Electrode for multifunctional structural batteries having planar heating and load-bearing capabilities, Method for manufacturing the same, and structural battery Including the same

Abstract

A method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to the present invention may include the steps of: preparing a substrate; providing a first metal nanoparticle containing Fe on the substrate to form a first metal layer; providing a second metal nanoparticle containing Al on the first metal layer to form a second metal layer thicker than the first metal layer; providing a carbon source on the second metal layer to form a carbon nanotube layer; and printing a heating paste containing carbon nanotubes and graphite on the carbon nanotube layer to form a heating layer.

Description

Technology Field

[0001] The present invention relates to an electrode for a multi-purpose multi-functional structural battery having a planar heating function and a load-bearing function, a method for manufacturing the same, and a structural battery including the same. More specifically, the invention relates to an electrode for a multi-purpose multi-functional structural battery having a first metal layer, a second metal layer, a carbon nanotube layer, and a heating layer formed on a substrate, a method for manufacturing the same, and a structural battery including the same. Background Technology

[0002] As applications requiring both lightweighting and high energy density are rapidly increasing, such as electric vehicles, unmanned aerial vehicles, aerospace structures, wearable robots, and smart mobility, multi-functional structural battery technology that performs both energy storage and mechanical load-bearing functions is attracting attention.

[0003] Conventional secondary batteries are independent components for electrical energy storage and do not support structural loads, so separate mechanical structural materials are necessarily required within the product.

[0004] Such structural separation leads to increased overall system weight and limited internal space utilization, while the addition of battery protection cases and fixing structures results in increased dead weight. Consequently, there is a growing technical demand to simultaneously improve lightweighting and energy density by integrating electrical and structural functions into a single composite structure.

[0005] In accordance with this need, structural batteries are defined as next-generation secondary battery technology designed to maintain energy storage functionality while securing mechanical rigidity by integrating electrodes, electrolytes, conductive current collectors, and composite matrices into a single structural element.

[0006] Carbon fiber composite-based structural batteries are being proposed for use in various industrial fields, such as aircraft skin panels, drone frames, vehicle bodies, and robot structural materials, due to their high tensile strength, low density, and excellent electrical properties. However, conventional structural battery electrodes struggle to simultaneously satisfy both structural strength and electrochemical performance requirements, and there is a problem of rapid performance degradation caused by mechanical and electrical instability occurring at the interface between the electrode and the solid / semi-solid electrolyte. In particular, the accumulation of expansion / contraction deformation during repeated charge / discharge processes, residual stress within the composite, and micro-delamination between the electrolyte and the electrode layer severely impacts the reliability and lifespan of the structural battery.

[0007] Meanwhile, structural batteries are significantly exposed to temperature changes depending on the operating environment; under low-temperature conditions, ionic conductivity decreases sharply and internal resistance increases, leading to a significant decline in charge / discharge efficiency. Additionally, there are issues where the brittleness of composite materials increases at low temperatures, and repetitive loading causes greater mechanical fatigue. Despite these problems, existing research on structural batteries has focused on securing electrochemical performance and structural rigidity, and structural battery electrode technologies equipped with planar heating functions to actively control the internal temperature of the battery have rarely been proposed.

[0008] Conventional CNT (Graphite / MWCNT)-based planar heating elements are utilized in electronic devices or wearable products in the form of films or coatings. However, in environments where high compressive stress, shear stress, and bending load are repeatedly applied, such as in structural batteries, problems such as interfacial delamination, increased resistance, non-uniform heating patterns, and temperature variations are prone to occur. In other words, there are technical limitations in that conventional planar heating elements lack sufficient mechanical durability and interfacial stability to be directly introduced into structural batteries.

[0009] Against this backdrop, there is a significant technical need for a new type of multifunctional electrode for structural batteries that can operate stably within the battery while simultaneously supporting structural loads, control local temperature variations through planar heating functions, and simultaneously improve electrical, mechanical, and thermal properties by optimizing CNT-based electrode layers, graphite / CNT composite heating layers, binder / solvent composition designs, and interfacial adhesion structures. The problem to be solved

[0010] The technical problem that the present invention aims to solve is to provide an electrode for a multi-purpose multi-functional structural battery that simultaneously possesses a load-bearing function and a heating function.

[0011] Another technical problem that the present invention aims to solve is to provide an electrode for a multi-purpose multi-functional structural battery with improved conductivity and mechanical stability.

[0012] Another technical problem that the present invention aims to solve is to provide a method for manufacturing an electrode for a multi-purpose multi-functional structural battery with reduced manufacturing process costs.

[0013] Another technical problem that the present invention aims to solve is to provide a method for manufacturing an electrode for a multi-purpose multi-functional structural battery with reduced manufacturing time.

[0014] Another technical problem that the present invention aims to solve is to provide a method for manufacturing an electrode for a multi-purpose multi-functional structural battery that is easy to mass-produce.

[0015] The technical problems that the present invention aims to solve are not limited to those described above. means of solving the problem

[0016] To solve the above technical problem, the present invention provides a method for manufacturing an electrode for a multi-purpose multi-functional structural battery.

[0017] According to one embodiment, a method for manufacturing an electrode for a multi-purpose multi-functional structural battery may include the steps of: preparing a substrate; providing a first metal nanoparticle containing Fe on the substrate to form a first metal layer; providing a second metal nanoparticle containing Al on the first metal layer to form a second metal layer thicker than the first metal layer; providing a carbon source on the second metal layer to form a carbon nanotube layer; and printing a heating paste containing carbon nanotubes and graphite on the carbon nanotube layer to form a heating layer.

