Electrode assembly, method for manufacturing same, and device for manufacturing same

Abstract

The present invention relates to a method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, the method comprising: a stacking step of stacking a stack including the first electrode, the separator, and the second electrode on a stacking table; an induction heating step of inductively heating the stack; and a heating and pressing step of heating and pressing the induction-heated stack, in which at least one of the first electrodes in the stack includes a first electrode tab and at least one of the second electrodes in the stack includes a second electrode tab, the method is further characterized by further comprising an electrode tab induction heating step of inductively heating at least one of the first electrode tab and the second electrode tab between the induction heating step and the heating and pressing step.

Description

Technical Field

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0000716 filed in the Korean Intellectual Property Office on January 3, 2023, Korean Patent Application No. 10-2023-0056378 filed in the Korean Intellectual Property Office on April 28, 2023, and Korean Patent Application No. 10-2024-0000188 filed in the Korean Intellectual Property Office on January 2, 2024, the entire contents of which are incorporated herein by reference.

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

[0003] Unlike primary batteries, secondary batteries can be recharged and can be formed into small sizes or large capacities. Therefore, a lot of research and development on secondary batteries is currently underway. With the development of technology and the increase in demand for mobile devices, the demand for secondary batteries as energy sources has increased dramatically.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, square batteries, and pouch-type batteries according to the shape of the battery case. In the secondary battery, an electrode assembly installed inside the battery case is a chargeable and dischargeable power generating device having a structure in which electrodes and separators are stacked.

[0005] Electrode assemblies can be roughly divided into: cake roll type electrode assemblies, in which a separator is inserted between the positive electrode and the negative electrode, each of the positive electrode and the negative electrode is provided in the form of a sheet coated with an active material, and then the positive electrode, the separator and the negative electrode are wound; stacked type electrode assemblies, in which a plurality of positive electrodes and negative electrodes with separators therebetween are stacked in sequence; and stacked folding type electrode assemblies, in which stacked unit cells are wound using a separator membrane with a longer length.

[0006] Here, in the stack folding type electrode assembly, the separator is folded and stacked in a zigzag form, and the positive electrode or the negative electrode is inserted between the folds of the separator. As a result, an electrode assembly in which the positive electrode, the separator, and the negative electrode are stacked is manufactured.

[0007] In this process, in order to bond the electrodes and the separator to each other, heat and pressure are applied to a stack in which the positive electrode, the separator, and the negative electrode are stacked.

[0008] However, it takes a long time and a lot of energy to combine the electrodes (positive electrode, negative electrode) in a stack with the separator by applying heat and pressure to the stack.

[0009] In addition, when applying heat and pressure to the stack, there is a problem that heat and pressure cannot be applied uniformly regardless of the stacking positions of the electrodes and the separators due to the difference in the stacking positions (stack heights) of the electrodes and the separators in the stack. That is, there is a problem that the adhesive force between the separator and the electrode is not constant.

[0010] Therefore, there is a problem of uneven performance of the electrode assembly.

[0011] [Citation List]

[0012] [Patent Document]

[0013] Korean Patent Application Publication No.10-2013-0132230 Summary of the invention

[0014] Technical issues

[0015] The present invention has been made in an effort to provide an electrode assembly, a manufacturing method thereof, and a manufacturing apparatus thereof for solving the problems caused by the non-constant adhesive force.

[0016] Technical Solution

[0017] An exemplary embodiment of the present invention provides a method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode, the method comprising: stacking a stack including the first electrode, the separator, and the second electrode on a stacking table; inductively heating the stack; and heating and pressing the inductively heated stack, wherein at least one of the first electrodes of the stack includes a first electrode connector, wherein at least one of the second electrodes of the stack includes a second electrode connector, and wherein the method further comprises performing inductive heating of the electrode connector by inductively heating at least one of the first electrode connector and the second electrode connector between the inductive heating and the heating and pressing.

[0018] Another exemplary embodiment of the present invention provides an electrode assembly manufacturing device for manufacturing an electrode assembly including a first electrode, a separator and a second electrode, the electrode assembly manufacturing device including: a stacking table on which the first electrode, the separator and the second electrode are stacked, and thus a stack including the first electrode, the separator and the second electrode is placed; and a heating and pressing unit, the heating and pressing unit being configured to heat and press the stack, wherein at least one of the first electrodes of the stack includes a first electrode connector, and at least one of the second electrodes of the stack includes a second electrode connector, and wherein the electrode assembly manufacturing device also includes an induction heating unit and an electrode connector induction heating unit, the induction heating unit being configured to inductively heat the stack while transferring the stack from the stacking table to the heating and pressing unit, the electrode connector induction heating unit being configured to inductively heat at least one of the first electrode connector and the second electrode connector before heating and pressing the stack that has been inductively heated in the induction heating unit in the heating and pressing unit.

[0019] Another exemplary embodiment of the present invention provides an electrode assembly comprising a first electrode, a separator, and a second electrode, wherein the electrode assembly is stacked in a zigzag form, wherein the separator is compressed after the zigzag stacking, and wherein a compression rate of a separator located at the outermost side of the electrode assembly is greater than a compression rate of a separator located in the middle of the electrode assembly, and the difference in compression rate is less than 3%p.

[0020] Technical Effects

[0021] An electrode assembly manufacturing method and an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present application may shorten the time required to manufacture an electrode assembly.

[0022] Since the electrode assembly manufacturing method and the electrode assembly manufacturing apparatus according to the exemplary embodiment of the present application can easily adjust the temperature of the electrode to a specific temperature range to reduce the temperature deviation between the electrodes, an electrode assembly having uniform performance can be provided.

[0023] The electrode assembly according to the exemplary embodiment of the present application has less deviation in air permeability of the separator according to the location and thus has an advantage of uniform performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a plan view illustratively showing an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0025] Figure 2 is a front view illustrating the concept of an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0026] Figure 3is a cross-sectional view illustratively showing a general electrode assembly.

[0027] Figure 4 and Figure 5 is a view illustratively showing a process of applying an electrode assembly manufacturing apparatus or a manufacturing method according to an exemplary embodiment of the present invention.

[0028] Figure 6 FIG. 1 is a view schematically showing an operation process of the electrode joint induction heating unit of the present invention.

[0029] Figure 7 is a view schematically illustrating an induction heating unit according to an exemplary embodiment of the present invention.

[0030] Figure 8 (a) is a perspective view showing a first heating and pressing unit 50 according to an exemplary embodiment of the present invention, and Figure 8 (b) is a perspective view illustrating the second heating and pressing unit 60 according to an exemplary embodiment of the present invention.

[0031] Fig. 9 is a graph showing a result of measuring a surface temperature variation of a stack during a process of manufacturing an electrode assembly according to an exemplary embodiment of the present invention.

[0032] Fig.10 is a diagram illustrating an adhesive force pattern of an electrode assembly according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0033] Hereinafter, exemplary embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the configurations described herein.

[0034] When a component “includes,” “contains,” or “has” a constituent element in the present specification, this does not mean to exclude another constituent element but means that another constituent element may be further included unless specifically described otherwise.

[0035] In an exemplary embodiment of the present invention, the electrode assembly may be stacked in a form in which the first electrodes and the second electrodes are alternately arranged between the folds of the folded separator.

[0036] In this specification, a stacking form in which the first electrodes and the second electrodes are alternately arranged between the folds of the folded separator is referred to as a zigzag stack.

[0037] In this case, a form in which the first electrodes and the second electrodes are alternately arranged between the folds of the folded separator is described more specifically, and the folded separator may mean separators stacked while overlapping in a zigzag form.

[0038] More specifically, the diaphragm is stacked in a zigzag form while being folded in a form of alternating reciprocating motion on the left side of the stacking axis and on the right side of the stacking axis based on the stacking axis. In addition, stacking means that the first electrode and the second electrode are alternately arranged between the folds of the stacked diaphragms. Here, the stacking axis means a virtual axis parallel to the direction in which the first electrode, the diaphragm, and the second electrode are stacked and passing through the center of the stack in which the electrodes and the diaphragm are stacked.

[0039] That is, the configuration in which the first electrode and the second electrode are alternately arranged between the corrugations of the diaphragm means that the diaphragms are stacked in the direction of the stacking axis while overlapping in a zigzag form, and the first electrode and the second electrode are each alternately inserted one by one in the space (between the diaphragms) generated when the diaphragms overlap.

[0040] <Method of Manufacturing Electrode Assembly>

[0041] An exemplary embodiment of the present invention provides a method for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode.

[0042] The method for manufacturing an electrode assembly according to the present invention includes a step of inductively heating a stacked member between a stacking process as a step of manufacturing a stacked member and a heating and pressing step as a step of heating and pressing the stacked member, and a step of inductively heating an electrode joint portion of the inductively heated stacked member.

[0043] The heating and pressing step includes a lower plate on which the electrode assembly to be heated and pressed is placed and to which heat is applied, and an upper plate corresponding to the lower plate and to which heat is applied. The lower plate and the upper plate may be a pressing block configured in a pair.

