Electrode assembly and method for manufacturing electrode assembly

Abstract

The present invention relates to an electrode assembly manufacturing method in which a first electrode and a second electrode are alternately arranged between folded separators, the electrode assembly manufacturing method comprising the steps of: supplying the first electrode to a stacking table; supplying a second electrode to the stacking table; supplying the diaphragm to a stacking table; and stacking, on a stacking table, a stacking material in which the first electrodes and the second electrodes are alternately arranged between the folded diaphragms, wherein the step of supplying the separator to the stacking table includes simultaneously performing a step of coating one surface of the separator with an aqueous adhesive and a step of coating the other surface of the separator with an organic adhesive, and supplying the separator whose two surfaces are coated with different adhesives.

Description

Technical Field

[0001] This application claims the priority and benefit of Korean Patent Application No. 10-2022-0174039, filed with the Korean Intellectual Property Office on December 13, 2022, the entire content of which is incorporated herein by reference.

[0002] The present invention relates to an electrode assembly and a method of manufacturing the same. Background Art

[0003] Unlike primary batteries, secondary batteries can be recharged and can be formed in small sizes or large capacities. Therefore, a great deal of research and development on secondary batteries is underway. As the technological development and demand for mobile devices grow, the demand for secondary batteries as an energy source is increasing rapidly.

[0004] According to the shape of the battery case, secondary batteries can be classified into coin-type batteries, cylindrical batteries, square batteries, and pouch-type batteries. In a secondary battery, an electrode assembly installed in the battery case is a rechargeable power generation device having a structure in which electrodes and a separator are stacked.

[0005] Electrode assemblies can be roughly classified into: a jelly-roll type electrode assembly in which a separator is inserted between a positive electrode and a negative electrode each 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; a stacked type electrode assembly in which a plurality of positive electrodes and negative electrodes are sequentially stacked with a separator therebetween; and a stacked and folded type electrode assembly in which stacked unit cells are wound with a separator having a long length.

[0006] Here, in a zigzag-folded type electrode assembly, the electrode assembly is manufactured using a plurality of electrodes in a state where the separator is folded in a zigzag form and the electrodes are located between the folded separators.

[0007] In this process, when the separator is supplied to the stacking table, there is a problem that the separator wrinkles or is misaligned, resulting in the manufactured electrode assembly being a defective product or having deteriorated performance.

[0008] Therefore, there is a need for a process condition or method to eliminate wrinkles or misalignment defects in the separator supplied in the manufacturing process of the electrode assembly. Summary of the Invention

[0009] Technical Problem

[0010] The present invention is directed to providing an electrode assembly and a method of manufacturing the same.

[0011] Technical Solution

[0012] An exemplary embodiment of the present invention provides a method for manufacturing an electrode assembly, in which a first electrode and a second electrode are alternately arranged between folded separators. The method includes: supplying the first electrode to a stacking table; supplying the second electrode to the stacking table; supplying the separator to the stacking table; and stacking a stack in which the first electrode and the second electrode are alternately arranged between the folded separators on the stacking table, wherein supplying the separator to the stacking table includes: simultaneously coating one surface of the separator with an aqueous adhesive and coating the other surface of the separator with an organic adhesive; and supplying the separator having two surfaces coated with different adhesives.

[0013] In addition, an exemplary embodiment of the present invention provides an electrode assembly, in which a first electrode and a second electrode are alternately arranged between folded separators, wherein two surfaces of the separator are coated with different adhesives, and one surface of the separator includes an aqueous adhesive coating, and the other surface of the separator includes an organic adhesive coating, wherein the first electrode has a surface coated with an aqueous adhesive, wherein the second electrode has a surface coated with an organic adhesive, wherein the aqueous adhesive coating on the separator contacts the first electrode, and wherein the organic adhesive coating on the separator contacts the second electrode.

[0014] Advantageous Effects

[0015] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present application can improve the process efficiency.

[0016] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present application can improve the adhesion between the electrode and the separator in the prepared electrode assembly. Therefore, the electrode assembly manufactured by the method for manufacturing an electrode assembly according to an exemplary embodiment of the present application has excellent performance.

[0017] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present application can provide an electrode assembly having uniform and excellent performance. Brief Description of the Drawings

[0018] Figure 1 is a diagram schematically showing a method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention.

[0019] Figure 2 is a plan view schematically showing an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0020] Figure 3 is a front view showing the concept of an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0021] Figure 4 FIG. 1 is a cross-sectional view schematically showing an electrode assembly manufactured by an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0022] Figure 5 FIG. 2 is a perspective view schematically showing a pressing unit in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention and a state in which the pressing unit presses a stack.

[0023] Figure 6 (a) is a perspective view showing a first pressing unit 50 according to an exemplary embodiment of the present invention, Figure 6 (b) is a perspective view showing a second pressing unit 60 according to an exemplary embodiment of the present invention.

[0024] Figure 7 FIG. 3 is a perspective view showing a stacking table in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0025] Figure 8 FIG. 4 is a perspective view showing a first electrode placement table in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0026] Figure 9 FIG. 5 is a perspective view showing a second electrode placement table in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0027] Figure 10 FIG. 6 is a perspective view showing a first suction head in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0028] Figure 11 FIG. 7 is a bottom view showing a first suction head in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0029] Figure 12 FIG. 8 is a plan view showing a holding mechanism and a stacking table in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0030] 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 them. However, the present invention can be implemented in various different forms and is not limited to the configurations described herein.

[0031] When a part of this specification "includes", "contains", or "has" a component, unless otherwise specifically stated, this does not mean excluding other components, but means that other components can also be included.

[0032] In this specification, "p to q" refers to the range of "equal to or greater than p and equal to or less than q".

[0033] In this specification, an "organic binder coating" or an "organic binder layer" refers to a layer formed by coating an organic binder, and an "aqueous binder coating" or an "aqueous binder layer" refers to a layer formed by coating an aqueous binder.

[0034] When describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the gist of the present invention will be omitted.

[0035] An exemplary embodiment of the present invention provides a method for manufacturing an electrode assembly, in which a first electrode and a second electrode are alternately arranged between folded separators. The method includes: supplying the first electrode to a stacking table; supplying the second electrode to the stacking table; supplying the separator to the stacking table; and stacking, on the stacking table, a stacked body in which the first electrode and the second electrode are alternately arranged between the folded separators. The supplying of the separator to the stacking table includes: simultaneously coating one surface of the separator with an aqueous binder and coating the other surface of the separator with an organic binder; and supplying the separator having two surfaces coated with different binders.