[0018] According to one embodiment, the step of manufacturing the heating paste may include the step of preparing a first solution by mixing the carbon nanotube, the graphite, a dispersant, and a first solvent; the step of preparing a second solution by mixing a thermoplastic binder and a second solvent; and the step of manufacturing the heating paste by mixing the first solution and the second solution.

[0019] To solve the above technical problem, the present invention provides an electrode for a multi-purpose multi-functional structural battery manufactured by the manufacturing method described above.

[0020] According to one embodiment, the electrode for a multi-purpose multi-functional structural battery may comprise a substrate, a first metal layer having first metal nanoparticles containing Fe on the substrate, a second metal layer thicker than the first metal layer having second metal nanoparticles containing Al on the first metal layer, a carbon nanotube layer on the second metal layer, and a heating layer including carbon nanotubes and graphite on the carbon nanotube layer. Effects of the invention

[0021] A method for manufacturing an electrode for a multi-functional multi-purpose structured battery according to the present invention may include the steps of: preparing a substrate; providing a first metal nanoparticle containing Fe on the substrate to form a first metal layer; providing a second metal nanoparticle containing Al on the first metal layer to form a second metal layer thicker than the first metal layer; providing a carbon source on the second metal layer to form a carbon nanotube layer; and coating a heating paste containing carbon nanotubes and graphite on the carbon nanotube layer to form a heating layer.

[0022] In the step of forming the carbon nanotube layer, the first metal layer performs a catalytic function for the growth of carbon nanotubes from the carbon source, and the second metal layer, which is thicker than the first metal layer, can perform a buffer function to promote the longitudinal and vertical growth of the carbon nanotubes. Accordingly, a plurality of carbon nanotubes can be easily generated and grown on a metal layer comprising the first metal layer and the second metal layer. Accordingly, the carbon nanotube layer comprising a plurality of carbon nanotubes grown in a vertically aligned manner can be easily formed. Furthermore, adhesion and interfacial stability can be improved at the interface between the substrate and the first metal layer, the interface between the first metal layer and the second metal layer, and the interface between the second metal layer and the carbon nanotube layer. As a result, due to the synergistic effect of the first metal layer, the second metal layer, and the carbon nanotube layer on the substrate, the mechanical and electrical performance of the electrode for a multi-purpose multi-functional structural battery can be improved.

[0023] And, the step of manufacturing the heating paste may include the step of preparing a first solution by mixing carbon nanotubes, graphite, a dispersant, and a first solvent; the step of preparing a second solution by mixing a thermoplastic binder and a second solvent; and the step of manufacturing the heating paste by mixing the first solution and the second solution.

[0024] In the step of preparing the first solution, a solvent of the Caprylyl acetate series may be used as the first solvent. Accordingly, the π-π interaction between the carbon nanotube and the graphite can be maintained. As a result, the carbon nanotube and the graphite can be maintained in a stable, long-term dispersed state within the first solution without aggregation.

[0025] In addition, in the step of preparing the second solution, the thermoplastic binder may be a thermoplastic polyurethane. Accordingly, leveling stability in the screen printing process is improved, thereby enhancing the stability of the heating layer and, furthermore, the stability against mechanical stress applied during the operation of the structured battery to which the electrode is applied. Additionally, as the second solvent, a mixed solvent comprising methyl ethyl ketone (MEK) and N,N-dimethylformamide (DMF) may be used. Accordingly, the solubility of the thermoplastic polyurethane (TPU), which is the thermoplastic binder, is improved, and the drying speed of the heating paste can be optimized. Accordingly, the rheology for the screen printing process of the heating paste is optimized, thereby forming a heating layer with improved stability.

[0026] Accordingly, the electrode for a multi-purpose multi-functional structural battery manufactured by the method described above may include the first metal layer, the second metal layer, the carbon nanotube layer, and the heating layer on the substrate.

[0027] The substrate can perform the function of supporting the load of the structural battery to which the electrode is applied. Furthermore, since the carbon nanotubes within the carbon nanotube layer are vertically aligned due to the substrate, the first metal layer, and the second metal layer, the mechanical stability and conductivity of the electrode can be improved. Additionally, conductivity and heating performance can be improved due to the carbon nanotube layer and the heating layer. Accordingly, the mechanical strength, conductivity, and heating performance of the structural battery to which the electrode is applied can be simultaneously improved. Brief explanation of the drawing

[0028] FIG. 1 is a flowchart illustrating a method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to an embodiment of the present invention. FIG. 2 is a drawing for explaining the step of preparing a substrate according to an embodiment of the present invention. FIG. 3 is a drawing for explaining the step of forming a first metal layer according to an embodiment of the present invention. FIG. 4 is a drawing for explaining the step of forming a second metal layer according to an embodiment of the present invention. FIG. 5 is a diagram illustrating the step of forming a carbon nanotube layer according to an embodiment of the present invention. FIG. 6 is a flowchart illustrating a method for manufacturing a heating paste according to an embodiment of the present invention. FIG. 7 is a drawing for explaining the step of preparing a first solution according to an embodiment of the present invention. FIG. 8 is a drawing for explaining the step of preparing a second solution according to an embodiment of the present invention. FIG. 9 is a drawing for explaining the steps of manufacturing a heating paste according to an embodiment of the present invention. FIG. 10 is a drawing for explaining the step of forming a heating layer according to an embodiment of the present invention. FIG. 11 is a drawing illustrating the step of surface treating a carbon nanotube layer according to a first modified example of the present invention. FIG. 12 is a drawing for explaining the step of forming a primer layer according to a first modified example of the present invention. FIG. 13 is a drawing for explaining the step of forming a heating layer according to a first modified example of the present invention. FIG. 14 is a drawing for explaining a structure in which a first metal layer, a second metal layer, and a carbon nanotube layer are formed on a substrate according to a second modified example of the present invention. FIG. 15 is a drawing for explaining the step of forming a first heating layer according to a second modified example of the present invention. FIG. 16 is a drawing for explaining the step of forming a second heating layer according to a second modified example of the present invention. Specific details for implementing the invention

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete and to ensure that the concept of the present invention is sufficiently conveyed to those skilled in the art.

