a press heater may include not only the case where only the laminate itself moves, but also the case where the laminate moves 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 pressing blocks and the press heater may mean the laminate and the stack table.

[0084] In one embodiment of the present invention, in the heat press step, the laminate may be heated and pressed for 5 seconds to 60 seconds under temperature conditions of 50°C to 90°C and pressure conditions of 0.5 Mpa to 6.0 Mpa. More preferably, the laminate may be heated and pressed for 5 seconds to 30 seconds under temperature conditions of 65°C to 90°C and pressure conditions of 1.0 Mpa to 6.0 Mpa. More preferably, the laminate may be heated and pressed for 7 seconds to 25 seconds under temperature conditions of 65°C to 85°C and pressure conditions of 3 Mpa to 5.5 Mpa.

[0085] When heating and pressing while satisfying the above conditions, the adhesion between the first electrode, the separation membrane, and the second electrode can be improved without damaging the first electrode, the separation membrane, and the second electrode. As a result, the performance of the electrode assembly can be improved.

[0086] In one embodiment of the present invention, the heat press step is not executed while the induction heating step is being executed.

[0087] In one embodiment of the present invention, the induction heating step may include: a step of measuring the temperature distribution on the surface of the laminate; a step of setting the induction heating temperature for the laminate according to the measured temperature distribution; and a step of induction heating the laminate based on the set induction heating temperature. That is, by adjusting the induction heating temperature of the laminate according to the temperature distribution on the upper surface of the laminate to be measured, the electrodes can be efficiently induction heated without using unnecessary energy.

[0088] In one embodiment of the present invention, the electrode tab induction heating step may be performed between the induction heating step and the heat press step. That is, the electrode tab induction heating step is executed after the induction heating step. This is because additional heating is required due to the rapid temperature change in the electrode tab portion even when the induction heating step is executed. This is to warm the laminate including the electrode tab to a uniform temperature in the heat press step, so the electrode tab induction heating step is executed before the heat press process.

[0089] That is, the method for manufacturing an electrode assembly according to an embodiment of the present invention may sequentially execute an induction heating step, an electrode tab induction heating step, and a heat pressing step. Further, a standby step may be additionally executed between the induction heating step and the electrode tab induction heating step.

[0090] <Electrode assembly manufacturing apparatus> An embodiment of the present invention provides an electrode assembly manufacturing apparatus including a first electrode, a separation membrane, and a second electrode.

[0091] For reference, a semi-finished state in which the first electrode, the separation membrane, and the second electrode are repeatedly laminated is represented by a laminate, and a separation membrane winding step is performed on the semi-finished product to distinguish one distinguishable component into an electrode assembly. Further, at least one of the first electrodes of the laminate may include a first electrode tab, and at least one of the second electrodes of the laminate may include a second electrode tab.

[0092] That is, the finally manufactured electrode assembly may also include at least one first electrode tab and at least one second electrode tab.

[0093] The electrode assembly manufacturing apparatus is characterized by including an induction heating unit and an electrode tab induction heating unit. The induction heating unit of the electrode assembly manufacturing apparatus of the present invention executes the induction heating step described above, and the electrode tab induction heating unit executes the electrode tab induction heating step described above. That is, when the electrode assembly manufacturing apparatus according to the present invention is used, in the process of executing the heat pressing step by the heat pressing unit, the laminate including the first electrode, the separation membrane, and the second electrode is uniformly heated, and a uniform adhesive force can be ensured between the layers in the laminate. As a result, it is possible to reduce the deviation of the separation membrane air permeability, the deviation of the separation membrane thickness change, and the deviation of the adhesive force due to the lamination position of the electrode assembly, and manufacture an electrode assembly having uniform performance while reducing the volume of the electrode assembly. Further, it is possible to manufacture an electrode assembly in which the energy density per unit volume increases.

[0094] The electrode assembly manufacturing apparatus according to the present invention may further include a separation membrane supply unit that supplies a separation membrane to a 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.

[0095] In one embodiment of the present invention, the induction heating unit may be a gripper that grips the laminate in order 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 inside the gripper or installed outside the gripper. When the gripper serves as the induction heating unit, it is possible to save the process space for installing the induction heating unit, and since induction heating can be performed while transferring, the process time can also be shortened. The gripper can perform the function of gripping the laminate while transferring the laminate from the stack table to the heat press unit.

[0096] 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, it may further include a gripper that grips and transfers the laminate between the stack table and the induction heating unit, and the induction heating unit may be one that performs induction heating while gripping the laminate with the gripper. Thereafter, the gripper may be transferred to the heat press unit while gripping the induction-heated laminate, whereby the laminate can be transferred without unnecessarily gripping or releasing the laminate at adjacent stages.

[0097] In one embodiment of the present invention, the induction heating unit may be separately installed from the gripper that transfers the laminate. That is, the induction heating unit may include a first induction heating device including an induction heating coil; and a first device moving unit that moves the first induction heating device to the surface of the laminate. When the first device moving unit moves the first induction heating device to an appropriate distance from the laminate, the first induction heating device can induction heat the laminate. When the induction heating of the laminate is completed, the first device moving unit can separate the first induction heating device from the laminate.

[0098] In this case, as described above, there is an advantage that it is easy to apply even when the thickness of the laminate is thick, and it can be utilized even when induction heating the electrode tab.

[0099] In this specification, "section" means an interface that executes a specific function within the electrode assembly manufacturing apparatus.

