Rechargeable battery and rechargeable battery manufacturing method

Abstract

The present invention relates to a secondary battery and a method for manufacturing a secondary battery. The secondary battery according to the present invention comprises an electrode assembly in which electrodes and separators are alternately stacked and wound, a battery case that accommodates the electrode assembly and an electrolyte, and a fixing tape that is adhered to the outer surface of the electrode assembly to prevent unwinding. When the fixing tape is impregnated with the electrolyte, the fixing force that suppresses unwinding is weakened, causing the electrode assembly to unwind and fill the space between the battery case and the electrode assembly.

Description

Technology Field

[0001] The present invention relates to a secondary battery and a method for manufacturing a secondary battery. Background Technology

[0003] Unlike primary batteries, secondary batteries are rechargeable and are currently the subject of extensive research and development due to their potential for miniaturization and high capacity. As technological development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rising rapidly.

[0004] Secondary batteries are classified into coin batteries, cylindrical batteries, prismatic batteries, and pouch batteries according to the shape of the battery case. In secondary batteries, the electrode assembly mounted inside the battery case is a rechargeable power generation device consisting of a laminated structure of electrodes and separators.

[0005] Electrode assemblies can be roughly classified into a jelly-roll type, which is wound with a separator interposed between sheet-type positive and negative electrodes coated with active material; a stack type, which is sequentially stacked with multiple positive and negative electrodes interposed with a separator; and a stack / folding type, which is wound with unit cells of the stack type wrapped in a long separating film.

[0006] Among these, jelly roll type electrode assemblies are widely used because they have the advantages of being easy to manufacture and having a high energy density per unit weight.

[0007] Cylindrical batteries containing jelly roll-type electrode assemblies use finishing tapes made of PET or PP materials to prevent the jelly roll from unraveling and to protect against external damage.

[0008] Jelly rolls secured with PET or PP sealing tape have a problem moving inside the cell if there is empty space within the cell. Prior art literature

[0010] Korean Published Patent No. 10-2016-0010121 The problem to be solved

[0011] One aspect of the present invention is to provide a secondary battery and a method for manufacturing a secondary battery capable of preventing flow of an electrode assembly.

[0012] Another aspect of the present invention is to provide a secondary battery capable of reducing battery resistance and a method for manufacturing a secondary battery. means of solving the problem

[0014] A secondary battery according to an embodiment of the present invention comprises an electrode assembly in which an electrode and a separator are alternately stacked and wound, a battery case in which the electrode assembly and an electrolyte are accommodated, and a fixing tape attached to the outer surface of the electrode assembly to prevent unwinding, wherein the fixing force of the fixing tape that suppresses unwinding is weakened when impregnated with the electrolyte, so that the winding of the electrode assembly is unwound and the space between the battery case and the electrode assembly can be filled.

[0015] Meanwhile, a method for manufacturing a secondary battery according to an embodiment of the present invention comprises a winding process in which electrodes and separators are alternately stacked and wound to form an electrode assembly, a tape attachment process in which a fixing tape is attached to the outer surface of the electrode assembly to prevent unwinding, and a receiving process in which the electrode assembly and an electrolyte are received inside a battery case, wherein in the tape attachment process, the fixing tape is used such that the fixing force suppressing unwinding is weakened when impregnated with the electrolyte, and in the receiving process, the fixing force of the fixing tape is weakened when the electrolyte is received, thereby allowing the electrode assembly to be unwound and the space between the battery case and the electrode assembly to be filled. Effects of the invention

[0017] According to the present invention, when a fixing tape adhered to the outer surface of an electrode assembly to prevent unwinding is impregnated with an electrolyte, the fixing force that suppresses unwinding is weakened, and the fixing force that suppresses unwinding can be released. Accordingly, as the winding of the electrode assembly is unwound and the space between the battery case and the electrode assembly is filled, movement of the electrode assembly can be prevented.

[0018] At this time, the negative electrode is wound on the outermost surface of the electrode assembly, and when the winding of the electrode assembly is unwound, it comes into contact with the inner surface of the battery case, so that the battery resistance can be significantly reduced. Brief explanation of the drawing

[0020] FIG. 1 is a perspective view showing a secondary battery according to one embodiment of the present invention. FIG. 2 is a cross-sectional view exemplarily showing the state before the winding of an electrode assembly is unwound in a secondary battery according to one embodiment of the present invention. FIG. 3 is a cross-sectional view exemplarily showing the state in which the winding of an electrode assembly is unwound in a secondary battery according to one embodiment of the present invention. FIG. 4 is a cross-sectional view exemplarily showing the state before the winding of an electrode assembly is unwound in a secondary battery according to another embodiment of the present invention. FIG. 5 is a cross-sectional view exemplarily showing the state in which the winding of an electrode assembly is unwound in a secondary battery according to another embodiment of the present invention. FIG. 6 is a perspective view showing a secondary battery according to another embodiment of the present invention. FIG. 7 is a cross-sectional view exemplarily showing the state before the winding of an electrode assembly is unwound in a secondary battery according to another embodiment of the present invention. Figure 8 is a photograph showing the state of the fixing tape before it reacts with the electrolyte in the secondary battery of the present invention. Figure 9 is a photograph showing the state in which the fixing tape reacts with the electrolyte and dissolves in the secondary battery of the present invention. Specific details for implementing the invention

[0021] The objects, specific advantages, and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings. It should be noted that in assigning reference numerals to the components of each drawing in this specification, the same components are assigned the same number whenever possible, even if they are shown in different drawings. Furthermore, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Also, in describing the present invention, detailed descriptions of related known technologies that could unnecessarily obscure the essence of the invention are omitted.

[0023] A secondary battery according to one embodiment

[0025] FIG. 1 is an exploded perspective view showing a secondary battery according to an embodiment of the present invention, FIG. 2 is a cross-sectional view exemplarily showing the state before the winding of the electrode assembly in the secondary battery according to an embodiment of the present invention is unwound, and FIG. 3 is a cross-sectional view exemplarily showing the state in which the winding of the electrode assembly in the secondary battery according to an embodiment of the present invention is unwound. Here, in FIG. 2 and 3, the cap is omitted from the illustration.