[0030] In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, the thicknesses of the films and regions are exaggerated for the effective description of the technical content.

[0031] Additionally, although terms such as first, second, third, etc., have been used to describe various components in the various embodiments of this specification, these components should not be limited by such terms. These terms are used merely to distinguish one component from another. Accordingly, what is referred to as the first component in one embodiment may be referred to as the second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. Furthermore, in this specification, "and / or" is used to mean including at least one of the components listed before and after it.

[0032] In the specification, singular expressions include plural expressions unless the context clearly indicates otherwise. Furthermore, terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, components, or combinations thereof described in the specification, and should not be understood as excluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. Additionally, in this specification, "connection" is used to include both indirectly connecting multiple components and directly connecting them.

[0033] In addition, in describing the present invention below, if it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the invention, such detailed description will be omitted.

[0035] Electrode for a multi-purpose multi-functional structural battery according to an embodiment of the present invention

[0036] FIG. 1 is a flowchart for explaining a method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to an embodiment of the present invention, FIG. 2 is a diagram for explaining a step of preparing a substrate according to an embodiment of the present invention, FIG. 3 is a diagram for explaining a step of forming a first metal layer according to an embodiment of the present invention, FIG. 4 is a diagram for explaining a step of forming a second metal layer according to an embodiment of the present invention, FIG. 5 is a diagram for explaining a step of forming a carbon nanotube layer according to an embodiment of the present invention, FIG. 6 is a flowchart for explaining a method for manufacturing a heating paste according to an embodiment of the present invention, FIG. 7 is a diagram for explaining a step of manufacturing a first solution according to an embodiment of the present invention, FIG. 8 is a diagram for explaining a step of manufacturing a second solution according to an embodiment of the present invention, FIG. 9 is a diagram for explaining a step of manufacturing a heating paste according to an embodiment of the present invention, and FIG. 10 is a diagram for explaining a step of forming a heating layer according to an embodiment of the present invention.

[0037] Referring to FIGS. 1 and FIGS. 2, a substrate (100) is prepared (S100).

[0038] The above substrate (100) can perform a load-bearing function. For example, the above substrate (100) may be any one of a metal thin film, a carbon fiber fabric, a silica fiber fabric, or a composite panel.

[0039] For example, if the substrate (100) is the silica fiber fabric, the mechanical advantages of the fabric material are taken into account, and at the same time, when a carbon source is provided on the substrate (100) in the step of forming the carbon nanotube layer described later, the carbon nanotube layer can be easily formed. Furthermore, since the silica fiber fabric does not react with the electrode active material, the loss of mechanical performance of the structured battery described later can be minimized.

[0040] As another example, if the substrate (100) is the carbon fiber fabric, the mechanical properties and thermal stability of the structured battery described later may be improved. As a result, the lifespan and cycle characteristics of the structured battery described later may be improved.

[0041] In addition, the substrate (100) can be prepared by cleaning and drying it in advance to remove contaminants, moisture, and residual organic matter from the surface of the substrate (100).

[0042] Referring to FIG. 1 and FIG. 3, a first metal layer (201) is manufactured by providing a first metal nanoparticle containing Fe on the substrate (100) (S200).

[0043] According to one embodiment, the first metal nanoparticles on the substrate (100) may be provided using an electron beam evaporator (E-beam evaporator). Accordingly, the first metal layer (201), in which a plurality of first metal nanoparticles are uniformly and regularly arranged, can be easily formed. For example, the first metal particles may be iron nanoparticles. For example, the thickness of the first metal layer (201) may be 1 nm to 2 nm.

[0044] In addition, the first metal layer (201) can perform a catalyst function for carbon nanotube growth in the step of forming the carbon nanotube layer described later.

[0045] Referring to FIG. 1 and FIG. 4, a second metal nanoparticle containing Al is provided on the first metal layer (201) to form a second metal layer (202) that is thicker than the first metal layer (201) (S300).

[0046] According to one embodiment, the second metal nanoparticles on the substrate (100) may be provided using an electron beam evaporator (E-beam evaporator). Accordingly, the second metal layer (202), in which a plurality of the second metal nanoparticles are uniformly and regularly arranged, can be easily formed. For example, the second metal particles may be aluminum nanoparticles. For example, the thickness of the second metal layer (202) may be 8 nm to 10 nm.

[0047] In addition, the second metal layer (202) can not only function to promote the length growth and vertical growth of carbon nanotubes in the step of forming the carbon nanotube layer described later, but also perform a buffer function to improve the growth yield of carbon nanotubes.

[0048] Referring to FIGS. 1 and FIGS. 5, a carbon source is provided on the second metal layer (202) to form a carbon nanotube layer (300) (S400).

[0049] According to one embodiment, the carbon nanotube layer (300) can be easily formed by depositing the carbon source on the metal layer (202) using plasma-enhanced chemical vapor deposition (PECVD). For example, the carbon source may be methane (CH4). For example, the process temperature of the PECVD device may be controlled to 650°C to 700°C. For example, the thickness of the carbon nanotube layer (300) may be controlled to 0.5 µm to 50 µm.

