Electrode tab-free cable-type cell having high flexibility and low resistance

Abstract

When a battery cell is manufactured to have electrode tabs formed at both ends, due to the linear structure characteristics of a cable-type cell, the distance of travel of electrons from an electrode to an electrode tab increases as the length of the battery increases, resulting in a decrease in the speed of movement of electrons upon an increase in battery resistance. To overcome such problems, the present invention relates to an electrode tab-free cable-type cell having high flexibility and low resistance, in which the outermost part of the cable-type cell is configured so that an external electrode is exposed from an internal member constituting the outermost part of the cable-type cell, and thus the function of electrode tabs can be provided without the need to form electrode tabs of external electrodes. By providing the shortest path through which electrons can pass from an active material layer of an electrode to an electrode tab, the high flexibility and low resistance characteristics may be confirmed.

Description

Cable-type cell without electrode tabs with high flexibility and low resistance

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

[0002] The present invention relates to a cable-type cell without electrode tabs, which is highly flexible and has low resistance. Specifically, due to the linear structure of the cable-type cell in which electrode tabs are formed at both ends, as the length of the cell increases, the distance that electrons travel from the electrodes to the electrode tabs increases, which causes a problem of electron movement speed due to increased battery resistance. In order to solve this problem, the present invention relates to a cable-type cell without electrode tabs, which is highly flexible and has low resistance, and which can function as an electrode tab by configuring the cable-type cell so that the external electrodes are exposed from the internal members forming the outermost part of the cable-type cell, thereby eliminating the need for forming electrode tabs for the external electrodes.

[0003] As the safety of rechargeable lithium secondary batteries is rapidly improving and their capacity is increasing, the types of devices that use the lithium secondary batteries as an energy source are increasing.

[0004] For example, the lithium secondary battery is not only widely used as an energy source for small, multi-functional products such as wireless mobile devices or wearable devices worn on the body, but is also used as an energy source for electric vehicles and hybrid electric vehicles, which are presented as alternatives to existing gasoline and diesel vehicles that cause air pollution, or as a medium- to large-sized battery pack for use as an energy storage system (ESS).

[0005] The above lithium secondary batteries are classified into cylindrical and prismatic battery cells, in which the electrode assembly is built into a cylindrical or prismatic metal can, and pouch-type battery cells, in which the electrode assembly is built into a pouch-type case made of 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 the ability to be structurally modified.

[0006] Various wearable computer technologies and applications utilizing these secondary batteries as a power source are being developed and announced. Furthermore, electronic devices such as cell phones and laptops are being designed with curved surfaces for ergonomics. Accordingly, the secondary batteries that power these electronic devices also need to be formed with various shapes, such as curved surfaces, to accommodate the specific configurations of the devices.

[0007] To match the capacity and voltage specifications of these devices, multiple pouch cells can be connected in parallel or in series to form packs. However, this increases the thickness and volume of the entire pouch cell, reducing its flexibility. Furthermore, mechanical deformation can directly apply mechanical stress to the battery components, potentially damaging the pouch cell and degrading its performance.

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

[0009] Figure 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 (200) including an internal electrode support (100), a first internal current collector (210) formed by being sequentially wound around the internal electrode support (100), and a first internal active material layer (220).

[0011] An external separation layer (300) can be formed outside the inner electrode (200).

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

[0013] An internal member (600) including a first internal member layer (610), a second internal member layer (620), a third internal member layer (630), and a fourth internal member layer (640) can be formed outside the external electrode (400).

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

[0015] The second internal member layer (620) may be formed with a metal layer for moisture and / or oxygen blocking.

[0016] The third internal member layer (630) and / or the fourth internal member layer (640) may be formed as an insulating layer for insulation.

[0017] The present invention comprises an internal member, which is an insulator formed on the outer surface of the external current collector to protect the electrode from moisture in the air and external impact. The internal member may be a conventional polymer resin including a moisture barrier layer. In this case, aluminum or a liquid crystal polymer with excellent moisture barrier performance may be used as the moisture barrier layer.

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

[0019] Figure 2 is a perspective view of a bidirectional electrode tab 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 can be connected to an external terminal.

[0021] The electrode tab protruding at the lower part of Fig. 2 may be an internal electrode tab (230) of the internal electrode.

[0022] The electrode tab protruding at the upper part of Fig. 2 may be an external electrode tab (430) of the external electrode.

[0023] The inner electrode tab (230) may be formed to extend from the inner current collector. The outer electrode tab (430) may be formed to extend from the outer electrode current collector. Accordingly, a unidirectional cable-type cell may be formed in which the inner electrode tab and the outer electrode tab protrude from one end of the cable-type cell.

[0024] A bidirectional cable-type cell can be formed in which internal electrode tabs (230) and / or external electrode tabs (430) are formed at both ends of the cable-type cell.

[0025] The above-mentioned internal member can be added in a form that wraps around the internal electrode, the external separation layer, and the entire external electrode, which are sequentially wound around the internal electrode support.