[0100] The induction heating coil of the electrode assembly manufacturing apparatus according to one embodiment of the present invention may be in contact with or separated from the laminate by a predetermined distance. At this time, the predetermined distance may be 15 mm or less. More specifically, it may be more than 0 mm and 15 mm or less, preferably 0.05 mm or more and 10 mm or less, and more preferably 0.3 mm or more and 5 mm or less.

[0101] The advantages when the induction heating coil is in contact with the laminate and the advantages when the induction heating coil is separated from the laminate by a predetermined distance are as described in the electrode assembly manufacturing method.

[0102] In one embodiment of the present invention, the induction heating unit may include an induction heating coil and an induction heating plate.

[0103] Further, the induction heating coil may be included inside an induction heating plate containing a non-conductive material. The induction heating plate may include an AC generator that provides an alternating current to the induction heating coil, and may perform a function of protecting the induction heating coil. Using a non-conductive material as the material of the induction heating plate is to prevent an induced current generated by the induction heating coil from also being generated in the induction heating plate.

[0104] The induction heating plate may be a mold made of a non-conductive material. The non-conductive material may be, but is not limited to, epoxy.

[0105] Also, the induction heating coil and the induction heating plate may form a set.

[0106] 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 can be applied.

[0107] The electrode assembly manufacturing apparatus according to an embodiment of the present invention may further include a first control unit that measures the temperature distribution on the surface of the laminate and sets the induction heating temperature for the laminate according to the measured temperature distribution, or determines whether to interrupt the induction heating of the laminate based on the induction heating temperature and the induction heating time for the laminate.

[0108] Also, the first control unit can also adjust the induction heating time for the laminate.

[0109] That is, the first control unit can set the conditions for performing the induction heating stage and the conditions for performing the standby stage. For each condition, the content described above in the electrode assembly manufacturing method can be applied.

[0110] In one embodiment of the present invention, the electrode tab induction heating unit may include a second induction heating device including an induction heating coil, and a second device moving unit configured to move the second induction heating device to a first electrode tab or a second electrode tab portion. When the second device moving unit moves the second induction heating device to an appropriate distance from the electrode tab, the second induction heating device can induction heat the electrode tab. When the induction heating of the electrode tab is completed, the second device moving unit can separate the second induction heating device from the electrode tab. This process may be executed via a second control unit that functions to control the operation of the electrode tab induction heating unit according to the conditions of the electrode tab induction heating stage described above.

[0111] In one embodiment of the present invention, the induction heating coil may be in contact with or spaced apart from at least one of the first electrode tab and the second electrode tab by a predetermined distance. At this time, the predetermined distance may be 15 mm or less. More specifically, it may be more than 0 mm and 15 mm or less, preferably 0.05 mm or more and 10 mm or less, and even more preferably 0.3 mm or more and 5 mm or less.

[0112] The advantages when the induction heating coil is in contact with the electrode tab and the advantages when the induction heating coil is spaced apart from the electrode tab by a predetermined distance are as described in the method for manufacturing the electrode assembly.

[0113] In one embodiment of the present invention, the electrode tab induction heating unit may include an induction heating coil and an induction heating plate. The descriptions of the induction heating coil and the induction heating plate of the electrode tab induction heating unit may be applicable to the induction heating coil and the induction heating plate of the induction heating unit. However, some forms and sizes may be different depending on the difference in the size and position of the heating target.

[0114] In one embodiment of the present invention, the heat press unit may be composed of a pair of pressing blocks, and the pair of pressing blocks may be moved in a direction facing each other to surface-press the laminate.

[0115] The heat press part 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 in a direction facing each other, so that the laminate placed between the pressure blocks can be surface-pressed.

[0116] At this time, the pair of pressure blocks may include a press heater inside thereof.

[0117] In another embodiment of the present invention, the heat press part may be two heat press parts that are separable. That is, it may include a first heat press part and a second heat press part.

[0118] Referring to FIG. 7, the first heat press part may include a pair of first pressure blocks. The pressure surfaces of the pair of first pressure blocks may include grooves in a form corresponding to the gripper so that the laminate can be pressed in a state where the gripper grips the laminate. The pressure surfaces other than the grooves may be flat surfaces. The second heat press part may include a pair of second pressure blocks. The pressure surfaces of the pair of second pressure blocks may be provided as flat surfaces. 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.

[0119] When the heat press part is divided into two parts as described above, it is possible to prevent the heated laminate from being cooled while being transferred, and the adhesive force between the layers inside the laminate from being lost.

[0120] The conditions for heating and pressing the laminate in the heat press part are the same as the conditions in the heat press stage described above.

[0121] The electrode assembly manufacturing apparatus according to an embodiment of the present invention may be such that the induction heating unit, the electrode tab induction heating unit, and the heat press unit operate sequentially. That is, as described above, the apparatus may operate so that the electrode tab induction heating step can be executed between the induction heating step and the heat press step.

[0122] 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.

[0123] The ratio of the total length to the total width of the electrode assembly may be 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.

[0124] An embodiment of the present invention includes a first press unit including induction heating and a second press unit for heating and pressing the induction-heated electrode assembly after the laminate is assembled on the stacking table to complete the electrode assembly. In particular, in the case of a large-sized electrode assembly such as the electrode assembly, when heated by a direct contact method, a temperature deviation may occur particularly between the position inside the electrode assembly, especially between the outermost contour of the electrode assembly and the central portion of the electrode assembly. However, when the embodiment of the present invention is applied to a large-sized electrode assembly, it can show an advantage of uniformly heating the whole regardless of the position inside the electrode assembly even if the thickness of the electrode assembly is thick.

