Secondary Battery

Abstract

The present invention provides a secondary battery having a high energy density. [Solution] In order to increase the energy density of a secondary battery, minimize the possibility of fire and explosion, and minimize the problem of dendrite formation, a secondary battery is provided that includes a negative electrode structure in which the negative electrode material is a woven sheet of multiple yarns formed of carbon nanotube (CNT) fibers, in a secondary battery that includes a positive electrode material and a negative electrode material.

Description

[Technical Field]

[0001] Exemplary embodiments relate to secondary batteries. [Background technology]

[0002] As the popularity of electric vehicles that use secondary batteries as a source of driving range increases and the need for more widespread use of electric vehicles increases, interest in secondary batteries implemented in electric vehicles is also growing.

[0003] The capacity of a secondary battery is directly related to the operating time of the target device, such as the driving range of an electric vehicle, and at the same time, the problem of increased volume and weight of the target device must also be taken into consideration, so there is a very high demand for secondary batteries with high energy density.

[0004] There is also a significant demand for secondary batteries that have high stability and minimize the possibility of fire and explosion.

[0005] 2. Description of the Related Art Research into solid-state batteries has been actively conducted as a method for realizing high-capacity and high-stability secondary batteries. Summary of the Invention [Problem to be solved by the invention]

[0006] In solid-state batteries, the electrolyte of a battery composed of a liquid electrolyte is replaced with a solid electrolyte. When a solid electrolyte is used instead of a liquid electrolyte, there is no risk of electrolyte leakage, and a separator to prevent contact between the positive and negative electrodes is not required, allowing for the battery to be made smaller.

[0007] However, repeated charging processes can cause charge imbalances and uneven interfacial contact at the interface between the electrode and electrolyte, resulting in the formation of dendrites (lithium metal crystals), which can lead to electrode short circuits and a rapid decline in performance in solid-state batteries. [Means for solving the problem]

[0008] One or more embodiments of the present disclosure solve a variety of technical problems, including those mentioned above in the related art.

[0009] In one aspect, a secondary battery having a high energy density is provided.

[0010] In yet another aspect, a secondary battery is provided that minimizes the possibility of fire and explosion.

[0011] In yet another aspect, a secondary battery is provided that minimizes the problem of dendrite formation that occurs in the process of implementing a solid-state battery.

[0012] According to one aspect, a secondary battery is provided that includes a positive electrode material and a negative electrode material, wherein the negative electrode material includes a sheet-like negative electrode structure woven with multiple threads formed from carbon nanotube (CNT) fibers.

[0013] According to another aspect, the negative electrode structure can be a negative electrode current collector of a lithium ion battery.

[0014] According to one aspect, there is provided an anodeless secondary battery including a cathode material, an electrolyte, and a multi-thread woven sheet-like anode structure formed of CNT fibers contained in the electrolyte.

[0015] According to yet another aspect, the electrolyte can be a solid.

[0016] Additional aspects of the exemplary embodiments will be set forth in part in the description that follows, or will be apparent through the description, or may be learned by practice of the present disclosure. [Effects of the Invention]

[0017] Through this specification, the energy density of the secondary battery can be increased.

[0018] In addition, the possibility of fire and explosion of the secondary battery can be minimized.

[0019] In addition, the problem of dendrite formation that occurs when implementing an all-solid-state battery can be minimized. [Brief explanation of the drawings]

[0020] These and / or other aspects, features, and advantages of the present invention will be more clearly understood and readily appreciated through the following description of exemplary embodiments and with reference to the accompanying drawings, in which:

[0021] [Figure 1] This is a conceptual diagram of a conventional lithium-ion battery.

[0022] [Figure 2] 1 is a conceptual illustration of a carbon nanotube-based sheet according to the present invention. [Figure 3] 1 is a conceptual illustration of a carbon nanotube-based sheet according to the present invention.

[0023] [Figure 4] FIG. 2 is a front view of a portion of a negative electrode structure according to one embodiment of the present invention.

[0024] [Figure 5] FIG. 10 is a perspective view of a portion of a negative electrode structure according to still another embodiment of the present invention.

