Electrodeless tab cable cell with high flexibility and low resistance

Abstract

Due to the linear structure of cable-type cells, when a battery cell is fabricated with electrode tabs formed on both ends, the increased battery length increases the distance electrons travel from the electrodes to the electrode tabs, resulting in increased battery resistance and a decrease in the electron transfer rate. To solve this problem, the outermost casing of the cable-type cell is configured so that the external electrodes are exposed from the interior member that constitutes the outermost casing of the cable-type cell, thereby providing the function of electrode tabs without the need for electrode tabs on the external electrodes. This provides a shortest path for electrons to pass from the active material layer of the electrode to the electrode tab, thereby confirming high flexibility and low resistance.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0095050, filed July 21, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an electrodeless tab cable cell having high flexibility and low resistance. Specifically, due to the linear structure of a cable cell in which electrode tabs are formed on both ends, the electron migration distance from the electrode to the electrode tab increases as the battery length increases, resulting in an increase in battery resistance and a decrease in electron migration rate. To solve this problem, the present invention relates to an electrodeless tab cable cell having high flexibility and low resistance, which can perform the function of an electrode tab without the need for an electrode tab on the external electrode by configuring the cable cell so that the external electrode is exposed from an interior member that forms the outermost shell of the cable cell. [Background technology]

[0003] 2. Description of the Related Art As the safety and capacity of rechargeable lithium secondary batteries continue to improve and increase, the number of devices using the lithium secondary batteries as an energy source is increasing.

[0004] For example, the lithium secondary battery is widely used as an energy source for wireless mobile devices or wearable devices, which are small, multi-functional products, and is also used as a medium- to large-sized battery pack for use as an energy source or energy storage system (ESS) for electric vehicles and hybrid electric vehicles, which are presented as alternatives to existing gasoline and diesel vehicles that cause air pollution.

[0005] Lithium secondary batteries are classified into cylindrical and prismatic battery cells, in which an electrode assembly is housed in a cylindrical or prismatic metal case, and pouch-type battery cells, in which an electrode assembly is housed in a pouch-type case made of an aluminum laminate sheet, depending on the shape of the battery case. Among these, pouch-type battery cells have the advantages of relatively large capacity and flexible structure.

[0006] Various wearable computer technologies and applications using such secondary batteries as a power supply have been developed and announced. Furthermore, electronic devices such as mobile phones and notebook computers are designed to have predetermined curved surfaces for ergonomic reasons. Therefore, secondary batteries for operating such electronic devices must also be formed to have various shapes, such as predetermined curved surfaces, depending on the shape of the electronic device.

[0007] In order to match the capacity and voltage according to the specifications of such devices, a pack may be constructed by connecting multiple pouch batteries in parallel or in series. However, this increases the thickness and volume of the entire pouch battery, reducing the flexibility of the battery itself, and mechanical stress is applied directly to the battery components during mechanical deformation, resulting in damage to the pouch battery and performance degradation.

[0008] In response to this, the concept of the linear cell, a cell with a very large ratio of length to diameter, was proposed.

[0009] FIG. 1 is a cross-sectional view of a conventional cable-type cell.

[0010] Referring to FIG. 1, the cable-type cell may include an internal electrode support 100 and an internal electrode 200 including a first internal current collector 210 and a first internal active material layer 220 wound in sequence around the internal electrode support 100.

[0011] An outer separation layer 300 may be formed on the outer side of the internal electrode 200 .

[0012] An external electrode 400 including an external active material layer 420 and an external current collector 410 may be formed on the outside of the external separation layer 300 .

[0013] An interior member 600 including a first interior member layer 610, a second interior member layer 620, a third interior member layer 630, and a fourth interior member layer 640 may be formed on the outside of the external electrode 400.

[0014] The first interior member layer 610 may be an adhesive layer for bonding the external current collector 410 and the interior member 600 together.

[0015] The second interior member layer 620 may be provided with a metal layer for blocking moisture and / or oxygen.

[0016] An insulating layer for insulation may be formed on the third interior material layer 630 and / or the fourth interior material layer 640.

[0017] The present invention includes an interior member. The interior member is an insulator and is formed on the outer surface of the external current collector to protect the electrode from moisture in the air and external impact. The interior member can be made of a conventional polymer resin containing a moisture barrier layer. The moisture barrier layer can be made of aluminum, liquid crystal polymer, or other materials with excellent moisture barrier properties.

[0018] The polymer resin may include any one selected from the group consisting of PET (polyethylene terephthalate), PVC (polyvinyl chloride), HDPE (high density polyethylene), and epoxy resin, or a mixture of two or more thereof.

[0019] FIG. 2 is a perspective view of the bidirectional electrode tabs of a conventional cable-type cell.

[0020] Referring to FIG. 2, electrode tabs are formed on both end surfaces of a conventional cable-type cell, and the electrode tabs can be connected to external terminals.

[0021] The electrode tab protruding from the lower end of FIG. 2 may be an internal electrode tab 230 of the internal electrode.

[0022] The electrode tab protruding from the upper end of FIG. 2 may be an external electrode tab 430 of the external electrode.

[0023] An internal electrode tab 230 may extend from the internal current collector, and an external electrode tab 430 may extend from the external electrode current collector, thereby forming a unidirectional cable cell in which the internal electrode tab and the external electrode tab protrude from one end of the cable cell.