[0050] As described above, the first metal layer (201) performs a catalytic function for the growth of carbon nanotubes from the carbon source, and the second metal layer (202), which is thicker than the first metal layer (201), performs a buffer function to promote the length growth and vertical growth of the carbon nanotubes, so that a plurality of carbon nanotubes can be easily generated and grown on a metal layer comprising the first metal layer (201) and the second metal layer (202).

[0051] Accordingly, the carbon nanotube layer (300) comprising a plurality of carbon nanotubes grown in a vertically aligned manner is easily formed, and the adhesion and stability between the interface between the substrate (100) and the first metal layer (201), the interface between the first metal layer (201) and the second metal layer (202), and the interface between the second metal layer (202) and the carbon nanotube layer (300) can be improved.

[0052] Accordingly, due to the synergistic effect of the first metal layer (201), the second metal layer (202), and the carbon nanotube layer (300) on the substrate (100), the mechanical and electrical performance of the electrode for a multi-purpose multi-functional structured battery described later can be improved.

[0053] Referring to FIGS. 6 to 9, a heating paste (480) is prepared as a source material for forming a heating layer to be described later.

[0054] Referring to FIGS. 6 and 7, a carbon nanotube (411), graphite (412), a dispersant (420), and a first solvent (430) are mixed to prepare a first solution (440) (S510).

[0055] According to one embodiment, the first solvent (430) may be of the Caprylyl acetate series. For example, the first solvent (430) may be Cabotol acetate. Accordingly, the π-π interaction between the carbon nanotube (411) and the graphite (412) is maintained, so that the carbon nanotube (411) and the graphite (412) remain stably dispersed in the first solution (440) for a long period without aggregation. For example, the dispersant (420) may be of the commercially available BYK series.

[0056] In contrast, when methyl ethyl ketone (MEK) or acetone is used as the first solvent (430), the evaporation rate of the first solvent (430) is significantly increased, so that the carbon nanotubes (411) and the graphite (412) aggregate and the dispersant (420) adsorbs to the carbon nanotubes (411) are suppressed, so that the carbon nanotubes (411) and the graphite (412) can aggregate in the first solution (440).

[0057] And, if any one of N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), or N,N-dimethylformamide (DMF) is used as the first solvent (430), the viscosity of the first solution (440) may increase rapidly and become gelled. As a result, it may be impossible to mix with the second solution (470) described later.

[0058] In addition, if toluene or hexane is used as the first solvent (430), the dispersant (420) may not perform its dispersion function normally, and the graphite (412) may not be dispersed.

[0059] Accordingly, according to an embodiment of the present application, in the step of preparing the first solution (440), a solvent of the Caprylyl acetate series may be used as the first solvent (430). Accordingly, the π-π interaction between the carbon nanotube (411) and the graphite (412) is maintained, so that the carbon nanotube (411) and the graphite (412) do not aggregate and remain stably dispersed in the first solution (440) over the long term.

[0060] Referring to FIGS. 6 and FIGS. 8, the thermoplastic binder (450) and the second solvent (460) are mixed to produce the second solution (470) described above (S520).

[0061] The thermoplastic binder (450) may be any one of thermoplastic polyurethane (TPU), polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride (PVDF), acrylic, or epoxy.

[0062] And, the second solvent (460) may include at least one of methyl ethyl ketone (MEK) or N,N-dimethylformamide (DMF).

[0063] According to one embodiment, the thermoplastic binder (450) may be a thermoplastic polyurethane (TPU). Compared to the thermoplastic binders described above, the thermoplastic polyurethane (TPU) has the best compatibility with the carbon nanotube (411) and the graphite (412), and improves leveling stability in the screen printing process, thereby providing the best stability of the printed heating layer (400) described later, as well as improved stability against mechanical stress applied during the operation of the structured battery described later.

[0064] In addition, the second solvent (460) may be a mixed solvent comprising the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF). Accordingly, the solubility of the thermoplastic polyurethane (TPU), which is the thermoplastic binder (450), is improved, and the drying speed of the heat-generating paste (480) described later can be optimized. Accordingly, the rheology for the screen printing process of the heat-generating paste (480) described later can be optimized.

[0065] In contrast, when the methyl ethyl ketone (MEK) is used alone as the second solvent (460), the drying speed of the heat-generating paste (480) described later can be significantly increased. Accordingly, the heat-generating layer (400) described later can be formed with an uneven thickness and shape.

[0066] In addition, if the N,N-dimethylformamide (DMF) is used alone as the second solvent (460), the viscosity of the heating paste (480) described later increases significantly, and a problem may occur in which residual solvent remains in the heating layer (400) described later.

[0067] Accordingly, according to an embodiment of the present application, the thermoplastic binder (450) may be the thermoplastic polyurethane (TPU). Accordingly, the stability of the printed heating layer (400) described later is improved by enhancing leveling stability in the screen printing process described later, and the stability against mechanical stress applied during the operation of the structured battery with the electrode described later can be improved.

[0068] In addition, the mixed solvent in which the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF) are mixed may be used as the second solvent (460). Accordingly, the solubility of the thermoplastic polyurethane (TPU), which is the thermoplastic binder (450), is improved, and the drying speed of the heat-generating paste (480) described later can be optimized. Accordingly, the rheology for the screen printing process of the heat-generating paste (480) described later is optimized, and a heat-generating layer (400) described later with improved stability can be formed.

[0069] Referring to FIGS. 6 and 9, the first solution (440) and the second solution (470) are mixed to produce the heating paste (480) described above (S530).

[0070] After mixing the first solution (440) and the second solution (470), the heating paste (480) can be manufactured by performing a 3-roll milling process.

