Secondary battery and manufacturing method for secondary battery

Abstract

To provide a secondary battery and a manufacturing method for the secondary battery.SOLUTION: The present disclosure relates to a secondary battery and a manufacturing method for the secondary battery. A technical object to achieve is to provide a secondary battery in which a mixture is applied uniformly on an electrode plate, and a manufacturing method for the secondary battery. Therefore, the present disclosure provides a secondary battery including an electrode plate base material, a mixture part in which an outer side of the electrode plate base material is coated with a mixture including an active material, and a hydrophobic coating part that forms a coating layer including a hydrophobic substance on the electrode plate base material existing outside a border of the mixture part. The coating with the hydrophobic coating part is followed by the coating with the mixture part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a secondary battery and a method for manufacturing a secondary battery. [Background technology]

[0002] A secondary battery is a battery that can be charged and discharged, unlike a primary battery that cannot be charged. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and video cameras, while large-capacity secondary batteries are widely used as motor drive power sources and power storage batteries in hybrid vehicles, electric vehicles, and the like. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case that houses the electrode assembly, and an electrode terminal connected to the electrode assembly.

[0003] The above information disclosed in this Background of the Invention is intended to enhance the understanding of the background of the present invention and, therefore, may include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a secondary battery and a method for manufacturing the secondary battery in which a mixture can be applied uniformly to an electrode plate.

[0005] However, the technical problems that the present invention aims to solve are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0006] In order to solve the above technical problems, an exemplary secondary battery according to one embodiment of the present invention includes a plate substrate, a mixture portion in which an outer side of the plate substrate is coated with a mixture containing an active material, and a hydrophobic coating portion that forms a coating layer containing a hydrophobic material on the plate substrate located outside the boundary of the mixture portion.

[0007] As an example, the hydrophobic coating portion may be coated first, and then the combination portion may be coated.

[0008] As an example, the hydrophobic coating portion may be formed as a strip-shaped coating layer on both sides of the mixture portion in the width direction.

[0009] As an example, the hydrophobic coating may include a first material that includes at least one of nanosilica, fluorinated nanosilica, polyurethane, non-acetate silicone, and a fluorocarbon compound.

[0010] As an example, the hydrophobic coating may further include a second material used as a solvent mixed with the first material, the second material including ethanol.

[0011] As an example, the electrode plate substrate may be a negative electrode, and the mixture portion may include at least one of a conductive agent, a binder, an additive, and an active material.

[0012] As an example, the thickness of the hydrophobic coating portion may be the same as or less than the thickness of the combination portion.

[0013] As an example, the hydrophobic coating may be dried by a drying section using at least one of heat drying and ultraviolet drying.

[0014] An exemplary method for manufacturing a secondary battery according to an embodiment of the present invention includes a supplying step of supplying a plate substrate, a first coating step of coating a hydrophobic coating portion including a hydrophobic material on the plate substrate, and a second coating step of coating a mixture portion including an active material on the outside of the plate substrate after the first coating step.

[0015] As an example, the method may further include a drying step after the first coating step, in which a drying section operates to dry the hydrophobic coating section.

[0016] As an example, the drying step may include at least one of the following drying methods: heat drying and ultraviolet drying.

[0017] As an example, a correction step of correcting the coating shape of the hydrophobic coating portion may be further included between the first coating step and the drying step.

[0018] As an example, the first coating step may use a first material that includes at least one of nanosilica, fluorinated nanosilica, polyurethane, non-acetate silicone, and a fluorocarbon compound.

[0019] As an example, the first coating step may involve powdering a first material, mixing the first material with a second material used as a solvent to form a slurry, and then coating the slurry onto the electrode plate substrate.

[0020] As an example, a first coating step may involve applying an adhesive component to the plate substrate, followed by coating the slurry onto the plate substrate.

[0021] As an example, the first coating step may involve mixing an adhesive component into a slurry and then coating the slurry onto the electrode substrate. Effect of the Invention

[0022] According to the present invention, the provision of the hydrophobic coating portion prevents the mixture portion from spreading, and the mixture portion is provided uniformly, thereby improving the energy density.

[0023] In addition, the problem of insufficient amount of the mixture portion at the boundary of the mixture portion can be solved, and the charge / discharge performance of the secondary battery can be improved, thereby improving productivity.