[0125] In one embodiment of the present invention, the stack table may include a table body on which the laminate is placed and a drive unit for driving the table body. The table body may include a stack table heater capable of heating the laminate at a predetermined temperature when the laminate is placed.

[0126] In one embodiment of the present invention, the first electrode supply unit may include at least one of a first electrode mounting table, a first electrode roll, a first cutter, a first conveyor belt, and a first electrode supply head.

[0127] Further, the first electrode mounting table may include a first electrode heater that heats the first electrode placed on the first electrode mounting table to a predetermined temperature.

[0128] In one embodiment of the present invention, the second electrode supply unit may include at least one of a second electrode mounting table, a second electrode roll, a second cutter, a second conveyor belt, and a second electrode supply head.

[0129] Further, the second electrode mounting table may include a second electrode heater that heats the second electrode placed on the second electrode mounting table to a predetermined temperature.

[0130] In one embodiment of the present invention, the first electrode stacking unit includes a first vacuum head that vacuum-sucks the first electrode mounted on the first electrode mounting table. The first electrode can be moved from the first electrode mounting table to the stacking table by the first electrode stacking unit.

[0131] The second electrode stacking unit may include a second vacuum head that vacuum-sucks the second electrode mounted on the second electrode mounting table. The second electrode can be moved from the second electrode mounting table to the stacking table by the second electrode stacking unit.

[0132] In one embodiment of the present invention, the first electrode may be a positive electrode and the second electrode may be a negative electrode.

[0133] In one embodiment of the present invention, the first electrode may be a negative electrode and the second electrode may be a positive electrode.

[0134] In one embodiment of the present invention, if the current collectors, active materials, conductive materials, etc. used for the positive electrode and the negative electrode are those known in the art, they can be used without limitation, and the methods for manufacturing the positive electrode and the negative electrode can also be used without limitation those known in the art.

[0135] In one embodiment of the present invention, the separator can also be used without limitation as long as it is a separator known in the art, and the method for manufacturing the separator can also be used without limitation those known in the art. However, in one embodiment of the present invention, the separator includes 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 particulate binder resin and inorganic particles.

[0136] 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, hybrid polymer particles of acrylic polymer particles and acrylic polymers.

[0137] In one embodiment of the present invention, the fluorine-based polymer may be a homopolymer of vinylidene fluoride, a copolymer of vinylidene fluoride and other polymerizable monomers, or a mixture of two or more thereof.

[0138] In one embodiment of the present invention, the inorganic particles may be Al2O3, but are not limited thereto.

[0139] Since the organic / inorganic composite porous coating layer is included, it becomes possible to manufacture an electrode assembly with enhanced adhesive force between the electrodes and the separator by applying the induction heating step and the heat pressing step described in the electrode assembly manufacturing method and / or the electrode assembly manufacturing apparatus.

[0140] Hereinafter, the electrode assembly manufacturing apparatus and the electrode assembly manufacturing method according to an embodiment of the present invention will be described in more detail. Hereinafter, it will be described on the premise that the electrode assembly of the present invention is zigzag stacked.

[0141] FIG. 1 shows a cross-sectional view of the process flow of the electrode assembly manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing the process flow of the electrode assembly manufacturing apparatus according to an embodiment of the present invention in a planar manner. Here, for the sake of convenience, in FIG. 1, the holding mechanism 170, the heat press part 180, and the induction heating part 190 shown in FIG. 2 are omitted, and in FIG. 2, the separation membrane supply part 120 shown in FIG. 1 is omitted.

[0142] Referring to FIGS. 1 to 3, the electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention includes a separation membrane supply part 120 that supplies the separation membrane 14 to the stack table 110, a first electrode supply part 130 that supplies the first electrode 11 to the stack table 110, and a second electrode supply part 140 that supplies the second electrode 12 to the stack table 110. At this time, the separation membrane 14, the first electrode 11, and the second electrode 12 can also be supplied to the stack table 110 while being heated by the first electrode supply part 130 and the second electrode supply part 140, respectively.

[0143] Further, the electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention includes a first electrode stack part 150 that stacks the first electrode 11 supplied by the first electrode supply part 130 on the stack table 110, and a second electrode stack part 160 that stacks the second electrode 12 supplied by the second electrode supply part 140 on the stack table 110. At this time, the separation membrane 14 supplied by the separation membrane supply part 120 is stacked in a zigzag shape while alternately reciprocating between the left side and the right side of the stacking axis with respect to the stacking axis. At this time, either one of the first electrode 11 and the second electrode 12 is alternately inserted into the space (between the separation membranes) generated while the separation membrane 14 is being folded, and as a result, a laminate in which the first electrode 11, the separation membrane 14, the second electrode 12, and the separation membrane 14 are repeatedly stacked is placed on the stack table 110.

[0144] 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 selectively applicable.

[0145] 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.

[0146] Also, the second electrode supply unit 140 may 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.

