Electrode assembly and method for manufacturing the electrode assembly

Abstract

The present invention is directed to providing an electrode assembly and a method for manufacturing the electrode assembly.

Description

[Technical Field]

[0001] The present invention claims the benefit of the filing date of Korean Patent Application No. 10-2022-0174039, filed with the Korean Intellectual Property Office on December 13, 2022, the entire contents of which are incorporated herein by reference. The present invention relates to an electrode assembly and a method for manufacturing the electrode assembly. [Background technology]

[0002] Unlike primary batteries, secondary batteries are rechargeable and have the potential to be small and have large capacities. As technological development and demand for mobile devices increases, the demand for secondary batteries as an energy source is rapidly increasing.

[0003] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries depending on the shape of the battery case. The electrode assembly installed inside the battery case of a secondary battery is a power generating element that can be charged and discharged and is made up of a laminated structure of electrodes and a separator.

[0004] Electrode assemblies can be broadly classified into a jelly-roll type in which a sheet-like positive electrode and negative electrode coated with an active material are wound up with a separator interposed between them, a stack type in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them, and a stack-and-fold type in which stack-type unit cells are wound up with a long separator film.

[0005] Here, in the zigzag folding type electrode assembly, a separator is folded in a zigzag pattern and electrodes are positioned between the separators, and the electrode assembly is fabricated using a plurality of electrodes.

[0006] During this process, when the separator is fed to the stack table, wrinkles or misalignment may occur in the separator, resulting in defective electrode assemblies or reduced performance.

[0007] Therefore, there is a need for process conditions or methods for eliminating the occurrence of wrinkles or misalignment defects in the separator provided during the manufacturing process of the electrode assembly. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides an electrode assembly and an apparatus for manufacturing the electrode assembly. [Means for solving the problem]

[0009] One embodiment of the present invention provides a method for manufacturing an electrode assembly in which first and second electrodes are alternately arranged between folded separators, the method comprising: supplying the first electrodes to a stack table; supplying the second electrodes to a stack table; supplying the separator to the stack table; and stacking a stack on the stack table in which the first and second electrodes are alternately arranged between the folded separators, wherein the step of supplying the separator to the stack table includes simultaneously performing a step of coating one side of the separator with an aqueous binder and a step of coating the other side of the separator with an organic binder; and supplying the separator coated with different binders on both sides.

[0010] Another embodiment of the present invention provides an electrode assembly in which first and second electrodes are alternately arranged between folded separators, wherein both sides of the separator are coated with different binders, one side of the separator includes an aqueous binder coating layer and the other side of the separator includes an organic binder coating layer, the first electrode has a side coated with the aqueous binder and the second electrode has a side coated with the organic binder, the aqueous binder coating layer of the separator contacts the first electrode and the organic binder coating layer of the separator contacts the second electrode. [Effects of the Invention]

[0011] The method for manufacturing an electrode assembly according to the embodiments of the present application can increase the efficiency of the process. The method for manufacturing an electrode assembly according to an embodiment of the present disclosure can increase the adhesive strength between the electrodes and the separator of the manufactured electrode assembly, and therefore the electrode assembly manufactured by the method for manufacturing an electrode assembly according to an embodiment of the present disclosure has excellent performance.

[0012] The method for manufacturing an electrode assembly according to an embodiment of the present application can provide an electrode assembly with uniform and excellent performance. [Brief explanation of the drawings]

[0013] [Figure 1] 1A to 1C are diagrams illustrating a method for manufacturing an electrode assembly according to an embodiment of the present invention. [Figure 2] 1 is a plan view illustrating an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention; [Figure 3] 1 is a front view showing the concept of an electrode assembly manufacturing apparatus according to an embodiment of the present invention; [Figure 4] 1 is a cross-sectional view illustrating an electrode assembly manufactured by an electrode assembly manufacturing apparatus according to an embodiment of the present invention; [Figure 5]3 is a perspective view illustrating a press unit and a state in which the press unit presses a laminate in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention; FIG. [Figure 6] 1(a) is a perspective view showing a first press section 50 according to one embodiment of the present invention, and FIG. 1(b) is a perspective view showing a second press section 60 according to one embodiment of the present invention. [Figure 7] 1 is a perspective view showing a stack table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention; [Figure 8] 1 is a perspective view showing a first electrode seating table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention; [Figure 9] 3 is a perspective view showing a second electrode seating table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention. FIG. [Figure 10] 1 is a perspective view showing a first suction head of an electrode assembly manufacturing apparatus according to an embodiment of the present invention. [Figure 11] 1 is a bottom view showing a first suction head of an electrode assembly manufacturing apparatus according to an embodiment of the present invention. [Figure 12] 1 is a plan view showing a holding mechanism and a stack table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0015] In this specification, when a part is said to "comprise" a certain component, this does not mean that it may further include other components, unless specifically stated to the contrary, but rather that it does not exclude other components.

[0016] In this specification, "p to q" means "not less than p and not more than q." In this specification, the term "organic binder coating layer" or "organic binder layer" refers to a layer formed by coating with an organic binder, and the term "aqueous binder coating layer" or "aqueous binder layer" refers to a layer formed by coating with an aqueous binder.

[0017] In describing the present invention, detailed descriptions of related art that may obscure the gist of the present invention will be omitted.

[0018] One embodiment of the present invention provides a method for manufacturing an electrode assembly in which first and second electrodes are alternately arranged between folded separators, the method comprising: supplying the first electrodes to a stack table; supplying the second electrodes to a stack table; supplying the separator to the stack table; and stacking a stack on the stack table in which the first and second electrodes are alternately arranged between the folded separators, wherein the step of supplying the separator to the stack table includes simultaneously performing a step of coating one side of the separator with an aqueous binder and a step of coating the other side of the separator with an organic binder; and supplying the separator coated with different binders on both sides.

[0019] In this specification, the state in which the first electrode and the second electrode are alternately stacked between the folded separator is referred to as zigzag folding.