[0071] Accordingly, a uniform shear force is provided to the carbon nanotubes (411) and the graphite (412) within the heating paste (480), so that the viscosity, thixotropy, and leveling level of the heating paste (480) can be optimized for screen printing.

[0072] In summary, the step of manufacturing the heating paste (480) may include the step of manufacturing the first solution (440) by mixing the carbon nanotube (411), the graphite (412), the dispersant (420), and the first solvent (430); the step of manufacturing the second solution (470) by mixing the thermoplastic binder (450) and the second solvent (460); and the step of manufacturing the heating paste (480) by mixing the first solution (440) and the second solution (470).

[0073] In the step of preparing the first solution (440), a solvent of the Caprylyl acetate series may be used as the first solvent (430). Accordingly, the π-π interaction between the carbon nanotube (411) and the graphite (412) is maintained, so that the carbon nanotube (411) and the graphite (412) do not aggregate and remain stably dispersed in the first solution (440) over the long term.

[0074] In addition, in the step of preparing the second solution (470), the thermoplastic binder (450) may be the thermoplastic polyurethane (TPU). Accordingly, the leveling stability in the screen printing process described later is improved, thereby improving the stability of the printed heating layer (400) described later, and also improving the stability against mechanical stress applied during the operation of the structured battery with the electrode described later.

[0075] Additionally, as the second solvent (460), the mixed solvent comprising the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF) may be used. For example, the volume ratio of the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF) may be controlled to be greater than 1:1 and less than 4:1. As a specific example, the volume ratio of the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF) may be controlled to be 6 to 7:3 to 4. Accordingly, not only is the solubility of the thermoplastic polyurethane (TPU), which is the thermoplastic binder (450), improved, but the drying speed of the heat-generating paste (480) described later can also be optimized. Accordingly, the rheology for the screen printing process of the heating paste (480) described below is optimized, and a heating layer (400) described below with improved stability can be formed.

[0076] Referring to FIG. 1 and FIG. 10, the heating paste (480) containing the carbon nanotube (411) and the graphite (412) is coated on the carbon nanotube layer (300) to form the heating layer (400) described above.

[0077] According to one embodiment, the heating paste (480) may be screen-printed onto the carbon nanotube layer (300) to form the heating layer (400). Accordingly, an electrode for a multi-functional multi-purpose structural battery may be manufactured on the substrate (100), comprising the first metal layer (201), the second metal layer (202), the carbon nanotube layer (300), and the heating layer (400).

[0078] The heating layer (400) can actively generate electrical heat when the structured battery to which the electrode is applied is exposed to a low-temperature environment, thereby locally raising the temperature of the electrode and electrolyte interface of the structured battery, and overcome problems such as reduced ion conductivity, increased internal resistance, reduced output, and reduced charge / discharge efficiency.

[0079] In conclusion, the method for manufacturing the electrode for a multi-functional multi-purpose structured battery according to an embodiment of the present application may include the steps of: preparing the substrate (100); providing the first metal nanoparticle containing Fe on the substrate (100) to form the first metal layer (201); providing the second metal nanoparticle containing Al on the first metal layer (201) to form the second metal layer (202) which is thicker than the first metal layer (202); providing the carbon source on the second metal layer (202) to form the carbon nanotube layer (300); and coating the heating paste (480) containing the carbon nanotube (411) and the graphite (412) on the carbon nanotube layer (300) to form the heating layer (400).

[0080] In the step of forming the carbon nanotube layer (300), the first metal layer (201) performs a catalytic function for the growth of carbon nanotubes from the carbon source, and the second metal layer (202), which is thicker than the first metal layer (201), can perform a buffer function to promote the length growth and vertical growth of the carbon nanotubes. Accordingly, a plurality of carbon nanotubes can be easily generated and grown on the metal layer comprising the first metal layer (201) and the second metal layer (202). Accordingly, the carbon nanotube layer (300) comprising a plurality of carbon nanotubes grown in a vertically aligned manner is easily formed, and the adhesion and interfacial stability can be improved at the interface between the substrate (100) and the first metal layer (201), the interface between the first metal layer (201) and the second metal layer (202), and the interface between the second metal layer (202) and the carbon nanotube layer (300). As a result, due to the synergistic effect of the first metal layer (201), the second metal layer (202), and the carbon nanotube layer (300) on the substrate (100), the mechanical performance and electrical performance of the electrode for a multi-purpose multi-functional structured battery can be improved.

[0081] And, the step of manufacturing the heating paste (480) may include the step of manufacturing the first solution (440) by mixing the carbon nanotube (411), the graphite (412), the dispersant (420), and the first solvent (430); the step of manufacturing the second solution (470) by mixing the thermoplastic binder (450) and the second solvent (460); and the step of manufacturing the heating paste (480) by mixing the first solution (440) and the second solution (470).

[0082] In the step of preparing the first solution (440), a solvent of the Caprylyl acetate series may be used as the first solvent (430). Accordingly, the π-π interaction between the carbon nanotube (411) and the graphite (412) can be maintained. As a result, the carbon nanotube (411) and the graphite (412) can be maintained in a stable, long-term dispersed state within the first solution (440) without aggregation.

[0083] In addition, in the step of preparing the second solution (470), the thermoplastic binder (450) may be the thermoplastic polyurethane (TPU). Accordingly, leveling stability in the screen printing process is improved, thereby improving the stability of the heating layer (400), and stability against mechanical stress applied during the operation of the structured battery to which the electrode is applied can be improved. Furthermore, as the second solvent (460), the mixed solvent in which the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF) are mixed may be used. Accordingly, the solubility of the thermoplastic polyurethane (TPU), which is the thermoplastic binder (450), is improved, and the drying speed of the heating paste (480) can be optimized. Accordingly, the rheology for the screen printing process of the heating paste (480) is optimized, and a heating layer (400) with improved stability can be formed.