[0036] In this specification, the stacked form in which the first electrode and the second electrode are alternately arranged between the folded separators is referred to as a zigzag fold.

[0037] The method for manufacturing an electrode assembly according to the present invention has the following features: the step of coating one surface of the separator with an aqueous binder and the step of coating the other surface of the separator with an organic binder are performed simultaneously, and the two different types of coating are performed simultaneously, so that the process efficiency can be improved. In addition, by coating the two surfaces of the separator with an aqueous binder and an organic binder respectively, the adhesion between the first electrode and the second electrode and the separator can be improved. Thus, an electrode assembly with uniform and excellent performance can be provided.

[0038] In an exemplary embodiment of the present invention, the step of simultaneously coating one surface of the separator with an aqueous binder and coating the other surface of the separator with an organic binder may include: preparing a coating solution containing the organic binder and the aqueous binder; phase-separating the coating solution to form an interface between the organic binder and the aqueous binder; and while moving the separator through the interface, simultaneously coating the two surfaces of the separator.

[0039] In an exemplary embodiment of the present invention, based on 100 parts by weight of the coating solution, the coating solution may contain the aqueous binder in an amount of 0.1 to 20 parts by weight, and based on 100 parts by weight of the coating solution, the coating solution may contain the organic binder in an amount of 0.1 to 30 parts by weight.

[0040] In an exemplary embodiment of the present invention, based on 100 parts by weight of the coating solution, the coating solution may contain the aqueous binder in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1 to 12 parts by weight.

[0041] In an exemplary embodiment of the present invention, based on 100 parts by weight of the coating solution, the coating solution may contain the organic binder in an amount of 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight, more preferably 5 to 15 parts by weight.

[0042] When the content of the coating solution is satisfied, it is possible to improve the adhesion between the electrode and the separator while preventing problems of deterioration of battery performance due to a decrease in ionic conductivity.

[0043] The method for manufacturing an electrode assembly according to an embodiment of the present invention may further include: drying the coating after coating one surface of the separator with the aqueous binder and coating the other surface of the separator with the organic binder.

[0044] In an exemplary embodiment of the present invention, the step of drying the coating may be performed at a temperature of 50°C to 70°C, preferably 55°C to 65°C.

[0045] Figure 1 Schematically shows a method for manufacturing an electrode assembly according to the present invention. Referring to Figure 1 and 2 , during the process of supplying the separator 14 from the separator supply unit 120, the separator 14 passes through the coating solution (A), as shown in Figure 1 . More specifically, the coating solution (A) contains an organic binder and an aqueous binder, and phase separation occurs between the organic binder and the aqueous binder in the coating solution (A), such that an interface (B) is formed between the organic binder solution (C) and the aqueous binder solution (D). In this case, the separator 14 passes through the interface (B) between the organic binder and the aqueous binder. In this case, the travel interval may be determined in consideration of the size of the electrode assembly to be manufactured, etc., and the separator may travel and move through a plurality of travel rollers 1, 2, 3, 4, and 5.

[0046] The separator 14 that has passed through the interface (B) between the organic binder and the aqueous binder is dried at a predetermined temperature, thereby forming an organic binder layer and an aqueous binder layer on the two surfaces of the separator 14, respectively. Different from the conventional method, the method for manufacturing an electrode assembly according to the present invention enables two different types of binders to be coated on the two surfaces of the separator 14 simultaneously by using the method through the interface (B) between the organic binder and the aqueous binder. Therefore, the above effects can be achieved.

[0047] In an exemplary embodiment of the present invention, the aqueous binder may be one or more selected from the group consisting of an aqueous acrylic copolymer, carboxymethyl cellulose (CMC), a polyacrylic acid copolymer, a polyacrylamide copolymer, styrene-butadiene rubber (SBR), a water-dispersible polyurethane copolymer, and a urea copolymer.

[0048] In an exemplary embodiment of the present invention, the organic binder may be one or more selected from the group consisting of a polyvinylidene fluoride (PVdF) copolymer, an organic acrylic copolymer, a polyurethane copolymer, a polyamide copolymer, a polyimide copolymer, and a polyacrylonitrile copolymer.

[0049] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may further include: coating one of the first electrode and the second electrode with a coating solution containing an aqueous binder, and coating the other electrode with a coating solution containing an organic binder, and one surface of the separator coated with the aqueous binder may be in contact with the coated surface of the electrode coated with the aqueous binder among the electrodes, and the other surface of the separator coated with the organic binder may be in contact with the coated surface of the electrode coated with the organic binder among the electrodes.

[0050] More specifically, in an exemplary embodiment of the present invention, the electrode coated with the aqueous binder may be the negative electrode, and the electrode coated with the organic binder may be the positive electrode.

[0051] That is, in order to improve the adhesion between the electrode and the separator, it is desirable to use the same type of binder for the binder coated on the positive electrode and the binder contained in the coating formed on the surface of the separator facing the positive electrode. This also applies to the negative electrode.

[0052] Generally, an organic binder is used for the positive electrode and an aqueous binder is used for the negative electrode. Therefore, when the positive electrode is in contact with the binder layer on the corresponding separator surface, the adhesion between the separator and the electrode can be further improved.

[0053] Generally speaking, aqueous adhesives have excellent adhesion to negative electrodes (graphite-based, silicon-based) using aqueous slurries, and organic adhesives have excellent adhesion to positive electrodes using organic slurries. Therefore, when using a separator applied with an organic adhesive, its adhesion to the negative electrode decreases, thereby increasing the gap between the negative electrode and the separator, resulting in a high possibility of precipitation occurring at the upper part of the cell.

[0054] Therefore, by using an organic adhesive on the positive electrode adhesion surface side of the separator and an aqueous adhesive on the negative electrode adhesion surface side of the separator, the adhesion between the positive electrode, the separator, and the negative electrode can be improved simultaneously, thereby preventing precipitation on the cell.

[0055] In an exemplary embodiment of the present invention, the step of stacking the stack on the stacking table may include: stacking a separator (S1) on the stacking table; stacking a first electrode on the upper surface of the separator (S2); covering the upper surface of the first electrode by supplying a separator while rotating the stacking table (S3); and stacking a second electrode on the separator covering the upper surface of the first electrode (S4), and steps S1 to S4 may be repeated more than once.

[0056] In an exemplary embodiment of the present invention, the method may further include: when stacking the first electrode or the second electrode on the stacking table, clamping and fixing the first electrode or the second electrode to the stacking table by using a holding mechanism.

[0057] The method for manufacturing an electrode assembly according to an exemplary embodiment of the present invention may further include heating and pressing the stack stacked on the stacking table.