[0024] However, the effects obtained through the present invention are not limited to the effects described above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0025] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to provide a better understanding of the technical concepts of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters depicted in such drawings. [Brief description of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view showing a positive electrode, a negative electrode, and a separator of a secondary battery according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front view showing an installation state of a coating module and a drying unit according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a perspective view showing an installation state of a coating module and a drying unit according to an embodiment of the present invention. [Figure 4] 2 is a plan view illustrating a state in which a hydrophobic coating portion and a mixture portion are formed on an electrode substrate according to an embodiment of the present invention; FIG. [Diagram 5] 4 is a cross-sectional view illustrating a state in which a hydrophobic coating portion and a mixture portion are formed on an electrode plate substrate according to an embodiment of the present invention. [Figure 6] 4 is a cross-sectional view illustrating a state in which a hydrophobic coating portion and a mixture portion are formed on an electrode plate substrate according to an embodiment of the present invention. [Figure 7] 4 is a cross-sectional view illustrating a state in which a hydrophobic coating portion and a mixture portion are formed on an electrode plate substrate according to an embodiment of the present invention. [Figure 8] FIG. 2 is a plan view showing a state in which a coating module and a drying unit are installed according to an embodiment of the present invention. [Figure 9] 4 is a plan view showing a state in which a guide unit is installed between a coating module and a drying unit according to an embodiment of the present invention. FIG. [Figure 10] 4 is a plan view illustrating a state in which a hydrophobic coating portion is aligned by a guide portion according to an embodiment of the present invention; FIG. [Figure 11] FIG. 11 is a perspective view showing a state in which a coating module according to another embodiment of the present invention is installed. [Figure 12]FIG. 4 is a perspective view showing a coating module according to another embodiment of the present invention. [Figure 13] 2 is a flowchart showing a method for manufacturing a secondary battery according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, the terms and words used in the present specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that match the technical idea of ​​the present invention based on the principle that the inventor can properly define the concept of the term in order to best describe his / her invention. Therefore, it should be understood that the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not fully represent the technical idea of ​​the present invention, and that there may be various equivalents and modifications that can replace them at the time of filing. In addition, as used in the present specification, "comprise" and / or "comprising" specify the presence of the mentioned shapes, numbers, steps, operations, members, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements, and / or groups. In addition, when describing an embodiment of the present invention, "can" and "may" may include one or more embodiments of the present invention.

[0028] In addition, in order to facilitate understanding of the present invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0029] A statement that two comparison objects are "identical" means that they are "substantially identical." Thus, "substantially identical" may include cases where there is a deviation that is considered to be a low level in the art, for example, a deviation within 5%. In addition, the uniformity of any parameter in a given region means that it is uniform from an average perspective.

[0030] Although the terms "first," "second," and the like are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and it goes without saying that a first component may also be a second component unless otherwise specified.

[0031] Throughout the specification, unless specifically stated to the contrary, each element may be singular or plural.

[0032] When an arbitrary structure is disposed on the top (or bottom) of a component or on (or below) a component, it does not only mean that the arbitrary structure is disposed in contact with the top surface (or bottom surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure disposed on (or below) the component.

[0033] In addition, when a certain component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components can be directly coupled or connected to each other, but different components may be "interposed" between each component, or each component may be "coupled," "coupled," or "connected" through another component. In addition, when a certain part is described as being electrically coupled to another part, this includes not only the case where they are directly coupled, but also the case where they are coupled via another element in between.

[0034] Throughout the specification, "A" and / or "B" means A, B, or A and B, unless specifically stated to the contrary. That is, "and / or" includes any and all combinations of the listed items. "C through D" means at least C, up to and including D, unless specifically stated to the contrary.

[0035] Hereinafter, a secondary battery 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG 1 is a cross-sectional view showing a positive electrode 50, a negative electrode 60, and a separator 40 of a secondary battery 1 according to an embodiment of the present invention. Referring to FIG 1, the secondary battery according to this embodiment may include at least one electrode assembly wound between a positive electrode 50 and a negative electrode 60 with a separator 40, which is an insulator, interposed therebetween. The secondary battery 1 may include a case in which the electrode assembly is housed, and a cap assembly coupled to an opening of the case.

[0036] The secondary battery according to the present embodiment will be described as a rectangular lithium ion secondary battery, but the present invention is not limited thereto, and may be applied to batteries of various shapes, such as a lithium polymer battery or a cylindrical battery.

[0037] The positive electrode 50 and the negative electrode 60 may include a coated portion, which is a region where an active material is applied to a current collector formed of a thin metal foil, and a plain portion, which is a region where the active material is not coated. In the present invention, the current collector of the negative electrode 60 may be called an electrode plate substrate 10, and the coated portion of the negative electrode 60 may be called a mixture portion 20.