[0024] A bidirectional cable cell may be formed in which the internal electrode tab 230 and / or the external electrode tab 430 are formed on both ends of the cable cell.

[0025] The interior member may be configured to surround the entire inner electrode, the outer separating layer, and the outer electrode, which are wound in this order around the inner electrode support.

[0026] Therefore, the electrode tabs of the internal electrode 200 and the external electrode 400 have a strip shape and are welded to both ends of the cable-type cell separately from the current collectors of the internal electrode 200 and the external electrode 400 .

[0027] Due to the linear structure of such cable-type cells, electrode tabs can only be formed on both ends of the battery. As the length of the battery increases, the distance that electrons travel from the electrode to the electrode tab increases, which increases battery resistance and reduces rate characteristics related to electron mobility.

[0028] Furthermore, in the case of a unidirectional cable type cell, the internal electrode tab and the external electrode tab are formed adjacent to each other, which can cause a short circuit due to contact between the two electrode tabs.

[0029] Therefore, a cable-type cell uses a tabless structure in which an electrically conductive material that acts as a positive electrode tab is applied to the outermost packaging of the cable-type cell, aiming to provide the shortest path for electrons to pass from the active material layer of the electrode to the electrode tab. This minimizes the resistance of the cable-type cell regardless of the length of the linear battery, thereby maintaining a balance between the battery length and the deterioration of electron transport characteristics.

[0030] Korean Patent Publication No. 10-2259381 discloses a flexible secondary battery including an electrode support, a sheet-shaped internal electrode spirally wound around the electrode support, a sheet-shaped first solid electrolyte layer spirally wound around the internal electrode, a sheet-shaped bipolar electrode spirally wound around the first solid electrolyte layer, a sheet-shaped second solid electrolyte layer spirally wound around the bipolar electrode, and a sheet-shaped external electrode spirally wound around the second solid electrolyte layer, wherein the first and second solid electrolyte layers include organic solid electrolytes, and the internal and external electrodes have insulating coating portions at both longitudinal ends of one side surface facing the first and second solid electrolyte layers, respectively, and the bipolar electrodes have insulating coating portions at both longitudinal ends of both sides.

[0031] However, the technology of the cable-type cell of the present invention, which uses the outermost shell of the cable-type cell as an electrode tab of the external electrode, has not been applied to a cable-type cell using a structure in which the interior member exposes the external electrode.

[0032] Korean Patent Registration No. 10-2128094 discloses a cable-type secondary battery including a cable-type electrode assembly including an internal electrode, a separation layer formed to surround the outer surface of the internal electrode and prevent short-circuiting of the electrodes, and an external electrode formed to surround the separation layer, and sheet-like packaging wound in a spiral shape around the outer surface of the cable-type electrode assembly.

[0033] However, there has been no disclosure of the technology of the cable-type cell of the present invention, in which an interior member that exposes the external electrodes is formed.

[0034] Japanese Patent Application Publication No. 2016-066520 discloses an electricity storage device in which a storage sheet composed of a positive electrode portion, a separator, and a negative electrode portion is spirally wound around a wire structure, gaps are formed between the wound storage sheets, and exposed portions are formed on the positive and / or negative electrode sheets of the storage sheet, which are exposed to the outside of the storage sheet and used as terminals.

[0035] However, there has been no disclosure of the technology of the cable-type cell of the present invention, in which an interior member that exposes the external electrodes is formed.

[0036] Japanese Patent Publication No. 2021-026957 discloses a negative electrode having a fiber bundle of bundled carbon fibers and a metal wire inserted into the fiber bundle along the longitudinal direction of the fiber bundle, and a pin-type secondary battery using the same.

[0037] However, in order to use the outermost periphery of the cable-type cell of the present invention as an electrode tab for an external electrode, a technology for a cable-type cell using an interior member that is wound up at intervals has never been applied.

[0038] Therefore, due to the linear structure of cable-type cells, when a battery cell is fabricated using both ends with electrode tabs, the distance that electrons travel from the electrodes to the electrode tabs increases as the battery length increases. To solve the problem of electron transfer speed due to increased battery resistance, there is a need to develop an electrodeless cable-type cell with high flexibility and low resistance, which can be achieved by removing the non-conductive material from the interior member that forms the outermost shell of the cable-type cell and forming the outermost shell of the cable-type cell with a conductive layer, thereby enabling the interior member to function as the electrode tab without the need to form electrode tabs on the external electrodes. Summary of the Invention [Problem to be solved by the invention]

[0039] The present invention has been made to solve the above-mentioned problems. When manufacturing a cable-type cell with electrode tabs formed on both ends, the distance that electrons travel from the electrodes to the electrode tabs increases as the battery length increases due to the linear structure of the cable-type cell, resulting in increased battery resistance and a decrease in electron transfer rate. To solve this problem, the present invention provides an electrodeless cable-type cell with high flexibility and low resistance, in which the non-conductive material of the interior member that forms the outermost shell of the cable-type cell is removed and the outermost shell of the cable-type cell is formed with a conductive layer, thereby allowing the interior member to function as the electrode tab without the need for electrode tabs on the external electrodes.