[0026] Accordingly, the electrode tabs of the inner electrode (200) and the outer electrode (400) are formed in a strip shape by welding separately from the current collectors of the inner electrode (200) and the outer electrode (400) to protrude at both ends of the cable-type cell.

[0027] Due to the linear structure of these cable-type cells, the electrode tabs of the electrodes can only be formed at both ends of the battery. As the length of the battery increases, the distance that electrons travel from the electrodes to the electrode tabs increases, which causes a problem in that the rate characteristics related to electron mobility deteriorate due to an increase in battery resistance.

[0028] In addition, in the case of a unidirectional cable-type cell, since the inner electrode tab and the outer electrode tab are formed adjacently, there is a problem of short circuit due to contact between the two electrode tabs.

[0029] Therefore, by using a tabless structure in which an electrically conductive material that acts as a positive electrode tab is applied to the outermost packaging of a cable-type cell, the shortest path for electrons to flow from the active material layer of the electrode to the electrode tab is provided, and the resistance of the cable-type cell is minimized regardless of the length of the linear battery, thereby balancing the length of the battery and the degradation of electron transport characteristics.

[0030] Korean Patent Publication No. 2259381 discloses a flexible secondary battery comprising: an electrode support; a sheet-shaped inner electrode spirally wound around the outside of the electrode support; a sheet-shaped first solid electrolyte layer spirally wound around the outside of the inner electrode; a sheet-shaped bipolar electrode spirally wound around the outside of the first solid electrolyte layer; a sheet-shaped second solid electrolyte layer spirally wound around the outside of the bipolar electrode; and a sheet-shaped outer electrode spirally wound around the outside of the second solid electrolyte layer, wherein the first solid electrolyte layer and the second solid electrolyte layer include an organic solid electrolyte, and wherein the inner electrode and the outer electrode have insulating coating portions at both longitudinal ends of one side facing the first solid electrolyte layer and the second solid electrolyte layer, respectively, and the bipolar electrode has insulating coating portions at both longitudinal ends of both side surfaces.

[0031] However, there has never been a cable-type cell technology applied in which the inner member for applying the outermost part of the cable-type cell of the present invention as an electrode tab of an external electrode has a structure that exposes the external electrode.

[0032] Korean Patent Publication No. 2128094 discloses a cable-type secondary battery including a cable-type electrode assembly including an inner electrode, a separation layer formed to surround the outer surface of the inner electrode and prevent short-circuiting of the electrode, and an outer electrode formed to surround the separation layer; and a sheet-shaped packaging formed by being spirally wound to surround the outer surface of the cable-type electrode assembly.

[0033] However, there has been no disclosure regarding a cable-type cell technology in which an internal member exposing the external electrode of the present invention is formed.

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

[0035] However, there has been no disclosure regarding a cable-type cell technology in which an internal member exposing the external electrode of the present invention is formed.

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

[0037] However, a cable-type cell technology that applies an internal member that is partially wound with a gap in order to apply the outermost part of the cable-type cell of the present invention as an electrode tab of an external electrode has never been applied.

[0038] Therefore, when manufacturing a battery cell using both ends where electrode tabs are formed due to the linear structure characteristics of a cable-type cell, the distance that electrons move from the electrodes to the electrode tabs increases as the length of the battery increases. Therefore, in order to solve the problem of electron movement speed due to increased battery resistance, the development of a highly flexible and low-resistance electrode-tab-less cable-type cell is required, in which the non-conductive material of the internal member constituting the outermost part of the cable-type cell is removed and the outermost part of the cable-type cell is formed with a conductive layer, so that the internal member can function as an electrode tab without the need to form an electrode tab of an external electrode.

[0039] The present invention is intended to solve the above problems, and when manufacturing a cable-type cell in which electrode tabs are formed at both ends, the resistance of the cell increases and the electron movement speed decreases because the distance of movement of electrons from the electrodes to the electrode tabs increases as the length of the cell increases due to the linear structure characteristic of the cable-type cell. In order to solve this problem, the present invention provides a highly flexible and low-resistance electrode tab-free cable-type cell in which the internal member can function as an electrode tab without the need to form an electrode tab of an external electrode by removing a non-conductive material of an internal member constituting the outermost part of the cable-type cell and forming the outermost part of the cable-type cell with a conductive layer.

[0040] In addition, the purpose is to provide the shortest path for electrons to move from the active material layer of the electrode to the electrode tab by forming a cable-type tabless structure in which a pouch-type inner member, which is the outermost packaging of the cable-type cell, is added to partially expose the external electrode and the exposed external electrode serves as an electrode tab.

[0041] In addition, in order to solve the problem of deterioration of electron movement characteristics as the length of the existing cable-type cell increases, the present invention aims to provide a cable-type cell including a cable-type tabless structure that can increase the length of the battery without restriction.