[0026] Referring to FIGS. 1 to 3, a secondary battery (100) according to one embodiment of the present invention comprises an electrode assembly (110) in which an electrode (113) and a separator (114, 115) are alternately stacked and wound, a battery case (120) in which the electrode assembly (110) and an electrolyte are received, and a fixing tape (140) attached to the outer surface of the electrode assembly (110).

[0028] Hereinafter, with reference to FIGS. 1 to 3, a secondary battery (100) which is an embodiment of the present invention will be described in more detail.

[0029] Referring to FIGS. 1 to 3, the electrode assembly (110) is a power generation element capable of charging and discharging, and forms a structure in which an electrode (113) and a separator (114, 115) are assembled and alternately stacked. Here, the electrode assembly (110) may be formed in a wound form in which the electrode (113) and the separator (114, 115) are alternately assembled. At this time, the electrode assembly (110) may be wound in a cylindrical shape wound around a central axis (C).

[0030] The electrode (113) may include an anode (112) and a cathode (111). And, the separator (114, 115) separates the anode (112) and the cathode (111) to electrically insulate them.

[0032] The positive electrode (112) may include a positive electrode current collector (112a) and a positive electrode active material (112b) provided on one side of the positive electrode current collector (112a). At this time, the positive electrode (112) may include a positive electrode non-layer, which is an area where the positive electrode active material (112b) is not laminated.

[0033] The positive current collector (112a) can be made of, for example, aluminum foil.

[0034] The positive active material (112b) may be composed of lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or compounds and mixtures containing one or more of these.

[0036] The cathode (111) may include a cathode current collector (111a) and a cathode active material (111b) provided on one side of the cathode current collector (111a). At this time, the cathode (111) may include a cathode non-layer, which is an area where the cathode active material (111b) is not laminated.

[0037] The negative current collector (111a) can be made of, for example, a copper foil made of copper (Cu) material.

[0038] The negative electrode active material (111b) may be composed of, for example, artificial graphite, lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound, or an alloy thereof. At this time, the negative electrode active material (111b) may further include, for example, non-graphite-based SiO (silica) or SiC (silicon carbide).

[0039] The negative electrode (111) is wound on the outermost surface of the electrode assembly (110) so that when the electrode assembly (110) is unwound, it can come into contact with the inner surface of the battery case (120). At this time, the negative electrode current collector (111a) of the negative electrode (111) is positioned on the outermost surface when the electrode assembly (110) is wound, so that when the electrode assembly (110) is unwound, it can come into contact with the inner surface of the battery case (120). Accordingly, the battery resistance can be reduced. That is, when the negative electrode tab (132) alone comes into contact with the inner surface of the battery case (120), a lot of resistance is applied to the negative electrode tab (132), and this causes problems such as high heat generation and the negative electrode tab (132) melting or disconnecting. In contrast, the present invention has a negative electrode current collector (111a) positioned on the outermost surface of the electrode assembly (110) and comes into contact with the inner surface of the battery case (120) when the winding is unwound, thereby significantly reducing resistance.

[0041] The separator (114, 115) is made of an insulating material and can insulate between the positive electrode (112) and the negative electrode (111).

[0042] Additionally, the separator (114, 115) may be a multilayer film made of, for example, microporous polyethylene, polypropylene, or a combination thereof, or a polymer film for solid polymer electrolytes or gel-type polymer electrolytes such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, or polyvinylidene fluoride hexafluoropropylene copolymer.

[0044] The battery case (120) may have a receiving portion (121a) that is open to the top and accommodates the electrode assembly (110). At this time, the battery case (120) may be formed in a cylindrical shape, for example.

[0045] Additionally, the battery case (120) may be formed with an open upper portion (121a) for receiving the electrode assembly (110) and the electrolyte. At this time, the secondary battery (100) of one embodiment of the present invention may include a top cap (160) covering the upper portion of the battery case (120).

[0046] Here, the inner surface of the battery case (120) may include a metal material.

[0047] And, the battery case (120) is connected to the negative electrode (111) of the electrode assembly (110) to form the negative electrode (111), and the top cap (160) is connected to the positive electrode (112) of the electrode assembly (110) to form the positive electrode (112), and the battery case (120) and the top cap (160) can be insulated from each other.

[0048] Meanwhile, an insulating layer is provided between the bottom surface of the battery case (120) and the lower part of the electrode assembly (110) to insulate the electrode assembly (110) from the battery case (120). At this time, a negative electrode tab (132) connected to the negative electrode (111) of the electrode assembly (110) can penetrate the insulating layer and come into contact with the bottom surface of the battery case (120).

[0050] The electrode tab (130) is attached to the electrode (113) and is electrically connected to the electrode (113).

[0051] The electrode tab (130) may include an anode tab (131) attached to the anode (112) and a cathode tab (132) attached to the cathode (111).

[0052] Meanwhile, the positive electrode tab (131) is formed in the direction where the cap (30) is located, which is the upper direction when referring to FIG. 1, and the negative electrode tab (132) can be positioned toward the bottom surface of the receiving portion (121a) of the battery case (120), which is the lower direction.

[0054] The electrolyte may include salt, solvent, and additives.

[0055] Salt may include lithium salts. In this case, the lithium salts are LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB10Cl 10 It may include at least one of LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate, imide, LiTFSI, LiFSI, and LiBOB.

[0056] The solvent may include at least one of the following aprotic organic solvents: N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butylolactone, 1,2-dimethoxyethane, tetrahydroxyfranc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolone, formamide, dimethylformamide, dioxolone, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxymethane, dioxolone derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ether, methyl propionate, ethyl propionate, etc.