[0040] In addition, the pouch-type interior member, which is the outermost packaging of the cable-type cell, is configured to partially expose the external electrodes, forming a cable-type tabless structure in which the exposed external electrodes serve as electrode tabs, thereby providing the shortest path for electrons to move from the active material layer of the electrode to the electrode tab.

[0041] Another object of the present invention is to provide a cable-type cell including a cable-type tabless structure that can extend the length of the battery without any restrictions, in order to solve the problem of the deterioration of electron mobility characteristics as the length of existing cable-type cells increases. [Means for solving the problem]

[0042] To achieve this object, the present invention provides a cable-type cell for an electrodeless tab having high flexibility and low resistance, which includes an internal electrode support, a cable-type electrode assembly having a structure in which one or more internal electrodes, an external separator layer, and an external electrode are spirally wound around the internal electrode support in that order, and a laminate-type internal member that spirally winds the cable-type electrode assembly, and the internal member can be wound so as to expose the external electrode.

[0043] The interior member can partially expose the external electrodes.

[0044] The interior member may expose the external electrodes in a regular or irregular pattern.

[0045] The exposed portion of the external electrode can function as an electrode tab.

[0046] The interior member may be configured in a strip structure extending in one direction and wound up so that the external electrodes are partially exposed.

[0047] The internal electrode may be a cable-type cell having a mono-cell configuration including a first internal electrode including a first internal current collector and a first internal active material layer formed on one surface of the first internal current collector, the first internal electrode, the external separator, and the external electrode.

[0048] The external electrode may include an external current collector and an external active material layer formed on the inner surface of the external current collector, and may be a cable-type cell having a mono-cell configuration including the first internal electrode, the external separator, and the external electrode.

[0049] The internal electrode may include an internal separation layer wound in a spiral shape around the first internal electrode and a second internal electrode wound in a spiral shape around the internal separation layer, and the cell may be a cable-type cell having a bi-cell shape including the first internal electrode, the internal separation layer, the second internal electrode, the external separation layer, and the external electrode.

[0050] The second internal electrode may include a second internal current collector, and a second-first internal active material layer and a second-second internal active material layer formed on both surfaces of the second internal current collector, respectively.

[0051] The first internal electrode and the external electrode may have the same polarity, and the second internal electrode may have a polarity different from that of the first internal electrode and the external electrode.

[0052] If the first internal electrode and the external electrode are positive, the second internal electrode may be negative, and if the first internal electrode and the external electrode are negative, the second internal electrode may be positive.

[0053] Each of the inner and outer separation layers may be an electrolyte layer or a separator.

[0054] The external electrode may have a polymer layer formed in a spiral shape at predetermined intervals on an outer surface of the external current collector.

[0055] The interior member may be spirally wound around the outer surface of the external current collector so as to overlap at least a portion of the interior member with the polymer layer.

[0056] The polymer layer may be an adhesive layer for adhering the other surface of the external current collector to the interior member.

[0057] The polymer layer may be formed of one or more materials selected from the group consisting of polypropylene, polycarbonate, polyethylene, styrene butadiene rubber, sodium carboxymethyl cellulose, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polytetrafluoroethylene, polystyrene, polyacrylonitrile, polyimide, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan.

[0058] The interior member may be formed in a shape surrounding both ends of the cable-type cell.

[0059] When the cable-type cell is a mono-cell, the first internal current collector may have an internal electrode tab protruding from the interior member, and when the cable-type cell is a bi-cell, the second internal current collector may have an internal electrode tab protruding from the interior member.

[0060] The cross section of the cable-type cell may have any one of a circular, elliptical, triangular, quadrangular, square, rectangular, polygonal, and amorphous shape.

[0061] A cable-type cell of an electrodeless tab having high flexibility and low resistance according to the present invention may include a cable-type electrode assembly having a structure of two or more internal electrodes, an external separator layer formed to surround outer surfaces of the two or more internal electrodes and wound in a spiral, and an external electrode; and a laminate-type internal member that winds the cable-type electrode assembly in a spiral, wherein the internal member is wound so as to expose the external electrode.

[0062] The internal electrodes may be arranged such that two or more internal electrodes are in contact with each other in parallel, or may be arranged such that two or more internal electrodes are twisted together.

[0063] Furthermore, the present invention can also be provided in the form of various combinations of means for solving the above problems. [Effects of the Invention]

[0064] As described above, the highly flexible and low-resistance electrodeless tab cable cell according to the present invention can realize low resistance characteristics by providing the shortest path for electrons to pass from the active material layer of the electrode to the electrode tab.

[0065] In addition, the resistance of the battery can be minimized regardless of the length of the cable-type cell, thereby minimizing the deterioration of electron transport characteristics even when the battery length increases.