[0044] In the heating and pressing step of heating and pressing the electrode assembly, the electrodes located at the outermost sides of the stack (the uppermost and lowermost sides of the stack) are in direct physical contact with the lower plate and the upper plate, and therefore, more heat and pressure can be applied than the electrodes at the middle positions of the stack. This is because in the heating and pressing step, heating is performed while pressing is performed in a state where the uppermost and lowermost sides of the stack are in physical contact.

[0045] That is, in the heating and pressing steps, the electrodes in the stack may be heated to different temperatures according to their positions, so that the electrodes and the separator have different adhesion according to their positions. Therefore, there may be a problem that the performance of the electrode assembly becomes uneven according to the position.

[0046] Therefore, in the method for manufacturing an electrode assembly according to the present invention, more heat is applied to a local area, particularly a central portion in the stack, by the induction heating step. The heat applied to the local area is diffused throughout the electrode assembly. By heating and pressing the electrode assembly in the subsequent heating and pressing steps, the electrode assembly is uniformly heated as a whole.

[0047] In this process, since the thickness of the electrode joint included in the stack is thinner than the electrode and the diaphragm, the temperature of the electrode joint portion decreases faster than other portions after the induction heating step. As a result, even if the induction heating step and the heating and pressing step are performed, the problem that the vicinity of the electrode joint is not uniformly heated may occur. The present invention also performs a step of induction heating the electrode joint portion between the induction heating step and the heating and pressing step, thereby heating and pressing the electrode assembly in the heating and pressing step, so that the electrode assembly as a whole is heated more uniformly.

[0048] Thus, the deviation of the air permeability of the separator inside the electrode assembly manufactured through the heating and pressing steps is reduced, and the deviation of the adhesive force between the electrode and the separator is reduced, so that the electrode assembly with uniform performance can be manufactured.

[0049] In an exemplary embodiment of the present invention, the stacking step may include supplying the first electrode to the stacking stage; supplying the second electrode to the stacking stage; and supplying the separator to the stacking stage.

[0050] In this specification, "induction heating" refers to heating a target object by using an electromagnetic induction phenomenon. In this way, Joule heat is generated in the target object by an induced current generated in the target object by the electromagnetic induction phenomenon. Therefore, compared with a direct heating method that heats a target object while directly contacting the target object, induction heating is a heating method that can locally heat a target object even at a certain distance from a heating element.

[0051] The coil may be used to perform induction heating, which may be defined as an "induction heating coil". The induction heating method has the advantage that it is easy to control the amount of heat and time applied to the heating target. In addition, the induction heating method is even capable of non-contact heating, so the heating target may not be damaged.

[0052] In this specification, "induction heating step" may mean locally heating a stack by using an electromagnetic induction heating phenomenon. The locally heated stack may have an electrode arranged in a central portion of the stack. When a direct heating method is used, the uppermost or lowermost electrode of the electrode assembly may be heated more than the central electrode of the electrode assembly. However, in a method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention, the central portion of the electrode assembly is first selectively heated by an induction heating method, and then the electrode assembly is heated by a direct heating method in a subsequent heating and pressing step, so that the electrode assembly can be finally heated uniformly.

[0053] In this specification, the "electrode joint induction heating step" uses the electromagnetic induction heating phenomenon like the induction heating step, and can be distinguished from the induction heating step in that the heating target is the electrode joint portion included in the electrode of the stack. That is, the target to be locally heated may be the electrode joint. Since the thickness of the electrode joint is relatively very thin compared to the thickness of the electrode and the diaphragm, the temperature on the surface of the electrode joint may be reduced first after the induction heating step. For this reason, the temperature of the electrode joint portion may become relatively uneven during the heating and pressing steps. However, in a method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention, before performing the heating and pressing steps after the induction heating step, the electrode joint whose temperature has been relatively reduced is additionally heated by the electrode joint induction heating method, so that the electrode assembly can be uniformly heated in the subsequent heating and pressing steps.

[0054] In an exemplary embodiment of the present invention, in the electrode tab induction heating step, at least one of the first electrode tab and the second electrode tab may be induction heated using an induction heating coil.

[0055] In an exemplary 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 terminal and the second electrode terminal by a predetermined distance. When the induction heating coil is in contact with the electrode terminal (the distance between the electrode terminal and the induction heating coil is 0 mm), the induction heating coil may transfer as much heat as possible, so that the temperature of the electrode terminal may be increased even if the induction heating is performed in a short time.

[0056] Furthermore, when the induction heating coil is spaced apart from the electrode tab by a predetermined distance, the temperature of the electrode tab may be increased without damaging the electrode tab due to heat generated from the induction heating coil.

[0057] In an exemplary embodiment of the present invention, the predetermined distance may be 15 mm or less. More specifically, in an exemplary embodiment of the present invention, the predetermined distance may be greater than 0 mm and equal to or less than 15 mm, preferably equal to or greater than 0.05 mm and equal to or less than 10 mm, and more preferably equal to or greater than 0.3 mm and equal to or less than 5 mm. When the above distance is met, the electrode joint can be inductively heated without damaging the electrode joint, as described above.

[0058] In an exemplary embodiment of the present invention, the electrode joint induction heating step can be performed for 1 second to 60 seconds, preferably 5 seconds to 40 seconds, and more preferably 10 seconds to 30 seconds. However, the electrode joint induction heating time can be selected considering the induction heating temperature in the induction heating step, the degree to which the electrode assembly is unevenly heated in the heating and pressing steps, etc.

[0059] In an exemplary embodiment of the present invention, in the electrode tab induction heating step, the electrode tab may be heated at a temperature of 40° C. or higher and 90° C. or lower, and preferably at a temperature of 50° C. or higher and 80° C. or lower. When the electrode tab is induction heated within the above temperature range, the electrode tab may be heated without being damaged.

[0060] In an exemplary embodiment of the present invention, in the induction heating step, a portion of the stack is inductively heated, and the heat is diffused to the entire stack to heat the entire stack.

[0061] In an exemplary embodiment of the present invention, in the induction heating step, the first electrode or the second electrode of the stack may be inductively heated. More specifically, in an exemplary embodiment of the present invention, in the induction heating step, the first electrode or the second electrode arranged in the center of the stack may be inductively heated. In the heating and pressing step, a relatively small amount of heat may be applied to the first electrode or the second electrode arranged in the center of the stack compared to the first electrode or the second electrode arranged at the outermost side of the stack. However, heat may first be applied to the first electrode or the second electrode arranged in the center of the stack by the induction heating step, and then the heating and pressing step may be performed so that heat may be applied uniformly throughout the stack.

[0062] In this specification, induction heating may include induction heating of the entire surface of the stack in addition to induction heating of only a partial area (local area) of the surface of the stack. However, even when only a partial area is induction heated, the purpose of the present invention can be achieved. In addition, induction heating may be different from heating and pressing in that no pressure is applied to the stack.

[0063] In an exemplary embodiment of the present invention, the induction heating step may be performed for 1 to 60 seconds, preferably 5 to 40 seconds, and more preferably 10 to 30 seconds. The induction heating time may be selected in consideration of the degree to which the electrode assembly is unevenly heated in the heating and pressing steps.

[0064] In an exemplary embodiment of the present invention, the induction heating step may inductively heat the stack using an induction heating coil.

[0065] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may include a step of transferring the stack to a heating and pressing step after the stacking step. In the transferring step, the stack may be gripped by a gripper so as to transfer the stack.

[0066] The clamp may maintain a clamp against the stack during the heating and pressing steps.

[0067] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may inductively heat the stack while transferring the stack from the stacking stage to the heating and pressing unit.

[0068] More specifically, in an exemplary embodiment of the present invention, the induction heating step may further include clamping the stack with a clamp including an induction heating coil and transferring the stack between the stacking step and the heating and pressing step. The induction heating step may be performed using the clamp during the transferring step.

[0069] More specifically, in an exemplary embodiment of the present invention, the induction heating step may include clamping the stack with a clamp including an induction heating coil; transferring the clamped stack to the heating and pressing step; and inductively heating the stack with the induction heating coil of the clamp while transferring the stack.

[0070] That is, since the induction heating coil is built in or attached to the holder, there is no need to provide a separate space for induction heating, thereby making the electrode assembly manufacturing equipment compact.

[0071] In addition, in an exemplary embodiment of the present invention, the induction heating step may further include transferring the stack to an induction heating device including an induction heating coil between the stacking step and the heating and pressing step, and the induction heating step may be performed in the induction heating device. As long as the induction heating device is capable of performing induction heating, a method commonly used in the relevant field may be used.

[0072] More specifically, in an exemplary embodiment of the present invention, the induction heating step may include clamping the stack with a clamper and transferring the clamped stack to an induction heating device including an induction heating coil; and induction heating the stack in the induction heating device. More specifically, the induction heating may induction heat the stack while the stack is clamped by the clamper. In this way, after the stack is clamped by the clamper, it can be transferred to the heating and pressing step through the induction heating step without unnecessary pauses. That is, it is possible to avoid repeatedly clamping and releasing the stack between adjacent steps.