[0025] [Figure 6] 1 is a conceptual diagram of one embodiment of a secondary battery to which a negative electrode structure is applied.

[0026] [Figure 7A] 1 is an image of a twisted yarn and a braided yarn according to an embodiment of the present specification. [Figure 7B] 1 is an image of a twisted yarn and a braided yarn according to an embodiment of the present specification.

[0027] [Figure 8A] 1 illustrates a process for forming a negative electrode structure according to one embodiment of the present specification. [Figure 8B] 1 illustrates a process for forming a negative electrode structure according to one embodiment of the present specification. [Figure 8C] 1 illustrates a process for forming a negative electrode structure according to one embodiment of the present specification. [Figure 8D] 1 illustrates a process for forming a negative electrode structure according to one embodiment of the present specification.

[0028] [Figure 9A] The graph shows the mechanical properties depending on the type of yarn that makes up the negative electrode structure. [Figure 9B] The graph shows the mechanical properties depending on the type of yarn that makes up the negative electrode structure. [Figure 9C] The graph shows the mechanical properties depending on the type of yarn that makes up the negative electrode structure. [Figure 9D] The graph shows the mechanical properties depending on the type of yarn that makes up the negative electrode structure.

[0029] [Figure 10] 10 is a graph showing electrical properties when the negative electrode structure is made of twisted yarn and when it is made of braided yarn.

[0030] [Figure 11] 1 is a graph showing linear density when a negative electrode structure is formed from twisted yarn and when it is formed from braided yarn.

[0031] [Figure 12] 1 is a conceptual diagram showing a secondary battery or an all-solid-state battery not including a negative electrode material according to the present invention before and after lithium deposition. FIG. [Figure 13] 1 is a conceptual diagram showing a secondary battery or an all-solid-state battery not including a negative electrode material according to the present invention before and after lithium deposition. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0032] The terms used in the embodiments are currently commonly used and general terms that have been selected as much as possible while taking into consideration the functions in the present disclosure, but these may change depending on the intentions or precedents of engineers in the field, the emergence of new technologies, etc. In addition, in certain cases, the applicant may arbitrarily select terms, and in such cases, the meanings thereof will be described in detail in the relevant description. Therefore, the terms used in the present disclosure must be defined based on the meanings of the terms and the overall content of the present disclosure, rather than simply by the names of the terms.

[0033] The suffixes "module" and "section" used in the following description for components are given or mixed together solely for the convenience of drafting the specification and do not have any distinct meanings or functions. Furthermore, when describing the embodiments included in the present disclosure, if it is determined that a detailed description of related known technology may obscure the gist of the embodiments included in the present disclosure, the detailed description will be omitted. Furthermore, the attached drawings are provided merely to facilitate understanding of the embodiments included in the present disclosure, and should not be construed as limiting the technical spirit of the present disclosure, but should be understood to include all modifications, equivalents, and alternatives within the spirit and technical scope of the present disclosure.

[0034] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0035] When a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. On the other hand, when a component is referred to as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0036] The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0037] It should be understood that the terms "comprise" or "have" used throughout the specification are intended to specify the presence of any features, numerals, steps, operations, components, parts, or combinations thereof set forth in the specification, but do not preclude the presence or possible addition of one or more other features, numerals, steps, operations, components, parts, or combinations thereof.

[0038] Throughout the specification, the expression "at least one of a, b, and c" can encompass "a alone," "b alone," "c alone," "a and b," "a and c," "b and c," or "all of a, b, and c."

[0039]

[0033] The present disclosure will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein.

[0040] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0041] A secondary battery is a device that converts electrical energy into chemical energy, stores it (i.e., charges it), and converts the stored chemical energy back into electrical energy and releases it (i.e., discharges it). Secondary batteries can be implemented in various ways and can be particularly classified based on their materials, such as lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries.

[0042] In particular, lithium ion batteries have a high energy density relative to their mass and volume, and are advantageous for high-speed, high-rate charging and discharging. Recently, they have been widely used in devices that require high voltage and capacity, as well as in devices that are portable.