[0066] In addition, since the length can be extended without any restriction on the performance of the cable-type cell in response to various length changes required according to the shape requirements of the electrical device, the battery can be manufactured to fit the shape of various electronic devices. [Brief explanation of the drawings]

[0067] [Figure 1] FIG. 1 is a cross-sectional view of a conventional cable-type cell. [Figure 2] FIG. 1 is a perspective view of a bidirectional electrode tab of a conventional cable-type cell. [Figure 3] 1 is a schematic diagram of a cable-type cell to which an interior member with an exposed external current collector is applied according to an embodiment of the present invention. [Figure 4] 1 is a perspective view of a cable-type cell to which an interior member having an exposed external current collector is applied according to an embodiment of the present invention; [Figure 5] 2 is a cross-sectional view taken along line AA of a cable-type monocell in which an interior member according to an embodiment of the present invention exposes an external current collector. FIG. [Figure 6] 1 is a perspective view showing a configuration of an internal electrode tab of a cable-type cell to which an interior member having an exposed external current collector is applied according to an embodiment of the present invention; [Figure 7] 1 is a cross-sectional view of a BB line of a cable-type bi-cell in which an interior member exposes an external current collector according to an embodiment of the present invention. [Figure 8]1 is a schematic diagram of a cable-type cell including a plurality of internal electrodes in which an internal member exposes an external current collector so that the exposed external electrodes serve as electrode tabs according to an embodiment of the present invention. [Figure 9] 10 is a graph showing the resistance between the external electrode and the external electrode tab depending on the length of a conventional cable-type cell, a cable-type cell in which the interior member is a metal layer, and a cable-type cell according to an embodiment of the present invention. [Figure 10] 1 is a graph showing changes in resistance (R / R0) depending on the number of bending times for a conventional cable-type cell, a cable-type cell in which the interior member is a metal layer, and a cable-type cell according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0068] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person skilled in the art to easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0069] Throughout the drawings, the same reference numerals are used for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean that other elements are excluded, but that other elements may also be included.

[0070] Descriptions that limit or further embody elements are applicable to all inventions unless otherwise limited, and are not limited to descriptions of particular inventions.

[0071] Furthermore, throughout the description of the present invention and the claims, the singular includes the plural unless otherwise stated.

[0072] Throughout the description and claims, "or" includes "and" unless otherwise stated. Thus, "comprising A or B" means the three cases of including A, including B, or including both A and B.

[0073] The invention will now be explained with reference to the drawings and in conjunction with detailed embodiments.

[0074] FIG. 3 is a schematic diagram of a cable-type cell to which an interior member exposing an external current collector according to one embodiment of the present invention is applied, FIG. 4 is a perspective view of a cable-type cell to which an interior member exposing an external current collector according to one embodiment of the present invention is applied, and FIG. 5 is a cross-sectional view taken along line AA of a cable-type monocell in which an interior member exposing an external current collector according to one embodiment of the present invention.

[0075] 3 to 5, the cable-type cell includes an internal electrode support 100, a cable-type electrode assembly 500 having a structure in which one or more internal electrodes 200, an external separation layer 300, and an external electrode 400 are spirally wound around the internal electrode support 100 in this order, and a strip-shaped interior member 600 that spirally winds the cable-type electrode assembly 500, and the interior member 600 may be formed to expose at least a portion of the external electrode.

[0076] Here, the spiral shape is expressed as a spiral or a helix in English, and refers to a shape that is twisted and turned within a certain range, and is similar to the shape of a general spring.

[0077] The internal electrode 200, the external separation layer 300 and the external electrode 400 may have a strip structure extending in one direction.

[0078] That is, the interior member 600 is configured to surround the outermost external electrode 400 of the cable-type electrode assembly 500 in a loose spiral shape, and therefore, the spiral strips of the interior member 600 widen to form gaps through which the external electrode 400 can be exposed.

[0079] The interior member 600 can be made by cutting a laminate sheet having a multi-layer structure into strips as a battery case for a conventional pouch-type battery cell, and therefore, a separate description of the material and structure of the interior member will be omitted.

[0080] The internal electrode may include a first internal current collector 210 , a first internal active material layer 220 formed on the first internal current collector, and an internal electrode tab 230 .

[0081] The internal electrode tabs 230 are formed to protrude outward from both ends in the longitudinal direction of the cable-type cell.

[0082] The internal electrode includes a first internal electrode including a first internal current collector 210, a first internal active material layer 220, and an internal electrode tab 230, and a mono-cell type cable cell including the first internal electrode, an external separator 300, and an external electrode 400 may be configured.

[0083] In the cable-type cell, a part of the external current collector 410 of the cylindrical external electrode 400 is exposed and serves as an external electrode tab 430 .

[0084] The outer separating layers 300 can each be an electrolyte layer or a separator.

[0085] The external electrode 400 may include an external current collector 410 and an external active material layer 420 formed on the external current collector 410 .

[0086] The outer active material layer 420 is formed on the inner surface of the outer current collector 410 , and the interior member 600 can be configured to contact the outer surface of the outer current collector 410 .

[0087] The interior member 600 can partially expose the external electrode 400 .

[0088] The interior member 600 can expose the external electrodes 400 in a regular or irregular pattern.

[0089] The exposed portion of the external electrode 400 can function as an electrode tab.

[0090] The exposed portion of the external electrode 400 may be the external current collector 410 of the external electrode 400. That is, the external current collector 410 located at the outermost portion of the external electrode 400 may be exposed to the outside through a gap formed between the interior members 600.

[0091] An outer active material layer 420 is formed on the inner surface of the outer current collector 410, and the outer active material layer 420 contacts the outer separator layer 300 wound inside the outer electrode 400. The outer surface of the outer current collector 410 is exposed to the outside by the interior member 600, so that the portion exposed from the outer current collector 410 can function as an outer electrode tab 430.

[0092] In FIG. 4, the external current collector 410 is also labeled with the reference numeral of a conventional external electrode tab 430 .