[0057] The additive may include at least one of VC (vinylene carbonate), FB (fluorobenzene), VC (vinylene carbonate), FEC (fluoroethylene carbonate), PS (propane sulfone), Esa (ethylene sulfite), and LiBF4.

[0059] The fixing tape (140) can be adhered to the outer surface of the electrode assembly (110) to prevent unwinding.

[0060] When the fixing tape (140) is impregnated with the electrolyte, the fixing force that prevents the electrode assembly (110) from unwinding is weakened, allowing the electrode assembly (110) to unwind and fill the space between the battery case (120) and the electrode assembly (110). At this time, the fixing tape (140) contains a reactive substance that reacts with the electrolyte and dissolves, so that when the electrolyte is received, the reactive substance dissolves and the fixing force that prevents the unwinding is released. Accordingly, the electrode assembly (110) unwinds and fills the space (E) between the battery case (120) and the electrode assembly (110), thereby preventing movement of the electrode assembly (110). At this time, the gap between the center (I) of the electrode assembly (110) and the outer edge (O) of the winding can become wider as the electrode assembly (110) unwinds.

[0061] The reactant material may consist of at least one of OPS (oriented polystyrene), TPU (Thermo Plastic Polyurethane), or GPPS (General Purpose Polystyrene) that reacts with the electrolyte and dissolves.

[0062] The fixing tape (140) may include a base film (141) and an adhesive layer (142) provided on one side of the base film (141).

[0063] The adhesive layer (142) contains a reactive material, so that when the electrolyte is contained inside the battery case in which the electrode assembly (110) is housed, it dissolves and the adhesive force is eliminated. Accordingly, the inhibition of unwinding of the electrode assembly (110) through the fixing tape (140) can be released.

[0064] Meanwhile, the fixing tape (140) may be adhered to the upper and lower parts of the outer surface of the electrode assembly (110), for example. Here, the fixing tape (140) may be adhered along the width direction of the electrode assembly (110). At this time, the fixing tape (140) may be adhered to the wound end and the periphery of the wound end of the electrode assembly (110) on the outer surface of the electrode assembly (110), or may be adhered by wrapping around the outer surface.

[0065] Additionally, the fixing tape (140) may be adhered to the upper and lower portions of the outer surface of the electrode assembly (110) as another example. Here, the fixing tape (140) may be adhered along the longitudinal direction of the electrode assembly (110). In this case, the fixing tape (140) may be formed in a rectangular shape and attached to the wound end of the electrode assembly (110) and the periphery of the wound end.

[0067] A secondary battery (100) according to one embodiment of the present invention configured as described above includes a reactive substance that reacts with an electrolyte and dissolves in a fixing tape (140) that is adhered to the outer surface of an electrode assembly (110) to prevent unwinding. Accordingly, when the electrolyte is received, the reactive substance dissolves and the fixing force that suppresses unwinding is released, causing the winding of the electrode assembly (110) to unwind and fill the space (E) between the battery case (120) and the electrode assembly (110), thereby preventing movement of the electrode assembly (110).

[0068] At this time, the negative electrode (111) is wound on the outermost surface of the electrode assembly (110), so that when the winding of the electrode assembly (110) is unwound, it can come into contact with the inner surface of the battery case (120). Accordingly, the battery resistance can be significantly reduced.

[0070] Secondary battery according to another embodiment

[0072] A secondary battery according to another embodiment will be described below.

[0073] FIG. 4 is a cross-sectional view exemplarily showing the state before the winding of an electrode assembly in a secondary battery according to another embodiment of the present invention is unwound, and FIG. 5 is a cross-sectional view exemplarily showing the state after the winding of an electrode assembly in a secondary battery according to another embodiment of the present invention is unwound. Here, in FIG. 4 and 5, the cap is omitted from the illustration.

[0074] Referring to FIGS. 4 and 5, a secondary battery according to another embodiment of the present invention comprises an electrode assembly (110) in which electrodes (113) and separators (114, 115) are alternately stacked and wound, a battery case (120) in which the electrode assembly (110) and an electrolyte are received, and a fixing tape (240) attached to the outer surface of the electrode assembly (110).

[0075] The secondary battery (200) according to another embodiment of the present invention differs from the secondary battery according to the first embodiment described above in that the part where the reactant is located on the fixing tape (240). Therefore, in this embodiment, details that overlap with the first embodiment are omitted or described briefly, and the description focuses on the differences.

[0077] More specifically, the electrode assembly (110) is a power generation element capable of charging and discharging, and forms a structure in which electrodes (113) and separators (114, 115) are assembled and alternately stacked. Here, the electrode assembly (110) may be formed in a wound form in which electrodes (113) and separators (114, 115) are alternately assembled. At this time, the electrode assembly (110) may be wound in a cylindrical shape wound around a central axis (C).

[0078] The electrode (113) may include an anode (112) and a cathode (111). And, the separator (114, 115) separates the anode (112) and the cathode (111) to electrically insulate them.

[0079] The positive electrode (112) may include a positive electrode current collector (112a) and a positive electrode active material (112b) provided on one side of the positive electrode current collector (112a). At this time, the positive electrode (112) may include a positive electrode non-layer, which is an area where the positive electrode active material (112b) is not laminated.

[0080] The cathode (111) may include a cathode current collector (111a) and a cathode active material (111b) provided on one side of the cathode current collector (111a). At this time, the cathode (111) may include a cathode non-layer, which is an area where the cathode active material (111b) is not laminated.

[0081] The negative current collector (111a) can be made of, for example, a copper foil made of copper (Cu) material.

[0082] The negative electrode (111) is wound on the outermost surface of the electrode assembly (110) so that when the electrode assembly (110) is unwound, it can come into contact with the inner surface of the battery case (120). At this time, the negative electrode current collector (111a) of the negative electrode (111) is positioned on the outermost surface when the electrode assembly (110) is wound, so that when the electrode assembly (110) is unwound, it can come into contact with the inner surface of the battery case (120). Accordingly, the battery resistance can be reduced. That is, when the negative electrode tab (132) alone comes into contact with the inner surface of the battery case (120), a lot of resistance is applied to the negative electrode tab (132), and this causes problems such as high heat generation and the negative electrode tab (132) melting or disconnecting. In contrast, the present invention has a negative electrode current collector (111a) positioned on the outermost surface of the electrode assembly (110) and comes into contact with the inner surface of the battery case (120) when the winding is unwound, thereby significantly reducing resistance.