[0073] That is, the induction heating coil is not installed inside or outside the holder, but the induction heating device separated from the holder may include the induction heating coil. When a separate induction heating device is used, the induction heating step can be performed even when the thickness of the stack including the electrode and the diaphragm becomes thick.

[0074] Furthermore, when a separate induction heating device is used in the present invention, the electrode tab portion protruding from the electrode may be additionally heated by the induction heating device, and thus the temperature difference between the electrode tab and the electrode may be reduced.

[0075] In an exemplary embodiment of the present invention, in the induction heating step, the stack may be heated at a temperature of 40° C. or more and 90° C. or less, preferably 50° C. or more and 80° C. or less. When the stack is inductively heated within the above temperature range, the stack may be heated without damaging the electrodes and the separator inside the stack.

[0076] In an exemplary embodiment of the present invention, the induction heating coil may be in contact with the stack or spaced apart from the stack by a predetermined distance.

[0077] When the induction heating coil is in contact with the stack (the distance between the stack and the induction heating coil is 0 mm), the induction heating coil can transfer as much heat as possible, so the internal temperature of the stack can be increased even if induction heating is performed in a short time.

[0078] Furthermore, when the induction heating coil is spaced apart from the stack by a predetermined distance, the internal temperature of the stack may be increased without damaging the stack due to heat generated from the induction heating coil.

[0079] In an exemplary embodiment of the present invention, the predetermined distance may be 15 mm or less. More specifically, in an exemplary embodiment of the present invention, the predetermined distance may be greater than 0 mm and equal to or less than 15 mm, preferably equal to or greater than 0.05 mm and equal to or less than 10 mm, and more preferably equal to or greater than 0.3 mm and equal to or less than 5 mm. When the above distance is met, the electrode can be inductively heated without damaging the stack, as described above.

[0080] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may further include a step of removing the induction heating unit from the moving line of the electrode assembly before the heating and pressing step. Thus, physical collision between the induction heating unit and the heating and pressing unit can be prevented.

[0081] Furthermore, physical collision between the holder and the heating and pressing unit can also be prevented by the first heating and pressing step and the second heating and pressing step described later.

[0082] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may further include a waiting step between the induction heating step and the heating and pressing step of allowing the stack to wait for a certain period of time in an atmospheric state. The atmospheric state means that after the induction heating step, the induction heating is stopped for a certain period of time to wait for the heat applied to the stack by the induction heating to diffuse throughout the stack.

[0083] By the waiting step, the heat transferred to the partial area of ​​the stack can be transferred to the entire area of ​​the stack. In this way, by intentionally stopping the induction heating of the stack for a certain period of time before performing the heating and pressing steps, the heat transferred to the stack by induction heating is evenly diffused throughout the stack.

[0084] Thereafter, by heating and pressing the stack through subsequent heating and pressing steps, the thickness uniformity of the electrode may be increased throughout the electrode assembly.

[0085] In an exemplary embodiment of the present invention, the waiting step may be performed for 3 seconds or longer and 60 seconds or shorter, preferably 5 seconds or longer and 45 seconds or shorter, and more preferably 10 seconds or longer and 40 seconds or shorter.

[0086] When the above time range is met, it is possible to ensure that the heat transferred to the partial area of ​​the electrode inside the stack by induction heating can be evenly distributed throughout the stack. That is, if the waiting step is performed for less than 3 seconds, the heat transferred to the partial area of ​​the stack is difficult to transfer throughout the electrode. On the other hand, if the waiting step is performed for longer than 60 seconds, the temperature of the electrode raised by the transferred heat may decrease, and therefore, there may be a problem of reduced effect of induction heating.

[0087] The waiting time may be changed according to the heating time and heating temperature range of the stack in the subsequent heating and pressing steps.

[0088] In an exemplary embodiment of the present invention, for the manufacturing steps of a stack in which the first electrode and the second electrode are alternately arranged between the folds of the folded diaphragm, the commonly used techniques in the relevant field can be used. For example, the process of stacking the first electrode on the stacking table, covering the first electrode with the diaphragm, stacking the second electrode on the upper surface of the diaphragm, folding the diaphragm to cover the second electrode, and stacking the first electrode on the upper surface of the diaphragm can be repeated. In this exemplary embodiment, this is referred to as a zigzag stacking method. In this case, for the process of moving the diaphragm while covering the first electrode or the second electrode placed on the diaphragm, a method of moving the stacking table left and right, a method of moving the diaphragm left and right, a method of rotating the stacking table, etc. can be applied.

[0089] In the zigzag stacking method, a holding mechanism may clamp the stack to maintain the alignment of the stack during the process of stacking the first electrode, the second electrode, and the separator.

[0090] In this specification, a "holding mechanism" is a tool for clamping a stack placed on a stacking table to stack the first electrode or the second electrode in a zigzag stacking method, and is different from a clamper for clamping the stack in the heating and pressing step.

[0091] In an exemplary embodiment of the present invention, the diaphragm may be supplied in the form of a diaphragm sheet. That is, the diaphragm to be provided additionally may be provided in a continuous form. In addition, the "upper surface" may refer to a surface opposite to the surface of the stacking station on which the diaphragm or electrode is placed.

[0092] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may include a heating and pressing step of heating and pressing the stacked member subjected to induction heating as described above. In the heating and pressing step, the stacked member may be heated while pressing the stacked member in the direction of the stacking axis. In addition, the heating and pressing step may be performed by a heating and pressing unit described later.

[0093] Furthermore, in an exemplary embodiment of the present invention, the heating and pressing step may include moving the stack between a pair of pressing blocks including a pressing heater; surface pressing the stack by moving the pair of pressing blocks relative to each other in a stack axis direction; and heating the stack.

[0094] The pair of pressing blocks may include a lower plate and an upper plate facing the lower plate.

[0095] Alternatively, in an exemplary embodiment of the present invention, the heating and pressing step may include moving the stack between a pair of pressing blocks; surface pressing the stack by moving the pair of pressing blocks in the direction of the stack axis; and heating the stack by a separately provided pressing heater.

[0096] That is, the press heater may be included in the press block or may be provided as a separate configuration.

[0097] The method for manufacturing an electrode assembly according to the exemplary embodiment of the present invention may further include a step of releasing clamping of the clamper before the heating and pressing steps.

[0098] That is, the step of releasing the clamping of the clamper may include stopping the pressing of the clamper against the upper surface of the stack; and separating the clamper from the stack.

[0099] Furthermore, the step of moving the stacked member between the pair of pressing blocks including the pressing heater in the heating and pressing step may include not only the case of moving only the stacked member itself, but also the case of moving the stacked member together with the stacking table while the stacked member is placed on the stacking table. In this case, the target to be heated and pressed by the pair of pressing blocks and the pressing heater may refer to the stacked member and the stacking table.

[0100] In an exemplary embodiment of the present invention, in the heating and pressing step, the stack may be heated and pressed for 5 to 60 seconds at a temperature of 50 to 90° C. and a pressure of 0.5 to 6.0 MPa. More preferably, the stack may be heated and pressed for 5 to 30 seconds at a temperature of 65 to 90° C. and a pressure of 1.0 to 6.0 MPa. More preferably, the stack may be heated and pressed for 7 to 25 seconds at a temperature of 65 to 85° C. and a pressure of 3 to 5.5 MPa.

[0101] When heating and pressing are performed while satisfying the above conditions, the adhesion between the first electrode and the separator and between the separator and the second electrode can be improved without damaging the first electrode, the separator, and the second electrode. Therefore, the performance of the electrode assembly can be improved.

[0102] In an exemplary embodiment of the present invention, the heating and pressing step is not performed while the induction heating step is performed.

[0103] In an exemplary embodiment of the present invention, the induction heating step may include measuring a temperature distribution on a surface of the stack; setting an induction heating temperature for the stack according to the measured temperature distribution; and inductively heating the stack based on the set induction heating temperature. That is, by adjusting the induction heating temperature of the stack according to the measured temperature distribution on the upper surface of the stack, the electrode can be inductively heated in an efficient manner without using unnecessary energy.

[0104] In an exemplary embodiment of the present invention, the electrode joint induction heating step may be performed between the induction heating step and the heating and pressing step. That is, the electrode joint induction heating step is performed after the induction heating step. This is because, even if the induction heating step is performed, additional heating is required due to the rapid temperature change of the electrode joint portion. Because this is to heat the stack including the electrode joint to a uniform temperature in the heating and pressing step, the electrode joint induction heating step is performed before the heating and pressing step.

[0105] That is, the method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may sequentially perform an induction heating step, an electrode joint induction heating step, and a heating and pressing step. In addition, the method may also perform a waiting step between the induction heating step and the electrode joint induction heating step.