[0147] The first electrode stacking unit 150 stacks the first electrode 11 on the stacking table 110. At this time, the first electrode stacking unit 150 may include a first vacuum head 151, a first head heater (not shown), and a first moving unit 153. Also, the second electrode stacking unit 160 stacks the second electrode 12 on the stacking table 110. The second electrode stacking unit 160 may include a second vacuum head 161, a second head heater (not shown), and a second moving unit 163.

[0148] The first electrode stacking unit 150 and the second electrode stacking unit 160 may further include a heater (not shown) for preheating the first electrode and the second electrode in some cases.

[0149] Further, 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 heats and presses the stack placed on the stack table 110 to bond between the first electrode 11, the separation membrane 14, and the second electrode 12.

[0150] Moreover, the electrode assembly manufacturing apparatus 100 according to an embodiment of the present invention further includes an induction heating unit 190 that induction-heats the stack to transfer heat to the electrodes within the stack. Further, it may further include a control unit (not shown) that controls the operation availability of the induction heating unit 190 and the like. Thereby, finally, the electrode assembly 10 as shown in FIG. 3 can be manufactured.

[0151] FIG. 3 is a cross-sectional view exemplarily showing an electrode assembly manufacturing apparatus according to an embodiment of the present invention and an electrode assembly manufactured through the electrode assembly manufacturing method.

[0152] Referring to FIG. 3, the electrode assembly 10 may be in a form in which the separation membrane 14 folded in a zigzag manner and stacked, and the first electrode 11 or the second electrode 12 inserted into the space between the separation membranes 14 are alternately inserted and stacked.

[0153] At this time, the electrode assembly 10 may be provided in a form in which the separation membrane 14 surrounds the outermost contour of the stack. However, the configuration of the electrode assembly 10 is not limited to the example shown in FIG. 3.

[0154] FIGS. 4 and 5 are diagrams schematically showing the operation process of the induction heating unit according to the present invention.

[0155] Specifically, FIG. 4 shows the case where the induction heating unit 190 is the 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 performing induction heating with the gripper 51, the laminate S can be transferred to the heat press unit 180. In the heat press unit 180, the laminate S can be heated and pressed. At this time, before heating and pressing the laminate S in the heat press unit 180, a standby process (stage) of stopping the induction heating on the laminate S and waiting for a predetermined time may be executed. At this time, the conditions of the standby process can be set by a control unit (not shown).

[0156] FIG. 5 shows, as another embodiment of induction heating, induction heating of the laminate S using an induction heating unit 190 provided separately from the gripper 51. At this time, the laminate S is induction heated after being moved to the induction heating device. When the induction heating is completed, similar to FIG. 4, the laminate S can be heated and pressed in the heat press unit 180. At this time, before heating and pressing the laminate S in the heat press unit 180, a standby process (stage) of stopping the induction heating on the induction-heated laminate S and waiting for a predetermined time may be executed. Also in this case, the conditions of the standby process can be adjusted by a control unit (not shown). As shown in FIG. 5, the standby process may be performed in a state where the laminate S is gripped by the gripper 51 after being separated from the induction heating unit 190.

[0157] FIG. 6 is a diagram schematically showing the operation process of the electrode tab induction heating unit according to the present invention. FIG. 6 shows, as an example, a case where the laminate S is induction heated using an induction heating unit 190 provided separately from the gripper 51. As described with reference to FIG. 5, an induction heating step, a standby step, and a heat press step may be executed on the laminate S. At this time, the portion of the first electrode tab 10a can be induction heated by the electrode tab induction heating unit 193 between the standby step and the heat press step. Thereby, the temperature of the electrode tab portion, which has relatively significantly decreased in temperature, can be raised, and the laminate S can be pressed at a uniform temperature in the heat press step. At this time, a plurality of the first electrode tabs may be included in the laminate. Further, the laminate S may include a second electrode tab (not shown), and the execution of induction heating on the second electrode tab may be applied in the same manner as the induction heating on the first electrode tab. A plurality of the second electrode tabs may also be included in the laminate. The conditions for each step may be applied to the above-described content.

[0158] FIG. 7 exemplarily shows an induction heating unit according to an embodiment of the present invention. Referring to FIG. 7, the 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 can be incorporated inside induction heating plates 192a and 192b. The induction heating coil 191 may have a U shape. The induction heating coils 191a and 191b may be in a form facing each other, and the specific arrangement of the induction heating coil 191 may be arranged as shown in FIG. 7, but is not limited thereto.

[0159] When an alternating current is applied to the induction heating coil 191, an induced current can be generated in the metallic electrode in the electrode assembly, and thus the electrode is heated by the induced current. Therefore, it is also possible to generate induction heating targeting the electrode disposed in a specific layer in the electrode assembly.

[0160] The present invention is characterized in that, in a heat press step of heating and pressurizing an electrode assembly, induction heating is performed in advance before the heat press step, targeting an electrode disposed particularly at the center of the electrode assembly where heating is vulnerable.

[0161] FIG. 8 shows the configuration of the heat press section. In particular, the case where the heat press section includes a first heat press section 50 and a second heat press section 60 is shown.

[0162] FIG. 8(a) is a perspective view showing the first heat press section 50, and FIG. 8(b) is a perspective view showing the second heat press section 60.

[0163] Referring to FIG. 8(a), the first heat press section 50 can heat and pressurize the laminate S while being fixed by the gripper 51. The first heat press section 50 can be composed of a pair of first pressure blocks 50a and 50b. The pair of first pressure blocks 50a and 50b are provided with flat pressure surfaces in all parts except for grooves in a form corresponding to the fixing part 51b of the gripper 51.