[0038] The positive electrode 50 and the negative electrode 60 are wound with an insulating separator 40 interposed therebetween. However, the present invention is not limited thereto, and the electrode assembly may have a structure in which the positive electrode 50 and the negative electrode 60 made of a plurality of sheets are alternately stacked with the separator 40 interposed therebetween.

[0039] The case forms the overall appearance of the secondary battery and may be made of a conductive metal such as aluminum, an aluminum alloy, or nickel-plated steel, and may provide a space in which the electrode assembly is housed.

[0040] The cap assembly may include a cap plate that covers the opening of the case, and the case and the cap plate may be made of a conductive material. Here, the positive electrode 50 and negative electrode 60 terminals electrically connected to the positive electrode 50 and negative electrode 60 may be provided to protrude outward through the cap plate.

[0041] In addition, the outer circumferential surfaces of the upper posts of the positive electrode 50 and negative electrode 60 terminals protruding outside the cap plate may be threaded or fixed to the cap plate with nuts.

[0042] However, the present invention is not limited thereto, and the positive electrode 50 and negative electrode 60 terminals may be riveted to each other by a rivet structure, or may be welded to the cap plate.

[0043] The cap plate may be made of a thin plate and may be coupled to the opening of the case, and the cap plate may be formed with an electrolyte injection hole with a sealing plug and a vent portion with a notch. In one example, the vent portion may close a vent hole provided in the cap plate. In one example, the vent portion may be coupled or welded to a peripheral area (area of ​​the cap plate) of the vent hole.

[0044] Although the example described above is one in which the hydrophobic coating portion 30 is formed so that the installation area of ​​the mixture portion 20 of the negative electrode 60 is located within a set area, it goes without saying that the present invention is not limited to the negative electrode 60 and can also be applied to the coating portion of the positive electrode 50.

[0045] The mixture part 20, which is the coating part of the negative electrode 60, may be a slurry having fluidity. When the mixture part 20 is reduced due to abnormal process conditions and environment, the mixture part 20 of the negative electrode 60 facing the end of the coating part of the positive electrode 50 may be reduced. As a result, excess lithium ions (Li-ions) that are not accepted by the negative electrode 60 during charging form irreversible products and form an internal short circuit path with the positive electrode 50, which may cause a risk of fire. In order to reduce the risk of fire, a hydrophobic coating part 30 may be provided at the boundary of the mixture part 20 to prevent the amount of the mixture part 20 from being reduced.

[0046] At least one of the electrode plate substrate 10 of the negative electrode 60 and the positive electrode substrate 52 may be coated with a mixture containing an active material, a conductor, a binder, and an additive. The negative electrode mixture forms a mixture portion 20, and a positive electrode mixture 54 is formed on the positive electrode substrate 52. The mixture may be coated by various methods including a slot die type coating method.

[0047] The electrode plate substrate 10 according to an embodiment of the present invention is a current collector of the negative electrode 60, and the mixture portion 20 may include at least one of a conductive agent, a binder, an additive, and an active material.

[0048] The mixture part 20 can be modified in various ways within the technical concept of coating the outside of the electrode plate substrate 10 with a mixture containing an active material. The mixture part 20 may be a mixture slurry made of a solvent and powder. If the hydrophobic coating part 30 is not provided at the boundary of the slurry mixture part 20, the end of the mixture part 20 may flow and spread, resulting in a decrease in the thickness of the end of the mixture part 20 as intended in the design. In order to prevent a shortage of the amount of mixture applied at the end of the mixture part 20, the boundary of the mixture part 20 is coated with the hydrophobic coating part 30.

[0049] The negative electrode 60 slurry contains distilled water or water and has hydrophilic properties. Therefore, the hydrophobic coating portion 30, which is a hydrophobic material, may be applied to a position where the mixture portion 20, which is the negative electrode 60 slurry, is not coated or applied. When the hydrophobic coating portion 30 is applied to the electrode plate substrate 10 outside the boundary of the mixture portion 20, the negative electrode 60 mixture slurry, which has fluidity immediately after coating the mixture portion 20, forms a high contact angle at the coating edge portion. Since the hydrophilic mixture portion 20 is restricted from moving beyond the hydrophobic coating portion 30 by the hydrophobic coating portion 30, the phenomenon of the thickness of the mixture portion 20 decreasing even at the end of the mixture portion 20 can be minimized.