[0084] The electrode for a multi-purpose structured battery manufactured by the manufacturing method described above may comprise the substrate (100), the first metal layer (201) having the first metal nanoparticle containing Fe on the substrate (100), the second metal layer (202) having the second metal nanoparticle containing Al on the first metal layer (201) and being thicker than the first metal layer (201), the carbon nanotube layer (300) on the second metal layer (202), and the heating layer (400) having the carbon nanotube (411) and the graphite (412) on the carbon nanotube layer (300).

[0085] Accordingly, the substrate (100) can perform the function of supporting the load of the structural battery to which the electrode is applied. Furthermore, since the carbon nanotubes within the carbon nanotube layer (300) are vertically aligned by the substrate (100), the first metal layer (201), and the second metal layer (202), the mechanical stability and conductivity of the electrode can be improved. In addition, conductivity and heating performance can be improved by the carbon nanotube layer (300) and the heating layer (40).

[0086] Accordingly, the mechanical strength, conductivity, and heat generation performance of the structural battery to which the above electrode is applied can be simultaneously improved.

[0088] Electrode for a multi-purpose multi-functional structural battery according to the first variant of the present invention

[0089] Unlike the method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to an embodiment of the present invention, the method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to a first modified example differs in that, after forming a carbon nanotube layer on a metal layer (first metal layer + second metal layer) on a substrate and before coating a heating paste, the carbon nanotube layer is surface-treated and a primer layer is formed on the surface-treated carbon nanotube layer. (For reference, the process of forming a carbon nanotube layer on a metal layer (first metal layer + second metal layer) on a substrate is identical to the method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to an embodiment of the present invention, and the technical effects thereof are also identical, so a detailed description is omitted. Furthermore, the composition of the heating paste, the composition of the heating layer formed by the heating paste, and the technical effects are identical to the method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to an embodiment of the present invention, so a detailed description is omitted.)

[0090] Hereinafter, with reference to FIGS. 11 to 13, a method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to a first modified example of the present invention is described.

[0091] FIG. 11 is a drawing for explaining the step of surface treating a carbon nanotube layer according to a first modified example of the present invention, FIG. 12 is a drawing for explaining the step of forming a primer layer according to a first modified example of the present invention, and FIG. 13 is a drawing for explaining the step of forming a heating layer according to a first modified example of the present invention.

[0092] Referring to FIGS. 1 to 5, a structure is provided comprising a first metal layer (201) on a substrate (100), a second metal layer (202) on the first metal layer (201), and a carbon nanotube layer (300) on the second metal layer (202).

[0093] Referring to FIGS. 1 to 5 and FIG. 11, the carbon nanotube layer (300) of the structure is surface-treated.

[0094] The carbon nanotube layer (300) may have hydrophobic surface characteristics. Accordingly, when a heating paste is coated on the carbon nanotube layer (300) to form a heating layer described later, the adhesion between the carbon nanotube layer (300) and the heating layer described later is weak, which may cause interfacial delamination problems. For example, the heating paste may have the same technical configuration as the heating paste according to the embodiment of the present application described with reference to FIGS. 6 to 9. Accordingly, the carbon nanotube layer (300) may be surface-treated before coating the heating paste on the carbon nanotube layer (300).

[0095] According to one embodiment, the step of surface treating the carbon nanotube layer (300) may include the step of heat treating the carbon nanotube layer (300) and the step of plasma treating the heat-treated carbon nanotube layer (300).

[0096] In the step of heat-treating the carbon nanotube layer (300), carbon nanotubes arranged vertically within the carbon nanotube layer (300) can be thermally stabilized. For example, the heat treatment can be performed at 80°C to 120°C for 10 to 30 minutes.

[0097] Subsequently, in the step of plasma treating the heat-treated carbon nanotube layer (300), polar functional groups of -OH and -COOH may be provided on the surface of the heat-treated carbon nanotube layer (300). For example, the plasma treatment may be performed at 10W to 80W for 5 to 30 seconds. Accordingly, a surface-treated (heat treatment + plasma treatment) carbon nanotube layer (301) may be prepared. Accordingly, the polar functional groups of the surface-treated carbon nanotube layer (301) and chains of a thermoplastic polymer (e.g., TPU) in the primer solution described later may interact.

[0098] Referring to FIGS. 11 and 12, a primer solution is coated on the surface-treated carbon nanotube layer (301) to form a primer layer (401).

[0099] The primer solution may be a solution in which the thermoplastic polymer is dissolved in a mixed solvent in which methyl ethyl ketone (MEK) and N,N-dimethylformamide (DMF) are mixed. For example, the thermoplastic polymer may be the same as the thermoplastic polymer of the heat-generating paste. For example, the thermoplastic polymer may be TPU. For example, the weight ratio of the thermoplastic polymer in the primer solution may be controlled to 1 wt% or less. For example, the volume ratio of the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF) in the mixed solvent may be controlled to 7.5 to 8.5:1.5 to 2.5.

[0100] According to one embodiment, the primer solution can be screen printed and dried on the surface-treated carbon nanotube layer (301). Accordingly, the primer layer (401), which functions as an adhesive connecting layer between the surface-treated carbon nanotube layer (301) and the heating layer described later, can be easily formed.

[0101] Accordingly, the primer layer (401) can interact with the molecular chains of the thermoplastic binder (e.g., TPU) of the heating paste, thereby improving the wettability of the heating paste coated on the primer layer (401). As a result, the problem of interfacial delamination between the untreated carbon nanotube layer (300) and the heating layer described later can be resolved.

