Cable-type battery and manufacturing method therefor

Abstract

The present invention relates to a cable-type battery and a manufacturing method therefor, the cable-type battery comprising: a metal support; a first positive electrode wound around the outer surface of the metal support; a negative electrode-separator composite wound around the outer surface of the first positive electrode; a second positive electrode wound around the outer surface of the negative electrode-separator composite; and a case surrounding the outer surface of the second positive electrode, wherein the negative electrode-separator composite is formed such that a first separator, a negative electrode, and a second separator are bonded.

Description

Cable-type battery and method of manufacturing the same

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0198554 filed on December 27, 2024, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0002] The present invention relates to a cable-type battery and a method for manufacturing the same. Specifically, it relates to a cable-type battery comprising a negative electrode-separator composite integrally bonded with a negative electrode interposed between separators, and a method for manufacturing the same.

[0003]

[0004] As the safety and capacity of rechargeable lithium secondary batteries are rapidly improving, the types of devices using the aforementioned lithium secondary batteries as an energy source are increasing.

[0005] For example, the above-mentioned lithium secondary battery is not only widely used as an energy source for wireless mobile devices or wearable devices that are small, multifunctional products, but is also used as a medium-to-large 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 conventional gasoline and diesel vehicles that cause air pollution.

[0006] The above-mentioned lithium secondary batteries are classified according to the shape of the battery case into cylindrical and prismatic battery cells, in which an electrode assembly is embedded in a cylindrical or prismatic metal can, and pouch-type battery cells, in which an electrode assembly is embedded in a pouch-type case made of an aluminum laminate sheet. Among these, pouch-type battery cells have the advantages of relatively high capacity and easy structural deformation.

[0007] Meanwhile, as the thickness and volume of a pouch-type battery cell increase, the flexibility of the cell itself decreases, and if external pressure or impact is applied, direct stress is placed on the cell's components, which can damage the pouch-type battery cell. Furthermore, this can lead to the degradation of the pouch-type battery cell's performance.

[0008] In response to this, the concept of a linear cable-type battery with a very long length relative to its cross-sectional diameter was proposed.

[0009] FIG. 1 is a perspective view of a conventional cable-type battery, and FIG. 2 is a cross-sectional view of the cable-type battery of FIG. 1 before and after deformation, cut along A-A' of FIG. 1.

[0010] Referring to FIGS. 1 and 2, a cable-type battery (1000) comprises a metal support (100), a first positive electrode (200) added while spirally wrapping the metal support (100), a first separator (300) added while spirally wrapping the first positive electrode (200), a negative electrode (400) added while spirally wrapping the first separator (300), a second separator (500) added while spirally wrapping the negative electrode (400), a second positive electrode (600) added while spirally wrapping the second separator (500), a case (700) wrapping the second positive electrode (600), and an insulating tube (800) added to the outer surface of the case (700).

[0011] When winding each of the first positive electrode (200), first separator (300), negative electrode (400), second separator (500), and second positive electrode (600) in a spiral shape in a cable-type battery, if the ends of each are not fixed, the spiral winding state will unravel loosely, so it is necessary to fix them.

[0012] In other words, when venting a cable-type battery or using it in actual practice, if the unsecured end moves, the cable-type battery may be damaged.

[0013] Figure 2 (a) is a vertical cross-sectional view of the cable-type battery before deformation, and Figure 2 (b) is a vertical cross-sectional view of the cable-type battery after deformation so that it is bent.

[0014] In a cable-type battery, the first separator (300) and the second separator (500) are separated, and the negative electrode (400) is located between the first positive electrode (200) and the second positive electrode (600). In FIG. 2 (a), the first positive electrode (200), the negative electrode (400), and the second positive electrode (600) are in a state where there is no physical contact, but when deformed as in FIG. 2 (b), the negative electrode (400) comes into contact with at least one of the first positive electrode (200) and the second positive electrode (600), causing a short circuit.

[0015] Therefore, a structure is required that can improve safety by preventing short circuits in cable-type batteries.

[0016] Patent Document 1 discloses a cable-type secondary battery comprising: an internal electrode; a separator layer formed by winding spirally around the outer surface of the internal electrode to prevent a short circuit of the electrode; and a sheet-type separator layer-external electrode composite formed by compressing so as to integrate the external electrode.