[0106] <Electrode assembly manufacturing equipment>

[0107] An exemplary embodiment of the present invention provides an apparatus for manufacturing an electrode assembly including a first electrode, a separator, and a second electrode (electrode assembly manufacturing apparatus).

[0108] For reference, a semi-finished product state in which a first electrode, a separator, and a second electrode are repeatedly stacked is referred to as a stack, and a separator winding process is performed on the semi-finished product so that a different component can be classified as an electrode assembly. In addition, at least one of the first electrodes of the stack may include a first electrode tap, and at least one of the second electrodes of the stack may include a second electrode tap.

[0109] That is, the finally manufactured electrode assembly may further include at least one first electrode tap and at least one second electrode tap.

[0110] The electrode assembly manufacturing equipment includes an induction heating unit and an electrode joint induction heating unit. The induction heating unit of the electrode assembly manufacturing equipment of the present invention performs the above-mentioned induction heating step, and the electrode joint induction heating unit performs the above-mentioned electrode joint induction heating step. That is, when the electrode assembly manufacturing equipment according to the present invention is used, the stack including the first electrode, the diaphragm and the second electrode is uniformly heated during the heating and pressing steps performed by the heating and pressing unit, so that uniform adhesion can be ensured between the layers in the stack. Thereby, the permeability deviation of the diaphragm according to the stacking position of the electrode assembly, the diaphragm thickness variation deviation, and the adhesion deviation are reduced, so that an electrode assembly with uniform performance can be manufactured while reducing the volume of the electrode assembly. In addition, an electrode assembly with an increased energy density per unit volume can be manufactured.

[0111] The electrode assembly manufacturing apparatus according to the present invention may further include: a membrane supply unit configured to supply a membrane to the stacking stage; a first electrode supply unit configured to supply a first electrode to the stacking stage; and a second electrode supply unit configured to supply a second electrode to the stacking stage.

[0112] In an exemplary embodiment of the present invention, the induction heating unit may be a clamp that clamps the stack so as to transfer the stack to the heating and pressing unit. The clamp may include an induction heating coil. As described above, the induction heating coil may be built into the clamp or may be installed outside the clamp. When the clamp is used as an induction heating unit, a process space for installing the induction heating unit may be saved. In addition, the process time may also be shortened because induction heating may be performed while transferring the stack. The clamp may perform the function of clamping the stack while transferring the stack from the stacking station to the heating and pressing unit.

[0113] In an exemplary embodiment of the present invention, the induction heating unit may be installed separately from the clamp. That is, in an exemplary embodiment of the present invention, a clamp for holding and moving the stack may be further included between the stacking stage and the induction heating unit, and the induction heating unit may inductively heat the stack while holding the stack with the clamp. Thereafter, the clamp may transfer the inductively heated stack to the heating and pressing unit while holding the inductively heated stack, thereby enabling the stack to be transferred without unnecessarily holding or releasing the stack in an adjacent step.

[0114] In an exemplary embodiment of the present invention, the induction heating unit may be installed separately from the gripper for conveying the stack. That is, the induction heating unit may include: a first induction heating device including an induction heating coil; and a first device moving unit configured to move the first induction heating device to the surface of the stack. When the first device moving unit moves the first induction heating device to an appropriate distance from the stack, the first induction heating device may inductively heat the stack. When the induction heating of the stack is completed, the first device moving unit may separate the first induction heating device from the stack.

[0115] In this case, as described above, there is an advantage that it is easy to apply even if the thickness of the stack is thick, and there is an advantage that the induction heating unit can be used even when the electrode tab is inductively heated.

[0116] In this specification, a "unit" refers to an interface that performs a specific function within an electrode assembly manufacturing apparatus.

[0117] The induction heating coil of the electrode assembly manufacturing apparatus according to the exemplary embodiment of the present invention may be in contact with the stack or spaced apart from the stack by a predetermined distance. In this case, the predetermined distance may be 15 mm or less, more specifically, greater than 0 mm and equal to or less than 15 mm, preferably equal to or greater than 0.05 mm and equal to or less than 10 mm, and more preferably equal to or greater than 0.3 mm and equal to or less than 5 mm.

[0118] Advantages achieved when the induction heating coil is in contact with the stack and when the induction heating coil is spaced apart from the stack by a predetermined distance are as described in the method for manufacturing an electrode assembly.

[0119] In an exemplary embodiment of the present invention, the induction heating unit may include an induction heating coil and an induction heating plate.

[0120] In addition, the induction heating coil may be included inside the induction heating plate including the non-conductive material. The induction heating plate may include an AC generator for providing an alternating current to the induction heating coil, and may be used to protect the induction heating coil. The non-conductive material is used as the material of the induction heating plate to prevent the current induced by the induction heating coil from also being generated in the induction heating plate.

[0121] The induction heating plate can be a mold made of a non-conductive material. The non-conductive material can be epoxy resin, but is not limited thereto.

[0122] Furthermore, the induction heating coil and the induction heating plate may constitute a set.

[0123] The induction heating unit may include an alternating current generator, but is not limited thereto, and any device capable of generating an electromagnetic induction phenomenon with respect to the induction heating coil may be applied.

[0124] According to an exemplary embodiment of the present invention, the electrode assembly manufacturing equipment may also include a first control unit, which is configured to measure the temperature distribution on the surface of the stack, set the induction heating temperature for the stack according to the measured temperature distribution, and determine whether to stop the induction heating of the stack based on the induction heating temperature and induction heating time for the stack.

[0125] Furthermore, the first control unit may be further configured to adjust an induction heating time for the stack.

[0126] That is, the conditions for performing the induction heating step and the conditions for performing the waiting step may be set by the first control unit. For each condition, the contents described in the method for manufacturing an electrode assembly may be applied.

[0127] In an exemplary embodiment of the present invention, the electrode joint 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 the first electrode joint portion or the second electrode joint portion. When the second device moving unit moves the second induction heating device to an appropriate distance from the electrode joint, the second induction heating device may inductively heat the electrode joint. When the induction heating of the electrode joint is completed, the second device moving unit may separate the second induction heating device from the electrode joint. The process may be performed by a second control unit, which performs a function of controlling the operation of the electrode joint induction heating unit according to the conditions of the above-mentioned electrode joint induction heating step.

[0128] In an exemplary 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 connector and the second electrode connector by a predetermined distance. In this case, the predetermined distance may be 15 mm or less, more specifically, greater than 0 mm and equal to or less than 15 mm, preferably equal to or greater than 0.05 mm and equal to or less than 10 mm, and more preferably equal to or greater than 0.3 mm and equal to or less than 5 mm.

[0129] Advantages achieved when the induction heating coil is in contact with the electrode tab and when the induction heating coil is spaced apart from the electrode tab by a predetermined distance are as described in the method for manufacturing an electrode assembly.

[0130] In an exemplary embodiment of the present invention, the electrode joint induction heating unit may include an induction heating coil and an induction heating plate. The description of the induction heating coil and the induction heating plate of the induction heating unit may be applied to the description of the induction heating coil and the induction heating plate of the electrode joint induction heating unit. However, some shapes and sizes may be different depending on the size difference and position of the heating target.

[0131] In an exemplary embodiment of the present invention, the heating and pressing unit may include a pair of pressing blocks, and may be configured to surface-press the stack while moving the pair of pressing blocks in directions facing each other.

[0132] The heating and pressing unit includes a pair of pressing blocks and a pressing heater for heating the pressing blocks. While the pressing heater heats the pressing blocks, the pair of pressing blocks move in directions facing each other so that the stack placed between the pressing blocks can be pressed by the surface.

[0133] In this case, a press heater may be included in the pair of pressing blocks.

[0134] In another exemplary embodiment of the present invention, the heating and pressing unit may be two heating and pressing units to be divided. That is, the heating and pressing unit may include a first heating and pressing unit and a second heating and pressing unit.

[0135] Reference Figure 7 , the first heating and pressing unit may include a pair of first pressing blocks. The pressing surfaces of the pair of first pressing blocks may include a groove corresponding to the clamp so as to press the stack while the clamp clamps the stack. The pressing surface other than the groove may be a plane. The second heating and pressing unit may include a pair of second pressing blocks. The pressing surface of the pair of second pressing blocks may be set to a plane. That is, when the stack is placed on the pressing surface of the pressing block, the second pressing blocks may move relative to each other to heat and press the stack.

[0136] When the heating and pressing unit is divided into two units as described above, it is possible to prevent the loss of adhesive force between the layers inside the stack due to cooling while the heated stack is being conveyed.

[0137] The conditions for heating and pressing the stack by the heating and pressing unit are the same as those of the above-described heating and pressing step.

[0138] The electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention can be configured so that the induction heating unit, the electrode joint induction heating unit, and the heating and pressing unit are operated in sequence. That is, as described above, the apparatus can be operated so that the electrode joint induction heating step can be performed between the induction heating step and the heating and pressing step.