[0050] FIG. 2 is a front view showing the installation state of the coating module 160 and the drying unit 170 according to an embodiment of the present invention, and FIG. 3 is a perspective view showing the installation state of the coating module 160 and the drying unit 170 according to an embodiment of the present invention. As shown in FIG. 2 and FIG. 3, the hydrophobic coating unit 30 can be modified in various ways within the technical idea of ​​forming a coating layer containing a hydrophobic material on the electrode plate substrate 10 located outside the boundary of the mixture unit 20. The hydrophobic coating unit 30 can be provided to reduce the deviation in width of the mixture unit 20. The spreading phenomenon of the mixture unit 20 affects the increase in width and dispersion of the mixture unit 20. The application of the hydrophobic coating unit 30 containing a hydrophobic material suppresses the spreading of the mixture unit 20, which is the negative electrode 60 slurry that has been managed only by the solid content and viscosity of the negative electrode 60 mixture slurry, and can uniform the width of the mixture unit 20, thereby affecting the improvement of dispersion.

[0051] In the electrode plate substrate 10 of the negative electrode 60, a hydrophobic coating portion 30 is coated or applied to the boundary of the mixture portion 20. The hydrophobic coating portion 30 may be applied linearly in the running direction or longitudinal direction D of the electrode plate substrate 10. The provision of the hydrophobic coating portion 30 can prevent a phenomenon in which the aqueous (hydrophilic) negative electrode 60 mixture slurry spreads outside the designed coating area, resulting in a reduction in the amount of the mixture portion 20.

[0052] After the hydrophobic coating portion 30 is coated, the mixture portion 20 may be coated. The hydrophobic coating portion 30 may form a strip-shaped coating layer on both sides of the mixture portion 20 in the width direction W. The hydrophobic coating portion 30 may be coated or applied in a strip shape extending in the longitudinal direction D of the electrode plate substrate 10. The longitudinal direction D of the electrode plate substrate 10 may be the same as the moving direction of the electrode plate substrate 10. The width direction W and the longitudinal direction D may form a right angle.

[0053] The hydrophobic material contained in the hydrophobic coating portion 30 must have stable properties that do not participate in the electrochemical reaction in the secondary battery 1. The hydrophobic coating portion 30 according to an embodiment of the present invention may include a first material including at least one of nanosilica, fluorinated nanosilica, polyurethane, non-acetate silicone, and a fluorocarbon compound.

[0054] The electrode plate substrate 10 of the negative electrode 60 may contain Cu. In order to apply the hydrophobic coating portion 30 to the electrode plate substrate 10, a pretreatment may be applied in which a powdered hydrophobic material is mixed with a solvent such as ethanol to form a slurry. In this case, since the slurried hydrophobic material may adversely affect the coating quality of the slurry, which is the mixture portion 20, a separate drying process may be added.

[0055] The application of the slurried hydrophobic material may be performed by a slot die method in the same manner as the coating of the slurried mixture part 20. A coating module 160 that discharges the slurry may be operated only when there is movement of the electrode plate substrate 10. Therefore, since the coating module 160 does not operate when the movement of the electrode plate substrate 10 is stopped, it is possible to prevent the hydrophobic material from being excessively applied to the electrode plate substrate 10.

[0056] The hydrophobic coating portion 30 according to an embodiment of the present invention may further include a second material including ethanol, which is used as a solvent mixed with the first material. The first material includes the hydrophobic material as described above.

[0057] To form the mixture part 20, the electrode plate substrate 10 must be coated with the negative electrode 60 slurry. The negative electrode 60 slurry, which includes a liquid, can be solidified to form the mixture part 20. The electrode plate substrate 10 can pass through multiple rollers to maintain a constant tension.

[0058] After passing through the pair of first rollers 100, the electrode plate substrate 10 may pass through a second roller 110 that functions as a backup roll to maintain tension. A coating module 160 and a drying section 170 may be provided between the first roller 100 and the second roller 110. The coating module 160 and the drying section 170 may be provided at positions facing the moving path of the electrode plate substrate 10.