[0093] Referring to FIG. 5, the cable-type cell according to the present invention has an internal electrode support 100 located at the most center, a first internal electrode having a first internal active material layer 220 formed on a first internal current collector 210, spirally wound around the external electrode support 100, an external separator 300 spirally wound around the external electrode, an external electrode 400 having an external active material layer 420 formed on an external current collector 410, spirally wound around the external separator 300, and an internal member 600 spirally wound around the external electrode 400 in close contact with the external electrode 400 such that a portion of the external current collector 410 of the external electrode 400 is exposed.

[0094] When looking at a cross section of the interior member 600 cut in the longitudinal direction of the cable-type cell, it is possible to see a shape in which concave and convex portions are repeated.

[0095] When viewing the end surface of the cable-type cell, an interior member 600 may be formed to surround the outer current collector 410, the outer active material layer 420, the outer separator 300, and even the first inner active material layer 220.

[0096] The internal electrode tab 230 may be formed on the first internal current collector 210 by welding, and an internal electrode tab weld 231 may be formed to connect an end of the first internal current collector 210 and the internal electrode tab 230 .

[0097] An internal electrode tab weld sealant layer 232 may be formed to non-conductively seal the internal electrode tab weld.

[0098] The ends of the internal electrode support 100 can also be surrounded by an interior member 600 .

[0099] A sealant layer may be further formed on the edge of the internal electrode support 100 .

[0100] The internal electrode support 100 may have an open structure with a space formed therein.

[0101] The inner electrode support 100 can be one or more spirally wound wires, one or more spirally wound sheets, twisted wire, linear wire, hollow fibers, or a mesh support.

[0102] The hollow fibers may be formed from one or more materials selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, polyimide, polyethylene terephthalate, polyamideimide, polyesterimide, polyethersulfone, and polysulfone.

[0103] The internal electrode support 100 may include two or more wire-type internal electrode supports wound in a helical shape so as to cross each other.

[0104] In the space formed inside the internal electrode support 100, an internal electrode current collector core part, a lithium ion supply core part containing an electrolyte, or a filling core part may be formed.

[0105] The inner electrode current collector core may be made of carbon nanotubes, stainless steel, aluminum, nickel, titanium, sintered carbon, or copper; stainless steel surface-treated with carbon, nickel, titanium, or silver; aluminum-cadmium alloy; non-conductive polymer surface-treated with a conductive material; or conductive polymer.

[0106] The lithium ion supply core may include a gel-type polymer electrolyte and a support.

[0107] The electrolyte may be a non-aqueous electrolyte using ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl formate (MF), gamma butyrolactone (γ-BL), sulfolane, methyl acetate (MA), or methyl propionate (MP).

[0108] The electrolyte may include an electrolyte selected from solid electrolytes using PEO (polyethylene oxide), PPO (polypropylene oxide), PEI (polyethylene imine), PES (polyethylene sulfide), or PVAc (polyvinyl acetate).

[0109] The electrolyte may further include a lithium salt.

[0110] The lithium salts include LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lithium lower aliphatic carboxylate, and lithium tetraphenylborate, or a mixture of two or more thereof.

[0111] The gel-type polymer electrolyte may be polyethylene oxide (PEO), polyvinylidene fluoride (PVdF), polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP), polymethymetacrylate (PMMA), polyacrylonitrile (PAN), or polyvinyl acetate (PVAc).

[0112] The first internal electrode includes a first internal current collector 210 and a first internal active material layer 220 formed on one surface of the first internal current collector 210, and the external electrode includes 400, an external current collector 410, and an external active material layer 420 formed on one surface of the external current collector 410.

[0113] The battery may further include a polymer film layer formed on one or more of the other surfaces of the first internal current collector 210 and the external current collector 410. By adding the polymer film layer, the active material layer can be supported by compensating for the thickness of the thin first internal current collector 210 and the external current collector 410. Furthermore, since a flexible polymer film layer is added, compared to increasing the thickness of the first internal current collector 210 and the external current collector 410 themselves, the first internal current collector 210 and the external current collector 410 can easily deform during the spiral winding process.

[0114] The polymer film layer may be formed of one selected from the group consisting of polyolefin, polyester, polyimide, and polyamide, or a mixture of two or more of these.

[0115] A polymer layer 440 may be further formed on at least one surface of the first inner active material layer 220 and the outer active material layer 420 .

[0116] The polymer layer 440 may be a porous polymer layer having a pore size of 0.01 μm to 10 μm and a porosity of 5% to 95%.

[0117] The polymer layer 440 may include a polar linear polymer, an oxide-based linear polymer, or a mixture thereof.

[0118] FIG. 6 is a perspective view showing the configuration of an internal electrode tab of a cable-type cell to which an interior member in which an external current collector is exposed according to an embodiment of the present invention is applied.

[0119] Referring to FIG. 6, the inner member 600 has a strip structure extending in one direction, and the inner member 600 can be wound around the outer electrode 400 with a predetermined exposed width.

[0120] The exposed width refers to the spacing of the interior member strip wound in a spiral shape so that a portion of the external electrode is exposed.

[0121] The exposed width is not limited to this width as long as it exposes the external current collector.

[0122] The exposed width may be 50% to 200% of the width of the wound external electrode.