[0139] In addition, in an exemplary embodiment of the present invention, the electrode assembly may have a rated capacity of 50 Ah to 200 Ah, preferably a rated capacity of 50 Ah to 150 Ah, and more preferably a rated capacity of 60 Ah to 140 Ah.

[0140] The electrode assembly may have an overall length to overall width ratio of 5 to 10, preferably 5 to 8. Specifically, the electrode assembly may have an overall length of 400 to 600 mm, an overall width of 50 to 150 mm, preferably an overall length of 500 to 600 mm and an overall width of 50 to 100 mm.

[0141] An exemplary embodiment of the present invention includes a first pressing unit and a second pressing unit, the first pressing unit including induction heating, and the second pressing unit is used to heat and press the induction-heated electrode assembly after the stack is assembled on the stacking table to complete the electrode assembly. In particular, in the case of a large-sized electrode assembly such as an electrode assembly, when heated in a direct contact method, a severe temperature deviation may occur depending on the position inside the electrode assembly, especially between the outermost side of the electrode assembly and the central part of the electrode assembly. However, when an exemplary embodiment of the present invention is applied to a large-sized electrode assembly, the following advantages can be shown: even if the thickness of the electrode assembly is thick, the entire electrode assembly is uniformly heated regardless of the position within the electrode assembly.

[0142] In an exemplary embodiment of the present invention, the stacking table may include a table body on which the stack is placed and a driving unit configured to drive the table body. The table body may include a stacking table heater capable of heating the stack to a predetermined temperature when the stack is placed.

[0143] In an exemplary embodiment of the present invention, the first electrode supply unit may include at least one of a first electrode seating table, a first electrode roller, a first cutter, a first conveyor belt, and a first electrode supply head.

[0144] Furthermore, the first electrode placement stage may include a first electrode heater for heating the first electrode placed on the first electrode placement stage to a predetermined temperature.

[0145] In an exemplary embodiment of the present invention, the second electrode supply unit may include at least one of a second electrode placement table, a second electrode roller, a second cutter, a second conveyor belt, and a second electrode supply head.

[0146] Furthermore, the second electrode placement stage may include a second electrode heater for heating the second electrode placed on the second electrode placement stage to a predetermined temperature.

[0147] In an exemplary embodiment of the present invention, the first electrode stacking unit may include a first adsorption head that vacuum-adsorbs the first electrode placed on the first electrode placement stage. The first electrode may be moved from the first electrode placement stage to the stacking stage by the first electrode stacking unit.

[0148] The second electrode stacking unit may include a second adsorption head for vacuum adsorption of the second electrode placed on the second electrode placement stage. The second electrode may be moved from the second electrode placement stage to the stacking stage by the second electrode stacking unit.

[0149] In an exemplary embodiment of the present invention, the first electrode may be a positive electrode, and the second electrode may be a negative electrode.

[0150] In an exemplary embodiment of the present invention, the first electrode may be a cathode, and the second electrode may be a cathode.

[0151] In an exemplary embodiment of the present invention, for the current collectors, active materials, conductive materials, etc. used for the positive and negative electrodes, materials known in the art may be used without limitation, and for the methods for manufacturing the positive and negative electrodes, methods known in the prior art may be used without limitation.

[0152] In an exemplary embodiment of the present invention, for the separator, an active material known in the art can be used without limitation, and for the method of manufacturing the separator, a method known in the related art can be used without limitation. However, in an exemplary embodiment of the present invention, the separator may include a porous polymer substrate and an organic / inorganic composite porous coating formed on at least one surface of the polymer substrate, and the organic / inorganic composite porous coating may include a particle binder resin and inorganic particles.

[0153] In an exemplary embodiment of the present invention, the particle binder resin may include at least one selected from the group consisting of a fluorine-based polymer, acrylic polymer particles, and hybrid polymer particles of acrylic polymer particles and acrylic polymers.

[0154] In an exemplary embodiment of the present invention, the fluorine-based polymer may be a homopolymer of vinylidene fluoride, a copolymer of vinylidene fluoride and another polymerizable monomer, or a mixture of two or more thereof.

[0155] In an exemplary embodiment of the present invention, the inorganic particles may be Al 2 O 3 , but are not limited thereto.

[0156] Due to the inclusion of the organic / inorganic composite porous coating layer, an electrode assembly having increased adhesion between an electrode and a separator may be manufactured by applying the induction heating step and the heating and pressing step described in the electrode assembly manufacturing apparatus and / or the electrode assembly manufacturing method.

[0157] Hereinafter, an electrode assembly manufacturing apparatus and an electrode assembly manufacturing method according to an exemplary embodiment of the present invention will be described in more detail. The following description assumes that the electrode assembly of the present invention is zigzag stacked.

[0158] Figure 1 is a cross-sectional view showing a process flow of an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention, and Figure 2 is a plan view showing a process flow of an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention. Figure 1 Omitted Figure 2 The holding mechanism 170, the heating and pressing unit 180 and the induction heating unit 190 shown in FIG. Figure 2 Omitted Figure 1 The diaphragm supply unit 120 shown in FIG.

[0159] Reference Figures 1 to 3 , the electrode assembly manufacturing apparatus 100 according to the exemplary embodiment of the present invention includes a separator supply unit 120 supplying a separator 14 to the stacking stage 110, a first electrode supply unit 130 supplying a first electrode 11 to the stacking stage 110, and a second electrode supply unit 140 supplying a second electrode 12 to the stacking stage 110. The separator 14, the first electrode 11, and the second electrode 12 may each be supplied to the stacking stage 110 while being heated in the first electrode supply unit 130 and the second electrode supply unit 140.

[0160] In addition, the electrode assembly manufacturing equipment 100 according to the exemplary embodiment of the present invention includes a first electrode stacking unit 150 for stacking the first electrode 11 supplied by the first electrode supply unit 130 on the stacking stage 110, and a second electrode stacking unit 160 for stacking the second electrode 12 supplied by the second electrode supply unit 140 on the stacking stage 110. In this case, the diaphragm 14 supplied by the diaphragm supply unit 120 is stacked in a zigzag form while alternately reciprocating on the left and right sides of the stacking axis based on the stacking axis. In this case, any one of the first electrode 11 and the second electrode 12 is alternately inserted into the space (between the diaphragm and the diaphragm) generated when the diaphragm 14 is folded, and as a result, a stack in which the first electrode 11, the diaphragm 14, the second electrode 12 and the diaphragm 14 are repeatedly stacked is placed on the stacking stage 110.

[0161] The diaphragm supply unit 120 may include a diaphragm heating unit 121 and a diaphragm roller 122. The diaphragm heating unit 121 may be selectively applied.

[0162] More specifically, the first electrode supply unit 130 may include a first electrode seating stage 131, a first electrode heater (not shown), a first electrode roller 133, a first cutter 134, a first conveyor belt 135, and a first electrode supply head 136. The first electrode heater (not shown) may be selectively applied.

[0163] In addition, the second electrode supply unit 140 may include a second electrode seating stage 141, a second electrode heater (not shown), a second electrode roller 143, a second cutter 144, a second conveyor belt 145, and a second electrode supply head 146. The second electrode heater (not shown) may be selectively applied.

[0164] The first electrode stacking unit 150 stacks the first electrode 11 on the stacking stage 110. In this case, the first electrode stacking unit 150 may include a first adsorption head 151, a first head heater (not shown), and a first moving unit 153. In addition, the second electrode stacking unit 160 stacks the second electrode 12 on the stacking stage 110. The second electrode stacking unit 160 may include a second adsorption head 161, a second head heater (not shown), and a second moving unit 163.

[0165] The first electrode stack unit 150 and the second electrode stack unit 160 may further include a heater (not shown) for preheating the first electrode and the second electrode according to circumstances.

[0166] In addition, the electrode assembly manufacturing apparatus 100 according to the exemplary embodiment of the present invention may further include a holding mechanism 170 for fixing the first electrode 11 and the second electrode 12 when the first electrode 11 and the second electrode 12 are stacked on the stacking stage 110. In addition, the electrode assembly manufacturing apparatus 100 according to the exemplary embodiment of the present invention includes a heating and pressing unit 180 that heats and presses the stack placed on the stacking stage 110 to combine the first electrode 11, the separator 14, and the second electrode 12 with each other.

[0167] In addition, the electrode assembly manufacturing apparatus 100 according to the exemplary embodiment of the present invention further includes an induction heating unit 190, which induction heats the stack to transfer heat to the electrodes in the stack. In addition, a control unit (not shown) for controlling, for example, whether to start the induction heating unit 190 may be further included. Thus, the electrode assembly manufacturing apparatus 100 may be finally manufactured. Figure 3 The electrode assembly 10 is shown.

[0168] Figure 3 is a cross-sectional view schematically illustrating an electrode assembly manufactured by an electrode assembly manufacturing apparatus and an electrode assembly manufacturing method according to an exemplary embodiment of the present invention.