[0020] The method for manufacturing an electrode assembly according to the present invention is characterized by simultaneously coating one side of the separator with an aqueous binder and the other side of the separator with an organic binder. By simultaneously performing these two different coatings, process efficiency can be improved. Furthermore, by coating both sides of the separator with an aqueous binder and an organic binder, respectively, the adhesive strength between the separator and the first and second electrodes can be strengthened. This allows for the provision of an electrode assembly with uniform and excellent performance.

[0021] In one embodiment of the present invention, the step of simultaneously coating one side of the separation membrane with an aqueous binder and coating the other side of the separation membrane with an organic binder may include: preparing a coating liquid containing the organic binder and the aqueous binder; phase-separating the coating liquid to form an interface between the organic binder and the aqueous binder; and simultaneously coating both sides of the separation membrane while moving the separation membrane through the interface.

[0022] In one embodiment of the present invention, the coating liquid may contain the aqueous binder in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the coating liquid, and the organic binder in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the coating liquid.

[0023] In one embodiment of the present invention, the coating liquid may contain the aqueous binder in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably 1 to 12 parts by weight, based on 100 parts by weight of the coating liquid.

[0024] In one embodiment of the present invention, the coating liquid may contain the organic binder in an amount of 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight, and more preferably 5 to 15 parts by weight, based on 100 parts by weight of the coating liquid.

[0025] When the content of the coating liquid is satisfied, the adhesive strength between the electrode and the separator can be improved, and the problem of a decrease in ion conductivity and a decrease in battery performance can be prevented.

[0026] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include coating one surface of the separator with an aqueous binder and coating the other surface of the separator with an organic binder, and then drying the coating.

[0027] In one embodiment of the present invention, the step of drying the coating may be carried out at a temperature of 50°C to 70°C, preferably 55°C to 65°C.

[0028] FIG. 1 schematically illustrates a method for manufacturing an electrode assembly according to the present invention. Referring to FIGS. 1 and 2, as a separator 14 is supplied from a separator supply unit 120, the separator 14 passes through a coating solution A, as shown in FIG. 1. More specifically, the coating solution A includes an organic binder and an aqueous binder. The organic binder and the aqueous binder in the coating solution A undergo phase separation, and the organic binder solution C and the aqueous binder solution D form an interface B between the solutions. At this time, the separator 14 passes through the interface B between the organic binder and the aqueous binder. The length of the travel distance may be determined based on the size of the electrode assembly to be manufactured, and the separator may be traveled by a number of travel rollers 1, 2, 3, 4, and 5.

[0029] The separator 14 that has passed through interface B between the organic binder and the aqueous binder is dried at a certain temperature, forming an organic binder layer and an aqueous binder layer on both sides of the separator 14. Unlike existing methods, the method for manufacturing an electrode assembly according to the present invention can simultaneously coat both sides of the separator 14 with two different binders by passing through interface B between the organic binder and the aqueous binder, thereby achieving the above-mentioned effects.

[0030] In one embodiment of the present invention, the water-based binder may be one or more selected from the group consisting of water-based acrylic copolymers, styrene-sodium carboxymethyl cellulose (CMC), polyacrylic acid copolymers, polyacrylamide copolymers, styrene-butadiene rubber (SBR), water-dispersible urethane copolymers, and urea copolymers.

[0031] In one embodiment of the present invention, the organic binder may be one or more selected from the group consisting of polyvinylidene fluoride (PVDF) copolymers, organic acrylic copolymers, urethane copolymers, polyamide copolymers, polyimide copolymers, and polyacrylonitrile copolymers.

[0032] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include coating one of the first electrode and the second electrode with a coating liquid including the aqueous binder and coating the other electrode with a coating liquid including the organic binder, wherein one side of the separator coated with the aqueous binder may be in contact with a side of the electrode coated with the aqueous binder, and the other side of the separator coated with the organic binder may be in contact with a side of the electrode coated with the organic binder.

[0033] More specifically, in one embodiment of the present invention, the electrode coated with the aqueous binder may be a negative electrode, and the electrode coated with the organic binder may be a positive electrode.

[0034] That is, in order to strengthen the adhesive strength between the electrode and the separator, it is preferable to use the same type of binder for coating the positive electrode and the binder contained in the coating layer formed on the surface of the separator facing the positive electrode, and the same applies to the negative electrode.

[0035] Generally, an organic binder is used for the positive electrode and an aqueous binder is used for the negative electrode, so by contacting the binder layer on the corresponding separator surface, the adhesive strength between the separator and the electrode can be further improved.

[0036] Generally, aqueous binders have excellent adhesive strength with anodes (graphite-based or silicon-based) that use aqueous slurries, while organic binders have excellent adhesive strength with cathodes that use organic slurries. Therefore, when a separator using an organic binder is used, the adhesive strength with the anode decreases, the gap between the anode and the separator increases, and this increases the likelihood of precipitation occurring at the top of the cell.

[0037] Therefore, by using an organic binder on the positive electrode adhesive surface of the separator and an aqueous binder on the negative electrode adhesive surface, the adhesive strength between the positive electrode, separator, and negative electrode can be improved, and precipitation of the cell can be prevented.

[0038] In one embodiment of the present invention, the step of stacking the stack on the stack table includes step S1 of stacking a separation membrane on the stack table; step S2 of stacking a first electrode on an upper surface of the separation membrane; step S3 of supplying a separation membrane while rotating the stack table to cover an upper surface of the first electrode; and step S4 of stacking the second electrode on the separation membrane covering the upper surface of the first electrode; and steps S1 to S4 may be repeated one or more times.

[0039] In one embodiment of the present invention, the method may further include a step of holding the first electrode or the second electrode using a holding mechanism and fixing it to the stack table when the first electrode or the second electrode is stacked on the stack table.

[0040] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include heating and pressurizing the stacked structure on the stack table.

[0041] In one embodiment of the present invention, the step of heating and pressing the laminate may include the steps of: moving the laminate between a pair of pressurizing blocks, and applying surface pressure to the laminate while the pair of pressurizing blocks move toward the laminate in opposing directions; and heating the laminate with a press heater. The press heater may be included inside the pressurizing blocks.