[0043] FIG. 1 is a conceptual diagram of a conventional lithium-ion battery 10.

[0044] A lithium-ion battery 10 is broadly composed of a cathode material 1, an anode material 2, an electrolyte 3, and a separator 4. The cathode material 1 serves as a source of lithium ions and determines the capacity and average voltage of the battery 10. The anode material 2 stores and then releases lithium ions released from the cathode material 1, while passing current through an external circuit. The electrolyte 3 helps the ions move smoothly between the cathode material 1 and the anode material 2, and the separator 4 prevents contact between the cathode material 1 and the anode material 2.

[0045] More specifically, the active material, the conductive material, the binder, and the current collector can constitute a positive electrode material 1 or a negative electrode material 2 .

[0046] Active materials are substances that are involved in the electrode reaction of the actual battery. Conductive materials increase the conductivity of the active materials, and binders bind the conductive materials and active materials to the current collector (or substrate). The current collector acts as a path for the smooth flow of electrons.

[0047] A typical active material for the cathode material 1 is lithium. Because lithium has unstable reactivity, lithium oxide bonded with oxygen can be used as the active material. Aluminum can be used as the current collector for the cathode material 1.

[0048] Meanwhile, the active material of the anode material 2 can be graphite, and the current collector can be copper (Cu). Graphite is widely used because it satisfies the requirements for the active material of the anode material 2, such as structural stability and low electrochemical reactivity, can store a large amount of lithium ions, and is inexpensive. The active material of the anode material 2 reversibly absorbs and releases lithium ions released from the cathode material 1, and passes current through an external circuit.

[0049] 2 and 3 are conceptual illustrations of a carbon nanotube-based sheet 20 according to the present invention.

[0050] The current collector of the negative electrode described above can be a carbon nanotube (CNT)-based sheet 20 instead of copper.

[0051] When the carbon nanotube-based sheet 20 is used as a current collector for a lithium-ion battery, it has the advantage that, unlike the negative electrodes of conventional secondary batteries, a binder can be omitted and the excellent electrical properties of carbon nanotubes can be fully utilized. Specifically, the carbon nanotube-based sheet 20 has high electrical conductivity, low density, and excellent electrochemical stability. In particular, the low-density carbon nanotube current collector can contribute to weight reduction of the lithium-ion battery.

[0052] The carbon nanotube-based sheet 20 may be an anisotropic sheet 20a in which the carbon nanotube fibers 101 constituting the sheet have a directional orientation, as shown in Figure 2, or a non-woven sheet 20b in Figure 3. However, despite the advantages described above, such sheets have several drawbacks when used as current collectors. Specifically, in the case of an oriented sheet 20a as shown in Figure 2, mechanical properties may be reduced in the direction perpendicular to the aligned direction, while in the case of a non-directionally aligned sheet 20b as shown in Figure 3, mechanical properties may be insufficient overall or may vary in parts, resulting in non-uniformity.

[0053] Fig. 4 is a partial front view of an anode structure 100 according to one embodiment of the present invention, and Fig. 5 is a partial perspective view of an anode structure 100 according to still another embodiment of the present invention. Fig. 6 is a conceptual diagram of one form of a secondary battery 200 to which the anode structure 100 of the embodiment of Fig. 4 or Fig. 5 is applied.

[0054] In this embodiment, a negative electrode structure 100 is proposed to complement the carbon nanotube-based sheet. The negative electrode structure 100 refers to a structure that is included in a negative electrode material and can be used as a current collector or a deposition-type negative electrode, which will be described later.

[0055] The negative electrode structure 100 may be a sheet woven with a plurality of yarns 110 formed from carbon nanotube fibers, that is, a carbon nanotube-based woven material.

[0056] Carbon nanotube-based woven materials have enhanced electrical and mechanical properties and can even ensure uniformity of the properties.

[0057] The specific manufacturing method and structure of the carbon nanotube-based woven material will be described below.

[0058] The negative electrode structure 100 may be a sheet woven with a plurality of yarns 110 formed from carbon nanotube fibers. The negative electrode structure 100 woven with the plurality of yarns 110 may have a certain pattern.

