Single-sided electrode, electrode assembly including the same, and method for manufacturing the single-sided electrode

Abstract

A single-sided electrode according to one embodiment of the present invention includes an electrode current collector; an active material layer located on one side of the electrode current collector; and a coating layer located on the other side of the electrode current collector, wherein the coating layer has a thickness smaller than that of the active material layer.

Description

[Technical field]

[0001] Cross-reference to related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0161634 dated November 22, 2021 and Korean Patent Application No. 10-2022-0157376 dated November 22, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a single-sided electrode, an electrode assembly including the same, and an apparatus for manufacturing the single-sided electrode, and more particularly, to a single-sided electrode having controlled curl, an electrode assembly including the same, and an apparatus for manufacturing the single-sided electrode. [Background technology]

[0003] As technological development and demand for mobile devices increases, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting much attention not only for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also as an energy source for power devices such as electric bicycles, electric cars, and hybrid electric cars.

[0004] Such secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is housed in a cylindrical or prismatic metal case, and pouch batteries in which the electrode assembly is housed in a pouch case made of an aluminum laminate sheet, according to the shape of the battery case. Here, the electrode assembly housed in the battery case is a power generating element capable of charging and discharging, which is composed of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode, and is classified into a jelly roll type in which a separator is interposed between a long sheet-type positive electrode and a negative electrode coated with an active material and the separator is wound up, and a stack type in which a plurality of positive electrodes and negative electrodes are stacked in sequence with a separator interposed therebetween.

[0005] Among these, pouch-type batteries, which have a structure in which a stack-type or stack / folding-type electrode assembly is built into a pouch-type battery case made of an aluminum laminate sheet, are increasingly being used due to their low manufacturing cost, small weight, easy modification, etc.

[0006] Here, in the case of a stack-type electrode assembly, a method is generally used in which a unit cell is first manufactured and then a plurality of the unit cells are stacked to manufacture the electrode assembly. More specifically, the unit cells are stacked alternately in the order of separator-anode-separator-cathode, and heat and pressure are applied to the stacked unit cells through a laminating device, thereby fixing each component to each other.

[0007] Generally, a stacked electrode assembly has a structure in which a negative electrode is stacked on the top of a half-cell to ensure cell safety. However, in this case, there is a problem that the energy density is reduced due to the half-cell. Therefore, it is necessary to develop an electrode assembly that can increase the energy density while ensuring cell stability by omitting the half-cell from being placed on the top in the stacked electrode assembly. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a single-sided electrode having controlled curl, an electrode assembly including the same, and an apparatus for manufacturing the single-sided electrode.

[0009] The problems that the present invention is intended to solve are not limited to the problems described above, and problems not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings. [Means for solving the problem]

[0010] A single-sided electrode according to one embodiment of the present invention includes an electrode current collector; an active material layer located on one side of the electrode current collector; and a coating layer located on the other side of the electrode current collector, wherein the coating layer has a thickness smaller than that of the active material layer.

[0011] Specifically, the thickness of the coating layer may be 26% or more and 49% or less of the thickness of the active material layer.

[0012] Here, the coating layer comprises: a) one or more acrylates selected from the group consisting of monofunctional acrylates, difunctional acrylates, and trifunctional acrylates; and b) It may consist of a coating composition containing glass fiber or an epoxy-based resin.

[0013] More specifically, the coating layer is The trifunctional acrylate is present in an amount of 41% by weight or more and 69% by weight or less based on the total weight of the coating composition; The monofunctional acrylate and the difunctional acrylate are present in an amount of 16% by weight or more and 30% by weight or less based on the total weight of the coating composition; The coating composition may include glass fibers in an amount of 13 wt % to 29 wt % based on the total weight of the coating composition.

[0014] Alternatively, the coating layer may be The trifunctional acrylate is present in an amount of 10% by weight or more and 14% by weight or less based on the total weight of the coating composition. The monofunctional acrylate is present in an amount of 5% by weight to 7% by weight based on the total weight of the coating composition. The coating composition may include the epoxy resin in an amount 4 to 5 times the total amount of the trifunctional acrylate and the monofunctional acrylate. The coating composition may further include an initiator and an additive, and the initiator may be a photoinitiator or a mixture of a photoinitiator and a thermal initiator.

[0015] In this case, the total content of the initiator in the coating composition is 1 wt % or more and 4 wt % or less based on the total weight of the coating composition, and the photoinitiator may be included in an amount of 30 wt % to 100 wt % based on the total weight of the initiator, and the additive may be included in an amount of 0.1 wt % or more and 1 wt % or less based on the total weight of the coating composition.

[0016] The curl deviation of the one-sided electrode including the coating layer may be 0 mm or more and 5 mm or less.

[0017] An electrode assembly according to another embodiment of the present invention is an electrode assembly including the single-sided electrode described above, in which a double-sided positive electrode, a double-sided negative electrode, and a separator interposed between the double-sided positive electrode and the double-sided negative electrode are repeatedly stacked, and the single-sided electrode is disposed across the separator such that an active material layer of the single-sided electrode faces the double-sided negative electrode or the double-sided positive electrode located in at least one of a top layer and a bottom layer of the electrode assembly, and the double-sided positive electrode has positive electrode active material layers located on both sides of a positive electrode current collector, and the double-sided negative electrode has negative electrode active material layers located on both sides of a negative electrode current collector.

[0018] Here, the single-sided electrode may have a polarity opposite to that of the double-sided negative electrode or the double-sided positive electrode sandwiching the separator.

[0019] A single-sided electrode manufacturing apparatus according to another embodiment of the present invention is an apparatus for manufacturing the above-mentioned single-sided electrode, and includes: a supply roller for supplying an electrode collector; a first coater for applying an active material composition to one side of the electrode collector to form an active material layer on one side of the electrode collector; and a second coater for applying a coating composition to the other side of the electrode collector to form a coating layer on the other side of the electrode collector.

[0020] The electrode current collector on which the active material layer is formed and which is provided from the first coater may be dried.

[0021] The drying method may further include a pair of rolling rollers for rolling upper and lower surfaces of the electrode current collector on which the dried active material layer is formed.

[0022] The coating layer of the electrode current collector provided from the second coater may be irradiated with ultraviolet (UV) light to perform primary curing.