[0058] In an exemplary embodiment of the present invention, the step of heating and pressing the stack may include: moving the stack between a pair of pressing blocks; moving the pair of pressing blocks in a direction facing each other toward the stack and performing surface pressing on the stack; and heating the stack by using a pressing heater. Additionally, the pressing heater may be included in each of the pressing blocks.

[0059] In an exemplary embodiment of the present invention, the step of heating and pressing the stack may be performed under temperature conditions of 55°C or higher and 70°C or lower, pressure conditions of 1.5 MPa or higher and 3 MPa or lower, and time conditions of 5 seconds or longer and 20 seconds or shorter.

[0060] Here, the pressure condition refers to the pressure applied by the pair of pressing blocks (or the pressing blocks on the stacking table), and the temperature condition refers to the temperature of the heat applied by the pressing heater.

[0061] An exemplary embodiment of the present invention provides an apparatus for manufacturing an electrode assembly by stacking a first electrode, a separator, and a second electrode. The apparatus includes: a stacking table on which the first electrode, the separator, and the second electrode are stacked in a form in which the first electrode and the second electrode are alternately arranged between the folded separators; a separator supply unit configured to supply the separator toward the stacking table side; a first electrode supply unit configured to supply the first electrode; a second electrode supply unit configured to supply the second electrode; a first electrode stacking unit configured to stack the first electrode supplied from the first electrode supply unit on the stacking table; a second electrode stacking unit configured to stack the second electrode supplied from the second electrode supply unit on the stacking table; and a pressing unit configured to adhere the first electrode, the separator, and the second electrode to each other by heating and pressing the stack of the first electrode, the separator, and the second electrode stacked on the stacking table.

[0062] In this case, as described in the method for manufacturing the electrode assembly, the separator supply unit simultaneously performs the process of coating one surface of the two surfaces of the separator with an aqueous adhesive and coating the other surface of the separator with an organic adhesive, and then supplies the separator toward the stacking table side.

[0063] In an exemplary embodiment of the present invention, the separator supply unit may include a separator tension control unit for adjusting the tension of the supplied separator.

[0064] In an exemplary embodiment of the present invention, the apparatus may further include a holding mechanism configured to hold and fix the first electrode or the second electrode to the stacking table when the first electrode or the second electrode is stacked on the stacking table.

[0065] In an exemplary embodiment of the present invention, the pressing unit may further include a pair of pressing blocks and a pressing heater for heating the pressing blocks, and may be configured such that the pair of pressing blocks move in a direction facing each other and perform surface pressing on the stack while heating the stacked body.

[0066] In an exemplary embodiment of the present invention, the pressing heater may be included in each of the pressing blocks.

[0067] In an exemplary embodiment of the present invention, the pressing unit may be configured to adhere the first electrode, the separator, and the second electrode to each other by heating and pressing a stack of the first electrode, the separator, and the second electrode under a temperature condition of above 55°C and below 70°C, a pressure condition of above 1.5 MPa and below 3 MPa, and a time condition of above 5 seconds and below 20 seconds.

[0068] Here, the pressure condition refers to the pressure applied by the pair of pressing blocks (or the pressing block on the stacking table), and the temperature condition refers to the temperature of the heat applied by the pressing heater.

[0069] In an exemplary embodiment of the present invention, the first electrode supply unit may include a first electrode placement table on which the first electrode is placed before being stacked on the stacking table by the first electrode stacking unit, and the second electrode supply unit may include a second electrode placement table on which the second electrode is placed before being stacked on the stacking table by the second electrode stacking unit.

[0070] In addition, in an exemplary embodiment of the present invention, the first electrode stacking unit may include a first suction head for vacuum-adsorbing the first electrode placed on the first electrode placement table, and the second electrode stacking unit may include a second suction head for vacuum-adsorbing the second electrode placed on the second electrode placement table.

[0071] In an exemplary embodiment of the present invention, the device may further include a rotation unit configured to rotate the stacking table. In order to perform zigzag folding in such a manner that the separator is located between the first electrode and the second electrode, the first electrode stacking unit may be provided on one side of the rotation unit, the second electrode stacking unit may be provided on the other side of the rotation unit, and the rotation unit may be configured to alternately perform the following operations: when stacking the first electrode, rotating the stacking table towards one side so as to face the first suction head of the first electrode stacking unit; when stacking the second electrode, rotating the stacking table towards the other side so as to face the second suction head of the second electrode stacking unit.

[0072] An exemplary embodiment of the present invention provides an electrode assembly, in which a first electrode and a second electrode are alternately arranged between folded separators, wherein two surfaces of the separator are coated with different adhesives, one surface of the separator includes an aqueous adhesive coating, the other surface of the separator includes an organic adhesive coating, wherein the first electrode has a surface coated with an aqueous adhesive, wherein the second electrode has a surface coated with an organic adhesive, wherein the aqueous adhesive coating on the separator contacts the first electrode, and wherein the organic adhesive coating on the separator contacts the second electrode.

[0073] That is to say, in this specification, the description of the electrode assembly manufacturing apparatus can be applied to the manufacturing method of the electrode assembly and the electrode assembly, and vice versa.

[0074] Hereinafter, reference will be made to Figures 1 to 12 The electrode assembly manufacturing apparatus and the manufacturing method of the electrode assembly of the present invention will be described in more detail.

[0075] Figure 2 is a plan view schematically showing an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention, Figure 3 is a front view showing the concept of the electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention. Here, for convenience, in Figure 2 the holding mechanism 170 and the pressing unit 180 shown in Figure 3 are omitted, and in Figure 3 the separator supply unit 120 shown in Figure 2 is omitted.

[0076] In this specification, the "holding mechanism" is used to clamp the stacked body stacked on the stacking table during the process of manufacturing a stacked body in which the first electrode, the separator, and the second electrode are stacked in a form in which the first electrode and the second electrode are alternately arranged between folded separators, so that the first electrode or the second electrode is stacked, and has a different function from the gripper that clamps the stacked body during the heating and pressing processes.

[0077] Refer to Figures 1 to 3, the electrode assembly manufacturing apparatus 100 according to an exemplary embodiment of the present invention includes: a stacking table 110; a separator supply unit 120 for supplying a separator 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 stacking table 110; a second electrode stacking unit 160 for stacking the second electrode 12 on the stacking table 110; and a pressing unit 180 for adhering the first electrode 11, the separator 14, and the second electrode 12 therebetween. Additionally, the electrode assembly manufacturing apparatus 100 according to an 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 stacking the electrodes on the stacking table 110. In this case, the foregoing Figure 1 description may be applicable to the separator supplied from the separator supply unit.