[0102] Referring to FIGS. 11 to 13, the heating paste is coated on the primer layer (401) to form the heating layer (400) described above on the primer layer (401).

[0103] According to one embodiment, the heating paste can be screen-printed onto the primer layer (401) and dried to form the heating layer (400). Accordingly, an electrode for a multi-purpose multi-functional structural battery can be manufactured on the substrate (100), comprising the first metal layer (201), the second metal layer (202), the surface-treated carbon nanotube layer (301), the primer layer (401), and the heating layer (400).

[0104] At this time, through the primer layer (401), the polar functional groups of the surface-treated carbon nanotube layer (301) and the polymer chains within the heating layer (400) are connected, thereby improving adhesion and interfacial stability between the interface between the surface-treated carbon nanotube layer (301) and the primer layer (401) and the interface between the primer layer (401) and the heating layer (400). As a result, not only is the problem of interfacial delamination between the un-surface-treated carbon nanotube layer (300) and the heating layer (400) resolved, but mechanical stress applied to the structured battery to which the electrode for a multi-purpose multi-functional structured battery is applied can also be relieved by the primer layer (401).

[0105] In conclusion, the method for manufacturing the electrode for a multi-purpose multi-functional structured battery according to the first variant of the present application, unlike the method for manufacturing the electrode for a multi-purpose multi-functional structured battery according to the embodiment of the present application, may further include the step of surface treating the carbon nanotube layer (300) after forming the carbon nanotube layer (300) on the metal layer (the first metal layer (201) + the second metal layer (202)) on the substrate (100) and before coating the heating paste, and the step of forming the primer layer (401) by coating the primer solution on the surface-treated carbon nanotube layer (301).

[0106] In the step of surface treating the carbon nanotube layer (300), the carbon nanotubes vertically aligned within the carbon nanotube layer (300) are thermally stabilized, and the surface-treated carbon nanotube layer (301) having polar functional groups (e.g., -OH, -COOH) provided on its surface may be provided.

[0107] In addition, in the step of forming the primer layer (401) on the surface-treated carbon nanotube layer (301), the thermoplastic polymer (e.g., TPU) chains within the surface-treated carbon nanotube layer (301) and the primer solution interact, thereby improving adhesion and interfacial stability between the surface-treated carbon nanotube layer (301) and the primer layer (401).

[0108] Subsequently, during the process of coating the heating paste onto the primer layer (401), the chains of the thermoplastic polymer (e.g., TPU) of the primer layer (401) and the heating paste interact, thereby improving the wettability of the heating paste on the primer layer (401). Accordingly, the adhesion and interfacial stability between the primer layer (401) and the heating layer (400) formed by the heating paste can be improved.

[0109] As a result, the polar functional groups of the surface-treated carbon nanotube layer (301) and the polymer chains within the heating layer (400) are connected to the primer layer (401), thereby not only solving the problem of interfacial delamination between the untreated carbon nanotube layer (300) and the heating layer (400), but also allowing the mechanical stress applied to the structured battery to which the electrode for the multi-purpose multi-functional structured battery is applied to be relieved by the primer layer (401).

[0111] Electrode for a multi-purpose multi-functional structural battery according to a second variant of the present invention

[0112] Unlike the method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to the embodiment and the first modified example of the present invention, the method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to the second modified example differs in that a first heating paste and a second heating paste are sequentially coated on a carbon nanotube layer to sequentially form a first heating layer and a second heating layer. (For reference, the process of forming a carbon nanotube layer on a metal layer (first metal layer + second metal layer) on a substrate is identical to the method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to the embodiment of the present invention, and the technical effects thereof are also identical, so a detailed description is omitted.)

[0113] FIG. 14 is a drawing for explaining a structure having a first metal layer, a second metal layer, and a carbon nanotube layer formed on a substrate according to a second modified example of the present invention, FIG. 15 is a drawing for explaining the step of forming a first heating layer according to a second modified example of the present invention, and FIG. 16 is a drawing for explaining the step of forming a second heating layer according to a second modified example of the present invention.

[0114] Referring to FIG. 14 and FIG. 1 to 5, a structure is provided comprising a first metal layer (201) on a substrate (100), a second metal layer (202) on the first metal layer (201), and a carbon nanotube layer (300) on the second metal layer (202).

[0115] Referring to FIGS. 14 and 15, a first heating paste is screen-printed and dried on the carbon nanotube layer (300) of the structure to form a first heating layer (402).

[0116] The first heating paste may comprise graphite, carbon nanotubes, a thermoplastic binder, and a mixed solvent. For example, the weight ratio of the graphite, the carbon nanotubes, and the thermoplastic binder may be controlled to 60-80:5-20:5-10 wt%. For example, the thermoplastic binder may be TPU. For example, the volume ratio of methyl ethyl ketone (MEK) and N,N-dimethylformamide (DMF) in the mixed solvent may be controlled to 7-8:2-3.

[0117] Accordingly, since the weight ratio of the graphite in the first heating paste is controlled to be higher than that of the carbon nanotube, the graphite not only improves the wettability of the first heating paste but also allows for mechanical interlocking between the fine irregular shape on the surface of the carbon nanotube layer (300) and the first heating layer (402). As a result, adhesion, interfacial stability, and conductivity between the carbon nanotube layer (300) and the first heating layer (402) can be improved. That is, the first heating layer (402) can function as an interfacial buffer layer that corrects the surface of the carbon nanotube layer (300) having hydrophobic properties. For example, the thickness of the first heating layer (402) may be 5 µm to 30 µm.

[0118] Referring to FIGS. 14 to 16, a second heating paste is screen-printed and dried on the first heating layer (402) to form a second heating layer (404).