[0042] To achieve these purposes, a cable-type cell without electrode tabs having high flexibility and low resistance according to the present invention comprises an inner electrode support, one or more inner electrodes sequentially spirally wound around the inner electrode support, an outer separation layer, and a cable-type electrode assembly having an outer electrode structure, and a laminate-type internal member spirally wound around the cable-type electrode assembly, wherein the internal member can be wound while exposing the outer electrode.

[0043] The above-mentioned internal member may partially expose the above-mentioned external electrode.

[0044] The above-mentioned internal member can expose the external electrode regularly or irregularly.

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

[0046] The above-mentioned internal member is configured as a strip structure extending in one direction and can be wound so that the external electrode is partially exposed.

[0047] The above inner electrode may include a first inner electrode including a first inner current collector and a first inner active material layer formed on one surface of the first inner current collector, and may be a cable-type cell in the form of a monocell including the first inner electrode, the outer separation layer, and the outer electrode.

[0048] The above external electrode may be a cable-type cell in the form of a monocell including an external current collector and an external active material layer formed on the inner surface of the external current collector, and including the first internal electrode, the external separation layer, and the external electrode.

[0049] The inner electrode may include an inner separation layer formed by spirally winding on the outside of the first inner electrode and a second inner electrode formed by spirally winding on the outside of the inner separation layer, and may be a cable-type cell in the form of a bi-cell including the first inner electrode, the inner separation layer, the second inner electrode, the outer separation layer, and the outer electrode.

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

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

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

[0053] The inner separation layer and the outer separation layer may each be an electrolyte layer or a separator.

[0054] In the above external electrode, a polymer layer formed in a spiral shape with a predetermined interval can be formed on the outer surface of the external current collector.

[0055] The above-mentioned internal member can be spirally wound on the outer surface of the external current collector so as to overlap at least a portion of the above-mentioned polymer layer.

[0056] The above polymer layer may be an adhesive layer for bonding the other surface of the external collector and the internal member.

[0057] The above polymer layer may be formed of one or two 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.

[0058] The above-mentioned internal member can be formed in a shape that wraps around both ends of the cable-type cell.

[0059] When the cable-type cell is in the form of a monocell, the first internal current collector may have an internal electrode tab formed to protrude outside the internal member, and when the cable-type cell is in the form of a bicell, the second internal current collector may have an internal electrode tab formed to protrude outside the internal member.

[0060] The cross-section of the above cable-shaped cell may be any one of circular, elliptical, triangular, rectangular, square, rectangular, polygonal, and amorphous shapes.

[0061] A cable-type cell without electrode tabs having high flexibility and low resistance according to the present invention comprises a cable-type electrode assembly having a structure of two or more inner electrodes, an outer separation layer formed to surround the outer surfaces of the two or more inner electrodes and spirally wound in sequence, and a laminate-type internal member spirally wound around the cable-type electrode assembly, wherein the internal member may be a cable-type cell wound while exposing the outer electrodes.

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

[0063] The present invention can also be provided in a form in which various means for solving the above problem are combined.

[0064] As described above, the cable-type cell without electrode tabs having high flexibility and low resistance according to the present invention can implement low resistance characteristics by providing the shortest path through which electrons can pass from the active material layer of the electrode to the electrode tabs.

[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 transfer characteristics even when the length of the battery increases.

[0066] In addition, since the length can be increased without any restrictions on the performance of the cable-type cell in response to various length change requests according to the morphological requirements of the electric device, customized battery production is possible to fit the shape of various electronic devices.

[0067] Figure 1 is a cross-sectional view of a conventional cable-type cell.

[0068] Figure 2 is a perspective view of a bidirectional electrode tab of a conventional cable-type cell.

[0069] Figure 3 is a schematic diagram of a cable-type cell in which an internal member is reflected while exposing an external collector according to one embodiment of the present invention.

[0070] FIG. 4 is a perspective view of a cable-type cell in which an internal member is reflected while exposing an external collector according to one embodiment of the present invention.

[0071] FIG. 5 is a cross-sectional view AA of a cable-type monocell in which an internal member exposes an external collector according to one embodiment of the present invention.

[0072] FIG. 6 is a perspective view showing the configuration of an internal electrode tab of a cable-type cell in which an internal member is reflected to expose an external collector according to one embodiment of the present invention.

[0073] Fig. 7 is a BB cross-sectional view of a cable-type bicell in which an internal member exposes an external collector according to one embodiment of the present invention.

[0074] 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 collector so that the exposed external electrodes serve as electrode tabs according to one embodiment of the present invention.

[0075] FIG. 9 is a graph showing the resistance between an external electrode and an external electrode tab according to the length of a conventional cable-type cell, a cable-type cell in which the internal member is a metal layer, and a cable-type cell according to an embodiment of the present invention.