[0164] The gripper 51 may include a main body 51a corresponding to or wider than the length x and height y of the laminate S, and a fixing part 51b protruding from the main body 51a to fix the laminate S. Here, the length x of the laminate S means the portion with the longest distance from one end to the other end of the laminate S, the height y means the distance in the laminating direction of the laminate S, and the width z may mean the distance across the upper surface of the laminate S horizontally.

[0165] The fixing part 51b is position-adjustable along the height direction of the main body 51a, and the fixing part 51b can contact the upper and lower surfaces of the laminate S to fix the laminate S.

[0166] Thereafter, the pair of first pressure blocks 50a and 50b move in a mutually facing direction to heat and pressurize the laminate S. By the heating and pressurization, the electrodes and the separation film inside the electrode assembly are stably joined.

[0167] The first heat press section 50 may be a component that compensates for cooling during the movement of the induction-heated electrode assembly, or may be selectively provided. That is, it may be omitted depending on the case.

[0168] Referring to FIG. 8(b), the second heat press section 60 can finally heat and press the laminate S that has been primarily heated and pressed by the first heat press section 50. The second heat press section 60 includes a pair of second pressure blocks 60a and 60b, and the pair of second pressure blocks 60a and 60b can be moved in a direction facing each other to perform surface pressure on the laminate S. Further, all of the pressure surfaces of the pair of second pressure blocks 60a and 60b included in the second heat press section 60 that come into contact with the laminate S and apply pressure may be provided as flat surfaces.

[0169] The description regarding 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. The reverse is also true.

[0170] <Electrode assembly> In this specification, the "outermost contour of the electrode assembly" means the uppermost position or the lowermost position in the stacking direction of the laminate.

[0171] Also, in this specification, the "middle of the electrode assembly" means a position corresponding to the middle portion between the uppermost position and the lowermost position in the stacking direction of the laminate stacked with reference to the stacking axis.

[0172] One embodiment of the present invention provides an electrode assembly including a first electrode, a separator, and a second electrode manufactured by the method for manufacturing an electrode assembly and / or the apparatus for manufacturing an electrode assembly according to the present invention. That is, the electrode assembly may be an electrode assembly stacked by the Zig Zag Stacking method.

[0173] However, the electrode assembly can be in the form of a laminate and folding (L&F) structure in which the electrodes and the separator membrane are wound, or in a stacking and laminating (S&L) structure in which the electrodes and the separator membrane are sequentially laminated. That is, in the present invention, after the electrode assembly is completed, in order to improve the adhesive force between the electrodes and the separator membrane in the electrode assembly, a step of heating and pressing the electrode assembly is added, so that it is applicable to various forms of electrode assemblies.

[0174] In one embodiment of the present invention, since the electrode assembly is compressed while being heated, the energy density per unit volume can be increased. That is, since the electrode assembly is pressurized while being heated as compared with the case of simply laminating the electrodes and the separator membrane and then packaging, the volume of the electrode assembly decreases.

[0175] In particular, the reduction in the volume of the electrode assembly can be realized through the separator membrane. In this specification, the fact that the separator membrane is compressed after zigzag stacking means that the separator membrane of the electrode assembly is compressed as compared with the separator membrane before compression.

[0176] That is, in one embodiment of the present invention, the compression ratio of the separator membrane located at the outermost periphery of the electrode assembly is larger than the compression ratio of the separator membrane located in the middle of the electrode assembly, and the difference in the compression ratio may be 3%p (Percentage Point) or less, preferably 2%p or less, more preferably 1.5%p or less.

[0177] In one embodiment of the present invention, the compression ratio of the separator membrane located at the outermost periphery of the electrode assembly may be 3% - 8%, preferably 4% - 8%.

[0178] In one embodiment of the present invention, the compression ratio of the separator membrane located in the middle of the electrode assembly may be 3% - 8%, preferably 4% - 8%.

[0179] In one embodiment of the present invention, the compression ratio of the separation membrane located at the outermost contour of the electrode assembly is 3% to 8%, preferably 4% to 8%, and the compression ratio of the separation membrane located in the middle of the electrode assembly may be 3% to 8%, preferably 4% to 8%.

[0180] The compression ratio of the separation membrane can be calculated through the difference between the thickness of the supplied separation membrane (original thickness before the process) and the thickness of the separation membrane after the completion of the electrode assembly (after the process).

[0181] In one embodiment of the present invention, the thickness of the separation membrane located in the middle of the electrode assembly is 1 times or more and 1.09 times or less, preferably more than 1 time and 1.09 times or less, more preferably more than 1 time and 1.05 times or less, still more preferably more than 1 time and 1.03 times or less of the thickness of the separation membrane located at the outermost contour of the electrode assembly.

[0182] That is, in one embodiment of the present invention, the thickness of the separation membrane located at the outermost contour of the electrode assembly is thinner than the thickness of the separation membrane located in the middle of the electrode assembly, and the thickness of the separation membrane located in the middle of the electrode assembly may be 1.09 times or less of the thickness of the separation membrane located at the outermost contour of the electrode assembly.

[0183] In one embodiment of the present invention, the deviation of the thickness of the separation membrane of the electrode assembly may be 9% or less, preferably 5% or less, more preferably 3% or less.