[0042] In one embodiment of the present invention, the step of heating and pressing the laminate may be performed under conditions of a temperature of 55°C or more and 70°C or less, a pressure of 1.5 MPa or more and 3 MPa or less, and a time of 5 seconds or more and 20 seconds or less.

[0043] Here, the pressure condition refers to the pressure applied by the pair of pressure blocks (or the pressure block applied to the stack table), and the temperature condition refers to the temperature of the heat applied by the press heater.

[0044] One embodiment of the present invention provides an electrode assembly apparatus for manufacturing an electrode assembly by stacking a first electrode, a separator, and a second electrode, the apparatus including: a stack table on which the first electrode, the separator, and the second electrode are stacked such that the first electrode and the second electrode are alternately arranged between folded separators; a separation membrane supply unit that supplies the separation membrane to the stack table; a first electrode supply unit that supplies the first electrode; a second electrode supply unit that supplies the second electrode; a first electrode stacking unit that stacks the first electrode supplied from the first electrode supply unit on the stack table; a second electrode stacking unit that stacks the second electrode supplied from the second electrode supply unit on the stack table; and a press unit that heats and pressurizes the stack of the first electrode, the separator, and the second electrode stacked on the stack table to bond the first electrode, the separator, and the second electrode together.

[0045] In this case, the separator supply unit simultaneously coats one surface of the separator with an aqueous binder and the other surface of the separator with an organic binder, as in the above-described method for manufacturing an electrode assembly, and then supplies the separator to the stack table.

[0046] In an embodiment of the present invention, the separation membrane supply unit may include a separation membrane dancer unit for adjusting the tension of the separation membrane being supplied.

[0047] In one embodiment of the present invention, the stacking device may further include a holding mechanism that grips and fixes the first electrode or the second electrode on the stack table when the first electrode or the second electrode is stacked on the stack table.

[0048] In one embodiment of the present invention, the press section may further include a pair of pressure blocks and a press heater that heats the pressure blocks, and the pair of pressure blocks may move in opposing directions to apply surface pressure to the stacked laminate while heating it.

[0049] In one embodiment of the present invention, the press heater may be included inside the pressurizing block.

[0050] In one embodiment of the present invention, the press unit may heat and pressurize the laminate of the first electrode, the separation membrane, and the second electrode under temperature conditions of 55°C or higher and 70°C or lower, and pressure conditions of 1.5 MPa or higher and 3 MPa or lower for a time period of 5 seconds or higher and 20 seconds or lower, thereby bonding the first electrode, the separation membrane, and the second electrode together.

[0051] Here, the pressure condition refers to the pressure applied by the pair of pressure blocks (or the pressure block applied to the stack table), and the temperature condition refers to the temperature of the heat applied by the press heater.

[0052] In one embodiment of the present invention, the first electrode supply unit may include a first electrode seating table on which the first electrodes are seated before being stacked on the stack table by the first electrode stacking unit, and the second electrode supply unit may include a second electrode seating table on which the second electrodes are seated before being stacked on the stack table by the second electrode stacking unit.

[0053] In addition, in one embodiment of the present invention, the first electrode stack unit may include a first suction head that vacuum-sucks the first electrode seated on the first electrode seating table, and the second electrode stack unit may include a second suction head that vacuum-sucks the second electrode seated on the second electrode seating table.

[0054] In one embodiment of the present invention, the stacking device may further include a rotating unit that rotates the stack table, wherein a first electrode stacking unit is provided on one side of the rotating unit and a second electrode stacking unit is provided on the other side of the rotating unit so that the separator can be zigzag folded in a manner such that the separator is positioned between the first electrode and the second electrode, and the rotating unit may alternately rotate the stack table to one side to face the first suction head of the first electrode stack unit when stacking the first electrode, and rotate the stack table to the other side to face the second suction head of the second electrode stack unit when stacking the second electrode.

[0055] One embodiment of the present invention provides an electrode assembly in which first and second electrodes are alternately arranged between a folded separator, wherein both sides of the separator are coated with different binders, one side of the separator comprising an aqueous binder coating layer and the other side of the separator comprising an organic binder coating layer, the first electrode having a surface coated with the aqueous binder and the second electrode having a surface coated with the organic binder, the aqueous binder coating layer of the separator contacting the first electrode and the organic binder coating layer of the separator contacting the second electrode.

[0056] That is, in this specification, a description of an apparatus for manufacturing an electrode assembly can be applied to a method for manufacturing an electrode assembly and the electrode assembly itself, and vice versa.

[0057] The electrode assembly manufacturing apparatus and electrode assembly manufacturing method of the present invention will be described in more detail below with reference to FIGS.

[0058] Fig. 2 is a plan view illustrating an example of an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention, and Fig. 3 is a front view illustrating the concept of the apparatus for manufacturing an electrode assembly according to an embodiment of the present invention. For convenience, Fig. 2 omits the holding mechanism 170 and the pressing unit 180 shown in Fig. 3, and Fig. 3 omits the separation membrane supply unit 120 shown in Fig. 2.

[0059] In this specification, the term "holding mechanism" refers to a mechanism that grips the stacked material on the stack table in order to stack the first electrodes or the second electrodes during the process of manufacturing a stacked material in which the first electrodes, the separation film, and the second electrodes are stacked, in a form in which the first electrodes and the second electrodes are alternately arranged between the separation film folded on the stack table, and its function is different from that of a gripper that grips the stacked material during the process of applying heat and pressure.

[0060] 1 to 3, an apparatus 100 for manufacturing an electrode assembly according to an embodiment of the present invention includes a stack table 110, a separation membrane supply unit 120 for supplying a separation membrane 14, a first electrode supply unit 130 for supplying a first electrode 11, a second electrode supply unit 140 for supplying a second electrode 12, a first electrode stacking unit 150 for stacking the first electrode 11 on the stack table 110, a second electrode stacking unit 160 for stacking the second electrode 12 on the stack table 110, and a press unit 180 for bonding the first electrode 11, the separation membrane 14, and the second electrode 12 together. The apparatus 100 for manufacturing an electrode assembly according to an embodiment of the present invention may further include a holding mechanism 170 for fixing the first electrode 11 and the second electrode 12 when they are stacked on the stack table 110. The same description as for FIG. 1 applies to the separation membrane supplied from the separation membrane supply unit.