[0078] Additionally, in an exemplary embodiment of the present invention, the first electrode, the separator, and the second electrode may be supplied to the stacking table while being heated.

[0079] That is, the separator supply unit may supply the separator to the stacking table while heating the separator, and the first electrode supply unit and the second electrode supply unit may supply the first electrode and the second electrode to the stacking table while heating the first electrode and the second electrode, respectively.

[0080] Figure 4 is a cross-sectional view schematically showing an electrode assembly manufactured by an electrode assembly manufacturing apparatus or an electrode assembly manufacturing method according to an exemplary embodiment of the present invention. In this case, an organic binder layer and an aqueous binder layer are respectively formed on two surfaces of the separator, and the above description may be applicable to the electrodes in contact with the layers.

[0081] Referring to Figures 1 to 4 , the electrode assembly manufacturing apparatus 100 according to an exemplary 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.

[0082] As Figure 4As shown, the electrode assembly 10 is generally a charge-dischargeable power generation element, which can be formed in a form where the first electrode 11, the separator 14, and the second electrode 12 are alternately stacked and assembled. Here, the electrode assembly 10 can have the following form: for example, the separator 14 is folded into a zigzag shape, and the first electrode 11 and the second electrode 12 are alternately arranged between the folded separators 14. In this case, the electrode assembly 10 can be arranged in a form where the separator 14 surrounds the outermost part of the electrode assembly. As described above, the organic binder layer and the aqueous binder layer are respectively formed on two surfaces of the separator 14.

[0083] In addition, as Figure 2 shown, the separator supply unit 120 may further include a separator roll 122 around which the separator 14 is wound. The separator wound around the separator roll can be gradually unwound and supplied to the stacking table. That is, the separator can be in the form of a separator sheet. In this case, the separator 14 supplied through the separator heating unit 121 can be heated and supplied while the separator tension is adjusted by the above-mentioned tension control unit (not shown).

[0084] Referring to Figure 5 , the pressing unit 180 may further include a pair of pressing blocks 181 and 182, and pressing heaters 183 and 184 included in the pair of pressing blocks 181 and 182. In this case, the pair of pressing blocks 181 and 182 can move in a direction facing each other to perform surface pressing on the stack S, which can be heated by the pressing heaters 183 and 184. The foregoing description can be applied to the heating and pressure conditions.

[0085] In addition, in an exemplary embodiment of the present application, the pressing unit can be divided into a first pressing unit and a second pressing unit. The first pressing unit can be defined as a unit that heats and presses the stack while clamping the stack by a gripper; the second pressing unit can be defined as a unit used for secondary heating and pressing of the stack that has been preliminarily heated and pressed by the first pressing unit without clamping by a gripper. In this case, the description of the foregoing pressing unit can be applied to the heating and pressure conditions of the first pressing unit and the second pressing unit.

[0086] Regarding this point, Figure 6 (a) is a perspective view showing a first pressing unit 50 according to an exemplary embodiment of the present invention, Figure 6 (b) is a perspective view showing a second pressing unit 60 according to an exemplary embodiment of the present invention.

[0087] Referring to Figure 6(a), while the first pressing unit 50 fixes the stack S by means of the gripper 51, it heats and presses the stack S. The first pressing unit 50 includes a pair of first pressing blocks 50a and 50b, and the pair of first pressing blocks 50a and 50b have flat pressing surfaces for pressing, except for the grooves corresponding to the fixing portions 51b of the gripper 51.

[0088] The gripper 51 may include a main body 51a whose size corresponds to or is larger than the length (x) and height (y) of the stack S; and a plurality of fixing portions 51b, and the fixing portions 51b are respectively provided on one surface of the main body 51a and extend in the width (z) direction of the stack S in a columnar or plate-like shape. Here, the length (x) of the stack S may refer to the part with the longest distance from one end to the other end of the stack S, the height (y) may refer to the distance in the stacking direction of the stack S, and the width (z) may refer to the distance across the upper surface of the stack S.

[0089] The fixing portions 51b can be adjusted in position in the height direction of the main body 51a so that the fixing portions 51b can fix the stack S while contacting the upper and lower surfaces of the stack S. Then, the pair of first pressing blocks 50a and 50b of the first pressing unit 50 move in a direction facing each other, thereby performing surface pressing on one or more of the stack S and the gripper 51, so that the electrodes and the separator included in the stack S can be adhered.

[0090] Refer to Figure 6 (b), the second pressing unit 60 can finally heat and press the stack S that has been preliminarily heated and pressed by the first pressing unit 50. The second pressing unit 60 includes a pair of second pressing blocks 60a and 60b, and the pair of second pressing blocks 60a and 60b can perform surface pressing on the stack S while moving in a direction facing each other. In addition, the pair of second pressing blocks 60a and 60b of the second pressing unit 60 may have pressing surfaces for contacting and pressing the stack S, and the pressing surfaces are all flat surfaces.

[0091] Figure 7 is a perspective view of a stacking table in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0092] Refer to Figure 3 and 7 , the first electrode 11, the separator 14, and the second electrode 12 can be stacked on the stacking table 110 in such a form that the first electrode 11 and the second electrode 12 are alternately arranged between the folded separators 14.

[0093] In addition, the stacking table 110 may include: a table main body 111 on which the first electrode 11, the separator 14, and the second electrode 12 are stacked; and a stacking table heater 112 that heats the stacked stack S by heating the table main body 111.

[0094] The first electrode 11 may be configured as a positive electrode, and the second electrode 12 may be configured as a negative electrode, but the present invention is not necessarily limited thereto. For example, the first electrode 11 may be configured as a negative electrode, and the second electrode 12 may be configured as a positive electrode.

[0095] Figure 8 is a perspective view of the first electrode placement table in the electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0096] Referring to Figure 3 and 8 , the first electrode supply unit 130 may supply the first electrode 11 to the first electrode stacking unit 150 while heating the first electrode 11.

[0097] In addition, the first electrode supply unit 130 may include: a first electrode placement table 131 on which the first electrode 11 is placed before being stacked on the stacking table 110 by the first electrode stacking unit 150; and a first electrode heater 132 that heats the first electrode 11 by heating the first electrode placement table 131.