[0017] Patent Document 1 provides a separator layer-external electrode composite to minimize the gap between the separator layer and the external electrode, and the separator layer in close contact with the external electrode absorbs the electrolyte to induce a uniform supply of electrolyte to the external electrode active material layer.

[0018] Patent Document 1 fails to provide an alternative to the problem of being vulnerable to short circuits when the cable-type battery is bent, as the electrode and separator are independently wound and attached in a spiral shape in a cable-type battery. Therefore, it is necessary to devise a solution for this.

[0019]

[0020] (Prior Art Literature)

[0021] (Patent Document 1) Korean Published Patent Application No. 2015-0051209 (May 11, 2015)

[0022]

[0023] The present invention aims to solve the above-mentioned problems by interposing the negative electrode between the separators and bonding them to form the negative electrode and the separators as an integrated unit, thereby providing a cable-type battery and a method for manufacturing the same that can prevent the positive and negative electrodes from coming into contact even if the cable-type battery is bent or curved.

[0024]

[0025] A cable-type battery according to the present invention for achieving such an objective comprises a metal support, a first positive electrode wound on the outer surface of the metal support, a negative electrode-separator composite wound on the outer surface of the first positive electrode, a second positive electrode wound on the outer surface of the negative electrode-separator composite, and a case surrounding the outer surface of the second positive electrode, wherein the negative electrode-separator composite may be in a form in which a first separator, a negative electrode, and a second separator are bonded together.

[0026] In the cable-type battery according to the present invention, the width of the first separator and the width of the second separator may be formed in a shape that is wider than the width of the negative electrode.

[0027] In a cable-type battery according to the present invention, the first separator and the second separator each include a first extension portion and a second extension portion that extend beyond the outer periphery of the negative electrode, and the first extension portion and the second extension portion may be bonded to each other.

[0028] In the cable-type battery according to the present invention, the first extension part and the second extension part may be configured to extend 2 mm to 3 mm beyond the outer periphery of the negative electrode.

[0029] In the cable-type battery according to the present invention, the first extension part and the second extension part may be heat-fused and bonded to each other.

[0030] In the cable-type battery according to the present invention, an insulating tube may be further added to the outer surface of the case.

[0031] In a cable-type battery according to the present invention, the first positive and the second positive may be composed of a single-sided electrode comprising a positive current collector and a positive active material layer formed on one surface of the positive current collector.

[0032] In the cable-type battery according to the present invention, the negative electrode may be composed of a negative electrode current collector and a double-sided electrode in which a negative active material layer is formed on each side of the negative electrode current collector.

[0033] The present invention provides a method for manufacturing a cable-type battery, comprising a first step of winding a first positive electrode onto a metal support, a second step of winding a negative electrode-separator composite onto the first positive electrode, a third step of winding a second positive electrode onto the negative electrode-separator composite, and a fourth step of wrapping the outer surface of the second positive electrode with a case.

[0034] In the method for manufacturing a cable-type battery according to the present invention, the negative electrode-separator composite comprises a first separator, a negative electrode, and a second separator, and the first separator, the negative electrode, and the second separator may be bonded together to form an integrated form.

[0035] In the method for manufacturing a cable-type battery according to the present invention, the first separator and the second separator each include a first extension portion and a second extension portion that extend beyond the outer periphery of the negative electrode, and the first extension portion and the second extension portion are bonded to each other so that the negative electrode is accommodated between the first separator and the second separator.

[0036] In the method for manufacturing a cable-type battery according to the present invention, after the fourth step, a fifth step of adding an insulating tube to the outer surface of the case may be included.

[0037]

[0038] The present invention can also be provided in a form that combines various means for solving the above problem.

[0039]

[0040] In the present invention, since the negative electrode and the separator are provided as an integrated unit, the state in which the separator is attached to the surface of the negative electrode is maintained even if the position of the negative electrode moves inside the cable-type battery.

[0041] Therefore, even if the cable-type battery is bent or kinked, direct contact between the negative and positive electrodes can be prevented.

[0042]

[0043] FIG. 1 is a perspective view of a conventional cable-type battery.

[0044] Figure 2 is a cross-sectional view of the cable-type battery of Figure 1 before and after deformation, cut along A-A' of Figure 1.

[0045] FIG. 3 is a perspective view of a cable-type battery according to the present invention.

[0046] Figure 4 is a cross-sectional view taken along B-B' of Figure 3.

[0047] FIG. 5 is a perspective view and a cross-sectional view of a cathode-separator composite wound in a spiral shape.