[0061] In one embodiment of the present invention, the first electrode, the separation membrane, and the second electrode may be supplied to the stack table while being heated.

[0062] That is, the separation membrane supply unit may supply the separation membrane to the stack table while heating it, and the first electrode supply unit and the second electrode supply unit may supply the first electrode and the second electrode to the stack table while heating the first electrode and the second electrode, respectively.

[0063] 4 is a cross-sectional view illustrating an example of an electrode assembly manufactured by an electrode assembly manufacturing apparatus or method according to an embodiment of the present invention. In this case, an organic binder layer and an aqueous binder layer are formed on both sides of the separator, respectively, and the above description can be applied to the electrodes in contact therewith.

[0064] 1 to 4, an apparatus 100 for manufacturing an electrode assembly according to an embodiment of the present invention is an apparatus for manufacturing an electrode assembly 10 by stacking a first electrode 11, a separator 14, and a second electrode 12.

[0065] As shown in FIG. 4, the electrode assembly 10 is generally a chargeable / dischargeable power generating element and may be formed by alternately stacking and assembling a first electrode 11, a separator 14, and a second electrode 12. Here, the electrode assembly 10 may be formed, for example, by folding the separator 14 in a zigzag pattern, with the first electrode 11 and the second electrode 12 alternately disposed between the folded separator 14. In this case, the electrode assembly 10 may be provided in a form in which the separator 14 encases the outermost shell. In this case, as described above, an organic binder layer and an aqueous binder layer are formed on both sides of the separator 14, respectively.

[0066] 2, the separation membrane supply unit 120 may further include a separation membrane roll 122 around which the separation membrane 14 is wound. The separation membrane wound on the separation membrane roll may be sequentially unwound and supplied to a stack table. That is, the separation membrane may be in the form of a separation membrane sheet. In this case, the separation membrane 14 may be heated by a separation membrane heating unit 121, and the tension of the separation membrane may be adjusted by the dancer unit (not shown) as described above.

[0067] 5, the pressing unit 180 may further include a pair of pressure blocks 181 and 182 and press heaters 183 and 184 disposed inside the pair of pressure blocks 181 and 182. In this case, the pair of pressure blocks 181 and 182 may move in opposite directions to pressurize the laminate S and heat it using the press heaters 183 and 184. The heating and pressing conditions may be the same as those described above.

[0068] In one embodiment of the present application, the press unit may be divided into a first press unit and a second press unit. The first press unit heats and presses the laminate while gripping the laminate with grippers, and the second press unit may be used to secondarily heat and press the laminate, which has been primarily heated and pressurized by the first press unit, without gripping it with grippers. In this case, the heating and pressurizing conditions of the first press unit and the second press unit may be the same as those of the press unit described above.

[0069] In this regard, FIG. 6(a) is a perspective view showing a first press unit 50 according to one embodiment of the present invention, and FIG. 6(b) is a perspective view showing a second press unit 60 according to one embodiment of the present invention.

[0070] 6(a), the first press unit 50 can apply heat and pressure to the laminate S while it is fixed by the gripper 51. The first press unit 50 is composed of a pair of first pressure blocks 50a and 50b, and the pair of first pressure blocks 50a and 50b have flat pressure surfaces except for a groove corresponding to the fixing portion 51b of the gripper 51.

[0071] The gripper 51 may include a main body 51a that corresponds to the length x and height y of the stack S or is wider than the length x and height y of the stack S, and a plurality of fixing portions 51b provided on one surface of the main body 51a and having a pillar or plate shape along the width z direction of the stack S. Here, the length x of the stack S may refer to the longest part from one end to the other end of the stack S, the height y may refer to the distance in the stacking direction of the stack S, and the width z may refer to the distance across the top surface of the stack S.

[0072] The position of the fixing part 51b can be adjusted along the height direction of the main body 51a, and the fixing part 51b can contact the upper and lower surfaces of the laminate S to fix the laminate S. Thereafter, a pair of first pressure blocks 50a and 50b included in the first press part 50 can apply surface pressure to one or more of the laminate S and the gripper 51 while moving in opposite directions, thereby bonding the electrodes and the separator included in the laminate S.

[0073] 6(b), the second press unit 60 may finally heat and press the laminate S that has been primarily heated and pressed by the first press unit 50. The second press unit 60 includes a pair of second press blocks 60a and 60b, which may move in opposite directions to apply surface pressure to the laminate S. In addition, the pair of second press blocks 60a and 60b included in the second press unit 60 may all have flat pressure surfaces that come into contact with and press the laminate S.

[0074] FIG. 7 is a perspective view showing a stack table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention.

[0075] Referring to Figures 3 and 7, the stack table 110 may have first electrodes 11, separators 14, and second electrodes 12 stacked in a manner such that the first electrodes 11 and the second electrodes 12 are alternately arranged between the folded separators 14.

[0076] The stack table 110 may also include a table body 111 on which the first electrode 11, the separation membrane 14, and the second electrode 12 are stacked, and a stack table heater 112 that heats the table body 111 to heat the stacked stack S.

[0077] The first electrode 11 may be a positive electrode and the second electrode 12 may be a negative electrode, but the present invention is not necessarily limited to this. For example, the first electrode 11 may be a negative electrode and the second electrode 12 may be a positive electrode.

[0078] FIG. 8 is a perspective view showing a first electrode seating table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention.

[0079] 3 and 8, the first electrode supply unit 130 may supply the first electrode 11 to the first electrode stack unit 150 while heating the first electrode 11.

[0080] In addition, the first electrode supply unit 130 may include a first electrode seating table 131 on which the first electrode 11 is seated before being stacked on the stack table 110 by the first electrode stack unit 150, and a first electrode heater 132 that heats the first electrode seating table 131 and thereby heats the first electrode 11.