[0119] The second heating paste may include the graphite, the carbon nanotube, the thermoplastic binder, and the mixed solvent. Additionally, the second heating paste may be controlled to have a higher weight ratio of the carbon nanotube than the first heating paste. For example, the weight ratio of the graphite, the carbon nanotube, and the thermoplastic binder may be controlled to 20-40:40-60:5-10 wt%. For example, the thermoplastic binder may be TPU. For example, the volume ratio of the methyl ethyl ketone (MEK) and the N,N-dimethylformamide (DMF) in the mixed solvent may be controlled to 6-7:3-4.

[0120] Accordingly, the chains of the thermoplastic binder within the first heating layer (402) and the second heating paste interact, thereby improving the wettability of the second heating paste on the first heating layer (402). As a result, an electrode for a multi-purpose multi-functional structural battery can be manufactured in which the second heating layer (404) is uniformly formed on the first heating layer (402). For example, the thickness of the second heating layer (404) may be 5 µm to 25 µm.

[0121] At this time, since the weight ratio of the carbon nanotubes in the second heating paste is controlled to be higher than the weight ratio of the graphite, the heating characteristics of the electrode for the multi-purpose multi-functional structured battery can be improved, as well as the conductivity, by the carbon nanotubes uniformly dispersed in the second heating layer (404).

[0122] In conclusion, unlike the method for manufacturing the electrode for a multi-purpose multi-functional structured battery according to the second variant of the present application, the method for manufacturing the electrode for a multi-purpose multi-functional structured battery according to the embodiment and the first variant of the present application may include the step of sequentially coating the first heating paste and the second heating paste on a structure comprising the first metal layer (201), the second metal layer (202), and the carbon nanotube layer (300) on the substrate (100) to sequentially form the first heating layer (402) and the second heating layer (404).

[0123] Since the weight ratio of the graphite in the first heating paste is controlled to be higher than that of the carbon nanotube, the graphite not only improves the wettability of the first heating paste but also allows for mechanical interlocking between the fine irregular shape on the surface of the carbon nanotube layer (300) and the first heating layer (402). As a result, adhesion, interfacial stability, and conductivity between the carbon nanotube layer (300) and the first heating layer (402) can be improved. That is, the first heating layer (402) can function as an interfacial buffer layer that corrects the surface of the carbon nanotube layer (300) having hydrophobic properties.

[0124] In addition, since the weight ratio of the carbon nanotubes in the second heating paste is controlled to be higher than the weight ratio of the graphite, the heating characteristics of the electrode for the multi-purpose multi-functional structured battery can be improved by the carbon nanotubes, and the conductivity can also be improved.

[0126] Although the present invention has been described in detail using preferred embodiments, the scope of the invention is not limited to specific embodiments and should be interpreted by the appended claims. Furthermore, those skilled in the art will understand that many modifications and variations are possible without departing from the scope of the invention. Explanation of the symbols

[0127] 100: Substrate 201: First metal layer 202: Second metal layer 300: Carbon nanotube layer 400: Heating layer 401: Primer layer 402: First heating layer 404: Second heating layer 411: Carbon nanotubes 412: Graphite 420: Dispersant 430: First solvent 440: First solution 450: Thermal binder 460: Second solvent 470: Second solution 480: Heating paste

Claims

Claim 1 A method for manufacturing an electrode for a multi-purpose multi-functional structural battery, comprising: a step of preparing a substrate; a step of providing first metal nanoparticles containing Fe on the substrate to form a first metal layer; a step of providing second metal nanoparticles containing Al on the first metal layer to form a second metal layer thicker than the first metal layer; a step of providing a carbon source on the second metal layer to form a carbon nanotube layer; a step of surface treating the carbon nanotube layer; a step of forming a primer layer on the surface-treated carbon nanotube layer; and a step of printing a heating paste containing carbon nanotubes and graphite on the primer layer to form a heating layer. Claim 2 A method for manufacturing an electrode for a multi-purpose multi-functional structural battery, wherein the step of surface treating the carbon nanotube layer comprises: a step of heat treating the carbon nanotube layer at 80°C to 120°C for 10 minutes to 30 minutes; and a step of plasma treating the heat-treated carbon nanotube layer at 10W to 80W for 5 seconds to 30 seconds. Claim 3 A method for manufacturing an electrode for a multi-purpose multi-functional structural battery according to claim 2, wherein polar functional groups of -OH and -COOH are provided on the surface of a plasma-treated carbon nanotube layer, and the primer layer mediates the interaction between the polar functional groups and polymer chains within the heating layer to suppress interfacial delamination between the carbon nanotube layer and the heating layer. Claim 4 A multi-purpose multi-functional structural battery electrode comprising: a substrate; a first metal layer having first metal nanoparticles containing Fe on the substrate; a second metal layer thicker than the first metal layer having second metal nanoparticles containing Al on the first metal layer; a surface-treated carbon nanotube layer on the second metal layer; a primer layer on the surface-treated carbon nanotube layer; and a heating layer on the primer layer, wherein a polar functional group is provided on the surface of the surface-treated carbon nanotube layer, and the primer layer suppresses interfacial delamination between the carbon nanotube layer and the heating layer by mediating the interaction between the polar functional group and polymer chains within the heating layer. Claim 5 An electrode for a multi-purpose multi-functional structural battery according to claim 4, wherein the heating layer comprises a first heating layer and a second heating layer on the first heating layer, and the first heating layer and the second heating layer each comprise carbon nanotubes and graphite, wherein the first heating layer has a graphite content higher than the carbon nanotube content, and the second heating layer has a carbon nanotube content higher than the first heating layer.

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