[0123] That is, the external current collector 410 is formed in an exposed form so that the external electrodes function as electrode tabs, and thus electrode terminals can be connected to the outer surface of the cable-type cell in the longitudinal direction and both ends of the cable-type cell.

[0124] The internal electrode 200, which forms the opposite polarity to the external electrode 400, can be connected to an electrode terminal by an internal electrode tab 230 extending from the first internal electrode current collector 210 via an internal electrode tab welding portion.

[0125] FIG. 7 is a cross-sectional view of a BB line of a cable-type bi-cell in which an inner member exposes an external current collector according to an embodiment of the present invention.

[0126] Referring to FIG. 7, the cable-type cell according to the present invention has an internal electrode support 100 located at the center, a first internal electrode having a first internal active material layer 220 formed on a first internal current collector 210, wound spirally around the outside of the internal electrode support 100, an internal separator 800 wound spirally around the outside of the first internal electrode, and a second-second internal active material layer 730 and a second-first internal active material layer 710 formed on both sides of a second internal current collector 720. The second internal electrode 700 having the outer active material layer 420 formed on the outer current collector 410 is spirally wound around the outer separation layer 300, the outer current collector 410 is spirally wound around the outer separation layer 300, and the inner current collector 410 is spirally wound around the outer current collector 410 so that a portion of the outer current collector 410 of the outer electrode 400 is exposed.

[0127] 7 may be a bi-cell type cable cell in which a first internal electrode, an internal separation layer 800, a second internal electrode 700, an external separation layer 300, and an external electrode 400 are sequentially spirally wound around an internal electrode support 100. The internal electrode 200 includes an internal separation layer 800 spirally wound around the first internal electrode, and a second internal electrode 700 spirally wound around the internal separation layer 800.

[0128] The first internal electrode is configured similarly to the internal electrode 200 shown in Fig. 5. The second internal electrode 700 may include a second internal current collector 720, and a second-first internal active material layer 710 and a second-second internal active material layer 730 formed on both sides of the second internal current collector 720, respectively.

[0129] The first internal electrode and the external electrode 400 may have the same polarity, and the second internal electrode 700 may have a polarity different from that of the first internal electrode and the external electrode 400 .

[0130] If the first internal electrode and the external electrode 400 are positive, the second internal electrode 700 may be negative, and if the first internal electrode and the external electrode 400 are negative, the second internal electrode 700 may be positive.

[0131] Each of the inner and outer separating layers 800 and 300 can be an electrolyte layer or a separator.

[0132] A spirally wound polymer layer 440 may be formed on the outer surface of the external current collector 410 of the exposed external electrode 400, with gaps formed at predetermined intervals.

[0133] The interior member 600 may be formed on the outer surface of the external current collector 410 so as to at least partially overlap with the polymer layer 440 .

[0134] The polymer layer 440 may be an adhesive layer for bonding the outer surface of the external current collector 410 and the interior member 600 together.

[0135] The polymer layer 440 may be formed of one or more materials selected from the group consisting of polypropylene, polycarbonate, polyethylene, styrene butadiene rubber, sodium carboxymethyl cellulose, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polytetrafluoroethylene, polystyrene, polyacrylonitrile, polyimide, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan.

[0136] The polymer material of the adhesive layer is not limited as long as it can bond the exterior member and the interior member together.

[0137] The adhesive layer can be replaced with a pressure sensitive adhesive.

[0138] The interior member 600 may have a shape that surrounds both ends of the cable-type cell.

[0139] When the cable-type cell is the mono-cell, the first internal current collector 210 may have the internal electrode tab 230 protruding out of the interior member 600. When the cable-type cell is the bi-cell, the first internal current collector 210 may have the internal electrode tab 230 protruding out of the interior member 600, and the second internal current collector 720 may have the internal electrode tab 230 protruding out of the interior member 600.

[0140] The cross section of the cable-type cell may have any one of a circular, elliptical, triangular, quadrangular, square, rectangular, polygonal, and amorphous shape.

[0141] FIG. 8 is a schematic diagram of a cable-type cell including a plurality of internal electrodes in which the internal member exposes the external current collectors so that the exposed external electrodes serve as electrode tabs according to one embodiment of the present invention.

[0142] Referring to FIG. 8 , the cable-type cell may be a cable-type cell including a cable-type electrode assembly having a structure of two or more internal electrodes 200, an external separation layer 300 formed to surround the outer surfaces of the two or more internal electrodes 200 and wound in a spiral, and an external electrode 400, and a laminate-type internal member 600 wound around the cable-type electrode assembly in a spiral, the internal member 600 being formed so as to expose the external electrode 400.

[0143] The internal electrodes 200 may be arranged such that two or more internal electrodes 200 are in contact with each other in parallel, or may be arranged such that two or more internal electrodes 200 are twisted together.

[0144] The twisted configuration is not limited to a specific twisted configuration, but may be a configuration in which multiple electrodes are arranged parallel to each other and then twisted together, or multiple electrodes are offset from each other and twisted like tying hair.

[0145] When there are multiple internal electrodes 200, the internal electrodes 200 are densely packed together, thereby reducing the diameter of the cable-type cell according to the present invention. Such a cable-type cell can be thinner than a conventional cable-type cell, and therefore can be introduced into smart fabric or wearable applications by connecting a long cable-type cell in series or connecting multiple cells horizontally to form a sheet-like structure.