[0081] Meanwhile, the first electrode supply unit 130 may further include a first electrode roll 133 on which the first electrode 11 is wound in sheet form, a first cutter 134 that cuts the sheet-like first electrode 11 wound around the first electrode roll 133 at regular intervals as it is unwound and supplied to form first electrodes 11 of a predetermined size, a first conveyor belt 135 that moves the first electrodes 11 cut by the first cutter 134, and a first electrode supply head 136 that vacuum-sucks the first electrodes 11 transported by the first conveyor belt 135 and seats them on the first electrode seating table 131. Here, the first cutter 134 may cut the sheet-like first electrodes 11 so that first electrode tabs 11a protrude from the ends of the first electrodes 11 when cutting them.

[0082] FIG. 9 is a perspective view showing a second electrode seating table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention.

[0083] 3 and 9, the second electrode supply unit 140 may supply the second electrode 12 to the second electrode stack unit 160 while heating the second electrode 12.

[0084] The second electrode supply unit 140 may also include a second electrode seating table 141 on which the second electrode 12 is seated before being stacked on the stack table 110 by the second electrode stack unit 160, and a second electrode heater 142 that heats the second electrode seating table 141 and thereby heats the second electrode 12.

[0085] Meanwhile, the second electrode supply unit 140 may further include a second electrode roll 143 on which the second electrode 12 is wound in sheet form, a second cutter 144 that cuts the sheet-like second electrode 12 wound around the second electrode roll 143 at regular intervals as it is unwound and supplied to form second electrodes 12 of a predetermined size, a second conveyor belt 145 that moves the second electrodes 12 cut by the second cutter 144, and a second electrode supply head 146 that vacuum-sucks the second electrodes 12 transported by the second conveyor belt 145 and seats them on the second electrode seating table 141. Here, the second cutter 144 may cut the sheet-like second electrodes 12 so that second electrode tabs 12a protrude from the ends of the second electrodes 12 when cutting them.

[0086] In one embodiment of the present invention, the first electrode stack unit may include a first suction head that vacuum-sucks the first electrode mounted on the first electrode mounting table, and the second electrode stack unit may include a second suction head that vacuum-sucks the second electrode mounted on the second electrode mounting table.

[0087] FIG. 10 is a perspective view showing a first suction head in an apparatus for manufacturing an electrode assembly according to one embodiment of the present invention, and FIG. 11 is a bottom view showing the first suction head in an apparatus for manufacturing an electrode assembly according to one embodiment of the present invention.

[0088] Referring to FIGS. 2, 3, 10, and 11, the first electrode stacking unit 150 can stack the first electrodes 11 on the stack table 110.

[0089] The first electrode stack unit 150 may include a first suction head 151 and a first moving unit 153.

[0090] The first suction head 151 can vacuum-suck the first electrode 11 seated on the first electrode seating table 131. In this case, the first suction head 151 has a vacuum suction port 151a formed on a bottom surface 151b thereof, and can suck the first electrode 11 through the vacuum suction port 151a to fix the first electrode 11 to the bottom surface 151b of the first suction head 151. Here, the first suction head 151 may have a passage formed therein that connects the vacuum suction port 151a to a vacuum suction device (not shown).

[0091] The first moving unit 153 can move the first suction head 151 to the stack table 110 so that the first suction head 151 can stack the first electrode 11 seated on the first electrode seating table 131 on the stack table 110.

[0092] The second electrode stacking unit 160 can stack the second electrodes 12 on the stack table 110. Here, the second electrode stacking unit 160 may have the same structure as the first electrode stacking unit 150. In this case, the second electrode stacking unit 160 may include a second suction head 161 and a second moving unit 163.

[0093] The second suction head 161 can vacuum-suck the second electrode 12 seated on the second electrode seating table 141 .

[0094] The second moving unit 163 can move the second suction head 161 to the stack table 110 so that the second suction head 161 can stack the second electrode 12 seated on the first electrode seating table 141 on the stack table 110.

[0095] FIG. 12 is a plan view showing a holding mechanism and a stack table in an apparatus for manufacturing an electrode assembly according to an embodiment of the present invention.

[0096] Referring to Figures 3 and 12, the holding mechanism 170 can grip the first electrode 11 or the second electrode 12 and fix it to the stack table 110 when the first electrode 11 or the second electrode 12 is stacked on the stack table 110.

[0097] In addition, when stacking the first electrode 11 on the stack table 110, the holding mechanism 170 may pressurize and fix the upper surface of the first electrode 11 stacked on the uppermost side of the stack table 110, and when stacking the second electrode 12 on the stack table 110, the holding mechanism 170 may pressurize and fix the upper surface of the second electrode 12 stacked on the uppermost side of the stack table 110. In addition, the holding mechanism 170 may pressurize and fix the upper surface of the stack of the first electrode 11, the separator 14, and the second electrode 12 stacked on the stack table 110.

[0098] That is, when the first electrode 11 and the second electrode 12 are arranged and stacked between the separation membranes 14 to form a stack, the holding mechanism 170 holds the uppermost surface of the stack by applying pressure toward the stack table 110, thereby preventing the stack from coming off the stack table 110.

[0099] Meanwhile, the holding mechanism 170 may include, for example, a first holding mechanism 171 and a second holding mechanism 172, and may fix both sides of the first electrode 11 or the second electrode 12.

[0100] Thereafter, the holding mechanism 170 holds the first electrode 11 or the second electrode 12, and then rotates the stack table 110, so that the separation membrane 14 can be unwound from the separation membrane roll 122 and supplied to the stack table 110 side.

[0101] Alternatively, stacking the first and second electrodes alternately between the folded separators may be performed by moving the stack table or separator left and right. In this case, after the holding mechanism 170 holds the first electrode 11 or the second electrode 12, the stack table 110 or separator 14 is moved left and right, and the separator 14 is unwound from the separator roll 122 and supplied to the stack table 110. Meanwhile, for example, the stack table 110 may be connected or coupled to a stack table moving unit (not shown) and moved left and right, and the separator may be supplied to the stack table while being moved left and right by a separation membrane guide unit (not shown).