[0076] Figure 10 is a graph showing the change in resistance (R / R0) according to the number of bendings of a conventional cable-type cell, a cable-type cell having a metal layer as an internal member, and a cable-type cell according to an embodiment of the present invention.

[0077] Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail, so that those with ordinary skill in the art can easily implement the present invention. However, when describing the operating principles of preferred embodiments of the present invention in detail, if a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, such detailed description will be omitted.

[0078] Additionally, the same drawing reference numerals are used for parts with similar functions and actions throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only direct connections but also indirect connections with other elements intervening. Furthermore, inclusion of a component does not exclude other components unless specifically stated otherwise, but rather implies the inclusion of additional components.

[0079] Additionally, the description that concretizes or adds components may be applied to all inventions unless there are special limitations, and is not limited to the description of a specific invention.

[0080] Additionally, throughout the description and claims of the invention herein, the singular includes the plural unless otherwise stated.

[0081] Additionally, throughout the description and claims of the present invention, the term "or" includes "and" unless otherwise stated. Therefore, "comprising A or B" means all three cases of including A, including B, or including A and B.

[0082] The present invention is described in detail with examples according to the drawings.

[0083] Fig. 3 is a schematic diagram of a cable-type cell with an internal member that exposes an external collector according to an embodiment of the present invention. Fig. 4 is a perspective view of a cable-type cell with an internal member that exposes an external collector according to an embodiment of the present invention. Fig. 5 is a cross-sectional view taken along the line AA of a cable-type monocell with an internal member that exposes an external collector according to an embodiment of the present invention.

[0084] Referring to FIGS. 3 to 5, a cable-type cell includes an inner electrode support (100), a cable-type electrode assembly (500) having a structure in which one or more inner electrodes (200), an outer separation layer (300), and an outer electrode (400) are spirally wound around the inner electrode support (100) in that order, and an internal member (600) in the form of a strip that spirally winds the cable-type electrode assembly (500), and the internal member (600) can be formed to expose at least a portion of the outer electrode.

[0085] Here, the above-mentioned spiral is expressed as spiral or helix in English, and is a general term for a shape similar to the shape of a general spring, with a shape that is twisted and turned over a certain range.

[0086] The inner electrode (200), the outer separation layer (300), and the outer electrode (400) may have a strip structure extending in one direction.

[0087] That is, since the internal member (600) is added to loosely wrap the external electrode (400) located at the outermost side of the cable-type electrode assembly (500) in a spiral shape, a gap may be created between the spiral strips of the internal member (600) and the external electrode (400) may be exposed through the gap.

[0088] The internal member (600) can be used by cutting a laminate sheet having a multiple layered structure into a strip shape as a battery case of a conventional pouch-type battery cell, so the material and structure of the internal member will be described separately.

[0089] The above 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).

[0090] The internal electrode tab (230) is formed to protrude outward from both ends in the longitudinal direction of the cable-type cell.

[0091] The above internal electrode includes a first internal electrode including a first internal electrode, a first internal current collector (210), a first internal active material layer (220), and an internal electrode tab (230), and can form a cable-type cell in the form of a monocell composed of the first internal electrode, an external separation layer (300), and an external electrode (400).

[0092] In the above cable-type cell, the external current collector (410) of the external electrode (400) configured in a cylindrical shape is partially exposed and functions as an external electrode tab (430).

[0093] Each outer separation layer (300) may be an electrolyte layer or a separator.

[0094] 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).

[0095] An external active material layer (420) may be formed on the inner surface of the external current collector (410), and an internal member (600) may be added to contact the outer surface of the external current collector (410).

[0096] The internal member (600) can partially expose the external electrode (400).

[0097] The internal member (600) can expose the external electrode (400) regularly or irregularly.

[0098] The exposed portion of the external electrode (400) can perform the function of an electrode tab.

[0099] 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 side of the external electrode (400) may be exposed to the outside through a gap formed between the internal members (600).

[0100] The external current collector (410) has an external active material layer (420) formed on the inner surface, and the external active material layer (420) is in contact with the external separation layer (300) wound on the inner side of the external electrode (400), and the outer surface of the external current collector (410) is exposed to the outside by the internal member (500), so that the exposed portion of the external current collector (410) can perform the function of an external electrode tab (430).

[0101] Accordingly, it is confirmed that the drawing number of the external electrode tab (430) of the conventional invention is attached to the external current collector (410) in FIG. 4.

[0102] Referring to FIG. 5, the cable-type cell according to the present invention has an internal electrode support (100) positioned at the very center; a first internal electrode having a first internal active material layer (220) formed on a first internal current collector (210) is spirally wound around the outside of the internal electrode support (100); an external separation layer (300) is spirally wound around the outside of the first internal electrode; an external electrode (400) having an external active material layer (420) formed on an external current collector (410) is spirally wound around the outside of the external separation layer (300); and an internal member (600) is spirally wound while being in close contact with the external electrode (400) so that a part of the external current collector (410) of the external electrode (400) is exposed.