[0184] The electrode assembly according to the present invention is manufactured by heating and pressing a laminate (unfinished electrode assembly) in which electrodes and a separation membrane are laminated. Since the thickness deviation between the outermost separation membrane of the electrode assembly and the middle separation membrane of the electrode assembly is the largest, by comparing the thicknesses of the outermost separation membrane and the middle separation membrane of the electrode assembly, it is possible to confirm whether the deviation of the thickness of the separation membrane of the electrode assembly is within the numerical range.

[0185] One embodiment of the present invention is an electrode assembly including a first electrode, a separation membrane, and a second electrode, wherein the electrode assembly is Zig Zag Stacking, and after the Zig Zag Stacking, the electrode assembly is heated and pressurized to provide an electrode assembly satisfying the following formula 1. [Formula 1] 1.02E A ≦E B In the above formula 1, E A is the energy density Wh / L of the electrode assembly before heating and pressurization, E B is the energy density Wh / L of the electrode assembly after heating and pressurization.

[0186] In one embodiment of the present invention, the electrode assembly can satisfy the formula 1. Specifically, the formula 1 is 1.02E A ≦E B , preferably, 1.03E A ≦E B may be. That is, the energy density (Wh / L) increases due to the compression of the separation membrane and the electrodes during the heating and pressurization process. At this time, the energy density means the power per unit volume.

[0187] The energy density is a value calculated by decomposing the electrode assembly, obtaining the energy density at the outermost and intermediate positions of the electrode assembly, and then averaging the values.

[0188] Thus, the electrode assembly according to the embodiment of the present application has the effect that the performance is uniform and the breakdown voltage is more excellent because the thickness of the separation membrane is uniform.

[0189] In one embodiment of the present invention, the compression ratio of the separation membrane located at the outermost of the electrode assembly may be larger than the compression ratio of the separation membrane located in the middle of the electrode assembly.

[0190] That is, since the thickness of the separation membrane in the electrode assembly according to the present invention is uniform, the performance is uniform and the withstand voltage is more excellent.

[0191] In one embodiment of the present invention, the withstand voltage of the electrode assembly may be 1.5 kV or more.

[0192] In addition, the description regarding 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.

[0193] In one embodiment of the present invention, the air permeability of the separation membrane 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, more preferably 85 sec / 100 ml to 100 sec / 100 ml.

[0194] In addition, in one embodiment of the present invention, the air permeability of the separation membrane located on the outermost periphery 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, more preferably 85 sec / 100 ml to 100 sec / 100 ml.

[0195] According to one embodiment of the present invention, the deviation between the air permeability of the separation membrane located in the middle of the electrode assembly and the air permeability of the separation membrane located on the outermost periphery 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.

Examples

[0196] As described above in detail for the embodiments of the present invention, the scope of the rights of the present invention is not limited thereto, and it is obvious to those having ordinary knowledge in the technical field that various modifications and variations are possible without departing from the technical idea of the present invention described in the claims.

[0197] <Manufacture of Electrode Assembly>

[0198] 1) Example 1 19 positive electrodes, 20 negative electrodes, and a separator were supplied from a positive electrode supply unit, a negative electrode supply unit, and a separator supply unit, respectively, to a stack table.

[0199] More specifically, the positive electrode and the negative electrode were supplied in a form cut by a positive electrode sheet and a negative electrode sheet, respectively, and the separator was supplied in the form of a separator sheet. At this time, the positive electrode and the negative electrode were manufactured to have a positive electrode tab and a negative electrode tab, respectively. Then, while rotating the stack table, the supplied separator was folded, and the positive electrode, the negative electrode, and the separator were laminated.

[0200] At this time, the positive electrode and the negative electrode were supplied using an electrode stack unit including a vacuum head, an electrode non-contact heater, and a moving unit, respectively.

[0201] At the same time, the stacking of the positive electrode or the negative electrode laminated on the uppermost side of the stack table was performed by a holding mechanism. As a result, a laminate (electrode assembly) in which the positive electrode, the negative electrode, and the separator were zigzag stacked was manufactured.

[0202] Next, the laminate was induction heated for 15 seconds (induction heating step) in an induction heating unit including a U-shaped induction heating coil. Then, after waiting for 15 seconds (waiting step), it was executed. After the waiting step, the electrode tab of the laminate was induction heated for 15 seconds (electrode tab induction heating step) in an electrode tab induction heating unit including a U-shaped induction heating coil. Next, the laminate was heated and pressurized for 15 seconds (heat press step) under a temperature condition of 70°C and a pressure condition of 3.5 MPa to manufacture the electrode assembly of Example 1.

[0203] During the manufacturing process, the surface temperature change of the laminate S was measured. Specifically, the heated portion of the surface of the laminate S that is heated by the U-shaped induction heating coil and the unheated portion that is not heated by the U-shaped induction heating coil were distinguished, and the temperature change was measured for each portion. The results are as shown in FIG. 9.

[0204] The content described above regarding the present invention can be applied during the process of manufacturing the electrode assembly.

[0205] Next, using an adhesion measuring instrument, the adhesion pattern of the electrode assembly of Example 1 was measured, and the results are as shown in FIG. 10. Specifically, the adhesion pattern of the electrode assembly was measured in the direction of the arrow in FIG. 10.

[0206] From the results in FIG. 9, it was confirmed that when the induction heating process is executed, the temperature of the surface of the laminate can be increased. In particular, since induction heating is possible for the electrodes that are not located on the outermost contour of the laminate that do not come into direct contact, it was confirmed that temperature non-uniformity between the electrodes in the heat press process can be prevented.