[0083] The separator (114, 115) is made of an insulating material and can insulate between the positive electrode (112) and the negative electrode (111).

[0085] The battery case (120) may have a receiving portion formed at the top that is open to accommodate the electrode assembly (110). At this time, the battery case (120) may be formed, for example, in a cylindrical shape.

[0086] Additionally, the battery case (120) may be formed with an open upper portion (121a) for receiving the electrode assembly (110) and the electrolyte. At this time, the secondary battery (200), which is another embodiment of the present invention, may include a top cap covering the upper portion of the battery case (120). Here, the inner surface of the battery case (120) may be made of a metal material.

[0087] The battery case (120) is connected to the negative electrode (111) of the electrode assembly (110) to form the negative electrode (111), and the top cap (160) is connected to the positive electrode (112) of the electrode assembly (110) to form the positive electrode (112), and the battery case (120) and the top cap (160) can be insulated from each other.

[0088] Meanwhile, an insulating layer is provided between the bottom surface of the battery case (120) and the lower part of the electrode assembly (110) to insulate the electrode assembly (110) from the battery case (120). At this time, a negative electrode tab (132) connected to the negative electrode (111) of the electrode assembly (110) can penetrate the insulating layer and come into contact with the bottom surface of the battery case (120).

[0090] The electrode tab (130) is attached to the electrode (113) and is electrically connected to the electrode (113).

[0091] The electrode tab (130) may include an anode tab (131) attached to the anode (112) and a cathode tab (132) attached to the cathode (111).

[0093] The fixing tape (240) can be adhered to the outer surface of the electrode assembly (110) to prevent unwinding.

[0094] When the fixing tape (240) is impregnated with the electrolyte, the fixing force that prevents the electrode assembly (110) from unwinding is weakened, so that the electrode assembly (110) can be unwound and the space between the battery case (120) and the electrode assembly (110) can be filled. At this time, the fixing tape (240) contains a reactive substance that reacts with the electrolyte and dissolves, so that when the electrolyte is received, the reactive substance dissolves and the fixing force that prevents the unwinding can be released. Accordingly, the electrode assembly (110) can be unwound and the space (E) between the battery case (120) and the electrode assembly (110) can be filled, thereby preventing movement of the electrode assembly (110).

[0095] Here, the reactant may consist of at least one of OPS (oriented polystyrene), TPU (Thermo Plastic Polyurethane), or GPPS (General Purpose Polystyrene) that reacts with the electrolyte and dissolves.

[0096] The fixing tape (240) may include a base film (241) and an adhesive layer (242) provided on one side of the base film (241).

[0097] As the base film (241) dissolves when receiving an electrolyte containing a reactant, the inhibition of unwinding of the electrode assembly (110) through the fixing tape (240) can be released.

[0098] Meanwhile, the fixing tape (240) can be adhered to the upper and lower parts of the outer surface of the electrode assembly (110).

[0100] A secondary battery according to another embodiment

[0102] A secondary battery according to another embodiment will be described below.

[0103] FIG. 6 is a perspective view showing a secondary battery according to another embodiment of the present invention, and FIG. 7 is a cross-sectional view exemplarily showing the state before the winding of the electrode assembly in the secondary battery according to another embodiment of the present invention is unwound.

[0104] Referring to FIGS. 6 and 7, a secondary battery (300) according to another embodiment of the present invention comprises an electrode assembly (110) in which electrodes (113) and separators (114, 115) are alternately stacked and wound, a battery case (120) in which the electrode assembly (110) and an electrolyte are received, and a fixing tape (340) attached to the outer surface of the electrode assembly (110).

[0105] The secondary battery (300) according to another embodiment of the present invention differs in the configuration of the fixing tape (340) when compared to the secondary battery according to the first embodiment and other embodiments described above. Therefore, in this embodiment, details that overlap with the first embodiment and other embodiments are omitted or described briefly, and the description focuses on the differences.

[0107] More specifically, the electrode assembly (110) is a power generation element capable of charging and discharging, and forms a structure in which electrodes (113) and separators (114, 115) are assembled and alternately stacked. Here, the electrode assembly (110) may be formed in a wound form in which electrodes (113) and separators (114, 115) are alternately assembled. At this time, the electrode assembly (110) may be wound in a cylindrical shape wound around a central axis (C).

[0108] The electrode (113) may include an anode (112) and a cathode (111). And, the separator (114, 115) separates the anode (112) and the cathode (111) to electrically insulate them.

[0109] The positive electrode (112) may include a positive electrode current collector (112a) and a positive electrode active material (112b) provided on one side of the positive electrode current collector (112a). At this time, the positive electrode (112) may include a positive electrode non-layer, which is an area where the positive electrode active material (112b) is not laminated.

[0110] The cathode (111) may include a cathode current collector (111a) and a cathode active material (111b) provided on one side of the cathode current collector (111a). At this time, the cathode (111) may include a cathode non-layer, which is an area where the cathode active material (111b) is not laminated.

[0111] The negative current collector (111a) can be made of, for example, a copper foil made of copper (Cu) material.