[0103] When examining the longitudinal cross-section of the cable-type cell of the internal member (600), one can see that the shape of the repetitive grooves and grooves are in the form of protrusions.

[0104] Looking at the end surface of the above cable-type cell, the internal member (600) can be formed by wrapping around the external current collector (410), the external active material layer (420), the external separation layer (300), and the first internal active material layer (220).

[0105] The internal electrode tab (230) is formed by welding with the internal current collector (210), and an internal electrode tab welding portion (231) connecting the end of the internal current collector (210) and the internal electrode tab (230) can be formed.

[0106] An internal electrode tab weld sealant layer (232) can be formed to non-conductively seal the internal electrode tab weld.

[0107] The end of the internal electrode support (100) can also be wrapped by the built-in member (600).

[0108] An additional sealant layer may be formed at the end of the internal electrode support (100).

[0109] The internal electrode support (100) may be an open structure with a space formed inside.

[0110] The internal electrode support (100) may be one or more spirally wound wires, one or more spirally wound sheets, a twisted wire, a linear wire, a hollow fiber, or a mesh-shaped support.

[0111] The above hollow fiber may be formed of at least one selected from the group consisting of polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, polyimide, polyethylene terephthalate, polyamide imide, polyester imide, polyether sulfone, and polysulfone.

[0112] The internal electrode support (100) may include two or more wire-shaped internal electrode supports wound in a spiral manner so as to intersect each other.

[0113] An internal electrode current collector core part, a lithium ion supply core part including an electrolyte, or a filling core part can be formed in a space formed inside the internal electrode support (100).

[0114] The above internal electrode current collector core part can 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.

[0115] The above lithium ion supply core part may include a gel-type polymer electrolyte and a support.

[0116] The above 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).

[0117] The above electrolyte may include an electrolyte selected from among solid electrolytes using PEO (polyethyleneoxide), PPO (polypropylene oxide), PEI (polyethylene imine), PES (polyethylene sulphide), or PVAc (polyvinyl acetate).

[0118] The above electrolyte may further include a lithium salt.

[0119] The above lithium salts are LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lithium lower aliphatic carboxylic acid, and lithium tetraphenylborate, or a mixture of two or more thereof.

[0120] The above gel-type polymer electrolyte may use PEO (polyethyleneoxide), PVdF (polyvinylidene fluoride), PVdF-HFP (poly vinylidene fluoride-co-hexafluoropropylene), PMMA (polymethymetacrylate), PAN (polyacrylonitrile), or PVAc (polyvinyl acetate).

[0121] The first internal electrode may include 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 may include (400), an external current collector (410) and an external active material layer (420) formed on one surface of the external current collector (410).

[0122] A polymer film layer formed on at least one of the other surfaces of the first inner current collector (210) and the other surfaces of the outer current collector (410) may be further included. By adding the polymer film layer, the thickness of the thin first inner current collector (210) and the outer current collector (410) can be supplemented to support the active material layer. In addition, rather than increasing the thickness of the first inner current collector (210) and the outer current collector (410) themselves, since a flexible polymer film layer is added, the first inner current collector (210) and the outer current collector (410) can be easily deformed during the spiral winding process.

[0123] The above 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 thereof.

[0124] A polymer layer (440) may be further formed on the surface of at least one of the first internal active material layer (220) and the external active material layer (420).

[0125] The above polymer layer may be a porous polymer layer having a pore size of 0.01 μm to 10 μm and a porosity of 5 to 95%.

[0126] The above polymer layer may include a polar linear polymer, an oxide-based linear polymer, or a mixture thereof.

[0127] FIG. 6 is a perspective view showing the configuration of an internal electrode tab of a cable-type cell in which an internal member is reflected to expose an external collector according to one embodiment of the present invention.

[0128] Referring to FIG. 6, the built-in member (600) has a strip structure extending in one direction, and the built-in member (600) can be wound around the external electrode (400) with a predetermined exposure width.

[0129] The above exposure width refers to the spacing between the spirally wound internal member strips so that a portion of the external electrode is exposed.

[0130] The above exposure width is not limited if the entire external body is exposed.

[0131] The above exposure width may be 50% to 200% of the width of the external electrode being wound.

[0132] That is, by forming an external collector (410) in an exposed form so that the external electrode performs the electrode tab function, electrode terminal connection is possible at the longitudinal outer surface of the cable-type cell and at both ends of the cable-type cell.

[0133] The internal electrode (200) forming the opposite pole to the external electrode (400) can be connected to the electrode terminal by the internal electrode tab (230) extended from the internal electrode current collector (210) through the internal electrode tab welding portion.

[0134] Fig. 7 is a BB cross-sectional view of a cable-type bicell in which an internal member exposes an external collector according to one embodiment of the present invention.