[0207] Also, from the results in FIG. 9, it was confirmed that when the standby process is executed, the temperature deviation between the heated portion and the unheated portion can also be reduced. Since the temperature deviation decreased, as shown in FIG. 10, it was confirmed that the adhesion pattern of the electrode assembly is uniform.

[0208] Additionally, by induction heating the electrode tab portion, it was confirmed that the electrode tab portion is also adhered uniformly.

[0209] 2) Comparative Example 1 The electrode assembly of Comparative Example 1 was manufactured in the same manner as in Example 1, except that induction heating, electrode tab induction heating, and the standby process were not performed in Example 1.

[0210] <Experimental Example 1 - Evaluation of the Change in the Original Thickness of the Separation Membrane and the Compression Ratio of the Separation Membrane> For the electrode assemblies of Example 1 and Comparative Example 1, the change in the original thickness of the separation membrane and the compression ratio of the separation membrane were evaluated.

[0211] Specifically, after measuring the original thickness of the separation membrane before lamination, the electrode assemblies of Example 1 and Comparative Example 1 were disassembled, and based on the lamination direction of the electrode assembly, the separation membrane located at the upper end (outermost contour) of the electrode assembly and the separation membrane corresponding to the middle position (central part) between the upper and lower ends of the electrode assembly were collected, the change in the original thickness of the separation membrane before and after the process was measured, and the results are shown in Table 1 below. Also, the compression rate of the separation membrane was calculated from the change value of the original thickness of the separation membrane and shown in Table 1 below.

[0212]

Table 1

[0213] As can be confirmed from Table 1 above, when the induction heating and standby processes are not performed, it can be confirmed that the deviation in the change of the original thickness of the separation membrane is large. In the case of the outermost contour, it can be confirmed that the original thickness of the separation membrane decreases more than necessary, and in the case of the central part, it can be confirmed that almost no change in the original thickness of the separation membrane occurs. That is, in the case of Comparative Example 1, it was confirmed that, unlike Example 1, a large deviation in the separation membrane thickness occurs depending on the position of the electrode assembly.

[0214] This means that it is difficult for the electrode assembly to have uniform performance regardless of its position. That is, it was confirmed that the electrode assembly manufactured by the manufacturing apparatus and method according to the present invention has uniform performance.

[0215] <Experimental Example 2 - Dielectric Voltage Withstand Evaluation> The dielectric voltage withstand of the electrode assemblies of Example 1 and Comparative Example 1 was evaluated. The results are shown in Table 2 below.

[0216]

Table 2

[0217] <Experimental Example 3 - Evaluation of Air Permeability of Separation Membrane> The electrode assemblies of Example 1 and Comparative Example 1 were disassembled, and the separation membrane corresponding to the intermediate position between the upper end and the lower end of the electrode assembly was collected based on the stacking direction of the electrode assembly, and then cut to prepare a separation membrane sample with a size of 5 cm × 5 cm (width × length). Then, the separation membrane sample was washed with an organic solvent. Thereafter, in accordance with the Japanese Industrial Standard Gurley (JIS Gurley) measurement method, using a Toyoseiki Gurley type Densometer (No. 158), the time required for 100 ml (or 100 cc) of air to pass through a one - square - inch separation membrane under normal temperature and a pressure condition of 0.05 MPa was measured to determine the air permeability of Example 1 and Comparative Example 1.

[0218] The results are shown in Table 3 below.

[0219]

Table 3

[0220] As can be confirmed from Table 3 above, it was confirmed that Example 1 and Comparative Example 1 had similar air permeabilities.

[0221] From the above experimental examples, it was confirmed that the electrode assembly device of the present invention and the electrode assembly manufactured by the method had excellent stability of the electrodes and the separation membrane and had an appropriate level of air permeability without deformation of the separation membrane.

[0222] Also, it was confirmed that an electrode assembly with excellent breakdown voltage and uniform performance could be manufactured.

Explanation of Reference Signs

[0223] 10 ··· Electrode assembly body 10a ··· First electrode tab 11 ··· First electrode 12 ··· Second electrode 14 ··· Separation membrane 50 ··· First heat press part 50a, 50b ··· Pair of first pressure blocks 51 ··· Gripper 51a ··· Body 51b ··· Fixed part 60 ··· Second heat press part 60a, 60b ··· Pair of second pressure blocks 100 ··· Electrode assembly manufacturing device 110 ··· Stack table 111 ··· Table body 112 ··· Stack table heater 120 ··· Separation membrane supply part 121 ··· Separation membrane heating part 122 ··· Separation membrane roll 130 ··· First electrode supply part 131 ··· First electrode mounting table 133 ··· First electrode roll 134 ··· First cutter 135 ··· First conveyor belt 136 ··· First electrode supply head 140 ··· Second electrode supply part 141 ··· Second electrode mounting table 143 ··· Second electrode roll 144 ··· Second cutter 145 ··· Second conveyor belt 146 ··· Second electrode supply head 150 ··· First electrode stacking part 151 ··· First vacuum head 153 ··· First moving part 160 ··· Second electrode stacking part 161 ··· Second vacuum head 163 ··· Second moving part 170 ··· Holding mechanism 171 ··· First holding mechanism 172 ··· Second holding mechanism 180 ··· Heat press part 181 ··· First pressure block 182 ··· Second pressure block 190 ··· Induction heating part 191(191a, 191b) ··· Induction heating coil 192(192a, 192b) ··· Induction heating plate 193 ··· Electrode tab induction heating part S ··· Stacked product