[0048] Figure 6 is an exploded perspective view of a cathode-separator composite.

[0049] FIG. 7 is a cross-sectional view of a cable-type battery according to the present invention before and after deformation, respectively.

[0050]

[0051] Embodiments that enable a person skilled in the art to easily practice the present invention are described in detail below with reference to the attached drawings. In describing the operating principles of the embodiments of the present invention in detail, specific descriptions of related known functions or configurations are omitted if it is determined that such detailed descriptions may unnecessarily obscure the essence of the present invention.

[0052] The same reference numerals are used for parts having similar functions and operations throughout the drawings. Throughout the specification, when a part is described as being connected to another part, this includes not only cases where they are directly connected but also cases where they are indirectly connected with other elements in between. Furthermore, the inclusion of a certain component means that, unless specifically stated otherwise, it does not exclude other components but rather implies that additional components may be included.

[0053] Descriptions that specify components by limiting or adding them may be applied to all inventions unless specifically limited, and are not limited to descriptions of specific inventions.

[0054] Throughout the description of the invention and claims of this application, anything indicated in the singular includes cases where it is plural unless otherwise noted.

[0055] Throughout the description of the invention and the claims of the present invention, "or" includes "and" unless otherwise noted. Therefore, "comprising A or B" means all three of the above cases: including A, including B, or including both A and B.

[0056] The present invention is described in detail with reference to the drawings and embodiments.

[0057] FIG. 3 is a perspective view of a cable-type battery according to the present invention, FIG. 4 is a cross-sectional view taken along B-B' of FIG. 3, FIG. 5 is a perspective view and cross-sectional view of a negative electrode-separator composite wound in a spiral shape, and FIG. 6 is an exploded perspective view of the negative electrode-separator composite.

[0058] The cable-type battery according to the present invention has a horizontal cross-section of a predetermined shape and may have a linear structure that is elongated in the longitudinal direction relative to the horizontal cross-section. The cable-type battery according to the present invention may be flexible and may be freely deformed. Here, the term "predetermined shape" means that the shape is not specifically limited, and any shape that does not impair the essence of the present invention is possible.

[0059] Referring to FIGS. 3 to 6, the cable-type battery (1000) according to the present invention comprises a metal support (100), a first positive electrode (200) wound on the outer surface of the metal support (100), a negative electrode-separator composite (301) wound on the outer surface of the first positive electrode (200), a second positive electrode (600) wound on the outer surface of the negative electrode-separator composite (301), and a case (700) covering the outer surface of the second positive electrode (600).

[0060] The cable-type battery (1000) according to the present invention is configured such that a negative electrode-separator composite (301) is disposed between a first positive electrode (200) and a second positive electrode (600) to form an integrated structure in which a negative electrode and a separator are bonded, and the negative electrode-separator composite (301) is configured such that the first separator (300), the negative electrode (400), and the second separator (500) are bonded together.

[0061] That is, the first separator (300), the cathode (400), and the second separator (500) are sequentially stacked so that the first surface of the first separator (300) and the cathode (400) are bonded, and the second surface of the cathode (400), which is opposite to the first surface, is bonded to the second separator (500).

[0062] Referring to FIG. 6, the width (D2) of the first separator (300) and the width (D2) of the second separator (500) may be the same and are formed in a shape wider than the width (D1) of the cathode.

[0063] The first separator (300) includes a first extension (310) that extends beyond the outer periphery of the cathode (400), and the second separator (500) includes a second extension (510) that extends beyond the outer periphery of the cathode (400). The width (D3) of the first extension (310) and the width (D3) of the second extension (510) can be configured to be the same, for example, 2 mm to 3 mm. That is, the first extension (310) and the second extension (510) can be configured to extend 2 mm to 3 mm beyond the outer periphery of the cathode (400).

[0064] Additionally, the first extension part (310) and the second extension part (510) can be heat-fused and bonded together. That is, the cathode (400) is firmly fixed between the first separator (300) and the second separator (500), whose outer edges are heat-fused and bonded together.

[0065] FIG. 7 is a cross-sectional view of a cable-type battery according to the present invention before and after deformation, respectively.

[0066] Referring to FIG. 7, FIG. 7 (a) is a vertical cross-sectional view of the cable-type battery according to the present invention before deformation, and FIG. 7 (b) is a vertical cross-sectional view of the cable-type battery after deformation so that it is bent.