[0059] The hydrophobic material discharged from the coating module 160 is applied and attached to the electrode plate substrate 10 to form the hydrophobic coating portion 30. The application and attachment of the hydrophobic material may be performed when or before the electrode plate substrate 10 passes through the second roller 110 functioning as a backup roll. The upper surface (see FIG. 2) of the electrode plate substrate 10 may be coated with the hydrophobic material, and then the mixture portion 20 may be coated. If the upper and lower surfaces of the electrode plate substrate 10 are simultaneously coated with the hydrophobic material and the mixture slurry, problems may occur such as the electrode plate substrate 10 contaminating the rollers as it passes through multiple rollers, and the shape of the hydrophobic coating portion 30 may be deformed. Therefore, only the upper surface of the electrode plate substrate 10 that does not contact the rollers may be coated with the hydrophobic material and the mixture slurry first, and then the opposite surface of the electrode plate substrate 10 may be coated with the hydrophobic material and the mixture slurry in a subsequent process.

[0060] A mixture supplying unit 120 that discharges a mixture slurry may be provided on a side surface of the second roller 110 that functions as a backup roll. The mixture supplying unit 120 may be modified in various ways within the technical concept of forming the mixture unit 20 by supplying the mixture slurry to the electrode plate substrate 10. The mixture supplying unit 120 according to an embodiment of the present invention may include a supply head 130, a connecting pipe 140, and a control valve 150.

[0061] The supply head 130 is provided at a position facing the second roller 110. The supply head 130 supplies the mixture slurry to the outer surface of the electrode plate substrate 10 moving along the outer surface of the second roller 110. The supply head 130 according to an embodiment of the present invention may include a head body 132 provided at a position facing the second roller 110, and an inner tank 134 located inside the head body 132 and storing the mixture slurry supplied through the connecting pipe 140. The supply head 130 includes an inner pipe 136 extending from the inner tank 134 in a direction toward the second roller 110.

[0062] The connecting pipe 140 extends inside the head body 132 and is connected to the inner tank 134. The amount of the mixture slurry passing through the connecting pipe 140 may be adjusted by the operation of a control valve 150 connected to the connecting pipe 140. The inner tank 134 forms a space for storing the mixture slurry inside the head body 132. The mixture slurry stored in the inner tank 134 may be transferred through an inner pipe 136 communicating with the inner tank 134 and then applied to the outside of the electrode plate substrate 10.

[0063] The coating module 160 is provided between the first roller 100 and the second roller 110, and may be provided on the upper side of the electrode plate substrate 10 moving from the first roller 100 to the second roller 110. The coating module 160 may be supplied with hydrophobic slurry and apply it to the upper side of the electrode plate substrate 10 to form a hydrophobic coating unit 30. The configuration of the coating module 160 may be the same as that of the mixture supply unit 120, and therefore a detailed configuration of the coating module 160 will be omitted.

[0064] In order to dry the hydrophobic slurry discharged from the coating module 160, a drying section 170 may be provided at a position facing the electrode plate substrate 10 that has passed through the coating module 160. The drying section 170 may form the hydrophobic coating section 30 by drying the hydrophobic slurry using at least one of thermal drying and ultraviolet drying.

[0065] The coating modules 160 may be provided on both sides of the width direction W of the electrode plate substrate 10. The drying units 170 may also be provided on both sides of the width direction W of the electrode plate substrate 10. The drying unit 170 may be provided on the rear side of the longitudinal direction (traveling direction) D of the electrode plate substrate 10 based on the coating module 160. Therefore, the slurry containing the hydrophobic material discharged from the coating module 160 to the electrode plate substrate 10 is dried by the drying unit 170 and does not contaminate rollers in a subsequent process.

[0066] 4 is a plan view showing a state in which a hydrophobic coating portion 30 and a mixture portion 20 are formed on an electrode plate substrate 10 according to an embodiment of the present invention. As shown in Fig. 4, strip-shaped hydrophobic coating portions 30 extending in a longitudinal direction D are located on both sides of a width direction W of the electrode plate substrate 10. The hydrophobic coating portions 30 and the ends of the electrode plate substrate 10 are spaced apart at a set interval to form uncoated portions.

[0067] The hydrophobic coating portion 30 is provided on both sides of the mixture portion 20 in the width direction W. First, the hydrophobic coating portion 30 is coated, and then a mixture slurry for making the mixture portion 20 is applied to the electrode plate substrate 10. The mixture slurry having fluidity is provided only in the area defined by the hydrophobic coating portion 30.

[0068] 5 to 7 are cross-sectional views showing a state in which a hydrophobic coating portion 30 and a mixture portion 20 are formed on an electrode plate substrate 10 according to an embodiment of the present invention. As shown in Fig. 5, the shape and end contact angle of the mixture slurry of the negative electrode 60 can be adjusted depending on the application thickness or coating thickness of the hydrophobic coating portion 30, so that the end contact angle and shape of the mixture portion 20 can be adjusted. Since the shape of the mixture portion 20 can be controlled, the charge and discharge performance of the secondary battery 1 can be optimized.