[0112] The negative electrode (111) is wound on the outermost surface of the electrode assembly (110) so that when the electrode assembly (110) is unwound, it can come into contact with the inner surface of the battery case (120). At this time, the negative electrode current collector (111a) of the negative electrode (111) is positioned on the outermost surface when the electrode assembly (110) is wound, so that when the electrode assembly (110) is unwound, it can come into contact with the inner surface of the battery case (120). Accordingly, the battery resistance can be reduced. That is, when the negative electrode tab (132) alone comes into contact with the inner surface of the battery case (120), a lot of resistance is applied to the negative electrode tab (132), which causes problems such as high heat generation and the negative electrode tab (132) melting or disconnecting. In contrast, the present invention has a negative electrode current collector (111a) positioned on the outermost surface of the electrode assembly (110) and comes into contact with the inner surface of the battery case (120) when the winding is unwound, thereby significantly reducing resistance. The separator (114, 115) is made of an insulating material and can insulate between the positive electrode (112) and the negative electrode (111).

[0114] The battery case (120) may have a receiving portion formed at the top that is open to accommodate the electrode assembly (110). At this time, the battery case (120) may be formed, for example, in a cylindrical shape.

[0115] Additionally, the battery case (120) may be formed with an open upper portion (121a) for receiving the electrode assembly (110) and the electrolyte. At this time, the secondary battery (200), which is another embodiment of the present invention, may include a top cap (160) covering the upper portion of the battery case (120). Here, the inner surface of the battery case (120) may be made of a metal material.

[0116] The battery case (120) is connected to the negative electrode (111) of the electrode assembly (110) to form the negative electrode (111), and the top cap (160) is connected to the positive electrode (112) of the electrode assembly (110) to form the positive electrode (112), and the battery case (120) and the top cap (160) can be insulated from each other.

[0117] Meanwhile, an insulating layer is provided between the bottom surface of the battery case (120) and the lower part of the electrode assembly (110) to insulate the electrode assembly (110) from the battery case (120). At this time, a negative electrode tab (132) connected to the negative electrode (111) of the electrode assembly (110) can penetrate the insulating layer and come into contact with the bottom surface of the battery case (120).

[0119] The electrode tab (130) is attached to the electrode (113) and is electrically connected to the electrode (113).

[0120] The electrode tab (130) may include an anode tab (131) attached to the anode (112) and a cathode tab (132) attached to the cathode (111).

[0122] The fixing tape (340) can be adhered to the outer surface of the electrode assembly (110) to prevent unwinding.

[0123] When the fixing tape (340) is impregnated with the electrolyte, the fixing force that prevents the electrode assembly (110) from unwinding is weakened, so that the electrode assembly (110) unwinds and the space between the battery case (120) and the electrode assembly (110) is filled, thereby preventing movement of the electrode assembly (110).

[0124] Meanwhile, for example, when the fixing tape (340) is impregnated with the electrolyte, the electrolyte seeps between the fixing tape (340) and the electrode assembly (110), reducing the adhesive area and thus reducing the adhesive force. Also, as another example, when the fixing tape (340) is impregnated with the electrolyte, the fixing tape (340) expands and the adhesive force may be reduced. Meanwhile, when the electrode assembly (110) is charged while the fixing tape (340) is impregnated with the electrolyte and the adhesive force is weakened, the electrode assembly (110) expands, and the fixing force of the fixing tape (340) can be released more effectively.

[0125] The fixing tape (340) may include a base film (341) and an adhesive layer (342) provided on one side of the base film (341).

[0126] Additionally, the adhesive layer (342) of the fixing tape (340) can have its adhesive strength reduced by using a low-adhesion adhesive. Accordingly, when impregnated with an electrolyte, the adhesive strength is reduced more effectively, making it easier to release the fixing force that prevents the electrode assembly (110) from unwinding.

[0127] Here, the fixing tape (340) may, for example, have an adhesive layer (342) made of an acrylic adhesive that is a low-adhesion adhesive. At this time, the adhesive layer (342) may further include a curing agent to further reduce the adhesive strength.

[0128] Meanwhile, the fixing tape (340) can reduce the adhesive strength by reducing the thickness of the adhesive layer (342) so that the adhesive strength is low, as another example. In this case, for example, the thickness of the adhesive layer (342) can be reduced by more than 50%.

[0129] In addition, the fixing tape (340) may further include a curing agent in the adhesive layer (342) to lower the adhesive strength as another example. That is, the adhesive layer (342) may be cured through the curing agent, thereby lowering the adhesive strength. At this time, the curing agent may be, for example, an isocyanate. Meanwhile, the fixing tape (340) may be adhered to the upper and lower parts of the outer surface of the electrode assembly (110), for example. Here, the fixing tape (340) may be adhered along the longitudinal direction of the electrode assembly (110). At this time, the fixing tape (340) may be formed in a rectangular shape and attached to the winding end of the electrode assembly (110) and the periphery of the winding end.

[0130] Additionally, the fixing tape (340) can be adhered to the upper and lower parts, respectively, on the outer surface of the electrode assembly (110) as another example. Here, the fixing tape (340) can be adhered along the width direction of the electrode assembly (110).

[0132] Meanwhile, a battery pack can be configured by including multiple secondary batteries according to one embodiment or another embodiment configured as described above.

[0134] Method for manufacturing a secondary battery according to one embodiment

[0136] Hereinafter, a method for manufacturing a secondary battery, which is an embodiment of the present invention, will be described.

[0137] Referring to FIGS. 1 to 3, a secondary battery manufacturing method according to one embodiment of the present invention includes a winding process in which electrodes (113) and separators (114, 115) are alternately stacked and wound to form an electrode assembly (110), a tape adhesion process in which a fixing tape (140) is adhered to the outer surface of the electrode assembly (110), and a receiving process in which the electrode assembly (110) and the electrolyte are received inside a battery case (120).

[0138] A method for manufacturing a secondary battery according to one embodiment of the present invention relates to a method for manufacturing a secondary battery that manufactures a secondary battery according to one embodiment of the present invention described above.

[0139] Accordingly, in the embodiment of the secondary battery manufacturing method according to one embodiment of the present invention, details that overlap with the secondary battery according to one embodiment of the present invention described above are omitted or described briefly, and the description focuses on the differences.

[0141] More specifically, the winding process can form an electrode assembly (110) by alternately stacking and winding electrodes (113) and separators (114, 115).