[0169] refer to Figure 3 The electrode assembly 10 may have a stacked form including a separator (14) folded and stacked in a zigzag form and a first electrode (11) or a second electrode (12) alternately inserted into a space between folds of the separator (14).

[0170] In this case, the electrode assembly 10 may be provided in a form in which the separator 14 surrounds the outermost side of the stack. However, it should be noted that the configuration of the electrode assembly 10 is not limited to Figure 3 .

[0171] Figure 4 and Figure 5is a view schematically illustrating an operation process of an induction heating unit according to an exemplary embodiment of the present invention.

[0172] Specifically, Figure 4 The case where the induction heating unit 190 is a clamp 51 is shown. The clamp 51 may include an induction heating coil (not shown). The clamp 51 may perform induction heating on the stack S while clamping the stack S. While performing induction heating by the clamp 51, the stack S may be transferred to the heating and pressing unit 180. In the heating and pressing unit 180, the stack S may be heated and pressed. In this case, before the stack S is heated and pressed in the heating and pressing unit 180, a waiting process (step) of stopping the induction heating of the stack S and making the stack wait for a certain period of time may be performed. In this case, the conditions of the waiting process may be set by a control unit (not shown).

[0173] Figure 5 Another exemplary embodiment of induction heating is shown, showing the use of an induction heating unit 190 provided separately from the clamp 51 to inductively heat the stack S. In this case, the stack S is inductively heated after being moved to the induction heating device. When the induction heating is completed, it can be as follows Figure 4 As shown, the stack S is heated and pressed in the heating and pressing unit 180. In this case, before the stack S is heated and pressed in the heating and pressing unit 180, a waiting process (step) of stopping the induction heating of the induction-heated stack S and making the stack wait for a certain period of time may be performed. Even in this case, the conditions of the waiting process may be controlled by a control unit (not shown). Figure 5 As shown, the waiting process may be performed in a state in which the stack S leaves the induction heating unit 190 and is clamped by the clamper 51 .

[0174] Figure 6 Schematically illustrates the operation process of the electrode joint induction heating unit according to an exemplary embodiment of the present invention. As an exemplary embodiment, Figure 6 The stack S is shown to be inductively heated using an induction heating unit 190 provided separately from the clamp 51. Figure 5As shown, the stack S may be subjected to an induction heating step, a waiting step, and a heating and pressing step. In this case, the first electrode joint 10a portion may be inductively heated by the electrode joint induction heating unit 193 between the waiting step and the heating and pressing step. Thus, the temperature of the electrode joint portion whose temperature has been relatively reduced may be increased, and the stack S may be pressed at a uniform temperature in the heating and pressing step. In this case, a plurality of first electrode joints may be included in the stack. In addition, the stack S may include a second electrode joint (not shown), and the induction heating of the second electrode joint may be applied in the same manner as the induction heating of the first electrode joint. A plurality of second electrode joints may also be included in the stack. The above conditions may be applied to the conditions of each step.

[0175] Figure 7 An induction heating unit according to an exemplary embodiment of the present invention is schematically shown. Figure 7 , the induction heating unit 190 may include an induction heating coil 191 and an induction heating plate 192. More specifically, the induction heating coils 191a and 191b may be built into the induction heating plates 192a and 192b. The induction heating coil 191 may have a U-shape. The induction heating coils 191a and 191b may face each other. The specific arrangement of the induction heating coil 191 may be as follows Figure 7 As shown, but not limited to.

[0176] When an alternating current is applied to the induction heating coil 191, an induced current may be generated in the metal electrode in the electrode assembly, and thus the electrode is heated by the induced current. Thus, induction heating may be generated targeting the electrode arranged in a specific layer in the electrode assembly.

[0177] In the present invention, targeting the electrode arranged at the central portion of the electrode assembly which is particularly sensitive to heating in the heating and pressing step of heating and pressing the electrode assembly, induction heating is performed in advance before the heating and pressing step.

[0178] Figure 8 The configuration of the heating and pressing unit 50 is shown, and particularly the case in which the heating and pressing unit 50 includes a first heating and pressing unit 50 and a second heating and pressing unit 60 is shown.

[0179] Figure 8 (a) is a perspective view showing the first heating and pressing unit 50, and Figure 8 (b) is a perspective view showing the second heating and pressing unit 60 .

[0180] Reference Figure 8(a), the first heating and pressing unit 50 can heat and press the stack S in a state where the stack S is fixed by the clamp 51. The first heating and pressing unit 50 may include a pair of first pressing blocks 50a and 50b. In the pair of first pressing blocks 50a and 50b, except for the groove corresponding to the fixing portion 51b of the clamp 51, the pressing surfaces for pressing are all flat.

[0181] The clamper 51 may include a main body 51a corresponding to or greater than the length (x) and height (y) of the stack S, and a fixing portion 51b protruding from the main body 51a and holding the stack S. Here, the length (x) of the stack S refers to the longest part of the distance from one end to the other end of the stack S, the height (y) refers to the distance of the stack S in the stacking direction, and the width (z) may refer to the distance across the upper surface of the stack S horizontally.

[0182] The fixing portion 51 b may be positioned in a height direction of the body 51 a such that the fixing portion 51 b can contact the upper and lower surfaces of the stack S to fix the stack S.

[0183] Thereafter, the pair of first compacts 50 a and 50 b are moved in directions facing each other to heat and press the stack S. The electrodes and the separator inside the electrode assembly are stably combined by heating and pressing.

[0184] The first heating and pressing unit 50 may be a component that compensates for cooling while the induction-heated electrode assembly moves, and may be selectively provided. That is, in some cases, the first heating and pressing unit may be omitted.

[0185] Reference Figure 8 (b), the second heating and pressing unit 60 may finally heat and press the stack S that has been first heated and pressed by the first heating and pressing unit 50. The second heating and pressing unit 60 includes a pair of second pressing blocks 60a and 60b, and the pair of second pressing blocks 60a and 60b may move in directions facing each other to perform surface pressing on the stack S. In addition, in the pair of second pressing blocks 60a and 60b included in the second heating and pressing unit 60, the pressing surfaces for pressing in contact with the stack S may all be set to a flat surface.

[0186] The description of the electrode assembly manufacturing method according to the present invention can also be applied to the electrode assembly manufacturing apparatus according to the present invention, and vice versa.

[0187] <Electrode assembly>

[0188] In this specification, “the outermost side of the electrode assembly” means the uppermost position or the lowermost position in the stacking direction of the stack.

[0189] Furthermore, in this specification, “the middle of the electrode assembly” means a position located between the uppermost position and the lowermost position in the stacking direction of stacked elements based on the stacking axis and corresponding to the middle portion.

[0190] The exemplary embodiment of the present invention provides an electrode assembly including a first electrode, a separator and a second electrode manufactured according to the electrode assembly manufacturing apparatus and / or the electrode assembly manufacturing method according to the present invention. That is, the electrode assembly may be an electrode assembly stacked in a zigzag stacking method.

[0191] However, the electrode assembly may also have a laminated and folded (L&F) structure in which the electrode and the separator are wound, or a stacked and laminated (S&L) structure in which the electrode and the separator are stacked in sequence. That is, the present invention is applicable to various types of electrode assemblies because the present invention adds a process of heating and pressing the electrode assembly to improve the adhesion between the electrode and the separator in the electrode assembly after the electrode assembly is completed.

[0192] In an exemplary 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 heated and pressed, the volume of the electrode assembly is reduced compared to the case where the electrode and the separator are simply stacked and then packaged.

[0193] In particular, volume reduction of the electrode assembly may be achieved through the separator. In this specification, a configuration in which the separator is compressed after zigzag stacking means that the separator of the electrode assembly is compressed compared to the separator before compression.

[0194] That is, in an exemplary embodiment of the present invention, the compression rate of the diaphragm located at the outermost side of the electrode assembly is greater than the compression rate of the diaphragm located in the middle of the electrode assembly, and the difference in compression rate is 3%p (percentage point) or less, preferably 2%p or less, and more preferably 1.5%p or less.

[0195] In an exemplary embodiment of the present invention, the compression rate of the separator located at the outermost side of the electrode assembly may be 3% to 8%, preferably 4% to 8%.

[0196] In an exemplary embodiment of the present invention, the compression rate of the separator located in the middle of the electrode assembly may be 3% to 8%, preferably 4% to 8%.

[0197] In an exemplary embodiment of the present invention, the compression rate of the separator located at the outermost side of the electrode assembly can be 3% to 8%, preferably 4% to 8%, and the compression rate of the separator located in the middle of the electrode assembly can be 3% to 8%, preferably 4% to 8%.

[0198] The compressibility of the separator can be calculated by the difference between the thickness of the separator as supplied (fabric thickness before the process) and the thickness of the separator after electrode assembly is complete (after the process).

[0199] In an exemplary embodiment of the present invention, the thickness of the diaphragm located in the middle of the electrode assembly can be 1 to 1.09 times the thickness of the diaphragm located at the outermost side of the electrode assembly, preferably greater than 1 times and equal to or less than 1.09 times, more preferably greater than 1 times and equal to or less than 1.05 times, and most preferably greater than 1 times and equal to or less than 1.03 times.