[0098] It should be noted that the first electrode supply unit 130 may further include: a first electrode roll 133 on which a sheet-like first electrode 11 is wound; a first cutter 134 that cuts the sheet-like first electrode 11 at regular intervals when the sheet-like first electrode 11 wound on the first electrode roll 133 is unwound and supplied, thereby forming the first electrode 11 having a predetermined size; a first conveyor belt 135 that moves the first electrode 11 cut by the first cutter 134; and a first electrode supply head 136 that vacuum-adsorbs the first electrode 11 conveyed by the first conveyor belt 135 and places it on the first electrode placement table 131. Here, the first cutter 134 may cut the sheet-like first electrode 11 such that a first electrode tab 11a protruding at the end is formed.

[0099] Figure 9 is a perspective view of the second electrode placement table in the electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0100] Referring to Figure 3 and 9 , the second electrode supply unit 140 may supply the second electrode 12 to the second electrode stacking unit 160 while heating the second electrode 12.

[0101] In addition, the second electrode supply unit 140 may include: a second electrode placement table 141 on which the second electrode 12 is placed before being stacked on the stacking table 110 through the second electrode stacking unit 160; and a second electrode heater 142 that heats the second electrode 12 by heating the second electrode placement table 141.

[0102] It should be noted that the second electrode supply unit 140 may further include: a second electrode roll 143 around which the sheet-like second electrode 12 is wound; a second cutter 144 that cuts the second electrode 12 at regular intervals when the sheet-like second electrode 12 wound around the second electrode roll 143 is unwound and supplied, thereby forming the second electrode 12 having a predetermined size; a second conveyor belt 145 that moves the second electrode 12 cut by the second cutter 144; and a second electrode supply head 146 that vacuum-adsorbs the second electrode 12 conveyed by the second conveyor belt 145 and places it on the second electrode placement table 141. Here, the second cutter 144 may cut the sheet-like second electrode 12 such that a second electrode tab 12a protruding at the end is formed.

[0103] In an exemplary embodiment of the present invention, the first electrode stacking unit may include a first suction head for vacuum-adsorbing the first electrode placed on the first electrode placement table, and the second electrode stacking unit may include a second suction head for vacuum-adsorbing the second electrode placed on the second electrode placement table.

[0104] Figure 10 is a perspective view showing a first suction head in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention, Figure 11 is a bottom view showing a first suction head in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0105] Referring to Figure 2 、 3 、10 and 11, the first electrode stacking unit 150 can stack the first electrode 11 on the stacking table 110.

[0106] In addition, the first electrode stacking unit 150 may include a first suction head 151 and a first moving part 153.

[0107] The first suction head 151 can vacuum-adsorb the first electrode 11 placed on the first electrode placement stage 131. In this case, the first suction head 151 has vacuum adsorption holes 151a formed on the bottom surface 151b, and can adsorb the first electrode 11 through the vacuum adsorption holes 151a, thereby fixing the first electrode 11 to the bottom surface 151b of the first suction head 151. Here, a channel connecting the vacuum adsorption holes 151a and a vacuum adsorption device (not shown) can be formed in the first suction head 151.

[0108] The first moving part 153 can move the first suction head 151 to the stacking stage 110, so that the first suction head 151 can stack the first electrode 11 placed on the first electrode placement stage 131 on the stacking stage 110.

[0109] In addition, the second electrode stacking unit 160 can stack the second electrode 12 on the stacking stage 110. Here, the second electrode stacking unit 160 can have the same structure as the above-mentioned first electrode stacking unit 150. In this case, the second electrode stacking unit 160 can include a second suction head 161 and a second moving part 163.

[0110] The second suction head 161 can vacuum-adsorb the second electrode 12 placed on the second electrode placement stage 141.

[0111] The second moving part 163 can move the second suction head 161 to the stacking stage 110, so that the second suction head 161 can stack the second electrode 12 placed on the second electrode placement stage 141 on the stacking stage 110.

[0112] Figure 12 is a plan view showing a holding mechanism and a stacking stage in an electrode assembly manufacturing apparatus according to an exemplary embodiment of the present invention.

[0113] Referring to Figure 3 and 12 , when the first electrode 11 or the second electrode 12 is stacked on the stacking stage 110, the holding mechanism 170 can fix the first electrode 11 or the second electrode 12 to the stacking stage 110 while clamping the first electrode 11 or the second electrode 12.

[0114] In addition, when stacking the first electrode 11 on the stacking stage 110, the holding mechanism 170 can press and fix the upper surface of the first electrode 11 stacked on the uppermost side of the stacking stage 110; when stacking the second electrode 12 on the stacking stage 110, the holding mechanism 170 can press and fix the upper surface of the second electrode 12 stacked on the uppermost side of the stacking stage 110. In addition, the holding mechanism can press and fix the upper surface of the stack of the first electrode 11, the separator 14, and the second electrode 12 stacked on the stacking stage 110.

[0115] That is, when forming a stacked body while positioning and stacking the first electrode 11 and the second electrode 12 between the folded separator 14, the holding mechanism 170 clamps the uppermost surface of the stacked body in such a way as to press the uppermost surface of the stacked body toward the stacking table 110, thereby preventing the stacked body from separating from the stacking table 110.

[0116] It should be noted that the holding mechanism 170 may include, for example, a first holding mechanism 171 and a second holding mechanism 172, and is capable of fixing both sides of the first electrode 11 or the second electrode 12.

[0117] Then, when the holding mechanism 170 clamps the first electrode 11 or the second electrode 12 and rotates the stacking table 110, the separator 14 can be unwound from the separator roll 122 and supplied to the side of the stacking table 110.

[0118] In addition, the first electrode and the second electrode may be stacked in an alternating arrangement between the folded separators by moving the stacking table or the separator left and right. In this case, after the holding mechanism 170 clamps the first electrode 11 or the second electrode 12, the stacking table 110 or the separator 14 moves left and right, causing the separator 14 to be unwound from the separator roll 122 and supplied to the side of the stacking table 110. It should be noted that, for example, the stacking table 110 may be connected or combined with a stacking table moving part (not shown) to move left and right, and the separator may be supplied to the stacking table while moving left and right through a separator guiding part (not shown).

[0119] 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.

[0120] In an exemplary embodiment of the present invention, the first electrode may be a negative electrode, and the second electrode may be a positive electrode.

[0121] In addition, in an exemplary embodiment of the present invention, the positive electrode is manufactured, for example, by applying a mixture of a positive electrode active material, a conductive material, and a binder onto a positive electrode current collector, then drying it, and if necessary, adding a filler to the mixture. Regarding the materials used in this case, materials commonly used in the art may be used.