[0135] Referring to FIG. 7, the cable-type cell according to the present invention has an internal electrode support (100) positioned at the very center, a first internal electrode having a first internal active material layer (220) formed on a first internal current collector (210) is spirally wound around the outside of the internal electrode support (100), an internal separation layer (800) is spirally wound around the outside of the first internal electrode, a second internal electrode (700) having a second-second internal active material layer (730) and a second-first internal active material layer (710) formed on each of both sides of a second internal current collector (720) is spirally wound around the outside of the internal separation layer (800), an external separation layer (300) is spirally wound around the outside of the second internal electrode (700), and an external active material layer (420) is formed on an external current collector (410). The external electrode (400) is spirally wound on the outside of the external separation layer (300), and the internal member (600) is spirally wound while being in close contact with the external electrode (400) so that a part of the external current collector (410) of the external electrode (400) is exposed.

[0136] The cable-type electrode assembly (500) illustrated in FIG. 7 may be a bi-cell type cable-type cell that is sequentially composed of a first inner electrode, an inner separation layer (800), a second inner electrode (700), an outer separation layer (300), and an outer electrode (400) in a spirally wound form centered on an inner electrode support (100). The inner electrode (200) includes an inner separation layer (800) spirally wound on the outside of the first inner electrode, and a second inner electrode (700) spirally wound on the outside of the inner separation layer (800).

[0137] The first internal electrode is configured in the same manner as the internal electrode (200) illustrated in Fig. 5. The second internal electrode (700) may include 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) and the second internal current collector (720), respectively.

[0138] The first internal electrode and the external electrode (400) may have the same pole, and the second internal electrode (700) may have a different pole from the first internal electrode and the external electrode (400).

[0139] If the first internal electrode and external electrode (400) are positive electrodes, the second internal electrode (700) may be negative electrodes, and if the first internal electrode and external electrode (400) are negative electrodes, the second internal electrode (700) may be positive electrodes.

[0140] The inner separation layer (800) and the outer separation layer (300) may each be an electrolyte layer or a separator.

[0141] On the outer surface of the external current collector (410) of the exposed external electrode (400), a polymer layer (440) wound in a spiral shape can be formed so that a gap is formed and spaced apart at a predetermined interval.

[0142] The built-in member (600) can be formed on the outer surface of the external current collector (410) so as to overlap at least partly with the polymer layer (440).

[0143] The polymer layer (440) may be an adhesive layer for bonding the outer surface of the external collector (410) and the internal member (600).

[0144] The polymer layer (440) may be formed of one or two 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.

[0145] The polymer material of the adhesive layer is not limited as long as it can combine the outer member and the inner member.

[0146] The above adhesive layer can be replaced with an adhesive.

[0147] The built-in member (600) may be in a form that wraps around both ends of the cable-type cell.

[0148] If the cable-type cell is the monocell, the first internal current collector (210) may be formed such that the internal electrode tab (230) protrudes outside the internal member (600), and if the cable-type cell is the bicell, the first internal current collector (210) may be formed such that the internal electrode tab (230) protrudes outside the internal member (600), and the second internal current collector (720) may be formed such that the internal electrode tab (230) protrudes outside the internal member (600).

[0149] The cross-section of the above cable-shaped cell may be any one of circular, oval, triangular, rectangular, square, rectangular, polygonal, and amorphous shapes.

[0150] 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 collector so that the exposed external electrodes serve as electrode tabs according to one embodiment of the present invention.

[0151] Referring to FIG. 8, a cable-type cell includes a cable-type electrode assembly having a structure of two or more inner electrodes (200), an outer separation layer (300) formed to surround the outer surfaces of the two or more inner electrodes (200) and spirally wound in sequence, and an outer electrode (400); and a laminate-type internal member (600) spirally wound around the cable-type electrode assembly, and the internal member (600) may be a cable-type cell formed to expose the outer electrode (400).

[0152] The internal electrodes (200) may be arranged such that two or more internal electrodes (200) are in contact with each other in parallel, or two or more internal electrodes (200) may be arranged in a twisted form.

[0153] The above-mentioned twisted form is not limited to a specific twisted form, but can be twisted by placing multiple electrode strands side by side so that they are parallel to each other, or by twisting multiple electrode strands one by one like braiding long hair.

[0154] When there are multiple internal electrodes (200), they 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 made thinner than conventional cable-type cells, and thus can be introduced into smart fabrics or wearable applications by connecting cable-type cells in series or forming a sheet-type structure by connecting multiple cells horizontally.

[0155] By having a form in which the internal electrodes are densely packed together as described above, the internal diameter of the cable-type cell according to the present invention can be made small.

[0156] However, if the internal electrode has a hollow structure, the electrolyte can be injected through a needle, but if the internal electrode has a densely packed structure without a hollow structure as described above, it is not easy to inject the electrolyte using a needle as in the above method. Therefore, the present invention studied a method for solving the electrolyte injection problem when the internal electrode is not hollow, especially when non-hollow internal electrodes are densely packed together. To this end, the inventors devised a method of encapsulating the electrode assembly by passing the electrode assembly through an electrolyte bath so that the electrolyte is absorbed into the inside of the battery, and then performing a polymer coating to prevent the electrolyte from escaping to the outside after impregnation in the electrolyte bath.