[0200] That is, in an exemplary embodiment of the present invention, in an electrode assembly, the thickness of a diaphragm located at the outermost side of the electrode assembly may be less than the thickness of a diaphragm located in the middle of the electrode assembly, and the thickness of a diaphragm located in the middle of the electrode assembly may be equal to or less than 1.09 times the thickness of a diaphragm located at the outermost side of the electrode assembly.

[0201] In an exemplary embodiment of the present invention, the thickness deviation of the separator of the electrode assembly may be 9% or less, preferably 5% or less, and more preferably 3% or less.

[0202] The electrode assembly according to the present invention is manufactured by heating and pressing a stack (unfinished electrode assembly) in which electrodes and separators are stacked. Here, since the thickness deviation between the outermost separator of the electrode assembly and the middle separator of the electrode assembly is the largest, it is possible to check whether the thickness deviation of the separator of the electrode assembly is within the numerical range by comparing the thickness of the outermost separator of the electrode assembly and the middle separator of the electrode assembly.

[0203] An exemplary embodiment of the present invention provides an electrode assembly including a first electrode, a separator, and a second electrode, wherein the electrode assembly is stacked in a zigzag form, and after the zigzag stacking, the electrode assembly is heated and pressed to provide an electrode assembly satisfying Formula 1 below.

[0204] [Formula 1]

[0205] 1.02E A ≤E B

[0206] In formula 1,

[0207] E A is the energy density of the electrode assembly before heating and pressing (Wh / L), and

[0208] E B is the energy density (Wh / L) of the electrode assembly after heating and pressing.

[0209] In an exemplary embodiment of the present invention, the electrode assembly may satisfy the following Formula 1. Specifically, Formula 1 may be 1.02E A ≤E B , preferably 1.03E A ≤E B That is, the energy density (Wh / L) increases as the separator and electrodes are compressed during heating and pressing. In this case, energy density means power per unit volume.

[0210] The energy density is a value calculated by disassembling the electrode assembly, obtaining the energy densities at the outermost position and the middle position of the electrode assembly, and then averaging the values.

[0211] Therefore, the electrode assembly according to the exemplary embodiment of the present application has uniform performance and better withstand voltage because the thickness of the separator is uniform.

[0212] In an exemplary embodiment of the present invention, a compression rate of a separator located at the outermost side of the electrode assembly may be greater than a compression rate of a separator located in the middle of the electrode assembly.

[0213] That is, the electrode assembly according to the present invention has uniform performance and better withstand voltage because the thickness of the separator is uniform.

[0214] In an exemplary embodiment of the present invention, the withstand voltage of the electrode assembly may be 1.5 kV or higher.

[0215] Furthermore, the description of the electrode assembly manufacturing apparatus and the configuration of the manufacturing apparatus according to the present invention 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.

[0216] In an exemplary embodiment of the present invention, the air permeability of the separator located in the middle of the electrode assembly may be 80 sec / 100 ml to 120 sec / 100 ml, preferably 80 sec / 100 ml to 110 sec / 100 ml, and more preferably 85 sec / 100 ml to 100 sec / 100 ml.

[0217] Furthermore, in an exemplary embodiment of the present invention, the air permeability of the separator located at the outermost side of the electrode assembly may be 80 sec / 100 ml to 120 sec / 100 ml, preferably 80 sec / 100 ml to 110 sec / 100 ml, and more preferably 85 sec / 100 ml to 100 sec / 100 ml.

[0218] According to an exemplary embodiment of the present invention, the deviation between the air permeability of the separator located in the middle of the electrode assembly and the air permeability of the separator located at the outermost side 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.

[0219] [Mode for use in the present invention]

[0220] Although the exemplary embodiments of the present invention have been described in detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited thereto and that various modifications and changes may be made without departing from the technical spirit of the present invention defined in the claims.

[0221] <Manufacturing of Electrode Assembly>

[0222] 1) Example 1

[0223] 19 (nineteen) positive electrodes, 20 (twenty) negative electrodes, and separators are supplied to the stacking stage from the positive electrode supply unit, the negative electrode supply unit, and the separator supply unit, respectively.

[0224] More specifically, the positive electrode and the negative electrode are supplied in the form of being cut from the positive electrode sheet and the negative electrode sheet, respectively, and the separator is supplied in the form of a separator sheet. In this case, the positive electrode and the negative electrode are each manufactured to have a positive electrode joint and a negative electrode joint, respectively. Thereafter, the supplied separator is folded while the stacking table is rotated, and the positive electrode, the negative electrode, and the separator are stacked.

[0225] In this case, the positive electrode and the negative electrode are each supplied using an electrode stacking unit including an adsorption head, an electrode non-contact heater, and a moving unit.

[0226] In addition, stacking of the positive electrode or negative electrode stacked on the uppermost side of the stacking stage is performed using a holding mechanism. As a result, a stack (electrode assembly) in which the positive electrode, the negative electrode, and the separator are stacked in a zigzag form is manufactured.

[0227] Subsequently, the stack was inductively heated for 15 seconds using an induction heating unit including a U-shaped induction heating coil (induction heating process). Thereafter, the stack was allowed to wait for 15 seconds (waiting process). After the waiting process, the electrode joints of the stack were inductively heated for 15 seconds using an electrode joint induction heating unit including a U-shaped induction heating coil (electrode joint induction heating process). Subsequently, the electrode assembly of Example 1 was manufactured by heating and pressing the stack for 15 seconds under a temperature condition of 70° C. and a pressure condition of 3.5 MPa (heating and pressing process).

[0228] During the manufacturing process, the surface temperature variation of the stack S was measured. Specifically, a heated portion heated by the U-shaped induction heating coil and an unheated portion not heated by the U-shaped induction heating coil were distinguished from the surface of the stack S, and the temperature variation was measured for each portion. Fig. 9 Shown in.

[0229] In the process of manufacturing an electrode assembly, the above description of the present invention may be applied.

[0230] Subsequently, the adhesion mode of the electrode assembly of Example 1 was measured using an adhesion meter, and the results were Fig. 9 Specifically, along Fig. 9 The adhesion pattern of the electrode assembly is measured in the direction of the arrow.

[0231] according to Fig. 9 As a result, it can be confirmed that the surface temperature of the stack can be increased when the induction heating process is performed. In particular, it can be confirmed that since the induction heating can be performed on the electrodes that are not directly in contact and are not located at the outermost side of the stack, it can be prevented that the temperature is uneven between the electrodes during the heating and pressing process.

[0232] In addition, according to Fig. 9 As a result, it can be confirmed that when the waiting process is performed, the temperature deviation between the heated part and the unheated part can also be reduced. It can be confirmed that the bonding force pattern of the electrode assembly is uniform due to the reduced temperature deviation, such as Fig.10 shown.

[0233] In addition, it was confirmed that the electrode joint portion was also uniformly bonded by induction heating of the electrode joint portion.

[0234] 2) Comparative Example 1

[0235] The electrode assembly of Comparative Example 1 was manufactured in the same manner as in Example 1, except that the induction heating, electrode tap induction heating, and waiting processes in Example 1 were not performed.

[0236] <Experimental Example 1-Evaluation of Thickness Change of Diaphragm Fabric and Compressibility of Diaphragm>

[0237] For the electrode assemblies of Example 1 and Comparative Example 1, thickness variation of the separator fabric and compressibility of the separator were evaluated.

[0238] Specifically, after measuring the thickness of the diaphragm fabric before stacking, the electrode assemblies of Example 1 and Comparative Example 1 were disassembled. The diaphragm located at the top (outermost side) of the electrode assembly based on the stacking direction of the electrode assembly and the diaphragm corresponding to the middle position (central part) between the upper end and the lower end of the electrode assembly were collected, and the thickness change of the diaphragm fabric before and after the process was measured, and the results are shown in Table 1 below. In addition, the compression rate of the diaphragm was also calculated from the thickness change of the diaphragm fabric and is shown in Table 1 below.

[0239] [Table 1]

[0240]

[0241] As can be seen from Table 1, it can be confirmed that when the induction heating and waiting process are not performed, the variation deviation of the fabric thickness of the separator is large, and the fabric thickness of the separator at the outermost side is reduced more than necessary, and the fabric thickness of the separator at the central portion is almost unchanged. That is, in Comparative Example 1, unlike Example 1, it can be confirmed that the thickness deviation of the separator is large depending on the position of the electrode assembly.

[0242] This means that it is difficult for the electrode assembly to have uniform performance regardless of the position in the electrode assembly. That is, it can be confirmed that the electrode assembly manufactured by the manufacturing apparatus and method according to the present invention has uniform performance.

[0243] <Experimental Example 2-Evaluation of Withstand Voltage>

[0244] The withstand voltage was evaluated for the electrode assemblies of Example 1 and Comparative Example 1. The results are shown in Table 2 below.