[0102] In one embodiment of the present invention, the first electrode may be a positive electrode and the second electrode may be a negative electrode.

[0103] In one embodiment of the present invention, the first electrode may be a negative electrode and the second electrode may be a positive electrode.

[0104] In one embodiment of the present invention, the positive electrode may be prepared by coating a mixture of a positive electrode active material, a conductive material, and a binder on a positive electrode current collector and then drying the mixture, and if necessary, a filler may be further added to the mixture. In this case, materials commonly used in the relevant field may be used.

[0105] Specifically, the positive electrode active material is, for example, a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; 1+x Mn 2-x Lithium manganese oxides such as LiMnO4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiFe3O4, V2O5, and Cu2V2O7; and the chemical formula LiNi 1-x M xNi-site lithium nickel oxide represented by the chemical formula LiMn 2-x M x Examples of the lithium manganese composite oxides include, but are not limited to, lithium manganese composite oxides represented by Li2Mn3MO8 (wherein M is Co, Ni, Fe, Cr, Zn, or Ta, and x is 0.01 to 0.1) or Li2Mn3MO8 (wherein M is Fe, Co, Ni, Cu, or Zn); LiMn2O4 in which part of the Li in the chemical formula is substituted with an alkaline earth metal ion; disulfide compounds; and Fe2(MoO4)3.

[0106] Specifically, the positive electrode current collector is not particularly limited as long as it does not induce chemical changes in the battery and has high conductivity. For example, stainless steel, aluminum, nickel, titanium, baked carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. may be used, but in particular aluminum may be used. The positive electrode current collector may have fine irregularities on its surface to increase the adhesive strength of the positive electrode active material, and may be in various forms such as a film, sheet, foil, net, porous material, foam, or nonwoven fabric. The positive electrode current collector may generally have a thickness of 3 μm to 500 μm.

[0107] The conductive material may typically be added in an amount of 1 wt % to 50 wt % based on the total weight of the mixture containing the positive electrode active material. Such a conductive material is not particularly limited as long as it does not induce chemical changes in the battery and has conductivity, and examples thereof include graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0108] The binder is a component that aids in bonding the active material and conductive material and the current collector, and may typically be added in an amount of 1 to 50 wt % based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers.

[0109] The filler is selectively used as a component that suppresses expansion of the positive electrode, and is not particularly limited as long as it does not induce chemical changes in the battery and is a fibrous material. For example, olefin polymers such as polyethylene and polypropylene; glass fiber, carbon fiber, and other fibrous materials are used.

[0110] In one embodiment of the present invention, the negative electrode is prepared by applying the negative electrode active material to a negative electrode current collector, drying, and pressing the applied material, and may optionally further include a conductive material, a binder, a filler, etc., as described above. In this case, materials commonly used in the relevant field may be used.

[0111] Specifically, the negative electrode active material may be, for example, carbon such as graphitizable carbon and graphite-based carbon; LixFe2O3 (0 ≦ x ≦ 1), Li x WO2 (0 ≦ x ≦ 1), Sn x Me 1-x Me’ y metal composite oxides such as Oz (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials, etc. may be used.

[0112] Such a negative electrode current collector is not particularly limited as long as it does not induce a chemical change in the battery and has conductivity. For example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, those surface-treated with carbon, nickel, titanium, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloy, etc. may be used. Also, similar to the positive electrode current collector, fine irregularities can be formed on the surface to strengthen the binding force of the negative electrode active material, and it may be used in various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven fabrics, etc. Further, the negative electrode current collector may generally have a thickness of 3 μm to 500 μm.

[0113] In one embodiment of the present invention, the separator may be an organic / inorganic composite porous SRS (Safety-Reinforcing Separators) separator. The SRS separator may have a structure in which a coating layer component containing inorganic particles and a binder polymer is applied on a polyolefin-based separator substrate.

[0114] The SRS separator does not undergo high-temperature thermal shrinkage due to the heat resistance of the inorganic particles, and can maintain its elongation even when the electrode assembly is pierced by the needle-shaped conductor.

[0115] Such an SRS separator may have a uniform pore structure formed by the pore structure contained in the separator substrate itself and the interstitial volume between the inorganic particles, which are components of the coating layer. The pores not only mitigate external impacts on the electrode assembly, but also allow smooth movement of lithium ions through the pores, allowing a large amount of electrolyte to be filled, resulting in a high impregnation rate, thereby improving battery performance.

[0116] In one embodiment of the present invention, examples of the polyolefin-based separator substrate component include high density polyethylene, linear low density polyethylene, low density polyethylene, ultra-high molecular weight polyethylene, polypropylene, or derivatives thereof.

[0117] In one embodiment of the present invention, the separator has a separator excess portion that extends beyond the width of the positive electrode and the negative electrode on both sides in the width direction, and a coating layer that is thicker than the separator is formed on one or both sides of the separator excess portion to prevent shrinkage of the separator.

[0118] In one embodiment of the present invention, the separation membrane excess portions may each have a size of 5% to 12% based on the width of the separation membrane.

[0119] In one embodiment of the present invention, the coating layer may be coated on both sides of the separator with a width that is 50% to 90% of the width of the remaining portion of the separator on one side, and the widths of the coating layers on both sides may be the same or different.

[0120] In one embodiment of the present invention, the thickness of the coating layer may be smaller than the thickness of the first electrode or the second electrode. In a specific example, the thickness of the coating layer may be 30% to 99% of the thickness of the first electrode or the second electrode.

[0121] In one embodiment of the present invention, the coating layer may be formed by wet coating or dry coating. In one embodiment of the present invention, the coating layer may be an active layer.

[0122] In one embodiment of the present invention, the substrate and the coating layer are present in a form where the pores on the surface of the polyolefin-based separator substrate and the coating layer are intertwined with each other, thereby enabling a strong physical bond between the separator substrate and the active layer. In this case, the substrate and the active layer may have a thickness ratio of 9:1 to 1:9, specifically 5:5, taking into consideration the physical bonding strength and the pore structure on the separator.

[0123] In one embodiment of the present invention, the coating layer may contain inorganic particles and a binder polymer.