[0059] The negative electrode structure 100 may be woven in various ways. For example, the negative electrode structure may be woven in various ways, such as plain weaving, twill weaving, or satin weaving. That is, the negative electrode structure 100 may be formed without being limited to a specific weaving method as long as a regular texture can be formed. The negative electrode structure 100 formed by weaving may be in the form of a thin, wide sheet, and its rigidity may vary slightly depending on the weaving method. The negative electrode structure 100 shown in FIG. 4 or FIG. 5 conceptually illustrates some of the negative electrode structures 100 that may be woven in various ways described above. Therefore, any woven material that is not inconsistent with the described features may be the negative electrode structure 100 of the present invention.

[0060] The weave may have a sheet-like structure due to the structure of the plurality of yarns 110 itself without the addition of additional substances or physical / chemical processing. However, if necessary, additional substances or physical / chemical processing may be added, in which case the sheet structure may become more rigid.

[0061] The sheet-shaped anode structure 100 made of carbon nanotube fibers has high electrical conductivity, low density, and excellent electrochemical stability. In particular, the anode structure 100 formed by weaving does not have a single directionality, so there is little possibility of a sudden decrease in mechanical properties in one direction. In addition, because it has appropriate directionality, uniformity of mechanical properties can be ensured.

[0062] Such a woven sheet-like anode structure 100 has uniform physical properties, which minimizes manufacturing deviations. That is, because the anode structures 100 are woven in the same manner and have the same pattern, the weight, volume, thickness, etc., of the manufactured anode structures 100 are consistent, which allows for uniform physical properties of the secondary battery 200.

[0063] Furthermore, the woven sheet-like negative electrode structure 100 may have improved durability due to the reinforced structure in which the multiple yarns 110 are fastened together.

[0064] The negative electrode structure 100 having the above-described properties may be included in the negative electrode material 220 of the secondary battery 200. The negative electrode structure 100 may function as a framework, for example, a scaffold, within the negative electrode material 220.

[0065] Within the anode material 220, the void space created by the anode structure 100 can be left empty, filled with an all-solid electrolyte, or filled with a liquid electrolyte.

[0066] Alternatively, the empty space formed by the negative electrode structure 100 may be filled with at least one of an active material, a polymer material such as a binder, and a conductive material (metal nanoparticles or carbon nanoparticles).

[0067] The secondary battery 200 of the present invention may include a positive electrode material 210, a negative electrode material 220, an electrolyte 230, and a separator 240, and the features of each component are the same as those of the lithium-ion battery 10 described in Fig. 1 to the extent that they are not inconsistent with each other. Alternatively, the secondary battery 200 of the present invention may not include the separator 240.

[0068] 7A and 7B are photographs of a twisted yarn and a braided yarn according to one embodiment of the present specification, and FIG. 8 shows a process for forming a negative electrode structure according to one embodiment of the present specification.

[0069] A yarn can be defined as a yarn made by doubling multiple carbon nanotube fiber single yarns. A yarn can be defined as a yarn made by doubling two fiber single yarns, or a yarn made by doubling two yarns.

[0070] The negative electrode structure may be made of a twisted yarn as shown in Fig. 7A or a braided yarn as shown in Fig. 7B. Specifically, the negative electrode structure may be formed by weaving multiple twisted yarns or multiple braided yarns. Twisted yarns have the advantage of being easily manufactured, while braided yarns have the advantage of having excellent mechanical and electrical properties.

[0071] The properties of the twisted yarn and braided yarn will be described in detail with reference to FIGS.

[0072] The negative electrode structure can be formed by weaving multiple twisted yarns or multiple braided yarns. The term "unit yarn" as described below is defined as a yarn immediately before being woven into the negative electrode structure.

[0073] The unit yarn of the negative electrode structure woven via the process of Figures 8A and 8B is a twisted yarn.

[0074] 8A, the unit yarn constituting the negative electrode structure may be a primary twisted yarn, which is formed by twisting a plurality of carbon nanotube single yarns together.

[0075] 8B, the unit yarn constituting the negative electrode structure may be a secondary twisted yarn, which is formed by twisting a plurality of primary twisted yarns together.