[0122] Specifically, examples of the positive electrode active material may include layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals; lithium manganese oxide, such as the chemical formula Li 1+x Mn 2-xO4 (where x is from 0 to 0.33), LiMnO3, LiMn2O3 and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiFe3O4, V2O5 and Cu2V2O7; LiNi represented by the chemical formula 1-x M x O2 (where M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x is from 0.01 to 0.3) represents Ni-site type lithium nickel oxide; LiMn represented by the chemical formula 2-x M x O2 (where M is Co, Ni, Fe, Cr, Zn or Ta, and x is from 0.01 to 0.1) or Li2Mn3MO8 (where M is Fe, Co, Ni, Cu or Zn) represents lithium manganese composite oxide; LiMn2O4 in which a part of Li in the chemical formula is replaced by alkaline earth metal ions; disulfide compounds; and Fe2(MoO4)3, but not limited thereto.

[0123] Specifically, the positive electrode current collector is not particularly limited as long as it has high conductivity and does not cause chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, fired carbon can be used, and aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. respectively. Specifically, aluminum can be used. The positive electrode current collector may have fine irregularities formed on the surface to enhance the adhesion of the positive electrode active material, and can be used in various forms such as films, sheets, foils, meshes, porous bodies, foams or non-woven fabric bodies. In addition, the thickness of the positive electrode current collector is generally in the range of 3 μm to 500 μm.

[0124] Based on the total weight of the mixture containing the positive electrode active material, the addition amount of the conductive material is generally 1 to 50% by weight. The conductive material is not particularly limited as long as it has conductivity and does not cause chemical changes in the battery. For example, graphite such as natural graphite or artificial graphite can be used; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black and thermal cracking carbon black; conductive fibers such as carbon fibers and metal fibers; fluorocarbon powder; metal powders such as aluminum powder and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc.

[0125] The binder is a component that aids in the binding of the active material, the conductive material, etc., and the binding to the current collector. Based on the total weight of the mixture containing the positive electrode active material, the usual addition amount of the binder is 1 to 50% by weight. Examples of such binders can include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluororubber, various copolymers, etc.

[0126] The filler is selectively used as a component for suppressing the swelling of the positive electrode, and there is no particular limitation as long as it is a fibrous material that does not cause chemical changes in the battery. For example, olefin-based polymers such as polyethylene and polypropylene can be used; and fibrous materials such as glass fiber and carbon fiber can be used.

[0127] In addition, in an exemplary embodiment of the present invention, the negative electrode is manufactured by applying, drying, and pressing the negative electrode active material on the negative electrode current collector, and if necessary, it may also optionally contain the conductive material, binder, filler, etc. as described above. In addition, in this case, materials commonly used in the art can be used.

[0128] Specifically, as the negative electrode active material, for example, carbon such as non-graphitizable carbon and graphite-based carbon can be used; such as Li x Fe2O3(0≤x≤1), Li x WO2(0≤x≤1) and Sn x Me 1-x Me' y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of Groups 1, 2, and 3 of the periodic table, and halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8) metal composite oxides; lithium metal; lithium alloys; silicon-based alloys; tin-based alloys; 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.

[0129] There is no particular limitation on such a negative electrode current collector, as long as it has conductivity and does not cause chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum cadmium alloy, etc. can be used. Additionally, similar to the positive electrode current collector, the negative electrode current collector may have fine irregularities formed on its surface to enhance the bonding force of the negative electrode active material, and can be used in various forms such as films, sheets, foils, meshes, porous bodies, foams, or non-woven fabric bodies. Additionally, the thickness of the negative electrode current collector is generally in the range of 3 μm to 500 μm.

[0130] In an exemplary embodiment of the present invention, the separator may be an organic / inorganic composite porous SRS (safety enhanced separator). The SRS may have a structure in which a coating composition containing inorganic particles and a binder polymer is applied to a polyolefin-based separator substrate.

[0131] Due to the heat resistance of the inorganic particles, the SRS does not undergo high-temperature thermal shrinkage, so even if the electrode assembly is penetrated by a needle-shaped conductor, it can maintain the extended length of the safety separator.

[0132] Based on the pore structure contained in the separator substrate itself, the SRS may also have a uniform pore structure formed by the interstitial volume between the inorganic particles as the coating composition. These pores can not only significantly mitigate any external impact applied to the electrode assembly, but also promote the migration of lithium ions through the pores, and enable a large amount of electrolyte to be impregnated into the separator, thereby promoting battery performance improvement.

[0133] In an exemplary embodiment of the present invention, examples of the polyolefin-based separator substrate components may include high-density polyethylene, linear low-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, and their derivatives.

[0134] In an exemplary embodiment of the present invention, the separator has separator remaining portions that extend beyond the widths of the positive electrode and the negative electrode on both sides in the width direction, and has a structure in which a coating thicker than the thickness of the separator is formed on one surface or both surfaces of both side portions of the separator remaining portions to prevent the separator from shrinking.

[0135] In an exemplary embodiment of the present invention, the separator remaining portions may each have a size of 5% to 12% of the width of the separator.

[0136] In an exemplary embodiment of the present invention, the coating may be coated on both surfaces of the separator with a size of 50% to 90% based on the width of the separator remaining portion on one side. Additionally, the widths of the coatings on the two surfaces may be the same or different from each other.

[0137] In an exemplary embodiment of the present invention, the thickness of the coating may be less than the thickness of the first electrode or the second electrode. In a specific example, the thickness of the coating may be 30% to 99% of the thickness of the first electrode or the second electrode.

[0138] In an exemplary embodiment of the present invention, the coating may be formed by wet coating or dry coating.

[0139] In an exemplary embodiment of the present invention, the coating may be referred to as an active layer.

[0140] In an exemplary embodiment of the present invention, the polyolefin-based separator substrate and the coating may exist in a form in which the pores on the surface of the substrate and the coating are anchored to each other, whereby the separator substrate and the active layer can be firmly physically bonded. In this case, considering the physical bonding force and the pore structure present in the separator, the thickness ratio of the substrate to the active layer may be 9:1 to 1:9, and specifically 5:5.

[0141] In an exemplary embodiment of the present invention, the coating may contain inorganic particles and a binder polymer.

[0142] In an exemplary embodiment of the present invention, the inorganic particles may be inorganic particles commonly used in the art. The inorganic particles can form voids between the inorganic particles to act as pores, and also act as a spacer capable of maintaining a physical shape. In addition, since the inorganic particles generally have the property of not changing their physical properties even at high temperatures above 200 °C, the resulting organic / inorganic composite porous membrane has excellent heat resistance.