[0023] At this time, the UV irradiation dose was 0.5 J / cm 2 More than 1J / cm 2 It may be the following.

[0024] The coating composition may further include a heat treatment device for performing a second curing step by subjecting the first cured coating layer to an additional heat treatment.

[0025] In this case, the additional heat treatment can be carried out at 100 to 150° C. for 10 to 30 minutes. Effect of the Invention

[0026] According to an embodiment, the present invention is a single-sided electrode including a coating layer located on the other side of an electrode collector, and the thickness of the coating layer is formed to be smaller than the thickness of the active material layer, thereby controlling curl of the single-sided electrode.

[0027] Additionally, the composition of the coating layer can be adjusted to provide a single sided electrode with improved curl control.

[0028] According to another embodiment, the present invention provides an electrode assembly in which the single-sided electrode is located at the top and / or bottom, thereby ensuring cell stability while increasing energy density.

[0029] According to another embodiment, the present invention provides a single-sided electrode manufacturing apparatus that forms a coating layer on the other side of an electrode collector, and that can control curl of the single-sided electrode.

[0030] Furthermore, when forming the coating layer, an additional heat treatment can be performed in addition to the ultraviolet irradiation, thereby providing an apparatus for manufacturing a single-sided electrode that allows for improved curl control.

[0031] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Brief description of the drawings]

[0032] [Figure 1] FIG. 2 illustrates a single-sided electrode according to one embodiment of the present invention. [Diagram 2] 13A and 13B are diagrams illustrating an electrode assembly according to another embodiment of the present invention. [Diagram 3] FIG. 13 is a diagram showing an electrode assembly according to a comparative example. [Figure 4] FIG. 13 is a diagram showing a single-sided electrode manufacturing apparatus according to another embodiment of the present invention. [Diagram 5] FIG. 13 is a diagram showing how the degree of curl is measured in an experimental example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and is not limited to the embodiments set forth herein.

[0034] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0035] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, the thicknesses of various layers and regions are exaggerated to clearly show the layers and regions. In the drawings, the thicknesses of some layers and regions are exaggerated to facilitate explanation.

[0036] Additionally, throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, but not excluding other elements, unless specifically stated to the contrary.

[0037] Additionally, throughout the specification, the term "in a plane" means the part in question viewed from above, and the term "in cross section" means the part in question viewed from the side on a vertical cross section.

[0038] FIG. 1 is a diagram illustrating a single-sided electrode according to one embodiment of the present invention.

[0039] Referring to FIG. 1, a single-sided electrode 101 according to an embodiment of the present invention includes an electrode current collector 110; an active material layer 150 disposed on one side of the electrode current collector 110; and a coating layer 180 disposed on the other side of the electrode current collector 110.

[0040] Here, the single-sided electrode 101 may refer to an electrode in which an active material layer 150 is formed on only one of both sides of an electrode collector 110. In addition, the single-sided electrode 101 may be a single-sided positive electrode or a single-sided negative electrode.

[0041] As an example, when the single-sided electrode 101 is a single-sided positive electrode, the electrode current collector 110 can be a positive electrode current collector and the active material layer 150 can be a positive electrode active material layer. As another example, when the single-sided electrode 101 is a single-sided negative electrode, the electrode current collector 110 can be a negative electrode current collector and the active material layer 150 can be a negative electrode active material layer.

[0042] In the following description, the single-sided electrode 101 will be described as a single-sided positive electrode, but the description is not limited to this and the same can be applied to the case where the single-sided electrode is a single-sided negative electrode.

[0043] The thickness of the coating layer 180 formed to achieve the effects of the present invention is smaller than the thickness of the active material layer 150. Specifically, the thickness of the coating layer 180 may be 26% to 49% of the thickness of the active material layer 150. More specifically, the thickness of the coating layer 180 may be 25% to 45% of the thickness of the active material layer 150. Most specifically, the thickness of the coating layer 180 may be 30% to 40% of the thickness of the active material layer 150.

[0044] As a result, the thickness of the coating layer 180 included in the single-sided electrode 101 has a thickness within the above-mentioned range, so that the degree of curl of the single-sided electrode 101 can be appropriately controlled, and the single-sided electrode 101 can be easily stacked with other positive and negative electrodes as an electrode assembly unit.

[0045] On the other hand, if the thickness of the coating layer 180 included in the single-sided electrode 101 is excessively large or small beyond the above range, the curl of the single-sided electrode 101 becomes severe, and there is a problem in that it is impossible to stack the electrode assembly together with other positive and negative electrodes.

[0046] Here, the coating layer 180 may be composed of a coating composition including a) one or more acrylates selected from the group consisting of monofunctional acrylates, difunctional acrylates, and trifunctional acrylates, and b) glass fiber or an epoxy-based resin.

[0047] For example, the monofunctional acrylate and the bifunctional acrylate may be one or more substances selected from the group consisting of HDDA (Hexanediol Diacrylate), 2-HEA (2-hydroxyethyl acrylate), 9-EGDA (Ethylene Glycol Diacetate), TTEGDA (Tetra(Ethylene Glycol) Diacrylate), and IOA (Isooctyl Acrylate). However, the monofunctional acrylate and the bifunctional acrylate are not limited thereto, and other monofunctional and / or bifunctional acrylates that can be used in secondary batteries known in the art may also be included in this embodiment.

[0048] For example, the trifunctional acrylate may be one or more materials selected from the group consisting of TMPTA (Trimethylolpropane Triacrylate) and PETA (Pentaerythritol Triacrylate). However, the trifunctional acrylate is not limited thereto, and other trifunctional acrylates known in the art that can be used in secondary batteries may also be included in the present embodiment.

[0049] As an example, the glass fiber may be CRC (Cellulose fiber Reinforced Cement)-12. However, the glass fiber is not limited thereto, and other glass fibers that can be used in secondary batteries known in the art may also be included in this embodiment.

[0050] For example, the epoxy resin may be one or more substances selected from the group consisting of a trifunctional epoxy composite resin having an epoxy equivalent of 135 to 150 g / eq and (3',4'-epoxycyclohexane)methyl 3,4-epoxycyclohexyl carboxylate. Specifically, YH-300 (Kookdo Chemical) may be used as the trifunctional epoxy composite resin, and Celloxide 2021P (daicel) may be used as the (3',4'-epoxycyclohexane)methyl 3,4-epoxycyclohexyl carboxylate. However, the epoxy resin is not limited thereto, and other epoxy resins known in the art that can be used in secondary batteries may also be included in this embodiment.