[0076] In particular, the "twisting" to form the secondary twisted yarn is called "doubling."

[0077] 8C and 8D, the unit yarn constituting the negative electrode structure may be a braided yarn. The braided yarn may be formed by braiding multiple primary twisted yarns as illustrated in FIG. 8C, or may be formed by braiding multiple secondary twisted yarns as illustrated in FIG. 8D. The characteristics of the primary twisted yarn and secondary twisted yarn illustrated in FIG. 8C and 8D are the same as the characteristics of the primary twisted yarn and secondary twisted yarn illustrated in FIG. 8A and 8B.

[0078] However, the negative electrode structure is not limited to the above-described structure or the structure shown in Fig. 8, and the method for weaving the negative electrode structure is not limited as long as it is possible to form unit yarns that can be used to form a sheet-like negative electrode structure by weaving. For example, the negative electrode structure may be formed by various combinations of the methods shown in Figs. 8A to 8D, or by methods not described in Figs. 8A to 8D.

[0079] 9A to 9D show the mechanical properties depending on the type of yarn that makes up the negative electrode structure.

[0080] 9A to 9D show strain-stress curves for various types of yarns constituting the negative electrode structure. Each curve represents data obtained after multiple experiments. Figure 9A shows the results of deformation of a non-twisted yarn (64 fiber) made of 64 carbon nanotube single yarns. Figure 9B shows the results of deformation of a twisted yarn (75 twisted yarn, 64 fiber) made of 64 carbon nanotube single yarns twisted 75 times. Figure 9C shows the results of deformation of a twisted yarn (150 twisted yarn, 64 fiber) made of 64 carbon nanotube single yarns twisted 150 times. Figure 9D shows the results of deformation of a braided yarn (64 fiber) made of 64 carbon nanotube single yarns braided together.

[0081] 9A to 9C, it can be seen that when deformation is applied to a non-twisted yarn made of carbon nanotube fibers and a twisted yarn made of twisted carbon nanotube fibers, different stress characteristics are observed for each trial. On the other hand, when deformation is applied to a braided yarn made of braided carbon nanotube fibers, it can be seen that there is almost no difference in stress characteristics for each trial.

[0082] The mechanical properties of the unit yarns constituting the negative electrode structure described above are expressed in numerical values ​​as shown in Table 1 below.

[0083] [Table 1]

[0084] Referring to Table 1, it can be seen that when the unit yarns constituting the negative electrode structure are formed from braided yarn, the deviation values ​​of strain and stress are significantly lower than in other cases. Also, when considering the modulus of elasticity, which is the rate of change in stress with a change in strain, it can be seen that when the yarns constituting the negative electrode structure are formed from braided yarn, the deviation value is the smallest compared to other cases.

[0085] Referring to FIG. 9 and Table 1, when the unit yarns constituting the negative electrode structure are formed as braided yarns, the uniformity of mechanical properties can be improved compared to non-twisted yarns made by simply bundling carbon nanotube single yarns or twisted yarns.

[0086] FIG. 10 is a graph showing the electrical properties when the negative electrode structure is made of twisted yarn and when it is made of braided yarn.

[0087] Specifically, FIG. 10 shows the electrical conductivity depending on the type of unit yarn that constitutes the negative electrode structure.

[0088] Table 2 below shows the electrical properties of the negative electrode structure formed from twisted yarn and the negative electrode structure formed from braided yarn.

[0089] [Table 2]

[0090] 10 and Table 2, it can be seen that when the negative electrode structure is formed using braided yarn, the electrical conductivity is higher and the deviation is smaller than when the negative electrode structure is formed using twisted yarn. That is, when the negative electrode structure is formed using braided yarn, the uniformity of the electrical conductivity can be further improved.

[0091] FIG. 11 is a graph showing the linear density when the negative electrode structure is made of twisted yarn and when it is made of braided yarn.

[0092] Table 3 below shows the linear density in numerical terms when the negative electrode structure is made of twisted yarn and when it is made of braided yarn.