[0143] In addition, there is no particular limitation on the inorganic particles as long as they are electrochemically stable. That is, there is no particular limitation on the inorganic particles that can be used in the present invention as long as they do not undergo oxidation and / or reduction reactions within the operating voltage range of the battery to which they are applied (for example, 0 to 5 V based on Li / Li+). In particular, the use of inorganic particles having ion transport ability can promote performance improvement by increasing the ion conductivity in the electrochemical device. Therefore, it is preferable to use inorganic particles having as high an ion conductivity as possible. In addition, when the inorganic particles have a high density, it is difficult to disperse the inorganic particles during coating, and there is also a problem of weight increase during battery manufacturing. Therefore, it is preferable to use inorganic particles having as low a density as possible. In addition, inorganic materials having a high dielectric constant contribute to increasing the dissociation degree of electrolyte salts (such as lithium salts) in the liquid electrolyte, thereby improving the ion conductivity of the electrolyte.

[0144] For the above reasons, the inorganic particles may be one or more types selected from the group consisting of inorganic particles having piezoelectricity and inorganic particles having lithium ion transport ability.

[0145] The inorganic particles having piezoelectricity refer to materials that are non-conductive under normal pressure but have the physical property of conductivity due to changes in the internal structure when a certain pressure is applied. The inorganic particles having piezoelectricity are also materials that exhibit high dielectric constant characteristics with a dielectric constant of 100 or more. The inorganic particles having piezoelectricity are also materials that, when stretched or compressed by applying a certain pressure, generate a potential difference between opposite surfaces due to the generated charges, causing one surface to be positively charged and the other surface to be negatively charged.

[0146] When using inorganic particles having the above characteristics as a coating component, in the case where the positive electrode and the negative electrode are internally short-circuited due to an external impact such as a needle-shaped conductor, since the inorganic particles are coated on the separator, the positive electrode and the negative electrode may not be in direct contact. In addition, due to the piezoelectricity of the inorganic particles, a potential difference can be generated in the particles, whereby electron movement, that is, the flow of a minute current, can occur between the positive electrode and the negative electrode, resulting in a slow decrease in the battery voltage, thereby improving safety.

[0147] Examples of materials for the inorganic particles having piezoelectricity may be one or more types 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(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3 (PMN-PT), and hafnium dioxide (HfO2), but are not limited thereto.

[0148] The inorganic particles having lithium ion transport ability refer to inorganic particles that contain lithium element but do not store lithium, but have the function of migrating lithium ions. The inorganic particles having lithium ion transport ability can transport and migrate lithium ions due to a kind of defect in the particle structure. As a result, the lithium ion conductivity in the battery can be improved, thereby improving the battery performance.

[0149] Examples of materials for the inorganic particles having lithium ion transport ability may be selected from the group consisting of 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, where 0 < x < 2, 0 < y < 1, 0 < z < 3), ((LiAlTiP) x O y , where 0 < x < 4, 0 < y < 13) series of glasses, lithium lanthanum titanate (Li x La y TiO3, where 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate (Li x Ge y P z S w , where 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (Li x N y , where 0 < x < 4, 0 < y < 2), SiS2 (Li x Si y S z , where 0 < x < 3, 0 < y < 2, 0 < z < 4) series of glasses, and P2S5 (Li x P y S z , where 0 < x < 3, 0 < y < 3, 0 < z < 7) series of glasses, and more than one type in the group consisting of, but not limited to, these.

[0150] There is no particular limitation on the composition ratio of the inorganic particles and the binder polymer as the components of the coating, but it can be adjusted within the range of 10:90 to 99:1 (wt%), preferably within the range of 80:20 to 99:1 (wt%). If the composition ratio is less than 10:90 (wt%), the content of the polymer becomes too large, and since the voids formed between the inorganic particles decrease, the pore size and porosity may decrease, ultimately leading to deterioration of battery performance. On the other hand, if the composition ratio exceeds 99:1 (wt%), the content of the polymer is too small, and since the adhesion force between the inorganic materials weakens, the mechanical properties of the final organic / inorganic composite porous separator may deteriorate.

[0151] Based on the above inorganic particles and binder polymer, the coating of the organic / inorganic composite porous separator may further contain other known additives.

[0152] In an exemplary embodiment of the present invention, the coating may be referred to as an active layer.

[0153] Invention mode

[0154] Although the present invention has been described in detail in conjunction with specific embodiments, this is intended to specifically describe the present invention, and the device for manufacturing an electrode assembly according to the present invention is not limited thereto. Obviously, those skilled in the art can make various implementations within the technical gist of the present invention.

[0155] <Preparation of Electrode Assembly>

[0156] 1) Example 1

[0157] In a coating solution containing an organic binder and an aqueous binder, after an interface is formed between the organic binder solution and the aqueous binder solution, the separator is made to travel through the interface. After passing through the interface, the separator is dried to form an organic binder layer and an aqueous binder layer on the corresponding surfaces of the separator. At the same time, the separator having the organic binder layer and the aqueous binder layer formed on its corresponding surfaces is supplied to a stacking table. In addition, 19 positive electrode sheets and 20 negative electrode sheets are also supplied to the stacking table.

[0158] While supplying the positive electrode, the negative electrode, and the separator to the stacking table, the separator is folded, and the positive electrode, the negative electrode, and the separator are stacked. Specifically, a stack using 39 electrode sheets is prepared by stacking the positive electrode, the negative electrode, and the separator in such a manner that the positive electrode and the negative electrode are alternately arranged between the folded separators on the stacking table. Then, under a temperature condition of 60°C and a pressure condition of 2 MPa, the stack is heated and pressed for 15 seconds (time condition) to prepare the electrode assembly of Example 1.

[0159] 2) Comparative Example 1

[0160] The separator is made to travel through a coating solution containing only an aqueous binder. After passing through the coating solution, the separator is dried to form an aqueous binder layer on both surfaces of the separator. At the same time, the separator having the aqueous binder layer formed on both its surfaces is supplied to a stacking table. In addition, 19 positive electrode sheets and 20 negative electrode sheets are also supplied to the stacking table. Except for the above, the electrode assembly of Comparative Example 1 is prepared in the same manner as Example 1.

[0161] 3) Comparative Example 2

[0162] The separator is made to travel through a coating solution containing only an organic binder. After passing through the coating solution, the separator is dried to form an organic binder layer on both surfaces of the separator. At the same time, the separator having the organic binder layer formed on both its surfaces is supplied to a stacking table. In addition, 19 positive electrode sheets and 20 negative electrode sheets are also supplied to the stacking table. Except for the above, the electrode assembly of Comparative Example 2 is prepared in the same manner as Example 1.