[0245] [Table 2]

[0246] Withstand voltage(kV) Example 1 1.58 Comparative Example 1 1.17

[0247] As can be seen from Table 2, it can be confirmed that when the induction heating and waiting process is performed, the withstand voltage is worse than when the induction heating and waiting process is not performed. That is, in Comparative Example 1, it can be confirmed that the withstand voltage performance is not as good as that of Example 1.

[0248] <Experimental Example 3-Evaluation of Air Permeability of Separator>

[0249] After disassembling the electrode assemblies of Example 1 and Comparative Example 1, the separators corresponding to the middle positions of the upper and lower ends of the electrode assemblies based on the stacking direction of the electrode assemblies were collected, and the separators were each cut to prepare a separator sample having a size of 5 cm×5 cm (length×width). Thereafter, the separator sample was washed with an organic solvent.

[0250] Then, according to the JIS Gurley measurement method of the Japanese Industrial Standard, using a Gurley type air permeability tester (No. 158) available from Toyoseiki Co., Ltd., the air permeability of Example 1 and Comparative Example 1 was measured by measuring the time it takes for 100 ml (or 100 cc) of air to pass through a 1 square inch diaphragm at room temperature and a pressure of 0.05 MPa.

[0251] The results are shown in Table 3 below.

[0252] [Table 3]

[0253] Apply induction heating (waiting process) Air permeability of diaphragm (seconds / 100ml) Example 1 O 97 Comparative Example 1 X 98

[0254] As can be seen from Table 3, it can be confirmed that Example 1 and Comparative Example 1 have similar air permeability.

[0255] From the above experimental examples, it can be confirmed that the electrode assembly manufactured by the electrode assembly manufacturing apparatus and method of the present invention is excellent in the stability of the electrode and the separator, and has an appropriate level of air permeability at which deformation of the separator does not occur.

[0256] Furthermore, it was confirmed that an electrode assembly having excellent withstand voltage and uniform performance could be manufactured.

[0257] <Description of Reference Numerals and Symbols>

[0258] 10: Electrode assembly

[0259] 10a: First electrode connector

[0260] 11: First electrode

[0261] 12: Second electrode

[0262] 14: Diaphragm

[0263] 50: First heating and pressing unit

[0264] 50a, 50b: a pair of first pressing blocks

[0265] 51: Gripper

[0266] 51a: Main body

[0267] 51b: Fixed part

[0268] 60: Second heating and pressing unit

[0269] 60a, 60b: a pair of second pressing blocks

[0270] 100: Electrode assembly manufacturing device

[0271] 110: Stacking table

[0272] 111: Main body

[0273] 112: Stacking table heater

[0274] 120: Diaphragm supply unit

[0275] 121: Diaphragm heating unit

[0276] 122: Diaphragm roller

[0277] 130: First electrode supply unit

[0278] 131: First electrode placement platform

[0279] 133: First electrode roller

[0280] 134: First Cutter

[0281] 135: First conveyor belt

[0282] 136: First electrode supply head

[0283] 140: Second electrode supply unit

[0284] 141: Second electrode placement platform

[0285] 143: Second electrode roller

[0286] 144: Second Cutter

[0287] 145: Second conveyor belt

[0288] 146: Second electrode supply head

[0289] 150: first electrode stacking unit

[0290] 151: First adsorption head

[0291] 152: First head heater

[0292] 153: First mobile unit

[0293] 160: Second electrode stack unit

[0294] 161: Second suction head

[0295] 162: Second head heater

[0296] 163: Second mobile unit

[0297] 170: Maintaining the institution

[0298] 171: First holding mechanism

[0299] 172: Second holding mechanism

[0300] 180: Heating and pressing unit

[0301] 181: First block

[0302] 182: Second pressing block

[0303] 190: Induction heating unit

[0304] 191 (191a, 191b): Induction heating coil

[0305] 192 (192a, 192b): Induction heating plate

[0306] S: Stacked pieces

Claims

1. A method for manufacturing an electrode assembly, the electrode assembly comprising a first electrode, a separator and a second electrode, the method comprising the following steps: performing stacking by stacking a stack including the first electrode, the separator, and the second electrode on a stacking stage; performing induction heating by inductively heating the stack; as well as heating and pressing the induction heated stack, wherein at least one of the first electrodes of the stack comprises a first electrode contact, wherein at least one of the second electrodes of the stack comprises a second electrode contact, and The method further comprises the following step: performing electrode joint induction heating by induction heating at least one of the first electrode joint and the second electrode joint between the induction heating step and the heating and pressing step.

2. The method according to claim 1, wherein: In the electrode tab induction heating, at least one of the first electrode tab and the second electrode tab is induction heated using an induction heating coil.

3. The method according to claim 2, wherein: The induction heating coil is in contact with or spaced apart from the at least one of the first electrode tap and the second electrode tap by a predetermined distance.

4. The method according to claim 3, wherein: The predetermined distance is 15 mm or less.

5. The method according to claim 1, wherein: The electrode joint induction heating is performed for 1 second to 60 seconds.

6. The method according to claim 1, wherein: In the induction heating step, the stack is induction heated using an induction heating coil.

7. The method according to claim 1, wherein: The induction heating step includes, between the stacking step and the heating and pressing step, clamping the stack using a clamp including an induction heating coil and conveying the stack, and wherein the stack is inductively heated by the gripper during transport.

8. The method according to claim 1, wherein: The induction heating step includes transferring the stack to an induction heating device including an induction heating coil between the stacking step and the heating and pressing step, and Wherein, the induction heating step is performed in the induction heating device.

9. The method according to claim 8, wherein: The step of transferring the stack to the induction heating device including the induction heating coil is a step of holding the stack with a clamp and moving the stack to the induction heating device, and the induction heating step is a method for manufacturing an electrode assembly in which the stack is induction heated while being clamped by the clamp.

10. The method according to claim 1, further comprising the steps of: Between the induction heating step and the heating and pressing step, the stack is left to wait for a certain period of time in an atmospheric state.

11. The method according to claim 8, wherein: The waiting step is performed for 3 seconds or longer and 60 seconds or shorter.

12. An electrode assembly manufacturing device for manufacturing an electrode assembly, the electrode assembly comprising a first electrode, a separator and a second electrode, the electrode assembly manufacturing device comprising: a stacking stage on which the first electrode, the separator, and the second electrode are stacked so that a stack including the first electrode, the separator, and the second electrode is placed; as well as a heating and pressing unit configured to heat and press the stack, wherein at least one of the first electrodes of the stack comprises a first electrode contact, wherein at least one of the second electrodes of the stack comprises a second electrode contact, and Wherein, the electrode assembly manufacturing equipment also includes: an induction heating unit configured to inductively heat the stack while transferring the stack from the stacking stage to the heating and pressing unit, and An electrode tab induction heating unit is configured to induction heat at least one of the first electrode tab and the second electrode tab before heating and pressing the stack that has been induction heated in the induction heating unit in the heating and pressing unit.

13. The electrode assembly manufacturing equipment according to claim 12, wherein: The induction heating unit is a clamper including an induction heating coil, and is configured to clamp the stack so as to transfer the stack to the heating and pressing unit.

14. The electrode assembly manufacturing equipment according to claim 12, wherein: The induction heating unit comprises: a first induction heating device, the first induction heating device comprising an induction heating coil; and A first device moving unit configured to move the first induction heating device to a surface of the stack.

15. The electrode assembly manufacturing equipment according to claim 12, wherein: The clamper is also included between the stacking table and the induction heating unit for holding and moving the stack, and The induction heating unit is an electrode assembly manufacturing device that inductively heats the stack while the stack is clamped by the clamper.

16. The electrode assembly manufacturing equipment according to claim 12 further includes a first control unit, which is configured to measure the temperature distribution on the surface of the stack, set the induction heating temperature for the stack according to the measured temperature distribution, and determine whether to stop the induction heating of the stack based on the induction heating temperature and induction heating time for the stack.

17. The electrode assembly manufacturing apparatus according to claim 12, wherein: The electrode joint induction heating unit comprises: a second induction heating device, the second induction heating device comprising an induction heating coil, and A second device moving unit configured to move the second induction heating device to the first electrode joint portion or the second electrode joint portion.

18. The electrode assembly manufacturing apparatus according to claim 17, wherein: The induction heating coil is in contact with or spaced apart from the at least one of the first electrode tap and the second electrode tap 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 comprising a first electrode, a separator and a second electrode, in, The electrode assemblies are stacked in a zigzag pattern, wherein the diaphragms are compressed after being stacked in a zigzag manner, and The compression rate of the separator located at the outermost side of the electrode assembly is greater than the compression rate of the separator located in the middle of the electrode assembly, and the difference in compression rate is 3%p or less.

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

22. The electrode assembly according to claim 20, wherein: The separator located in the middle of the electrode assembly has an air permeability of 80 sec / 100 ml to 120 sec / 100 ml.

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