[0124] In one embodiment of the present invention, the inorganic particles may be inorganic particles commonly used in the art. The inorganic particles function both to form micropores by forming void spaces between the inorganic particles and as a kind of spacer that maintains the physical shape. In addition, the inorganic particles generally have the property of not changing their physical properties even at high temperatures of 200°C or higher, so the formed organic / inorganic composite porous film has excellent heat resistance.

[0125] In addition, the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are those that can be used in the operating voltage range of the applied battery (e.g., Li / Li +There are no particular limitations on the inorganic particles, as long as they do not undergo oxidation and / or reduction reactions at a voltage (0 V to 5 V as a reference). In particular, when inorganic particles with ion-transfer ability are used, the ionic conductivity in the electrochemical device can be increased to improve performance, so the ionic conductivity is preferably as high as possible. Furthermore, if the inorganic particles have a high density, it is not only difficult to disperse them during coating, but also there is the problem of increased weight during battery production, so the density is preferably as low as possible. Furthermore, inorganic particles with a high dielectric constant can contribute to an increase in the degree of dissociation of the electrolyte salt, e.g., lithium salt, in the liquid electrolyte, thereby improving the ionic conductivity of the electrolyte solution.

[0126] For the reasons mentioned above, the inorganic particles may be one or more selected from the group consisting of inorganic particles having piezoelectricity and inorganic particles having lithium ion transport ability.

[0127] The piezoelectric inorganic particles are non-conductors under normal pressure, but when a certain pressure is applied, they change their internal structure and become electrically conductive. They not only exhibit high dielectric constant characteristics with a dielectric constant of 100 or more, but also generate electric charges when stretched or compressed by applying a certain pressure, generating a potential difference between the two surfaces by charging one side positively and the other side negatively.

[0128] When inorganic particles having the above characteristics are used as a coating layer component, if an internal short circuit occurs between the anode and cathode due to an external impact such as a needle-shaped conductor, the inorganic particles coated on the separator not only prevent the cathode and cathode from coming into direct contact with each other, but also generate a potential difference within the particles due to the piezoelectricity of the inorganic particles. This allows electrons to move between the anode and cathode, i.e., a minute current flow, resulting in a gradual decrease in the battery voltage and improved safety.

[0129] Examples of the inorganic particles having piezoelectricity may include, but are not limited to, one or more selected from the group consisting of BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT), PB(Mg3Nb 2 / 3 )O3 - PbTiO3 (PMN - PT), and hafnia (HfO2).

[0130] The inorganic particles having lithium ion transfer ability are inorganic particles that contain lithium element but do not store lithium and have the function of moving lithium ions. The inorganic particles having lithium ion transfer ability can transfer and move lithium ions due to a kind of defect existing inside the particle structure, so the lithium ion conductivity in the battery is improved, and thereby the battery performance can be improved.

[0131] Examples of the inorganic particles having lithium ion transfer ability may include, but are not limited to, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 < x < 2, 0 < y < 3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), (LiAlTiP) x O y (0 < x < 4, 0 < y < 13) series glass, lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate (Li x Ge y P z S w , 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (Li x N y , 0 < x < 4, 0 < y < 2), SiS2 (Li x Siy S z ,(0 < x < 3, 0 < y < 2, 0 < z < 4) series glass, and P2S5 (Li x P y S z , (0 < x < 3, 0 < y < 3, 0 < z < 7) series glass, and may be one or more selected from the group consisting of, but is not limited thereto.

[0132] The composition ratio of the inorganic particles and the binder polymer as the coating layer component is not particularly restricted, but can be adjusted within the range of 10:90 to 99:1% by weight, and the range of 80:20 to 99:1% by weight is preferable. When it is less than the 10:90 weight ratio, the content of the polymer becomes excessively large, the size and porosity of the pores due to the reduction of the empty space formed between the inorganic particles are reduced, and the final battery performance is decreased. Conversely, when it exceeds the 99:1 weight ratio, since the content of the polymer is excessively small, the mechanical properties of the final organic / inorganic composite porous separation membrane may be decreased due to the weakening of the adhesion force between the inorganics.

[0133] The coating layer in the organic / inorganic composite porous separation membrane may further contain other known additives in addition to the aforementioned inorganic particles and binder polymer. In one embodiment of the present invention, the coating layer may also serve as an active layer.

Example

[0134] As described above, the present invention has been described in detail by specific embodiments, but this is for specifically explaining the present invention, and the manufacturing apparatus for the electrode assembly according to the present invention is not limited thereto. Various implementations are possible by those having ordinary knowledge in the art within the technical idea of the present invention.

[0135] <Manufacture of electrode assembly> 1) Example 1 An interface was formed between the organic binder solution and the aqueous binder solution in a coating solution containing an organic binder and an aqueous binder, and a separator was then run through the interface. After passing through the interface, the separator was dried, forming an organic binder layer and an aqueous binder layer on each side of the separator. At the same time, the separator with the organic binder layer and the aqueous binder layer formed on each side was fed to a stacking table. Also, 19 positive electrodes and 20 negative electrodes were fed to the stacking table.

[0136] As described above, the positive electrode, negative electrode, and separator were fed to a stacking table, and the separator was folded to stack the positive electrode, negative electrode, and separator. Specifically, the positive electrode and negative electrode were alternately arranged between the folded separators on the stacking table to produce a stack using 39 electrodes. The stack was then heated and pressurized at a temperature of 60°C and a pressure of 2 MPa for 15 seconds (time condition) to produce the electrode assembly of Example 1.

[0137] 2) Comparative Example 1 The separator was run through a coating solution containing only an aqueous binder, and after passing through the coating solution, the separator was dried to form an aqueous binder layer on both sides. At the same time, the separator with the aqueous binder layer formed on both sides was fed to a stacking table. Additionally, 19 positive electrodes and 20 negative electrodes were fed to the stacking table. An electrode assembly of Comparative Example 1 was fabricated using the same method as in Example 1.