[0093] [Table 3]

[0094] Referring to FIG. 11 and Table 3, it can be seen that when the negative electrode structure is formed using braided yarn, the deviation in linear density is smaller than when using twisted yarn. Since changes in linear density can change the amount of current flowing through the negative electrode structure and its resistance, it can be understood that the more uniform the linear density, the more uniform the electrical characteristics. In other words, when the negative electrode structure is formed using braided yarn, the excellent uniformity of linear density can lead to uniform electrical characteristics.

[0095] 12 and 13 are conceptual diagrams showing a secondary battery 300 or an all-solid-state battery 300 that does not include the negative electrode material according to the present invention before and after lithium deposition.

[0096] The above-described anode structure 100 can also be applied to an anode-free secondary battery 300 or an all-solid-state battery 300.

[0097] All-solid-state batteries have the advantages of eliminating the risk of electrolyte leakage by incorporating a solid electrolyte, eliminating the need for a separator to prevent contact between the positive and negative electrodes, and reducing the weight and volume of the battery. That is, all-solid-state batteries offer the advantages of easy implementation of large-capacity batteries and high stability. One way to implement an all-solid-state battery is to use lithium metal as the anode material. Lithium metal has low oxidation / reduction reactivity and low density compared to other anode materials, and has a high theoretical capacity, allowing for the realization of high energy density per volume or weight. However, despite these advantages, the use of lithium metal can lead to the formation of lithium crystals on the surface of the anode during charging, a phenomenon known as dendrite formation. When dendrite formation occurs, irreversible lithium metal is formed and its volume changes. As a result, all-solid-state batteries can suffer from low Coulombic efficiency (i.e., poor cycle performance), poor interfacial contact, and potentially pose problems such as deformation, heat generation, short circuits, and fire.

[0098] To solve these drawbacks, the present invention proposes a secondary battery in which an anode structure 100 is applied to an anode-free secondary battery 300. The anode structure 100 applied to the anode-free secondary battery 300 simultaneously serves as the current collector and a deposition-type anode.

[0099] When the anode structure 100 is applied to the all-solid-state battery 300, lithium generated by the reduction of lithium ions is deposited in the vacant space of the electrode, thereby minimizing the change in the volume of the secondary battery.

[0100] Furthermore, lithium is uniformly deposited at the contact surface with the electrolyte, preventing the formation of dendrites. In particular, when the anode structure 100 woven with multiple yarns is applied to the all-solid-state battery 300, it has more uniform electrical conductivity than a typical sheet-type anode structure 100 rather than a woven one, thereby maintaining higher charge uniformity. This means that lithium is deposited uniformly from region to region.

[0101] Furthermore, the change in the shape of the electrode can be minimized through the fixed structure of the anode structure 100. That is, in the conventional case, repeated charge and discharge of a battery causes the anode composite to harden, which causes the shape of the electrode to change. However, when the anode structure 100 of the present invention is applied, the change in the shape of the electrode can be minimized due to its fixed structure even when the charge and discharge are repeated.

[0102] Specifically, the anode structure 100 may be disposed within a solid electrolyte 330, more specifically, a sulfide-based solid electrolyte 330, and used as a current collector in an anode-free battery.

[0103] That is, the all-solid-state battery 300 of the present invention may include a structure in which a cathode material 310 and a solid electrolyte 330 are sequentially stacked as shown in FIG. 12, or may include a structure in which a cathode material 310, a solid electrolyte 330, and a current collector 350 are sequentially stacked as shown in FIG. 13.

[0104] The anode structure 100 may be disposed within a layer of solid electrolyte 330. In particular, the anode structure 100 may be disposed distal to the cathode material 310 or adjacent to a layer of current collector 350.

[0105] In the all-solid-state battery 300 having the configuration shown in FIG. 12, the solid electrolyte 330 including the anode structure 100 serves as a current collector, and in the all-solid-state battery 300 having the configuration shown in FIG. 13, not only the layer of the solid electrolyte 330 including the anode structure 100 but also the layer of the separate current collector 350 may serve as a current collector.