[0067] In the cable-type battery according to the present invention, the negative electrode (400) is embedded between the first separator (300) and the second separator (500), so that even if the cable-type battery is bent as in FIG. 7 (b), the negative electrode (400) does not come into direct contact with at least one of the first positive electrode (200) and the second positive electrode (600).

[0068] As such, since the present invention has the negative electrode interposed and fixed between the separators, even if the two ends of the negative electrode-separator composite are not fixed and are spirally wound to manufacture a cable-type battery, it is possible to prevent the negative electrode from shifting position and coming into direct contact with the positive electrode during use of the cable-type battery.

[0069] The first anode (200) comprises a first anode current collector (210) and a first anode active material layer (220) formed on one side of the first anode current collector (210), and the second anode (600) comprises a second anode current collector (610) and a second anode active material layer (620) formed on one side of the second anode current collector (610), and is composed of a single-sided electrode. The first anode active material layer (220) is formed on the side facing the first separator (300) among the outer surfaces of the first anode current collector (210), and the second anode active material layer (620) is formed on the side facing the second separator (500) among the outer surfaces of the second anode current collector (610).

[0070] A polymer film layer may be further included on the outer surface of the first positive current collector (210) where the first positive active material layer (220) is not formed in the first positive electrode (200) and on the outer surface of the second positive current collector (610) where the second positive active material layer (620) is not formed in the second positive electrode (600).

[0071] The above polymer film layer improves the flexibility of the cable-type battery by preventing electrode disconnection from external stress, such as bending or twisting, when the sheet-type first positive current collector (210) and second positive current collector (610) are metal.

[0072] The polymer film layer may be formed from any one selected from the group consisting of polyolefin, polyester, polyimide, and polyamide, or a mixture of two or more of these, but is not limited thereto.

[0073] The cathode (400) is composed of a double-sided electrode having a first cathode active material layer (410) and a second cathode active material layer (420) formed on each side of the cathode current collector (430).

[0074] Meanwhile, if external forces such as bending or twisting are applied to a cable-type battery, the electrode active material layer may detach from the electrode current collector. Therefore, a large amount of binder is incorporated into the electrode active material layer to ensure electrode flexibility. However, this large amount of binder can swell due to the electrolyte and easily detach from the electrode current collector, which may lead to a degradation in the performance of the cable-type battery.

[0075] Accordingly, to improve the adhesion between the electrode active material layer and the electrode current collector, at least one of the first positive current collector, the negative current collector, and the second positive current collector may further include a primer coating layer composed of a conductive material and a binder.

[0076] The above conductive material may include any one selected from the group consisting of carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, and graphene, or a mixture of two or more of these.

[0077] The above binder is polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polybutyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate copolymer, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate. It may be any one selected from the group consisting of propionate), cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl cellulose, styrene-butadiene rubber, acrylonitrile-styrene-butadiene copolymer, and polyimide, or a mixture of two or more of these.

[0078] A lithium-ion supply core containing an electrolyte may be formed in a space formed inside the metal support. The lithium-ion supply core may include a gel-type polymer electrolyte, a liquid electrolyte, and a porous carrier.

[0079] Meanwhile, in order to prevent a short circuit from occurring when a cable-type battery comes into contact with a conductive electrical component, an insulating tube (800) may be further added to the outer surface of the case (700).

[0080] The insulating tube (800) may be formed on the outer surface of the case (700) as an insulator to protect the electrode from moisture in the air and external shocks, or it may be formed on the outer surface of the second anode (600) by omitting the case (700). The insulating tube (800) may use a conventional polymer resin that includes a moisture barrier layer. In this case, aluminum or liquid crystal polymers with excellent moisture barrier performance may be used as the moisture barrier layer, and PET, PVC, HDPE, or epoxy resin may be used as the polymer resin.

[0081] The present invention provides a method for manufacturing a cable-type battery.

[0082] Specifically, the method includes a first step of winding a first anode (200) onto a metal support (100), a second step of winding a cathode-separator composite (301) onto the first anode (200), a third step of winding a second anode (600) onto the cathode-separator composite (301), and a fourth step of wrapping the outer surface of the second anode (600) with a case (700).

[0083] The cathode-separator composite (301) comprises a first separator (300), a cathode (400), and a second separator (500), and the first separator (300), the cathode (400), and the second separator (500) are bonded together to form an integrated form.