[0069] The hydrophobic material used in the hydrophobic coating portion 30 has a stability such that it is not involved in the electrochemical reaction in the secondary battery 1, and therefore the stability of the secondary battery 1 can be maintained.

[0070] The coating thickness of the hydrophobic coating portion 30 must be lower than the coating height of the mixture slurry having flowing properties, and is preferably similar to the target height of the mixture portion 20 in the rolling process. If the hydrophobic coating portion 30 is applied thicker than the mixture slurry of the anode 60, the hydrophobic coating portion 30 is compressed by the rolling rollers to cover the upper side of the mixture portion 20, which may hinder the movement of lithium ions (Li-ions) during charging and discharging operations, thereby degrading charge and discharge performance. The thickness of the hydrophobic coating portion 30 according to an embodiment of the present invention may be the same as or smaller than the thickness of the mixture portion 20.

[0071] The shapes of both side ends of the mixture portion 20 in the width direction W may be changed according to the height of the hydrophobic coating portion 30. When the height of the hydrophobic coating portion 30 is 20% or less than the height of the mixture portion 20, the contact angle of the mixture portion 20 becomes high. The contact angle is the angle between the inclined surfaces of the width direction (W) ends of the mixture portion 20 and the electrode plate substrate 10.

[0072] As shown in Fig. 6, when the height of the hydrophobic coating portion 31 is increased, the contact angle of the mixture portion 20 decreases. When the height of the hydrophobic coating portion 32 is increased to a height slightly lower than the height of the mixture portion 20, as shown in Fig. 7, the contact angle of the mixture portion 20 may become lower than the previous contact angle. The shape of the mixture slurry at the coating edge portion of the electrode plate substrate 10 is determined by the contact angle formed between the slurry and the electrode plate substrate 10.

[0073] 8 is a plan view showing a state in which a coating module 160 and a drying unit 170 are installed according to an embodiment of the present invention. As shown in Fig. 8, the hydrophobic coating unit 30 may be dried by the drying unit 170 using at least one of heat drying and ultraviolet drying. Assuming that the electrode plate substrate 10 moves toward the upper side in the longitudinal direction D (see Fig. 8), the drying unit 170 may be installed on the upper side of the longitudinal direction D of the coating module 160.

[0074] FIG. 9 is a plan view showing a state where a guide unit 180 is provided between a coating module 160 and a drying unit 170 according to an embodiment of the present invention, and FIG. 10 is a plan view showing a state where a hydrophobic coating unit 30 is aligned by a guide unit 180 according to an embodiment of the present invention. As shown in FIGS. 9 and 10, the shape of the hydrophobic slurry sprayed from the coating module 160 may not be linear. Therefore, the guide unit 180 may be provided between the coating module 160 and the drying unit 170 to correct the shape of the hydrophobic coating unit 30. The guide unit 180 may be provided to improve the phenomenon that the hydrophobic material applied to the hydrophobic coating unit 30 in the form of hydrophobic slurry or the component of the adhesive applied to the upper side of the electrode plate substrate of the negative electrode 60 is applied non-uniformly and the boundary becomes unclear.

[0075] The guide unit 180 according to an embodiment of the present invention includes a first guide 182 provided on one side in the width direction W facing the moving path of the hydrophobic coating unit 30, and a second guide 184 provided at a position facing the first guide 182 across the hydrophobic coating unit 30. The hydrophobic coating unit 30 is located between the first guide 182 and the second guide 184, and the inlets and outlets of the first guide 182 and the second guide 184 are provided in a state spaced apart from each other. The guide unit 180 is provided in a fixed state together with the coating module 160. The length L1 of the inlet width of the first guide 182 and the second guide 184 is greater than the length L2 of the outlet width. Since the entrance of the guide part 180 is larger than the exit, the hydrophobic coating part 30 moving through the entrance of the guide part 180 to the exit of the guide part 180 has the same width as the exit width of the guide part 180, and the shape of the hydrophobic coating part 30 is corrected to a straight line extending in the longitudinal direction D.

[0076] According to the present invention as described above, the spread of the mixture part 20 is prevented by providing the hydrophobic coating part 30, and the mixture part 20 is provided uniformly, thereby improving the energy density. In addition, the problem of insufficient amount of the mixture part 20 at the boundary of the mixture part 20 is solved, and the charge / discharge performance of the secondary battery 1 and the productivity can be improved.