[0051] More specifically, in one example, the coating layer may be composed of a coating composition in which the trifunctional acrylate is contained in an amount of 41 wt % or more and 69 wt % or less based on the total weight of the coating composition, and the monofunctional acrylate and the difunctional acrylate are contained in an amount of 16 wt % or more and 30 wt % or less based on the total weight of the coating composition.

[0052] In detail, the content of the trifunctional acrylate may be 43 wt% to 65 wt% based on the total weight of the coating composition, and the content of the monofunctional acrylate and the difunctional acrylate may be 16 wt% to 29 wt% based on the total weight of the coating composition. For example, the content of the trifunctional acrylate may be 45 wt% to 60 wt% based on the total weight of the coating composition, and the content of the monofunctional acrylate and the difunctional acrylate may be 18 wt% to 28 wt% based on the total weight of the coating composition.

[0053] As a result, the contents of the trifunctional acrylate, the monofunctional acrylate, and the difunctional acrylate in the coating composition are within the above-mentioned ranges, so that the degree of curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition can be appropriately controlled, and the single-sided electrode 101 can be easily stacked with other positive and negative electrodes as an electrode assembly unit.

[0054] On the other hand, if the content of the trifunctional acrylate, the monofunctional acrylate, and the difunctional acrylate in the coating composition is excessively high or low and deviates from the above range, the curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition is intensified, and there is a problem that it is impossible to stack the single-sided electrode 101 with other positive and negative electrodes as an electrode assembly unit.

[0055] In the coating composition, the content of the glass fiber may be 13 wt % or more and 29 wt % or less based on the total weight of the coating composition. More specifically, the content of the glass fiber may be 14 wt % or more and 28 wt % or less based on the total weight of the coating composition. For example, the content of the glass fiber may be 15 wt % or more and 27 wt % or less based on the total weight of the coating composition.

[0056] As a result, the glass fiber content in the coating composition falls within the above-mentioned range, and the degree of curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition can be appropriately controlled, and the single-sided electrode 101 can be easily stacked with other positive and negative electrodes as an electrode assembly unit.

[0057] On the other hand, if the glass fiber content in the coating composition is excessively high or low and deviates from the above range, the curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition is intensified, and there is a problem that it is impossible to stack the electrode assembly with other positive and negative electrodes.

[0058] On the other hand, in another embodiment, the coating layer is The trifunctional acrylate may be present in an amount of 10% by weight to 14% by weight based on the total weight of the coating composition, the monofunctional acrylate may be present in an amount of 5% by weight to 7% by weight based on the total weight of the coating composition, and the epoxy resin may be present in an amount 4 to 5 times the total content of the trifunctional acrylate and the monofunctional acrylate.

[0059] In particular, the content of the trifunctional acrylate may be 10 wt% to 12 wt% based on the total weight of the coating composition, and the content of the monofunctional acrylate may be 6 wt% to 7 wt% based on the total weight of the coating composition. Also, the epoxy resin may be contained in an amount about 5 times the total content of the trifunctional acrylate and the monofunctional acrylate.

[0060] As a result, the content ratio of the trifunctional acrylate, the monofunctional acrylate, and the difunctional acrylate in the coating composition and the content ratio of the epoxy resin are within the above-mentioned ranges, so that the degree of curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition can be appropriately controlled, and the single-sided electrode 101 can be easily stacked with other positive and negative electrodes in an electrode assembly unit.

[0061] On the other hand, if the content of the trifunctional acrylate and the monofunctional acrylate in the coating composition is outside the above range, or if the content ratio of the epoxy resin is excessively high or low, the curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition is intensified, resulting in a problem that it is impossible to stack the electrode assembly with other positive and negative electrodes.

[0062] Also, in the coating layer 180, the coating composition may further include an initiator and an additive, and the initiator may be a photoinitiator or a mixture of a photoinitiator and a thermal initiator, where the additive may refer to a leveling agent, a surfactant, etc.

[0063] As an example, the photoinitiator may be Darocur TPO (Diphenyl(2,4,6-trimethylbenzoyl)-phosphineoxide). However, the photoinitiator is not limited thereto, and other commonly used photoinitiators may also be included in this embodiment.

[0064] The thermal initiator may be, for example, SI-110L (Sanshin Chemical). However, the thermal initiator is not limited thereto, and other commonly used thermal initiators may also be included in this embodiment.

[0065] As an example, the additive may be one or more substances selected from the group consisting of RS-75 (DIC Corporation) and F477 (DIC Corporation). However, the additive is not limited thereto, and other commonly used additives may also be included in this embodiment.

[0066] In the coating composition, the total content of the initiator may be 1 wt% to 4 wt% based on the total weight of the coating composition, and the additive may be 0.1 wt% to 1 wt% based on the total weight of the coating composition. More specifically, the total content of the initiator may be 1.5 wt% to 3 wt% based on the total weight of the coating composition, and in this case, the photoinitiator may be included in an amount of 30 wt% to 100 wt% based on the total weight of the initiator.

[0067] As a result, the contents of the initiator and additives in the coating composition are within the above-mentioned ranges, so that the degree of curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition can be appropriately controlled, and the single-sided electrode 101 can be easily stacked with other positive and negative electrodes as an electrode assembly unit.

[0068] On the other hand, if the content of the initiator and additive in the coating composition is excessively high or low and deviates from the above range, the curl of the single-sided electrode 101 including the coating layer 180 made of the coating composition is intensified, and there is a problem that it is impossible to stack the electrode assembly with other positive and negative electrodes.

[0069] The deviation in the curl degree of the single-sided electrode 101 manufactured in this manner may be 0 mm or more and 5 mm or less. More specifically, the deviation in the curl degree of the single-sided electrode 101 may be 0 mm or more and 4.5 mm or less. As an example, the deviation in the curl degree of the single-sided electrode 101 may be 0 mm or more and 4 mm or less, most specifically, 0 mm to 3 mm.

[0070] Therefore, the degree of curl of the single-sided electrode 101 may have a deviation within the above-mentioned range, so that the electrode assembly may be easily stacked with other positive and negative electrodes.