[0157] At this time, the polymer electrolyte layer used for encapsulation absorbs electrolyte like a polymer electrolyte and has ionic conductivity.

[0158] A cable-type secondary battery manufactured through this method can facilitate electrolyte injection in a cable-type secondary battery having a densely packed, non-hollow internal electrode.

[0159] (Comparative Example 1)

[0160] A sheet-shaped internal member composed of multiple layers was attached to cover the entire outer surface of a monocell-type cable-type 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 an anode. In this comparative example 1, the electrode tab extending from one of the two ends of the cable-type cell functions as the external electrode tab.

[0161] (Comparative Example 2)

[0162] A sheet-shaped internal member made of a single-layer metal structure was attached to cover the entire outer surface of a monocell-type cable-type cell (Tabless 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 an anode. In this comparative example 2, the external electrode tab performs the function of the internal member.

[0163] (Example 1)

[0164] The multilayered internal member of the present invention was spirally wound with a mono-cell-shaped cable-type cell (Table 2) so that the external electrode was partially exposed, and the resistance between the external electrode and the external electrode tab was measured. In the experiment, the external electrode was configured as an anode. In this Example 1, the external electrode tab functions as an external electrode exposed to the outside.

[0165] FIG. 9 is a graph showing the resistance between an external electrode and an external electrode tab according to the length of a conventional cable-type cell, a cable-type cell in which the internal member is a metal layer, and a cable-type cell according to an embodiment of the present invention.

[0166] In the graph of Fig. 9, the conventional cable-type cell is indicated as a Pristine cable cell, the cable-type cell whose internal member is a metal layer is indicated as a Tabless cable cell, and the cable-type cell of the present invention is indicated as a Tabless cable cell 2.

[0167] Referring to FIG. 9, in the case of a cable-type cell (Pristine cable cell) including an internal member formed of a multilayer structure of Comparative Example 1, it can be confirmed that as the length of the cable-type cell increases, the resistance between the positive electrode and the positive electrode tab increases rapidly at a cable-type cell length of 300 mm.

[0168] In the case of a cable-type cell (Tabless cable cell) including an internal member made of a metal single-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 when the length of the cable-type cell is 500 mm as the length of the cable-type cell increases.

[0169] In the case of the cable-type cell (Table 2) in which the internal member formed of the multilayer structure of the present invention of Example 1 partially exposes the external electrode, 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 when the length of the cable-type cell is 500 mm as the length of the cable-type cell increases.

[0170] (Comparative Example 3)

[0171] The two ends of a monocell-shaped cable-type cell (Pristine cable cell) including an internal member made of 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 according to an increase in the number of bendings was measured.

[0172] (Comparative Example 4)

[0173] The two ends of a cable-type cell (Table 1) comprising an internal member composed of only a single metal layer of Comparative Example 2 were fixed, and an external force was repeatedly applied to the center, and the change in resistance (R / R0) of the assembly according to an increase in the number of bendings was measured.

[0174] (Example 2)

[0175] The internal member of the present invention, which is composed of a multilayer structure, was fixed at both ends of a cable-type cell (Tabless cable cell 2) with external electrodes partially exposed, and an external force was repeatedly applied to the center, and the change in resistance (R / R0) of the assembly according to an increase in the number of bends was measured.

[0176] Figure 10 is a graph showing the change in resistance (R / R0) according to the number of bendings of a conventional cable-type cell, a cable-type cell having an internal member composed of only a single metal layer, and a cable-type cell according to an embodiment of the present invention.

[0177] In the graph of Fig. 10, the conventional cable-type cell is indicated as a pristine cable cell, the cable-type cell comprising an internal member made of only a single metal layer is indicated as Tabless cable cell 1, and the cable-type cell of the present invention is indicated as Tabless cable cell 2.

[0178] Looking at Figure 10, in the case of a cable-type cell (Pristine cable cell) including an internal member made of a conventional multilayer structure of Comparative Example 3, it can be confirmed that the resistance change increases linearly as the number of bending cycles increases.

[0179] In the case of a cable-type cell (Table 1) including an internal member formed of a metal single-layer structure of Comparative Example 4, it can be confirmed that there is a minimal change in resistance as the number of bending cycles increases. After 1,000 bending cycles, the resistance change was confirmed to be about 1 / 3 of that of Comparative Example 3.

[0180] In the case of the cable-type cell (Table 2) in which the internal member of the present invention of Example 2 has a multilayer structure and partially exposes the external electrode, it can be confirmed that there is almost no change in resistance up to 1,000 bending cycles.