[0077] 13 is a flowchart showing a method for manufacturing a secondary battery 1 according to an embodiment of the present invention. As shown in FIG. 13, the method for manufacturing an exemplary secondary battery 1 according to an embodiment of the present invention includes a supply step S10 of supplying an electrode plate substrate 10. The electrode plate substrate 10 may be moved through a first roller 100 and a second roller 110.

[0078] After the supply step, the electrode plate substrate 10 is coated with a hydrophobic coating portion 30 including a hydrophobic material in a first coating step S20. The first coating step S20 may use a first material including at least one of nanosilica, fluorinated nanosilica, polyurethane, non-acetate silicon, and a fluorocarbon compound. The first coating step S20 may include powdering the first material, mixing the first material with a second material used as a solvent to form a slurry, and then coating the slurry on the electrode plate substrate 10.

[0079] In the first coating step S20, an adhesive component may be applied to the electrode plate substrate 10, and then the slurry may be coated onto the electrode plate substrate 10. As the adhesive, a polymer adhesive such as polyurethane, polyacrylate, or epoxy resin may be used.

[0080] In the first coating step S20, an adhesive component may be mixed into the slurry, and then the slurry may be coated onto the electrode plate substrate 10. A polymer adhesive may be used as the adhesive. The hydrophobic material may be applied by applying an adhesive component onto the electrode plate substrate 10, and then attaching a powdered hydrophobic material to the adhesive component to form the hydrophobic coating portion 30.

[0081] Alternatively, the hydrophobic material in a mixed state of the adhesive component and the powdered hydrophobic material may be applied onto the electrode plate substrate 10 by a slot die method.

[0082] A correction step of correcting the coating shape of the hydrophobic coating unit 30 may be further included between the first coating step S20 and the drying step. The hydrophobic coating unit 30 discharged from the coating module 160 and applied to the electrode plate substrate 10 may pass through a guide unit 180 including a first guide 182 and a second guide 184 to have its shape corrected.

[0083] After the first coating step S20, the method may further include a drying step S40 in which a drying unit 170 operates to dry the hydrophobic coating unit 30. The drying step S40 may include at least one drying method of heat drying and ultraviolet drying. The hydrophobic coating unit 30 that has passed through the guide unit 180 or that has been applied in the coating module 160 passes through the drying unit 170 and is dried.

[0084] After the first coating step S20, a second coating step S50 is included in which a mixture part 20 containing an active material is coated on the outside of the electrode plate substrate 10. After drying of the hydrophobic coating part 30 is completed, a mixture slurry is applied to the electrode plate substrate 10 via a mixture supply part 120 to form the mixture part 20. The mixture part 20 does not invade the area of ​​the hydrophobic coating part 30, and the shape of the end of the mixture part 20 may be controlled according to the height of the hydrophobic coating part 30.

[0085] 11 is a perspective view showing a state where a coating module 260 according to another embodiment of the present invention is installed, and FIG. 12 is a perspective view showing the coating module 260 according to another embodiment of the present invention. As shown in FIG. 11 and FIG. 12, the coating module 260 according to another embodiment of the present invention can be modified in various ways within the technical idea of ​​applying a hydrophobic slurry and a material of a pressure sensitive adhesive or adhesive component to the electrode plate substrate 10. The coating module 260 according to another embodiment of the present invention may include a first coating head 262, a first pipe 264, a first tank 266, a first spray nozzle 268, a second coating head 272, a second pipe 274, a second tank 276, and a second spray nozzle 278. The main body of the coating module 260 includes the first coating head 262 and the second coating head 272.

[0086] A first tank 266 for storing hydrophobic slurry is provided inside the first coating head 262. The hydrophobic slurry is transferred to the first tank 266 through a first pipe 264 connected to the first tank 266. A first injection nozzle 268 extending from the first tank 266 extends from the first tank 266 to an outlet of the first coating head 262. Therefore, the hydrophobic slurry transferred from the first tank 266 to the first injection nozzle 268 is discharged toward the electrode plate substrate 10.

[0087] A second tank 276 for storing an adhesive or adhesive component material is provided inside the second coating head 272 facing the first coating head 262. The adhesive or adhesive component material is transferred to the second tank 276 through a second pipe 274 connected to the second tank 276. A second spray nozzle 278 extending from the second tank 276 extends from the second tank 276 to an outlet of the second coating head 272. Therefore, the adhesive or adhesive component material transferred from the second tank 276 to the second spray nozzle 278 is discharged toward the electrode plate substrate 10.