[0071] On the other hand, if the curl degree of the single-sided electrode 101 deviates from the above-mentioned range and has an excessively large deviation, there is a problem that it is impossible to stack the electrode assembly together with other positive and negative electrodes.

[0072] FIG. 2 is a diagram showing an electrode assembly according to another embodiment of the present invention.

[0073] 2, an electrode assembly according to another embodiment of the present invention includes a single-sided electrode 101 (a single-sided positive electrode 101 which is one of the positive electrodes 100). More specifically, the electrode assembly may include a double-sided positive electrode 102 (a double-sided positive electrode 102 which is one of the positive electrodes 100), a double-sided negative electrode 200, and a separator 300 interposed between the double-sided positive electrode 102 and the double-sided negative electrode 200, which are repeatedly stacked. Here, the double-sided positive electrode 102 has positive electrode active material layers 150 disposed on both sides of a positive electrode current collector (electrode current collector 110), and the double-sided negative electrode 200 has negative electrode active material layers 250 disposed on both sides of a negative electrode current collector 210.

[0074] The positive electrode current collector (electrode current collector 110) is not particularly limited as long as it is conductive and does not induce chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used.

[0075] The positive electrode active material layer 150 may be prepared by attaching or coating a positive electrode slurry containing a positive electrode active material onto a positive electrode current collector (electrode current collector 110), and the positive electrode slurry may further include a conductive material and a polymer material in addition to the positive electrode active material.

[0076] The positive electrode active material is, for example, lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 );Lithium manganese oxide;Lithium copper oxide (Li 2 CuO 2);Vanadium oxide;Ni-site type lithium nickel oxide;Lithium manganese composite oxide;Lithium manganese composite oxide with spinel structure;Chemical formula Li is partially replaced by alkaline earth metal ions, LiMn 2 O 4 ;Disulfide compounds;Fe 2 (MoO 4 ) 3 etc.

[0077] The negative electrode current collector 210 is not particularly limited as long as it has high conductivity without inducing a chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used.

[0078] The negative electrode active material layer 250 may be prepared by attaching or coating a negative electrode slurry containing a negative electrode active material onto the negative electrode current collector 210, and the negative electrode slurry may further include a conductive material and a polymer material in addition to the negative electrode active material.

[0079] The negative active material may be any negative active material for lithium secondary batteries commonly used in the art, such as lithium metal, lithium alloy, petroleum coke, activated carbon, graphite, silicon, tin, metal oxides, or other carbons.

[0080] The separator 300 separates the double-sided positive electrode 102 and the double-sided negative electrode 200, the single-sided electrode 101 and the double-sided negative electrode 200, or the positive electrode (double-sided positive electrode 102) from each other, and provides a path for the movement of lithium ions. Any separator that is normally used as a separator in a lithium secondary battery can be used without any particular restrictions, and it is particularly preferable that the separator has low resistance to the movement of electrolyte ions and excellent electrolyte humidification ability.

[0081] Here, the single-sided electrode 101 may be disposed in the uppermost or lowermost stage of the electrode assembly. More specifically, the single-sided electrode 101 may be disposed with a separator 300 interposed therebetween such that an active material layer of the single-sided electrode 101 faces a double-sided negative electrode 200 or a double-sided positive electrode 102 disposed in at least one of the uppermost and lowermost stages of the electrode assembly.

[0082] 2, the single-sided electrode 101 may be disposed at a position sandwiching the separator 300 so that the active material layer faces the double-sided negative electrode 200 located at the top of the electrode assembly. However, the present invention is not limited thereto, and the single-sided electrode 101 may be disposed at a position sandwiching the separator 300 so that the active material layer faces the double-sided negative electrode 200 or double-sided positive electrode 102 located at the bottom of the electrode assembly.

[0083] As shown in FIG. 2, the single-sided electrode 101 can be disposed such that the active material layer 150 contained in the single-sided electrode 101 contacts the inner separator 300 .

[0084] In addition, the single-sided electrode 101 may have an opposite polarity to the double-sided negative electrode 200 or double-sided positive electrode 102 sandwiching the separator 300. More specifically, as shown in FIG. 2, when the single-sided electrode 101 is a single-sided positive electrode, the single-sided electrode 101 may be disposed at a position sandwiching the separator 300 with the double-sided negative electrode 200 located at at least one of the uppermost and lowermost stages of the electrode assembly. Conversely, when the single-sided electrode 101 is a single-sided negative electrode, the single-sided electrode 101 may be disposed at a position sandwiching the separator 300 with the double-sided positive electrode 102 located at at least one of the uppermost and lowermost stages of the electrode assembly.

[0085] Although not shown in FIG. 2, the electrode assembly may further include a separator 300 in contact with the coating layer 180 of the single-sided electrode 101 located at the top and / or bottom of the electrode assembly.

[0086] As a result, the electrode assembly according to the present embodiment has a single-sided electrode 101 disposed at the top and / or bottom of the electrode assembly, thereby increasing the energy density of the electrode assembly compared to the conventional method while ensuring cell safety.

[0087] FIG. 3 is a diagram showing an electrode assembly according to a comparative example.

[0088] 3, the electrode assembly according to the comparative example is formed by repeatedly stacking a double-sided positive electrode 10, a double-sided negative electrode 20, and a separator 30 interposed between the double-sided positive electrode 10 and the double-sided negative electrode 20. In this case, the electrode assembly may have a double-sided negative electrode 20 disposed at the top and bottom of the electrode assembly, and the outermost active material layer of the double-sided negative electrode 20 at the top and bottom of the electrode assembly does not participate in the reaction. As a result, the double-sided negative electrode 20 is disposed at the top and bottom of the electrode assembly, thereby ensuring cell safety, but there is a problem in that the energy density of the electrode assembly is reduced because the double-sided negative electrode 20 does not participate in the reaction.

[0089] In contrast, the electrode assembly according to the present embodiment has a single-sided electrode 101 disposed at the top and / or bottom of the electrode assembly as described above, thereby increasing the energy density of the electrode assembly compared to the conventional method while ensuring cell safety.

[0090] FIG. 4 is a diagram showing a single-sided electrode manufacturing apparatus according to another embodiment of the present invention.