[0142] Here, the electrode (113) includes an anode (112) and a cathode (111). At this time, the cathode (111) may include a cathode current collector (111a) and a cathode active material (111b) provided on one side of the cathode current collector (111a).

[0143] During the winding process, the negative electrode (111) can be wound so that it is positioned on the outermost surface of the electrode assembly (110). At this time, more specifically, during the winding process, the negative electrode current collector (111a) can be wound so that it is positioned on the outermost surface of the electrode assembly (110).

[0145] The tape adhesion process can be performed by attaching a fixing tape (140) to the outer surface of the electrode assembly (110) to prevent unwinding.

[0146] A fixing tape (140) can be used in which the fixing force that suppresses the unwinding of the electrode assembly (110) when impregnated with the electrolyte during the tape adhesion process is weakened. In this case, a fixing tape (140) containing a reactive substance that reacts with and dissolves with the electrolyte during the tape adhesion process can be used.

[0147] The tape adhesion process can adhere the fixing tape (140) to the upper and lower parts of the outer surface of the electrode assembly (110).

[0149] The receiving process can accommodate the electrode assembly (110) and the electrolyte inside the battery case (120).

[0150] During the receiving process, when the electrolyte is received, the reactant dissolves and the fixing force of the fixing tape (140) that suppresses unwinding is released, so that the winding of the electrode assembly (110) is unwound and the space between the battery case (120) and the electrode assembly (110) can be filled.

[0151] Additionally, when the winding of the electrode assembly (110) is unwound during the receiving process, the inner surface of the battery case (120) and the negative electrode (111) may come into contact. At this time, when the winding of the electrode assembly (110) is unwound during the receiving process, the inner surface of the battery case (120) containing a metal material and the negative electrode current collector (111a) may come into contact.

[0153] Meanwhile, the tape adhesion process can be applied to the electrode assembly (110) using a fixing tape (140) that includes a base film (141) and a reactive material, and an adhesive layer (142) provided on one side of the base film (141). Accordingly, when the electrolyte is received during the receiving process, the adhesive force is lost as the adhesive layer (142) dissolves, allowing the winding of the electrode assembly (110) to be unwound.

[0155] Method for manufacturing a secondary battery according to another embodiment

[0157] Hereinafter, a method for manufacturing a secondary battery, which is another embodiment of the present invention, will be described.

[0158] Referring to FIGS. 4 and 5, a secondary battery manufacturing method according to another embodiment of the present invention includes a winding process in which electrodes (113) and separators (114, 115) are alternately stacked and wound to form an electrode assembly (110), a tape adhesion process in which a fixing tape (240) is adhered to the outer surface of the electrode assembly (110), and a receiving process in which the electrode assembly (110) and the electrolyte are received inside a battery case (120).

[0159] The method for manufacturing a secondary battery according to another embodiment of the present invention differs from the method for manufacturing a secondary battery according to the first embodiment of the present invention described above in that the part where the reactant is located on the fixing tape (240). Therefore, in this embodiment, details that overlap with the previously described embodiment are omitted or described briefly, and the description focuses on the differences.

[0161] More specifically, the winding process can form an electrode assembly (110) by alternately stacking and winding electrodes (113) and separators (114, 115).

[0162] Here, the electrode (113) includes an anode (112) and a cathode (111). At this time, the cathode (111) may include a cathode current collector (111a) and a cathode active material (111b) provided on one side of the cathode current collector (111a).

[0163] During the winding process, the negative electrode (111) can be wound so that it is positioned on the outermost surface of the electrode assembly (110). At this time, more specifically, during the winding process, the negative electrode current collector (111a) can be wound so that it is positioned on the outermost surface of the electrode assembly (110).

[0165] The tape adhesion process can be performed by attaching a fixing tape (240) to the outer surface of the electrode assembly (110) to prevent unwinding.

[0166] A fixing tape (240) can be used in which the fixing force that suppresses the unwinding of the electrode assembly (110) when impregnated with the electrolyte during the tape adhesion process is weakened.

[0167] At this time, a fixing tape (240) containing a reactive substance that reacts with the electrolyte and dissolves during the tape adhesion process can be used.

[0168] The tape adhesion process can adhere the fixing tape (240) to the upper and lower parts of the outer surface of the electrode assembly (110).

[0170] The receiving process can accommodate the electrode assembly (110) and the electrolyte inside the battery case (120).

[0171] During the receiving process, when the electrolyte is received, the reactant dissolves and the fixing force of the fixing tape (240) that suppresses unwinding is released, so that the winding of the electrode assembly (110) is unwound and the space between the battery case (120) and the electrode assembly (110) can be filled.

[0172] Additionally, when the winding of the electrode assembly (110) is unwound during the receiving process, the inner surface of the battery case (120) and the negative electrode (111) may come into contact. At this time, when the winding of the electrode assembly (110) is unwound during the receiving process, the inner surface of the battery case (120) containing a metal material and the negative electrode current collector (111a) may come into contact.

[0174] Meanwhile, the tape adhesion process can be applied to the electrode assembly (110) using a fixing tape (240) comprising a base film (241) containing a reactive material and an adhesive layer (242) provided on one side of the base film (241). Accordingly, as the base film (241) dissolves when the electrolyte is received during the receiving process, the winding of the electrode assembly (110) can be unwound.

[0176] Method for manufacturing a secondary battery according to another embodiment

[0178] Hereinafter, a method for manufacturing a secondary battery, which is another embodiment of the present invention, will be described.

[0179] Referring to FIGS. 6 and 7, a secondary battery manufacturing method according to another embodiment of the present invention includes a winding process in which electrodes (113) and separators (114, 115) are alternately stacked and wound to form an electrode assembly (110), a tape adhesion process in which a fixing tape (340) is adhered to the outer surface of the electrode assembly (110), and a receiving process in which the electrode assembly (110) and the electrolyte are received inside a battery case (120).