[0088] After applying an adhesive or pressure-sensitive adhesive component to the electrode plate substrate 10 through the second spray nozzle 278 to form an adhesive layer 300, the electrode plate substrate 10 may be coated with a hydrophobic slurry through the first spray nozzle 268 to form a hydrophobic coating portion 30. The adhesive or pressure-sensitive adhesive may be a polymer adhesive such as polyurethane, polyacrylate, or epoxy resin.

[0089] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is of course possible for a person having ordinary skill in the art to which the present invention pertains to make various modifications and variations within the technical spirit of the present invention and the equivalent scope of the claims described below. [Explanation of symbols]

[0090] 1: Secondary battery 10: Plate base material 20: Combination drug section 30, 31, 32: Hydrophobic coating section 40: Separator 50: Positive electrode 52: Positive substrate 54: Positive electrode mixture 60: Negative electrode 100: First Roller 110: The second roller 120: Combination drug supply unit 130: Supply head 132: Head body 134: Inner tank 136:Inner duct 140: Connecting pipe 150: Control valve 160: Coating module 170:Drying section 180: Guide section 182: First Guide 184: Second Guide 260: Coating module 262: First coating head 264: First Pipeline 266: First Tank 268: First jet nozzle 272: Second coating head 274: Second Pipeline 276: Second Tank 278: Second injection nozzle 300: Adhesive layer L1: Length of entrance width L2: Length of the outlet width W: Width direction D: Length direction S10: Supply stage S20: First coating stage S30: Orthodontic stage S40: Drying stage S50: Second coating stage

Claims

1. electrode plate base material, A mixture portion in which a mixture containing an active material is coated on the outside of the electrode plate substrate; and The electrode substrate includes a hydrophobic coating portion located outside the boundary of the mixture portion, the hydrophobic coating portion being a coating layer including a hydrophobic material, The secondary battery, wherein the mixture portion is coated after the hydrophobic coating portion is coated.

2. The secondary battery according to claim 1 , wherein the hydrophobic coating portion forms a strip-shaped coating layer on both sides of the mixture portion in a width direction.

3. 2. The secondary battery according to claim 1, wherein the hydrophobic coating portion includes a first material including at least one of nanosilica, fluorinated nanosilica, polyurethane, non-acetate silicone, and a fluorocarbon compound.

4. The secondary battery according to claim 3 , wherein the hydrophobic coating further comprises a second material, the second material being used as a solvent mixed with the first material and including ethanol.

5. The secondary battery according to claim 1 , wherein the electrode plate substrate is a negative electrode, and the mixture portion contains at least one of a conductive agent, a binder, an additive, and the active material.

6. The secondary battery according to claim 1 , wherein the thickness of the hydrophobic coating portion is equal to or smaller than the thickness of the mixture portion.

7. The secondary battery according to claim 1 , wherein the hydrophobic coating is dried by a drying unit that uses at least one of heat drying and ultraviolet drying.

8. a supplying step of supplying a plate substrate; A first coating step of coating the electrode substrate with a hydrophobic coating portion including a hydrophobic material; and The method for producing a secondary battery further comprises a second coating step of coating an outer surface of the electrode plate substrate with a mixture portion containing an active material after the first coating step.

9. The method of claim 8, further comprising, after the first coating step, a drying step of operating a drying unit to dry the hydrophobic coating portion.

10. The method of claim 9, wherein the drying step includes at least one of thermal drying and ultraviolet drying.

11. The method of claim 9, further comprising a step of correcting a coating shape of the hydrophobic coating portion between the first coating step and the drying step.

12. 9. The method for manufacturing a secondary battery according to claim 8, wherein the first coating step uses a first material including at least one of nanosilica, fluorinated nanosilica, polyurethane, non-acetate silicone, and a fluorocarbon compound.

13. The first coating step includes powdering the first material; After mixing the first material with a second material used as a solvent to form a slurry, The method for producing a secondary battery according to claim 12, further comprising coating the electrode plate substrate with the slurry.

14. The method of claim 13, wherein the first coating step comprises coating the electrode plate substrate with an adhesive component and then coating the electrode plate substrate with the slurry.

15. The method of claim 13, wherein the first coating step comprises mixing the slurry with an adhesive component and then coating the slurry on the electrode plate substrate.

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