[0106] By repeating charge and discharge, the lithium ions are reduced and can form lithium structures 340 deposited on the negative electrode structure 100.

[0107] The all-solid-state battery 300 to which the anode structure 100 is applied can have a small volume change as described above, and can ensure non-migration and charge uniformity. [Mode of Invention]

[0108] Any of the embodiments described herein or other embodiments are not mutually exclusive or distinct, and any of the embodiments described herein or other embodiments may be used in combination with or in combination of their respective configurations or functions.

[0109] For example, it means that the configuration A described in a particular embodiment and / or drawing can be combined with the configuration B described in another embodiment and / or drawing. In other words, even if a combination between configurations is not directly described, it means that the combination is possible unless it is described that the combination is impossible.

[0110] The above detailed description should not be construed as limiting in any respect, but should be considered as illustrative. The scope of the present specification should be determined by reasonable interpretation of the appended claims, and all modifications within the scope of the present specification that come within the equivalent range are included in the scope of the present specification.

[0111] These and other modifications may be applied to the embodiments based on the above detailed description. In general, the terms used in the following claims should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments to which such claims are entitled, and their equivalents. Accordingly, the scope of the claims is not limited by the specification. [Industrial Applicability]

[0112] The features of the present disclosure described above can be applied in part or in whole to the field of secondary batteries.

Claims

1. In a secondary battery including a positive electrode material and a negative electrode material, The negative electrode material is a sheet woven with a plurality of yarns formed from carbon nanotube fibers.

2. In an anode-free secondary battery, A cathode material, Electrolytes, A secondary battery comprising a negative electrode structure including a weaving sheet of a plurality of yarns formed of carbon nanotube (CNT) fibers contained in the electrolyte.

3. The secondary battery according to claim 1 , wherein each of the plurality of yarns is a braided yarn.

4. The braided yarn is formed by braiding a plurality of primary twisted yarns together, The secondary battery of claim 3 , wherein the primary twisted yarn is formed by twisting a plurality of carbon nanotube fibers.

5. The braided yarn is formed by braiding secondary twisted yarns together, The secondary twisted yarn is formed by twisting a plurality of primary twisted yarns together, The secondary battery according to claim 3 , wherein the primary twisted yarn is formed by twisting a plurality of carbon nanotube single yarns.

6. The secondary battery according to claim 1 , wherein each of the plurality of yarns is a twisted yarn.

7. The secondary battery according to claim 6 , wherein the twisted yarn is a primary twisted yarn formed by twisting a plurality of carbon nanotube single yarns.

8. The twisted yarn is a secondary twisted yarn formed by twisting primary twisted yarns together, The secondary battery according to claim 6 , wherein the primary twisted yarn is formed by twisting a plurality of carbon nanotube single yarns.

9. The secondary battery according to claim 1 , wherein the negative electrode structure is a negative electrode current collector of a lithium ion battery.

10. The secondary battery according to claim 2 , wherein the electrolyte is a solid.

11. The secondary battery of claim 10 , wherein the electrolyte comprises a sulfide-based material.

12. The secondary battery according to claim 1 , which does not include a separator.

13. The secondary battery according to claim 2 , wherein each of the plurality of yarns is a braided yarn.

14. The knitting yarn is formed by a plurality of primary twisted yarns knitted together, The secondary battery of claim 13 , wherein each of the plurality of primary twisted yarns is formed by a plurality of twisted CNT yarns.

15. The knitting yarn is formed by secondary twisted yarns knitted together, Each of the secondary twisted yarns is formed by a plurality of primary twisted yarns twisted together, The secondary battery of claim 13 , wherein each of the plurality of primary twisted yarns is formed by a plurality of twisted CNT yarns.

16. The secondary battery according to claim 2 , wherein each of the plurality of yarns is a twisted yarn.

17. 17. The secondary battery of claim 16, wherein the twisted yarn is a primary twisted yarn formed by multiple twisted CNT yarns.

18. the twisted yarn is a secondary twist yarn formed by primary twist yarns twisted together; 17. The secondary battery of claim 16, wherein each of the primary twisted yarns is formed by multiple twisted CNT yarns.

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