[0180] The method for manufacturing a secondary battery according to another embodiment of the present invention differs in the fixing tape (340) when compared to the method for manufacturing a secondary battery according to the first and other embodiments of the present invention described above. Therefore, in this embodiment, details that overlap with the previously described embodiments are omitted or described briefly, and the description focuses on the differences.

[0182] More specifically, the winding process can form an electrode assembly (110) by alternately stacking and winding electrodes (113) and separators (114, 115).

[0183] Here, the electrode (113) includes an anode (112) and a cathode (111). At this time, the cathode (111) may include a cathode current collector (111a) and a cathode active material (111b) provided on one side of the cathode current collector (111a).

[0184] During the winding process, the negative electrode (111) can be wound so that it is positioned on the outermost surface of the electrode assembly (110). At this time, more specifically, during the winding process, the negative electrode current collector (111a) can be wound so that it is positioned on the outermost surface of the electrode assembly (110).

[0186] The tape adhesion process can be performed by attaching a fixing tape (340) to the outer surface of the electrode assembly (110) to prevent unwinding.

[0187] A fixing tape (340) can be used in which the fixing force that suppresses the unwinding of the electrode assembly (110) when impregnated with the electrolyte during the tape adhesion process is weakened.

[0188] The tape adhesion process can adhere the fixing tape (340) to the upper and lower parts of the outer surface of the electrode assembly (110).

[0190] The receiving process can accommodate the electrode assembly (110) and the electrolyte inside the battery case (120).

[0191] As the fixing force of the fixing tape (340) that suppresses unwinding when receiving the electrolyte during the receiving process weakens, the winding of the electrode assembly (110) is unwound and the space between the battery case (120) and the electrode assembly (110) can be filled.

[0192] Additionally, when the winding of the electrode assembly (110) is unwound during the receiving process, the inner surface of the battery case (120) and the negative electrode (111) may come into contact. At this time, when the winding of the electrode assembly (110) is unwound during the receiving process, the inner surface of the battery case (120) containing a metal material and the negative electrode current collector (111a) may come into contact.

[0194] Meanwhile, the tape adhesion process can be applied to the electrode assembly (110) using a fixing tape (340) comprising a base film (341) and an adhesive layer (342) provided on one side of the base film (341). In the tape adhesion process, the adhesive layer (342) of the fixing tape (340) may be made of a low-adhesion adhesive.

[0195] Here, for the tape adhesion process, for example, a fixing tape (340) may be used in which the adhesive layer (342) is an acrylic adhesive that is a low-adhesion adhesive. At this time, the tape adhesion process may further reduce the adhesive strength by including a curing agent in the adhesive layer (342).

[0196] Meanwhile, as another example of the tape adhesion process, a fixing tape (340) with reduced adhesion can be used by reducing the thickness of the adhesive layer (342) so that the adhesion strength is low. In this case, for example, the thickness of the adhesive layer (342) can be reduced by more than 50%.

[0197] In addition, as another example of the tape adhesion process, a fixing tape (340) can be used in which a hardener is added to the adhesive layer (342) to lower the adhesive strength. That is, the adhesive layer (342) can be cured through the hardener, thereby lowering the adhesive strength. Here, the hardener may be, for example, an isocyanate. Also, the adhesive strength can be controlled by adjusting the type and ratio of the hardener.

[0198] Meanwhile, the tape adhesion process may, for example, involve attaching a fixing tape (340) across the upper and lower parts of the outer surface of the electrode assembly (110). Here, the fixing tape (340) may be attached along the longitudinal direction of the electrode assembly (110). At this time, the fixing tape (340) may be formed in a rectangular shape and attached across the wound end of the electrode assembly (110) and the periphery of the wound end.

[0199] Additionally, as another example of the tape adhesion process, a fixing tape (340) can be adhered to the upper and lower parts, respectively, on the outer surface of the electrode assembly (110). Here, the fixing tape (340) can be adhered along the width direction of the electrode assembly (110).

[0201] < Experimental Example >

[0202] FIG. 8 is a photograph showing the state of the fixing tape before it reacts with the electrolyte in the secondary battery of the present invention, and FIG. 9 is a photograph showing the state of the fixing tape after it has reacted with the electrolyte and dissolved in the secondary battery of the present invention. Here, FIG. 8 is a photograph showing the state immediately after the fixing tape is impregnated with the electrolyte, and FIG. 9 is a photograph showing the state after 1 hour has elapsed after the fixing tape is impregnated with the electrolyte.

[0203] Referring to FIGS. 8 and 9, a fixing tape (T) applied to the secondary battery of the present invention was impregnated with an electrolyte and a dissolution test was performed on the fixing tape (T).

[0204] Here, DMC (dimethyl carbonate), EMC (ethylmethyl carbonate), and EC (ethylene carbonate) were used as solvents for the electrolyte.

[0205] Also, the fixing tape (T) used TPU (Thermo Plastic Polyurethane) tape.

[0206] As shown in FIGS. 8 and 9, a fixing tape (T) containing a reactive substance that reacts with the electrolyte and dissolves is used to prevent the electrode assembly from unwinding. When the electrode assembly is placed in a battery case containing the electrolyte, the fixing tape (T) dissolves, causing the electrode assembly to unwind. Consequently, it can be seen that the electrode assembly unwinds, filling the space between the battery case and the electrode assembly, and that when the electrode assembly unwinds, the outermost surface of the electrode assembly can come into contact with the inner surface of the battery case.

[0208] Although the present invention has been described in detail through specific embodiments, this is for the purpose of specifically explaining the invention and the invention is not limited thereto. It should be understood that various implementations are possible by those skilled in the art within the technical scope of the present invention.