[0091] 4, a single-sided electrode manufacturing apparatus 1000 according to another embodiment of the present invention is an apparatus for manufacturing a single-sided electrode 101. More specifically, the single-sided electrode manufacturing apparatus 1000 according to the present embodiment includes a supply roller 1100 for supplying an electrode collector 110, a first coater 1200 for coating one side of the electrode collector 110 with an active material composition to form an active material layer 150 on one side of the electrode collector 110, and a second coater 1500 for coating the other side of the electrode collector 110 with a coating composition to form a coating layer 180 on the other side of the electrode collector 110.

[0092] In addition, in the single-sided electrode manufacturing apparatus 1000 according to the present embodiment, the electrode collector 110 on which the active material layer 150 is formed and provided from the first coater 1200 may be dried. Here, the single-sided electrode manufacturing apparatus 1000 according to the present embodiment may further include a separate drying apparatus adjacent to the first coater 1200.

[0093] In addition, the single-sided electrode manufacturing apparatus 1000 according to the present embodiment may further include a pair of rolling rollers 1300 for rolling the upper and lower surfaces of the electrode collector 110 on which the dried active material layer 150 is formed. More specifically, the pair of rolling rollers 1300 may include a first rolling roller 1310 positioned adjacent to the lower part of the electrode collector 110 and a second rolling roller 1350 positioned adjacent to the upper part of the electrode collector 110. Here, the first rolling roller 1310 and the second rolling roller 1350 may be disposed in a vertical direction based on the electrode collector 110.

[0094] In addition, in the single-sided electrode manufacturing apparatus 1000 according to the present embodiment, the coating layer 180 of the electrode collector 110 provided by the second coater 1500 may be irradiated with ultraviolet light (UV) to perform primary curing. For example, the ultraviolet light (UV) may be irradiated by a light source such as an H-bulb. Here, the irradiation dose of the ultraviolet light (UV) is 0.5 J / cm. 2 More than 1J / cm 2 It may be the following.

[0095] If the irradiation amount is too high and deviates from the above range, the curing is excessive, resulting in problems such as cracking of the coating layer. Conversely, if the irradiation amount is too low, the curing is insufficient, resulting in problems of deterioration of the mechanical properties of the coating layer, which is undesirable.

[0096] With the above configuration, the single-sided electrode manufacturing apparatus 1000 according to this embodiment can easily manufacture the single-sided electrode 101 with a controlled degree of curl.

[0097] Although not shown in the drawings, the single-sided electrode manufacturing apparatus 1000 may further include a heat treatment device for performing additional heat treatment on the primarily cured coating layer 180 for secondary curing.

[0098] The additional heat treatment not only allows a flatter single-sided electrode with less curl to be produced, but also improves the interfacial adhesion between the coating layer 180 and the electrode current collector 110 .

[0099] In this case, the additional heat treatment may be carried out at 100 to 150° C. for 10 to 30 minutes or less.

[0100] If the heat treatment is carried out at an excessively high temperature or for an excessively long period outside the above range, it may not be effective in controlling curling and may cause cracks in the coating layer. Conversely, if the heat treatment is carried out at an excessively low temperature or for an excessively short period, the effect of the heat treatment may not be fully obtained, which is undesirable.

[0101] Also, it is more preferable that the heat treatment is carried out after the first curing using UV as described above. If the heat treatment is carried out first, it is difficult to control curling by UV irradiation that is carried out later, but if the heat treatment is carried out after UV irradiation, the part that has shrunk in the direction of the coating layer due to UV can be alleviated by the heat treatment, making it easier to control curling.

[0102] Hereinafter, the present invention will be described in detail with reference to more specific examples. However, the following examples are provided for illustrative purposes only and are not intended to limit the scope of the present invention. EXAMPLES

[0103] <Example 1> A positive electrode current collector having a size of 10 cm x 10 cm and a thickness of 15 μm was prepared by forming a positive electrode active material layer having a thickness of 60 μm on the upper surface of an aluminum (Al) foil and forming a coating layer having a thickness of 20 μm on the lower surface of the aluminum foil.

[0104] Here, the positive electrode active material layer is made of LiNi 0.6 Mn 0.2 Co 0.2 O 2 The cathode active material layer may be made of a cathode active material slurry prepared by mixing the cathode active material, the conductive material, and the binder in a weight ratio of 96:2:2, using carbon black as a conductive material and polyvinylidene fluoride (PVdf), and adding NMP solvent to the mixture. In addition, the cathode active material layer of the single-sided cathode is manufactured by applying the cathode active material slurry to the upper surface of an aluminum foil, followed by drying and rolling.

[0105] The coating layer may be made of a coating liquid in which the trifunctional acrylate:monofunctional / bifunctional acrylate:glass fiber:photoinitiator:additive is mixed in a weight ratio of 50:25:20:5:0.1 or less using Miramer M320 (TMPTA) from Migen as a trifunctional acrylate, Miramer M200 (HDDA) as a monofunctional / bifunctional acrylate, CRC-12 (glass frit) as a glass fiber, Darocur TPO from BASF as a photoinitiator, and F-477 from DIC as an additive (leveling agent). In addition, for a single-sided positive electrode, the coating layer is formed by applying the coating liquid to the lower surface of an aluminum foil and then curing with UV (0.5 J / cm). 2 ) was carried out.

[0106] <Example 2> In Example 1, the coating layer had a thickness of 25 μm. Except for this, a single-sided positive electrode was prepared in the same manner as in Example 1.

[0107] <Example 3> In Example 1, Miramer M2770 (TTEGDA) was used as the monofunctional / bifunctional acrylate, RS-75 from DIC was used as the additive (leveling agent), and the coating solution was prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 50:27:20:2.9:0.1. Here, the coating layer had a thickness of 25 μm. Except for this, a single-sided positive electrode was prepared in the same manner as in Example 1.

[0108] <Example 4> In Example 3, the coating solution was prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 60:22:15:2.9:0.1. A single-sided positive electrode was prepared in the same manner as in Example 3, except for this.

[0109] <Example 5> In Example 3, the coating solution was prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 60:17:20:2.9:0.1. A single-sided positive electrode was prepared in the same manner as in Example 3, except for this.

[0110] <Comparative Example 1> The coating layer was not formed in Example 1. Except for this, a single-sided positive electrode was prepared in the same manner as in Example 1.