[0146] As described above, since the internal electrodes are densely packed with each other, the inner diameter of the cable-type cell according to the present invention can be reduced.

[0147] Here, if the internal electrode has a hollow structure, electrolyte can be injected through a needle. However, if the internal electrodes are tightly packed without a hollow, as described above, it is not easy to inject electrolyte using a needle as in the previous method. Therefore, the present inventors have researched a solution to electrolyte injection when the internal electrodes are not hollow, especially when solid internal electrodes are tightly packed. To this end, the inventors have devised a method in which the electrode assembly is passed through an electrolyte bath to absorb the electrolyte into the battery, and after impregnating the electrode assembly in the electrolyte bath, a polymer coating is applied to encapsulate the electrode assembly to prevent the electrolyte from leaking out.

[0148] Here, the polymer electrolyte layer used for encapsulation absorbs an electrolytic solution like a polymer electrolyte and has ion conductivity.

[0149] The cable-type secondary battery manufactured by this method has non-hollow, densely packed internal electrodes, and can easily be filled with an electrolyte.

[0150] (Comparative Example 1) A sheet-like interior member having a multi-layer structure was attached to surround the entire outer surface of a mono-cell type cable cell (pristine cable cell), and the resistance between the external electrode and the external electrode tab was measured. In the experiment, the external electrode was configured as a positive electrode. In this Comparative Example 1, the electrode tab extending from one of the ends of the cable cell served as the external electrode tab.

[0151] (Comparative Example 2) A sheet-like interior member having a single metal layer structure was attached to the entire outer surface of a mono-cell cable cell, and the resistance between the external electrode and the external electrode tab was measured. In this experiment, the external electrode was configured as a positive electrode. In this Comparative Example 2, the function of the external electrode tab was performed by the interior member.

[0152] Example 1 A mono-cell cable cell (Tabless cable cell 2) was spirally wound so that the multilayered interior member of the present invention partially exposed the external electrode, and the resistance between the external electrode and the external electrode tab was measured. In this experiment, the external electrode was configured as a positive electrode. In this Example 1, the function of the external electrode tab was performed by the externally exposed external electrode.

[0153] FIG. 9 is a graph showing the resistance between the external electrode and the external electrode tab depending on the length of a conventional cable-type cell, a cable-type cell in which the interior member is a metal layer, and a cable-type cell according to an embodiment of the present invention.

[0154] In the graph of FIG. 9, the conventional cable type cell is represented by Pristine cable cell, the cable type cell having a metal interior member is represented by Tabless cable cell, and the cable type cell of the present invention is represented by Tabless cable cell2.

[0155] Referring to FIG. 9, in the case of a pristine cable cell including an inner member having a multilayer structure according to Comparative Example 1, it can be seen that as the length of the cable cell increases, the resistance between the positive electrode and the positive electrode tab increases sharply in a 300 mm long cable cell.

[0156] In the case of a cable-type cell (Tabless cable cell) including an interior member having a single metal layer structure of Comparative Example 2, it can be confirmed that the resistance between the positive electrode and the positive electrode tab is measured to be 12.5 mOhm or less even in the case of a cable-type cell with a length of 500 mm due to the increase in the length of the cable-type cell.

[0157] In the case of a cable-type cell (Tabless cable cell 2) in which the interior member having a multilayer structure of the present invention in Example 1 partially exposes the external electrodes, it can be confirmed that the resistance between the positive electrode and the positive electrode tab is measured to be 12.5 mOhm or less even in the case of a cable-type cell with a length of 500 mm due to the increase in the length of the cable-type cell.

[0158] (Comparative Example 3) Both ends of a mono-cell type pristine cable cell including an interior member having a conventional multilayer structure of Comparative Example 1 were fixed, and an external force was repeatedly applied to the center, and the change in resistance (R / R0) of the assembly with increasing bending times was measured.

[0159] Comparative Example 4 The cable-type cell (Tabless cable cell 1) of Comparative Example 2, which constitutes an interior member made of only a single metal layer, was fixed at both ends, and an external force was repeatedly applied to the center, and the change in resistance (R / R0) of the assembly was measured as the number of bending cycles increased.

[0160] Example 2 The cable-type cell (Tabless cable cell 2) in which the multilayered interior member of the present invention partially exposed the external electrodes was fixed at both ends, and the resistance change (R / R0) of the assembly was measured as the number of bending cycles increased while repeatedly applying external force to the center.

[0161] FIG. 10 is a graph showing the change in resistance (R / R0) depending on the number of bending times for a conventional cable-type cell, a cable-type cell having an interior member made of only a single metal layer, and a cable-type cell according to an embodiment of the present invention.

[0162] In the graph of FIG. 10, the conventional cable-type cell is represented by Pristine cable cell, the cable-type cell in which the interior member is composed of only a single metal layer is represented by Tabless cable cell 1, and the cable-type cell of the present invention is represented by Tabless cable cell 2.

[0163] Looking closely at Figure 10, it can be seen that in the case of the pristine cable cell including the conventional multi-layered interior member of Comparative Example 3, the resistance change increases linearly with the increase in the number of bending cycles.