[0084] The first separator (300) and the second separator (500) each include a first extension (310) and a second extension (510) that extend beyond the outer periphery of the cathode (400), and the first extension (310) and the second extension (510) are bonded to each other with the cathode (400) embedded between them, so that the cathode (400) is accommodated between the first separator (300) and the second separator (500).

[0085] Additionally, after the above fourth step, a fifth step is included in which an insulating tube (800) is further added to the outer surface of the case (700).

[0086] The present invention manufactures a cable-type battery by interposing a cathode between a first separator and a second separator, and manufacturing a cathode-separator composite by heat-fusion of an extension of the first separator and an extension of the second separator. The process of manufacturing the cathode-separator composite may be carried out prior to the second step, either prior to the first step or after the first step.

[0087] The present invention provides a safe cable-type battery with an improved internal short-circuit prevention effect by adding a cathode-separator composite by winding it spirally between a first anode (200) and a second anode (600), thereby preventing the cathode from coming into direct contact with at least one of the first anode (200) and the second anode (600).

[0088]

[0089] A person skilled in the art to which the present invention pertains would be able to perform various applications and modifications within the scope of the present invention based on the above content.

[0090]

[0091] (Explanation of symbols)

[0092] 100: Metal support

[0093] 200: First anode

[0094] 210: First positive current collector

[0095] 220: First positive active material layer

[0096] 300: First separator

[0097] 301: Cathode-separator composite

[0098] 310: First extension

[0099] 400: Cathode

[0100] 410: First cathode active material layer

[0101] 420: Second cathode active material layer

[0102] 430: Cathode current collector

[0103] 500: Second separator

[0104] 510: 2nd extension

[0105] 600: Second anode

[0106] 610: Second positive current collector

[0107] 620: Second positive active material layer

[0108] 700: Case

[0109] 800: Insulation tube

[0110] 1000: Cable-type battery

[0111]

[0112]

Claims

1. Metal support; A first anode wound on the outer surface of the above metal support; A cathode-separator composite wound on the outer surface of the first anode; A second anode wound on the outer surface of the above cathode-separator composite; and A case covering the outer surface of the second anode; Includes, The above-mentioned cathode-separator composite is a cable-type battery in which a first separator, a cathode, and a second separator are bonded together.

2. In Paragraph 1, A cable-type battery in which the width of the first separator and the width of the second separator are wider than the width of the negative electrode.

3. In Paragraph 1, The first separator and the second separator each include a first extension and a second extension that extend beyond the outer periphery of the cathode, and A cable-type battery in which the first extension part and the second extension part are bonded to each other.

4. In Paragraph 3, A cable-type battery configured such that the first extension part and the second extension part extend 2 mm to 3 mm beyond the outer periphery of the negative electrode.

5. In Paragraph 1, A cable-type battery in which the first extension part and the second extension part are heat-fused and bonded to each other.

6. In Paragraph 1, A cable-type battery having an additional insulating tube added to the outer surface of the above case.

7. In Paragraph 1, The above first positive and the above second positive are a cable-type battery comprising a single-sided electrode including a positive current collector and a positive active material layer formed on one side of the positive current collector.

8. In Paragraph 1, The above-mentioned negative electrode is a cable-type battery comprising a negative current collector and a double-sided electrode in which a negative active material layer is formed on each side of the negative current collector.

9. A method for manufacturing a cable-type battery according to any one of claims 1 to 8, wherein A first step of winding a first anode onto a metal support; A second step of winding a cathode-separator composite onto the first anode; A third step of winding a second anode onto the above cathode-separator composite; and A fourth step of wrapping the outer surface of the second anode with a case; A method for manufacturing a cable-type battery including 10. In Paragraph 9, The above cathode-separator composite comprises a first separator, a cathode, and a second separator, and A method for manufacturing a cable-type battery in which the first separator, the negative electrode, and the second separator are bonded together to form an integrated form.

11. In Paragraph 10, The first separator and the second separator each include a first extension and a second extension that extend beyond the outer periphery of the cathode, and A method for manufacturing a cable-type battery in which the first extension part and the second extension part are bonded to each other, and the negative electrode is accommodated between the first separator and the second separator.

12. In Paragraph 9, A method for manufacturing a cable-type battery comprising, after the above-mentioned fourth step, a fifth step of adding an insulating tube to the outer surface of the case.

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