[0111] <Example 6> In Example 1, the coating layer had a thickness of 15 μm. Except for this, a single-sided positive electrode was prepared in the same manner as in Example 1.

[0112] <Example 7> In Example 1, the coating layer had a thickness of 30 μm. Except for this, a single-sided positive electrode was prepared in the same manner as in Example 1.

[0113] <Example 8> In Example 1, the coating layer had a thickness of 35 μm. Except for this, a single-sided positive electrode was prepared in the same manner as in Example 1.

[0114] <Example 9> In Example 3, the coating solution was prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 60:30:7:2.9:0.1. A single-sided positive electrode was prepared in the same manner as in Example 3, except that the coating solution was mixed trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 60:30:7:2.9:0.1.

[0115] <Example 10> In Example 3, the coating solution was prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 50:32:15:2.9:0.1. A single-sided positive electrode was prepared in the same manner as in Example 3, except for this.

[0116] <Example 11> In Example 3, the coating solution may be prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 70:15:12:2.9:0.1. A single-sided positive electrode was prepared in the same manner as in Example 3, except for this.

[0117] <Example 12> In Example 3, Miramer M1084 (IOA) was used as the monofunctional / bifunctional acrylate, and the trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive was mixed in a weight ratio of 40:40:17:2.9:0.1 to form a coating solution. A single-sided positive electrode was prepared in the same manner as in Example 3, except for this point.

[0118] <Example 13> In Example 3, the coating solution was prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 50:22:25:2.9:0.1. A single-sided positive electrode was prepared in the same manner as in Example 3, except for this.

[0119] <Example 14> In Example 3, the coating solution was prepared by mixing trifunctional acrylate: monofunctional / bifunctional acrylate: glass fiber: photoinitiator: additive in a weight ratio of 35:42:20:2.9:0.1. A single-sided positive electrode was prepared in the same manner as in Example 3, except for this.

[0120] <Experimental Example 1 (Measurement of curl, pencil hardness, and transmittance depending on coating layer thickness)> For the prepared Examples 1, 2, 6 to 8, and Comparative Example 1, the curl degree and pencil hardness according to the thickness of the coating layer were measured.

[0121] The degree of curl was measured by measuring the distance D between each corner of the positive electrode on one side from the bottom surface to the degree of bending in the (+) or (-) direction based on the electrode as shown in Figure 5, and then calculating the average value. The results are shown in Table 1.

[0122] The pencil hardness was measured using a pencil hardness tester according to the measurement standard JIS K5400, by reciprocating three times with a load of 0.5 kg, and then checking the degree of scratching. The results are shown in Table 1.

[0123] [Table 1]

[0124] Referring to Table 1, Examples 1-2, 6-8, and Comparative Example 1 have coating layers with the same composition, but differ only in the thickness of each coating layer. Here, it can be seen that when the coating layer thickness is 20 μm and 25 μm as in Examples 1 and 2, the curl degree is measured as -0.9 and 1.2, respectively. That is, it can be seen that the single-sided positive electrodes having coating layer thicknesses as in Examples 1 and 2 have the smallest curl degree and excellent pencil hardness.

[0125] In contrast, in the case of Comparative Example 1 where there is no coating layer, the curl level is very large at -24.8, and the pencil hardness is also very poor.

[0126] On the other hand, in Example 6, even when the coating layer was 15 μm thick, it was better than one without a coating layer, but the curl level was measured as −10.4 and the pencil hardness was 1H, indicating that the single-sided positive electrode having a thinner coating layer than those in Examples 1 and 2 had a relatively large curl level and a relatively inferior pencil hardness.

[0127] Also, it can be seen that when the coating layer thickness is 30 μm and 35 μm, respectively, as in Examples 7 and 8, the curl degree is measured as 6.4 and 9.9, respectively. That is, in the case of the single-sided positive electrodes having a thicker coating layer as in Examples 1 and 2, as in Examples 8 and 9, the pencil hardness is excellent, but on the other hand, curling occurs and the curl degree is relatively large.

[0128] This makes it clear that it is all the more important to set an appropriate thickness for the coating layer.

[0129] <Example 15> (About 4 times) A positive electrode current collector having a size of 10 cm x 10 cm and a thickness of 15 μm was prepared by forming a positive electrode active material layer having a thickness of 75 μm on the upper surface of an aluminum (Al) foil and forming a coating layer having a thickness of 30 μm on the lower surface of the aluminum foil.

[0130] Here, the positive electrode active material layer is made of LiNi 0.6 Mn 0.2 Co 0.2 O 2The cathode active material layer may be made of a cathode active material slurry prepared by mixing the cathode active material, the conductive material, and the binder in a weight ratio of 96:2:2, using carbon black as a conductive material and polyvinylidene fluoride (PVdf), and adding NMP solvent to the mixture. In addition, the cathode active material layer of the single-sided cathode is manufactured by applying the cathode active material slurry to the upper surface of an aluminum foil, followed by drying and rolling.

[0131] The coating layer may be made of a coating liquid in which the trifunctional acrylate:monofunctional acrylate:epoxy resin 1:epoxy resin 2:photoinitiator:thermal initiator:additive is mixed in a weight ratio of 12:7:25:53:1.0:1.0:1.0 using pentaerythritol tetraacrylate (PETA) from Miwa Chemical as a trifunctional acrylate, 2-Hydroxy Ethlyacrylate (2-HEA) from Miwa Chemical as a monofunctional acrylate, YH-300 from Kukdo Chemical and Celloxide 2021P from Daicel as an epoxy resin, Darocur TPO from BASF as a photoinitiator, SI-110L from Sanshin Chemical as a thermal initiator, and F-477 from DIC as an additive (surfactant). The coating layer may be made of a coating liquid in which the trifunctional acrylate:monofunctional acrylate:epoxy resin 1:epoxy resin 2:photoinitiator:thermal initiator:additive is mixed in a weight ratio of 12:7:25:53:1.0:1.0:1.0 using ... 2 ) and then heat-treated (120°C, 30 min).