Claims

1. A method for manufacturing an electrode assembly including a first electrode, a separation membrane, and a second electrode, comprising: a stacking step of stacking a laminate including the first electrode, the separation membrane, and the second electrode on a stack table; an induction heating step of induction heating the laminate; and a heat press step of heating and pressing the induction-heated laminate; wherein at least one of the first electrodes of the laminate includes a first electrode tab, at least one of the second electrodes of the laminate includes a second electrode tab, the method further includes an electrode tab induction heating step of induction heating at least one of the first electrode tab and the second electrode tab between the induction heating step and the heat press step.

2. The method for manufacturing an electrode assembly according to claim 1, wherein the electrode tab induction heating step is to induction heat at least one of the first electrode tab and the second electrode tab using an induction heating coil.

3. The method for manufacturing an electrode assembly according to claim 2, wherein the induction heating coil is in contact with or separated from at least one of the first electrode tab and the second electrode tab by a predetermined distance.

4. The method for manufacturing an electrode assembly according to claim 3, wherein the predetermined distance is 15 mm or less.

5. The method for manufacturing an electrode assembly according to claim 1, wherein the electrode tab induction heating step is performed for 1 second to 60 seconds.

6. The method for manufacturing an electrode assembly according to claim 1, wherein the induction heating step is to induction heat the laminate using an induction heating coil.

7. The induction heating step 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 press step, wherein in the transfer step, the laminate is induction heated by the gripper. The method for manufacturing an electrode assembly according to claim 1.

8. The induction heating step 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 press step, wherein the induction heating step is performed by the induction heating device. The method for manufacturing an electrode assembly according to claim 1.

9. The transfer step of transferring the laminate to the induction heating device including an induction heating coil is a step of gripping the laminate with a gripper and transferring it to the induction heating device. The method for manufacturing an electrode assembly according to claim 8, wherein the induction heating step is to perform induction heating while gripping the laminate with the gripper.

10. The method for manufacturing an electrode assembly according to claim 1, further comprising a standby step of allowing the laminate to stand in the atmosphere for a predetermined time between the induction heating step and the heat press step.

11. The method for manufacturing an electrode assembly according to claim 10, wherein the standby step is performed for 3 seconds or more and 60 seconds or less.

12. An electrode assembly manufacturing apparatus for manufacturing an electrode assembly including a first electrode, a separation film, and a second electrode, a stack table on which the first electrode, the separation film, and the second electrode are laminated and a laminate including the first electrode, the separation film, and the second electrode is placed; and a heat press unit that heats and presses the laminate; comprising at least one of the first electrodes of the laminate includes a first electrode tab, at least one of the second electrodes of the laminate includes a second electrode tab, an induction heating unit that induction heats the laminate while transferring the laminate from the stack table to the heat press unit; and an electrode tab induction heating unit that induction heats at least one of the first electrode tab and the second electrode tab before heating and pressing the laminate induction heated by the induction heating unit with the heat press unit; The electrode assembly manufacturing apparatus further comprising.

13. The electrode assembly manufacturing apparatus according to claim 12, 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.

14. The induction heating unit includes a first induction heating device including an induction heating coil; and a first device moving unit that moves the first induction heating device to the surface of the laminate; The electrode assembly manufacturing apparatus according to claim 12, comprising.

15. The apparatus further includes a gripper that grips and transfers the laminate between the stack table and the induction heating unit, The electrode assembly manufacturing apparatus according to claim 12, wherein the induction heating unit performs induction heating while gripping the laminate with the gripper.

16. measures the temperature distribution on the surface of the laminate and sets the induction heating temperature for the laminate according to the measured temperature distribution, or The electrode assembly manufacturing apparatus according to claim 12, further comprising a first control unit that determines whether to interrupt the induction heating of the laminate based on the induction heating temperature and the induction heating time for the laminate.

17. The electrode tab induction heating unit includes: a second induction heating device including an induction heating coil; and a second device moving unit that moves the second induction heating device to the first electrode tab or the second electrode tab portion. The electrode assembly manufacturing apparatus according to claim 12, comprising the above.

18. The electrode assembly manufacturing apparatus according to claim 17, wherein the induction heating coil is in contact with or separated from at least one of the first electrode tab and the second electrode tab by a predetermined distance.

19. The electrode assembly manufacturing apparatus according to claim 18, wherein the predetermined distance is 15 mm or less.

20. An electrode assembly including a first electrode, a separation membrane, and a second electrode, wherein the electrode assembly is zigzag stacked, the separation membrane is compressed after the zigzag stacking, the compression ratio of the separation membrane located at the outermost periphery of the electrode assembly is greater than the compression ratio of the separation membrane located in the middle of the electrode assembly, and the difference in the compression ratio is 3%p or less. The electrode assembly.

21. The electrode assembly according to claim 20, wherein the overall length of the electrode assembly is 400 mm to 600 mm and the overall width is 50 mm to 150 mm.

22. The electrode assembly according to claim 20, wherein the air permeability of the separation membrane located in the middle of the electrode assembly is 80 sec / 100 ml to 120 sec / 100 ml.

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