[0164] In the case of the cable-type cell (Tabless cable cell 1) including an interior member with a single metal layer structure in Comparative Example 4, it was confirmed that the change in resistance with the increase in the number of bending cycles was small. After 1,000 bending cycles, the change in resistance was confirmed to be one-third of that in Comparative Example 3.

[0165] In the case of a cable-type cell (Tabless cable cell 2) in which the interior member having the multilayer structure of the present invention in Example 2 partially exposes the external electrodes, it can be confirmed that there is almost no change in resistance up to 1,000 bending cycles.

[0166] Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above content. [Explanation of symbols]

[0167] 100 Internal electrode support 200 Internal electrode 210 First inner current collector 220 First inner active material layer 230 Internal electrode tab 231 Internal electrode tab weld 232 Internal electrode tab weld sealant layer 300 outer separation layer 400 external electrode 410 External current collector 420 Outer active material layer 430 External electrode tab 440 Polymer layer 500 Cable-type electrode assembly 600 Interior materials 610 1st interior material layer 620 2nd interior material layer 630 3rd interior material layer 640 4th interior material layer 700 2nd internal electrode 710 2nd-1 internal active material layer 720 Second internal current collector 730 2nd-2nd internal active material layer 800 internal separation layer

Claims

1. a cable-type electrode assembly having an internal electrode support, and one or more internal electrodes, an external separator layer, and an external electrode wound spirally around the internal electrode support in this order; a laminate-type interior member that spirally winds the cable-type electrode assembly, The interior member is wound up while exposing the external electrodes.

2. The cable-type cell according to claim 1 , wherein the interior member partially exposes the external electrodes.

3. The cable-type cell according to claim 2 , wherein the interior member exposes the external electrodes in a regular or irregular pattern.

4. 10. The cable-type cell of claim 1, wherein the exposed portions of the external electrodes function as electrode tabs.

5. The cable-type cell according to claim 1 , wherein the interior member is configured in a strip structure extending in one direction and wound up so that the external electrodes are partially exposed.

6. The internal electrode includes a first internal electrode including a first internal current collector and a first internal active material layer formed on one surface of the first internal current collector, The cable-type cell according to claim 1 , having a mono-cell configuration including the first internal electrode, the external separator layer, and the external electrode.

7. the external electrode includes an external current collector and an external active material layer formed on an inner surface of the external current collector, The cable-type cell according to claim 6 , having a mono-cell configuration including the first internal electrode, the external separator layer, and the external electrode.

8. The internal electrode is an internal separation layer formed by being wound in a spiral shape around the outer side of the first internal electrode; a second internal electrode wound in a spiral shape around the outer side of the internal separation layer, The cable-type cell according to claim 6 , in a bi-cell configuration, including the first internal electrode, the internal separation layer, the second internal electrode, the external separation layer, and the external electrode.

9. 9. The cable-type cell of claim 8, wherein the second internal electrode includes a second internal current collector, and a second-1 internal active material layer and a second-2 internal active material layer formed on both surfaces of the second internal current collector, respectively.

10. The cable-type cell according to claim 8 , wherein the first internal electrode and the external electrode are of the same polarity, and the second internal electrode is of a polarity different from that of the first internal electrode and the external electrode.

11. If the first internal electrode and the external electrode are positive electrodes, the second internal electrode is negative electrodes; The cable-type cell according to claim 8 , wherein if the first internal electrode and the external electrode are negative electrodes, the second internal electrode is positive.

12. 9. The cable-type cell according to claim 8, wherein each of the inner and outer separation layers is an electrolyte layer or a separator.

13. The cable-type cell according to claim 7 , wherein the external electrode has a polymer layer formed in a spiral shape at predetermined intervals on the outer surface of the external current collector.

14. The cable-type cell according to claim 13 , wherein the interior member is spirally wound around the outer surface of the external current collector so as to overlap at least a portion of the interior member with the polymer layer.

15. The cable-type cell according to claim 13 , wherein the polymer layer is an adhesive layer for bonding the other surface of the external current collector to the interior member.

16. 14. The cable-type cell according to claim 13, wherein the polymer layer is formed of one or more selected from the group consisting of polypropylene, polycarbonate, polyethylene, styrene-butadiene rubber, sodium carboxymethylcellulose, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polytetrafluoroethylene, polystyrene, polyacrylonitrile, polyimide, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan.

17. The cable-type cell according to claim 1 , wherein the interior member surrounds both ends of the cable-type cell.

18. When the cable-type cell is a mono-cell, the first internal current collector has an internal electrode tab protruding outward from the interior member, The cable type cell according to claim 17 , wherein when the cable type cell is a bi-cell type, the second internal current collector has an internal electrode tab protruding out of the interior member.

19. The cable-type cell according to claim 1 , wherein the cross section of the cable-type cell has any one of a circular, elliptical, triangular, quadrangular, square, rectangular, polygonal, and amorphous shape.

20. a cable-type electrode assembly having a structure of two or more internal electrodes, an external separation layer formed to surround outer surfaces of the two or more internal electrodes and wound in a spiral shape in order; and a laminate-type interior member that spirally winds the cable-type electrode assembly, A cable-type cell, wherein the interior member is wound up so as to expose the external electrode.

21. The internal electrodes are arranged such that two or more internal electrodes are in contact with each other in parallel, or 21. The cable-type cell of claim 20, wherein two or more internal electrodes are arranged in a twisted configuration with respect to each other.

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