[0132] <Example 16> (About 5 times) In Example 15, the coating solution was prepared by mixing trifunctional acrylate: monofunctional acrylate: epoxy resin 1: epoxy resin 2: photoinitiator: thermal initiator: additive in a weight ratio of 10:6:28:53:1.0:1.0:1.0. A single-sided positive electrode was prepared in the same manner as in Example 15, except for this.

[0133] <Example 17> (About twice as much) In Example 15, the coating solution was prepared by mixing trifunctional acrylate: monofunctional acrylate: epoxy resin 1: epoxy resin 2: photoinitiator: thermal initiator: additive in a weight ratio of 20:14:21:42:1.0:1.0:1.0. A single-sided positive electrode was prepared in the same manner as in Example 15, except for this.

[0134] <Example 18> (About 3 times) In Example 15, the coating solution was prepared by mixing trifunctional acrylate: monofunctional acrylate: epoxy resin 1: epoxy resin 2: photoinitiator: thermal initiator: additive in a weight ratio of 12:10:25:50:1.0:1.0:1.0. A single-sided positive electrode was prepared in the same manner as in Example 15, except for this.

[0135] <Example 19> (About 6 times) In Example 15, the coating solution was prepared by mixing trifunctional acrylate: monofunctional acrylate: epoxy resin 1: epoxy resin 2: photoinitiator: thermal initiator: additive in a weight ratio of 9:5:27:57:0.5:1.0:0.5. A single-sided positive electrode was prepared in the same manner as in Example 15, except that the coating solution was mixed in a weight ratio of 9:5:27:57:0.5:1.0:0.5.

[0136] <Example 20> (About 7 times) In Example 15, the coating solution was prepared by mixing trifunctional acrylate: monofunctional acrylate: epoxy resin 1: epoxy resin 2: photoinitiator: thermal initiator: additive in a weight ratio of 8:4:28:58:0.5:1.0:0.5. A single-sided positive electrode was prepared in the same manner as in Example 16, except for this.

[0137] <Example 21> (About 7 times) A single-sided positive electrode was prepared in the same manner as in Example 15, except that no epoxy resin was used, and a coating solution in which trifunctional acrylate:monofunctional acrylate:photoinitiator:additive was mixed in a weight ratio of 64:32:3.0:1.0 was used, and only UV irradiation was performed without heat treatment.

[0138] <Example 22> (About 7 times) A single-sided positive electrode was prepared in the same manner as in Example 15, except that an acrylate material was not used, and a coating solution in which epoxy resin 1: epoxy resin 2: thermal initiator: additive was mixed in a weight ratio of 33:65:1.0:1.0 was used, and only a heat treatment was performed without UV irradiation.

[0139] <Experimental Example 2 (Curl Degree Measurement According to Coating Layer Composition)> For the prepared Examples 3 to 5 and Examples 9 to 22, curl according to the thickness of the coating layer was measured.

[0140] The degree of curl was measured by measuring the distance D between each corner of the positive electrode on one side from the bottom surface to the (+) or (-) direction based on the electrode as shown in Figure 5, and then calculating the average value. The results are shown in Tables 2 and 3.

[0141] [Table 2]

[0142] [Table 3]

[0143] Referring to Table 2, Examples 3 to 5 and 9 to 14 have the same coating layer thickness, but different coating layer compositions. In this case, it can be seen that the curl degree of the single-sided positive electrodes having the compositions of Examples 3 to 5 was measured as -1 to 1 mm, 1 to 3 mm, and -2 to 3 mm, respectively. That is, it can be seen that the curl degree of the single-sided positive electrodes having the coating layer compositions of Examples 3 to 5 is relatively small. In contrast, it can be seen that the curl degree of the single-sided positive electrodes having the compositions of Examples 9 to 14 was measured as 17 to 18, 7 to 9, not measurable, 14 to 15, not measurable, and 16 to 18, respectively.

[0144] In particular, it can be seen that the content of glass fiber is relatively low and the degree of curl is relatively large in Example 9. In contrast, it can be seen that the content of glass fiber is relatively high in Example 13 and the coating layer is not sufficiently cured by UV, making it difficult to measure the degree of curl. In such cases, it is deemed necessary to perform a secondary curing by performing an additional heat treatment.

[0145] Also, in the case of Examples 10 and 12, the content of monofunctional / difunctional acrylate was relatively high, and it was confirmed that the curl degree was relatively large compared to Examples 3 to 5.

[0146] Also, in the case of Example 11, the content of trifunctional acrylate was relatively high, and the adhesion between the coating layer and the current collector was insufficient, resulting in a relatively large degree of curling. In contrast, in the case of Example 14, the content of trifunctional acrylate was relatively low, and the degree of curling was relatively large compared to Examples 3 to 5.

[0147] As a result, when coating layers of the same thickness are included as in Examples 3 to 5 and Examples 9 to 14, the degree of curling of the single-sided positive electrodes including the coating layers of the compositions of Examples 3 to 5 may be relatively small, and it may be easier to stack them with other positive electrodes and negative electrodes in the electrode assembly unit.

[0148] Meanwhile, referring to Table 3, the thicknesses of the coating layers in Examples 15 to 20 are the same, but the compositions of the coating layers are different from each other, specifically, the weight ratios of the acrylate and the epoxy resin are different.

[0149] At this time, in the case of the single-sided positive electrodes having the compositions of Examples 15 and 16 in which the weight ratio of acrylate to epoxy resin is 4 to 5, the curl degree was measured to be -3 to -1 mm and -1 to 1 mm, respectively. That is, in the case of the single-sided positive electrodes having the coating layer compositions of Examples 15 and 16, the curl degree was relatively small.

[0150] In addition, in the case of the single-sided positive electrodes including the compositions of Examples 17 and 18 in which the content of the epoxy resin is smaller than that of the acrylate, the curl degree is −20 to −17 and −12 to −7, respectively, and it can be seen that the curl degree is relatively large.

[0151] In contrast, in the case of the single-sided positive electrodes including the compositions of Examples 19 and 20 in which the content of epoxy resin is higher than that of acrylate, the curl degree was 7 to 11 and 15 or more, respectively, and it was confirmed that the curl degree was relatively large, and there was a problem that the actual curing time was delayed.

[0152] Therefore, when acrylate and epoxy resin are used as the composition of the coating layer, it is preferable to mix the epoxy resin in a weight ratio of 4 to 5 times that of the acrylate.