[0163] <Experimental Example - Adhesion Force Measurement>

[0164] In the electrode assemblies of Example 1 and Comparative Examples 1 and 2, samples of the positive electrode and the separator placed in the same order and samples of the negative electrode and the separator were prepared. Specifically, the samples could be taken as 20 mm in width and 20 mm in length. After pasting each sample to the tape, the separator of the sample was peeled off from the tape in the vertical direction. In this case, the value when the separator was peeled off from the electrode was measured and defined as the adhesion force. For reference, packaging OPP tape (shipping box tape) was used as the tape.

[0165]

[0166] From the results in Table 1, it can be confirmed that in Example 1, the adhesion force between the negative electrode and the separator and between the positive electrode and the separator was high and uniform. It can be confirmed that in Comparative Example 1, the adhesion force between the negative electrode and the separator and between the positive electrode and the separator was uniform but low; in Comparative Example 2, the adhesion force between the positive electrode and the separator was high, but the adhesion force between the negative electrode and the separator was low, and the adhesion force between the negative electrode and the separator and between the positive electrode and the separator was non-uniform.

[0167] That is, it can be confirmed that when using a separator having an organic binder layer and an aqueous binder layer formed on the corresponding surfaces of the separator as in Example 1, an electrode assembly having high adhesion force and uniform performance can be manufactured.

[0168] In addition, it can be confirmed that Example 1 also has excellent process efficiency because, by using a method of separating the interface between the aqueous binder and the organic binder in the coating solution and passing the separator through the interface, one surface of the separator can be coated with the aqueous binder and the other surface of the separator can be coated with the organic binder simultaneously.

[0169] [Symbol Explanation]

[0170] 1, 2, 3, 4, 5: Traveling rollers

[0171] 10: Electrode assembly

[0172] 11: First electrode

[0173] 11a: First electrode tab

[0174] 12: Second electrode

[0175] 12a: Second electrode tab

[0176] 14: Separator

[0177] 50: First pressing unit

[0178] 50a, 50b: A pair of first pressing blocks

[0179] 51: Gripper

[0180] 51a: Main body

[0181] 51b: Fixing part

[0182] 60: Second pressing unit

[0183] 60a, 60b: A pair of second pressing blocks

[0184] 100, 200: Electrode assembly manufacturing device

[0185] 110: Stacking table

[0186] 111: Table main body

[0187] 112: Stacking table heater

[0188] 120: Diaphragm supply unit

[0189] 121: Diaphragm heating unit

[0190] 122: Diaphragm roll

[0191] 130: First electrode supply unit

[0192] 131: First electrode placement table

[0193] 132: First electrode heater

[0194] 133: First electrode roll

[0195] 134: First cutter

[0196] 135: First conveyor belt

[0197] 136: First electrode supply head

[0198] 140: Second electrode supply unit

[0199] 141: Second electrode placement table

[0200] 142: Second electrode heater

[0201] 143: Second electrode roll

[0202] 144: Second cutter

[0203] 145: Second conveyor belt

[0204] 146: Second electrode supply head

[0205] 150: First electrode stacking unit

[0206] 151: First suction head

[0207] 151a: Vacuum adsorption hole

[0208] 151b: Bottom surface

[0209] 152: First suction head heater

[0210] 153: First moving part

[0211] 160: Second electrode stack unit

[0212] 161: Second suction head

[0213] 162: Second suction head heater

[0214] 163: Second moving part

[0215] 170: Holding mechanism

[0216] 171: First holding mechanism

[0217] 172: Second holding mechanism

[0218] 180: Pressing unit

[0219] 181: First pressing block

[0220] 182: Second pressing block

[0221] 183, 184: Pressing heaters

[0222] S: Stacked body

[0223] A: Coating solution

[0224] B: Interface

[0225] C: Organic binder solution

[0226] D: Aqueous binder solution

Claims

1. A method for manufacturing an electrode assembly, wherein a first electrode and a second electrode are alternately arranged between folded separators, the method comprising: Supplying the first electrode to a stacking table; Supplying the second electrode to the stacking table; Supplying the separator to the stacking table; And Stacking a stack in which the first electrode and the second electrode are alternately arranged between the folded separators on the stacking table, Wherein the supplying the separator to the stacking table includes: Simultaneously coating one surface of the separator with an aqueous adhesive and coating the other surface of the separator with an organic adhesive, and Supplying the separator having two surfaces coated with different adhesives.

2. The method according to claim 1, wherein the simultaneously coating one surface of the separator with an aqueous adhesive and coating the other surface of the separator with an organic adhesive includes: Preparing a coating solution containing the organic adhesive and the aqueous adhesive, Phase-separating the coating solution so as to form an interface between the organic adhesive and the aqueous adhesive, and While moving the separator through the interface, simultaneously coating both surfaces of the separator.

3. The method according to claim 1, wherein the aqueous adhesive is one or more selected from the group consisting of an aqueous acrylic copolymer, carboxymethyl cellulose (CMC), a polyacrylic acid copolymer, a polyacrylamide copolymer, styrene-butadiene rubber (SBR), a water-dispersible polyurethane copolymer, and a urea copolymer.

4. The method according to claim 1, wherein the organic adhesive is one or more selected from the group consisting of a polyvinylidene fluoride (PVDF) copolymer, an organic acrylic copolymer, a polyurethane copolymer, a polyamide copolymer, a polyimide copolymer, and a polyacrylonitrile copolymer.

5. The method according to claim 1 further comprises: Coating one of the first electrode and the second electrode with a coating solution containing the aqueous adhesive, and coating the other electrode with a coating solution containing the organic adhesive, Wherein one surface of the separator coated with the aqueous adhesive contacts the coating surface of the electrode coated with the aqueous adhesive, and Wherein the other surface of the separator coated with the organic adhesive contacts the coating surface of the electrode coated with the organic adhesive.

6. The method according to claim 5, wherein the electrode coated with the aqueous adhesive is a negative electrode, and Wherein the electrode coated with the organic adhesive is a positive electrode.

7. An electrode assembly, wherein a first electrode and a second electrode are alternately arranged between folded separators, Wherein two surfaces of the separator are coated with different adhesives, Wherein one surface of the separator includes an aqueous adhesive coating, Wherein the other surface of the separator includes an organic adhesive coating, Wherein the first electrode has a surface coated with an aqueous adhesive, Wherein the second electrode has a surface coated with an organic adhesive, Wherein the aqueous adhesive coating on the separator contacts the first electrode, and Wherein the organic adhesive coating on the separator contacts the second electrode.

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