[0181] Anyone with ordinary knowledge in the field to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

[0182] (Explanation of symbols)

[0183] 100: Internal electrode support

[0184] 200: Internal electrode

[0185] 210: First internal collector

[0186] 220: First internal activation material layer

[0187] 230: Internal electrode tab

[0188] 231: Internal electrode tab welding part

[0189] 232: Sealant layer for internal electrode tab weld

[0190] 300: Outer separation layer

[0191] 400: External electrode

[0192] 410: External collector

[0193] 420: External active material layer

[0194] 430: External electrode tab

[0195] 440: Polymer layer

[0196] 500: Cable-type electrode assembly

[0197] 600: Internal parts

[0198] 610: First interior member layer

[0199] 620: Second internal member layer

[0200] 630: Third internal member layer

[0201] 640: 4th internal member layer

[0202] 700: Second internal electrode

[0203] 710: 2-1 Internal activation material layer

[0204] 720: Second inner collector

[0205] 730: 2nd-2nd internal activation material layer

[0206] 800: Inner separation layer

Claims

1. A cable-type electrode assembly having an inner electrode support, one or more inner electrodes sequentially spirally wound around the inner electrode support, an outer separation layer, and an outer electrode structure; and It includes a laminated internal member that spirally winds the above cable-type electrode assembly, The above-mentioned internal member is a cable-type cell that is wound while exposing the above-mentioned external electrode.

2. In paragraph 1, The above-mentioned internal member is a cable-type cell that partially exposes the above-mentioned external electrode.

3. In paragraph 2, The above-mentioned internal member is a cable-type cell that exposes the external electrode regularly or irregularly.

4. In paragraph 1, The exposed portion of the above external electrode is a cable-type cell that performs the function of an electrode tab.

5. In paragraph 1, The above-mentioned internal member is a cable-type cell composed of a strip structure extending in one direction, and wound so that the external electrode is partially exposed.

6. In paragraph 1, The above 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, A cable-type cell in the form of a monocell comprising the first inner electrode, the outer separation layer, and the outer electrode.

7. In paragraph 6, The above external electrode includes an external current collector and an external active material layer formed on the inner surface of the external current collector, A cable-type cell in the form of a monocell comprising the first inner electrode, the outer separation layer, and the outer electrode.

8. In paragraph 6, The above inner electrode comprises an inner separation layer formed by spirally winding on the outer side of the first inner electrode and It includes a second internal electrode formed in a spiral shape on the outside of the internal separation layer, A cable-type cell in the form of a bi-cell comprising the first inner electrode, the inner separation layer, the second inner electrode, the outer separation layer, and the outer electrode.

9. In paragraph 8, The above second internal electrode is a cable-type cell including a second internal current collector and a second-first internal active material layer formed on both sides of the second internal current collector, and a second-second internal active material layer.

10. In paragraph 8, A cable-type cell in which the first internal electrode and the external electrode have the same polarity, and the second internal electrode has a different polarity from the first internal electrode and the external electrode.

11. In paragraph 8, If the first internal electrode and the external electrode are positive electrodes, the second internal electrode is negative electrode, A cable-type cell in which the first internal electrode and the external electrode are cathodes and the second internal electrode is an anode.

12. In paragraph 8, A cable-type cell in which the inner separation layer and the outer separation layer are each an electrolyte layer or a separator.

13. In paragraph 7, A cable-type cell in which a polymer layer is formed in a spiral shape at a predetermined interval on the outer surface of the external current collector in the external electrode.

14. In paragraph 13, A cable-type cell in which the above-mentioned internal member is spirally wound on the outer surface of the external current collector so as to overlap at least a portion of the above-mentioned polymer layer.

15. In paragraph 13, The above polymer layer is a cable-type cell that is an adhesive layer for bonding the other surface of the external collector and the internal member.

16. In paragraph 13, The above polymer layer is a cable-shaped cell formed by one or two 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. In paragraph 1, The above-mentioned internal member is a cable-type cell that wraps around both ends of the cable-type cell.

18. In paragraph 17, If the above cable-type cell is in the form of a monocell, the first internal current collector is formed such that the internal electrode tab protrudes outside the internal member, When the above cable-type cell is in the form of a bi-cell, the second internal current collector is a cable-type cell in which the internal electrode tab protrudes outside the internal member.

19. In paragraph 1, The cable-shaped cell has a cross-section in any one of a circular, oval, triangular, rectangular, square, rectangular, polygonal, and amorphous shape. 20.2 or more inner electrodes, an outer separation layer formed to surround the outer surfaces of the two or more inner electrodes and spirally wound in sequence, and a cable-type electrode assembly having an outer electrode structure, and It includes a laminated internal member that spirally winds the above cable-type electrode assembly, The above-mentioned internal member is a cable-type cell that is wound while exposing the above-mentioned external electrode.

21. In paragraph 20, The above internal electrodes are arranged such that two or more internal electrodes are in contact with each other in parallel, or A cable-type cell in which two or more internal electrodes are arranged in a twisted manner.

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