[0153] Furthermore, in the case of Example 21, which contained only acrylate and was only irradiated with UV light, the curl was very large and cracks occurred in the coating layer, and in the case of Example 22, which contained only epoxy resin and was only heat treated, the curl was large and curing time was delayed, making it difficult to apply the roll-to-roll process and increasing the process time.

[0154] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also belong to the scope of the present invention. [Explanation of symbols]

[0155] 100: Positive electrode 101: Single-sided electrode (one side positive electrode or one side negative electrode) 110: Electrode current collector 150: Active material layer 180: Coating layer 102: Double-sided positive electrode 200: Double-sided negative electrode 300: Separation membrane 1000: Single-sided electrode manufacturing equipment 1100: Supply roller 1200: First coating device 1300: Roller 1500: Second coating device

Claims

1. Electrode current collector; an active material layer located on one surface of the electrode current collector; and a coating layer located on the other surface of the electrode current collector, the thickness of the coating layer is smaller than the thickness of the active material layer; The coating layer comprises: a) one or more acrylates selected from the group consisting of monofunctional acrylates, difunctional acrylates, and trifunctional acrylates; and b) a coating composition containing glass fibers or an epoxy-based resin; The coating layer is The trifunctional acrylate is present in an amount of 35% by weight or more and 69% by weight or less based on the total weight of the coating composition; The monofunctional acrylate and the difunctional acrylate are present in an amount of 20% by weight or more and 32% by weight or less based on the total weight of the coating composition; The coating composition includes glass fibers in an amount of 7 wt % to 20 wt % based on the total weight of the coating composition. Single-sided electrode.

2. Electrode current collector; an active material layer located on one surface of the electrode current collector; and a coating layer located on the other surface of the electrode current collector, the thickness of the coating layer is smaller than the thickness of the active material layer; The coating layer comprises: a) one or more acrylates selected from the group consisting of monofunctional acrylates, difunctional acrylates, and trifunctional acrylates; and b) a coating composition containing glass fibers or an epoxy-based resin; The coating layer is The trifunctional acrylate is present in an amount of 9% by weight or more and 20% by weight or less based on the total weight of the coating composition; The monofunctional acrylate is 5% by weight or more and 14% by weight or less based on the total weight of the coating composition; The epoxy resin is contained in a coating composition in an amount of 2 to 6 times the total amount of the trifunctional acrylate and the monofunctional acrylate. Single-sided electrode.

3. The single-sided electrode according to claim 1 , wherein the coating layer has a thickness that is 26% to 49% of the thickness of the active material layer.

4. The coating composition further comprises an initiator, and an additive; 10. The single-sided electrode of claim 1, wherein the initiator is a photoinitiator or a mixture of a photoinitiator and a thermal initiator.

5. The coating composition, The initiator is present in an amount of 1 wt % to 4 wt % based on the total weight of the coating composition, and the photoinitiator is present in an amount of 30 wt % to 100 wt % based on the total weight of the initiator. The single-sided electrode of claim 4 , wherein the additive is present in an amount of 0.1% by weight to 1% by weight based on the total weight of the coating composition.

6. The single-sided electrode according to claim 1 , wherein the curl degree of the single-sided electrode is from 0 mm to 5 mm.

7. An electrode current collector; an active material layer located on one surface of the electrode current collector; and a coating layer located on the other surface of the electrode current collector, the thickness of the coating layer is smaller than the thickness of the active material layer; The coating layer comprises: a) one or more acrylates selected from the group consisting of monofunctional acrylates, difunctional acrylates, and trifunctional acrylates; and b) a coating composition containing glass fibers or an epoxy-based resin; The coating layer is The trifunctional acrylate is present in an amount of 10% by weight or more and 14% by weight or less based on the total weight of the coating composition. The monofunctional acrylate is present in an amount of 5% by weight to 7% by weight based on the total weight of the coating composition. The epoxy resin is contained in a coating composition in an amount of 4 to 5 times the total amount of the trifunctional acrylate and the monofunctional acrylate. Single-sided electrode.

8. An electrode assembly comprising the single-sided electrode of any one of claims 1 to 7, The electrode assembly is formed by repeatedly stacking a double-sided positive electrode, a double-sided negative electrode, and a separator interposed between the double-sided positive electrode and the double-sided negative electrode, the single-sided electrode is disposed across the separator such that an active material layer of the single-sided electrode faces the double-sided negative electrode or the double-sided positive electrode located in at least one of the top and bottom layers of the electrode assembly; The double-sided positive electrode has a positive electrode active material layer disposed on both sides of a positive electrode current collector, The double-sided negative electrode is an electrode assembly in which negative electrode active material layers are disposed on both sides of a negative electrode current collector.

9. The electrode assembly according to claim 8 , wherein the single-sided electrode has a polarity opposite to that of the double-sided negative electrode or the double-sided positive electrode sandwiching the separator.

10. A single-sided electrode manufacturing apparatus for manufacturing the single-sided electrode according to any one of claims 1 to 7, a supply roller for supplying an electrode current collector; a first coating device that coats one surface of the electrode current collector with an active material composition to form an active material layer on the one surface of the electrode current collector; a second coating device that coats the other surface of the electrode current collector with a coating composition to form a coating layer on the other surface of the electrode current collector;

11. The single-sided electrode manufacturing apparatus according to claim 10 , further comprising: drying the electrode current collector on which the active material layer is formed and which is provided from the first coater.

12. The apparatus for manufacturing a single-sided electrode according to claim 11 , further comprising a pair of rolling rollers for rolling upper and lower surfaces of the electrode current collector on which the dried active material layer is formed.

13. The apparatus for manufacturing a single-sided electrode according to claim 10 , further comprising: irradiating ultraviolet (UV) rays to the coating layer of the electrode collector provided by the second coater for primary curing.

14. The ultraviolet (UV) irradiation dose is 0.5 J / cm ２ 1J / cm or more ２ 14. The single-sided electrode manufacturing apparatus according to claim 13, wherein:

15. The apparatus for manufacturing a single-sided electrode according to claim 13, further comprising a heat treatment device for performing a secondary curing by performing an additional heat treatment on the primarily cured coating layer.

16. The single-sided electrode manufacturing apparatus according to claim 15, wherein the additional heat treatment is carried out at 100 to 150° C. for 10 to 30 minutes.

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