[0209] In addition, the specific scope of protection of the invention will be clarified by the appended patent claims. Explanation of the symbols

[0211] 100,200: Secondary battery 110: Electrode assembly 111: Cathode 111a: Cathode current collector 111b: Cathode active material 112: Bipolar 112a: Positive current collector 112b: Positive active material 113: Electrode 114,115: Separator 120: Battery case 121a: Reception section 130: Electrode tab 131: Positive tab 132: Cathode tab 140,240: Fixing tape 141,241: Record film 142,242: Adhesive layer 160: Top Cap C: Central axis I: Center of the coil O: Outer edge of the winding E: Space

Claims

Claim 1 The electrode assembly comprises electrodes and separators alternately stacked and wound; a battery case containing the electrode assembly and an electrolyte; and a fixing tape attached to the outer surface of the electrode assembly to prevent unwinding, wherein the fixing force of the fixing tape that suppresses unwinding is weakened when impregnated with the electrolyte, so that the winding of the electrode assembly is unwound and the space between the battery case and the electrode assembly is filled, the electrode comprises a positive electrode and a negative electrode, the negative electrode is wound on the outermost surface of the electrode assembly and comes into contact with the inner surface of the battery case when the winding of the electrode assembly is unwound, the negative electrode comprises a negative current collector and an active material provided on one surface of the negative current collector, the negative current collector is positioned on the outermost surface when the electrode assembly is wound and comes into contact with the inner surface of the battery case when the winding is unwound, the inner surface of the battery case comprises a metal material, and the fixing tape comprises a base film; A secondary battery comprising an adhesive layer provided on one side of the above-mentioned base film, wherein the adhesive layer comprises a reactive substance that reacts with and dissolves in the electrolyte, so that the adhesive force is lost when the electrolyte is received and the base film dissolves when the electrolyte is received, thereby releasing the inhibition of unwinding of the electrode assembly through the fixing tape, and wherein the reactive substance is made of TPU (Thermo Plastic Polyurethane) that reacts with and dissolves in the electrolyte. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A secondary battery according to claim 1, wherein the adhesive layer comprises an acrylic adhesive which is a low-adhesion adhesive, and the adhesive strength is reduced when impregnated with the electrolyte so that the winding of the electrode assembly is unwound. Claim 7 A secondary battery according to claim 1 or claim 6, wherein the adhesive layer further comprises a curing agent to have low adhesive strength. Claim 8 In claim 1, the fixing tape is a secondary battery that is adhered to the upper and lower parts of the outer surface of the electrode assembly. Claim 9 A secondary battery according to claim 1, wherein the fixing tape is adhered to the upper and lower portions of the outer surface of the electrode assembly, and is adhered to the wound end of the electrode assembly and the periphery of the wound end. Claim 10 delete Claim 11 delete Claim 12 A winding process for forming an electrode assembly by alternately stacking and winding electrodes and separators; and a tape application process for applying a fixing tape to the outer surface of the electrode assembly to prevent unwinding. The method includes a receiving process for receiving the electrode assembly and the electrolyte inside the battery case, wherein, in the tape adhesive process, the fixing tape is used such that the fixing force suppressing unwinding is weakened when impregnated with the electrolyte, and as the fixing force of the fixing tape is weakened when the electrolyte is received in the receiving process, the winding of the electrode assembly is unwound and the space between the battery case and the electrode assembly is filled, the electrode includes a positive electrode and a negative electrode, and the winding process is performed such that the negative electrode is positioned on the outermost surface of the electrode assembly, and when the winding of the electrode assembly is unwound in the receiving process, the inner surface of the battery case and the negative electrode come into contact, and the negative electrode includes a negative current collector and an active material provided on one surface of the negative current collector, and the winding process is performed such that the negative current collector is positioned on the outermost surface of the electrode assembly, and when the winding of the electrode assembly is unwound in the receiving process, the inner surface of the battery case containing a metal material and the negative current collector come into contact, and the tape adhesive process is performed such that a reactive material that reacts with and dissolves with the electrolyte A method for manufacturing a secondary battery comprising: using a fixing tape including a base film and an adhesive layer provided on one side of the base film to adhere to the electrode assembly, wherein the adhesive layer includes a reactive material that reacts with the electrolyte and dissolves, the adhesive force is lost when the electrolyte is received and the base film dissolves when the electrolyte is received, and the winding of the electrode assembly is unwound as the base film dissolves when the electrolyte is received during the receiving process, and the reactive material is made of TPU (Thermo Plastic Polyurethane) that reacts with the electrolyte and dissolves. Claim 13 A method for manufacturing a secondary battery according to claim 12, wherein the tape adhesion process involves adhering the fixing tape to the upper and lower parts of the outer surface of the electrode assembly. Claim 14 A method for manufacturing a secondary battery according to claim 12, wherein the tape adhesion process involves adhering the fixing tape across the upper and lower portions of the outer surface of the electrode assembly, and adhering it across the wound end of the electrode assembly and the periphery of the wound end. Claim 15 delete Claim 16 delete Claim 17 A method for manufacturing a secondary battery according to claim 12, wherein the tape adhesion process involves using a fixing tape comprising a base film and a reactive substance that reacts with and dissolves the electrolyte, and an adhesive layer provided on one side of the base film, to adhere to the electrode assembly, and wherein, during the receiving process, the adhesive force is lost as the adhesive layer dissolves when the electrolyte is received, thereby unwinding the electrode assembly. Claim 18 delete Claim 19 A method for manufacturing a secondary battery according to claim 12, wherein the tape adhesion process involves using a fixing tape comprising an adhesive layer provided on one side of a base film, the adhesive layer comprising a base film and an acrylic adhesive which is a low-adhesion adhesive, to adhere to the electrode assembly, and during the receiving process, the winding of the electrode assembly is unwound as the adhesive strength of the adhesive layer decreases when impregnated with the electrolyte. Claim 20 A method for manufacturing a secondary battery according to claim 12, wherein the tape adhesion process involves using a fixing tape comprising a base film and an adhesive layer provided on one side of the base film containing a curing agent to lower the adhesive strength, and the electrode assembly is unwound as the adhesive strength of the adhesive layer decreases when impregnated with the electrolyte during the receiving process.

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