[0138] 3) Comparative Example 2 The separator was run through a coating solution containing only an organic binder, and after passing through the coating solution, the separator was dried to form an organic binder layer on both sides. At the same time, the separator with the organic binder layer formed on both sides was fed to a stacking table. Additionally, 19 positive electrodes and 20 negative electrodes were fed to the stacking table. An electrode assembly of Comparative Example 2 was fabricated using the same method as in Example 1.

[0139] <Experimental example - Adhesion strength measurement> For the electrode assemblies of Example 1 and Comparative Examples 1 and 2, samples of the positive electrode and separator and the negative electrode and separator positioned in the same order were prepared. Specifically, the samples were 20 mm wide and 20 mm long. Each sample was attached to adhesive tape, and the separator of the sample was pulled perpendicularly from the adhesive tape. The value at which the separator peeled from the electrode was measured and defined as the adhesive strength. For reference, OPP packaging tape (box tape) was used as the adhesive tape.

[0140] [Table 1]

[0141] From the results in Table 1, it was confirmed that the adhesive strength between the anode and separator and the adhesive strength between the cathode and separator were not only strong but also uniform in Example 1. In Comparative Example 1, the adhesive strength between the anode and separator and the adhesive strength between the cathode and separator were uniform but weak, and in Comparative Example 2, the adhesive strength between the positive electrode and separator was strong but weak, confirming that the adhesive strength between the anode and separator and the adhesive strength between the positive electrode and separator were not uniform.

[0142] That is, it was confirmed that when a separator having an organic binder layer and an aqueous binder layer formed on each side of the separator as in Example 1 is used, it is possible to manufacture an electrode assembly that not only has strong adhesive strength but also has uniform performance.

[0143] In addition, Example 1 was found to have excellent process efficiency because it was possible to simultaneously coat one side of the separation membrane with an aqueous binder and the other side of the separation membrane with an organic binder by utilizing a method in which an interface between an aqueous binder and an organic binder is separated in a coating solution and the separation membrane passes through the interface. [Explanation of symbols]

[0144] 1, 2, 3, 4, 5...Travel rollers 10...electrode assembly 11...1st electrode 11a First electrode tab 12...Second electrode 12a Second electrode tab 14...Separation membrane 50 ···First Press Department 50a, 50b: A pair of first pressure blocks 51 Gripper 51a Main body 51b...Fixed part 60 ···Second Press Department 60a, 60b: A pair of second pressure blocks 100, 200 Electrode assembly manufacturing apparatus 110 Stack Table 111 Table body 112 Stack Table Heater 120...Separation membrane supply section 121...Separation membrane heating section 122 Separation membrane roll 130...1st electrode supply section 131 First electrode seating table 132 First electrode heater 133 First electrode roll 134 First cutter 135 No. 1 Conveyor Belt 136 First electrode supply head 140...Second electrode supply section 141 Second electrode seating table 142 Second electrode heater 143 Second electrode roll 144 Second cutter 145 Second conveyor belt 146 Second electrode supply head 150 First electrode stack section 151 First suction head 151a...Vacuum inlet 151b...Bottom surface 152 First head heater 153 First moving part 160 Second electrode stack section 161 Second suction head 162 Second head heater 163 Second moving part 170 ···Holding mechanism 171 First holding mechanism 172 Second holding mechanism 180 ···Press Department 181 First pressure block 182 Second pressure block 183, 184 Press heater S ···Laminate A Coating liquid B...interface C. Organic binder solution D: Water-based binder solution

Claims

1. A method for manufacturing an electrode assembly in which first and second electrodes are alternately arranged between folded separators, comprising: providing the first electrode to a stack table; providing the second electrode to a stack table; feeding the separation membrane onto a stack table; and stacking the stacked structure, in which the first electrodes and the second electrodes are alternately arranged between the folded separators, on a stack table; Including, The step of supplying the separation membrane to the stack table includes: simultaneously coating one surface of the separation membrane with an aqueous binder and coating the other surface of the separation membrane with an organic binder; and providing a separator having two surfaces coated with different binders; A method for manufacturing an electrode assembly, comprising:

2. The step of simultaneously coating one surface of the separation membrane with an aqueous binder and the step of simultaneously coating the other surface of the separation membrane with an organic binder includes: preparing a coating liquid containing the organic binder and the aqueous binder; phase-separating the coating liquid to form an interface between the organic binder and the aqueous binder; and simultaneously coating both sides of the separator while moving the separator through the interface; The method for manufacturing the electrode assembly of claim 1 , comprising:

3. 3. The method of claim 1, wherein the aqueous binder is at least one selected from the group consisting of an aqueous acrylic copolymer, CMC, a polyacrylic acid copolymer, a polyacrylamide copolymer, SBR, a water-dispersible urethane copolymer, and a urea copolymer.

4. 3. The method of claim 1, wherein the organic binder is at least one selected from the group consisting of polyvinylidene fluoride (PVDF) copolymers, organic acrylic copolymers, urethane copolymers, polyamide copolymers, polyimide copolymers, and polyacrylonitrile copolymers.

5. the method further includes coating one of the first electrode and the second electrode with a coating liquid containing the aqueous binder, and coating the other of the first electrode and the second electrode with a coating liquid containing the organic binder; the surface of the separation membrane coated with the aqueous binder is in contact with the surface of the electrode coated with the aqueous binder, of the first electrode or the second electrode; 3. The method of claim 1, wherein the other surface of the separator coated with the organic binder is in contact with the surface of the electrode coated with the organic binder.

6. the electrode coated with the aqueous binder is a negative electrode; The method of manufacturing an electrode assembly according to claim 5 , wherein the electrode coated with the organic binder is a positive electrode.

7. An electrode assembly in which first and second electrodes are alternately arranged between folded separators, The separation membrane is coated on both sides with different binders, One surface of the separation membrane includes an aqueous binder coating layer, the other surface of the separator includes an organic binder coating layer; the first electrode has a surface coated with a water-based binder; the second electrode has a surface coated with an organic binder; the aqueous binder coating layer of the separator is in contact with the first electrode; The electrode assembly, wherein the organic binder coating layer of the separator is in contact with the second electrode.

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